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This report was prepared as a n account of work sponsored by the United States Government. Neither the United States nor the United States Atomic Energy Commission, R Q P any sf their employees, nor any of their contractors, subcontractors, tkerr employees, makes any warranty, express or implied. or assumes any legal liability responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process dcsclosed, or represents that its use W Q U I ~ nut infringe privately owned rights.

OWML-5 018 UC-76 -Molten Salt Reactor Technology

Contract No. W-7465-eng-26

P R O G W PIAN

FOR

DEVELOPmNT OF MOLTEN-SALT BWEDER REACTORS

L. E. McNeese artla

Staff of t h e Molten-Salt Reactor Program

DECEMBER 1974

OAK RIDGE NATIONAL LABOUTORY

Oak Ridge, Tennessee 37830 operated by IBE COBPOWTION for t h e U e S eATOpa3cC ENERGY COMMISSION

..... u . . . .

CONTENTS Page

1-1 ... .. .... .. 1-1 ED DEVaQPmm P- 2 ACTIVITIES . .. ... ... .. 1.2.1 Developmnt of structural metal for primary and secondary circuits . . . . 1-2 1 . 2 . 2 Fuel processing . . .. .. 1-4 1 . 2 . 3 Fuel processing materials development . . 1-5 1.2.4 Chemical research and development . . 1-7 1.2.5 Analytical research and development . . . . . . 1-9 1-10 1.2.6 Reactor safety . .. . 1.2.7 Reactor design and analysis .. . . 1-11 1.2.8 Graphite development . . . - 1-13 1-14 1.2.9 Weactor technology development . . .. 1.2.10 Maintenance .. .- ... . . 1-15 1-17 1.2.11 Instrumentation and controls development . B,2.l2 Mdten-Sa1t Test Reactor mockup . . . 6-17 1,2.13 MoHten-Salt T e s t Reactor . . . 1-18 1.2.14 Molten-Salt Demonstration Reactor . .. . 1-E9 1.3 KEY PROGRAM MILESTONES .. . ... . . 1-19 STIWTED FUND BEQUIMmNTS . .. . 1-19

1. P R O G M PLAN OVERVIEW

...

1.1 INTRODUCTION BESB S W Y 1.2 STATUS OF TECHNOLOGY Am e

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DErnLOPMEMT OF SrnUCTUML rnT& AND SECONDARY CIRCUITS a 2.1 ImRoDuCTIoN * * *

FOR PRIWRY

. . 2-1 .. . 2-1 2.1.1 Objective . . . 2-1 2.1.2 S c o p e . . . 2-1 2.2 P R O G W BUDGET WEaB SCHEDULE . . . . . . 2-3 2.2.1 ScheduPe and key program milestones . . 2-3 2.2.2 mwaing . . .... 2-3 2.3 MATERIAL BACKGROUND, AND STATUS OFDEmLOPmm.. . - . 2.3.1 Material requirements . . . . . . . . . . . 2-3 2-3 2.3.2 Background ... . .. .... 2-8 2 . 3 . 3 Status of development . . . . . . . . . . . . . 2-13 2.4 TASK GROUP 1.1 ~ E T E ~ ~ OF ~ AALLOY ~ I CBWBSITIQN ~ N . . . . 2-19 2.4.1 Objective . .... . . 2-19 2 . 4 . 2 Schedule . . .. .. ... 2-19 2.4.3 Funding . . .... . .. . . . . . 2-23 2.4.4 Facilities . .. . . . . . . . 2-23 .

~~~~~~~~~~

* .

2.4.5 2.4.6

. .. . . -

2.4.5

2.4.8

Task 1.1.1 PPOcUPWER~Of test TIlZ3te%hlse Task 6.1.2 Baeie studies OR interaction of tellurium with H a s t e l l o y E9 Task 1.1.3 Effects of fission products OW lll@chaEliCal pKOperti6iS e e Task 1.1.4 me-1 convection corrosion tests s * * * * * * s . e . . D

2-23

2-26

2-2a

2-28

Page

2.5

. . 2-29 2-30 . . .. . 2-31 . .~ 2-33 ~ -. . .. ... . 2-34 2-34 2-34 . . . . . 2-34 . . 2-34 . . . 2-34

2.4.9 Task 1.1.5 Forced convection corrosion tests 2.4.10 T a s k 1.1.6 I n - r e a c t o r f u e l e d capsule tests 2.4.11 Task 1.1.7 Irfadiatio~membrittlement of HasteBloy N e TASK GROUP 1.2 P R OF C O W R~C I A L H U T~S 2.5.1 O b j e c t i v e * * , * * s ' 2.5.2 Schedule * 2.5.3 Funding s * * 2.5.4 Task 1.2.1 Specifications 2.5.5 Task 1.2.2 Bidding and vendor s e l e c t i o n s 2.5.6 Task 1 . 2 . 3 S u r v e i l l a n e e of f a b r i c a t i o n 2.5.7 Task 1.2.4 Receipt and c a t a l o g i n g of e

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. .. .. .. ... .. .. .. 0

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2-34 . .. 2-36 . . . . .. .. 2-36 . ... ... . . . . 2-36 .. .

material * . TASK GROUP 1.3 EVALUATION OF COMMERCU HEATS e

2.6

2.6.1 2.6.2 2.6.3 2.6.4

Objective e e e schedule Funding. e * Facilities e 2.6.5 Task 1.3.1 W e l d a b i l i t y 2.6.6 Task 1 , 3 . 2 NechanicaE p r o p e r t y tests * 2.6.7 Task 1.3.3 P h y s i c a l property measurements 2 6.8 Task 1.3.4 Thermal convection corrosion tests * * * 2.6.9 Task 1.3.5 Forced convection: c o r r o s i o n tests 2.6.10 Task 1 . 3 . 6 I n - r e a c t o r f u e l e d capsule tests e 2.7 TASK GROUP 1 . 4 DEVELOPmNT OF BMALYTICAL DESIGN METHODS - ASHE CODE CASE SUBFfISSIQN 2.7.1 O b j e c t i v e 2.7.2 Schedule * s * 2.7.3 Funding s * n * * 2.7.4 Faci12ties , 2 . 7 . 5 Task 1.4.1 Data analysis 2.9.6 Task 1.4.2 Development Of d e s i g n mehods 2.7.7 Task 1 . 4 . 3 Submission of code case 2.8 TASK GROUP 1 . 5 LONG-TERM MATERIALS TEST 2.8.1 O b j e c t i v e * a 2 . 8 . 2 Schedule s * * 2 . 8 . 3 Funding * * 2.8.4 Facilities * 2.8.5 Task 1.5.1 Mechanical p r o p e r t y tests e 2.8.6 Task 1.5.2 Forced c i r c u l a t i o n loops * * 2.8.7 Task 1 - 5 . 3 'En-reactor f u e l e d c a p s u l e tests 2.9 TASK GROUP 1 . 6 HATERIAL OPTIMIZATION 2.9.1 Objective , a s * * 2.9.2 Schedule * 2 . 9 . 3 Funding * * * s * s 2.9.4 Facilities 2.9.5 Task 1.6.1 F u r t h e r H a s t e l l s y N improvement 2.9.6 Task 1 . 6 . 2 C o n s i d e r a t i o n of other materials REFERENCES FQR SECTION 2 e

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. .. . . . . .. .. . .. . . . . . .. . . . 3-1 3-1 . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3-1 .. .. . . . . . . . . . . . 3-3 3-3 3-3 . . . . . . . . . . . . . 3-8 .. . . . . . . 3-8 . . . . . . . . .. .. . . .. .. .. .. . 3-15 3-8 . . . 3-28 . . . . . . . . . . . . . . 3-20 . . . . . . . . . . . . . . . 3-20 ... ... ..... . . 3-20 ... ... 3-23 . . . . . . . . .. 3-23 . . . . . . . . .. .. .. .. .. . . . 3-23 3-23

FUEL PRQCESSING e e e e e * 3 . 1 INTRODUCTION e e e a e a e e 3.1.1 Objective e e e e a e e 3 . 1 . 2 Scope e e * * e * e * 3 . 2 B R Q G W BUDGET AND SCHEDULE e e e e e e e 3 . 2 . 1 Schedule and keg program m5lestones e 3.2.2 Budget * e e * e TS, BACKGROWB, AND STATUS OF DEVELOPMENT e a 3 * 3 REgn1 e e e e e 3.3.1 P r o c e s s i n g requirements 3.3,2 Background e e e e 3 . 3 . 3 S t a t u s of development e e e e e 3 . 4 TASK GROW 2.1 FLQWSPIEET ANALYSIS AND DEVELOPNEXT * 3 . 4 . 1 Objective e e e e e e 3 . 4 . 2 Schedule * e e e c * e * e 3.4.3 F m d i n g . e e 3 . 4 . 4 Task 2.1.1 H e a t b a 1 m c e s e e e e 3 . 4 . 5 Task 2.1.2 Mass balances e e e 3 . 4 . 6 Task 2.1.3 P a r m e t r i c a d optimization * e e * e * * studies 3.4.7 Task 2.1.4 Waste c h a r a c t e r i z a t i o n a 3 . 4 . 8 Task 2.1.5 P r o c e s s i n g p l a n t conceptual design and cost estimate e e e e 3 . 4 . 9 Task 2.1.6 P r o c e s s i n g system c o n t r o l e 3.4.10 Task 2.1.7 k s o u r c e requirements and utilization e e e e a e e e A l t e r n a t e p r o c e s s development e e 3 . 4 . 1 1 Task 2.1.8 3 . 5 TASK GROUP 2.2 CONTINUOUS 'PLUORPUTOR DEVELOPMEHT e a e 3.5.1 O b j e c t i v e e e e e e a e 3.5.2 Schedule a e e * e 3.5.3 F m d h g . . e e e e . . 3.5,4 Facilities a e e e e 3.5.5 Task 2.2.1 Nonradioactive h e a t g e n e r a t i o n studies. e e e 3.5.6 Task 2.2.2 F l u o r i n a t i o n chemistry e 3.5.7 Task 2.2.3 Frozen wall c o r r o s i o n p r o t e c t i o n studies. e e a e 3 . 5 . 8 Task 2.2.4 Mass t r a n s f e r i n open bubble 0

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.. .. . 3-24 3-24 . . . . . . . . . . 3-24 . . . 3-25 3-25 .. .. . .. .. . .. .. .. . .. .. . . .. .. 3-25 3-25 .. .. .. . . .. .. . .. .. .. . - .. . .. . . 3-27 3-27 . . . . . . . . . . . .. .. . . . .. . 3-27 3-38 t

. . . . . . . . . . . . . . . . 3-30 cofwws. .... .. 3-31 3.5.9 Task 2 . 2 . 5 C h a r a c t e r i z a t i o n of t h e Fz-Hz reaction . . . . . . . . . . . . . . . . . 3-31 3.5.10 Task 2.2.6 Continuous Fluorinator Experimental F a c i l i t y . . . . . . . . . . . . . . . . . . . * *3-31 3 . 5 . 1 1 Task 2.2.7 F l u o r i n ~ t i o n - I P e c o n s t i t u t i o n Engineering F a c i l i t y . . . . . . . . . . . . 3-33 3 . 6 T A S K GROW 2 . 3 FUEL RECONSTITUTION . . . . . . . . . .. .. .. .. .. .. . . 3-34 3-34 3.6.1 Objective . . . 3.6.% Schedule 3-34 3.6.3 Funding. . . - . . 3-34 3.6.4 F a c i l i t i e s . . . . . . . . . . .. 3 . 6 . 5 Task 2.3.1 Fuel r e c o n s t l t u t i o n chemistry . . . . 3-37 3-37 e . .

* . .

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3-38 3-38 3-40 3-40 3-40 3-42 3-42 3-42 3-45 3-45 3-47 3-49 3-49 3-49 3-49 3-49 3-52 3-52 3-52 3-56 3-56 3-54 3-56 3-58 3-58 P-58 3-33 3-58 3-58 34o 3-m 3-m 3-m

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FUEL-PROCESSING WTEWP&S BEVELQPME" e 4 . 1 IMTR(BDUCTI0N * e * * e 4.1.1 Objective e e s s e e e 4.1.2 Scopes e e s e . . * . * e s BUDGET AND SCHEDULE e e e e 4.2.1 Schedule and key program milestones e 4.2.2 Funding.. * * e * e * 4 . 3 M T E W I f i mQuI NTS, BACKGRQUND, AMD SIPATUS OFDEVELOPBENT. e e e . 4.3.1 Haterials requiremnts e e c s 4 . 3 . 2 Background * * * 4 . 3 . 3 S t a t u s sf development e 4 . 3 . 4 Basis for materials s e l e c t i o n e e e e 4.4 TASK GROUP 3.1 BETE INATION OF CORROSI(%Ea-RES%STANT rnTERIALS * e . . * c e 4.4.1 Objective * e 4 . 4 . 2 Schedule e e e e e e 4.4.3 Fmding a * s 4.4.4 Facilities e s * a * * * 4.4.5 Task 2.1.1 C o m p a t i b i l i t y of m l y b d e n m with molten s a l t s and B i - L f - r n solutions e * 4.4.6 Task 3.1.2 C o m p a t i b i l i t y of graphite with B i - L i - r n soPutiont3 n * e e e * 4.4.7 Task 3.1.3 C o m p a t i b i l i t y of tantalum and tantalum d l c p y s w i t h molten salts and BI-L% solutians , * 4 , e e * a e 4 . 4 . 8 Task 3 . 1 . 4 Compatibility of braze d 1 o y s with molten s a l t s and Bb-Li-1Fta solutions a e c * s a

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Task 2.8.4 construction * * 3.11.8 Task 2.8.5 Acceptance of f a c i l i t y 3.12 TASK GROUP 2.9 INTEGRATED PROCESS TEST FACILITY 3.12.1 O b j e c t i v e a e e 3.12.2 S c h e d d e s a e e m e * s rn 3 . 1 2 . 3 Funding e s * 3.12.4 Facilities * * s 3 12 5 Task 2 9 1 D e f i n i t i o n of experimental program and preaiminapy design * * a s 3.12.6 Task 2 . 9 . 2 Development work required f o r design. * . s * a 3.12.7 Task 2 . 9 . 3 Conceptual design e 3.12.8 Task 2.9.4 Title I d e s i g n a 3.12.9 Task 2.9.5 T i t l e I1 d e s i g n * 3.12.10 Task 2.9.6 Equipment f a b r i c a t i o n e 3.12.11 Task 2.9.7 Equipment i n s t a l P a t i o n e 3.12.62 Task 2 . 9 . 8 I n i t i a l t e s t i n g and o p e r a t o r training. e e e e e e 3.12.13 Task 2.9.9 Operation e e e e F U L F E ~ N C E SFOR SECTION 3

3.11.9

Page 4.5

TASK GROUP 3.2 BEVELOP~NT OF FAl3BICATION AND JOINING TECHNIQUES .................... 4.5.1 Objective ..................... 4.5.2 Schedule ..................... 4.5.3 Fuding ...................... 4.5.4 Facilities .................... 4.5.5 Task 3.2.1 Pabrisation development sf ......... mslybdenurn and molybdenum alloys 4.5.6 Task 3.2.2 Fabrication devefgspmewt of ........... tantalum and tantalum alloys 4.5.7 Task 3.2.3 Fabrication development of graphite ..................... 4.5.8 Task 3.2.4 Joining aaf rmlybchum ad ................. molybdenum alloys 4.5.9 Task 3.2.5 Joining of tantalum alloys ...... 4.5.10 Task 3.2.6 Joining of graphite .......... 4.6 TASK GROUP 3.3 CONSTRJJCTIQN OF ENGINEERING FUEL PJBXESSIMG EXPERIHENTS .................. 4.6.1 Objeetfve ..................... 4.6.2 Schedule ..................... 4.6.3 Funding ...................... 4.6.4 FaeiPities .................... 4.6.5 Task 3.3.1 Continuous Fluorinatsr Experimental FaciBity ..................... 4.6.6 Task 3.3.2 Fluorination-Be@anstitution Engineering Facility ............... 4.6.7 Task 3.3.3 Reduction Extractisn Process Facility ..................... 4.6.8 Task 3.3.4 Metal Transfer Process Facility .... 4.6.9 Task 3.3.5 Integrated Prstxss Test Facility ... REFERENCES F6R SECTION 4 ................... 5.

CHEMICAL l?E%EMCH AND BEVELOP~NT ............... ....................... 5.1 INTRXWCTION 5.1.1 Objective ..................... 5.1.2 scope ....................... 5.2 PROGKAM BUDGET AFill SCHEDULE ............... ........ 5.2.1 Schedule and key program milestsnes 5.2.2 Budget .sLxIimaq .................. 5.3 REQUITES, BACKGRNJND AND STATUS OF DEV'ELOPmm 5.3.1 Requirements ................... 5.3.2 Background .................... ............... 5.3.3 status of develspmnt 5.4 TASK GNXJP 4.1 FUEL SALT CZXFXISTRY ........... 5.4.1 5.4.2 5.4.3 5.4.4 5.4.5

Qbjective Ssikedu%e Funding

..................... ..................... ......................

Facilities .................... Task 4.1.1 SolubfPity axides ...................... Viii

products

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4-22 4-22 4-22

4-22 4-22 4-29 4-30 4-31 4-32 4-33 4-34 4-36

4-36 4-36 4-36 4-36 4-36 4-39 4-39 4-40 4-41 4-42 5-1 5-1 5-1 5-P 5-2 5-2 5-2 5-2 5-2 5-7 5-8 5-17 5-167 5-18 5-18 5-18

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Task 4 . 1 . 2 T e l l u r i u m chemistry e Task 4 + 1 . 3 Phase b e h a v i o r s f Pup3 i n fuePsa1t e 5 . 4 . 8 Task 4 . 1 . 4 Fuel-coolant i n t e r a c t i o n s t u d i e s 5.4.9 Task 4.1.5 Physical property determinations onfuelsalt . . . . . . . . . e . s . s e . 5.4.10 Task 4.1.6 U3*/U4+ e q u i l i b r i a s t u d i e s TASK GROUP 4 . 2 COOLmT SALT CHENICSTRY e 5.5.9. Objective m * * * ' * * 5.5.2 Schedule 5.5.3 Funding s * s 5.5.4 Facilities e 5.5.5 Task 4 . 2 . 1 Qxide and hydroxide chemistry of f l u o r s b o r a t e 5.5.6 Task 4 . 2 . 2 Corrosion chemistry of fluoroborate e a 5.5.7 Task 4 . 2 . 3 Coolant p u r i f i c a t i o n * 5 . 5 . 8 Task 4 . 2 . 4 Alternate coolant e v a l u a t i o n 5.5.9 Task 4.2.5 Physical property d e t e d n a t i s n s oncooPants....... TASK GRQUP 4 . 3 TRITIUM BEHAVIOR e e 5.6.1 O b j e c t i v e e 5 . 6 . 2 Schedule s e * s e 5 . 6 . 3 Funding * s * 5.6.4 Facilities e 5.6.5 Task 4 . 3 . 1 Permeation s t u d i e s 5.6.6 Task 4 . 3 . 2 S o l u b i l i t y of t r i t i u m - c o n t a i n i n g species i n molten s a l t s e 5.6 e 7 Task 4 3 . 3 E q u i l i b r i a between i m p o r t a n t s p e c i e s c o n t a i n i n g t r i t i u m i n salt-gas system 5.6.8 Task 4 . 3 . 4 I s o t o p i c exchange between t r i t i u m and chemically bound hydrogen 5 . 6 . 9 Task 4 . 3 . 5 TF c o r r o s i o n b e h a v i o r a t l o w a

.. .. . . .. .. . ... .. ... .. .. . .. .. .. . . .. .. . . ... .. . .. . . . . . .. .......... ... 5.6 . .. . . . .. ... ... . .. .... .. . ..... . . .. . . . .. . . . .- . TPactivity .. ... .. . 5.6.10 Task 4.3.6 Diffusivity studies . . 5.6.11 Task 4 . 3 . 7 Modeling of tritium b e h a v i o r in m o l t e n - s a l t reactors ....... . 5.6.12 Task 4 . 3 . 8 T r i t i u m a d s o r p t i o n on carbon i n contact with the coolant . .. ... TASK GROUP 4 . 4 FISSION PEBBIICT CHEMISTRY . .. 5.7 5.7.1 Objective . . ........ .. 5.7.2 Schedule .. .. .. .. -. . .. .. . .. .. 5 . 7 . 3 Funding . . 5.7.4 Facilities . .. ... ...... 5.7.5 Task 4 . 4 . 1 Noble metal chemistry .,.. 5.7.6 Task 4 . 4 . 2 I o d i n e d i s t r i b u t i o n . .... s

5-27

5-30 5-38 5-34 5-35 5-37 5-37 5-37 5-37 5-37 5-37

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5.7.8

Task 4 . 4 . 4 Analysis of f i s s i o n product d e p o s i t i o n d a t a from PISRE Task 4 . 4 . 5 S t u d i e s i n t h e Gas-System Teehnohgy F a c i l i t y (GSTF)

5.7.9

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6-42 6-42 6-42 6-42 6-47 6-47 6-54 6-56

6-59 6-60 6-60 6-60 6-60 6-6 6-60 6-66

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6-83 6-82 6-84

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6-88 6-88 6-88 6-88 6-89 6-89 6-89 6-89 6-89

6-93 6-52 5 6-98 6-%q0

6-100

Page

7-1 7-1 7-1 7-1

7-4 7-4 7-4 7- 6 7-6 7-6

7-6 7-8 7-22 7-26 7-26 7-26 7-29 7-29 7-30 7-31

151-r

7-31 7-31 7-32 7-32 *

9-32

7-35 7-36 7-36 7-36 7-36 7-36

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7.6.7

Salt b e h a v i o r a t extreme

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TASK GROUP 6 . 4 CQW8MEm AND SPSTEB TEmNOLOGP 7.7.1 Objectives e e 7.7.2 Schedule and funding e e e e * 7.7.3 Facilities * e * e e s e 7.7.4 Task 6 . 4 . 1 Contaimment systems e e e 7.7.5 Task 6 . 4 . 2 Seismic technology * e 7.7.6 Other safety teshnslo tasks * e e e

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7-45

TASK GROUP 6.5 SAFETY LNSTRmNTATHON aEJB COMTRQLS 7.8.1 O b j e c t i v e

7-45 .. ..... ... 7-45 7.8.2 Schedule and funding .. . 7-45 9.8.3 Facilities . . . . . . .. 7.8.4 Task 6.5.1 I d e n t i f i c a t i o n of i n s t r u m e n t a t i o n 7-45 and c o n t r o l s s a f e t y needs . .... .. 7-46 7.8.5 Technology development tasks . . . . . 7-46 7.9 TASK GROUP 6.6 MAINTENANCE TECHNOLOGY . .. . 7-46 9.9.1 O b j e c t i v e s . . .... . . ... 7-46 7.9.2 Schedule and funding .. .7-46 7.9.3 Facilities . . . . . . . . . . . . 7.9.4 Task 6.6.1 Development of maintenance 7-4a te&ROlogy t o edlanCe Safety . . . . 7.10 TASK GROUP 6.7 SAFETY TECHNOLOGY OF PROCESSING AND 7-47 WASTE STORAGE AND HANDLING . . . . . , . 7-47 7.10.1 O b j e c t i v e . . ...... . .. 7-47 7.10.2 Schedule and funding . ... ... 7-47 7.10.3 F a c i l i t i e s . . . 7-48 REFERENCES FOR SECTION 7 ... .. . . 8-1 8. REACTOR DESIGN AND ANLYSIS ....... ..... 8.1 ImRODuGTI063 . . . . . . . . . . . . 8-1 8.1.1 O b j e c t i v e ..... . .. . 8-1 8-1 8.1.2 S c o p e . ....... ... 8.2 PROGW BUDGET AND SCHEDULE .. . .. 8-3 8-3 8.2.1 Schedule . .. .... .... 8.2.2 Budget . . . . . . . . . 8-9 8-7 8 . 2 . 3 Key program m i l e s t o n e s . . . . . . . 8-9 8 . 3 BACKGROUND AND STATUS . .. 8.3.1 Primary s y s t e m l a y o u t and s t r u c t u r a l d e s i g n . 8-10 8-11 8.3.2 Design methods . ... ... . 8-12 8.3.3 C a p i t a l c o s t s . . . . . 8.4 TASK GROUP 7.3. DESIGN STUDIES OF MSR POWER PLANTS . . 8-12 8.4.1 O b j e c t i v e . . . . . . . . . . . . . . 8-12 8.4.2 Schedule . . . . . . . . . . . . . . 8-13 8-13 8.4.3 Funding. .. 8.4.4 Task 7.1.1 O W L s t u d i e s of 1000-MW(e) E B R . . . 8-13 I n d u s t r i a l studies of 1060-MW(e) 8.4.5 Task 7.1.2 8-19 MSBR . .. . . . . . . . . 8-20 f3.4.6 Task 7.1.3 O m s t u d y o f PlISTR . ... .. 8-20 8.4.7 Task 7.1.4 I n d u s t r i a l s t u d y of MSTR . . . . 8.4.8 Task 7.1.5 S t u d i e s of alternate d e s i g n s and u s e s of PIISR's . . . . . . . .. . .. .. .. . 8-20 8-21 8.5 TASK GROUP 7.2 DESIGN TECHNOLOGY . 8.5.1 O b j e c t i v e s . . . . . . . . . . . . 8-21 8-21 8.5.2 Schedule . . . . 8.5.3 Funding . . . . . .. .- .. .. . .. .. .. .. . . 8-21 8.5.4 Task 7 , 2 . 1 E s t a b l i s h d e s i g n b a s e s and methods for equipment for 1300°F o p e r a t i o n . . 8-24 a

... .... & E% :

...

... ,&

.... .... L*L&

Task 7.2.2

Compile d e s i g n p r o p e r t i e s

.... ,:.;.;.>

xiii

8.5.5

8-24

Page

8-25

8-26

8-26 8-26 8-26

8-27 8-27 8-27

8-30 8-30 8-38 8-38 - 31 8-31 8-31

8-33 8-33 8-33 8-33 -33 -36 -36 -36 8-38

9-1 9-1 9-1 9-1 9-3 9-3 9-3

9-3 9-3 9-8 9-14 9-16 9-16 9-17 9-17 9-17

9-17

&.,.

.,.,.,..

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Page

....

9-17 9-19 9-21 9-21 9-21 9-21

.... s&

... t a

9-21 9-25

9-26 3-27 3-27 9-27 9-27 9-27 9-29

9-31 9-31 9-32 9-32

9-32 9-32 9-32 9-32 9-35 9-35 9-35 9-36 9-36 9-36 9-36

9-36 9-39 9-40

10.3

EXPERIENCE AND STATUS OF DEVELOPmNT Fuel s a l t technology development Coolant salt te&noHow development Steam-system t e ~ h ~ l o gdevelopment y 18.3.4 Cover and off-gas system t e e h n s l o e e

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. .. . ... .. .. . .. . .. .. . . .. . . . .. .... ...... ... . . . . .. .... . .. . .. . . . 0

10.5

. . ...

deve1opment s e e S a l t pump development e e B ~ i m a qs a l t - s d t h e a t exchanger development * * * e a e * 10.3.7 Valve development * 10.3.8 C o n t r o l rod development * e e s 10.3.9 Containment a d cell heating development TASK GROUP 9 . 1 FUEL SaLT TECHNOLOGY DEaLOPPaENT ,. 10.4.1 O b j e c t i v e * * * s ' e * 10.4.2 Schedule 18.4.3 Funding e , 10.4.4 F a c i l i t i e s e * * ' e * * 10.4.5 Task 9.1.1 Gas-System Technology F a c i l i t y water tests * 10 4 s 6 Task 9 e I* 2 Gas-Sys tern Technology F a c i l i t y fuel-salt studies e 10.4.7 Task 9.1.3 MteKheat b-emoval systems e ' * * * development 10.4.8 Task 9.1.4 S a l t sampler development e 18.4.9 Task 9.1.5 Parametric evaluation s t u d i e s f a r xenon removal e a TASK GROUP 9.2 COOLANT-SALT TECHNOLOGY DEVEEBBPIENT 10.5.1 O b j e c t i v e e * 10.5.2 Schedule * e e * * * 10.5.3 Funding * , rn * * 18.5.4 F a c i l i t i e s * e s s s s 10.5.5 Task 9.2.1 CSTF studies ( f l u o r o b s r a t e salt) s s e * * 10.5.6 Task 9 . 2 . 2 E v a l u a t i o n a d design of larger c o m p ~ n e n t~~ Q Kc o o l a n t - s a l t technology development e * * e ' * e TASK GROUP 9 . 3 S T E M TECEEMOLQGY D E V E L Q P ~ N T e 10.6,1 Objective s * s e e ' lbo.4.2 Schedule * * * e ' e s . * . 10.6.3 F u n d i n g . e 18.6.4 F a c i l i t i e s r . . . . 0 . . . . . * . * s . . e . 10.6.5 Task 9 3 1 Industrial s t e m generatOK CQnceptklaH design StUdi@% e 10.6.6 Task 9 . 3 . 2 Design s t u d i e s and sm%Iscale e x p l o r a t o r y development * r e 10.6.7 Task 9.3.3 Steam Generator Tube Test Stand design, c o n s t r u c t i o n , and o p e r a t i o n * s 60.6.8 Task 9 . 3 . 4 Nodel t e s t i n g i n t h e S t e m G e n e ~ a t o rHodel T e s t I n s t a l l a t i o n ( S n r S I > (Subtasks 9.3.4.1 through 9.3.4.13.) e 10.3.5 18.3.6

10.4

l0.3.1 10.3.2 10.2.3

.. .

b.&h

Page Task 9.3.5 Equipment and c o n t r o l s c r i t e r i a development , , 10.7 TASK GROUP 9.4 COVER- AND OFF-GAS SYSTEM TECHNOLOGY DEVELOPMENT. e a 1Q.7.1 Objective 10.7.2 Schedule 10.7.3 Fundfng * * * * 10.7.4 F a c i l i t i e s , 163.7.5 Task 9 . 4 . 1 Handling of n o n - v o l a t i l e * constituents 18.7.6 Task 9.4.2 Handling of v o l a t i l e constituents TASK GROUP 9.5 SALT PUMB DEVELOPPlENT e 10.8 10.8.1 O b j e c t i v e e 10.8.2 Schedule 10.8.3 Funding e e 10.8.4 F a c i l i t i e s 10.8.5 Task 9 . 5 . 1 Development of s h o r t - s h a f t p u m p s . . . . . . . 10.8.6 Task 9.5.2 Development of molten-salte Lubricated bearings 10.9 TASK GROUP 9.6 PRIMABY SALT-SALS: HEAT EX(33ANGER DEWLOmENT. 10.9.1 O b j e c t i v e 10.9.2 Schedule e e 10.9.3 Funding e e e 10.9.4 F a c i l i t i e s 10.9.5 Task 9.6.1 S t a t u s of technology r e p o r t 10.9.6 Task 9 . 6 . 2 Define and p e r f o m development program.. * . * . . e * . 10.10 TASK GROUP 9.7 VALVE DEVELOPMENT * , 10.10.1 O b j e c t i v e e e 10.18.2 Schedule e 10.10.3 Funding * * 10.10.4 F a c i l i t i e s e , 3.8.10.5 Task 9.7.1 S t a t u s of technology r e p o r t 10.10.6 T a s k 9.7.2 D e f i n e and perform development program a e 10.11 TASK GROUP 9 . 8 CONTROL ROD DEVELOPMENT e 10.11*1 O b j e c t i v e ' * * 18.11.2 Schedule e a * 1 8 . 1 1 . 3 Funding e e e 10.11.4 F a c i l i t i e s e 10.11.5 Task 9 . 8 . 1 Define development program and c o n s t r u c t test f a c i l i t y e e 10.11.6 T a s k 9.8.2 Perform development program 10.12 TASK GROUP 9.9 CONTAINMENT AND CELL HEATING e 10.12.1 O b j e c t i v e e 10.12.2 Schedule m * * * * e 1 0 . 1 2 . 3 Funding e e 10.6.9

...... . . .. .. .. .... ...... . . ... ..... ... .. . . .... . .. .... . .. . . . .. ..... . . ... .. . . ... ...... . ... . .. . .. .. . . . .. .. .. -. . .. .. . . . ............ . . .. .. ... .... .. ... . . .. .... . .. ..... .. ... ... .. .. ... .... . . .. ...... ... . ........ .- . e

. . . . . . . . .- . . . .... ... .. .. ...... .... .. . . . .. . . . . . . . . .. . . . . .. . e

... ... se

10-61 10-64 1q-65

10-66 18-66 18-66 10-66 10-66 10-66 18-66 10-68 10-68

10-70

mii

10-61 10-61 10-61 10-61

10-59

10-68 10-6 8

60-55

10-55

l.0-6 8

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10-55 10-55 10-55 10-55

10-54

10- 70 10-70 18-70

10-71 10-71 10-71

PO- 7 3 PQ-73 10-73 10-73 18-73 10-73

Page

10.12.4 10.12.5 10.12.6

Facilities

Task 9.9.1

. a

10- 75 10-75 10-75 10-75

18-75 10-96 10-76 10-76

Define development p r o g ~ a m * Task 9.9.2 P e r f o r m development program 18.13 TASK GROUP 9.10 COMPONENTS TEST FACILITY e 10.13.1 Objective 10.13.2 Schedule = s * 10.13.3 PundEn 10 13 4 FaciBB i e s . a a 10.13.5 Task 9.10.1 Conceptual design of t h e %acility -18.2 Title I and T i t l e I% d e s i facility e s * s 10.13.7 Task 9 . 1 0 . 3 Construction of the facility 18.13.8 Task 9.10.4 Operation of the facility FErnNCES FOR SECTICIEJ 10 * r *

..............~.. . s

11.P 11.2 11.3

10-76

PO- 79 18-79 18-99

10-79

11-1 11-1 11-1 11-2 11-2

11-2 $1-2 11-2 11-2 ib%-lO 11-15

11.4

11-16 11-16 El-16 11-16

11-19 11-28

11-21 11.5 11-22

11-22 11-22 11-22 11-26 ...... "~

11-26 11-27

11-2 7

Page

11-28 11-28 11-29 11-29 11-29 11-29 11-29

11-29 11-33

11-33 11-34 11-36 12

12.1

12.1.2

12.2.1 12.2. .... L a

...

12.3

~ S AND CONTROLS ~ ~ DEVEEOPmNT ~ ~ INTRoDuC%PoM * * B2.1.l O b j e c t i v e * r *

. e

dget

REQUE 12.3.1

12-1 12-1 12-1

12-2 12-2

.~ 12-1 ~

Scope e e BUXET AND SCHEDULE e e e Schedule and key prcsgrm m i l e s t o n e s e

s ~

Requirements and c u r r e n t concepts * Experience with the mm and o t h e r facilities s * e * 12.3.3 S t a t u s of c o n t r o l analyses a * 1 2 . 3 . 4 s t a t u s of i n s t r u m e n t a t i o n development * e ' F A U X GROUP 11.1 coMTRoL rn&YSES * e s e 12.4.1 O b j e c t i v e a e e e * a = 12.4.2 Schedule * s e e * * * e e 12.4.3 FandLng * e * 12.4.4 Task H 1 , l . l Computer r e p r e s e n t a t i o n of pliant operation e e e a e e 12.4.5 Task 11.1.2 D e v e l o p ~ ~ ~ ofn tcontrol methods e 12e4.6 Task 11.1.3 F1uxmeasurement analyses c 12.4.7 Task 11.1.4 Calcu1ation of p r e s s u r e ana temperature t r a n s i e n t s e s * * 12.4.8 Task 11.1.5 B e t e d n a t i o n Of requirements f o r s a l t t h r o t t l i n g valves e e e a e e e 12.4.9 Task 11.1.6 Development of rn@thOdS f o r i n v e n t o r y accounting and e o n t r s l e e e e 12.4.10 Task 11.1.7 Evaluation of need for f a s t scram c a p a b i l i t y * e e e e 12.4.11 Task %%*1.8 D e t e d n a t i o n of proceasimg plant i n s t r u m e n t a t i o n needs * e e * * e e

12-2 12-3

12-6

12.3.2

12.4

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. . .. 0

e e

12-20 12-20

xix

12-8 12-18 12-14 12-16 12-16 12-16

. . . . 12-18 . . . . . 12-18 12-18 . . 12-18 . . . . 12-20 ... . 12-20 a

12-21

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12-21 12-21 12-21 12-21 12-21 12-24

12-24 12-25 12-26 13.

. . . . . .. . . . .. .. ... . .... . - .

MOLTEN-SALT TEST REAeTEBR MOCKUP e 13.1 INCENTIVE FOB CONSTRUCTION AND OPERATION OF REACTOR MOCKUP e e 13.2 SGrnDULE AND QUIRED FUNDING e

14.

MOLTEN-SALT

TEST

CTOR

13-1

13-1 13-1 14-1

b...

...... m ....

.... LH ...

1. PROGRAM PLAN OVERVIEW rn

p....a

....

.... ....

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1.1 INTRODUCTION AND SUMMARY Tke o b j e c t i v e of developing b r e e d e r r e a c t o r s i s t o o b t a i n a r e l i a b l e and abundant s o u r c e of energy through e f f i c i e n t u s e of our uranium and thorium r e s o u r c e s . Molten-salt b r e e d e r r e a c t o r s have a t t r i b u t e s of f u e l u t i l i z a t i o n , economics, and s a f e t y t h a t make them w e l l s u i t e d t o t h i s objective. The h i g h l y s u c c e s s f u l o p e r a t i n g e x p e r i e n c e of t h e Molten-Salt Reactor Experiment and t h e developments i n chemical processes t h a t have allowed a n important s i m p l i f i c a t i o n i n t h e b r e e d e r concept s u p p o r t t h e b e l i e f t h a t r e a c t o r s having t h e s e c h a r a c t e r i s t i c s can b e s u c c e s s f u l l y developed. Because t h e y d i f f e r i n many a s p e c t s from s o l i d - f u e l f a s t b r e e d e r r e a c t o r s , M B R s p r o v i d e good i n s u r a n c e f o r t h e n a t i o n ' s energy supplgp i n case major o b s t a c l e s are encountered by t h e o t h e r concepts. In a d d i t i o n , t h e a b i l i t y of t h e m o l t e n - s a l t r e a c t o r t o b e s t a r t e d up as a b r e e d e r o r o p e r a t e d e c o n ~ ~ ~ i c a l las g pa c o n v e r t e r on plutonium, 235U, o r 2 3 3 U makes i t p a r t i c u l a r l y s u i t a b l e as a companion f o r o t h e r t y p e s o f r e a c t o r s i n a balanced f u e l economy. It i s b e l i e v e d t h a t a s t r o n g l y motivated and a d e q u a t e l y funded program can l e a d t o m o l t e n - s a l t b r e e d e r r e a c t o r s t h a t can p l a y a major r o l e i n p r o v i d i n g f o r our f u t u r e energy needs. This program p l a n f o r t h e development of t h e molten-salt b r e e d e r r e a c t o r (MSBR) is based on two primary ground r u l e s provided by t h e AEC. F i r s t , a program w i l l b e undertaken t o r e s o l v e t h e m j o r u n c e r t a i n t i e s concerni n g t h e t e c h n i c a l f e a s i b i l i t y of m o l t e n - s a l t b r e e d e r r e a c t o r s . Then, assuming f a v o r a b l e r e s o l u t i o n of t h e e u n c e r t a i n t i e s , development w i l l proceed i n s u p p o r t of d e s i g n and c o n s t r u c t i o n of a m o l t e n - s a l t test r e a c t o r . The p l a n n i n g s t u d i e s i n d i c a t e t h a t t h e c r u c i a l problem and c r i t i c a l p a t h i t e m d u r i n g t h e f i r s t phase of t h e work i s demonstration of an a l l o y f o r t h e s t r u c t u r a l material of t h e r e a c t o r primary system. The a l l o y must have s a t i s f a c t o r y r e s i s t a n c e t o s u r f a c e c r a c k i n g when under stress i n c o n t a c t w i t h t h e f u e l s a l t i n a r e a c t o r environment, s a t i s f a c t o r y c o r r o s i o n r e s i s t a n c e i n f u e l and c o o l a n t salts, and s a t i s f a c t o r y mechanical p r o p e r t i e s o v e r t h e long-term under r e a c t o r conditions. I n a d d i t i o n t o demonstrating an a c c e p t a b l e material of c o n s t r u c t i o n f o r t h e primary c i r c u i t , i t i s d e s i r a b l e t o demonstrate, at least i n p r i n c i p l e , t h e s o l u t i o n s t o several o t h e r p r o b l e m of m o l t e n - s a l t r e a c t o r s b e f o r e proceeding w i t h c o n s t r u c t i o n of a test r e a c t o r . A method should b e demonstrated f o r p r e v e n t i n g t r i t i u m t h a t i s produced i n l a r g e q u a n t i t y i n t h e r e a c t o r f u e l from t r a n s f e r r i n g through t h e secondary c o o l a n t i n t o t h e steam system from which i t would b e r e l e a s e d t o t h e environment. Inf o r m a t i o n should b e provided t o a s s u r e t h a t sodium f l u s r o b o r a t e w i l l b e s a t i s f a c t o r y € o r u s e as t h e secondary c o o l a n t of a b r e e d e r r e a c t o r o r t h a t t h e r e is an a c c e p t a b l e a l t e r n a t e c o o l a n t . More complete i n f o r m a t i o n should b e o b t a i n e d on t h e l e v e l of o x i d e contamination i n t h e proposed f u e l s a l t t h a t would c a u s e troublesome p r e c i p i t a t i o n of uranium from t h e

1-1

lb-2

salt. sxide

The principles CsncentKatiQn

of any processes found should be demsnstrated.

necessaq

CsrttKol

t&e

ssme fUK%hE!P assurance SkcmPdbe provided %ha% raplfaite can be obtained commercially that wiP1 satisfy the tinimum requiremnts fbr the CQ%eof a large breeder reacztor. Con%inuQms m-line processing sf %ke fuel willl be necessary ts achieve a positive bpeeding gain im a mdteR-salt Peaetsr. Operatisn of the major process steps in engineering equipmen% should be dsnlonstrated. Additisnal studies sksudd be made for eertafrn as$ec%s sf the reference design MSBR in srder %o assure that: an accep%able reference design has it will be necessary ts show in a eoncep%ual been obtained. FinalPy, design that the plpopssed test reactor is feasible ts build and maintain, and that it can be expected to provide that it can be operated safely, the infsrmation needed for proceeding with a larger demnstratisn plant. It is estimated thpt with the fulzding curren%~y projected for the Mt3l%enSal.% Reactor Program these objectives can be achieved by %he end of A' Consegtualb design of a test reactor (estimated total cmst, $450 1978. million in FY 1975 dol%ars) and 8 test rextcrr mockup (estimated total ~QS%~ $50 million in FY P975 dollars) wsu%d be completed during FY H979 fm supporting requests fsr authorization of these projet2ts in FY P981. It is anticipated %ka% operation of the test reactor wsrald begin in The uperating budget for research and development WOtlPd rise l?Y 1989. frum $4 milblisn during FY 1975 to $B1 mi%lion (in EY 1975 dsllars) in If it is de%e%rained that the Program is to proceed with deFY 1378. it is estimated that increases in research velopment for a test reactor, and development: funds will. be required to a level of $13 to $19 million The actual budgets per year (in FY 1975 dsllars) for the later years. required for the years beyond FY 197 will depend s%rsng%y on the size and csmpPexity sf the test reactosp. Since these a%-e pafesenkly UnknQm, %be es%Lma%e of funds beyemd FY H979 involves large uncertainties.

In this subsection, a brief SUFIEM~~ will be given of the status of the technology and planned devekspment activities for each of the major areas of the Molten-Salt Reactor Prsgram. A mre detai%ed discussion of the status of tecbnslsgy, the deve%sgment gHana, the estimated schedule $ the key program miketones, and the funds required for maintaining the indicated schedule is given in the remainhg sections of this program pIan for each of the major program areas.

Has%ePloy N was develaped ~QP use with msltm sa%%s a% the high temperatures requited by aircraft power plants, and since it has good strength and good compatibility with fluoride salts, it: was used for construction

E-% of the 7.4-MW(t) Molten-Salt Reactor Experiment (NSRE) UhiPe t h e MSRE b e i n g built, experiments revealed t h a t t h e creep ductility sf HastelISY N is reduced by n e u t r o n i r r a d i a t i o n . his embrittlemen% i s caused by heliUIXl produced by t h e r l I d € l e U t r O n CaptU%eS i f l t h e a % h y i n CQntraSt With the embrfttlement due to void f o r m a t i o n by fast neutrons t h a t has been of concern f o r f a s t r e a c t o r s . Analyses showed that t h e stresses in t h e NSWE would b e s u f f i c i e n t l y l o w f o r the r e a c t o r t o b e operateel s a f e l y in spite of d e c r e a ~ e dd u c t i l i t y , b u t t h i s w i l l n o t necessarily b e true of f u t u r e r e a c t o r s , and a development program w a s begun for f i n d i n g a s o l u t i o n to the embrittlement probPew. The approach followed w a s that of a d d i n g carbide-forming elements which have been used t o a m e l i o r a t e t h e e m b r i t t l e r~ent:of s t a i n l e s s steel by fast neutroms, and 0.5 wt2 Ti was found t o S u . S L 3 h t h e d U C t i l i t y Q f %iESteiblOy N at t h e operating teEn&3&?PatUPe of $200"P. At l308"P, the outlet te e r a t u r e of t h e r e f e r e n c e design MSBR, s o l ~ t i ~ofn the c a r b i d e s i n t h e a l l o y caused the remedy t o be l o s t , but this w a s ove~comeby raising t h e titanium content t o about 2%. Some a i n was made by adding niobium with the t i t a n i u m , and hafnium i n conjunction with t i t a n i u m was found t o be very e f f e c t i v e . However, higher ~~t~ and problems w i t h weidability decreased t h e d e s i r a b i l i t y of hafnium-containing a l l o y s . e

WELS

Small c s m e r c i a l heats (I00 I b ) of 2%-Ti-modified Hastelbloy N obtained from three VendoPS W e % @ fQund t Q %lavem h i l I l u I l l Creep ductilities t h a t w e r e g r e a t e r than 4% a t 1400°F a f t e r i r r a d i a t i o n , which appears t o be adequate. The material i s f a b r i c a b l e i n t o small t u b e s and weldable under h i g h r e s t r a i n t ; hence a s o l u t i o n t o t h e enabrittkement problem appears to have been found. E x t e n s i v e n a t u r a l - and f o r c e d - c i r c u l a t i o n I Q Qtests, ~ as well as o p e r a t i o n sf the MSRE, have shorn that t h e generalized c o r r o s i o n rate of HasteEls-y N in f u e l salt i s very POW; however, examination of specimens from the MSRE i n d i c a t e d t h a t s t a n d a r d H a s t e l l o y M i s subject to i n t e r g r a n u l a r attack by t h e f i s s i o n product t e l l u r i m . Subsequent tests showed that a nu materials are n o t a t t a c k e d by t e l l u r i u m , and among them are m o d i f i c a t i o n s of Hastellsy N. The 2Z-Ti-m~diffed Hastelloy N is observed to have increased r e s i s t a n c e t o t e l l i u ~ i u r na t t a c k , and the addition of small E I ~ Q I B I ~ S of are earths or niobium has been observed t o p r e v e n t tePlurium==indnced i n t e r g r a n u l a r attack.

,.:&

1-4 c a r r i e d o u t f o r demonstrating t h e a c c e p t a b i l i t y of t h e material f o r use i n t h e primary c i r c u i t of an MSBR. The d a t a t h u s o b t a i n e d w i l l . s e n e as the basis for p r e p a r a t i o n and submission of a code case f o r t h e use of modified H a s t e l l o y p% i n t h e MSBR p r h a r y c i r c u i t . Subsequent work on t h e development of materids f o r t h e primary and s e ~ o ~ d a a scyi r c u i t s of m o l t e n - s d t r e a c t o r s w i l l b e concerned w i t h o b t a i n i n g long-term material test d a t a and f o r f u r t h e r o p t i m i z a t i o n of t h e a l l o y composition in o r d e r t o f u r t h e r improve i t s materials p r o p e r t i e s .

1 2.2 D

Fuel p r o c e s s i n g

Operation of a molten-salt reactor as a high performance b r e e d e r i s made p o s s i b l e by t h e continuous p r o c e s s i n g of t h e f u e l s a l t i n a f a c i l i t y t h a t i s l o c a t e d a t t h e r e a c t o r s i t e . A s o u t l i n e d i n Section 3 , t h e most imp o r t a n t p r o c e s s i n g o p e r a t i o n s c o n s i s t i n removing t h e f i s s i o n produets ( g r i n c i p a ~ l yt h e rare earths) and i s o l a t i n g 233Pa from the r e g i o n OB high neutron f l u x d u r i n g i t s decay t o 23% i n o ~ d e rt o h o l d n e u t r o n a b s o r p t i o n i n t h e s e materials t o a c c e p t a b l y l a w levels. It i s a l s o n e c e s s a r y t h a t excess uranium produced i n the system b e I - ~ I I I ~ fVo ~r ~sale, t h a t t h e f u e l s a l t be. maintained a t the p r o p e r redox p o t e n t i a l , and t h a t o x i d e and C S P P S S ~ S R p ~ o d ~ i~n t t h s e s a l t b e maintained a t t o l e r a b l e levels. P r o c e s s i n g of MSBR f u e l s a l t i s based p r i n c i p a l l y on t h r e e t y p e s of opera t i o n s : rmoval Of u r a n i m from t h e s a l t by f l t l o r i n a t i o n ; s e l e c t i v e removal of p r o t a c t i n i u m , rare e a r t h s , and o t h e r f i s s i o n products from t h e salt by e x t r a c t i o n into molten bismuth; and the hydrogen-reduction of UFg t o UF4 i n t h e p r e s e n ~ eof t h e processed f u e l carrier salt. In addit i o n t o these o p e r a t i o n s , t h e r e i s t h e n e c e s s i t y for a u x i l i a r y s u p p o r t s y s t e m and o p e r a t i o n s r e q u i r e d f a r close-coupled fuel p r o c e s s i n g . B e chemical basis on which t h e p r o c e s s i n g system i s founded i s w e l l

e s t a b l i s h e d ; however, o n l y small e n g i n e e r i n g experiments have been carried o u t to d a t e , a d a c o n s i d e r a b l e e n g i n e e r i n g development e f f o r t remains. During t h e period ?7Y 1975 - FY 1978, engineering expe~iments w i l l be c a r ~ i e dsup: f o r demonstrating the i n d i v i d u a l p r o c e s s i n g s t e p s on a scale t h a t ranges from 5 t o 50% of t h a t r e q u i r e d f o r p r o c e s s i n g a 1000-P16d(e) MSBR. This work w i l l b e c a r r i e d o u t i n t h e h i g h bay area b u i l d i n g (Bldg. 7503) where a d e q u a t e s p a c e i s a v a i l a b l e . Subsequent work on f u e l p r o c e s s i n g w i l l r e q u i r e t h e c o n s t r u c t i o n of a new b u i l d i n g ( t h e ESBR P r o c e s s i n g Engineering Laboratory) i n which t h e simultaneous o p e r a t i o n of two or more p r o c e s s s t e p s w i l l b e s t u d i e d and a d d i t i o n a l development work c a r r i e d o u t . A u t h o r i z a t i o n f o r t h i s facility, which i s e s t i m a t e d t o c o s t $12 m i l l i o n , i s r e q u i r e d e a r l y i n FY 19TT. Subsequent t o completion of e n g i n e e r i n g experiments d e a l i n g w i t h a s i n g l e p r o c e s s opehation, a system ( t h e I n t e g r a t e d Process T e s t F a c i l i t y ) w i l l be c o n s t r u c t e d f o r the n o n r a d i o a c t i v e demonstration o f p r o c e s s e s and equipment f o r f u e l p r o c e s s i n g a t t h e p i l o t p l a n t l e v e l . This f a c i l i t y w i l l b e used t o c t a ~ n s t r a t et h e s a f e t y and performance r e l i a b i l i t y o f p r o c e s s i n g systems, to p r o v i d e i n f o r m a t i o n f o r development of maintenance methods, and t o p r o v i d e a b a s i s f o r e v a l u a t i o n of

h..

1-5 continuous o n - s i t e processing; of MSBR f u e l s a l t . S u f f i c i e n t i n f o r m a t i o n w i l l r e s u l t from o p e r a t i o n of t h i s and earlier e n g i n e e r i n g s y s t e m t o a l l o w d e t a i l e d d e s i g n o f a p r o c e s s i n g p l a n t for a test r e a c t o r and comp l e t i o n of c o n c e p t u a l d e s i g n s t u d i e s f o r t h e r e f e r e n c e desfgn MSBR.

... @ a

The a c t i n i d e s c o n s t i t u t e a l ~ ~ ~ g - t ewaste rm hazard f o r a l l n u c l e a r power r e a c t o r s , and i t i s d e s i r a b l e t o devekop means f o r r e c y c l i n g t h o s e produced i n an MSBR t o t h e r e a c t o r f o r t r a n s f o r m a t i o n t o less u n d e s i r a b l e isotopes v i a transmutation and/or f i s s i o n . Studies w i l l be c a r r i e d out d u r i n g t h e e a r l y phases of work ow f u e l p r o c e s s i n g in o r d e r t o d e t e r n i n e t h e p o t e n t i a l f o r a t t a i n i n g a c t i n i d e separatforn and r e c y c l e i n an MSBR and f o r t h e development of f l o w s h e e t s and equipment n e c e s s a r y f o r e f f e c t i n g this r e s u l t . 1.2.3

&el

p r o c e s s i n g materials development

The materials requirements f o r MSBR f u e l p r o c e s s i n g systems a r e dependent upon t h e p r o c e s s i n g methods u t i l i z e d and t h e d e s i g n of p a r t i c u l a r equipment i t a s s e l e c t e d f o r e f f e c t i n g t h e s e p r o c e s s i n g s t e p s . At t h i s t i m e , s t u d i e s aimed a t f i n a l s e l e c t i o n ~f p r o c e s s i n g s t e p s are b e i n g completed; hence, d e s i g n of t h e p r o c e s s i n g p l a n t equipment has n o t been c a r r i e d o u t . P r o c e s s e s i n v o l v i n g removal of uranium from f u e l s a l t by f l u o r i n a t i o n and seheetive e x t r a c t i o n of p r o t a c t i n i u m and f i s s i o n p r o d u c t s f ~ o mfuel s a l t i n t o l i q u i d bismuth are considered t h e most proraising methods availa b l e , and t h e c u r r e n t p r o c e s s i n g materials program is o r i e n t e d i n t h i s direction e

.... ..... :::*

It i s n o t n e c e s s a r y t h a t a s i n g l e material b e compatible w i t h a l l environments a n t i c i p a t e d i n t h e p r o c e s s i n g p l a n t s i n c e t h e system can b e designed t o a l l o w s e g r e g a t i o n of p a r t i c u l a r p o r t i o n s sf t h e p l a n t . It i s expected t h a t a t least t w o classes o f materials w i l l b e r e q u i r e d : one f o r the fPuorPnati~nand f u e l r e c o n s t i t u t i o n s t e p s and a n o t h e r f o r t h e r e d u c t i v e e x t r a c t i o n s t e p s . Nickel o r it nickel-based a l l o y , which i n some cases must b e p r o t e c t e d from c o r r o s i o n by a Layer o f f r o z e n s a l t , c a n b e used f o r c o n s t r u c t i o n of f l u o r i n a t o r s , and f o r those p o r t i o n s of a p l a n t which c o n t a i n f l u o r i n e , UF6, and HF. The c ~ r r o s i o nof n i c k e l and nickel-based a l l o y s d u r i n g f l u o r i n a t i o n o p e r a t i o n s h a s been e v a l u a t e d e x t e n s i v e l y a t QmL. Much of t h e i n f o r m a t i o n has evolved from f u e l r e c o v e r y o p e r a t i o n s conducted with molten f l u o r i d e w i x t u ~ e su s i n g i r r a d i a t e d m e t a l l i c f u e l elements. These d a t a afford u s e f u l g u i d e l i n e s and b a ~ l s g r o ~ nidn f o r m a t i o n f o r t h e s e l e c t i o n of materials for t h e proposed f l u o r i n a t i o n and recons t i t u t i o n s t e p s , b u t show t h e importance of i n e r t i n g t h e metal s u r f a c e s i n f l u o r i n a t i o n s y s t e m w i t h a p a s s i v e f r o z e n s a l t l a y e r . In a d d i t i o n t o c o m p a t i b i l i t y e v a l u a t i o n s , many y e a r s of e x p e r i e n c e have been accumul a t e d i n t h e f a b r i c a t i o n and j o i n i n g of t h i s class of materials stemming from the c o n s t r u c t i o n of r e a c t o r s and a s s o c i a t e d hardware as w e l l as f l u o r i d e - s a l t p u r i f i c a t i o n equipment. Hence, v e r y Little r e s e a r c h and development work of a materials n a t u r e w i l l b e r e q u i r e d for those p o r t i o n s of t h e p r o c e s s i n g system t h a t are f a b r i c a t e d from n i c k e l o r nickel-based alloys e

o has e x c ~ e l l e n t resistance ~ t~ o corrosion ~ by bismuth e ~ I t e n - f l u o r i d e TEixtures, the use of moly urn as a strucl y specialized assedlg p ures and imposes s t r i n g e n t limitations on equsipmewt des n f r o m t h e s t a n d p o i n t s of: geometry and rigidity vera% advances in m o l denun fabrication t e c h n i q u e s have helirarrz leak-tf n m welds have been gsten-arc techniques, the d u c t i l e - b r i t t l e t r a n s i t i o n Of the result iS above KBOTL1 ternp e r a t u s e . Henee, each j o i n t must b e careful support the r e s u l t i n g w e l d s . The r e s u l t s o ate on mlybdenum a believed that f ab r aH cation techniques have been en co uragin t h e material can be used in c o n s t r u c t i n g s m a l l components for p r o c e s s i n g system if p r o p e r a t t e n t i o n i s given t o i t a f a b r i c a t i o n c h a r a c t e r i s t f s s .

Although ~ solutions o r

In c o n t r a s t t o mC3lybdenum9 t a n t m o r the t a n t a l u m a l l o y T-11% i s quite d u c t i l e in t h e as-welded C o n d i t i o n , and SeVeKal cOElpb2X a s S @ d l f @ S have been f a b r i c a t e d a t OK% u s i n T-%LP. The r e s i s t a n c e of t h i s a l l o y t o c a r r o s i s n by bismuth salutions a t 700" is actequate; howeverBT, i t s resistance t o c o r r o s i o n by NSBR f u e l carrier s a l t i s unknown and is c o n s i d e r e d r g i n a l from themadynamic c o n s i d e r a t i o n s . However, tantaliurn would w i t h k t e n L i e 1 which i s p r e s e n t i n B o r n e p o r t i o n s Tantalumu, o r T - 1 % l , would r e q u i r e a h i g h e r p r o t e e t i o n from i n t e r s t i t i a l i m p u r i t i e s ( 0 , e , N) than would m l y b d e a m . Graphite, which has e x c e l l e n t c o m p a t i b i l i t y w i t h fuel s a l t , a l s o shows p r o d s e f o r c o n t a i n i n bismuth solutions. T e s t e have shewn no evidence sf c h e ~ e a il n t e r a c t i bemeen g r a p h i t e and bismuth containing up t o 58 a t . X l i t h i u m a t TQB"C, a l t h s u est pores of c o m e r e i a l l y r a p h i t e %LKE p e n e t r a t e d t o some e x t e n t by bismuth s o l u t i o n s . ved that the extent of p e n e t r a t i o n can b e reduced t o t o l e r a b l e levels by the use of e s t a b l i s h e d s u r f a c e - s e a l i n g techniques. Some WOK^ on graphite-toraphite-to-metal joists ill b e required e

It i s expected t h a t a combination of h a p h i t e , m o i y b ~ ~ n mana , perhaps tantalum will be use i n t h o s e p o r t i o n s sf f u e l p r o c e s s i n g s y s t e m that contain bismuth. Ak o r a ! & t a n t d m a l l o y s present f e w e n g i n e e r i n g developmental p r o lem, it is e ected that compatibility with mo3bten fluorides and suseept e n v ~ r ~ ~ e~o n~t ann ta tai o~n m y limit t h e i r w e . Prom an e ing p o i n t 0% view the m e sf g r a p h i t e w%EP r e q u i r e less ~ e v e l o ~ m ework n ~ than ana therefore ~~~~~~~

1-7

will be p l a c e d sn s t u d i e s of r a p h i t e for the near tern. The work t o be UndeKtaken i n Eke lollger t m, however, a l l o w s f o r a d d i t i o n a l development of t h e s e materials f o r more extensive p r o c e s s i n g p l a n t a p csti~lils EJear-tem c o m p a t i b i l i t p r e s u l t s and f u e l p r ~ c e s s i n gf l ~ ~ h e e t developments will dictate the extent to which subsequent work w i l l b e undertaken ~ O Keach sf t h e materials. e

A s outlined i n S e c t i o n 4 , work % s i l l b e carried orat initially t o thoroughly i n v e s t i g a t e t h e che sal c o m p a t i b i l i t y of p o t e n t i a l c o n t a i n e r W i t h fuel prQceSSi system environments under simulated prsce ditions The WO& will include i n v e s t i g a t i o n s o f the chemical e s m p a ~ i b i l i t y of g r a p h i t e and t a n t a l u m w i t h bismuth solutions and molten-salt aixtkares as well as compatibility of s u i t a b l e b r a z e alloys w i t h t h e s e s o l u t i o n s . The work will i n v o l v e a umber of c a p s u l e and thermal convection l o o p tests, as w e l l as the o eratisn of a g r a p h i t e forC@d-ConVeC$ion loop f o r Study O f g r a p h i t e CQ rosion in t h e presence of v e l o c i t y and temperature g r a d i e n t s I f g r a p h i t is to b e una c c e p t a b l e for u s e i n p r o c e s s i n g p l a n t a p p l i c a t i o n s , i t m y be necessary ts o p e r a t e a d d i t i o n a l forced convection l o o p s that are c o n s t r u c t e d of tantalum. e

~~~~~~~~~

Upon completion o f the compatibility studies, t h e second phase of the work will be undertaken which involves t h e ~ ~ ~ e l of o ~t h e~ required ~ n t fat3 r i c a t i s n and js i n i n techniques $08 materials w b s e compatibility has been demonstrated. For example, the j o i n i n phite w i l l be studied by the techniques of b r a z i n g , adhesive bond temperature d i f f u s i o n bOXldhg, and t h e US'S O f meChaniCd g Q i n t S . ent t o which fabrlcadenram ana tantalum t i s n and joining techniques w i l l b e s t u d i e d a p h i t e as a material a l l o y s w i l l b e dependent upon t h e aceeptabil O f construction.

me t k i r a phase of the p r ~ o ~ e s s i nmg t e ~ i a l s~ e v a c t i~v i t y ~w i i a ~inv o l v e assistance d u r i n g ~ ~ p a ~ t r ~and ~ t oi poenr a t i o n of en m n t s ow fuel processing. Erafoegnation on materi and c o n s t r u c t i o n of experimental system will b e d , and a surveillance program will e carrFed a u t t o evaluate the effect of fuel processi n g o p e r a t i o n s on t e r i a l s properties e

1.2.4

1-8

based on a long, w e l l e s t a b l i s h e d background of e x p e r i e n c e and appears q u i t e l i k e l y to m e e t t h e requirements of K S B b w i t h a minimraw s f addit i o n a l r e s e a r c h and development. Previous work w i t h c o o l a n t s a l t s h a s been much mre limited t h a n t h a t w i t h f u e l salts. The c o o l a n t salt for t h e Molten-Salt R e a c t o r E ~ p e ~ i m e k l t , a LiF-BeF2 m i x t u r e , w a s used t 5 reject h e a t t o an a i r r a d i a t o r . ?he m e l t i n g p o i n t of t h e m i x t u r e i s h i g h e r than i s a c c e p t a b l e f o r u s e w i t h a conventional. steam system. The use of sodium f l u o r o b o r a t e as a c o o l a n t w a s f i r s t suggested i n 1966 and e x p e r i e n c e w i t h this s a l t has beem accumulated s i n c e t h a t t i m e . Considerable a d d i t i o n a l r e s e a r c h i s needed t o a s s u r e t h a t the s a l t will b e a s a t i s f a c t ~ qe o s l m t . The s a l t i s mre c o r r o s i v e toward Hastellboy N than i s t h e f u e l s a l t , and a d d i t i o n a l knowledge of c o r r o s i o n r e a c t i o n s i s r e q u i r e d . I n t e r a c t i o n s of the c o o l a n t with fuel salt a d with steam, which could r e s u l t from s t e m g e n e r a t o r l e a k s , need to b e mare fully c o n s i d e r e d , and a d d i t i o n a l m a s u r e m e n t s o f p h y s i c a l p r o p e r t i e s are needed. Although f l u o r o b o r a t e can p o s s i b l y b e used as t h e c o o l a n t s a l t f o r MSBRs, t h e r e i s i n c e n t i v e t o c o n s i d e r a l t e r n a t i v e c o o l a n t materials and e v a l u a t i o n o f a l t e r n a t e coolants w i l l receive e a r l y a t t e n t i o n i n addition to r e s e a r c h and devekqxi~enton f l u o r o b o r a t e . The o b j e c t i v e of WOK^ o u t l i n e d i n S e c t i o n 5 i s to o b t a i n t h e chemical tion necessav f o r t h e d e s i g n of m o l t e n - s a l t b r e e d e r r e a c t o r s . Work i n t h e a c t i v i t y will include s t u d i e s of f u e l and c o o l a n t salt chemistry, ~ ~ e a ~ u ~ of e ~t h~e er en qtu i r e d p h y s i c a l p r ~ p e r t i e s ,s t u d i e s r e l a t i n g t o t r i t i u m management and t h e d e l i n e a t i o n of o p e r a t i n g parameters, and chemical s t u d i e s r e l a t e d t o o f f - d e s i g n e v e n t s such as temperature exc u r s i o n or Peaks. Laboratory-scale s t u d i e s will be c a r r i e d o u t which w i l l i n v o l v e d e t a i l e d i n v e s t i g a t i o n s of t h e chemistry of E B R f u e l salt i n c l u d i n g measurement of s o l u b i l i t y p r ~ d u s t sf o r t h e actinaide o x i d e s , studies of t h e ~ ~ P u t i o n behavior of tellaartum under various redox c o n d i t i o n s , phase b e h a v i o r of PaaFg, f u e l - c o o l a n t i n t e r a c t i o n s , and d e t e r m i n a t i o n of p h y s i c a l p r o p e r t y aata. siwiiariy, understanding of t h e c h e ~ s t vof the coolant salt must b e greatly enhanced. Oxide and hydroxide shemistpy i n f l u o m b o r a t e w i l l r e c e i v e i n t e n s i v e s t u d y along w i t h i n v e s t i g a t i o n s of t h e c ~ r r o s i o n c h e d s t r y of this salt, methods f o r p u r i f y i n g t h e s a l t , and wasuremenats sf p h y s i c a l p r o p e r t i e s . An assessment of a l t e r n a t e coolants w i l l b e ....

T r i t i u m b e h a v i o r i n PGBW systems w i l l a l s o r e q u i r e a major e f f o r t . In a d d i t i o n to measurements of t h e p e r m e a b i l i t y of V~KIOUS alloys t o tritim,

t h e p o s s i b i l i t y of s u s t a i n i n g an impermeable o x i d e f i l m on t h e s t e m side of steam g e n e r a t o r tubes w i l l b e f u l l y explored. Wasurements of t h e s o l u b i l i t i e s , d i f f u s i v i t i e s , e t c . of tritium and HT i n f u e l and coalant salts w i l l b e made t o a i d h p r e d i c t i n g tritium b e h a v i o r i n MSBR s y s t e m . S t u d i e s of f i s s i o n product chemistry w i l l b e focused c h i e f l y on the chemistry of niobium, l y b d e n m , and o t h e r noble metals, and i o d i n e i n o r d e r t o a l l 5 w t h e a c c u r a t e p r e d i c t i o n of fission product d i s t r i b u t i o n

k...i.

,..... .-

1-9 i n an MSBR. Fundamental s t u d i e s o f LiF-BeP2-ThF4 mixtures w i l l i n c l u d e d e t e r m i n a t i o n of a c t i v i t y c o e f f i c i e n t s of b o t h major a d I I I ~ W O P components o f t h a t system. Porous e l e c t r o d e s w i l l b e used t o s t u d y t h e chemistry of trace elements such as bismuth i n MSBR f u e l s a l t .

B 2.5 a

... . :.a :\

,:&

h a l y t ical r e s e a r c h and development

S u b s t a n t i a l e x p e r i e n c e i n t h e h a n d l i n g and a n a l y s i s of n o n r a d i o a c t i v e f l u o r i d e Iltelts w a s gained i n t h e A i r c r a f t Nuclear BropuPsion Program. Methods w e r e developed f o r a n a l y s i s of m o s t c a t i o m i c c o n s t i t u e n t s of i n t e r e s t as w e l l as for f l u o r i d e and v a r i o u s forms sf s u l f u r . Applicat i o n of t h e s e t e c h n i q u e s t o t h e a n a l y s i s of r a d i o a c t i v e samples from t h e Molten-Salt Reactor Experiment r e q u i r e d a d a p t a t i o n of t h e methods t o remote, h o t - c e l l o p e r a t i o n s . More r e c e n t l y , t h e development of improved a n a l y s i s methods f o r d i s c r e t e samples has continued as w e l l as t h e i n c o r p o r a t i o n of a v a r i e t y of improved i n s t r u m e n t a l methods as t h e y have become a v a i l a b l e . Operation of an HSBR w i l l r e q u i r e t h a t adequate ~ u ~ ~ e i l l bae ~m~i nc t ea t n e d The more c r i t i c a l determin a t i o n s are m e n a b l e t o i n - l i n e measurement, and f a c t o r s such as t i m e , c o s t , and d i f f i c u l t y of a n a l y s i s by t h e d i s c ~ e t e - s m p l eapproach a r g u e s t r o n g l y t h a t i n - l i n e t e c h n i q u e s be developed when practi~al. There i s also t h e n e c e s s i t y for development of i n - l i n e and s p e c i a l a n a l y t i c a l techniques as r e q u i r e d d u r i n g t h e technology development a c t i v i t i e s of t h e Program. It is a n t i c i p a t e d t h a t t h e development of a n a l y t i c a l techniques r e q u i r e d f o r t h e technology phase of t h e P K O ~ Kw ~i lI l ~ r~e s u l t i n an adequate b a s e f o r f u r t h e r development as r e q u i r e d by t e s t and demonstration reactors. ow t h e composition sf v a r i o u s r e a c t o r streams.

.;%

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...

... ....

. . . 7.8 . . y

For t h e a n a l y s i s of molten-salt streams, e l e c t r o a n a l y t i c a l t e c h n i q u e s such as v o l t a m t r y and p o t e n t i s m e t r y appear t o o f f e r t h e most convenient t r a n s d u c e r s f o r remote i n - l i n e measurements. For example, d e t e r m i n a t i o n of t h e redox p o t e n t i a l of MSBR f u e l s a l t , as i n d i c a t e d by t h e U3+/U4+ r a t i o , as well as t h e c o n c e n t r a t i o n of ~ ~ K % Q S ~ C pX rI o d u c t Cr2*, has been made on a completely automated b a s i s over a p e r i o d of several months i n thermal- and forced-convection t e s t l o o p s . Other i m p o r t a n t a n a l y t i c a l t e c h n i q u e s i n c l u d e s p e c t r o p h o t o m e t r i c methods for both s a l t and gas streams, and t h e u s e of t r a n s p i r a t i o n methods whereby t h e composition of a m o l t e n - s a l t phase i s i n f e r r e d by a n a l y s i s of a gas stream which has been e q u i l i b r a t e d w i t h t h e s a l t . The work o u t l i n e d i n S e c t i o n 6 a l l m s for t h e development of d e v i c e s which show promise f o r i n - l i n e a p p l i c a t i o n s as r e q u i r e d d u r i n g t h e development of %BR technology as w e l l as t h e o p e r a t i o n of test and d e m s n s t r a t i o n r e a c t o r s . C h a r a c t e r i s t i c a l l y , development of a p a r t i c u l a r i n - l i n e anal y t i c a l d e v i c e w i l l b e c o n c e n t r a t e d i n i t i a l l y on t h e a c q u i s i t i o n of b a s i c i n f o r m a t i o n u n d e r l y i n g o p e r a t i o n of t h e d e v i c e . There w i l l t h e n f o l l o w t h e t e s t i n g of p r o t o t y p i c d e v i c e s i n n o n r a d i o a c t i v e systems.

....

1-10 Finally, those evfces which show pr er a n d i t i o n s s

se f o r reactor applications w i l l

t o r en%siranmnt of r a d i a t i o n da

.... ,.....

c t o r teet-nwolo eneral, and t h e work in i r e r a f t Nuclear P r o s i o n atad X o l t Reactor Program at o m have p r o d d e d muc Of the i n f o r m t i o n required t o demnstrate t h e safety of molten-salt re ctsrs. None sf the work has i n d i c a t e d safety issues that cannot be re oPved with e x i s t h g technolo the issues t are s p e c i f i c to t h i s reactor esneept have eted to the c rehensive analysis and assesswnt that have 8 other reactor concepts. onsequentlg, some additiomlb is required to de strate clearly the safety of ces in the area sf

cB less i n t e n 88

of fuel salt. ... c,.x.

As o u t l h e d in Section $ $ s t u

o f less concern,

e area of reactor safety wilf

1-11 t h a t the mre nor 1 operations sf a plant define system conditions t h a t be ag-fe,tea b accidents, some consideration m u s t a l s o be given to nor& plant behavior. E x i s t i n g safety and safety-related technolo developed e i t h e r within t h e m ~ t e n - s a ~~te a c t o rprogram or w i t h i n o s t i c or f o r e i reactor safety progr w i l l be assessed, adapted as IpeqUiIped, and adspted for aQQ6ECatiOn to the afety effort &enever such adoptions are consistent with the overall p r o ram objectives. Additional safety technsls WLll be developed only when unique, specified needs are identified.

Over the past twenty years, several Iten-salt reactor p l a n t s have ed conceptually, two e q e r b e n t a l molten-salt reactors were and operated a t 8 The hhircraft &%WtoK E nt, which sperated briefly in 1 9 5 4 , demnstrated the basic reactor concept; h O w e V e b , since the rl&.3sion of that project was n o t central-station power generat % O f z , the KeaCtor lackEd features that are i m p o r t a t for Iar breeder reactors. During the Inid 19608s the rnLten-Salt was operated f o r extended period and yielded much val which power reaet concepts could be based. This sysee ge?XHalPy s i d . h r to that prC%pO§edfob the breeder, aA mderator, a secondaq coolant s a l t circuit, and a structuraB alloy of interest to the breeder concept. ....A

.... *&

....

*Z&

... ... .:&

Two basis breeder concepts have been. studied: the first of these i.nw%ved m radioactive primary coolant a f i s s i l e stream of urani and l i t h i m flmrides, and a co egefgP SepalX%$ebh9aket oL^ fertile Sa%$ o f tharim, %itUw,and b e q l l flwrides. This system appeared ts excellent breedin @e* and a relatively s i m p l e f u e l procplant; however, separation of the two f l u i d s via te tubes in t h e c d be difficult in view of t h e %If changes which occur in graphite d irradiation. De 2n the area of e h e d e a l processin t f o n of alternaee possibilities l e a d to the single-fluid concept Ln which both t h e fertile and f i s s i l terlals are dissolved in the sa pr-q salt.

For the past several y e a r s , the

... ....

effort has bee diKeCted toward the Shgbe-ffui %eaturesa s i n reactor vessel and four p at circulate f U @ l between BntermdLate heat excha s me reactor vessel contains maelad graphite to provide neutron ~ ~ ~ l e ~ina three t i ~ n recoaizable zones consisting of the corep the blanket, m d the reflector. me fuel salt c f r c d a t e s through the three zones, which are not physically isolated from each other, me different neutronic effects in t h e zones B F B aChiesPed refully &electing t fuel-to-moderator r a t i o for each zone. Each p loop contains eq wt for helium injection ofad some fuel salt is e

.... S&

....

d sther wlaeile specfes. emeen t h e drain tank 8n

1-12 priraary loops i n order t o c o o l p o r t i o n s of major components and t h e offgas st~ean. The d r a i n tank p r o d d e s t h e i n i t i a l holdup f o r decay of f i s s i o n - p r o d u e t gases as w e l l as a f t e r h e a t removal c a p a b i l i t y if t h e f u e l s a l t m u s t b e d r a i n e d from t h e prilllitry c i r c u i t . Beyond t h e primary system, t h e r e are no major d i f f e r e n c e s between t h e A secondary s a l t , sodium fluaroborate, t r a n s p o r t s t h e f i s s i o n energy from each i n t e r m e d i a t e h e a t exchanger t o a s t e a m g e n e r a t o r , which i s coupled t o a ~ r e - o r - l e s s conv e n t i o n a l s u p e r c r i t i c a l steam system h a : g e n e r a t i o n of e l e c t r i c i t y .

one-fluid and t h e o l d e r , two-fluid concepts.

Although t h e basic r e a c t o ~concept i s r e a s o n a b l y w e l l e s t a b l i s h e d , t h e r e er of aspects that have not y e t been s t u d i e d i n s u f f i c i e n t d e t a i l t o r e s o l v e a l l p o t e n t i a l q u e s t i o n s . These i n c l u d e the l a y o u t and d e s i g n of a l l major parts of the primary system. I n p a r t i c u l a r , a d d i t i o n a l stress a n a l y s i s work i s r e q u i r e d t o show t h a t o~cl%aaa~y mechanical as w e l l as thermal stresses throughout the system are compatible w i t h d e s i g n and life requirements f o r a l l c o n d i t i o n s .

The p h y s i c a l arrangement of t h e g r a p h i t e i n s i d e t h e reactor vessel is i m p o r t a n t in d e t e d w i n g the performnee of the systeme S i n c e g r a p h i t e dimensional changes are an e f f e c t of n e u t r o n i r r a d i a t i o n , t h e core must be designed t o accomodate such changes w i t h o u t unacceptably degrading the r e a c t o r p e r f o r m e e . A l s o , the g r a p h i t e arrangement must a l l o w for periodic replacement of a t least some of t h e mderator. A d d i t i o n a l work is r e q u i r e d to ensure that r a d i a t i o n heating i s a p p r ~ p r i a t e l yhandled in the reference * All of the primary-system eo onents w i t h i n the primary contai must be p h y s i c a l l y s u p p o r t e d i n way such as t o a c e o m d a t e thermal expansion e f f e c t s and major d i s t u r b a n c e s such as earthqmkes w i t h o u t l o s s of i n t e g r i t y . Comercial-scale BE& wLl1 be deaf ed mechanically for a useful life as hi@ as 1300°F w i t h numerous t h e ~ m l of 30 years a t t e q e r a t u r cycles; however, the d e s i p r e s s u r e i s r e l a t i v e l y l o w . Much of the techt h a t is being deve ped for sther reactor concepts w i l l be a p p l i cable o r at least a d a p t a b l e t o BR d e s i g n p r o b l e m ; however, t h e sta:uctaaral material for t h e NSBR p r i E-y c i r c u i t (Hastelloy N) has d i f f e r e n t c h a r a c t e r i s t i c s than materials t h a t are b e i n g developed p h y s i c a l and a g i f o r o t h e r high-t f o r e 9 considerabPe e f f o r t k6.11 be r e q u i r e a p p l i c a b i l i t y o f , and a p p l y appPOpKhte des C a p i t a l cost studies on molten-salt r e a c t o r plants have been made i n r e c e n t years by 0 as w e l l as s e v e r a l independent organizations. The conclusisns from t h e s e s t u d i e s are that MSBBs a p p e a r t o be e e o n o d c a l l y attractive i n the U.S. power economy. Each of the s t u d i e s was necessart e d i n precisfon by t h e s t a t e of develop nt of t h e c o n c e p t u a l a t was s d j e c t e d t o analysis, and such mitations w i l l contin=

t a i n t y can be ected t o diminish t h e r e a c t o r design evolves. Thus, c a p i t a l costs o t h e r a s p e c t s of BR e c o n s d c s w i l l be f r e q u e n t l y reassessed to a s u r e that c%esisandi develop=nt e f f o r t s BPB being a p p i i e a t o systems t h a t are, i n fact, attractive.

h. I

.... & !a

1-13 F i n a l l y , an important a s p e c t of t h e c a p i t a l and o p e r a t i n g c o s t assessments f o r m o l t e n - s a l t r e a c t ~ r si s determining the impact t h a t v a r i o u s d e s i g n o p t i o n s have on o v e r a l l costs. The r e f e r e n c e MSBW u s e s a p a r t i c u l a r d e s i g n c o n f i g u r a t i o n , a p a r t i c u l a r secondary c o o l a n t , and a p a r t i c u l a r stearn c y c l e . Various a l t e r n a t i v e s have been and wibk c o n t i n u e t o be advanced from t i m e t o t i m e i n c l u d i n g c o n v e r t e r and simple burner r e a ~ t o ~ ~ , smaller o r multi-use r e a c t o r s , alternate secondary c o o l a n t s and c o o l a n t c i r c u i t c ~ n f i g ~ r a t i o n sand , a l t e r n a t e steam c y c l e s . The ~ C O ~ Q I I eEf~f e c t s of such a l t e r n a t i v e s , s i n g u l a r l y and i n v a r i o u s co i n a t i o n s w i l l be examined t o p r o v i d e a sound b a s i s f o r choosing t h e most d e s i r a b l e system(s) to b e developed.

....

:;.... &

1.2.8

G r a p h i t e development

The g r a p h i t e i n a s i n g l e - f l u i d MSBR s e ~ v e sn8 s t r u c t u r a l purpose o t h e r than t o d e f i n e t h e flow p a t t e r n s of the salt i n the r e a c t o r c o r e and, of course, t o s u p p o r t t h e f o r c e s r e s u l t i n g from i t s own w e i g h t and momentum t r a n s f e r from t h e flowing s a l t . The requirements on t h e material. are d i c t a t e d most s t r o n g l y by n u c l e a r c o n s i d e r a t i o n s , namely s t a b i l i t y of t h e material a g a i n s t radiation-induced d i s t o r t i o n , n o n p e n e t r a b i l i t y of t h e f u e l - b e a r i n g m ~ l t e ns a l t , and nonabsorption of xenon into t h e g r a p h i t e . The p r a c t i c a l l i m i t a t i o n s i n meeting t h e s e requirements i n t u ~ nimpose c o n d i t i o n s on t h e core d e s i g n , s p e c i f i c a l l y tlae n e c e s s i t y t o provide f o r p e r i o d i c g r a p h i t e replacement and t o limit: t h e c r o s s s e c t i o n a l area of t h e g r a p h i t e prisms.

The g r a p h i t e p r e s e n t i n t h e Molten-Salt E a ~ c t o rExperiment excluded s a l t , b u t t h e t o t a l r a d i a t i o n d o s e w a s too low t o make r a d i a t i o n damage a problem, and e x c l u s i o n of xenon was mot a s p e c i f i c a t i o n . Although a g r a p h i t e s t r i n g e r from t h e E R E showed no e f f e c t o f 2.5 years i n c o n t a c t w i t h f u e l s a l t , i t would n o t have m e t t h e r a d i a t i o n damage and as p e r m e a b i l i t y requirements of a n MSBR. Radiation damage in most graphites results in shrfnkage f ~ l l ~ by ~ e d

expansion at: neutron f l u e n c e s below t h o s e of i n t e r e s t f o r WBRs. Mowever, s p e c i a l g r a d e s of g r a p h i t e show l i t t l e s h r i n k a g e and a l o n g e r p e r i o d b e f o r e r a p i d expansion begins. A commercially a v a i l a b l e g r a p h i t e i r r a d i a t e d a t MSBR temperatures w a s found to meet t h e f o u r - y e a r - l i f e assumption of the r e f e r e n c e d e s i g n . Although a material having adequate r a d i a t i o n r e s f s t a n c e appears to b e a v a i l a b l e , a growing understanding of r a d i a t i o n behavior should l e a d t o l o n g e r i r r a d i a t i o n l i f e , thereby d e c r e a s i n g t h e frequency w i t h which p a r t of t h e g r a p h i t e must be r e p l a c e d .

...

S e a l i n g g r a p h i t e t o exclude xenon i n v o l v e s t h e u s e of p y r o l y t i c carbon d e p o s i t e d i n t h e s u r f a c e pores o r i n a t h i n l a y e r on t h e g r a p h i t e s u r f a c e . E i t h e r method w i l l seal t h e g r a p h i t e adequately, b u t t h e p e r m e a b i l i t y o f most of t h e small samples t e s t e d has i n c r e a s e d e x c e s s i v e l y d u r i n g n e u t r o n i r r a d i a t f ~ n . The f a i l u r e s are thought t o result from d e f e c t s i n t h e s u r face coating of the unirradiated material seen fn photographs o b t a i n e d using t h e scanning e l e c t r o n microscope. A new procedure f o r d e p o s i t i n g

If a suitable n~nethodfor sealimg the saphite is met developed the breedimg ra%is of the MSBR will decrease by 6.005 ts 0.01 because of increased change im breed%mg ratio meu%rom cap%u%es in 135Xe9 with %be specific depending om the effectiveness sf %he msble-gas spargimg system. Wsrk will be carried out om graphite developannemtwhich imcludes s%udies sf a basic mature comcermimg dzunagemechamisnns, fabrieatfsm studies to develop graphite with improved dimemsismal stability, deveh~prnemt of sealimg methods for reducing the penneabilirsy of %he graphite ts 135%e, amd measurmIlemts of %h@physical properties of graphites having potential for MSBR application.

A%tbsugh mamy of the esqomemts and system

for am MSBR power plant are the desigm requirements for other eoHlomemts are differem%, and a number are umique ts mltem-salt systems a Mamy compomem%swere investigated im the develspn~emt program fcm the Aircraft Reactor perimemt and the MoPtern-Salt Reactor Experimemt, but mot 1 have beem develspe and imcre~es in size or perforaraamen are requ d im met Gases. ieal-shaft eem%rifugaP punps with averhung impel%ers wa-e develbsped and used satisfactorily om the Aircraft Reactor Experi~memt (ARE), t-he Molten-Salt Reactcr IXxperimemt, amd a mumto E5-fold increase im capacity will salt Isaps. Al%hough a 10ed im prsgressim frown %he MSRE %o fulli-size MSBRs, tie S~ITMZ basic as %?a%used on %he MSRE is specified im %he referemee MSBR design, amd the scale-up should be rela%ive%y straightforward. me MSBWimtermediate heat exchanger operated wi%hsm% difficulty, and andyses showed m6 decrease in perfsr~amse thromgksut the pIam% Pife. similar

tkEsse

solid-fuel

%ea@%oPs,

The aspects of the MSBR %h%%differ fronr %hc?MS s aside from size, have ko do wi%b %he need for high perfsnnamce in the MSBB to %iti% %he fueE salt imvemtory, and the requirereemt that failed %ubes cam either be located and plugged in place or %ha%a tube bumdle or entire umi% cam be rep%aced. Both of etaese appmaches creatx desigm problem. Ihwever, mew teehmiques for pduggimg heat exehamger tubes being developed for sther uses should be he%pful. There were no s%eam gemerators om %he A md tiere has been ma experiemse with the gemeratiom 0% s% --mdtimg salts e The jar problem is that in csmvemtiamal stea~a ctyeles, the feed water emteks the steam gemeratsr a% a temperature below the weltimg psimt sf %he flusroborate (725°F) 0 As a resralt, umless other measures are %&em, sa4n1esaP% would freeze om the tubes. a layer sf salt to %O~DImight be aczczegkable, but im the referewe comcept, the steam cycle has beem altered

1-15 ..... ..,.,..

,.!..s)

to inclrease t h e i n l e t S t e a m tefnpeKatUre. a S m a l l .la12TX3lty% e § U l t s in t h e form of some a d d i t i o n a l equipment and a smlP l o s s in e f f i c i e n c y . Other ways o f overeomfng t h e s a l t - f r e e z i n g problem ~ S appear S f e a s i b l e , such as t h e r e e n t r a n t t u b e approach that appears i n some sodium-heated steam g e n e r a t o r c o n c e p t s . The l f k e l i h o o d of steam g e n e r a t o r Peaks t h a t introduce moisture i n t o the c o o l a n t will r e q u i r e t h a t a cleanup system be provided. h e way t o prevent entry of t r i t i u m i n t o t h e steam system nay b e t o trap i t i n t h e c o o l a n t from which i t would subsequently b e remved. A s i n g l e p r o c e s s i n g system f o r the c o o l a n t salt may be a b l e to a ~ ~ ~ q l f ~ h both requirements.

.... e

The n o b l e gases are only s l i t l y s o l u b l e i n f u e l s a l t , and csnsequentPy, t h e f i s s i o n product p o i s o n i n g i n an MSBR can b e greatly reduced by sparging xenon f ~ o mt h e salt as w a s demonstrated i n t h e MSRE where over 802 Qf the 135xE? removed. &lWeVer, t h e Somewhat different s p a r g h g SyStelll proposed f o r t h e MSBR r e q u i r e s demonstration, and tests with s a l t are planned i n a l a r g e e n g i n e e r i n g Poop that has been completed r e c e n t l y . g beS t u d i e s will a l s o be c a r r i e d o u t i n t h i s system f o r d e t e ~ d n i ~ . lthe haViOP of tHitfUlil i n a large f u e l Salt C f K c U f t and t h e level sf o d d e eontaminati~ni n t h e f u e l s a l t t h a t would cause troublesome precipitation of uranium from t h e s a l t . %e p r i n c i p l e s of any p r o c e s s e s found n e c e s s a r y t o contr01 t h e oxide c o n c e n t r a t i o n will b e demonstrated. Experience w i t h the f l u ~ r o b o r a t ecoolant proposed f o r the MSBR is n o t e x t e n s i v e , b u t an i s o t h e r m a l MSWE-scale l o o p and a number of small forcedand n a t u r a l - c o n v e c t i o n l o o p s have been o p e r a t e d with t h i s s a l t . Fhorob o r a t e has a g r e a t e r tendency to p i c k up ~ ~ ~ i s t ht aun ~other e s a l t s that -salt which makes i t mere C O ~ K C P B ~ Vbut ~, have been used i n ~ ~ t ~ f t e ~ reacmrs the COHrOSioB Kate W i t h c l e a n S a l t is modest. me BFs Vapor pr@Ssr%rE! requries s p e c i a l p r o v i s i o n s i n the cover gas system, but these have been Worked Out SatfSfactOKilY t h e lC3Ops t h a t have been Operated. S t u d i e s will. b e c a r r i e d o u t in t h e MSRE-scale engineerin loop for d e t e r d n i n g t h e b&avisr ~f mitiurn and hydrogenous s p e c i e s It l a r g e css%ant-salt c i r c u i t s , f o r determining t h e d i s t r i b u t i o n and b v f o r of c o r r o s i o n p r s d u c t s , and f o r developing f u r t h e r t h e techno1 r e q u i r e d f o r use of flusrobsrate as t h e secondary coolant f o r Parge E B R system.

16.2.10

Maintenance

'Fgte Kklai€It@Ha2LflCX Of a16 lrea@torSH@qUireS the per%QIP~l.lce of V a r i O U S meehanfcalb operations on equipment, which became of r a d i o a c t i v e cont a m i n a t i o n and a c t i v a t i o n , i s not d i r e c t l y accessfble to maintenance upon the level of activityp the s i z e of equipment, ions f o r maintenance, a n y t h i n g from s i m p l e , local

1-16 s h i e l d i n g t o f u l l y remote m a n i p u l a t i o n s may b e r e q u i r e d . The t i m e r e q u i r e d t o do maintenance and t h e c o s t of t h e maintenance p r o v i s i o n s i n c r e a s e w i t h t h e d e g r e e sf remoteness r e q u i r e d .

The c i r c u l a t i n g f u e l r e a c t o r has f i s s i o n p r o d u c t s and i n t e n s e r a d i a t i o n w i t h which t o contend, not only i n t h e r e a c t o r vessel, but a l s o i n a l l Of t h e primary c i r c u i t through which t h e f u e l s a l t c i r c d a t e s , t h e o f f g a s system, and i n t h e f u e l p r o c e s s i n g p l a n t . Thus, t h i s KESC~OP concept r e q u i r e s r a d i o a c t i v e maintenance of a g r e a t e r scope t h a n does a f i x e d f u e l r e a c t o r . On t h e o t h e r hand, the r e f u e l i n g o p e r a t i o n i s s i m p l e r , t h e r a d i o a c t i v i t y i s r e t a i n e d o n - s i t e w i t h i n one containment, and t h e n e c e s s i t y of a s e p a r a t e maintenance o r g a n i z a t i o n and equipment f o r a fuel r e p r o c e s s i n g p l a n t a t a n o t h e r s i t e i s avoided. Although maintenance d e s i e f f o r t s cannot affect t h e s i z e and a c t i v i t y level of t h e components i n a r e a c t o r , muck can b e done i n t h e d e s i g n s t a g e s of t h e p l a n t to i n f l u e n c e s t r o n g l y the d e g r e e of a c c e s s i b i l i t y and t h e complexity of t h e maintenance o p e r a t on. The maintenance concept f o r all MSBW is ChaKaCteriZed by t h e fO116Wh g e n e r a l p r i n c i p l e s :

(1) Each system i s composed of manageable u n i t s j o i n e d by s u i t a b l e d i s c o n n e c t s and l i n e s which c a n be c u t and rewelded r e m u t e l y . Each u n i t i s a c c e s s i b l e and r e p l a c e a b l e from d i r e c t l y (2) above through removable s h i e l d i n g . (3) F a i l e d u n i t s a r e remved and r e p l a c e d . Much of t h e maintenance e x p e r i e n c e on which t h i s concept rests r e s u l t e d from a p p l i c a t i o n of t h i s approach to t h e MSm. Only the s i m p l e s t sf i n s p e c t i o n s and r e p a i r s c o u l d b e done on f a i l e d equipment f o r t h e MSRE; however, i n an MSBR, economic c o n s i d e r a t i o n s will d i c t a t e considerat8on of more e x t e n s i v e r e p a i r c a p a b i l i t i e s . It i s c l e a r l y e s s e n t i a l t h a t maintenance d e s i g n and development be conc u r r e n t with p l a n t d e s i g n , and t h i s has been t h e case i n c o n c e p t u a l design s t u d i e s to d a t e . These s t u d i e s have n o t i n d i c a t e d any i n s u m u n t able prob%em in m a i n t a i n i n g a lCB00-P.fId&e) NSBW, and no s e r i o u s c o n f l i c t s have arisen i n imposing t h e maintenance requirements on t h e r e a c t o r sy s t em.

Most of t h e t e c h n i q u e s and many of t h e t o o l s r e q u i r e d for maintenance o p e r a t i o n s have been developed. S e v e r a l v e r s a t i l e maintenance shields have been b u i l t and used. O p t i c a l viewing equipment -window i n s e ~ t s , p e r i s c o p e s , adequate l i g h t i n g - a l l are a v a i l a b l e . The u s e of a s h i e l d e d maintenance c o n t r o l room with windows, remotely o p e r a t e d TV, and remotely c o n t r o l l e d c r a n e s and t o o l i n g , has been s u c c e s s f d l y demonstrated Remotely o p e r a b l e d i s c o n n e c t s for e l e c t r i c a l powers i n s t r u m e n t a t i o n , an4 service p i p i n g are a t a s a t i s f a c t o r y s t a t e of development. The remote f a b r i c a t i o n of brazed j o i n t s i n small system p i p i n g has been demonstrated in Comectiofa W i t h t h e MSRE.

c.... .zs

1-17 important t e c h n i q u e s t h a t are r e q u i s i t e s f o r m a i n t a i n i n g l a r g e power r e a c t o r s are n o t avai%abPe, however. They are remote welding and postmaintenance i n s p e c t i o n . It i s h i g h l y d e s i r a b l e from t h e s t a n d p o i n t o f r e l i a b i l i t y t h a t t h e MSBR f u e l c i r c u l a t i o n system b e of all-welded cons t r u c t i o n ; t h u s , remote c u t t i n g and rewelding of t h e system p i p i n g w i l l Present generation b e r e q u i r e d i n t h e replacement of major components automatic welding machines are r e l i a b l e and capable of making high q u a l i t y welds. These machines are n o t ROW c a p a b l e of f u l l y remote welding, and work w i l l b e c a r r i e d o u t t o a d a p t them for MSBR maintenance requirements. The p r o v i s i o n s i n t h e MSBR f o r access t o equipment f o r maintenance operat i o n s a r e e q u a l l y a p p l i c a b l e t o i n - s e r v i c e i n s p e c t i o n . Dependable applic a t i o n of common methods f o r n o n d e s t r u c t i v e i n s p e c t i o n of welds w i l l be d i f f i c u l t i n high-temperature, h i g h - r a d i a t i o n environments. Related methods c u r r e n t l y being pursued i n AEC and i n d u s t r i a l programs promise t o b e s u c c e s f u l , and t h e n e c e s s a r y work w i l l b e c a r r i e d o u t f o r develepFng remote i n s p e c t i o n methods f o r r e a c t o r welds under MSBR c o n d i t i o n s .

1.2.11

I n s t r u m e n t a t i o n and c o n t r o l s development

A s i g n i f i c a n t e f f o r t i n t h e development of MSRs w i l l b e devoted to t h e s t u d y o f methods f o r s o n t r o % l f n g t h e r e a c t o r s y s t e m d u r i n g s t a r t u p , p a r t l o a d , f u l l l o a d , and under u p s e t c o n d i t i o n s ts d l o w proper assessment of t h e o p e r a t i o n a l and s a f e t y i m p l i c a t i o n s of v a r i o u s c o n t r o l approaches. While i t appears t h a t i n s t r u m e n t a t i o n and c o n t r o l s s y s t e m for MSBRs a r e r e l a t i v e l y s t r a i g h t f o r w a r d , a number of f e a t u r e s i n h e r e n t i n t h i s r e a c t o r t y p e d i c t a t e f u r t h e r development of t h e technology assoc i a t e d w i t h t h e c o n t r o l methods and s y s t e m .

Work i n t h i s area w i l l b e r e s t r i c t e d i n i t i a l l y t o demonstrating t h a t .... .&

... .... .-

,. :i.y

... ....

... *x...

.... ..;...

.!.+<

s a t i s f a c t o r y c o n t r o l methods c a n b e d e v i s e d for t h e v a r i o u s o p e r a t i o n a l modes n e c e s s a r y f o r m o l t e n - s a l t r e a c t o r s , and t h e i d e n t k f i c a t i o n and development of i n s t r u m e n t a t i o n r e q u i r e d f o r u t i l i z a t i o n of c o n t r o l methods having t h e greatest p o t e n t i a l . The work w i l l be c o n ~ e n t r a t e dprimarily on t h e r e q u i r e m e n t s f o r a lOOB-MW(e) MSBR in o r d e r to i d e n t i f y technology areas r e q u i r i n g f u r t h e r development and demonstration b e f o r e and d u r i n g o p e r a t i o n of m o l t e n - s a l t test and demonstration r e a c t o r s . S t u d i e s w i l l b e c a r r i e d o u t as n e c e s s a r y f o r c h a r a c t e r i z i n g t r a n s i e n t s which may o c c u r d u r i n g normal a c c i d e n t c o n d i t i o n s w i t h t h e p r e f e r r e d c o n t r o l methods i n o r d e r t h a t t h e s e c o n d i t i o n s can b e c o n s i d e r e d p r o p e r l y d u r i n g t h e development of components and materials f o r t h e v a r i o u s r e a c t o r s y s t e m . As t h e d e s i g n s p r o g r e s s f o r test m d demonstration r e a c t o r s , more d e t a f l e d a t t e n t i o n w i l l b e given t o t h e c o n t r o l requirements f o r t h e s e r e a c t o r s .

1.2.12

Molten-Salt Test Reactor mockup

The development work o u t l i n e d p r e v i o u s l y w i l l be aimed a t p r o v i d i n g t h e technology r e q u i r e d f o r d e s i g n of components f o r a m o l t e n - s a l t test r e a c t o r ; however, a number of important a s p e c t s r e l a t e d t o test r e a c t o r

1-18

Other benefits which w i l l accrue from work associated with t h e test reactor mockup include obtaining e eriefbce d u r i n g t h e d e s i g n and construction phases which w i l l b e dir tly a p p l i c a b l e t~ the test reactor, pKQVidfng afll opp0PtUnitg f 8 P testing O f remot@ KQahteWnCe eqUi&X€Ent and techniques prior to test reactor o p e r a t i o n , and allowing an opportUnityP f O K C?p&%KatC?r t r a h h in support 0% t h e test reactor.

1.2.13

Malten-Salt Test Reactor

Neither t h e optimum size nor e8 l e x i t y of the t e s t reactor has been determined at t h i s time. If at all possible, the test r e a c t o ~shckild be sufficiently large that experience can be obtafned w i t h components that are f u l l scale f o r a d e a ~ n ~ t ~ a t ireacto~. on It is anticipated t h a t t h e s t u d i e s outlined hw Section 8 of this prop r e l i d n a r y conceptual d e s i gram plan will lead to a el r definition of the design and o p e r a t i o n a l requirements for the test r e a c t o ~ ~ F . i n d design of t h e system w i l l be completed by the end of FY 1985, and o p e r a t i n should b e g i n e a r l y in FY 1989. me e s t i t e d cost. f o r t h e d e s i n and construction of the

b e considered to b e very p l p e l i m i n a ~since it i s not supportea IS^ deta%ieel or c o s t estilraartion. .....

1-19 1.2.14

Molten-Salt Demonstration Reactor

Selected key program milestones and the t i m e a t which they occur a r e defined and shown i n Tables 1.3.1 thru 1.3.4. A more d e t a i l e d listing of key program m i l e s t o n e s f o r each of the Program areas is given in t h e r e s p e c t i v e section of t h i s program plan.

;.&

.& ....

.... ..... , :.x*

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....

Table

Scbedde

1.3.1.

Development

area

for mlten-salt xeaefor development &owing (See Table 1.3.3 for xemafnfng devdopment

selleeeed areas -1

key program

miLestones

1-21 Table 1.3.2. D e s c r i p t i o n o f s e l e c t e d key program m i l e s t o n e s f o ~ m o l t e n - s a l t r e a c t o r development appearing i n Table 1.3.1 (See f o l l o w i n g t a b l e s f0-r remaining development areas 1 e

*a ,....

....

g.&.

..... !.id

...

Miles tone

Deseription

Determine a c c e p t a b l e a l l o y composition f o r MSBR p r i m a r y c i r c u i t .

P K O C Us e~v~e r a l Parge commercial h e a t s of a l l o y chosen f o r MSBR primary c i r c u i t .

Submit ASMF, code c a s e f o r u s e of a l l o y chosen f o r MSBR primary circuit.

Receive a u t h o r i z a t i o n of MSBR Processing Engineering Laboratory.

Receive a u t h o r i z a t i o n of I n t e g r a t e d P r o c e s s T e s t F a c i l i t y .

Complece o p e r a t i o n of e n g i n e e r i n g f a c i l i t i e s f o r s t u d y of s i n g l e p r o c e s s steps.

Complete c o n s t r u c t i o n of MSBR P r o c e s s i n g T e s t F a c i l i t y .

Begin o p e r a t i o n of I n t e g r a t e d P r o c e s s Test F a c i l i t y .

Complete o p e r a t i o n of I n t e g r a t e d P r o c e s s T e s t F a c i l i t y .

Complete c o m p a t i b i l i t y s t u d i e s r e l a t i n g to s e l e c t i o n of g r a p h i t e for I n t e g r a t e d P r o c e s s T e s t F a c i l i t y .

Complete s u r v e i l l a n c e s t u d i e s on samples from e n g i n e e r i n g f a c f l i t i e s f o r s t u d y of i n d i v i d u a l p r o c e s s s t e p s .

Complete i n t e r i m r e p o r t on alternate c o o l a n t e v a l u a t i o n .

E s t a b l i s h s o l u b i l i t y of t e l l u r i u m and t e l l u r i d e s i n f u e l s a l t .

Complete f i n a l e v a l u a t i o n of alternate c o o l a n t s .

Complete measurements of t r i t i u m permeation of c l e a n and oxidized metals.

Complete data r e q u i r e d f o r modeling of t r i t i u m behavior i n PlSBRs

Complete development of e l e c t r o c h e m i c a l and s p e c t r o p h o t o m e t r i c a n a l y s i s methods f o r c o r r o s i o n p r o d u c t s and tritium Fn sodium fluoroborate.

Complete development of i n - l i n e method f o r o x i d e a n a l y s i s i n f u e l salt.

Complete e v a l u a t i o n of y-spectrometry c a p a b i l i t i e s .

Complete recommendations f o r a n a l y s i s requirements of MSBRs.

Complete s a f e t y a n a l y s e s r e q u i r e d t o s u p p o r t r e q u e s t f o r a u t h o r i z a t i o n of MSTR and MSTR mockup.

Gsmpfete development of s a f e t y technology r e q u i r e d f o r MSTR

.... a

lieensing a

Complete s a f e t y a n a l y s i s work f o r KSTR.

&& .

1-23 .... ,:*a

... ,*a

Table 1 . 3 . 4 . D e s c r i p t i o n of s e l e c t e d key program m i l e s t o n e s for m o l t e n - s a l t reactor development a p p e a r i n g i n Table 1 . 3 . 3 (See preceding t a b l e s f o r remaining development areas.) Milestone

... .... * a

.....a ,

Descrip t i o n

Complete studies of a l t e r n a t e d e s i g n s and uses f o r MSRs.

E s t a b l i s h i n t e r i m high-temperature d e s i g n methods f o r MSBR materials.

Complete p r e l i m i n a r y c o n c e p t u a l d e s i g n o f 1BOO-m(e) MSBR.

Establish d e s i g n c r i t e r i a f o r L300sF o p e r a t i o n .

Complete d e s i g n r e p o r t s on s e l e c t e d MSR s u p p o r t i n g systems.

Determine r e f e r e n c e g r a p h i t e f o r MSBR moderator from commercial g r a p h i t e s .

...

Determine b e s t method for reducing p e r m e a b i l i t y of g r a p h i t e t o 135xe* h

Complete d e ~ d . o p m e ~sf t model f o r g r a p h i t e s i n g l e c r y s t a l s relbathg damage t o electran and n e u t r o n i r r a d i a t i o n . Begin i r r a d i a t i o n of p r o t o t y p i c moderator element made of reference graphite e

Begin f a b r i c a t i o n o f experimental q u a n t i t i e s of graphites having improved i ~ ~ a d i a t i odamage n resistance.

Complete measurements of p h y s i c a l p r o p e r t y v a r i a t i o n s of r e f e r e n c e g r a p h i t e in i r r a d i a t e d and untrradiated c o n d i t i o n s . Begin h r a d f a t $ o n of p r o t o t y p i c moderator eEem€%lt. E s t a b l i s h f e a s i b i l i t y of using Bower steam system feedwater temperatures 0

Obtain i n d u s t r i a l r e ~ o ~ t ~ ~ n d af ot ri ~steam f ~ s g e n e r a t o r development program. Complete d e f i n i t i v e engtneering tests on removal of xenon from f u e l s a l t . Complete tests f o r determining behavior of tritium and c o r r o s i o n p r o d u c t s i n f l u o r o b o r a t e c o o l a n t

salt np

Complete r e s o l u t i o n of all problems p e r t a i n i n g t o behavior of tritium i n f u e l salt system. Complete r e e v a l u a t i o n of steam g e n e r a t o r development program. Complete p r e l i m i n a r y valve development. required f o r HSTW d g s i g ~ ~ Obtain . authori z a t i o n of Component Test F a c i l i t y .

Complete e o n s t r u s t i o n of Steam & n e ~ a t o l : Tube T e s t Stand, p r e s s u r e relief system, and 3-M4 test assembly.

Complete d e s i g n of MSTR p r o t o t y p e pump and pump test s t a n d .

Complete c o n s t r u e t i s n of component T e s t F a c i l i t y .

1-24

Table 1 . 3 . 4 (continued) M i l e s tone

Description Complete tests in Steam Generator Tube T e s t Stand. Complete construction sf 30-MM model steam generator and Steam Generator Hodel Test Installation. Complete construetion of MSTR prototype pump and pump test stand.

Complete large-scale demonstration tests of coolant-salt technology Complete resolution of all problem associated W i t h CQVeP and Off-gas SySteH19. CQIIIPlt2te d l pKiITGTKY heat exchanger work required f o r MSTR design. e

in t e s t s of prototypic MSTR steam generator in NSTR moekup e

Complete determination of MSBW maintenance requirements.

Complete maintenance developmnt ~ e q u i r e d%or MSTR design.

Complete development of MSBW control methods.

Complete conceptual d e s i g n .

Obtain authsrization.

Complete final d e s i g n .

b”

CQIUplete ConstrUCtion.

u.1

Table

1.4.1.

Summry

of operating fund requirement5 for naolten-salt (caste irn thousand5 of FY 1975 dollars) Fiscal

Developmemt

of structural

Fuel

processing

Fuel

processing

Chemical

materials

research

Analykical

materials

development

and development

reseaarch

tiactor

safety

Reactor

design

Graphite

development

Reactor

technology

and development

and analysis

Total

HSSBBtechnology

1977

I978

1979

1980

1981

1982

1983

1984

1985

1671

2150

2327

2,764

1,468

1,350

1,200

1,240

1,180

1,200

1,020

931

1600

1825

1,795

595

465

591

2,458

2,824

2,700

123

300

393

461

489

375

473

710

811

913

11,014

1,014

1,255

1,450

1,230

610

440

180

290

360

41a

480

515

553

550

513

460

365

233

270

360

305

520

645

750

845

950

moo

122

467

530

540

695

1,000

1,QOQ

850

8QO

750

700

450

514

579

643

1,210

1,285

1,260

1,210

1,110

800

970

1,080

1,440

2,595

3,735

3,500

3,750

4,000

200

486

791

597

518

486

435

141

270

370

545

550

600

9,000

7,470

9,aoQ

11,500

13,275

13,500

13,120

P2,4QO

630

700

850

1,500

2,500

3,000

3.000

2,000

4,750

2,500

2,650

2,5QO

3,000

3,500

4,000

2,000

5,380

3,200

3,500

4,000

5,500

6,5QO

7,000

11,000

12,850

13,000

15,QQO

17,275

19,000

19,620

B9,408

--4000

7000

8000

WBTR mockup MBTR Total reactor design and developtnent Total MSBR technology and reactor design and development

year

1976

410

and controls

development.

1975

Maintenaasce Tnstromentation

reactor

--4000

7000

8bOO

B9a6

735

9QQ

1155

715

425

62Q

125

157

273

2%8

I.39

314

251

267

208

153

156

I.41

I542

145

236)

120

63Q

576

210

290

425

2QQ

PO5

100

180

12QQ

1382

-915

390

130

13%

400

200

178 2211

2031

152Q

1570

1552

Table 1.4.3.

Capital

prsject funds required for molten-salt (casts in milPions of FY 1975 dollars)

reacmr

Fiscal 1976 MSBR Prcscessimg Engineering Integrated

Laboratory

1977

1978

year

19-IF% 1980

l.9 81

Process Test Facility

steam generator tube test stand Pllmp test

devekqmlent

4 1

stand

Csmponents Test Facility Model steam generator

10 test

Molten

salt

test

reactar

Molten

salt

test

reactor

Total

capital

project

installation

mockup

funds

50 12

61.

454) 470

1982

1-28 REFEWNCES POW SECTION 1

DEVELOPMENT OF STRUCTURAL F53TlhL FOR

PRIMARY AND SECONDARY CIRCUITS 2.1

PNTRODUCTEOM

The material used in c o n s t r u c t i n g t h e MSBR primary c i r c u i t w i l l o p e r a t e o v e r t h e temperature r a n g e of 1050 t o 1300°F. The environment o u t s i d e t h e primary c i r c u i t w i l l b e o x i d i z i n g and comprised p r i m a r i l y of n i t r o g e n . The i n t e r i o r s u r f a c e s of t h e primary c i r c u i t w i l l b e exposed t o s a l t c o n t a i n i n g f i s s i o n p r o d u c t s , and w i l l receive a maximum t h e r m 1 n e u t r o n f l u e n c e of about 1 x l O 2 I neutrons/em'. The o p e r a t i n g l i f e t i m e of a r e a c t o r w i l l b e about 250,008 h r (about 30 yr). The material must b e f a b r i c a b l e i n t o many p r o d u c t s , and c a p a b l e o f b e i n g formed and welded by ~ o n v e n t i o n a lshop t e c h n i q u e s . ,;.&

HR t h e secondary c i r c u i t , t h e material w i l l b e exposed t o t h e c o o l a n t s a l t o v e r t h e temperature range $50 t o 1150°F under much t h e same cond i t i o n s as f o r t h e primary c i r c u i t e x c e p t f o r t h e absence of f i s s i o n p r o d u c t s and n e u t r o n i r r a d i a t i o n . Thus, t h e a c t i v i t i e s r e q u i r e d f o r development of material f o r t h e primary c i r c u i t w i l l s u f f i c e f o r the secondary c i r c u i t if s u p p l a n t e d by i n f o r m a t i o n on t h e c o m p a t i b i l i t y of t h e material w i t h t h e c o o l a n t s a l t . 2.1.1

Objective

The o b j e c t i v e of t h i s program is t o develop a material t h a t w i l l o p e r a t e s u c c e s s f u l l y ~ n d the e ~ c o n d i t i o n s d e s c r i b e d above.

2.1.2

... .....

:.&A

.:&

.:.a

Scope

HastelPoy N w a s t h e s o l e m e t a l l i c material used in c o n s t r u c t i n g t h e MSWE. Although t h e m i s s i o n of t h a t reactor w a s n o t compromised, e x p e r i e n c e r e v e a l e d t h a t H a s t e l l o y N was e m b r i t t l e d by n e u t r o n i r r a d i a t i o n and formed i n t e r g r a n u l a r cracks due t o i n t e r a c t i o n w i t h t h e f i s s i o n product t e l l u r i u m . More r e c e n t experiments have shown t h a t chemical modificat i o n s of H a s t e l l o y N are q u i t e e f f e c t i v e i n i n c r e a s i n g t h e r e s i s t a n c e of t h e material t o e m b r i t t l e m e n t by n e u t r o n i r r a d i a t i o n and t o c r a c k i n g by t e l l u r i u m . The a c t i v i t i e s d e s c r i b e d i n t h e r e m i n d e r of t h i s s e c t i o n are aimed a t c o n t i n u i n g t h e a l l o y development e f f o r t i n o r d e r t o o b t a i n a code-approved s t r u c t u r a l material f o r t h e primary and secondary c i r c u i t of m o l t e n - s a l t r e a c t o r s having a d e q u a t e r e s i s t a n c e t o e m b r i t t l e m e n t by n e u t r o n i r r a d i a t i o n and a t t a c k by t h e f i s s i o n product t e l l u r i u m . The work areas t o b e undertaken i n t h i s a c t i v i t y c o n s i s t of (1) d e t e r m i n a t i o n of an a c c e p t a b l e a l l o y composition, (2) procurement of commercial h e a t s of t h e s e l e c t e d a l l o y , (3) e x t e n s i v e e v a l u a t i o n tests on product shapes from t h e commercial h e a t s , ( 4 ) t h e development of deslgn methods and d a t a f o r t h e selected a l l o y and submission sf an ASME code case for u s e of the material i n n u c l e a r service, and (5) s t u d i e s f o r o p t i m i z a t i o n of t h e a l l o y properties.

2-1

2 -2

2.1.2.1

Task Group 1.1

Selection of a l l o y compositFon

Tests w i n b e c a r r i e d o u t t o determine b a s i c i n f o r m t i o n r e l a t e d t o chemical i n t e r a c t i o n s between HastellogT N, tellurium and S a l t . The r e a c t i o n products formed in the alloy wi11 b e i d e n t i f i e d and r a t e d a t a associated with t h e i r formation w i l l b e measured. Various a l l o y s will b e irradiated to determine t h e i r r e s i s t a n c e to n e u t r o n embrittlement. An important v a r i a b l e i n t h e s e s t u d i e s w i l l be t h e a l l o y c o ~ ~ ~ p o s i t i ~ n . EmphasPs will be p l a c e d on a modified Hastellsay N having a base composit i o n of 12% Mo9 7% cr, 0.05% c, b a l a n c e Ni. Additions of Ti up to 2% and rare e a r t h s ( e . g . , Ce, La) up t o 0.02% w i l l b e e v a l u a t e d . ‘Ehe end r e s u l t of work i n this task group w i l l b e t h e s e l e c t i o n of an a l l o y W i t h adlE?~lX3teke%iStaSlC@ nf2U%rone€LlbKitt1€XQt?n% and i n t e r g r a n u h r c r a c k i n g f o r u s e i n m o l t e n - s a l t r e a c t o r s having a 30-yr l i f e .

2.1.2.2

M t e r t h e composition of modified HastePEoy N has been f i x e d by t h e work i n Task Group 1.1, a t least f o u r l a r g e comercial heats (Qk0,00CB l b each) w i l l be procured for e v a l u a t i o n . The s p e c i f i c a t i o n s w r i t t e n f o r t h e procurement of t h h material wfll form t h e basfs f o r future p%-oCur@lXleflt f o r constrUc2tfon O f %eaCtQr Sy§telRS. OPderS for t h e f o u r h e a t s will be p l a c e d w i t h a t least two vendors by c o m p e t i t i v e bidding. The material w i l l b e o b t a i n e d i n product f o r m t y p i c a l l y r e q u i r e d i n reactor c o n s t r u c t i o n . These mterials will b e ~ a ~ e f u l cl ayt a l o g u e d and e v a l u a t e d e x t e n s i v e l y in Task Group 1.3.

2.1.2.3 forms f K O I U the f o u r kiH e h e a t s w i l l be e v a l u a t e d w i t h r e s p e c t t o several p r o p e r t i e s i n c l u d i n g weldab Pity, mechanical p r o p e r t i e s , c o m p a t i b i l i t y with f u e l s a l t c s n t a i n i n f i s s i o n products and c o o l a n t s a l t , and p h y s i c a l p r o p e r t i e s . These es ts w i l l confirm the des i r a b Ility of t h e cswpositisn s e l e c t e d and w i l l p r u v i d e the d a t a b a s e r e q u i r e d for of %fa components and systems. Tests of at l e a s t 10,QOO hr duraill be carried orat. me quality s f t e s t i n g w i n b e mintainea at level t o p r o v i d e i n f o m a t i o n having t h e p r e c i s i o n necessaq f o r d e s i g n purposes. I”rOdUCt

me data o b t a i n e d in Task Group 1 . 3 w i l l be a n a l y z e d and c o r r e l a t e d Tan a n a l y t i c a l forms t h a t are most easily used b y designers. Model tests necessary to develop high-temperature d e s i = methods w i n be carried o u t . The da%aand t h e d e s i g n methods % p i l l allow p r e p a r a t i o n and submission of a h i -temperature Asm P r e s s u r e Vessel Code ease f o r base of t h e material h n u c l e a r service.

2-4

The tests performed in Task Group 1 . 3 w i l l b e adequate f o r the d e s i g n o f a m o l t e n - s a l t t e s t r e a c t o r . However, t h e o p e r a t i o n of t h i s and subsequent r e a c t o r s would profit from t h e a v a i l a b i l i t y o f longer-term information. Some of the C O K ~ O S ~ O W c r~e e p , and fuel i r r a d i a t i o n tests initiated in Task Group 1 . 3 w i l l b e continued t o provide t h i s iRforlE3tion. 2.1.2.6

Task Group 1 . 6

Alloy o p t i m i z a t i o n

Although the a l l o y t h a t w i l l r e s u l t from work i n Task Groups 1.1 through 1.4 s h ~ i a l db e adeqmte for c o n ~ t r u c t i ~of n ip m o l t e n - s a l t test reactor ( S e c t i o n 141, a demonstration r e a c t o r (Section 151, and c o m e r ~ i a lpower K € ? a c t O r S , i t iS l i k e l y that f u r t h e r alloy deVdOpElent w i l l lead g S m a t e r i a l s having improved c h a r a c t e r i s t i c s which may allow a h i g h e r r e a c t o r o u t l e t s a l t temperature o r s i g n i f i c a n t r e l a x a t i o n of design and operat i o n a l c o n s t r a i n t s . Some a t t e n t i o n w i l l a l s o b e given i n t h i s t a s k group t o the use of c h e a p e r , more r e a d i l y a v a i l a b l e materials ~ S S~ o n s t r ~ c t i o n Of power r e a c t o r s .

2 2 1 Schedule and key program m i l e s tones

The The s c h e d u l e f o r work i n t h i s a c t i v i t y i s given i n Table 2.2.1.1. key program milestones a s s o c i a t e d w i t h t h e devellopment of t h e s t r u c t u r a l metal for the MSR primary and secondary c i r c u i t s are l i s t e d i n Table 2.2.1.2 and OCCUP a t the t i m e s i n d i c a t e d in Table 2.2.1.6. 2.2.2

The material used i n t h e lprimry s i r c u i t w i l l b e exposed t o fertsklef i s s i l e s a l t c o n t a i n i n g fission p r o d u c t s o v e r the temperature r a n g e of In the fntermediate heat exchanger and i n t h e r e m i n d e r 1050 t o 1308'F. of t h e secondary circplt$f: t h i s material w i l l be exposed t o t h e c o d a n t salt. The outside surfaces of t h e a l l o y w i l l be exposed t o t h e cell E%TViKOIIIDentWhich W i l l likely be nitrogel? Containing 2 %S 5% S q g e n . No metallic structural. me&ers w i l l b e loeared in t h e highest flux

Table

2.2.1.1.

Schedule

for

development

structural

metal

for

primary

1980

Determination

of alloy

saupositioei

Procurement

csmersial

heats

EvaluatPon

sonunerslal

heats

Development of analytical nlethods - ASME Code Long-term Alloy

materPaP

opti.mizatisn

tests

design

and secondary

1982

circuits

2 -5

Table 2.2.1.2.

Key m i l e s t o n e s f o r development of s t r u c t u r a l metal for primary and secondary c i r c u i t s

Receipt of s m a l l commercial h e a t s c o n t a i n i n g 2% T i p l u s W . 0 1 X rare e a r t h s . Begin mechanical p r o p e r t y and c o m p a t i b i l i t y tests on 2% Ti-rare-earth h e a t s . R e c e i p t o f s e v e r a l l a b o r a t o r y melts c o n t a i n h g v a r i o u s amounts of T i and Hb. Begin mechanical p r o p e r t y and c o m p a t i b i l i t y tests on Ti-Nb modiffed a l l o y s .

Receipt o f p r o d u c t s o f 10,006-lb h e a t of 2% T i - m d i f b e d HastePloy N . Begin mechanical p r o p e r t y and c o m p a t i b i l d t y tests on PO,006-lb heat.

S t a r t f o r c e d convection c o r r o s i o n l o o p (PCL-3) c o n s t r u c t e d of 10,000l b h e a t f o r b a s i c f u e l s a l t c o r r o s i o n s t u d i e s . Begin 21% y r i r r a d i a t i o n of f u e l p i n s made of most d e s i r a b l e a l l o y .

S t a r t f o r c e d convection c o r r o s i o n loop (FCL-4) l b h e a t f o r fuel salt-Te c o r r o s i o n s t u d f e s .

c o n s t r u c t e d of lO,008-

S t a r t f o r c e d convection C O ~ ~ O Sl o~o pQ ~(FCL-5) c o n s t r u c t e d o f 10,008-

lb h e a t f o r c o o l a n t s a l t c o r r o s f s n s t u d i e s . f

P r e p a r e s p e c i f i c a t i o n s and s o l i c i t b i d s from p o t e n t i a l vendors f o r four h e a t s of d e s i r e d composition.

Begin r e c e i p t of p r o d u c t s from f o u r l a r g e h e a t s .

Begin c o n s t r u c t i o n and checkout of equipment r e q u i r e d f o r mechanical p r o p e r t y tests on f o u r l a r g e h e a t s .

Begin e v a l u a t i o n o f f o u r l a r g e h e a t s b y w e l d a b i l i t y , mechanical p r o p e r t y , and c o m p a t i b i l i t y tests.

Begin o p e r a t i o n of forced c i r c u l a t i o n loops (FCL-6 and 7) c o n s t r u c t e d of modified a l l o y and c i r c u l a t i n g f u e l s a l t .

Begin o p e r a t i o n of f o r c e d c i r c u l a t i o n loops (FCL-8 and 9) c o n s t r u c t e d of modified a l l o y and c i r c u l a t i n g c o o l a n t s a l t .

Begin d e t a i l e d a n a l y s i s of mechanical p r o p e r t y d a t a .

Begin development o f d e s i g n methods f o r modified a l l o y .

Submission of d a t a package for ASME Code Approval.

Begin s t u d i e s t o raise a l l a r a b l e t e m p e r a t u r e f o r u s e of modified alloy.

Table 2.2.2.2. Suma9y of capital ecp&ment funds required for development af structural metal for primary and secanaary careeaits (costs in mm dsllars)

I.1

Determination

of alloy

I.2

Procurement

of commercial

hats

1.3

Evalmatian

of comrcial

heats

1.4

Development cd analytical design methods - csae Case Submission

1.5

Long-term

1.6

APloy optimization

Total

capital

material

equipment

camposition

735

563 10 337

1095

290

160

tests

funds

410 ---735

900

1155

390

35 70 -----~75 130

115

135

185

115

105

2-8

r e g i o n s , b u t the vessel w a l l w i l l b e exposed t o peak thermal and fast (>0.8 M ~ V ) f l u x e s of 6.5 x 1012 amd 1.2 x 101' n e u t r o n s * * sec-l. With a 38-year l i f e t i m e and an 80% l o a d f a c t o r , the peak thermal and and 1. x 16'o n e u t ~ o n s / c m ~r ,e s p e c t i v e l y . fast fluences w i l l be 5 x

h obvious requirement of t h e s t r u c t u r a l material i s that it b e f a b r i cable i n t o t h e forms needed t o b u i l d a n e n g i n e e r i n g system. The b a s i c shapes r e q u i r e d i n c l u d e p l a t e , p i p i n g , t u b i n g , and f o r g i n g s For assembly, t h e m t e r i a l must b e weldable both under w e l l - c ~ n t r o l l e d shop c o n e l i t i ~ n s and in t h e f i e l d . 2 3.2 e

Background

2.3.2.1 The nuclear-powered a i r c r a f t a p p l i c a t i o n f o r which m o l t e n - s a l t r e a c t o r s were o r i g i n a l l y developed r e q u i r e d that t h e f u e l s a l t o p e r a t e a t around 1500°F. Inconel 600, o u t of which t h e A i r c r a f t Reactor Experiment w a s b u i l t , w a s not strong enough and corroded t o o r a p i d l y a t the d e s i g n temperature f o r long-term u s e . The e x i s t i n g a l l o y s w e r e s c r e e n e d f o r c o r r o s i o n resistance a t this temperature and o n l y two were found t o b e s a t i s f a c t o r y - H a s t e l h y B (Ni-28% Mo-5x Pel and H a s t e l l a y W (Ni-as% WS-5%~ r - 5~ ~ e )I s 2 h ow ever, b o t h aged a t t h e s e r v i c e t e m p e r a t u r e and became q u i t e b r i t t l e due t o t h e f o r m t i o n o f Ni-Mo i n t e r m e t a l l i c cornp 0 1 ~ 1 1 d ~ . These o b s e r v a t i o n s l e d to an a l l o y development program i n which PNOR-~, ~ a s t e l l o yM, w a s developed. 3 9 4 e

2.3.2.2

The m e t a l l u r g y of H a s t e l l o y N

%e commercial chembcal s p e c i f i c a t i o n s f o r " s t a n d a r d t f Haste%loy N out of which t h e M S E w a s b u i l t , and for a n alloy modified t o give i t i m proved p r o p e r t i e s , are shown i n Table 2.3.2.2. The molybdenum i s p r e s e n t for s t r e n g t h e n i n g , b u t is n o t i n s u f f i c i e n t c o n c e n t r a t i o n t o c a u s e the f o r m t i o n of b r i t t l e c o ~ o m d s . C h r s d m i s added i n t h e ~ r o ni s minimum c o n c e n t r a t i o n r e q u i r e d t o form a s p i n e l - t y p e o x i d e . allowed i n s u f f i c i e n t q u a n t i t i e s t o permit c h r o d u m t o be added as ferrockrome; however, i t i s n o t a c r i t i c a l element i n t h e alloy. Manganf33e has some e f f e c t on t h e alloy b y r e a c t i n g w i t h s u P f u r , but s u l f u r is u s u a l l y d e a l t w i t h d u r i n g m e l t i n g by a d d i t i o n s of elements such as magnesium. Carbon i s i m p o r t a n t b e c a m e i t f o r m c a r b i d e s that improve t h e s t r e n g t h and r e ~ t ~ i gcrta i n g ~ o ~ dt uhr i n g high-temperature t r e a t m e n t s . Elements such as s u l f u r , phosphorus, and boron, and many o t h e r s rtot hClUded in Table 2.3.2.2 are tramp OB: hl$lUKity eleIIE%lts t h a t serve no h o r n u s e f u l purpose i n the alloy. These elements g e n e r a l l y have l i t t l e e f f e c t on t h e alloy b e h a v i o r as l o n g as they are k e p t a t reasonable c o n c e n t r a t i o n s .

2 -9

E1ement

,.:.a

Standard alloy

Favored rnodif ied a l l o y

Nickel

Base

Molybdenum

15-1 8

11-13

Chromium

6-8

6 -8

Iran

O.l**

Nanganese

O.H54.25**

Silicon

8.1

Phosphorus

0.815

0.81

SUlfUK

8.020

8.01

Boron

0.01

8.081

Titanium

*Single values are maximum amounts allowed.

2 T h e actual coneentratfons

of t h e s e elements i n an a l l o y can b e much lower.

**These d e m e n t s are n o t f e l t t o be v e r y important.

Alloys are now b e i n g purchased w i t h t h e small c o n c e n t r a t i o n s p e c i f i e d , b u t t h e s p e c i f i c a t i o n m y b e changed i n t h e f u t u r e t o a l l o w a h i g h e r c o n c e n t r a t i o n .

.... ...... =

r w

. .. k..&

2-10 S i l i c o n is b t r o d u c e d by- the HefractorieS Used in t h e a i K melting pkactice and is an i o r t a n t element. HastelPoy N containing 0.5 to l ; y d s i l i c o n contains er.9 Of COie'BTSe Carbides and Will folpm S O E f i n e earbides d u r i n g annealing a t 1200 to 160O"Fo6 These c a r b i d e s are of the MgC type, d t h M having the c o - o s i t i ~ n of 27.9% M i , 3 . 3 % Si, 0.6% Fe, 56.1% Mo, and 48% CK. They are n o t easily dissolved during annealing, so t h e alloy has s t a b l e p r o p e r t i e s over a broad range of o p e r a t i n g temperatures. However, t h e s e predominantly c o a r s e carbide p r e c i p i t a t e s produce less desirable alloy properties than f i n e carbide p ~ e c i p % t a $ e s of the MC and MzC type. Several laneltfng practices are c u r r e n t l y in u s e t h a t result i n low aiPfcsn eonee matispas. The c a r b i d e s in these a l l o y s are u f the M2C type, where M is 0 t o 98% malybdenm with t h e r e m i n d e r chromium. They a r e more e a s i l y d i s s o l v e d than the M G C type which c o n t a i n s

silicon

2 3 2.3 0

@ o r r o s i s n res is t a n c e o f H a s t e l l o y M

Several hundred thousand hours o f c o r r o s i o n experience with Haste1loy N and f l u o r i d e salts have been obtaf-ned i n thermal convectfon's2 and pumped system These experiments showed that th@ p r e d o d n a n t c o r r o s i o n mechanism i n clean fluoride s a l t s containing uranfum i s the selective leaching sf ehromim. Only 7% of the alboy is ehrsanim and this m u s t d i f f u s e t o the s u ~ f a c eb e f o r e it can be removed by the salt. DeVan measured t h e rate O f chromim diffusion in Haste%loy N , 8 and the measured diffusion coefficients were used ts estimate the chrodum profile a f t e r 30-y S e K V k e at 650 andl 908°C i H n s a l t S U f f i @ i e n t l y ClXidiZfng to COlllpPet deplete t h e a l l o y surface of Cr. Even i n this extreme situation, t h e depth of cplrowim re v a l was less than 10 mils. 0

The early work with Hastelloy N and o t h e r alloys revealed the importance of c o n t r o l l i n g impurities i n t h e salt. Impurity fPuarides such as PeP2, MoF2, and N I P 2 will r e a c t with Cr t o form CrFzs a more s t a b l e f l u o r i d e . Watgr w i l l react w f t h the f l u o r i d e m%xturest o fsm HF that w i l l form fluorides with a61 the s t r u c t u r a l metals. Such inpurities led to relatively hfgh e o r k ~ s i o ~ rates l of even H a s t e l l o y N in the early experiments. However, with pure s a l t mixtures, very low corrosion rates were o b t a i n e d . ultilWtt2 pKOof sf Chis WaS the OpeKat&XI Of the MSm Where t h e OVE?r=a t te all c o r r o s i o n was q u i t e low d u r i n g a l m ~ f~o ut r

2-11

2.3.2.4

The physical and mechanical p r o p e r t i e s o f Nastell%oy N were evaluated 1Pathe-P eXtEYClSiVe.%ybefore t h e MSm WiES C O F l S f r U C t e d %IfaeSe prOpeHti633 have been s u m p i z e d previoksgly.9 me s t r e n g t h o f this a l k o y is quite good because of the 16% molybdenum. The property chan es w i t h time are sm1P s i n c e t h e alloy does n o t form intermetallic G Q E ~ Q ~ E E Bb~uSt only e

small amounts of fine carbides.

2 3.2 .%Experience with Hastelloy N in,t h e MSM

2.3.2.5.1

Fabrication

Although the power level of t h e MSWE w a s l o w % t h e system w a s complex and required the ability to carry o u t all of t h e b a s i s fabrication steps.Eo procured f r o m t h r e e Many thousands of pounds of b a s k product forms vendors. some of t h e csmponemts were built by comercfal vendors, but most of t h e fabrica%ionwas d ~ a ei n t h e AEC-Union Carbide shops at Oak Ridge and Paduct&. Welding, brazing, and inspeetion procedures needed f o eonstructiag ~ the reactor were developed. One of t h e final steps was to make use of the heaters on t h e vessel t o p o s t w e l d anneal t h e final vessel. s l o s u r e weld.

2.3.2.5.2

Operation

No difficulties related to materials were encountered d ~ ~ i MSRE n g operation. The primary system w a s held above 50Q"C for 30,807 hours and w a s filled with f u e l s a l t for 21,040 hours. The only failure involving Hastelloy M was through-wall cracking of a freeze valve solincident w i t h f i n a l shutdown sf t h e systern.12 This failure w a s due to fati dPfferentia1 thermal expansion in a part that was esnstrueted t o o rigidly e

2.3 2 5 3 e

corrosion

2-12

fuel s a l t w a s e q u i v a l e n t t o t h a t which would b e removed from all metal surfaces t o a depth of 0 . 4 m i l ; t h e amount a p p e a r i n g i n t h e c o o l a n t salt w a s p r a c t i c a l l y nil. S u r v e i l l a n c e samples l o c a t e d i n t h e c o r e o f t h e E R E were p e r i o d i c a l l y ~ e m ~ v efor d examination and testing. Samples o f both s t a n d a r d and modified HastellQy N Were a1WaY.S i r t excellent p h y s i c a l COnditiozl With o n l y a s l i g h t amount of d i s c o l o r a t i o n , ' 39149'5~16 and visual m e t a l l o g r a p h i c examination f a i l e d t o r e v e a l any changes that were a t t r i b u t a b l e t o c ~ r r o s i o n . (As d i s c u s s e d i n d e t a i l l a t e r , a s e r i o u s problem w a s rev e a l e d a f t e r examination of t e n s i l e specimens t h a t w e r e s t r e s s e d t o failure; however, t h e cause o f t h e problem i s n o t c o n s i d e r e d to b e 08 cOKrOsion.

....

C.!i.>

The chromium g r a d i e n t s i n some of these samples were measured by t h e electronmicroprobe a n a l y z e r , and t h e w o r s t case w a s a g r a d i e n t t h a t Standard m e t a l l o g r a p h i c ' extended about 0.8 mil i n t o the material. CQl80 m a g n i f i c a t i o n ) examination of several t u b e s from t h e c o l d e s t p a r t of t h e heat exchanger r e v e a l e d o n l y d e p o s i t s of a few iron c r y s t a l s . &..

The MSRE coolant circuit c o n t a i n e d EiF-BeF, (66-34 mole X> at 558-650"C f o r a b o u t 26,800 hours. The chromium c o n t e n t of t h e c o o l a n t salt d i d n o t change measurably d u r i n g this time, and no chromium d e p l e t i o n c o d d b e d e t e c t e d by m e t a l l o g r a p h i c methods. e x p e r i e n c e confirmed t h e b a s i c c o m p a t i b i l i t y of fuel s a l t , HastePPoy M, and g r a p h i t e that had been i n d i c a t e d by many tests. 2.3.2.5.4

R a d i a t i o n embrittlement

ny of t h e s u r v e i l l a n c e samples from the MSRE were s & j e c t e d t o meehani e a l p r o p e r t y tests that c o n f i r ~ ~the d previous k n ~ w l e d g et h a t H a s t e l l o y N his e m b r i t t l e w e n t i s e d r i t t ~ e dby n e u t r o n i r r a d i a t i o n . 1 3 9 1 4 9 '59 16 o c c u r s only a t e l e v a t e d temperatures and i s due t o helium formation i n the metal; i t is q u i t e u n i v e r s a l among i r o n and n i c k e l base a l l o y s . 18-3 0 The d e g r e e of embrittlement PHI t h e &ERE was equivalent to t h a t noted in samples i r r a d i a t e d in t h e ETR and Q Thus, t h e mechanical p r o p e r t i e s were n o t degraded d i f f e r e n t l y when exposed t o salt t h a n when exposed only t o i n e r t gas, F r a c t u r e s t r a i n was t h e p r o p e r t y of most concern w i t h r e s p e c t t o the MSW. The f r a c t u r e s t r a i n s of some samples from t h e core were only 0.5% i n c r e e p tests a t l200"F, i n c o n t r a s t t o strains of 310% ~ Q u Pnirradiated samples Sumeillance specimens exposed alon s i d e sf t h e r e a c t o r vessel The c o n t r o l rod t h h b l e s w e r e a t lower f l u x had s t r a i n s of o n l y 2 % . 1 5 3 1 6 t h e only metal i n t h e core, and they w e r e s u b j e c t e d to small compressive force^^ The vessel w a s s u b j e c t e d t o v e r y sml1 stresses. Consequently, t h e r a t h e r l o w s t r a i n limits were ot exceeded and t h e system o p e r a t e d w i t h o u t f a i l u r e from r a d i a t i o n d a a

k...

2-13 The e n t i r e area of t h e d e s i g n of c ~ m p o n e n t sf o r high temperature s e r v i c e i s r e c e i v i n g c o n s i d e r a b l e a t t e n t i o n . Although t h e s t r a i n l i m i t s have n o t been f i r m l y e s t a b l i s h e d , i t seem l i k e l y t h a t l o c a l s t r a i n s above t h o s e allowed by s t a n d a r d Hastelloy N m u s t b e a c c o m d a t e d .

2.3.2.5.5

Grain-boundary c r a c k s

A second problem noted w i t h H a s t e l l o y N removed from t h e MSRE w a s that shallow i n t e r g r a n u l a r cracks formed i n s u r v e i l l a n c e samples and on a l l o t h e r s u r f a c e s i n c o n t a c t w i t h t h e f u e l . 3-17 ~ h e s ec r a c k s g e n e r a l l y extended t o d e p t h s o f o n l y a b o u t 5 mils, b u t some w e r e as deep as 1 3 m i l s Tn p a r t s removed from t h e pump bowl. Although r e c o g n i z a b l e i n metallog r a p h i c s e c t i o n s of some material removed from the M S E , more were v i s i b l e and t h e y w e r e opened much wider a f t e r b e i n g s t r a i n e d i n the h o t cell. Cracks found a f t e r s t r a i n i n g material t h a t had been exposed i n t h e c o r e were no more p e r v a s i v e o r deeper than t h o s e i n t h e heat-exchanger t u b e s , which had been exposed t o i n s i g n i f i c a n t n e u t r o n f l u x . By c o n t r o l l e d d i s s o l u t i o n of several samples, a number of f i s s i o n p r o d u c t s were found w i t h i n t h e material t o a d e p t h of several m i l s . This s u g g e s t e d t h a t the c r a c k i n g w a s caused by d i f f u s i o n o f f i s s i o n p r o d u c t s i n t h e g r a i n boundaries - p a r t i c u l a r l y t e l l u r i u m , which w a s found a t t h e h i g h e s t concentration.

’

2.3.3

S t a t u s of development

2 3 .% I Generalized corrosion e

,.=,

.....

.... . . d

...., .:%y

..... , .:::* ...

H a a t e l l s y N ( b o t h s t a n d a r d and m o d i f i e d ) has been shown i n t h e MSRE, o t h e r i n - p i l e testss and l a r g e number of o u t - o f - p i l e loops t o have excellent c o r r o s i o n r e s i s t a n c e i n s a l t s c o n t a i n i n g LiF, BeF4, ThFq9 and UPq.’ r 2 S 7 ’ 31 This e x t e n s i v e e x p e r i e n c e confirms t h e b e h a v i o r t h a t would be p r e d i c t e d from d i f f u s i o n c a l c u l a t i o n s . Titanium f o m a s t a b l e f l u o r i d e , and the addition of this element to Hastelloy M c s u f d increase t h e c o r r o s i o n rate. However, d i f f u s i o n measurements have shown that Ti d i f f u s e s more slowly i n Wasrelloy N t h a n C r and t h a t i t would l i k e l y c o n t r i b u t e very l i t t l e t o t h e c o r r o s i o n rate. S e v e r a l c o r r o s i o n l o o p s c o n t a i n i n g i n s e r t samples of Ti-modified H a s t e l l s y N confirm t h a t t h e modified a l l o y does n o t c o r r o d e more r a p i d l y t h a n s t a n d a r d HasteLloy N . I n f a c t , the lower iron c o n t e n t (Table 2.1) causes t h e modifed a l l o y t o have a lower c o r r o s i o n rate. Corrosion s t u d i e s with a proposed c o o l a n t s a l t s sodium f l u o r o b s r a t e , have been more limited.32-35 Pour thermal convection l o o p s and two pumped systems have been o p e r a t e d f o r a t o t a l test t i m e of about 140,000 hr. T h i s e x p e r i e n c e reveals t h a t t h e f b u o r o b o r a t e salt a b s o r b s m o i s t u r e q u i t e r e a d i l y , w i t h a t t e n d a n t g e n e r a l i z e d c o r r o s i o n . On o c c a s i o n s when l e a k s developed, t h e c o r r o s i o n rate h a s i n c r e a s e d and them d e c r e a s e d as the i m p r t r i t i ~were ~ exhausted. During these periods of high esrrssion a11 components sf t h e a l l o y were removed uniformly from t h e hot l e g and

2-14

Screening experiments have s h m that iron-base materials such as %he a u s t e n i t i c s t a i n l e s s steels and nickel-base a l l o y s c o n t a i n i n g more Gr than H a s t e l l o y Ea have improved r e s i s t a n c e t o f i s s i o n - p r o d u c t cracking. For t h i s reasonp they may be considered as a l t e r n a t e c a n d i d a t e s for use i n the primary c i r c u i t if Mastelloy N cannot b e modified to obtain sufficient resistance.

The corrosion behavior of several o t h e r nickel-base a13bogs was i n v e s t i gated i n s c r e e n i n g tests in t h e a i r c r a f t p ~ o p u l ~ i o pwr o ptC3pOSed Ser%piCe teDIpeKEitUre W a s 1580°F a d TilOSt Of the not considered f u ~ t h ebecause ~ i n t e s t s a t t h a t temperature large mounts of chromtura were removed, with formation of v o i d s i n the h o t regions of tern l o o p s and deposition of c ~ r o m ~cm r y s t a l s in the cola regions. Inconel 668 received more s t u d y tham any a l l o y b e s i d e s HastelPoy N , and the evaluation program on it invo%ved several thermal convection loops and 9 f o r c e d convection loops that o p e r a t e d f o r a total of 79,308 hK.7 !dthOU&l the COrp%OSiOH1 r E 5 S i S t ~ l T c @Of HflCOHleb 600 w a s n o t as good as that of Hastelkoy N, a t %BR temperatures the rates were sometimes Pow enough to be sf interest. For example, one I n e o n e l 400 h o p o p e r a t e d a t a peak temperature of 1256°F for hteKgIPZDIUhr pelaetrathX3 sf 1.5 dh. penetlPa% our c u r r e n t s t a n d a r d s , b u t was only slbigkt%y higher than that observed t e l l s y E9 t e s t e d $72 s a l t of comparable purity. Thus9 it is likely t h a t an alloy c o n t a i n i n g 15.2 chromim ( e . g e l I n c o n e l 480) would have a c c e p t a b l e C O K ~ O S ~ O rZe~s i s t a n c e a t 1208°F o r less.

2-15

at less severe conditfsns. However, the oxidation state can be controlled closely enough for the salt to never beeme t h i s oxfdizing to e i t h e r material.

Iron-base alloys are not compatible with s o d i m flusroborate since i r o n seems to be attacked as readily as chromium. The use of d u p l e x tubing in the primary heat ~ C R Z U I ~ ~would PS likely be required if i r o n base alloys were Used f O P ConstruCthg the p r h a r y C i r e U i t . 2.3.3.2

Irradiation mbrittlement

The peak fast fluence at the i n s i d e surface of the MSBW reactor vessel will be sf the order sf I O 2 ' n e u t r s n s / a 2 , which is too l o w to cause detectable swelling and void formation in the However, the peak theanal fluence of 5 x neutrons/cm2 is great enough to produce significant mounts of k e ~ u r n , about 5 ppm from residua^ and p o s s i b l y another 1608 t o 200 ppm by transmutations a v o ~ v i f t gntckel. 3 7 In standard Eastelloy N the helium would reduce the grain boundary cohesion and increase the tendency for grain boundary fracture, with the result that the fracture s t a i n s at elevated temperatures becme

quite Bow. The approach to combating abmittHement is to add elements such as titania, hafnium, Z ~ K C ~ ~ ~and U I ~ D P o b i that t ~ ~ promote the formation of f i n e l y d i s p e r s e d MC type carbides. 3 8 These carbides produce nmerous interfaces that t r a p the helium rather than allowing it ts be swept into the grain boundaries.

All of the carbide-forming elements are beneficial 2n hprovfng the fracture s t r a i n , but there are s e v e ~ a lpractical reasons why titanium and niobium are nore desirable. Zirconium has been found t~ cause weld netal crackin in coneewtratisns as low as 0.05% and for t h i s reason, would be a very undesirable a l l o y h g addition.39 li%afnimcauses weld metal cracking at concentrations of about 0 . 7 X , but the greatest p r o b l m with using t h i s elment is its very high chemical reactivity.

%II STM~I IabOKatsry ~ W f t s h % e hthe metal OII.IY contacts a ~ater-c~~lbed copper mold, the f n a f n i ~is ~ ~present ~ d e s i r a b l e f i ~ ~ l dispersed ly carbides. In esmereial melting practices where the malt contacts a refractory crucible, the hafnium is prbariPy present as a coarse compound. This f f k e l y occurs because hafnium is sufficiently reacttve chemically t o pCXhc@ the OX$deS and Other COllkpOUXldS in %he %fefractOq CrUCkbh. The COZkrSe ~ O I E p O U I l d s dQ slat r e S U % t %n good mechallfcal prOlpertieS after irradiation. We have found that niobium additions alone do not bprove resistance t o irradiation embrittlement, but they are beneficial when ow ever, b o t h niobium and titanium form b r i t t l e titanfum is present.38 (Ti, Nb) cmpsunds and their total concentration must be fina5ted. Ni3 Since titanium seems t~ be the most effective s2ngle additive in h p r o v h g the resistance to frradiation, attention has been concentrated on alloys ~ W c hc o n t a b about 2X titanium. ~

... ..... ..=

2-16

The mount of t i t a n i u m required f o r good r e s i s t a n c e t o neutron i r r a d t a t i m depends strongly upon the s e r v i c e temperature.3 8 ~t 1 2 0 0 ~alloys ~ d t h 0.5% t i t a n i ~have fracture strains of above 4%$ but a t an i r r a d i ation temperature of 14QQ"F, 2% t i t a n i u m i s required to o b t a i n the same properties. D P r e c t transmission electron microscope observations have s h m that this i s due t o the fine earbide becoming less stabbe, and I D O K ~ t i t a n i u m being necessary f o r s t a b i l i z a t i o n as the s e r v i c e temperature i s 2ncmeased. Several lOdB-lb commercial melts c o n t a i ~ ~ h -1.5 ~ g to 2.1% titanium were procured frm t h r e e vendors and evaluated. The mechanical p r o p e r t i e s and w e l d a b f l i t y of t h e u n i r r a d i a t e d m e l t s are s u p e r i o r to those of standard Eastelloy W. The compatibility of titanium-containing alloys with f u e l salt has been i n v e s t i g a t e d using specimens of modified alloys fn n a t u r a l c i r c u l a t i o n l o o p s , and some specimens were MSW core. Although t h e titanium i s reactive with the s a l t , i t d i f f u s e s less rapidly than the chrmim and does n o t contrtbute d e t e c t a b l y to the ~ o ~ r ~ ~ rate.40 i o n Hastellcey N modified by t h e a d d i t i o n of about 2% titaninm has t h u s been found t o be adequately r e s i s t a n t t o radiatPon a t I40O0F, t o be weldable wtthout unusual d f f f i c u l t y , and t o be free of added corrosion problems. Commercial-scale production of this a l l o y must be demonstrated, but. t h e a l l o y conposition does not appear to be one t h a t w5ll p r e s e n t p r o b l m s . l o r a t o r y i r r a d i a t i o n s t u d i e s have shorn t h a t Inconel 600 and a l l o t h e r nickel-base alloys are m b r i t t l e d at elevated temperatures by thermal neutron ir~adiatisn.l8~19,21,22~28-3QT I I ~ f r a c t u r e s t r a i n s vary f o r different a l l o y s , irradiation, a d test c o n d i t i o n s . However, t h e f r a c t u r e s t r a i n s will l i k e l y be too low for a l l o y s such as Inconel 686 without c l o s e r c o n t r o l s on chemistry, grain s i z e , and o t h e r factors.

The s t a i n l e s s steels are also a b r i t t l e d by i r r a d i a t i o n , but it i s poss i b l e that t h e f r a c t u r e s t r a i n s under HSBB s e r v i c e c o n d i t i o n s will be adequate.41 If n o t , s i g n t f i c a n t improvements have been made %n types 304 and 316 s t a i n l e s s steel by c o n t r o l l i n g the grain s i z e o r a l t e r i n g the csmposltisn (such as adding small m o u n t s sf ri),b2 2.3.3.3

I n t e r g r a n u l a r cracking

Cracks were formed on a l l s ~ l ~ f a c eexposed s t o fuel s a l t .

I P r a d k t i o R of the metal did not seem to be a factor, s i n c e the cracks were equally s e v e r e tri components that were i r r a d i a t e d and u n t r r a a i a t e d =

.... <.:.=

2-19

Some cracks were v i s i b l e i n polished s e c t i o n s from some cowportents ( p a r t i c u l a r l y t h e h e a t exchanger) when they w e r e removed from s e r v i c e , b u t deformation a t ambient temperature w a s required t o make most v i s i b l e .

%he material removed from t h e MSKE had been heated and exposed

t o f i s s i o n products for t i m e s ranging from 2500 t o 25,000 h r . Although t h e frequemcy of cracks increased with t i m e , t h e maximum depth d i d not i n c r e a s e d e t e c t a b l y . S i m i l a r intergramular cracks have not been produced by corrosion. To determine whether corrosion could be t h e cause, t h e salt i n one f u e l - s a l t loop w a s made q u i t e o x i d i z i n g by adding FeF2. S e l e c t i v e i n r e g r a n u l a r a t t a c k occurred, b u t t h e a t t a c k w a s very shallow and t h e corroded g r a i n boundaries did not open f u r t h e r during s t r a i n i n g . The second, a d most convincing evidence t h a t corrosion (chromium d e p l e t i o n ) d-bd not cause t h e cracks came d i r e c t l y from examination of M % E samples. Although chromium d e p l e t i o n could n o t b e d e t e c t e d i n samples from t h e h e a t exchanger and in a s e c t i o n of t h e c o n t r o l rod thimble t h a t w a s under a spacer s l e e v e , t h e s e samples were cracked as s e v e r e l y as those (e.g., t h e b a r e c o n t r o l rod thimble i n whish chromium d e p l e t i o n w a s d e t e c t a b l e . Thus, i t seem u n l i k e l y t h a t chromium d e p l e t i o n alone can account for the observed cracktng

The next p o s s i b l e mechanism considered w a s t h a t one o r s e v e ~ a lelements d i f f u s e d into t h e material p r e f e r e n t i a l l y along t h e g r a i n boundaries

.... fa

, &

and degraded them i n some waye The process r e s p o n s i b l e f o r the crackirng could be (1) t h e formation of a compound t h a t i s very b r i t t l e , ( 2 ) f o r mation of low-melting phases along t h e g r a i n boundaries t h a t become l i q u i d a t o p e r a t i n g temperature, o r (3) a change i n composition along t h e grab boundaries s o t h a t they a%@ still s o l i d b u t very weak. %he f i r s t and t h i r d mechanisms would r e q u i r e some deformation t o form t h e cracks, b u t the second mechanism would not r e q u i r e s t r a i n , and samples could have cracks p r e s e n t b e f o r e postoperation deformation. The r e s u l t s sf a n u d e r of tests ~ R C Idata from t h e ~ i t e r a t u r suggested e ~ ~ ~ ~ strongly ~ t h a t t h e i n t e r g r a n u l a r a t t a c k is caused by t h e inward d i f f u s i o n of elements of t h e s u l f u r , selenium, t e l l u r i u m family w i t h t e l l u r i u m having t h e most adverse e f f e c t , and subsequent s t u d i e s w e r e concentrated on t e l l u r i u m . Since t h e s e elements a l l behave s i m i l a r l y , an understmd5ng of how t e l l u r i u m causes c r a c k h g should l e a d t o an understanding of t h e behaviour of t h e o t h e r elements.

Numerous l a b o r a t o r y experiments were run t h a t demonstrate very c l e a r l y t h a t small amounts of t e l l u r i u m w i l l cause i n t e r g r a n u l a r cracking i n Hastelloy N. These experiments include: (1) t h e measurement of g r a i n boundary and bulk d i f f u s i o n c o e f f i c i e n t s of t e l l u r i u m i n Hastelloy N , type 304 s t a i n l e s s s t e e l , and n i c k e l ; (2) exposure of numerous materials t o e l e c t r o - o r vapor-plated t e l l u r i u m w i t h subsequent s t r a i n i n g and metallographic examination; ( 3 ) tube b u r s t specimens of Hastelloy N and type 304 s t a i n l e s s s t e e l e l e c t r o p l a t e d with t e l l u r l u m and s t r e s s e d in s a l t ; ( 4 ) creep t e s t s of Hastellog. N, type 304 s t a i n l e s s s t e e l , n i c k e l ,

2-18

and Incowel 600 ita inert as-tellurim vapor mviroments; (5) strain cycle e x p e r b e n t s of Hastelloy E9 electroplated with t e l l u r i m to det e r n h e crack propagation nates; and (6) mechanical property testa on allays containing mall m o u n t s of fission p r o d u c t s . The d i f f u s i o n rate of tellurium i n t o Hastellay Es was measured. Samples w t t t a 1 2 7 ~ edeposited an the s u r f a c e were annealed for ~ O O Ohr at 650 and 960°C. At $58'6 t h e penetratfon was so shallow t h a t t h e lapping technique used d5.d not give very r e l i a b l e values, but accurate results were obtained at 760QC and the diffusion coefficient fn the bulk mater i a l w a s 1.01 x 4 '6 1 cm2/secf about e q u i v a l e n t to that of chromium at 650°C. The penet%atiOIl p r o f i l e s also W e r e Used t o o b t a i n the pT32dUct of the grab boundary w i d t h a d the grain boundary diffusion coeff%cient, and measured quantities were then used w i t h the Fisher naodel45 to c m ain boundary p e n e t r a t i o n . On t h i s basis9 the maarxbm penetzatlsn 0% t e f h r i m in an HSBR at $60°C would be 8 mils in 38 years. The less acc~ratee x p e r h e n t a l v a l u e s ~ b t a i n e da t 65QeC were lased to estimate that t e l l u r i u m should Ilave penetrated the grain boundaries to a depth of 2 to 3 ana the penetration of MSBR operating at 656°C for 30 y-r should be about 4 mils. The relatively h W SenSi%iVity Of the pefsetrat%on d e p t h t Q the t b e is due to the VWiEibion With t h e to t h e one-fUUPth pomr for g r a b bOUlldary diffUsiOn cmpared with the one-half power for bulk diffusion, These computed depths sf penetration are quite acceptable, but several factors can alter the results, hence they cannot be taken quantitatively.

2-19 which are of i n t e r e s t for MSR's are shown i n Table 2 . 3 . 3 . 3 . 1 . Of t h e s e , titanium-modified H a s t e l l o y N m y b e s u f f i c i e n t l y r e s i s t a n t t o a t t a c k , and no a t t a c k has been observed f o r t h e remaining materials. It i s b e l i e v e d t h a t a s a t i s f a c t o r y alloy c a n b e o b t a i n e d from one of the first t h r e e c a t e g o r i e s , and i t i s known that t h e s e materials w i l l a l s o have a d e q u a t e r e s i s t a n c e t o n e u t r o n e m b r i t t l e w e n t and g e n e r a l corrosion.

If a h i g h e r chromium a l l o y were used ( e . g . , Income1 600), i t would b e n e c e s s a r y t o t e s t i t s n e u t r o n e m b r i t t l e m e n t c h a r a c t e r i s t i c s and t o develop a d e q u a t e r e s i s t a n c e i f t h i s w e r e n o t p r e s e n t . Neutron e m b r i t t l e ment i n t y p e 304 s t a i n l e s s steel c o n t a i n i n g 8.2% T i i s n o t a problem. Generalized c o r r o s i o n could be a problem w i t h both of t h e l a t t e r materials, and t h e r e a c t o r o u t l e t t e m p e r a t u r e might have t o b e lowered from 1 3 0 " ~ t o l 2 8 O Q F i n t h e ease of s t a i n l e s s steel. ' h e nominal cornp o s i t i o n of t h e material of g r e a t e s t h t e r e s t i s shown i n Table 2 . 3 . 3 . 3 . 2 . The molybdenum and s i l i c o n c o n t e n t s have been d e c r e a s e d from those i n s t a n d a r d H a s t e l l o y N, and 2%;T i has been added t o p r o v i d e r e s i s t a n c e t o n e u t r o n embrittlement. 'khe rare e a r t h s w e r e added i n l o w c o n c e n t r a t i o n s t o p r o v i d e i n c r e a s e d r e s i s t a n c e t o i n t e r g r a n u l a r a t t a c k by t e l l u r i u m .

& & .!

Tests w i l l b e c a r r i e d o u t t o d e t e r d n e b a s i c i n f o r m t i o n r e l a t e d t o chemical r e a c t i o n s between Hastelloy IN, t e l l u r i u m , and s a l t . '%he ~ e a e t i o np r o d u c t s w i l l b e i d e n t i f i e d and the r a t e c o n s t a n t s a s s o c i a t e d S w i l l be irradiated w i t h their formation will b e measured, Q ~ K ~ O U alloys to d e t e r d ~ et h e i r r e s i s t a n c e t o i r r a d i a t i o n embrittlement. An important v a r i a b l e i n t h e s e s t u d i e s w i l l be t h e a l l o y co~nposition. Emphasis will b e p l a c e d on a modified H a s t e l l o y M having a b a s e cowpositon of 12% Mo, 7% Ca, 8.85% C, b a l a n c e M i . Additions o f t i t a n i u m up t o 2 X and %are e a r t h f e . g . , Ce, La) up t o 0.02% w i l l b e e v a l u a t e d . The end ~ e s d of t t h i s task should b e t h e s e l e c t i o n of an a l l o y w i t h a d e q u a t e r e s i s t a n c e t o i r r a d i a t i o n e n h r i t t l e m e n t and i n t e r g r a n u l a r c r a c k i n g whfch i s a l s o eompatib%e w i t h t h e s o d i m flusroborate coolant s a l t .

.... < &

2 4.1 e

Obj ective

... ...

The o b j e c t i v e of t h i s t a s k i s t o p i n p o i n t the composition of modified ~ n tf o s r t h in: Subsection 2 . 3 . 1 . H a ~ t e l P ~ gNr t h a t meets t h e r e q ~ f ~ e ~ t set

.... .... .&

2.4.2

Schedule

The schedule f o r work i n Task Group 1.1 i s shown in Table 2.4.2.

2-28

Table 2 . 3 . 3 . 3 1 e

Potential materials for MSBR primary circuit

Ti-Modified k s t e l l s y N (2% Ti> Ti-RE-Modified Hastell~yN (2% Ti -k 0.01 to 0.1% Ce of La) Ti-Nb-Modified Hastelloy Ea (Ti f NBa, Q2W total) Hastellay or Inconel containing ~ 1 6 % Cr

Table 2 . 3 . 3 . 3 . 2 .

NowinaP composition of Hastelloy N

BaP

Bal

0.5

0.2

0.5

0.1

0.0%

0.05

0 -01

(XI

Table 2.4.2.

Schedule f o r work in Task Group 1.1 - Determination ~f a l l o y compositian Fiscal. year

19 77 1.1.1 Procurement of test m a t e r i a l s 1.1.1.1 S m a l l heats with r a r e e a r t h additions 1.1.1.2 10,000 l b heat containing 2% T i 1.1.1.3 Laboratory m e l t s with various Ti-Nb concentrat ions 1.1.2

Basic s t u d i e s on i n t e r a c t i o n of Te with Hastelloy N I n t e r a c t i o n of Hastelloy N with T e vapor 1.1.2.1 1.1.2.2 I n t e r a c t i o n of Hastelloy N with T e i n fuel. salt

1.1.3

E f f e c t s of fission products an mechanical p r o p e r t i e s 1.1.3.1 Creep tests 1.1.3.2 Tube burst tests 1.1.3.3 S t r a i n cycle tests

1.1.4

Thermal convection C O ~ K O S ~ tests Q ~

1.1.5

Forced convection carrosion tests 1.1.5.1 F a - 2 1.1.5.2 FCL-3 1.1.5.3 FCL-4 1.1.5.4 Fa-5

1.1.6

In-reactor f u e l capsule tests 1.1.6.1 TeGen-1 1.1.6.2 TeGen-2 1.1.6.3 TeGen-3 1.1.6.4 TeGen-4 1.1.6.5 TeGen-5 1.1.6.6 TeGen-6

Table

2 4 o 2 (continued) l

mscaa

1.1.7 TrradiatisnEmbrittlement sf HastelloyN P.l.7.1. P.1.7.2 1.1.7.3

1.1.7.4 l.l.7.5

ORIt irradiation af tensile specimens Post ikradiatlsn creep tests Tube burst tests Control creep tests Characterization of microstructure

yea%:

2-23

e r a t i n g fund ~ e q u f r a e n t sfor Task Group 1.1 are summarized in Table and c a p i t a l equipment r e q u l r m e n t s are s m a r i z e d in Table 2.4.3.2.

2.4.3.1,

2.4.4

Facilities

Bldg. 45oos, wnn. T-48 - mis labssratory will house the themal convection loops @I2 loops). ...&

Bldg. 9283-1 - m e forced Convection loops W i 1 1 be located on the operating f l o o r of t h i s building.

Hot Cells - h e c e l l will be used in Blbdg. 3025 for postirradiation ~ ~ e e p testing. S e ~ e ~ ao bt h e r hot cells wIII be used f o r s h o ~ tp e r i o d s of t i m e f o r experiment disassembly, ~ ~ t a l l o g ~ a p hand y , various other ~ ~ p e ~ i m e n t s on i ~ r a d i a t e dmaterials.

2.4.5

Task %,1.lProcurement of test materfals

The test materials to be procured focus on the f u r t h e r evaluation of the effects of additions of t i t a n i u m , rare e a r t h s , and niobPm on the properties of bstellsgr N. me role of t f t a n i m in this a l l o y is reasonably wekH e s t a b l i s h e d , and a 10,800-Pb heat is being procured t o obta2n experPence ow. m e l t i n g and fabrfcation procedures. me a d d i t i o n of rare earths or niobium in combination with titanium is aimed at obtaining hereased resistance to i n t e r g r a n u l a r crackhg. 6w1y these a l l o y s w i l l be prepared u n t i l the e f f e c t s of the better U d e r s t O O d . If the r @ S U l t S frCRB the SI¶E%ll ElgPts E5M33UKag%zsg9 r c i a l melts wfll be procured t o further e v a l u a t e niobium and raBfe-e%Ktk a d d b t h l s .

2-24

Table 2.4.3.1. Operat-Fng fund requirements f o r Task Group 1.1 Determination of alloy composition (costs i n 1QOO d o l l a r s ) F i s c a l year

1.1.1

Procurement of t e s t materials 11 h e a t s w i t h rare e a r t h additions 1.1.1.2 10,000 1b heat c o n t a i n i n g 2% T i 1.1.1.3 Laboratory m e l t s w i t h v a r i o u s Ti-Mb COnCentkations

Sub t o t a l 10 1.1

1.1.2

Basic s t u d i e s on i n t e r a c t i o n of Te with Hastellsy N Interaction of H a s t e l l o y N with Te 1.1.2.1 vapor 1.1.2.2 I n t e r a c t i o n of H a s t e l l o y N with T e i n fuel s a l t

E975

1976

10 15

10 -

I50

25 4

208

__s

1.1.3

Subtotal 1 1 2

404

261

Effects of fission p r o d u c t s on mechanical proper ties 1.1.3.l creep t e a t s 1.1.3.2 Tube burst tests 1.1.3.3 S t r a i n cycle tests

125 EO 0 125

125 50 125

Subtotal 1.1.3

350

300

1.1.4

m e m 1 convection c o r r o s i o n t e s t a

100

3-25

1.1.5

Forced convection eorroeion t e s t s 1.1.5.1 PCL-2 1.1.5.2 FCE-3 1.1.5.3 P a - 4 1.1.5.4 PGL-5

20 5

60 35 20

Subtotal 1.1.5

115

$75

1.1.6 30 90

Subtotal. 1.1.6

$8 85 80

202

250

1977

2-25

Table 2 . 4 . 3 .k (continued)

Fiscal y e a r 1975 1.1.7

I r r a d i a t i o n e m b r i t t l e m a t of Hastelloy E9 1.1.7.1 ORR i r r a d i a t i o n s f t e n s i l e specimens P o s t i r r a d i a t i o n creep tests 1.1.7.2 1.1.7.3 Tube b u r s t tests 1.1.7.4 C o n t r o l c r e e p tests 1.1.7.5 C h a r a c t e r i z a t i o n of m i c r o s t r u c t u r e

65 100

T o t a l o p e r a t i n g funds for Task Group 2.1

Table 2.4.3.2.

1979

120 128 80 80

$0 100 135 ~

S u b t o t a l 1.1.7

1976

162 ~

470

562

1671

1693

- -

C a p i t a l equipment f w d requirements f o r Task Group 1.1 Determination of alloy composition ( c o s t s i n 1000 d o l l a r s )

Fiscal year

1995

1976

properties 1.1.3.1 Creep tests 1.1.3.3 Strain cycle tests

35 36

48 30

1.1.4

T h e r m 1 convection t e a t s

1 .% .5

Forced c i r c u l a t i o n loops 1.1.5.2 FCL-3 1.1.5.3 F a - 4 1.1.5.4 FCL-5

1.1.2

Basis te1lurium i n t e r a c t i o n s t u d i e s

1.1.3

Effects of f i s s i o n products on mechanical

1.1.6

In-reactor capsule t e s t s

T o t a l c a p i t a l equipment funds f o r Task Group 1.1

300

300 3 3

135

563

1977

2-2

Pour %2%-lb come.lp~ia% h e a t s will be procured for e v a l u a t i o n . These heats Will COnSi%%of 0.01 fi.0 8.02% additions Of &, Ea, and NiS€!k EEItal (primarily Ce and La) ts a modified Mastellsy M b a s e c o n t a i n i n g 2% T i . The a l l o y s w i l l be prepared by vacuum induction m e l t h g followed by electroslag remelting and rolling t o l/2-ine-thick plate. n e welda b i l i t y of the f o u r m e l t s w i l l b e determined, and the material will b e used i n a l l portions of Task Group 1.1. 2* 4 5 2 D

Subtask l o 1.1 * 2

n8,ooo-lb c o m r c i a 1 m e l t

A 10,880-lb h e a t of modified Haatelbloy %a c o n t a i n i n g 2% T i will be procured in order t o o b t a i n e x p e r i e n c e with t h e production of a comercia1 h e a t of material which i s b e l i e v e d to b e close i n composition t o a number sf acceptable a l l o y s . This alloy composition has been noted through e ~ p e r i e w ~wei t h several 160-%b heats to have excellent resists~~n~e $0 irradiation rittlement a d b e t t e r resistance to Hntergranaafar fission p r o d u c t cracking than s t a n d a r d Bastellioy N. The l a r g e h e a t will be fabricated i n t o several product f o m s and wPk1 b e u t i l i z e d i n many tasks i n Task Group 1.1.

2.4.5.3

Subtask 1.1.1.3 Laboratory melts having v a r i o u s concentrations

%-Ti

Niobium a d d i t i o n s improve the resistance of Hastellsy N t o intergranular b u t kava very little effect on r e s i s t a n c e t o irradiation e* e n t . me combined use of titanium f o r a f f o r d i n g r e s i s t a n c e to i r r a d i a t i o n e rittlement and niobium for i n c r e a s i n g t h e resistance to t e l l u r i u m i n t e r g r a n u l a r a t t a c k w i l l b e explored. Niobium and t i t a n i u m are a d d i t i v e i n inducin the f a m a t i o n of b r i t t l e gama-prime i n the alloy, hewee they st b e added s p a r i n g l y . About twenty laboratory melts, each weighi about 2 i b 9 w i ~ lbe =de with various additions of titanium and niobium. These alloys w i l l be e v a l u a t e d i n other tasks of Task Group 1.1.

2.4.6

Task 1.1.2 Basic s t u d i e s on i n t e r a c t i o n of tellurium with Hastelloy M

Since a c t u a l r e a c t o r o p e r a t i n conditions represent iBzT extrapolation eXperfEEntal QbS@rVatiOnS, L t i s i m p e r a t i v e that r e a c t i o n s b e unders t o o d rather than t h e i r bates b e h asaisred OV@K a relativelgr Short t i m e period. %%ais t a s k is d i r e c t e d toward u n d e r s t a n d i n g th@ interactions of t e l l u r i m , H a s t e l l o y Ea, and s a l t i n sufficient detail to d e f i n e t h e phenomena which lead t o attack 5.n s t a n d a r d H a s t e l l o y Ea and t o d e t e d n e haw attack i s prevented i n p o t e n t i d materials o f csatstruct5an. Of

2-27

2.4.6.1

... ....

% L ,

... . >&

Subtask P.l.2.1 I n t e r a c t i o n of BasteEloy N w i t h tel%uriePna vapor

T e % P ~ r i mwill be present a8 t h e mta%d h e r , Tezp and in s n l E e ~ .quantities as the monomer, '$e, and/or in a reduced s t a t e under the reducing conditions t h a t will be p r e s e n ~in t h e KSBR primary c i r s u f f . Thus, studies where HasteEloy EJ is e q o s e d to small mounts of tellurium vapor are believed t o simulate reactor operating coadftions closely enough to be valuable. Hastelloy N (modified and standard) w i l l be eXpQ§ed tel%UPiUllI VapSl- and t h e PeaCted Eietal Will be Used to idefatifgP reaction products, evaluate effects ow mechanical p r o p e r t i e s , and determine reaction kinetics. Variables s t u d i e d will be t e l l u r i ~ concentration, ~i~ temperature, t i m e , and alloy composition. Auger s p e c t ~ ~ s c o p yelectrsn, microscopy, and x-ray d i f f r a c t i o n w i l l be wed to identify ~ e a ~ t i ~ ~ l products. some samples will be defamed at ambient temperature after exposure t o t e 1 3 b ~ ~ i u ~Samples l. will a l s o be sectioned m d viewed ~ ~ e t ~ i l l ~ g r a p h i ~to a l ldetermine y the extent o f intergranular C K % I C ~ ~ H ~ ~ . 2.4.6.2

Subtask 1.1.2.2 i n fuel s a l t

Interaction of Hastelllsy 65 with tellsnrieaaaa

,..m

2.4.7 *$k<

*a,....

...

($<&

... ....

Task 1.1.3

Effects of f i s s i o n products on mechanical

plroperties

Review of the availab1e iwfomatisw of the effects of fPssion product elements on t h e mechanical properties of HastelPoy ET i n d i c a t e s that tellurium produces by far the largest effect; ~ C W ~ V ~ some K , work wlll be continued on otheb- elements to ensure that they do not also have adverse effects which could be important mder some cond%tions. Several alloys have been prepared which contain smll acaunts of fission product elements, but most of the t e s t a will involve mdoped alloys that will be stressed while a l s o being exposed to a t e l l u r f m - c o n t a i n i n g environment.

2.4.7.1

Subtask l.l.3.l

Creep t e s t s

... . . . . . y

...

I,..

Small h e a t s of Hastellsy N containing 0.01% Se, Te, Sr, Tc, Ru, Sw, and Sb have been prepared previously. These materials will be tested under creep conditions to determine how these elements influence the tendency for crack fornation durin creep t e s t s .

2-28

Creep tests of s t a n d a r d and modified Hastelloy N specimens w i l l b e r u n in s a l t - t e l l u r i u m enviroments to determine how t h e tendency to form i n t e r g r a n u l a r cracks varies w i t h t e s t c o n d i t i o n s and metal composition. Effects of teHBurim on c r e e p b e h a v i o r will also be e v a l u a t e d . About 4 creep machines ~ 5 t hsalt chambers will b e used i n t h i s work.

2.4.7.2

Subtask 1 . l . 3 . 2

Tube b u r s t tests

These t e s t s will impose a l t e r n a t i n g s t r a i n s on a tubular s a m p l e while

t h e o u t s i d e s u r f a c e of the sample i s exposed to salt contai~ring tellurium. This c o n d i t i o n w i l l be similar t o t h a t experienced by a h e a t exchanger exposed to temperature transients. The t i m e r e q u i r e d f o r cracks t~ propagate through the t u b e w a l l will be determined as a funct i o n of a l l o y composition, ~ o n ~ e n t ~ a tof i ~tellurium, n strain l i m i t s , and temperature. F i v e s t r a i n cycle machines will be used f o r t h i s work. 2.4.8

Task 1.1.4

k..

Thema1 c o n ~ e c t i ~cno r r o s i o n tests

THaermal convection Poops will be o p e r a t e d t o s t u d y the corrosion of modi f i e d N a s t e l l o y E% i n f u e l s a l t . A t b e a s t two l o o p s w i l l be c o n s t ~ u ~ t e d of s t a n d a r d H a s t e l l o y N , and small coupons of t h e modified a l l o y s w i l l be i n s e r t e d i n t h e l o o p f a r corrosion measurements. men t u b i n g becomes a v a i l a b l e from the large 2% Ti-ltasdified h e a t , a e n t i r e loop will be f a b r i c a t e d from t h i s material. These loops w i l l be equipped with e l e c t r o chemical probes f o r measuring the ~ 3 * / ~ 4 +ratio and t h e c o n c e n t r a t i o n s of Pe, Cr, and N i in t h e salt. Loops of a u s t e n i t i c s t a i n l e s s s t e e l and h C Q H l e l 601 W i l l be OpePat@d to debexllBh@ %he COPPOSiSHn rates f o r Wt62rid.S having c f m r o m i ~csnsentrations above t h a t of Hastellsy N e At b e a s t m e B a s t e l l o y N loop containing f u e l salt will b e used t o determine the beh a v i o r a€ tellurium i n a flowing system having a t e m p e r a t u r e g r a d i e n t . Two Hastelloy Ea loops w i l l be w e d t o study t h e c o m p a t i b i l i t y of Hastellsy M with t h e c o o l a n t salt. I n s e r t samples of modified Hastelloy N will be 62XpoSed i n t h i s ISOp.

k.2

k.L

2-29

2.4.9

:.a

Task 1.1.5

Forced convection corrosion tests

Thermal convection ~ S O ~ are S a r e l a t i v e l y inexpensive method f o r d e t e r mining c o r r o s i o n behavior. However, t h e s a l t flow v e l o c i t y i n a thermal convection loop is only a few f e e t p e r minute as cmpared w i t h v e l o c i t i e s up t o 20 ft p e r second t h a t w i l l be p r e s e n t 5x1 an MSBR. These higher v e l o c i t i e s can i n c r e a s e the c o r r o s i o n rate markedly over t h a t observed i n thermal convection loops a t t h e lower v e l o c i t i e s . Thus, some corros i o n t e s t i n g must b e done in pumped systems a t r e a l i s t i c flow rates. A versatile forced convection l o o p f a c i l i t y of near-standard design has been developed f o r matertal tests of this type. Work in forced convect i o n f a e i l i t d e s a s s o c i a t e d with t h i s t a s k (designated PCL-2, -3, - 4 , and -5) i s discussed in more d e t a i l i n t h e following secti~ns.

2.4.9.1

Subtask 1.1.5.1

FCL-2

Portions of t h i s f a c i l i t y which c o n t a c t molten s a l t were esnstructed of standard Hastelloy N and t h e f a c i l i t y w a s operated f o r 7,080 hours with t h e sodium f l u o r o b s r a t e coolant s a l t . 'Pke loop w a s modified i n l a t e FY 1974 t o allow c i r c u l a t i o n of f u e l salt. This l ~ ~ designed p , specifically f o r materials t e s t i n g , h a s a s p e c i a l pump designed to give v a r i a b l e pumping speeds. T e s t samples are l o c a t e d a t t h r e e locatioms which can be operated a t d i f f e r e n t temperatures. The samples can be removed by stopping t h e pump and m e l t h g a f r e e z e v a l v e a t each l o c a t i o n . The flow passage geometries are such t h a t t h e s u r f a c e v e l o c i t i e s a t t h e t e s t coupons vary f r ~ m10 t o 20 f p s . This loop w i l l be used p r i m a r i l y f o r studying t e l l u r i u m t r a n s p o r t i n a flowing system having a temperature g r a d i e n t . Two o b j e c t i v e s that must be a e c m p l i s k e d b e f o r e t h e loop can be operated as d e s i r e d are (a) develspment of on-line a n a l y t i c a l technique t o determine t h e ~ 3 + / ~ 4 r*a t i o ~ i ~ d tellurium-ion c o n c e n t r a t i o n i n MSBR f u e l s a l t (see Subtask %.1.1.1), and (b) measurement of t h e base-line corrosion rate of Haetelloy N under t h e conditfons t o be used f o r t h e t e l l u r i u m t r a n s p o r t s t u d i e s . Development work i n both 0% t h e s e areas is in p r o g r e s s , and t e l l u r i u m will be added t o t h e system toward t h e end of EY 1975. 2.4.9.2

Subtask 1.1.5.2

FCL-3

This f a c i l i t y will be of t h e same b a s i c design as FCL-2, but some d e s i g n

9.:.u

improvements w i l l be made. A l l p a r t s of t h e f a c i l i t y which c o n t a c t s a l t w i l l be f a b r i c a t e d from t h e PO,OQO-lb h e a t of 2% Ti-modified Hastelboy M. This f a c i l i t y will be used p r i m a r i l y t o study t h e c o r r o s i o n c h a r a c t e r i s t i c s of t h e modffied a l l o y i n f u e l s a l t . Work w i l l begin on t h e f a c i l i t y e a r l y i n FY 1975 and t h e system should be ffl o p e r a t i o n before mid FY 1976.

2-30

2.4,9.3

Subtask 1.1.5.3

FCL-4

2.4.9.4

Subtask I.l.5.4

FCL-5

2.4.18

Task 1.1.6

In-reactor fueled capsule tests

erimemts have shorn that b t e r ranular cracking quite similar t o that noted in the MS oduced in t h e l a b o r a t o r y by =posure of standard HastelPsy N to olmts of tellurium. n u s , laboratory experiments can be used ing t e s t s , but SOEE h - r e a c t ~fueled ~ tests will be necessary as proof tests. Sma%L (Q-Jl/2 5n- d i m ) tubes w 5 l l be p a r t i d l y filled with f u e l salt and irradiated h the om. me ffasile cO%ate.H88: and irKadiatiOn t h e d l f be Chosen to pHodUC@ the desired ounts of fission products and alley expssure internal. After irradfaonp,the f u e l pins will be sectioned and some portions will be defamed to open intergranular cracks, while o t h e ~s t r a i n e d and unstrained sections dil be viewea meta ograpkfcally to deternine whether cracks were fsmed. S a p l e s will be mined from both the l i q u i d and vapor portions of the fuel tubes. In-reactor fuelbed capsule t e s t s assoclated w5th t h i s task (designated T e G r a - l , -2, -3, - 4 , -5, m d -6) are dfssussed in greater detail in the fsllowing sections.

I n - r e a ~ t ocapsule ~ TeGen-l will be irradiated for l cycle (CU.00 hr) in poolaide facility at $0O0@. n e 2 3 % f u e l loading was chosen suck t h a t the mount sf te u r i m %a%aich w i l l be produced is equivalent to that produced 5r-l the MS drarUg its entire operation. me fuel terials are StandaPd astelloy N, type 304 stainless steel, and Inconel 601.

2-31

2.4.10.2

Subtask 1.1.6.2

TaGen-2

2.4.18.3

Subtask 1.1.6.3

TeGm-3

2.4.10.4

Subtask 1.1.6.4

TeGen-4

..... &

... ....

<S&

.... &

....

.... a

7.m

"he purpose of this experheant w i l 1 be t o evaluate the cracking tendencies ~f modified c m p o s i t i o n s of Haste1lo-j N under different eondftisns. me design w i l l be S ~ I I M to~TeGen-2, P and the operating t i m e w i l l be 6 cycles (~$600hr). The most attractive alloys available d 1 1 be included in t h i s experhefat, and i t s purpose w i l l be to evaluate the resistance sf these ~ ~ & ~ k d to . sfntergranular crackfng over long periods of time. Subtask 1.1.6.5

2.4.10.5

TeGen-5

The purpose of this experhent w i l l be t o evaluate the cracking tendencies of modified c m p o s i t i o n s of k s t e l l s y N under d i f f e r e n t conditions. The design d E P be similar t o TeGeza-2, and the materials and operatin d i t i o n s dl1 be selected ow the basis of results frm t h e development program

Subtask 1.1.6.6

2.4.10.6

TeQn-6

The purpose of th%s e x p e r h e a t will be to evaluate the crackhg tendencies of modified c ositions of Bastelloy N under different conditio design wfll b h i l a r to TeGen-2, and the materials glad o p e r a t i ditions w i l l be selected on the basis of results from the development p r o g r *~

2.4.11 .... :&

...A

Task 1.1.7

I r r a d f a t i s n a b r i t t l e m e n t of H a s t e l l o y ~

kpssure for 1 cycle (ll00 hr) fn the p s s l s i d e facil.ity of the is sufficient t o trmmute about half of the 1% w o m l f y present in stelloy kJ to He- This is adequate @xposurefor evaluation relative to perfomanee fn an HSBR. S p e c h a s suitable f o r tensile tests Fd11 be irradiated at controlled tmperatures after

2-32

w i l l be removed from the i r r a d i a t i o n capsule and subjected to postirradiation creep t e a t s . Creep d a t a will be recorded i n a manner such t h a t adequate i n f o m a t i o n will be a v a i l a b l e t o assess the effects of i r r a d i a t i o n on creep behavior, t h e stress-rupture behavior, and t h e f r a c t u r e s t r a i n . Creep t e s t a will a l s o be run on ranirradiated specimens. Tkese tests w i l l a P h w one t o d i s t i n g u i s h the e f f e c t s of t h e m 1 treatment h i s t o r y and i r r a d i a t i o n .

Microstructure i s very imporant i n determining the mechanical p r o p e r t i e s of modified H a s t e l l o y N , particularly i n the i r r a d i a t e d condition. The microstructure w i l l be characterized by s e v e r a l e l e c t ~ oo p~t i c techniques. F a c i l i t i e s exist for the e x m i n a t i o n of both u i r r a d i a t e d and i r r a d i a t e d samples

2.4.11.1

Subtask l . l . 7 . l

om irradiation of tensile s p e c h e n s

The various h e a t s of modified Hastell~grN w i l l be irradiated i n the O M to Study t h e i r eElb.k-ittlel4ESlt dekril7.g theX3d neUtoR %IX%diatiOnlda helium formation r e s u l t i n g from the t r a ~ ~ ~ ~ . ~ ~ uoft a t i o amd n nfckel. The experiments will n o m l l g r b e operated f o r 1 cycle t o a peak t h e m 1 fltaence of 3 x 10'0 weutrons/em2. ~ r r a d i a t i o ntemperature is an important v a r i a b l e and will be varied from 1050 to 1400°F. The c u r r e n t design for this experiment c o n s i s t s of 32 indfvidually-heated positions, each cont a i n i n g 2 o r 3 specimens. About s i x experiments of t h i s type will be run in t h i s subtask. 2.4.11.2

Subtask 1.1.7.2

P o s t i r r a d i a t i o n creep t e s t s

'%he samples i r r a d i a t e d i n Subtask l . l . 7 . l

& r i l l be ~ ~ e tee spt e d t o determine the influence of Brraddation on the nechanical p r o p e r t i e s . The samples w i l l be q u i t e r a d i ~ a c t i v eand these tests will be performed using creep machines i n t h e h o t cells. Twelve machines currently e x i s t for this purpose. During these t e s t s , stressz time, stpain, and temperature w5ll be recorded. The data will be reduced a n a l y t i c a l l y to strain-time p l o t s and ~ a ~ i o udata s c o r r e l a t i o n s w i l l be developed as required. About 580 t e s t s of this type will b e run.

2.4.lI.3

Subtask 1.1.9.3

Tube burst tests

. .. w.5

2-33 ..... ..-A.... ..

...

$j$$

.... .... ......, ..~. i

i n - r e a c t o r tests are needed. The specimens are p r e s s u r i z e d i n t e r n a l l y t o provide t h e stress. The t i m e t o r u p t u r e i s determined d i r e c t l y during t h e t e s t , and t h e f r a c t u r e s t r a i n is measured a f t e r t h e experiment i s completed. Tubing made from t h e 10,000-lb 2% Ti-modified h e a t w i l l b e a v a i l a b l e l a t e i n FJ! 1975, and t h i s material will be used for this work. Some t u b u l a r material from o t h e r h e a t s w i l l be f a b r i c a t e d and one i n - r e a c t o r tube-burst experiment w i l l be c a r r i e d out.

... .... .....>,

& . . . . I

2.4.11.4 ,:....., ...-

....... &.,.<. i

.... :...... ;.rS

Subtask 1.1.7.4

Control, creep tests

I r r a d i a t i o n experiments s u b j e c t specimens to neutron i r r a d i a t i o n as w e l l as a period of thermal annealing. Each processt can produce changes i n t h e mechanical p r o p e r t i e s , hence t h e e f f e c t s must b e s e p a r a t e d i n o r d e r t o e v a l u a t e t h e importance of each. The t h e m 1 annealing i s apprsximated by annealing u n i r r a d i a t e d specimens a t times and temperatures e q u i v a l e n t t o those encountered by specimens during i r r a d i a t i o n . These specimens w i l l be creep t e s t e d and t h e r e s u l t s compared w i t h those for t h e i r r a d i a t e d samples. About 14 creep frames w i l l be w e d f o r t h e s e tests e

2.4.11.5

Subtask 1.1.7.5

C h a r a c t e r i z a t i o n of m i c r o s t r u c t u r e

"he development of a modified B a s t e l l o y N w i t h improved r e s i s t a n c e t o i r r a d i a t i o n i s based on developing a s p e c i f i c type of m i c r o s t r u c t u r e , and continued study of m i c r o s t r u c t u r e s i s a very important p a r t of t h i s program. Several a n a l y t i c a l t o o l s are used t o c h a r a c t e r i z e leicrostruct u r e s i n c l u d i n g transmisslon electronmicroscopy, e x t r a c t i o n r e p l i c a t i o n , x-ray and e l e c t r o n d i f f r a c t i o n , e l e c t r o n microprobe a n a l y s i s , and o p t i c a l metallography. Samples w i l l be s t u d i e d b e f o r e and a f t e r i r r a d i a t i o n and a f t e r long p e r i o d s of t h e m 1 exposure. The o b j e c t i v e w i l l be t o o b t a i n an in-depth c o r r e l a t i o n of d c r s s t r u c t u r e and mechanical behavior. V a r i a t i o n s from heat-to-heat w i l l be c o r r e l a t e d w i t h chemical a d process variables.

2.5

TASK @ROUP 1.2

PROC

OF COMMERCIAL HEATS

A f t e r a n a c c e p t a b l e composition f o r modified Wastelloy M has been d e t e r mined by t h e work i n Task Group 1.1, a t least f o u r l a r g e commercial h e a t s (%l0,000-lb) w i l l be procured for e v a l u a t i o n . 'fhe s p e c i f i c a t i o n s w r i t t e n f o r t h e procurement of t h i s material w i l l € o m t h e b a s i s f o r f u t u r e procurement. Orders € o r t h e f o u r h e a t s w i l l be placed w i t h a t least two vendors by competitive bidding. The material w i l l be obtained in product forms t y p i c a l l y used i n r e a c t o r c o n s t r u c t i o n . n e s e materials w i l l be c a r e f u l l y catalogued and utilized extensively in Task Group 1 . 3 ,

2-34

.2 5 1 a

Objective

The objective of t h i s task is to obtain f o u r large commercial heats a% the reference composition from two or more vendors f o r evaluation. 2 5* 2 0

Schedule

!J%e schedule far work on procurement of

commercial heats is shown in

Table 2.5.2.

2.5.3

Funding

Operating fund requirements f o r Task Group 1.2 are s k m in Table 2.5.3. C a p i t a l equfpment funds in t h e arnomt of $lO,OOO Wlll be required in ET 1977 far storage facilities to be w e d in Task 1.2.4, Receipt and Cataloging O f Ivkxterialts. 2-5.4

Task 1.2.1

Speeffications

The composition of the reference material w i l l . be fixed on the b a s i s of i n f o m a t i o n developed in Task Group 1,1. Specifications will be written that cover the allowable ramges for t h e important elenents. These specifications w i l l also cover melting practice and quality control prsced ~ r e sfor each product t h a t will be produced. 2.5.5

Task 1.2.2

Bidding and vendor selection

2.5.7

Task 1.2.4

Receipt and cataloging of material

2-35

Table 2.5.2.

Schedule f o r work i n Task Group 1.2 - Procurement of commercial heats

2.9 7%

1976

Specifications

1.2.1

P 2 2 Bidding and vendor s e l e c t i o n e

1.2.3

S u r v e i l l a n c e of f a b r i c a t i o n

1.2.4

Receipt and c a t a l o g i n g of material

j 1977 1978 El

1975

1 2 1 Specifications e

1976

I977 a0

1.2.2

Bidding and vendor s e l e c t i o n

1.2.3

S u r v e i l l a n c e of f a b r i c a t i o n

1.2.4

R e c e i p t and c a t a l o g i n g of material

Total o p e r a t i n g funds f o r Task Group 1 . 2

3 80 400

1978

2-3 6

"he four l a r g e heats will be evaluated with r e s p e c t t o several p r o p e r t i e s including m l d a b i l i t y , mechanical p r o p e r t i e s , compatibility with s a l t c o n t a i n h g f i s s i o n products, and physical p r o p e r t i e s . These t e s t s w i l l confirm t h e d e s i r a b i l i t y of the composition s e l e c t e d and w i l l provide s u f f i c i e n t d a t a f o r design of MSBW systems and components. T e s t s of at least 10,000 hr duration w i l l b e required for design purposes. The q u a l i t y of t e s t i n g will be m a i n t a b e d a t a high level t o provide information d t h t h e p r e c i s i o n necessary for design.

2.6.1

....

Objective

"be o b j e c t i v e of this task i s t o determine t h e mechanical and physical properties of t h e four reference h e a t s and to demonstrate t h a t t h e

p r o p e r t i e s observed in s m a l l h e a t s can be reproduced in commercial heats. P a r t f c u l a r emphasis w i l l be placed on evaluating the r e s i s t a n c e of the commercial h e a t s t o neutron embrfttlement and tellurium-induced fntergranular cracking.

2.6.2

Schedule

The schedule for work i n Task Group 1.3, Evaluation of Commercial Heats, is shown i n Table 2.6.2. 2 6 a

Fundin&

2.6.4

Facilities

The f a c i l i t i e s described i n Subsection 2.4.4 will be used f o r this t a s k group; howeverp additional mechanical property t e s t f a c i l i t i e s w i l l be required. These f a c i l i t i e s will be o b t a h e d through the purchase and construction of a d d i t i o n a l equ5pmgnrt and through subcontracts.

2.6 5

Task I.3 P Weldability

T e s t welds will be made i n many of the products Prm t h e four l a r g e heats. Stmetural welds are u s u a l l y made under conditions of high r e s t r a i n t , hence t e s t welds w i l l be made in which the two t e s t p l a t e s t o be j ~ i n e d together are each welded t o a steel p l a t e . This w i l l r e q u i r e t h a t the w e l d metal,defsm t o ace odate t h e d h e m s i o n a l changes r e s u l t i n g from

b...

2-37

Table 2.6.2.

Schedule for work in Task Group 1.3 - Evaluation of commercial heats Ffsea%

Weldability Mechanfeal property tests 1.3.2.1 Short-time tensile tests 1.3.2.2 Fatigue tests 1.3.2.3 Long-term creep 1.3.2.4 Special tests 1.3.2.5 Irradiation damage Physical 1.3.3.1 1.3.3.2 1.3.3.3

property measurements Thermal expansion Thermal conductivity Electrical conductivity

Thermal convection

corrosion

tests

Forced convection 1.3.5.1 EL-6 1.3.5.2 FCL-7 1.3.5.3 EL-8 1.3.5.4 PCL-9

corrosion

tests

In reactor

fuel

capsule

tests

year

2-38

Fiscal 1975

1.3.1 1.3.2

Weldability &ChaIIh2d PKopCYtqP t e s t s 1 . 3 . 2 .I Short-term tensile tests I o 3.2 * 2 Fatigue t e a t s 1.3.2.3 Long-term creep l. 3 2 - 4 Special t e s t s 1.3.2.5 I r r a d i a t i o n damage

Subtotal 1 3 * 2

1976

I977

1978

25 275

2P2

25 325 375 297

432

862

1022

15 10

5 18 10

10 150 125 147

358

1.3.4

T h e m 1 Convection s o r r s s i o n t e s t s

200

250

100

75 75 75 25

75 25

S u b t o t a l 1.3.5

l.P,6

In-reactor f u d c a p s d e t e s t s

T o t a l o p e ~ a t h gfunds for Task Group 2 . 3

200

250

350

425

1712

2047

- 457

. .

&.A,;

Sub total .l 3o 3

1979

....

,:.;.;.;I-

2-39

1975

I976

11 3 . 1

Weldab ility

1.3.2

Mechanical p r ~ p r t ytests 1-3.2.1 S h a r t - t i m t e n s i l e t e s t s F a t i g u e tests 1.3.2.2 1 . 3 . 2 . 3 Long-term creep 1.3.2.4 Special tests ~ r ~ a d i a t i saamge n 1.3.2.5

25 75 50 40

Sub t o t a l 1 . 3 . 2

20 0

1.3.3

Physical property meas urernents Therm1 expans ion 1.3.3.1 T h e m 1 conductivity 1.3.3.2 1.3.3.3 Electrical conductivity

75 75

3 58

11640

200

700

168

Therm1 convection tests

1.3.5

Forced convection ~ S S ~ S FCL-6 1.3.5.1

1.3.5.2

FQ-7

1.3.5.3 1.3.5.4

Pa-$

FCL-9

2 40

S u b t o t a l 1.3.5 In-reactor fuel capsules

Totab capital equipment funds

1979

5 5

1.3 - 4

1.3.6

1978

1.3.3

.... &&

1977

%CX

$0 I

80 25

Task Group 1.3

290

2-46

d i f f e r e n t i a l heating and c o o l i n g . The as-welded p l a t e s w i l l be exmined by dye p e n e t r a n t and x-ray techniques. Bead samples will be cut from the test welds for bending and e v a l u a t i o n by A m , Section VI11 guidel i n e s . Welding p ~ ~ c e d u w ~ iel sl be developed which o p t i m i z e the ease of Weldfng and the EEch2lniCal p%Op@KtieS O f the Wdd.

Weld smples wlll be subs ected t o suff i e i e n t mechanical property tests to develop b a s i c data f o r d e s i g n purposes. I n f o m a t i o n such as shorttern S ~ E S S - S ~ K ~ ~ I I b e h a v i o r , creep b e h a v i o r , stress-rupture data, and strain t o f a i l u r e will be determined. 2.6.6

Task 1.3.2

Mechanical property t e s t s

The mechanical p r o p e r t y t e a t s i n this t a s k w i l l p r o v i d e the d a t a r e q u i r e d f o r design purposes. The basic t y p e s of tests r e q u i r e d will be sliaort-te~-~~ t e n s i l e , creeps f a t i g u e , some s p e c i a l tests, and s m e tests of all types ofp i r r a d i a t e d smples. The test techniques must. be advanced somewhat over those used i n Task Group 2 . 1 i n o r d e r to o b t a i n t h e ~ e ~ p ~ i rdegree ed of p r e c i s i o n . Tests w i l l be run on several products frm a l l four h e a t s t o e s t a b l i s h scatter bands.

2.6.6.2

Subtask 1 . 3 . 2 . 2

Fatigue tests

2-41.

2.6.6.3

Subtask 1.3.2.3

Long-term creep

Creep tests of a t least 10,000-hr duration w i l l be required f o r t h e d e s i of a test r e a c t o r . These tests must be very p r e c i s e so that they accur a t e l y describe t h e strain-time behavior. The temperature range of conMany of t h e cern f o r time-dependent p r o p e r t i e s i s about 1608 t o 1400'P. tests w i l l be c a r r i e d out i n s a l t - f i s s i o n product environments, and o t h e r s w i l l be run i n a i r . Some samples w i l l be annealed p r i o r t o creep t e s t i n g t o determine the influence of annealing on t h e creep behavior. 2.6.6.4

...

..., ,.m

..&

...

.... ;pa

,*;A

.... , .>:,s ... ....

... ,*&

... 1 rll 9 '

Subtask 1.3.2.4

Special t e s t a

Several types of s p e c i a l i z e d tests w i l l be necessary t o c h a r a c t e r i z e t h e mechanical behavior of material from t h e f o u r l a r g e heats. One such type of t e s t i n g w i l l be combined creep and f a t i g u e tests t o develop a method of summing life f r a c t i o n s t o p r e d i c t f a i l u r e . Multiaxial stresses pose another problem. Analytical methods e x i s t f o r p r e d i c t i n g behavior under m u l t i a x i a l stresses on t h e basis of u n i a x i a l test data. Howeverlp some t e s t i n g must b e done t o c o n f i m t h a t these methods w i l l apply t o modif i e d Bastelloy N. 2.6,6.5

Subtask 1.3.2.5

I r r a d i a t i o n damage

Samples of the four h e a t s will be i r r a d i a t e d in the Om t o thermal f l u neutrons/cm2 and a t temperatures of 1880 t o enees of about 3 x The metal conditions w i l l include as-received, s o l u t i o n 1480'F. annealed, welded, and welded and s t r e s s - r e l i e v e d . Most of the samples w i l l be i r r a d i a t e d i n the unstressed condition and subjected t o posti r r a d i a t i o n creep t e s t i n g . These tests are necessary f o r determining the creep behavior and measuring t h e rupture t i m e and s t r a i n . About 8 ORR experiments w i l l b e completed, each containing about 188 samples. These samples w i l l be subjected t o p o s t i r r a d i a t i o n short-tern tensile afld creep tests. Some in-reactor tube b u r s t experiments w i l l be operated i n which tubular samples w i l l be s t r e s s e d and i r r a d i a t e d simultaneously. The t i m e t o f a i l u r e w i l l be measured during i r r a d i a t i o n and t h e creep s t r a i n deter&Red by p o s t i r r a d i a t i o n measurements. About 4 experiments of t h i s type w i l l be c a r r i e d out. 2.6.7

Task 1 . 3 . 3

Physical property measurements

The physical p r o p e r t i e s of nost importance i n design are t h e e l a s t i c constants, thermal expansion, thermal conductivity, and e l e c t r i c a l cond u c t i v i t y . These p r o p e r t i e s have been measured f o r standard Hastelloy M, but may be somewhat different for modified Hastellop N: Physical measurements w i l l be c a r r i e d o u t f o r t h e modified a l l o y i n order t o provide t h e d a t a required f o r design purposes.

2-4 2

2.6.7.1

Subtask 1.3.3.1

Thermal s p a n s i o n

2.6.3.2

Subtask 1.3.3.2

Thermal conductf-s~ity

Thermal conduetzvity is a necessary parmeter f o r design purposes. !l%is property xi11 be measured ow all four heats over the temperature range of 75 to 1808'F. Heasurmesats will be made on welds and base metal.

2,6,9

Task 1.3.5

Forced convection C ~ ~ K O S ~ Otests II

Themal convect3on l o o p s are a relatively hexpensive method sf determhing corrosion behavior. However, the salt flow v e l o c i t y in a thermal f e w feet E b U t e as CQIlnpared With V d o C i t i e S CoKVaCthn lSOp i% Only up to 20 ft per second in an MSBR. These higher v e h c i t f e s can increase the corrss io n rate markedly over that observed in thermal convection loops at the lower velosities. Thus, some corrosion testing must be done pmped syst s at realistic flow rates. A versatile forced eomvectiom

loop facility of near standard design has been developed for ~ ~ ~ ~ t e r i a l t e s t s of t h i s type. n e test facilities developed for loops FCL-2, -3, -4, and -5 will be m d 1 f i e d by refabricating a l l p a r t s that contact the s a l t from t h e new modffied materials. Work in forced eanveetion facilities associated with t h f s task (designated FCL-6, - T o discussed in "Ore detail in the following sections.

2-43

.....

2.6.9.1

Subtask 1.3.5.1

FCL-6

Tke p o r t i o n s of t h i s f a c i l i t y which c o n t a c t s a l t w i l l be f a b r i c a t e d from one of the comereial heats of modified Hastelloy %a. The facility w i l l be operated with fuel salt between the t e ~ ~ p e r a t u rlimits e sf 1050 and 1300°F. me f a c i l i t y will be equipped w i t h electrochemical probes f o r measuring the u”+/u4’ Katio, and wFfl have provisions for removable smples e

2.6‘9.2

Subtask 1.3.5.2

PCE-7

me PQHtiofkS of thdS facility Which Contact Salt Will be %&riCated

f ~ o ma d i f f e r e n t commercial h e a t of modified Hastelloy N from t h a t used in Subtask 1.3.5.1. ‘Phe f a c i l i t y w i l l b e operated w i t h fuel. s a l t over the temperature range of 1058 t o 1300°F. After operating for about 6 months to e s t a b l i s h a base-line corrosion rate9 t e l l u r i u m w i l l be added t o the s a l t , and subsequent. o p e ~ a t i ~ ws ti l l be concerned w i t h t h e behavior of t h i § element. me f a c i l i t y w i l l b e equipped w i t h electrochemical probes f o r measuring t h e U(III)/u(nv> k a t i o andl t h e tdlurigfmt %on con-= centration. The f a c i l i t y w i l l have provisisms f o r removable samples.

2.6.9.3

Subtask 1.3.5.3

FCL-8

The p ~ r t i ~ of n s t h i s f a c i l i t y which c o n t a c t s a l t w i l l be f a b r i c a t e d from the heat of modified Hastelloy M used t o c o ~ ~ ~ t the ~ u cfacility t f o r Subtask 1.3.5.1. The facility will be used t o c i r c u l a t e coolant s a l t over t h e temperatu-~erange of l000 to 130Q’F. E l e c t r o c h e d c a l probes will be instaababed to measure t h e o x i d a t i o n s t a t e and t h e concentrations of i m p u r i t i e s . The f a c i l i t y will have prseisfons for removable s a m p l e s . . . &,

.... .:.=

.... :.:y ., ...

.:&

2.6.9.4

Subtask 1.3.5.4

FCL-9

The portions of t h i s facPB2ty which c o n t a c t s a l t will be f a b r i c a t e d from t h e heat of modified Hastelloy M used t o eon~tructthe f a c i l i t y f o r Subtask 1.3.5.1. Tke f a c i l i t y w i l l be used t o c i r c u l a t e coolant s a l t ovex the temperature range of 1000 t o 1300°F. Electrsehexdca% probes will b e imstalPed ts measure the oxidation s t a t e and the c o n c e n t r a t i o n s of impurities. !l%e f a c i l f t y w i l l have p~ovisionsf o r remvable samples.

2.6.10

Task 1.3.6

In-reactor Pueled capsule tests

b - r e a ~ t ~f ur e l e d capsule t e s t s w i l l be to d a ~ n ~ t r a tthee cornpatib i l i t y of t h e four h e a t s sf modfffed Hastellsy N with fissioning f u e l salt. The capsules w i l l contain sna11 tubes ( ~ 1 / 2i n . d i m ) f i l l e d with well-characterized fuel salt. The t e a t s w i l l be operated for periods ranging from l 0 cycle (6 w e e k s ) to I year. The concentrations of fi§S%l@ Wterid. a d t h e irrad%a%$On gel?iOds w i l l be ChOSeR 80 to produce quantities of fission products equal t o those t h a t would be

2-44

produced p e r m i t area of m e t a l s u r f a c e i n a commercial MSBR. The p i n s w i l l b e e x m i n e d after i r r a d i a t i o n t o determine the e x t e n t of i n t e r g r a n u l a r crackimg i f any. P i e c e s of t h e t u b e s w i l l b e deformed a f t e r irrad i a t i o n t o determine whether c r a c k s form under t h e s e s e v e r e c o n d i t i o n s . About 6 experiments9 each c o n t a i n i n g 3 f u e l p i n s , w i l l b e c a r r i e d o u t .

The d a t a o b t a i n e d in Task Group 1.3 w i l l be analyzed and expressed i n analytical formats s u i t a b l e for use by d e s i g n e r s . Nodel. tests will b e c a r r i e d out as n e c e s s a r y t o develop high-temperature d e s i g n methods. The d a t a and t h e d e s i g n methods w i l l b e used for p r e p a r i n g a highte?Mpe%atUre P r e s s u r e Vessel &de Case for sUbmiSSiQII.

2.7 .l O b j e c t i v e

The O b j e c t i v e of t h i s task i s t o develop design methods f o r modified Hastelloy Ea.

2 e a. 2

Schedule

The s c h e d u l e f a r work in t h i s t a s k group i s shown in T a b l e 2.7.2. 2.7.3

Funding

Operating fund ~ e q u i r e f n e n t~~ S Kthis t a s k group are shown i n Table 2.7.3. C a p i t a l equipment funds w i l l b e r e q u i r e d i n the araumts of $50,000 and $$08,000 d u r i n g F"% 1977 and Fy 1978 r e s p e c t i v e l y f o r work r e l a t e d t o the development of a n a l y t i c a l d e s i g n methods.

2 7.4

Facilities

It i s q u i t e l i k e l y t h a t some model t e s t i n g w i l l b e n e c e s s a r y f o r t h i s l be t q s t r e s s e d and t h e defortask group. Models of e ~ m p l e xg e ~ ~ w~i l ~ mation compared w i t h t h a t p r e d i c t e d a n a l y t i c a l l y . This w i l l be c a r r i e d out in t h e mechanics laboratory i n Bldg. 9204-1. The o t h e r work w i l l be l a r g e l y a n a l y t i c a l i n nature a d w i l l make e x t e n s i v e use of the ucc-m computing f a c i l i t i e s . 2.7.5

Task 1.4.1

Data ana%ysis

Large m o u n t s sf mechanical p r o p e ~ t y d a t a will b e g e n e r a t e d i n Task Group 1.3. These d a t a w i l l b e analyzed i n d e t a i l and a n a l y t i c a l exlpressions developed f o r use by d e s i ers. Basic d a t a sets and m a l y t i e a P e x p r e s s i o n s

2-45

.... .... ..xb

... ....

Table 2 . 7 . 2 .

Schedule for work i n Task Group 1 . 4 -Development d e s i g n methods - ASME code case submissisna

of analytical

....

,&A,

,&...

1.4.2

Developent of d e s i g n methods

1.4.3

Submission of code case

Table 2 . 7 . 3 . O p e r a t i n g c o s t summary f o r Task Group 1.4 - Development of a n a l y t i c a l design methods - ASME code ease submission (costa in bOQ8 d o b l a r s )

1.4.1

Data a n a l y s i s

1.4.2

Development of design methods

1.4.3

Submission of code ease

Total operating funds for Task Group 1.4

108

215

717

168

LI.. Y

2-4 6

~ 5 lbe l developed for el> stress-strai~nbehavior as a f ~ n c t i o nof tmbehavfor as a function of parature and strain rate, (2) st~ess-rupt~re temperature, ( 3 ) strain-the behavior as a function of temperature and stress level, ( 4 ) fati ue response in the fsm of cycles to failure as a function of strain P ge at various temperatures, and (5) emulative d m g e relationships for adding fatigue m d creep damage. n e dl1 reflect the data spread due to heat-to-heat variations and mental uncertainties. Criteria will be developed f o r discarding ~ I X Q -

neous data. 2.7.6 Design methods W L l - 1 be developed for designing compl@x s y s t m s constructed of modified Hastellay M. These methods will likely be patterned after the existing high-temperature design code cases f o r type 384 and 316 stainless steel. me test results frm Task 6 . 3 . 2 will be used in developing design methods specifically for modified HastePloy N . Combined analytical and erhental methods w i n be used to develop design methods for comp1m stress histories. me initial aatalytical methods will be those crumently being developed f o r types %84 and 3 staiKll@sssteel. Hodel tests will then be run to confirm that the met d s developed f o r the austenitic steels can be used for Hastelfoy N h e such type of loadin ial stresses. 6afbaHytTcal methods ist for predicting creep nder m u l t l e a x i a l stresses on the ba ial t e s t data. Sealed r n ~ d e l sof actual reactor components will be subjected to multiaxial stresses and t h e resulting creep behavior I R ~ ~ S U K ~Hodel ~ . tests will also be carried out to assist in the development of methods for staenrning creep and fatigue dmage.

2.7.7

Task 1.4.3

Submission of code ease

After adequate data are o b t a h e d and design methods established, a code case will be submitted to the ASHE Boiler and Pressu~eVessel Gmmittee. This case ~ 5 1 1officfally e s t a b l i s h the design mles as being accepta b l e for use of modified HastelEoy N in nuclear service. A period of 6 months to 1 year will likely be required for approval after the case is submitted. During t h i s t h e it is quite likely that nmerous questioaPS % d f la K i S @ CoTKeTXIfHlg the SbabDlitted lE~te9f8.l. IRfo33W.tiOTl dll be provided and some further analytical development work may be required.

2-4 7

the molten-salt test r e a c t o r ( S e c t i o n 1 4 ) ; however, a d d i t i o n a l long term ~ ~ i t ~ ~d ai t a will l s b e r e q u i r e d f o r d e s i g n of subsequent r e a c t o r s .

2.8.1

Objective

The o b j e c t i v e of t h i s task is to obtain l o n g - t e r n c o m p a t i b i l f t y and mechanical p r o p e r t y d a t a on modified HasteHloy N.

2.8.2

Schedule

2e 8 . 3

Funding

2.8.4

Facilities

This t a s k w i l l make use of most of the f a c i l i t i e s d e s c r i b e d i n Subseetion 2.4.4. 2.8 5

:.... ..m

.... .....

,.%

... .... ......

'.X&

Task P I 5.1 . &chanical p r o p e r t y tests

Creep tests of lgb,OOO hr d u r a t i o n were run %n subtask 1 . 3 . 2 . 3 . Hmy of these tests Will be C O n t i I l U @ d f 8 P tillM2.S Up to 56B3(d80hKS (aYr). Tests of this d u r a t i o n are r e q u i r e d t o ensure that t h e material is s t r u c t u r a l l y stable f o r t i m e s w i t h i n a f a c t o r of 5 of t h e a n t i c i p a t e d o p e r a t f n g l i f e t h e of a reactor. Some of these t e a t s will be run in salt-tellurium environments s o t h a t t h e e f f e c t s of t h i s environment on t h e creep beh a v i o r can b e a s s e s s e d . It is likely t h a t 16 long-term creep t e s t s will b e run i n s a l t and 14 will be run in air.

postiPKadhtiOHn C%@ep t e S t s W i l l be eontiIlUed far t k W S Up EO 58,OW hr. These tests w i l l define the s t r a z n - t h e b e h a v i o r of the i r r a d i a t e d modified material a t low stresses comparable t o t h o s e used in r e a s t o r design. It is l i k e l y t h a t about 62 long-term pastirradiation creep t e s t s w i l l be run.

2.8.6 ..., ,wz,

Task 1.5.2

Forced circulation l o o p s

"be f o r c e d convection loopa descrTbed i n Task 1.3.5 w i l l c o n t i n u e oper-

ation f o r 50,080 hours.

Those loops were c o n s t r u c t e d of two heats of

Tata%

Operating

2.8.3.1.

fund

requixements (CQStx3 in

for Task Group %QQO da%%ars)

1.5

- Long

Fiscal %978

_..--..~~ 11.5.1 Mechanical gropePetytests

term

materia%s

tests

year

1979

1980

1981

1982

%983

1984

1985

650

500

580

450

308

1986

1.5.2

Forced circu%ation loops

150

100

1.5.3

In-reacms

200

operating

funds

P50 800

%.%.I mcl

100 700

PO0 700

100

Tstal

200 -%OOQ

Table

2.8.3.2.

Capital

term

matwA.a%s

tests

fueled

capsules fQK Task

Graup

equipment

1.5

fund

requirements (costs in 1080

%OQQ

for Task dollars)

Group

a.5

Long

Fisca% 1978 1.5.1

Mechanical

%.5.2

Forced

f.5.3

In-reactor

Total

capita%

property circulation fueled equipment

tests

funds

SOS Task

Gatoup 1.5

year

1979

1980

198%

1982

%983

1984

1985

lb0

25 60

5 35

25 55

5 30

5 40

5 30

loops capsu%es

580

5 40

1986

2-49

modified H a s t e l l o y N and two w i l l c i r c u l a t e f u e l s a l t and two w i l l C ~ K c u l a t e c o o l a n t s a l t . 'Phe first 10,880 hours of o p e r a t i o n w i l l p r o v i d e adequate i n f o m a t i o n f o r d e s i g n of a m o l t e n - s a l t test r e a c t o r ( S e c t i o n 141, b u t t h e a d d i t i o n a l 48,800 h r o p e r a t i o n w i l l b e very u s e f u l f o r f u t u r e r e a c t o r o p e r a t i o n . These f o u r loops w i l l have removable corr o s i o n samples, s a l t sampling and a d d i t i o n c a p a b i l i t i e s , a d probes f o r on-line chemical a n a l y s e s . Continued o p e r a t i o n of t h e s e l o o p s w i l l prov i d e v a l u a b l e i n f o r m a t i o n on c~rrosionb e h a v i o r . 2,8.7

Task 1.5.3

I n - r e a c t o r f u e l e d c a p s u l e tests

At l e a s t f o u r f u e l p i n s w i l l b e p l a c e d i n t h e QRR f o r l o n g - t e m o p e r a t i o n . These p i n s w i l l b e designed s i m i l a r t o t h o s e d e s c r i b e d i n Task 1.3.6. "he f u e l p i n s w i l l b e f a b r i c a t e d from t u b e s of the f o u r h e a t s of modified HastelBoy N. Fuel enrichment, i r r a d i a t i o n temperature, a ~ idr r a d i a t i o n t i m e w i l l b e t h e v a r i a b l e s . Operation of one c a p s u l e w i l l b e t e r m i n a t e d each y e a r so t h a t exposure t i m e s of 1, 2, 3 , and 4 y e a r s w i l l r e s u l t f o r t h e c a p s u l e s . The p i n s w i l l b e examined a f t e r i r r a d i a t i o n t o determine t h e e x t e n t of i n t e r g r a n u l a r c r a c k f n g , i f any. P i e c e s of t h e t u b e s w i l l b e deformed a f t e r i r r a d i a t i o n t o determine whether c r a c k s form under these conditions.

2.9

TASK GROUP 1 . 6

MATERIAL OPTIMIZATION

Although i t i s expected t h a t t h e a l l o y r e s u l t i n g from work i n Task Groups 1.1 through 1.5 w i l l b e adequate f o r c o n s t r u c t i o n of a m o l t e n - s a l t test r e a c t o r ( S e c t i o n 141, a demonstration r e a c t o r ( S e c t i o n 15) and comercia1 power r e a c t o r s , i t i s l i k e l y t h a t f u r t h e r a l l o y development w i l l l e a d t o materials which have improved c h a r a c t e r i s t i c s and m y a l l o w a r e l a x a t i o n of d e s i g n o r o p e r a t i n g c o n s t r a i n t s . A t t e n t i o n w i l l a l s o b e given t o t h e use of cheaper, IIIOK~ a v a i l a b l e materials f o r c o n s t r u c t i o n of power r e a c t o r s . 2.9.1

Objective

The o b j e c t i v e of t h i s t a s k i s t o develop S t p u C t u r d materials f o r t h e MSBR primary c i r c u i t t h a t are s u p e r i o r t o t h e d l o y developed i n Task Groups 1.1 through 1.5. It is i m p o r t a n t t h a t t h e s e improved materials b e pursued f o r f u t u r e a p p l i c a t i o n s .

2.9 2

Schedule

Work on a l l tasks i n t h i s t a s k group will b e c a r r i e d o u t c o n t i n u o u s l y d u r i n g t h e p e r i o d of FY 1979 through FY 1985.

2-50

2.9.3

Funding

Operating fund requirements f o r t h i s task group are a m r F a e d in Table 2 . 9 . 3 . 1 , and capital equipment fund requirements are shown in T a b l e 2.9.3.2. 2.9 4 a

Facilities

This task will make use of the same facilities as required for Task Group 1.3

2.9.5

Task 2 . 6 . 1

Further Hastelloy N improvement

It is likely t h a t the modified Hastellsy N developed in Task Groups 1.1 t k r ~ u g h1.5 will have a mximm service temperature between 1308 and 14Q0°P. 'phis upper limit is s e t by the temperature at which the earbide pPeciQitat@S CC?X'$Sefl and reskStt?nCe to n@Utron eElbK~tthIi~n$ decreases s h a r p l y . It would be desirable to develop a material which has a higher temperature limit SQ t h a t higher temperature transients could be accommodated. Improvement of modified Nastelloy %a can likely be effected by additional chemical modifications. 2.9.6

Task 1.6.2

Consideration of other materials

Other potential materials for t h e HSBR primary circuit offer several advantages over Mastellsy M, b u t have n o t been investigated sufficiently to d e f i n e t h e i r liXIlitation9. PQr e X a p % e , the i 3 U s t e n f t i C S t a h b e S S steels o f f e r the advantages of Imer e e e t , easier f a b r k a b i l i t y , and excellent resistance to i n t e r g r a n d a r cracking by tellurium, b u t it i s not clear what operating conditions (temperature ~ 3 + / ~ 4 r+a t i o ) must b e maintained in order to obtain an a c c e p t a b l e corrosion %ate. Enconel 600 and several s h i l a r a l l o y s contain 15 to 20% Cr. 'Pfe c h r s w i m o f f e r s improved resistance to embrittlexent by tellurium, b u t will also h c r e a s e t h e corrosion rate. me operating conditfons will b e defined for which the corrosion rate of these materials is acceptable. If the resulting operating cowditions warrant further study, additional development work w i l l be done

on these mterfals.

Table 2.9.3.1.

Summay of operating optimization

fund requirements far Task Group 1.6 - Material (costs in 1000 dollars) Fiscal 1979

198Q

I.981

1982

198%

1984

1985

N improvement

250

380

300

308

%QQ

sf other materials

180

10Q

148

188

208

220

%QQ

350

4QQ

448

48Q

580

520

1978 1.6.1

Further

1.6.2

Consideration

Total

aperating

Hastelloy

funds for Task Group I.6

Table 2.9.3.2.

year

Capital

equipment fund requirements for Task Group 1.6 - Material (costs in 1000 dallars) Fiscal

optimization

year

1979

1980

1981

1982

198%

1984

1985

N improvement

Ccxxdderation of other materials Total capital equipmfznt funds for Task Group 1.6

IQ -

28 -

30 -

%Q -

25 -

1978 1.6.1

Further

Hastelloy

1986

1.6.2

1986

2-52

REPEWNCES FOR SECTION 2

1. 6 . M. Adamson, R. s. carouse, and w. D. baanly, 1nter;m Report on C ~ P P O S ~b yO AZkaZi-MetaZ ~ F Z U ~ F & ~ S : Work to May I , 1953, o m - 2 3 3 7 (1959) '

3. W. 18. Manly et i t . , "Metaflurgical Problems in Molten Fluoride Systems," P r o p . N w Z . Enera S e r . I V 2: 164 (1960). 4.

H. E. McCoy, Jr., "The INOK-8

ORA% Bevim 3: 35 (1969).

6. H. E. McCoy, Jr., and R. E. Gehlbach, "Influence sf Irradiation Temperature on t h e Creep-Rupture Properties of H a s t e l l o y N," J . MueZ. TechzoZ. 11: 45 (19711.

8. J. H. DeVan,

Thesis University of Tennessee, KnsmiHle, 1960.

10. P. M. Haubenseich and 3. R. Engel, "Experience w i t h the MSRE," NucZ. AppZ. TechnoZ. 8: 118 (1970). 11. PI. W. Wosenthal, P. B. Kasten and R. B. Briggs, "Molten-Salt Reactors - History, S t a t u s and Potential," flucz. AppZ. TeekklaoZ. 8: 607 ( l 9 S S ) e

L....

2-53

15.

H. E. McCoy, Jr. A n EuaZution of t h e Molten-SaZt Reastop E;cpex?imen& HasteZloy N S m u e i l l m c e S p e c i m e n s - !l%ird Group, OB&-m-2647

(19709 16.

HI. E. McCoy, J r . , A n EVaZuation of t h e Molten-SaLt Reactor Experiment Hmtelloy N SmueilZance S p e c i m e n s - Pomth Gpoup, om-m-3063 (1971).

17.

B. E. M ~ G Q Y , J r . , The &§'RE and I t s Operatian, r e p o r t t o b e p u b l i s h e d .

18.

D. B. Harries, "Neutron I r r a d i a t i o n W r i t t l m e n t of A u s t e n i t i c S t a i n l e s s Steels and N i c k e l Base Alloys," J . B ~ t .NucZ. Energy Soe. 5: 74 (1966).

19.

G. H. Broomfield, D. R. Harries, and A. C. R o b e r t s , "Nelttron

H r r a d f a t i o n E f f e c t s i n A u s t e n f t i e S t a i n l e s s S t e e l s and a Nimonic Alloy," J . Iron Steel Inst. (London) 263: 582 (1965).

..&

.... . :.a

....

?;.;.i)

28.

N. A. Hughes and J . CaPey, "The E f f e c t of Neutron I r r a d i a t i o n a t E l e v a t e d Temperatures on t h e T e n s i l e P r o p e r t i e s of Some A u s t e n i t i c S t a i n l e s s Steels," J . Nucl. Mater. 10: 66 (1963).

21.

F. C. Robertshaw e t a l . , "Neutron I r r a d i a t i o n E f f e c t s i n A-286 H T M STP 341, American Sociekg H a s t e l l o y Y and Rene' 4 1 Alloys f o r Testing and MateriaZs, p . 372 (1963).

22.

N. E. Hinkle, " E f f e c t of Neutron Bombardment. on Stress-Rupture P r o p e r t i e s of Some S t r u c t u r a l A l l ~ y s , "ASTM STP 342, A m e m k a n Society for Testing and Materials, p. 344 (1964)

23.

P. C. L . P f e i l and B. R. Harries, " E f f e c t s of I r r a d i a t i o n i n A u s t e n i t i c S t e e l s and Other High-Temperature Alloys, " ASTM STP 380, American Socia% fop T'esting and Materials, p . 202 (1965).

24.

W. R. M a r t i n anel 3. R. Weir, J r . , "The E f f e c t of I r r a d i a t i o n Temperature on t h e P o s t - I r r a d i a t i o n S t r e s s - S t r a i n Behavior of S t a i n l e s s S t e e l , " MTM S P 380, M e m e a n Soeieky for Testing m d Materials, p a 251 (1965).

25.

J. T. Venard and 3. R. Weir, J r . , "In-Reactor Stress-Rupture P r o p e r t i e s of a 20 Cr-25 N i Columbium-Stabilized S t a i n l e s s S t e e l , ' ' ASTM STP 386, American S ~ e i e t yfor Testing m d MatefiaZs, p . 269 (19659.

26.

P. C. L. P f e i l , P. J. Barton, and D. R. A r k e l l , " E f f e c t s of I r r a d i a t i o n on t h e Elevated Temperature Mechanical. P r o p e r t i e s of A u s t e n i t i c S t e e l s , " Trans. of A m e k ? m W L E ~ . Sse. 8: 120 (1965).

2-54

30.

H. E. ~ e C s y ,JP., and 3. R. Weir, Jr., "Stress-Rupture P r o p e r t i e s of I r r a d i a t e d and Unirradiated Hasteabloy 09 Tubes flucZ. AggZ. 4 : 96 (1968).

36.

E. E. B1ooI11, fgNUeleat%onand Growth of Voids in Stainless S t e e l During pas t-Neutron Erradfation " Radiation-Indanced Voids in MataZs, ueSeU C Office of I n f o m a t i o n Services, p . 1 (1972) e

39.

H. E. McCoy, Jr. and R. E. Geiz%btrch, "Influence of Zirconium A d d i t i o ~ aon ~ t h e Hechanical P r o p e r t i e s of a Ni-No-Cr Alloy in the Irradiated and Unirradiated Conditions," J . M w Z . Mater. 4 0 ( 2 ) : 151-165 (1971).

2-55

43.

C . G. Bieber and R. F. Decker, "The Melting of Maleable Nickel and Nickel Alloys," T m m . AIM3 221: 629 (l96%>.

44.

D. Et, Wood and R. EI. Cook, "Effects sf Trace Contents 0% Pmpaarfty Elements ow t h e Creep-Rupture P r o p e r t i e s of Nickel-Base Alloys," f&-taZZuqia 109 (1963) a

,.... s:x ....

3. .>.;... *

3.1

INTRODUCTION

3.1.1

Objective

PUEk PROCESSING

.... ....

.... . :.x4

... .... ;H

The o b j e c t i v e of t h i s a c t i v i t y i s t h e development o f technology necessab-yf o r t h e d e s i g n of a p r o c e s s i n g system f o r a lQOO-MW(e) KSBR, and f o r e s t i m a t i n g t h e system performance, r e l i a b i l i t y , and c o s t s . 3.1.2

Scope

...

.C.&

...

.... ....

....xL

The scope of t h i s a c t i v i t y i n c l u d e s development and analysis of processi n g p l a n t flowsheets; s t u d y of t h e chemistry on which p r o c e s s o p e r a t i o n s are based; and d e s i g n and o p e r a t i o n of e n g i n e e r i n g experiments and faeili t i e s r e q u i r e d f o r developing t h e n e c e s s a r y f u e l p r o c e s s i n g technology. Task Group 2.1

3.1.2.1

Flowsheet a n a l y s i s

As promising f l o w s h e e t s are developed, e x i s t i n g computer codes w i l l b e

....

.... +a,

...... ,.:.=

used and new codes w i l l b e developed, when neces~alpgr, t o determine t h e f e a s i b i l i t y of t h e f l o w s h e e t s and to i d e n t i f y p r o p e r o p e r a t i n g c o n d i t i o n s . This t a s k group covers h e a t and mass b a l a n c e c a l c u l a t i o n s , p a r a m e t r i c and o p t i m i z a t i o n s t u d i e s , w a s t e c h a r a c t e r i z a t i o n , p r o c e s s i n g p l a n t c o s t estimates, p r o c e s s i n g p l a n t c o n t r o l s t u d i e s , and i d e n t i f i c a t i o n sf a l t e r n a t e processes. 3.1.2.2

Task Group 2.2

Continuous f l u o r i n a t o r development

%is t a s k group i s d i r e c t e d t o t h e development of technology r e q u i r e d f o r t h e removal of uranium from f u e l s a l t by f l u o r i n a t i o n . The work include^ development of h e a t s o u r c e s f o r n o n r a d i o a c t i v e tests, f l u o r b a t i o n chemi s t r y , f r o z e n w a l l c o r r o s i o n p r o t e c t i o n s t u d i e s , hydrodynamic m d mass t r a n s f e r s t u d i e s , and t h e d e s i g n and o p e r a t i o n of e x p e r i m e n t a l f a c i l i t i e s f o r e n g i n e e r i n g s t u d i e s s f f l u o r i n a t i o n . This task group i n t e r f a c e s w i t h Task Group 2 . 3 i n t h e F l u o r i n a t i o n - R e c o n s t i t u t i o n Engineering F a c i l i t y

t (

Task Group 2 . 3

3.1.2.3

.?A

Fuel r e c o n s t i t u t i o n

T h i s t a s k group i s d i r e c t e d t o t h e development of technology r e q u i r e d f o r recombination of uranium removed i n t h e f l u o r i n a t i o n s t e p w i t h t h e processed f u e l s a l t b e f o r e i t s r e t u r n t o t h e r e a c t o r ; t h i s i s accomplished by a b s o r b i n g t h e UFg i n t o s a l t c o n t a i n i n g UF4 t o produce s o l u b l e uP5s and s u b s e q u e n t l y reducing t h e UF5 t o UF4 w i t h hydrogen. '€%ist a s k group c o v e r s i n v e s t i g a t i o n s of t h e chemistry of t h e r e c o n s t i t u t i o n p r o c e s s , e n g i n e e r i n g s t u d i e s for p r o c e s s development, and t h e d e s i g n and o p e r a t i o n of a cornb i n e d f l u o r i n a t i s n - r e c o n s t i t u t i o n f a c i l i t y . This t a s k group i n t e r f a c e s w i t h Task Group 2.2 i n t h e PluoPinatisn-Bec0nstitugion Engineering Facility e

.:.... .=,

3-1 ,.,..... ..

( I

a- 2 3.1.2.4

Task Group 2.4

P r o t a c t i n i u m removal

~rotactiniua-233must be ~ s o ~ a t eandl d allowed t o decay to 2 3 % o u t s i d e t h e e cer e a s e in b r e e d i n g performance. r e a c t o r i n o r d e r to avoid an u ~ ~ d e s i ~ &d% me p r e s e n t flowsheet calls f o r e x t r a c t i n g 23%a f r o m the faisel salt ~ n t o molten bismuth c o n t a i n i n g d i s s o l v e d ~eductant. This task group includes development of salt-metah contractors for performing t h e e x t r a c t i o n , deV @ l O p E E n t Of COlltinWUs hydroflUorinat0PS and h y d % O C h l o r h a t o r s f o r saltbismuth systems, o p e r a t i o n of a csntinouous Reductive Ext~actionP r o c e s s ParsPlity f o r c a r r y i n g o u t e n g i n e e r i n g s t u d i e s of t h e p r o c e s s , and t h e d e s i g n , ~ o n s t r ~ c t and i ~ ~o p~e r, a t i o n of an experiment t o demonstrate i s o l a t i o n of p r o t a c t i n i u m u s i n g 23PPa. 2 3 5 s t a s k group i n t e r f a c e s w i t h Task Group 2,% i n t h e deveHogment of s a l t - b i s m u t h contaetsrs.

3.1.2.5

Task Group 2.5

Rare-earth removal

The p r e s e n t flowsheet c a l l s f o r removal of rare earths from t h e f u e l s a l t using t h e metab t r a n s f e r process. This t a s k group covers t h e development of salt-bismuth c o ~ t a ~ t o ~operation s, of Metal T r a n s f e r Experiment MTE-318, and d e s i g n , c o n s t r u c t i s n , a d operation of a f a c i l i t y f o r e n g i n e e r i n g s t u d i e s of t h e metal t r a n s f e r p r o c e s s u s i n flow rates which are about 10% Of those Kequ%%-edi n 1QQQ-NW(e) MBR

3.1.2.6

Task Group 2 . 6

Fuel s a l t p u r i f i c a t i o n

Before f u e l s a l t is r e t u r n e d to t h e r e a c t o r from t h e p r o c e s s i n g p l a n t t h e o x i d a t i o n potential of t h e fuel s a l t must b e adjusted t o a p r o p e r l e v e l and traces of bismuth and c o r r o s i o n products must b e removed. This t a s k group covers development of p r ~ c e s s e sf o r c o n t i n u o u s l y a d j u s t i n g t h e o x i d a t i o n potential by PlleSUIB Sf IIEaSUKfHag and cOntKOllhg t h e [ ~ 4 / ] ] r a t i o i n t h e f u e l salt, and the development of p r o c e s s e s for removing e n t r a i n e d and dissolved bismuth from t h e fuel salt.

[e3

3.l.2.7 I

Task G K Q U ~2.7 Actinide-fission product separatio~aand actinide recycle

The actinides c o n s t i t u t e a long-term waste h a z a r d and it is d e s i r a b l e to develop means for r e c y c l i n g them for t r a n s m u t a t i o n t o less u n d e s i r a b l e i s ~ t ~ p ei ns t h e r e a c t o r . This t a s k group covers the s t u d i e s of the necessalry caemistPgr for s e p a r a t i n g a c t i n i d e s f r o m f i s s i o n p r o d u c t s t o allow a c t i n i d e " r e c y c l e , t h e development and a n a l y s i s of flowsheets f o r implementing t h e s e types of p r o c e s s e s s and the identification of t h e required engineering d @ V @ l Q p B 3 l tZ t C b i V i t i e S . miS task gP0Up b t e K f a C @ S w i t h Task Group 2.1 i n t h e development and a n a l y s i s of flowsheets. I

-.-.

I..

3- 3

3.1.2.8

Task Group 2.8

MSBR Processing Engineeking Laboratory

T6tia task group covers t h e design (conceptual, T i t l e I, and Title 111, c o n s t r u c t i o n , aid acceptance t e s t i m g f o r a g e n e r a l l a b o r a t o r y facility i n w h i c h large engbneering development work can be carried out. %e f a c i l i t y will be used for a er Sf 62XIgk2eeK%HlgS t u d i e s refated to proeessing r n B R fuel.

3.1.2.9

Task Group 2.9

3.1.2. PO

Other activities

I n t e g r a t e d P r o c e s s Test Facility

*...A

3.2.1

S c h e d u l e and key program mflestolnes

A SLnltllan s c h e d u l e for the area of fuel gPocesSing is shown in Table 3,2.E.P, The key p ~ a g r nrflestones t~~~ f o r this activity are l i s t e d in Table 3.2.1.2 and occur at t h e times shown in Table 3.2.1.1.

$&... d

A summary of the operating budget for t h b activity is s h m i n Table 9.2.2-1, Table 3.2-2.2 shows req~~Lremnts for capital equip GPP funds in the mount of S355,QOO w i l l b e required d u r i n g FY I976 for m o d i f i c a t i o n of Cell 2, Bldg 3319, for the P r o t a c t i r a $ m %soPationDemonstration Experiment.

-.--

Fiesal Tack Group

2.1 2.2 2.3 2.4 2.5 2.6 2.7

2.8

2.9

year

3-5

Table 3.2.1.2.

Key m i l e s t o n e s f o r MSBR f u e l p r o c e s s i n g

M i l estone

Description

Demonstrate a u t o r e s i s t a n c e h e a t i n g f o r use i n a f r o z e n w a l f f l u o r i n a t or

Complete s t u d i e s of continuous f l u o r i n a t i o n i n engineering f a c i l i t y

Complete s t u d i e s of combined f P u s r i ~ e i o n - r e c o ~ ~ ~ t i o n i n e n g i n e e r i n g system on 25 t o 50% MSBR scale

Complete e n g i n e e r i n g s t u d i e s of f u e l r e c o n s t i t u t i o n n e c e s s a r y f o r d e s i g n of Fluorination-Recsnstitution Engineering Experiment

Complete e n g i n e e r i n g s t u d i e s o f r e d u c t i v e e x t r a c t i o n i n a mild s t e e l flow-through system

Complete e n g i n e e r i n g s t u d i e s of r e d u c t i v e e x t r a c t i o n i n Reductive E x t r a c t i o n P r o c e s s F a c i l i t y

Demonstrate i s o l a t i o n o f Pa by r e d u c t i v e e x t r a c t i o n u s i n g g r a m - q u a n t i t i e s of 2 3 1 ~ a

Complete experiment MTE-3B

1% BGBR scale

Demonstrate continuous a d j u s t m e n t of uranium v a l e n c e

I s s u e r e p o r t which d e s c r i b e s development actfvities necessary f o r t h e a c t i n i d e r e c y c l e flowsheet

Complete c o n s t r u c t i o n of MSBR P r o c e s s i n g Engineering Laboratpry

,.&.a

... ,< &

... .... ..... .=

.... ..... ,.... .. .,.u ...

.... ..... i!xQ

......,

. w

.... -fi%:

,-....r

Complete i n s t a l l a t i o n sf I n t e g r a t e d P K C X ~ ST~ e s t Facility

Complete o p e r a t i o n s and tests w i t h I n t e g r a t e d P r o c e s s Test Facility

I975

1976

1977

1978

1979

1980

250

295

150

190

165

190

240

350

I.600

1825

1795

595*

----P-w 931.

1981

1982

B983

1984

198%

275

591

2458 -v-P

2824

2700

445*

591*

2458

2824

2700

1986

Table 3.2.2.2.

Capital

Summary of capital

Continuous

2.3

Fuel reconstitution

2.4

Protactinium

2.5

Rare-earth

removal

2.6

Fuel salt

purificati.an

2.9

Integrated Process Test Facility: data pxxessing computer capital

.Capital 2.8 2.9

1975

1976

200

125

1977

1978

funds required

a979

for MSBR fuel

processing

1982

1983

1984

1985

200 ---200

ma)

4QO

3QO

3OQ

400

300

Fiscal

year

1980

3.981

Equipment and Facilitiee

2.2

Total

equipment and capital project (costs in 1000 dollars)

fluorinator

develapumt

removal

equipment

190

400

2630 25

funds

__ 715

400 425

400

Projects

MSBWProceesi~g Laboratory btegrated

Engineering

Process Test Facility

-K!,QOO 70QQ

1986

3-8

The rates a t which t h e f u e l s a l t must be processed f o r 233Pa removal and r a r e - e a r t h removal are mutually dependent. It w i l l b e convenient t o def i n e t h e tern f s p r ~ c e ~ s i n c ygc l e t i m e " as the t i m e r e q u i r e d for processing a volume of f u e l s a l t equal t o that contained i n t h e reactor system. The tV removal time" for a given material i s then an e f f e c t i v e cycle t i m e that is equal t o the p r o c e s s i n g eycle t i m e d i v i d e d by the f ~ a c t i o nof the material that is removed i n a pass t h r ~ u g ht h e p r o c e s s i n g system. For a p a r t i c u l a r s i n g l e - f l u i d HSBR having a b r e e d i n g r a t i o of 1.07, t h e re~ p f l - e dr a r e - e a r t h removal t i m e can range from 50 days for a protactinium removal t i m e of 3 days to about 11 days f o r a p r o t a e t i n i m removal t i m e of 20 days. The optimum c h o i c e of p r o t a c t i n i m and r a r e - e a r t h r e ~ ~ ~ a l t i m e s i s l a r g e l y dependent on t h e c h a r a c t e r i s t i c s of t h e processes employed. For example, t h e present rare-earth removal process r e q u i r e s t h a t protactinium b e removed from the s a l t prior t o t h e removal of rare earths. kgPc@9W i t h t h i s pPOCf2Ss9 t h e KaKe-eartk K e H l s V d tiate W i l l always be as long as o r longer t h a n the protactinium removal. t i m e . A p r f 3 t a C t h i W Ke€FIOPral time Of 18 days and a Kare-eaPth K e I I I O V d t h e s f about 27 days are used w i t h t h e r e f e r e n c e l p r o c e ~ s i ~system. ~g

3.3.2

Background

P r o c e s s i n g of MSBR fuel s a l t is based principally ow t h r e e types of o p e r a t i o n s : removal of uranium from the salt by f l u o r i n a t i o n ; t h e selective removal of p r o t a c t i n i u m , rare e a r t h s , and o t h e r f i s s i o n p r o d u c t s from the s a l t by extraction i n t o molten bismuth; and the recombination of uranium w i t h the processed s a l t by t h e hydrogen reduct i o n of TJF6 t o UF4 i n the p ~ e s e of ~ ~the e processed fuel carrier s a l t . In addition. t o t h e s e p r i n c i p a l o p e r a t i o n s there i s t h e n e c e s s i t y f o r a;taxiliary support systems and operations required f o r close-coupled f u e l processing 0

The chemical b a s i s on which the processing system fs f s m d e d i s w e l l u n d e r s t ~ o d ; however, only s m a l l e n g i n e e r i n g e ~ p e r h e n t shave been c a r r i e d o u t t o date and a c o n s i d e r a b l e e n g i n e e r i n g development e f f o r t remains. I

6... s..

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3-9

3.3.2.1 ... .$a

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Removal of uranium from molten s a l t s by f l u o r i n a t i o n

There i s a c o n s i d e r a b l e background and o p e r a t i n g e x p e r i e n c e r e l a t e d t o t h e removal of uranium from molten f l u o r i d e m i x t u r e s by c o n t a c t w i t h e l e m e n t a l f l u o r i n e . I n i t i a l work i n t h i s area w a s r e l a t e d t o t h e recovery of uranfum from t h e i r r a d i a t e d f u e l s a l t of t h e A i r c r a f t Reactor Experiment. The success of t h e development work l e d t o formation of t h e Fused S a l t F l u o r i d e V o l a t i l i t y Program a t OIw6, and o p e r a t i o n of a p i l o t plant: f o r b a t c h f l u o r i Operation of t h e p i l o t p l a n t w a s n a t i o n of the i r r a d i a t e d ARE f u e l salt.'2 h i g h l y s u c c e s s f u l , and upon completion of AWE fuel. p r o c e s s i n g , l a b o r a t o r y work w a s h i t i a t e d f o r t h e development of a f u e l element d i s s o l u t i o n opera t i o n based on c o n t a c t of f u e l elements w i t h hydrogen f l u o r i d e i n t h e p r e s e n c e of f u s e d f l u o r i d e mixtures i n o r d e r t o extend t h e V o l a t i l i t y Process t o o t h e r r e a c t o r f u e l s . 'This work culminated i n t h e h i g h l y succ e s s f u l recovery of uranium from v a r i o u s i r r a d i a t e d zirconium-, a1uminm-, and s t a i n l e s s s t e e l - b a s e d f u e l s , 2 3 which i n some cases were processed as e a r l y as 30 days a f t e r f u e l d i s c h a r g e . 2 4 Uranium r e ~ o v e r i e sg r e a t e r than 99% and uranium decontamination f a c t o r s i n excess of IO9 w e r e c o n s i s t e n t l y demonstrated e

Nore r e c e n t l y t h e Fused S a l t F l u o r i d e V o l a t i l i t y Process w a s used f o r removal of t h e 235U-238U m i x t u r e from t h e MSBE f u e l s a l t a t t h e MSIE s i t e a f t e r t h e r e a c t o r had o p e r a t e d f o r about 1.5 years.25 mis operat i o n w a s a l s o h i g h l y s u c c e s s f u l , and t h e f u e l carrier s a l t w a s s u b s e q u e n t l y combined w i t h and r e t u r n e d t o t h e MSRE f o r an a d d i t i o n a l y e a r of operation.

While t h e r e are a number ~f d i f f e r e n c e s between t h e e x p e r i e n c e gained w i t h t h e F l u o r i d e V o l a t i l i t y P r o c e s s and i n f o r m a t i o n r e q u i r e d f o r cont i n u o u s removal of uranium from MSBR f u e l s a l t , t h e V o l a t i l i t y P r o c e s s e x p e r i e n c e i n d i c a t e s c o n c l u s i v e l y t h a t uranium can b e removed from a v a r i e t y of f u s e d f l u o r i d e m i x t u r e s i n e s s e n t i a l l y a q u a n t i t a t i v e manner, and the broad e x p e r i e n c e on f i s s i o n p r o d u c t b e h a v i o r , materials of con~ s t r u c t i o n , and remote o p e r a t i o n is d i r e c t l y a p p l i c a b l e i n Y I I ~ Rimportamt cases. 3.3.2.2

Recombination of UFG w i t h processed f u e l carrier s a l t

There i s a vast e x p e r i e n c e i n t h e high-temperature gas phase r e d u c t i o n of UP6 t o UF4 by c o n t a c t w i t h hydrogen, and t h i s o p e r a t i o n has been s u c c e s s f u l l y c a r r i e d out i n a number of uranium p r o c e s s i n g f a c 5 b i t i e s . I n i t i a l l y , a t t e n t i o n w a s g i v e n t o u s e of a scaled-down r e d u c t i o n r e a c t o r of t h i s t y p e f o r recombining UFg w i t h processed MSBR f u e l carrier s a l t . However, c o n s i d e r a t i o n of the d i f f i c u l t i e s a s s o c i a t e d w i t h equipment scale-down, UF4 p r o d u c t c o l l e c t i o n and holdup, and remote o p e r a t i o n prompted a s e a r c h f o r a more d i r e c t means f o r recombining UFg w i t h molten f l u o r i d e m i x t u r e s . The known i n t e r a c t i o n s between UF6 and UF, in the absence of molten s a l t l e a d f n g t o t h e formation of s l i g h t l y v o l a t i l e f l u o r i d e s such as UF5s and - t h e o b s e r v a t i o n t h a t UP5 i s formed d u r i n g f l u o r i n a t i o n of molten f l u o r i d e s c o n t a i n i n g UF4, s u g g e s t e d t h a t

3-10

UP6 could be absorbed d i r e c t l y i n t o ~ ~ ~ o l st ae lnt t h a t contained UP+. Subsequent experiments v e r i f i e d that t h e a b s o r p t i o n r e a c t i o n i s r a p i d and t h a t W g can be combined q u a n t i t a t i v e l y with molten f l u o r i d e s cont a i n i n g BYFk with t h e simultaneous formation of i n t e r m e d i a t e flbusrides having a low v o l a t i l i t y . En the fuel r e c o n s t i t u t i o n s t e p , a gas strem containing UP6 and F’ will b e r e a c t e d w i t h a r e c i r c u l a t i n g s a l t stream essntainimg d i s s o l v e d UFL, according t o t h e r e a c t i o n s

The d i s s o l v e d UP5 will be reduced i n a separate chamber according to the reaction UP%(dl) + 1/2H;l(g) = UP,(d)

(3.3

4- HP(g>

~ r e ~ i m i n a rresults y I i n d i c a t e t h a t reaction ( 3 . 3 ) occurs more s l o w ~ p than r e a c t i o n ( 3 . 2 ) ; however, the f u l l s i g n i % i c a n c e of this i n t h e fuel r e c o n s t i t u t i o n step i s n o t known.

3.3.2.3

Distribution of metals betweem molten salts and bismuth

~ i s m u t his a low-melting (271°C) metal t h a t i s e s s e n t i a l l y i m i s c i b . l e W i t h HIQften halbide EIhCtUKeSi COnSi§ting Of flUOrideS, ClhlOrideS, and bromides. me vapor pressure of bismuth in the t e m p e r a t u r e range of i n t e r e s t (588 t o 700°C) i s negligible, a d t h e s o l u b i l i t i e s of lithium, thorium, u r a n i m , p r o t a e t i n i m , and m o s t of the fission produets are adequate f o r p r o c e s s i n g a p p l i c a t i o n s . Undeh- t h e conditions of i n t e r e s t , reductive extraction reactions between materials i n salt and metal phases can b e r e p r e s e n t e d by the I

rnJsalt)

* %Ei(Bi)

M ( B i > =I-IzLiXCsaPt)

in whish the metal h a l i d e i n the s a l t reacts with l i t h i m from the bisnutk phase to produce M in the bismuth phase a d t h e r e s p e c t i v e lithium h a l i d e i n the s a l t phase. The v a l e n c e of H i n t h e s a l t i s i%$ and %@p-PeSentS flUoriI2e9 CklQrhe, and bH01YIiPle. It has been found’ t h a t t h e distribtution c o e f f i c i e n t B f o r metal PI depends on the l i t h i u m concentration i n the metal phase (mole fraction, XLi> as follows :

3-11

The q u a n t i t y I# i s dependent o n l y on temperature, and t h e d i s t r i b u t i o n c o e f f i c i e n t i s m d e f i n e d by t h e relation:

D =

mole f r a c t i o n of M i n metal phase mole f r a c t i o n o f PIX i n s a l t phase %z

Tlhe ease w i t h which one component can b e s e p a r a t e d from a n o t h e r i s i n d i c a t e d by t h e r a t i o of t h e r e s p e c t i v e d i s t r i b u t i o n c o e f f i c i e n t s , t h a t i s , t h e s e p a r a t i o n f a c t o r . A s t h e s e p a r a t i o n f a c t o r approaches u n i t y , s e p a r a t i o n of t h e components becomes i n c r e a s i n g l y d i f f i c u l t . On t h e o t h e r hand, t h e g r e a t e r t h e d e v i a t i o n from u n i t y , t h e easier the separation. D i s t r i b u t i o n d a t a have been o b t a i n e d 2 f o r a Parge number of elements, h c l u d l h g a l l O f those Of i l l l p O r t ~ c e ,bemeen fuel s a l t (72-16-12 m01@ % LiF-BeF2-ThP4) and bismuth. Under t h e expected p r o c e s s c o n d i t i o n s , t h e Pa-rpln s e p a r a t i o n f a c t o r is about 1288, which i n d i c a t e s t h a t p r o t a c t i n i u m c t zirconium can b e e a s i l y e x t r a c t e d from a s a l t as w e l l as uranium a scream c o n t a i n i n g !lXF4 e However, the r a r e - e a r t h - t h o r i m separation f a c t o r s are c l o s e t o u n i t y (1.2 t o 3.5), i n d i c a t i n g t h a t d i r e c t selective e x t r a c t i o n of the rare e a r t h s from a s a l t c o n t a i n i n g t h o r i m fluoride would b e d i f f i c u l t . A p r e v i o u s r a r e - e a r t h removal method was based on t h e s e l o w s e p a r a t i o n f a c t o r s and r e q u i r e d a large number of s t a g e s , a h i g h m e t a l - t o - s a l t f l o w r a t i o , and a l a r g e electrolytic @ e l lf o r providi n g t h o r i m and r a r e - e a r t h reflux a t t h e ends of the e x t r a c t i o n cascade (ref. 3 , pp. 178-78; r e f . 4 , pp. 52-77). It w a s found s u b s e q u e n t l y t h a t w i t h LICE o r k i B ~ ,much more f a v o r a b l e t h o r i m - - r a r e - e a r t h s e p a r a t i o n factors are o b t a i n e d ( r e f . 21, p. 285). D i s t r i b u t i o n d a t a for L i C l (ref. 5 , p. 171;7) f a l l s roughly i n t o t h r e e groups. me d i v a l e n t rare-ea~th and a l k a l i n e - e a r t h elements d i s t r i b u t e m o s t r e a d i l y to t h e LiC1, w i t h t h o r i m - r a r e - e a r t h s e p a r a t i o n factors of me t r i v a l e n t rare e a r t h s have thorium--rare-earth separation about 1.08 factors of about PO4. Tetravalent materials, such as t h o r i m and protactinium, d i s t r i b u t e only s l i g h t l y t o L i C l . S t u d i e s on the temperature dependence of t h e d i s t r i b u t i o n d a t a show e s s e n t i a l l y no e f f e c t for t h e d i v a l e n t eEementss a minor e f f e c t f o r t h e t r i v a l e n t elements, and a somewhat g r e a t e r e f f e c t f o r t h e t e t r a v a l e n t elements. The d i s t r i b u t i o n coe f f i c i e n t f o r thorium i s deereased s h a r p l y by t h e a d d i t i o n of f l u o r i d e t o the L i C 1 , a l t h o u g h t h e dfstr2bution c o e f f i c i e n t s f o r the rare e a r t h s are a f f e c t e d by only a minor mount. Thus, contamination of t h e L i C l w i t h several mole p e r c e n t f l u o r i d e w i l l n o t a f f e c t t h e r e ~ ~ ~ of i tlh .e rare earths b u t w i l l c a u s e a sharp increase i n t h e thorium removal rate. Data w i t h E i B r G are similar t o t h o s e w i t h L i C l , and the d i s t r t b u t i o n behavfor w i t h L i C l - L i B r mfxtures would l i k e l y not d i f f e r a p p r e c i a b l y from t h e d a t a w i t h t h e p u r e materials. a

.:.PA

I I

3-12 3.3.2.4

Protactinium removal system

The refergnee protactinium removal system ( r e f . 7 , pp. 3-21) is based on f l u o r i n a t i o n f o r uranium removal and r e d u c t i v e e x t r a c t i o n for protactinium i s o l a t i o n . Fuel salt containing 0 . 3 3 mle X UF4 and approximately 0.0035 mole 2 PaFb i s withdrawn from t h e r e a c t o r . About 99% of the uranium is removed from t h e s a l t by f l u o r i n a t i o n i n o r d e r t o avoid t h e use of l a r g e quantities of r e d u c t a n t i n t h e subsequent protactinium removal s t e p . The s a l t stream i s f e d cskmtercursent t o a bismuth stream containing PithBum and thorium, where t h e remaining uranium and the protactinium t r a n s f e r t o the metal stream. n e s e materials are t r a n s f e r r e d from t h e bismuth t o a c a p t i v e secondary s a l t by h y d r o f l u o r i n a t i n g t h e bismuth stream l e a v i n g the e x t r a c t i o n c o l m i n t h e presence of the secondary s a l t . The S ~ C Q I - I ~ sEa~l ~t ~which flows through t h e hydrofluorinator SO cfrculates through a f l u o r i n a t o r , where about 90% of t h e w a n i m i s removed, and through a tank that contains most of the protactinium. LPthium is added t o t h e bismuth .heaving the h y d r o f l u o r i n a t o r , and t h e r e s u l t i n g stream i s returned to t h e top of t h e e x t r a c t i o n column. The s a l t leaving the e x t r a c t i o n cslumrr is e s s e n t i a l l y f r e e of uranium and protactinium but contains t h e rare e a r t h s a t e s s e n t i a l l y t h e r e a c t o r csncenbratisn. This stream is fed t o the r a r e - e a r t h removal system.

In the referenee r a r e - e a r t h ~e~lzsval system ( r e f . 8, pp. 1-15) f u e l s a l t , which i s f r e e of uranium and protactinium but c o n t a i n s t h e rare earths, i s countereurrentPy contacted w i t h bismuth containing r e d u c t a n t i n order t o e x t r a c t a s i g n i f i c a n t f r a c t i o n of t h e rare e a r t h s i n t s t h e bismuth. The bismuth stream, which eontalkHls t h e rare e a r t h s and thorium, i s then c o u ~ ~ t e ~ ~ u r r econtacted ntl.~ w i t h lithium c h l o r i d e . Because sf h i g h l y favorable d i s t r i b u t i o n c o e f f i c i e n t s , significant fractions of the e a r t h s transfer t o the EiCP along with a n e g l i g i b l e mount of t h o r i m . The f i n a l s t e p s of t h e process c o n s i s t i n e x t r a c t i n g t h e rare e a r t h s from t h e LfCP by c o n t a c t w i t h bismuth having l i t h i u m c o n c e n t r a t i o n s of 5 and 50 a t .

This process has a number of very d e s i r a b l e c h a r a e t e r i s t i i ~ . O f p r i m a r y b p o r t m c e i s the f a c t t h a t t h e r e is no n e t consmption of reduetant in the m o upper cowtactors. The process i s not s e n s i t i v e to &nor varia t i o n s i n o p e r a t i n g canditions. E s s e n t i a l l y materials o t h e r than t h e rare-eaKt%t and a l k d f n @ - e a P t h EdeBneRtS remoV@d froarm Or added to t h e f u e l s a l t ; t h e major change consists i n r e p l a c i n g t h e e x t r a c t e d rare e a r t h s with an e q u i v a l e n t m o u n t of l i t h i u m as LbF. The m o u n t of LBF added t o t h e f u e l salt in t h f s manner during 30 y e a r s of o p e r a t i o n would be less than 10% of the LIF inventory i n t h e r e a c t o r .

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3.3.2.6

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Conceptual p r o c e s s i n g p l a n t flowsheet

The r e f e r e n c e p r o c e s s i n g flowsheet ( r e f . 7, pp. 3-21) i s shown i n Pig. 3.1. Fuel s a l t i s withdrawn from t h e r e a c t o r on a 18-day c y c l e ; f o r a 1000-W(e) r e a c t o r , t h i s r e p r e s e n t s a flow rate of 8.88 gpm. The f l u o r i n a t o r removes 99% of t h e uranium. The p r o t a c t i n i u m e x t r a c t i o n cont a c t o r i s e q u i v a l e n t t o f i v e e q u i l i b r i u m s t a g e s . The bismuth flow r a t e through t h e c o n t a c t o r i s Q.13 gpm, and t h e i n l e t thorium c o n c e n t r a t i o n i n t h e stream i s 90% of t h e thorium s o l u b i l i t y a t t h e o p e r a t i n g temperat u r e of 640°C. The p r o t a c t i n i u m decay t a n k h a s a volume of 160 ft3. The uranium i n v e n t o r y i n t h e tank i s less than 0.2% of t h a t i n t h e r e a c t o r . F l u o r i d e s of l i t h i u m , thorium, zirconium, and n i c k e l accumulate i n t h e tank at a t o t a l r a t e of about 8.1 f t a / d a y . These materials are removed by p e r i o d i c withdrawal of s a l t t o a f i n a l p r o t a c t i n i u m decay and f l u o r i nation operation.

The bismuth flow rate through t h e two upper c o n t a c t o r s i n t h e r a r e - e a r t h removal system i s 12.5 gpm, and t h e L i C l flow rate i s 33 gpw. Each cont a c t o r i s equivalent t o three equilibrium stages. The t r i v a l e n t and d i v a l e n t rare e a r t h s are removed i n s e p a r a t e c o n t a c t o r s i n o r d e r t o minimize t h e amount of l i t h i u m r e q u i r e d . Only 2% of t h e LIC1, or 8.66 gpw, i s f e d t o t h e two-stage d i v a l e n t r a r e - e a r t h removal contactor, where i t is c o n t a c t e d w i t h a 0.58-ga1/day bismuth stream c o n t a i n i n g 50 a t . % l i t h i u m . The t r i v a l e n t s t r i p p e r , where t h e L i e 1 i s c o n t a c t e d w i t h b i s muth c o n t a i n i n g 5 a t . X l i t h i u m , i s e q u i v a l e n t t o one e q u i l i b r i u m s t a g e .

The bismuth stream c o n t a i n i n g t h e r e d u c t a n t n e c e s s a r y f o r t h e i s o l a t i o n of p r o t a c t i n i u m i s a c t u a l l y f e d to t h e r e c i r c u l a t i n g bismuth stream i n t h e r a r e - e a r t h removal system. An e q u i v a l e n t amount of bismuth i s withdrawn from t h e stream and is f e d t o t h e p r o t a c t i n i u m i s o l a t i o n column. This allows f o r more n e a r l y complete e x t r a c t i o n of t h e p r o t a c t i n i u m and prov i d e s a means f o r removing materials which might otherwise accumulate i n the recirculating stream.

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.::..&.

...X.... . &

The r e m i n i n g s t e p s i n t h e flowsheet c o n s i s t i n combining t h e processed s a l t w i t h uranium and p u r i f y i n g t h e r e s u l t i n g f u e l s a l t . The uranium a d d i t i o n i s accomplished by a b s o r b i n g t h e UFG-F~stream from t h e f l u o r i n a t o r s i n t o f u e l s a l t c o n t a i n i n g UFb, which r e s u l t s i n t h e formation of s o l u b l e UF5. The UFg i s t h e n reduced t o UFt, by c o n t a c t w i t h hydrogen. The HF r e s u l t i n g from r e d u c t i o n of UFg i s e l e c t r o l y z e d i n o r d e r to r e c y c l e t h e c o n t a i n e d f l u o r i n e and hydrogen. These materials are r e c y c l e d i n o r d e r t o avoid waste d i s p o s a l charges on t h e material t h a t would be produced i f t h e HF were absorbed i n an aqueous s o l u t i o n of KOBe9 The s a l t w i l l b e c o n t a c t e d w i t h n i c k e l wool i n t h e purification s t e p i n o r d e r t o e n s u r e t h a t t h e f i n a l bismuth c o n c e n t r a t i o n i s a c c e p t a b l y low.

The p r o t a c t i n i u m removal t i m e o b t a i n e d w i t h t h e flowsheet is IO days, and t h e r a r e - e a r t h removal times range from 17 t o 51 days, w i t h t h e rare e a r t h s of most importance b e i n g removed on 27- t o 38-day c y c l e s . C a l c u l a t i o n s ( r e f - 7 , pp. 3-21; r e f . 8, pp. 1-15) i n d i c a t e t h a t t h e flowsheet is relat i v e l y i n s e n s i t i v e t o minor v a r i a t i o n s i n o p e r a t i n g c o n d i t i o n s , such as

e J=-

5 +

L! L*

3-14

.--A

I I

I I I

I I

I I I I I

I I I

I I

t f

I I I I

c L

i i

I I I

I I

I I I I

.-I

3-15 changes i n temperature, flow rates, r e d u c t a n t c o n c e n t r a t i o n s , e t c . It .was noted e a r l i e r , however, t h a t t h e t h o r i a - - r a r e - e a r t h s e p a r a t i o n f a c t o r decreases sharply as t h e c o n c e n t r a t i o n of f l u o r i d e i n t h e LiCl i s h c r e a s e d ; contamination of t h e LiCP would r e s u l t from entrainment of f u e l s a l t by t h e bismuth stream l e a v i n g t h e upper contactor. The e f f e c t i s l a r g e l y an i n c r e a s e i n t h e rate a t which thorium i s removed with t h e rare e a r t h s . The t h o r i m removal rate i n c r e a s e s from about Q.4 mole/day with no f l u o r i d e i n the LiC6 t o about 288 moles/day when the L i e 1 contains t h e equfvalewt of 5 mole Z LIF. It appears t h a t the f l u o r i d e concentration i n t h e LfCl could esonowiealfy be as high as 2 mole X , which corresponds t o a thorium d i s c a r d r a t e of 7.7 molesfday. to Discard of thorium a t t h i s r a t e would add only about 0.0013 ~~ill/lcWlar the power c o s t ; however9 t h e presence of thorium i n t h e r e s u l t a n t waste complicates waste d i s p o s a l considerations. me effect of f l u o r i d e f n the LiCb ow t h e K ~ U I O Vof~ ~rare e a r t h s is n e g l i g i b l e . In f a c t , the r a r e - e a r t h removal e f f i c i e n c y i n c r e a s e s s l i g h t l y as t h e f f u ~ ~ i . dconcene t r a t i o n i n t h e LiCl i n c r e a s e s . In a d d i t i o n , c o n t a c t of LfCI containing f l u o r i d e with volati1e BiCl3 r e s u l t s i n formation of v o l a t i l e BP3 ( r e f . BO, p . 1061, amd thus f l u o r i d e can be removed from Li61 e a s i l y by t h i s means. The r e l i a b l e removal of decay h e a t from the processing p l a n t i s an 2mpsrt a n t c o n s i d e r a t i o n because of t h e r e l a t i v e l y s h o r t decay t i m e before t h e s a l t enters t h e processing p l a n t . A t o t a l of about 6 !%I sf heat would be produced in t h e p r o c e s s h g p l a n t f o r a 10648-NW(e) NSBR. Since molten bismuth, fuel salt, and EiCP are not s u b j e c t t o r a d i o l y t i c degradation, t h e r e i s not t h e usual concern encountered with processing of short-decayed f u e l .

3.3.3

3.3.3.1

S t a t u s of development Continuous f l u o r i n a t o r development

S t u d i e s have been c a r r i e d out previously'l on f l u o r i n a t i o n of molten s a l t a l-%n.-dl&UIl, 72-dKI.-BCW.g n i e k d f l U O r h a t O K that d h W e d @CJLUlterCUTXen$ c o n t a c t of molten s a l t wbth f l u o r h e . In t h e s e tests, molten s a l t (41-24-35 mole X NaF-LiF-ZrFq) containing UF4 w a s c o u n t e r c u r r e n t l y contacted w i t h a O ~ q u a n t i t y of f l u o r i n e i n excess of t h a t r e q u i r e d f e r the C Q ~ V ~ K Sof~ BF4 t o W 6 . Experiments were c a r r i e d o u t w i t h temperatures ranging from 525 t o 6OO0C, UF4 concentrations i n t h e feed s a l t ranging from 0.12 t o 0.35 mole X , and a range of s a l t and f l u o r i n e feed rates. The f r a c t i o n of t h e uranium remved from t h e s a l t ranged from 97.5% t o 99.9%. i l l

Axial d i s p e r s i o n in t h e s a l t phase w i l l be important i n t h e design of contfnwue; fluorfnators, and gas holdup and a x i a l dispersion have been measured i n coluxnas having diameters ranging from 1 t o 6 in. using a i r and aqueous solutions. Data w e r e obtained f o r wide. ranges of v i s c o s i t y , s u r f a c e tension, md s u p e r f i c i a l gas v e l o c f t y . C o r r e l a t i o n s f o r gas holdup axial d i s p e r s i o n were developed12 WMSA are b e l i e v e d t o b e a p p l i c a b l e to countercurrent contact of mlten s a l t a d fluorine i n a continuous f l u o r i n a t o r . These c o r r e l a t i o n s iawd t h e d a t a ow uranium

3-16 removal i n the l-in.-diam continuous f l u o r i n a t o r w e r e used for estimating the p e r f o m a x e of l a r g e r diameter cont2nuous f l u o r h a t o r s ( r e f . 1 2 , p. 41). The combination of molten salt and f l u o r i n e r e s u l t s i n a highly corrosive ~our isn a t o r ~ ~ V ~ P Q X X ~ E and I B ~ ,i t w i l l be necessary t o p r o t e c t a c o n t i ~ ~ f~l u from corroslon by maintainimg a l a y e r sf frozen salt OR s u r f a c e s t h a t would otherwise contact b o t h molten salt and f l u o r i n e . U s e of a frozen s a l t l a y e r f o r preventing t h e d i s s o l u t i o n of n i c k e l f l u o r i d e from a n i c k e l surface will d l w p a s s i v a t i o n of t h e n i c k e l t o occur. The f e a s i b i l i t y of m a h t a i n i n g frozen salt l a y e r s i n gas-salt c o n t a c t ~ r s w a s demonstrated previously8 fn tests i n a 5-im.-diam, 8-ft-high simul a t e d f l u o r i n a t o r i n which molten s a l t (66-34 mle % LiIF-ZrFb) and argon An internal h e a t source in t h e m a t e n were c o u n t e r c u ~ ~ m t lcontacted. y region w a s provided by Calrod heaters contained i n a 3/4-in.-diam p i p e d o n g t h e c e n t e r l i n e o f t h e v e s s e l . A frozen s a l t l a y e r w a s maintained i n the s s t e m with equivalent volumetric h e a t generation rates of 10 t o 55 Kw/%t e For comparison, t h e h e a t generation rates i n f u e l s a l t imeedi a t e l y after removal from t h e r e a c t o r and a f t e r passing through v e s s e l s having holdup times of 5 and 30 Illin are 57, 27, and E2 kW/ft3, respectively.

Ope~ationof a continuous fluorinator with nsnradiaaetive s a l t r e q u i r e s a means for generating h e a t i n the molten 5alt t h a t is n o t s u b j e c t t o ~ o r r o s i o n . Radio-frequency fnduction h e a t i n g w a s studied i n f l u o r i n a t o r simu~ationsw i n g n i t r i c acid1 3 and auto-resistance heating using ~ O - H Z power with molten s a l t (65-35 mle X LIF-BeF2) wa5 s t u d i e d i n a 6-%n.-dim f ~ ~ o r i n simulator a t ~ ~ 14 d to resistance heating is the p r e f e r r e d m e t ~ ~ o d S h c e it Can be W e d Over a WfdeH r a g e of operating C33IldkthTlS and Since t h e e l e c t r i c a l p w e r supply is much simpler than t h a t required %OK induct i o n heating.

Studies ~f the abs~plat%on of by MSBR f u e l carrier s a l t conta2ntng UF4 have been c a r r i e d o u t . l4 Absorption of UF6 in f u e l carrier s a l t containing UFq has been shown to result i n the formation of s o l u b l e aontaolatilaccording t o the following r e a c t i o n :

Since both U F g and UFg a r e s t r o n g oxidants, t h e t n f t i a l experiments were conducted p r l m r i l y t o ffnd a matertal t h a t was inert t o these species. I

....

3-17 .... ..... . : . : . y , -

~.= ...... i i i

:.....

.... ,fz&

~ e was : found t h a t a t 60Q°C, n i c k e l , copper, a d g r a p h i t e are not s u f f i c i e n t l y i n e r t but t h a t gold i s s t a b l e Both t o gaseous UP6 and t o salt containing up t o 6 w t % UF,. Consequently, c u r r e n t s t u d i e s are being conducted i n gold apparatus. Future experiments w i l l be c a r r i e d out with UFg-F, mixtures i n order t o determine t h e e f f e c t of the presence of f l u o r i n e i n t h e gas stream. The behavior of t h e f l u o r i d e s of iodine and neptunium i n t h i s s t e p w i l l d s s be determined. Results from s e v e r a l experiments show t h a t UFg undergoes gas phase disproportionation t o UP6 and UF4. The s t u d i e s also i n d i c a t e t h a t t h e s o l u b i l i t y of TJF6 i n t h e s a l t i s low. Engineering experiments are being designed f o r f u r t h e r study of t h e absorption of UFG-F~mixtures in molten s a l t containing bTF4 and t h e subsequent reduetion of UF, by contact of t h e salt with hydrogen.

3.3.3.3

.... .. ;.;.y -4

,.m

..... w

Protactinium removal

A salt-bismuth reductive e x t r a c t i o n f a c i l i t y has been operated successf u l l y i n which uranium and zirconium w e r e e x t r a c t e d from salt by csuwtercurrent contact with bismuth containing reductant (ref. 7 , pp. 6 4 - 8 9 ; r e f . 14)- Mare tham 95% of t h e uranium was e x t r a c t e d from t h e s a l t by a 8.82-in.-diarn, 24-ine-long packed column. The i n l e t uranium concent r a t i o n i n the s a l t was about 25% of t h e uranium concentration i n the reference MSBR. These experiments represent t h e f i r s t demonstration of

w d u c t i v e e x t r a c t i o n of uranium i n a flowing system. I n f a m a t i o n on t h e rate of mass t r a n s f e r of uranium and zirconium has a l s o been obtained i n t h e system using an i s o t o p i c d i l u t i o n method, and ETU values of about 4.5 f t w e r e obtained. Correlations have been developed ( r e f . 15, pp. 162-17; r e f . 12) f o r flooding and dispersed-phase holdup i n packed columna during countercurrent flow of l i q u i d s having high d e n s i t i e s and a l a r g e d i f f e r e n c e i n d e n s i t y , such as s a l t and bismuth. These c o r r e l a t i o n s , which have been v e r i f i e d by studies w i t h molten s a l t and bismuth ( r e f . 7, pp. 64-89], w e r e developed by study of countercurrent flow of mercury and w a t e r o r high-density organics and water i n 1- and 2-in.-diam columns packed with s o l i d cylinders and Raschig r i n g s varying i n s i z e from 1 / 8 t o 1 / 2 i n . Data on a x i a l d i s persion i n t h e continuous phase during t h e countercurrent flow of highdensity l i q u i d s i n packed columns has a l s o been obtained ( r e f . 16, pp. 58-89; r e f . 171, and a simple r e l a t i o n for p r e d i c t i n g t h e e f f e c t s of axial d i s p e r s i o n on colurmn performance'* has been developed. The successful operation of salt-metal e x t r a c t i o n c s l m s is dependent upon t h e a v a i l a b i l i t y of a bismuth-salt i n t e r f a c e d e t e c t o r . The successf u l operation of an eddy-current-type i n t e r f a c e d e t e c t o r t h a t c o n s i s t s of a c e r d c form on which b i f i l a r primary and secondary c o i l s w e r e wound w a s demonstrated r e c e n t l y . l4 Contact of t h e c o i l s with molten s a l t o r bismuth is prevented by enclosing t h e element i n a molybdenum tube. Passage of a high-frequency a l t e r n a t i n g current through t h e primary coil induces a c u r r e n t i n t h e secondary c o i l whose magnitude is dependent on the c o n d u c t i v i t i e s of t h e adjacent materials; s i n c e t h e conduct i v i t i e s of bismuth and salt are q u i t e d i f f e r e n t , t h e induced c u r r e n t

3-18

reflects the presence or absence of bismuth. The detector appears to b e a practical and sensitive indicator of either salt-bismuth interface location or bismuth level. ensive to build and because of Because colm-type contact t h e faref s a l t and introducing the likelihood of entrainin it into the reactor, a mechanically agitated contaetor f n which the phases are relatively m i l d l y agitated and are not dispersed is being considered. H o s t of the e x p e r h e n t a l work reported in the literature far t h i s type contactor has been done with partially miscible solventwater systems that produce Reynolds numbers almost an order of magnitude lower than those expected in sdt-bismuth systems. The variables of greatest significance in c o ~ ~ e l a t i nmass g transfer rates in this t y p e contact^^ are beliepied to be the surface tension and the kistematic visc o s i t y ( v l p ) . mese properties of the mercury-water system are close to the s m e propertie% of m l t e n salt-bismuth s y s t e ~ ~and , ~X~~X%XEIK%S W ~ P E ! carried o u t f o r detemining mass transfer coefficients with the rcul~)~-water system in order to verify the applicability of reported mass transfer correlations to salt-bismuth system. me mass transfer perfomance of this type of contactor is s t r o n g l y dependent on cell geometrys and t e s t s wera carrfed o u t using rectangular contactsrs havtng elposs sectional areas as large as 1 ft'. Agitators having a range of diameters and paddle characteristics were used. Ira t h e tests, the r a t e of transfer of l e a d fKoIll dilute pb(No3)2 SolUtions h t Q a ZhC-XIl@~CEI?Tj' amalgam was measured anel the mass transfer rates were compared with literature correlations. Although all literature correlations . ~ p e p ~ t ~ h c e d the aqueous-organic data f a i r l y w e l l , they did not correlate the mass transfer data from the water-mercury system. A csrreEatPon was developed which c o ~ r e l a t ethe ~ aqueous-organic data of o t h e r s as well as the watermercury data. A $-in.-diam contactor was installed in t h e f l m - t h r o u g h reductive extraction facility in place of the packed column contactor previously w e d in order to obtain additional mass transfer coefgicient data. The mass transfer rates observed in the salt-bismuth system are h i g h e r than those p r e d i c t e d by t h e Pecentlgr developed @OKpelatiOn.

Design and devePo ment work has been initiated on a Reductive Extraction Process F a e i l i t y l f that w i l l allow operation of the important s t e p s for the ~eductfveextraction process for protactinfum isolation. "Phe facility will d h w countercurrent contact of s a l t and bismuth s t r e types of cmtactsrs at € l o w rates as high as about 25% of those required for processing a 1000-rn(e) MSBR. me facility will operate continuously a d WEPP allow measurement of Inass transfer and hydrodyn&e data under steady-state conditions.

3.3.3.4

Rare-earth removal

w i t h thorium, and EICP. me f l u o r i d e s a l t i n i t i a l l y c o n t a i n e d '477~~1~3 a t the tracer l e v e l and LaF3 a t a c o n c e n t r a t i o n of 0.04 mole f r a c t i o n . During t h e experiment, t h e rare e a r t h s were s e l e c t i v e l y e x t r a c t e d i n t o t h e LiC1 d o n g wBth a n e g l i g i b l e amount of thorium. P r o v i s i o n was made f o r c i r c u l a t i n g the L i C l through a chanber c o n t a i n i n g bismuth having a l i t h i u m c o n c e n t r a t i o n of 38 a t . %, where t h e rare e a r t h s and thorium w e r e removed. The d i s t r i b u t i o n rarios for t h e rare e a r t h s ~ e ~ ~ ~ a i n e d c o n s t a n t d u r i n g t h e experiment at abaut the expected values. About 58% of t h e neodymium and about 70% of t h e lanthanum w e r e colbPected i n the L i - B i s o l u t i o n . The f i n a l t h o r i m c o n c e n t r a t i o n i n t h e ] t i - B i s o l u t i o n was b e l m 5 ppm, making the r a t i o of rare e a r t h s t u thorium i n the Li-Bi g r e a t e r than I O 5 t i m e s t h e i n i t i a l c o n c e n t r a t i o n r a t i o i n the f u e l s a l t and t h u s demonstrating t h e selective removal of rare e a r t h s from a f l u o r i d e s a l t c o n t a i n i n g thorium. A l a r g e r metal t r a n s f e r experiment ( r e f . 19, pp. 254-55; r e f . 28, pp. 209-12; r e f . 1 4 ) h a s been o p e r a t e d t h a t used s a l t a d bismuth flow rates t h a t w e r e about I% of the v a l u e s r e q u i r e d for p r o c e s s i n g a l 0 Q O - ~ ( e ) MSBR, and the p r e l i m i n a r y d e s i g n h a s been c a r r i e d out f o r an experiment t h a t w i l l use a . t h r e e - s t a g e salt-metal c o n t a c t o r and f l o w rates t h a t are 5 t o IQX of those r e q u i r e d for a IOOO-MW(~) M S B R . ~ ~

...&

3.3.3.5

Bismuth removal and uranium v a l e n c e adjustment

I n a p r o c e s s i n g p l a n t , t h e f u e l s a l t w i l l be c o n t a c t e d w i t h bismuth cowt a i n i n g r e d u c t a n t i n o r d e r t o remove p r o t a c t i n i u m and the rare e a r t h s . It will b e n e c e s s a r y t h a t e n t r a i n e d o r d i s s o l v e d bismuth b e removed from t h e s a l t b e f o r e it i s r e t u r n e d t o t h e r e a c t o r , s i n c e n i c k e l is q u i t e s o l u b l e in bismuth (about IO wt W > a t t h e r e a c t o r o p e r a t i n g temperature. E f f o r t s t o measure t h e s o l u b i l i t y of bismuth i n salt have 5 n d i s a t e d t h a t t h e s o l u b i l i t y i s lower than about l ppm, and t h e expected s o h b i P i t y of bismuth i n t h e salt is very l o w under the h i g h l y reducing c ~ ~ ~ d i t i othat n s w i l l b e used. For t h e s e reasons, i t is b e l i e v e d t h a t bismuth can only be present at s i g n i f i c a n t concentrations in the s a l t as e n t r a i n e d metallic bfsmuth. ....

$&,

.... : *H

.;.... ..... .X&

... .... . a

In o r d e r t o ckaraeterfze t h e bismuth c o n c e n t r a t i o n l i k e l y t o b e p r e s e n t i n t h e s a l t a f t e r it i s c o n t a c t e d w i t h bismuth, we have done p e r i o d i c sampling of s a l t i n e n g i n e e r i n g experiments i n v o l v i n g c o n t a c t of s a l t and bismuth. The r e s u l t s i n d i c a t e d t h a t t h e bismuth c o n c e n t r a t i o n i n t h e s a l t in moat cases ranges from 1 0 t o 100 ppm a f t e r c o u n t e r c u r r e n t c o n t a c t of the salt and bismuth i n a p a c k e d - e s l m c o n t a c t o r ; however, e o n c e n t s a t i o n s belaw 1 ppm are observed i n s a l t l e a v i n g a stirredi n t e r f a c e salt-metal e o n t a c t o r i n which the s a l t and m e t a l phases are n o t d i s p e r s e d . One 0 % t h e p r e s e n t d i f f i c u l t i e s i s p r e v e n t i n g contam%n a t i o n of t h e samples w i t h small q u a n t i t i e s of bismuth d u r i n g c l e a n i n g of t h e samples and t h e ensuing skenaieal a n a l y s e s . A n a t u r a l c i r c u l a t i o n loop c o n s t r u c t e d of H a s t e l l o y N and f i l l e d w i t h fuel salt has been o p e r a t e d f o r about two years; a EnsHybdenm cup cont a i n i n g bismuth was p l a c e d near t h e bottom of the loop. To d a t e , t h e

3-20 reported concentrations of bismuth in salt f r ~ wthe loop (4ppm) are essentially t h e same as those reported f o r salt from a loop containing no bismuth. N o degradation of metallurgical properties for corrosion specimens removed f ~ o mthe loop containing bismuth has been noted. Operation of a molten-salt reactor wtth a small €raction (less than 1%) of the uranium present as UF3 is advantageous in o ~ d e rto minimize corrosion reactions ana the oxidizing tendency of the fission process. The [u+4]/[U+33 ratio in the MSRE was maintained at the desired level by reduction of ~ + 4with beryllium metal, and a voltametric method for the determination of this ratio in the MSEtE fuel was developed. The finall s t e p in the processing plant will consist bn contin~ouslymeasuring and adjusting the [11+41/[~+31 r a t i o of the f u e l salt returned to the reaCtoK. 3.3.3.6

Actinide separation and recycle

It appears to be desirable to separate the transuranium actinides and recycle these elements to the reactor for transmutation to less undesirable i s o t a p e s in order to m i n f d z e d i f f i c u l t i e s a s s o d a t e d wfth the storage and d i s p o s a l of wastes containing such materials. A preliminary examination of a recycle flowsheet h d i e a t e d that actinide separation and recycle should be possible in a processing plant not significantly more complex than the one presently being considered. t.:...-

TASK GROUP 2.1 FUWSHEET ANALYSIS AND DEVELOPMENT

3.4

Work in t h i s task group is concerned w%th computer analyses of plpo~essing systems, and t h e evaluation and development of processing plant flowsheets. 3 4 1 Obj ective e

The objective 0% this task group is to identify and to develop flawsheets for proeesshg the fuel from a molten-salt reactor which will be optimum with respect to criteria suck as p~acti~abilbty, power costs, K ~ S O U T G ~ utilization, and environmental effects. 3.4 2 0

Schedule

The schedule f o r Task Group 2.1 is shown in Table 3 . 4 . 2 . 3.4.3

Funding

Operating funds required for Task Group 2.1 are shorn in Table 3 . 4 . 3 .

Table 3.4.2.

Schedule for Task Group 2.1 - Flowsheet

analysis

and development

Fiscal -976 2.1.1

Heat balances

2.1.2

Mass balances

2.1.3

Parametric

2.1.4

Waste characterization 2.1.4.1 Waste types and production 2.1.4.2 Waste hazard studies

and optimization

2.1.5

Processing estimate

plant

conceptual

2.1.6

Processing system control 2.1.6.1 Steady state 2.1.6.2 Transients 2.1.6.3 Off-design operation 2.1.6.4 Information required

2.1.7

Resource requirements

2.1.8

Alternate

studies rates

design and cost

for control

and utilization

process development

year 1980

Table

3.4.3.

Operating

budget

far Task Grspup 2.1 - Plowsheet (costs in mm slolla9s)

1975

analysis

and development

1976

197%

19 78

2.1.1

Heat

balances

2.1.2

Mass balances

2.1.3

Parmetric

2.1.4

waste charac2%eKization 2.1.4.1 Waste types and pxaductian rates

2.1.5

and

2.1.4.2

Waste

Subtotal

2.1.4

P~ocessimg

ogtimizat%an

hazard

plant

studies

10 10 20

studies

conceptual

design

and

cost

estimate

2.1.6

Plsocessing system @ontral 2.1.6.1 Steady state 2.1.6,2 Transients 2.1.6.3 2.1.6.4

19 79

Bff-design Pnfomation

operation required

20 10 for

control 40

Subtotal

2.1.6

2.1.7

Resaukce

requirements

2.1.8

Alternate process Bevelopwent

and

utilization

Total Isspe?Yatixng funds fss Task Group 2.1

ao 70

65 105

65 180

65 20Q

1980

3-23

.3.4.4 ...

... &

Task 2.1.1

Heat b a l a n c e s

An e x i s t i n g g e n e r a l compute^ code w i l l b e used and a d d i t i o n a l codes w i l l to~ c a l c u l a t e the ~llnountof C I ~ C Z heat I~ release be developed W P ~ ~ I n I e ~ e s s a f o r each o p e r a t i o n i n t h e processing p l a n t . This work 2 s n e c e s s a r y to determine t h e h e a t t r a n s f e r area r e q u i r e d i n each p i e c e of equipment. Codes based upon e q u i l i b r i u m s t a g e models w i l l b e modified t o allow models i n which mass t r a n s p o r t e f f e c t s predominate. En some cases t h e a l l o w a b l e h e a t release rate will lhdt t h e f i s s i o n p r o d u c t c o n c e n t r a t i o n s ~~ will because of heat removal c o n s i d e r a t i o n s . Decay h e a t g e n e ~ a t i orates be o b t a i n e d from c o n c e n t r a t i o n d a t a de te mine d i n mass b a l a n c e c a l c u l a t i o n s .

3.4.5

Task 2.1.2

Mass b a l a n c e s

For t h e more promising f l o w s h e e t s , mass b a l a n c e c a l c u l a t i o n s will b e made f o r each fissjbon p ~ ~ d u ncutc l i d e and f o r all transuranium isotopes u s i n g t h e computer codes mentioned i n t h e previous s e c t i o n . The mss b a l a n c e c a l c u l a t i o n s w i p l b e coupled w i t h a c a l c u l a t i o n f o r the r e f e r e n c e r e a c t o r d e s i g n i n order t h a t t h e e f f e c t of c a l c u l a t e d removal times and t h e e f f e c t o f r e c y c l e of transuranium i s o t o p e s on t h e r e a c t o r pesfomance cam b e determined. lap1 c a l c u l a t i o n s w i l l b e c o n t i n u a l l y updated as new process d a t a ( e q u i l i b r i a , mass t r a n s f e r c o e f f i c i e n t s , e t c . ) ' B ~ ~ C Q T E a v a i l a b l e .

3.4.6

Task 2.1.3

P a r a m e t r i c and o p t i m i z a t i o n s t u d i e s

The computer code which c a l c u l a t e s mass b a l a n c e s , h e a t g e n e r a t i o n rates, and w a s t e p r o d u c t i o n rates w i l l b e used t o do p a r a m e t r i c studies %n o r d e r t h a t m o d i f i c a t i o n s of t h e r e f e r e n c e flwsheet w i l l r e f l e c t an optimization of the e f f e c t c a w e d by each c h a r a c t e r i s t i c which is s t u d i e d . Parameters to be v a r i e d i n c l u d e reductant c o n c e n t r a t i o n s , salt and bismuth flow rates, and m o d i f i c a t i o n s t o the flowsheet.

3.4.7 3.4.7.1

Task 2.1.4

Waste c h a r a c t e r i z a t i o n

Subtask 2.1.4.1

Waste t y p e s and p r o d u c t i o n rates

The material b a l a n c e c a l c u l a t i o n s using t h e p r e v i o u s l y mentioned computer codes w i l l b e w e d to d e s c r i b e volumes and compositions sf waste stream a s s o c i a t e d w i t h each proposed flawsheet. Waste d i s p o s a l c o n s t d e r a t i o n s a s s o c i a t e d w i t h each f l o w s h e e t w i l l be assessed from these c a l c u l a t i o n s .

3.4.7.2

Subtask 2.1.4.2

Waste h a z a r d s t u d i e s

IORIGEN w i l l For each waste stream, c a l c u l a t i o n s u s i n g t h e C Q I I I ~ U ~ ~ code be meade to determine the activity and waste hazard as a fmnct%sn of time. This subtask is n e c e s s a r y for e v a l u a t i n g the environmental e f f e c t s of %BR o p e r a t i o n , and f o r comparing waste h a z a r d s of %BRBs w i t h waste hazards of o t h e r reactor concepts.

3-24 3.4.8

Task 2.1.5 e sth a t e

P r ~ c e s s i n gp l a n t conceptual d e s i g n and c o s t

For p a r t i c u l a r l y a t t r a c t i v e flmsheets, p r e l i m i n a r y plant d e s i g n s w i l l be performed i n which equipment s i z e s , ~ ~ ~ i t e r iof a l sc o n s t r u c t i o n , heat t r a n s f e r surface areas, line sizesr and p u p s i z e s w i l l b e s p e c i f i e d . Material balance and heat g e n e r a t i o n caPcuPatfons d i s c u s s e d i n p r e v i o u s s e c t i o n s w i l l also serve as the b a s i s f o r these studies i n which p l a n t c o s t s w i l l be e s t i m a t e d .

3.4.9

Task 2.1.6

Processing system c ~ n t ~ 0 1

3.4 9.1

Subtask 2 1 6 k

Steady s t a t e a n a l y s e s

3.4.9.2

Subtask 2.1.6.2

' G ~ ~ ~ n ~ainea lny ts e s

h l p o r t a l l t COntrQl VZiKiableS 8 X E ? i d e n t i f i e d from Steady-State allakyses, t r a n s i e n t a n a l y s e s must b e performed i n o r d e r t o assess t h e s e v e r i t y of c o n t r o l p r o b l e m and t o suggest v a r i o u s m e a n s f o r e f f e c t i n g the desired c o n t r o l . Equipment models which accurately d e s c r i b e time-dependent beh a v i o r would be developed. hcle

3.4.9.3

Subtask 2.1.6.3

E f f e c t s of off-design o p e r a t i o n

gff-design SperatiOHa of the proCeSs~llgplant could r e s u l t from S t % r t U p , undetected equipment failure, and c o n t r o l d i f f i c u l t i e s . f i e consequences of events suck as f a i l u r e of t h e f l u o r i n a t o r t~ remove t h e ~ e q ~ 9 r ef d raction of uranium, i n c r e a s e s im mass t r a n s f e r resistances im salt-metal contactors, changes in flow ratesp e t c . , will be assessed. Actions necessary f o r r e t u r n t o noma1 o p e r a t i o n w f l H b e determined. The e f f e c t on b r e e d i n g perfomance of prolonged o r p e r i o d i c off-design o p e r a t i o n w i l l be assessed.

3.4.9.4

Subtask 2.1.6.4

E n f o m t i o n required f o r c o n t r o l

'&le analyses d e s c r i b e d above w i l l i d e n t i f y those v a r i a b l e s which must be c o n t r o l l e d and the degree of c o n t r o l ~ e ~ p ~ i r e Q d u. a n t i t i e s which can be measured and w e d as c o n t r o l s i g n a l s w i l l b e i d e n t i f i e d .

3.4.18

Task 2.1.7

Resource requirements and u t i l i z a t i o n

The f l o w s h e e t a n a l y s e s wh%& have been d i s c u s s e d wibPl allow the i d e n t i f i c a t i o n sf the requirements f o r a l l material used i n t h e constructPon

w...

3-25

and o p e r a t i o n of a n MSBR p r o c e s s i n g p l a n t . These material requirements w i l l b e compared t o p r o j e c t i o n s of domestic and world r e s o u r c e s and reserves sf t h e s e materials i n o r d e r t o i d e n t i f y any materials t h a t are l i k e l y t o lMt a g r o ~ i n gW B R i n d u s t r y , and a l l o w €or any n e c e s s a r y ~ ~ ~ o d i f i c a t i on no r d e r t o a v o i d a s i g n i f i c a n t SOUKC KC^ l i m i t a t i o n .

3.4.11

Task 2.1.8

A l t e r n a t e p r o c e s s development

The c u r r e n t r e f e r e n c e p r o c e s s i n g f l o w s h e e t c o n ~ i s t sof a sequence of o p e r a t i o n s , t h e f a i l u r e of any one of which h a s a s i g n i f i c a n t e f f e c t on t h e o v e r a l l p r o c e s s i n g e f f i c i e n c y . Moreover, a l t e r n a t i v e s do n o t p r e s e n t l y exist f o r most of t h e processing s t e p s . It i s t h e o b j e c t i v e of this t a s k t o d e f i n e a l t e r n a t e s f o r each of the p ~ o c e s s i n gs t e p s and, if p o s s i b l e , d e f i n e a completely new and d i f f e r e n t p r o c e s s i n g scheme. I n i t i a l l y , t h e e f f o r t i n t h i s t a s k w i l l b e devoted t o it thorough review of t h e p e r t i n e n t l i t e r a t u r e r e l a t i n g t o t h e c h e m i ~ t ~ofy p r o t a c t i n i u m and fission p r o d u c t s i n molten f l u o r i d e salts. Hopefully, i d e a s f o r new s e p a r a t i o n s methods w i l l be generated. Concurrently, p r e l i m f n a ~ y l a b o r a t o r y s t u d i e s of p o t e n t i a l s o r p t i o n and ion-exchange processes will be made. I f a t t r a c t i v e a l t e r n a t e s are d e f i n e d , t h e y will be emphasized i n f u ~ t h e rwork.

3.5

.... w

.:.s

..&

TASK GROUP 2.2

CONTINUQUS FLUORINATOR DEVELOPMENT

T h i s t a s k group c o v e r s a c t i v i t i e s ~ ~ ~ e s f so ra the ~ ydevelopment of technology r e l a t e d to t h e continuous removal of uranium from MSBB f u e l s a l t by c o n t a c t w i t h e l e m e n t a l f l u o r i n e . The i n i t i a l work i s concerned w i t h t h e development of a u t s r e a i s t a n e e h e a t i n g methods f o r s i m u l a t i n g h e a t g e n e r a t i o n r e s u l t i n g from f i s s i o n p r o d u c t decay i n f l u s r i m t o r s , and w i t h the s t u d y s f t h e f l u o r i n a t i o n chemistry of uranium and o t h e r elements which can be o x i d i z e d to h i g h e r v a l e n c e states by c o n t a c t with f l u o r i n e . Subsequent work is r e l a t e d t o the d e s i g n , ~ ~ n s t ~ u c t iand on o p e r a t i o n of a f a c i l i t y f o r e n g i n e e r i n g development and testing of cont i n u o u s f l u o r i n a t o r s . The task group c a r h i n a t e s in t h e d e s i g n , conseruction, and o p e r a t i o n sf a f a c i l i t y f o r e n g i n e e r i n g development and t e s t i n g of equipment i n which t h e removal of uranium from WBW f u e l s a l t by f l u o r i n a t i o n and t h e recombination of uranum w i t h MSBR f u e l carrier s a l t can b e c a r r i e d o u t s i m u l t a n e o u s l y .

1 I

3.5.1

Objective

The o b j e c t i v e of t h i s t a s k group is t o develop the technology r e q u i r e d f o r the d e s i g n of f l u o r i n a t o r s f o r t h e continuous removal sf uranium from s a l t streams i n MSBR p r o c e s s i n g systems.

3.5.2

Schedule

The s e h e d u l e f o r Task Group 2 . 2 is shorn i n Table 3.5.2.

2.2.B 2.2.2

2.2.3 2.2,4 2.2.5 2.2.6

---

2.2.7

3-27

3.5.3

Funding

Operating funds required f o r Task Group 2.2 are shorn i n Table 3 . 5 . 3 . Capital equipment funds are required i n t h e amounts of $50,000 during FY 1975 f o r design and construction of t h e Continuous Fluorinator E q e r i n e n t a l F a c i l i t y and of $125,QOQ d u r i n g 1976 f o r covering h a l f of t h e c o s t of t h e F l u o r i ~ a t i o n - R e c o n s t i t u t i o n Engineering F a c i l i t y . The remaining c o s t of t h i s f a c i l i t y i s covered i n Task Group 2.3. Capital equipment funds i n t h e amount of $75,880 w i l l be required during l?Y 1 9 7 6 to provide automatic data-logging equipment f o r t h e F l ~ ~ r i n a t f o n Reconstitution Engineering F a c i l i t y .

3.5.4

Facilities

A Continuous Fluorinator F a c i l i t y i s planned for i n s t a l l a t i o n i n Bldg. 4505 a t ORNL. This f a c i l i t y will be used f o r study and demonstration of continuous f l u o r i n a t i o n from rdd FY 1976 thrsugh E'Y 1977, and w i l l r e q u i r e a c a p i t a l equipment o b l i g a t i o n of $50,000 i n R 1995. Ita t h i s facility, a frozen-wall continuous f l u o r i n a t o r would be operated t h a t has a molten z ~ n ediameter of 5 in. and a height of about 5 f t . The f a c i l i t y w i l l operate with salt and f l u o r i n e flow rates up t o 50% of those required i n a 1000-W(e) mBW. A Pluorination-Recombination Engineering F a c i l i t y i s planned €OK i n s t a l l a t i o n i n Bldg. 7503 a t ORNL f o r study and demonstration of t h e i n t e g r a t e d

operations of f l u o r i n a t i o n and f u e l r e c o n s t i t u t i o n using f l o w rates t h a t are about 50% of those required f o r a lQBCB-IVIW(e) MSBR, The f a c i l i t y w i l l operate from mid-m 1977 through E T 1978. This f a c i l i t y i s a l s o discussed i n Task Group 2 . 3 Fuel Reconstitution under Task 2 . 3 . 3 F l ~ o r h a t i ~ n Reconstitution E n g i n e e ~ i n gFacility.

The f l u ~ r f n a t o rw i l l be an open bubble column made of n i c k e l having a frozen l a y e r of s a l t on t h e w a l l s t o p r o t e c t a g a i n s t corrosion by fluor i n e . An i n t e r n a l h e a t source i s necessary f o r maintaining t h e frozen s a l t layer. F i s s i o n p r ~ d u c tdecay will provide t h i s heat source i n t h e processing p l a n t , but i n i n i t i a l experiments where no r a d i o a c t i v e heat source is a v a i l a b l e another means must be found. This task would provide a heat source which can be used i n nonradioactive experiments t o study f l u o r i n a t i o n i n f r ~ z e nw a l l f l u s r i n a t s r s . Studies of a u t o r e s i s t a n c e heating must be done t o demonstrate t h e o p e r a b i l i t y sf an e l e c t r o d e s i d e a m design on a f l u o r i n a t o r mockup and the a b i l i t y t o maintain s t a b l e salt f i l m using the LiP-BeF2-ThF4 s a l t mixture. Experiments with p r e s e n t l y i n s t a l l e d equipment i n d i c a t e s that the wall temperature must be held efgniffcant.ly Pmer than t h e temp e r a t u r e for which t h i s equipment w a s designed. Experimental equipment w i l l be designed which will allow e x t e r n a l h e a t i n and r e c i r c u l a t i o n of

---

Table 3.5.3.

- --

Qperating

budget folp Task GlPaup 2.2 - @ontlnuaus fluarinatar (casts in 1000 dollars) Fiscal 1975

2.2.1

Nanradiaactfve

2.2.2

Fluarinatian chemistry 2.2.2.1 UKanium removal 2.2.2.2 Fllxxhatisn chemistry other than uranium Subtotal

heat genePati0r-l studies

50 70

Mass transfer

in open bubble columns

2.2.5

F~"M~ reaction

khetics

2.2.6

Continuous Fluorinator Experimental Facility 2.2.6.1 Conceptual design and experimental

2.2.4

corrosion

Final design Fabrication, installation, Operation

Subtotal

2.2.6

1978

65 65

60 60

pKOgSCEQ

2.2.6.2 2.2.6.3 2.2.6.4

1977

studies

Frozen-walP

year

of elements

2.2.2

2.2.3

1976

development

and testing

15 73 5 93

II.5 230 245

200 266

1979

ci.

Table

3.5.3

(continued) Fiscal 1975

2.2.7

Fluorination-Reconstitution Engineering Facility 2.2.7.1 Conceptual design and experimental program 2.2.7.2 Development required for final design Final design 2.2.7.3 Fabrication, installation, and testing 2.2.7.4 2.2.7.5 Operation Subtotal

Total

operating

10 4

2.2.7

funds

222

for

Task

Group

2.2

1976

40 30 70

455

year 1977

10 20 80

110 375

1978

18Q 180 240

1979

3-30

3.5.6

Task 2.2.2

Fluorination c h e ~ s t q

. . .....

The o b j e c t i v e of this subtask is to d e f i n e t h e b e h a v i o r d u r i n g f l u ~ ~ i n a t i o n of elements that are p r e s e n t in the s a l t only at l o w concentration. Of p a r t i c u l a r interest are p r o t a c t i n i u m , neptunium, plutonium, oxygen and iodine which fsm v o l a t i l e f l u o r i d e s under some c o n d i t i o n s . The f2Xt6Z!n% t o Which SUCh deEVXlts foKTD Volatile fluOKides Under OptiHnal c o n d i t i o n s f o r uranium removal will be determined. The oxidation states of these fluorides w i l l b e identified, s i n c e this b o w l e d g e i s required in d e f i n i n g eke ehexLstryr of the subsequent fuel. r e s o n s t i t u t ~ - o n step 0

3-31

.:.&

There are good reasons f o r believing t h a t f r o z e n salt f i l m s w i l l 1 p r o t e c t a g a i n s t corrosion, but this h a s not y e t been demonstrated. An experiment w i l l be performed i n whfch a f r o z e n s a l t f i l m i s formed on a n i c k e l t u b e through which f l u o r i n e can be sparged i n t o molten s a l t . T h i s work req u i r e s t h e i n s t a l l a t i o n of a f l u o r i n e supply system and a f l u o r i n e d i g posal system. I n s t a l l a t i o n of t h e s e systems i s i n p ~ o g r e s s .

3.5.8

... .Z<&

.... ....

,.w

Task 2.2.4

Mass t r a n s f e r i n open bubble C S ~ U ~ ~ B S

The o b j e c t i v e of t h i s t a s k i s to p r ~ ~ f b d aes i c desdgn d a t a upon which i n i t i a l d e s i g n s of open bubble columns o p e r a t i n g w i t h molten-sa%t systems can be based. Later designs w i l l b e based upon t h i s d a t a p l u s a c t u a l o p e r a t i n g d a t a o b t a i n e d w i t h m o l t e n - s a l t systems. Paass t r a n s f e r c o e f f i c i e n t s will be measured i n air-aqueous s o l u t i o n syst e m s i n o r d e r t o p r o v i d e c o r r e l a t i o n s f o r e s t i m a t i n g uranium removal rate and f l u o r i n e u t i l i z a t i o n i n t h e f l u o r i n a t o r . Mass transfer c o e f f i c i e n t s which are c o r r e c t e d for end e f f e c t s and f o r a x i a l d i s p e ~ s i o nw i l l be measured i n g l a s s bubble columns f o r t h e bubble flow and the slug flow regimes and for varying physical properties of t h e l i q u i d phase. End e f f e c t s are important and methods f o r e s t i m a t i n g the magnitude of end e f f e c t s will be i n v e s t i g a t e d .

3.5.9

Task 2.2.5

C h a r a c t e r i z a t i o n of t h e F Z - H ~r e a c t i o n

Fluorine and hydrogen gases will b e mixed i n a reaeticon v e s s e l a t Bow temperatures and p r e s s u r e s . These mixtures w i l l be p r e s s u r i z e d a t cons t a n t t e m p e r a t u r e o r heated a t eonstant pressure until reaction o c c u r s i n order t o define t h e l i m i t s of spontaneous reaction of mixtures of d i f f e r e n t compositions. Nonreactive P2-l-l~ m i x t u r e s w i l l b e exposed t o i g n i t i o n s o u r c e s of v a r y i n g types ( t h e presence of atomic f l u o r i n e , r a d i a t i o n , s p a r k , l i g h t , e t c . ) i n o r d e r t o determine t h e e f f e c t of i g n i t i o n source.

3.5.10

Task 2.2.6

Continuous F l u o r i n a t o r hperimentiil F a c i l i t y

I 1

The o b j e c t i v e of t h i s w ~ r kis t o propride a facility w i t h which continuous frozen-wall f l u o r h a t o r s can be t e s t e d .

I I

3-32

Subtask 2.2.6.1

3.5.10.1

Definition of experimental program and

The work is this subtask will be directed to defining the experimental program and completing the conceptual design for t h e Continuous P l u o r i nator E q e r i m e n t a L Facility. me experiments carried out in thLs facility will have the objectives of (1) demonstrating frozen wall corrosfon protection cOntiatlllOUs fluOrinatOPS, (%> ItEaSuPing the e f f e c t O f Qpe'P:atillg conditions on F2 utilization, ( 3 ) measuring the effect of o p e r a t i n g sonditione on uranium removal efficiency, and ( 4 ) corroborating the correlations derived from air-water measurements. The effect on F2 utilization and U removal efficiency of t h e following variables will be measured: gas flow ratep liquid f l o w rate, temperature, and concentration of UP4 in the salt. Following the f b u ~ r i n a t i ~experiments, n the facility will be used to study reconstitution of UP6 which is mixed with fluorine in order to test methods s f fuel reconstitution Which do not require sepalratiobl O f the and f l u o r i n e . Frozen wall C O K K O S ~ Oprotection ~ will be required.

Equipment f o r t h e experhent will i n c l u d e a fluoride salt surge tank, a f l u o r i n a t o r , a sa1t-hydroge1-1 c o n t a c t o r , UP6 collection and fluorine d i s p o s a k system, means f o p determining the concentration in the fluorinator o f f g a s , and means f o r sanpling the salt streams present in the system. Salt containing UF, will be withdram from the surge tank and fed to t h e f P u O K i T l a t o K Where p a r t sf the UPaniUD W i l l be removed as UFg. The s a l t leaving t h e fluorinator will be f e d to the hydro s a l t eontactor for reduction of uranium fluorides to UP4 before th is returned to the surge tank. Salt will be circulated through the s y s tem at flow rates in the range 8 . 3 to 3 lfters/min. me fluoride salt e tank volume (about 5 f t 3 ) is sufficiently large that the uranium COncentkatiOn ill the S a l t f e d to the flUQrf.natOP will Vary QVC'P: 8 Useful Co€Epo§itiobt range (appKOXilWite%y 0.35 mOlf2 2 to 0.86035 Illole %> in about 3 Ear at a molten s a l t flow rate sf about 1. literlmin. The fluorinator will consist of a 6-in.-OB vessel which will be heated by a u t o r e s i s t ~ ~ - ~ ~ e heating using 6 0 - H Z power. The molten s a l t zone will be about 4.5-in. in d i m and t h e s a l t depth in the f l u o r i n a t o r w i l l be about 6 f t * Conceptual design of this facility will consist of a choice of the scale of equipment, identificatfon of auxiliary equipment (gas supplies, excess reagent and waste d i s p o s a l systems, instrumentation calibration stations, et^.), location of equipment, and preliminary design and layout sf equipment 0

3.5.18.2

Subtask 2 . 2 . 6 . 2

Final design

The final design of t h e facility will involve detailed a n a l y s i s a d calculations required to ensure that the facility will meet the desired objectives and t h a t experiments which wlbll be performed will prsvfde the necessary i n f o m a t i o n . !I%emla d mechanical stresses will be evaluated a d m.tnta%ned within allowable limits. Instrumentation and control systems will be designed to provide information and ne~e~~a1-4p control action. me final d e s i ll wf%%. lbesclekde proVfsfOns for eqUipTileI'lt lMfnte~EUlCE2, 332placement, or modification.

&..

3-33

3.5.10.3

subtask 2 . 2 . 6 . 3 testing

F a b r i c a t i o n , installation and i n i t i a l

C o n s t r u c t i o n of t h e f a c i l i t y w i l l b e Q u a l i t y Level III and a q u a l i t y a s s u r a n c e p l a n w i l l be prepared i n accordance with OREX q u a l i t y a s s u r ance procedure QA-L-1-104.

,..u

Following installation of t h e f a c i l i t y , t h e system will b e l e a k cheeked and s a l t will b e charged t o t h e experiment. I n i t i a l t e s t i n g w i l l i n c l u d e ~ O R maintenance of the f r o z e n wall, and r e c i r c u l a t i o n of s a l t , ~ Q Y X R ~ ~and c a l f b r a t i o n of s p e c i a l i n s t r u m e n t a t i o n ( s a l t flow meters, gas ehromatog r a p h s , e t c . ) . A d e t a i l e d s a f e t y a n a l y s i s will be prepared b e f o r e o p e r a t i o n of t h e f a c i l i t y . P r i o r t o s t a r t u p d e t a i l e d check l i s t s will b e p r e p a r e d f o r t h e f o l l o w i n g o p e r a t i o n s : (1) s t a r t u p and shutdown of f l u o r i n e supply system; ( 2 ) startup and ~hutdowtlof t h e f l u o r i n e d i s p o s a l system; ( 3 ) o p e r a t i o n of i n s t r u mentation; ( 4 ) s a l t sampling; (5) o p e r a t i o n of t h e UFQ d i s p o s a l system; ( 6 ) o p e r a t i o n of t h e hydrogen supply system; (7) formation of f r o z e n salt f i l m ; and (8) s a l t r e c i r c u l a t i o n and d r a i n a g e .

3.5.10.4

r.&....

,..&

Subtask 2 . 2 . 6 . 4

Operation

The Continuous F l u o r i n a t i o n Experimental F a c i l i t y w i l l b e o p e r a t e d d u r i n g t h e p e r i o d from mid PY 1976 t o wid FY 1977 i n o r d e r t o develop t h e technology r e q u i r e d f o r t h e subsequent d e s i g n of t h e FPuorination-Reconstitutisn Engineering F a c i l i t y , and t o p r o v i d e improved d a t a on f l u o r i n a t o r p e r f o r mance f o r p r o c e s s i n g p l a n t c o n c e p t u a l d e s i g n and c o s t e s t i m a t i o n s t u d i e s . A l t e r n a t e f l u o r i n a t o r d e s i g n s w i l l b e t e s t e d as r e q u i r e d . S u f f i c i e n t d a t a w i l l b e o b t a i n e d t o show t h e p r a c t i c a b i l i t y of frozen-wall f 1 ~ 1 - i nator operation.

The o b j e c t i v e of t h i s t a s k i s t o p r o v i d e a f a c i l i t y i n which t h e operat i o n of a continuous f l u o r i n a t o r and equipment f o r f u e l r e c o n s t i t u t i o n can b e i n t e g r a t e d i n o r d e r t o d e t e r m i n e o p e r a t i n g c h a r a c t e r i s t i c s for the combined s t e p s , t o evaluate c o n t r o l methods, andl t o determine t h e e x t e n t t o which s u r g e c a p a c i t y must b e provided between t h e two operations. S u f f i c i e n t i n f o r m a t i o n w i l l b e o b t a i n e d t o allow d e s i g n of t h e fluorination-reconstitutisn systems for t h e I n t e g r a t e d Process T e s t F a c i l i t y as w e l l as f o r t h e t e s t r e a c t o r mockup.

This f a c i l i t y w i l l a l l o w t h e t e s t i n g o f f l u o r h a t o r s which w i l l o p e r a t e under c o n d i t i o n s very s i m i l a r t o t h o s e expected i n a p r o c e s s i n g p l a n t . The f l w r i n a t o r s i n t h i s f a c i l i t y w i l l b e designed f o r much h i g h e r uranium removal efficiences (>99%) than will be p o s s i b l e in the Continuous F l u o r i n a t o r Experimental F a c i l i t y (80-30%).

The i n f o r m a t i o n t o be determined from t h i s f a c i l i t y is a s s o c i a t e d w i t h long-term o p e r a b i l i t y and c o n t r o l of continuous frozen-wall f l u o r h a t o r s . Emphasis w i l l be

3-3 4

placed upon frozen film stability and i n t e g r i t y , accurate corrosion measurements and maintenance sf high uraniuna removal efficiency and fluorine u t i l i z a t % o n .

3 6.1 0

Bbj ective

The objective of t h i s task group is to provide the technology necessary f o r design of equipment f o r recombining UFg generated in the fhusrinatsrs in the processing plant with the processed fuel s a l t stream returning to the reactor to produce a s a l t mixture having the proper uranium concentration. 3 6 2

Schedule

3.6.3

Funding

Table 3.6.2.

Schedule far Task Group 2.3 - Fuel reconstitution Fiscal

2.3.1

Fuel recanstitutian chemistry 2.3.1.1 uranium chemkstry 2.3.1.2 Chemistry of other volatile studies

of fuel

fluorides

2.3.2

Engineerfng

reconstitution

2.3.3

Fluorination-Recarastitut~~.an Engineering Facility 2.3.3.1 Comeptual design and experimental pr0grt3.m

2.3.3.2 2.3.3.3 2.3.3.4 2.3.3.5

Development for final design Final design Fabrication installatlsn and testing Operation

year

Table 3.6.3.

Opel-sting budget for Task Group 2.3 - Fuel Pecan%titutisn (costs in 1000 dollars) Fiscal

2.3.1

Fuel Keconstitution chemfst~ 2.3.1.1 UKanium &emistEy 2.3.1.2 Chemistq of other vol_atile Subtstal

1976

1977

l-978

55 55

30 20 50

65 65

55 55

139

10 15 80 1__ 105 17Q

188 180 235

2.3.1

Engineering

2.3.3

FlnQrination-Racsnstitutian Engineering Facility 2.3,3-l Canceptwl design and experimental pogram Development for find design 2.3.3.2 Final design 2.3.3.3 2.3.3.4 Fabrfcatisn installation and testing 2.3.3.5 operation

Total

1975

fluorides

2.3.2

studies

of fuel

reconstitution

Subtotal

2.3.3

operating

funds far Task Group 2.3

year

5 2

7 ~ 152

40 30 ___ 70 259

1979

3-37 ...... &

3.6.4 & ;....

.... .... ... .:.?a

Facilities

A Fluorination-Reconstitution

Engineerhg F a c i l i t y i s planned f o r i n s t a l l a t i o n i n Bldg. 7503 f o r study and demonstration of t h e i n t e g r a t e d opera t i o n s of f l u o r i n a t i o n and r e c o n s t i t u t i o n using flow rates t h a t are about 50% a€ those required f o r processing a 1000-MWQe) MSBR. The f a c i l i t y w i l l operate from l a t e FJI 1977 through IFSI 1978. This f a c i l i t y i n t e r f a c e s with Task Group 2.2, Continuous Fluorinator Development.

q.... &.

...

3.6.5 ...

.52a

Task 2.3.1

Fuel r e c o n s t i t u t i o n chemistry

The o b j e c t i v e of t h i s t a s k i s t o determine t h e f u e l r e c o n s t i t u t i o n chemistry of uranium and other elements which form v o l a t i l e f l u o r i d e s during f l u o r i n a t i o n including neptunium, plutonium, and iodine.

3.6.5.11

Subtask 2.3.1.1

Uranium chemistry

The o b j e c t i v e of t h i s subtask is t o e l u c i d a t e t h e chemistry of t h e react i o n s of gaseous UFg and f l u o r i n e with UP4 dissolved i n MSBR fuel s a l t and t h e subsequent reduction of t h e product UP5 by hydrogen. Previous work has shown t h a t t h e primary r e a c t i o n s are

....xL

but t h a t some UFg i s v o l a t i l i z e d from t h e melt according t o .....

,.X,L,

&& .

Estimates of t h e equilibrium constant for these reactions w i l l be made t o aid i n t h e design of engineering-scale equipment f o r fuel reconst%tution studies.

(

Previous work has also shown t h a t t h e r e a c t i o n

UFg(d) .... ..... ..., ,..=

+ 1/2 HzCg) = UFk(d) + HF(g)

is slower than t h e UFs absorption r e a c t i o n s . Information on t h e k i n e t i c s of t h i s r e a c t i o n w i l l be obtained. Of p a r t i c u l a r i n t e r e s t are t h e d e t e r -

mination of t h e r a t e - c o n t r o l l i n g s t e p and t h e e f f e c t of temperature on the r e a c t i o n rate. $3

3.4.5.2

Subtask 2.3.1.2

Chemistry of o t h e r v o l a t i l e f l u o r i d e s !

The o b j e c t i v e of this subtask i s t o e l u c i d a t e t h e chemistry of such volat i l e f l u o r i d e s as E?pF6> PuPs, 8P2 and IF7 i n t h e f u e l r e c o n s t i t u t i o n s t e p .

3-38

3.6.4

Task 2 . 3 . 2

Engineering studies of fuel resonstitutfon

The o b j e c t i v e of this taSk is to provide a facility in which the operat i o n sf a CoRtirakaOUS flUOrinatOr and equipmC%l% f O P f u e l K@cCKStitUtion rated in order to deternine operatin C!har%ct€%iS%ieS for the combined s t e p s , t o evaluate c o n t r o l methods, and t o deternine the extent to which surge capacity mst be provided betweem the t w o operations. Sufficient i n f o m a t i o n will be obtained to allow design of flusPEnation-9econstit~t~onsystem for the %wtegrat@dProcess Test FaciHity and f o r the test reastor ElOCkUP.

3-39

3.6.7.1

Subtask 2.3.3.1 D e f i n i t i o n of experimental p r o g r m and conceptual design

The r e c o n s t i t u t i o n experiments c a r r i e d o u t i n t h i s f a c i l i t y w i l l have t h e folbowing object2ves: (1) t o deternine i f uranium l o s s e s can occur d u r i n g long-term o p e r a t i o n , (2) to t e s t t h e e f f e c t s of u s i n g r e c y c l e streams i n t h e r e c o n s t i t u t i o n s t e p , (2) t o d e t e r m i n e t h e need f o r s u r g e c a p a c i t y between o p e r a t i o n s , ( 4 ) to d e t e r m i n e long-term c o r r o s i o n rates, and ( 5 ) t o test o p e r a b i l i t y of combined p r o c e s s e s . T h i s f a c i l i t y w i l l be l o c a t e d i n B1dg. 7582 (MS B u i l d i n g ) . Conceptual d e s i g n will c o n s i s t of a c h o i c e of t h e scale of t h e equipment, i d e n t i f i c a t i o n of a u x i l i a r y equipment (gas s u p p l i e s , excess r e a g e n t and waste d i s p o s a l systems, i n s t r u m e n t a t i o n c a l i b r a t i o n s t a t i o n s , e t c . ) , and p r e l i m i n a r y d e s i g n and l a y o u t of equipment c o n s i s t e n t wFth experimental o b j e c t i v e s . The B K ~ B S whish w i l l r e q u i r e development work b e f o r e completing t h e f i n a l d e s i g n w i l l be i d e n t i f i e d .

3.6,7.2 .........

Subtask 2 . 3 . 3 . 2

Development work ~ e q ~ i r ef od r f i n a l d e s i g n

....1

P l a n s f o r r e q u i r e d development w i l l b e d e t a i l e d , and s c h e d u l e s determined which are consistenst w i t h t h e o v e r a l l s c h e d u l e f o r t h i s t a s k .

.&.S

3.6.9.3

Subtask 2 . 3 . 3 . 3

F i n a l design

The f i n a l d e s i g n of t h e f a c i l i t y w i l l i n v o l v e d e t a i l e d a n a l y s e s and

. H ,

c a l c u 1 a t i o n s r e q u i r e d to e n s u r e t h a t t h e f a c i l i t y w i l l m e e t t h e object i v e s and t h a t experiments which w i l l b e performed i n i t will p r o v i d e t h e n e c e s s a r y i n f o r m a t i o n . Thermal and mechanical stresses will b e maintained w i t h i n a l l o w a b l e l i m i t s . I n s t r u m e n t a t i o n and c o n t r o l systems w i l l be designed t o p r o v i d e i n f o r m a t i o n and n e c e s s a r y c o n t r o l acti~n. The f i n a l d e s i g n w i l l i n c l u d e p r o v i s i o n s f o r equipment maintenance, replacement, o r m o d i f i c a t i o n .

3.6.7.4

..d

Subtask 2 . 3 . 3 . 4

F a b r i c a t i o n , i n s t a l l a t i o n , and i n i t i a l . testing

C o n s t r u c t i o n of t h e facflity xdll b e t o Quality Level 111 s t a n d a r d s and a quallety a s s u r a n c e plan w i l l be prepared i n accordance w i t h OR& q u a l i t y a s s u r a n c e procedure QA-L-1-104. Fallowing i n s t a l l a t i o n of t h e f a c i l i t y , t h e system will b e leak checked and salt w i l l be charged t o t h e experiment. I n i t i a l testgang w i l l i n c l u d e r e c i r c u l a t i o n of s a l t a t rates up to t h e d e s i g n l i m i t , f o r m a t i o n of f r o z e n w a l l s where r e q u i r e d , and c a l i b r a t i o n of s p e c i a l i n s t r u m e n t a t i o n (salt flow meters, gas chromatographs, etc.). A d e t a i l e d s a f e t y a~tllqpsis w i l l be prepared.

,*.....

..;.;$..

P r i o r t o startup d e t a i l e d check lists will be prepared f o r t h e fallowlnag (1) s t a r t u p s a d shutdown of the f l u s r i n e supply system; operations:

=..... x,.:

3-40

(2) startup and shutdown of t h e f l u o r i n e d i s p o s a l system; ( 3 ) o p e r a t i o n instKUEM2lltatiOn; ( 4 ) salt Salllplhg; (58) OpeKatAon Of the hgrdk5geIl supply system; ( 6 ) formation of f r o z e n s a l t f i l m ; and (7) s a l t r e c i r c u l a t i o n and drainage.

3.6.7.5

Subtask 2.3.3.5

Operation

The Fluorination-Reconstitution Engineering F a c i l i t y wlll be operated . 1978 i n order to develop t h e technology from l a t e I T 1977 t h r o ~ g l s PY required f o r t h e subsequent design of t h e a s s o c i a t e d gortigans of t h e I n t e g r a t e d Process Test F a c i l i t y , and t o provide i m p ~ ~ v edda t a on f l u o ~ i n a t i o nand recon~tit~tion equipment performance f a r processing plant conceptual design and c o s t e s t i m a t i o n s t u d i e s . A l t e r n a t e equipment designs for the p r h ~ oy p e r a t i o n s of fluorinatfon and r e c o n s t i S u f f i c i e n t information w i l l be t u t i o n will be t e s t e d as required. t y t h e combined f l ~ o ~ h a t i o n obtained to show t h e p ~ a c t i ~ a b i l i of recsrastitut%on s t e p s .

&.:.A

This task group covers a c t i v i t i e s necessary f o r t h e development 0% teChnQlOgY r e l a t e d to the IfE?ElOVal Of p P o t a C t k h l f K Q 5 l MSBa f u e l Salt by selective e x t r a c t i o n i n t o l i q u i d bismuth containing r e d u ~ t a n t . The in%tiaP work i s c o t a c e r ~ w ~ li t h study of m a s s t r a n s f e r and h y d ~ o d p a ~ ~ i c s i n salt-metal c o n t a c t o r s , and w i t h t h e development of equipment f o r hydrcBfluOPhatfng O'BT h)PdkoChl0Kbating EM3ltkXl salts the p%eSea%CeOf l i q u i d bismuth. Subsequent work i s r e l a t e d t o t h e d e s i g n , construction, and o p e r a t i ~ nof a f a c i l i t y f o r engineering development and t e s t i n g of components I I ~ C X S S E ~ K ~f o r p r o t a ~ t h i u r nremoval. The t a s k g~op1p culminates i n the design, c o n s t r u c t i o n , and operation of a small engimeering experent that w i l l use r e p r e s e n t a t i v e concentrations of 23 l ~ a(an e n e r g e t i c alpha emitter) f o r demonstrating a l l steps i n the p~otactiniurnremoval OpeKatiOfa.

3.7.1

Objective

3.7.2

Schedule

The schedule f o r c a r r y i n g out Task Group 2.4 i s shown in Table 3.7.2.

h..

Fiscal 1975 2.4.1.

Salt-metal 2.4.1.1 2.4.1.2

contactor Mass transfer metal. Hydrodynamics studies

2.4.2

Engineering studies and hydrochlorination

2.4.3

Reductive 2.4.3.1 2.4.3.2 2.4.3.3 2.4.4.4 2.4.3.5

2.4.4

development studies

with

1980

1976

salt-

and mass

transfer -.

of hydrofluorination

Extraction Process Facility Conceptual. design and experimental program Development for final design Final design Fabrication, installation, and testing Operation

Protactinium Isolation Demonstration Experiment 2.4.4.1 Modification of cell 2 2.4.4.2 Conceptual. design and experimental program 2.4.4.3 Development for final design 2.4.4.4 Final. design 2.4.4.5 Fabrication, installation, and testing 2.4.4.6 Operation 2.4.4.7 Equipment disposal and Pa recovery

year

3-42

3.7.3

Fumdiatg

The program w i l l r e q u i r e alpha containment s p a c e f o r t h e P r o t a c t i n i u m Isolation Denonstration Experiment. T h i s space will be provided by c o n v e r t i n g cell 2, Bldg. 3019, into a m u l t i l e v e l a l p h a f a c i l i t y . GPP funds i n the amount of $355,880 wfll be r e q u i r e d i n e a r l y Fu 1976 for this m d i f i c a t i o n e

3.7.4

Facilities .... u.:.:<,

A Reductive Extraction Process Facility w i l l be i n s t a l l e d in Bldg. 7583 for s t u d y and demonstration of ala. steps of protactinium rmsval w i t h flow rates t h a t are 25% of t h o s e r e q u i r e d f o r a 1 6 0 B - ~ ( e ) MSBW. This f a c i l i t y will o p e r a t e from e a r l y IT 1977 t o a i d PY 1978. A c a p i t a l equipment obligation sf $190,8140 is r e q u i r e d i n PY 1976 f o r csnatruction of t h i s f a c i l i t y . A P r o t a c t i n i u m Isolation Demonstration Experiment would be i n s t a l l e d in Cell 2 in B l d 3019 t o demonstrate a l l process s t e p s for t h e removal from f u e l s a l t u f n g r e p r e s e n t a t i v e concentrations 0% prstaetinium. This demonstration w i l l be i n i n late 1977 and end i n e a r l y Ff 1979. W capital equipment obligation of $480,080 is r e q u i r e d d u r i n g F?f 1977. a

3.7.5

Task 2.4.1

Salt-metal contactor development

The ObjeetiVe sf %hi§ task k %O PrQVidE! t h e techXlQlogy P@qUEred f o r designing equipment f o r contacting molten salt and I I I Q ~ ~ ~bismuth ZI in o r d e r t o carry o u t the transfer sf p r o t a c t i n i u m from s a l t streme i n t o bismuth streams. The equipment which is developed must not be ~nreasonab1yl a r g e ; and must n o t b e expensive t o fabricate.

3.7.5.1

Subtask 2.4.1.1

k s s t r a n s f e r i n a s t i r r e d interface contactor

~easurementof mass transfer rates of 2 3 ’ ~ and 9 ’ ~ r tracers between f ~ u o r i d e f u e l carrier s a l t and bismuth will be continued in a nondispersed s t i r r e d f n t e ~ f a c ec o n t a c b ~ ri n s t a l l e d in t h e S a l t / B i s m t h Flow-Througk Facility. These r e s u l t s w i l l pernit t h e e v a l u a t i o n of eontactors of

.... E = ..

Table _3.7.3. ---

Operating

budget for Task Group 2.4 - Protactinium (costs in lOQO dsPlars) Fiscal 19 75

2.4.1

Salt-metal contactor development 2.4.1.1 Mass transfer studies with salt-metal 2.4.1.2 Hydrodynamics and mass transfer Subtotal

2.4.2

2.4.3

2.4-I

Reductive 2.4.3.1

6af hydrofluorination

2.4.3.4

2.4.4

1977

1978

30 178 -

I.05 ~

288

105

and 2Q

Extraction Process Facility Conceptual design and experimental pr0gC3m

2.4.3.2 2.4.3.3

year

StUdieS

Engineering studies hydrochforination

1976

removal

Development for final Final

design

48 81

design

2.4.3.5

Fabrication, Operation

Subtotal

2.4.3

lnstallatisn,

and testing

Brotactinlum Isolation Demonstration Experiment Modification of cell 2 Conceptual design and experimental pragram 2.4.4.3 Development for final design 2.4.4.4 Final design 2.4.4.5 Fabrication, installation, and testing

I.29

2.4.4.1 2.4.4.2

35 65 40

140

25 1Q

90 78

35 7Q

1979

1980

Table

2.4.4.6 2.4.4.7

Total

sperating

Operation Equipment

disposal

Subtotal

2.4.4

funds

for

3.7.3

(continued)

PQQ

Task

Group

and Pa recovery

2.4

35 219

176 366

285 485

240 15 255 360

25 25 25

3-45 t h i s t y p e f o r MSBR p r o c e s s i n g systems. A s u f f i c i e n t r a n g e of flow rates, d i s t r i b u t i o n c o e f f i c i e n t s , e t c . , w i l l b e used t o a l l o w t e s t i n g of a general design relation.

3.7.5.2

Subtask 2.4.1.2 Hydrodynamics and mass t r a n s f e r i n s t i r r e d interface contactors

Development of c o r r e l a t i o n s f o r p r e d i c t i n g mass t r a n s f e r rates and d i s p e r s i o n of phases in s t i r r e d i n t e r f a c e c o n t a c t o r s of t h e L e w i s t y p e w i l l be continued. Experiments w i t h aqueous-mercury systems w i l l be conducted t o measure mass t r a n s f e r c o e f f i c i e n t s i n metal and aqueous phases. The e f f e c t of p h y s i c a l p r o p e r t y v a r i a t i o n s will b e i n v e s t i g a t e d . Improved methods f o r p r e d i c t i n g t h e c o n d i t i o n s under which t h e phases are d i s p e r s e d will b e developed. Mechanically a g i t a t e d c s n t a c t o r s i n which t h e phases are d i s p e r s e d w i l l b e developed f o r u s e w i t h L i C 1 - B I c o n t a c t o r s where bismuth entrainment i n t h e sale w i l l n o t b e a problem.

3.7.6

Task 2.4.2 Engineering s t u d i e s of h y d r o f l u o r i n a t i o n and h y d r o c h l o r i n a t l o n i n s a l t - b i s m u t h systems

The o b j e c t i v e of t h i s t a s k i s t o p r o v i d e t h e t h r e e phase (two-liquid phases and a g a s phase) c o n t a c t o r s which w i l l b e r e q u i r e d f o r o x i d i z i n g materials from bismuth streams t o r e t u r n them t o s a l t streams. Such o p e r a t i o n s w i l l , be r e q u i r e d f o r t h e HP-fluoride s a l t - b i s m u t h system i n t h e r e f e r e n c e p r o c e s s i n g f l o w s h e e t , and f o r t h e HC1-chloride s a l t - b i s n u t h system for f l o w s h e e t s under c o n s i d e r a t i o n f o r a c t i n i d e r e c y c l e . Following t h e salt-metal c o n t a c t o r s t u d i e s i n t h e Salt/Bismuth PlowThrough F a c i l i t y , t h i s f a c i l i t y w i l l be modified t o a l l o w t e s t i n g and development of t h e r e q u i r e d three-phase h y d r o f l u o r i n a t o r s . Design, i n s t a l l a t i o n , and o p e r a t i o n of an experimental h y d r o f l u o r i n a t o r f o r use w i t h t h e f l u o r i d e salt-bismuth system is planned. This system w i l l a l l o w €OK t h e measuring of rates of h y d r o f l u o r i n a t i o n of materials from t h e bismuth phase t o t h e f l u o r i d e s a l t phase and f o r o b t a i n i n g s u f f i c i e n t i n f o r m a t i o n f o r t h e subsequent d e s i g n of a h y d r o f l u o r i n a t o r f o r t h e Reductive E x t r a c t i o n P r o c e s s F a c i l i t y (Task 2 . 4 . 3 ) . T h i s hydrof l u o r i n a t o r w i l l u s e e i t h e r HF o r H2-HF m i x t u r e s . Experience gained i n t h e o p e r a t i o n of t h i s equipment w i l l permit t h e d e s i g n of a hydrochlorinator f o r use with chloride salts.

3.7.7

Task 2 . 4 . 3

(1) to conduct e n g i n e e r i n g experiments

t o measure mass t r a n s f e r d a t a i n c o n t a c t o r s of s u f f i c i e n t s i z e and w i t h s u f f i c i e n t accuracy t o b e used i n t h e d e s i g n of p r o c e s s i n g p l a n t compon e n t s and i n t h e subsequent d e s i g n of a s s o c i a t e d p o r t i o n s of t h e I n t e g r a t e d P r o c e s s T e s t F a c i l i t y , (2) t o advance t h e technology of m a n i p u l a t i n g

.... .!.... :.=

Reductive E x t r a c t i o n P r o c e s s F a c i l i t y

The o b j e c t i v e s of t h i s task are:

... ,s

3-46 n o l t e n salt and bismuth i n engineering equipment, and ( 3 ) t o advance t h e technology of f a b r i c a t i o n s f equipment s u i t a b l e f o r use i n an PllSBR grocessing system.

3.7.7.1

Subtask 2 . 4 . 3 . 3 .

D e f i n i t i o n of program and conceptual design

The reductive e m g t ~ a ~ t i opn ~ ~ ~ ef asc isl i t y will allow testing and development of equipment of a design s u i t a b l e for use i n a f u l l - s c a l e p r o t a c t i n ium rmaval process. The facility WLlH operate continuously and will be used t o develop multi-stage salt-bismuth c o n t a c t o r s , salt-bismuth hydrofluorinators, methods f o r reductant a d d i t i o n , and sther equipmemt i t e m s . An eweshental program will be deffned to accomplish these o b j e @ t i v e s . Conceptual desf of this f a c i l i t y will cons2st of a choice of t h e scale of the equipment i d e n t i f i c a t i o n and design of a u x i l i a r y equipnent (gas s u p p l i e s , excess reagent and waste disposal s y s t m s , instrumentation c a l i b r a t i o n s t a t i o n s , etc.), and prelfminary sketching and l a y o u t of equipment. This f a c i l i t y will be installed i n BLdg. 7503.

3.7.7.2

Subtask 2 . 4 . 3 . 2

Development work required for f i n a l design

3.7.7.3

Subtask 2 . 4 . 3 . 3

Final design

3.7.7.4

Subtask 2 . 4 . 3 . 4

Fabrication, i n s t a l l a t i o n , and t e s t i n g

Following i n s t a l l a t i o n of the % a c i l i t y t h e system will be leak checked, and the salt and bismuth w i l l be charged t o the system and w i l l be

3-47

P r k K ts i n i t i a l t e s t i n g Elnd Startup d e t a i l e d Check lists Will be prepared f o r t h e following o p e r a t i o n s : (1) startup and shutdown of RF supply systern; (2) s t a r t u p and shutdown a f t h e HI? d i s p o s a l system; (3) operation of

i n s t ~ u ~ ~ ~ e n t a t i( 4o )n ;salt and bismuth sampling; (5) salt and bismuth rec i r c u l a t i o n ; ( 6 ) reductant a d d i t i o n ; (7) h y d r o f l ~ o r i n ~ ~ ot o p er r a t i o n ; and (8) s a l t and bismuth d r a i n a g e .

..... m

The REPF will o p e r a t e c o n t i n u o u s l y and b e used to develop multistage salt-bismuth c o n t a ~ t o r s ,s a l t - b i s m u t h hydl-odluorinato~-s,and other required equipment items, Data w i l l be o b t a i n e d on m t e ~ i b a lof ~ cons t ~ ~ ~ t i oc n o r,r o s i o n , t h e rate of mass t r a n s f e r of uranium, Z~KCXXI~UIB, thorium, and lithium between s a l t and bismuth phases and other data r e q u i r e d for e v a l u a t i o n and design of p ~ o t a c t i n i ~removal m system. S u f f i c i e n t i n f o m a t i o n dl1 be obtained f o r t h e subsequent design of t h e a s s o c i a t e d p o r t i o n s of the Integrated Process Test F a c i l i t y (Task Group 2 . 9 ) .

3.7.8

Task 2.4.4

P r o t a c t i n i u m I s o l a t i o n Demonstration E q e r i m e w t

3.7.8.1

I 1

A l a r g e l a b 0 P a t o r y area capable of containing high l e v e l a l p h a a c t i v i t y i s ~ e q u i r e dfor the d e ~ ~ n s t ~ a t i o Cn e. l l 2 Zn Bldg. 3019 w i l l b e converted fmto two a l p h a b d ~ ~ ~ spaces ~ t o in q which MSBR f u e l p ~ o c e s s i n g e x p e r i ~ n itn~v o l v i n g a l p h a - e m i t t i n g materials, s p e c i f i c a l l y p r o t a c t i n i u m , w i l l be esnducted. T h i s conversion w i l l i n c l u d e e x t e n s i v e m o d i f i c a t i o n of the presmt f a e % l i t i e s inclmd5ng new f l o o r i n g , a new hot change KOOEI,

m o d i f i c a t i o n of the present v e n t i l a t i o n system, and new u t i l i t i e s .

3-48 Subtask 2.4.4.2

3.7.8.2

Program definition and conceptual desfgn

A review of the development program and identification of areas requiring

de~el~p~~tent will be completed. This will include locating and obtaining sufficient quantities of p r o t a c t h - h m f o r experimental purposes. U p ~ n determination of the amount of protactinium available, a flowsheet and preliminary layout of equipment will be completed. 3.7.8.3

Subtask 2 . 4 . 4 . 3

Development work required for final design

Prototypes sf the necessary experimental equipment will be designed, c~nstructed,and tested prior to the fhal design of t h e Protactinium Issfation Demonstration Experiment. Subtask 2.4.4.4

3.7.8.4

Final design

Final design, detailed flowsheet, and final equipment layout for the Protactinium Isolation Demonstration Experiment to be installed in Cell 2 of Bldg. 3819 will be completed. A detailed safety analysis will be prepared e

Subtask 2.4.4.5

3.7.8.5

Installation and initial t e s t i q

Fabrication of eqer5nental equipment will. be completed a d the equipment will be installed and tested before protactinium is added to the sy s tern 0

3.7.8.6

Subtask 2.4.4.6

Operation

Detailed check lists for all operations w i l l be prepared. This experiment ~ 2 1 1be operated continuously from late FY 1977 t o late FY 1978. These experiments will corroborate protactinium removal flowsheets which were developed solely from chemical laboratory data and extrapolations from engineering experiments in which no Pa was used, k....

3.7.8.7

Subtask 2.4.4.7 recPamation

Equipment disposal. and protactinium

me prOtacthhXIIl Will be K6KXWered %Pornthe

erhewtal equipment in a form which will be convenient for storage and reuse, probably as a re~ reduced form in Li-Bi a l l o y . The process will be designed f s this covery as the final step. The equipment will be decontaminated or removed and the facility will be decontaminated.

....

*:.l.*

3-49 ... .... ..... .:.:<*

3.8 ,.!.... Gd

.:....d.... l

ii,

6 3

TASK GROUP 2 . 5

-EARTH REPIBVAL

T h i s t a s k group covers a c t i v i t i e s n e c e s s a r y for t h e development of technology r e l a t e d t o t h e removal of r a r e - e a r t h f i s s i o n p r o d u c t s from MSBR f u e l carrier salt by select%vee x t r a c t i o n into l i q u i d bismuth cont a i n i n g r e d u e t a n t and t r a n s f e r t o molten LiCl. The i n i t i a l work i s concerned w i t h s t u d y of mass t r a n s f e r and hydrodynamics in salt-metal c o n t a c t o r s , and w i t h o p e r a t i o n of an e n g i n e e r i n g experintent t h a t u s e s s a l t and bismuth flow rates t h a t are about 1% of t h o s e r e q u i r e d f o r p r o c e s s i n g a 1000-MW(e) MSBR. The t a s k group sufminates i n t h e d e s i g n , c o n s t r u c t i o n and o p e r a t i o n of a f a c i l i t y f o r e n g i n e e r i n g development and t e s t i m g of components n e c e s s a r y for r a r e - e a r t h removal t h a t w i l l use s a l t and bismuth flow sates which are about 10%of t h o s e r e q u i r e d ( Be R). for a ~ O ~ O - ~W 3.8.1

Objective

The o b j e c t i v e of t h i s t a s k i s t o develop t h e technology r e q u i r e d f o r d e s i g n of equipment f o r s e p a r a t i n g the r a r e - e a r t h f i s s i o n p r o d u c t s from MSBR f u e l s a l t . ,:.... .:.a1

3.8.2

Schedule

The s c h e d u l e for e x e c u t i o n of Task Group 2 . 5 i s shown in T a b l e 3 . 8 . 2 .

3.8.3

,.;.a,

,?... ,$$

... .... ..... *a

Funding

Operating funds r e q u i r e d %or Task Group 2.5 are shown; in Table 3 . 8 . 3 . O b l i g a t i o n of c a p i t a l equipment funds i n t h e anaount of $280,008 w i l l be required during E T 1976 f o r c o n s t r u c t i o n of t h e Metal T r a n s f e r P r o c e s s Facility.

3.8.4

Facilities

The Metal T r a n s f e r P r o c e s s F a c i l i t y would be l o c a t e d i n t h e h i g h bay area of Bldg. 7503. T h i s f a c i l i t y w i l l be used f o r s t u d y and dmons t r a t i o n of t h e metal transfer p r o c e s s f o r r a r e - e a r t h removal w i t h flow rates which are about 10%of t h o s e r e q u i r e d i n a 1000-MW(e) MSBW. T h i s f a c i l i t y w i l l o p e r a t e c o n t i n u o u s l y from e a r l y FY 1977 to mid FY 1978. An e x i s t i n g f a c i l i t y , the S a l t / B i s m t h Flow-Through F a c i l i t y , l o c a t e d

... s+i

i n Bldg, 3592 i s c u r r e n t l y b e i n g used t o test mechanfealfy a g i t a t e d non-dispersing salt-bismuth e o n t a c t o r s .

--.

._.

Table 3.8.2.

Schedule fQH Task Gnxq 2.5 - ItaPe easth Pemsval

1976

2.5.1

Metal t?ransfer expesiwent PITE-3B

2.5.2

Salt-metal contactsr development 2.5.2 rn1 BydPadynatica 2.5.2.2 tfass taransfes 2.5.2.3 Removal of interfacial solids

2.5.3.2 2.5.3.3 2.5.3.4 2.5.3.5

Develapment far final testing Final design Fabricatfan, installatian, and testing Operation

-. ----

Table 3.8.3.

Operating

budget for Task Group 2.5 - Rare-earth (casts in 1008 dollars)

removal

Fiscal 1975 2.5.1

Metal

tramsfer

2.5.2

Salt-metal ssntaetor development 2.5.2.1 Hydrodynamics 2.5.2.2 Mass transfer 2.5.2.3 Removal of interfacial solids Subtotal

2.5.3

Total

experhen%

MTE-3B

Subtotal

2.5.3

operating

funds for Task Group 2.5

197%

19 78

188 180 180

150

1979

160

5 5 10 20

2.5.2

Metal Transfer Process Facility 2.5.3.1 Csnceptual design and experhental program 2.5.3.2 Development for final. design 2.5.3.3 Final desigm 2.5.3.4 Fabrication, installation, and testing 2.5.3.5 Operation

1976

year

5 1s 8 28 208

35 lb5 105 155 155

150 158

3-52

3.8.5

The study of mass t r a n s f e r rates of rare e a r t h s i n MTE-3B w i l l be conss t r a n s f e r rates w i l l be compared with l i t e r a t u r e and other correlati~nsbeing d e v d . ~ p e d . In a d d i t f o ~ ~the , long-tem s t a b i l i t y of t h e t r a n s f e r rates, t h e effect of solids a c e m u l a t i o n at t h e salt-metal i n t e r f a c e s on t r a n s f e r rates, and t h e e f f e c t of rare-earth concentrations on t r a n s f e r rates W a l l be i n v e s t i g a t e d . 3.8.6

Task 2.5.2

S a l t - m e t a l contactor development

The objective of t h i s task i s t o develop t h e technology necessary for designing equipment for contacting molten s a l t and molten bbsmuth in order t o carry o u t t h e transfer of rare earths from salt s t r e a s into bismuth streams. This t a s k i n t e r f a c e s with Task 2.4.1, Salt-Metal eontaetor Development. 3.8.6.1

Subtask 2.5.2.3

Removal of i n t e r f a c i a l s o l i d s

b..

3.8.7 I

Task 2.5.3

Metal Transfer Process F a c i l i t y

The o b j e c t i v e of t h i s t a s k is t o provide a f a c i l i t y f o r t e s t i n g and development of equipment of a design s u i t a b l e for use in a f u l l - s c a l e pKoc@ss for H e l l I O V a l Of %are earths from a MSBR fuel C a l p l p h r salt. Experiments w i l l be c a r r i e d out i n t h e f a c i l i t y t o develop m u l t i s t a g e salt-bismuth @ofatactors as well as o t h e r required equipment which will p ~ ~ v i dd aet a on the rate of removal of rare e a r t h s from the fuel carrier s a l t and evaluate t h e sujktabilfty of materials of construction and longtern r e l i a b i l i t y of system components. Provisions far maintenance of p ~ o c e s sequipment and removal of system components f o r modification, r e p a i r o r %Eastallation of equipment of alternate design will be included i n the design of the f a c i l i t y .

3-53 The facility will be located in the high bay area of Bldg. 7503 and will require the installation of purified KF, He, and A r supply systems. Initially the facility will be used for Metal Transfer Experiment NTE-4 with salt and metal flow rates 5 to 18% of those required for a lOOB-MW(e) MSBW. ... “a

3.8.7.1

Subtask 2.5.3.1 Definition of experimental program and conceptual design

....

y . m

The experimental program to be conducted during Metal Transfer Experiment MTE-4, which will be carried out in the Metal Transfer Process Facility, includes the following objectives:

1. demonstration of the removal of rare-earth fission products from MSBR fuel carrier salt and accumulation of these materials in a lithium-bismuth solution in equipment of a significant size; 2.

determination OS mass transfer coefficients between mechanically agitated salt and bismuth phases;

3. determination of the rate of removal of rare earths from the fluoride salt in multistage equipment ;

<*.... ,x

.:&

evaluation of potential materials of construction, graphite in particular;

testing of mechanical devices, such as pumps and agitators, that will be required in a processing plant; and

development of instrumentation for measurement and control of process variables such as salt-metal interface location, salt Plow rate, and salt or bismuth liquid level.

The proposed metal transfer process facility consists basically of the following systems: (E) a fluoride salt system with which molten fluoride salt containing rare-earth fluorides can be circulated at a controlled rate through a salt-metal contactor, (2) a salt-metal eontactor in which the rare earths are extracted from the fluoride salt and transferred to a stream of molten LiCI, (4) a LiCl system for cireulatimg the L i C l at a controlled rate between the salt-metal contactor and a Li-Bi stripper where the rare earths are removed from the LiCl and deposited in a b i s muth solution containing from 5 to 50 at. % Lf, ( 4 ) a salt-metal hydrofluorinator for removing oxide impurities from the salt and metal or for returning the rare earths from the Li-Bi solution to the fluoride salt after a run has been completed, and (5) drain and waste tanks for storing salt and bismuth that are removed from the system. The system will contain provisions for sampling the salt and bismuth phases in each vessel and for sampling the salt streams from the salt-metal contactor.

I I

i a

s l

3-54

The p r i n c i p a l equipment item are t h e f l u o r i d e s a l t surge tank, which has a volume of about 300 liters and will cons%st of a carbon steel liner in a stainless s t e e l vessel; a three-stage salt-metal c o n t a c t o r made of g r a p h i t e and enclosed i n a s t a i n l e s s steel containment vessel; ia S t X h l e S S Steel Vessel haviflg gKapkih2 OK caPbOn-Steel l h @ K fn Which %areearths Will be a@cmulatedin a l % ~ h ~ U ~ - b f S B l Us ot hh t Z h l l having a vohme of about 100 liters; and a hydKofluorlbnatoH t h a t has a volume of about 1563 liters and cowsists of a graphite crue3bPe enclosed i n a s t a i n l e s s steel vessel. Conceptual d e s i g n s f o r t h i s equipment will b e completed.

3.8.7.2

Subtask 2.5,3.2

Development w ~ r krequired far final design

Development work and f u r t h e r e v a l u a t i o n of existing process equipment r e q u i r e d bego,, the f i n a l design of t h e f a c i l i t y c a n be completed are:

1. 2.

Design c r i t e r i a from the s t a n d p o i n t of ease of fabrication and a c c e p t e d design technology for graphite vessels. Instrumentation for measurement and CCXI%KCI~ sf process variables

such as salt-metal i w t e ~ f a c el o c a t i o n s , salt f l o w rates, and s a l t and bismuth l i q u i d level.

3.8.7.3

I B

Subtask 2 . 5 . 3 . 3

Final design

3-55

3.8.7.4

Subtask 2 . 5 . 3 . 4

Fabrication, installation, and initial testha

Gas supply systems t o provide purified HF2 H z r o and Ar w i l l be installed in Bldg. 7583. An emergency electric power system consisting of a %OO-kVA, 48O-V, three-phase diesel-driven motor-generator will be used t o provide sufficient p ~ e tro maintain experiment operating conditions and prevent salt freezing in the event of loss of normal building power. After installation of- Metal Transfer Experiment MTE-4, the entire system w i l l be pressure tested to ensure that it is leak tight and then treated with hydrogen at 650'6 to ]reduce any oxides on the interior surfaces of the vessels. After the hydrogen treatment has been completed, the system will be flushed with argon and maintained under an argon atmosphere to prevent entry of air and m o i ~ t ~ e .

Prior to startup and initial operation of experbent MTE-4, datajiled operating procedures for all phases of operation will be written. These will include: (1) heatup of the HIT,-4 system, (2) bismuth purification and addition, (3) fuel carrier s a l t purification and addition, (4) Li-ltai preparation and addition, (5) LiCl purification and a d d i t i o n , (6) salt and bismuth sampling, (7) system shutdown (noma1 and emergency), (8) dPain%Plg Of Salts and bismUbh, and (9) additlbQn of earths to sys tern *

... .... :<.>a ....._

... .... ..... SS,

....

? & !

After the hydrogen treatment has been completed the system w i l l be flushed with argon, and salt and metal will be charged to the individual vessels. Fluoride salt that has previously been purified will be transferred as a l i q u i d into the fluoride salt storage tank. Bismuth that has previously been purified by treatment with hydrogen w i l l be charged in molten € o m to the salt-metal contactor. Initially, the Ei-Bi solution ~ O Kthe Li-Bi stripper may be prepared either in the ki-Bi stripper or in the salt-and-metal h ~ d ~ o f l ~ o ~ i n avessel t i ~ n to remove oxide impurities before it is transferred to the Li-Bi stripper. All of these operations have been carried out successfully on a smaller SCale in pK@V88%18 @XF3erflWnts. After the salt and metal phases have been charged to the systm, the E%Cl and fluoride salt pumps and flow meters will be tested and calibrated. To test the fluoride salt system, salt will be c~rcufatedfrom the fluoride salt storage vessel to the salt-metal contactor and back to t h e f%ansri.desalt storage vessel. The E X 1 pump and flow meter w i l l be tested and calibrated by circulating L i C l frm the Li-it31 stripper to the salt-metal contactor, and back to the Li-Bi str%pper. The system will then be ready to begin normal operation.

3-56

Operation of Metal Transfer Experiment l4TE-4 will begin with t h e a d d i t i o n of rare-earth f l u o r i d e s t o the f l u o r i d e storage tank. Both stable rare earths and t r a c e r quamtities of r a d i o a c t i v e rare e a r t h s w f l l be added. During operation, t h e rate of removal of rare e a r t h s from the f l u o ~ i d e S a l t and t h e COncemBtPatiOR of rare earths at p o i n t s tkrOUghout the system will be determined by p e r i o d i c a l l y taking samples of t h e various phases. This data w i l l permit evaluation of t h e e f f e c t i v e n e s s of salt-metal c o n t a c t o ~ sof various designs f o r t r a n s f e r r i n g rare e a r t h s between t h e s a l t and m e t a l phases. The length of an emperhent w i l l vary up t o about a week depending on t h e operating conditions and t h e rare earths used. After a run has been completed, t h e system will be prepared for the next run e i t h e r by adding a d d i t i o n a l rare e a r t h s t o t h e f l u o r i d e s a l t s t o r a g e tank and reductant (lfthium) t o the ki-Bi s t r i p p e r 0% the rare earths used t h e preVfouS lfUn Can be t%aIlSf@rred from the LI-Bi solution t o t h e fluoride salt by treating the two phases with HF in t h e salt-metal hydrofluorination v e s s e l .

Normally, the system w i l l be kept a t operating temperature between m n s d t h the m Q m 1 charge of s a l t and m e t a l i n t h e system. For r@pBacement of t h e salt-metal contactor, t h e salt and bismuth w i l l b e drained from t h e c o n t a ~ k o ri n t o a drafn tank. The salt-metal contactor and connecting lines will be ~ ~ o l etod room temperature f o r maintenance o r replacement. Freeze valves and argon purges w i l l be used t o prevent a i r and moisture from entering t h e reDK3hflag V e S S e l S When t h e I h e S to the COntaCtor" are opened. During a complete shut d o m , s a l t and m e t a l w i l l be drained from t h e salt-metal c o n t a c t o ~ ,t h e L i - B i s t r i p p e r , and t h e salt-and-metal hydrofluorinati~n vessel i n t o drain tanks before t h e s e vessels are cooled d m , since freezing sf s a l t o r bismuth i n t h e s e vessels could cau5e damage to the g r a p h i t e or molybdenum lfners. The salt will remain i n t h e f l u o r i d e s a l t storage vessel during a shutdown f o r maintenance.

3.9.1

Objective

3.9.2

Schedule

The schedule for this task group is sham in Tabla 3.9.2.

operating funds required f o r this t a s k roup are s h m fn Table 3 . 9 . 3 . Capital equipment funds in t h e mount o $25,880 w i l l be required FY 1977 for a computerized v o x t m e t e r t o allow [U"]/[U4+3 measurements.

3-57

Table 3.9.2.

Schedule f o r Task Group 2.6 - F u e l s a l t p u r i f i c a t i o n I

Fiscal y e a r

1975

2.6.1

Uranium v a l e n c e adjustment

2 6.2

Bismuth removal Removal of e n t r a i n e d bismuth 2.6.2.1 2.6.2.2 Removal of s o l u b l e bismuth

1977

1976

1978

. . . . a

Table 3 . 9 . 3 .

Operating budget f o r Task Group 2.6 - F u e l (costs i n 1600 d o l l a r s )

salt purification

F i s c a l year

1975

..;.d

2.6.1

Uranium v a l e n c e adjustment

2.6.2

Bismuth removal 2.6.2.1

W ~ R l S V d Of

2.6.2.2

bismuth Removal of s o l u b l e b ismu th

1976

I977

1978

entrained

2.6.2 funds f o r Task Group 2.6

1979

3-58

3 9 4 e

Facilities

The Reductive E x t r a c t i o n B E - Q ~ ~ SFS a c i l i t y (Task 2 . 4 . 3 ) and t h e Metal T r a n s f e r Process F a c i l i t y (Task 2.5.3) w i l l b e used t o test methods f o r bismuth removal. The Plusr%n%t%ara-We6onstit~tion EngPneering Facility (Tasks 2.2.7 and 2 . 3 . 3 ) w i l l be used to test methods for uranium v a l e n c e adjus tment *

Task 2.6.1

3.9.5

Uranium v a l e n c e adjustment

o b j e c t of t h i s task is to develop the technology for continuously c o n t r o l l i n g the [ u ” ~ / [ u ~ + Iratio i n the f u e l s a l t stream returning t o the r e a c t o r . A method by which t h e &U4*Qa/[U3*’3 ratio can b e a d j u s t e d , such as e l e c t ~ ~ l y t riecd u c t i o n of [U“] w i l l b e developed. Equipment w i l l be i n s t a l l e d 2n fzhe Flu~r~~ation-Reesnstitutisn Engineering F a c i l i t y c o n t r o l of uranium v a l e n c e i n t h e s a l t t o s t u d y c ~ n t i ~ ~ u oclosed-loop us from t h e re~onstftutions t e p of this f a c i l i t y . ..... .

&. , .

3.9.6

Task 2.6.2

Bismuth removal

The object of t h i s task i s t o develop t h e technology for moving b o t h entlrained and dissolved bismuth from f u e l s a l t b e f o r e i t e n t e r s the r e a c t o r from t h e p r o c e s s i n g p l a n t . Experiments for demonstrating eontinusus bismuth removal will be c a r r i e d out i n t h e Netal T r a n s f e r P r o c e s s n Facility. Sampling techF a c i l i t y , and t h e Reductive E x t ~ a ~ t i oProcess niques w i l l be. developed for u s e w i t h low bismuth c o n c e n t r a t i o n s i n f l u o r i d e s a l t s . ~ e s t sto s t u d y the effectiveness of n i c k e l wool beas for removing e n t r a i n e d bismuth w i l l be p e r f o m e d , Chemical s t u d i e s t o i d e n t i f y the disaslved bismuth s p e c i e s w i l l be c a r r i e d o u t and methsds f o r remving these s p e c i e s d1.1be aeveaoped.

3.10

TASK GROUP 2.7

3.10.1

Obiective

ACTINIDE-FISSION PRODUCT SEPARATION AND

The s b j e c t i v e of t h i s t a s k group i s t o develop a f l o w s h e e t for f u e l processing which will a%%ow t h e transdraniurn a c t i n i d e s to be separated from t h e fission p r o d u ~ t sand r e t u r n e d t o the K ~ ~ C ~ f o O r P transmutatton t o less u n d e s i r a b l e i s o t o p e s .

3 18 2 0

Schedule

The schedule f o r this task group is s h o w in Table 3.10.2.

3-59

Schedule f o r Task Group 2.7 - Actinide-fission product separation and actinide recycle

Table 3.10.2.

2.7 .I clamistry studies 2.7.1.1 Chemistry of zireoniua chlorides 2.7.2 I

PBowsheet development 2.7.2.1 B e a t balances 2.7.2.2 Mass balances 2 7 2.3 Parametric studies 2 7 2 4 Waste characterization a e

<..*

2.7.3

Identification of r e q u i r e d development

Table 3.18.3. O p e ~ a t i n gbudget f o r Task Group 2.7 Actinfde-fission product separation and actinide r e c y d e (costs in 1000 dollars)

F i s c a l year 1975

2.7.2

Plowsheet development 2.7.2.1 Heat balances 2.7.2.2 Mass bsilances 2.7.2.3 Parametric s t u d i e s 2 . 7 . 2 . 4 Waste characterization Subtotal 2 e 7 2

2.7.4

Identification Of required development

lo 5

5 __.

T o t a l sperathg funds for Task Group 2.7 .:.&

1976

3-60

3.10 3 e

Funding

The operating budget f o r t h i s t a s k group is shorn in Table 3.10.3. No c a p i t a l equipment funds will be required.

3.10.4

Facilities

p".

This work w i l l r e q u i r e only t h e use of 0R.PZ computing f a c i l i t i e s and general chemical laboratory f a c i l i t i e s .

The primary o b j e c t i v e of t h i s t a s k is t o determine the oxidation state of z i r c ~ ~~h b l o~ r i d~ edissolved ~ i n molten ki@l when t h e c h l o r i d e m e l t i s i n equilibrium with Lf-BB a l l a y s o r in equilibrium with HCl-M2 mixt u r e s . I n i t i a l l y , t h e oxidation state w i l l be determined as a function of t h e l i t h i u m concentration i n t h e a l l o y . A special e f f o r t w i l l be t o determine conditions under which gaseous zirconium c h l o r i d e i s present at significant partial pressures above the Lie1 solution. Some effort will be devoted t o determining a c t i v i t y c o e f f i c i e n t s f o r ZrCB4 Qor ZrClg) in molten E i C l solution. Work i n t h i s t a s k group is required f o r determining t h e behavior of zirconium i n actinide-recycle flowsheets under consideration.

3.10.6 3.lQ.6.l

Task 2 . 7 . 2

Flowsheet a n a l y s i s

Subtask 2.7.2.l

H e a t balances

An e x i s t i n g general computer code wfll be used t o c a l c u l a t e t h e mount of decay heat release for each operation i n t h e processing p l a n t . This is necessary t o determine t h e h e a t transfer area required in each piece of equipment. I n some cases, t h e allowable heat release rate will l i m i t the f i s s i o n product concentrations because of heat removal coneiderat i o n s . Decay heat generation rates w i l l be obtained from concentration d a t a determined i n mass balance c a l c u l a t i o n s .

3.10.6.2

Subtask 2.7.2.2

Mass balances

For the proposed flowsheet mass balance c a l c u l a t i o n s w i l l be made f o r each f i s s i o n product nuclide and f o r a l l transuranium isotopes. The computer codes mentioned i n the previous s e c t i o n w i l l also be used here. The mass balance calculations w i l l be coupled with a c a l c u l a t i o n f o r t h e reference r e a c t o r design i n order t h a t t h e e f f e c t of c a l c u l a t e d removal t i m e s and t h e e f f e c t of r e c y c l e of transuranium isotopes ow t h e r e a c t o r performance can be determined. A l l c a l c u l a t i o n s w i l l be continuably updated as new process d a t a ( e q u i l i b r i a , mss t r a n s f e r , etc.) become aVailable.

L..

..& ....

3-61

3.10.6.3

Subtask 2.7.2.3

Parametric s t u d i e s

The computer code which c a l c u l a t e s m a s s b a l a n c e s , h e a t g e n e r a t i o n rates, and waste p r o d u c t i o n rates w i l l be used t o do p a r a m e t r i c s t u d i e s i n o r d e r t h a t m o d i f i c a t i o n s of t h e f l o w s h e e t w i l l r e f l e c t a n o p t i m i z a t i o n of t h e e f f e c t caused by each c h a r a c t e r i s t i c which i s s t u d i e d . Parameters t o be v a r i e d i n c l u d e r e d u c t a n t c o n c e n t r a t i o n s , c i r c u l a t i o n rates, and m o d i f i c a t i o n s of t h e f l o w s h e e t . 3.10.6.4 ,&&,

Subtask 2.7.2.4

Waste c h a r a c t e r i z a t i o n

The material b a l a n c e c a l c u l a t i o n s u s i n g t h e p r e v i o u s l y mentioned comp u t e r codes w i l l b e used t o d e s c r i b e volumes and c o n a p o s i t i ~ n sof waste streams a s s o c i a t e d w i t h each proposed f l o w s h e e t . Waste d i s p ~ s a lproblems a s s o c i a t e d w i t h each f l o w s h e e t w i l l b e a s s e s s e d from t h e s e c a l c u l a t i o n s . For each waste stream, c a l c u l a t i o n s u s i n g t h e computer code ORIGEN w i l l b e made t o determine t h e a c t i v i t y and waste hazard as a f u n c t i o n of t h e and t o compare waste h a z a r d s of MSBR's w i t h waste h a z a r d s of o t h e r reactors.

3.10.9

Task 2.7.3

I d e n t i f i c a t i o n of r e q u i r e d development

A n a l y s i s of f l o w s h e e t s g e n e r a t e d i n t h i s t a s k w i l l allow i d e n t i f i c a t i o n of areas in which development work must b e c a r r i e d o u t i n o r d e r t o assess t h e d e s i r a b i l i t y and f e a s i b i l i t y of t h e r e s u l t a n t f l o w s h e e t s . A r e p o r t summarizing t h e r e s u l t s of t h i s a n a l y s i s and i n d i c a t i n g t h e r e q u i r e d development work w i l l be i s s u e d . 3.11

TASK GROUP 2.8

MSBR PROCESSING ENGINEERING LABORATORY

DESIGN AND CONSTRUCTI8N 3.11.1

Objective

The o b j e c t i v e of t h i s t a s k group is t o p r o v i d e s p a c e f o r e n g i n e e r i n g and chemical development a c t i v i t i e s a s s o c i a t e d w i t h t h e development of t h e technology f o r p r o c e s s i n g t h e f u e l from m o l t e n - s a l t b r e e d e r r e a c t o r s .

....

..... .=

The a v a i l a b l e work s p a c e f o r chemical and e n g i n e e r i n g development of MSBR f u e l r e p r o c e s s i n g c o n s i s t s of one small a l p h a l a b o r a t o r y i n BPdg. 3019; two s t a n d a r d chemical l a b o r a t o r i e s i n Bldg. 4500; B1dg. 3592, which h a s two equipment areas, each a b o u t 15 x 15 x 8 f t h i g h ; Bldg. 3541, equipped w i t h t h r e e s t a n d a r d l a b o r a t o r y hoods and two walk-in hoods; and Bldg. 4505, where two 6 x 8 x 26-ft-high c e l l s p a c e s have been converted t o p e r m i t experiments w i t h b e r y l l i u m salts; and a p o r t i o n of t h e high-bay area i n Bldg. 7503 (MSRE b u i l d i n g ) . These work areas have been o b t a i n e d by modifying e x i s t i n g f a c i l i t i e s . The f a c i l i t i e s permit work w i t h a l p h a materials i n Bldg. 3019 and b e r y l l i u m o n l y i n

3-62 a l l o t h e r areas. Change room e n t r a n c e s and o t h e r provisions are m a r g i n a l f o r all areas except Bldg. 35411 and Bldg. ?503. The e x i s t i n g e only f o r l i m i t e d a l p h a l a b o r a t o r y work, s m a l l f a c i l i t i e s a ~ adequate bench-scale e n g i n e e r i n g t e s t s of i n d i v i d u a l system components, and tests of 1 / 2 - s c a l e i n d i v i d u a l p r o c e s s equipment u n i t s . None of t h e engineeri n g f a c i l i t i e s w i l l permit p r o o f - t e s t i n g w i t h a l p h a - a c t i v e materials OK demonstration O f a complete p r o c e s s i n g p l a n t system, even on a very s m a l l scale. F u l l - s c a l e t e s t i n g of t h e complete p r o c e s s i n g system w i t h molten salt and bismuth, a l p h a materials, and perhaps low-level b e t a 8 r a d i o a c t i v e tracers w i l l b e r e q u i r e d tu demonstrate p r o c e s s performance. The e x i s t i n g f a c i l i t i e s a r e crowded, are i n e f f i c i e n t because of t h e assignment of persontaeE t o w i d e l y s e p a r a t e d f a c i l i t i e s , and are csmplletely inadequate f o r t h e planned development program. No o t h e r f a c i l i t i e s e x i s t a t the Laboratory t h a t could meet t h e s p e c i f i c and Unique r@quik-eUEnts f B % engineering deVelQpIWnt O f HSBa prOCeSSiIlg. Engineering-scale experiments planned f o r the f a c i l i t y w i l l range in complexity from simple t e s t 1oops f o r pump and v a l v e development for molten salt o r bismuth systems to a f u l l - s c a l e i n t e g r a t e d p r o c e s s i n g equipnent i n s t a l l a t i o n f o r o p e r a t i o n w i t h low-level b e t a - g a m tracers and a l p h a materials. 3.11.2

w...

. .

bx.:.>

Schedule

The s c h e d u l e f o r Task Group 2.8, HSBR P r o c e s s i n g Engineering Laboratory Design and C o n s t r u c t i o n , i s g i v e n i n Table 3.11b.2.

3.lb.3

Funding

The operating budget f o r Task Group 2.8 is shown i n Table 3.11.3. 'This t a s k w i l l r e q u i r e GPP funds ~f about $12,000,00Q9t o b e a u t h o r i z e d in m l977. 3.11.4 This p r o j e c t w i l l . c o n s i s t of a new b u i l d i n g which will b e capable of c o n t a i n i n g l a b o r a t o r y and l a r g e - s c a l e e n g i n e e r i n g experiments wPth b e r y l l i u m and thorium co s u d s and a l p h a - e m i t t i n g materials. The b u i l d i n g w l % P b e a t h r e e - s t o r y c o n c r e t e and masonry b u i l d i n g with a m e t a l high-bay area. Overall dimensions will b 1 2 5 P t by 152 f t by 4% f t high. me high-bay area w i l l b e 45 f t h i An 18 f t by 3 2 f t by 15 ft t r u c k a i r l o c k w i l l b e provided i n t h e high-bay area. The b u i l d i n g , p l u s a i r l o c k , w i l l have a ~ K O S Sf l o o r area of 33,000 ft2 and a g r o s s velame of about ~ Q O , C B O Og t 3 * ~ o r t i s n sof t h e b u i l d i n g will. b e sealed and o p e r a t e d a t a n e g a t i v e p r e s s u r e of 8 . 3 in. B20 t o p r o v i d e s u i t a b l e csntainment of h a z a r d l ~ u smaterials. e

Task 2.8.1 c o n s i s t s of e s t a b l i s h i n g (1) the c r i t e r i a f o r t h e building; (2) p r e p a r i n g a s a f e t y a n a l y s i s and a n environmental s t a t e m e n t ; (3) dev e l o p i n g p r e l i m i n a r y s i t e p r e p a r a t f o n p l a n s , f l o o ~p l a n s , a r c h i t e c t u r a l

h..

Table 3.11.2.

Schedule for Task Group 2.8 - MSBR Pracessing Laboratory design and construction Fiscal

2.8.1

Concxptual

2.8.2

Title

I design

2.8.3

Title

II design

2.8.4

Construction

2.8.5

-1

._-

design

Acceptance of facility (system tests)

-_--

year

Engineering

-e--s..%.-

----

Table 3.11.3. Operating budget fob Task Gsaup 2.8 - M§RR Processing Engineering kabarato-ry design and construction (costs in BQQQdollars) Fiscal. year

design

1975

1976

1977

2.8.1

Conceptual

2.8.2

Title

I design

187

2.8.3

Title

TI design

2.8.4

CQnStKUCtiQIl

2.8.5

Acceptance of facility

Total

operating

casts far Task Group 2.8

250

1978

1979

198Q

150

158

295

150

40 190

225

1981

3-65

and s t r u c t u r a l p l a n s , u t i l i t y p l a n s , and waste d i s p o s a l p l a n s ; ( 4 ) prep a ~ i n ga c o s t estimate € O K t h e p r o j e c t ; and (5) p r e p a r i n g and s u b m i t t i n g a long € o m c o n s t r u c t i o n p r o j e c t d a t a s h e e t f o r EY 1977 p r o j e c t authorization.

.... < .A

3.11.5

Task 2 . 8 . 2

T i t l e I design

T i t l e 1 design f o r t h e building w i l l begin a f t e r p r o j e c t a u t h o r i z a t i o n 1979. This work r e p r e s e n t s t h e f i r s t d e f h i t i v e d e s i g n WOK^ and in must be completed b e f o r e c o n s t r u c t i o n s t a r t s i n o r d e r t o v e r i f y t h e c o n c e p t u a l d e s i g n , t h e scope of t h e p r o j e c t , and t h e estimate of p r o j e c t c o s t . Operating fund requ5rements d u r i n g T i t l e 1 d e s i g n cover 5 $0 6 p e r s o n n e l , i n c l u d i n g t h e program and p r o j e c t e n g i n e e r s ; design work n o t covered by c a p i t a l funds; advance procurement, e s t i m a t i n g , and l f a s o n between t h e program and p r o j e c t a c t i v i t i e s .

3.11.6 .... rn

Task 2 . 8 . 3

T i t l e I1 d e s i g n

Title II d e s i g n w i l l s t a r t immediately a f t e r t h e T i t l e I: design has been t e f i ~ e st h e c o n s t r u c t i o n a c t 5 v i t i e s to b e undercompleted. T h i s e f f o ~ d taken and some c o n s t r u c t i o n , such as s i t e p r e p a r a t i o n , w i l l begin b e f o r e completion of T i t l e I1 d e s i g n . Operating f m d s are r e q u i r e d d u r i n g T i t l e I1 d e s i g n f o r purposes similar t o t h o s e d i s c u s s e d above f o r Title I design. 3.11.9

Task 2.8.4

Construction

C o n s t r u c t i o n w i l l b e g i n in mid FY 1978 and continue through FY 1980. This p e r i o d i n c l u d e s t h e t i m e r e q u i r e d f o r a c c e p t a n c e tests. Operating funds are r e q u i r e d f o r s u p p o r t of t h e p r o j e c t and program e n g i n e e r s . .... \ .:.z

3.11.8

Task 2.8.5

Acceptance of f a c i l i t y

.... ,:*,

All equipment i n t h e f a c i l i t y must b e t e s t e d b e f o r e t h e f a c i l i t y w i l l b e a c c e p t e d . These s y s t e m t e s t s w i l l t a k e p l a c e d u r i n g t h e l a s t t h r e e

months of c o n s t r u c t i o n .

3.12

TASK GROW 2 . 9

3.12.1

Obj e c t i v e

INTEGRATED PROCESS TEST FACILITY

The o b j e c t i v e of t h i s t a s k group is t o p r o v i d e a f a c i l i t y f o r t h e demons t r a t i o n of p r o c e s s e s and equipment f o r f u e l p r o c e s s i n g a t t h e p i l o t p l a n t level i n a n o n r a d i o a c t i v e system. T h i s f a c i l i t y i s needed (1) t o demonstrate t h e s a f e t y and performance r e l i a b i l i t y of p r o c e s s i n g systems, (2) t o p r o v i d e i n f o r m a t i o n f o r development of maintenance methods, and

3-66

The schedule f o r t h i s task group i s shown in Table 3.12.2.

3 12 3 e

Funding

The o p e r a t i n g budget f o r this task group i s s h o w in Table 3.12.3.1. Authorization of capital f u n d s i n the m o u n t sf $7,6QO,QOB w i l l b e required during FY 1978. C a p i t a l equipment fund Pequir@ments are shorn in Table 3 . 1 2 . 3 . 2 .

3.12.4

Facilities

The I n t e g r a t e d Process Test F a c i l i t y will consist sf the equipment necesSaKy for t h e S i I R U l t a t a e O U S O p e K a t i O l a Sf all parts of a pro@eSSklg SyStelll for s t u d y and d QnStraefOn Of COHnt~EaUOUS prOCeSSfIlg Of TiIQlteH1-Sd.t breeder reactor fuel s a l t on a scale t h a t is 25% to 75% of t h a t r e q u i r e d f o r a 1000-WCe) MSBR. Operation of the system will be c a r r i e d o u t u s i n g t r a c e r - - l e ~ e l a c t i v i t y s u i t a b l e f o r d e t e m i n i n g the b e h a v i o r of key a e t i ~ be tested i n c l u d e n i d e and fission p r o d u e t elements. The o p e r a t i ~ nto f l u o r i n a t i o n of fuel s a l t for removal sf uranium, r e d u c t i v e e x t r a c t i o n f o r remaspal sf p r o t a c t i n i u m , rare-earth removal by the metal transfer p r o c e s s , and s e c o n s t i t u t i s n sf MSBW f u e l spait from UP6 recovered i n the f l u o r i n a t i o n o p e r a t i o n and t h e processed fuel carrier s a l t . The t o t a l e s t i m a t e d c o s t f o r t h e I n t e g r a t e d B K O C ~ S STest Facility is $7 million and authorization is r e q u i r e d d u r i n g 1978.

3.12.5

Task 2.9.1

D e f i n i t i o n of experimental program and

The e x p e r h e n t a l program will b e d e f i n e d a d the f a c i l i t y w i l l be des i g n e d a c c o r d i n g l y . Preliminary d e s i g n of t h i s f a c i l i t y will consist of a c h o i c e of t h e scale sf t h e equipment, i d e n t i f i c a t i o n of a u x i l i a r y equipment (gas supplies, excess r e a g e n t and waste dispersal systems, Bsstrumentation c a l f b r a t i o n s t a t i o n s , e t e . ) location of equipment, and preliminary sketchin and layout of equipment. The areas whe f u r t h e r development w i l l be required for completion of final desi will be i d e n t i f i e d . Experimental programs to carry out t h i s develsgment will b e planned.

Table

3.12.2.

Schedule

for

Task Gscmp 2.9 - Integratad

Process

Teat Faeflity

1986 2.9.1

Pren.3nfwa~ experimtal

design arid psogram

2.9.2

Bevelspnent aes ign

for

2.9.3

Conceptual

design

2.9.4

Title

I des?sfgn

2.9.5

Title

2.9.6

Equipm@nt fabr%eation

2.9.7

Equfpkmt

hstallatisn

2.9.8

Initial ogeratsr

testfng and training

2.9.9

operation

final

dgsign

Table

3.X2.3.1.

QpeKatimg

1975 2.9 .P 2.9.2

PrelfdIlrrKy eqarimntal

aeaigF.l ad pKQg%

Developamt Beefgm

fQK final

btadgat

I.976

fOK Task Grsup 2,9 - IngeglPated (costs im 1QOQ doflars)

1977

1978

170

CQmceptmad. desigm

2.9.4

Title

I dasiJp

f5Q

2.9.5

Title

2.9.6

Equipant

fabrication

2.9.7

Equipmat

inataflation

2.9.8

T.rmitial oparatar

testing and traimhg

desi@~

QpePatdQn

Total operating eraup 2.9

Fiscal

year

I.980

19 81

fog T'aak

1983

1984

1985

2167 ----

2824

2700

2458

2824

2700

158 208

2QQ 75

3QQ 291

~~-~~--"-cssts

1982

2.9.3

2.9.9

31979

PPQCt388 T@et Facility

165

190

240

350

275

591

291

1986

Table

3.12.3.2.

Capital equipment fund Process Test Facility

requirements (costs in

for Task Group 1QQQ dollars)

2.9

Fiscal. 1980 2.9.7

2.9.9

Total

Computer control

for

data

Integrated

year

1982

1983

1984

1985

200 _I 200

300 300

400 400

300 300

and process 400

Miscellaneous instrumentation capital

processing

1981

equipment

funds

and

for

Task

Group

3.12

400

1986

3-70

3.12.6

Task 2.9.2

Development work required for design

Development work whish will be required includes (1) developmnt sf special instmmentatisw, and (2) d e v e l o p m a t of f i l t l - a t i ~ ntechniques for particulate removal. Other areas requjiring development w i l l be defined during p r e l i d n a r y design.

Title 1 design $OK the facility will begin after a u t h o r i z a t i o n in EY 1978. This Work Keplresents t h e first definitlkve design Work BH1d must be completed before construction starts in order to v e r i f y the concept u a l design, the scope of the project, and the estimate of p r o j e c t c o s t . a p e r a t i l l g fund reqUireKWIltS during T i t l e 1 d e s i g n COVeK 5 t Q 6 PerSonnd including the program and project engineers, design work n o t covered by capital funds, advance procurerrrent, estimating and liassn between the progrm a d project activities.

3.12.9

Task 2.9.5

Title 11 design

T i t l e I1 design will start i e d i a t e l y after the Title I design has been completed. This ~ % % Q K $defines fabrication and construction a c t i v i t i e s to be undertaken and some equipment fabrication caw begin before CQIPpietion ~ i t i eEI aesi ZP. @eKatkg f U d S 58re KeqUired d u r i n g T i t l e 1 design for purposes similar to those dFscussed above for Title 1 design.

3.12.EO

Task 2 . 9 . 6

Equipment fabrication

Some equipment fabrication will begin soon after Title I1 design begins. Operating funds are r e q u i r e d to support four personnel fog p r o j e c t engineering and lfason between design and fabrication a c t f v i t i e s .

EquQment installation will begin as i n d i v i d u a l equipment itma become available. Operating funds aupportfng s f x personnel w i l l be required far biason bemeera fabrication and installation a c t i v i t % e s .

<..... -

3-73.

3.12.12 .... ..la ...,

.... .... ..:.:.:e .-

.... .... .ss

....

,322

&&q

,.... ..... :.:..

.... .... *E#

.... .*. ...

.... .m,

,*z

.... ......... 1

Task 2.9.8

I n i t i a l testing and operator training

Acceptance tests will include leak checks and testing of all pumps, electrical equipment. S a l t and bismuth w i l l be charged to t h e system and w i l l be circulated at flow rates up to the d e s i g n limits. This period will also be used for t ~ a i n i n goperating ~ ~ K S O I X I ~ ~ .

~ O ~ Q K S and ,

3-92

M. E. WhatEey, %. E. McNeese, W, L. Carter, L. M. F e r r i s , and E. L. N ~ c ~ o ~ s s ~NZLGZ. s, AppZ. Tech. 8: 170-178 (1970).

~.~

..... . .

10.

E. E. McMeese, Engineering Development Stkid&% for Molten-Salt Breeder Reactor Pmcessing go. 6 , 0m%-?3%-3141(~eeember1971)

K R &sgPm SerrPiannu. m g r . Rep. Aug. 32, 2970, o m - 4 6 2 2 .

3-73

17.

J. S. Watson and L. E. McNeese, "Axial Dispersion in Packed Columns During Countercurrent Flow, Liquids of High Density Difference," dnd. Eng. Chem. Process Des. DeveZop. 11: 120-21 (1972).

18.

J. S. Watson and H. D. Cochran, "A Simple Method for Estimating the Effect of Axial Backmixing on Countercurrent Column Performance," Ind. fig. Chern. P~ocessDes. Develop. 18: 83-85 (19?l) e

2%.

Cherntcal Technology Diu. Annu. B o g . Rep. Mmbh 31, 9973, o m - 4 8 8 3 , p . 25.

22.

W. H. Carr, "Volatility Processing of the AKE Fuel," fiem. E n p . P m p . Syrnp. S e r i e s . 56 (1960) p a 57.

23.

Chemicat Technology Diu. Annu. PPQLJP.Rep. M a y 31, 2 9 6 4 , O m - 3 6 2 7 , pp. 29-35.

24.

W. H. ~ a r r ,et a%., 2iPoZteaz S a l t VoZatXlity P i l o t Plant: Recovery of Eszriehed Uyaanitgn fyaom AZdnum-Clad FueZ Elements , OWL-4574 April 1971.

25.

R. B. Lindauer, Bocessing of the MSRE FZugh m d Fuel S a l t s , OIWL-PIM-2578 (August 1969).

1FUEL-BRE)CESSING MATERIALS DEVELOPMENT

..... ,*

... ..... , :B

... ..... c:w

... .fLli

4 3. I e

Obj ective

The objecttves of the f u e l - p r o c e s s i n g mterials development program are to i d e n t i f y materials c a p a b l e of s a t i s f a c t o r i l y contatning t h e f l u i d s p ~ e s e n ti n an MSBR f u e l p r o c e s s i n g system, and t o develop t h e materials technology n e c e s s a r y f o r c o n s t r u c t i n g a p r o c e s s i n g system. It should b e c l e a r l y recognized t h a t a s a t i s f a c t o r y r e s o l u t i o n of materials problems will probably i n v o l v e the use of several materials as d i s c u s s e d below.

4.1.2

Scope

The scope of this program consists i n i d e n t i f y i n g materials which are compatible w i t h t h e f l u i d s p r e s e n t i n a f u e l p r o ~ e s ~ i n Bfec o d u c t h g f a b r i c a t i o n a d j o i n i n g s t u d i e s to p r o v i d e iflfQrL€E&tiO8 q u i r e d for c o n s t r ~ c t i o nof p r o c e s s i n g systems. 4.1.2.1

Task Group 3.1 materials

I d e n t i f i c a t i o n of C O ~ I - O S ~ Qresistant ~

Csmpatibi1Fty t e s t s will be conducted with NSBW fuel s a l t , Bi-Li-'I% s o l u t i o n s , and Li61 mder conditions which simulate f u e l p r o c e s s i n g systems i n o r d e r t o i d e n t i f y s a t i s f a c t o r y containment materials for t h e various process s t e p s .

4.1.2.2

Task Group 3.2 techniques

Development of f a b r i c a t i o n and j o i n i n g

Based on i n f o m a t i o n o b t a i n e d i n Task Group 3 . 1 , materials will b e s e l e c t e d f o r f a b r i c a t i o n of MSBW fuel p ~ ~ ~ e s s experiments ing and systems. F a b r i c a t i o n and j o i n i n g s t u d i e s w i l l b e conducted as ~ e q u i r e din o r d e r to (1) develop fabrication procedures (2) determine optimum fabrication v a r i a b l e s , and (3) develop a b a s i s for improving p r e s e n t procedures.

1 . 3

4-1

4-2 9

4.1.2.3

Task G ~ o u p3 . 3 and system

Construction of fuel processing experiments

Once the general details for a fuel processing experiment or system have been fixed, materials and fabrication procedures for construction of the associated equipment w i l l be selected and qualified. In some casesz p r a t o typic construction of components using data obtained in Task Group 3 . 2 W i l l

4.2.1

be reqUiKed.

Schedule and key program milestones

The schedule for work on fuel processing materials development is shown in Table 4.2.1.1. The key program milestsnes associated with the development of fuel processing materials are listed in Table 4.2.1.2 and occur at t h e times indicated in Table 4.2.1-1-

Operating fund requirements f o r W O P ~on fuel p~oeessingmaterials development are shown in Table 4.2.2.1, and capital equipment fund requirements are shown in Table 4 . 2 . 2 . 2 . 4.3

MATERIAL REQUI

NTS, BACKGROUND, wE%B STATUS OF DEVELOPMENT

4.3-1 Materials requirements

In t h e reference f u e l processing flowsheet: a IAUI&~K of environments are present: salt and gaseous mixtures of FZ and U F ~at 508 to 550°C.

1. &Iten 2.

Molten salt and bismuth containing lithium and thorium at 550 to 6maC

Bismuth containing 5 to 58 at. x Ei and L661 at 558 to 650eC*

m-H2 mixtures and ~goltenfluorides at 550 to 6%O°C.

.. . ..... vi..;. Yl.

4-3 p o r t i o n s of t h e system. A fundamental requirement of t h e materials s e l e c t e d i s f a b r i c a b i l i t y , for u l t i m a t e l y t h e materials must be used i n t h e construction of commercial processing p l a n t s . A v a i l a b i l i t y and c o s t are a l s o important f a c t o r s t h a t must be considered. ..&

....., m

..... .>z

4.3.2

Background

Nickel o r a nickel-base a l l o y , which i n some cases mst be protected from corrosion by a l a y e r of frozen s a l t , can be used f o r construction of flusr i n a t o r s f o r removal of uranium from molten f l u o r i d e ndxtures, and f a r those portions of a p l a n t t h a t w i l l contain F2, UFg, and HP. The c h e d c a l corrosion of n i c k e l and nickel-base a l l o y s during f l u o r i n a t i o n operation^ has been evaluated previously a t ORNIL. Much s f t h i s information has evolved from f u e l recovery operations conducted with i r r a d i a t e d m e t a l l i c r e a c t o r f u e l elements using molten f l u o r i d e d x t u r e s i n which UF4 w a s converted t o UFg by contact with f l u o r f n e . During t h e s e s t u d i e s , a number of materials were exposed t o gaseous f l u o r i n e and molten s a l t . Most of t h e d a t a w e r e obtained during operation1 of two plant-scale f l u o r i n a t o r s constructed of L-nickel a t temperatures ranging from 520 t o 930'6 whisk contained a number of corrosion specimens (20 d i f f e r e n t m a t e r i a l s ) . Several specimens had lower rates of maximum c o r r o s i v e a t t a c k than Ln i c k e l , and t h e specimen showing t h e least a t t a c k , Hymu 80, had a m x i mum bulk l o s s rate of 11 mils/month based on t o t a l t i m e i n molten s a l t . Other corrosion coupon tests a t 6QOQC showed that INCB-I i s also more r e s i s t a n t t o corrosion than E-nickel. Although t h e s e materials e x h i b i t b e t t e r ~ O K P O S ~ S P I I r e s i s t a n c e than L-nickel, t h i s material should have II i f protected by a froa@n-salt layer and acceptable ~ O K ~ O S ~ O behavior i s p r e f e r r e d f o r use i n MSBR processing p l a n t s s i n c e corrosion sf t h e o t h e r materials introduces v o l a t i l e f l u o r i d e s of chromium and molybdenum i n t o t h e f l u o r i n a t o r offgas.

The previous f u e l recovery operations a f f o r d u s e f u l guidelines and background information f o r t h e s e l e c t i o n of materials f o r t h e proposed process a p p l i c a t i o n s . They a l s o show t h e importance, however, of i n e r t i n g the m e t a l s u r f a c e s i n a f l u o r i n a t o r with a passive frozen-salt l a y e r . I n a d d i t i o n t o compatibility evaluations, many years of experience have been accumulated i n t h e f a b r i c a t i o n and j o i n i n g of t h i s class of a l l o y s , stemming from t h e c o n s t r u c t i o n of r e a c t o r s and associated hardware3 as w e l l as f l u o r i d e - s a l t p u r i f i c a t i o n equipment. For those p o r t i o n s of t h e process system t h a t w i l l be i n contact with bismuth o r bismuth s o l u t i o n s , conventional materials of c o n s t r u c t i o n such as Fe-, Co-, o r Ni-base alloys are not acceptable because of e i t h e r (19 excessively high s o l u b i l i t y i n bismuth OK (2) a tendency t o undergo mass t r a n s f e r when exposed t o bismuth i n a system havfng a temperature gradient. Materials which have shown good compatibility with bismuth include g r a p h i t e and r e f r a c t o r y metals such as tungsten, rhenium, molybExcept for tantalum, a16 of t h e s e materials are denum and tantalum.3'6 d i f f i c u l t t o f a b r i c a t e and joaln. A l l oxidize r a p i d l y i n a i r a t process temperatures and r e q u i r e some type of atmospheric p r o t e c t i o n .

PiscaP

year 1981 c

4-5

...

... .... :,.: 2?3

.... 8. ...

Table 4 . 2 . 1 . 2 .

Key m i l e s t o n e s f o r WBR fuel. p ~ o c e s s h g materials development

Pailea t o n e

Des e r i p t i o n

Complete c o m p a t i b i l i t y s t u d i e s r e l a t i n g t o s e l e c t i o n of t y p e of g r a p h i t e for u s e i n I n t e g r a t e d P r o c e s s T e s t Pacilfty. Complete thermal convection loop tests of molybdenum i n molten salts. I n i t i a t e f o r c e d c i r c u l a t i o n loop t e s t e w i t h g r a p h i t e i n Bi-Ei-STh.

I n i t i a t e f o r c e d c i r c u l a t i o n l o o p t e a t s w i t h molybdenum i n

BI-Li-Th (if r e q u i r e d ) . I n i t i a t e f o r c e d c i r c u l a t P o n h o p tests with tantalum i n molten s a l t s (ifr e q u i r e d ) . Complete forced c i r c u l a t i o n loop s t u d i e s . &... !a

Complete f a b r i c a t i o n development s t u d i e s w i t h g r a p h i t e .

Iete f a b r i c a t i o n s t u d i e s on molybdenum. Complete j o i n i n g s t u d i e s on molybdenum. 8

Complete j o i n i n g s t u d i e s on g r a p h i t e .

Complete s u r v e i l l a n c e program on samples from Reductive Extraction Process F a c i l i t y .

Complete s u r v e i l l a n c e program on samples from Metal T r a n s f e r Process F a c i l i t y .

----v-

-----

Table

4.2.2.1.

Bpe~ating

1075

3.2 3.3

Development and joinimg

Total fuel processin@; materials development operating funds

reqwhements %QE fuel processing (coste in 1000 dsllars)

materlala

devel9pment

Fiscal

year 1981

1982

1983

1984

1985

1076

1977

1978

1979

1986

143

166

145

100

20 l__

75 ---

75 -

30 -

123

300

393

461

489

375

of fabrication tecknfques

Construction 0% engineering %uel processing experiments

fund

1986

Table 4.2.2.2.

Summary of capital

eqUip?f~Qllt

(costs

funds required for in 1CKKl dollars)

fuel

processing Fiscal

1975 3.1 3.2

Determination mater&ah

of corrosion

Determination of fabrication joining techniques

1976

1977

450

1978

1979

materials

dQ-Ve~Q~liWt

year

1986

1981

I.982

1953

1984

1985

resistant f -4

and

Construstion of engineering fuel processing experiments Total sapltal equipment funds for processing

170

125

25 -

629

125

3.3

mater&de

development

-a-

-_-.

4-8 4.3.3 For the past several years, materials have been investigated t h a t can be used to contain Bi-Li-Th solutions at temperatures ranging from 550 to 706'C. These studies have been concentrated on molybdenum and molybdenm alloys, tantalum and tantalum alloys, and graphite. It currently appears t h a t t h e use Of graphite for vessels and mQlYbdeI8- Or molybdenum alloys for interconnecting lines, agitators, and o t h e r components represents t h e optimum combination of available materials.

.... u.s

....

E.X.

4-9

is as large as or larger than that of the startfng metal blank; t h e conf i g u r a t i o n of t h e p a r t can be changed by r e l a t i v e l y s5mple changes i n the d i e and mandrel d e s i g n ; and s u f f i c i e n t deformation can be a c c ~ m p l i s h e d t h a t a m o u g h t or fine-grained s t r u c t u r e having good mechanical p r o p e r t i e s is produced. P a r t s t h a t were free fram c ~ a c hand had h i h-quality surfaces were p ~ ~ ~ d u c econsistentlg gf with t h i s technique by the US^ of Zr82Coated plPlZEgers and d i e s and 6 2 X t K U S b n tE3llpe%atUreSQf 1600 to 1700"6. ~ B e v achsed-end forgings were produced that had a 3-7f8-in. o u t s i d e diameter, a 3.5-in. i n s i d e diameter, and lengths from 8 t o 1 2 i n . The 5.5-ft-long molybdenum p i p e for t h e e x t r a c t i o n column, having an outside diameter of l.16 i n . and an i n s i d e diameter of E i n . , was produced by f%Oating KElndKd eXtrbaSioI? at 1600Qc. Three a t $ U B i O H b S for producing t h i s material were performed; t h e second extarasion produced a p i p e 11.5 ft in l e n g t h that was c o n c e n t r i c t o w i t h i n 0.007 i n . w i t h exc e l l e n t e x t e r n a l and Lnternal s ~ ~ f a c e s .

.:.>.>A..

I n e v a l u a t i n g three siaes of comercially a v a i l a b l e molybdenm t u b i n g (llSa-, %/8-, and 1/2-im. OD), i t w a s found t h a t t h e 1/2-in. tubing w a s d u c t i l e a t room temperature, while t h e 388-in. tubing was d u c t i l e only a t t e ~ p e ~ a t u r eabove s 150 t o 256'6 and t h e l/Pa-in. tubing w a s d u c t i l e E t was found, however, t h a t t h e only a t t @ ~ i ~ p e ~ a t uabove r e s 300'C. 3/8-in. and 164-in. tubing could be made d u c t i l e a t KOOSII temperature by t h e removal of O.oo2. t o 0.08% i n . of material from the i n s i d e of t h e tubing by e t c h i n g . F u r t h f ~i n v e s t i g a t i o n showed t h a t t u b i n i s duetile a t room temperature should be produced r o u t i n e l y by c a r e f u l c ~ n t r o lof surface contamination during t u b i n g f a b r i c a t i o n .

Although helium l e a k - t i g h t molybdenum welds have been produced c o n s i s t e n t l y using both t h e electron-beam and tungsten-arc t e e b i q u e s , t h e d u c t i l e b r i t t l e t r a n s i t i o n of t h e r e s u l t i n g welds were above room temperature, and it w a s necessary t o desfgn each joint t o mechanically support t h e welds. The jo%ntswere a l s o back-brazed OK V ~ ~ Sp lKa t e d with tungeteib t o provide a SeCondaKy b a r r i e r against l e a k g e .

.... ,m ...

4-10 S t ~ d i e shave been ~ a r ~ i eo udt f o r t h e development of b r a z e materials for molybdenum t h a t are r e s i s t a n t t o c o r r o s i o n by bismuth and molten An liron-base a l l o y of the @ornpsiti.on Fe-Mo-Ge-C-B (75-15-5-4-1 w t X > has been found t o have good w e t t i n g and flow p r o p e r t i e s , a moderately Isw b r a z i n g t e m p e r a t u r e (<12008C), and a d e q u a t e r e s i s t a n c e t o c o r r o s i o n by bismuth a t 650'C.

~ ~ ~ ~ ? '

The P ~ S U ~of ~ work S t o d a t e on molybdenum f a b r i c a t i o n techniques have been q u i t e encouraging, and i t is beHiev@d t h a t the material c a n be used i n c ~ n s t r u ~ t hcomponents g f o r p r o c e s s i n g systems if p r o p e r a t t e n t i o n is given t o i t a f a b r i c a t i o n c h a r a c t e r i s t i c s .

4.3.3.2

N.... 2

Tantalum

Corrosion tests i n molten bismuth and Bf-Li s o l u t i o n s have been conducted with p u r e t a n t a l u m and t h e t a n t a l u m alloy T-111 (8% W, 2% PIf, bal Ta). In q u a r t z thermal-convection l o o p s a t ?8O9c, t h e mass t r a n s f e r rate of p u r e tantalum i n t h e s e l i q u i d metals was g r e a t e r thaw t h a t of molybdenum, although the r a t e w a s s t i l l less t h a n 3 mils/year. k s s t r a n s f e r rates for the allay T-Ill were c ~ m p a r a b l eto those f o r ~ ~ ~ o l y b d eb~u ~ t ~the m, mechanical p r o p e r t i e s of T-111 were strongly a f f e c t e d by h t e ~ a c t i ~ofn t h e a l l o y With h t E ! P S t i t h l i ? J I p U K i t i e S , prhEtrilbgp OXygen, dl2 quartz-pure-bismuth l o o p experiments. A mare r e c e n t test c a r r i e d out a t 700°C w i t h a ~i-2.5 ~t X LIB ~ ~ ~ L x t r5n ~ rae loop constructed of T-lbl t u b i n g d i d n o t measurably a f f e c t the mechanical p r o p e r t i e s of t h e T-Ill, and t h e mass t r a n s f e r r a t e w a s a g a i n f n s i g n i f i c a n t . The r e s i s t a n c e of t a n t a l u m o r T-Ill t o c o ~ r o s i o nby f u e l salt i s unknown at t h i s time, b u t i t appears marginal from t h e m ~ d y n a l ec o n s i d e r a t i o n s . However, t a n t a l u m should w i t h s t a n d attack by molten EbCl, and experiments are planned t o i n v e s t i g a t e t h i s .

4.3.3.3

Graphite

G r a p h i t e , which h a s e x c e l l e n t compatibil%ty w i t h f u e l s a l t , also shows p~cpmisef o r t h e containment of bismuth. C s m g a t i b i l i t y tests t o date have shown no evidence of chemical h t e s a c t i ~between ~~ g r a p h i t e and bismuth containin up t o 3 wt X (50 a t . X) Li. However, t h e l a r g e s t open p o r e s of most c o m e ~ c i a l l yavailable p o l y c r y s t a l l h e graphites are p e n e t r a t e d t o same e x t e n t by l i q u i d bismuth. static c a p s u l e tests6 of three e o ~ ~ ~ ~ ~g rea ~ p hci tiea9 l (ATJ, AXF-5QBG, and G r a p h i t f t e A) were

&.,

4-11 conducted f o r 500 h r a t 960'C usPng b o t h h i g h - p u r i t y bismuth and B i - 3 w t X (SO a t . 2) L i . Although p e n e t r a t i o n by p u r e bismuth w a s n e g l i g i b l e , t h e a d d i t i o n of l i t h i m t o t h e bismuth appeared t o i n c r e a s e t h e d e p t h of permeation and, presumably altered t h e w e t t i n g c h a r a c t e r i s t i c s of: t h e bismuth. Although i t is n o t h o r n whether l i m i t e d p e n e t r a t i o n of g r a p h i t e by bismuth s o l u t i o n s i s t o l e r a b l e , t h e r e are several approaches t h a t have p o t e n t i a l f o r d e c r e a s i n g t h e e x t e n t t o which a porous g r a p h i t e i s penet r a t e d by bismuth and bismuth-lithium a l l o y s . Two w e l l - e s t a b l i s h e d approaches are m u l t i p l e impregnations w i t h l i q u i d hydrocarbons which are t h e n carbonized and/or g r a p h i t i z e d and (2) gyrocarbon c o a t i n g s . Other approaches are based on vapor-deposited molybdenum c o a t i n g s , and t h e u s e of carbide-forming s e a l a n t s . Each of t h e s e s e a l i n g a p p ~ o a ~ h e s i s b e i n g e v a l u a t e d . The w e t t i n g c h a r a c t e r i s t i c s of g r a p h i t e are a l s o b e i n g s t u d i e d as a f u n c t i o n of s u r f a c e p r e t r e a t m e n t s such as d e d u s t i n g , a l c o h o l wash and oven d r y , and vacuum d e g a s s i n g a t TOO t o IOOO'C. F a b r i c a t i o n of a p r e c e s s i n g p l a n t from g r a p h i t e would n e c e s s i t a t e g r a p h i t e - t o - g r a p h i t e and graphite-to-metal j o i n t s . Development s t u d i e ~ ~have , ~ ~been conducted OR b o t h types of j o i n t s u s i n g hight e m p e r a t u r e b r a z e s and a l s o metals which band by c a r b i d e formation. S e v e r a l of t h e s e e x p e r i m e n t a l j o i n i n g t e c h n i q u e s show promise f o r t h e chemical p r o c e s s i n g a p p l i c a t i o n . Other workers1 1 9 12 have pioneered mechanieal j o i n t s which may b e s a t i s f a c t o r y f o r t h e proposed a p p l i c a t i o n .

4.3.4

Basis f o r materials s e l e c t i o n

It i s expected t h a t a combination of t h e above materials would be used i n t h e c o n s t r u c t i o n of a f u e l p r o c e s s i n g system. Although tantalum a l l o y s p r e s e n t few e n g i n e e r i n g developmental p ~ ~ b l iet ~i s~ m, p e c t e d t h a t eomp a t i b i l i t y w%th molten f l u o r i d e s and s u s c e p t i b i l i t y to environmental cont a m i n a t i o n may l i m i t t h e i r u s e . From an e n g i n e e r i n g view, t h e use of g r a p h i t e would r e q u i r e less development work t h a n molybdenum and, t h e r e f o r e , major emphasis will b e p l a c e d on s t u d i e s w i t h g r a p h i t e f o r t h e t e r m . The work o u t l i n e d f o r t h e l o n g e r term, however, allows f a r more complete development of t h e s e materials f o r more e x t e n s i v e p r o c e s s i n g a p p l i c a t i o n s . Near-term compatkbklity r e s u l t s and f u e l p r o c e s s i n g flows h e e t developments w i l l d i c t a t e t h e extent t o which subsequent work w i l l b e undertaken f o r each of t h e m t e r k a l s .

4.4

TASK GROUP 3.1

4.4.1

Obj ective

DETERMINATION OF CORROSION-RESISTANT MATERIALS

The purpose of t h i s t a s k group is t o d e t e r m i n e t h e c o m p a t i b i l i t y of p o t e n t i a l container materials with fuel processing system environments under s i m u l a t e d f u e l p r o c e s s i n g c o n d i t i o n s . Materials b e i n g i n v e s t i g a t e d i n c l u d e molybdenum, t a n t a l u m a l l o y s , and g r a p h i t e .

4-12

4.4.2

Schedule

%he schedule for work in this task group is shown in Table 4.4.2.

4.4.4

Facilities

This task group wil1 require use of the following facilities:

4.4.5

Task 2.1.1 Compatibility of mofybdenum with molten salts and Bi-Li-Th solutions

The c ~ r r o s i o nof molybdenum in molten salt can probably b e described by the KeaCtiOn:

When compared with f l ~ o ~ i d of e s other elements present in the system, MoF6 is r e l a t i v e l y unstable, and it seems unlikely that any s e ~ i o u s a t t a c k sf mdgrbdenum by the fuel carrier salt will occur. To v e r i f y this hypothesis, a thermal convection loop teat will be constructed of m I y b d e n m and operated with f u e l carrier s a l t at a maximum t m p e ~ a t ~ r e of 780°C and a t e m p e r a t u r e difference of approximately 100°C. T e s t coupons and tensile samples will be included in both h o t and cold sections. In addition to mechanical p r o p e ~ t i e schanges, evaluation of loop components will be obtained from weight-change measurments, chemical analyses, and metallographic examination.

Table 4.4.2.

Scheule fasr wmk in Task Group 3.1 - Determination of corrosion-resistant materials

3.1.1

Compatibility of mdybdenum and molybdenum alloys with molten salt5 and Bi-Li-Th SQlutiQns 3.1.1.1 Tklermal convectian loop tests in molten salt 3.1.1.2 F~raxl circulation k9op tests in Bi-Li-Th solutions 3.1.1.3 Corrosion tests of malybdenumcoated eompanents

3.1.2

Compatibility of graphite wfth Bi-Li-Th solutions X.1.2.1 Penetration af graphite as a function of Li in bismuth and type of graphite 3.1.2.2 Studies of intercalation compounds with graphite 3.1.2.3 SoPubility of carbon in Bi-Li 3.1.2.4 Thermal cmnvection losp tests in Bi-Li 3 .1.2.5 FQPced cfrculatisn loop tests in Bi-Li-Th solutians

3.1.3

Compatibility of tantalum and tantalum allays with molten salts and Ai-Li-Th solutims 3.1.3.1 TRermal canvectian Itpop tests Ta-10% W in molten salt

Table

4.4.2

(continued) Fiscal

3.1.3.2 3.1.3.3 3.1.3.4

3.1.4

Foreed circu%ation mQlten salts Thermal convection Bi-E.i Fsrced circulation Bi-LA-l% solutions

loop

tests

losp

tests

lacap tests

Compatibi.lity of braze alloys with molten salts and Bi-Eli-T% sol.utisns 3.1.4.1 Capsule tests 3.1.4.2 Thermal convection loop tests 3*1.4.3 Psrced circulation loop tests

year

Table 4.4.3.1.

Operating fund requirements for Task Croup 3.1 - Determination of corrosion-resistant materials (costs in 1000 dollars) Fiscal 1975

3.1.1

Compatibility of molybdenum and molybdenum alloys with molten salts and Bi-Li-Th solutions 3.1.1.1 Thermal convection loop tests in molten salt 3.1.1.2 Forced circulation loop tests in Bi-Li-Th solutions 3.1.1.3 Corrosion tests of molybdenumcaated components Subtotal

3.1.2

Subtotal

3.1.2

1977

1978

19 79

1980

80 80

10 40

3.1.1

Compatibility of graphite with Bi-Li-Th solutions 3.1.2.1 Penetration of graphite as a function of Li in bismuth and type of graphite 3.1.2.2 Studies of intercalation compounds with graphite Solubility of carbon in Bi-Li 3.1.2.3 3.1.2.4 Thermal convection losp tests in Bi-Li 3.1.2.5 Forced circulation loop tests in Bi-Li-Tb solutions

1976

year

20 15 20

1981

- -

Table 4.4.3.1

(continued) Fiscal

3.1,3

1975

1976

year

1977

I.978

1979

34 109

8Q 80

5 5

1980

Compatibility of tantalum and tantalum alloys with mslten salts and Bi-Li-Th SOlUtiOn.5

3.1.3.1 3.1.3.2 3,1.3.3 3.1.304 Subtotal 3.11.4

Total

Thermal convection loop tests Ta-10% W in molten salt Forced circu%ation loop tests molten salts Thermal convection hap tests Bi-IA.. FO%cxd cir@ulation Boop tests Bi-Li-Tb solutioms

in in

3.1.3

Compatibility of braze alloys with molten salts am9 Bi-ki-Th solutions 3.1.4.1 Capsule tests 3 ml.4.2 Thermal convection losp tests 3.1.4.3 Forceil circulation laop tests Subtotal

3.1.4

aperating

funds for Task Group 3.1

15 5

8 2

10 ____ 200

118

185

1L 220

264

200

1981

Table 4.4.3.2. Capital fund requirements for work in Task Group 3.1 Determination of corrosion resistant materials (costs in lOOtI dollars) Fiscal 1975 3.1

Detertinastion of corrosion resistant materials 3.1.1.2 Forced circulation loop test in Bi-Li-m (molybdenum) 3.lb.l.3 Corrosion tests af molybdenum coated components 3.1.2.4 Thermal convection loop tests %.1.2.5 Forced-circulation loop tests with EC-M soPutians (graphite) 3.1.3.2 Forced-circulation loop tests with molten salt (tantalum) Forced-circulation Poop tests with 3.1.3.4 Bi-Li-Th solutisns (tantalum)

Total

capital

fund requirements

for Task Group 3.1.

satisfactory

of these facilities material far fuel

will not be required processing systems.

* CkmitructiOn

year

1977

1376

1978

800* BO 75 450 fKm* 85 if

graphite

___ 450 is

shown

800"

to be a

1979

4-18

Subtask 3.1.1.2 solu t ions

Forced-circulation loop t e s t with Bi-Li-Th

eomgatible with B i - L i s ~ l u t i o n sunder dynamic conditions. Additional allow f u r t h e r testing Under coPldithnS forCed-ciKculat8on loop tests mor@ closely S i l d . a t i n g pHQcessing COnditfOnS, and a mOlybd@ltraaam loop Will be constructed as a test-bed f a c i l i t y . The design of t h e loop will a l l o w f o r removal of samples that w i l l be exposed under varying conditions. Solutions of Bf-I&$-Th eomtaining f i s s i o n product elements will be circul a t e d a t v a r i a b l e flow rates, and corrosion rates of molybdenum w i l l be determined as a function of flow rate, f l u i d composition, and temperature difference 0

The coating s f c o n ~ e n t i o ~ materials al suck as iron- o r nickel-base a l l o y s with molybdenum, which does not r e q u i r e c o ~ ~ ~ p l i c a ft ea bd r i c a t i o n and j o h ing procedures, has been under consideration as a technique for providing Two types of coating ~ K O C far: chemical-vapor d e p o s i t i o n by hydrogen reduction of MoF6 and d e p o s i t i o n Zrsm molten-salt mixtures cont a i n i n g M Q F ~by chemical r e a c t i o n wfth the s u b s t r a t e . The l a t t e r method Books @specially promising because more complicated components could probably be coated using t h i s approach. I n v e s t i g a t i o n s of coating processes and v a r i a b l e s will be continued. The K e f f e c t i v e n e s s can best be determined from compatibility t e s t s i n Bi-Li s o l u t i o n . Both s t a t i c and thermal-convection loop tests w i l l be conducted and evaluation will cansist primarily of chemical analyses of t h e s o l u t i o n s and metallographic e x d n a t i o m of the coated samples.

resistance t o c o r r o s i o n by B i - L i solutions, e s s e s have been investigated thus

4.4.6.1

Subtask 3.1.2.1 Penetration of g ~ a p h f t eas a f u n c t i o n of l i t h i m concentration and type of g r a p h i t e

The purpose of t h i s subtask is t o determine t h e types of g r a p h i t e t h a t w i l l be s a t i s f a c t o r y f o r use gn c o n s t r u c t h g f u e l processing systems and t e s t s have shorn experiments which contain BI-Li ~ ~ l u t f ~ nCompatib2lity s . t h a t bislllllth an61 B i - L i S Q l U t i O R s penetrate the aCCeSSfb%@porosity Of SOmC? graphgtes, amd i n s e v e r a l tests with low-quality graphite Bi-Li s o l u t i o n s have penetrated t h e g r a p h i t e completely. Capsule tests w i l l be continued t o d e t e m l n e the extent of p e n e t r a t i o n as a f u n c t i o n of time, g r a p h i t e pore size, gPaphPt@ d e n s i t y , and t h e COnC@ntrationS Of lithium and fiSS%Qn product elements i n Bi-Li solutions. The e f f e c t i v e n e s s of l i q u i d impregn a t i o n , pyrolytfc coatings, and refractory-metal coatings f o r reducing t h e e x t e n t of p e n e t r a t i o n w i l l be evaluated. Studies w i l l ~ B S Qbe c a r r i e d out in which graphLtes that are pemeated by bismuth s o l u t i o n s are thermal cycled over a t e q e r a t u r e range ineluding t h e s o l u t i o n solidus temperature in order t o determine the allowable extent of permeation.

h .

4-19

4.4.6.2

Subtask 3.1.2.2 Studies t o determine whether Bi-Li-Th s o l u t i o n s i n t e r a c t chemically with g r a p h i t e

,.;s

Some materials react with g r a p h i t e t o form lamellar o r i n t e r c a l a t i o n cosipounds. These compotmnds are formed by chemical i n t e r a c t i o n a t t h e edge of t h e carbon Payer planes and d i f f u s i o n of t h e r e a c t a n t i n t o t h e g r a p h i t e between t h e l a y e r planes. Compounds of t h i s type are known t o form with a l a r g e number of s a l t s , a few oxides, f l u o r i n e , chlorine, bromine, potassium, rubidium, and cesium. Experiments conducted thus f a r have not shown i n t e r c a l a t i o n compound formation with B i - L i s o l u t i o n s a t 650°C. Studies w i l l be continued t o i n v e s t i g a t e t h e e f f e c t of temperature and t h e presence of f i s s i o n product elements such as cesium i n B i - L i sobutions on i n t e r c a l a t i o n compound formatiom. Studies w i l l also be c a r r i e d out f o r determining t h e extent t o which elements dissolved i n bismuth i n t e r a c t with g r a p h i t e t o form metal carbides, and f o r observing t h e e f f e c t of c a r b i d e formation on t h e p r o p e r t i e s of t h e base graphite.

..,..... ..

4.4.6.3

..... ~.:.xa

.....

Subtask 3.1.2.3 Determination of the s o l u b i l i t y of carbon i n Bi-LI solutions

The s o l u b i l i t y of carbon i n bismuth has been reported16 to be 4 ppm a t 750'C. I n a thermal-eonvection- loo^ t e s t i n which g r a p h i t e w a s fn contact ( m s > and with a 100°C temperature with Bi-PO0 ppm L i f o r 30QO hr a t 70Q'C d i f f e r e n c e between t h e hot and cold l e g s , corrosion and mss t r a n s f e r were not s i g n i f i c a n t . However, r e c e n t capsule t e s t r e s u l t s a t 658°C have imdicated s i g n i f i c a n t l y higher carbon s o l u b i l i t i e s i n Bf-3 wt X Li. Because rapid mss t r a n s f e r k i n e t i c s have been observed i n bismuth syst m s with materials having s o l u b i l i t i e s ranging from 50 t o 100 ppm, it is important t h a t t h e s o l u b i l i t y of carbon i n B i - L i so.lutions be ~ Q R a c c u r a t e l y determhed. One important f a c t o r i n t h e determination i s prot e c t i o n of t h e B i - L i samples from exposure t o a i r following e q u i l i b r a t i o n with g r a p h i t e . When l i t h i u m i s exposed t o a i r , a s u r f a c e product believed t o be Liz683 r e s u l t s . Thus, spuriously high carbon values can b e obtained i f proper sampling and a n a l y s i s techniques are not used. Samples of various types of g r a p h i t e w i l l be exposed t o Bi-100 w t ppm L i , B i - l w t X Lis Bi-2 w t X Li and Bi-3 w t 2 E i f o r 1000 and 3000 hr a t 650'C. Carbon concentrations i n t h e m e l t w i l l be determined as a function of Lf conc e n t r a t i o n , e q u i l i b r a t i o n t h e , and type of graphite. 4.4.6.4

Subtask 3.1.2.4 solutio^

Thermal-convection loop tests with B i - L i

One of t h e p r i n c i p a l c o m p a t i b i l i t y p r o b l e m between g r a p h i t e and bismuth is mass t r a n s f e r i n systems having a temperature gradient. Rapid k i n e t i c s of d i s s o l u t i o n and d e p o s i t i o n have r e s u l t e d i n s i g n i f i c a n t mass t r a n s f e r of i r o n and niobium even though t h e i r s o l u b i l i t i e s i n bismuth are only If t h e s o l u b i l i t y of g r a p h i t e i s appreciable 58-100 ppm a t 600 t o 700'C. i n bismuth containing 2 t o 3 wt X E i , mass t r a n s f e r of g r a p h i t e may be a

4-20

significant problem. Graphite samples w i l l be evaluated i n i t i a l l y in a molybdenum thermal-convection l o o p i n which Bi-3 wt X Li w i l l be e i ~ ~ ~ l a t e d at a aoo"e tn~illlllllltemp@PatUKe. men Sat8sfaCtOV j o i n i n g pPocedUlfes have been developed, a graphite loop will be constructed and the test will be r e p e a t e d with a Bi-3 wt % Li solution. Tests w i l l be contiwered t o evaluate several grades of graphite using Bi-Li s o l u t i o n s , which in s o m e cases will contain fission-product elements.

These tests will b e an extension of

those d e e e r i b e d above i n Subtask The approach will b e to construct a graphite loop t e s t - b e d facility in which samples sf various types of g r a p h i t e can b e included. Va~iableswill include flow rate, temperature difference, and composition sf t h e Bi-Li solutions. 3.1.2.4.

4.4.7 4.4.7.1

Task 3 . 1 . 3 GompatibilBty of t a ~ t a l mand tantalum a l l o y s with molten s a l t s and Bi-Li solutions Subtask 3.1.3.1

ts..

The~~nal-c~n~ectio~~ loop t e s t with molten s a l t

The thermodynamic stability of TaF2 at 600-708"C is comparable to that of CrF2. Since t h e activity of tantalum i n unalloyed tantalum OK Ta-10% W is higher than t h a t of c k r o ~ min HastelPsy N, its corrosion rate will probably be somewhat higher f O K a given redox potentid than that f o r ChrBIBiUEl, EUId t h e rat@Qf attack W i l l not be diffusion E i d . t @ d 88 W O U l d be the case f o r attack of ~Baro~im in H a s t e l P ~N ~. ~ A series of t h e m d convection loop tests will be carried out to evaluate tantalum a d tantalm d l ~ p .Initially, a loop will be constructed of the alloy 9OX Ta-10% W which will be used to circulate MSBR fuel carrier s a l t at a maximum temperature Of 700°C With a telBperatUre diffeke@l.aC!@ Of apprQXhlately loooc. Tabular a d tensile specimens will be ine%uded in both the hot- and soldleg sections. Evaluation w i l l consist of weight and mechanical propert i e s changes chemical analyses and meta1lographBc examination. Additional tests as i n d i c a t e d will be conducted in w g t i ~ htime and a l l o y D B t e K i a l a%e Varied. 4.4.7.2

Subtask 3.1.3.2

Fo~ced-ci~~~Pation loop t e s t s with molten salt

These t e s t s w i l l b e isl% extension of those d e s c r i b e d above in Subtask 3.1.3.1, with conditions more closely simulating a f u e l p r o c e s s i n g system. A test-bed f a c i l i t y will be ~ ~ n s t r u c t eof d the mst pro&sif~ tantalum alloy and test variables will include time, flow rate, temperature d i f f e r e n c e , and ~ + 4 , W 3 ratio. ~emovablesamples w i ~ l ibe included in several sections of the loop.

k..:

4-21

4.4.7.3

Subtask 3 . 1 . 3 . 3

" h e m a l - c o n v e c t i o n loop tests w i t h Bi-Li-m

8 o Put i o n s

Subtask 3 . 1 . 3 . 4

I n thermal-convection l o o p tests of T - I l l i n Bi-2.5 e s t X Li, mass t r a n s f e r rates w e r e l o w (cumparable t o t h o s e for molybdenum). If t h e r e s u l t s from tests w i t h Ta-10% W i n m d t e n s a l t are promlsing (Subtask 3.1.3.1) a thermal-convection loop w i l l b e c o n s t r u c t e d of Ta-10% W t o c i r c u l a t e Bi-2.5 wt X Li a t 708'C (maximum) w i t h a POOQC: teIIIpelfatuK€? d i f f e r e n c e . Test coupons and t e n s i l e specimens w i l l b e i n c l u d e d i n both hot and c o l d s e c t i o n s . In a d d i t i o n t o mechanical p r o p e r t i e s c h a ~ g e se~v a l u a t i o n sf components w i l l b e made by weight change measurements, chemical a n a l y s e s , and m e t a l l o g r a p h i c examination. A d d i t i o n a l tests w i l l be n e c e s s a r y t o e v a l u a t e t h e e f f e c t of Bi-Ei composition i n c l u d i n g t h e a d d i t i o n of f i s s i o n product ePements.

4.4.7.4

F o r c e d - c i r c u l a t i o n loop tests w i t h Bi-Li-Th

s s l u ti o n s

F o r c e d - c i r c u l a t i o n loop tests u s i n g Bi-Li-'I% s o l u t i o n s w i l l be r e q u i r e d t~ more c l u s e l y s i m u l a t e p r o c e s s i n g c o n d i t i o n s . A t a n t a l u m allboy loop (probably Ta-POX W) w i l l b e c o n s t r u c t e d as a t e s t - b e d f a c i l i t y i n which removable smples can b e exposed under v a r y i n g conditions. S o l u t i ~ ~sf s Bi-Li-Th c o n t a i n i n g f i s s i o n product elements w i l l b e c i r c u l a t e d a t v a r i a b l e flow rates. Corrosion rates of t a n t a l u m a l l o y s w i l l b e measured as a f u n c t i o n of s o l u t i o n composition, flow r a t e , temperature, and temperature difference.

4.4.8

Task 3.1.4 C o m p a t i b i l i t y of b r a z e a l l o y s w i t h molten salts and Bi-Li-Th s o l u t i o n s

Brazing w i l l b e a very i m p o r t a n t j o i n i n g p r o c e s s i n making graphite-tsgzpaphite, grapkitg-to-msPgrbdennum and, perhaps, moly~denum-to-moPybdels~ j o i n t s . Although i t i s l i k e l y t h a t some p o r t i o n s of io p r o c e s s i n g p l a n t w i l l r e q u i r e b r a z e d - j o i n t c o n s t r u c t i o n , t h e use of t a n t a l u m a l l o y s w i l l n o t b e as dependent on development of a b r a z e a l l o y because tantalum a l l o y s are more r e a d i l y w e l d a b l e t h a n o t h e r p o t e n t i a l materials of cons t r u c t i o n . One of t h e major requirements of a b r a z e a l l o y is compatib i l i t y w i t h molten s a l t and Bi-Li-Th s o l u t i o n s . In a d d i t i o n , f o r j o i n t s i n v o l v i n g molybdenum, the m e l t i n g p o i n t of t h e b r a z e a l l o y s h o ~ l dbe l o w enough t h a t molybdenum, whish i s s t r u c t u r e s e n s i t i v e , does n o t r e c r y s t a l have shown promise f o r t h i s l i z e d u r i n g b r a z i n g . Alloys of Fe-C-E-Mo-Ge a p p l i c a t i o n . Braze a l l o y s for g r a p h i t e g e n e r a l l y c o n s i s t of metals o r d l o y a t h a t are s t r o n g c a r b i d e formers such as molybdenum o r t i t a n i u m , b u t work w i t h t h e s e materials h a s been l i m i t e d .

4-22

4.4.8.1

Subtask 3.1.4.1

Capsule tests

I n i t i a l b r a z e d - j o i n t e v a l u a t i o n w i l l c o n s i s t of exposure of samples to s a l t H n i X t U r e s OK Bi-Ei solutions in k5o~hCtTlEdcapsubes, and t h i s type of s c r e e n i n g e v a l u a t i o n w i l l e l i m i n a t e a l l o y s which show l i t t l e promise. Conditions such as t i m e , temperature and composition sf t h e f l u i d s w i l l be v a r i e d . 4.4.8.2

Subtask 3 . 1 . 4 . 2

Thermal-convection loop tests

Braze a l l o y s which show promise i n t h e s c r e e n i n g c o m p a t i b i l i t y tests w i l l b e e v a l u a t e d f u r t h e r i n t h e thermal-convection loop tests d e s c r i b e d in Subtasks 3.1.1.1, 3.1.2.4, and 3.1.3.1. I n i t i a l l y , b r a ~ e d - j o i n t test coupons w i l l b e e v a l u a t e d , but s u b s e q u e n t l y , l o o p s w i l l b e e o n s t r u c t e d w i t h brazed j o i n t s and t h e s e w i l l be e v a l u a t e d as a f u n c t i o n o f brazea l l o y compositfon, t i m e , and f l u i d composition. 4.4.8.3

Subtask 3.1.4.3

F o r c e d - c i r c u l a t i o n loop tests

Thfs is an e x t e n s i o n of Subtask 3.1.4.2, above. Brazed joints will be included as samples i n several s e c t i o n s of the t e s t - b e d l o o p s d e s c r i b e d i n Subtasks 3.1.1.2, 3.1.2.5, and 3.1.3.2. The v a r i a b l e s t o b e s t u d i e d w i l l c o n s i s t of temperature, temperature d i f f e r e n c e , t i m e , flow v e l o c i t y , a d C X I m p O s i t i O n Of the f l u i d .

4.5 1 O b j e c t i v e e

The purpose of t h i s t a s k group i s to develop f a b r i c a t i o n and j o i n i n g techniques f o r materia%s that w i l l b e used i n c o n s t r u c t i n g l a r g e - s c a l e engineeri n g f u e l p r o c e s s i n g experiments. These s t u d i e s w i l l also prove v a l u a b l e ing t h e f i n a l s e l e c t i o n of m t e ~ i a l st o b e used i n c o n s t r u c t i n g a fuel processing f a c i l i t y . 4e 5 2 0

Schedule

me schedule for this t a s k group is shown i n Table 4.5.2. 4.5 e 3

Funding

4.5.4

Facilities

This task group w i l l r e q u i r e t h e use of t h e f o l l o w i n g f a c i l i t i e s :

Table 4.5.2.

Schedule for work in Task Group 3.2 -Development of fabrication and joining techniques Fiscal

3.2.1

Fabrication development of molybdenum and molybdenum alloys 3.2.1.1 Effect of very low concentrations of oxygen and carbon on deformation behavior 3.2.1.2 Effect of fabrication processes and variables on the mechanical propeaies 3.2.1.3 Grain size control during secondary fabricatian processes 3.2.1.4 Molybdenum alloy studies to improve ductility af base material

3.2.2

Fabrication development tantalum alloys

of tantalum

and

3.2.3

Fabrication development of graphite 3.2.3.1 Evaluatian of resistance of commercially available graphites to penetration by bismuth 3.2.3.2 Development and evaluation of procedures to reduce bismuth penetration in commercial graphite

_____ -

year

Fiscal

3.2.4 Joining of mlybdenumand malybaen~lm alloys 3.2.4.1

3.2.4.3

Development sf molybdenum alloy with fmproved resistance to contamination induced emhrittlenlent al-d/or cracking Effect Qf jsining processes and variables an welding and mechanical properties Braze alloy development studies

3e2.4.4

Mechanical

Joining 3.2.5.1

of tantalum and tantalum alloys Effect of joining processes and variablbes on welding and mechanical properties Brazing development studlies

3.2.4.2

3.2.5

3.2.5.2 3.2.4

Joining 3.2.6,1 3.2.6.2 3.2.6.3 3.2.6.4

joint

devePopment

of graphite Brazing develapment studies Adhesive boding studies High-temperature diffusion bonding studies Mechanical joint Stxdi@S

year

Table 4.5.3.1.

Operating fund requirements for Task Group 3.2 - Development of fabrication and joining techniques (costs in 1000 dollars) Fiscal

3.2.1

Fabrication development of molybdenum and molybdenum alloys 3.2.lb.lEffect of $ery low concentrations of oxygen and carbon on deformation behavior 3.2.1.2 Effect of fabrication processes and variables on the mechanical properties 3.2.1.3 Grain size control during secondary fabrication processes 3.2.1.4 Molybdenum alloying studies to improve ductility of base material Subtotal

3.2.2

Fabrication development tantalum alloys Subtotal

3.2.3

3.2.1

10 6Q

year

15 30

20 20

50 5Q

16 16

20 20

of tantalum and

3.2.2

Fabrication development of graphite 3.2.3.1 Evaluation of the resistance of commercially available graphites to penetration by bismuth

3.2.4

Joining

of molybdenum and molybdenum

LallSYS

3.2.4.1

3.2.4.3 3.2.4.4

Development of malybdenum allay with improved resistance to contamination induced embrittlemewt andlsr cracking Effect sf joining processes and variables on welding and me&anical properties Braze alloy develapment studies MechanicaIL joint development

Subtotal

3.2.4

Joining 3.2.5.1 3.2.5.2

of tantalum and tantalum alloys Effect of joining processes and variables on welding and mechanical properties Brazing development studies

Subtotal.

3.2.5

3.2.4.2

3.2.5

10 18

15 15

5 30

10 25

5 5

15 1s 30

5 10 15

Table 4.5.3.1

(continued) Fiscal 1975

3.2.6

Total

Joining 3.2.6.1 3.2.6.2 3.2.6.3 3.2.6.4

of graphite Brazing. development studies Adhesive bonding studies High-temperature diffusion bonding studies Mechanical joint studies

Subtotal

3.2.6

operating

funds for Task Group 3.2

year

1976

B977

1978

1979

10 1Q

10 10

30 20

5 5

2Q PQ 80

40 20 70

20 95

143

P66

165

1988

198%

15 15

1QQ

---

Table

3.2

Total

4.5.3.2.

Capital DevelQpment

fund requirements fm WQk"k in Task of Fabrication and joining techniques (costs fw 10QB dallars)

Develspment a% fabrication and joining techniques %ar materials selected far engineering 63cperiments 3.2.1.2 Deternine the effect af fabrication pracesses and varfabhxs on the mechanical. properties 3.2.1.4 Malybdenum allaying studies to improve ductiPity of base material 3.2.2 Pabricatian development 0% tantalml and tantal.um alloys 3.2.4.1 Develsgment af molybdenum with imprsved resistance to csntamination-induced embrittlement and/or cracking 3.2.4.2 Determine the effect of joining processes variables cm welding and mechanical prsperties 3.2.6.3 High-temperature diffusion-banding studies 3.2.6.4 Mechanical-jofnt studies capital

equipment

Tunds

for

Task

Grcmp

3.2

Grsup

3.2

-. -

4-29 B u g . 4588, wm. 225 - A I 1 e l e c t r o n Bern welding will b e done w i t h t h e 6-m Hamilton Standard e l e c t r o n - b e m welder i n t h i s room.

$lag. 4508, m. 226 tungsten-arc welding (including s p o t V a r e s t r a i n t tests) w i l l b e c a r r i e d out i n t h e glove box i n this room. It w i l l b e necessary t o provide an i m p u r i t y a d d i t i o n euad monitoring system for t h e chamber i n o r d e r t o conduct Subtask. 3.2.4.1. 4508, %pw. 223 and am. 224 - B r a z i n g out i n the f u r n a c e s i n t h e s e rooms. e

studies w i l l be carried

Blldg. 4508, WW. 130 - F a b r i c a t i o n s t u d i e s w i l l b e carried o u t using t h e f a c i l i t i e s of t h e Castfng and Forming Technology Group. These i n c l u d e arc and electron-beam m e l t i n g furnaces, vacuum heat t r e a t i n g f u r n a c e s , swagers, cold and h o t rsE%ing equipment, and a h o r i z o n t a l e ~ t r u s i o np r e s s .

Bldg. 3812 - Tube reducing and l a r g e - s i z e plate and s h e e t r o l l i n g w i l l b e done w i t h t h e equipment i n t h i s b u i l d i n g . Some work w i l l b e done i n c o n j u n c t i o n w i t h e s m e r F c a l vendors amd will require use of t h e i r f a c i l i t i e s .

4.5.5

Task 3 . 2 . P alloys

F a b r i c a t i o n development of mlybdenum and molybdenum

The o b j e c t i v e of t h i s t a s k is bo e v a l u a t e t h e existing p r o c e s s e s fog. f a b r i c a t i o n of molybdenum and t o develop improved methods and materials t h a t w i l l f a c i l i t a t e t h e use of molybdenm o r molybdenm a l l o y s in fuel p r o c e s s i n g systems.

4.5.5.1

Subtask 3.2.1.1 E f f e c t of very Bow c o n c e n t r a t i o n s of oxygem and carbon OR deformation b e h a v i o r

V e r y l i t t l e work has been p u b l i s h e d on t h e e f f e c t s of very low concent r a t i o n s of oxygen and carbon on t h e d ~ f s m a t i ~b enh a v i o r of molybdenum. Recent advaaees in m e l t i n g technology have r e s u l t e d i n p r o d u c t i o n of veryh i g h - p u r i t y b a s e metal which causes v a r i a t i o n s i n t h e r e q u i r e d g a r m e t e r s f o r deformation. The l e v e l s of b o t h oxygen and carbon d i c t a t e the temp e r a t u r e r e q u i r e d for forming and t h e f o r c e s t h a t are necessary. Impurity l e v e l s a l s o have an e f f e c t on g r a i n s i z e of the s t a r t i n g b l a n k which i n t u r n changes t h e f a b r i c a t i o n p a r m e t e r s . The e f f e c t s of i m p u r i t y hvePs w i l l b e s t u d i e d by e x t r u s i o n , back e x t r u s i o n and tube drawing of s e l e c t e d h e a t s of material, m d by comparison of t h e f a b r i c a t i o n parameters r e q u i r e d f o r each material. Products w i l l b e e v a l u a t e d v i s u a l l y %md metallographi c a l l y t o determine g r a i n s i z e and E ~ K O S ~ K U C X U ~ ~ .

4- 30

4.5.5.2

Subtask 3.2.1.2 E f f e c t of f a b r i c a t i o n prceeesses and variables on mchanieal p r o p e r t i e s

o r d e r to assist t h e design and conStpuCtiC8n of IW3lybdenbPm COmpOlX3ltS for p r o c e s s i n g s y s t e m , i% will b e n e c e s s a r y to i n v e s t i g a t e t h e e f f e c t

of f a b r i c a t i o n p r o c e s s e s and v a r i a b l e s on mechanical p r o p e r t i e s . L i t t l e mechanical p r o p e r t i e s data is available on molybdenum p r o d u c t € o m except for saall diameter rod and s h e e t . This e f f o r t w i l l u s e extrusisn, back e x t r u s i o n and t u b e drawing t o produce a wide range of specimens for evaluation. F a b r i c a t i o n v a r i a b l e s w i l l i n c l u d e forming t e m p e r a t u r e s , deformation rates and in-process heat t r e a t m e n t . Mechanical p r o p e r t i e s tests w i l l i n c l u d e measurements of toughness, t e n s i l e streng~h,and ductility as a f u n c t i o n of temperature a d s t r a i n rate. 4.5.5.3

Subtask 3.2.1.3 Grain s i z e control d u r i n g secondary f a b r i c a t i o n processes

Pine-gPained mlgrbdenm g e n e r a l l y is easier to f a b P i c a t e a d h a s b e t t e r mechanical p r o p e r t f e s than material having a l a r g e r g r a i n s i z e . I n o r d e r t o f a c f l i t a t e making molybdenum components for p r o c e s s i n g s y s t e m , it will b e n e c e s s a r y t o carry o u t s t u d i e s on the c o n t ~ o lof grain size d u r i n g secondary f a b r i c a % i ~ n . Rotary f o r g i n g of barge-diameter p i p e , back ext r u s i o n of s h a p e s , and tube drawing will b e used i n t h e s t u d y . %e e f f o r t will be of much wider scope t h a n that used p r e ~ i ~ u s lon y the p ~ o d ~ t l e o n of C Q I X U I E K ~ C arc-cast ~~ tubing.

4.5.5.4

Subtask 3.2.1.4

Holydenurn a l l o y f n g studfes t o improve

ductility of base material L i t t l e , i f m y , work has been p u b l i s h e d on t h e a l l o y i n g of molybdenum to improve d u c t i l i t y because most work h a s been d i r e c t e d towards i n c r e a s i n g t h e base-metab s t r e n g t h . This e f f o r t w P l l e v a l u a t e t h e e f f e c t i v e n e s s OB small a l I s y i n g a d d i t i o n s f o r c l e a n i n g up g r a i n b o u n d a r i e s and c o n t r o l l i n g grain size. Elements such as yttrium, hafnium, titanium, and zirconium have sometimes proved e f f e c t i v e as oxygen and carbon s c a v e n g e r s . Bareearth and boron a d d i t i o n s have been reporteda7 t o improve crack r e s i s t a n c e . me a d d i t i o n of rhenium improves t h e d u c t i f i t y of molybdenum c o n s i d e r a b l y , a d the d l o y -50% 2s reasonably f a b r i c a b l e and weldable. However, high coat a d limited a v a i l a b i l i t y of rhenium make t h i s a l l o y less des5ra b l e e Alloys containing small c s n c e n t r a t i o n s of rhenium i n combination with other elements such as those d i s c u s s e d above w i l l b e i n v e s t i g a t e d .

4.5.6

Task 3.2.2 alloys

F a b r i c a t i o n development of tantalum and tantalum

Tantalum agld tatntalm-base a l l o y s are not c o n s i d e r e d t o b e difficult to f a b r i c a t e because ( ~ ft h e i r good ductility. A f t e r a p a r t i c u l a r tantalumb a s e &loy has been s e l e c t e d f o r w e i n f u e l p r o c e s s i n system p work i n

.... Lxc.:

&."

4-31

d.2

t E i s s u b t a s k w i l l be c a r r i e d o u t t o review f a b r i c a t i o n process methods and t o determine optimum process parameters. I n a d d i t i o n , t h e e f f e c t of s u r f a c e contamination during forming and f a b r i c a t i o n w i l l be determined. The e f f e c t of s u r f a c e c o a t i n g s used f o r both p r o t e c t i o n and l u b r i c a t i o n d u r i n g forming w i l l be evaluated by chemical a n a l y s i s and changes i n mechanical p r o p e r t i e s . Methods of f a b r i c a t i o n w i l l i n c l u d e e x t r u s i o n , r o l l i n g , and drawing. Minor base-metal and a l l o y a d d i t i o n s w i l l be inv e s t i g a t e d t o determine whether they improve f a b r i c a t i o n parameters and products. 4.5.7

Task 3 . 2 . 3

F a b r i c a t i o n development of g r a p h i t e

The main f a b r i c a t i o n problem a s s o c i a t e d w i t h g r a p h i t e f o r t h i s a p p l i c a t i o n i s making i t impervious to p e n e t r a t i o n by Bi-Lf s o l u t i o n s . Since t h e g r a p h i t e used i n chemical processing systems w i l l n o t b e exposed t o s i g n i f i c a n t neutron f l u e n c e s , g r a p h i t e % of poor c r y s t a l l i n e p e r f e c t i o n can be used. Rather t h a n making t h e e n t i r e g r a p h i t e body impervious, t h e f a b r i c a t e d components w i l l be s u r f a c e s e a l e d by l i q u i d o r gaseous impregnation. 4.5.7.1

Subtask 3 . 2 . 3 . 1 Evaluation of t h e r e s i s t a n c e of c o m e r c i a l l y a v a i l a b l e g r a p h i t e s t o p e n e t r a t i o n by b i s m u t h - l i t h h m s o l u t i o n s

Compatibility tests have shown t h a t B i - L i s o l u t i o n s w i l l p e n e t r a t e t h e open p o r o s i t y of some types of g r a p h i t e while high-density, low-porosity g r a p h i t e s almost completely resist p e n e t r a t i o n . Determfnation of t h e t y p e of g r a p h i t e r e q u i r e d f o r f u e l processing experiments and p l a n t conBased on r e s u l t s from t h a t s t r u c t i o n i s t h e o b j e c t i v e of Subtask 3 . l . 2 , l . W Q K ~ , commercial g r a p h i t e t h a t i s a v a i l a b l e i n t h e s i z e ranges t h a t are r e q u i r e d f o r f u e l processing a p p l i c a t i o n s w i l l be evaluated by exposure to Bi-Li s o l u t i o n s . Since pore s i z e and pore a c c e s s i b i l i t y of commercial g r a p h i t e s o f t e n vary considerably, one important f a c t o r i n t h i s study w i l l be a s t a t i s t i c a l determination of t h e v a r i a b i l i t y of these c h a r a c t e r i s t i c s f o r a p a r t i c u l a r grade of grapRite.

4.5.7.2

Subtask 3 . 2 . 3 . 2 Development and e v a l u a t i o n of procedures to reduce bismuth p e n e t r a t i o n i n commerical g r a p h i t e

I f commercially a v a i l a b l e g r a p h i t e s do not adequately resist p e n e t r a t i o n by B i - L i s o l u t i o n s , s u i t a b l e s e a l i n g procedures w i l l be developed. Enqphasis w i l l be on conventional techniques t h a t can be used by vendors d u r i n g f a b r i c a t i o n o r t h a t are a d a p t a b l e t o complex system designs. The s e a l i n g techniques of interest would p r i m a r f l y i n c l u d e l i q u i d hydrocarbon impregn a t i o n methods.

4-3 2 Task 3 . 2 . 4

4.5.8

Joining of molybdenum and molybdenum alloys

‘%he Objective sf this ShabtaSk is to ePPahate existing prOCess@s for joining molybdenum and t~ develop hproved t e c h i q u e s and materials that will facflitate the use of molybdmum or molybdenum alloys i n f u e l processsng systems.

4.5.8.11.

Subtask 3.2.4.1 Development of molybdenum having improved resistance to contagni~ation-~~d~ced enbrittlment and/or

Welded molybdenum j o i n t s are generally brahttle and somewhat f r a g i l e a t te~~peratu~ upe sto 200 to 400’C. This has been attributed t o the K ~ B ~ K I C ~ of c a r b i d e s , oxides and n i t r i d e s , even a t very 1m concentrations. P7-21 Oxygen has been found ts be p a r t i c u l a r l y haPllaful in causing weld cracking because i t apparently f o m s low-melting films w i t h molybdenum that lead to grain b~undargr separation. Recent advances i n melting technology have allowed t h e p~oduetionof very-high-purity base material. However, impurities are g e n e ~ a l b yintroduced d u r i n g welding and studies will be undertaken to e V a l U a t e the effect O f a l l O g . h g dt3IkeIItS Qn rE?dUCklg t h e t@ndenCy for h o t cracking and f o r increasing the room temperature d u c t i l i t y of the ~ e l d ~ ~ ~ nThere t s . is e~idence” t h a t the rare-earth elements and boron m y have beneficial effects, and molybdenum a l l a y s containing these elements w i l l be evaluated initially. Standard weld-cracking tests (e.g., spot Varestrafnt) will be used to evaluate weldability. D u c t i l i t y and toughness Will be HneZiSUPed %8 a ftnnCtkXI Of S t r a i n Kate and tmperatU%@.

.%Subtask 3 . 2 . 4 . 2

Effect of j o h i n g p ~ o ~ e s s eand s variables on welding and mechanical properties

4.5.8.3

Subtask 3 . 2 . 4 . 3

Braze-alloy development studies

k..

4-33 needed i n t h i s area. This a l l o y has s e v e r a l u n d e s i r a b l e c h a r a c t e r i s t i c s which make i t s u s e d i f f i c u l t , such as a tendency t o c r a c k on c o o l i n g a f t e r b r a z i n g and a b r a z i n g temperature t h a t i s above the? r e c r y s t a l l i z a tion temperature of molybdenum. S t u d f e s w i l l i n i t i a l l y emphasize modiffc a t i o n of t h i s a l l o y t o improve t h e s e c h a r a c t e r i s t i c s . However, a more n e a r l y c o r r o s i o n - r e s i s t a n t a l l o y would be d e s i r a b l e and l a t e r s t u d i e s w i l l emphasize development sf an e n t i r e l y new b r a z e material. Braze a l l o y s w i l l be evaluated t o d e t e r n i n e t h e i r w e t t a b f l i t y , f % o w a b i l i t y , mechanical p r o p e r t i e s and c o r r o s i o n r e s i s t a n c e to s a l t mixtures and BI-Li s o l u t i o n s . 4.5.8.4

Subtask 3 . 2 . 4 . 4

Mechanical joint development

The development of mechanical j o i n t s could b e an important f a c t o r i n c o n s t r u c t i n g complex systems w i t h molybdenum. Previous work7 has shown t h a t r e s e a l a b l e mechanical couplings can be made. The o b j e c t i v e of t h i s subtask w i l l be t o extend t h e previous developmental work t o j o i n t s i z e s t h a t would be r e q u i r e d i n e ~ p e ~ i m e n t aand l a c t u a l p r o c e s s equipment. These s t u d i e s would a l s o s e e k t o improve r e l i a b i l i t y and l e a k t i g h t n e s s of couplings. J o i n t d e s i g n and seals are two important f a c t o r s t h a t w i l l be considered.

4.5.9

Task 3.2.5

J o i n i n g of tantalum a l l o y s

The object of this s u b t a s k is to provide joining informtation On specific tantalum a l l o y s s e l e c t e d f o r engineering experiments on f u e l processing. 4.5.9.1

on w e l d b g and mechanical p r o p e r t i e s

.... , :...::a

..... ,*>A ...

Tantalum and tantalum alloys are not generally considered to be difficult to weld. Once a p a r t i c u l a r tantalum alloy is s e l e c t e d f o r a f u e l p r o c e s s i n g a p p l i c a t i o n , i t would be t h e purpose of t h i s s u b t a s k t o review j o i n i n g process methods and d e t e r n i n e optimum p r o c e s s parameters f o r t h e a p p l i cation. The b a s h welding method to be used would b e gas tungsten-arc and t h e v a r i a b l e s t o be optimized would b e h e a t i n p u t , travel speed, welding c u r r e n t and the method of f i l l e r - m e t a l a d d i t i o n . I n a d d i t i o n , t h e e f f e c t of s u r f a c e p r e p a r a t i o n and pre- and post-weld h e a t t r e a t m e n t s w i l l b e determined. Evaluation of weld j o i n t s w i l l c o n s i s t sf p e n e t r a n t examination, helium l e a k tests b e f o r e and after thermal c y c l e s , V a ~ e strafnt tests and d u c t i l i t y and toughness measurements as a f u n c t i o n of s t r a i n rate and temperature.

,&>A...

4.5.9.2

Subtask 3.2.5.2

Brazing development s t u d i e s

If brazed j o h t s are t o be u t i l i z e d w i t h tantalum-base m t e r i a l a i n processing s y s t e m , a braze alloy must be developed. The p r i n c i p a l

4-34 requirements f o r such a n a l l o y would b e c o r r o s i o n r e s i s t a n c e and meshanLeal s t r e n g t h and d u c t i l i t y . Brazing t e m p e r a t u r e would n o t b e as c r i t i c a l as w i t h laaalybdenm because t a n t a l u m a l l o y s do n o t s u f f e r such a s h a r p drop i n d u c t i l i t y upon ~ e c r y s t ~ i l l i ~ a t i I~n ni t.i a l l y , t h e w e t t a b i l i t y and f l o w a b i l i t y c h a r a c t e r i s t i c s of several a l l o y s w i l l b e e v a l u a t e d v i s u a l l y and m e t a l l o g r a p h i c a l l y - A f t e r t h e s e s c r e e n i n g tests, brazed samples dll be exposed to m o l t e n - s a l t m i x t u r e s and Bi-Li s ~ l ~ t i o win s i s o t h e r m a l c a p s u l e tests. The mechanical s t r e n g t h and d u c t i l i t y of the most promising a l l o y s w i l l t h e n be determined as a f u n c t i o n of temperature. F i n a l l y , samples w i l l b e exposed t o m o l t e n - s a l t m h t u and ~ ~ IS%-Li ~ s o l u t i o n s i n flow s y s t e m t h a t s i m u l a t e a c t u a l p r o c e s s i n g c o n d i t i o n s . 4.5.10

Task 3 . 2 . 6

J o i n i n g of g r a p h i t e

One sf t h e requirements f o r t h e u s e of g r a p h i t e i n f u e l p r o c e s s i n g a p p l i c a t i o n s i s t h e development of j o i n i n g t e c h n i q u e s . S e v e r a l t y p e s of j o i n t s i n v o l v i n g g r a p h i t e are a n t i c i p a t e d such as g r a p h i t e - t a - g r a p h i t e and g P a p h i t @ - t o - K e f r a c t o r ~metab. 4.5.lO.l

Subtask 3.2.6.1

Brazing development s t u d i e s

A p r h e d i f f i c u l t y i n braz5ng graphite t o g r a p h i t e and to m e t a l s i s t h e d i f f e r e n c e s in c o e f f i c i e n t of t h e m 1 expansion between t h e g r a p h i t e , t h e b r a z i n g a l l o y s , and t h e metals. I n a d d i t i o n , one Baaeast a l s o c o n s i d e r t h e extreme d i f f i c u l t y i n o b t a i n i n g adequate w e t t i n g and flow. Other requirements are a d e q u a t e s t r e n g t h , s u i t a b l e d u c t i l i t y , and good c o r r o s i o n resistance a

A Eimlted nmber of b r a z i n g a l l o y s have been developed a t ORNL which cont a i n a sufficiemt mount of carbide-foming elements t o a d e q u a t e l y b r a z e g r a p h i t e t o i t s e l f and t o m e t a l . G r a d e d - t r a n s i t i o n j o i n t s have also been developed a t ORHE and t h e s e appear t o be s u i t a b l e f o r o v ~ ~ c ~ m i laatrgg e mtsmatches i n expansion.22 H O W ~ V ~ K none , of t h e b r a z i n g a l l o y s o r t r a n -

s i t i o n joints have been c o r ~ ~ i i ot ens t e d in bismuth-lithium s o l u t i o n s o r m o l t e n - s a l t mixtures, and a development and t e s t i n g p r o g r m w i l l b e Kequired 0

I n i t i a l l y , t h e program w i l l c o n s i s t of c o m p a t i b i l i t y t e s t i n g of t h e existi n g g r a p h i t e - b r a z i n g d l o y s , and, based on t h e s e r e s u l t s , f u r t h e r alloys may be developed. The subsequent b r a z i n g - a l l o y development work w i l l u t i l i z e t h e best-known c o r r o s i o n - r e s i s t a n t materials, and a l l o y s will b e formulated t h a t melt and flow in t h e proper t e m p e r a t u r e r a n g e and which w e t and f l o w ow g r a p h i t e . These a l l o y s w i l l t h e n b e t e s t e d for compatib i l i t y w i t h t h e a p p r o p r i a t e e n v i r o m e n t s ( s e e S e c t i o n 4.4.8, Task 3 . 1 . 4 ) . b

.... ;.;.a -

4-3 5 &

4.5.18.2 ... .&..

.:....

... $jjj

Subtask 3 . 2 . 6 . 2

Organic-cemented joint development

Various cements (such as those containing furfural alcohol), joint designs, and curing techniques have been developed for HTGR applications. The purpose of that work was to obtain cemented carbonaceous joints of the lowestpossible permeability. In the HTGR study it was found that joint thickness must be kept at a minimum, preferably at about 0.020-in. Uniform j o i n t clearances are necessary, and a load of about 280 psi must be applied to the pieces being joined while the cement cures. Strict control over cement preparation must be maintained, and the rate of heating during carbonizing must be carefully controlled. No evaluations of this type of joint have been performed for chemical processing applications, and a compatibility and mechanical property test

program involving sample joints will be conducted. It will consist initially of a review of commercial practices and the construction and evaluation of prototype joints. The evaluation will consist of metallographic examination, leak testing, corrosion testing and determination af hightemperature mechanical properties. 4.5.10.3

Subtask 3 . 2 . 6 . 3

High-temperature diffusion-bonding studies

Solid-state joints of the diffusion-bonding type have been made, but there is considerable difficulty in making engineering components u s i n g this method. Most diffusion bonding applications utilize same deformation QP plastic flow of the base materials during bonding. Two of the most important considerations are joint design and selection of a carbideforming filler metal. A development and evaluation program will be required before suitable procedures can be formulated. Leak tightness, mechanical strength, and corrosion resistance will be determined as a function of time, temperature, pressure, and surface finish with various intermediate filler metals such as tantalum, niobium, and titanium.

4.5.10.4

,..:a

Subtask 3 . 2 . 6 . 4

Mechanical joint studies

The development of high-reliability, leak-tight mechanical joints for attaching graphite to graphite and to metals would be extremely beneficial, and only limited information in this area is available.

An attractive alternate approach is that of combining a mechanical joint with brazing. The mechanical joint would provide additional strength while the braze material would provide leak-tightness. Development work will be carried aut to investigate these possibilities. The work will consist of evaluating existing joint designs for fuel processing engineering systems. Leak tightness will be measured as a function of ternperatuse and thermal cycles. Based on these tests, second generation designs will be developed and evaluated. Key requirements f o r these joints w i l l be reliability (leak-tightness), mechanical strength, and low c o s t .

4-36

4.6

TASK GROUP 3 . 3

CONSTRUCTIQN OF ENGINEERING FUEL PROCESSING

EXPERIMENTS

4.6.1

Objective

4 6 2

schedule

The s c h e d u l e for work i n t h i s task group i s shown in Table 4 . 6 . 2 .

4.6.4

PEac%lities

Facilities a s s p e c i f i e d i n s u b s e c t i o n 4 . 5 . 4 , w i l l b e used i n the development sf materials f a b r i c a t i o n and joining p r o c e s s e s which will b e appbicable t o work i n t h i s t a s k group. 4.6.5

Task 3 . 3 . 1

Continuous F l u o r i n a t o r Experimental Facility

The o b j e c t i v e of this work i s to p r o v i d e and evaluate s u r v e i l l a n c e s p e c i mens f o r a f a c i l i t y i n which continuous frozen-wall f l u o r i n a t o r s will be t e s t e d , and to evaluate t h e e x t e n t to which a f r s z e n - s a l t Payer p r o t e c t s the flUOrlkaaator H l % t e K i d O f cOnStkuCthn (%-nick@l) by d l 0 W h . g paS.SiVat i o n of t h e n i c k e l t o occur. A d e s c r i p t i o n sf t h e facility i s given in Task 2.2.6 (see S e c t i o n a>. 4.6.5.1

Subtask 3.3.1.1

Evaluation of surveiPlanee specimens

Table 4.6.2.

Schedule for wark i n Task Group 3.3 - Construction o f fuel processing experiments Fiscal year

1976

1978

1980

1982

1983

1984

198%

_ _ 1 _

3.3.1

Continuous Fluorinatcar Experimental Facility 3.3.1.1 Evaluation o f surveillance specimens

3.3.2

Fl~ri~tor-Becanstitution Experimental Facility 3.3.2.1 Evaluation of surveillance

specimens 3.3.3

Reductive Extraction P K Q C ~ EFWa c f l i t y 3.3.3.1 Fabrication process procedures and p a r m e t e r s 3.3.3.2 Joining processes and parameters 3.3.3.3 Construction 3.3.3.4 Evaluation of surveillance specimens

3.3.4

M e t a l Transfer Process F a c i l i t y 3.3.4.1 Fabrication process procedures and p a r m e t e r s 3 . 3 . 4 . 2 Joining processes and parameters 3.3.4.3 ConStPUCtiQn 3.3.4.4 Evaluation o f surveillance specimens

3 -3.5

Integrated Process T e s t F a c i l i t y 3.3.5.1 F a b r i c a t b a process procedures and variables 3.3.5.2 Joining processes and parameters 3.3.5.3 Construction 3.3.5.4 Evaluation of sumveillance specimens

-4

Table

4.6.3.

operating

fund

requirements

1975 3.3.1

Cantfnuaus Facility 3.3.1.1 Subtotal

3.3.3

3.3.4

Transfer Process Facility Fabrication process procedures and paraaleters Determination of joinin& precc~ses and parameters Construction Evaluatfan of surveillance specdmens

Subtotal

3.3.4

Integrated 3.3.5.1

Process Testing Facility Fabrication process procedures and variables Joining processes and parameters ccmstruction Evaluation of surveillance specimens 3.3.5

operating

funds

expsrbenta

Fiscal

year

1979

1980

B9SP

1982

10 25 25

60 60

75 75

30 _ 75 75

1983

31984

1985

30 _ 30 30

30 ._ 30 30

10 10

3.3.3

Subtotal

1978

- .-

of proeessbng

aa 10

ExtractLoon Process Facility Fabrication proeeas procedures and parameters Joining processes and panmeters 6hnstruetion Evaluation of mrveillance speeimem

3.3.5.2 3.3.5.3 3.3.5.4

1977

surveillance

Reductive 3.3.3.1

3.3.4.3 3.3.4.4

Total.

3.3.2

Metal 3.3.4.1

1976

- Ganstruction

Experinoental

subtotal

3.3.4.2

3.3.5

Evaluation speciwens

Task Graup 3.3 in 1000 dollars)

3.3.1

3.3.3.2 3.3.3.3 3.3.3.4 Subtotal

Flucrlllator

far (costs

for

Task

6roup

3.3

5 5 5

10 15

10 10

5 5

IQ 10

15 5

20 25

5 5

20 5Q

45 75

1986

4-3 9 4.6.6

Task 3 . 3 . 2

F l u o r i n a t i o n - R e c o n s t i t ~ t i o n Engineering F a c i l i t y

The o b j e c t i v e of t h i s t a s k i s t o provide m t e r f a l s d a t a required f o r t h e construction of a f a c i l i t y i n which a continuous f l u o r i n a t o r and equipment f o r f u e l r e c o n s t i t u t i o n are operated simultaneously, t o provide corrosion s u r v e i l l a n c e s p e c h e n s for exposure in t h e f a c i l i t y , and t o e v a l u a t e t h e e f f e c t of process conditions on eorrosion rate as indicated by t h e specimens and by equipment a f t e r i t s removal from t h e f a c i l i t y . A d e s c r i p t i o n sf t h e f a c i l i t y is given i n Task 2.2.7 (see Section 3 ) . 4.6.6.1

Subtask 3.3.2.1

Evaluation of s u r v e i l l a n c e specimens

Surveillance specimens w i l l be exposed t o conditions c l o s e l y akin t o those expected i n a processing p l a n t . Longer term and more a c c u r a t e c o m p a t i b i l i t y measurements w i l l be made. Weight and/or dimensional changes w i l l be determined. I n a d d i t i o n , metallographic examination, bulk chemical o r s u r f a c e analyses, and mechanical p r o p e r t i e s measurements w i l l be anade on s e l e c t e d samples. In-stream suweillawce s p e e i mens w i l l be ccimpared t o those protected by a frozen-salt l a y e r .

4.6.7

Task 3 . 3 . 3

Reductive Extraction Process F a c i l i t y

The o b j e c t i v e of t h i s work i s t o provide materials d a t a required f o r t h e construction 06 a Reductive Extraction Process F a c i l i t y and t o evaluate t h e e f f e c t of molten s a l t s and BI-Li s o l u t i o n s on materdals p r o p e r t i e s under process conditions.

4.6.7.1

Subtask 3 . 3 . 3 . 1 and parameters

Determination of f a b r i c a t i o n process procedures

A nickel-base a l l o y , g r a p h i t e , and molybdenum have been proposed as materials of construction f o r v a r i o u s portions of t h e f a c i l i t y . The o b j e c t i v e of t h i s t a s k w i l l be t o provide materials a s s i s t a n c e during design of t h e system, which w i l l involve primarily a review of t h e proposed f a b r i c a t i o n procedures. Experimental work on materials w i l l be l i m i t e d t o s p e c i f i c

problem areas t h a t may arise.

4.6.7.2

Subtask 3 . 3 . 3 . 2

Determinatfon of j o i n i n g processes and parameters

The p r i n c i p a l o b j e c t i v e of t h i s t a s k w5ll be t o provfde design a s s i s t a n c e r e l a t i v e t o j o i n i n g methods required for construction of components f o r t h e Reduction Extraction Process F a c i l i t y . Engineering drawings w i l l be reviewed and prototypie j o i n t s made where required.

4-48 4.6.7.3

Subtask 3 . 3 . 3 . 3

Construction

During constmctisn of the Reductive Extrastion Process Facility, mteria%s assistance will be provided as required. Task Group 3.2 w i l l be initiated in IT 1976, and the resulting basellne data w i l l be helpful during construction, particularly if prsblems are encountered. I

4.6.7.3

Subtask 3 . 3 . 3 . 4

Evaluation of surveillance specimens

During operation sf t h e PP, sumeillance s p e c h e n s w i l l be examined p e r i o d i c a l l y to determine the e ~ r ~ ~ s l bbehavior on of construction materials as a funetisn of time under process conditions.

4.6.8

Task 3 . 3 . 4

Netal Transfer Process F a c i l i t y

me objectiv e of tlafs task is to provide =teriais d a t a required f o r construction of a f a c i l i t y for study of the removal of rare eamfths from K B R f u e l carrier s a l t . A description of this facility is given in Task 2.4.3 (see Section 3)

.... <.x<.:

4.6.8.2

Subtask 3 . 3 . 4 . 2 Droeedures

Determination of joining processes and isss.

The purpose of- this subtask is to provide assistance relating to j o i n i n g components for t h e Metal T~ansfelpProcess F a c i l i t y . Engineerhg d e s i g n drawings dll be reviewed and joinhg procedures recomended. Experimental prototype j o i n t s will be constructed, if required. 4.6.8.3

Subtask 3 . 3 . 4 . 3

Construction

terisils assistance will be provided during construction of the Ketal Transfer Process Facility. Design, fabr%eation and j o i n i n g changes wlll be reviewed.

4-41

4.6.8.4

Subtask 3 . 3 . 4 . 4

Evaluation of surveilaanee specimens

Surveillance cOK%.QSiQn SaI’IlpleS Will be f?XlUd@d i F k the Metal Transfer Process F a c i l i t y and t h e s e w i l l be evaluated a t selected t i m e i n t e r v a l s . Samples will be exposed t o a molten f l u o r i d e salt containing rare-earth f l u o r i d e s , B i - L i s o l u t i o n s , L i C 1 , and W-H2 mixtures.

4.6.9

4.6.9.2

,.m

Task 3 . 3 . 5

Integrated Process Test F a c i l i t y

Subtask 3.3.5.2 parmeters

Determination sf joining processes and

Tasks 3 . 2 . 4 , 3 . 2 . 5 , and 3 . 2 . 6 w i l l be aimed a t providing b a s i c information on j o i n i n g ~ P O C ~ S S for ~ S t h e materials s e l e c t e d for construction sf t h e Integrated Process Test F a c i l i t y . Cosrdinatfon of materials and design requirements will be a p r i n c i p a l o b j e c t i v e of t h i s subtask. Prototypic j o i n t csmgponents will be f a b r i c a t e d as required.

4.6.9.3

Subtask 3.3.5.3

Construetion

terials a s s i s t a n c e will be provided as required during construction of t h e I n t e g r a t e d Process T e s t F a c i l i t y . The work w i l l p r i n c i p a l l y c o n s i s t of reviews of design, f a b r i c a t i o n , and j o i n i n g changes. i&...

4.6.9.4

Subtask 3 . 3 . 5 . 4

Evaluation of s u r v e i l l a n c e specimens

Surveillance spech~ensw i l l be ineluded i n t h e I n t e g r a t e d Process T e s t F a c i l i t y and t h e s e w i l l be p e r i o d i c a l l y evaluated during operation of t h e facility. Sfnee t h i s is e s s e n t i a l l y a p i l o t p l a n t f a c i l i t y , most process environments F a l l be encountered under ~ ~ ~ ~ i i t tfhoa tn will s be t f l i c a l Qf actual p l a n t QperatiOla. E

4-42

NCES FOR SECTION 4

Shimstake, N. R. S t a l i c a , and 3 . C. Heason, " C o r r o s $ ~ nof Refractory Metals by Liquid Bismuth, T i n , and Lead a t 1000QC," 2zkz?ts. ANI5 10: 141-142 (June 1967).

R. 6 . Downelly and G. PI. Slaughter, "'The Brazing of Graphite,"

pf.

FeZdizg J. 41(5): 461-69 (1962). 10, J. P. Ilimond and G. M. Salug$~ter, "Bonding Graphite t o Metals with T r a n s i t i o n Pieces FeZd<ng 6. 50 (1) : 33-40 (1970) e

4-43 I

15.

I?.

6. C r o f t , L a m e l l a r Compounds of G r a p h i t e ,

Quart. Revs. Eondun

14: 1-45 (1960). I

6. B. G r i f f i t h and M. W. N a l l e t t , 9. &?.&em. (1953)

Soa. 75: 1832-1834

S a v i t s k i i e t a l . , "Rare E a r t h Alloys," UC-tar-6151.

17.

E. M.

18.

T. P e r r y , I%. S. S p a e i l , and s. Wulff, " E f f e c t of Oxygen on Welding and Brazing Molybdenum," Welding Journal 3 3 ( 9 ) : Research SuppP. 442-s t o 448-s (1954).

19.

W. N. P l a t t e , " I n f l u e n c e of Oxygen on Soundness and D u c t i l i t y of Molybdenum Welds ,I1 Welding Journal 35 (8) : Research S ~ p p l . 369-s t o 381-s (1956).

20.

W. N. P l a t t e , " E f f e c t s of Nitrogen on t h e Soundness and D u c t i l i t y of Welds in Molybdenum," WGZding J o m a Z 3 6 ( 6 ) : Research Suppl. 301-s to 306-s (1957).

2 1*

A. J. Moorhead and 6. M. S l a u g h t e r , "Welding Studies on Arc-Cast Molybdenm," Welding J o m a Z , 1974, t o b e p u b l i s h e d .

22.

J. P . H a m n d and 6. M. S l a u g h t e r , "Bonding G r a p h i t e t o Hetala With T r a n s i t i o n Pieces Weld$ng Journal, January 1971.

5.1

INTRODUCTION

5.1.1

Qbjective

The objective of this activity is to obtain the chemical information necessary f o r the design of molten-salt breeder reactors. Work in this activity w i l l include studies of fuel and coolant salt chenist~egp, measurements of required physical p r o p e r t i e s , studies relating to tritium management, delineation of operating parameters, and chemical studies related to off-design events such as temperature e x c ~ ~ ~ i oOKn s Peaks. T h i s activity will also provide chemical support d u r i n g engineering development activities. 5.1.2

.... ,x<<,

,;.:.. ....... .... 4.

... ....

scope

These laboratory-scale studies w i l l involve detailed investigations of chemistry in W B R fuel s a l t including measurement of solubility products for the actinide oxides, s t u d i e s of the behavior of tellurium under various redox conditions, phase behavior of PUP^^ fue8-eoolanat interactions, and determination of physical property data. Similarly, understanding of the chemistry of the coolant salt NaBP4-MaF (92-8 mole %> must be greatly enhanced. Oxide and hydroxide chemistry in flusroborate w 2 B l receive intensive study along with investigations of the corrosioam chemistry 06 this salt, methods for purifying the salt, and measurements of physical properties. Am assessment of alternate coolants wLl1 also be made. Tritium behavior in MsBR system will also require major study. In addition to measurements of the permeability of various a l l o y s to tritium, the possibility of sustaining an impermeable oxide film on the steam side of t h e steam generator w i l l be fully explored. Measurements of the solubilities, diffusivities, etc. of T2 and HT in fuel and coolant salts will be made to aid in predicting tritium behavior in an system. Studies of fission product chemistry will be focused chiefly on the chemistry of niobium, molybdenum, other noble metals, and iodine. The objective of these studies is the accurate prediction of fission product distribution in an MSBR system. Fmdamental studies of EiP-BeF2ThFq mixtures will include determination of activity coefficients of Both major and minor components of these systems. Porous electrodes w i l l be used to study the chemistry of trace elements such as bismuth bn MSBR fuel salt. Work related to the chemistry of H B R fuel processing is covered in Section 3 Fuel Processing.

.... )...

2!!!!+

.... > :.=

5-1 ....:...... %

5- 2

Schedule and key program milestones

5 2.1 e

me schedule f o r work OB c h e d c a l r e s e ~ c ’ hand development is shown i n

Table 5.2.1.1. The key program milestones for this activity are l i s t e d i n Table 5.2.1.2 and occur at t h e times indicated in T8ble 5.2.1.1.

A summary of the o p e r a t i n g budget i s given in Table 5.2.2.1. 5.2.2.2 shows requirements for c a p i t a l equipment funds.

Table

5 3 . P .Requirements 6

5.3.1.1

Basis f o r fuel salt composition

The fuel s a l t for a single-fluid MSBR must s a t i s f y a number of stringent requirements It must e

(l> have a ]bow capture cross-section for IIEXI~KO~S,

(3)

be thermally s t a b l e

(4)

have a l o w vapor pressure a t 600-75OQC,

(6)

be nanaggressive toward materials of C O I I ~ ~ K U C ~ ~ O ~ ,

(7)

be stable t o reactor radiation,

(8)

tolerate fission p r o d u e t accumulation, and

k.4.

5-3 Very few materials can meet t h e s e requirements. F l u o r i d e s a l t s of 71ithium and b e r y l l i u m are among the few c a n d i d a t e s f o r the molten s a l t . Various compositions of UP4 and ThF4 d i s s o l v e d in mixtures of 'Lip and BeF2 have been c o n s i d e r e d f o r t h e f u e l s a l t . %he most l i k e l y c h o i c e - and t h e p r e s e n t d e s i g n composition - i s LiF-BeP2-ThFq-UPq (71.7-16-62-8.3 mole W > The f u e l s a l t composition has been thoroughly e v a l u a t e d Ln the p a s t and a l t e r n a t e f u e l salts, w i t h t h e e x c e p t i o n of minor a d j u s t m e n t s in camposition o r t h e p o s s i b l e s u b s t i t u t i o n of PuF3 f a r UF4 h c o n v e r t e r r e a c t o r s or f o r MSBR s t a r t u p , are n o t p r e s e n t l y under c o n s i d e r a t i o n .

& .& .

5.3,1.2

Basis f o r c o o l a n t s a l t cornposition

Tke c o o l a n t s a l t , used t o t r a n s f e r heat from t h e f u e l s a l t t o the steamr a i s i n g system, should m e e t a number of requirements and c o n s t r a i n t s 2 which i n c l u d e t h e following:

The consequences of an a c c i d e n t a l mixing of c o o l a n t and f u e l must Primary h e a t exchangers cannot b e guaranteed t o b e l e a k - f r e e f o r t h e l i f e of an MSBR p l a n t ; t h e r e f o r e , t h e r e is a f i n i t e p r o b a b i l i t y t h a t mixing of f u e l s a l t and c o o l a n t w i l l occur. The consequences of such mixing s h o u l d n o t lead t o d i r e consequences (such as n u c l e a r e x c u r s i o n s , chemical e x p l o s i o n s , r a p i d c o r r o s i o n , o r f a i l u r e of major plant components) and must b e r e v e r s i b l e . It is d e s i r a b l e t h a t t h e expensive f u e l s a l t n o t b e rendered u s e l e s s . b e minimal and r e v e r s i b l e .

It would b e h i g h l y b e n e f i c i a l and d e s i r a b l e if v i r t u a l l y all of t h e t r i t i u m d i f f u s i n g i n t o t h e c o o l a n t c i r c u i t w a s s e q u e s t e r e d . T h i s would a i d i n reducing t h e r a t e a t which t r i t i u m t r a n s f e r s t o t h e steam system and mh2mize t h e amount r e l e a s e d t o t h e envir ~ m e n t . Because t h e f u e l s a l t c o n t a i n s a h i g h atomic d e n s i t y of l i t h i u m , a s i g n i f i c a n t q u a n t i t y of t r i t i u m 12420 c u r i e s p e r day i n a ~ B O Q - E I C J ( ~ ) MSBK] i s g e n e r a t e d fn t h e r e a c t o r core.3 S t r u c t u r a l metals b e i n g considered f o r ER%are permeable t o tritiun, and i t i s l i k e l y t h a t a s i g n i f i c a n t f r a c t i o n of t h e t r i t i u m w i l l d i f f u s e i n t o t h e coolant c i r c u i t . .:a

The c o o l a n t must b e compatible w i t h components which i t c o n t a c t s normally. Only m h i m a l c o r r o s i o n of h e a t exchangers, pumps, steam g e n e r a t o r s , reheaters, s t o r a g e tanks, etc., can b e t o l e r a t e d i n normal o p e r a t i o n o r as a r e s u l t of f o r e s e e a b l e l e a k s o r o p e r a t i n g excursions. Small l e a k i n the s t e a m - r a i s i n g system must b e t o l e r a b l e , and n o t Steam l e a k a g e i n t o the c o o l a n t r e s u l t i n s e r i o u s consequences should not r e s u l t i n v i o l e n t reactions with t h e coolant nor render t h e c o o l a n t s e r i o u s l y C O ~ K O S ~ V ~A. p r a c t i c a l means f o r r e p r o c e s s i n g t h e c o o l a n t t o remove water o r i t s r e a c t i o n p r o d u c t s s h o u l d b e a v a i l a b l e . Coolant l e a k s i n t o t h e steam system should n o t Bead t o s e r i o u s c o r r o s i o n such as s t r e s s - c o r r o s i o n cracking. e

Fiscnf

yeaP

_ - --

_”

5-5

T a b l e 5.2.1.2.

Miles t o n e

b c

f 8

3 k

R m

n 0

P 4

r 8

t .:.&

u .... .m ....

v w X

Y z

Key m i l e s t o n e s for MSBR chemical r e s e a r c h and development DeScription

Smary

Table 5.2.2.1.

4.1

Fuel salt

4.2

Coolant

salt

4.3

Trftim

behavior

4.4

Fission

proauct

4.5

Fqndamental

of operating

chemistry chemistry

fund requirements (costs in mxl

of molten

Tot&L operating funds for cherdcal and development

salts research

Sunmary of capital.

Table 5.2.2.2.

research

Fiscal

year

and development

B975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

168

200

146

165

220

345

330

245

110

165

18Q

180

218

220

270

335

360

220

110

105

165

220

270

325

515

55Q

36.5

275

110

165

214

254

250

245

215

140 ---

200

250

200 ---

140

473

710

811

913

1014

a255

l45O

1230

610

fund requirements for work an chemical in 1000 dollars)

research

and developwent

chemistry

studies

for work on chemical aoms-s)

equipnent

1986

-P--P 1014

440

(costs

4.3.

Fuel salt

chedstry

4.2

Coolant

sdt

4.3

Tritium

behavior

4.4

Fission

product.

4.5

~damental

chemtstry

of molten

salts

Tcvtal capital equipment funds for chenaical research ana deve8opment

year

1975

1976

1977

1978

1979

19140

198.l.

1982

1983

1984

145

157

120

5 ----7

1.0

157

273

238

139

chedstry

studies

Ffscal

16 72

--314

251

267

144

11985

1986

5-7

R a d i a t i o n w i t h i n t h e primary heat exchanger should have minimal d e t r i m e n t a l e f f e c t s upon t h e vapor p r e s s u r e , composition and c o m p a t i b i l i t y of t h e c o o l a n t .

The c o o l a n t should have a c c e p t a b l e h e a t - t r a n s f e r and f l u i d p r s p e r ties. Film c o e f f i c i e n t s should b e h i g h ; v i s c o s i t y and d e n s i t y s h o u l d b e low. "he c o o l a n t should have a f r e e z i n g p o i n t below 680°F. h y f r e e z i n g p o i n t below 600 O F (316 "e) would permit feedwater temperatures (558-588"F) used i n c o n v e n t i o n a l s u p e r c r i t i c a l steam c y c l e s . H i g h e r c o o l a n t f r e e z i n g p o i n t s , perhaps as high as 775"F, can b e t o l e r a t e d i f t h e feedwater is p r e h e a t e d w i t h steam d i v e r t e d from the steam g e n e r a t o r s 4 a

The c o o l a n t should e x h i b i t a l o w vapor p r e s s u r e a t normal o p e r a t i n g I f a s i g n i f i c a n t vapor p r e s s u r e (>Q.Ol atm) must b e temperatures. t o l e r a t e d , the vapor should have a l o w condensation temperature. The coolant shouPd b e i n e x p e n s i v e and a v a i l a b l e in high p u r i t y . Elements rare i n the e a r t h ' s c r u s t should n o t b e considered f o r a f u t u r e m u l t i r e a c t o r MSBR system. Only a few materials m e e t these requirements and c o n s t r a i n t s . The p r e s e n t d e s i g n composition is a mixture of 92 mole X NaBF4 ( s o d i m f l u s r o b o r a t e ) and 8 mole X NaF. The f l u o r o b o r a t e c o o l a n t does n o t completely s a t i s f y a l l o f t h e above criteria, although its shortcomings can b e accommodated by design adjustments. Alternate c o o l a n t s are a l s o b e i n g considered Task 4.2.4). S h c e some u n c e r t a i n t y e x i s t s as t o t h e (Sect. 5.5.8, u l t i m a t e c h o i c e of c o o l a n t , t h e coobant s a l t r e s e a r c h and development a c t i v i t i e s are n o t as firmly d e f i ~ e das t h o s e f o r t h e f u e l s a l t . 5.3.2 5.3.2.1

Background Experience w i t h rnolten s a l t f u e l s

Molten salt systems f o r high-temperature I I U C ~ ~ r~eKa c t o r s have been under development since 1947 and e x t e n s i v e e x p e r i e n c e w i t h fluoride-based salts h a s been accumulated. F i r s t developed were NaF-ZrF4-UF4 mixtures which f u e l e d t h e A i r c r a f t Reactor Experiment i n 1954. As b r e e d e r r e a c t o r development r e c e i v e d i n c r e a s i n g emphasis, a fuel composed of 7LiF-BeF2ZrFb-UFb was developed a n d used i n the Molten-Salt Reactor Experiment (MSRE) which o p e r a t e d f o r a t o t a l of 2-1/22 y e a r s beginning i n 1966 u n t i l t h e scheduled s h u t down. E x t e n s i v e experience w i t h f l u o r i d e - b a s e d molten s a l t s w a s accumulated during t h i s period.6 Thus, t h e p r e s e n t f u e l s a l t s e l e c t e d f o r M S B b is based on a long, w e l l - e s t a b l i s h e d background sf e x p e r i e n c e and a p p e a r s most l i k e l y t o met the requirements of N S B b w i t h a m i n i m u m of a d d i t i o n a l r e s e a r c h and development.

5-8

5.3.2.2 I

5.3.3

status of development

5.3.3.1

Fuel s a l t chemistrx

Phase equfllbria among the p e r t i n e n t MSBR f l u o r i d e s l a r g e l y have been studied in detail, and the equilibrium diagrams are relatively w e l l understood. Diagrams for b i n a r s y s t m s such as LiF-BeF2, EiF-WL&, and LIF-TKF4 have been developed; 9 similarly, those for ternary s stems such as EiB-BeF2-rnF4 and kiF-BeF2-rnq have been establfshed 9 e

5-9 I

~n t h e presence s f oxide are r e q u i r e d . I f a c c i d e n t a l contamination of MSBR f u e l w i t h s i g n i f i c a n t ~ o u n t sof a i r water s h o u l d occur, t h e n n o t o n l y could UO2 p r e c i p i t a t e b u t also I%O2, Ba02, PuO2 and Np02. It has been e s t a b l i s h e d that the a c t i n i d e d i o x i d e s a l l have t h e same f l u o r i t e t y p e s t r u c t u r e ; ~ ~ n s e q p a e n t l yt ,h e p r e s e n c e of ms OK more a c t i n i d e s i s conducive to t h e formation of i n s o l u b l e oxide solict solutisns. 13-16 The d a t a o b t a i n e d i n d i c a t e d t h a t t h e d i s t r i b u t i o n of h e a v i e r a c t i n i d e s between the l i q u i d and s o l i d phases s t r o n g l y f a v o r s t h e latter. A ~ o r r e l a t i s nwas fsurnd between t h e measured d i s t r i b u t i o n q u o t i e n t s and the l a t t i c e parameters of t h e pure a c t i n i d e o x i d e s which allowed preclfction o f t h e p r e c i p i t a t i o n b e h a v i o r of neptuniumE6 arad t h e d i s t r i b u t i o n 0% a c t i n i d e s between the m e l t and b i n a r y and t e r n a r y solid s o ~ u t i o n s'1.

..u

The i m p o r t a n t effect of t h e redox p o t e n t i a l of t h e f u e l OR t h e ~ o ~ r o s i ~ l t a of s t r u c t u r a l materials in a molten-salt r e a c t o r has a l s o been recogn i z e d . 18 ~ r o man o v e r a l l s t a n d p o i n t s t h e f i s s i o n process i s s l i g h t l y by u s i n g a redox b u f f e r o x i d i z i n g ; t h i s e f f e c t w a s m i t i g a t e d i n t h e MS e s t a b l i s h e d by m a i n t a i n i n g a s m a l l f r a c t i o n of the uranium p ~ e s e n tas UP3. "he UF3/UFb ratio thus e s t a b l i s h e d t h e redox p o t e n t i a l of the f u e l s a l t . All of t h e a c t i n i d e s p r e s e n t i n s i g n i f i c a n t q u a n t i t i e s i n an MSBR, w i t h t h e e x c e p t i o n of t h o r i m , e x h i b i t a m u l t i v a l e n t character; t h u s , the redox p o t e n t i a l of t h e fuel w i l l determine t h e o x i d a t i o n s t a t e of these elements and, consequently, t h e v a l e n c e of t h e a c t i n i d e s i n a p r e c i p i t a t e d o x i d e phase. E t has been determined t h a t t h e s o l u b i l i t y b e h a v i o r sf t h e p r o t a c t i n i u m o x i d e s Pa205 and Pa02 is q u i t e d i f f e r e n t . The former appears as a s i n g l e phase and h a s a much lower s o l u b i l i t y t h a n Ba02> w h i c h a p p e a r s in binary o r t e r g i a r y s o l i d s o P ~ t i o n s . ' ~ 9 ~ ~ S i ~ ~ d l a ~ l ig tr ,has been demonstrated t h a t plutonium w i l l p r e c i p i t a t e only as a d i o x i d e i n s o l i d s o l u t i o n while t r i v a l e n t plutonium does not appear t o p r e c i p i t a t e a t a l l as m o x i d e from the f u e l salt,15 Prom the s t a n d p o i n t of r e a c t o r s a f e t y , i t is very i q m r t a ~ t o e v a l u a t e a c c u r a t e l y the s o l u b i l i t y b e h a v i o r of t h e v a r i o u s a c t i n i d e oxides and ~ e as a f u n c t i o n sf t h e i r i n t e r a c t i o n s as a function of ~ e m p e r c ~ t uand redox pscential. some actinide o x i d e f l u o r i d e systems have been w e l l characterized w i t h regard t o t h e i r pendence on temperature a d redox p o t e n t i a l w h i l e o t h e r s are less w e l l defineci; thus, t h e r e s e a r c h r e q u i r e d on t h i s s u b j e c t ( d i s c u s s e d i n d e t a i l later) h a s v a r i o u s degrees of priority e

... ....

After shutdown of t h e MSRE, i t w a s found t h a t some i n t e r g r a n u l a r a t t a c k had ~ C C U K I X X ~in ~ a s t e ~ oN ysamples and r e a c t o r components.21 ~ l t h o u g ~ ~ the attack w a s not c a t a s t r o p h i c , i t appeared to be s i g n i f i c a n t when t h e s p e c i ~ were ~ ~ s subjected t o stress. Analyses of the specimens i n d i c a t e d the p r e s e n c e of f i s s i o n p r o d u c t s , esgeegally t e l l u r i u m . Pre1imbax-y seaming t e s t s made i n the laboratory w i t h several of these elements s u g g e s t e d s t r o n g l y that t e l l u r i u m w a s r e s p o n s i b l e f o r the i n t e r g r a n u l a r L i t t l e is known about t h e b e h a s r i ~sf ~ t e l P u r i w n i n an MSR envkomnent, e s p e c i a l l y about the effect of the redox p o t e n t i a l of t h e f u e l on t h e relative c o n c e n t r a t i o n s of t h e V ~ K ~ O U StePBurium s p e c i e s

5-10 I

~ e 2 ,~ e ~ etc. - , W U C ~ may be ~t i s necessary to study t h i s e f f e c t in order t o develop methods f o r d e a l i n g w i t h the presence of telluKim e

P l u t o n i m (as PuF3) has been proposed as a component of the s t a r t - u p fuel f o r I J E B R S ~ ~ o r as the make-up fuel in molten-salt converter r e a c t o r s ; i t has a l r e a d y been used as f i s s i o n a b l e make-up f u e l , r e p l a c i n g the eonsmed t n the NSRE.~ IW order t o s t a r t up a molten-salt r e a c t o r with p ~ u t o n i m and run i t suecessf~nlly,tbe b e h i o r of tHs element under n o m a 1 o p s r a t h g c o n d i t i o n s and in the presence of i m p u r i t i e s such as 02- has to be h o r n . The s o l u b i l i t y of PUFQ in molten f l u o r f d e s mst be adequate t o s a t % s f y t h e requirements of converter or breeder r e a c t o r s . some s o h b f l i t y measurements i n LiF-BeF2-TM4 s o l u t i o n s were made a t 2 4 ana at Bhabba Atomic R e s e a ~ c hCentre, India.25 Although there is a discrepancy between t h e values obtained by the l & o ~ a t o r i e s , the r e s u l t s obtained i n d i c a t e that even t h e lower measured s o l u b i l i t i e s (India) amply s a t i s f y the r e q u i r a e n t s f o r ibfl MSBR. Nevertheless, it 1s necessary to deternine the cause 0% t h e diffe-mrence i n the values. me effect of oxide on t h e s o l u b i l i t y of BuFg under different redox c o n d i t i o n s has been studFed t o sone .extent at 0 but m o ~ er e s e a r c h w S B l b e r e q ~ i ~ e d Order to COIIlpletdy define the S y S t a and t Q Obtain P l s e f U l themechemical. data for t h e various plutonium s p e c i e s .

ABthough physical r o p e r t i e s of f l u o r i d e mixtures are, i n general q u i t e w e l l known, 2’s29 t h u s e of the MSBR fuel s a l t in p a r t i c u l a r w i l l requ5z-e p r e c i s e measurements, especially i t s thermal c o n d u c t i v i t y . The vapor pressures the predominant s p e c i e s in t h e vapor phase above the residual fuel s a l t after vaporizatfon of a s p e c i f i e d f r a c t i o n of the initial l i q u i d , and the latent heat of v a p o r i z a t i o n of the eorregponding l i q u i d will have t o be determined s i n c e no d i r e c t measurements are c u r r e n t l y a v a i l a b l e ; t h e p r e s e n t estimates were obtained by e x t r a p o l a t i o n from measurments with the systems LiF-BeF2 and LfF-BT1p4. A uP,/mb ratio w i l l have t o be selected f o r t h e WBR which satisfies o r reaches a comprmise among t h e numerous e q u i l i b r i a occurring simultaneously i n the r e a c t o r ; e . g . the d e p l e t i o n of chrmim from t h e s u r f a c e of the BastelBsy N, the oxidation-reduction of tellurium s p e c i e s and sf protaethium 4-k and 5+ s p e c i e s , the r e a c t i o n of UF3 with g r a p h i t e l e a d i n g

w..

45-11 to t h e formation of uranium carbides, etc. The 1atte.a: equilaibrim has been studied,30 and the r e s u l t s fndicated t h a t f u e l s a l t with a UF4/W3 r a t i o l a r g e r than 10 i s s t a b l e a t 550'6 w5th respect t o t h e fornation of t h e uranium carbide UC2. I n the event of atmospheric contamination, not only does t h e UF~/UFL,r a t i o decrease but t h e concentratton sf Q2" increases. Evidence has been found r e c e n t l y which suggests t h a t t h e presence of oxide may lead t o the formation of s o l i d uranium oxycarbides, nore stable than the h i n a r y cargide.30 Since no other d a t a on the s u b j e c t are a v a i l a b l e , t h i s aspect of the e f f e c t of a i d e and redox p o t e n t i a l will be =mined f u r t h e r .

5.3.3.2

Coolant s a l t chemistry

In an blf%B it i s mot p o s s i b l e t o couple the c i r c u l a t i n g f u e l d i r e c t l y to t h e steam-generating system. Two reasons may be cited: f i r s t , t h e m e l t ing p o i n t of t h e f u e l s a l t 1s considerably higher than t h e feedwater temperatures d e s i r e d f o r t h e steam system; second, l e a k s would have undesirable economic and p o t e n t i a l l y hazardous consequences; e . g . , stem leaking i n t o t h e f u e l salt would p r e c i p i t a t e uranium, t h o r i m , and beryllium as oxides and f u e l leaking i n t o t h e stem system would c o n t m i nate t h e l a t t e r with f i s s i o n products, tritium, and o t h e r r a d i o a c t i v e substances (Pa, U, Th). Thus, an MSBR r e q u i r e s a coolant system to act as a p r o t e c t i v e b a r r i e r between t h e f u e l c i r c u i t and t h e steam-generating system and t o t r a n s p o r t t h e h e a t t o the s t e m - r a i s i n g system without f r e e z i n g e i t h e r fuel s a l t o r c001ant. Coolants being considered f o r o t h e r advanced r e a c t o r s are less d e s i r a b l e as coolants f o r molten-salt r e a c t o r s . S o d i m (as w e l l as o t h e r alkali metals) reacts vigorously ~ 5 t hf u e l s a l t and with stem. High-pressure helium would r e q u i r e that the p r h a r y heat-exchanger system be very large, thereby increasing t h e f u e l inventory and the'doubling t h e of the reactor.

.:&

,+a

... ..... .x.:,J

1x1 the MSRE, the coolant was 7 L i P - BeF2 (66-34 mole X ) ThLs eoolant discharged i t s heat a t 546'C (10%5'??) to an air-cooled r a d i a t o r which was maintained above the c o o l a n t ' s f r e e z i n g p o i n t , 459°C. The WRE coolant composition is not s u i t a b l e f o r use i n an MSBR s i n c e t h e f r e e z i n g p o i n t is too high for t r a n s m i t t i n g h e a t t o a system i n which t h e feedwater i s supplied a t o r below 371BC (700°F). I n addition, t h e r e would be a p r a c t i c a l n e c e s s i t y f o r using i s o t o p i c a l l y pure (and expensive) l i t h i m - 7 i n t h e coolant s a l t . If lithium i n n a t u r a l i s o t o p i c abundance w e r e used, l e a b g e of coolant i n t o the f u e l c i r c u i t would r e q u i r e expensive procedures f o r removing l i t h i u m 4 0'1: acceptance of decreased breeding performance and increased tritium production.

There are twc important requirements f o r an MSBR coolant. One, which is unique and s t r i n g e n t , is t h a t the e f f e c t s of leakage i n t h e primary h e a t exchanger must be minimal and r e v e r s f b l e . It i s a l s o highly d e s i r a b l e that a l l t h e t r i t i u m t h a t d i f f u s e s f n t o t h e coolant circuft be sequestered i n t h i s c i r c u i t . The f i r s t requirement dictates t h a t chemical r e a c t i o n s between t h e f u e l s a l t and t h e coolant must not lead to p r e c i p i t a t i o n

I I I I

5-12

A molten E L ~ X ~ Uof K ~NaBF4 a d NaF provisisnally appears to m e e t the necessary heat-transfer requirements for a n MSBR C Q O ~ ~ I I ~ It , i s relatively inexpensive and, at normal operating temperatures ( 4 5 4 62l"e>, exhibits a c c e p t a b l e thermal mpacity, 28 thema1 ~ ~ ~ d u c t i v 32 i t yand , f a v o r a b l e viscosity and density.29 The vapor pressu~eof BF3p due to t31erml decomposition of t h i s coolant, w a s found to be less than l atm at the highest o p e r a t i n g temperature for compositions contaiming less than 9 3 mole NaBF4. Accurate studies of phase behavior28 showed t h a t the composition NaBF4-NaF (92-8 m l e had the lowest-melting p o i n t , 384"@, in t h e system,

.... l .I .. .....

.... .....

K<.X>

5-13 5 3.3.3

T r i t i u m behavior

In addition t o the loss of t r i t i u m t o the environment, contamination of the steam system could reach levels of 4-9 m W c e i n the 300,000-gaI inventory of water i n a t y p i c a l p l a n t S7 his concentration is about t h e same as i n t h e m o d e ~ a t o rof a large heavy w a t e r reactor,39 and ext e n s i v e s a f e t y precautions would be required t o permit maintenance sf the MSBR steam system. Tritium t r a n s p o r t t o the s t e m system m i t b e prevented i f a C o d h a t i o n of techniques can b e used t o contai andl t o process the tritium in a MSBR. Containment m i g h t be achieved if, f o r example, an oxide C ~ ~ K S S film ~ O ~f o m e d by s t e m on steam g e ~ l e r a t ~ tubing r serves t o ede tritium perneation. Some v a r i e t i e s of corrosion films on candidate s t e m genera to^ materials have been f s m d t o o f f e r significant iIlTpedastC€? t O pelXleat~On.40 The E?Xten%%Oll Of t h i s WQJrk t C 3 the CCKLd%tiO%lS expected in a steam generator w i l l r e q u i r e experimental development.

... .... ,&

.. ..... ,.:.=

<>&

... . a

Both the chmical f o m and t h e t r a s p o r t p r o p e r t i e s of tritium are s i g n i f i c a n t f o r c o n s i d e r a t i o n of tritium management i n MSBR systems. S s l u b i l i t i e s and d i f f u s i v i t i e s of t r i t i u w c o n t a i n i n g s p e c i e s i n fuel and coolant are needed f o r t h e development of adequate r e p r e s e n t a t i o n s of tritium behavior in S B W s and f o r e v a l u a t i o n of p o t e n t i a l methods f o r tritium process2ng. Some measurements sf h drogen and deuterium solub i l i t i e s in fluoride salts have been made.4Y The r e a c t i o n of hydrogen with uranium (EV) f l u o r i d e t o produce U F g and hydrogen f l u o r i d e has been s t u d i e d , 4 2 as has t h e adsorption of hydrogen on graphite.43 The sherdeal ~eactalonsof hydrogen w i t h candidate coolants have also recalved a t t e n t i o n . It is p o s s i b l e t h a t a chemical p ~ o c e ~ s i ~ method lg %or removal of tritium f r o m t h e eoslant may b e developed. Such development w s d d require a d d i t i ~ n dresearefa m d wc~uldnot obviate the need for an increased r e s i s t a n c e t o tritium perneation which may be afforded by a c o r r o s i o n f i l m in t h e steam generator.

5-14 1

5.3.3.4

Because of the effect of fission products on reactor operation and performance d t h regard t~ breedimg, materials behavior, afterheat and maintenance, much attention bas been given to understanding their fate the m u ana m r e ~ 1 sece%sariiy 1 be in h t r a r e velopmerat. The fission products fall f n t o several groups according to their chemical behavior 2n molten fluorides. These groupsI fn order sf importance as neutron poisons, are: the noble gases, the stable saltseeking rare-eartb fluorides, the noble metals, and the other s t a b l e salt-seekimg fluorides. Table 5 . 3 . 3 . 4 shows the distxtbution of fission produets found in the MSm. The noble gases have very low solubilities in the fuel saltb19 4 2 - 4 6 and, ConseqUently, Can be PmOVed by SpaXgqfEg Wfth h d % m . miS Was effectively d a o n s t r a t e d in the Msm where mer 80% of the 535xe was r a o v e c f a 4 7 More efficient methods of spargiwg have been proposed for the MSBR and, consequently, noble gas poisoning is expected to be held at a minimum. Since most of the 135x3, is produced indirectly by decay Of the 6.7-hr t m ~ f - l i f eE3%, the usage sf sidestream i o d i n e strippers has been suggested76 as a method of minimizing poisoning in an MSBR. mis would inVOlV@ the reaction: Hp&) 1-!- HI(g), Where m(g> is added in mall m o u n t s to the nsmal helium sparge. If the other methods for h o l d i n g the 13%e poison fraction48 at acceptable levels do not prove successful, it has been proposed that t h e iodine stripping system might be used in esnjunctPon with the Xe removal process. -f

rare earths and other stabbe soluble fluorides ( e . g . , ZP, Ce, Nd, SK, CS, P, Ea, Rb) are d l a p e c t e d to be found p3?kIcipally h the fuel s a l t and can be removed by processing schemes currently under development (see Section 3 ) . The chemical behavior of the above fission products is fairly w e l l understood and, like the noble gas behavior, can be anticipated in operating molten-salt reactors.

me chemical behavior of the so-called noble-metal fission products p MO, Tc, Ru, Sb, and Te) is considerably less predictable - as has been borne out in MSrn operations - and warrants further study. These fission products appear throughout the fuel system: in the salt, metal, graphite and, possibly, the cover gas (Table 1). Baaed can availa b l e tbemodpmic data, they are expected to appear in a reduced form at mq/wq P a t i O S less' than 1 0 ' . &3W€?WXt ill the kedUced and preSUDI@d metallic state, these fission products can d i s p e r s e via many mechanisms.

~m operation analyses of f i v e noble-metal nuclides

9 g ~ o 10 ~ R U , les ranged from fractions to tens of percent of inventory. Based on thermodynamic considerations and a correlation of their behavior with t h a t of for which no stable fluoride exists under fuel salt conditions, it has tentatively been concluded that they are also metallic species which occur as finely divided particles suspended in the s a l t . 06RU, 129-E3%eS found in salt s

u..,

Table Fission

5.3.3.4.

Indicated

&ample

isotopes

95Zr,

144Ce,

llb7Nd

Stable salt seekers (noble gas precursors)

8gSr,

137&,

140&,

Noble

gases

Noble

metals

g5Nb,

ggMo,

91y

106Ru,

lllAg,

12gTe

P31I 9 1351

IOdh& %or example, b Particulate c? Substantial

fission

products

In salt seekers

salt

in molten

salt

Distribution

product g-v

Stable

distribution

Zr tends

to aesumuhke

with

observations

suggest

appreeisble

iodine

be removed

cadd

Pa holdup

(%>

To metal

TQ graphite

To off-gas

Other

v39

Negligfble

NegPigible

Processinga

Variable/T1/2 af gas

Negligible

Low

VariabBe/Tp/z of gas

Negligible

Low

MwdTl/Z gas

B-20

5-30

Negligible

Processingb

50-75

<I.

Negligible

Processing"

in reductive

percenkages

side-skresm

reactors

stripping

will

extraekion

(fission recoils)

processing.

appear

in processing

is used

to remove

streams. ls51

[77].

5-16 B

as smples t a b n from the pump bowl during 2 3 5 ~operation of the MRE indicated that s u b s t a n t i a l concentrations of noble metals w e r e present 5I-I the gas phase, but b p r w e d sampling techn2qaaes fncorpOTated denraEng the 23% operation sf the MS failed to c o n o b o r a t e these observations Present interpretations of t se conflicting data est that the earlier 2 3 % - o p e r a t ~ o n samples w e r e contantn5nated by s a l t mist, and that only a small fraction of the noble metal fissfon produets escape to the cover gas.

The actual state sf these noble metal fission products is sf b p o r t a n c e to the effectiveness of BR operations. If they exist as metals and plate the Mastelloy N po i o n s of the reactorg they w i l l be of l i t t l e consequence as poisons although they can be of h p o r t a n c e in d e t e m i n f n the level of f i s s i product afterheat a f t e r reactor shutdown and wFll cmplicate maintew ce operations and post-operation decontm5nation. (me effect of Te on structural metal i n t e g r i t y is a l s o realized here but is treated in Section 5 . 4 . 6 ) . They can potentfally cause d i f f i c u l t y by carbide fornation or by adhering 5n some other way to the graphite moderator; howevero lsiaIIlination of the MS graphite moderator indicated that the extent of such deposition was 1imPted.

5-17

metal fission products or to control t h g i ~deposition could be an attractive ~ e s d of t such studies. F i n a l l y , future work should take into account handling of the noble m e t a l s o r structural components c o n t d n a t e d by them. 5.3.3.5

Fundamental studies of molten salts

f A fairly comprehensive knowledge of the f o r m t i o n free energies (AG 1 of solutes in molten Li2BePq has been gained over the years from measurements of heterogeneous equilibria involvin V ~ P ~ O Ugases S ( e . g . , HP or HZQ) and s o l i d s ( e . & , metals or oxides). 4g-54 The list of dissolved cowonents f o r which f o r m t i o n free energies have been estimated irad u d e s L f P , BeF2, %Fb,, several KaKe-earth t r i f l u o r i d e s , ZKF4$ m3, UF4, PaF4, PaF5, PUP3$ CrP2, FeF2, MiF29 mPqS NbFg, MoPcJ9 HF, BeO, BeS, Be(OH12, and BeIze some of these a d values, however, are presently insufficiently accurate f o r the needs of the TBBR program (e.g., those for PaP4, PaP5, ThF4, MoP3, NbPq, NbF5, BeS) and additional equilibrium measurements involving these solutes are needed. M ~ P ~ Q v ~there T , is a need f o r the 86:f values of certain other f i s s i o n product compounds suck s compounds of as the lower f l u o r i d e s of T c and Ru, and v a ~ i o ~dissolved ~ needl is an increased knowledge of how a c t i v i t y coeffiTe. A I B B T urgent cients ( t . a i c ~have been defined50 9 51 as unity in L I ~ B ~ Pvary ~ ) as the melt composition changes. such b o w l e d g e is required to predict %SOW the nmerous s h e d e a l equilibrium constants that may be derived from bGf values in ILi2BePq d.11 change as the melt composition is changed to that of an %BR f u e l . Et is clear from what is h o r n that the variation of activity coefficients with melt composition depends primarily on the mle fraction of EiP and the size and the charge of the cation involved. Enough additional data reElecting the variation of a c t i v i t y csefficien~s with melt composition is needed to make this c ~ r r e h t i o nsufficiently quantitative to me% the needs of the MSBR program. ~ o r o u sOK packed-bed electrodes have been demnstrated to lxxve excellent capability for removal or measurement of species at low concentration in aqueous media. 55 3 56 Application of suitable inpressed electrochemical potentials to such electrodes r e s u l t s in quantitative deposition of the species of interest. FrelFdnar~grconsiderations suggest the successful development of techniques for utilizing s i d l a r e.beetrodes in fused salts

of interest to ~ ~ ~ P t e n - sbreeder dt reactsms. Successful development of such techniques could lead to analytical a d process applications for detecting and/or r e m v h g various chemical species such as oxide, tellurim, or bismuth at the parts per million level.

5 4 . I Obj eetive

5-18 E

some aspects need f u r t h e r research t o determine the v a r i a b l e s which d l 8 allow the reaetsr t o o p e r a t e under o p t h conditions. The s t u d i e s c ~ ~ e r ei nd t h i s task group, with t h e a c ~ e p t i o nof t h e determination of s m e p h y s i c a l p r o p e r t i e s , lean heavily toward safety a s p e c t s of the r e a c t o r p ranging from n~kl~lla% operating conditions t o accidental c o n t a i n a t i o n with the atmosphere m d a c c i d e n t a l mixing of fuel and c ~ o l a n t . These o b j e c t i v e s are discussed below as tasks and subtasks and are itemized 5n t h e schedule (Section 5 . 4 . 2 ) .

The schedule for t h i s t a s k group i s shown i n Table 5.4.2.

5 4 3 e

Funding

Anticipated funding requirements are shorn in Tables 5.4.3.1 for aperating and c a p i t a l funds, r e s p e c t i v e l y .

5.4.4

and 5.4.3.2

Facilities

The research i n t h i s task group can be c a r r i e d out i n e x i s t h g chemical l a b o r a t o r i e s i~ Building 4500s and the High-Lwel Alpha Laboratory i n Building 4581. Ns a d d i t i o n a l s p e c i a l f a e f l f t i e s will be needed. 5.4.5

Task 4.1.1

Solubility products of a c t i n i d e oxides

The presence of oxide i s m i n f u e l s a l t above some level has a d e l e t e r i o u s e f f e c t because i t acts as a p r e c i p i t a t i n g agent f o r t h e actinide ions. Because several actinides w i l l be S ~ U ~ ~ E H X X X IpSr e~s~e n t im the fuel s a l t , i t i s d e s i r a b l e t o have a c c u r a t e measurements of the s o l u b i l i t y PrQdUCtS Sf the pure oXfd@s over the Pan@? of redox potential Values Q f i n t e r e s t for molten salt reactors. T h i s , in t u r n , w i l l allow caPculatisn of the s o l u b i l i t y and csmpssition of mixed oxides i n solid s o l u t i o n . Although t h o ~ i moxide exhibits the h i g h e s t s o l u b i l i t y among t h e a c t i n i d e dioxides, t h s r i m i s by f a r the m o s t abundant a c t i n i d e p r e s e n t i n t h e reactor and, thus, its oxide call Bower the a c t i v i t y (by S o l i d ScBluthn formation) of o t h e r a c t i n i d e oxides. Additional studies are required on t h e s o l u b i l i t i e s of oxides sf thorium, protactinium, plutonium and neptunium i n fuel salt. It i s not believed t h a t d a t a are required f o r oxides of higher atomic number than plutonium s i n c e t h o s e elements w i l l be p r e s e n t a t very low concentrations.

5.4.5.1

Subtask 4.1.1.1

TBloriEHllE oxide

The s s h b i l i t y product of Tho2 in molten ~ l a h t u ~ eofs LiF-BeF2-1FPsFq has been detemfned i n d i r e c t l y from e q u i l i b r a t i o n s t u d i e s wfth o t h e r a c t i n i d e

Table 5.4.2.

Schedule for work in Task Group 4.X - Puel salt Fiscal

4.1.1

Solubility oxides 4.1.1.1 4.1.1.2 4.1.1.3 4.1.1.4

products

of actinide

Thorium oxide Protactinium oxides Plutonium oxides Neptunium oxides

4.1.2

Tellurium chemistry 4.1.2.1 Solubility of tellurium and tellurides in molten solvent salts 4.1.2.2 Behavior of Teg" in the presence of metals of construction 4.1.2.3 Oxidation-reduction chemistry of tellurium in fuel salt containing uranium 4.1.2.4 Preparatian of metallurgkal samples

4.1.3

Phase behavior saat

4.1.4

Fuel-coolant interaction studies 4.1.4.1 Phase equilibria 4.1.4.2 Dynamic investigations

of PuF3 in fuel

year

chemistry

Table 5.4.2

(continued) Fliseal. yeas

--.

Table 5.4.3.1.

Operating

fund requirments of Task Group 4.1 - Fuel salt (costs in 1QOQdollars) Fiscal

4.1.1

Solubility prsducts of actinide oxides 4.1.1.1 Thorium oxide 4.1.1.2 Fhotactinium oxides 4.1.1.3 P$utonim oxides 4.1.1.4 Neptunium axides Subtotal

4.1.2

Subtotal 4.1.3

Phase behavior salt

4.1.2

of Pulp3 in fuel

year

55 25

25 80

110

-Pm

110

15 65

15 70

15 $5

15 70

4.1.1

Telluriun~ chemistry 4.1.2.1 Sohbility of tellurium and tdlurides in molten solvent salts 4.1.2.2 Behavior of Tegll- in the presence of metals of coQ%&ruction 4.1.2.3 Oxidation-reduction chemistry of tellllurium in fuel salt containing uranium 4.1.2.4 Preparation of metallurgical samples

chemistry

25 65

15 75

15 91

55 55

55 110

125

Table 5.4a3.1

----....

4.1.4

Fuel-coolant iateraetion studies 4.1.4.1 Phase equilibria 4.1.4.2 Dynam¶.s fnvestigations Subtatal

4.1.5

1975

1976

1977

1978

40 3Q 70

28 28

20 20

1979

Fiscal

year

1'98Q

1981

1982

1983

5.5 55

__ XL6

PhyslsaP property determinations QQ fuel salt Thermal conductivity 4.1.5.1 Surface prapertiea 4.1.5.2 4.1.5.3 Vapor pressure, ccmpositian, and heat of vaporization Subtotal

4 * 1 B6

4.1.4

(eontimed)

4.1.5

U3+/U4+ equilibria

studies

Total operating fund requirements Task Group 4.1

for

55 -~

55 -----

25 ----

168

200

166

165

220

345

330

1984

1985

55 ___ 110

55 55

245

110

1986

Table

5.4.3.2.

Capital

equipment

fund requhements for Task Croup 4.1 - Fuel salt (costs in lOQO dollars) Fiscal 1975

4.1.1

4.1.2

Solubility oxides 4.1.1.1 4.1.1.2 4.1.X.3 4.1.1.4

Thorium oxide Protactinium otides Plutonium oxides Neptunium oxides

Subtotal

4.1.1

Tellurium 4.1-2.1

chemistry Solubility of. tellurium and tellurium in'molten solvent saii.ts Behavior of Te3'" in the presence of metals of construction Qxidation-reduction chemistry of tellurium in fuel salt containing uranium Preparation of meta1lurgica.l EWlpl@s

16.1.2.2 4.1.2.3 4.1.2.4 Subtotal 4.1.3

products

1977

1978

1979

year

1980

1981

1982

1983

1984

1985

of actinide

4.1.2

Phase behavior

1976

chemistry

of PuF3 in fuel

salt

5 47

10 5 15

10 10

5 2

Table

5.4.3.2

(continued) Fiscal

1975 4.1.4

Fuel-coohmt interactim 4.1.4.1 Phase equilibria 4.1.4.2

Subt6)td. 4.1.5

Dynamic

1976

1977

1978

1979

year

198Q

5 5

4.1.4

Physical property detetminstiom fuel salt mema conductivitv 4.1.5.1 Surface properties 4.1.5.2 4.P.5.3 Vapor pressure and composition

Total

capital

Group 4.1.

equipment

studies --_

tunds

1982

1983

ae, 50

60 65

20 20

1984

5 IQ

115

40 40

4.1.5 equilibria

1981

studies

investigations

-. ltor 'lask

IQ -

I.5

1985

5-25 I

oxides Pa02 and Pa285 9 Attempts to directly measure the csncentration o f oxide ion in Th02-saturated melts by chemicd analysis yielded less precise values57 and EMF measurements using a LaF3 electrodeP8 were UR~~CC~SS~ 59U I~t . 5 5 0 " ~the s~lubilityproauct of T ~ O Z calculated from t h e available d a t a 1 0 9 L 9 9 5 7 is respectively 6 . 9 x 10-es 14.8 x and BO. 7 x Although these values disagree at most by a %actor of 2, they are presently quite useful for estimating the behavior of Th4+ in the presence of 02- and do not jeopardize reactor safety calculations because ThQ2 is the most soluble of the actinide dioxides that csuHd fQ%m in an MSBW. Future research, however, s h o u l d involve a reexamination of t h i s parameter, although not as a high priority t o p i c . Unless an oxidesensitive electrode is developed for use in molten fluorides, the solubility studies will b e performed by equilibration of the oxide-melt system, and subsequent sampling, grinding etc. in a moisture-free inert atmosphere glove box. An alternative determination can be performed by means of the metathesis reaction: e

in which the filtered samples will be analyzed f o r dissolved nickel. 5.4.5.2

Subtask 4.1.1.2

Protactinium oxides

as Protastiniun can be precipitated from molten fluorides as Pa2Q5 binary or ternary solid s o l u t i o n s of PaOzp depending on the redox potential of the system and the other actinides present. The solubility of Pa205 was determined d i r e c t l y i n molten fluorides saturated with Th0z1 and from aeasursments of the equilibrium2*

) Pa28s(e) ~a~g(d)+ 5 / 2 M ~ o (=~ l/2

+ 5~P(g)

together with measurements of the e~pilibrium~~

A s s w i n g that all the protaceinium in the reactor is pentavalent ~f imposes a minimum limit on the concentration of allowable 02-. the Pa5+ concentration in t h e reactsr6l is 1.972 x I D Q ~ ~ / C I I I the ~, oxide concentration allowed at 550°C is, respectively, less than 8.6 x (ref. 19) and 1.23 x (ref 28) The disagreement in these values is tolerable at 550°C but increases with increasing temperature because the temperature effect on the s o l u b i l i t y of Pa205 is more proe

nounced in the values obtained from ref. 19. Due t o this large temperat u r e effect, it w a s suggested19 that the precipitate may have been sdvatecl with Lip. In a long range plan, this discrepancy of t h e temperature dependence and identity of the precipitate will have to be resolved because Pa285 a l s ~participates in other reactions of relevance to the chemistry of the MSBR, such as I.:?*

5-26 t

T h i s r e a c t i o n is important because i t i n d i c a t e s the e f f e c t of redox p o t e n t i a l on the predm2nant species of p r o t a c t i n i u m i n t h e m e l t . From a safety point of view, these d a t a can be used to e s t i m a t e t h e minimum r a t i o of UF3/UFk that should b e used t o keep t h e p r o t a c t i n i u m tetrav a l e n t , in which case t h e c o r r e s p o n d b g oxide e x h i b i t s a h i g h e r s s l u b i l i t y t h a n Pa205.

Although measurements have been made1' potential by means of t h e e q u i l i b r i u m

t o determine t h e e f f e c t of redox

t h e d a t a showed c o n s i d e r a b l e U n c e r t a h t y . The redox p o t e n t i a l of the c o u p l e ~ a P s / ~ a Fwill k b e d e t e m i n e d w i t h h i g h e r precision by means of electroanalytical and s p e c t r o p h o t o m e t r i c methods o r by a t r a n s p i r a t i o n technique 2 o he e l e c t m a n a l y t i ~ a methoa l WCII deternine t h e redox p o t e n t i a l by v o l t m e t r y in a system where the v a l u e of t h e r a t i o i s changed by means of s p a r g i n g w i t h W-H2 m t x t u n r e s , i . e .

The s p e c t r s p h o t m e t r i c method w i l l use. t h e d i f f e r e n c e i n a b s o r p t i v i t y of b o t h p r o t a c t i n i u m species62 t o determine t h e i r r a t i o and t h e tramsp i r a t i o n t e c h n i q u e w i l l .be a r e p e t i t i s r a of earlier measureanents20 b u t ~ t s ihg n i f i c a n t l y l a r g e r m o u n t s of p r o t a c t i n i u m . Independent e x p e r i ~ S protactinium, mental work w i l l be performed ~ 5 t ha p p r e c i a b l e ~ Z R Q U ~ of 2x1 t h e o r d e r of several grams, i n order to p r o v i d e ~ ~ ~ e ~ p i v iod ec nat li fieation of t h e e q u i l 2 b r f . m s o l i d phases p r e s e n t i n t h e system.

5.4.5.3

Subtask 4.1.1.3

B l u t ~ n i uoxides ~~

The o x i d e chemistry of plutonium w a s studied i n several molten f l u o r i d e ~ ~ e l t s . ~It ~ ~w a~s 'found t h a t the a d d i t i s n of o x i d e t o PuF3-containing m e l t s d i d n o t p r e c i p i t a t e any plutonium oxide under mild reducing ~ o n d i t i o n s ,independent of t h e c o ~ ~ p o ~ i t isf o nt h e melt; i.e., LiF-BePZ c o n t a i n i n g ZrF4 o r ThF4 o r the pure s o l v e n t LIF-BeF2. When PuQ2 was added t o a LiP-BeFz m e l t c o n t a i n e d i n n i c k e l , a l l of the p%utoniunt ended up as PuPj i n s o l u t i o n . Speetrophotometric measurements i n molten E ~ F - B ~ F ~ -did T ~ not F ~ reveal the p r e s e n c e of any p1UtC9ILhUiI oxyfluoric1e2~ a l t h o u g h such a compound has been r e p o r t e d t o exist i n t h e solid s t a t e . However, when the o x i d a t i o n s t a t e of t h e system w a s i n c r e a s e d , e . g . , by t h e a d d i t i o n of N i F 2 , it was found t h a t , in the p r e s e n c e of thorium, t h e a d d i t i o n of o x i d e y i e l d e d a s o l i d s o h t i s n of PuQ2-Th02. fie corr e l a t i o n found between d i s t r i b u t i o n q u o t i e n t s and l a t t i c e parameters of p a r e a c t i n i d e o x i d e s a 6 l e d t o the p r e d i c t i o n of a large d i s t r i b u t i o n c o e f f i c i e n t f o r Pu4+ (.IO4); i , e , , i t i s p o s s i b l e t o o b t a i n Fu02-Th02 s o l i d s o l u t i o n s ~ 6 t hv i r t u a l l y p u r e PuQ2. Because the measured dist r i b u t i o n q u o t i e n t of plutonium corresponds t o ~ u 4 + ,t h e d e t e r m i n a t i o n of a large d i s t r i b u t i o n q u o t i e n t w i l l r e q u i r e a redox p o t e n t i a l eons i d e r a b l y more o x i d i z i n g than that of t h e couple N i 2 e / N i o used i n past experiments; t h i s i n t u r n will. r e q u i r e t h e use of metals more n o b l e than nickel f o r containers

5-27

5.4.5.4

Subtask 4.1.1.4

NeDtunium o x i d e s

The c o r r e l a t i o n developed p r e v i o u s l y 1 w a s used f o r p r e d i c t i n g t h a t t e t r a v a l e n t neptunium would behave s i m i l a r l y t o t e t r a v a l e n t plutonium, a l t h o u g h w i t h a s l i g h t l y lower d i s t r i b u t i o n q u o t i e n t . S i n c e no e x p e r i mental d a t a are a v a i l a b l e , t h e behavior of neptunium in oxide-containing molten f l u o r i d e s w i l l be s t u d i e d under v a r i o u s oxlidizing c o n d i t i o n s . These s t u d i e s w i l l be performed s i m u l t a n e o u s l y w i t h d e t e r m i n a t i o n s of the redox p o t e n t i a l , in molten f l u o r i d e s i n t h e absence of o x i d e i o n , of ~ o u p l e sformed by t h e most s t a b l e s p e c i e s of neptunium i n s o l u t i o n .

5.4.6

Task 4.1.2

T e l l u r i u m chemistry

Tellurium, p r e s e n t i n t h e E B R f u e l s a l t as a f i s s i o n p r o d u c t , i s probably r e s p o n s i b l e f o r t h e Z n t e r g r a n u l a r attack observed 5n H a s t e l l o y N samples exposed i n t h e MSRB experiment.21 T h i s w a s a n unexpected r e s u l t and, u n t i l r e c e n t l y , t h e chemistry of t e l l u r i u m i n f l u o r i d e melts had n o t been i n v e s t i g a t e d . The f u e l s a l t i s r e d u c i n g , due t o t h e U3+ c o n t e n t , and t e l l u r i u m would be expected t o be p r e s e n t as t h e dimer, T e 2 , and i n smaller q u a n t i t i e s as t h e monomer, T e , a n d / o r i n a reduced s t a t e . Two l i t h i u m t e l l u r i d e s are ( L i T e 3 and L i z T e ) and t h e two t e l l u r i d e i o n s a r e i n t e r r e l a t e d through t h e f o l l o w i n g e q u a t i o n : 2Te3

- = Te2'

3- 5/22 Te2'.

I f t h e e q u i l i b r i u m c o n s t a n t f o r t h i s r e a c t i o n has a v a l u e n e a r u n i t y , t h e m e l t could s i m u l t a n e o u s l y c o n t a i n s i g n i f i c a n t amounts of b o t h i o n i c s p e c i e s . The o x i d a t i o n s t a t e i s , of c o u r s e , c o n t r o l l e d by t h e U3*/U4+ r a t i o i n t h e MSBR f u e l s a l t , as shown i n t h e f o l l o w i n g e q u a t i o n

where t h e most reduced s t a t e of t e l l u r i u m i s t h e t e l l u r i d e L i z T e . I f , at U3+/U4+ ratios attainable in an o p e r a t i n g MSBR, t h e e q u i l i b r i u m i s s h i f t e d predominately t o t h e l e f t , assuming LF2Te i s t h e s t a b l e s p e c i e s , t h e t e l l u r i u m would n o t be a v a i l a b l e f o r r e a c t i o n w i t h s t r u c t u r a l m e t a l s such - as N i 0 o r C r 0 s i n c e i t cannot be f u r t h e r reduced. I f , however, Te3 i s p r e s e n t , t h i s argument m y n o t be v a l i d due t o t h e d i s p r o p o r 0 Conversely, i f t h e e q u i l i b r i u m i s tionation reaction yielding Te2 s h i f t e d predominately t o t h e r i g h t , t h e t e l l u r i u m would be p r e s e n t as an e l e m e n t a l gas which i s expected to have a v e r y low s o l u b i l i t y i n f l u o r i d e m e l t s and t h u s should d i s t r i b u t e t o t h e cover gas where i t could p o s s i b l y be removed in a s i d e - s t r e a m p u r i f i c a t i o n s t e p . Thus, i t can be s e e n that i n f o r m a t i o n on t h e s e two e q u i l i b r i a must be developed t o understand t h e c h e m i s t r y of t e l l u r i u m r e l a t e d t o tellurium-indueed c r a c k i n g of H a s t e l l o y N. The f o l l o w i n g s u b t a s k s have been d e f i n e d t o e l u c i d a t e these r e a c t i o n s . a

5-28

5.4.6.1

Subtask 4 . 1 . 2 . 1 molten s a l t s

S o l u b i l i t y of t e l l u r i u m and tellurides i n

Before S)PSte&Eitic inVeSidgatiO€I of the e q u i l i b r i a l i s t e d above Can b e i n i t i a t e d , it i s n e c e s s a r y t o deternine the s ~ l u b i l i t y -sf t e l l u r i u m as and of t h e solid t e l l u r i d e s LiTe3 and ki2Te i n f l u o r i d e m e l t s . This will b e done f i r s t i n Ei2l8eFqp f o r experimental s i m p l i c i t y - , and t h e n i n f u e l salt c o n t a i n i n g thorium fluoride at temperatures ranging from 500 t o 88Q'C t o cover the expected m i n i m u m and mxiwum f u e l s a l t temperatures of 1000 and l300'P t o be encountered i n an o p e r a t i n g MSBR.' It has been calculated6' t h a t t h e s o l u b i l i t y of t e l l u r i u m i n molten f l u o r i d e s a t 6 W 0 C s h o u l d b e approximate%y lo-" mole f r a c t i o n T e 2 and about mole f r a c t i ~ nTe. Direct measurements22 gave a v a l u e of less than 7.7 x 16-5 mole f r a c t i o n a t 6 5 5 ' ~ i n ~ i 2 1 4 e ~ 4 . his apparent POW SCllUbility will n@CeSSitate a K e h l t i V d g r S o p h i s t i c a t e d @Xperimental d e s i g n t o o b t a i n an a c c u r a t e measurement of the s o l u b i l i t y of telkuriun. The use of r a d i o c h e m i c a l - t r a c e r t e l l u r i m m y b e n e c e s s a r y to obtain a n a l y t i c a l data, which could n e c e s s i t a t e g l o v e box i s o l a t i o n of t h e a p p a r a t u s . A Henry's l a w constant can t h e n b e calculated f o r t h e s o l u b i l i t y of telluri~mgas in Ei2BeF4 and in f u e l salt. b e more soluble t h a n e l e m e ~ ~ t a l t e l l u r i u m and a d i f f e r e n t e x p e r i m e n t a l procedure will b e r e q u i r e d for the d e t e r m i n a t i o n of t h e i ~. ~ O ~ u b i ~p ri ot d)u~c t s . P r e l i m i n a r y r e s u ~ t s ~ ~ Suggest an a p p r e c i a b l e s o l ~ b i l i t yO f L i T e 3 in molten f l ~ ~ r i d e L s i;2 T ~ t is known to be s o l u b l e t~ at least Q,05 mole f r a c t i o n i n LiC1-LIP m i x t u r e s a t 525'C. P r i o r t o s o l u b i l i t y measurements, however, i t will The Li3Te can b e purchased b u t most be n e c e s s a r y t o s y n t h e s i z e LiTe.3. l i k e l y w i l l have t o be r e p u r i f i e d . Attention w i l l be drawn t o t h e d e t e c t i o n of s i g n i f i c a n t mounts Of %e2 in the gas phase as a consequence of the d i s s o l u t i o n of L i T e 3 . This would i n d i c a t e t h e s t a b i l i t y A stirred p o t o r r o c k i n g v e s s e l with a g r a p h i t e i n solution of t h e Te3-. o r boron nitride crucible 8% liner could b e u t i l i z e d i n t h e t e m p e r a t u r e Samples for a n a l y s i s range 500-800"C f a r these s o l u b i l i t y measurements. would be withdrawn through f i l t e r s t i c k ~and ~ ~ t h e t e l l u r i u m content of t h e cooled samples c s u l d be d e t e ~ a n i ~ e~dO W Bto ~ the 1-10 ppm range by i s o t o p i c d i l u t i o n and mass spectrometry or9 a t h i g h e r l e v e l s , by wet chemical a n a l y s i s . If Te3- d i s p r ~ p ~ ~ t i o n ssti g e n~ i f i c a n t l y , t h e b e h a v i o r of t h i s ion would ' t ~ es t u a i e d s p e c t ~ o p h o t s m e t ~ i e a lwl yi t h a c e l l and f u r n a c e i n t h e l i g h t p a t h of t h e i n s t r u m e n t . Quartz c e l l s W@Ke Used ill plreViOUs StudieSZ29 6 5 and, f o r longeP-te?Xl s t a b i l i t y , cells cut from s i n g l e c r y s t a l s of lanthanum fluoride o r diamond-window g r a p h i t e c e l l s map b e used. It may be p o s s i b l e to measure t h e eoncentrafUnctisIk Sf t-SQerELtLS%e, t i O n of these i O n S d i K @ C t l y at t a p e r a t u K @ %S m e l t composition, T e 2 p r e s s u r e s e t c . S i n c e no l i g h t a b s o r p t i o n which would ~ o r r e ~ p o nto d t h e a b s o r p t i o n by Te2- was detected,22 the determinat i o n of the s o l u b i l i t y of L i 2 T e will i n d i c a t e whether T e'exhibits any a b s o r p t i o n i n t h e comon spectral range. I f the s p e c t r a overlap to some e x t e n t , it m y b e p o s s i b l e t o ~ e s o l v ethem through computer treatment of t h e data. Measurements would b e made i n b ~ t hLizBeF4 and thoriumc o n t a i n i n g fuel s a l t .

The t e l l u p i d e s E i T e 3 and E f 2 T e

.... & ..

5-29

Even though Te3- is s t a b l e Ln m e l t s c o n t a i n e d i n quartz, and appears u n s t a b l e i n the presence of stron metallic r e d u c t a n t s such as chromium and b e r y l l i ~ , ’ i~t i s n e c e s s a r y t o know whether more noble metals and a l l o y s @E, HastelPoy, e t c . ) can decompose t h e Te3-. This can be learned from s p e c t r o p h o t o m e t r i c m e a w r m e n t s sirnilar t o t h o s e d e s c r i b e d i n t h e previous t a s k . 5.4.6.3

Subtask 4.1.2.3 Oxidation-reductton chmistrgr of t e l l u r i m i n f a e l s a l t esratainhg uranihm

With the i n f o m a t i o n developed i r n the two p r e v i o u s subtaska it w i l l be p o s s i b l e t o d e s i g n experiments t o measure the effect of the ~ 3 + / ~ 4 f r a t i o i n t h e f u e l salt on the s p e c i e s of t e l l u r i u m p r e s e n t and on their d i s t r 2 b u t i o n between gas, liquid and solid phases. The solEds could be i n s o l u b l e tellurides of l i - t h i m o r otheH m e l t c o n s t i t u e n t s such as uranium te11uride,6’¶6* UT^. me free energies 0% formation of the tpitriouls t e l l u r i d e s are n o t ICII~WTB~ with the e x c e p t i o n 6 9 sf L P ~ T ~and , it is not p o s s i b l e t o p r e d i c t which t e l l u r i d e Would be l e a s t s o h b l e . P r m the resnlts of t k s e experiments i t may be p o s s i b l e t o propose methods f o r d e a l i n g w i t h t e l l u r i u m i n t h e MSBW system.

The EiXperblentS Would be C a r r i e d O u t i n a stirred Vessel roCkiKkg reactor a t temperatures of 5Q0-88OoC. P r o v i s i o n would be made for a d j u s t i n g t h e U3+/UW r a t i o d u r i n g an e x p e r i m e n t a l run. It would be d e s i r a b l e t o use s p e c t r o p h o t m e t r i c methods f o r o n - l i n e a n a l y s i s ; however, i f uranium absorbance n e g a t e s that method i t may be possible t o use p o t e n t i m e t r f c . methods. If t h e tellurium s o l u b i l i t y i s h i g h enough, smples could be d t h d r a m through a f i l t e r stick and s u b s e q u e n t l y analyzed.

5.4.4.4

Subtask 4.1.2.4

Preparatfon of metallumgieal samples

A test f a c i l i t y t o expose m e t a l l u r g i c a l samples t o c o n t r o l l e d of tellurium a t e l e v a t e d temperatures dll be an i n t e g r a l p a r t of t h e program descrzbed i n Seetion 2 t o develop modified HastePloy M a l l o y s which are r e s i s t a n t t o tellurium bte-rrgrarnular attack. F a c i l i t i e s ~511 be designed t o s i m u l a t e exposure of t h e MSBR containment vessel both eo telluriurra gas in the vapor s p a c e above the f u e l salt and t o c o n t a c t with s a l t c o n t a i n i n g t e l l u ~ and/or f ~ tellurides. ~t i s b p o r t a n t t o i n v e s t i g a t e the attack on samples in f l u o r i d e m e l t s s i n c e the molten s a l t could s t r i p p r o t e c t i v e f i h s of o x i d e o r f l u o r i d e s from t h e s p e c h e n s and accelerate S a i m boundary corrosion. For t h e vapor-phase exposure, t h e t e n s i l e test s p e c h e n s and a c a l c u l a t e d amount of t e l l u r i u m m e t a l w i l l be p l a c e d %nevacuated q u a r t z tubes such t h a t t h e sample and the t e l l u r i u m can b e h e l d a t d i f f e r e n t Thus, t h e specimen

5-30 I

can b e maintained a t any d e s i g n a t e d temperature and t h e d e p o s i t i o n rate of t h e t e l l u r i u m can b e h d e p e n d e n t l y e s t a b l i s h e d . In the i n i t i a l tests, a lO86-hr d e p o s i t i o n period w i l l be m p l o y e d . I

A d i f f e r e n t e x p e r i m e n t a l approach w i l l be r e q u i r e d t o s i m u l a t e exposure to t e l l u r i u m - c o n t a i n i n g f u e l s a l t . Agafn, a r e a c t i o n vessel w i t h a g r a p h i t e o r boron n i t r i d e H n e r wtll be employed. The samples would be placed i n the f l u o r i d e m e l t in the c r u c i b l e and m a i n t a i n e d at tE3lpeTb-atU~e. The tedlUrilX€l could be tralaSfe%red at a c Q R t r o l l @ dr a t e t o t h e m e l t by evaporatton S% tellurfiam m e t a l a t a lower temperature or could be added a t i n t e r v a l s as s o l i d Li2'Fe andlor LiTe3.

5.4.9

Task 4.6.3

Phase behavior of PuFg i n f u e l s a l t

The s o l u b i l i t y of PuF3 i n LiP-BeF2-ThFq (72-16-12 mole 2) has been measured at O E J L ~ and ~ a t the ~ ~ a a ~~ bt am t e Research c e n t r e , 1ndia.25 The v a l u e s measured i n I n d i a are about 20% lower than those a t ORNL. The OWL d a t a resulted from t h e e independent methods ~f a n a l y s e s : y - count5ng o f the 241h p r e s e n t , a-pulse-height c o u n t i n g , and neutron activation. D e t e m h a t i o n s of plutonium i n I n d i a were made by means of p o t e n t i s m e t r y and a-pulse-height counting. A reexamination of t h e exp e r b e n t a l techniques employed a t O m and, t o a lesser e x t e n t of t h o s e The d a t a a t BmC, d i d n o t reveal the s o u r c e of t h e discrepancy.71 revealed good i n t e r n a l c o n s i s t e n ~ yfor eaeh s e t , thus s u g g e s t i n g that the d i f f e r e n c e noted may be due to d i f f e r e n c e s between t h e plutonium standards used by each a n a l y t i c a l group. S i n c e BBaabba A t o m i c Research Centre has measured t h e s o l u b i l i t y of PuF3 i n a wide c m p o s f t i o n range of molten fluorides, i t s e e m s seasonable to ~ee~abtllath e e analytical methods used f o r p l u t o n h m a t ON% followed, if n e c e s s a r y , by m e a s u r a e n t s of the s o l u b i l i t y of Pup3 i n molten f l u o r i d e s of composition near that proposed for MSBR f u e l s .

5.4.8

Task 4.1.4

Fuel-coolant i n t e r a c t i o n s t u d i e s

The c o n c e p t u a l d e s i g n of a lOOQ-M(e) MSBR power s t a t i o n ' " c a l l s for four shell-and-tube type p r h a r y heat g~changers, each having 5896 tubes of 3/8-ina-dimeter and 22.2 f t in l e n g t h . It i s assumed t h a t some t u b e f a i l u r e s w i l l o c c u ~d u r i n g the l i f e of t h e power s t a t i o n ; therefore, t h e heat exchanger d e s f g n incorporates p r o v i s i o n s for tubebundle replacement o s tube pluggln by remote o p e r a t i o n . Tube f a i l u r e s w i l l , of c o u r s e , lead to mixing of f u e l s a l t and c o o l a n t . It i s n e c e s s a r y that s u f f i c i e n t h o w l e d g e be developed t o assure that e v e n t s r e s u l t i n g from such mixing do n o t lead t o consequences which could endanger t h e s a f e t y o r v i a b i l i t y of t h e r e a c t o r system.

5-31

Some e x p e r i m e n t a l work has been done p r e v i o u s l y t o i n v e s t i g a t e f u e l and c o o l a n t mixing. In some cases, however, t h e r e s u l t s were prel i m i n a r y i n n a t u r e and, to some e x t e n t i n c o n c l u s i v e , a t l e a s t as f a r as d e f i n i n g p r a c t i c a l o p e r a t i n g parameters d t h r e g a r d t o r e a c t o r s a f e t y . It w a s found" t h a t two immiscible phases r e s u l t e d when NaBF4 o r KBF4 ( t h e s e experiments d i d not use t h e e u t e c t i c c o o l a n t m i x t u r e of NaBF4 and NaF) and v a r i o u s f l u o r i d e m i x t u r e s were mixed a t 480°C. No chemical a n a l y s e s of t h e major components of t h e phases were o b t a i n e d and no BF3 p r e s s u r e measurements were wade. The p r e s e n c e of UFQ i n t h e NaBF4-rich phase could not b e d e t e c t e d s p e c t r o p h o t o m e t r i c a 8 l y . bn a n o t h e r series of tests a t 600'6, m i x t u r e s of NaBP4 and Li2BeF4 were h e a t e d i n n i c k e l c a p s u l e s , quenched, and t h e two phases analyzed. +The re u l t i n g phases appeared t o b e r e c i p r o c a l mixtures of t h e i o n s L i Sa BF4 and BePk2- and a p p r e c i a b l e q u a n t i t i e s of a l l i o n s w e r e found i n b o t h phases. Changes i n m i s c i b i l i t y can occur r a p i d l y w i t h changes i n t e m p e r a t u r e , and quenching t h e m e l t p r i o r t o sarnpbing i s n o t a n i d e a l procedure s i n c e s u b s t a n t i a l r e d i s t r i b u t i o n of components could occur d u r i n g c~01i11g

One series of experiments w a s c a r r i e d o u t t o i n v e s t i g a t e t h e BP3 p r e s s u r e over one m i x t u r e s f LiF-BeP2-ThF4 (72-16-12 mole W > and NaBF4-NaP (92-8 mole X > c o o l a n t . 7 2 The m i x t u r e w a s n o t s t i r r e d and w a s s l o w l y heated i n an a u t o c l a v e . P r e s s u r e r e a d i n g s w e r e recorded t o 647'C where an o v e r p r e s s u r e of 9% p s i a w a s o b t a i n e d . The magnitude of t h e r e p o r t e d p r e s s u r e w a s l 3 t i m e s h i g h e r t h a n t h e BP3 p r e s s u r e over NaBF4-MaF (92-8 mole X > a t a given temperature. E q u i l i b r a t i o n was achieved o n l y s l o w l y , and t h e p r e s s u r e continued t o i n c r e a s e a f t e r t h e measurements were recorded and BF3 w a s t h e n vented t o t h e hood. The BP3 can b e c o n s i d e r e d t o b e g e n e r a t e d by d i s s o c i a t i o n of t h e NaBP4 and d i s s o l u t i o n of t h e NaP in t h e f u e l s a l t , t h u s lowering t h e NaF a c t i v i t y

Questions c ~ ~ ~ e r n tihne ga t t a i n m e n t of e q u i l i b r i u m i n t h i s experiment s u g g e s t t h a t the r e s u l t s m y n o t r e p r e s e n t t h e maximum p r e s s u r e . Also, t h e i n v e s t i g a t i o n covered o n l y one r a t i o of f u e l and c o o l a n t . Subsequently, a c a r e f u l i n v e s t i g a t i o n of t h e s o l u b i l i t y of BP3 i n fuel. salt w a s completed36 and t h e e q u i l i b r i u m BF3 p r e s s u r e s were measured f o r several molten s a l t C O ~ ~ Q S ~ ~ ~ over O I I Sa wide temperature range. In some experiments NaP was added, g i v i n g a composition of LiP-BeP2-ThF4NaP (66-15-11-8 mole %> to s i m u l a t e t h e in-leakage of NaBF4 coolant to f u e l s a l t . The e q u i l i b r a t e d molten salt w a s not examined f o r twophase f o r m a t i o n b u t d i s c o n t i n u i t i e s w e r e n o t encountered i n t h e BF3 p r e s s u r e d a t a , s u g g e s t i n g t h a t no phase disengagement o c c u r r e d . Considera t i o n of t h e r e s u l t of small l e a k s and massive l e a k s of c o o l a n t i n t o f u e l i n d i c a t e d t h a t excessive BF3 p r e s s u r e s would not b e encountered.

5-32 I n t h e o p e r a t i o n of a Parge pump l o o p w i t h NaBFb-NaF ( 9 2 - 8 mole Z) c o o l a n t , 3 a uranium-and thorium-containing p r e c i p i t a t e was o b t a i n e d which r e s u l t e d from t h e mixing o f r e s i d u a % f u e l s a l t i n t h e l o o p with t h e f l u s h charge sf c o o l a n t . T h i s was reportedi17 t o b e SNaF-6(ThSU)P4. n e s e r e s u l t s are c o n s i s t e n t w i t h the p r e v i o u s finding26 t h a t UP^ w a s i n s o l u b l e in NaBF4. These experiments a r e s u b j e c t t o criticism i n t h a t t h e y a r e i n some i n s t a n c e s ( a ) p r e l i m i n a r y , ( b ) do not c o v e r t h e t e m p e r a t u r e range of 8 5 0 - 1 3 0 0 " ~ expected i n the primary h e a t exchangers,4 ( c ) cover o n l y one o r a l i m i t e d range of f u e l - c o o l a n t r a t i o s and, ( d ) in one c a s e , represemt a r e l a t i v e l y u n c o n t r o l l e d mixing experiment. R e g a r d l e s s , it: i s p o s s i b l e t o draw some g e n e r a l i z e d conclusions concerning t h e r e s u l t s of mixing,

If f u e l leaks i n t o t h e c o o l a n t , t h e uranium and thorium w i l l p r e c i p i t a t e . Probably most o r a l l of t h e t r i v a l e n t o r h i g h e r - v a l e n t c a t i o n s , such as p r o t a c t i n i u m , f i s s i o n p r o d u c t s , e t c . , would a l s o p r e c i p i t a t e . Two immiscible phases may b e formed when l a r g e volumes of f u e l leak i n t o t h e c o o l a n t and many of t h e c o n s t i t u e n t s may d i s t r i b u t e between t h e s e phases. In addition, radioactfve contamination of t h e c o o l a n t system would r e s u l t 0

If c o o l a n t l e a k s i n t o t h e f u e l , it i s l e s s c l e a r what e v e n t s w i l l o c c u r . The NaBF4 w i l l partially d i s s o ~ i a t eand BF3 gas will be evolved. I t is n o t known if this would evolve smoothly or i n s u r g e s as t h e ~ W Qimiscibislle l i q u i d s r e a c t e d . E v e n t u a l l y , a f t e r some unknown volume of c o o l a n t mixes w i t h f u e l , t w o s t a b l e immiscible phases may b e formed and a l l t h e ions may d i s t r i b u t e between t h e s e two phases. It is n o t p o s s i b l e t o p r e d i c t what t h e uranium o r thorium c o n c e n t r a t i o n W Q U ~b e~ i n each phase. I n a d d i t i o n , af c o u r s e , boron i s a r ~ u c l e a rp o i s o n and must be removed ( a s BF3 g a s ) f o r t h e f u e l t~ b e o p e r a b l e ; v e r y s m a l l concentrat i o n s would b e removed by n e u t r o n a b s o r p t i o n .

In o r d e r t o resolve t h e s e important s a f e t y - r e l a t e d q u e s t i o n s , t h e f o l l o w i n g s u b t a s k s have been d e f i n e d t o i n v e s t i g a t e t h e phase e q u i l i b r i a , t h e d i s t r i b u t i o n of major and minor campsnents between t h e two p h a s e s and t o s i m u l a t e t h e dynamfc n s n - e q u i l i b r i u m c o n d i t i o n s t o b e e n c ~ u n t e r ~ d i n an a c t u a l l e a k . Leaks i n either d i r e c t i o n through t h e h e a t exchanger w i l l be c o n s i d e r e d ; f u e l i n t o c o o l a n t as well as cookant i n t o f u e l . The experiments s h o u l d also i n d i c a t e t h e e v e n t s t o b e encountered i n t r a n s i e n t s i t u a t i o n s , f o r example csoEing t h e salt after r e a c t o r s h u t down Following d e t e c t i o n s f a l e a k . S i n c e phase i m i s e i b i l i t y can b e h i g h l y temperature dependent, two-phase formation could b e more pronounced a t lower t e m p e r a t u r e s d u r i n g SOCII down. E6 t h e r e i s s u b s t a n t i a l d i s t r i b u t i o n of t h e components beeween t h e phases, t h e f r e e z i n g p o i n t of t h e new phases c o u l d b e s u b s t a n t i a l l y d i f f e r e n t from f u e l o r c o o l a n t . If t h e f r e e z i n g pinat i s h i g h e r , t h e n material could f r e e z e FR t h e h e a t exchanger i n t h e v i c i n i t y s f a leak.

5-33 I

5.4.8.1

Subtask 4.1.4.1

Phase e q u i l i b r i a

me pre1Yfiainary e ~ p e r h e n t ssuggested ~~ that two irmnisci~lephases couisl be formed when fuel and c o o l a n t were m a e d , b u t t h e r a t i o of f u e l t o c ~ o l a n tover which t h i s b e h a v i o r o c c u r s and t h e composition of t h e phases w e r e n o t w e l l d e f i n e d . The ffrst series of experiments w i l l i n v e s t i g a t e t h e mfxing a t wide ranges of f u e l / c o o l a n t r a t i o , t h u s s i m u l a t i n g l e a k s in e i t h e r d i r e c t i o n through t h e primary h e a t exchanger, and over a tempera t u r e range from t h e m a x h u m anticipated temperature t o t h e freezing p o i n t of t h e phases. The experiments will be designed S O t h a t t h e V O ~ U I R ~ of t h e r e s u l t i n g phases can be measured and the phases can be sampled at temperature. For s h o r t tern a p e r k e n t s , q u a r t z containment may be a d e q u t e arid Would s h p l i f y ObS@%%vatiOn Qf the two phases. FQf- longer tern experiments a t the higher t e m p e r a t u r e s , t h e = p e ~ i m e n t s could be r e p e a t e d i n n i c k e l o r H a s t e l l s y N r e a c t o r s t o avoid S i F 4 and oxide cont a m i n a t i o n of t h e m e l t . The c o n d u c t i v i t y of t h e two phases may be s u f f i c i e n t l y d i s s i m i l a r t h a t an a d j u s t a b l e c o n d u c t i v t t y probe e s u l d be Used t o locate the i n t e r f a c e . A c m p l e t e a n a l y s i s be p e r f ~ r m e d f o r all m e l t c o n s t i t u e n t s , b o t h m a j o r and minor. The p r e s s u r e would be maintained a r b i t r a r i l y a t 1 atmosphere and the q u a n t i t y of BP3 evolved would be measured. It may b e n e c e s s a r y to s t i r t h e r e a c t i o n vessel t o ensure r a p i d a t t a i n m e n t of e q u i l i b r i u m . Since, i n an MSBR, t h e g a s space over t h e f u e l ~ L l l lb e s w e p t w i t h helium, i t may be d e s i r a b l e t o subsequently i n t r o d u c e t h a t f e a t u r e i n t h e e x p e r i m e n t a l d e s i g n t o evaluate the r e s i d u a l BF3 c m p o s i t i o n of the m e l t . With t h e i n f o m a t i o n developed i n t h e s e experiments, i t w i l l b e p o s s i b l e to e v a l u a t e t h e problems of phase i m m i s c i b i l i t y , u r a n h m and t h o r i m d i s t r i b u t i o n and p r e c i p i t a t i o n , and f r e e z i n g p o i n t d e p r e s s i o n .

A d d i t i o n a l experiments may t h e n be needed t o d e f i n e t h e d i s t r i b u t i o n of plutonium and p o s s i b l y other a c t i n i d e s s i n c e s m e MSBR concepts i n c l u d e u s i n g plutonium as the i n i t i a l f u e l , and m o l t e n - s a l t c o n v e r t e r r e a c t o r s could o p e r a t e w i t h plutonium f u e l makeup. It i s d e s i r a b l e t o i n v e s t i g a t e t h e d f s t r t b u t i o n of f i s s i o n product elements in the two-phase system. If radisaetAve tracers are used, these experiments may require some s h i e l d i n g .

5.4.8.2

Subtask 4.1.4.2

Dynamic investigations

The phase equilFBria experiments d e s c r i b e d i n the p r e c e e d i n g s e c t i o n p l u s t h e p r e v i o u s l y completed BP3 p r e s s u r e data36 w i l l be adequate t o e v a l u a t e t h e e f f e c t of s m a l l l e a k s . Large Ieaks, or the sudden mtxing of Parge volmes of f u e l and c o o l a n t , p r e s e n t a more complex s i t u a t i o n . They i n v o l v e a non-equilibrium s i t u a t i o n and d l y r t ~ ~ ~experiments ~fc must be c a r r i e d o u t t o i n v e s t i g a t e r e a c t i o n rates i n a d d i t i o n t o equilibrium conditions.

5-34

c.;.... .

The rate of e v o l u t i o n of BF3 gas f o l l o w i n g a sudden mixing i s important i n determining the maximum t r a n s i e n t p r e s s u r e i n a damaged h e a t exchanger and i n e v a l u a t i n g t h e p o t e n t i a l f o r p h y s i c a l f a i l u r e of t h e h e a t exchanger s h e l l . To measure t h e rate of r e a c t i o n of c o o l a n t and f u e l , a s u i t a b l e experimental s t a n d a l l o w i n g f o r p r e s s u r e t r a n s i e n t s would be r e q u i r e d . Pressure t r a n s d u c e r s c a p a b l e of r e c o r d i n g p r e s s u r e t r a n s i e n t s would be u t i l i z e d and volumes of f u e l and c o o l a n t would be mixed under w e l l d e f i n e d c o n d i t i o n s .

In t h e case of a l e a k of c o o l a n t into f u e l -s a l t , t h e environment i n t h e area n e a r t h e Peak w i l l b e high i n BF4 c o n c e n t r a t i o n , and i n s o l u b l e f l u o r i d e s such as t h e 7NaF-6 (Th,U)F4 p r e v i o u s l y observed27 may b e formed. i n t o t h e bulk ~ h e s ewould b e d i s p e r s e d by t h e fuel s a l t ~ I S W ana of t h e f u e l s a l t i n t h e r e a c t o r . I f t h e y do n o t r e a d i l y r e d i s s o l v e , d e p o s i t s of s o l i d s could develop; t h u s , t h e r a t e of r e d i s s o l u t i o n of t h e uranium-thorium p r e c i p i t a t e i n f u e l s a l t needs t o be examined. T y p i c a l s o l i d p r e c i p i t a t e s would b e prepared and t h e i r r a t e s f d i s s o l u t i o n s t u d i e d . These experiments c o u l d b e c a r r i e d o u t i n c o n v e n t i o n a l s t i r r e d n i c k e l r e a c t o r s and t h e c o n t e n t s sampled. The p o s s i b i l i t y o f f r e e z i n g a phase having a h i g h e r melting p o i n t 5n t h e v i c i n i t y s f a l e a k due t o non-equilibrium c o n c e n t r a t i o n s n e a r t h e leak would be i n v e s t i g a t e d . I n a d d i t i o n t o mathematical s i m u l a t i o n of t h e h e a t t r a m s f e r i n suck a s i t u a t i o n , a t e s t a p p a r a t u s could be b u i l t to demonstrate t h e p o t e n t i a l for f r e e z i n g w i t h v a r i o u s c o n t r o l l e d l e a k rates

5.4.9

Task 4.1.5

P h y s i c a l p r o p e r t y d e t e r m i n a t i o n s on f u e l s a l t

The l a s t c r i t i c a l l y - c o m p i l e d set of p h y s i c a l p r o p e r t i e s of p o s s i b l e s i n c e tlzen, fuel s a l t compositions w a s reported28 i n ~ u g ~ 1968. s t d e n s i t y and v i s c o s i t y of several f l u o r i d e m e l t s have been measured. 29 From t h e s e measurements, t h e d e n s i t y and v i s c o s i t y of f u e l s a l t are known, r e s p e c t i v e l y , t o +3% and +lO%. The h e a t - c a p a c i t y of f u e l s a l t LiF-BeF2-ThFq (72-15-12 mol; %> has been d e r i v e d from drop calorime t r ~ OH ; ~t h~e b a s i s of this d e t e r m i n a t i o n and a s i m p l e model f o r p r e d i c t i n g h e a t c a p a c i t y of molten f l u o r i d e s , one can r e l i a b l y p r e d i c t t h e h e a t - c a p a c i t y of t h e f u e l s a l t . Thermal c o n d u c t i v i t y i s the key p r o p e r t y f o r p r e d i c t i n g h e a t - t r a n s f e r c o e f f i c i e n t s of molten f l u o ~ - i e l e s . Measurements t h a t are probably a c c u r a t e t o +10 t o 15%have been o b t a i n e d f o r &iF-BeF2-ThF4-UF4 (69.5-28-12-0.5 m o l e X) 74 It will b e h e l p f u l f o r f u t u r e d e s i g n cons i d e r a t i o n s t o develop an a p p a r a t u s t o measure thermal c o n d u c t i v i t i e s of f l u o r i d e s w i t h g r e a t e r accuracy and t o d e t e r ~ t ~ i nteh e c o n d u c t i v i t y of the p r e s e n t l y proposed f u e l s a l t composition i n such an a p p a r a t u s . The s u r f a c e p h y s i c a l p r o p e r t i e s ( s u r f a c e t e n s i o n and i n t e r f a c i a l t e n s i o n between sa16 and g r a p h i t e ) a r e o n l y known q u a l i t a t i v e l y , Such propert i e s are i n p o r t a n t i n a s s e s s i n g w e t t i n g behavior and i n d e t e r m i n i n g t h e degree of p e n e t r a t i o n of s a l t i n t o g r a p h i t e .

I ,

L..

5-35 T k c v a ~ o rgxessureP as y e t unmeasured, has been e x t r a p o l a t e d from measurements of LLP-BeF2 and LiP-UFk m i x t u r e s . A t t h e h i g h e s t normal o p e r a t i n g temperature, 7 Q 4 " C , t h e e s t i m a t e d vapor p r e s s u r e i s approxi m a t e l y BO-' t o r r . The vapor composition h a s n o t been measured b u t would b e c o n s i d e r a b l y e n r i c h e d i n BeF2 and, peThaps, i n ThP4. Vapor p r e s s u r e and vapor composition are n o t h i g h - p r i o r i t y measurements. However, c a l c u l a t i o n s of how much salt and of what composition is t r a n s p o r t e d by gas s p a r g i n g t o c o o l p o r t i o n s of t h e off-gas system i n t h e primary system ~511 requ2re s a n e t h i n g m o r e than q u a l i t a t i v e estimates. A t r a n s p i r a t i o n experiment would p r o v i d e firm v a l u e s of vapor composition and improved values of t h e vapor p r e s s u r e . Manometric measurements combined w i t h mass-spectrographic d e t e r m i n a t i o n would p r u v i d e more p r e c i s e i n f o r m a t i o n on both.

5.4.9.1

Subtask 4.1.5.1

Thermal c o n d u c t i v i t y

An i n v e s t i g a t i o n would be made t o determine i f t h e v a r i a b l e - g a p appar a t u s p r e v i o u s l y usea75 i s s u i t a b l e f o r f u r t h e r measurements. 1% n o t C o n s i d e r a t i o n would be given as t o whether a modified v a r i a b l e - g a p , hot-wire, o r some o t h e r t e c h n i q u e might be more s u i t a b l e . There i s also some v i r t u e i n t e s t i n g a l l m o l t e n - s a l t thermal c o n d u c t i v i t y d a t a a g a i n s t models by which thermal c o n d u c t i v i t y can be a d e q u a t e l y p r e d i c t e d .

5.4.9.2

Subtask 4 . 1 . 5 . 2

Surface p r o p e r t i e s

A v i s u a l s e s s i l e - d r o p a p p a r a t u s would be assembled t o examine c o n t a c t angles of f u e l s a l t on g r a p h i t e s ; t h e sirme g e n e r a l a p p a r a t u s would be used w i t h l i q u i d m e t a l s and s a l t s of i n t e r e s t to c h m i c a f p r o c e s s i n g . Apparatus would be assembled and speTated to measure surface t e n s i o n of s a l t s (and perhaps m e t a l s ) by t h e maximum bubble p r e s s u r e t e c h n i q u e . The s a l t - g r a p h i t e I n t e r f a c i a l s t u d i e s i n i t i a t e d p r e v i o u s l y would be completed.

The p r e s s u r e and composition of vapor of MSBR f u e l s a l t would be measured by a combination of t r a n s p i r a t i o n , vapor-pressure and masss p e c t r o g r a p h i c d e t e r m i n a t i o n s over t h e temperature range 580" t o 1400°C.

5.4.10

Task 4 . I. 6

U3*/U4*

equilibria studies

Experience with t h e f u e l s a l t redox chemistry has shown t h a t t h e upper and lower l i m i t s of t h e U3+/U4+ r a t i o t h a t are p e r m i s s i b l e i n an MSBR are governed by several f a c t o r s . The r a t i o must be high enough t o p r e v e n t c o r r o s i o n of t h e c o n t a i n e r through t h e r e a c t i o n : ...,, ... .A,d

,:.&

,.... .... :::*

5-36 and t o prevent t h e p r e c i p i t a t i o n of Ba205 through the r e a c t i o n :

I t has been estimatedT6 t h a t r a t i o s g r e a t e r than 0.05 should b e adequate in c o n t r o l l i n g both of t h e s e p r o c e s s e s .

On the other hand, t h e ratio must b e low enough t o p r e v e n t r e a c t i o n o f w i t h g r a p h i t e through t h e r e a c t i o n

u'*

It has been shown3Q t h a t , a t 55Q"C, r a t i o s less -than 0.1 f o r t y p i c a l f u e l s a l t c o n c e n t r a t i o n s w i l l b e s t a b l e i n s o l ~ t i o nw~i t h f r e e f l u o r i d e i o n c o n c e n t r a t i o n s similar t o E i 2 B e F h Evidence has a l s o been which s u g g e s t s t h a t oxide i m p u r i t i e s may s h i f t the abuve c a r b i d e e q u i l i b r i u m tU t h e r i g h t by t h e f€JTXlatiQn o f s t a b l e Uranim oxycarbide p h a e s . ~f such oxyearbide phases do indeed ~ o r m ,t h e u~*/v'+ ratio m y have t o b e h e l d a t v a l u e s less t h a n t h a n 0.1. The e f f e c t of oxygen-related i m p u r i t i e s on t h e UP~-UPL; soPutisn e q u i l i b rim w i l l b e examined to determine t o what e x t e n t low c o n c e n t r a t i o n s of oxide s h i f t t h e maximum TJ3+/V4+ r a t i o which i s o t h e r w i s e determined by 4UF,(d) + 26 ( g r a p h i t e ) = 3UP4(d> f U @ , ( S > . The p o s s i b l e fOrZEKtiQll o f ~ ~ a n i uoxycarbide m phases w h e n U3+ reacts w i t h g r a p h i t e i n t h e p r e s e n c e of oxide. fan w i l l b e examined from 450 t o 708'C. I d e n t i f i c a t i o n of t h e s e phases will b e made and r e l a t e d t o t h e o x i d e ion c o n ~ e ~ t r a t i o fofh t h e m e l t and/or oxygen p a r t i a l p r e s s u r e over t h e system,

Tke c h i e f e x p e r i m e n t a l t e c h n i q u e to b e used i n t h i s s t u d y i s t h e measurement o f UF3 and UF4 c o n c e n t r a t i o n s of f u e l s a l t s i n the t e m p e r a t u r e range of i n t e r e s t u s i n g a diamond-windowed cell. S p e c t r a i n the n e a r - i n f r a r e d and v i s i b l e r e g i o n s w i l l b e g e n e r a t e d by means of a Cary-14 H spectrometer. I n a d d i t i o n , long term e q u i l i b r a t i o n s t u d i e s w i l l be conducted i n s e a l e d c o n t a i n e r s i n v o l v i n g l a r g e r amounts of material i n an e f f o r t t o g e n e r a t e , i d e n t i f y and characterize p o s s f b l e uranium oxyearbide phases or other s o l i d mixed-composition phases. S e v e r a l a n a l y t i c a l t o o l s w i l l b e used t o c h a r a c t e r i z e t h e isolated phases, such as x-ray d i f f r a c t i o n , chemical a n a l y s i s , p e t r o g a p h y and metallography.

5-37

.... & !e,

5.5

TASK G R O W 4 . 2

5.5.1

Objective

C O O W T SALT CHEMISTRY

The o b j e c t i v e sf t h i s t a s k group i s t o develop an understanding of t h e chemical parameters of t h e c o o l a n t . P a r t i c u l a r emphasis w i l l be given t o t r i t i u m t r a p p i n g and c o r r o s i o n r e a c t i o n s . This portion of t h e program p l a n i s complicated by t h e p o s s i b l e s e l e c t i o n of an a l t e r n a t e c ~ o l a i~n~ t p l a c e of f l u o r o b o r a t e . If t h a t QCCULS, t h e program p l a n must be changed f n l i g h t of t h e r e s e a r c h needed f o r the new coolant.

5.5 2 e

Schedule

The s c h e d u l e f o r W Q P ~ i n t h i s t a s k group is g i v e n i n Table 5.5.2.

5 5 3 D

Funding

The o p e r a t i n g fund requirements f o r this task group are summarized i n Table 5.5.3.1, and t h e c a p i t a l equipment fund requirements a r e summarized i n Table 5.5.3.2.

5.5.4

Facilities

N o s p e c i a l f a c i l i t i e s are needed f a r t h i s r e s e a r c h . i n Building 4500s are adequate.

5.5.5

Task 4.2.3.

Existing laboratories

Oxide and hydroxide chemistry of f l u o r o b o r a t e

athe p r e s e n c e of oxide and hydroxide s p e c i e s i n NaBF4-NaF (92-8 m l e 21, even in l o w eensentrations, will have effects on C O T X Q S ~ O X I of the

.:&

B a s t e l l a y Es and on r e a c t i o n s w i t h tritium. A t h i g h e r c o n c e n t r a t i o n s , as would occur i f steam l e a k e d i n t o t h e cookant c i r c u i t , more e x t e n s i v e CQTXOSiOn Would OCCUr; Eiddi%iQXX,t h e Vapor Over t h e COo$ant Would change from dl BFZJ ts vapor s p e c i e s a l s o c o n t a i n i n g hydrogen a d oxygen. The h y d r o g e ~ - c ~ n t a i ~ l i snp g e c k s may b e important i n s p a r g i n g t r i t i u m o u t of the c o o l a n t c i r c u i t . The e x p e r i m e n t a l e f f o r t s of t h e past' have b a r e l y begun t o e l u c i d a t e t h e i m p o r t a n t , but complex, chemi s t v Qf these Species

.... .... : :A

It i s clear t h a t a much TLEOR complete understanding of oxide and h y d ~ o x i d e s p e c i e s w i l l have t o b e achieved b e f o r e t h e s e s p e c i e s can b e employed i n schemes t o c o n t r o l t r i t i u m m i g r a t i o n , before C O K X - ~ S ~ can Q ~ be a c c u r a t e l y p r e d i c t e d , o r f l u o r o b s r a t e produced at t h e r e q u i r e d p u r i t y .

Table

5.5.2.

ScheduPe

far

work

in Task Group

4.2

-Coolant Fiscal

1975 4.2.1

oxide and hydraxide chemistry of fluoroborate 4.2.1.1 Identjification of oxidecontaining species 4.2.1.2 Reactions of Hz0 with NaBF4 4.2.1.3 Tritim trapping in fluoroborate

4.2.2

Corrosion 4.2.2.1 4.2.2.2

chemistry of fluoroborate Free energy of formation of corrosion products Boride formation

Coolant 4.2.3.1 4.2.3,2

purification Inftlal In-reactor

4.2.4

Alternate 4.2.4.1 4.2.4.2

coolant evaluation Interim report Final evaluation

4.2.5

Physical coolants 4.2.5.1 4.2.5.2 4.2.5.3

property

4.2.3

4.2.5.4

purification purification

determinations

Thermal conductivity Surface tension Solubility of corrosion product5 Qther physical properties of fluoroborate and alternate coolants

salt

chemistry

year 1982

Table 5.5.3.1.

Operating fund requirements f o r Task Group 4.2 - Coolant salt chemistry ( c o s t s i n 1000 d o l l a r s ) F i s c a l year ~~

4.2.1

Oxide and hydroxide chemistry of f l u o r o b o r a t e 4.2.1.1 I d e n t i f i c a t i o n of oxidecontaining s p e c i e s 4.2.1.2 Reactions of H28 w i t h NaBF4 4.2.1.3 T r i t i u m trapping i n f luoroborate S u b t o t a l 4.2.1.

4.2.2

Corrosion chemistry of fluoroborate 4.2.2.1 Free energy of formation of c o r r o s i o n products 4.2.2.2 Boride formation S u b t o t a l 4.2.2

4.2.3’ Coola n t pur if ic a t i o n 4.2.3.1 I n i t i a l p u r i f i c a t i o n 4.2.3.2 In-reactor p u r i f i c a t i o n S u b t o t a l 4.2.3

1975

1976

1977

1978

1979

l98Q

138

140

155

173

160

50 25

1981

1982

1983

190

155

175

190

155

70 -.

1985

110

I _

1984

1986

Table 5.5.3.1

1975

4.2.4

ABternate

coolant

4.2.4.1 4.2.4.2

Interim repart Final evaluation

1977

1978

1979

Fiscal

year

1980

a981

1982

1983

20 30

50 -50

30 30

1Q 10

pkOdl.EtS

Qther pbysica~ properties of fluoroborate and alternate coolants Subtotal

4.2.5 -

operating

funds

for Task Group 4.2

_ I

3Q 165

18Q

180

218

220

_ 1 _

65 -

270

15Q -

335

10 -

Total.

1985

Physical pmperty determimtions on coolanta 4.2.5-l Thermal conductivity 4.2.5.2 Surface tensian 4.2.5.3 Solubilkty of cormslon 4.2.5.4

1984

evaluation

Subtotaal 4.2.4 4.i.5

1976

(continued)

360

55 -

220

aaa

1986

Table

4.2.1

4.2.2

4.2.3

4.2.5

5.5.3.2.

Capital

equipment

.fund requirements far Task Group 4.2 - Coolant (costs in 1QQQ dollars)

Oxide and hydroxide chemistry of fluoroborate 4.2.1.1 Identification of oxidecontaining species 4.2.1.2 Reactions of &$I with NaBF4 Tritium trapping in fluoroborate 4.2.1.3 Subtotal

4.2.1

Corrosion 4.2.2.1 4.2.2.2

chemistry of fluoroborate Free energy of formation corrosion products Boride formation

Subtotal

4.2.2

CQolant 4.2.3.1 4.2.3.2

purification Initial purification In-reactor purification

Subtotal

4.2.3

Phyysical coolante 4.2.5.1 4.2.5.2 4.2.5.3

property

determinations

Thermal conductivity Surface tension Solubility of corrosion

20 15

20 18 75

105

5 5

11Q

5 10 75 90

salt

chemistry

Fiscal

year

5Q 50

10 1Q

5 -

50 -

10 -

20 6Q 5

products

Table

1975 4.2.5.4

SubtQtal Total

capital.

Other physical. properties fluoraborate and aPternate cocPlants

funds

for

1976

(cantimed)

1977

1978

Fiscal

year

1979

1980

198.l

f982

10 22

25 xl 75

10 95

1983

4.2.5 equipment

5.5.3.2

Task Grasp 4-2

11Q

145

30 40

1984

5-43

5.5.5.1 .... :H

... ..... ..... :.x*

.:..... : x,

.... ....

Subtask 4.2.1.1

I d e n t i f i c a t i o n of oxide-containing species

The chemical formula and s t r u c t u r e of o x i d e and hydroxide s p e c i e s b o t h i n t h e m e l t and i n t h e vapor are v i t a l i n f o r m a t i o n t h a t w i l l b e a p p l i e d t o t h e p r a c t i c a l problems of c o r r o s i o n , tritium c o n t r o l and i m p u r i t y removal i n f l u o m b o r a t e c o o l a n t e

Tkle i o n BP30H- h a s been p o s i t i v e l y i d e n t i f i e d i n f l u o r o b o r a t e c o o l a n t from measurements of i t s i n f r a r e d a b s o r p t i o n spectrum. 33 This s p e c i e s i n low c o n c e n t r a t i o n a t 425"C, i s a p p a r e n t l y s t a b l e f o r a few days. I n f r a r e d s t u d y of t h e m e l t s s u g g e s t s t h a t one o r more a d d i t i o n a l oxygenc o n t a i n i n g s p e c i e s are a l s o p r e s e n t . 3 3 S o l i d NaBF3OH h a s been t o undergo a b5molecular condensation r e a c t i o n a t 100-128°C t o y i e l d H,O(g) and Ma2B2F60. The s a m e paper n o t e s t h a t , a t 2 4 0 " C , Na2232F60 d i s p r o p o r t i o n a t e 8 i n t o Na3B3P603 and NaBF4. It i s p o s s i b l e t h a t t h e s e o x i d e s may e x i s t i n molten f l u o r o b o r a t e .

~.:<K

These complex o x i d e s a l o n g w i t h some o t h e r r e l a t e d compounds w i l l b e s y n t h e s i z e d f o r t h e purposes of "finger p r i n t i n g " (by i n f r a r e d , "R, and o t h e r t e c h n i q u e s ) and t o s t u d y t h e i r d i s s o l u t i o n and v o l a t i l i z a t i o n b e h a v i o r i n molten f l u o r o b o r a t e . The compounds t o b e p r e p a r e d w i l l i n c l u d e Na2B2F66, Na3B3F603, N~~B~FL$~(OH),BP,eH20, BP3°2Ha0, BP20H and BF20H*H28. T h i s l i s t i s n e c e s s a r i l y t e n t a t i v e because i n v e s t i g a t i o n s of r e a c t i v i t y and v o l a t i l i z a t i o n may d e c r e a s e ( o r p o s s i b l y i n c r e a s e ) t h e number of s i g n i f i c a n t s p e c i e s i n molten f l u o r o b o r a t e o r i t s vapor. Nuclear magnetic resonance ( p r o t o n , f l u o r i n e , b o r o n - l l ) w i l l be t h e primary too% by which v o l a t i l e s p e c i e s w i l l b e i d e n t i f i e d . Infrared absorption s p e c t ~ ~ i w i l l b e used f o r i d e n t i f y i n g s p e c i e s i n t h e s o l i d o r l i q u i d s t a t e s .

5.5.5.2

Subtask 4.2.1.2

Reaction of H 2 8 w i t h NaBP4

Hydrolysis e q u i l i b r i a , t h e s i m p l e s t of which may b e w r i t t e n as H20(g) NaBFq(d) = NaBF3QH(d) 4- HP(g), are p a r t i c u l a r l y i m p o r t a n t i n a s s e s s i n g C O ~ W S ~ O R , i n d e v i s i n g tritium c o n t r o l schemes, a d i n c o ~ l a n t p u r i f i c a t i o n . Study of t h e s e e q u i l i b r i a i s hampered by t h e p r e s e n c e of gaseous BF3 and B-0-F compounds and p o s s i b l y by condensation of NaBP30H i n t o one o r more complex o x i d e s . N e v e r t h e l e s s , f l u o r o b o r a t e s have been p u r i f i e d t o some e x t e n t by s p a r g i n g w i t h gaseous m i x t u r e s of HF and ~ ~ 3 , ?t h 9 e l a t t e r s e r v i n g to m a i n t a i n t h e composition sf t h e melt. me l i m i t e d s u c c e s s 0% t h i s procedure s u g g e s t s t h a t t h e r e v e r s e of t h e above r e a c t i o n may b e used f o r i n i t i a l p u r i f i c a t i o n of f l u o r o b s r a t e i f vendors cannot &upply a d e q u a t e l y p u r i f i e d material ( s e e Task 4 2 . 3 )

..&

..:&

,.;.A

..'.?,

... .... ..... ..,m

Hydrolya is e q u i l i b r i a w i l l b e i n v e s t i g a t e d i n p a r a l l e l w i t h t h e s y n t h e s i s Compositisn of s o l i d , and i d e n t i f i c a t i o n e f f o r t s (see Subtask 4.2.1.1). l i q u i d and vapor phases w i l l b e s t u d i e d a t MSBR o p e r a t i n g t e m p e r a t u r e s , depending p r i m a r i l y , b u t n o t e x c l u s i v e l y , upon chemical a n a l y s i s and upon infrared and "R spectra.

5-44

%.5.5,3

Subtask 4 . 2 . 1 . 3

'Eriti~ trapping in %luoroboroate

An important development o b j e c t i v e i n t h e BevePopment of m o l t e n - s a l t r e a c t o r s ( c o n v e r t e r s as w e l l as b r e e d e r s ) Fs to p r e v e n t aS.1, o r v i r t u a l l y

a l l , of the tritium which d i f f u s e s into the c o o l a n t c i r c u i t from r e a c h i n g t h e steam system. The f l u o r o b o r a t e coolant o f f e r s a reasenable p o t e n t i a l for meeting t h i s o b j e c t i v e t l r r ~ u g htwo t y p e s of chemical r e a c t i o n o x i d a t i o n and i s s t o p e exchange. ~nitiakattempts80 to exchange deuterium f o r the pretium i n the i o n i c s p e c i e s B F 3 D " w e r e n o t s u c c e s s f u l . I n s t e a d , BF3OB- formed Ln the m e l t ; this r e s u l t s u g g e s t e d that oxidation (by s t r u c t u r a l metal ions) of deuter5um o c c u r r e d r a t h e r than i s o t o p e exchange. By i n f e r e n c e , then, oxidation of t r i t i u m nay b e the nore f r u i t f u l l p a t h toward t r a p p i n g t r i t i u m i n the coolant. The reaction 112 H2(g> -4- 8%"

+ 0'-

= Ni(al%oy)

+ OH-

will be s t u d i e d i n a s y s t e m a t i c f a s h i o n . Tritium rereoval schemes v i a complex v o l a t i l e s p e c i e s w i l l b e i n v e s t i g a t e d a f t e r s u f f i c i e n t information has been o b t a i n e d about these s p e c i e s (Subtasks 4 . 2 . 1 . 1 and 4 . 2 . l . 2 ) .

If oxidation r e a c t i o n s can s u c c e s s f u l l y l e a d to t r a p p i n g of tritium i n f l u o r o b o r a t e c o o l a n t , i t will s t i l l be n e c e s s a r y t o p r o c e s s t h e c o o l a n t f o r removal of the tritium. Reaction w i t h CP4 may b e e f f e c t i v e i n t h i s regard. Study of t h e reaction

would follow t h e demonstrated c a p a b i l i t y of u s i n g CF4 Tn p u r i f i c a t i o n t h e coolant (see S u b t a s k 4.2 3 .a)

5.5.6

5.5.6.1

Task 4 . 2 . 2

C o r ~ o s i o nchemistry of f l u s r o b o r a t e

Subtask 4 . 2 . 2 . 1

Free energy o f formation of c o r r o s i o n p r o d u c t s

The chemical nature of t h e coolant will be a s i g n i f i c a n t f a c t o r i n f i x i n g the form and stability of t h e containment metals t h a t are oxidized ( i e e e 2 corroded) d u r i n g reactor o p e r a t i o n s . With f l u o ~ ~ b ~ r caotoel a n t s a l t s , SOP and c a p s u l e experiments have s h o r n t h a t ~ i 2 +F&+, ~ and cr3* i o n s are s l i g h t l y s o l u b l e c o r r o s i o n p r o d u c t s . When the s o l u b i l i t y l i m i t sf these ions is exceeded, t h e y p r e c i p i t a t e as i o n i c complex cornpounds MaNfF3, NaFePg, N a q C r F g . free e n e r g i e s of formation (AGT) of these compounds must be b o r n n o t only t o c h a r a c t e r i z e the e x t e n t of c o r r o s i o n i n f l u o r s b o r a t e s , b u t a l s o t o p r e d i c t what redox r e a c t i o n s are l i k e l y t o reverse o r counter t h e m e t a l o x i d a t i o n . The f r e e e n e r g i e s of formation of tb'aNiF3 and NaFeP3 have a l r e a d y been publishedeas Experiments are U E I ~ ~ I W Eto X ~ o b t a i n AGO of N z I ~ C ~by F ~E E ~ B S of the ' t " e a c t i ~ n , f

5-45

It should be noted that the chemical fornula and srability of chromfm, nickel and iron corrosion p r o d u c t s formed in other MaP-containing coolants may be similar to those which f o m in fkaaorobsrate coolant. Since t i t a n i m is a significant constituent of MSBR c s n t a i m e n t alloys, the corrosion t h e a m o d p a i c s of titanium in the coolant wfll a l s o be studied This includes investigations of the s t a b i l i t y of trivalent t i t a n i m and sf the existence and solubility of Na3TiPgr NaTPP4 or other complex s a l t s .

5.5.6.2

Subtask 4.2.2.2

Boride fornation

B O K O P ~in fluorsbsrate coolant may possibly o x i d i z e constituents of t h e containment alloys such that reduced b ~ r may ~ n deposit OR metal surfaces. Two exmpkes of such p o s s i b l e reactions with negative standard free energy

changes are:

(The latter reaction may lead to Na3TiP6, whose fOTXMtiQn free energy If boron deposition should occur in MSBR p r i m a r y heat-exchangers and if the d i f f u s i v i t y of the boron in H a s t e l l o y N is sufficiently high, embrittlement of the Hastelht resule: via helium produced by delayed neutrons in the reaction L i e Olb the other hand, if the deposited B%orOn KCiRlained On t h e metal surface, radiation damage would be of little consequence. Thus, as long as flusroborate is a candidate coolant f o breeder ~ reactors, it is necessary % Q Bnvestigate boride formation and diffusion in metals used 5n t h e primary heat exchangers.

&PI be investigated under Subtask 4.2.2.1).

Initial C Z X ~ ~ K ~ I I X X I of ~ S boride formation on Hastelloy %a and other alloys will be carried out: ~ 5 t hs p e c h e n s in contact with NaBFh-MaF (92-8 mole X ) f o r times varying between two weeks and six months; the specimens tail1 be analyzed for boron penetration. If these r e s ~ l t si n d i c a t e significant penetration of boron i n t o metal specisaens, accurate deterIKhatiOnS 0% bOroll d i f f U s i Q l l rates k&11be caKKi@d out.

... ..... <.x.>

5-46 5.5.7

Task 4.2.3

5.5.7.1

Coolant p u r i f i c a t i o n

Subtask 4.2.3.1

Initial p u r i f i c a t i o n

It i s h o r n from l o o p t e s t s t h a t d e l i b e r a t e a d d i t i o n of water, even in r a t h e r m a l l q u a n t i t i e s , w i l l amplify the c o r r o s i v i t y of f l u o r o b o r a t e coolant.33 I t i s , t h e r e f o r e , n e c e s s a r y f o r the salt t o be as d r y as p r a c t i c a b l e . C m e r c i a l l y a v a i l a b l e NaBP4, when r e c r y s t a l l i z e d from dilute aqueous El?, can be p u r i f i e d t o c o n c e n t r a t i o n s as PSW as 4 ppm i n p r o t o n s and 208 ppa i n s ~ i d e . Other ~ ~ i m p u r i t i e s t h a t cause c o r r ~ s i o ~ l are metallic ions, notably f e r r o u s or f e r r i c i o n s ; t h e s e may be i n t r o d u c e d t n t a c m e r c i a l NaBP4 when s t e e l equipment i s used i n the s a l t p r e p a r a t i o n . It is a l s o n e c e s s a r y t o guard a g a i n s t t h e i n t r o d u c t i o n of i m p u r i t i e s such as c o b a l t which would be e a s i l y a c t i v a t e d by delayed n e u t r o n s i n t h e primary heat-exchangers. There i s a need t o c o n t a c t and work w i t h a vendor (presumably Harshaw) t o determine how t h e bench-scale p u r i f i c a t i o n can be sealed-up and how harmful m e t a l l i c i o n s can be e i t h e r k e p t o u t or minimized i n the d e l i v e r e d product. I f t h e vendor cannot supply an a d e q u a t e l y p u r i f i e d material, a p p l i c a t i o n of t h e HF(g) f BF3 (8) s p a r g i n g method should be s t r o n g l y considered (see Subtask 4 . 2 . 1 . 2 ) .

During the l i f e of an HSBR t h e r e i s a f i n i t e p r o b a b i l i t y t h a t a s t e m leak w i l l occur and t h a t i t w i l l be n e c e s s a r y t o p r o c e s s t h e c o o l a n t fop. p r o t ~ nremoval and p o s s i b l y t o Power t h e o x i d e c o n c e n t r a t i o n . Corrosion w i l l have t o be k e p t a t a Pow l e v e l t o p r e v e n t e n t r a i n e d s o l i d s (like Ma3CrP6) from c l o g g i n g c o o l a n t passages i n s t e m genera t o r s and h e a t exchangers. Accurate s o l u b i l i t i e s of c o r r s s i o n product n S e c t i o n 5.5.9.3, Subtask 4.2.5.3). Practical i o n s should be E s n ~ ~(see on-line p u r i f i c a t i o n as w e l l as tritium repnoval p r o b a b l y involves des i g n i n g by-pass f a c i l i t i e s (such as a c o o l a n t d r a i n t a n k l i n e d w i t h g r a p h i t e ) where one o r more p r o c e s s i n g o p e ~ a t i o n scan be c a r r i e d out. A possible method f o r removing o x i d e and p r o t o n s ( t r i t o n s ) from t h e c o o l a n t i n v o l v e s r e a c t i o n s with CF4:

$-(a)

+ 1 6 2 CF&)

~ b ca o 2 ( g ) + a F ( d >

sa--(sl>4- l/2 CFL+(g>= 1 / 2 eo.&>

t P-

(ea) 4- mcg> .

P r e l i m i n a r y experiments85 f a i l e d t o i d e n t i f y C O ~as a r e a c t i o n product, b u t t h i s may have been due t o d i f f i c u l t i e s i n a n a l y z i n g a complicated e f f l u e n t g a s stream c o n t a i n i n g HI?, H20, BP3, @02 and u ~ ~ e a c t e CF4. kl A combination of gas chromatographic, mass-spectrographic and b f r a r e d analytical methods should solve t h e s e d i f f i c u l t i e s . Experimental work would focus on t h e e q u i l i b r i u m a s p e c t s of t h e above r e a c t i o n s . However, s t u d i e s sf c a t a l y s i s may be n e c e s s a r y should t h e s e r e a c t i o n s prove t o proceed s1ow1y.

5-47

Task 4.2.4

5.5.8

Alternate coolant evaluation

Although i t now a p p e a r s t h a t t h e f l u s r o b o r a t e c o o l a ~ t ,NaBP4-NaF (92-8 mole X I , can b e u t i l i z e d in a n MSBR system w i t h s u i t a b l e compromise of d e s i g n parameters and p r e v i o u s c o n s i d e r a t i o n s of a l t e r n a t e c o o l a n t s have n o t r e v e a l e d a more i d e a l c o o l a n t , i t w a s deemed d e s i r a b l e t o make a r e e v a l u a t i o n of t h e c o o l a n t s e l e c t i o n . Less t h a n i d e a l a t t r i b u t e s of t h e f l u o r o b o r a t e a r e i t s h i g h m e l t i n g p o i n t and c o r r o s i v i t y toward HastePloy N upon t h e a d d i t i o n of m o i s t u r e . Experimentally u n ~ e s o l v e d a s p e c t s i n c l u d e c o m p a t i b i l i t y w i t h f u e l s a l t and tritium t r a p p i n g . T h e r e f o r e , a l t e r n a t e c o o l a n t s w i l l be e v a l u a t e d .

5.5.8.1

Subtask 4.2.4.1

Interim report

En t h i s i n v e s t i g a t i o n , f l u o r o b o r a t e and o t h e r f l u i d s w i l l be e v a l u a t e d i n terms of t h e c o n s t r a i n t s and requirements imposed upon t h e c o o l a n t of an MSBR. Nine g e n e r a l a t t r i b u t e s ( c o n s t r a i n t s and requirements) have been i d e n t i f i e d :

The consequences of a c c i d e n t a l mixing of c o o l a n t and f u e l must be minimal and r e v e r s i b l e .

I t i s h i g h l y d e s i r a b l e t h a t t h e c o o l a n t should s e q u e s t e r v i r t u a k l y a l l tritium d i f f u s i n g i n t o t h e c o o l a n t c i r c u i t .

The c o o l a n t must be CQmpatibk? w i t h components which i t c o n t a e t s normally e

Leaks i n t h e s t e m - r a i s i n g system must be t o l e r a b l e

R a d i a t i o n w i t h i n t h e primary heat-exchanger should have winimaI d e t r i m e n t a l e f f e c t s upon t h e vapor p r e s s u r e , c o m p ~ s i t i ~and n c o m p a t i b i l i t y of t h e c o o l a n t .

The c o o l a n t should have a c c e p t a b l e h e a t - t r a n s f e r and f l u i J p r o p e r t i e s ; t h e p r o p e r t i e s of t h e c o o l a n t should n o t n e c e s s i t a t e a g r e a t l y increased f u e l inventory, thereby lessening the breeding performance of t h e r e a c t o r .

The c o o l a n t should have a f r e e z i n g p o i n t below 600'F.

The c o o l a n t should e x h i b i t a low vapor p r e s s u r e a t normal o p e r a t i n g temperatures e

The c o o l a n t should be i n e x p e n s i v e and a v a i l a b l e i~ h i g h p u r i t y .

An in-depth e v a l u a t i o n of p o t e n t i a l c o o l a n t s i s underway.

S i n c e it i s p o s s i b l e t h a t a s i n g l e c ~ o l a n tmay n o t f i l l a l l t h e requirements of an MSBR, c o n s i d e r a t i o n w i l l a l s o be given t o two-coolant l o s p s . 7 A draft r e p o r t w i l l be prepared and c i r c u l a t e d f o r comment. Comments w i l l be d i s c u s s e d and i n c o r p o r a t e d i n t o a f i n a l r e p o r t .

5-48

5.5.8.2

Subtask 4.2.4.2

Final evaluation

The r e s u l t s of t h e previous s u b t a s k will include recommendations f o r l a b o r a t o r y experiments. The ~ e s u l t sof these e ~ p e ~ h e n twsi l l have an important b e a r i n g on t h e ultimate s e l e c t i o n of t h e coolant. When t h e coolant evaluation is completed, a final r e p o r t containing the results and recommendations will be i s s u e d

5.5.9

Task 4.2.5

Physical property determinations on coolants

The number of measurements and general effort r e q u i r e d will depend, to some extent, upon t h e coolant chosen on the b a s i s of the assessment ask 4 2 4 ) currently unitemay ~ i s c c s s i t y29 d e n s i t y , 29 and heat N~BF~-RP (92-8 ~ F mole Z > are known w i t h sufficient accucapacity86 racy f o r most purposes. a

5.5.9.l

Subtask 4.2.5.1

'%hemal conductivity

If NaBFb-NaF (92-8 m l e %> is the u l t h n a t e se%eetion as t h e coolant, its tkemal c o n d u c t i v i t y shouP b e determined w i t h h i g h e r precision than previously reported.87 The apparatus should be the same as that used f o r determining thermal conductivity of the f u e l salt ( s e e 5 4 9 E Sub task e

'4.l.5.1) 5.5.9.2

Subtask 4 . 2 . 5 . 2

Surface tension

5.5.9.3

In o r d e r t o p r o p e r l y assess t h e consequences of corrosion by t h e c o o l a n t , i t i s n e c e s s a r y t o have an adequate d a t a b a s e . Corrosisn-product solubility as a function of temperature is an inzegralb component of the d a t a base. In f l u s r o b o r a t e coolant, the s o l u b i l i t y of NasCrF6 (a I X K ~ O S ~ Q T I p ~ o d u e to b s e m e d in ~ i r t ~ a l l ll loop ~ tests) has been measured. HOWever, the r e p o r t e d data34 were quite scattered in the range 4 5 0 - 5 5 0 " ~ ; also, the data were o b t a i n e d at Lower NaF ~ ~ n ~ e w t r ~ ithan t i ~ would ns be used in the f l u o r s b o r a t e coolant. Since removal of Na36rFg would be i 9 n p o ~ t a n tin any c~olantl o o p containing G B ~ o r o b ~ r a t eit , would be useful t o determine more accurately t h e solubilities of Na3CrPg in Ea (92-8 mole XI. Once c s r r o s i o n of chromim becomes limited by d i f f u s i o n within H a s t e l l o y N , structural m e t a l csrrosisn in f l u s r o b o r a t e becomes t h e oxidation 0% n i c k e l ; the CO%k-osion p r o d u c t , N a N i P 3 , Wb%% p r e c i p i t a t e when the coolant is saturated with ~ i z + accordingly ~ s o l u b i l i t y measureEJA%ntSof NaNiP3 flUOKObOr%te a%-eVeri d e S i r % b l e .

5-49 5.5.9.4

Subtask 4.2.5.4 Other p h y s i c a l p r o p e r t i e s of f l u o r o b o r a t e and a l t e r n a t e coolants

I f an a l t e r n a t e c o o l a n t i s chosen, p h y s i c a l p r o p e r t i e s would b e determined as r e q u i r e d . FOP i n s t a n c e , if a BeF2-containing salt w e r e the c a n d i d a t e , t h e v i s s o s i t y should probably b e measured. I f f l u o r o b s r a t e i s r e t a i n e d as c o o l a n t , t h e d e n s i t y change upon m e l t i n g should b e measured. This i n f o r m a t i o n i s probably n e c e s s a r y i n o r d e r t o p r e d i c t stresses t h a t may occur i n t h e s t e a m - r a i s i n g system, assuming some of the c ~ o l a n ti s allowed to f r e e z e on b a f f l e plates, e t c .

5.6

TASK GROUP 4 . 3

5.6,l

Objective

TRITIUM B E U V I Q R

The o b j e c t i v e of this t a s k group i s to o b t a i n t h e data and develop t h e technology n e c e s s a r y to l i m i t t o a c c e p t a b l e levels t h e rate a t which t r i t i u m i s r e l e a s e d from m o l t e n - s a l t r e a c t o r s .

The n e c e s s a r y d a t a i n c l u d e p e m e a b i l i t i e s , s o l u b i l i t i e s , and d i f f u s i v i t i e s of tritium, b o t h pure and mixed w i t h o t h e r hydrogen i s o t o p e s , i n s a l t s and metals, and i n f o m a t i o n on e q u i l i b r i a and r e a c t i o n s between t r i t i u m and materials p r e s e n t i n an MSBR. A m j o r o b j e c t i v e i s to determine whether an o x i d e f i l m can b e formed on t h e stem s i d e of t h e steam generator which w i l l s i g n i f i c a n t l y reduce t h e t r i t i u m permeation

rate.

5 6 2 D

..... ,.w,

... .....

Schedule

The s c h e d u l e f o r work i n t h i s t a s k group i s given i n Table 5.6.2. 5e 6e 3

Funding

.:.YL.

The o p e r a t i n g fund ~ e q u i r e m e n t sf o r t h i s task group are sumwarized i n Table 5.6.3.1, and t h e c a p i t a l equipment fund P ~ C ~ ~ P W I ~are X I ~ summarized S i n Tab2.e 5.6.3.2.

5.6.4

<-;

Facilities

C o n s t r u c t i o n of a h i g h - p r e s s u r e , high-tempe~ature steam loop t e s t f a c i l i t y may be r e q u i r e d as p a r t of the s t u d y of 5xfde s t a b i l i t y i n steam system, Subtask 4.3.1.2. ThFs major f a c i l i t y would permit s t u d i e s t o b e made of t h e s o l u b i l i t i e s , t r a n s p o r t , and Long-term e f f e c t i v e n e s s of oxide f i l m as tritium barriers. Control of the s t e m chemistry and c a p a b i l i t y of h a n d l i n g t r i t i u m could be achieved i n t h e f a c i l i t y . Both permeation rates and chemical changes of oxides w i t h t i m e could be studied. The f a c i l i t y w o d d c o s t approximately $208,800 and would r e q u i r e approximately two y e a r s f o r d e s i g n and c o n s t r u c t i o n .

Table

S-6.2.

Scbedde

for

worb

in Task Graup

4.3 - Trikim Fiscal

4.a.1

Pemeatiwn 4.3.1.1 4.3.1.2

4.3.2

Solubility species

4.3.2.1 4.3.2.2 4.%.2.%

4.3.3

Equilibria containing sya terns 4.3.3.1 4.P.3.2

studies Pemeatiwn of clean oxidized metals zxabl.l.ity of oxides steam systems

and in

of tritium-containing in nmlten salts Solubility of krikim fue.8 salt Sdubility of kritfum coolant salt Solubiliky af krltfum fluoride in fuel sdt between tritium

imparkank in salt-gas

in in

species

Fuel salt equilibria Coolant salt equilibria

4.3.4

Isotopic exchange bekween tritim and chemhl3.y bwund hydrogen

4.3.5

IT corrosion aedvity

behavior

low TF

behavfws year

Table

5.6.2

(cantinued) Fiscal

19 76 4.3.6

Diffusfvity 4.3.6.1 4.3.6.2 4.3.6.3 4.3.6.4

studies Diffusivity af in fuel salt Diffusivity of coolant salt Diffusivity of in fuel salt Diffusivity of in coolant salt of

tritium resctors

HT and H2 tritdum

HP and TF HI? and TF

4.3.7

Modeling molten-salt

behatior

4.3.8

Trftium absorption on carbon in contact with the coolant

year

1981

Table 5.6.3.1.

4.3.1

Pemeation studies 4.3.1.1 Permeation of clean and oxidized metals 4.3.1.2 Stabbility of axides in steam system Subtotal

4.3.2

---7-55

180

110

165

125

11Q

110

165

125

55 55

55 __---55 110

110

55 55

55 5%

25 25

4.3.3

behador

fluoride

4.3.2

Isotopic exchange between tritlm chemically bound hydrogen

fund requirements of Task Group 4.3 - Tritium (costs in BQQQdollars)

Equilibria between important species containing trftim in salt-gas systems 4.3.3.1 Fuel salt equilfbria 4.3.3.2 Caolant salt equilibria Subtotal

4,3,4

4.3.1.

Solubilfty of tsitim-containin& qaecies in mlten salts 4.3.2.1 Solubility of tritium fuel 5dt 4.3.2.2 Solubility of tritim coolant salt 4.3.2.3 Solubility of trbtlum in fuel salt Subtotal

4.3.3

operating

_s 55

55 30 85

50 55

105

and

pi., ......

p:, s.:.

Table 5.6.3.1

(continued) F i s c a l year

1975 4.3.5

1976

1977

1978

1979

1980

1981

TF corrosion behavior a t Bow TF activity

4.3.6.1 4.3.6.2 4.3.6.3 4.3.6.4

D i f f u s i v i t y of HT and H2 i n f u e l salt D i f f u s i v i t y of t r i t i u m i n coolant s a l t D i f f u s i v i t y of HF and TF in fuel s a l t D i f f u s i v i t y of HF and TF i n coolant s a l t

4.3.8

1984

Modeling of tritium behavior in molten-salt r e a c t o r s

1985

110

1986

135

200

240

T r i t i u m absorption on carbon i n contact wfth t h e coolant

25 -

Total operating f m d s f o r Task Group 4.3

1983

Subtotal 4 . 3 . 6

4.3.7

1982

105

165

220

270

325

35 _

515

550

365

275

cn w

Table

4.3.1

Permeation 4.3.1.1 4.3.1.2

4.3.2

studies Permeation of clean oxidized metals Stability of oxides steam systems 4.3.1

Solubility species 4.3.2.1

of tritium-containing in molten salts Solubility af trftium fuel salt Solubllity of tritium coolant salt Solubility of tritium fluoride in fuel salt

4.3.2.3

4.3.4

Capital

Subtotal

4.3.2.2

4.3,3

5.6.3.2.

Subtotal

4.3.2

Equilibria species salt-gas 4.3.3.1 4.3.3.2

between important containing tritium in systems Fuel salt equilibria Coolant salt equilibria

Subtotal

4.3.3

equipment

fund requirements for (costs in mm doawx.)

1977

Task

Group

4.3

Fiscal

year

198Q

198-l.

1982

1983

50 5Q

10 10

5 5

2 4

1975

1976

2 16

30 34

15Q 15Q

1978

1979

- Tritium

behavior

1984

1985

and in

Isotopic exchange between tritium and chemically bound hydrogen

in in

12 1s

5 8

2 4 6

2 2 4

2 2

1986

Table 5.6.3.2

(continued) Fiscal year

1975 4.3.5 4 3.6

1976

I977

1978

1979

1980

1981

1982

TF corrosion behavior a t Pow TF activity

Dif f u s i v i t y studies 4.3.6,l D i ffu s i v i ty of HT and Hp i n f u e l salt 4.3.6.2 D i ffu s i v i ty of tritium i n coolant s a l t 4.3.6.3 D i ffu s i v i ty of HF and TF i n fuel s a l t D i ffu s i v i ty o f HF and TF 4.3.6.4 i n coolant s a l t Subtotal 4.3.6

Total

1983

1984

5 8

1986

5 5

1985

2 2

157

asl I

5-56

5.6.5

5.6.5.1

Task 4.3.1

Perneation studies

Subtask 4.3.1.1

&,....

Perneation of clean and oxided metals

M e a s u r m e n t s w i l l be made of the rate a t which tritium permeates candid a t e s t r u c t u r a l and stem g e n e r a t o r materials i n c o n t a c t with g a s of c o n t r o l l e d dewpoint and hydrogen c o n t e n t . P r e c i s e measurements w i l l be made u s i n g t r i t i u m as pemeant in t h e p r e s e n c e of an excess of hydrogen h Order to IBinhkZ.e t P a n s i e n t and Wall C2ffect.S. S t u d i e s w i l l be c a r r i e d o u t t o determine the range of a l l o y compositions which w i l l f o m u s e f u l tritium permeation b a r r i e r s on p o t e n t i a l s t e m g e n e r a t o r materials when o x i d i z e d by s u p e r c r i t i c a l s t e m . I n i t i a l work will include the esnstruction of the a p p r o p r i a t e a p p a r a t u s and, t h e n , measuring permeation through d e a n s t r u c t ~ r a lalloys and through c a n d i d a t e steam g e n e r a t a r a l l o y s u s h g steam having a dewpoint below E8Q0C. Oxides obtained on t h e p o t e n t i a l l y u s e f u l materials w i l l be analyzed by Auger and ESCA methods and compared w i t h o x i d e s formed w i t h other t h e - t e m p e r a t u r e h i s t o r i e s . These l a t t e r oxides would be prepared in a s e p a r a t e f a c i l i t y - a n o x i d a t i o n test s t a n d . Subsequent work i n this s u b t a s k w i l l involve a d d i t i o n a l s c r e e n i n g tests f o r c a n d i d a t e s t e m g m e r a t o ~materials and d e t e r m i n a t i o n of long-term changes i n a i d e composition and s t r u c t u r e .

5.6.5.2

Subtask 4.3.1.2

S t a b i l i t y of o x i d e s in stem systems

Work in t h i s s u b t a s k 5s concerned with de%@KIlliRatiQI? of t h e chemical form, s t a b i l i t y , and long-tern e f f e c t i v e n e s s i n r e t a r d i n g tritium g e r meation of o x i d e f i l m s f ~ m e don p o t e n t i a l steam g e n e r a t o r materials im the p r e s e n c e of h i g h - p r e s s u r e s t e m . Since the c h a r a c t e r i s t i c s sf c o r r o s i o n o x i d e f i l m s formed in the b o i l e r and s u p e r h e a t e r r e g i o n s may d i f f e r , t w o test devices of m a l l scale C4-cm-diam x 70-cm-long) w i l l be c o n s t r u c t e d and o p e r a t e d w i t h continuous ~ ~ ~ ~ n i t osf r i nt hge tritium permeation. Both c~ol-down and h e a t u p c y c l e s sf t h e b o i l e r w i l l b e used to simulate themal transients expected i n MSBR steam systems. me t e s t b a r r i e r oxides w i l l be s u b j e c t e d t o a v a r i e t y of o p e r a t i n g c o n d i t i o n s .

If it i s shorn t h a t o x i d e f i h s are stable candidate s t e m generator materials and that t h e oxides p ~ o v i d ea s i g n i f i c a n c e r e s i s t a n c e to tritium permeation, determination qf t h e role of stem chemistry on t h e oxlde for-= t i o n EEKI e f f e c t i ~ n e s swill be needed. A a a r g e r - s c a i e ( u ~ - ~ ~ xd i a ~ ~ O - ~ T D - ~ O TpI~~ ~) p e d - l o o pf a c i l i t y ~ ~ u be l dused f o r studies in which t h e s t e m composition would be v a r i e d to p r o v i d e i n f o r m a t i o n on: t h e t o l e r a n c e of the oxide t o changes i n ehmical environment expected i n a s u p e r c r i t i c a l s t e m system.

....

C.&

5-57

5.4.6

5.6.6.1

<:.!<.....

Task 4 . 3 . 2

S o l u b i l i t y of t r i t i u m - c o n t a i n i n g s p e c i e s i n molten s a l t s

Subtask 4.4.2.1

S o l u b i l i t y of tritium i n f u e l salt

This s u b t a s k i s r e l a t e d c l o s e l y t o Task 4 . 3 . 6 , s i n c e b o t h s o l u b i l i t y and d i f f u s i v i t y are involved in t r a n s p o r t o f t r i t i ~ mt o s p a r g e gas bubbles "he purpose of t h P s subQP g r a p h i t e and h e a t exchanger tube s u r f a c e s . t a s k i s t o measure t r i t i u m s o l u b i l i t y i n f u e l s a l t .

This measurement f o r hydrogen has proven t o b e d i f f i c u l t i n t h e p a s t s 4 ' s B 8 $ 8 9

.... m

from the p r i n c i p a l l y because of l e a k a g e and permeation of t h e trrgid~~gen abparatus coupled w i t h t h e very s m a l l q u a n t i t i e s of t r i t i u m used i n t h e measurements. However, i n t h e p r e s e n c e a € an excess of hydrogen, tritium permeates m e t a l s a t a lower rate and also can be d e t e c t e d w i t h g r e a t sensit i v i t y . A mixed-isotope method should t h e r e f o r e b e u s e f u l i n determining t r i t i u m s o l u b i l i t y . The h i g h s e n s i t i v i t y w i t h which tritium can b e d e t e c t e d w i l l a l s o permit s a t u r a t i o n of t h e s a l t t o occur w i t h o u t u s i n g gas b u b b l e s , which can c o m p l i c a t e t h e i n t e r p r e t a t i o n sf t h e d a t a . Using 8 l a r g e area of t h i n - w a l l t u b i n g , t r i t i u m can b e i n t r o d u c e d by permeat i o n i n t o a s a l t a l r e a d y s a t u r a t e d w i t h protium. A second t u b i n g s e c t i o n a l s o having a Parge area would serve t o carry permeated tritium t o a t r i t i u m d e t e c t o r . The d e l a y t i m e between t h e i n t r o d u c t i o n and d e t e c t i o n of t h e t r i t i u m w i l l b e a d i r e c t measure of t h e c a p a c i t y of t h e salt f o r d i s s o l v e d tritium. This method i s analogous t o methods used t o measure hydrogen s o l u b i l i t y i n r e f r a c t o r y metals.

5.6.6.2

Subtask 4 . 3 . 2 . 2

S o l u b i l i t y of t r i t i ~ i n coolant s a l t

The d e t e r m i n a t i o n of tritium s o l u b i l i t y i n c o o l a n t s a l t w i l l be made in

....

the a p p a r a t u s w e d i n Subtask 4.3.2.1. Since chemically b ~ u n di s o t o p e s may b e p r e s e n t i n NaBF4-NaF9 a d d i t i o n a l p l a n n i n g based on r e s u l t s from Task 4 . 3 . 4 w i l l b e r e q u i r e d b e f o r e t h i s work is i n i t i a t e d .

I.!<<*

5.6.6.3

,.:.a

,.&

Subtask 4 . 3 . 2 . 3

S o l u b i l i t y of tritium f l u o r i d e i n fuel s a l t

The p r i n c i p a l problems a s s o c i a t e d w i t h the measurement of t r i t i u m f l u o r i d e s o l u b i l i t y i n fuel s a l t are t h e chemical i n t e r a c t i o n w i t h UF3 arid t h e d i f f i c u l t y i n o b t a i n i n g s a t u r a t i o n c o n d i t i o n s . These p r o b l e m probably m i x t u r e of a p p r o p r i a t e l y chosen compocan b e overcome by u s i n g a s i t i o n t o m a i n t a i n c o n s t a n t o x i d a t i o n c o n d i t i o n s . This m i x t u r e would be r e c i r c u l a t e d through a q u a n t i t y of s a l t and r e p l e n i s h e d a t a l o w rate. The t r a n s i e n t b e h a v i o r on adding t r i t i u m w o u l d b e r e l a t e d t o t h e TF and T2 s o l u b i l i t i e s . By a p p r o p r i a t e c h o i c e of relative and t o t a l p r e s s u r e s , s a l t compositions, c o n t a i n e r material and t h e scale sf the a p p a r a t u s , a wide r a n g e of parameters r e l a t i n g t~ TF s o l u b i l i t i e s would b e s t u d i e d .

5 -58 5.6.7

Task 4 . 3 . 3 E q u i l i b r i a between important s p e c i e s c o n t a i n i n g tritium i n s a l t - g a s systems

The m o t i v a t i o n s f o r s t u d y i n g t h e s e e q u i l i b r i a are t o o b t a i n methods f o r p r e v e n t i n g t r i t i u m , which i s g e n e r a t e d in t h e c o r e , from r e a c h i n g t h e steam system of t h e r e a c t o r . There a r e b a s i c a l l y t h r e e chemical i n t e r a c t i o n s f o r "trapping" t r i t i u m : (a> o x i d a t i o n of molecular or atomic t r i t i u m ; t h e o x i d i z e d t r i t i u m i s t h e n chemically bound i n a s p e c i e s t h a t does n o t permeate h o t metals, (b)

(6)

isotope exchange w i t h hydrogen (mass number 1 ) ; f o r i n s t a n c e ,

m + QH- = QT- Q H ~ ,

sorption o n t o g r a p h i t e o r carbon; i n t h e r e a c t o r c o r e , s o r p t i o n of tritium on g r a p h i t e i s h e l p f u l b u t i n s u f f i c i e n t for p r e v e n t i n g e x c e s s i v e release of t r i t i u m i n t o t h e c o o l a n t cirpcuit.

5.6.7.1

Subtask 4.3.3.1

Fuel s a l t e q u i l i b r i a

I n t h e fuel s a l t , t h e o x i d i z i n g c o n d i t i o n s a r e governed by the U4+/U4+ r a t i o ; t h i s r a t i o w i l l b e f i x e d a t about 160 by t h e need t o p r e v e n t c o r r o s i o n s f chromium, formation of uranium c a r b i d e , and o x i d a t i o n of t h e protactinium (see Section 5.4.10). Since s t r o n g l y oxidizing c ~ a ~ c l i tions, i.e. Z Y ~ + / U ~ r+a t i o s g r e a t e r t h a n IOOO, appear t o be n e c e s s a r y t o c o n v e r t all the e l e m e n t a l t r i t i u m to t r i t i u m f l u o r i d e , i t i s l i k e l y t h a t b o t h T2 and TF w i l l b e p r e s e n t i n t h e f u e l salt. The TF/T2 r a t i o w i l l be determined as a f u n c t i o n of t h e ULI+/U3+ r a t i o . Mixtures of TI? and T2 will b e bubbled through molten f u e l s a l t at constant temperature and t h e r e s u l t i n g U4+/U3+ r a t i o s will be measured s p e c t r o p h o t o m e t r i c a l l y .

5,6.7.2

Subtask 4 . 3 . 3 . 2

Coolant salt e q u i l i b r i a

From p r e v i o u s measurements35 and f r o m on-going s t u d i e s (5.5.6 -1, Subtask 4.2.2.1) oxidation%e q u i l i b r i a of tritium i n f l u s r o b o r a t e c o o l a n t can b e c a l c u l a t e d . However, w e do n o t know t h e s o l u b i l i t y of TF i n t h e c o o l a n t . The solubility v a l u e s determined under 5.6.6.2, Subtask 4 . 3 . 2 . 2 , w i l l b e complemented by s t u d y of t h e e q u i l i b r i u m

l / 2 Da(g) 9 1 / 2 NaNiP3 (6) = 1 / 2 NaF(d) -t l / 2 N i O ( c >+ DF(g).

I n t h i s s t u d y , known amounts o f deuterium d i f f u s i n g i n t o a n i c k e l c a p s u l e c o n t a i n i n g NaNiP3 and NaBP4-NaP (92-8 mole %) w i l l b e measured. The s a m e experiment w i l l t h e n b e a p p l i e d t o o t h e r o x i d a n t s ( e . g . , Na3CrFg) and, perhaps, t o a l t e r n a t e c o o l a n t s .

e.. ."

5-59

5.6.8

Task 4.3.4 I s o t o p i c exchange between t r i t i u m and chemically bound hydrogen

Although p r e v i o u s a t t e m p t s 9 ' t o exchange deuterium f o r protium i n t h e s p e c i e s BFaOH- have n o t proved s u c c e s s f u l , i t i s by no means c e r t a i n t h a t i s o t o p e exchange r e a c t i o n s a r e n o t f e a s i b l e i n f l u o r o b o r a t e c o o l a n t . Capsule experiments s i m i l a r t o t h a t d e s c r i b e d above (Subtask 4.3.3 2) will b e performed t o study t h e g e n e r a l r e a c t i o n l / 2 D2(g) 4- H* = B'

1/2 H2(g>

In t h e s e experiments, p a r t i a l p r e s s u r e s w i l l probably be monitored by SpeCtrOScQpy.

lllilSS

5.6.9

Task 4.3.5

TP c o r r o s i o n b e h a v i o r a t low %F a c t i v i t y

I n t h e MSBR f u e l s a l t , a l a r g e f r a c t i o n of t h e tritium would b e p r e s e n t as TF if t h e U4*/TJ4+ r a t i o w e r e reduced t o 0.081. A s i g n i f i c a n t f r a e t i o n of t h e t r i t i u m could t h e r e f o r e p o s s i b l y b e removed from the f u e l s a l t as TP i f t h e gas s p a r g e rate were high enough a n d / o r t h e r a t e of r e a c t i o n of TF w i t h t h e metal s u r f a c e s were v e r y Pow.91 T h i s s u b t a s k w i l l determine t h e r a t e s O € r e a c t i o n of HF ( o r TF) w i t h H a s t e l l s y N and similar a l l o y s under c o n d i t i o n s of low HF ( o r TF) a c t i v i t y . S i n c e TF can probably b e used i n t h i s work, c o r r o s i o n r a t e s c a n b e determined by measuring t h e r a t e o f release s f T2.

5.6.10 5.6.10.1

Task 4.3.6

Diffusivity studies

Subtask 4.3.6.1

D i f f u s i v i t y of HT and H2 i n f u e l s a l t

A time-lag permeation method w i l l b e employed u s i n g deuterium permeation coupled with an ultra-high vacuum system mass-spectrometer detection

method t o determine b o t h t h e s o l u b i l i t y and t h e d i f f u s i v i t y of deuterium ( i n i t i a l l y used as a s t a n d - i n f o r HT and as a c a l i b r a t i n g g a s ) i n t h e salt. A f t e r a s c e r t a i n i n g t h a t t h e r e i s a d e q u a t e agreement w i t h t h e independently measured v a l u e s o f s o l u b i l i t y of t r i t i u m , Task 4.3.2, t h e equipment w i l l b e modified f o r a d e t e r m i n a t i o n w i t h t r i t i u m .

5.6.10.2

Subtask 4.3.6.2

D i f f u s i v i t y of t r i t i u m i n c o o l a n t s a l t

S u b s t a n t i a l l y t h e same approach and equipment used i n Subtask 4.3.6.1 w i l l b e employed.

,.:.:.x

.::..:..;.;,

5-66

5.6,lQ.3

Subtask 4 . 3 . 6 . 3

D i f f w i v i t y of W and TF i n f u e l s a l t

An electrochemLeal method i s expected t o b e applicable t o t h e determination sf d i f f u s i o n c o n s t a n t s of h y c i r ~ g ei ~ o n s i n f u e l s a l t . With adequate s o l u b i l i t y of hydrogen f l u o r i d e (Subtask 4 . 3 . 2 . 3 ) 9 the sensitivity Of t h e e l e c t r o c h e m i c a l method s h o u l d p e m i t a relative157 s t r a i @ t f ~ ~ = ~ a ~ d determhation as a f u n c t i o n of temperature a d composition.

Following t h e completion of S u b t a s k 4 , 3 , 6 m 3 9 a study ~f c ~ d a n ts a l t s would b e bandertaken u s i n g the same method and equipment.

5.6.11

Task 4.3.7

Kocleling of t r i t i u m b e h ~ i n i molten-salt ~ ~ reactors

The d a t a on tritiurn r e a c t i o n s s a l u b i l i t f e s dif f u s i v i t i e s a d permeation o b t a i n e d i n t h e other tasks of Task Group 4 . 3 are needed t o assess t h e d k t r i b u b i o n sf t r i t i m IL I ~~~lten-sd r e. ta c t ~ r ~ ;This . task is d i r e c t e d toward mathematical ~ a ~ d e l of i ~ g the flow and p r o c e s s i n g of tritium in the reactor. The approach taken i n t h i s t a s k would b e similar t o t h a t of B r i g g s and K ~ r s r n e y e r . ~Additions ~ of p r ~ c e s sv a r i a b l e s a d the b e s t new d a t a as i t is developed tu t h e c a l c ~ l a c i o nwould permit t R e necess a r y d @ t a i l e d eXpEoratiOn O f o p t i o n s f o r cQntro%Sf t H i t i l P a E in moltensalt r e a c t o r s . Work i n this task i n t e r a c t s s t r s n g l y w i t h r e a c t o r d e s i g n and a n a l y s i s ( S e c t i o n 8) a n d reactor technology development (Section lo) e

5.6.12

Task 4 . 3 . 8 Tritim adsorption on carbon i n c o n t a c t w i t h t h e coolant

some of t h e tritium generated by t h e mRE: w a s found w i t h i n t h e g r a p h i t e ~ ~ A ~ a t Although o r . ~ ~a similar situation i n an KSBR w i l l b e h e l p f u l , i t i s n o t l i k e l y to prevent excessive m o u n t s of tritium from d i f f u s i n g into t h e coolant. However, i t is p o s s i b l e t h a t g r a p h i t e ( o r carbon) i n c o n t a c t with the c o o l a n t could adsorb a large f r a c t i o n of t h e t r i t i u m . I n i t i a l s t u d i e s have shown that the capacity of carbon f o r tritium wight b e adequate ( ~ 1 0Ci of T2 p e r kg of carbon), b u t that k i n e t i c s may b e i n a d e q u a t e t o p e d t high remuval efficiency. A c a t a l y t i c e f f e c t 0 % v e r y t h i n nickel c o a t i n g s i n enhancing t h e k i n e t i c s would b e expected by amalsgy with many i n d u s t r i a l c a t a l y t i c p r o c e s s e s . This s u b t a s k would b e directed toward bkre p r e p a r a t i o n and t e s t i n g of n i c k e l c o a t i n g s , and determining t h e feasibility sf t h i s approach f o r r e m v h g tritium from t h e coolant.

.. ... m

5-61

5.7

5 7.1 e

TASK GROUP 4 . 4

FISSION PRODUCT CHEMISTRY

Objective

Emphasis w i l l b e p l a c e d on c l a r i f y i n g t h e b e h a v i o r of t h e noble m e t a l f i s s i o n p r o d u c t s w i t h p a r t i c u l a r a t t e n t i o n focused on i d e n t i f y i n g a c t u a l s p e c i e s (metallic o r Othg.l%6se) Which occur at d e f i n e d redox c o n d i t i o n s . Subsequent s t u d i e s w i l l b e aimed a t c h a r a c t e r i z i n g t h o s e factors which a f f e c t t h e t r a n s p o r t b e h a v i o r of t h e s e s p e c i e s i n MSBR systems. Although previous d a t a have i n d i c a t e d t h a t t h e s e f i s s i o n p r o d u c t s were p r e s e n t as reduced metals i n t h e MSaE, t h e redox chemistry of t h o s e most s u s c e p t i b l e to o x i d a t i o n ( e . g . , and MQ) should b e examined as a f u ~ c t i o nof Y4+/U3+ r a t i o and o x i d e i o n c o n c e n t r a t i o n t o v e r i f y t h e s e former COTIC~Usions. This i n f o r m a t i o n w i l l b e u s e f u l i n p r e d i c t i n g t h e amount and n a t u r e of t h e s e elements e n t e r i n g t h e f u e l p r o c e s s i n g system. ....

(L.%

Other f i s s i o n p r o d u c t s w i l l b e i n v e s t i g a t e d f o r t h e purposes of e v a l u a t i n g a l t e r n a t e xenon-control schemes (such as h y d r o f l u o r i n a t i o n of )'1 and developing s t r u c t u r a l component decontamination procedures. F i n a l l y , i n view of new i n f o r m a t i o n , a re-examination of t h e MSRE d a t a may prove f r u i t f u l i n p r e d i c t i n g e f f e c t s from parameter v a r i a t i o n s d u r i n g MSBR operations.

5.7.2

Schedule

The s c h e d u l e f o r work i n t h i s task group i s shown i n Table 5.7.2.

The o p e r a t i n g fund requirements f o r t h i s task group are given i n Table 5.7.3.1, and t h e c a p i t a l equipment fund requirements are g i v e n i n Table 5.7.3.2. 5.7.4

Facilities

NQ new major f a c i l i t i e s w i l l b e r e q u i r e d f o r t h i s task.

5.7.5

, :&

Task 4 . 4 . 1

Noble metal c h e d s t r y

It i s e s s e n t i a l t h a t t h e understanding S € noble-metal b e h a v i o r b e i n c r e a s e d t o a l e v e l comparable t o t h a t of the o t h e r f i s s i o n p r o d u c t s . A w e a l t h of fundamental chemical p r o p e r t y and thermodynamic d a t a exists f o r f i s s i o n p r o d u c t s o t h e r t h a n t h e n o b l e metals. For example, t h e i r o x i d a t i o n s t a t e s have been c h a r a c t e r i z e d and can b e a c c u r a t e l y p r e d i c t e d based on a v a i l a b l e free energies of formation both in s o l u t i s n and in p u r e compounds. The n o b l e metals C ~ E Re x i s t i n s e v e r a l o x i d a t i o n states

Table 5.7.2.

Schedule

for work in Task Group 4.4 -Fission

product Fiscal.

chemistry

year

1974 --

4.4.1

Noble metal chemistry 4.4.1.1 Redox chemistry as a function ST U4+/U3+ ratLo 4.4.1.2 Reactions with oxide ion 4.4.1.3 Reactions with graphite 4.4.1.4 Noble metal agglomeration and deposition 4.4.1.5 Distribution of noble metals between molten salt and He

4.4.2

Iodine

4.4.3

Decontamination

4.4.4

Analysis of fissleon data from MSRE

4.4.5

Studies Facility

distribution of Hastelloy product

M deposition

fn the Gas-System Technology (GUI?)

---

Table 5.7.3.1.

Operating fund requirements f o r Task Group 4.4 - F i s s i o n product chemistry ( c o s t s i n 1000 d o l l a r s ) F i s c a l year

1975

1976

1977

1978

1979

1980

1981

1982

I983

1984

25 25 25

55 55

30 55 55

25 30

199

140

110

1985

4.4.1 Noble metal chemistry 4.4.1.1 Redox chemistry as a function 4.4.1.2 4.4.1.3 4.4.11.4

4.4.1.5

of U4+/U3* Katio Reactions with oxide i o n Reactions with g r a p h i t e Noble m e t a l agglomeration and deposition D i s t r i b u t i o n of n o b l e metals between molten s a l t and He

S u b t o t a l 4.4.1

4 4.2

Iodine d i s t r i b u t i o n

4.4.3

Decontamination of Hastellay N

4.4.4

Analysis of f i s s i o n product d e p o s i t i o n d a t a from MSRE

4.4.5

S t u d i e s i n t h e gas system technology f a c flit y

T o t a l o p e r a t i n g funds f o r Task Group 4.4

110

165

214

- -

110

165

214

254

250

245

~ 215

Table 5.7.3.2.

Capital

equipment

fund requfreme.nta far Task Group 4.4 - Fission (msts in amxl dollars) Fiscal 1375

4.4.1

Noble metal chemistry 4.4.1.1 Redax czhemistq as a function of U"'/U3+ ratio 4.4.1.2 ReacticPne with oxide don 4.4.1.3 l%eactions with graphite 4.4.1.4 Noble metal ag&om@ratiQn and aepositadan 4.4.1.5 Bfstribution of mble metals between molten salt and He Subtotd.

4.4.1

4.4.2

Iodine

distribution

4.4.3

Decontaduation

of Mastelloy

1376

1977

1978

PO IQ

10 5 15

20 15 5

product

chemistry

198P

1982

1383

5 5

year

1979

1980

10 85

25 25

2 5

stuaies iu th~aecd-sy~t~m Techndogy J?aeab%Pty (GSTF) Tstal capital equipment funds far Task Gmup 4.4

4.4.5

PO -

120

1984

1985

5-45

(cfe R e f . 9 3 f o r a d e s c r i p t i o n of p o s s i b l e v a l e n c e s and compuunds f o r niobium h a l i d e s ) w h i l e o f t e n forming s p e c i e s w i t h unusual chemical bonds (e.g., metal-metal bonded c~mplexes)b u t d e t a i l s concerning t h e i r stab i l i t y are n o t a v a i l a b l e . R e a l i z i n g t h a t t h e f i s s i o n p r o d u c t s are formed i n t h e r e a c t o r as h i g h l y charged s p e c i e s which must r a p i d l y a c q u i r e e l e c t r o n s , i t i s p l a u s i b l e t h a t some of t h e s e o x i d a t i o n states may p l a y key r o l e s i n t h e b e h a v i o r of the noble f i s s i o n p r o d u c t s as t h e y p r o g r e s s toward t h e m e t a l l i c s t a t e . Such r e d u c t i o n p r o c e s s e s may determime the u l t i m a t e p a r t i c l e s i z e and d i s t r i b u t i o n found i n t h e reduced s t a t e and should be examined.

5.7.5.1

.&.W

Subtask 4 . 4 . 1 . 1

Redox chemistry as a funetisn of U"+/U3*

ratio

F i r s t i n t h e s t u d y of t h e n o b l e metal redox chemistry w i l l b e a determin a t i o n of the p o s s i b l e o x i d a t i o n s t a t e s and t h e n a t u r e of the s p e c i e s which these elements form i n molten fluoride s o l u t i o n . S p e c t r ~ s c ~ p i c and e l e c t r o c h e m i c a l t e c h n i q u e s will b e used, b u t will r e q u i r e c o n ~ e ~ t r a t i o n s of f i s s i o n p r o d u c t s several urders of magnitude g r e a t e r than t h o s e a n t i c i p a t e d i n an PaSBR. These s t u d i e s would n e v e r t h e l e s s i d e n t i f y those s t a t e s which might m e r i t f u r t h e r s t u d y . Having i d e n t i f i e d t h e s t a b l e s o l u b l e s p e c i e s of these fission p r o d u c t s , experiments i n v o l v i n g e q u i l i b r a t i o n of t h e s e species under c o n t r o l l e d redox p o t e n t i a l s would b e made to determine t h e i r thermodynamic s t a b i l i t y . Standard procedures i n v o l ~ i n gHF-W, gas m i x t u r e s o r U4*/U3f soluti~ns w i l l be used and w i l l b e accompanied by eleetrochemicaP o r s p e ~ t r o p h o t o metric monitoring of t h e s o l u b l e s p e c i e s . 'Phe noble metals w i l l . b e s t u d i e d i n o r d e r of importance based on t h e i r s u s c e p t i b i l i t y t o o x i d a t i o n , t h e i r f i s s i o n y i e l d and t h e i r n e u t r o n cross s e c t i o n s . Because niobium i s t h e most e a s i l y o x i d i z e d , l i t w i l l receive t h e greatest a t t e n t i o n . Molybdenum and the remaining noble metal f i s s i o n product elements w i l l b e s t u d i e d as t h e work p r o g r e s s e s .

.:.:?A

It is p r e s e n t l y known t h a t niobium can exist i n the 5+ a i d 4s o x i d a t i o n s t a t e s i n f l u s r i d e soiution.94--97 men m4+ i s reduced s t i l l further in s o l u t i o n , lower o x i d a t i o n s t a t e s have been i n d i c a t e d but have not been w e l l ~ h a r a c t e r i z e d . ~The ~ 3+ and 2.54- states are ~ R O W I i n p u r e k a l i d e compounds ,9 and c o u p ~ o s s i b l y occur i n f ~ u s r i ~s o~ ~eu t i o n s me r e s u l t s sf Weaver e t a 1 - 9 ~have n o t , kowever, i n d i c a t e d any v a l e n c e s l e s s than 4+ in molten %iF-BeFz (66-34 mole X I . e

Molybdenkutt i s known t o e x i s t i n t h e 6 + , 5+, 4+ and 3+ states,38 w i t h the 3+ s t a t e b e i n g i d e n t i f i e d i n molten f l u o r i d e Lower v a l e n c e s have n o t been r e p o r t e d i r n f l u o r i d e melts.

..... .m

:..... :.m

...a ,

S o l u t i o n s of and No3* w i l l . b e prepared and reduced by e q u i l i b r a t i o n w i t h t h e i r r e s p e c t i v e metals and e v e n t u a l l y w i t h t h e o t h e r redox mixtures mentioned above. Species of lower valence a d w i t h unusual bonding

5-66

p r o p e r t i e s w i l l be sought t o determine i f they can occur as k i n e t i c a l l y These ~ t e experiments s. are expected to c l a r i f y unreactive i n t e ~ ~ ~ ~ d i ~ many of t h e mechanisms and rates which have been presumed t o o c c u r under operating reactor conditions. 5.7.5.2

Subtask 4.4.1.2

Reactions w i t h oxide i o n

The redox chemistry sf n o b l e m e t a l s in MSBR f u e l s may be complicated by r e a c t i o n s i n v o l v i n g trace c o n c e n t r a t i o n s of o x i d e . Oxide may cause formation of oxyions and p r e c i p i t a t i o n of s p a r i n g l y s o l u b l e oxides i n which t h e valence of t h e m e t a l l i c element i s h i g h e r than would be s t a b l e a t the same U3+/U4+ r a t i o i n the absence of o x i d e . Hence, t h e amount of n o b l e m e t a l t h a t can e n t e r s o l u t i o n as an i o n i c s p e c i e s o r b e conv e r t e d to a solid oxide depends on t h e o x i d e c o n c e n t r a t i o n as w e l l as t h e redox p o t e n t i a l . A recent s t u d y l o o has revealed t h a t f i b ' forms the very s t a b l e oxyion h%Oz+ i n molten f l u o r i d e s r e n d e r i n g t h e p e n t a v a l e n t s t a t e more s t a b l e i n s o l u t i o n and t h e oxide Nb205 more s o l u b l e t h a n would o t h e r w i s e be t h e case. The o b j e c t of this s u b t a s k i s t o ~ ~ n d usimilar ~ t s t u d i e s of the chemistry of molybdenum and ruthenium i n molten f l u o r i d e s i n Q P ~ ~t oK d e f i n e t h e b e h a v i o r of t h e s e noble-metal f i s s i o n p r o d u c t s i n an MSBR fuel.

I n t h e absence of o x i d e , molybdenum a p p a r e n t l y L o 1 can b e o x i d i z e d from t h e metal t o t h e t r i v a l e n t s t a t e i n molten f l u o r i d e s a t a redox potential i n t e r m e d i a t e between t h a t r e q u i r e d t o o x i d i z e F ~ tQo ~ e 2 +and N i Q t o Ni2+- I n the p r e s e n c e of o x i d e , o x i d a t i o n should l e a d to t h e formation of very i n s o l u b l e No02 ; however, from a v a i l a b l e formation f r e e e n e r g i e s

the reaction

ShQubd W O t pPoC@edl U T l s i I the u3+/u'+

r a t i o f d b S to

P e t , %he

~ o 4 +i o n is smaller than ~ r 4 +i o n (0.69 vs 0.99 A) whish has a s l i g h t tendency to form an oxyion. Formation of an oxyion of Mo4+ s u f f i c i e n t l y

s t a b l e t o p e r s i s t a t t h e low oxide c o n c e n t r a t i o n of an MSBR f u e l i s a d i s t i n c t p o s s i b i l i t y t h a t should b e i n v e s t i g a t e d . A s i m i l a r s t u d y would b e undertaken f o r ruthenium which i s expected t o be more noble than molybdenum. The f l u o r i d e formed on o x i d a t i o n of t h e metal is expected t o b e RrnF3, w h i l e t h e s t a b l e o x i d e i s probably W U C I ~ ~ though i t s formation by a r e a c t i o n ZmalogOUS t o t h e one above f o r molybd e n m should occur a t mush lower uqu!+-+ r a t i o s (%.sa-9) The i o n s i z e sf ~ u 4 +i s somewhat smaller t h a n ~ 0 4 + ; hence, o x y i s n s in s o l u t i o n are again a p o s s i b i l i t y . m

&.,

5-67

5.7.5.3

Subtask 4.4.1.3

Reaetisns with graphite

Molybdenum can form M 0 2 C and MoC a t MSBR o p e r a t i n g temperatures. The f r e e e n e r g i e s sf formation of t h e s e compounds become n e g a t i v e a t 45Q'C and t h e compounds become more s t a b l e a t i n c r e a s i n g temperatures. lo' Niobium l i k e w i s e forms two c a r b i d e s N b 2 C and NbC103 w i t h n e g a t i v e f r e e e n e r g i e s of f o r m a t i o n (<-20 kcal/mole) and would be s t a b l e a t MSBR opera t i n g temperatures. Nothing appears t o be known concerning t h e c a r b i d e s of technetium, b u t i t seems c e r t a i n t h a t no c a r b i d e formation i s expected from t h e platinum metals Ag, T e , Cd, Sb, and Sn. Experiments w i l l b e conducted w i t h d i l u t e s o l u t i o n s of p o t e n t i a l carbons e e k i n g f i s s i o n p r o d u c t s i n g r a p h i t e c o n t a i n e r s under v a r i o u s redox c o n d i t i o n s . It w i l l b e determined whether c a r b i d e formation does occur and what f a c t o r s govern i t a t t y p i c a l MSBW o p e r a t i n g c o n d i t i o n s . I d e n t i f i c a t i o n of t h e c a r b i d e phases w i l l be made by x-ray a n a l y s i s and t h e s o l u b l e ( p a r t i a l l y o x i d i z e d ) s p e c i e s g i v i n g rise t o t h e c a r b i d e s w i l l be followed by e l e c t r o c h e m i c a l and/or s p e c t r o p h o t o m e t r i c means.

5.7.5.4

Subtask 4.4.1.4

Noble-metal agglomeration and d e p o s i t i o n

The noble metals, molybdenum, ruthenium, e t c . , are formed a t o m i c a l l y i n t h e f u e l of a m o l t e n - s a l t r e a c t o r . Consequently, t h e i r f a t e i n t h e r e a c t o r depends on t h e k i n e t i c s of t h e i r agglomeration and d e p o s i t i o n . These phenomena are i n t u r n expected t o b e dependent on t h e flow r a t e s of t h e l i q u i d , t h e chemical environment of t h e atoms, t h e i r d i f f u s i v i t i e s , and n a t u r e of t h e s u r f a c e s a v a i l a b l e f o r d e p o s i t i o n . The o b j e c t i v e of t h i s s u b t a s k i s t o d e f i n e t h e s i g n i f i c a n t parameters which would permit estimates t o b e made of t h e f a t e s of t h e noble-metal elements. The e x p e r i m e n t a l approach t o b e f o l l o w e d initially w i l l use nsnradicsa c t i v e materials and would make u s e of t h e high s e n s i t i v i t y atoms) of Auger a n a l y s i s . Exploding w i r e methods and chemical decompositions would b e attempted to p r e p a r e f i n e d i s p e r s i o n s i n flowing molten s a l t . "he d e p o s i t i o n of t h e s e materials o n t o g r a p h i t e and metals would be c h a r a c t e r i z e d . Subsequent experiments would u s e tracer methods and i n p i l e f i s s i o n experiments t o c o r r e l a t e t h e earlier r e s u l t s and t o develop a b a s i s f o r t h e monitoring methods r e q u i r e d f o r a r e a c t o r . During t h e d e p o s i t i o n s t u d i e s , a t t e m p t s t o s t u d y agglomeration rates would be made under c o n d i t i o n s of very low flow rates.

5.7.5.5

...,. .=a

Subtask 4.4.1.5 s a l t and H e

D i s t r i b u t i o n of n o b l e metals between molten

The u s e of t e c h n i q u e s developed under Subtask 4.4.1.4 would b e extended t o c o n d i t i o n s of h i g h flow i n t h e p r e s e n c e of a d i s p e r s i o n of helium. Both t h e agglomeration rate and t h e depositi01.l p r o c e s s are expected t o vary from t h e p a t t e r n s observed i n t h e absence of helium. The helium

..&. i..

5-68

wsuld be removed from t h e s a l t i n t o a flowing gas stream of a d d i t i o n a l helium which would be conducted i n t o a d e p o s i t i o n r e g i o n i n whPch t h e gas w i t h e w t s a h e d n o b l e metals would move w i t h v a r i a b l e v e l o c i t y across t e s t specimens o r through f i l t e r s . Auger a n a l y s i s would b e used t o c h a r a c t e r i z e the d e p o s i t s . The size of the helium bubbles would b e a ~ t % - ~v na rgi a b l e i n this s t u d y and would be t h e p r i n c i p a l independemt v a r i a b l e i n the work of t h i s subt a s k . I f a d e q u a t e c o r r e l a t i o n is developed under Subtask 4.4.1.4 between sub-of-pile and i n - p i l e d e p o s i t i o n i n t h e absence of helium, in-pile s t u d i e s under t h e present subtask would n o t b e r e q u i r e d .

5.7.6

Task 4.4.2

Iodine d i s t r i b u t i o n

The behavior of i o d i n e and i t s remOQal froan IlloltEin m i X t U r @ S of LiP-BePz has been s t u d i e d because s f i t a relevance t o t h e problem of "%e removal from MSBRs and t o the containment n e c e s s a r y d u r i n g maintenance o p e ~ a t i o n s . It has been considered that, under t h e normal o p e ~ a t i n gcomditions of a = O.Oa>, i o d i n e i s p r e s e n t i n solution molten-salt r e a c t o r ( Fa

/xup4

i n its most reduced state, % . e .9 as I-. Thus, its removal from molten f l u o r i d e s o l u t i o n has been s t u d i e d by meam of t r a n s p i r a t i o n experiments u s i n g KP-H2 m i x t u r e s as t h e s p a r g i n g g a s . Although t h e r e a c t i o n s t u d i e d

I- c mcg) = H P ( g )

4- F-

i s m e t a t h e t i c a l , hydrogen was present t o parevent c o r r o s i o n sf t h e m e t a l l i c c o n t a i n e r and to s u p p r e s s d i s s o c i a t i o n of t h e HI. The d a t a o b t a i n e d i n d i c a t e d t h a t q u a n t i t a t i v e rmoval s f H I , and t h u s of a s i g n i f t c a n t f r a c t i o n of X e , c a n b e accomplished amd t h a t t h e r a t e - c o n t r o l l i n g step o f t h e r e a c t i o n i s t h e t r a n s p o r t of L- f r o m t h e bulk sf the melt t o t h e surface.769104 since the c o n c e n t r a t i o n s f 1351 i n an MSBR has been e a t b a t e d t o be about 20,000 times lower t h a n i n t h e l a b o r a t o r y experiments and since MS f u e l is 2 IIlOKE? Complex redox S y 5 t a than t h e s o l v e n t s t u d i e d , a d d i t i o n a l . r e s e a r c h is r e q u i r e d i n o r d e r t o tesC many of t h e assumptions and c a l c u l a t i o n s made and to f u r t h e r e v a l u a t e t h i s o l 135xe p ~ i s o n i n g method f o r renovimg i o d i n e from t h e r e a c t o r . ~ ~ n t r of in an KSBR via i o d i n e removal would r e q u i r e t h e s h u l t a n e o u s removal of ' 3 5 ~ sei n c e t h e d i r e c t f i s s i o n y i e l d ~f 145xe i s 1 8 % ~ 5.7.7

Task 4.4.3

Decontamination of Hastelloy %s

The maintenance of some p a r t s of an FEBR may n e c e s s i t a t e the deeoneaminati~nof moderately contaminated e ~ p i p m e ~ t .It i s a n t i c i p a t e d t h a t s u r f a c e decontamination of Nastelloy N w i l l n o t b e a p p r e c i a b l y d i f f e r e n t than s t h e r metals f o r which there i s a long h i s t o r y of e x p e r i e n c e . Experiments t o h v e s t i g a t e decantamination w i l l be c a r r i e d stat t o d e f i n e p r a c t i c a l o p e r a t i n g procedures.

5-69

5.7.8

..m

....a

Task 4 . 4 . 4

Analysis of f i s s i o n p r o d u c t d e p o s i t i o n d a t a from ESRE

The e x p e r i e n c e d t h t h e MSRE showed t h a t t h e noble g a s e s and s t a b l e f l u o r i d e s behaved as s p e e t e d based on t h e i r chemistry. The noble m e t a l b e h a v i o r amd fates,lQ5 however, are s t i l l i n p a r t a matter of c o n j e c t u r e . Except for niobium under u n u s u a l o x i d i z i n g c o n d i t i o n s , i t seems clear t h a t t h e s e elements are p r e s e n t as metals and t h a t t h e i r u b i q u i t o u s prope r t i e s stem from t h e f a c t that t h e metals are n o t wetted by, and have extremely low s o l u b i l i t i e s i n , MSR f u e l s . U n f o r t u n a t e l y , the MSRE s b s e r v a t i o n s probably w e r e s u b s t a n t i a l l y a f f e c t e d by t h e s p r a y system, o i l e r a e k i n g p r o d u c t s , and f l o w t o and from t h e overflow, a l l of which were c o n t i n u o u s l y changing, u n c o n t r o l l e d v a r i a b l e s . The low material b a l a n c e on I3'I i n d i c a t e s a p p r e c i a b l e undetermined l o s s from t h e MSRE, probably as a .noble m e t a l p r e c u r s o r (Te, S b ) . Table 5 . 3 . 3 . 4 shows t h e e s t i m a t e d d i s t r i b u t i o n of t h e v a r i o u s f i s s i o n p r o d u c t s i n a m o l t e n - s a l t r e a c t o r based on t h e MSRE s t u d i e s . U n f o r t u n a t e l y , t h e w2de v a r i a n c e and poor material b a l a n c e s f o r t h e n o b l e metal d a t a make it. u n r e a l i s t i c t o s p e c i f y t h e i r f a t e s more t h a n q u a l i t a t i v e l y . A s a sonsequenee, f u t u r e r e a c t o r d e s i g n s must a l l o w f o r e n c o u n t e r i n g apprec i a b l e f r a c t i o n s of t h e n o b l e metals i n a number of r e g i o n s of t h e chemical u s pro~essing reactor. As indicated i n the t a b l e , c o n t i ~ ~ ~ and the p r o c e s s e s f i n a l l y chosen w i l l s u b s t a n t i a l l y a f f e c t t h e f a t e s of many of t h e f i s s i o n p r o d u c t s .

5 7.9

Task 4.4.5

S t u d i e s i R t h e Gas-System Technology F a c i l i t y (GSTF)

Noble m e t a l b e h a v i o r i n t h e NSRE w a s m o s t d i f f i c u l t to d e t e m i m e and, t h e r e f o r e , w i l l b e d i f f i c u l t t o p r e d i c t i n an MSBB. The noble m e t a l s are born as atomic f i s s i o n p r o d u c t s and are i n s o l u b l e i n t h e fuel s a l t . The atomie-size p a r t i c l e s are not w e t by t h e f u e l s a l t and tend to agglomerate, presumably as a d u s t o r scum on t h e s a l t s u r f a c e and as a d e p o s i t on the Hastelloy N surfaces. It m a y be p o s s t b l e to design experiments u t i l i z i n g the Gas-System Tecknolsgy F a c i l i t y (GSTF)106 to T n v a s t i g a t e m e t a l m i s t d i s t r i b u t i o n between t h e salt and gas stream as a f u n c t i o n of time, s a l t f l o w r a t e , temperature, and strippex- gas void v o l m e . me m e t a l m i s t could p o s s i b l y be g e n e r a t e d by a p l s d i n g w i r e t e c h n i q u e s t o s i m u l a t e f o r m a t i o n of t h e atomic-size f i s s i o n products.

5-70

5.8

TASK GROUP 4.5

5.8.1

Objective

~~~~~~

STUDIES OF MOLTEN SALTS

Any chemical r e a c t i o n t h a t is thermodynamically favored can b e expected t o occur i n a n MSBR f u e l environment. K i n e t i c b a r r i e r s seldom p r e v e n t such favored r e a c t i o n s from proceeding. A s a consequence, thermodynamic v i d e a n extremely used a t a f o r MSBR-related molten f l u o r i d e ~ n i x t ~ pr reo ~ f u l means f o r p r e d i c t i n g the e x t e n t of chemical r e a c t i o n s in such systems and the accumulation of t h e m o c h e m i c a l d a t a for a c t i n i d e , f i s s i o n p r o d u c t , and s t r u c t u r a l m e t a l f l u o r i d e s from t h e measurement of s e l e c t e d chemical e q u i l i b r i a h a s been a n important p a r t of the b a s i c chemical development e f f o r t which h a s s u p p o r t e d t h e MSBR program a t 0 ~ ~ ~ . 4 9 - 5 1TIP^ o b j e c t i v e of t h i s task group i s t o accumulate formation f r e e e n e r g i e s and a c t i v i t y cseff i c i e n t values f o r a l l important substances present i n t h e f u e l w i t h s u f f i c i e n t accuracy t o d e f i n e t h e c o u r s e s f a l l r e l e v a n t chemical r e a c t i o n s over t h e r a n g e s of temperature and salt composition t h a t can QCCUP i n an MSBR. Because of t h e t r a n s c e n d e n t n a t u r e of thermodynamics, i t i s possible t o a c h i e v e t h i s a m b i t i o u s goal through continued j u d i c i o u s c h o i c e s of chemical e q u i l i b r i a f o r measurement. P a r t s p e r m i l l i o n c o n c e n t r a t i o n s of v a r i o u s chemical s p e c i e s ( e . g . , oxygen, t e l l u r i u m , bismuth) can profoundly affect molten s a l t r e a c t o r systems. Porous e l e c t r o d e s have provided a n e x c e l l e n t means of monitoring and e l i m i n a t i n g s i m i l a r low-level i m p u r i t i e s i n aqueous systems and work will b e d i r e c t e d a t developing t e c h n i q u e s and equipment f o r u s e i n molten s a l t s .

5.8.2

Schedule

The s c h e d u l e f o r work i n t h i s task group is shown i n Table 5.8.2,

5 8 3

Funding

The o p e r a t i n g fund r e q u i r e m e n t s f o r t h i s task group are summarized i n Table 5.8.3.1, and t h e c a p i t a l equipment fund requirements are summarized i n T a b l e 5.8.3.2.

5.8.4

Facilities

No s p e c i a l f a c i l i t i e s w i l l b e r e q u i r e d . s p a c e i s adequate f o r t h i s r e s e a r c h .

Existing chemical l a b o r a t s r y

5-71 :w

T a b l e 5.8.2.

Schedule f r work i n Task G r - up 4.5 - Fundamental s t u d i e s s f molten s a l t s

... ,<x*

j 1975 Ij 1976

... ,:H

I I

4.5.1

F r e e energy s f f o r m a t i o n d et e m i n a t i o ns

4.5 2

PO~QUS electrode

... .... .:.=

studies

SX,

1977

1978

1979

1 /-----?-

L---

;

1980

++ I j

.......,

.... e&

Table 5.8.3.1.

O p e r a t i n g fund r e q u i r e m e n t s f o r Task Group 4 . 5 Fundamental s t u d i e s of m o l t e n s a l t s ( c o s t s i n 1600 d o l l a r s ) Fiscal year

4.5.1 4.5.2

F r e e energy of f o r m a t i o n d e t ermina t i o n s POPOUSe l e c t r o d e s t u d i e s

T o t a l o p e r a t i n g funds f o r Task Group 4.5

... ..... .:a

Table 5.8.3.2.

... ....

1975

1996

1979

145

1978

1979

200

140

200

140

165

148

200

256

1980

C a p t i a l equipment fund r e q u i r e m e n t s for Task Group 4 . 5 Fundamental s t u d i e s o f m o l t e n salts (costs i n 1800 d o l l a r s )

,:$=

Fiscal. y e a r ... .... 3,a

4.5.1 .... , :... m

4.5.2

F r e e energy of f o r m a t i o n determinations B Q ~ Q U Se l e c t r o d e s t u d i e s

1975

1976

1979

6 _s

T o t a l c a p i t a l equipment f u n d s f o r Task Group 4.5

1978

1979

E980

5-72

5.8.5

Task 4.5.1 Formation-free energy and activity coefficient determ5nations

Measurements will f i r s t be made of the following equilibrium in L i F BeF2 - ThPq melts as a f ~ n c t i o r tof melt c m p o s i t i o ~and temperature:

The variation of the eorrespsnding equilibrium quotient

composition should r e f l e c t changes in t h e activity coefficients as shorn9

YThP49

ILL

f me fornation-free energies of the oxidess AGNio

where K 2 , the solubility i n LP,BeF4,

f and AGThO2) are quite

5-73 i.:.s

EiF-BeF2-ThPq s a l t m i x t u r e , t h e a c t i v i t y coefficient of ThP4 i n t h i s fuel s a l t w i ~ t u ~can e t h e n be o b t a i n e d . I n subsequent s t u d i e s , o t h e r e q u i l i b r i a of t h e f o l l o w i n g g e n e r a l type w i l l be measured

Here the v a l e n c e of t h e m e t a l M in t h e f l u o r i d e (x) can be Less than or equal t o t h a t i n t h e metal. o x i d e (y). The Mp, ;+fOy/2 combinations t h a t w i l l be considered f o r study i n c l u d e : UF4-UQ2; ZrP4-ZrO-7; TiP3-TiO2; PeF2-Fe2Q3; CrPZ - C r z Q 3 . Prom t h e c ~ r r e s p ~ n d i negq u i l i b r i u m q u o t i e n t s

mX and t h e a c t i v i t y c o e f f i c i e n t yb%Fx of t h e

t h e f o r m a t i o n f r e e energy AG

metal f l ~ o ~ i dmay e be d e r i v e d . A s data on a c t i v i t y c o e f f i c i e n t s e f f e c t s a r e accumulated, i t is planned to ikngr~vethe c o r r e l a t i o n of t h e s e w i t h melt composition, c a t i o n s i z e , and c a t i o n charge. The g o a l i s t o computerize this i n f ~ p m a t i o n , along with an updated t a b u l a t i o n of formation f ~ e ee n e r g i e s , i n a form conv e n i e n t f a r t h o s e who wish t o estimate t h e v a r i o u s chemical e q u i l i b r i a i n W B R fuels.

MonitOPing and/or r m O V a 1 O f l S W COnCEIntrFition Specie% such as 0, Te, and B i i n molten salt f u e l s i s e s s e n t i a l t o t h e s a t i s f a c t o r y and safe o p e r a t i o n of m o l t e n - s a l t b ~ e e d er e~a c t o r s . I n i t i a l i n v e s t i g a t i o n of t h e p o s s i b l e u s e 0%: p o r ~ we l e c t r o d e s fn m~lten-salt fuels are airected at i d e n t i f i c a t i o n of materials and d e s i g n of a s u i t a b l e cell and auxiliary equipment f o r conducting i n v e s t i g a t i o n s i n f l u o r i d e melts '&is equipment w i l l be used t o i n v e s t i g a t e t h e problem of momitsring and/or removal of bismuth ~ K O U I the r e t u r n stream from the chemical p r o c e s s i n g pera at ion^. 10 7 ~ a t ato be o b t a i n e d i n c l u d e t o t a l c u r r e n t requirement Faradaic e f f i c i e n c y , and pOtefa$iaH drop through t h e H>O%SUS OK packed-bed eleCtr0dle BB fUIlcti0n Of e l e c t K O d i e p o t e n t i a l , Salt flOW rate, t-perature, and the c o n c e n t r a t i o n and i d e n t i t y of the bismuth s p e c i e s . This informat i o n will a l l o w t h e e s t a b l i s h m e n t of t h e f e a s i b i l i t y of using a porous electrode as a bismuth monitor 8% as a d e v i c e for e f f i c i e n t removal of bismuth f r m a flowing MSBW s a l t S ~ K ~ E U I I .

5-94

REFERENCES FOR SECTION 5

1. W. R. Grimes, E . G . BohEman, A . S. Meyer and J. M. Dale, The Development Status of 140 lten-Salt Baaeeder Heactors, QRNL-4812 (August H972), p p . 95-167. 2.

4. 5.

Roy C. R o b e r t s o n , Conceptical Design S t t d g of a Sirile-Fluid MoltenS a l t Breeder R e a t o r , 0 R m - 4 5 4 1 (June 1 9 7 1 ) .

B. N . Baubenreich, ,"he Development Status of Molten-Salt Breedm (August 1972), pp. 33-49.

Reactors, ORNL-48l2 6.

W. E . Thoma, Chemical A s p e c k s of NSRE OpePation, ORNL-4658 (December 1951).

K. A . R ~ & ~ e r g e ~ , Brabanstein and 8. E. Thoma, J . Phys. C k m . 76: .Je

1154 (1972).

R. E. Thoma et al., J . P h y s . Chem. 6 4 : 865 ( 1 9 6 0 ) .

PI. C. P . Baes, J r . , J. H. Shaffer and B. F. M c h f f i e , Trans. Am. iirU@Z.

Soc. 6: 393 ( 1 9 6 3 )

K. A . Romberger, C . F. Baes, Js. and H. I%. Stone, J . dnorg. Nucl. Chem. 2 9 : 1619 (1965) e

C . E. Barnberger and 6 . F. Baes, Jr., J . fluel. Mat,. 3 5 : 1 7 7 ( 1 9 7 8 ) .

14.

D. D. s o d , ~ q p h e e r i n gS t u d i e s on Reductive Extraction m d OX&.& Precipitation Techniques fop P ~ ~ ~ e s s iialo n Ztsn g S a l t Reactor Fuels ORNL-CF-72-5-32

(May 1 9 9 2 ) =

I%. C. E. Bamberger, 8 . G . ROSS and C. F. Baes, Jr., J . 4'zorg. ?Jucl. Chem. 3 3 : 767 ( 1 9 7 1 ) . 16.

E. Bamberger, R. G . Ross and C. P. Baes, Jr., Iv'aeionaZ Buyleav, of Standards special PubZieation 364. Solid S t a t e Chemistq, ,Proceedings of 5th MateY.ials Research Spposiwn, p . 331 (1972). C.

5-75

e . F. Baes, J r . , iwSR Ppogram Serrkmznu. Progr. R e p t . f o r Period Ending Feb. 29, 1972, ORME-4782 ( O c t . 1 9 7 2 ) , p . 9 4 .

18.

W. 8. G r i m e s , NueZ. A p p l i c . Technol. 8: 137 (1970).

19.

e. ROSS, C. E. Balaberger and C. F. Baes, JP., J . I r i i r g - Aru@z.

Chem. 3 5 : 4 3 3 (197%). 28.

6. K. T a l l e n t and L. M. F e r r i s , J . Inorya. Nuel. Chem. 3 6 : 1 2 7 7 ( 1 9 7 4 )

H. E. McCoy, The BeveZopment Status of Molten-Salt Breeder QRNL-4812 (August 1972) pp. 195-220.

22.

Reactors,

e . E. Bamberger, J. P. Young and 8 . e. Ross, J . Inorg. ~Vucl.Clzem. 3 6 : 1158 (1974).

23.

R . E . Thoma, CherksaZ F e a s i b i l i t y o f Fueling flslten Salt Reactors with PLtP,, ORE-TM-2256 (October 1968).

24.

C. E. Bamberger, R. 6. Ross, C . F. Baes, Jr. and J. I?. J . ~ n o r g .l & ~ c lChem. . 3 3 : 3591 (1971).

M ~ Z t e nS a l t Breeder Reactor Concept, Qua~i%rZyRept f o r Period Ending J u l g 31, 1974, NP-E9145 (Atomic Energy Commission, Bombay, India).

Young,

26.

C . E. Bamberger, C . F . Baes, Jr. 3. P . Young and C . S . S h e r e r , NSB Program Semiannu. Bogp?. B e p t . Febe 20, 1 9 6 8 , QRNL-4254, pp. 171-73.

27 *

H. F. McBuffie et al., Assessment of Molten SaZts as Intermediate CooZants f o r LPfFBRVs, QRNE-TM-2696 ( S e p t . 3 , 1 9 6 3 ) , p . 20.

2%.

Cantor (ea. ) , PhgsicaZ P ~ o g e r t i e sof l i h Zten-Salt Reactor ,%el, Csolaizt and Flush S a l t s , QRm-TM-2316 (August 1968).

29.

S . Cantor, Density and V i s c o s i t y of Several Molten Fluoride Mktures , 68NL-m-4388 (March 1 973)

30.

L. M. T s t h and L. Q. G i l p a t r i c k , f i e .&quiZibriwn o f B i Z u t e UFQ Solutions Contuined i n Graphite, Q R N L - ~ - 4 0 5 6 (December E9 72)

ti&.... ...

31.- R. B. B r i g g a , J. R. Engel, and B . N. Haubenreich, The Development Status sf MoZ-ken-SaZt Breeder Reactors, O W - 4 8 1 2 (August 1972), pp. 3 8 9 - 4 1 6 . 32.

J. W. Csoke, M§R PPogram Semiannil. Progr. R e p t . Aug. 32, 2969, O m - 4 4 4 9 , p . 92.

33.

J. B. Bates, J. I). Young, M. M. Murray, H. W. K o h ~and 6 . E. Boyd, J . Insrg. NusZ. C"nem. 3 4 : 2 7 2 1 (1972).

34.

C . J . Barton, J . d n o ~ g .NucZ. Chem. 3 3 : 1946 (1971).

....a .

....... .%

.... <%. A

5-76

36.

s. Cantor, J. NucZ. Ida:$er. 4 7 : 177 ( 1 9 7 3 ) .

37.

R . B . B r i g g s , Rsctctor Technc'i. 1 4 : 335 ( 1 9 7 1 ) .

38.

Code sf F e d e r a l Regulations, T i t l e 10, Part 58, Appendix I.

39.

e . L . weaver, E . D . Howard and H. T. P e t e r s o n , Jr., P u b l i c Health Rept. (U.S 8 4 ( 4 ) : 363-371 ( A p r i l l 9 6 9 >

4 % . A. P. Malinauskas and B. M. Richardson, "me S o l u b i l i t i e s of Hydrogen, Deuterium and Belliurm in Molten L i 2 B e F 4 , " d ~ d .Ekg. Chem. Fum2. 13: 242 ( 1 9 7 4 ) .

Grimes, N. V . Smith and G . ?l Wilson, . 2. P @ S e C'hem. 62: 862 (1958).

44.

19. R.

44.

G . M. Watson et al., 9. Chem. Exg. Daka 7 : 285 (3.962).

49.

e . F. Baes, Jr.,

52.

L. PI. F e r r i s , J. C . Mailen and F. J. Smith, J . 4iZorog. ~ ' J z I G ~ . Chem. 33: 1325 (1971).

dT.

I\TSncZ. Mater. 51: 149 ( 1 9 7 4 ) .

5-7 7

54.

L. M. F e r r i s , IFZQP~.. Nuel.. Chem. L e t t e r s 7: $91 (1971).

55.

F. A . Posey, EZectroZytic Demonstration Uni-t fop Copper Romoval from B i s t i Z Z a t i o n PZax-b BZewdmn, QRNL-TM-4112 (March 1973) e

57.

D. D . Sood, W e B e Laing and C. E. Bamberger, MSR PpogramMoR&hZy Roport for Period Ending A p r i Z 30, 1 9 9 2 , MSW-72-36 (May 1, %972), p . 16.

58.

H. %a.

B r o n s t e i n and D. k . Manning, J . EZectmchem. Soc. 119: 125

(1972)

59.

R. G . Ross and C. E . Bamberger, p e r s o n a l c o m u n i e a t i o n .

$0.

A . L. Mathews and C. F. Baes, Jr., d n o q . Chern. 7: 373 (1968).

61. @W. . Kee, personal c o m u n i s a t i o n . 62.

63.

J. P. Young, C. E. Bamberger and R. 6 . Ross, J . i m r g . NucZ. Chem. ( i n press). P . T. Cunningham, S. A . Johnson and E , J. Cairns, J . EZectrschem. 120: 328 (1973).

SOC.

64.

L e t t e ~from C. F . Baes and 6. E. Bamberger t o W. 8. Grimes, J u l y 11, 1 9 7 2 .

65.

I>. M. Gruen, 8 . %. MsBeth, M. S. F o s t e r and C. E. CrouthameP, J . Phys. Chem. 70: 4 7 2 (1966).

66,

C. E . Bamberger, "ExperimntaP Techniques in Molten F l u o r i d e Advances i n MoZten SaZt C h e m Z s t q Plenum Press, Vola 3 (in p r e s s ) .

Chemistary,

.... .s *

....

.>a

i....

.... ..'.D . L

67.

W. Suski, Phys. S-bat. S o l i

68.

G. V. E l l e r t and V. M. SPoyranskikh, R m s . J . Inorg. Chern. 17: 303 (1972).

78.

J. H. S h a f f e r , personal communication.

71.

52.

D. M. Richardson and J. H. Shaffer, Ip4sBP Mo~zkhh.~Report f u r Ockaber 2969, MSR-69-106, pp. 18-20.

A 13: 675 ( 1 9 7 2 ) .

m Memo to C. P . Baes, Jr. from C. E. Bamberger and R. G. Ross, February 1, 1972.

5-78

J. W. Cook%, f B R Program Semimnu. Progr. R e p t . f o r Period Ending Aug. 31, 2 9 E 9 , ORNL-4449, ( A u ~ . %l, 1 9 6 9 ) , p . 9 2 . 75

...t

F. Baes, Jr

Wichner, 6 . E. Bamberger and B. F . Preasier, "Removal of I o d i d e from LfP-BeF, Melts by HF-H2 Sparging -Applicat i o n of I o d i n e Desorption from MSBR Fuel," t o be p u b l i s h e d . 6.

%. 61. Toth, J . E'.

R. P

Young a n d G . P. S m i t h , Anal. Chen. 4 1 : 683-5

(1969). 78

R . F. A p p l e and A . S. Meyer, !k%'EP Semiannu. Ppogr. R e p t . o m - 4 5 4 8 , p . 185.

A q . 1970,

81. 82.

H. T a n a k a , A . Yanaguchi and J. M o r i y a m , f l i p p ~ nKinzaki Gakkai-Si

35: E1161 (n9sf). 83 84.

A . S. Dworkin and M. A . B r e d i g , J . Chem. Eng. Da$a 15: 505 (11970).

S h a f f e s , J . P h y s . Cham. 71: 3218 (1967).

88.

B. E. F i e l d and J. HI.

89.

A . P. MaPinauskas, D. PI. Richardson, J. E. Saveplainen and J. H. Shaffer, Znd. E.pg. Chem. Fund. aa: 584 (Ib972).

J. P . Young, 9. B. Bates and G . E. Boyd, M R P ~ ~ g r m S @ r P r i a n n ~ .

P r o g r . aept. Feb. 2 9 3 2 , QRrn-4782, p * 5 9 .

5-79 91.

R . B. B r i g g s , J. R . EngeP and P. N. Haubenreick, The Development OW-4812 , p 4 1 3 .

Status of Mo lten-Salt Breeder Reactors

92.

R . B. B r i g g s and 8. B . Korsmeyer, B i s t K b u t i o n of T r i t i u m i n a Z O O 0 MVie) Y i B R , Om-CF-78-3-3 (March 18, 1970)

93 *

F. F a i r b r o t h e r , m e Chemistq of Niobium and T m t a Z w n , Elsevier, New York, 1967.

94 *

S . Senderoff and 6. W. M e l l o r s , J . Electrochem. SOC. 113: 6 6

(19669. 95.

G. Ting, C . P. Baes, J r . , and 6. Mamantov, MSK @o_aran?Semiannu. P r ~ g r .R e p t . f 5 r Period Ending Peb. 29, 2 9 7 2 , OWL-4982, pp. 87-91.

96.

J . D. Redman and C. P. Weaver, /GI? P r 5 g y . m Semismnu. P r o p . Rep&. for Period E n d i n g Feb. 29, 2972, ORNL-4782, pp. 91-95.

L. M. Toth and L . 0. G i l p a t r i c k , unpublished r e s u l t s .

C . F. Weaver e t al. , SR H r o g m Sskunnu. P r o p . Rept. f o r - Period Ending Peb. 28, 2969, ORNL-4396, p. 657-62.

99.

L. M. Toth, J . R. Young, and G . B. Smith, MSR Pkog~arnSemiannu. Ppogr. Rept. for Period Ending Peb. 29, 2968, ORNL-4254, p . 136.

100. G a m Ting , Thermodynamic and E l e c - b o c h e ~ c a l Stzcdies of Nisbizon i n Molten FZuoridea and ChZoroaZknates, Ph.D. T h e s i s , U n i v e r s i t y of Tennessee, Knoxville (August 1973)

.&;

101.

N. J. Meyer, 6 . F. Baes, J r . , and K. A . Wsmberger, Reactor Crhel??. Annual Rept. for Period Ending Dec. 31, 29E7, QWNL-4229, p. 32.

102 *

J. P. E l l i o t t and M. Gleiser, Thermochelrtistnj for Stee~making, Addison-Wesley, Reading, Mass., 1960.

103.

E . K. Storms, %e Kefras-kny Carb<des, Academic P r e s s , New York, 1967, p. 61.

104.

R. P. WPchner and 6. F. Baes, Jr,, S i d e s t r e a m P r o c e s s i n g f o r Cont i n u o u s I o d i n e and Xenon Removal from MSBR F u e l , ORNL-CP-72-6-12

(1972). 105

A . Houtzeel and F. I?. Dyer, A Study of F i s s i o n P r o d u c t s i n the Molten-Salt Reactor Experiment by Gama Spectrometry, OWE-1M-3151 (August 197 2 1

106.

W. K. Furlong, ConcegtuaZ System Design DeseKption of f i e Molten S a l t Loop for Testing Gas Sgstems, OW-CF-71-1-40 (Jan. 1971).

109.

E * E McNeese, The Development Status o f Mc,lten-Salt Breeder Reactops, QRNL-4812 (August 19721, p a 352.

." .. I .

..-....

...

,?.&

... ....

. : . : . y ,

6.1 INTRODUCTION ... ....

....

~<&

6 1 B a

Objective

Analytical research and development activities will be directed toward providing the chemical devices and methods for the analyses required to achieve a safe and efficient ~ l o l t e n - s a l t breeder reactor. To this end t h e highest priority will be assigned t o demonstration of the feasibility of in-line methods for constituents 0% properties s f reactor streams t h a t are deemed essential %OK power reactor operation. Essential determinations will include the redox c~nditionsf the fuel, t o t a l uranium concentration in the fuel, oxide and bismuth contamination, C O ~ K ~ S ~ Q I I . indiCatQKS in t h e f u e l and C Q O l a b l t , and meaSur€%l@n%s Of t P i t i U F I l diStKibUtion throughout the system. Because of the importance of such determinatioms, a Cii~er~itgr of approaches will be investigated. A similar redundancy may ultimately be employed in operating reactors ts provide "back-up" measurements for essential determinations.

,.m

....

... .&

... ,*a

... .... .... . a

This development activity will generate a d i v e r s i t y 05 in-line analytical techniques many of which will not be employed in an o p e r a t i n g reactor. a CQntinUOUS @VdUathXl W%PP be =de t0 is%en%ify thOS62 i n - l i n e teChniquE?S that would provide the most Qa%uabledata and to develop as many as are technically feasible in order that they can b e incorporated i n t o development system as well a s teat and deglonstratfon reactors. In t h e f i n a l application of analytical devices to power ~ei~etors, the number s f analytical transducers would be reduced to a more modest l e v e l that includes only those essential to safe operation and those which have been d t ~ ~ ~ ~ s tt ~ o acontribute t e d t o an ~ c Q ~ o E I P cj u ~ sPt i~f ~i a b l e increase in plant efficiency.

6-1

6-2

6.1.2

Scope

The scope of t h i s a c t i v i t y i n c l u d e s t h e f o l l o w i n g areas of methodology: I n - l i n e Electrochemical Analyses (Task Group 5.1)

Appkication of Speetrophotometric Methods (Task Group 5.2) Analyses by Chemical Methods (Task Group 5.3)

Analysis of G a s S t r e a m s (Task GKOUP 5 . 4 ) &?tectiQHlof FissirXi Products and

by & m a

. .

SpectrOPnetry (Task

Group 5.5) I n - l i n e A n a l y t i c a l T e s t F a c i l i t y (Task Group 5.6) S p e c i a l S t u d i e s (Task Group 5.7) Each of t h e s e t a s k groups i s expected t o c o n t r i b u t e analysis methods a p p l i c a b l e t o t h e t h r e e f u n c t i o n a l s u b d i v i s i o n s of t h e r e a c t o r : t h e f u e l system, t h e r e p r o c e s s i n g system and t h e c o o l a n t system. The l a s t task group, S p e c i a l S t u d i e s , incorporates a v a r i e t y of activities inc l u d i n g t h e i n v e s t i g a t i o n of advanced approaches t o which only c u r s o r y s t u d y has y e t been given; t h e simultaneous u s e of t w o o r more of t h e f i r s t six t e c h n i q u e s ; t h e e x p l o i t a t i o n of t e ~ h n o l o g i c a lb r e a k t h r o u g h s ; t h e a p p l i c a t i o n , w i t h automation where p r a c t i c a l , of f u l l y developed i n i n s i t u methods i n s u p p o r t of o t h e r Program a c t i v i t i e s ; and t h e l i n e o r -~ e v a l u a t i o n of t h e v a r i o u s methods i n terms of f i n a l r e a c t o r requirements.

6.2 6.2.1

P R Q G W BUDGET AND SCHEDULE

Schedule and key p r o g ~ a mm i l e s t o n e s

The s c h e d u l e f o r work on a n a l y t i c a l r e s e a r c h and development i s shown The key program m i l e s t o n e s f o r t h i s a c t i v i t y are l i s t e d i n Table 6.2.1.1. i n T a b l e 6.2.1.2 and occur a t t h e t i m e s i n d i c a t e d i n Table 6.2.1.1. 6.2.2

Budget

The o p e ~ a t k n gfunds r e q u i r e d by t h i s a c t i v i t y are shorn i n Table 6.2.2.1, and c a p i t a l equipment fund requirements are given i n Table 6.2.2.2. NTS, EXPERIENCE, AND STATUS OF DEVELOPMENT

In order t o exploit f u l l y t h e unique f e a t u r e s of t h e MSR concept and e n s u r e safe and e f f i c i e n t r e a c t o r operatiogl, it w i l l b e n e c e s s a r y t o m a i n t a i n adequate s u r v e i l l a n c e of t h e c ~ ~ i p ~ i t of i o v~a rai o u s r e a c t o r streams. I d e a l l y , aPP such a n a l y s e s would be performed a u t o m a t i c a l l y

.... ! . q s

6-3

with transducers located in the salt streams, since analysis of discrete samples in hot cells is subject to unavoidable delays and is expensive. A t present, it appears that it way not be practical to measure mjor fuel constituents such as Li, Be, Th, and fluoride, by in-line methods ,.s

....

in an MSBR. Fortunately, continuous monitoring of these constituents will not be critical to the operation of a reactor. The more critical determinations, on the other hand, are generally amenable to in-line measurement. Determinations which appear to be of most significance include the redox condition of the fuel,* corrosion product ions (particularly ~ r 2 + > oxide, bismuth, hydrogen and tritium, certain fission products, and protactinium in fluoride streams. The accurate determination of total uranium concentration (with an accuracy of about 1 part in lo4) in the fuel salt would also be quite useful in the calculation of long-term reactivity balances. Determinations for some materials will I S the f u e l processi~gsystem. S k i be required in the chhr’ide S ~ K ~ E U Xof larly, methods will be required to monitor corrosion products in the coolant salt together with free and combined hydrogen and tritium, oxygenated species and any redox buffer couple whieh may be incorporated into the coolant salt. In-line analyses for permanent gas contaminants, moisture, tritium, hydrocarbon, and fission product gases will be needed in the fuel cover gas. To this must be added BF3, HF, hydrogen, and hydrolysis products in the codant cover gas (or analogous constituents if an alternate coolant is selected), and perhaps NF, F2, and UFg in gaseous stream from the processing system.

It should b e noted that in addition to economies of time and expense, the in-line techniques will provide information not attainable by discrete sampling methods. A notable example is the U3+/U4* ratio in the fuel. This r a t i o is prohibitively sensitive to atmospheric contamination during sampling and sample transfer in hot cells, and is rather meaningless on frozen samples because the ratio undergoes changes during cooling as a result of shifts in equilibrium. Another example is the determfnation of trace constituents in gases, which is notoriously difficult if n o t impossible t o effect by withdrawing samples. It is evident that the ultimate need for an MSBR is an analytical system that includes all needed in-line analytical measurements that are feasible, backed up by adequate hot cell and analytical laboratories. In the interim period it is also necessary to develop capabilities and to provide analytical support for the technology development activities in the Program.

* he ~ 3 + / ~ 4 ratio + is a measure of the redox potential of the fuel which [.S&

influences the rate of corrosion and the distribution of certain fission products and tritium in the reactor system.

Table

6.2.1.1.

Schedule I

5.1

In-line

electracherdcal

5 a2

Application of raethods ta mw

5.3

Analyses

by chemical

5.4

Analysis

5.5

Detection of fission praducts Pa by gamma spectrametry

5.6

h-line

Analytical

5.7

specia.l

studies

gas

analyses

spectrophatametric salts methods

stream

Test

PacilPty

and

for

analytical

research

and developtent Fiscal

year

6-5

Table 6.2.1.2.

Key milestones f o r a n a l y t i c a l r e s e a r c h amd development -

Hilestone

D e s cr i p tisn

Complete b a s i c t e l l u r i u m study

Complete basic e v a l u a t i o n of e l e c t r o c h e m i c a l bismuth methods

Complete development of methods f o r c o r r o s i o n products and protonated species f o r NaBF4

Start evaluation sf r a d i a t i o n e f f e c t s OR methods

Complete e s s e n t i a l methods f o r p r o c e s s i n g system

Demonstrate f e a s i b i l i t y of p r e c i s e s p e c t r o p h o t o m e t r i c methods t o +I% l e v e l

E s t a b l i s h ultimate p r e c i s i o n of s p e c t r a l methods f o r t o t a l llraniunn

Develop p r a c t i c a l i n - l i n e t r a n s p i r a t i o n system f o r t e s t i n g

E v a l u a t e gas-chromatographic and mass-spectrometric methods f o r testing

Complete e v a l u a t i o n of y-spectrometry c a p a b i l i t i e s

Complete c o n s t r u c t i o n of A n a l y t i c a l T e s t Facility

Demonstrate i n - l i n e o x i d e m e t h o d f o r f u e l streams

Complete b a s i c s t u d i e s of r a d i o l y t i c oxide removal

Start in-line a p p l i c a t i o n s of a n a l y t i c a l methods

Submit recornmendations f o r complete chemical a n a l y s i s for reactors

Table 6.2.2.1.

electrocbewfcal

~unrmary of operating (costs

budget for analytical in 1000 dollars)

research

and development

Fiscal

year

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

5.1

In-line

analyses

100

123

140

150

157

150

138

5.2

Application of spectraphotometric lnetbods to MSRP salts

5.3

Analyses

by chemical

5.4

Analysis

of gas stream

5.5

Detection of fission products Pa by gamma spectrometry

130

125

460

365

5.6

In-l-he

Analytical

5.7

SpCxial

studies

Total

methods

Test Facility

and 12

21 43 ---e-w-lb80 290

360

410

480

515

553

550

90 --513

1986

Table 6.2.2.2.

Summary of c a p i t a l equipment funds required f o r a n a l y t i c a l chemistry r e s e a r c h and development ( c o s t s i n 1000 d o l l a r s )

F i s c a l year

1975

1976

1977

1978

1979

5.1

I n - l i n e elec trochemica1 analyses

5.2

Application of spectrophotometric methods

5.3

Analysis by chemical methods

5.4

Analysis o f gas e t r e a u s

5.5

Detection of fission products and

1980

1984

100

-9 -38

118

153

156

141

192

208

31983

In-line Analytical T e s t F a c i l i t y

T o t a l c a p i t a l equipment funds

1982

Pa by pianma spectrometry 5.6

1981.

1985

6-8

The mjor development of a n a l y t i c a l methods f o r d i s c r e t e samples w a s a s s o c i a t e d w i t h t h e o p e r a t i o n of the MSRE. The a n a l y t i c a l methods f o r t h i s reactor were developed t o s u p p o r t t h e objectfves of t h e chemical s u r v e i l l a n c e program.1 with t h e e x c e p t i o n of i n - l i n e a n a l y s e s of t h e off-gas and remote gama s p e c t r o ~ ~ t( d~eys c r i b e d l a t e r i n t h i s s e c t i o n ) , a l l a n a l y s e s were p e r f o m e d on b a t c h s a m p l e s e i t h e r i n hot c e l l s o r by bench-top methods. P r i o r to the K3U programb s u b s t a n t i a l e x p e r i e n c e was gained i n t h e h a n d l i n g and a n a l y s i s of n o n r a d i o a c t i v e f l u o r i d e salts i n the ANF Program. I o n i c o r i n s t r u m e n t a l ~ e t h o d shad been developed f o r most rraetallbic cons t i t u e n t s and methods were a v a i l a b l e f o r F- (pyrohydrolysis)' and s u l f u r 3 For MSRE a p p l i c a t i o n , i t was n e c e s s a r y t o adapt t h e s e m e t h ~ d s h s t - c e l l o p e r a t i o n s . a technfque hVolVing t h e evOlutiCln Of eleM@ntal en by r e a c t i o n w i t h BrF3 h a s s i n c e r e s u l t e d i n t h e versatile KBrF4 r n e t h o c ~ (~f o r o x i d e in i n ~ ~ g a n samples ic A n o n - s e l e c t i v e measurement of "reducing power" of a d e q u a t e s e n s i t i v i t y had been developed (hydrogen e v o l u t i o n method) A g e n e r a l expertise@ i n t h e radiochernical s e p a r a t i o n and measurement of fission p r o d u c t s was a v a i l a b l e from earlier r e a c t o r p ~ ~ g r a mat s OREX, and u s e f u l e x p e r i e n c e w i t h h - l i n e gas a n a l y s i s , p a r t i c u l a r l y p r o c e s s chromatograph w a s available fb-0111o t h e r programs e

D u ~ i n gt h e o p e r a t i o n s f t h e MSRE and i n t h e subsequent technology prsgram9 deV@lOpment Of methods f 6 P d i s c r e t e SialIlples Was Continued, and t h e Laboratory a c q u i r e d i n s t r u m e n t a t i o n f o r newer a n a l y t i c a l t e c h n i q u e s . I n s t r u m e n t a l methods which have or are expected t o c o n t r i b u t e t o t h e program i n c l u d e : x-ray a b s o r p t i o n , d i f f r a c t i o n , and fPuoreseence techn i q u e s ; NIB; s p a r k s o u r c e mass s p e c t r o m e t r y ; ESCA and Auger s p e c t r o m e t r y ; e l e c t r o n &croprobe measur@m.ents; scanning electKOn d c r o s c o p y ; R a a n SpeCtrOmetry; FObarier t r a n s f o r m SpeCtPOmetPy; neUtlrOIb a c t i v a t i o n anZilysiS; delayed neutron methods; photon a c t i v a t i o n a n a l y s i s ; and scanning w i t h high-energy p a r t i c l e s , e . p r o t o n s . The d e t a i l e d d e s c r i p t i o n sf a l l a n a l y t i c a l methods a v a i l a b l e t o t h e program i s beyond the scope of t h i s d i s c u s s i o n . T a b u l a t i o n of a n a l y t i c a l c a p a b i l i t i e s a t ORNL and w i t h i n t h e Oak Ridge complex are r e p o r t e d elsewhere. C e r t a i n developments merit a d d i t i o n a l ~m@ntisn and are d i s c u s s e d below.

6.3.2.1 The p r e p a r a t i o n of homogenized samples s f E R E f u e l f o r e l e m e n t a l a n a l y s e s p r e s e n t e d p r o b l e m because of t h e r a d i o a c t i v i t y and t h e hydroscopic nature of t h e salt.9 salt samples were t a k e n i n s m a l l copper l a d l e s which were s e a l e d under helaim i n a t r a n s p o r t c o n t a i n e r i n t h e sampler-enricher 1 for d e l i v e r y t o t h e hot cell. There t h e l a d l e w a s unloaded and s e c t i o n e d . The salt w a s removed from the t r u n c a t e d l a d l e and homogenized by v i g ~ r o u s shaking i n a p u l v e r i z e r v e s s e l . Salt t r a n s f e r w a s t h e n made to a polye t h y l e n e v i a l threaded i n t h e bottom of t h e p u l v e r i z i n g vessel w i t h minimal a t ~ ~ ~ s p h eer ~i cp o s u ~ e T . h i s procedure provided a f r e e - f l b o ~ h g

k..

6-9

powdered sample w i t h i n two hours of r e c e i p t of t h e l a d l e . Atmospheric exposure was s u f f i c i e n t t o compromise t h e d e t e r m i n a t i o n of o x i d e and U3+, b u t d i d n o t a f f e c t o t h e r measurements.

6.3.2.2

Bxide

Because of t h e s e n s i t i v i t y of t h e p u l v e r i z e d salt t o unavoidable a t m ~ s p h e r i c contamination, t r a n s p i r a t i o n t e c h n i q u e s i n which t h e e n t i r e sample c o u l d be analyzed w e r e adopted. For t h e more c r i t i c a l determinat i o n s , t h e m o s t s u c c e s s f u l a p p l i c a t i o n of t r a n s p i r a t i o n t e c h n i q u e s w a s the d e t e r m i n a t i o n of o x i d e by h y d r o f l u o r i n a t i o n . The method i s based on t h e e v o l u t i o n of water which o c c u r s when m e l t s are sparged with m i x t u r e s of anhydrous HF and hydrogen. By removing s u r f a c e m o i s t u r e w i t h a p r e m e l t i n g h y d r o f l u o r i n a t i o n s t e p and by measuring t h e water evolved from 50-g samples as a n i n t e g r a t e d s i g n a l from an e l e c t r o l y t i c m o i s t u r e monitor, o x i d e c o n c e n t r a t i o n s of about 50 ppm were measured w i t h p r e c i s i o n b e t t e r than 210 ppm.

6.3.2.3

Uranium

A I I ~ I ~ S ~%OK S uranium by coulometric t i t r a t i o n 1 2 showed good reprodue-

i b i P i t y and high p r e c i s i o n (0.5%), b u t on-line r e a c t i v i t y balance calc u l a t i o n s w e r e about ]lO-fo%d more s e n s i t i v e t h a n t h i s i n e s t a b l i s h i n g changes i n uranium c o n c e n t r a t i o n s w i t h i n t h e MSRE f u e l s a l t ~ i ~ c ~ i t . R e a c t i v i t y b a l a n c e in a n MSBR may b e less u s e f u l , however, because of u n c e r t a i n t i e s i n t r o d u c e d by continuous p r o c e s s i n g of t h e f u e l s a l t . I t w a s demonstrated t h a t uranium from t h e f l u o r i n a t i o n of 58-g samples of molten f u e l could be q u a n t i t a t i v e l y c o l l e c t e d as decontaminated UFg. The t e c h n i q u e w a s used p r i m a r i l y t o s e p a r a t e uranium f o r p r e c i s e i s o t o p i c a n a l y s i s , b u t s u f f i c i e n t work w a s done t o e s t a b l i s h i t s p o t e n t i a l f o r more a c c u r a t e uranium d e t e r m i n a t i o n by measurement of t h e s e p a r a t e d uranium outside t h e h o t c e l l .

6.3.2.4

u3+

A hydrsgenatiorm-transpirae.iofl method w a s developed f o r t h e d e t e r m i n a t i o n

sf U3* in f u e l s a l t . 1 3 The r a t e of p r o d u c t i o n of HF from t h e s p a r g i n f u e l w i t h hydrogen i s a f u n c t i o n of t h e i n s t a n t a n e o u s r a t i o of U3*/U4 $ O f A computer program w a s developed t o compute y i e l d s of HP from t h e reduce

t i o n of UF4 and c o r r o s i o n product f l u o r i d e s as a f u n c t i o n of composition '+ c o n c e n t r a t i o n s and r e d u c t i o n c o n d i t i o n s and t h u s p e r m i t e s t i m a t i o n of Y from t h e i n t e g r a t e d W y i e l d s from s e q u e n t i a l r e d u c t i o n s t e p s at two t e m p e r a t u r e s . R e s u l t s of such measurements were i n r e a s o n a b l e agreement w i t h "book values8' corn u t e d from r e a c t s ~c h a ~ g i n gand o p e r a t i n g d a t a d u r i n g 235u operation.y4 The method proved i n a d e q u a t e for u s e w i t h the ~ s w e rconcentrations of uranium in t h e a 3 3 ~fuel.

6-10 A volta~~~etric method was tested f o r the measurement of U 3 + / V G ratios i n remelted fuel samplesa5 (see section on E%ectrochmical Research for a description of voltammetry). Measurements were performed with elec-

trodes inserted in samples remelted in their ladles. Hore atmospheric exposure was incurred than in the oxide determination, because it was necessary to cut off the t o p of the ladles t o accommodate the electrodes. Accordingly, ratios below those expected were obtained. However, nonually shaped reduction waves for cr2+ and u Q were ~ recorded, and the reduction sf the fuel by hydrogen sparging was foilswed VQ8tamUetriCally. Changes in ratio w i t h temperature were c ~ ~ ~ s i s t with e n t thermodynamic predictions of equilibrium shifts between the uranium couple and corrosion prodtact ions. This indicated t h a t the radiation level of the samples had negligible effects on the method and supports the potential of voltammetry for application to reactor salt streams. 6.3.2.5

Spectrophotometry of radioactive samples

A facility was constructed16 which permitted measurements with highly radioactive samples within a hot cell by using the components of a spectrophotometer located outside the cell. A system of extended o g c i e s directed the chopped reference and sample beams through the cell wa11s, focused the sample beam at t h e center of an optical furnace and returned the mo beams through the wall to the monoch~o~ator-detector section of the instrument. The system design fnsluded devices for remelting large salt sanples under i n e r t atmusphere and dispensing portions t o spectrophotometric cells, but because of the pending shutdown of the PISRE, a

sample system was devised to fill windowless cells by direct immersion in the fuel. Despite precautions to prevent atmospheric. exposure, the U3+ in the samples was completely oxidized before measurements cou1d be de. n e spectrum of VM was recorded, however, as was that of ~ 3 $ (following a reduction with uramium metal). Comparison of the spectra of these samples with those sf nonradioactive preparations indicated XI adverse effects from the activity of the fuel and demonstrated the f e a s i b i l i t y of the technique. The facility has since been used to measure the spectra of tra~~suranium elements and protactinium in molten salts. 6.3.2.6

Gas analysis

Equipment was installed at the HSRE t o p e r f o m limited in-line analyses of the seaCtOr Off-gases, Using a CheITld CQndUctfVity Cell 88 a transducer. By means of an oxidation and absorption train17 both total impurities and hydrocarbons were measured in the off-gas. The sampling station a l s o included a system for the cryogenic collection of X ~ ~ Q W . and krypton on molecular sieves to provide concentrated samples for the precise d e t e r m i n a t i o n sf the isotopic ratios of krypton and xenon by mass spectrometry. During the last two ~ U R Sof the MSRE, equipment18 was installed at the reactor to convert the tritium in various gas streams to water for measurement by scintillation counting.

'iss;

6-11

6.3.2.7

Gama s p e c t r o m e t r y at t h e

By means of a p r e c i s e c o l l i m a t i o n system mounted on a maintenance s h i e l d , r a d i a t i o n from f i s s i o n products d e p o s i t e d on r e a c t o r components w a s deFrom t e c t e d by a h i g h - r e s o l u t i o n l i t h i u m - d r i f t e d germanium diode. l t h e gmma s p e c t r a o b t a i n e d , s p e c i f i c i s o t o p e s such as n o b l e m e t a l f i s s i o n p r o d u c t s were i d e n t i f i e d and t h e i r d i s t r i b u t i o n w a s mapped by moving t h e c o l l i m a t i n g system.20 During t h e latter r u n s of t h e r e a c t o r such measurements w e r e made d u r i n g power

6.3.2.8

Bismuth

P r o c e s s i n g of t h e f u e l salt by selective e x t r a c t i o n i n t o l i q u i d bismuth ( d e s c r i b e d i n S e c t i o n 3) r e q u i r e d t h e development of more s e n s i t i v e methods f o r the d e t e r m i n a t i o n of bismuth i n f u e l s a l t . An i n v e r s e p o l a r o g r a p h i c t e c h n i q u e w a s developed which has d e t e c t i o n limits of about 50 ppb.’P TIE bismuth i s d e p o s i t e d on .a pendent mercury drop e l e c t r o d e from H C I s o l u t i o n s i n which copper i s masked with t h i o c y a n a t e , and measured d u r i n g a n anodic scan. A s p e c t r o g r a p h i c method a% a t l e a s t e q u i v a l e n t s e n s i t i v i t y w a s a l s o developed; however, i t i n c o r p o r a t e s a p r e c o n c e n t r a t i o n by e x t r a c t i o n w i t h d i t h i z o n e and r e q u i r e s Parge s a l t smples.

6 3.3

.k.&j

Research a n d / o r development s t u d i e s i n t h e area of a n a l y t i c a l chemistry have been c a r r i e d o u t i n a l l of t h e areas o u t l i n e d i n she scope of t h i s a c t i v i t y . P r e s e n t l y , i n v e s t i g a t i o n s a r e being continued a l o n g l i n e s t h a t emphasize s u p p o r t of technology development w i t h i n t h e Program. Because e l e c t r o c h e m i c a l methods have proven most s u c c e s s f u l a t t h i s s t a g e of development f o r i n - l i n e measurement, c u r r e n t WOK^ i s concentrated l a r g e l y i n t h i s area. ‘%he s t a t u s of e a r l i e r work on t h i s a c t i v i t y i s summarized below.

6.3.3.1

.:&

S t a t u s of development

Electrochemical research

For t h e a n a l y s i s of m o l t e n - s a l t streams e l e c t r o a n a l y t i c a l t e c h n i q u e s such as v o l t a m e t r y and p o t e n t i a m e t r y a p p e a r t o o f f e r t h e most c o n v e n i e n t t r a n s d u c e r s f o r remote i n - l i n e measurements. V o l t a m e t r y i s based o n t h e p r i n c i p l e t h a t when a n i n e r t e l e c t r o d e is i n s e r t e d i n t o a molten s i l t and s u b j e c t e d t o a changing v o l t a g e r e l a t i v e to t h e s a l t p o t e n t i a l , negl i g i b l e c u r r e n t w i l l f l o w u n t i l a c r i t i c a l p o t e n t i a l i s reached at which one o r more of t h e i o n s ~ ~ d e r g o eans e l e c t r o c h e m i c a l r e d u c t i o n o r oxidaThe p o t e n t i a l a t which t h i s r e a c t i o n t a k e s p l a c e is c h a r a c t e r i s t i c tion. of the p a r t i c u l a r i o n o r i o n s . I f t h e p o t e n t i a l i s v a r i e d l i n e a r l y w i t h t i m e , t h e r e s u l t i n g c u r r e n t - v o l t a g e curve f o l l o w s a p r e d i c t a b l e p a t t e r n i n which t h e c u r r e n t r e a c h e s a d i f f u s i o n - l i m i t e d maximum v a l u e t h a t i s d i r e c t l y p r o p o r t i o n a l t o t h e c o n c e n t r a t i o n of t h e e l e c t r o a c t i v e i o n OK FOILS

6-12

Basic v o l t a m e t r i c s t u d i e s have been made on c o r r o s i ~ np r o d u c t i o n s i n the MSRE f u e l s o l v e n t , LiF-BeP2-ZrP422-25 and i n t h e proposed c o o l a n t salt, KaBF4-MaF.24-26 Most of t h i s work i s concerned w i t h the d e t e r mination of o x i d a t i o n states o f the elements, t h e most s u i t a b l e e l e c t r o d e materials f o r t h e i r a n a l y s i s and t h e b a s i c e l e c t r o c h e m i c a l c h a r a c t e r i s t i c s of each element. It has been shown t h a t r e l a t i v e l y high c o n c e n t r a t i o n s ( t y p i c a l l y , 20 ppm) c a n b e estimate d i r e c t l y from t h e h e i g h t of t h e v o l t a m e t r i c waves. Lower concentr t i o n s can be measured u s i n g the technique of s t r i p p i n g voltammetry through o b s e r v a t i o n of t h e c u r r e n t produced when a c o r r o s i o n p r o d u c t i s s x i d i z e d from a n e l e c t r o d e on which i t has p r e v i o u s l y been p l a t e d . 2 7 O d y Iimited s t u d i e s o f the s t r i p p i n g technique have been made i n molten f l u o r i d e s a l t s . ~

A v o l t a m e t r i c method has been developed f o r t h e d e t e r m i n a t i o n of U3*/U4+ his method i n v o ~ v e st h e measurement of ~e r a t i o i n t h e WRE f u e l . l 5 potentid diffeb-ence between t h e e q u i l i b r i u m p o t e n t i a l Sf t h e m e l t , measured by a n o b l e e l e c t r o d e , and t h e v o l t a m e t r i c e q u i v a l e n t of t h e s t a n d a r d p o t e n t i a l of t h e U5c/U4* couple. The r e l i a b i l i t y of the method w a s v e r i f i e d by comparison with v a l u e s that were o b t a i n e d s p e c t - ~ o p h o t ~ m e t r i c a l l y 2 8 T h i s d e t e r m i n a t i o n has been completely automated with which operates the v o l t a m e t e r , analyzes t h e d a t a u t e s t h e Y3d/Y4* r a t i o . Recently, t h e method w a s used to deter/u4+ r a t i o s i n a thorium b e a r i n g f u e l s o l v e n t , LiF-BeP2-ThFq (60-20-12 mole R a t i o s c o v e r i n g t h e r a n g e o f 10-5 t o >Po- w e r e measured d u r i n g the r e d u c t i o n of t h e f u e l i n a f s r c e d - c o n v e c t i o n l o o p (FCL-2b). The d a t a , n o t y e t completely analyzed, s u p p o r t the r e l i a b i l i t y sf t h e m e t h ~ din t h i s medium. e

x>.

Because t h e f u e l p r o c e s s i n g operation3o p r e s e n t s the p o s s i b i l i t y f o r i n t r o d u c i n g biSTiUth i n t o t h e f u e l , a method f Q P biSITXIth deterlldrtatiOn is r e q u i r e d . The r e d u c t i v e behavior s f B i 3 + was c h a r a c t e r i z e d i n L i F B ~ F Z - Z H P ~ , and ~ ~ i t w a s found t h a t i t i s r a t h e r e a s i l y reduced t o the 1. A s an i m p u r i t y i n t h e f u e l s a l t , bismuth will probably be p r e s e n t i n t h e metallic s t a t e , s o t h a t some o x i d a t i v e p r e t r e a t m e n t of t h e m e l t will be ~ - ~ ~ e s sbaerf oyr e a v o l t a m e t r i c determination of bismuth can be p ex-f o rmed *

me measurement of t h e c o n c e n t r a t i o n of p r o t o n a t e d species i n the proposed E B R c o o l a n t s a l t i s o f i n t e r e s t because of the p o t e n t i a l u s e of the c o o l a n t f o r the containment of t r i t i u m . The measurement could a l s o b e used t o e v a l u a t e t h e e f f e c t of proton c o n c e n t r a t i o n s on c o r r o s i o n rates and as a p o s s i b l e d e t e c t i o n technique f o r steam g e n e r a t o r l e a k s . A r a t h e r unique e l e c t r o a n a l y t i c a l technique t h a t i s s p e c i f i c f o r hydrogen W ~ S i n v e s t i g a t ~ ~ 2 5 J 1 he method is based on the d i f f u s i o n of hydrogen i n t o an evacuated p a l l a d i m - t u b e e l e c t r o d e when NaBP4 melts are electrolyzed a t a c o n t ~ - ~ E %p ed o t e n t i a l . The p r e s s u r e g e n e r a t e d i n t h e electrode i s a s e n s i t i v e measure sf protons a t ppb c o n c e n t r a t i o n s , The technique o f f e r s the advantages sf s p e c i f i c i t y , a p p l i c a b i l i t y t o in-Pime a n a l y s i s , and t h e p Q s s % b i l i k ySf if lTKe%%Urementof tri%iUill-tO-hydPOgen P a t h s in t h e coolant b y c o u n t i n g t h e sample c o l l e c t e d from the evacuated t u b e . Measurements by this technique, t ~ g e t h e rwith o b s e r v a t i o n s i n other areas

i . . . . w

e..:.:.:. . -,

6-14 o f a n a l y t i c a l r e s e a r c h , has l e d t o t h e d i s c o v e r y t h a t at l e a s t two %oms sf combined hydrogen a r e p r e s e n t i n NaBF4 m e l t s . In a d d i t i o n to i n f r a r e d - a c t i v e BP3OM, which i s n o t e a s i l y reduced, a more l a b i l e e l e c t r o a c t i v e s p e c i e s i s p r e s e n t i n e q u i l i b r i u m with a condensibbe s p e c i e s i n the gas phase. En a l l e l e c t r o a n a l y t i c a l measurements i t is a d i s t i n c t advantage to have an i n v a r i a n t r e f e r e n c e p o t e n t i a l t o which o t h e r eleet r o c h m i e a l r e a c t i o n s may be r e f e r r e d on a r e l a t i v e p s t e n t i a l scale. A p r a c t i c a l r e f e r e n c e e l e c t r o d e must be f a i r l y rugged and of u n i t constrract i s n . ‘Ehe mjor problem w a s t o f i n d non-cond~~ting materials which would b e compatible with f l u o r i d e m e l t s . S u c c e s s f d measurements were performed w i t h a PJiINiFZ e l e c t r o d e , i n which t h e r e f e r e n c e s o l u t i o n (LiP-13eF2 s a t u r a t e d with N S ~ ) i s c o n t a i n e d w i t h i n a s i n g l e - c r y s t a l ~ a cup ~ 3 32 9 3 3 Standard e l e c t r o d e p o t e n t i a l s w e r e determined f o r s e v e r a l rnetal/metal-fon c o u p l e s which w i l l b e p r e s e n t in t h e r e a c t o r s a l t streaws.28 ~ h e s e e l e c t r o d e p o t e n t i a l s p r o v i d e a d i r e c t measure O F t h e r e l a t i v e thermsdynamic stability of electroaetive species in t h e m e l t s . This information can be used in e q u i l i b r i u m c a l c ~ l a t i o n sto determine which i o n s would be expected t o be p r e s e n t a t d i f f e r e n t melt p o t e n t i a l s .

6.3.3.2

:.&

Because molten f l u o r i d e s react with t h e usuaP3.y employed l i g h t t r a n s m i t t i n g glasses, special c e l l d e s i g n s have been developed f o r t h e s p e c t r o The pendent-drop teshmique3 t h a t photometric examination of W B R m e l t s w a s f i r s t developed was l a t e r r e p l a c e d with t h e c a p t i v e - l i q u i d c e l l 3 5 i n which m l t e ~salts are c o n t a i n e d by v i r t u e of t h e i r s u r f a c e tensisn, s o t h a t no window material i s r e ~ g ~ i r e d .A concept has been proposed f o r the u s e of this c e l l i n an i n - l i n e system.36 Although t h e l i g h t path l e n g t h through a salt i n a c a p t i v e - l i q u i d c e l l i s d e t e r m i n a b l e , i t i s not f i x e d . The need f o r a f i x e d p a t h l e n g t h promoted the d e s i g n and which f a b r i c a t i o n of a g r a p h i t e c e l l having s m a l l diamond-plate h a s been used s u c c e s s f u l l y i n a number s f res-rch a p p l i c a t i o n s . Another fixed-path-length c e l l which i s s t i l l i n t h e development s t a g e makes use of a porous m e t a l foil38 t h a t c o n t a i n s a number of s m a l l i r r e g u l a r p i t s formed e l e e t s o c h e d e a l l y ; many of t h e pits are e t c h e d completely through t h e f o i l 9 so t h a t light can b e t r a n s m i t t e d through t h e m e t a l . Porous m e t a l made from HasteIBoy N h a s been purchased t o t e s t i t s u s e f o r c e l l construction

The latest i n n o v a t i o n i n eel$ d e s i g n i s a n o p t i c a l probe which l e n d s itself ts a sealable i n s e r t i o n i n t o a molten s a l t stream.39 he probe makes use of m u l t i p l e i n t e r n a l r e f l e c t i o n s w i t h i n a s l o t o f a p p r o p r i a t e width cut t h ~ o ~ gsome a p o r t i o n OS t h e i n t e r n a l l y r e f l e c t e d l i g h t beam.39 Burslng measurements t h e s l o t would b e below t h e s u r f a c e of t h e molten s a l t and would provide a known p a t h l e n g t h for a b s o ~ b a ~ measurements. ~e It i s b e l i e v e d t h a t t h e probe could b e made of LaF3 FOP m e ~ s u r m e n t s I n NalSF4 streams. Spectrophotometric studies of uranium i n t h e +3 o x i d a t i o n s t a t e have shown that t h i s method i s a l i k e l y c a n d i d a t e for i n - l i n e d e t e r m i n a t i o n of Y3* i n t h e reactor fuels40$4’ An extremely s e n s i t i v e a d s o r p t i o n peak

6-14

for ~ 4 +( 4 2 ) may be useful f o r monitoring r e s i d u a l uranium i n d e p l e t e d p r o c e s s i n g streams. Q u a n t i t a t i v e c h a r a c t e r i z a t i o n s , i n c l u d i n g a b s o r p t i o n peak p o s i t i o n s , peak i n t e n s i t i e s , and t h e assignment of s p e c t r a , have U0229, Cu2+, Mn2*, Mn3*, Co2+, been made f o r N i 2 + $ Fe2*, Cr2*, Cr3+ No3+$ C 1 - 0 4 ~ " Pa4+, ~ $u3*, Pr3+, Nd3+: Srn3', E$+, and Ha3+. Semiquantit a t i v e c h a r a c t e r i z a t i o n s i n c l u d i n g a b s o r p t i o n peak p o s i t i o n s approximate have a l s o been made I n v e s t i g a t i o n of p r o t o n a t e d s p e c i e s i n t h e proposed c o o l a n t w e r e made. Evidence f o r the e x i s t e n c e of hydrogen-containing i m p u r i t i e s i n NaBF4 was f i r s t o b t a i n e d from n e a r - i n f r a r e d s p e c t r a of the molten s a l t and i n mid-infrared s p e c t r a of p r e s s e d p e l l e t s of t h e c r y s t a l l i n e material . 4 3 Ill dC?t@riUDleX@hallge eXperiIWllts attempted i n fluOrobQKat€?m e l t s , bJ0 sensitive a b s o r p t i o n peaks corresp~nding to BF30I-i- and BF40B- were ident i f i e d . mere w a s no e v i d e n c e t h a t deuterium would exchange with B F ~ O H - , r a t h e r , BP$lD- w a s g e n e r a t e d via a redox r e a c t i o n w i t h i m p u r i t i e s in t h e melt.44 T h e a b s o r p t i o n s p e c t r a of several o t h e r s p e c i e s have been obs e r v e d i n f l u o m b o r a t e m e l t s . 4 5 Work on s p e c t r o p h s t o m e t r i e methods is also p r o v i d i n g d a t a f o r t h e i d e n t i f i c a t i o n and d e t e r m i n a t i o n of s o l u t e species i n the v a t . 2 ~melts ~ ~ o f interest for t h e f u e l s a l t p r o c e s s i n g system - 2 5

6.3.3.3

T r a n s p i r a t i o n and gas a n a l y s i s

t h e t r a n s p i r a t i o n approach o f f e r s t h e advantage of l o c a t i n g t r a n s d u c e r s f o r e f f l u e n t gas a n a l y s i s outside t h e h i g h e s t r a d i a t i o n zones, t h e s e d e v i c e s w i l l s t i l l receive exposure from f i s s i o n - p r o d u c t gases and t h e i r d a u g h t e r s and p o s s i b l y from p a r t i c u l a t e r a d i o a c t i v e m a t e r i a l s , and thus they w i l l require remote o p e r a t i o n . The o n l y r e s e a r c h performed on such t r a n s d u c e r s has been on methods f o r b a t c h samples of the MSRE f u e l . The e l e c t r o l y t i c m o i s t u r e monitor w a s demonstrated t o p r o v i d e more than adequate s e n s i t i v i t y f o r t h e measurement of water from t h e h y d r o f l u o r i n a t i o n method f o r o x i d e and t o have a d e q u a t e t o l e r a n c e f o r operation a t the a n t i c i p a t e d r a d i a t i o n levels.46 A method has been developed f o r t h e remote measurement of micromolar q u a n t i t i e s o f HF g e n e r a t e d by h y d r ~ g e ~ ~ t iofo nf u e l samples u s i n g a thermal-condwtiv5t-j method a f t e r p r e c o n c e n t r a t i o n by t r a p p i n g on NaF 4 0

Commercial g a s c h ~ o tQgKaghic CoIElpOnentS f o r hig%l-SenSitiv~ty EleaSUrC3IEllt of permanent g a s contaminants are n o t expected t o be a c c e p t a b l e a t t h e Valves c o n t a i n e l a s t o m e r s which r a d i a t i o n levels o f t h e M B R o f f - g a s . are s u b j e c t t o r a d i a t i o n damage and whose r a d i o l y s i s p r o d u c t s would contaminate t h e carrier gas The more sensitive d e t e c t o r s g e n e r a l l y depend on i o n i z a t i o n by weak r a d i a t i o n s o u r c e s and would o b v i o w l y be a f f e c t e d by sample a c t i v i t y . A p r o t o t y p e of a n all-metal sampling valveb8 has been c o n s t r u c t e d t o e f f e c t 6-way, double-throw s w i t c h i n g of gas A stream with closulpe e f f e c t e d by a p r e ~ s ~ l p e - a ~ t metal ~ ~ ~ t ediaphragm. d helium breakdown d e t e c t o r was found t o be c a p a b l e of measuring sub-ppm c o n c e n t r a t i o n s o f permanent gas i m p u r i t i e s in helium. U s e of this det e c t o r in a simpbe c h r o m t o g r a p h on t h e purge gas of a n i n - p i l e c a p s u l e

<.... .x.;

k.,

6-15

t e s t (MTR-47-6) demonstrated t h a t i t w a s n o t a f f e c t e d by r a d i o a c t i v i t y . 4 9 I r o n i c a l l y , subsequent tests with a more h i g h l y p u r i f i e d carrier gas r e v e a l e d s p o r a d i c a l l y n o i s y o p e r a t i o n caused by u n s t a b l e d i s c h a r g e s 48 T e s t s t o circumvent t h i s d i f f i c u l t y by c o n t r o l l e d i m p u r i t y a d d i t i o n s w e r e suspended because of h i g h e r p r i o r i t y p r o b l e m . The a n a l y s i s of t h e c o o l a n t cover gas i n v o l v e s less r a d i o a c t i v i t y b u t Methods are b e i n g i n v e s t i g a t e d f o r t h e more complex chemical problems d e t e r m i n a t i o n of condensable material t e n t a t i v e l y i d e n t i f i e d as BF3 h y d r a t e s and h y d r o l y s i s p r o d u c t s 5 0 and f o r o t h e r f o r m of hydrogen and tritium. "Dew-point" and d i f f u s i o n methods o f f e r p r o x i s e f o r such measurements An improved Karl F i s c h e r c o u l o m e t r i c t i t r a t o r w a s developed t o p r o v i d e c a l i b r a t i o n measurements of ate^" in both s i m u l a t e d and a c t u a l cover gas samples. e

6.3.3.4

In-line applications

Tkae f i r s t s u c c e s s f u l chemical a n a l y s i s of a flowing molten f l u o r i d e s a l t streams2 w a s demonstrated by measuring U3*/U4+ r a t i o s i n a loop being o p e r a t e d t o determine t h e e f f e c t of s a l t on HastePlsy N under b o t h oxid i z i n g and reducing c o n d i t i o n s . The test f a c i l i t y w a s a H a s t e l l o y M thermal-convection l o o p (NCL-2l) i n which LiP-BeF2-ZrF4-UFt+ c i r c u l a t e d a t a b o u t f i v e l i n e a r f e e t p e r minute. The a n a l y t i c a l t r a n s d u c e r s w e r e p l a t i n u m and i r i d i u m e l e c t r o d e s t h a t were i n s t a l l e d i n a surge t a n k where t h e t e m p e r a t u r e w a s c o n t r o l l e d a t 65Q'C. r a t i o w a s monitored o v e r a p e r i o d of several months on a completely automated b a s i s . A new c y c l i c voltammeter, which p r o v i d e s several new c a p a b i l i t i e s f o r e l e c t r o c h e m i c a l s t u d i e s on m o l t e n - s a l t s y s t e m , w a s designed f o r u s e with t h i s system. The v o l t a m e t e r can b e d i r e c t l y o p e r a t e d by a BDP-8 t y p e c o q u t e r . 5 3 A P I B P - ~ I computer w a s used t o c o n t r o l t h e a n a l y s i s system, a n a l y z e t h e experimental o u t p u t , make t h e n e c e s s a r y c a l c u l a t i o n s , and p r i n t o u t t h e r e s u l t s . A s e q u i l i b r i u m c o n d i t i o n s were being e s t a b l i s h e d , i n c r e a s e s i n the U3+ c o n c e n t r a t i o n w e r e followed as chromium w a s slowly d i s s o l v e d from t h e H a s t e l l s y N, c a u s i n g Uw t o b e reduced. P r e c i p i t o u s d r o p s i n t h e U3* c o n c e n t r a t i o n s w e r e observed due t o t h e i n t r o d u c t i o n of o x i d i z i n g contaminants when metal specimens were i n s e r t e d i n t o t h e m e l t . 54

The U3*/U4*

.... ....

.... .... a

.... ,M

:..ii. , .:.m

..... .:-

I n - l i n e measurements of U3+/?J4* r a t i o s and Cr2* c o n c e n t r a t i o n s are now b e i n g made i n f u e l salt i n a forced-convection l o o p (FCL-2b). Severe v i b r a t i o n problems d i s t o r t t h e waves and r e d u c e t h e accuracy of t h e measurements when t h e f u e l i s pumped a t high v e l o c i t y , b u t excellent voltammograms are o b t a i n e d when t h e pump i s stopped. W s p e c i a l s h i e l d e d e l e c t r o d e assembly i s b e i n g f a b r i c a t e d t o reduce t h e e f f e c t of v i b r a t i o n s i n t h i s and similar l o c a t i o n s . P r o v i s i o n s have been made i n t h e d e s i g n of t h e two e n g i n e e r i n g l o o p s , t h e Coolant-Salt Technology F a c i l i t y (CSTF) and t h e Gas-System Technology F a c i l i t y (GSTF) f o r t h e i n s t a l l a t i o n of a n a l y t i c a l t r a n s d u c e r s In

6-16 b r i e f studies i n t h e CSTP, r e d u c t i o n waves f a r Pe3'$ Fez+$ C r 2 + and p o s s i b l y Mo3* were observed a t concentrations from 20 to 100 ppm. First o r d e r decay o f a c t i v e p r o t o m w a s abserved to concentrations as l o w as a f e w ppb

6.4.1

Objective

The o b j e c t i v e of Task Group 5.1 i s t o develop e P e c t r s a n a l y t i c a % methods €OK the a n a l y s i s of f u e l , c o o l a n t and p r o c e s s i n g salt streams of t e s t , demOnStratiOT2, and power P @ a C t O r S on a SChedUle t h a t Will p e r m i t t h e US62

s f such methods in s u p p o r t of technology development a c t i v f t i e s f o r t h e KSBR program. Experience has shown that c e r t a i n e l e c t r o a n a l y t i c a l methods voltammetry and perhaps p o t e n t i o m e t q , o f f e r the m o s t c o n v e n i e n t transd u c e r s f o p i n - l i n e installation. Therefore, suck methods are expected t o r e c e i v e the m o s t usage - a t least e a r l y i n t h e d e ~ e l ~ p m ep~r otg ~ a r n . e d e ~ e l o p ~ ~of e ~pt rt a c t i c a l i n - l i n e methods must b e p r e ~ e d e dby t h e generation of basic data, such as s t a n d a r d e l e c t r o d e p s t e n t i a % s , d i f f u s i o n coefficients c s n d i t i o n s of reversibility, etc. by using s t h e r electrochemical techniques as chronopotentiometry, and c ~ ~ l ~ m e t a These ~ y . basic s t u d i e s will a l s o p r o v i d e valuable data on t h e behavior of i o n s i n m e l t s .

m.:.

6.4.2

Schedule

6.4.3 Operating fund requiremnts f o r this t a s k group a r e shown in Table 6 . 4 , 3 , 1 , and c a p i t a l equipment fund r e q u i r e m e n t s are shown i n Table 6 . 4 . 3 . 2 .

6-4.4

Facilities

Nost of t h e b a s i c s t u d i e s and i d t i a l development efforts will b e performed i n e x i s t i n g f a c i k i t f e s of r a t h e r modest requirements ( a n a l y t i c a l d a b o r a t o r i e s w i t h s t a n d a r d hoods). A s t h e program proceeds and materials involving p ~ ~ g ~ e ~ s i vmore e l y severe radiation hazards are encountered, space w i l l be used in e x i s t i n g alpha-containment f a c i l i t i e s e i t h e r at t h e Transuranium Laboratory o r t h e MSW a l p h a f a c i l i t y i n Building 4581. Ultimately, a n e x i s t i n g h o t c e l l facility such as t h e IEot-Cell S p e ~ t r ~ photometric I n s t a l l a t i o n may b e r e q u i r e d t o c o n t a i n melts emitting more penetrating r a d i a t i o n . A l s o , the e n g i n e e r i n g i n s t a l l a t i o n s in which i n - l i n e measurements are w d e serve as f a c i l i t i e s f o r this task group, b e c a m e t h e in-line measurements made t h e r e i n may reveal p r a c t i c a l deffciencies i n t h e methods I n a d d i t i o n , i n s t a l l a t i o n s containing large q u a n t i t i e s af salt sometimes present ~ p p o r t u n i t i e sfor s t a b i l i t y

w... >

Table 6.4.2.

5.1.1

Scb@dule for work fn Task Gmllp 5 ..I - In-liir&e

Fuel sa%t anal tpis 5.1.1.1 Y3$'/UT+

5.1.1.2 Ionic corrosionproducts 5.1.1.3 Bismt& 5.1.1.4 Tellmim 5.1.1.5 Profzacbiniuol 5.1.1.6 Plutonim

---

5 .b .I m7 Total corrosion products 5.1.1.8 Total uramim 5 .I ,I.9 Protonated species 5.1.1.10 Oxide 5.l.l.ll Miobilm 5.l.k.12 Chloride 5.1,l.U Noble-metal fission products 5.1.1.14 salt solobae IYssion products 5.1.B.15 Reference electrodes 5,1.2

LX1 analyses 5.1.2.1 Uranium 5.1.2.2 Ionic corrosPoQ products 5.1.2.3 Thorium 5.1.2.4 Plut~.aniuna 5.1.2.5 Pluorctde 5.1.2.6 Reference electPodas 5.1.2.7 Total. corrosion products 5.1.2.8 Oxide

electPocbenlica~

methods

___^

1981

1982

1983

198%

1985

1986

Table 6.4.3.1.

Operating fund requirements f o r Task Group 5.1 - I n - l i n e e l e c t r o c h e m i c a l methods (Costs i n 108O d o l l a r s ) F i s c a l year

5 * l e l F u e l salt a n a l sis 5.1.1.1 V3+/lJJ+ I o n i c c o r r o s i o n products 5.1.1.2 5.1.1.3 B ismt h 5.1.1.4 Tellurium Protactinium 5.1.1.5 Plutonium 5.1.1.6 T o t a l c o r r o s i o n products 5.1.1.7 T o t a l uranium 5.1.1.8 5.1.1.9 Protonated s p e c i e s 5.1.1.10 Oxide 5.1.1 .ll N i Q b i m 5 .l.1..12 Ch l or i d e 5.1.1.13 Noble-metal f i s s i o n products 5.1 .1.14 S a l t - s o l u b l e f i s s i o n pXQduCts 5 .1.1.15 Reference e l e c t r o d e s S u b t o t a l 5.1.1

5.1.2

L i C l analyses 5.1.2.1 Uranium 5.1.2.2 I o n i c c o r r o s i o n products 5.1.2.3 moriurm 5 .I .2.4 Plutonium 5.1.2.5 nuoriae 5.1.2.6 Reference electrodes

1975

1976

1977

12 10 11 12

1979

1980

1981

1982

1983

1984

1985

10 12 12 10 9 10 10

15 12 12 15 15

18 15

1978

10 15 5

10 10 6 6 7

f O

9 9 8

12 12

10 12 12

12 16 15

7 8 8

1986

1975

5.1.3

5.1.4 Total

5.1.2.7 5.1.2.8

oxide

Subtotal

5.1.2

Total

c0rrasion

5.1.3

Effects amdytical

operating

1978

radiatian transducers funds

1977

for

1979

B980

products

Coolant salt analysis 5. B. 3. B xoa-aic corroei.on prnducts 5.1.3.2 Pmtomted species 5 .I .% D3 Hydmgen isotopes 5.1.3.4 Redox buffer cauples 5.1.3.5 Reference e%ectrodes 5.1.%.6 Tbtal CorKasian products 5.1.3.7 oxygenated species Subtotal

P976

BQ 15 7

“a0 10 10 5 5 5

7 --I 39

-85

_---e--95

10 8 7 7 8 ao 5 55

Group

5.1

%lQ

1982

198%

4 12 50

12 1s 70

16 12 28

6 IQ 10

6 1Q

___ 26

P5Q

157

150

%%8

1984

198.5

60 90

40 70

8 7 8 8 8 8

-47

on electroTask

%98%

12%

14a

1986

Table 6.4.3.2.

5.1

Miscellaneous

Capital equipment fund requirements for In-line electrochemical analyses (costs in 1000 dollars)

items

5.1 Inert atmosphere box "60tal capital equipment funds far Task Group 5.1

Task Group 5.1 -

Fiscal

year

1975

19 76

1977

1978

IL979

25 -

1980

B981

1982

6-22.

s t u d i e s and c a l 5 b r a t i o n s f i a t are not f e a s i b l e with smll r e s e a r c h m e l t s . F i n a l p e r f e c t i o n of many of t h e i n - l i n e electrochemical methods w i l l be performed w i t h salt stream d e l i v e r e d by t h e A n a l y t i c a l Test F a c i l i t y (ATP) which i s discussed I n Subsection 6 .$

6.4.5

Task 5.1.1 Fuel s a l t a n a l y s i s

The predominant emphasis o f p a s t r e s e a r c h and development s t u d i e s has been on measurements i n f u e l o r i n m e l t s o f f u e l s o l v e n t composition. and t o -~ in situ These s t u d i e s have l e d t o s u c c e s s f u l i n - l i n e analyses52 measurements during the loading of f u e l p i n s under conditions r e q u i r i n g r a d i a t i o n containment.55 ~t is expected t h a t a s t r o n g emphasis on fuel a n a l y s i s will continue throughout t h e e a r l y stages of t h e program untF1 materials p r o b l e m are resolved. A l l of t h e earlier work w a s performed i n w e l t s of NSWE solvent c ~ m p o s i t i o nand many of t h e b a s i c measurements, p a r t i c u l a r l y d i f f u s i o n c s e f f i c f e n t s , w i l l have t o be repeated i n t h e thorium-bearing breeder c o ~ ~ ~ p o s i t i ~ Inns- l. i n e a p p l i c a t i o n s may s e r v e as screening tests t o eliminate some of t h e lengthy remeasurements. Measurecl an i n s u l a t i n g material i s found t h a t ments w i l l be g r e a t l y i ~ i p ~ o v e when i s f u l l y compatible with t h e f u e l . Such a material would permit a m a r e p r e c i s e d e f i ~ ~ i t i o of f l e l e c t r o d e areas and thus improve t h e p r e c i s i o n of the measurements. A search f o r b e t t e r i n s u l a t o r s w i l l be pursued througho u t the s p e c i f i c i n v e s t i g a t i o n s o u t l i n e d in t h e subtasks below. F l u o r i d e s a l t streams a s s o c i a t e d w i t h t h e processing system will a l s o be included i n this task g r ~ u p , s i n c e t h e i r p r o p e r t i e s will be similar t o those of the fuel.

6 4.5. I

Sub task 5 e 1.1 1

Beterminat i o n of Y3+8U4* r a t i o s

me f u e l s a l t redox p o t e n t i a ~ , as i n d i c a t e d by the ~ 3 9 1 r~a t4i o~, e x e r t s a profound i n f l u e n c e on t h e chemical and, perhaps, some p h y s i c a l properties of t h e f u e l . I t determines t h e corrosiveness of the f u e l with r e s p e c t t o s t r u c t u r a l materials, i n f l u e n c e s t h e d i s p o s i t i o n of c e r t a i n f i s s i o n products and tritium, and m y a f f e c t t h e s u r f a c e t e n s i o n and w e t t a b i l i t y of m e l t s . TIX v o l t a m e t r i c determination sf u~*/u" r a t i o i s t h e most f u l l y developed of the p r e s e n t i n - l i n e e l e c t r o a n a l y t i c a l methods and has been p r o f i t a b l y a p p l i e d t o i n - l i n e and i n s i t u measurements. Although t h e method has not y e t been s t u d i e d thoroughly i n MSBR fuel. salt, i t should be g e n e r a l l y a p p l i c a b l e t o any m e l t i n which rev e r s i b l e r e d u c t i o n waves can b e recorded. En f a c t , waves recorded r e c e n t l y during i n - l i n e measurements in a t h o ~ i ~ - b e a r P nfgu e l s a l t i n a forced-convection h o p e x h i b i t no q u a l i t a t i v e d l f f e ~ e n c e sf ~ o mt h o s e obtained earlier i n MSRE f u e l s a l t . The p r e c i s i o n of t h e method i s e x c e l l e n t ; r e p r o d u c 2 b i l i t y of 2 p e r c e n t was obtained i n MSRE m e l t s during automated o p e ~ a t i o nwith d i g i t a l moo thing and averaging of t h e voltammeter output. The accuracy of t h e method i s not as w e l l e s t a b l i s h e d . It has been found t h a t t h e p o t e n t i a l devel~pedby d i f f e r e n t noble-metal . e l e c t r o d e s may vary by as much as 15 m when i n s e r t e d into t h e s a m e m e l t . mis w o d d correspond t o an e r r o r i n ~ 3 * / ~ 4 +r a t i o measurements of about

6-23

20 p e r c e n t . Other p o t e n t i a l s o u r c e s of e r r o r i n c l u d e EW drops r e s u l t i n g from t h e r e s i s t a n c e of t h e m e l t OK of e l e c t r o d e l e a d s , j u n c t i o n p o t e n t i a l s , and d i s t o r t i o n of t h e r e d u c t i o n waves caused by m e l t flow p a t t e r n s o r d e p o s i t s on t h e e l e c t r o d e s . These v a r i a b l e s are expected t o i n t r o d u c e o n l y s m a l l and perhaps compensating e r r o r s , SQ t h a t t h e accuracy of t h e method i s w i t h o u t doubt a d e q u a t e f o r p r e s e n t usage i n measuring and cont r o l l i n g t h e redox p o t e n t i a l of f l u o r i d e s a l t s i n t e c h n o l o g i c a l e x p e r i ments. For f u t u r e a p p l i c a t i o n s , s u c h as measuring t h e charge b a l a n c e of a n o p e r a t i n g r e a c t o r t o determine t h e o x i d a t i v e e f f e c t of f u e l burn-ups t h e h i g h e s t p o s s i b l e accuracy will b e needed. ,..... ,.,., -

.... .%

..... .%

The e f f e c t s of a l l conceivably s i g n i f i c a n t v a r i a b l e s w i l l be s t u d i e d t o e s t a b l i s h t h e i r impact on t h e a c c u r a c y of t h e method. Where p o s s i b l e , e r r o r s will b e e l i m i n a t e d OK q u a n t i f i e d f o r c o r r e c t i o n , and s p e c i f i c a t i o n s w i l l b e e s t a b l i s h e d f o r t h e i n s t a l l a t i o n and o p e r a t i n g requirements n e c e s s a r y f o r a p a r t i c u l a r l e v e l of accuracy and p r e c i s i o n . When pract i c a l , many of t h e s e s t u d i e s w i l l b e performed d u r i n g i n - l i n e measurements t o p r o v i d e more r e a l i s t i c e v a l u a t i o n c o n d i t i o n s and t o e f f e c t economies i n o v e r a l l Program e f f o r t . It i s l i k e l y t h a t f i n a l p e r f e c t i o n of t h e method w i l l r e q u i r e t h e u s e of c l o s e l y c o n t r o l l e d s a l t streams i n t h e A n a l y t i c a l T e s t F a c i l i t y (Task Group 5 6 ) e

6.4.5.2

.... ,.w

.... ......,

Subtask 5.1.1.2

Determination of i o n i c c o r r o s i o n p r o d u c t s

Methods w i l l b e r e q u i r e d f o r t h e continuous d e t e r m i n a t i o n of ppm concent r a t i o n s of c o r r o s i o n product i o n s , p a r t i c u l a r l y chromous ions, i n f u e l streams i n o r d e r t o monitor c o r r o s i o n of r e a c t o r f u e l systems and t o assist in b a s i c s t u d i e s of c o r r o s i o n mechanisms. Complete e l e c t r o c h e m i c a l c h a r a c t e r i z a t i o n s 7 9 2 3-25 have been c a r r i e d out i n MSRE s o l v e n t s f o r i o n s t h a t might e n t e r a moderately o x i d i z i n g f u e l s a l t v i a c o r r o s i o n of ,'2iN Cr2*$ and Ti3' t i t a n i u m - m d i f k e d Bastelloy-N, s p e c i f i c a l l y : Fe2', and Ti4+. C o n c e n t r a t i o n s of t h e f i r s t t h r e e of t h e s e i o n s have been e s t i m a t e d d u r i n g i n - l i n e measurements; t h e measurement s f Cr2* i n a c t u a l f u e l m e l t s i s s u b j e c t t o i n t e r f e r e n c e from t h e a d j a c e n t uranium wave. The e l e c t r o a n a l y t i c a l chemistry of t h e s e i o n s w i l l b e c h a r a c t e r i z e d i n MSBR f u e l s a l t a l o n g w i t h molybdenum and t h o s e i s n s t h a t may b e generated by o t h e r a d d i t i o n s t o H a s t e l l o y N. Again, where p r a c t i c a l , i n i t i a l s c r e e n i n g s t u d i e s w i l l b e performed d u r i n g i n - l i n e measurements. Effob-ts w i l l b e made t o improve t h e r e s o l u t i o n of c l o s e l y a s s o c i a t e d waves and t h e accuracy of t h e measurements (now e s t i m a t e d a t 1 0 t o 20 p e r c e n t f o r t y p i c a l c o n c e n t r a t i o n s ) by proper s e l e c t i o n of e l e c t r o d e materials, b e t t e r d e f i n i t i o n of e l e c t r o d e areas, t h e u s e of p u l s e d and s t r i p p i n g t e c h n i q u e s , Such and d i g i t a l p r o c e s s i n g of t h e r e s u l t i n g d a t a (see Task Group 5.7). improvements would p e r m i t more r a p i d d e t e c t i o n of changes i n c o r r o s i o n rates and, perhaps, t h e l o c a t i o n of areas of more r a p i d a t t a c k i n m u l t i loop systems.

6-24 6.4.5.3

Subtask 5.1.1.3

Determination of bismuth

Because bismuth c o d d damage nickel-based s t r u c t u r a l materials, i t s conc e n t r a t i o n must b e maintained a t t o l e r a b l e levels i n the s a l t r e t u r n e d from the p r o c e s s i n g system. Continuous methods t h a t a r e s e n s i t i v e t o ppb levels of bismuth must b e developed t o monitor t h e e f f e c t i v e n e s s of bismuth removal s y s t e m . Electrochemical s t u d i e s i n MSWE solvents have shorn t h a t BIP3 i s reduced t o t h e metal a t a p o t e n t i a l more p o s i t i v e t h a n t h a t f o r t h e r e d u c t i o n sf n i c k e l w i t h evidence of a l l o y formation w i t h some e l e c t r o d e materials. I n voltammetry, r e d u c t i o n wave h e i g h t s are p ~ o p s ~ t i o n at ol t h e molar ~ o n c e n t r a t i s n sS € t h e r e d u c i b l e s p e c i e s . The h i g h e q u i v a l e n t weight of bismuth, t h e r e f o r e , makes i t h i g h l y improbable t h a t t h e needed s e n s i t i v i t i e s can b e achieved by d i r e c t voltammetric measurement. Although s t r i p p i n g t e c h n i q u e s can, I n t h e o r y , be extended t o almost any d e s i r e d c o n ~ e n t ~ a t i olne v e l i t a p p e a r s l i k e l y t h a t i n t e r f e r e n c e from the a d j a c e n t n i c k e l wave w i l l l i m i t this approach a t t h e N i / B i r a t i o s expected i n t h e fuel. The earlier studies a l s o showed. t h a t B ~ F Qd i s a p p e a r e d slowly f r o m f u e l s o l v e n t m e l t s , which w a s a t t r i b u t e d However, i n to r e a c t i o n w i t h o r a b s o r p t i o n by t h e c o n t a i n e r material.. view of r e c e n t l y reported data,56 the observed behavior may have r e s u l t e d from v s l a t i z a t i o n . I n most r e a s t o r streams bismuth will b e p r e s e n t as entrained metal p a r t i c u l a t e s . Since e l e ~ t r ~ ~ h e ~t e~c hi nsi aq ul e s do not respotbd t o p a r t i c u l a t e s , a n e c e s s a r y part of t h e a n a l y t i c a l development work w i l l Be t h e i n - l i n e ~ x i c l a t i o nof a l l forms of bismuth t o t h e t r i valent state

High p r i o r i t y w i l l b e a s s i g n e d t o e s t a b l i s h i n g the f e a s i b i l i t y of -~ in situ bismuth d e t e r m i n a t i o n s . Measurements w i l l be resumed w i t h the immediately a v a i l a b l e MSaE solvents i n a more impervious c o n t a i n e r ( g l a s s y carbon) than used p r e v i o u s l y , and work will shift s h o r t l y t o measurements w i t h MSBR f u e l s a l t when t h i s material i s a v a i l a b l e from s a l t p r o d u c t i o n activities. The route of B i P 3 d e p l e t i o n w i l l be e s t a b l i s h e d . I f t h e material i s volatized from t h e m e l t , a t r a n s p i r a t i o n a l a n a l y s i s approach w i l l be e ~ a l ~ t e(Subtask d 5.3.2.4). S t u d i e s w i l l b e m d e in melts CIXIe observed, t a i n i n g b a t h BiF3 and N i P 2 . If the a n t i c i p a t e d i n t ~ ~ f e r e n ei s t h e f o l l ~ w i n gapproaches f o r c i r c m v e n t i n g t h i s d i f f i c u l t y w i l l b e t e s t e d : (1) Search f o r an e l e c t r o d e material t h a t will s e l e c t i v e l y a l l o y bismuth and t h u s p r o v i d e t h e needed r e s o l u t i o n from n i c k e l , (2) removal of cod e p o s i t e d n i c k e l as N~(CQ)I,p r i o r to measurement of bismuth by s t r i p p i n g , and ( 3 ) f u r t h e r v o l t a m e t r i c r e d u c t i o n of d e p o s i t e d bismuth t o t h e bismuthide. 5 7 When e l e c t r o c h e m i c a l c h a r a c t e r i s t i c s are a d e q u a t e l y establ i s h e d f o r -~ i n s i t u measurements, homogeneous r e d u c t i o n of B i P 3 and reoxidation of t h e d i s p e r s e d a e t a l w i l P b e s t u d i e d . E f f o r t s w i t h i n t h e t a s k w i l l inclt.de e l e c t r o l y t i c o x i d a t i o n at porous e l e c t r o d e s and o x i d a t i o n s t u d i e s by t r a n s p i r a t i o n methods (Task 5.3.2). Unless unexpectedly s t a b l e d i s p e r s i o n s ~f bismuth i n salt can b e g e n e r a t e d , completion of o x i d a t i o n s t u d i e s m u s t await a v a i l a b i l i t y of t h e Analytical. T e s t F a c i l i t y (Task Grsup 5.6) e

6-25

6*4.5.4

Subtask 5.1.1.4

Tellurium s t u d i e s

Because evidence e x i s t s t h a t t e l l w i u m c o n t r i b u t e d t o i n t e r g r a n u l a r c o r r o s i o n of standard H a s t e l l o y N i n t h e MSRE, knowledge of i t s chemistry in f l u o r i d e s a l t s i s needed f o r t h e materials development program. &Ithough i t is not expected t h a t i n - l i n e e l e c t r o c h e m i c a l methods w i l l be p r a c t i c a l f o r measurement of t e l l u r i u m a t c o n c e n t r a t i o n s a n t i c i p a t e d F n a n NSR, p r i o r i t g i h a s been a s s i g n e d t o e l e c t r o a n a l y t i c a l c h a r a c t e r i z a t i o n of t e l l u r i u m species i n f u e l s~lventsi n o r d e r t o e s t a b l i s h meaningful c o n d i t i o n s f o r e v a l u a t i o n of the r e s i s t a n c e of modified H a s t e l l y N to a t t a c k by t e l l u r i u m . The d a t a o b t a i n e d (decomposition p o t e n t i a l s of t h e metal, d i f f u s i o n c o e f f i c i e n t s and s t a b i l i t y r a n g e s of d i v e r s e o x i d a t i o n states) w i l l b e sf v a l u e i n d e s i g n i n g and e x e c u t i n g experiments on development of modified H a s t e l l o y N. C h a r a c t e r i z a t i o n s t u d i e s have been s t a r t e d i n MSWE solvent, and work w i l l s h i f t s h o r t l y to MSBR f u e l s a l t . The d a t a o b t a i n e d i n these s t u d i e s will a l s o b e used t o assess the potent i a l f o r e l e c t r o a n a l y t i c a l measurement of t e l l u r i u m i n materials development experiments. Needed in-line s u p p o r t w i l l b e provided f o r r e s e a r c h and development s t u d i e s i n which t e l l u r i m c o n c e n t r a t i o n s a r e s u f f 5 , c i e n t I y h i g h €OK measurement. 6.4.5.5

,.:.x,j

....

Subtask 5 . l . 1 . 5

Determination o f p r o t a c t f n i m

I n o r d e r t o m a i n t a i n an o v e r a l l system doubling t i m e o f 119 y r s i n an MSBR, p r o t a c t i n i u m must b e c o n t i n u o u s l y removed on a c y c l e of about 10 days f r o m areas of h i g h n e u t r o n f l u x d e n s i t y . S e n s i t i v e i~-linemethods f o r i t s d e t e r m i n a t i o n w i l l b e r e q u i r e d t o monitor t h e e f f e c t i v e n e s s of t h e p r o t a c t i n i u m removal system. A t s t e a d y s t a t e pera at ion, t h e c o n c e n t r a t i o n of p r o t a c t i n i u m i n t h e f u e l w i l l be maintained by t h e p r o c e s s i n g system a t a b o u t one p e r c e n t of that sf uranium. Concentrations of this order can b e measured by p r e s e n t v o l t a m e t r i c t e c h n i q u e s , and expected improvements will p r o v i d e s u f f i c i e n t s e n s i t i v i t y to d e t e c t r e s i d u a l concentrat i o n s i n p r o c e s s i n streams, i f i n t e r f e r i n g waves a r e n o t encountered. No electroanalytical measurements have been made for protactinium because of t h e l a c k of a f a c i l i t y i n which a l p h a - e m i t t i n g materials c a n be used, b u r e s t i m a t i o n s of wave positions have been wade from themodymmic cons i d e r a t i o n s . ate Fa4+ t o Pa3+ r e d u ~ t i o nwave should o c c u r a t a more n e g a t i v e p o t e n t i a l than t h e ~ 3 *to U* wave and h o p e f u l l y w i l l tse r e s o ~ v e d from the ~ h 4 +t o ~ h ’ + wave which d e t e r m i n e s t h e melt limits. me paQ+ t o pas+ oxidatfon wave should be more c a t h o d i c than (precede) the n i c ~ c e l decomposition wave, H i Q t o MZ+, which i s u n l i k e l y t o be observed i n f u e l m e l t s ; b u t may be s u b j e c t t o i n t e r f e r e n c e from a n i r o n s t r i p p i n g wave. The p r o t a c t i n i u m o x i d a t i o n wave m y also b e complicated by d e p o s i t i o n of oxides since Pa205 2s one of t h e l e a s t s o l u b l e o x i d e s i n fluoride m e l t se

On the b a s i s of t h e s e c o n s i d e r a t i o n s , measurements of p r o t a c t i n i u m i n f u e l m e l t s may be d i f f i c u l t ; however, measuraents may b e p o s s i b l e a t j u d i e i s w l y s e l e c t e d points i n the p r o c e s s i n g system. The e f f l u e n t from t h e f l u o r i n a t o r w i l l c ~ n t a i nt h e same c o n c e n t r a t i o n of p r o t a c t i n i u m as the f u e l , b u t w i t h o n l y a b o u t e q u i v a l e n t q u a n t i t i e s of i n t e r f e r i n g aaran2um.

6-26 A l s o , oxide, i f p r e s e n t , w o d d b e s u b s t a n t i a l l y r e m v e d by f l u o r i n a t i o n . S i m i l a r l y , t h e c o n c e n t r a t i o n of p r o t a c t i n i u m i n t h e e f f l u e n t s a l t from t h e p ~ o t a e t i n i u r ne x t r a c t i o n s t e p w i l l b e e s s e n t i a l l y equal. t o t h a t i n t h e stream r e t u r n e d t o t h e r e a c t o r , b u t b e l a r g e l y f r e e of uranium, oxide, i r o n , and n i c k e l . Thus, t h e most s e n s i t i v e measurements can b e performed in this stream, which w i l l c o n t a i n t h e l o w e s t c o n c e n t r a t i o n of p r o t a c t i n i u m .

Electrochemical c h a r a c t e r i z a t i o n oE p r o t a c t i n i u m w i l l be c a r r i e d orat i n MSBR f u e l carrier s a l t when f a c i l i t i e s and materials a r e a v a i l a b l e . It i s l i k e l y t h a t work w i l l b e c a r r i e d out i n i t i a l l y d u r i n g I n s i t u a n a l y s e s i n sup o r t of b a s i c chemical r e s e a r c h t o d e t e r m i n e t h e f r e e energy of fie ~a /pa’+ couple. such i n v e s t i g a t i o n s would be performed i n a-facili e s i n Building 4501, and w s d d p r o v i d e e x p e r i e n c e i n e l e c t r o a n a l y t i c a l ~ e s a r c f non a - c o n t a i n i n g m e l t s and a l l o w development of c r i t e r i a f o r t h e d e s i g n of a n a p p r o p r i a t e a - f a c i l i t y f o r f u r t h e r e l e c t r o a n a l y t i c a l r e s e a r c h and development. When a n a l y t i c a l a - f a c i l i t i e s are a v a i l a b l e , more r e f i n e d studies o f p r o t a c t i n i u m w i l l b e made by u s i n g the most advanced e l e c t r o a n a l y t i c a l t e c h n i q u e s i n h i g h l y p u r i f i e d s o l v e n t and i n admixture w i t h r e a l i s t i c c o n c e n t r a t i o n s of expected i n t e r f e r e n c e s . These l a t t e r s t u d i e s m y l e a d to an a l t e r n a t e approach f o r t h e e l e c t r o a n a l y t i c a l measurement of traces of oxide i n MSBR f u e l s a l t .

E+

6.4.5.6

Subtask 5.1.1.6

Determination of plutonium

Plutonium w i l l b e p r e s e n t i n r e a c t o r f u e l s as a major c o n s t i t u e n t , i f PuF3 is used as a s t a r t - u f u e l , 01- i n trace c o n c e n t r a t i o n s i n a n MSBR o p e r a t i n g on t h e 2 3 2 ~ h - 2 3 & fuel c y c l e . At t h i s t i m e , no e l e c t r o a m l y t i e a l s t u d i e s of plutonium i o n s i n f l u o r i d e m e l t s have been made and t h e r e are a t p r e s e n t no imminent experiments w i t h i n t h e PER Program t h a t r e q u i r e t h e e l e c t r o a n a l y t i c a l d e t e ~ m i ~ ~ a t of i o nplutonium. When alphacontainment f a c i l i t i e s are e s t a b l i s h e d , t h e e l e c t r o c h e m i s t r y o f plbutonim w i l l be thorou ly s t u d i e d in breeder-composition m e l t s . P a r t i c d a r a t t e n t i o n w i l l b e g i v e n t o i n v e s t i g a t i o n of a r e v e r s i b l e s o l u b l e redox plutonium couple t h a t c o u l c ~serve as a n a l t e r n a t e t o the ~ 4 * / ~ 3 *voltammetric method f o r the measurement of t h e redox c o n d i t i o n of t h e f u e l . Plutonium i s expected t o be p r e s e n t predominately i n t h e t r i v a l e n t s t a t e and, i f a n o t h e r s o l u b l e o x i d a t i o n s t a t e can b e generated r e v e r s i b l y w i t h i n t h e s o l v e n t e l e c t r ~ l y s i slimits, t h e v o l t a m e t r i c t e c h n i q u e f o r r a t i o measurements can b e a p p l i e d . The p o s s i b l e i n t e r f e r e n c e of major and trace c o n c e n t r a t i o n s of plutonium w i t h o t h e r e l e c t r o a n a l y t i c a l a n a l y s e s w i l l be e v a l u a t e d . S t u d i e s w i t h plutonium w i l l be suspended a f t e r s u f f i c i e n t b a s i c d a t a has been a c q u i r e d t o e s t a b l i s h t h e f e a s i b i l i t y of an i n - l h e plUtQllietm a n a l y s i s RlethOd.

6.4.5.7

Subtask 5.1.1.7

Determination of t o t a l c o r r o s i o n p r o d u c t s

I n f e r e n c e s f ~ o ma n a l y t i c a l d a t a from t h e o p e r a t i o n of t h e K R E and from themodynamic c o n s i d e r a t i o n s i n d i c a t e t h a t t h e major f r a c t i o n of t h e more-noble c o r r o s i o n products such as i r o n and n i c k e l w i l l b e p r e s e n t as

(t;,i'

6-2 7 ....

....

... .... .<w

p a r t i c u l a t e metals i n a n MSBR. A s i g n i f i c a n t f r a c t i o n of chromium could b e i n c o r p o r a t e d i n t h e p a r t i c u l a t e s by a l l o y i n g . The measurement of t h e s e m e t a l l i c c o r r o s i o n p r o d u c t s w i l l be needed t o p r o v i d e a completely e f f e c t i v e system f o r monitoring c o r r o s i o n w i t h i n t h e f u e l system. Elect r o l y t i c t e c h n i q u e s w i l l b e i n v e s t i g a t e d as a means of c o n v e r t i n g t h e p a r t i c u l a t e matter t o measurable i o n s , perhaps w i t h coulometric i n t e g r a t i o n of t h e r e d u c t i o n c u r r e n t . E l e c t r o c h e m i c a l methods w i l l a l s o be used t o s u p p o r t o ~ i d a t f ~s tnu d i e s by chemical means (see Task 5 . 3 . 2 ) . Some of t h e e a r l y s t u d i e s w i l l b e made i n t h e GSTP which w i l l be equipped w i t h l a r g e p e n e t r a t i o n s f e r a n a l y t i c a l d e v i c e s . This e a r l y work w i l l p r o v i d e r e a l i s t i c samples i n which t h e t o t a l c o r r o s i o n product concent r a t i o n s w i l l b e e s t a b l i s h e d by r e p e a t e d e h e m k a l a n a l y s e s

6.4.5.8

Subtask 5.1.1.8

Determination of t o t a l uranium

The e l e c t r o a n a l y t i c a l measurement of t h e t o t a l c o n c e n t r a t i o n of uranium w i t h t h e p r e c i s i o n r e q u i r e d to maintain adequate i n v e n t o r y measurements w i t h i n t h e primary system a p p e a r s t o b e beyond t h e f o r e s e e a b l e c a p a b i l i t i e s of t h e s e t e c h n i q u e s . P r e c i s i o n s s u b s t a n t i a l l y b e t t e r than 50.1% would be needed t o d e t e c t bosses through d e p o s i t i o n t h a t could compromise t h e n u c l e a r s t a b i l i t y o f a r e a c t o r , and o t h e r methods w i l l b e developed f o r d e t e r m i n a t i o n of long-term r e a c t i v i t y b a l a n c e s (see S e c t i o n 1 2 ) . P r e s e n t l y , i t i s e s t i m a t e d t h a t i n a p p r o p r i a t e i n - l i n e system p r e c i s i o n s of 9%0% are a c h i e v a b l e . Measurements w i t h t h i s p r e c i s i o n could p r o v i d e u s e f u l d a t a i n some f l u o r i d e stream a s s o c i a t e d w i t h t h e p r o c e s s i n g system. Moreover, t h e p r e c i s i o n may be Tmproved t o perhaps kl% by u s e of p r e c i s e l y d e f i n e d e l e c t r o d e areas and by a p p l i c a t i o n o f d i g i t a l t e c h n i q u e s . P o t e n t i a l needs for i n - l i n e d e t e r m i n a t i o n of u r a n i m i n c l u d e t h e measurement of h i g h c o n c e n t r a t i o n s i n r e t u r n stream from t h e proce s s i n g system, r e s i d u a l c o n c e n t r a t i o n s i n p r o c e s s i n g stream from which t h e uranium i s removed by f l u o r i n a t i o n o r r e d u c t i v e e x t r a c t i o n , and trace c o n c e n t r a t i o n s i n waste s a l t streams. Improved techniques f o r defining electrode areas and r e d u c i ~ ~sga l t flow e f f e c t s w i l l b e used t o i n c r e a s e t h e a c c u r a c y and p r e c i s i o n of t h e measurement of moderate t o high c o n c e n t r a t i o n s o f uranium i n f l u o r i d e salts. Developments i n p u l s e d and s t r i p p i n g t e c h n i q u e s w i l l b e used t o i n c r e a s e t h e s e n s i t i v i t y of t h e measurements of trace c o n c e n t r a t i o n s . Techniques such as ckronocoulometry and c o n t r o l l e d p o t e n t i a l coulometry w i l l b e t e s t e d f o r a p p l i c a t i o n t o s a l t streams such as t h e e f f l u e n t from t h e p r o t a c t i n i u m e x t r a c t i o n s t e p i n which t h e uranium w i l l b e i n t h e t r i v a l e n t state.

6.4.5.9

Subtask 5.1.1.9

Determination of p r o t o n a t e d s p e c i e s

h e means of c o n t r o l l i n g tritium e m i s s i o n s from a molten salt r e a c t o r is. t o o p e r a t e w i t h t h e f u e l s a l t a t redox c o n d i t i o n s t h a t w i l l r e t a i n a mjor f r a c t i o n of t h e tritium i n a eombimed form and p r e v e n t d i f f u s i o n of tritium into t h e c o o l a n t s a l t . S i n c e t h e c o n c e n t r a t i o n of o x i d e i n

6-28

t h e salt w i l l n e c e s s a r i l y be %ow, it 5s expected t h a t t h e predominant t r i t i u m - c o n t a i n i n g s p e c i e s w i l l be TF rather than OTMeasurement of the r a t i o sf f r e e ts combined t r i t i u m would c o n t r i b u t e t o s t u d i e s of t r i t i u m d i s t r i b t u i o n i n f u e l salt systems, and w i l l perhaps be needed t o I Q O T l i t O r p r O t O ~ t e d . Species in t h e K e a C t Q P f u e l . Iht t h e e l e c t K O CQOlant s a l t s , %ask 5.1.3, it has been demonstrated- t h a t ppb conce t r a t i o n s of a n a c t i v e p r o t o n s p e c i e s , probably BF2 i n N a B F 4 , can be measured by c o n t r o l l e d - p o t e n t i a l e l e c t r o l y an evacuated p a l l a d i m electrode. Because t h e e l e c t r o l y z e d hydrogen can be readily reco%peredi n a c o u n t a b l e form, the approach i s a d a p t a b l e to the measurement sf active t r i t o n s i n t h e coolant. It has been proposed, b u t n o t y e t demonstrated, t h a t t h e r a t i o s f e l e m e n t a l t o combined hydrogen can b e determined by comparing t h e pressure rise rates within a n e l e c t r i c a l l y isolated e l e c t r o d e t o that w i t h i n a c a t h o d i c a l l y poised e l e c t r o d e .

..... ..... ~

h . .

6.4.5.lO

Subtask % . a b . l . l O

B e t e m i n a t i o n of oxfde

in-line a e t e m i n a t i s n 02 oxide is prime importance s i n c e o x i d e c o u l d cause p r e c i p i t a t i o n of p r o t a c t i n i u ~ iand ~ f i s s i l e and fertile materials from t h e f u e l . The s e n s i t i v i t y r e q u i r e ~ ~ nf ot r i n - l i n e measurements w i l l n o t b e known u n t i l the. oxide tolerance of the f u e l is w o r e a c c u r a t e l y established b u t could be a s l o w as 20 ppm. V O ~ ~ Z X I L T I tWe c~hKn~i q~ u e s respond t o the a c t i v i t i e s of d i s s o l v e d ions and are, t h e r e f o r e , unsuita b l e %Or t h e deteTXI%natfon Of t o t a l oxide i f SBBbe Qf the o x i d e i S present as a p r e c i p i t a t e . Thus, s e n s i t i v e e l e c t r o a n a l y t i c a l methods would be of greatest value d u r i n g normal o p e r a t i o n s a t oxide c ~ n c e n t ~ a t i below ~ns t h e t o l e r a n c e l e v e l of the f u e l and would complement rather than r e p l a c e t r a n s p i r a t i o n methods which would b e a p p l i c a b l e a t t h e h i g h e r oxide levels (Subtask 5 3 2 2 ) ~

In e a r l y experiments i n HSRE ss1v@nt, a cathodic wave w a s observed that w a s a t t r i b u t e d to the r e a u c t i o n of hydroxide t o oxide and hydrogen, and all anodic Wave resultiflg from the Oxidation Of o x i d e to OXygell. FUKtb-ner s t u d y of t h e s e waves w a s d i s c o n t i n u e d when i t was found t h a t they would b e s u b j e c t t o i n t e r f e r e n c e by the r e d u c t i o n and oxidation waves of UP4. studies of voltametrap of oxygen-eontainin species will be performed i n breeder f u e l c o ~ i p o s i t i o n ~ .Techniques for r e s o l v i n g oxide waves from i n t e r f e r i n g uranium e l e c t r o d e r e a c t i o n s w i l l b e evaluated ( d i g i t a l p r o c e s s i n g and/or selective eleetssdes such as s i l v e r f o r oxide). If

6-29

direct electrochemical nethods prove inapplicable a combination techniqkle Will b e d e v e b p e d , e . $ . , eleCtKQPysis Sf Blg%tS at CXgltrolled potential with s p a r g i n g and measurement o f liberated oxygen o r oxygen csmpomds by gas analytical techniques.

6.4.5.11

La&

Subtask 5.l.l.%16

Q e t e m i n a t i o n of n i ~ b i u m

0% t h e noble fission p r o d u c t s , niobium iS t h e m o s t s u s c e p t i b l e to Q X i d a tion. During the opeparion of the MS?..F,, major decreases in 9pHb concentration w e r e observed in the salt phase when adjustments o f f u e l redox potential were made by b e r y l l i u m additions 5 8 Thus niobium merits electrochemical investigation, both to assess i t s p ~ t e ~ ~ tas i a an l auxiliary index of fuel redox potential i n future r ~ i c t oand ~ ~to provide a tool f o r @ ~ d ~ a t i sf o nmIhE data. u 8 8 , niobium may be Used to modify the properties of Baatelloy N and thus could enter the fuel. as a corrosion product. A rather extensive electroanalytisal study of- niobium ow ever, interwas carried out in ea~lierresearch in ~m solvents 59 ference from traces of oxide in the melts prevented complete characteriz a t i o n . Electroanalytical studies of raiobiun w i l l be carried o u t in breeder solvents, from which oxide conta~~inati~n is I W K ~ carefully excluded, t o gain basic data and to assess the potential of the technique f ~ in-line r measurements. The effects of oxide a d d i t i o n s at levels below the melt tolerance will be studied and limited measurements in MSRE compositions w i l l be made for comparison and further understanding of e

WRE eqerience 6.4.5.12

Subtask 5.1.16.12

Determination of chloride

Chloride could enter the fuel via entrainment in bismuth streams from the rare earth removal s t e p of the processing system. It is anticipated that chloride can be tolerated at Bow levels in t h e fuel salt, and its concentration will be limited by IXSWQELB s f chloride during the f l u o r ,7 natisn step. However, a method w i l l be needed for determination of ~ h l ~ r i c t e im fluoride stream of the processing system. Ns measurements have yet been made, b u t the voltametric ~xidati~n of chloride i o n to the element appears to be %he m o s t promising electroanalytical approach. An eleetrsanalytical hvestigation will be carried out to determine whether a u s e f u l oxidation wave can be isolated f r o n t h e possible interfering waves of UFt+ or oxide. Selectively active electrodes will be sought; and, if wave resolution proves impractical, the potential sf a conbination of e l e c t r o l y t i c a d t r a ~ s p i ~ atechniques t i ~ ~ ~ w i l l be assessed. The effect of traces of chloride on the voltammetry of other i o n s in the f u e l will a l s ~be investigated as a possible approach to in-line measurement.

6-30 6 4.5 13 0

Subtask 5.1.1.13

S t u d i e s of n o b l e f i s s i o n p r o d u c t s

A t a n t i c i p a t e d c o n d i t i o n s of normal r e a c t o r o p e r a t i o n i t i s n o t expected t h a t f i s s i o n products more n o b l e t h a n m i o b i m w i l l b e i n i o n i c s o l u t i o n in s u f f i c i e n t c o n c e n t r a t i o n t o permit e l e c t r o a n a l y t i c a l measurement. P o s s i b l e e x c e p t i o n s may b e sub-zero o x i d a t i o n states similar t o t h o s e i n t h e case of t e l l u r i u m . E l e c t r o c h e m i c a l s t u d i e s w i l l p r o v i d e b a s i c chemical i n f o r m a t i o n such as redox p o t e n t i a l s and s t a b i l i z e d o x i d a t i o n s t a t e s under v a r y i n g redox c o n d i t i o n s . N o r e p r a c t i c a l i n f o ~ ~ ~ t ti hoa nt w i l l b e gained w i l l b e t h e e f f e c t s of such elements on a n a l y t i c a l methods. The n o b l e metals c o d d d e p o s i t o w e l e c t r o d e s and a l t e r t h e i r c h a r a c t e r i s t i c s o r p o s s i b l p c a u s e e l e c t r o d e damage. A roughly a n a l o g o ~ sproblem w a s encountered d u r i n g voltammetric measurements i n NaBF4 c o o l a n t , N i c k e l , a r e l a t i v e l y noble metal i n t h i s environment, formed an unexpected d e p o s i t on e l e c t r i c a l l y i s o l a t e d e l e c t r o d e s t h a t prevented a c c u r a t e v o l t a m e t r i c measurement of ~ e 3 +and active p r o t o n s . Basic e l e c t ~ o ~ h e m i c as tl u d i e s w i l l b e performed on a l o w p r i o r i t y f o r n o b l e f i s s i o n product elements i n b r e e d e r f u e l m e l t s a t v a r i o u s redox p o t e n t i a l s . F o r t h o s e cases i n which evidence of p o t e n t i a l problems i s o b t a i n e d , such as a n o m l o u s s t r i p p i n g phenomena, p l a n s f o r extended exposure of electrodes w i l l b e e s t a b l i s h e d , and t h e p h y s i c a l and e l e c t r o chemical p r o p e r t i e s of t h e exposed specimens will b e compared with t h o s e of f r e s h e l e c t r o d e s . The s t u d y w i l l b e extended t o o t h e r n o b l e trace elements t h a t m y b e present e i t h e r i n t h e i n i t i a l f u e l o r i n t r o d u c e d by c o r r o s i ~ nof s p e c i a l materials, such as p r e c i o u s metal b r a z i n g a l l o y s , o r transmutation products. 6.4.5.14

&...

Stnbtask 5.1.1.14 Determination of transuranium elements arid s a l t - s o l u b l e f i s s i o n p r o d u c t s

During t h e o p e r a t i n g life of a power r e a c t o r , d i v e r s e transuranium elements arid e l e c t r o p o s i t i v e f i s s i o n p r o d u c t s can b e p r e s e n t i n f l u o r i d e streams of t h e f u e l and p r o c e s s i n g s y s t e m i n c o n c e n t r a t i o n s s u f f i c i e n t f o r measurement or d e t e c t i o n by e l e c t r o a n a l y t i c a l t e c h n i q u e s . The concent r a t i o n o f some o f t h e s e elements may i n c r e a s e t h r o u g h s u t t h e o p e r a t i o n of t h e r e a c t o r b u t many w i l l r e a c h a s t e a d y - s t a t e level as a ~ e s k i l tof remsvd by the p r o c e s s i n g system. There a r e a t p r e s e n t no a n t i c i p a t e d needs f o r t h e i n - l i n e measurement of t h e s e elements i n a n o p e r a t i n g reactor, and i f such a need arises many of them can probably b e measured more e f f e c t i v e l y by y-spectrometry (Task Group 5 . 5 ) . However, d e t e c t i o n of some of t h e s e materials may b e r e q u i r e d i n the p r o c e s s i n g systems. Electroanalytical characterization studies w i l l generate data t o predict the e l e c t r o c h e m i c a l behavior of t h e s e elements and p r o v i d e t h e n e c e s s a r y i n f o m a t i o n f o r i n - l i n e s u p p o r t a c t i v i t i e s . A more i m p o r t a n t product of t h e basis s t u d i e s w i l l b e t o p e r m i t p r e d i c t i o n of p o t e n t i a l . i n t e r f e r e n c e Should v o l t a m e t r i c by t h e s e elements with e s s e n t i a l i n - l i n e methods. waves from such elements o c c u r a t p o t e n t i a l s s i d l a r t o t h o s e b e i n g measured a t trace c o n c e n t r a t i o n levels, t h e a c c u r a c y of needed measurements could be compromised. The measurement of p r o t a c t i n i u m i s

1151,

6-36

p a r t i c u l a r l y v u l n e r a b l e t o such i n t e r f e r e n c e . En a l l l i k e l i h o o d , eompensation can b e made €or moderate i n t e r f e r e n c e s by computer techniques b u t only i f t h e i n t e r f e r e n c e is a n t i c i p a t e d . A survey w i l l b e maintained of a l l trace elements t h a t could b e p r e s e n t

i n t h e f u e l a t e l e c t r o a n a l y t i c a l l y s i g n i f i c a n t levels. E l e c t r o a n a l y t i c a l s t u d i e s will b e performed f o r s u c h . e l w e n t s on a s c h e d u l e t b t w i l l be c o n s i s t e n t w i t h t h e needs of t h e Program. Unless s p e c i a l needs develop, t h i s w i l l be a l o w - p r i o r i t y a c t i v i t y . A s more s e n s i t i v e a n a l y t i c a l methods are developed t h e y w i l l b e used t o scan samples of t y p i c a l f u e l and s o l v e n t p r e p a r a t i o n s t o deterrnine whether o t h e r trace c o n s t i t u e n t s should b e i n c l u d e d i n t h i s a c t i v i t y . Methods will be e s t a b l i s h e d t o h a n d l e i n t e r f e r e n c e s t h a t are d i s c o v e r e d .

6.4.5.15

....

&!%!2

Subtask 5.1.1.15

Development s f r e f e r e n c e e l e c t r o d e s

A r e l i a b l e r e f e r e n c e e l e c t r o d e would o f f e r several advantages t o t h e i n l i n e a n a l y s i s program. For b a s i c s t u d i e s , a r e f e r e n c e e l e c t r o d e based on a redox couple of e s t a b l i s h e d thermodynamic p r o p e r t i e s can be used f o r t h e d i r e c t e s t i m a t i o n s f f r e e e n e r g i e s of formation of e l e c t r o a c t i v e s p e c i e s i n m e l t s . A r e f e r e n c e e l e c t r o d e of e s t a b l i s h e d r e l i a b i l i t y would make i t p o s s i b l e t o u t i l i z e d i r e c t p o t e n t i o m e t r i c measurements i n s t e a d of t h e v o l t a m e t r i c U3+/U4+ r a t i o f o r t h e d e t e r m i n a t i o n of redox p o t e n t i a l s i n t h e fuel. and t h e r e q u i r e d i n s t r u m e n t a t i o n would be s i m p l i f i e d . P o t e n t i o m e t r i c methods would a l s o be a p p l i c a b l e to processi n g streams from which uranium has been removed. I n such a p p l i c a t i o n s , a r e f e r e n c e e l e c t r o d e w ~ u l dp r e v e n t t h e p o s s i b i l i t y of t h e d s a s s i g n m e n t of peaks as a r e s u l t of a b r u p t changes i n t h e p o t e n t i a l of a quashr e f e r e n c e e l e c t r o d e w i t h redox c o n d i t i o n s i n t h e p r o c e s s i n g streams. It should b e noted t h a t o t h e r v o l t a m e t r i c f e a t u r e s , suck as m e l t limits, can serve as s u r r o g a t e s f o r a r e f e r e n c e e l e c t r o d e , b u t e x c e s s i v e u s e of such "mrkers" can c a u s e d e g r a d a t i o n of i n d i c a t o r e l e c t r o d e p e r f o m m e . The major problem i n development of r e f e r e n c e e l e c t r o d e s i n f l u o r i d e melts i s a s s o c i a t e d w i t h t h e u n a v a i l a b i l i t y of compatible i n s u l t i n g materials t h a t are needed t o e f f e c t i o n i c c o n t a c t between t h e m e l t s and I n s t a l l a t i o n requirements w i l l . a l s o l i m i t a n r e f e r e n c e compartments. i n - l i n e r e f e r e n c e e l e c t r o d e t o a smll d e v i c e of u n i t c o n s t r u c t i o n .

Keference e l e c t r o d e s f o r l i m i t e d service have been f a b r i c a t e d u s i n g a b o r o n - n i t r i d e membrane as a "salt bridge.'"' Devices t h a t o f f e r a c c e p t a b l y r e p r o d u c i b l e p o t e n t i a l s f o r p e r i o d s of months 3 2 have been developed by u s i n g a s i n g l e c r y s t a l lanthanum f l u o r i d e as a n i o n i c conductor. I n such d e v i c e s t h e r e f e r e n c e s o l u t i o n (a m e l t s a t u r a t e d w i t h NiP2) i s c o n t a i n e d i n a c a v i t y i n t h e crystal and d i s s o l u t i o n of t h e c r y s t a l by t h e s a l t is l i m i t e d by c o n t a c t w i t h t h e s a l t through a m e t a l f r i t . Problems w i t h t h i s e l e c t r o d e have i n c l u d e d o c c a s i o n a l c r a c k i n g of t h e lanthanum f l u o r i d e , presumably w d e r t h e r m a l stress, and d i f f i c u l t i e s , r e p o r t e d by others, i n r e t a i n i n g t h e r e f e r e n c e solieatfsn i n t h e c a v i t y . .pa

... ..... .:.!.x.

6-32

Lanthanum f l u o r i d e r e f e r e n c e e l e c t r o d e s w i l l be i n s t a l l e d i n t h e GSTE f o r t e s t i n g i n b r e e d e r f u e l under r e a l i s t i c c o n d i t i o n s . I n t h e s e tests, p o t e n t i o m e t r i c response w i l l be compared w i t h v a l u e s c a l c u l a t e d from U3ch.J4+ r a t i o s t o e s t a b l i s h t h e v a l i d i t y of t h e technique.

AR a n a l y s i s of the p r e s e n t r e f e r e n c e e l e c t r o d e d e s i g n w i l l be made to d e v i s e modifications t h a t w i l l reduce stresses and e n s u r e retention of A s b e t t e r i n s u l a t i n g materials are i d e n t i f i e d , t h e ~ e f e r e ~SoltatfoR. ~e t h e y w i l l b e i n c o r p o r a t e d i n t o e l e c t r o d e s of improved d e s i g n s . Existing and future e l e c t r ~ d e swill also be t e s t e d in melt. campositions orr respsnding t o processing streams.

6.4.6

Task 5.1.2

LiCl analyses

The metal t r a n s f e r p r o c e s s will be used t o remove high c r o s s - s e c t i o n raKe-43aKth Zission p r o d u c t s from MSBW f u e l carrier s a l t a f t e r t h e remval of u r a n i ~ mand p r o t a c t i n i m . T h i s will h v o l v e t h e selective clae~~L 9 -~e d~~l c t i o n06 m ~ ~ i a from l s t h e fuel s a l t i n t o liquid bismuth followed by back e x t r a c t i o n s i n t o molten lithium c h l o r i d e . I n a d d i t i o n to t h e K ~ I X e a ~ t h s ,t h e a l k a l i - m e t a l and a l k a l i n e - e a r t h fission p r o d u c t s and a number of t h e a c t i n i d e s w i l l t r a n s f e r to the L i C % . Also t h e use of t h i s versatile system f a r actinide ~ ~ c g r c i e i n t r o d u c e additional c o n s t i t u e n t s into t h e EfCk. E l e c t r o a n a l y t i c a l r e s e a r c h i n t h i s area w i l l b e carried o u t t o develop in-line methods t o monitor t h e accmul a t i o n of constituents i n s x i i n C O r r Q S i O n p r o d u c t s , UranfUIU, thOl-iUlIl, f l u o r i d e , and actinide elements, i n the l i t h i u m c h l o r i d e . It i s expected that t h e e l e c t ~ o d ei n s u l a t o r problem w 5 l l not be as s e v e r e as that encomtered in molten f % ~ o ~ i dand e s t h e r e f o r e a more p r e c i s e definitioffi of e l e c t r ~ d eareas w i l l b r i n g about a significant improvement in the p r e c i s i o n of v o l t a m e t r i c measurements. F u r t h e r refinement of the d a t a through pulsed v s l t a m e t r i c t e c h n i q u e s and digftal p r o c e s s i n g methods w i l l b e used t o implpo~epreeisioffi and s e n s i t i v i t y . In view of more p r e s s i n e l e c t r o a n a l y t i c a l research needs f o r f u e l and c o o l a n t s a l t a ~ a l y s e s , t h e l i t h i u m c h l o r i d e research i s n o t expected t o begin u n t i l FY 1978. I n t h e meantime, t h e l i t e r a t u r e w i l l be surveyed and p e r t i n e n t i n f o r m t i o n on c h l o r i d e melts which has been r e p o r t e d by 0 t h w~i l ~l be u t i l i z e d whenever a p p l i c a b l e . 111~0, t h e requirements f o r analyses i n t h i s medium are s p e c u l a t i v e t o a d e g r e e until f u r t h e r f u e l p r o c e s s i n g s t u d i e s a r e performed.

6.4.4;1

Subtask 5.1.2.1

Determination of uranium

&..

6-33 voltammetry o r perhaps chronocoulornetry. V o l t a m e t r i c techniques w2ll be used t o c h a r a c t e r i z e t h e e l e ~ t ~ ~ c h e ~ iofs t uranium ry i n chloride m e l t s by measuring b a s i c p r o p e r t i e s such as e l t ~ t r o d er e v e r s i b f l h t y , d i f f u s i o n c o e f f i c i e n t s , s t a b l e v a l e n c e states. men t h e e l e c t r o c h e ~ ~ t i s t ~ y of o t h e r s p e c i e s i n l i t h i u m c h l o r i d e has been studied, p r a c t i c a l details f o r i n - l i n e analysis w i l l be considered. This w i l l i n c l u d e t h e a p p l i c a t i o n O f p u l s e v o l t a m e t r i c techniques, d i g i t a l methods for data pb-ocessing and perhaps s t r i p p i n g t e c h n i q u e s t o p r o v i d e reso%ution from a d j a c e n t waves and improve t h e s e n s i t i v i t y of t h e measurement.

4.4.6.2

,.-,

Subtask 5 . 1 . 2 . 2

Determination of i o n i c ~orrosionp r o d u c t s

Lithium c h l o r i d e streams i n t h e p r o c e s s i n g system may contain traces of t h e typical c o r r o ~ i ~p rno d u c t s ( i r o n , chromium, and n i c k e l ) t h a t have been t r a n s f e ~ r e dfrom t h e f u e l , and a l s o c o r r o s i o n p r o d u c t s f r o m s t r u c t u r a l materials of t h e p r o c e s s i n g system. These l a t t e r materials may i n c l u d e molybdenum, t u n g s t e n , and tantalum, and perhaps d i v e r s e c o n s t i t u e n t s from b r a z i n g a l l o y s t h a t m y used t o joim r e f r a c t o r y m e t a l components. Because t h e l i t h i m c h l o r i d e m e l t s will be in contact w i t h solutions of e l e c t r s - p o s i t i v e metals i n bismuth, t h e m e l t s are expected t o be q u i t e reducing, and t h e c o n c e n t r a t i o n s f i o n i c c o r r o s i o n p r o d u c t s w i l l a s s u r e d l y b e low. A p o s s i b l e e x c e p t i o n i s sub-zero o x i d a t i o n states t h a t may b e s t a b l e i n t h e s e h i g h l y reduced m e l t s . The s t u d i e s i n this s u b t a s k will not b e r e s t r i c t e d t o r e d u c i n g melts, however, because t h e e l e c t r o a n a l y t i ~ amethoas ~ m y a l s o be a p p l i e d to the aeterI I l h A l t i O r P O f t o t a l c O K r O s i o I 3 prodblCtS after OXidatfoTl (See Subtask 5.1.2.7). Ebectroche~calc h a r a c t e r i z a t i o n of t h e s e s u b s t a n c e s has not been c a r r i e d out i n l i t h i m c h l o r i d e . O t h e r s , however, have r e p o r t e d 6 e l e c t r o c h e m i c a l measurements i n similar melts such as LICI-KCI U s e will be made of this i n f ~ ~ m a t i owherever n a p p l i c a b l e when t h e lithium ChloPide -L-eSeaKCh iS under Way. bt is expected t h a t SeparatfOnS and r e s o l u t i o n of v o l t a m e t r i c waves w5PB be comparable to t h a t observed i n the f u e l s a l t . The e l e c t r o c h e m i c a l p r o p e r t i e s of a n t i c i p a t e d c o r r o s i o n pereduet i o n s w f U be measured i n melts of v a r i o u s o x i d a t i o n p o t e n t i a l s . A p p l i c a t i o n will be made of a n o d i c s t r i p p f n g or p u l s e d voltametric t e c h n i q u e s to provide improved s e n s i t i v i t i e s . In-1Pne measurements on p r o c e s s streams will a l s o b e made whenever p r a c t i c a l for s c r e e n i n g purposes and for evaluation of the e l e c t r o a n a l y t i c a l methods.

6.4.6.3

Subtask 5.1.2.3

D e t e r d n a t i o n of t h o r i ~ m

The thorium which enters the l i t h i m c h l o r i d e w i l l i n large part be transferred t o t h e waste streams. It w i l l , therefore, be d e s i r a b l e to p r o v i d e i n - l i n e nethods f o r t h e measurement of thorium 5n t h e lithium chloride. The e q u i l i b r i u m c o n ~ m t ~ a t i oofn t h o r i m in t h e l i t h i m chloride is expected t o be q u i t e l o w ( ~ 3 . 3x mole fraction) It a p p e a r s that voltametric s t r i p p i n 0-r pulsed t e c h n i q u e s have t h e greatest p o t e n t i a l f o r t h i s d e t e r m i n a t i o n . F i r s t e f f o r t s will be to c h a r a c t e r i z e t h e eEectrode r e a c t i o n in molten lithium c h l s r i d e 2n r e s e a r c h m e l t s ; then work will be d i r e c t e d toward a d a p t i n g t h e mst promising t e c h n i q u e s t o in-line s i t u a t i o n s . a

6-34 6.4.4.4

Subtask 5.1.2.4

Determination of plutonfurn

E'lutoniula will normally be removed from t h e f u e l carrier s a l t i n t h e p r o t a c t i n i u m eduction s t e p and would not normally e n t e r t h e l i t h i m c h l o r i d e stream. However, some c a r r y o v e r m y b e expected, p a r t i c u l a r l y when t h e processing system i s used after s t a r t - u p wLth plutonium as a f u e l . The need f o r i n - l i n e measurements i s t h e r e f o r e n o t thoroughly established, b u t s u f f i c i e n t c h a r a c t e r i z a t i o n will be made to e s t a b l i s h the b a s i c e k c t K 0 C h e d s t K y O f pHutoniunr i n l i t h i k a ~ lChlQKide and datermine the f e a s i b i l i t y of i t s measurement. Ms known e l e c t r o c h e m i c a l d a t a e x i s t s i n this area. Cha~a~terfzation w i l l be done when a p p r o p r i a t e a%pha-csntainment f a c i l i t i e s are available.

6.4.6.5

Subtask 5.1.2.5

Determination of f l u o r i d e

The p r e s e n c e o f f l u o r i d e i n l i t h i u m c h l o r i d e stream of t h e p r o c e s s i n g system w i l l i n c r e a s e t h e q u a n t i t y of thorium t h a t i s t r a n s f e r r e d i n t o these StreaDE. QKder to reduce th0ribam h88@8, i t i s d e s i r a b l e to cQntPOl t h e ConCentratiQn O f f l U O K i d e at h W p e r c e n t a g e levels. The possibility of developing a f l u o r i d e i o n s p e c i f i c e l e c t r o d e d l k be i n v e s t i g a t e d . Single c r y s t a l LaP3 (a fluoride i o n conductor a t h i g h te~~pe~aturw e si)l l $e used to construct a s p e c i f i c i o n electrode provided i t s s o l u b i l i t y in l i t h i m c h l o r i d e i s not t o o high. Parameters to b e d e l i n e a t e d w i l l be Nemstian r e s p o n s e , r e s p o n s e t i m e , limits sf d e t e c t i o n , r e p r o d u c i b i l i t y of t h e potential. neasurements, and u s e f u l l i f e times of t h e LaF3 c r y s t a l %n molten lithium c h l o r i d e .

6.4.6.6

Subtask 5.1.2.6

Developmnt of r e f e r e n c e e l e c t r o d e s

Reference e l e c t r o d e s will be needed f o r b a s i c e l e c t r o a n a l y t i c a l s t u d i e s in molten lithium chloride. P o t e n t i o m e t r i c measurements will p r o v i d e a d i r e c t measure of the relative t h e m ~ d p a n n f cs t a b i l i t y of e l e ~ t ~ o a ~ t i v e species i n t h i s m e d i m e A s t a b l e r e f e r e n c e p o t e n t i a l will also be needed f o r measurements of t h e potential of a s p e c i f i c f l u o r i d e i o n electr~de (Subtask 5.1.2.5) and for an o x i d e e l e c t r o d e (Subtask 5.1.2.8). The electrode may a l s o b e used t o measure the c o n c e n t r a t i o n of c e r t a i n elect r ~ a c t i v es p e c i e s i n t h e m e l t o r i n bismuth and to i n d i c a t e d i v e r g e n c e from e q u i l i b r a t i o n between t h e s a l t and bismuth a l l o y . The two most cornonly used r e f e r e n c e e l e c t r o d e s in m l t e n c h l o r i d e are based on the silver-silver chloride and the platinum &IE)-glatinum c o u p l e s . Electrodes based on t h e s e couples will be tested i n synthetic m e l t s a t p r o c e s s suitable f o r i n - l i n e measurements w i l l b e t e ~ ~ ~ p e ~ a t u rEPect~odles es. developed and t e s t e d f o r v a r i o u s p o t e n t i o m e t r i c a p p l i c a t i o n s .

6.4.6.7

Subtask 5.1.2.7

D e t e r ~ a a t i o nof total corrosion p r o d u c t s

&. ,

*.... ,<..:

k.,

6-35 p o s s e s s s o l u b l e sub-zero o x i d a t i o n s t a t e s , most c o r r o s i o n p r o d u c t s w i l l n o t b e d i r e c t l y measurable by the e l e c t r o a n a l y t i c a l methods. In-line e l e c t r o l y t i c methods w i l l b e t e s t e d f o r t h e q u a n t i t a t i v e conversion of c o r r o s i o n p r o d u c t s t o s o l u b l e i o n i c s p e c i e s . Chemical methods such as t r a n s p i r a t i o n w i t h E161 o r c h l o r i n e w i l l a l s o b e t e s t e d under Task Group 5.3. The most s u c c e s s f u l o x i d a t i o n method w i l l be combined with e l e c t r o a n a l y t i c a l methods t o p r o v i d e a d e v i c e f o r t h e i n - l i n e measurement of t h e t o t a l c o n c e n t r a t i o n s of i n d i v i d u a l c o r r o s i o n p r o d u c t s .

6.4.6.8

Subtask 5.1.2.8

Determination of oxide

The r o l e of o x i d e i n t h e m e t a l t r a n s f e r p r o c e s s i s mot y e t thoroughly understood. Qxide l a y e r s are b e l i e v e d t o have decreased t h e rate of t r a n s f e r of materials between bismuth and s a l t i n e n g i n e e r i n g e x p e r i ~ ~ n t s , and s i g n i f i c a n t o x i d e could i n c r e a s e t h e c o r r o s i v i t y of l i t h i u m c h l o r i d e and a f f e c t t h e d i s t r i b u t i o n c o e f f i c i e n t s of c e r t a i n metals between t h e s a l t and metal phases. It t h e r e f o r e a p p e a r s l i k e l y t h a t i t w i l l be n e c e s s a r y t o monitor and c o n t r o l o x i d e c o n c e n t r a t i o n i n t h e l i t h i u m c h l o r i d e streams and a n i n - l i n e method f o r t h e d e t e r m i n a t i o n of o x i d e s would assist such c ~ n t r o l . Prom thermodynamic c o n s i d e r a t i o n s i t a p p e a r s u n l i k e l y that a v o l t a m e t r i c wave f o r mcomplexed o x i d e s will be availa b l e w i t h i n t h e working l i d t s of l i t h i u m c h l o r i d e m e l t s . T h i s assumpt i o n w i l l , of c o u r s e , b e checked e x p e r i m e n t a l l y and a s e a r c h f o r waves of o x i d e complexes such as o x i a n i o n s will be made. It i s l i k e l y , t h e r e f o r e , t h a t p o t e n t i o m e t r i c measurements w i l l o f f e r t h e most f r u i t f u l approach. Because i t a p p e a r s t h a t ceramie materials will b e less s u b j e c t t o a t t a c k i n t h i s medium than i n t h e molten f l u o r i d e s , t h e development of more c o n v e n t i o n a l e l e c t r o c h e m i c a l c e l l s should b e p o s s i b l e . Approaches ~ L l iln c l u d e t h e u s e of selective ceramic membranes and t h e development of c a p i l l a r y o r porous ceramic s a l t b r i d g e s between e l e c t r s c h e m k a l half cells. Zirconia doped w i t h calcium becomes an i o n i c conductor at high temperatures by v i r t u e of mobile o x i d e i s m s and w i l l be t e s t e d f o r a p p l i c a t i o n t o a s p e c i f i c oxide electrode. Electrode couples reported t o behave r e v e r s i b l y w i t h r e s p e c t t o o x i d e i o n i n molten L i C l - K C 1 i n c l u d e Cu/Cu20, €%/ago, Pd/PdO and B i / B i O C l .

The behaviour o f t h e s e c o u p l e s will be i n v e s t i g a t e d i n p u r e E i C l m e l t s . The moat f a v o r a b l e o f t h e s e c o u p l e s and t h e most p r a c t i c a l means of developing ionic c o n t a c t with t h e l i t h i u m c h l o r i d e m e l t s w 5 l l be used t o d e s i g n a n e l e c t r o d e i n accordance w i t h t h e u s u a l requirements of u n i t c o n s t r u c t i o n f o r i n - l i n e a p p l i c a t i o n . Models of t h i s e l e c t r o d e w i l l b e e v a l u a t e d f o r parameters such as N e r n s t i a n r e s p o n s e , response t i m e , limits of d e t e c t i o n , and r e p r o d u c i b i l i t y of p o t e n t i a l measurements. Whem a s a t i s f a c t o r y e l e c t r o d e a p p e a r s t o have been developed it w i l l be s u b j e c t e d t o l o n g t e r m exposures i n r e s e a r c h m e l t s o r i n - l i n e a p p l i c a t i o n t o e s t a b l i s h i t s r e l i a b i l i t y and u s e f u l l i f e t i m e .

6-36 .w.s ..(..

6.4.7

Task 5.1.3

Coolant s a l t a n a l y s i s

Cu~rently, a l a r g e f r a c t i o n of the e l e c t r o a n a l y t i c a l r e s e a r c h and develspment effort i s b e i n g devoted t o a p p l i c a t i o n s i n t h e proposed e u t e c t i c coolawt, NaBP,--NaP (92-8 mole These studies are p r i m r i l y concerned With t h e deVebpmE5tt of lE?thOds f o r the in- line lWaSUE%l~ntOf CQrrosiOn product ions and p r o t o n i c s p e c i e s and with t h e e s t a b l i s h m e n t of the n a t u r e and p r o p e r t i e s of p r o t o n a t e d s p e c i e s i n t h e molten c s o l a n t . The measurement and c o n t r o l ~f p r o t o n a t e d s p e c i e s i n the c o o l a n t i s of p a r t i c u l a r i n t e r e s t because of t h e p o t e n t i a l use u f t h e coolant f o r t h e containment of tritium. S t u d i e s o f p r o t o n a t e d species are of high p r i o r i t y because operation of t h e Coolant-Salt Technology Facility (CSTP) - the first m-jor facility to b e equipped w i t h il s u i t a b l e s y s t e m for i n - l i n e e l e c t r o a ~ ~ a P y t F ~ a lI I E ~ S U ~ ~ I I E R ~-S is about to be ~ e s ~ m e d .One of t h e first e ~ p e r i leseX2t.S With t h i s facility, t h e H)@UteKiUfn InjaSCtiCX? E q a S K i t W X l t , 6 2 iS ned t o p r o v i d e d e f i n i t i v e data on t h e e f f e c t i v e n e s s of fluorsborate f o r the containment sf t ~ i t i t~ h a~ t w~i il l be generated in t h e reactor f u e l salt. I n - l i n e measurements w i l l be needed to deternine the d i s t r i b u t i o n of deuterium which will be used as a s t a n d - i n for t r i t i u m . rials c o m p a t i b i l i t y s t u d i e s will a l s o be performed i n % h i s f a c i l i t y , probably concurrent%y w i t h t h e deuterium experiments. I n - l i n e s u p p o r t of t h e s e a c t i v i t i e s will. be provided by t h e e l e c t r o a n a l y t i c a l measurement of C O K P O S ~ O product ~ i o n s . Research and development s t u d i e s wLlE a l s o be carried o u t i n a l t e r n a t e c o o l a n t compositions t h a t may be s e l e c t e d l a t e r . Many of t h e c a n d i d a t e c o o l a n t s a l t s are expected t o have similar properties to the mm fuel Solvent fn Which eXt@nSiVe e l e c t P o a n d y t i C a l s t u d i e s have a l r e a d y been made. Unless a really novel c o ~ ~ p o s i t i oi ns s e l e c t e d as an a l t e r n a t e coolant, t h e r e q u i r e d development s t u d i e s ~511 be l i m i t e d t o t h e measurement of e s s e n t i a l c o n s t a n t s suck as d i f f u s i o n c o e f f i c i e n t s , and t h e c h a r a c t e r i z a t i o n sf new c o n s t i t u e n t s t h a t m y be i n c o r p o r a t e d i n t o container materials. T h e r e f o r e , no d e t a i l s f o r s t u d i e s i n alternate c o o l a n t s w i l l b e p r o j e c t e d f o r these s u b t a s k s .

,%>.

6.4.7.1

Subtask 5.1.2.1

Determination of i o n i c c o r r o s i o n p r o d u c t s

&..

6-37 level) for i r o n and chromiun i o n s , and f o r a newly discovered wave t h a t probably c o ~ ~ e s p o n dt o s the r e d u c t i o n of MS3+* The measurement sf n i c k e l w a s f ~ ~ tno dbe impractical. because sf t h e low s o l u b i l i t y of NIP2 i n f l u o r o b o r a t e s . Although each of t h e waves i s d i s t i n c t l y o b s e r v a b l e , q u a n t i t a t i v e i n t e r p r e t a t i o n of t h e waves from t h i s multicomponent mixture of ions i s d i f f i c u l t because early (more c a t h o d i c ) waves c o n t r i b u t e a significant b u t i n d e t e r m i n a t e c u r r e n t a t t h e peak p o t e n t i a l of the suec e d i n g wave. F u r t h e r measurements of i n d i v i d u a l i o n s and combinations of i o n s w i l l be performed i n researefn m e l t s to obtain d a t a f o r q u a n t i t a t i v e i n t e r p r e t a t i o n of voltammogram. Pulsed voltammetry and compute^ methodsG3 FJill b e t e s t e d f o r improving r e s o l u t i o n of a d j a c e n t waves. Ink i n e measurements will be performed throughout t h e o p e r a t i o n of t h e CSTF to d e t e c t relative changes i n t h e c ~ n c e n t r a t i o n sof c o r r o s i o n p r o d u c t s e t h a t can be t h a t r e s u l t from v a r i o u s experiments and t o p ~ o ~ i ddata i n t e r p r e t e d more q u a n t i t a t i v e l y a f t e r a d d i t i o n a l development work i s completed. 6.4.7.2

Subtask 5.1.3.2

D e t e r d n a t i o n s f p r o t o n a t e d species

BeCauSe of t h e p o t e n t i a l Value O f t h e cQOh2t f o r t h e Conta$~iIlent Of t K i t i U l l l , the XXeaSUPe~ent Of pKOtOblated §p@Cies iIl. t h e P-itQgOSed COShnt s a l t is of primary Pnportance. The monitoring of p r o t a n a t e $ species could a l s o provide i n f o r m t i o n on corrosiom rates as a f u ~ ~ c t i oof n the c o n c e n t r a t i o n o f p r o t o n a t e d s p e c i e s and serve as a p o s s i b l e d e t e c t i o n t e c h n i q u e f o r steam g e n e r a t o r Peaks. Ve w i l l c o n t i n u e i n v e s t i g a t i n g a unique e l e c t r o a n a l y t i c a l t e c h n i q u e t h a t i s s p e c i f i c f o r hydrogen. The method i s based on the d i f f u s i o n of hydrogen i n t o a n evacuated p a l l a d i m t u b e e l e c t r o d e when the coolant salt i s e l e c t r o l y z e d at a c o n t r o l l e d p o t e n t i a l . Both t h e amplitude of v o l t a m e t r i c waves ~ e c ~ r d ea dt t h e p a l l a d i a e l e c t o d e and the rate of i n c r e a s e of hydrogen p r e s s u r e d t h i n the e l e ~ t ~ o dare e p r o p o ~ t i o n a lt o t h e c o n c e n t r a t i o n of an active protOnated Species, pKObab8y HI?;! in f f U Q r Q b 0 r a t eXlldtS. The preSsUKe measureaent p r o v i d e s t h e g r e a t e s t s e n s i t i v i t y . Standard a d d i t i o n s t o the 500 K g o f NaBP4-NaF c o o l a n t i n the CSTF have demonstrated t h a t active p r o t o n c o n c e n t r a t i o n s of a few p a r t s per b i l l i o n w i l l produce a measurable p r e s s u r e rise on e l e ~ t r o l y s i s . An e l e c t r o d e of even b e t t e r s e n s i t i v i t y w i l l be needed t o support deuterium i n j e c t i o n s t u d i e s .

The s e n s i t i v i t y of the active p r o t o n ~ ~ ~ i s u ~ ewmi lnl tbe i n c r e a s e d at least t e n f o l d by using an electrode of larger area t h a t i s coupabed ~ 5 t h an improved vacuum system and a more s e n s i t i v e p r e s s u r e measuring d e v i c e . This i ~ ~ ~ p ~ osystem v e d w i l l be c a l i b r a t e d a t t h e CSTP by s t a n d a r d a d d i t i o n t e c h n i q u e s ( s t a n d a r d a d d i t i o n s a t t h e s e %ow concentration levels are not p r a c t i c a l ~ O Ksmall r e s e a r c h m e l t s ) and used i n s u p p o r t of e x p e r i ments i n which deuterium w i l l b e d i f f u s e d into the c o o l a n t . The vacuum System for t h e e l e c t r o d e be designed i n aCCQKdEiW3.2d t h gas sampling requirements f o r Subtask 5 . 1 . 3 . 3 .

6-38

6.4.7.3

Subtask 5 . 1 . 3 . 3

Determination of hydrogen apld i t s i s o t o p e s

I n o r d e r t o evaluate deuterium i n j e c t i o n experiments a t t h e C S T F ~ ' i t w i l l be n e c e s s a r y t o d i s t i n g u i s h between active protons and a c t i v e deuterons i n the m e l t . S i m i l a r l y , t h e measurement of t r i t o n s will be required f o r later t r i t i u m i n j e c t i o n experiments and f o r a p p l i c a t i o n t o a c t u a l r e a c t o r c o o l a n t s . I m c o n j u n c t i o n w i t h Subtask 5 . 1 . 3 . 2 (Determination of p r o t o n a t e d s p e c i e s ) , t h e palladium t u b e e l e c t r o l y s i s techn i q u e dll b e extended t o t h e d e t e r m i n a t i o n of i s o t o p i c forms of hydrogem. This w i l l b e accomplished by a p p l y i n g c o u n t i n g and m a s s s p e c t r o g r a p h i c methods t o samples c o l l e c t e d i n t h e evacuated p a l l a d i u m e l e c t r o d e . This approach o f f e r s t h e advantage of s p e c i f i c i t y m d a p p l i c a b i l i t y t o inl i n e monitoring. When an i n - l i n e mass s p e c t r o m e t e r becomes a v a i l a b l e , it w i l l b e t e s t e d i n c o n j u n c t i o n w i t h an improved palladium e l e c t r o d e as a means f o r p r o v i d i n g real t i m e d a t a f o r i s o t o p i c hydrogen measurements. Also, methods f o r t h e i n - l i n e neasurement of t r i t i u m by i m t e r n a l gas p r o p o r t i o n a l c o u n t i n g i n flow-through c e l l s w i l l be s t u d i e d , A f u r t h e r e x t e n s i o n of t h e a p p l i c a t i o n of t h e palladium e l e c t r o d e will be t o measure e l e m e n t a l hydrogen and i t s i s o t o p e s t h a t are i n s o l u t i o n i n t h e c o o l a n t . This can, i n t h e o r y , be accomplished by m e a s u r h g t h e hydrogen that d i f f u s e s i n t o a n e l e c t r i c a l l y i s o l a t e d palladium e l e c t r o d e . The c a p a b i l i t i e s and l i m i t a t i o n s of t h i s approach will b e e s t a b l i s h e d i n r e s e a r c h m e l t s t h a t are s u b j e c t e d to a n over-pressure of hydrogen. I f adequate s e n s i t i v i t y can be o b t a i n e d , t h i s method w i l l be used t o measure t h e rat50 of f r e e and CB i n e d hydrogen and i t s i s o t o p e s d u r i n g i n j e c t i o n experiments a t the CSTF. A predominant f r a c t i o n of t h e p r o t o n c o n t e n t of t h e f l u o r o b o r a t e coolant s a l t w i l l be p r e s e n t as BF$3.-I-, a s t a b l e s p e c i e s t h a t does n o t reduce a t t h e palladium e l e c t r o d e . I t s p o t e n t i a l r o l e i n t h e containment of tritium is n o t thoroughly e s t a b l i s h e d . Spectrophotometric e v i d e n c e h a s shown t h a t its p r o t o n does n o t r e a d i l y exchange w i t h deutereiun t h a t i s d i f f u s e d i n t o molten f k u o r s b o r a t e b u t t h a t B P ~ O D - is g e n e r a t e d by sxidation ~eactions. It has been suggested t h a t t h i s s p e c i e s could b e used t o r e t a i n a major f r a c t i o n of the t r i t i u m t h a t d i f f u s e s i n t o the c o o l a n t system.64 A t p r e s e n t t h e only e s t a b l i s h e d method f o r t h e measurement of B P ~ O H - i n v o l v e s t h e measurement .DE i t s i n f r a r e d a b s o r p t i o n a t 3641 cm-1, u s u a l l y i n a p e l l e t p r e s s e d from pulverized samples. T h i s i s a l e n g t h y e m p i r i c a l procedure and an -i n s i t u o r i n - l i n e method would c o n t r i b u t e g r e a t l y t o t h e r e s e a r c h and development s t u d i e s on t r i t i u m containment. Anodic voltammetry will b e i n v e s t i g a t e d as a method f o r t h e d e t e r m i n a t i o n of BF30H-. A wave recorded on gold e l e c t r o d e s has been observed t o v a r y i n p r o p o r t i o n t o t h e BF30H- c o n c e n t r a t i o n . T h i s wave w i l l be fully chara c t e r i z e d and used t o develop a method f o r measurements i n t h e CSTF.

6,4,7,hC

Subtask 5.1.3.4

I n ~ e s t i g a t i o nof redox-buffer

couples

~n t h e reactor fuel, t h e U ~ - B - / U ~ * couple p ~ o ~ a i d ectmnica.~. s i n e r t i a that will p r e v e n t g r a s s changes in K ~ ~ Qp oXt e n t i a l from moderate a d d i t i o n s of o x i d a n t s o r r e d u c t a n t s .

To Q U ~knowledge no b u f f e r of a d e q u a t e

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6-39

....

.... .... ,*%

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c a p a c i t y is i n h e r e n t l y p r e s e n t i n t h e f l u o r o b o r a t e c o o l a n t . The i n c o r p o r a t i o n of a s u i t a b l e redox b u f f e r i n t o t h i s o r a l t e r n a t e c o o l a n t s would make i t p o s s i b l e t o a c h i e v e b e t t e r c o n t r o l of c o r r o s i v i t y and, perhaps, more e f f e c t i v e containment of t r i t i u m . V o l t a m e t r i c methods provide a v e r y e f f e c t i v e means f o r s c r e e n i n g c a n d i d a t e redox couples by determining such p r o p e r t i e s as s t a n d a r d p o t e n t i a l s amd r e v e r s i b i l i t y . V o l t a m e t r i c s t u d i e s w i l l b e used t o c h a r a c t e r i z e suggested redox couples f o r t h e and ~ i 4 * / ~ i 3 + , ~t should a l s o be noted t h a t c o o l a n t , such as ~ e 4 + / ~ e 3 + t h e i n c o r p o r a t i o n of a redox couple w i l l permit a convenient measurement of t h e redox p o t e n t i a l of t h e c o o l a n t . 6.4.7.5

Subtask 5.1.3.5

Development of r e f e r e n c e e l e c t r o d e s

In e l e c t r o a n a l y t i c a l measurements i t i s a d i s t i n c t advantage t o have an i n v a r i a n t r e f e r e n c e p o t e n t i a l t o which t h e p o t e n t i a l of o t h e r e l e c t r o chemical r e a c t i o n s may b e r e f e r r e d on a r e l a t i v e p o t e n t i a l scale. The requirements f o r a r e f e r e n c e e l e c t r o d e and problems a s s o c i a t e d w i t h t h e i r a p p l i c a t i o n s t o molten f l u o r i d e s y s t e m are d i s c u s s e d i n Subtask 5.1.1.15. Reference electrodes are sf even more importance i n coolant s a l t s y s t e m t h a n i n f u e l s y s t e m , because a t p r e s e n t no s u i t a b l e r e v e r s i b l e couple is a v a i l a b l e t o serve as a p o t e n t i a l marker. Moderate s u c c e s s h a s been r e a l i z e d w i t h an Pe/PeFZ r e f e r e n c e e l e c t r o d e i n which t h e r e f e r e n c e s o l u t i o n ( c o o l a ~ ts a l t s a t u r a t e d w i t h PeP2) i s c o n t a i n e d i n a simgle c r y s t a l of lanthanum t r i f l u o r i d e . N e r n s t i a n r e s p o n s e w a s o b t a i n e d €or t h i s e l e c t r o d e f o r Em measurements on i r o n ( P I ) / i r o n c o n ~ e n t r a t i o nc e l l s . However, o c c a s i o n a l c r a c k i n g of t h e LaF3 c r y s t a l s w a s encountered. Cons e q u e n t l y , f u t h e r e f f o r t s will b e made t o develop more rugged i o n i c cond u c t o r s . A p r a c t i c a l referemce e b e c t r o d e should b e of u n i t c o n s t r u c t i o n and s u f f i c i e n t l y rugged t o f u n c t i o n f o r i n - l i n e s i t u a t i o n s over extended The p r e s e n t model r e f e r e n c e e l e c t r o d e and any f u t u r e p e r i o d s of t i m e . ~ I T I ~ K Q aVs s~ e m b l i e s w i l l b e used i n t h e c o o l a n t i n t h e CSTP t o o b t a i n p r a c t i c a l experience. 6.4.7.6

Subtask 5.1.3.6

Determination of t o t a l c o r r o s i o n p r o d u c t s

C o n t r o l l e d - p o t e n t i a l v o l t a m e t r y (Subtask 5.1.3.1) p r o v i d e s a measurement of ORPY t h e s o l u b l e i o n i c c o r r o s i o n p r o d u c t s . Corrosion p r o d u c t s m y a l s o be p r e s e n t as f i n e l y d i v i d e d metals o r as o t h e r i n s o l u b l e forms. A more meaningful measurement of t h e cumulative c o r r o s i o n of t h e c o o l a n t system would i n c l u d e t h e c o n c e n t r a t i o n of t h e s e non-ionic s p e c i e s . Methods w i l l b e developed f o r t h e i n - l i n e conversion of t h e t o t a l corr o s i o n product c o n t e n t of c o o l a n t s a l t t o s o l u b l e i o n i c s p e c i e s f o r e l e c t r o a n a l y t i c a l measurement. Both e l e c t r o l y t i c and t r a n s p i r a t i o n a l o x i d a t i o n procedures w i l l be t e s t e d . The f i r s t such test w i l l probably be made on i s o l a t e d test p o r t i o n s o f t h e c o o l a n t m e l t i n t h e CSTF.

6-48 6.4.9.7

Subtask 5.1.3.7

Determination of oxygenated s p e c i e s

A d d i t i o n a l i n f o r m a t i o n i s needed on t h e behavior of oxygenated s p e c i e s i n f l u o m b o r a t e m e l t s . For example, the s o l u b i l i t y of Na2B2P60 in t h e c o o l a n t salt i s not V ~ K Ywe11 known and an u n d e r s t a n d i n g of t h e e q u i l i b r i a among the v a r i o u s oxygenated s p e c i e s and t h e f l u o m b o r a t e C Q Q ~ ~ Kalso L ~ awaits f u r t h e r s t u d y . E l e c t r o a n a l y t i c a l methods will be used t o charact e r i z e and measure t h e electroactive oxygenated compomds. E f f o r t s will a l s o be made t o develop a n oxide i o n s p e c i f i c e l e c t ~ o c l ewhereby t h e o x i d e i o n a c t i v i t y could b e determined f r o m p o t e n t i o m e t r i c measurements.

6.4.8

Task 5 . 1 . 4

E f f e c t s o f r a d i a t i o n on e l e c t r o a n a l y t i c a l t r a n s d u c e r s

E l e c t r o a n a l y t i c a P t r a n s d u c e r s w i l l i n g e n e r a l be s u b j e c t e d t o i n t e n s e beta and gamma r a d i a t i o n . Unless experiments t o perform measurements d t h i r t the core of an experimental r e a c t o r are implemented, exposure t o n e u t r o n s w i l l b e l i m i t e d to l e a k a g e and delayed n e u t r o n s and m y be negl i g i b l e a t many l o c a t i o n s . The e f f e c t s ~f h i g h b e t a and ga levels w i l l be s t u d i e d t o a s s u r e t h a t i n - l i n e i n s t r u m e n t a t i o n will funct i o n p r o p e r l y i n t h e u l t i m a t e a p p l i c a t i o n . Earlier work has a f f o r d e d OHlly limited O p p O % t U l l i t ~ e St0 te§t e ~ e C t P O a n E l l y t i C E l lIDC?thQdS b r a d i a t i o n eHlrPirolnmentS & a S U ~ @ I W I l t § of t h e u3+/u4+ Katio a sample Of f u e l W i t h d l r a % 6 E n from the mmI5 tend to s u p p o r t t h e f e a s i b i l i t y s f such measurements in r a d i o a c t i v e environments. However, because s f t h e neee s s a r y d e l a y s i n t r a n s f e r o f t h e sample t o a hot c e l l a p p a r a t u s the a c t i v i t y of the sample had decayed by more t h a n an o r d e r of magnitude. A l s o , the e ~ p ~ s u was, re p e r f o r c e , of b r i e f d u r a t i o n . E t w i l l t h e r e f ~ r e be n e c e s s a r y t o p r e d i c t areas of p o t e n t i a l d e t r i m e n t a l effect i n o r d e r t o design r e a l i s t i c ~ X ~ O S U e~pepriments K ~ t h a t w i l l e s t a b l i s h the magnitude of t h e s e e f f e c t s . T e n t a t i v e l y , t h e o r d e r sf i n c r e a s i n g p r o b a b i l i t y of r a d i a t i o n e f f e c t s w a d d b e damage to insulating materials f o r t h e penet r a t i o n of electrode l e a d s i n t o t h e r e a c t o r system, damage t o t h e n o b l e metal e l e c t r o d e s themselves, damage t o i n s u l a t i n g materials t h a t are exposed ts the molten s a l t stream, and t h e e f f e c t s an c o u p l e s needed for p o t e n t i o m e t r i c IIE~SUK~IEII~S. S e p a r a t e p ~ o g r a mof ~ experimental e r n p ~ s ~ rwei 1 1 b e r e q u i r e d in each of t h e s e areas.

k..

>.:b

P e n e t r a t i o n i n s u l a t o r s which are s t a b l e t o radiation w i l l be developed Fn o t h e r phases of t h e MSBR Program OK i n o t h e r r e a c t o r programs. The onlby need w i l l b e t o select from such s t u d i e s materials t h a t will be compatible with the cover gas of t h e a p p r o p r i a t e s a l t system and perhaps pe]rfo?Xl %hd.ted eX&9@KiPJentsto Verify their pekfOlXElnCe ill this application. It i s not expected t h a t t h e noble metals w i l l receive s u f f i c i e n t radiat i o n e ~ p s t u r et o cause unacceptable m o d i f i c a t i o n s of their s t r u c t u r a l p r o p e r t i e s s i n c e l i t t l e stress i s a n t i c i p a t e d . Surface p r o p e r t i e s of v o l t a m e t r i c @lectKOdeS can e x e r t a s i g n i f i c a n t e f f e c t on t h e i r response t h a t i s n o t y e t fully understood. FQK example, t h e o p e r a t i o n of eleetrsdes beyond melt EHlits for even b r i e f p e r i o d s can d i s t o r t the shape

.... e=.

h,.

6-41 of v o l t a ~ ~ ~ ~ ~waves. e t r i c I n g e n e r a l , t h e damage from such e x c u r s i o n s ts heals'l r a p i d l y d u r i n g normal o p e r a t i o n of t h e e l e c t r o d e s . The csntinuous exposrere of e l e c t r o d e s u r f a c e s t o b e t a r a d i a t i o n could p r o v i d e a cOntiIlUOu% S u r f a c e d2UTEige t h a t Would i n t r o d u c e e K r O P S i f its e f f e c t iS n o t p r e d i c t a b l e . The e f f e c t s could, s f C O V K S ~ , be benign i n some cases, b u t must be s t u d i e d b e f o r e t h e a p p l i c a t i o n of e l e c t r ~ a n a l y t i c a methods l t o a c t u a l r e a c t o r streams. 891 e ~ p e ~ i m e n t aprogram l w i l l be designed to determine t h e effeccs of r a d i a t i o n on v a r i o u s e l e c t r o d e ~ ~ t t e ~ iand als t o select t h o s e materials Beast s u b j e c t t o damage. Because of t h e t r a n s i t o r y n a t u r e of such phenomena i t w % l l u l t i m a t e l y be necessary t o perform exposure tests during measurements i n molten s a l t s . Due t o the eXpe%lSe Sf such e ~ e K i ? W ~ t . SScreening , t e s t s &%% first be perfoa6IBd f o r v a r i o u s c a n d i d a t e e l e c t r o d e materials by exposing e l e c t r o d e s i n a v a i h b l e material test f a c i l i t i e s , and t h e n comparing t h e response of t h e exposed e l e c t r o d e s with those of v i r g i n e l e c t r o d e s . Such tests m y eliminate c e r t a i n materials from f u r t h e r c o n s i d e r a t i o n . The remining materials w i l l then b e tested under e o ~ ~ d i t of i ~ i~ n c~r esa s i n g s e v e r i t y ~f exposure. The first s a l t test w i l l b e pek-formed i n melts t o which ~ ~ ~ d i a t ei noenr g y i s added as htgh-energy a l p h a emitters. These tests w i l l n o t b e r e a l i s t i c but can be performed w i t h i n convenient alpha e n c l o s u r e s . Subsequent tests on materials t h a t suk-vive t h e a l p h a expoSure Will be perfok-med with t h e a d d i t i o n o f s h o r t - l i v e d %setae ~ t t e r si n h o t c e l l s . Proper f u n c t i o n i n g d u r i n g t h e s e exposures should be s u f f i c i e n t $8 e s t a b l i s h the a p p l i c a b i l i t y t o reactor systems. Measurements under i n - p i l e ~ o n d i t i ~ will ~ s s be made i f p o s s i b l e .

....

N & !

... ...

An i n s u l a t i n g material which can s i m u l t a n e o u s l y w i t h s t a n d exposure t o salt and r a d i a t i o n would g r e a t l y assist the V o l t a m e t r i c ~ ~ ~ @ a s u r e ~ ~ ~ n % s . It is not e s s e ~ ~ t i ahowever, l, because, with V C J ~ ~ Z U T L I Xs If ~ higher ~~~S CUPr e n t c a p a b i l i t i e s and e l e c t r o d e s of a p p r o p r i a t e g e o m e t r i c a l d e s i g n s , adequate definition of e l e c t r o d e areas can probably be achieved w i t h o u t insulators. A compatible i n s u l a t i n g material w i l l b e r e q u i r e d f o r the development of r e f e r e n c e e l e c t r o d e s , ~ o T + J wa~program ~, similar t o t h a t suggested f o r t h e s t u d y of r a d i a t i o n e f f e c t s on e l e c t r o d e materials w i l l b e used f o r t h e in-stream i n s u l a t i n g materials. Work i s now in p r o g r e s s t o d i s c o v e r i n s u l a t i n g materials of s u p e r i o r c o m p a t i b i l i t y w i t h non-radioactive molten salts. Those materials that prove s u i t a b l e f o r % h i s a p p l i c a t i o n w i l l be screened by f a i r l y simple r a d i a t i o n exposure tests t h a t w i l l d e t e c t d e t e r i o r a t i o n of i n s u l a t i n g p r o p e r t i e s ~ n d e k -t h e i n f l u e n c e sf approprate r a d i a t i o n a t t h e temperature of t h e r e a c t o r stream. Materials showing promise w i l l i n t u r n b e s u b j e c t e d t o more strehausus tests t o determine whether d e g r a d a t i o n w i l l o c c u r in molten s a l t s t o which r a d i o a c t i v e i s o t o p e s have been added. These tests w i 1 1 b e designed t o determine whether an i n c r e a s e d rate of d i ~ ~ o l u t i 0 ~1rn attack w i l l occur as a r e s u l t of t h e a b s ~ r p t i o nof r a d i a t i o n energy. to~ select c a n d i d a t e s f o r the fabrication of f i n a l These tests w i l l S ~ K V models of reference and s p e c ~ f i c - i o n electrodes f o r even mre lgigorgaus testing

6-42 R@f@Pence e l e c t r o d e s which i n v o l v e ii c h e d c d couple f Q r p o t e n t i a l measurements are p o s s i b l y t h e m o s t v d n e r a b l e t o r a d i a t i o n e f f e c t s . In a d d i t i o n t o t h e materials problem t h a t are d e s c r i b e d above, t h e i n t r s d u c t i s n of r a d i a n t energy a t t h e s e levels way be s u f f i c i e n t t o a f f e c t t ~ yt h e ~ e f e r e n c ec o u p l e s . Normally one would expect the t h e c h e ~ ~ i s of r a d i a t i o n exposure t o merely a s s u r e more r a p i d a t t a i n m e n t of e q u i l i b r i u m p o t e n t i a l s ; however, at t h e a n t i c i p a t e d r a d i a t i o n levels a s t e a d y s t a t e c o n d i t i o n t h a t d e v i a t e s from e q u i l i b r i u m p r e d i c t i o n s could b e generated. b d e E s of t h e s e e l e c t r o d e s ~Lll be s u b j e c t e d on a g r a d i e n t scale t o condit i o n s t h a t u l t i m a t e l y approach o r exceed t h o s e expected i n r e a c t o r a p p l i c a t i o n s . This w i l l i n c l u d e e i t h e r i n - p i l e t e s t i n g i n molten f u e l s OK l . ~ s u b j e c t e d t o appromeasurements in f u e l s t h a t have quite ~ e c e n ~been p r i a t e Bevels of n e u t r o n i r r a d i a t i o n . Whe~evea:p o s s i b l e t h e s e r a d i a t i o n - e f f e c t s t u d i e s w i l l be performed i n c o n j u n c t i o n w i t h o t h e r i n - p i l e experiments t h a t m y be c a r r i e d o u t by t h e Program, which w i l l permit more economical t e s t i n g and provide more r e a l i s t i c environments. 6.5

TASK GROW 5.2

6.5.1

Objective

APPLICATION OF SPECTROPHOTOMETRIC FETNODS

The o b j e c t i v e 05 Task Group 5.2 2s t o develop s p ~ ~ t r o p h o t o m e t r methods ic t h a t will be useful for the a n a l y s i s of f u e l , c o o l a n t , and p r o c e s s i n g streams of t e s t , d e ~ i - ~ n s t r a t i o nand , p o w e ~P ~ ~ C ~ Q P and S , to aid i n the e v a l u a t i o n of t h e chemistry of such streams. The s t u d i e s w i l l b e c a r r i e d o u t on a schedule t h a t will permit t h e u s e of such methods i n s u p p o r t of r e s e a r c h and t e c h n o l o g i c a l s t u d i e s of t h e MSBR development program. Spectral s t u d i e s have been used t o h e l p e s t a b l i s h t h e u s e f u l n e s s of the voS_tametrie uranium method, t o a i d i n t h e i d e n t i f i c a t i o n of chemical s p e c i e s i n molten f l u o r i d e salts, and to e s t a b l i s h t h e nature of e s r r o s i o n SQEut@Species. Such s t u d i e s , to d a t e , have been on a batch-wise b a s i s w i t h only exploratory c o n s i d e r a t i o n of i n - l i n e a n a l y s i s . The advent of t u n a b l e lasers, t h e development s f s u i t a b l e slotted o p t i c a l p r o b e s , and t h e a v a i l a b i l i t y of e x p e r i m e n t a l s a l t l o o p s , w i l l accelerate t h e development of methods f o r i n - l i n e s p e c t r a l analysis.

6.5.2

Schedule

The s c h e d u l e for work in t h e task group i s shorn i n Table 6.5.2.

6.5.3

Funding

Operating fund r e q u i ~ e m n t sfor t h i s t a s k group are shorn i n Table 6.5.3.1, and c a p i t a l equipment faand ~ e q ~ i r e ~ are ~ ~ shown n t s i n Table 6.5.3.2.

Table 6.5.2.

Schedule

for work in Task Group 5.2 -Application

1975 5.2.1

5.2.2

5.2.3

5.2.4

Fuel salt analyses 5.2.1.1 u3+ 5.2.1.2 Total uranfum 5.2.1.3 Plutonium 5.2.1.4 Protactinium 5.2.1.5 US+ 5.2.1.6 Oxygenated species 5.2.1.7 Turbidity 5.2.1.8 Tellurium 5.2.1.9 Diamond-tipped optical probe LiCl analyses 5.2.2.1. Uranium 5.2.2.2 Plutonium 5.2.2.3 Oxide 5.2.2.4 Hydroxide 5.2.2.5 Transition metal 5.2.2.6 Sapphire opthal Coolant 5.2.3.1 5.2.3.2 5.2.3.3 5.2.3.4 5.2.3.5 5.2.3.6

salt analyses BF30H- and BF$DOxide Protanated species Corrosion product ions Redox buffers Optical probe

--_-_-. -

Effects of radiation on optical components and spectra

methods

1986

1976

ions probe

of spectraphotometric

5.2.1

Fusl salt amaiyses 5.2.1.1 IF5.2.1.2

Tat221

uranium

5.2.P.3

Plutanium

5.2.P.4 5.2.1.5 5.2.1.6 5.2.1.7 5.2.1.8

PKQtactimbml -us+ Oxygemated Turbidity aeaaurim

5,2.1.9

Dimond-tipped

3 2

5 5

5 3 3

species 2

3 -.28

5.2.3

LBCl analyses 5.2.2.1 UPanium 5.2.2.2 PPutoniu0l 5.2.2.3 Qxide 5.2.2.4 HydKQxide 5.2.2.5 Transftiom 5.2-2.6 Sapphire

metal optical

Subtotal

5.2.2

Coolant 5.2.3.1 5.2.3.2 5.2.3.3 5.2.3*4

salt analyses BF30H- and BF$DOxide Protonated species Carrosisn

5 8 8 7

10 10 10

3 5

5 5

7 5

10 BQ

5 35

5 43

7 49

.10

2 2

4 4 4

optfcal

probe

5.2.2

5 6 6 5

pmduct

ions probe

3 3 3

7 5

8 5

12 5

PQ 2 ions

1Q BQ 10 10 4Q

15 15

4 2

10 IQ 6 6 5 37

“5 5

3 4 3 3

:::: u::

Table 6.5.3.1

1975

5.2.4

5.2.3.5 5.2.3.6

Redox buffers Optical probe

Subtotal

5.2.3

Effects of radiation on optical components and spectra

Total operating 5.2

funds for

Task Group

(continued) Fiscal

year

1976

1977

I.978

1979

1980

198P

2 5

4 5

5 5

6 8

1982

1983

1984

1985

20 -

6Q -

50 -

40 -

1986

Table

6.5.3.2.

Capital Applicatian

5.2

Miscellaneous

5.2

Inert

atmosphere

5.2

Carey

spectrophotometer

5.2

Tunable

ultraviolet

laser

equipment 5.2

funds

Total capital Task Group

item

equipment funa KequiPements for af spectraphatsmetric methods (costs in 1QBQ dallars)

6 alpha

box

Task

Grsup

5.2

28 45 3Q

for

6-47

6.5.4

... .... :<px

... ..... 5::s

& & .....

:...;..... . >s

....

:<.>> ,..L

t.:.m

Facilities

Most of the basic studies and initial development efforts will be performd in existing facilities of rather modest Sequirements (analytical laboratories with standard hoods). FOK work in radioactive m e l t s , space and facilities are available at the TransuPanium Laboratory or the Analytical Chemistry Hot-Cell Facility in Building 3019. Engineering installations in which in-line measurements are to be m d e w i l l a l s o serve as facilities for this task because the in-line measurements made therein may uncover practical deficiencies in the methods. In addition, installations containing large quantities of salt sometimes present opportunities for stability studies and calibrations that are not feasible i n small research melts. Application of in-line spectrophotometric methods to engineering facilities is expected to be more limited during t h e early stages of the Program because the installation o f optical devices will require more extensive modification of the equipment than Will electroanalytical probes. Initial demonstration of in-line spectrophotometry may be m d e in the Analytical Test Facility (Task Group 5.6).

6.5.5

Task 5.2.1

Fuel salt analysis

Research and development studies carried out to date have been directed toward the characterization and identification of solute species of interest, and to the assessment of the potential of spectrophotometry for their determinations. These studies have lead t o identification of important solute species, to an understanding of the coordination of transition metal and actinide ions in these solvents, amd to the analytical determination of several solute species, including uranium. A review of this basic research is given in Section 6 . 3 . 3 . 2 . It is expected that a strong emphasis OR fuel analysis will continue throughout the early stages of the program until materials problem are resolved. Our earlier work was performed in melts of MSRE solvent composition and many of our measurements, particularly spectral sensitivities, will have to be repeated in the thorium-bearing MSBR fuel s a l t . It is important to carry out both spectral studies and electrochemical studies (Task 5.1.1) of solute species in MSBR melts. These two d i f ferent types of studies augment each other in that they yield mutually beneficial information derived from different characteristics of the ion in question. Also, each technique is vulnerable from different interferences since the measured characteristic is different. Electrochemical studies are more easily adapted to in-line measurements, but, in general, they yield indirect or inferred results. Spectroscopy has proceeded, on an experimental and theoretical basis, to a stage where it can yield direct results as to the identity, coordination, and eoncentration of amenable species (in general, transition metal ions). At the present state of the art, spectral studies can be carried out on very small volumes of sample - thus permitting the characterization of rare or hazardous materials. There are times when a comparison measurement of both chemical activity, by electrochemistry, and chemjlcal concentration,

6-48 by s p e c t r o s c o p y , would be of b e n e f i t . En g e n e r a l , s p e c t r a l measurements can b e made w i t h mre p r e c i s i o n 80 t h a t o v e r l a p p i n g a b s o r p t i o n peaks can b e resolved; ~ o ~ ~ p utte ec hr n i q u e s s a n be and have been a p p l i e d to such data t r e a t m e n t .

PreviBus s p e c t r a l deteminations of U3+$ in whish a sample had t o b e t r a n s f e r r e d from a n experimental f a c i l i s y t o a spectra% cell, has ~ h ~ t s n that r e l i a b l e v a l u e s can r e s u l t , b u t that t h e transfer is very c r i t i c a l . Thfs area must b e f u r t h e r studied s o t h a t the parameters a f f e c t i n g sample transfer are c l e a r l y d e f i n e d . A comparison of s p e c t r a l and e l e e t r o e h d c a l r e s u l t s w i t h v a r i a t i o n of t r a n s f e r pro~eduresw i l l be de. . A s a r e s u l t of t h e s e studies, a r a t h e r p r e c i s e procedure f o r g e n e r a l sample t r a n s f e r w i l l be developed.

6-49

6.5.5.2

Subtask 5.2.1.2

B e t e ~ d n a t i o nof t o t a l uranium

The neasuremetat of small v a r i a t i o n s i n t h e concentration of uranium i n fuel i s n e c e s s a r y t o e n s u r e n u c l e a r s t a b i l i t y i n t h e o p e r a t i o n of molten salt r e a c t o r s . During t h e o p e r a t i o n of t h e NSRE, i t w a s demonstrated t h a t r e a c t i v i t y b a l a n c e measurements w e r e c a p a b l e of d e t e c t i n g s h o r t t e r m changes in uranium c o n c e n t r a t i o n mch more preciselby t h a n e x i s t i n g methods of chemical a n a l y s i s . In t h e case of a ibreede~r e a c t o r , however, c o n c u r r e n t d e c r e a s e s i n the c o n c e n t r a t i o n of uranium and thorium would have o p p o s i t e and c a n c e l l i n g e f f e c t s on r e a c t i v i t y ; ~ O K ~ B V ~the T , %eIllSVal of f i s § i O H n p r o d u c t s & r i l l CQIllPlbicate t h e C a ~ C U h t i O nOf a lOng-terUl r e a c t i v i t y b a l a n c e . Thus, t h e v a l u e of r e a c t i v i t y measurements f o r det e r m i n i n g uranium c o n c e n t r a t i o n could b e comp~~rn%sed and a h i g h l y reproducibke ~ t h o d will b e needed for the direct in- line measurements a t the r@qUiKed p r e c i s i o n . C d c U l a t i o n s have indicZitEd t h a t in a Oble-CIlI p a t h O f f u e % t h e abSOPbtaHlce O f t h e u4+ peak in t h e near infrared (1890 lXll> can b e measured w i t h a r e p r o d u c 5 b i l i t y sf about 0.1. percent. A b s o ~ p t i ~ n by o t h e r ions that have been measured i s minimal i n t h i s r e g i o n . The acfiievenent of such r e p r o d u c i b i l i t y would r e q u i r e a p r e c i s e l y d e f i n e d o p t i c a l p a t h t h a t could b e o b t a i n e d w i t h EL diamond-windowed o p t i c a l c e l l o r a s l o t t e d probe (Subtask 5.2.1.9) and e i t h e r the o x i d a t i o n of a l l of the uranium t o ~ 4 +o r a c o r r e c t i o n f o r t h e small fraction sf Y3+ in t h e f u e l . It should b e emphasized t h a t the accuracy of these measu~ementswill depend OR c a l i b r a t i o n and w i l l not n e c e s s a r i l y match the precision.

In t h e o r y , t h e r e p r o d u c i b i l i t y could be f u r t h e r improved by a t least an

..m

o r d e r of magnitude by ehe u s e of h i g h - i n t e n s i t y l i g h t from a tunable %ase~ to permit measurements through longer path l e n g t h s or by m r e p r e c i s e measurement of transn-dtted l i g h t from a n i s o t o p i c a l l y e x c i t e d SQUrce. %he achieVelIlelrat sf t h e theOKeticd p s t e a f t i a l f o r pKEkCtiCal KK)llitorhg SySteIlls Would require StKingell$ W t 2 a S U P e S to C O I l t - P O E @Xp@rimental v a r i a b l e s , such a s temperature and v i b r a t i o n , and to a p p l y C O K P ~ C tions f o r v a r i a t i o n s i n t h e c o n c e n t r a t i o n of even weakly a b s o r b i n g ions, for t U P b F d i t y , afld f O l r effects Sf l I l d f Z COmpoSi$ion On t h e h % @ l l S i t ySf uranium a b s o r p t i o n . With d i g i t a l data p r o c e s s i n g and c a r e f u l d e s i g n of t r a n s d u c e r s such extreme p r e c i s i o n a p p e a r s f e a s i b l e , and a significant development e f f o r t i s j u s t i f i e d because of t h e v a l u e of a s s u r a n c e 0 % fuel s t a b i l i t y d u r i n g r e a c t o r o p e r a t i o n s . The p r a c t i c a l i t y ~f h i g h - p r e c i s i o n s p e c t ~ ~ p h o t ~ m e t rmeasurements ic will be assessed i n mre d e t a i l by e x a d n i n g measured o r p r e d i c t e d s p e c t r a of i o n s that may b e p ~ e s e ~in~ stu f f i c i e n t ~ ~ ~ e e ~ n t r at toi aofnf e c t t h e measurements a t P09Q m 9r e p e a t i n g measurements of t h e a b s o r p t i o n spectre selected ions, e ~ t t m t a t i n gthe effects of t u r b i a i t y , experiments t h a t a9.e conceived t o demonstrate t h e f e a s i b i l i t y of t h e method. U n t i l a tunable laser qnd perhaps an i n - l i n e probe are a v a i l a b l e , s p e c t r a l masurements of u4 will b e limited t o b a s i c s t u d i e s of changes in intensity of a b s o r p t i o n and peak s h a p e s w i t h v t ~ r i a t i o n s i n 6 B D . l ~ ( 3 % i t i O l l in t h e Pegion Sf the KefeIrenCe fuel d X t U k - e . SoEle Of these data are a v a i l a b l e from earlier r e s e a r c h studies.65 fieri approp r i a t e equipment i s available, measurements w P B l b e d e , probably i n

.... ....

, r . < *

6-50

the Analytical T e s t Facility, m d e r conditions predicted t o yield a r e p r o d u c i b i l i t y of abaut 0.1 percent. The e x p e r i m e n t a l d a t a will be compared w f t h the theoretical p r e d i c t i o n s and any d e v i a t i o n s w i l l be s u b j e c t e d t o e r r o r a n a l y s i s . C a l c u l a t i o n s will t h e n be performed t o p r e d i c t t h e requiPefnents f o r @Xtel%dhgthe t e c h n i q u e t o any preS@l@Cted level of r e p r o d u c i b i l i t y and t o estimate the development c o s t i n c u r r e d On t h e basis of recommendations from r e a c t o r p h y s i c s and s a f e t y groups, a t a r g e t pre~isionw i l l b e e s t a b l i s h e d and t h e n e c e s s a r y development work w i l l b e performed t o p r o v i d e a d e v i c e f o r t e s t i n g i n the GSTF or another e q u a l l y appKQpPiate f a c i l i t y . a

Other areas where total uranium needs t o be d e t e ~ ~ ~ ~ are i n e di n waste and p r o c e s s streams and i n the s a l t effluent froam t h e f l u o r i n a t i o n f a c i l i t y . These measurements are n e c e s s a r y f o r p r e c i s e i n v e n t o ~ g .c o n t r o l and w i l l be a p p l i e d t o streams that shoudd c o n t a i n no uranium or9 a t most, a v e r y By m k i n g use O f Et v e r y S e n s i t i v e u l t r a l Q W Concentration sf uranium. v i o l e t peak of U4*$ at 235 m, i t should be p o s s i b l e to d e t e s t <lO ppm o f uranium. This a b s o r p t i o n peak of W4* f a l l s o u t s i d e t h e t r a n s p a r e n c y range sf diamond, t h e r e f o r e windowlbess cells must b e used for t h i s a p g l i c a t i o n . Work d i r e c t e d toward p r o p e r c e l l geometry and assessment of ultimate s e n s i t i v i t y will b e c a r r i e d out. I n t h e r e d u c t i v e extraction p ~ ~ c e streams, ss sm1E amounts of Us+ will b e determined, as d i s c u s s e d in Subtask 5.2.1.1.

6-5.5.3

Subtask 5.2.1.3

Determination of plutonium

The spectrophotometry of pbutunium compournds i n bre@der compositions w i l l be studied t o p r o v i d e d a t a f o r t h e development of a n a l y t i c a l methods and t o c o n t r i b u t e to t h e basic IXlderstandhg 0% t h e C h e ~ S t P yof pdUtoniUm in t h i s medium. P r e l i m i n a r y a b s o r p t i o n spectra f o r Pu3+ i n molten fluoride salts66 e&ibit a C Q ~ ~ Pp a~t tXe r n w i t h a wide v a r i a t i o n of a b s o r p t i o n intensities. It a p p e a r s t h a t a b s o r p t i o m e t r i e methods should be f e a s i b l e b o t h fur t h e p r e c i s e measurement of h i g h c o n c e n t r a t i o n s of BuF3 t h a t would b e p r e s e n t d u r i n g s t a r t - u p w i t h plutonium f u e l and f o r trace concentrations generated by n u c l e a r r e a c t i o n s . There appears to be no e d i a t e need f o r in-line a n a l y t i c a l methods f o r plutonium. Basic studies w i l l b e c a r r i e d o u t as soon as p r a c t i c a l , however, t o determine whether i t s p r e s e n c e m y i n t e r f e ~ ew i t h t h e d e t e r m i n a t i o n of o t h e r ConStituCZSltS.

6.5.5.4

Subtask 5.2.1.4

Determination of p r o t a ~ t i n i u ~

CCXI~PO~. of the c o n c e n t r a t i o n of p r o t a c t i n i u m i s nesessa~grfor a t t a i n i n g a high b r e e d i n g r a t i o i n t h e r e a c t o r . The e q u i l i b r i u m l e v e l of protact i n i u m w i % %be t o o low t o b e d e t e ~ m i n e di n t h e p r e s e n c e of uranium. However, the s p e c t r a l d e t e r m i n a t i o n of p r o t a c t i n i u m F p i l l B e e v a l u a t e d for a p p l i c a t i o n t o salt streams i n t h e p r o c e s s i n g system which c o n t a i n . b W e r COnCentratfons Of U r 8 l I i U I I l , SOIlle p r d h L h 3 P y s p e c t r a l Studies of Pa4* have been completed. Based on these s t u d i e s , i t should b e p o s s i b l e t o determine pa49 i n p r o c e s s i n g streams o r o t h e r f l u o r i d e m e l t s of

6-51

interest down to a Concentration of less than 50 ppm. It may be possible to extend t h i s limit to lower concentrations as further studies are carried out.

he precision and sensitivity of the spectral determination sf ~ a 4 +w i l l be evaluated for in-line measurements with improved spectrophotometric techniques. Capabilities of the spectral methods will be compared with those of electroanalytical methods in similar applications. A search will also be made, in melts that are carefully freed of oxide, for ultraviolet absorption 0% 1fa5+. sensitive ~ a 5 +determination would support basic studies of the chemistry of protactinium. 6 5 5.5 e

subtask 5 2 I.5 a

Determination of US+

he absorption spectrum of UPS has been measured in MSRE €ere1 solvent. G 7 The spectrum includes a sharp peak at 1465 nm that is sufficiently intense for the measurement of moderate concentrations of US+ in fluoride melts. The spectrum will b e remeasured in melts of breeder composition, using diamond-windowed cells to provide improved accuracy for abscrrpt i v i t y measurements. These calibration measurements w i l l be used to provide analytical support for fuel reconstitution studies. Devices for in-line measurement will be developed if needed. 6.5.5.6

Subtask 5.2.1.6

Determination of oxygenated species

An understanding of the chemistry of traces of oxide in fluoride melts is sf recognized importance to the stability of reactor streams and to possible alternate processing schemes. It is probable that oxide can etc. he exist in several forms in t h e fuels, such as 0 2 - $ OH-, MI:-, complete evaluation of the possible interactions of oxide ions requires a knowledge of the type of oxygenated species that are present. Studies in this area c~uldalso lead to new analytical approaches t o the important measurement of oxide activities in MSBR streams. If a s t r o n g l y absorbing oxygenated species is found to be in equilibrium with oxide i o n s , its measurement could provide the basis for an in-line spectral method for the measurement of oxide activity. APSO, the determination of trace elements by spectral and other techniques could be affected by the formation of oxide co lexes. The reaction of chromium (VI) and vanadium (V9 with oxide to form the strongly absorbing chromate and vanadate ions will be evaluated as a method for the determination of ucomplexed l o w level 0 2 - , or total oxide. The extraction of OH- into molten NaBF4 will be studied. Once extracted, the hydroxide w i l l be determined by the infrared pellet technique (see Subtask 5.2.3.1). Infrared spectra of oxygen-containing melts will be examined for useful absorptions. Much of the exploratory work will be done in melts t h a t contain no thorium SO that meaningful standard additions can be made without exceeding the oxide tolerance. Any promising approaches d l l then be studied in MSBW fuels for possible in-line applications.

6-52

6.5.5.7

Subtask 5.2.1.7

Measurement of t u r b i d i t y

Some t u r b i d i t y i s expected i n r e a c t o r f u e l and within o t h e r salt streams of m l t e n s a l t r e a c t o r s . Because no p r o v i s i o n s f o r o p t i c a l ~ b s e ~ v a t i o n Of the fuel W @ K e a v a i l a b l e at t h e RE, no e s t i m t i o n O f the degree Of t u r b i d i t y of c i r c u l a t i n g f u e l can be m d e . It w i l l be necessa~yto perform experiments t o obtain estimates of t h e S Q U ~ C ~ and S magnitude of t u r b i d i t y s o t h a t i t s e f f e c t on s p e c t r o p h o t o m e t r i c and other i n - l i n e o p t i c a l methods can b e p r e d i c t e d . A l s o , a n i n - l i n e measurement of t u r b i d i t y could p r o v i d e u s e f u l i n f o r m a t i o n i n v a r i o u s areas s f r e a c t o r o p e r a t i o n s . It has been i n f e r r e d (from t h e r e l a t i v e l y s t a b l e concentrations of t h e more n o b l e c o r r o s i o n p r o d u c t s , i r o n and n i c k e l , i n HSRE f u e l that w a s s u f f i c i e n t l y reducing t o preclude t h e i r presence i n i o n i c form) t h a t these materials are present as p a ~ t i c u l a t emetals of submicros c o p i c size.E8 P a r t i c l e s i n t h i s s i z e range could cause s i g n i f i c a n t a t t e n u a t i o n i n t h e u l t r a v i o l e t t r a n s m i s s i o n of t h e fuel and t h u s interf e r e w i t h measurements i n this r e g i o n of h i g h l y i n t e n s e a b s o r p t i o n s . PnterfePenCe at IORgel- WaV'ZleRgth.5 With h l p o r t a n t deteXlXhatiOns S U C h as t h e p r e c i s e d e t e r m i n a t i o n of u ~ a ~ ~ i(Subtask um 5.2.1.2) could b e i n troduced by bubbles of heliun and g r a p h i t e p a r t i c l e s . I f t h e e f f e c t of turbidity is l o w , an empirical correction that is c o ~ ~ e l a t ewith d a measbarenen%of l i g h t scatter would probably s u f f i c e . M ~ r es e r i o u s interfel~encecorald b e handlea e i t h e r by c h a r a c t e r i z i n g t h e s c a t t e r i n g miterial and computing i t s c o n t r i b u t i o n ts t h e a t t e n u a t i o n , 8%by pretreatment of t h e streams to reduce t u r b i d i t y . This could be accomplished by f i l t r a t i o n , settling, or c h e d c a l o x i d a t i o n . ,%ny a d d i t i o n a l b e n e f i t s could r e s u l t from t h e o p t i c a l c h a r a c t e r i z a t i u n of p a r t i c u l a t e matter i n reactor streams. The m o s t obvious is the d i r e c t measurement sf t h e c o n c e n t r a t i o n and s i z e d i s t r i b u t i o n of helium bubbles t o assist i n a c h i e v i n g optimum s t r i p p i n g of t h e h i g h c r ~ ~ ~ - s e c t i135Xe. on A rather complete c h a r a c t e r i z a t i o n of t h e t o t a l particulate mtter in s a l t streams would p r o v i d e a new parameter f o r t h e evaluation of r e a c t o r o p e r a t i o n . For i n s t a n c e , i t could provide e a r l y warning of p r e c i p i t a t i o n s f fare%c o n s t i t u e n t s by b o r n o r unexpected r o u t e s . It should be emphas i z e d t h a t s i n c e l i g h t s c a t t e r i ~ gt e c h n i q u e s i n v o l v e a d i r e c t r a t h e r than a s u b t r a c t i v e m e a ~ ~ ~ e they ~ t ~can n t be used t o p r o v i d e some of the most s e n s i t i v e of o p t i c a l ~ ~ ~ a s u ~ e ~ The ~ e ns et ns s. i t i v i t y i s p r i m a r i l y a funct i o n of t h e i n t e n s i t y of i n c i d e n t l i g h t . I n a t h e r m a l l y s t a b l e m e d i m such as molten salts, d e t e c t i o n limits could be extended to almost any d e s i r e d l e v e l by u s i n g lasers as a s o u r c e of i n c i d e n t l i g h t . A f r u i t f u l are? f o r this type of I I I ~ ~ S U K ~ would E ~ ~ b e i n t h e s t u d y of t h e g e n e r a t i o n ~f d i s p e r s i o n s sf bismuth metal d u r i n g r e d u c t i v e extraction steps of processing. I f p a r t i c u l a t e matter t h a t i s o r i g i n a l l y p r e s e n t i n t h e entering steam is l a r g e l y remvect by reductive extraction, QP if bismuth p a ~ t i c u l a t ep~o s s e s s some o p t i c a l l y d i s t i n g u i s h a b l e c h a r a c t e r i s t i c , s c a t t e r i n g measurements coul be a p p l i e d t o a s e n s i t i v e method f o r t h e asurement of bismuth i n r e t u r n streams. S c a t t e r i n g essential in-line t e c h n i q u e s could r e a d i l y b e a p p l i e d t o t h e measurement of p a r t i c u l a t e s i n cover g a s e s . I n this i~stancet h e streams could b e d i l u t e d t o a c o n c e n t r a t i o n that would permit t h e measurement of s c a t t e r i n g by i n d i vidual p a r t i c l e s .

L...A

6-53 Initial t u r b i d i t y measurements will be m d e by u s i n g t h e viewing p o r t s t h a t are to b e i n s t a l l e d on t h e salt monitoring vessel of t h e GSTFp. Although the geometry of t h i s system w i l l se~erelylimit t h e s c a t t e r i n g a n g l e , these d a t a should b e adequate ts estimate t h e o r d e r of magnitude sf i n t e r f e r e n c e t o a b s o r p t i o m e t r i c measurements t o b e expected from p a r t i c u l a t e metals and the relative c o n t r i b u t i o n of helium bubbles ts t h e t u r b i d i t y of fuels. When a tunable laser i s available, measurements of s c a t t e r i n g a t d i f f e r e n t wavelengths w i l l be used i n t h i s f a c i l i t y t o c r u d e l y estimate p a r t i c l e s i z e d i s t r i b u t i o n . More d e f i n i t i v e experiments w i l l b e made i n t u r n of t h e s i z e d i s t r i b t u i o n of p a r t i c u l a t e m e t a l s that are g e n e r a t e d by t h e r e d u c t i o n of r e s e a c h m e l t s o r of t h e f u e l i n t h e h a l y t i c a 1 T e s t F a c i l i t y . It i s a n t i c i p a t e d t h a t a number of more conv e n i e n t and s o p h i s t i c a t e d d e v i c e s f o r p a r t i c l e s i z e c l a s s i f i c a t i o n wiP% b e g e n e r a t e d by programs concerned with p o l l u t i o n abatement. These developments w i l l be a p p r a i s e d f o r a p p l i c a b i l i t y t o molten s a l t masurem a t s . I n g e n e r a l , techniques t h a t u t i l i z e wavelength and p o l a r i z a t i o n parameters r a t h e r t h a n a n g l e of scatter w i l l be s e l e c t e d because of t h e i r a p p l i c a b f l i t q t o s i m p l i f i e d c e l l d e s i g n s . P r a c t i c a l i n - l i n e cells will be d e v e l ~ p e dand used t o c h a r a c t e r i z e p a r t i c u l a t e matter i n f u e l and processing streams of various t e s t f a c i l i t i e s . From the data obtaimed, computer programs d B 1 be developed t o g e n e r a t e t u r b i d i m e t r i c c o r r e c t i o n s f o r spectrophotometric data.

,.&

.:;*"I

.... .:.=

...s ....

4.5.5.8

Subtask 5.2.1.8

Study of t e l l u r i u m in f u e l

6.5.5.9

Subtask 5.2.1.9

Development of a diamond-tipped optical probe

The s i m p l e s t system for i n - l i n e s p e c t r a l a n a l y s e s of molten s a l t r e a c t o r streams would i n c o r p o r a t e an o p t i c a l probe. With p r o p e r o p t i c a l d e s i g n , a l i g h t beam could be d i r e c t e d i n t o and out of a m l t e n s a l t stream through ~ n l yone p e n e t r a t i o n . Light F T Q U ~be ~ t r a n s m i t t e d w i t h i n the probe by int e r n a l r e f l e c t a n c e . The probe would be s l o t t e d t o allow t h e light beam t o pass through a h o r n length of t h e molten s a l t . The probe material must be t r a n s p a ~ e n t ,of high r e f r a c t i v e index, and compatible w i t h molten salts. tb diaIROnd-tipped O p t i c a l probe Would meet these Kequir@men%s98% t h e fluel s a l t , and s t u d i e s l e a d i n g t o t h e f a b r i c a t i o n and t e s t i n g of such a d e v i c e

6-54

w i l l be c a r r i e d o u t . A I I I Q K ~ d e t a i l e d d e s c r i p t i o n of t h e p r i n c i p l e s of o p t i c a l probes is p r e s e n t e d i n Subtask 5.2.3.6.

6.5.6

Task 5.2.2

LiC1 a n a l y s i s

S p e c t r a l c h a r a c t e r i z a t i o n s l e a d i n g t o i n - l i n e a n a l y t i c a l methods w i l l U l t b a t e l y be performed f o r the V a r % Q U S s o l u t e Species expected to be p r e s e n t i n molten P i t h i m c h l o r i d e streams o f t h e p r o c e s s i n g system. Except for r e q u e s t e d a n a l y t i c a l s u p p o r t s t u d i e s , a c t i v e i n v e s t i g a t i o n s in t h i s medium w i l l b e d e f e r r e d because o f mare u r g e n t problems in o t h e r areas. This should a c t u a l l y l e a d t o e f f e c t i v e utilization of t h e r e s e a r c h and development r e s o u r c e s s i n c e r e s e a r c h i n t h e less h o s t i l e c h l o r i d e media will. p r o v i d e much of t h e needed d a t a and the a n a l y t i c a l thoroughly ~ e e s t a b l i s h e d a f t e r a d d i t i o n a l engir e q u i r e m n t s w t l l be ~ t l ~ n e e r i n g experiments. S p e c t r a l i n v e s t i g a t i o n s will y i e l d the s a m e type of u s e f u l i n f o m a t i o n as d i r e c t a n a l y s e s of s o l u t e s p e c i e s i n lnolten l i t h i u m c h l o r i d e as d e s c r i b e d i n t h e f u e l a n a l y s i s section (6.5.5, Task 5 . 2 . l ) , b u t w i t h easier a p p l i c a t i o n .

6.5.6.1

Subtask 5.2.2.1

Determination of uranium

It i s expected t h a t uranium compounds i n l i t h i u m c h l o r i d e w i l l e x h i b i t s t r o n g a b s o r p t i o n s t h a t caw b e used t o develop i n - l i n e m e t f n ~ d sof c o w p e t i t i v e s e n s i t i v i t y w i t h e l e c t r o a n a l y t i c a l methods. The s p e c t r a of uranium i n various o x i d a t i o n s t a t e s w i l l be c h a r a c t e r i z e d t o determine b a s i c chemical d a t a such as c o o r d i n a t i o n , and t h e a p p l i c a b i l i t y of s p e c t r a l methods f o r t h e i n - l i n e monitoring of uranium t r a n s f e r i n t o t h e l i t h i U I B C h l o r i d e proce§s StreaElS. 6.5.6.2

Subtask 5.2.2.2

Determination of plutonium

Measurable c o n c e n t r a t i o n s of plutonium m y e n t e r t h e lithium c h l o r i d e phase p a r t i c u l a r l y d u r i n g i n i t i a l p ~ ~ e s s f nf ogr a r e a c t o r t h a t w a s s t a r t e d up on plutonium f u e l . It i s a n t i c i p a t e d t h a t PuCl3 w i l l e x h i b i t a s t r o n g and complex s p e c t r ~t h a t can prove u s e f u l f o r s p e c t r a l measurements and may offer i n t e r f e r e n c e s t o o t h e r s p e c t r a l d e t e r m i n a t i o n s . S p e c t r a l c h a r a c t e r i z a t i o n s of t h e v a r i o u s s t a b l e oxidation states of plutonium i n l i t h i u m c h l o r i d e melts w i l l be made t o assess t h e p o t e n t i a l for its h - l i n e dete3XlhatioR .Xld it§ effect Oaf Other a n d y S @ S .

S i g n i f i c a n t c o n c e n t r a t i o n s of oxide i n m l t e n l i t h i m c h l o r i d e are exp e c t e d to l i m i t the rates of t r a n s f e r of f i s s i o n p r ~ d u ~ tbetween s bismuth and h a l i d e streams. For t h i s reason, and because o x i d e m y attack s t r U C t U K d i l I & e k i d S , the ChemistrJ’ of oxide in HithiUItl chloride? w i l l have t o b e studied. The most promising s p e c t r a l approach will be

6-55 t o s e a r c h f o r i n t e n s e l y a b s o r b i n g oxycomplexes t h a t may be formed by t h e r e a c t i o n of o x i d e wfth a s o l u t e t h a t i s normally p r e s e n t i n t h e p r o c e s s i n g streams o r w i t h some innocuous added s o l u t e . W s y s t e m a t i c survey of t h e a b s o r p t i o n s p e c t r a o f v a r i o u s s o l u t e s i n oxide-bearing l i t h i u m c h l o r i d e w i l l b e conducted throughout t h e range of s p e c t r a l t r a n s m i s s i o n of t h i s medium. The most u s e f u l a b s o r p t i o n s w i l l be chara c t e r i z e d more f u l l y f o r a p p l i c a t i o n s t o i n - l i n e measurements. I f i t proves n e c e s s a r y t o add a s o l u t e t o develop o x i d e a b s o r b a n c i e s , the. s t a b i l i t y of t h i s s o l u t e i n p r o c e s s streams and i t s p o t e n t i a l e f f e c t on t h e r e a c t o r system w i l l be e v a l u a t e d . The measurement sf a b s o r p t i o n s i n s o l i d samples dll a l s o b e i n v e s t i g a t e d .

6.5.6.4

Subtask 5.2.2.4

Study of hydroxide

Hydroxide i n molten l i t h i u m c h l o r i d e would cause c o r r o s i o n of s t r u c t u r a l m e t a l s and many ceramic materials t h a t might be used i n t h e f a b r i c a t i o n of a n a l y t i c a l d e v i c e s . Unless i t is c o n t i n u a l l y r e p l e n i s h e d , it a p p e a r s l i k e l y t h a t t h e c o n c e n t r a t i o n o f uncomplexed hydroxide i n c h l o r i d e p r o c e s s i n g streams w i l l b e decreased t o levels below s p e c t r a l d e t e c t i o n limits through r e d u c t i o n by t h e bismuth streams. T h e r e f o r e , t h e i n i t i a l a c t i v i t i e s i n t h i s t a s k w i l l be d i r e c t e d towards t h e development of h i g h l y s e n s i t i v e methods f o r t h e d e t e r m i n a t i o n of hydroxide i n samples of l i t h i u m c h l o r i d e . Nethods based on i n f r a r e d a b s o r p t i o n appear t o be the most p r o d s i n g . These w i l l be t e s t e d b o t h fop t h e measurement of hydroxide t h a t has been p r e c o n c e n t r a t e d by e x t r a c t i o n i n t o i m i s c i b l e HaBF4 m e l t s and f o r t h e measurement of s o l i d s t a t e hydroxide compPexes i n p r e s s e d p e l l e t s . If u n u s u a l l y s e n s i t i v e s o l i d stare a b s o r p t i o n s are d i s c o v e r e d , a s e a r c h w i l l b e made i n m e l t s f o r s i m i l a r a b s o r p t i o n s t h a t i n s i t u determinations. could serve as a b a s i s f o r --

6.5.6.5

..:.&

Subtask 5.2.2.5

Study of s p e c t r a of t r a n s i t i o n m e t a l i o n s

The s p e c t r a l c h a r a c t e r i z a t i o n of d i v e r s e t r a n s i t i o n metal i o n s i n l i t h i u m c h l o r i d e m e l t s w i l l p r o v i d e b a s i c chemical d a t a and i n f o r m a t i o n f o r p o s s i b l e a n a l y t i c a l a p p l i c a t i o n s f o r t h i s medium. It i s a n t i c i p a t e d t h a t t h e i n t e n s i t y of a b s o r p t i o n s r e s u l t i n g from d-d t r a n s i t i o n s w i l l b e s i g n i f i c a n t l y enhanced i n t h i s m e l t ; t h e r e f o r e , u s e f u l a n a l y s e s of i o n s such as c o r r o s i o n p r o d u c t s w - i l l be p o s s i b l e a l t h o u g h mutual i n t e r f e r e n c e s may a l s o be a c c e n t u a t e d . Because a c t i n i d e s may b e p r e s e n t i n t h e s e processi n g stream d u r i n g s p e c i a l o p e r a t i o n s o f t h e p r o c e s s i n g system, t h e i r ions w i l l a l s o b e measured. S p e c t r a l s t u d i e s will b e performed as t i m e p e r m i t s of a l l such i o n s t h a t may be p r e s e n t in t h e l i t h i u m c h l o r i d e streams w i t h p a r t i c u l a r a t t e n t i o n t o lower o x i d a t i o n states. Related s t u d i e s by o t h e r s have been m d e i n similar b u t n o t i d e n t i c a l m e l t s . Missing i n f o r m a t i o n w i l l b e g a t h e r e d e x p e r i m e n t a l l y and an assessment of a n a l y t i c a l s a p a b i l i t i e s w i l l be rnade.

6.5.6.6. A s d e s c r i b e d i n "lore detaFab i n Subtask 5 . 2 . 3 . 4 , a s i m p l e optical probe Offer Bi@lifiCZ%nt a$Vantage§ f o r patastical spC2ctKEI.k €ileasUrem@ncs i n lithium chloride m e l t s . It i s expected that syntketis s a p p h i r e , which has s u i t a b l e o p t i c a l p ~ ~ p e r t i e swill. , be compatible w i t h molten l i t h i m c h l o r i d e . Design, f a b r i c a t i o n , and evakuation of such a probe f ~ s rp e c t r a l a n a l y s i s will be made.

WOdd

6,5.7

Task 5.2.3

Coolant s a l t a n a l y s i s

The h i g h e s t p r i o r i t y f o r r e s e a r c h and development s t u d i e s under t h i s s u b t a s k w i l l be a s s i g n e d to t h e g e n e r a t i o n of methods t o s u p p o r t imminent experiments a t t h e CSTP t h a t are designed to e v a l u a t e t h e p o t e n t i a l of t h e k13P4 CQolant for t h e COIztahment O f tritium (Cf. Task 5.1.3). % m e d i a t e efforts w i l l b e ~ o n c e n t ~ a t eon d urgently- needed methods f ~ a : t h e s p e c t r a l a n a l y s i s of d i s c r e t e samples rather t h a n t h e l o n g e r t e r m o b j e c t i v e of providing i n - l i n e analyses. Priority tdl1 also be g r a n t e d to spectral support of a s s o c i a t e d development e f f o r t s of o t h e r areas sf the Analytical Chemistry Research and Development P r ~ g ~ a msuch , as t h e i d e n t i f i c a t i o n of condensate from t h e cover gas of the CSTF (Subtask 5 . 3 . 1 . 3 ) . I n f o m a t i o n gained i n t h e s e developments w i % % , i n t u r n , b e a p p l i e d to -im s i t u studies s f p r o t o n Ch@€iliStK). in f l u s r o b o r a t e melts and t o t h e developmplt u f i n - l i n e methods t h a t will u l t i m a t e l y be needed IEOP a more efficient analytical system. Other s o l u t e s , such as oxide and K e d O X b u f f e r c s t ~ p l e s , S f p o s s i b l e s i p i f i c a n c e t o t r f t i u C O n t a i R When a l t e r n a t e c ~ ~ l a n t s ment dll be s t u d i e d on a ~ O W ~p ~ S i o r i t yb a s i s . are proposed, s p e c t r a l methods w i l l be a p p l i e d t o g e n e r a t e b a s i c chemi c a l d a t a on s o l u t e s i n t h e s e materials and t o p r o v i d e any needed analytical support for t h e i r e v a l u a t i o n .

6.5.7.1

Subtask 5.2.3.1

Determination of BP38H- and B P s g -

The present a n a l y t i c a l i n v e s t i g a t i o n s i n d i c a t e t h a t t h e major f r a c t i o n of combined h y d b - ~en i n NaF-NaBP4 c o o l a n t melts i s p r e s e n t as t h e relatively s t a b l e BF30H- ion, t y p i c a l l y i n COnCentrZitiOR.5 O f about twenty ppm as hydrogen. In t h e ~efereneereactor design t h i s c o n c e n t r a t i o n corresponds t o a q u a n t i t y of hydrogen t h a t i s comparable t o t h e total tritium p r o d u c t i o n d u r i n g the o p e r a t i n g l i f e t i m e of an MSBR r e a c t o r . Therefore, it w i l l b e sf major i n t e r e s t i n the deuterium i n j e c t i o n experiment a t t h e CSTF t o d e t e m i n e het the^ deuterium, a s t a n d - i n ~ O P tritium, san be i n c o r p o r a t e d i n t o the h y d r ~ ~ y f l ~ c ~ r ~ bioo nr .a t eThe only e s t a b l i s h e d method f o r distinguishing between hydrogen and deuterium i n this ~ ~ ~ i%p t h~e b.fra-K@d n d pellet hat present, the d e t e c t i o n limit (established by s t a n d a r d a d d i t i o n s o f NaBF30H) i s a b ~ t one ppm. E s s e n t i a l l y id9aatical s e n s i t i v i t i e s are predicted70 f o r t h e measurement ~f BF3OB-. A t l e a s t an srder of magnitude imp~svera8gnt i n d e t e c t i o n lidt will b e needed t o e v a l u a t e the r e s u l t s of the d e u t e r i m

U."

6-57

injection eqeriments, The use of thicker pressed pellets w i l l be investigated as a means of improving the sensitivity 0% t h e infra-red method. These development studies will a l s o provide verification of the calibration for BP38PI- measurements because standard additions O F deuterated c o ~ o u n d scan b e de w i t h o u t contamination. The techniques developed will also b e used in s u p p o r t of basic chemical studies on the control of BF3QdH- concentrations in melts. Studies of t h e direct i n f r a red measurements of these ions in melts w i l l b e resu~ed:to evaluate t h i s approach for t h e development of in-line analytical. methods.

.6.5.7.2

Subtask 5.2.3.2.

B e t e r d n a t i o n 0% oxide

Many oxides g hovzever, Uncomplexed 02- i o n may not e x i s t in NaBF4 readily d i s s o l v e in t h i s meit ana the nature of t h e ~ ~ S S P W I o x i d e species must be characterized in order to assess t h e i r e f f e c t on CorrQsiVity and p o s s i b k RlOdes Of tritfW transport thrC?Ugh %he C O O h n t s a l t . Por these types of s t u d i e s , ifaflPaK@d analyses of molten and s o l i d NaBF4 will be used to e s t a b l i s h t h e molecular species t h a t are present, Si~ilarinvestigations will be performed on alternate cooEant composit i o n s whFch may be proposed d u r i n g the course of the program.

6.5.7.3

alternate coolants (AC) A s other coolant melts are developed to an experimental stage, an assessment of their interaction with tritium escaping %rum the f u e l salts w i l l need to be investigated. These considerations w i l l require a knowledge sf t h e type and concentration of protonated species that are present in the melt. 'kfdeedar spectroscopy, using infrared or near-infrared measureaents, will b e applied in these studies. Recent research7' has shown t h a t infrared measurements can be based t o measure complexes of anions including hydroxides with di- and trivalent cations at ppb eoncentrations.

... .... .....

T h i s solid measurement technique w i l l be a p p l i e d to the

characterization and d e t e ~ d n a t i o nof protonated species i n the new coolants, and p o s s i b l e extensions to direct measurements in melts w i l l be s t u d i e d . Methods developed in t h i s s u b t a s k will be used to provide analytical support for experiments t o study the exchange capabilities sf protonated species with deuterium or tritium.

6.5.7.4

subta§k 5 . 2 . 3 . 4

D e t e r ~ m t i o nof corrosion product ions

... .... ..... %E,

..:&

....

X.*'

...

....

Earlier investigations of t y p i c a h corrosion product ions such as ~ e 2 + $ Ni2*, and C r 3 f , have shown that their absorbancies are t o o weak for p r o f i t a b l e exploitation f ~ in-line r analytical methods i n the present B B R coolant. Also, in the MaBF4 coolant the solubilities were too low to permit proper spectral characterization. It is assumed that the spectra k?xi.P1 be s i d b a r in alternate coolant compositions provided they are made up sf f l u o r i d e salt d x t u r e s . Spectrophotometric studies will

6-58 b e needed f o r t h e s e i o n s and t h o s e of o t h e r components of s t r u c t u r a l a l l o y s t o p r o v i d e b a s i c chemical i ~ - & ~ - ~ t i oand n t o predict possible i n t e r f e r e n c e s w i t h o t h e r s p e c t r a l d e t e r m i n a t i o n s , C h a r a c t e r i z a t i o n of t h e s e s p e c i e s w i l l be made i n m e l t s of proposed a l t e r n a t e c o o l a n t s . Also, the s p e c t r a of c e r t a i n f u e l c o n s t i t u e n t s will be s t u d i e d f o r potent i a l a p p l i c a t i o n t o the d e t e c t i o n of l e a k s i n h e a t exchangers d u r i n g p e r i o d s of i n i t i a l non-nuclea~ o p e r a t i o n .

6.5.7.5

Subtask 5.2.3.5

Study of redox b u f f e r c a n d i d a t e s

For any MSBR c o o l a n t s a l t i t w i l l probably b e d e s i r a b l e t o i n c o r p o r a t e some t y p e sf redox b u f f e r system t o c o n t r o l c o r r o s i o n OF assist i n t K i t 8 W I l cOntahlne€lt. Ill gen@%al,these KedoX Couples ~ 1i l l V % O%Ve P r m l t i v a l e n t s o l u t e s p e c i e s of t r a n s i t i o n metal i o n s , and one OF b o t h of t h e o x i d a t i o n s t a t e s w i l l b e amenable t o s p e c t r a l d e t e r m i n a t i o n s . S p e c t r a l s t u d i e s of proposed redox couples will be made to c h a r a c t e r i z e t h e n a t u r e of b o t h s o l u t e s p e c i e s and t o assess s p e c t r a l methods f o r an i n - l i n e d e t e r m i n a t i o n o f t h e redox c o n d i t i o n of the c o o l a n t .

6.5,7.6

Subtask 5 . 2 . 3 . 6 coolant salts

Development of a n o p t i c a l probe for

The a p p l i c a t i o n of s p e c t r o p h o t o m e t r i c methods t o molten s a l t streams can b e performed much more c o n v e n i e n t l y i f b o t h t h e e n t r a n c e and e x i t beam can be conducted through a s i n g l e p e n e t r a t i o n . For t h i s purpose, a simple o p t i c a l d e v i c e has been developed t h a t i s g e n e r a l l y a p p l i c a b l e t o a l l f l u i d streams for which a s u i t a b l e o p t i c a l material e x i s t s . 4 9 The optical material must b e compatible w i t h t h e f l u i d t o be measured and must Rave a h i g h e r r e f r a c t i v e index. The d e v i c e i s f a b r i c a t e d from a c y l i n d r i c a l s e c t i o n o f o p t i c a l material f o r convenient s e a l i n g i n t o t h e system. F a c e t s ground o n t o t h e e x t e r n a l end o f the material d i r e c t a c o l l i m a t e d beam of l i g h t ( t y p i c a l l y from a t u n a b l e l a s e r ) a l o n g a l o n g i t u d i n a l p a t h i n t h e probe and p r o v i d e a n e x i t window f o r t h e a t t e n u a t e d e x i t beam. A p r i s m a t i c c o n f i g u r a t i o n a t t h e imersed end sf t h e s e c t i o n reverses t h e d i r e c t i o n of t h e beam by t o t a l i n t e r n a l r e f l e c t i o n , A s l o t of a p p r o p r i a t e l e n g t h , c u t t o i n t e r c e p t one o f these l i g h t b e a m , c o n t a i n s t h e f l u i d and p r o v i d e s a n i n v a r i a n t p a t h l e n g t h f o r a b s o r p t i o m e t r i c measurements. T h i s device w a s conceived when i t w a s found t h a t s i n g l e c r y s t a l lanthanum f l u o r i d e - an o p t i c a l q u a l i t y material a v a i l a b l e i n massive shapes - w a s a s u i t a b l e window material f o r s p e c t r o p h o t o m e t r i c measurements of at l e a s t l i m i t e d d u r a t i o n in f l u o r o b s r a t e c o o l a n t m e l t s . P l a s t i c mockups of such a d e v i c e have been t e s t e d with aqueous systems and found t o g i v e a c c u r a t e absorbance measurements. More r e c e n t l y , s l i g h t l y more complex d e s i g n s have been conceived t h a t w i l l e f f e c t simultaneous measurements of a b s o r p t i o n and s c a t t e r i n g . Composite m o d i f i c a t i o n s will permit use of smaller q u a n t i t i e s of o p t i c a l materials ( s e e Subtask 5.2.1.9, Development of a d i a m n d t i p p e d o p t i c a l probe). Lanthanum f l u o r i d e i s b e i n g o b t a i n e d t o f a b r i c a t e a probe f o r tests i n molten c o o l a n t salts. These tests will p r o v i d e i n f o r m a t i o n f o r g e n e r a l use of t h i s t e c h n i q u e i n c o o l a n t s a l t streams.

....

6-59

6.5.8

Task 5.2.4 E f f e c t s of r a d i a t i o n on o p t i c a l components and s p e c t r a

ri~ Many of t h e i n - l i n e s p e e t r o p h ~ t ~ m e t measurements for a n MSBR w i l l be performed i n t h e p r e s e n c e of i n t e n s e b e t a and g a m a r a d i a t i o n and perhaps moderate n e u t r o n f l u x e s . It w a s demonstrated by measurements of remelted ?BEsamples t h a t meaningful s p e c t r a l i n f o r m a t i o n could be o b t a i n e d f o r h i g h l y r a d i o a c t i v e molten s a l t samples; however, because of unavoidable d e l a y s , t h e a c t i v i t y of t h e s e samples had decayed to a l e v e l at l e a s t two o r d e r s of magnitude below t h a t a n t i c i p a t e d d u r i n g i n - l i n e applieat i o n s . Methods f o r t h e e l i m i n a t i o n of t h e p o s s i b l e i n t e r f e r e n c e from Cherenkov emissions w i l l b e e s t a b l i s h e d f o r t h e s e a p p l i c a t i o n s . The p o s s i b i l i t y t h a t o t h e r o p t i c a l emissions can b e s t i m u l a t e d by t h e i n t e n s e r a d i a t i o n in t h e f u e l w i l l a l s o b e considered. Should such emission be p o s s i b l e i t will b e e v a l u a t e d as a n i n t e r f e r e n c e t o a n a l y t i c a l methods, and t h e n s t u d i e d f u r t h e r as a s e p a r a t e i n v e s t i g a t i o n f o r p o s s i b l e anal y t i c a l u s e f u l n e s s in t h e area of g e n e r a l O K s p e c i f i c fuel c h a r a c t e r i z a t i o n . Measurements w i l l be made of t r a n s i e n t and long-term e f f e c t s of r a d i a t i o n on t h e t r a n s m i s s i o n of diamond windows t h a t w i l l . be used f o r t h e most p r e c i s e measurements (cf Subtask 5.2.1.2) Less r i g s u r o u s measurements w i l l a l s o be made f o r o t h e r proposed o p t i c a l components i n c l u d i n g o t h e r probe and window materials and materials f o r containment windows. Those materials t h a t w i l l b e exposed t o t h e s a l t w i l l be t e s t e d under simultaneous exposure t o b o t h r a d i a t i o n and molten s a l t s . Some of t h e s e s t u d i e s may be c a r r i e d o u t i n c o n j u n c t i o n w i t h tests of i n s u l a t i n g materials for e l e c t r o a n a l y t i c a l measurements. E f f e c t s of r a d i a t i o n on ~ p t i ~ sao lu r c e s and d e t e c t o r s w i l l a l s o be e v a l u a t e d . It is planned t o u s e c o l l i m a t e d beams from t u n a b l e lasers so t h a t t h e s e components can be l o c a t e d o u t s i d e areas of i n t e n s e r a d i a t i o n ; however, c l o s e mechanical coupling of o p t i c a l elements may be r e q u i r e d t o minimize vibration effects. a

The c a p a b i l i t i e s of s p e c t r a l methods f o r measurement of minute samples

will be used t o s t u d y t h e e f f e c t s of r a d i a t i o n OR t h e chemistry of f u e l melts. Such measurements w i l l be needed t o p r e d i c t e f f e c t s ora i n - l i n e a n a l y t i c a l d e t e r m i n a t i o n s by s p e c t r a l and o t h e r t e c h n i q u e s and W51l prov i d e b a s i c chemical i n f o r m a t i o n . I n i t i a l l y , t h e s p e c t r a of small samples t h a t are s p i k e d w i t h r a d i o a c t i v e i s o t o p e s w i l l be measured. Eater a t t e m p t s w i l l b e made t o measure s p e c t r a in molten f u e l i n which r e a l i s t i c f i s s i o n i n g levels are g e n e r a t e d e i t h e r by e x t e r n a l o r i n t e r n a l n e u t r o n BOUPC~S. Neutrons could be g e n e r a t e d i n t e r n a l l y by i n t e r a c t i o n of t h e b e r y l l i u m w i t h high energy a l p h a p a r t i c l e s , OK perhaps by t h e a d d i t i o n of c a l i f o r n i u m . P a r t i c u l a r a t t e n t i o n w i l l b e given t o t h e e f f e c t s on couples t h a t w i l l be involved i n p o t e n t i o m e t r i c measurements w i t h reference electrodes.

6-60

6.6.1

Objective

The o b j e c t i v e of t h i s t a s k i s t o a s s u r e t h a t t h e r e q u i r e d chemical a n a l y s i s methods are available to t h e Program when needed and t o d e v e l o p in-%Fne c h e d c a b methods t h a t w i l l be essential to reactor o p e r a t i o n s . For t h e nation of d i s c r e t e samples the d e f i n i t i o n 5f chemical methods as sds in which t h e sample i s a l t e r e d by a chemical reagent" w i l l b e y extended t o i n c l u d e analytical procedures in which the samples j e c t e d t o analysis by diverse p h y s i c a l t e c h n i q u e s such as X-ray n and fluorescence, emission spectrography, and vari5us spectrephysics approaches. Except f o r unusual circumstances, the a c t u a l p e r f o r mance of s e ~ ~ f analyses ce WIPE not be an objective of this t a s k group. Ratherr,t h e task group w i l l p r o v i d e l i a i s o n between u s e r s of a n a l y t i c a l services and t h e service l a b o r a t o r i e s i n o r d e r t o promote the optiwearw s e i m ~ i o nof methods. b c e p t i o n s w i l l i n c l u d e applications in which etenees may e x i s t w i t h i n the AnaPyticaE C h e m i s t r y Research and Development Group and o c c a s i o n s i n which o n s i t e analysis can be performed more e f f i c i e n t l y by group members. Task Group 5.3 w i l l n o t i n c l u d e measurement performed on remelted samples. Such a p p l i c a t i o n s will b e handled under t h e preceding tasks.

The s e h e d d e f o r work in t h i s task group is shown in Table 6.6.2.

Operating fund I - ~ ~ U ~ K ~ R E Tfor K ~ S t h i s t a s k group are shorn i n Table 6 , 6 - % * l , and c a p i t a l equipment fund requirements a r e shown in Table 6 . 6 . 3 . 2 . 6a 6a 4

Facilities

With t h e e x ~ e p t l i ~sf n l i m i t e d expansion i n t o c o n v e n t i o n a l l a b o r a t o r i e s no need f o r a d d i t i o n a l f a c i l i t i e s i s a n t i c i p a t e d f o r Task Group 5 . 3 activities t h e r , t h e extensive f a c i l i t i e s available a t the Oak Ridge CompPex w i l l be u t i l i z e d . L i m i t e d usage may a l s o b e m d e of f a c i l i t i e s a t the U n i v e r s i t y of Tennessee w i t h which t h e Laboratory rmaintains a c l o s e working rePat~c3nship. s

6.6.5 The need f o r a n a l y s e s of discrete sanples will c o n t i n u e throughout the Program and, indeed, w i l l p e r s i s t even f o r the most completely instrumented o p e r a t i n g r e a c t o r . A wide v a r i e t y of a n a l y t i c a l t e c h n i q u e s have a l r e a d y been a p p l i e d t o samples from the Program.* The s t a t u s of such

gable 6.6.2.

5.3.1

Analysis 5.3.1.1 5.3.1.2 5.3.1.3 5.3.1.4 5.3.1.5 5.3.1.6

5.3.2

In-lfne 5.3.2.1 5.3.2.2 5.3.2.3 5.3.2.4 5.3.2.5 5.3.2.6

Schedule for work in Task Group 5.3 - Analyeis

of discrete samples Bismuth Oxide Coolant cove!r gas eomdensate Tellurim Precise uranium Special methods cbmfca8 methods Salt faow metering Qxide in fuel Reducing power in fud Bismuth tbanspfratisn R@aucing power 0f bismuth a8loys Qxide in coolant

by chemical

methods

Table 6.6.3-l.

5.3.1

5.3.2

5.3.3 Total

Analysis 5.3.1.1 5.3.1.2 5.3.1.3

Qperating

5.3.1.4 5.3.1.5 5.3.1.6

of discrete samples Bismuth Oxide Coolant cover gas candensate Tellurium Precise uranium Special methods

Subtatal

5.3.1

In-line 5.3.2.1 5.3.2.2 5.3.2.3 5.3.2.4 5.3.2.5 5.3.2.6

ehemiea~ methods Salt flow metering Qxide iti fuel Reducing power in fuel Bismuth transpiration Reducing power of bismuth alloys Oxide in coolant

Subtotal

5.3.2

Effects of radiation methods operating

funds for

fund requirements far Task Group 5.3 - Analysis (costs in %.QQQ dolPars)

1975

1976

1 4

5 2

10 1

8 3

6 2

6 PO 5 5

Fiscal

year

by chemical

methods

1977

1978

1979

1980

1981

1982

198%

1984

1985

7 7

9 9

12 I1 23

17 I.4 39.

25 15 40

15 15

20 20

18 5 12

20 6 10

22 6

10 15

16 44

16 26

5 15 20

15 51

8 65

15 75

30 60

40 80

12 47

on chemical Task Group 5.3

40 60

1986

6-63

Capital equipment fund requirements f o r Task Group 5 . 3 Analysis by chemical methods ( C Q S t S i f l 1000 d o l l a r s )

Table 6.6.3.2. -

F i s c a l year

5.3

Miscellaneous i t e m

1975

1976

1977

I978

1979

1980

6-64 methods w i l l b e s u r x y e d at i n t e r v a l s and close l i a i s o n will b e mikpt a i n e d w i t h experimental i n v e s t i g a t o r s so t h a t any r e q u i r e d development work can b e carried stat i n a n t i c i p a t i o n of weeds. Also, a s u r v e u l a n c e of new developments i n t h e technology o f a n a l y t i c a l ebredstry will b e maintained t o uncover approaches that could y e i l d s u p e r i o r o r more economical a n a l y s e s of MSBR samples. Promising advances will b e submitted t o appropriate methodology groups f o r development or', when d e s i r a b l e , w i l l b e a c t i v e l y developed as a p a r t 0 % Subtask 5.3.1.6. Another res p o n s i b i l i t y i n h e r e n t i n t h i s s u b t a s k will be t o p r o v i d e a d i s i n t e r e s t e d t h i r d p a r t y on o c c a s i o n s when a n a l y t i c a l results do n o t a p p e a r c o n s i s t e n t ray cases t h i s a c t i v i t y will be l i m i t e d w i t h experimental operations. I n t o a d v i s o r y a c t i o n s , b u t may i n c l u d e performing the sampling and a n a l y s i s o p e r a t i o n s o r developing new methods. An e s s e n t i a l p a r t of t h i s work will b e t o v a l i d a t e o r improve methods f o r t a k i n g and p r e p a r i n g r e p r e s e n t a t i v e samples f o r a n a l y s i s .

6.6.5.1

Subtask 5 . 3 . l . l

Determination of bismuth

Because of t h e p ~ t e n t i a ldamage t o s t r u c t u r a l materials by trace concentrations of bismuth t r a n s f e r r e d t o t h e reactor via p r o c e s s i n g streams, e x t e n s i v e r e s e a r c h and development s t u d i e s w i l l be carried out ts develop methods of l i m i t i n g such transfer. Nethods of a d e q u a t e s e n s i t i v i t y have a l r e a d y been developed t o s u p p o r t such s t u d i e s . Wn u n a c c e p t a b l e scatter has been experienced b t h e a n a P y t i C d data o b t a i n e d d u r i n g e f f o r t s to measure t h e s o l u b i l i t y of bismuth i n f u e l s a l t s . S i n c e t h e e o n c e n t r a t i o n s measured are below one ppm, t h e e r r o r s c o u l d r e a d i l y have been imtroduced by the e n t r a i n m e n t of p a r t i c d a t e bismuth d u r i n g sampling o r by esntamin a t i o n i n t r o d u c e d d u r i n sample p r e p a r a t i o n and d i s s o l u t i o n . The e n t i r e l i n g and a n a l y s i s sequence will be examined, when such experiments are r e - i n i t i a t e d , t o l o c a t e p o s s i b l e sources o f contamination and t o determine whether some unexpected i n t e ~ f e r e n c ec o u l d have c o n t r i b u t e d to e r r o r s i n t h e a n a l y s i s . Remedial action w i l l be recornended and agpropr2at.e procedures w i l l be developed f o r t h e sampling and a n a l y s i s of fuel s a l t s f o r bismuth d e t e ~ ~ ~ i ~ t t i ~ n .

6 e 6 e 5 . 2 Subtask 5.3.1.2

D e t e m i n a t i o n of oxide

w...

6-65

atmospheres are b e i n g made by the service g r o u p s and experiments have been designed t o d e t e ~ d n ethe magnitude, and source of contanminat%on d u r i n g sample p r e p a r a t i o n and t r a n s f e r to the a n a l y t i c a l a p p a r a t u s . %en these experiments have been completed and c o r r e c t i v e a c tf on has been t a k e n , similar experiments will b e designed t o s t u d y contamination d u r i n g t h e withdrawal s f samples from e x p e r h e n t a l f a c i l i t i e s . An i n v e s t i g a t i o n of p o s s i b l e s e g r e g a t i o n of oxide d u r i n g f r e e z i n g will also be carried o u t , and c r i t e r i a for t h e p u l v e r i z a t i o n r e q u i r e d f o r r e p r e s e n t a t i v e sampling w i l l be estab%ished

6.6.5.3

Subtask 5.3.1.3 I d e n t i f i c a t i o n of condensate from the cover gas o f MaBF4

.im o i l y condensate has been c o l l e c t e d from the c o v e r gas 0 % e n g i n e e r i n g t e s t f a c i l i t i e s f o r t h e e v a l u a t i o n of NaBP4-NaP e u t e c t i c . as a c o o l a n t , Elemental a n a l y s e s o f t h i s condensate a r e c o n s i s t e n t w i t h t h e p r e s e n c e s f hydrolysis p r o d u c t s of BF3s b u t iire n o t d e f i n i t i v e . It has beera shown t h a t t h e c o n d e n s i b l e s p e c i e s i s i n e q u i l i b r i u m with a c t i v e p r o t o n s i n t h e melt, and evidence e x i s t s that t h e material could serve as a v e h i c l e for c o l l e c t i n g tritium t h a t d i f f u s e s i n t o the c ~ o ~ a system.72 nt ~ ~ a e i d e n t i f i c a t i o n s f the i n d i v i d u a l compounds in this condensate i s needed t o assist i n t h e u n d e r s t a n d i n g of t h e chemfstry of p r o t o n a t e d s p e c i e s i n molten NaBF4 and t o d e s i g n experiments t o e v a l u a t e the p o t e n t i a l of Diverse chemical and physical c h i s c o o l a n t s a l t f o r tritium containment methods such as NMR and infrared methods w i l l be used t o e s t a b l i s h the composition of t h e condensate. E f f o r t s w f l l a l s o b e made t o identify its p r e c u r s o r in t h e gas phase u s i n g e i t h e r d i r e c t infrared measurements e c~t r~odm e t r y o r measurement o f the p o s s i b l y w i t h F o ~ r f e ~ - t r a n s fs~p ~ s p e c t r a of m a t r i x - i s o l a t e d condensate. once i d e n t i f i e d , t h e gases and condensed s p e c i e s will be compared w i t h a s y n t h e t i c material of similar p r o p e r t i e s t h a t can b e generated by the r e a c t i o n of boron t r i f l u o r t d e w i t h water. 1% t h e s e materials prove i d e n t i c a l , the s y n t h e t i c p r o d u c t s w i l l be used t o e s t a b l i s h a n a l y t i c a l methods f o r the q u a n t i t a t i v e col%ect i o n o f condensate, i t s in-line measurement, and the conversion of i t s hydrogen contemt to the e l e m e n t a l f o m for isotopic analysis. Methods Plevelsped i n t h e s e s t u d i e s d.11 b e used at the CSTF in s u p p r t of t h e Deuterium I n j e c t i o n Experiment to d e t e r m i n e the p s t e n t i a l of NaBP4 f o r tritium containment. a

4.4.5.4

Subtask 5.3.36.4

Determination of t e l l u r i m

Materials s t u d i e s have i n d i c a t e d that t e l l r p r i ~ mi s , a t b e a s t in p a r t , r e s p o n s i b l e f o r the intergranular c r a c k i n g that was observed i n Haetelloy Ea during o p e r a t i o n of the HSRE* C o n c e n t r a t i o n s of t e l l u r i u m i n the low ppm l?aIlge &fill be present i n f u e l salts to Which taeta%%Urgied.s p e C h ? n s are exposed. Methods will b e developed f o r t h e d e t e m i m t i o n of t e l l u r i u m at the r e q u i r e d c o n c e n t r a t i o n levels. A t o m i c a b s o r p t i o n , perhaps with p r e - c o n c e n t r a t i o n , i s t h e most l i k e l y approach f o r such d e t e r m i n a t i o n s

6-66

6.6.5.5

Subtask 5.3.1.4

P r e c i s e d e t e ~ ~ l i m t of i ~ uranium n

Methods sf h i g h p r e c i s i o n w i l l b e needed to d e t e c t v a r i a t i o n s in t h e c o n c e n t r a t i o n of uranuim i n t h e fuel t h a t c o u l d b e o f s i g n i f i c a n c e to r e a e t o ~o g s e r a t i ~(see ~ Subtask 5.2.1.2). Such methods must be adaptable to emote d e t e r m i n a t i o n s , because of t h e r a d i o a c t i v i t y of t h e samples, and be a c c u r a t e t o b e t t e r t h a n 0.1 p e r c e n t . During the o p e r a t i o n of the MSRE, i t w a s shown t h a t uranuim could b e q u a n t i t a t i v e l y v o l a t i z e d as UFg from 50 gram samples of t h e fuel, and t h e r e s u l t i n g UFg c o u l d b e decont d n a t e d and collected for i s o t o p i c a n a l y s e s t h a t are p e r f o m e d o u t s i d e t h e hot c e l l . It w a s c a l c u l a t e d that an i s o t o p i c d i l u t i o n method c o u l d y i e l d a c c u r a c i e s approaching 0.01 p e r c e n t . The achievement o f such accuracy w o d d r e q u i r e e q u i v a l e n t p r e c i s i o n i n the a d d i t i o n and thorough mixing of a predetermined q u a n t i t y o f a n o t h e r uranium i s o t o p e t o the f u e l sample. Such a n i s ~ t o p i ca d d i t i o n is f e a s i b l e b u t will r e q u i r e Techniques will. be designed to CZX~K~~ care C Z i n hot cell o p e r a t i o n . p r e c i s e l y weigh a f u e l sample, make an isotopic a d d i t l o n , m e l t and hsmgenize t h e sample ( p o s s i b l y w i t h h y d r o f l u o r i n a t i o n ) , and s e p a r a t e a r e p ~ e s e l - n t a t i v esample of t h e i s o t o p i c a l l y d i l u t e d uranuim f o r r a t i o measurements. Equipment t o accomplish these o p e r a t i o n s will be assembled and t e s t e d i n a h o t - c e l l msckup.

6.6.5.6

Subtask 5.3.1.6

Development o f s p e c i a l methods

This t a s k w i l l b e devoted t o t h e ~ e s o l u t i o no f any s p e c i a l p r o b l e m i n t h e sampling and analyses that remain u n r e s o l v e d from previous studies 8% t h a t w i l l arise i n the c o u r s e of r e s e a r c h and development s t u d i e s f o r t h e BKogralTl. One h O W a % p%OblEXil Of t h i s type iS t h e SeparatiOn sf S U f f P c i e n t q u a n t i t t e s of p a r t i c u l a t e matter, i r o n and n i c k e l , from fuel f o r c h a r a c t e r i z a t i o n . The i d e n t i f i c a t t a n of t h e n a t u r e of such material. could assist i t a t h e r dynamic p r e d i c t i o n s of equilibrium c o n d i t i o n s and r e s o l v e anomalies t h a t have been observed earlier i n t h e P r o g r a m

Because o f t h e n a t u r e sf the a p p l i c a t i o n , i n - l i n e a n a l y s i s of s a l t streams by c h e ~ c a methods l w i l l u s u a l l y be l i m i t e d t o t r a n s p i r a t i o n t e c h n i q u e s ; t h a t i s , t h e i n t r o d u c t i o n o f a rea e n t as a d i l u t e s o l u t i o n i n a n i n e r t gas stream followed by measurements on t h e e f f l u e n t gas O K , i n some cases, in the effluent s a l t by t r a n s d u c e r s d e s c r i b e d i n t h e previous t a s k groups. Other methods of r e a g e n t a d d i t i o n , such as i n a s t r e a m of s a l t 8% a bismuth a l l o y , w i l l be c o n s i d e r e d , b u t such approaches a p p e a r cumbersome rnethods will be ~ l ~ s e l y %or h i g k - t e ~ ~ p e r a t ~~r e~ p l i c a t i ~ TYanspiration n. r e l a t e d t o developments i n Task Group 5 . 4 , Analysis of G a s S t r e a m .

k...

6-6 7 6.6-6.1

Subtask 5.3.2.1

Metering of s a l t flows

The chemical methods w i l l , i n g e n e r a l , measure an e x t e n s i v e p r o p e r t y of t h e molten s a l t as o p p ~ s e dt o i n t r i n s i c measurements performed by e l e c t r o chemical o r s p e c t r o p h o t o m e t r i c methods (Task Groups 5.1 and 5.2); t h e r e f o r e , a measurement of t h e q u a n t i t y of salt subjected t o a n a l y s i s i s r e q u i r e d . 'This could b e accomplished by a n a l y z i n g d i s c r e t e samples t h a t are t e m p o r a r i l y i s o l a t e d from t h e streams, b u t t h i s would n o t permit cont i n u o u s measurement which n a y b e r e q u i r e d i n some a p p l i c a t i o n s . Methods w i l l be developed f o r t h e m e t e r i n g of mall flows of molten s a l t , and i t i s e s t i m a t e d t h a t f l o w rates of 2 to 3 d p e r minute w i l l b e optimum f o r many of the a n a l y s e s . Flow m e t e r i n g might be accomplished by p a s s i v e flow elements such as c a p i l l a r i e s o r o r i f i c e s , b u t i n v i e w of t h e uncert a i n t i e s i n w e t t i n g p r o p e r t i e s S € t h e s a l t s , a p o s i t i v e pumping a c t i o n would app-9: more r e l i a b l e . Aqueous mckups of v a r i o u s c o n c e p t u a l des i g n s of s a l t pumps w i l l b e t e s t e d . These w i l l i n c l u d e simple mechanical d e v i c e s , such as bucket l i f t s , a n archimedian pump, and a pump u t i l i z i n g l i q u i d bismuth valves. F i n a l t e s t i n g of workable d e v i c e s will be done i n the Analytical T e s t Facility.

6.6.6.2

Subtask 5.3.2.2

Determination of oxide i n f u e l

A c o n t i n u o u s s u r v e i l l a n c e of ppm c o n c e n t r a t i o n s of o x i d e s in t h e f u e l s a l t of a r e a c t o r may be r e q u i r e d . While i t i s a n t i c i p a t e d t h a t more ....

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convenient methods w i l l be d e v i s e d f o r d e t e r m i n a t i o n of t h e c o n c e n t r a t i o n sf s o l u b l e o x i d e ion (Subtask 5 . l . l . l Q ) , a chemical method would b e needed t o d e t e r m i n e t o t a l o x i d e i n t h e e v e n t t h a t t o l e r a n c e levels a r e exceeded. Work w i l l b e i n i t i a t e d €or a d a p t i n g t h e h y d r o f l u o r i n a t i o n method f o r o x i d e analysis1 t o continuous i n - l h e measurements; t h e e x t e n t t o which t h e n e c e s s a r y development work w i l l b e c a r r i e d o u t w i l l d e p e ~ don t h e s u c c e s s of d e v e l o p i n g a l t e r n a t e o x i d e a n a l y s i s techniques, and d e t e r m i n a t i o n o f t h e n e c e s s i t y f o r continuous oxide a n a l y s i s . Aqueous mockups of a system t o d e l i v e r metered s a l t flows t o a c o u n t e r c u r r e n t h y d r o f l u o r i n a t i o n c o l m w i l l b e t e s t e d . The r e s u l t s o f t h e s e tests w i l l b e used t o p r o v i d e d e s i g n crfteria for t h e A n a l y t i c a l T e s t F a c i l i t y . Experimental i n v e s t i g a t i o n s i n t h i s f a c i l i t y w i l l b e used t o develop a p r a c t i c a l i n - l i n e system, which w i l l then b e used t o monitor o x i d e i n t h e GSTP o r o t h e r a p p r o p r i a t e f a c i l i t i e s . C o n s i d e r a t i o n w i l l also b e given t o t h e measurement of oxygen o r oxygen f l u o r i d e s i n t h e g a s from t h e f l u o r i n a t o r s of t h e p r o c e s s i n g system i n o r d e r to p r o v i d e a n a l t e r n a t e measurement of o x i d e .

6.6.6.3

Subtask 5.3.2.3

Determination of r e d u c i n g power i n f u e l

Reducing power o r reducing n o r m a l i t y , t h e measurement of t h e hydrogen l i b e r a t e d on d i s s o l u t i o n of f u e l samples i n H C l , w a s t h e o r i g i n a l method used t o determine t h e o x i d a t i o n s t a t e o f d i s c r e t e samples. An e q u i v a l e n t 3' d e t e r m i n a t i o n would p r o v i d e i n - l i n e determination together with a U i n f o r m a t i o n on t h e t o t a l q u a n t i t y of p a r t i c u l a t e metals i n t h e f u e l and c o n t r i b u t e i n f o m a t i o n on the redox p o t e n t i a l i n an e x p e r i m e n t a l r e a c t o r .

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The a p p a r a t u s f o r the d e t e r m i n a t i o n of o x i d e c o u l d r e a d i l y b e converted t o i n c o r p o r a t e a reducin power d e f e P d n a t i O n . me S u b s t i t u t i o n O f pPeCioUs m@tal ColIlpOnelats and t h e u s e Of H??-heliUm mixtures i n place O f HP-hydrogen timuPd l e a d t o t h e oxidation 0 % t h e p a r t i c u l a t e metals. A measurement o f hydrogen i n the e f f l u e n t gas would t h e n c o m p l e t e - t h e d e t e m i n a t i a n . Such a p~-ocecEu~e would a l s o p r o d d e a n e f f l u e n t stream of o x i d i z e d fuel t h a t can b e used t o measure t s t d q u a n t i t i e s of i n d i v i d u a l c ~ r ~ ~ s pir o dnu c t s by e l e s t r o a n a l y t i c a l methods (see Sub t a s k 5.1.1.7, DetePdnatiUn sf t o t a l Corrosion p r o d u c t s ) . Rate data f o r t h e estimation of needed c o u n t e r ~ u ~ r e nh ty d ~ = o f l ~ ~ r i n aconditions ti~n will be e s t a b l i s h e d by measurements of the hydro f l u o r i n a t i o n s f i s o l a t e d SZTlIpleS Sf f u e l from t h e 6s'%P. The e x t e n t t Qwhich Work i n t h i s Subtask will be pursued w i l l depend upon a c o n t i n u i n g a n a l y s i s of the n e c e s s i t y of determining f u e l reducing power.

6.6.6.4

Subtask 5 . 3 . 2 . 4

..x.;..> k

Study o f t r a n s p i r a t i o n of bismuth

The i n - l i n e measurement 0 % bismuth i n t h e r e t u r n stream from t h e proeessifag system w i l l r e q u i r e quantitative o x i d a t i o n of e n t r a i n e d bismuth and b i s n t u t h i d e to the t r i v a l e n t s t a t e . A s t u d y w i l l b e made t o deterdsne whether f i n e l y d i v i d e d bismuth can be o x i d i z e d by a c o u n t e r c u r r e n t hydrof l u o r i n a t i o n t e c h n i q u e . E t has been noted t h a t bismuth t r i f l u o r i d e slowly d i s a p p e a r s from r e s e a r c h f u e l m e l t s i n c o n t r a s t t o o t h e r i o n s which a r e q u i t e stable. T h i s phenomenon may reflect t h e volatility of bismuth triflusride under these c o n d i t i o n s , and, i n f a c t , a recent rep o r t shows t h a t s o l i d BiP3 has an a p p r e c i a b l e vapor p r e s s u r e at r e a c t o r temperatures 6 6 S t u d i e s (Sub t a s k 5 1.lo3 ) now i n p r o g r e s s w i l l d e t e r m i n e whether t h e isss sf bismuth is through ~ t -so, t h e aistribution c o e f f i c i e n t between f u e l and cover g a s w i l l b e d e t e m i n e d , and t h e p o s s i b i l i t y o f u s i n g a t r a n s p i r a t i o n method f o r i s o l a t i n g B i P 3 for ~ ~ ~ ~ U K ~ DwI i Cl l X bIe ~ i n v e s t i g a t e d . F i n a l d e f e m i n a t i o n sf the bismuth could b e made w i t h high s e n s i t i v i t y by atomic a b s o r p t i o n , o r p e r h a p s by a c i v a ~ ~ einfra-red d tec~aniques. T ~ U S , a s i n g l e a p p a r a t u s could p r o v i d e gas stream f o r t h e measurement of o x i d e , t o t a l reducing power, and bismuth t r i f l u o r i d e , and a s a l t stream f o r t h e ~ ~ ~ a s u ~ e e r of n e ntotal t c o n c e n t r a t i o n s s f CCX-KQ~~CXI p r o d u c t s and p o s s i b i l y bismuth e

-6.5

Subtask 5.3.2.5 bismuth alloys

Determination of reducing power i n

at p r e s e n t , both t h e r e f e r e n c e and a l t e r n a t e f l o w s h e e t s f o r f u e l procinclude r e d u c t i v e e x t r a c t i o n w i t h P i t k i m - b i s m u t h a l l o y s for t i o n of the rare e a r t h elements. A measurement of t h e t o t a l reducing POW@% o f bismUth strearras based on h y d r o f l u o r i l l a t i o l l Could provide d a t a r e q u i r e d t o m a i n t a i n alloy c o n c e n t r a t i o n s a t optimum levels. In esnjunctisn with o t h e r a n a l y t i c a l techniques, this method c ~ u l dalso be t o measure the c o n c e n t ~ a t i o n(sf the i n d i v i d u a l metals i n t h e a l l o y s and thus d e t e c t u ~ ~ d e s i ~ a accumulation ble of a p ~ t i c u l a rmetal such as i r o n . Pleasrarment sf the hydrogen g e n e r a t e d by t h e h y d r o f l u o r i n a t i o n of

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a s m a l l s i d e stream of bismuth a l l ~ y under ~ c o n d i t i o n s a t which n e g l i g i b l e o x i d a t i o n of t h e bismuth i s i n c u r r e d would p r o v i d e a s e n s i t i v e measure of the t o t a l e q u i v a l e n t s o f o x i d i z a b l e a l l o y i n g c o n s t i t u e n t s . Performing the h y d r o f l u o r i n a t i o n in c o n t a c t w i t h a metered stream of p u r i f i e d LiFBel72 would p r o v i d e ;E s a l t stream c o n t a i n i n g p r o p o r t i o n a l c o n c e n t r a t i o n s of t h e a l l o y i n g c o n s t i t u e n t s inc1uding t h o r I y ~ [ ~f,o r measurement by e l e c t r o a n a l y t i c a l o r s p e c t r o p h o t o m e t r i c methods. Basic s t u d i e s will b e p e ~ f ~ m et od d e t e r m i n e t h e c o n d i t i o n s under which p u r e bismuth, i n c o n t a c t with EW-BeF2, can b e c o n t a c t e d w i t h EIP in an h e r t gas w i t h o u t g e n e r a t i n g u n a c c e p t a b l e q u a n t i t i e s of hydrogen. If such c o n d i t i o n s cannot b e e s t a b l i s h e d , trace a d d i t i o n s of hydrogen w i l l b e i n c o r p o r a t e d i n t o t h e s p a r g e g a s t o determine whether t h e o x i d a t i o n of bismuth c a n b e suppressed w i t h o u t compromising t h e measurement of hydrogen g e n e r a t e d by t h e o x i d a t i o n of a l l o y i n g c o n s t i t u e n t s Oxidative h y d r o f l u o r i n a t i o n of r e p r e s e n t a t i v e metals from bismuth a l l o y s w i l l t h e n be studPed u s i n g t h e b e s t c o ~ ~ t p ~ ogas ~ ~ ims iex t u r e as a t r a n s p i r a t i o n r e a g e n t . Much of t h i s basic information w i l l result from o t h e r research and development a c t i v i t i e s of t h e Program. The b a s i c d a t a w i l l b e used t o d e s i g n e x p e r b e n t s t o demonstrate t h e f e a s i b i l i t y o f t h e approach and to e s t a b l i s h i t s c a p a b i l i t i e s and l i t n i t a t i o n s for i n - l i n e measurement. T h i s w i l l probably r e q u i r e t h e c o n s t r u c tion of a modest f a c i l i t y u t i l i z i n g g r a v i t y - f e d streams. The e x t e n t t o which work i n this s u b t a s k will be pursued w i l l depend on t h e s u c c e s s i n developing s i m p l e r a l t e r n a t e a n a l y s i s t e c h n i q u e s .

6.6,6.6

Subtask 5.3.2.6

Determination o f o x i d e i n c o o l a n t s a l t s

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The r o l e of o x i d e i n t h e p r e s e n t NaBF4-NaP c o o l a n t s a l t i s n o t y e t fully understood. The o x i d e t o l e r a n c e i s a p p a r e n t l y q u i t e h i g h ; c o n c e n t r a t i o n s i n e x c e s s of 2888 ppw have been measured i n f i l t e r e d samples from r e s e a r c h m e l t s t o which o x i d e h a s been d e l t b e r a t e l y added. Also, i t has been suggestedG4 t h a t s u b s t a n t i a l c o n c e n t r a t i o n s of o x i d e can exert a benign effect by CQntPibuting to t h e s e q u e s t e r i n g o f t r i t i m t h a t d i f f u s e s from t h e primary system. It i s , t h e r e f o r e , n o t c e r t a i n t h a t a n i n - l i n e method for o x i d e i n fluoroborates w i l l b e e s s e n t i a l t o r e a c t o r o p e r a t i o n s . However, an in-line method might be more e s o n o d c a l En t h e l o n g r u n because induced a c t i v i t y i n t h e samples w i l l probably be s u f f i c i e n t t o r e q u i r e expensive hot-cell a n a l y s e s of d i s c r e t e samples. .Also, much o f t h e basic s t u d i e s needed for an i n - l i n e method w o d d b e a p p l i c a b l e t o a n a l y s i s o f i n d i v i d u a l samples e A h y d r o f l u o r i n a t i o n method dll be t h e f i r s t c h o i c e for t e s t i n g . The initial i n v e s t i g a t i o n w i l l have t o b e i n d i r e c t because BP3 En the e f f l u e n t g a s w i l l i n t e r f e r e w i t h e s t a b l i s h e d methods f o r measurement of t h e ''water'' Accordingly, melts congenerated by t h e hydrof l u o r i m t i o n of o x i d e e

taining readily measurable cancentrations of oxide w i l l be subjected to h y d r o f l u o r i n a t i o n by MF i n a stream of helium t h a t c o n t a i n s a n e q u i l i b rim c o n c e n t r a t i o n of BP3. E s t i m a t i o n of r e a c t i o n rates w i l l b e made by

6-78

measuring t h e d e c r e a s e i n o x i d e c o n c e n t r a t i o n by t h e Kf3rFb method. (N.B It is n o t , at present, c o n s i d e r e d p r a c t i c a l to a d a p t the versatile mPF4 method to t h e a n a l y s P s of h i g h l y r a d i o a c t i v e MSBR samples. To a v o i d contamination durfng t r a n s f e r , i t w o d d b e n e c e s s a r y t o p e r f o m the T h i s concept w a s exmeasurement w i t h i n an i n e r t atmosphere h a t - c e l l . a d n e d d u r i n g the deVelOpHnent O f t h e a n a l y t i c a l cht3Rf.StPy program f o r t h e MSRE and f a u ~ dt o be e x o r b i t a n t l y expensive and s u b j e c t t o p o t e n t i a l . s a f e t y h a z a r d s ) . I f t h e r a t e of h y d r o f l u o r i n a t i o n of oxides proves too l o w f o r a n a l y t i c a l a p p l i c a t i o n s , s t r o n g e r o x i d a n t s , such as f l u o r o c a r b o n s , w i l l be t e s t e d in a similar manner. When a n e f f e c t i v e r e a c t a n t i s d i s covered, methods w i l l b e developed f o r t h e measurement of oxygen-bearing p r o d u c t s i n the t r a n s p i r a t i o n e f f l u e n t umder Task Group 5 . 4 . In the case of f l u o r o c a r b o n o x i d a t i o n , i n f r a r e d t e c h n i q u e s w i l l b e t e s t e d for the d e t e r m i n a t i o n o f expected c o n s t i t u e n t s such as CO and COF2. For h y d r o f l u o r i n a t i o n e f f l u e n t s , methods developed under Subtask 5 . 4 . 3 . 3 w i l l probably b e a p p l i c a b l e because t h e oxygen i s expected t o be i n c o r p o r a t e d i n the p r o t o m t e d s p e c i e s . Data from t h e s e s t u d i e s will be used t o desFgn a c o u n t e r ~ u r r e n tt r a n s p i r a t i o n system t h a t will b e f u n c t i o n a l l y s i m i l a r t o t h a t used for t h e measurement of oxide i n fuel. T h i s system w i l l be t e s t e d i n t h e AmaPytical T e s t F a c i l i t y a f t e r f u e l tests are completed or by using salt streams f r o m t h e CSTP. 6.6.7.

Task 5 . 3 . 3

G.2

Effects o f r a d i a t i o n on c h m i c a l methods

It i s n o t a n t i c i p a t e d t h a t s i g n i f i c a n t p r o b l e m w i l l b e encountered i n t h e use of chemical methods for t h e analysis of d i s c r e t e samples. The i n t e n s i t y of r a d i a t i o n experienced i n such measurements w i l l i n g e n e r a l b e reduced t o T S ~ B Kt ~o l e r a b l e levels by t h e u s e of small. o r d i l u t e d samples and by t h e decay that will o c c u r d u r i n g t r a n s f e r t o h o t c e l l s . I n t h e analysis of FEE3 samples no d e g r a d a t i o n of p r e c i s i o n and a c c u r a c y w a s observed t h a t could not b e a t t r i b u t e d t o problems of remote h a n d l i n g . New technology i n remote a n a l y s i s w i l l b e i n c o r p o r a t e d a s i t i s a v a i l a b l e i n t o t h e a l r e a d y developed methods f o r these r a d i o a c t i v e samples, Any a d d i t i o n a l developments w i l l be based on e s t a b l i s h e d p r i n c i p l e s t o l i m i t r a d i a t i o n e f f e c t s and t h e new methods w i l l b e v e r i f i e d by s t a n d a r d addition tech~ques e

For i n - l i n e chemical rraethods, which w i l l u s u a l l y b e based on t r a n s p i r a t i o n t e c h n i q u e s , the g a s ~ u sr e a c t a n t s and p r o d u c t s will b e s u b j e c t e d t o a t least t r a n s i t o r y expasure t o i n t e n s e r a d i a t i o n . It i s planned whenever p o s s i b l e t o conduct t h e r a c t a n t s t o a n a l y t i c a l t r a n s d u c e r s t h a t w i l l b e located o u t s i d e t h e area of h i g h e s t r a d i a t i o n i n t e n s i t y . This may not be p o s s i b l e i n t h e case of p r o d u c t s whose a b s o r p t i o n i n g a s l i n e s would Even momentary exposure impose p r o h i b i t i v e t i m e l a g s on t h e measurement. t o t h e radiation f i e l d s c o u l d c a u s e s u f f i c i e n t r a d i o l y s i s of t h e r e a c t a n t s and p r o d u c t s t o c o m p r o d s e t h e a n a l y t i c a l measurements; a l s o , t h e t r a n s p i r a t i o n stream c ~ d cda r r y f i s s i o n p r o d u c t g a s e s and p a r t i c u l a t e r a d i o active matter ta t h e a n a l y t i c a l t r a n s d u c e r s . In. cases where e s t a b l i s h e d G v a l u e s are a v a i l a b l e , t h e e f f e c t s of r a d i o l y s i s will b e e s t i m a t e d . If r a d i o l y s i s e f f e c t s are umcceptable, corrective measures w i l l b e taken.

.... ....

6-71

A n a l y t i c a l t r a n s d u c e r s w i l l be modified t o e l i m i n a t e materials t h a t are known t o b e s e n s i t i v e t o r a d i a t i o n . Models of t h e a n a l y t i c a l d e v i c e s w i l l b e t e s t e d under simulated exposures t h a t w i l l i n d u d e t h e t r a n s p i r a t i o n of spiked s a l t samples and t h e a d d i t i o n of f i s s i o n p r o d u c t g a s e s t o t h e t r a n s p i r a t i o n streams. More r e a l i s t i c t e s t i n g w i l l b e c a r r i e d o u t under i n - p i l e c o n d i t i o n s i f o t h e r a c t i v i t i e s of t h e program present. an o p p o r t u n i t y . 6.7

TASK GROUP 5.4

ANALYSIS OF GAS STIEAMS

6 7 1 Q b jeetive

The o b j e c t i v e of t h i s t a s k i s t o a s s u r e t h a t g a s a n a l y s i s methods w i l l b e a v a i l a b l e when needed f o r r e a c t o r a p p l i c a t i o n s and f o r t h e r e s e a r c h and development s t u d i e s of t h e program. Needed d e t e r m i n a t i o n s w i l l i n c l u d e atmospheric contaminants, H2, HF, F2, UP69 f i s s i o n product g a s e s , BP3 and i t s hydrolysis p r o d u c t s , and t r i t i u m . A s i n t h e p r e v i o u s task group (Analysis by Chemical Methods) t h i s a c t i v i t y w i l l n o t b e of a p ~ e d o m i n a n t l y i n n o v a t i v e n a t u r e . Many commercial i n s t r u m e n t s are a v a i l a b l e that can b e used d i r e c t l y o r w i t h m o d i f i c a t i o n s f o r t h e s e d e t e r m i n a t i o n s . It i s a n t i c i p a t e d t h a t improved i n s t r u m e n t a t i o n w i l l become a v a i l a b l e as a result of p o l l u t i o n c o n t r o l developments. To a c h i e v e t h i s o b j e c t i v e i t w i l l be n e c e s s a r y t o m a i n t a i n a s u r v e i l l a n c e of developments i n the gas a n a l y s i s f i e l d s o t h a t a p p r o p r i a t e i n s t r u m e n t a t i o n c a n be r e c s m e n d e d . Whenever p o s s i b l e , equipment t h a t can u l t i m a t e l y b e a d a p t e d to MSBW a p p l i c a t i o n s w i l l be recornended f o r r e s e a r c h and development a c t i v i t i e s of t h e Program. T h i s w i l l p r o v i d e p r a c t i c a l e x p e r i e n c e and l i m i t evalu a t i o n of a l t e r n a t e equipment. 6.7.2

Schedule

The s c h e d u l e f o p work i n t h i s t a s k i s shown in Table 6.7.2. 6.7.3

Funding

Operating f m d requirements f o r t h i s t a s k group are shown i n Table 6 . 7 . 3 . 1 , and c a p i t a l equipment requirements are shown i n Table 6 . 7 . 3 . 2 .

6.7.4

Facilities

No u n u s u a l f a c i l i t i e s will be r e q u i r e d f o r t h i s a c t i v i t y s i n c e t h e v a r i o u s Program f a c i l i t i e s w i l l g e n e r a t e gas streams f o r r e a l i s t i c t e s t i n g .

Tab%e 6.7.2.

5.4.1

AnaByeia 5.4.1.1 5.4.1.2

of fuel cover gas Gas chrornsatographic methods In-line mass spectrometric m?tl¶cd5

5.4.1.3

Specific monitors

5.4 e 2

Analysis 5.4.2.1 5.4.2.2 5.4.2.3 5.4.2.4

of process gas UF6 BF Fp H2-HF mixtures

5.4.3

Analysis 5.4.3.1 5.4.3.2 5.4.3.3

of coohmt cover gas Hsotopes of hydragen Hydrcpgenow comp~pamnds Distribution of hydrogen iSOtOpeS In-line spectrametric methods

5.4.3.4 5.4.4

Schedule

Effects of equipment

radiation

constituent streams

on gas analysis

for

work

in Taab

Group

5.4 -Analysis

gas

streams

Table

6.7.3.1.

Qperating

fund

requirements for Task Group (costs in 1000 dollars)

5.4

-~-

5.4.1

Analysis 5.4.1.1 5.4.1.2 5.4.1.3

of fuel cover gas Gas chromatographic methods h-line mass spectrametric Specific conaitutent monitors

1975

5.4.2

5.4.3

5.4.1

Analysis 5.4.2.1 5.4.2.2 5.4..2.3 5.4.2.4

Subtotal

5.4.2

Analysis 5.4.3.1 5.4.3.2 5.4.3.3

of coolant cover gas Isotopes of hydrogen Hydrogenous compounds Distribution of hydrogen isatopes In-line mass spectrametric methods

5.4.3.4 Subtotal 5.4.4 Total

process

operating

year 1981

1982

1983

1984

1979

3.980

5 5

la 10

15 12

9 1.5

9 36

12 36

14 31.

15 15

1.5 -15

10 10

15 5 5 5 30

10 5 5

5 5

10 PO 5 5 30

9 60

20 65

2s 70

30 60

40 -.. 60

1985

gas streams

5.4.3

for

Fiscal 1978

BF P2 Hz-HF mixture5

funds

gas streams

1977

UF6

Effects of radiation equipment

1976

Subtotal

-Analysis

6 6

8 6

5 17

9 9

12 12

on gas analysis Task

Group

5.4

40 40

1986

Table

6a7.3.2.

Capital

equipment fund requirements Analysis of gas stream (costs in 1000 dollars)

5.4

Miscellaneaw

items

5.4

Prototype

gas chromtagraph

5.4

Quadrapole

mass

spectrometer

5.4 On-line coquter Tatal capital equipment funds for Task

Group

5.4

Task

Group

5.4

2.5

30 -

6-75 6.7.5

Task 5.4.1

A n a l y s i s of f u e l cover gas

P u r i f i e d i n e r t gas w i l l be used t o p r o t e c t b o t h t h e c o o l a n t and f u e l from exposure t o a t m s p h e r i c c o n s t i t u e n t s and t o remove f i s s i o n produet g a s e s from t h e f u e l i n an MSR. Both t h e p u r i f i c a t i o n and a n a l y s i s o f helium were s u c c e s s f u l l y performed a t t h e MSRE and no s i g n i f i c a n t anal y t i c a l development i s a n t i c i p a t e d f o r t h e s e o p e r a t i o n s . The det@rmimt i o n of r e s i d u a l atmospheric g a s e s , g a s e s desorbed from t h e g r a p h i t e moderator, tritium, and p o s s i b l y t h e i s o t o p i c composition of f i s s i o n g a s e s i n t h e o f f - g a s from t h e f u e l system w i l l be r e q u i r e d . S u i t a b l e commercial a n a l y z e r s e x i s t f o r t h e s e d e t e r m i n a t i o n s b u t m y n o t b e u n i v e r s a l l y a p p l i c a b l e because of t h e r a d i o a c t i v i t y i n t h e gas stream. Limited i n - l i n e methods were a p p l i e d t o f u e l off-gas d u r i n g t h e MSRE development and o p e r a t i o n . A g a s chromatograph t h a t u t i l i z e d a helium break-down d e t e c t o r s e n s i t i v e t o sub-ppm c o n c e n t r a t i o n s o f i n o r g a n i c gases was s u c c e s s f u l l y a p p l i e d to t h e a n a l y s i s of off-gas flpo~li n - p i l e fuel c a p s u l e s .48 N o evidence of r a d i a t i o n i n t e r f e r e n c e w a s encountered b u t t h e i n s t r u m e n t i s n o t expected t o b e r e l i a b l e f o r long tern usage. Simple d e v i c e s i n v o l v i n g thermal c o n d u c t i v i t y c e l l s were used to d e t e r mine t h e g e n e r a l p u r i t y and hydrocarbon c o n t e n t of cover gas from the MSRE Methods f o r c r y o g e n i c a l l y c o l l e c t i n g f i s s i o n p r o d u c t g a s e s f o r i s o t o p i c measurement w e r e developed. T r i t i u m w a s a l s o c o l l e c t e d for c o u n t i n g o u t s i d e t h e ~ e a ~ t area. o r me d e v i c e s u s e d for t h e s e measurements are n o t c o n s i d e r e d adequate i n both s e n s i t i v i t y and long-term r a d i a t i o n s t a b i l i t y f o r r e a c t o r a p p l i c a t i o n s and h p r o v e d d e v i c e s w i l l be developed d u r i n g t h e c o u r s e of t h e Program t o m e e t r e a c t o r r e q u i r e ragnts e

6.9.5.1

.... ....

Subtask 5.4.1.1

Development of gas chromatographic methods

G a s chromatography i s one of t h e more v e r s a t i l e tools f o r i n - l i n e gas a n a l y s i s . However, t h e more sensitive d e t e c t o r s g e n e r a l l y u t i l i z e i o n i z a t i o n phenomena and w i l l t h u s be s u b j e c t to severe i n t e r f e r e n c e s a t t h e a n t i c i p a t e d levels of r a d i a t i o n . One s o l u t i o n is to c o n c e n t r a t e t h e i m p u r i t i e s by cryogenic t r a p p i n g and u t i l i z e thermal c o n d u c t i v i t y c e l l d e t e c t o r s . This s o l u t i o n , however, would d e c r e a s e t h e frequency of a n a l y s e s and r e q u i r e t h e u s e of l i q u i d n i t r o g e n i n i n t e n s e r a d i a t i o n f i e l d s . Therefore, a search f o r more s e n s i t i v e d e t e c t o r s which are n o t a f f e c t e d by r a d i a t i o n w i l l c o n t i n u e . E f f o r t s w i l l b e made to d i s c o v e r t h e r e a s o n f o r t h e s p o r a d i c u n s t a b l e r e s p o n s e of t h e helium break-down d e t e c t o r , and m o d i f i c a t i o n s ~f an u l t r a s o n i c d e t e c t o r w i l l b e made to eliminate materials t h a t are s u b j e c t t o r a d i a t i o n damage. T h i s l a t t e r d e v i c e could a l s o serve as an improved katharometer i n i n s t r u m e n t s f o r t h e measurement of s p e c i f i c c o n s t i t u e n t s o r groups of c o n s t i t u e n t s i n Gas chromatographic sampling valves are a l s o g e n e r a l l y Subtask 5.4.1.3. s u b j e c t t o r a d i a t t o n damage b e c a u s e t h e y c o n t a i n e l a s t o m e r s which would degrade under t h e a n t i c i p a t e d r a d i a t i o n exposure and g e n e r a t e r a d i o x y s i s p r o d u c t s t h a t could i n t e r f e r e w i t h t h e d e t e r m i n a t i o n s . An all-metal p n e u m a t i c a l l y a c t u a t e d sampling valve w a s developed earlier. The valve i s , ~ O W ~ V ~ rKa t, h e r complex and expensive and can e a s i l y m a l f u n c t i o n if

6-94 contaminated by p a r t i c d a t e matter. A navel c ~ n c e p tt h a t u t i l i z e s f l u i d i c c o n t r o l p r i n c i p l e s will be i n v e s t i g a t e d . A chromatograph t h a t u t i l i z e s r a d i a t i o n - r e s i s t a n t components and i n o r g a n i c a b s o r p t i o n columns Will b e d e v d o p e d and tested on t h e Cover gas O f t h e GSTP. Appbh3tiOn to r a d i a t i o n envirsments w i l l be demonstrated s u b s e q u e n t l y i n Task

5.4.4. 6.7.5.2

Subtask 5.4.1.2 methods

Development of i n - l i n e mass s p e c t r o m e t r i c

6.7.5.3 ~ent Ylngr a n a l y t i c a l gas devices have been developed for the ~ l e a s ~ r e ~ of i n d i v i d u a l c o n s t i t u e n t s o r classes of compounds t h a t may b e p r e s e n t i n f u e l cover gas stream. Such devices, which i n c l u d e nondisperaive infrar e d equipment, v a r i o u s forms O f moisture Elonitors, and newly developed solid s t a t e detectors, w i n b e t e s t e d f o r p r o v i a i measurements of blproved s @ € l S i t i V i t y 9 8 back-llrp meth0dSi f o r t h m o s t important determjbnatisns. A p a r t i c u l a r class sf s p e c i f i c i o n monitor i s based on E c o n d u c t i v i t y cell. The measurement i s related ts the change in the thermal c o n d u c t i v i t y o f gas streams that results from the s u b t r a c tion o r a l t e r a t i o n o f a constituent o r class of materials by t r a p p i n g o r by chemical r e a c t i o n . It i s n o t expected t h a t thema% c o n d u c t i v t t y c e l l s w i l l p r o v i d e s u f f i c i e n t s e n s i t i v i t y f o r most of the r e q u i r e d measurements of t h e p~ogralil. I f , however, an u l t r a s o n i c d e t e c t o r can be a d a p t e d t o t h i s -type of measurement, a class of devices that. %soda p r o v i d e continuous ~ e a s U of ~ most ~ ~ o~f nt h e~ c o m t i t u e n t s of i n t e r e s t c o d d b e developed. systems based O n t h i s d e t e c t o r w i l l b e developed w ~ t : kregenerable t r a p s and chemical r e a c t a n t s f a r long t e r m usage.

6.7.6

h - l h e a?LldySeS 5f gas St%ealrmSo f the p r o c e s s h g syS%ew W i b l p r o v i d e a means o f c o n t r o l l i n g c e r t a i n p r o c e s s e s and for i n d i c a t i n g t h e o p e r a t i o n a l s t a t u s of p a r t s sf the system. En gek-ne~al,t h e r e q u i r e d deterwhatism can be performed by e s t a b l i s h e d methods i n d e v i c e s which can b e l o c a t e d o u t s i d e areas of intense radisaetixLty, The ~ e t h o d sthat are t e n t a t i v e l y proposed f o r such a p p l i c a t i o n o u t l i n e d below.

.... .....

d 2 . '

6-7 7

6.7.6.1

Subtask 5.4,2,1

Detemimtion a f UF6

Pieasurewents of UFg would be made i n t h e e f f l u e n t gas frm t h e f u e l r e ~ ~ n ~ t i t u t system. ion Uranium that e s c a p e s hydrogenation c o u l d be t e m p o r a r i l y excluded from t h e reactor s y s t e m and t h u s e f f e c t i v e l y r e d u c e t h e b r e e d i n g r a t i o . The i n t e n s e a b s a r p t i o n of &IF6 i n t h e u l t r a v i o l e t has been used t o measure c o n c e n t r a t i o n s a t t h e p p level. P r a c t i c a l i n v e s t i g a t i o n i n c l u d i n g t h e s e l e c t i o n of compatible window materials w i l l be performed t o develop i n - l i n e i n s t r u m e n t a t i o n f o r t h i s and similar streams. Suck methods will be t e s t e d i n the I n t e g r a t e d P r o c e s s T e s t Facility or in s u p p o r t of earlier development a c t i v i t i e s .

6.7.6.2

Subtask 5.4.2.2

Determination of KP

HP i n v a r y i n g c o n c e n t r a t i o n s w i l l b e p ~ e s e n ti n p r o c e s s i n g streams and p@7%aps i k 9 the COVeP gas Sf t h e f u e l system. DPrKing 0peraf.XbII 0% t h e MSE9 a method w a s developed for t h e d e t e m i n a t i o a of traces o f E?? in t h e f u e l off-gase~.'~ T h i s method w a s based on t h e d e p o l a r i z a t i o n of an aluminum m o d e and u t i l i z e d a n aqueous a b s o r b e r which would probably be u n d e s i r a b l e f o p u s e w i t h r e a c t o r paocessi~gstreams. I n f r a r e d absorpt i o n methods w i l l probably b e s a t i s f a c t o r y f o r t h e measurement of NP i n the overhead sf t h e d i s t i l l a t i o n s e c t i o n of t h e HF r e c y c l e system. I n f r a red methods c o u l d a l s o be a p p l i e d t o t h e d e t e r m i n a t i o n o f HBr and H I i n t h i s stream. Practical i n - l i n e a b s o r p t i o n c e l l s w i l l b e designed and t e s t e d f o r this a p p l i c a t i o n . A method developed t o measure m i c r o ~ ~ ~ o l a r q u a n t i t i e s of HF t h a t are g e n e r a t e d d u r i n g t h e t r a n s p i r a t i o n of f u e l w i t h hydrogenl3 will be used i f more s e n s i t i v e measurements a r e needed.

In-line d e t e r m i n a t i o n s of f l u o r i n e w i l l be u s e f u l i n c ~ ~ ~ t r o l l ti hneg operation of the f l u o r i n a t o r s e c t i o n . The sample input t o t h e a n a l y t i c a l system will be a b i n a r y m i x t u r e ~f f l u o r i n e and an inert gas. The f l u o r i n e can t h e n b e readily d e t e r d n e d w i t h a t h e m a 1 c o n d u c t i v i t y cell6 o r a g a s d e n s i t y b a l a n c e . The p r e c i s i o n s and l i f e t i m e s of such d e v i c e s i n this a p p l i c a t i o n w i l l be e m l m t e d . POP excess f l u o r i n e i n t h e e f f l u e n t , u l t r a v i o l e t a b s o r p t i o n methods will b e used, w i t h p r e c s n v e r s i o n to c h l o r i n e i f a d d i t i o n a l s e n s i t i v i t y is needed. A p r a c t i c a l i n - l i n e c e l l w i l l b e developed f o r t h i s measurement and t h e i n t e r f e r e n c e of other cmponenats of t h i s stream will b e e v a l u a t e d . ... .... ..... .:<Is;.

The i n - l i n e measurement of the composition of the e f f l u e n t gas from t h e fuel r e c o n s t i t u t i o n system w i l l assist i n t h e achievement of more e f f i c i e n t r e d u c t i o n of UF6. The c o n c e n t r a t i o n s o f H2 and HP c a n readily b e measured w i t h thermal c o n d u c t i v i t y cells components t h a t p r o v i d e lorag l i f e t i m e s i n t h i s a p p l i c a t i o n will be s e l e c t e d . e

6-78 6.7.7

Task 5 . 4 . 3

A n a l y s i s of c o o l a n t cover gas

A s w i t h p r e v i o u s tasks r e l a t e d t o coolant s t u d i e s , p r i o r i t y w i l l b e granted t o t h e development of methods f o r the c o o l a n t system i n o r d e r t o p r o u i d e a n a l y t i c a l s u p p o r t f o r t h e Deuterium I n j e c t i o n Experiment. It i s expected t h a t i n - l i n e gas a n a l y t i c a l d e v i c e s i n reactor a p p l i c a t i o n s w i l l n o t be s u b j e c t e d t o s i g n i f i c a n t r a d i a t i o n exposure and, t h e r e f o r e , more c o n v e n t i o n a l i n s u l a t i n g materials such as Teflon c a n b e used. The work i n t h i s task w i l l be a s s o c i a t e d i n i t i a l l y w i t h the m e a s ~ ~ e m e n t of hydrogen and deuterium and l a t e r w i t h tritium. If a f l u o r i d e s a l t i s chosen as a n a l t e r n a t e c o o l a n t t h e methods developed f o r t h e f u e l cover gas (Task. 5.4.1) are expected t o be equally a p p l i c a b l e t o the cover g a s streams 0% t h e c o o l a n t system.

6 * 7 * % . l Subtask 5.4.3.1

Determination of e l e m e n t a l hydrogen i s o t o p e s

I n o r d e r to i n t e r p r e t t h e results of experiments on t h e d i f f u s i o n of deuterium i n t o t h e c o o l a n t s a l t i t will be n e c e s s a r y t o measure B2/D2 r a t i o s and u l t i m a t e l y t o I E E ~ ~ S tUh Pe ~ratios of f r e e t o combined hydrogen and deuterium i n t h e c o v e r g a s streams. A method based on t h e d i f f u s i o n of hydrogen through a heated p a l l a d i m m e ram i n t o a n evacuated system appears to b e t h e m o s t promising approach for t h e measurement of hydrogen i s o t o p e s t h a t a r e p r e s e n t i n t h e cover g a s . When e q u i l i b r i u m i s a t t a i n e d , t h e p a r t i a l p r e s s u r e s sf t h e elemental hydrogen w i l l b e equal on b o t h s i d e s of t h e membrane. The measurement of p r e s s u r e developed w i t h i n t h e evacuated system rhus p r o v i d e s a sensitfve d e t e r m i n a t i o n of t h e concent r a t i o n of hydrogen w i t h i n t h e gas stream. The hydrogen w i l l ~ I S bO e in a s u i t a b l e form f o r t h e measurement of i s o t o p i c r a t i o s . A system has been f a b r i c a t e d which has a r e s i s t a n c e - h e a t e d tube of s i l v e r - p a l l a d i u m allboy as a d i f f u s i o n membrane. Recently, commercial equipment t o accomp l i s h similar s e p a r a t i o n s has become a v a i l a b l e . The s e p a r a t i o ~system ~ o r i t s commercial e q u i v a l e n t will be t e s t e d w i t h s i m u l a t e d cover gas stream t o which s t a n d a r d a d d i t f o m of deuterium and hydrogen have been added. The most successful d e v i c e w i l l be used t o p r o v i d e measurement in t h e off-gas 0 % t h e CSTF. I n i t k l l l y , i s o t o p i c meZiSUrf3tlenfX W i l l b e made on s m p l e a c o l l e c t e d for mass s p e c t r o m e t r i c methods. When a mass s p e c t ~ o ~ ~becomes ter a v a i l a b l e i t w i l l be coupled w i t h t h e d i f f u s i ~ n system t o provide real t i m e d a t a . A swept d i f f u s i o n system w i l l also be developed t o effect i n - l l n e measurement of tritium by i n t e r n a l g a s prop0aPtiQHnal CoUHnting.

6 7 7 2 e

Subtask 5 - 4 . 3 e 2

LY....

b.,.

I d e n t i f i c a t i o n of hydrogen compounds

This a c t i v i t y is c l o s d y a s s o c i a t e d w i t h Subtask 5.3.1.3, I d e n t i f i c a t i o n of condensate from t h e cover gas of NaBPq. It has been d e f i n i t e l y e s t a b l i s h e d t h a t a t least one condensibbe s p e c i e s i s i n e q u i l i b r i u m w i t h a c t i v e p r o t o n s in f l m r o b s r a t e melts. Evidence has a l s o been o b t a i n e d t h a t tritium is p r e s e n t i n muck gl-eater c s n e e n t r a t i o n in t h e condensate t h a n in the s a l t from which Pt w a s d e r i v e d . The i d e n t i f i c a t i o n of t h e hydrogen

..... ~mc.

6-79 compounds in t h e cover gas, which are t e n t a t i v e l y p o s t u l a t e d t o c o n s i s t of h y d r a t e s of boron t r i f l u s r i d e , w i l l b e of c o n s i d e r a b l e v a l u e i n e s t a b l i s h i n g the chemistry of p r o t o n a t e d s p e c i e s i n t h e f l u o r o b s r a t e m e l t s and i n i d e n t i f y i n g a p o s s i b l e mechanism f o r t h e c o l l e c t i o n of t r i t i u m . S i n c e r a t h e r complex e q u i l i b r i a are expected t o be e s t a b l i s h e d i n t h e l i q u i d condensate, d i r e c t measurements i n t h e vapor phase must b e used f o r unambiguous i d e n t i f i c a t i o n . Attempts w i l l b e made t o measure i n f r a r e d a b s o r p t i o n s of t h e v o l a t i l e s p e c i e s a t t h e i r l o w c o n c e n t r a t i o n s i n t h e CSTF cover gas and i n s i m u l a t e d cover gas streams t h a t a r e produced by mixing boron t r i f l u o r i d e and water i n v a r y i n g p r o p o r t i o n s and under d i v e r s e c o n d i t i o n s . Mass s p e c t r o m e t r i c methods w i l l b e used t o examine t h e s e s i m u l a t e d caver g a s e s . M a t r i x - i s o l a t i o n condensation will a l s o b e used t o c o l l e c t samples o f t h e p r o t o n a t e d s p e c i e s f o r i n f r a r e d examination a

6.7.7.3

Subtask 5 . 4 . 3 . 3 Determination o f hydrogen compounds and d i s t r i b u t i o n of isotopes

With d a t a on e l e m e n t a l hydrogen c o n c e n t r a t i o n s from sub t a s k 5 - 4 . 3 -1 t h e measurement of t h e combined hydrogen and deuterium i n t h e CSTP cover gas w i l l p e r r d t t h e c a l c u l a t i o n of r a t i o s o f f r e e ts combined hydrogen and deuterium. These r a t i o s w i l l be needed t o evaluate t h e e f f e c t i v e n e s s of f l u o r s b o r a t e c o o l a n t for t r i t i u m containment. The measurement sf t h e i n c r e a s e i n c o n c e n t r a t i o n of e l e m e n t a l hydrogen t h a t r e s u l t s from the i n - l i n e r e d u c t i o n of cover gas streams w i l l r e f l e c t t h e c o n c e n t r a t i o n of combined hydrogen. Various i n - l i n e r e d u c t a n t s i n c l u d i ~ gNaK and heated magnesium w i l l be t e s t e d f o r q u a n t i t a t i v e l i b e r a t i o n of elemental hydrogen. The hydrogen in t h e reduced streams w i l l b e determined by means of t h e p a l l a d i u m membrane t e c h n i q u e which w i l l a l s o p e r n i t t h e I I E S S U K ~ I U ~ ~of ~ hydrogen-to-deuterium r a t i o s i n t h e hydrogen t h a t i s l i b e r a t e d from t h e s e compounds. The p o s s i b i l i t y of d i s t i n g u i s h i n g between d i f f e r e n t hydrogen compounds by a sequence o f r e a c t i o n s w i t h s e l e c t i v e l y strORg€?r reductants w i l l a l s o be studied. 6.a.7.4

Subtask 5 . 4 . 3 . 4 me t h o ds

Development of i n - l i n e mass s p e c t r o m e t r i c

A h e a t e d i n t e r f a c e f a b r i c a t e d f r o m materials such as n i c k e l that are expected to b e compatible w i t h t h e c o n s t i t u e n t s of t h e CSTF c o v e r g a s w i l l b e used to i n t r o d u c e samples o f t h e g a s t o t h e r e s o l v i n g head of a quadrupole mass s p e c t r o m e t e r . T h i s system w i l l b e used t o t e a t t h e f e a s i b i l i t y of t h e measurement by mass s p e c t r o m e t r y of t h e v a r i o u s cons t i t u e n t s t h a t w e r e measured by s p e c i f i c c o n s t i t u e n t monitors developed i n t h e above subbasks. An a d d i t i o n a l sample i n l e t w i l l be provided to p e r m i t t h e measurement of i s o t o p i c r a t i o s i n t h e hydrogen t h a t i s separ a t e d by t h e p a l l a d i u m membrane a n a l y z e r s e

Task 5.4.4

6.7.8

E f f e c t s of radiation on gas a m l y s i s equipment

Whenever possible the gas analytical equipment w i l l be located outside areas of i n t e n s e radiation to minimize radiation e f f e c t s . En the case of trace element measurements this m y not be possible because of t h e excessive time constants of t h e sample transfer lines. Experimental measurements of time constants far the transfer of simulated gas stream sf all expected types w i l l be made to determine which analyzers must b e located close to the sample s o u r c e . All possible means, such as h e a t e d transfey lines of selected 1066 absorbing materials, will be used to m i n i m i z e the time constants. A s noted in Subtask 5.%s.3.1, the analytical equipment, even in optimum l ~ ~ c a t i ~ can n s , receive significant radiation exposure f r o m fission product gases and particulate radioactive material. This exposure will be m s t s i g n i f i c a n t in the analysis of gases from the f u e l and from t h e flbaoride stream O f t h e f u e l processing SysteITl. u s e of filters to exclude particulate matter and thus simplify maintenance will b e evaluated. Models of analytical equipment that ham bbeen modified to minimize r a a i a t i o n effects w i l l b e t e s t e d under exposure a t appropriate radiation l e v e l s . I n d u s t r i a l radiography sources w i l l b e used t o simulate external exposure and synthetic samples generated by the addition of f i s s i o n product gases will be used to s t u d y t h e effects of internal exposure.

6.8

b..

TASK GROUP 5.5 BY G

EE?,ASUREMENT OF FISSION PRODUCTS MI? PROTAGT'bNPbTM SPECTROMETRY

6.8.1 Bbiective The o b j e c t i v e sf t h i s activity is to develop methods for the direct measurement of t h e d i s t r i b u t i o n of fission products and protactinium by g a m a spectrsmet~y. m e d e p o s i t i o n of c e r t a i n f i s s i o n p r o d u c t s in r e a . ~ t o r components i s Of major interest t o reactor safety and operations. The in-line measurement of certain fission p r ~ d u c t sand protactinium in salt screams would contribute to t h e evaluation of the operation of the p r s c e s s i n g system. A w e a l t h of information w a s o b t a i n e d by gamma scans during the latter periods of XSRE operation. Thlfs task group will be devoted t o t h e fullest p o s s i b l e exploitation of t h i s technique.

6 8 2 e

Schedule

fund requirements f o r this task group are shown in T a b l e al equipment funds wi%% be required in the a m u n t s of $SS,OOO and $38,QQO during PP 1981 and E 1984, respectively, for p u r c h a s e of equipment f o r develsprmaent of gama spectrometry techniques.

k..

5.5.2

In-pile

5.5.3

Equipment

activation for

experiments reactor

app%ications

Table 6.8.3.

Operatimg fund requirements for Task Group 5.5 - Detection arid prstactinftnn by gamma spectrametry (costs in moo dollars)

1979 5.5.1

Evaluation of method 5.1.1.1 Analysis sf MSRE data 5.1.1.2 Evaluation of advanced equipment Subtotal

5.5.1

5.5.2

h-pile

activation

5.5.3

Equipment for

Totall operating

reactor

applications

funds for Task Group

5.5

Fiscal

year

1982

1983

1984

10 50

1980

1981

5 15

10 13

experiments 15

of fission

products

1985

30 30

1986

6-83 6 e 8.4

Facilities

No a d d i t i o n a l f a c i l i t i e s w i l l be r e q u i r e d f o r t h i s a c t i v i t y . E x i s t i n g r e s e a r c h r e a c t o r s and computer c e n t e r s o f t h e Oak Ridge complex w i l l b e used e

6.8.5

.... ,m

.... .f!&

,.&

Task 5.5.1

E v a l u a t i o n of method

A v a r i e t y of f i s s i o n p r o d u c t s w e r e l o c a t e d and i d e n t i f i e d on s u r f a c e s a€ MSRE components by u s i n g a system c ~ m p r i s e dof a l i t h i u m - d r i f t e d germanium d e t e c t o r , a 4096 channel a n a l y s e r , and a l e a d c o l l i m a t o r t o permit examin a t i o n o f mall areas. Much v a l u a b l e q u a n t i t a t i v e and q u a l i t a t i v e i n f o r mation w a s o b t a i n e d on t h e d e p o s i t i o n of f i s s i o n p r o d u c t s on major components ancl op1 t h e d i s t r i b u t i o n of f i s s i o n product g a s e s i n t h e system; b u t some problems in t h e i n t e r p r e t a t i o n of d a t a were encountered, p a r t i c u l a r l y f o r Scans made d u r i n g f d l power o p e r a t i o n . 7 4 These problems were g e n e r a t e d by t h e m u l t i t u d e of o v e r l a p p i n g photspeaks of s h o r t - l i v e d i s o t o p e s f o r which a d e q u a t e energy c h a r a c t e r i z a t i o n s w e r e u n a v a i l a b l e and t h e i n a b i l i t y o f t h e computer program t o resolve t h e l a r g e number of h i g h e r o r d e r ( g r e a t e r than t r i p l e t ) m u l t i p l e t s t h a t were found i n t h e s p e c t r a . S i n c e s i g n i f i c a n t c o n c e n t r a t i o n s of 2 3 3 ~ 2 1w e r e n o t p r e s e n t i n t a does n o t p e r m i t e v a l u a t i o n of t h e potent h e MSRE, t h e e ~ p e ~ i m @ n t daa% t i a l of t h i s t e c h n i q u e f o r i t s measurement. The t e c h n i q u e , i n i t s p r e s e n t s t a t e of development could probably b e used t o measure t h e s i m p l e r cornb i n a t i o n s of i s o t o p e s t h a t w i l l b e p r e s e n t i n some of t h e p r o c e s s i n g streams. With improvements i n r e s o l u t i o n i t c o u l d supply continuous d a t a that would c o n t r i b u t e t o t h e s a f e and e f f i c i e n t o p e r a t i o n of a n WBR.

6.8.5.1

Subtask 5.5.1.1

E v a l u a t i o n of MSFU d a t a

The d a t a o b t a i n e d by g a m s c a n s o f MSRE components w i l l b e r e e v a l u a t e d by basing updated l i b r a r y of i s o t o p i c s p e c t r a and any improved computer programs for t h e r e s o l u t i o n of gamma s p e c t r a t h a t m a y become a v a i l a b l e . Prom p r e d i c t i o n s of d e l a y s i n t r a n s p o r t and from chemical r e s o l u t i o n d a t a t h a t w i l l b e generated by o t h e r r e s e a r c h and development a c t i v i t i e s of t h e Program, t h e abundance o f r a d i o a c t i v e i s o t o p e s w i l l b e computed f o r s i g n i f i c a n t l o c a t i o n s w i t h i n t h e primary and p r o c e s s i n g systems o f a n MSBR. These computations w i l l 9 i n t u r n , b e used to g e n e r a t e s y n t h e t i c s p e c t r a e m i t t e d from t h e s e s e l e c t e d areas ancl p r e d i c t b e n e f i t s t h a t could be expected from i n s t r u m e n t a t i o n of improved r e s o l u t i o n . 6.8.5.2

Subtask 5.5.1.2

E v a l u a t i o n of advanced equipment

Data d e r i v e d from t h e p r e c e d i n g s u b t a s k w i l l b e used t o assess t h e v a l u e to r e a c t o r m o n i t o r i n g of any t e c h n o l o g i c a l advances i n h i g h - r e s o l u t i o n g a m a s p e c t r o m e t r y . The most s u i t a b l e combination of d e t e c t o r s and * analgsers will b e selected and a c q u i r e d f o r experimental a p p l i c a t i o n s

6-84 6.8 -6 Task 5 -5 ‘2

I n - p i l e a c t i v a t i o n experiments

I n - p i l e a c t i v a t i o n experiments w i l l p r o v i d e a v a r i e t y o f i n f o m a t i o n t h a t i s relevant. t o g e n e r a l a p p l i c a t i o n s o f gamma s p e c t r o m e t r y , b u t w i l l b e designed p r i m a r i l y t o assess t h e p o t e n t i a l o f t h e technique f o r t h e ~ ~ ~ o n i t ~of rin p rgo t a c t i n i u m - a d e t e r m i n a t i o n t h a t may t a x t h e c a p a b i l i t i e s of o t h e r i n - l i n e methods. The experiments w i l l , i n g e n e r a l , i n v o l v e t h e measurement of s p e c t r a of s i m u l a t e d f u e l samples a f t e r n e u t r o n i r r a d i a t i o n , b u t may a l s o b e extended t o i n c l u d e the c h a r a c t e r i z a t i o n of e m i s s i o n s O f c r i t i c a l l y i n t e r f e r i n g ShOKt-IiVed isofX3pes t h a t Can be gefzerated by v a r i o u s a v a i l a b l e methods of a c t i v a t i o n . F u e l i r r a d i a t i ~ nexperiments will p r o g r e s s from t h e r e c o r d i n g of gama s c a n s from s m a l l f u e l samples s u b j e c t e d t o brief i r r a d i a t i o n i n an a n a l y t i c a l a c t i v a t i o n f a c i l i t y ( t o measure photopeaks and decay sates s f s h o r t - l i v e d primary f i s s i o n p r o d u c t s ) to long-term i r r a d i a t i o n of c a p s u l e s o f molten o r s o l i d f u e l a t r e a l i s t i c f%umtes i n a r e s e a r c h r e a c t o r ( t o g e n e r a t e measurable levels of 233Pa). If t h e d e t e c t o r system can b e sealed for u n d e m a t e r o p e r a t i o n s , measurements h m e d i a t e l y a f t e r withdrawal can b e made conveniently a t t h e ORB. S u f f i c i e n t measurements will be taken t o d e t e r m i n e the decay p e r i o d ofe nptr o t a c t i n i u m over t h e r a n g e of r e q u i r e d t o permit the m e a s u ~ e ~ ~ ~ required concentrations Supplemental d a t a on t h e r e l a t i v e a f f i n i t y of i n d i v i d u a l f i s s i o n p r o d u c t s can be g a i n e d by performing t h e experiments with capsules f a b r i c a t e d from composite materials o r with c a p s u l e s contaiming m e t a l l u r g i c a l specimens.

gm8.7 Task 5.5.3

S e l e c t i o n and design of equipment f o r reactors

Components of experimental and power r e a c t o r s that will r e q u i r e ~ ~ n t i n u o u s or intermittent g s u r v e i l l a n c e \ g i l l be i d e n t i f i e d through c o n s u l t a t i o n w i t h o t h e r d i s c i p l i n e s sf t h e Program. Prom computations and experimentaE d a t a , s p e c i f i c a t i o n s w i l l b e p r e p a r e d f o r t r a n s d u c e r s f o r measurements a t each o f t h e r e q u i r e d h c a t i s n s . S i n c e r e q u i r e m e n t s of s p a t i a l and photopeak r e s o l u t i o n will v a r y widely, performance s p e c i f i c a t i o n s f o r each measurement w i l l b e determined i n d i v i d u a l l y and w i l l g e n e r a l l y i n v o l v e a compromise of r e s o l u t i o n c a p a b i l i t i e s and p r a c t i c a l c ~ n ~ i d e r a t such i ~ n ~as r e l i a b i l i t y , c o o l a n t requirements and a d a p t a b i l i t y t o remote maintenance. A p p r a i s a l of new developments (Subtask 5.3,1.2) w i l l b e continued t o assure optimum s e l e c t i o n of equipment. Each d e v i c e dll r e q u i r e a complex and expensive i n s t a l l a t i o n ; t h e r e f o r e , t h e u s e o f a single t r a n s d u c e r device f o r i n t e r n i t t e n t m o n i t o r i n g O f d i f f e r e n t components w i l l b e u t i l i z e d when p r a c t i c a l . Gimbal s y s t e m f o r t h e p r e c i s e aiming of t h e massive c o l l i m a t i n g and s h i e l d i n g a s s e m b l i e s w i l l be developed o r s u b m i t t e d t o vendors.

Xf i t proves h p ~ a c t i c a lto measure p r o t a ~ t i n ai t~ essential l o c a t i o n s w i t h t h e decays i n h e r e n t in t r a n s p o r t o f f u e l through t h e p r o c e s s i n g system, t h e concept of d e l a y l i n e s w i l l b e e x p l o r e d . A d e l a y l i n e would c o n s i s t of a p a r a l % d stream o f salt i n which t h e flow i s r e s t r i c t e d to d e l a y t h e a ~ r i ~ of a l f l u i d t o t h e p o i n t of measurement by a p e r i o d sufficient t o p e r m i t decay s f i n t e r f e r i n g i s o t o p e s e

6-85

TASK GRQUP 5.6

6.9

IN-LINE ANALYTICAL TEST FACILITY

6 . 9 1 Objective m

The objective of this activity Is to perfom the nece~sa~)p conceptual design and develop~~e~~t studies f o r the Analytical Test ~acility,to provide the guidance and direction that will b e meeded to design and fabricate the facility which will deliver representative molten-salt streams of control%ed composition to experimental analytical devices, and to utilize the facility to perfect these analytical devices. A s this will be a unique facflity of the Program, efforts w i l l be made to fneorpsrate capabilities that will permit other applications such as b a s i c chemical studies f o r measuring reaction rates in MSBR melts.

The schedule f o r work in t h i s bask group is shown in Table 6.9.2. ..

,.&<A ,.

6.9.4

Task 5.6.1

Conceptual d e s i g n and definition of experimental

This activity w i l l be directed to t h e complete delineation of the capabilities that will be needed to evaluate the performance of various inline analytical transducers in terns of reliability, reproducibility, time c~nstants,and effect of variables such as temperature, flowrate, etc. Presently, it appears that these requirements will be best fulfilled by a small pumped system that will deliver gravity-fed andlor pressurized salt streams to transducers %OK electroanalytical, speetrophoto~tetrie,chemical, and special methods developed in Task Group 5.7, and conform to additional requirements as follows. The s a l t capacity, typically < 28 Kg of fuel, will be adequate to p r o v i d e chemical inertia against gross changes from the introduction sf trace contaminants but small enough t o permit ease in making adjustments i n composition. Materials that contact the salt will be limited to noble metals such coppH and nickel to permit stable OpeKatiOll with relatively O X i d i Z melts. Most of the above and many other features were incorporated in an earlier design75 that utilized a gas lift instead of the proposed mxhanical pump. The considerations leading to the initial deslign w i l l be reviewed to determine what additional. capabilities will be feasible with increased pumping capacity and what may be needed for the IDBK~complete evaluation sf in-line analytical devices. Consultations will be held with other potential users of the facility to dete~wineother needed capabilities

Table

6.9.2.

Schedule

far

work

in Task Group 5.6 - In-line

Analytical Fiscal

Test

Facility

year 1982

5.6.1

Cmceptnal design and definition af experimental prsgram

5.6.2

Development

5.6.3

Final

5.6.4

Fabrication, installation, initial testing

5.6.5

OpsePatiQn

work

far

f-lnal

design

design and

Table

6.9.3.

Operating

fund

requirements for Task Group 5.6 - In-line (costs in 1000 dollars)

1975 5.6.1

Conceptual design and definition of experimental. program

5.6.2

Development

5.6.3

5.6.4

Fabrication, installation, initial testing

work

for

final

design

awilgrn

5.6.5

Operation

Total

operating

funds

1976

1977

Analytical.

Test

Facility

Fiscal

year

1978

1979

1980

1981

1982

1983

5Q 50

60 60

65 65

70 70

40 40

BQ 15

for

and

Task Group 5.6

1984

6-88

that can be incorporated, and with materials, mechanical, and safety specialists to evaluate the practicality and c o s t of various features of t h e facility. Data gained in chese activities will be used to develop the conceptual design f o r a versatile system that will incorporate perfomance, dimensional, and materials specifications. 6.9.5

Task 5.6.2

Development work required f o r final d e s i g n

The testing of transpiration equipment is expected to impose the most: critical requirement f o r salt streams delivered by the Analytical Test Facflity. Nast of these requirements (adequate pressure and space for contactors) will be established by metering systems and countercu~~ent mock up studies performed in Task Group 5 . 3 , Any additional definition of these requirements and those fer the installation of other t y p e s of transducers will be made by additional mock-up studies. Questions relative to the circulating s p t m itself such as mixing times and effects of dead volumes, will be resolved by experiments in glass or plastic models of sections of the system. Data acquired will € o m the basis f o r specifications for the final design o f the facility.

Assistance will be provided as necessary to design engineers in order to expedite the completion of an optimum design. This will include modification of specificati~nsto conform t o practical considerations, and the collection of information f o r t h e preparation of documents required for approval o f construction. 6.9.7

Task 5.6.4

Fabrication, installation and initial testing

As soon as the final design of each subsection of the facility is cornpPeted and approved, materials will be o r d e r e d and fabrication started in order to complete the installation during FY 1979. Initial testing will be perfo~rnediby circulating aqueous solutions o r some other liquid that matches the rheological properties of molten fuel salt. These t e s t s will incliude the calibration of the vsluanes of v a r i o u s vessels and QerifiCati0I-I of flows calculated from d e s i g n specifications. m o w tests Of t h e IllOre CSmpleX tran%dUc€?rSWill be p@rfOlXIed COKLcU9r@latly. 6.9.8

Task 5.6.5

Operation

L I

.... w.:<

6-89 several s a l t stream f o r t h e c o ~ c u r r e ~t e~s t i n g of d i f f e r e n t d e v i c e s . Because many sf t h e tests r e q u i r e t h e a d d i t i o n of c o n s t i t u e n t s that cannot r e a d i l y be removed from t h e s a l t , a c a r e f u l sequencing of experiments w i l l b e r e q u i r e d t o a c h i e v e e f f e c t i v e and economical u t i l i z a t i o n of the f a c i l i t y . Accordingly, long-term s c h e d u l e s w i l l b e d e v i s e d t o p e r f e c t a n a l y t i c a l d e d c e s and accommodate t h e experiments of o t h e r s i n t h e most e f f i c i e n t sequence t h a t i s c o n s i s t e n t w i t h t h e needs of t h e Program. When a p p l i c a t i o n s t o f u e l salts have been e h a w t e d , m o d i f i c a t i o n t o p e r m i t usage w i t h NaF-NaBP4 o r an a l t e r n a t e cooPant wi%E be made, and a s i m i l a r b u t b r i e f e r program w i l l b e s t a r t e d . I t i s n o t expected t h a t t h e same f a c i l i t y can be adapted t o molten l i t h i m c h l o r i d e . Rather, a more modest f a c i l i t y w i l l b e assembled farom ceramic materials, i f necessary a

6.10

TASK GROUP 5.7

6.10.1

Objective

SPECIAL STUDIES

The o b j e c t i v e s o f work i n t h i s t a s k group are f o u r f s l d : f i r s t , to develop and assess t h e v a l u e of methods which, by v i r t u e o f t h e i r advanced n a t u r e , o r m u l t i d i s c i p l i n a r y c h a r a c t e r , cannot b e l o g i c a l l y a s s t g n e d t o any of t h e pPeViOUS task groUpS; .S@CQnd,to pePfQrITl C?XpeleiTE?nts to Which spec i a l f z e d analytical c a p a b i l i t i e s are pecu1iarl.y s u i t e d ; t h i r d , t o automate a n a l y t i c a l methods and t h e a c q u i s i t i o n and p r o c e s s i n g o f d a t a through t h e use of d i g i t a l computers and to apply developed methods i n s u p p o r t o f a c t i v i t i e s o f t h e Program; f o u r t h , t o s e l e c t a r a t i o n a l combination of i n - l i n e and discrete-sample a n a l y t i c a l methods t h a t w i l l assure optimum chemical s u r v e i l l a n c e s f e x p e r i m e n t a l and power r e a c t o r s P r e d i c t e d a c t i v i t i e s i n t h i s task group are d e s c r i b e d i n t h e €o%lowing s u b t a s k s . It i s expected t h a t some expansion of s p e c i a l s t u d i e s , part i c u l a r l y i n t h e areas of t h e f i r s t o b j e c t i v e , w i l l r e s u l t from new t e c h n o l o g i c a l developments i n a n a l y t i c a l c h e m i s t r y . e

The schedule f o r work i n t h i s t a s k group i s s h ~ inn Table 6.10.2.

6.10.3

finding

e r a t i n g fund r e q u i r e m e n t s for work i n t h i s t a s k group are shown i n Table 6.10.3.1, and c a p i t a l equipment fund requirements a r e shown i n Table 6 - EO 3 2. e

6.10.4

Facilities

b a s a d d i t i o n a l f a c i l i t i e s w i l l be r e q u i r e d f o r work i n t h i s task group.

Table 6.10.2.

5.7.1

Special gatlcma 5.7.1.1 5 e7.1.2

electrochemical

invest3.-

x+.dsed techniques Strfpp%i‘lg tQChd.C&b?S

5.7.2

Special opticsI investigations 5.7.2 * 1 Radiolytic oxygen removal 5.7.2.2 Laser raman spectra 5.7.2.3 The-resalved raman 5.7.2.4 Infrared emfasion spectra 5 * 7 * 2 * 5 Wadaoisotogfc light source5 5.7.2.6 Optaacoustic methods

5.7.3

SpectroelecbrQc~gnalcal methods 5.7.3.1 Unusual oxidation states 5.7.3.2 Transient species

5.7,/i

Automated

5.7.5

Evaluatim of analyticd methods for reactor application 5.7.5.1 Fuel system 5.7.5.2 Processing system 5.7.5.3 Coolant system

applications

Sclaedule for WQs%In Task ermp

5.7 - Special. studie5

Table 6.10.3.1.

5.7.1

5.7.2

5.7.3

Special gations 5.7.1.1 5.7.1.2

electrochemical

Subtotal

5.7.1

Special 5.7.2.1 5.7.2.2 5.7.2.3 5.7.2.4 5.7.2.5 5.7.2.6

optical investigations Radiolytic oxygen removal Laser raman spectra Time-resolved raman Infrared emission spectra Radioisotopic light sources Qptoacoustic methods

Subtotal

5.7.2

fund requirements for Task Group 5.7 - Special (costs in 1QOOdoLIars) Fiscal

year 1981

1975

1976

1977

1978

1979

1980

2 2 4

8 7

9 7

10 7 17

12 7 19

BQ ao

7 5 4 4 3

7 7 6 5 4

studies

1982

1983

1984

1985

investi-

Pulsed tecihniques Stri.pplQg techniques

Spectroelectrochemical methods 5.7.3.1 Unusual oxidation states 5.7.3.2 Transient species Subtotal

5.7.3

5.7.4

Automated applications

5.7.5

Evaluation of analytical methods for reactor application 5.7.5.1 Fuel system 5.7.5.2 Processing system 5.7.5.3 Coslant system

Total

Operating

Subtotal

5.7.5

operating

funds for Task Group 5.7

I.5

2 2

1 1

4 4

1 1 2

4 3 7

5 4 9

1.5

12 15 42

20 35

35 5 10 50 90

5Q 20 20 90

5 -80

35 85

60 40 100 __ 125

1986

6-93

The predominant electruchemica% method used t o d a t e f o r m l t e n - s a l t t-eseab-ch and development s t u d i e s , p a r t i c u l a r l y f o r i n - l i n e a p p l i c a t i o n s , has been l i n e a r - s c a n v o l t a m e t r y . Considerable e f f o r t has been devoted t o developing s u i t a b l e instrumentation and e l e c t r o d e combinations f o r these s t u d i e s . Successfu% measurements have been made on e l e c t r s a c t f v e s p e c i e s at t h e ppm c o n c e n t r a t i o n level. Problem areas;, however, s t i l l remain. For example, s u i t a b l e i n s u l a t i n g materials which are compatible with m u l t e n f ~ u u r i d e st s s u ~a l l o w a more p r e c i s e d e f i n i t i o n 0% electrode area and a corresponding inprovenent in the p r e c i s i o n of t h e measurements. The search f o r b e t t e r i n s u l a t o r s w i l l c o n t i n u e . A s i t becomes n e c e s s a r y t o extend t h e e l e c t r o c h e m i c a l methods t o lower c o n c e n t r a t i o n l e v e l s , p a r t i c u l a r l y i n ~ e l a t i o nt o Task 5,2,2 (LiCl analysis), o t h e r electrochemicak t e c h n i q u e s will b e i n v e s t i g a t e d . Among these will be s t r i p p i n g t e c h n i q u e s and p u l s e d techniques, The p r e s e n t i n s t r u m e n t a t i o n can be ~ t i b i z e din many instances for d c stripping a p p l i c a t i o n s ; however, instrumentation f o r pulsed t e c h n i q u e s w i l l have t o be dlevel~ped. Cornm e r C i a l in§tKUIlle€ItZitiQ€l fQr t h e l a t t e r Which 19 s u i t a b l e f o r in-lille molten salt a n a l y s i s i s p r e s e n t l y n o t a v a i l a b l e . Studies will be made t o e s t a b l i s h s u i t a b l e guide l i n e s for t h e f a b r i c a t i o n of suck e l e c t r o chemical i ~ s t b - u r n e n t a t i o n . T h i s w i l l b e folEowed by an e v a l u a t i o n of p r o t o t y p e i n s t r u m e n t s as a p p l i e d t o r e s e a r c h m e l t s and i n - l i n e a p p l i cations

6.10.5.1 **

.... C.BY,

... .... ..... a

........ ~a i i

Subtask 5 . 7 . 1 . 1

The f e a s i b i l i t y Qf appsyfng pulsed techKl%qUeS t o I L l O l t e n Salts has been d e . ~ f s n s t r ~ t t e d . ~~n g t h i s t e c h n i q u e , a s q u a r e wave o r sine wave of ma11 amplitude (millivolts) is s u p e ~ i ~ ~ ~ pon~ sthe e d voltage ramp t h a t i s a p p l i e d to the indicat~rd e c t ~ o d e . The a t t r a c t i v e features of pulsed t e c h n i q u e s are the i n c r e a s e d sensitivity over l i n e a r - s c a n voPtametry, the a b i l i t y t o measure the F a r a d a i c c u r r e n t i n the v i r t u a l absence of charging c u ~ ~ e n and t , p r e s e n a t a t f ~ nof t h e c u r ~ e n ti n the fsm of a symmetrical peak r a t h e r than t h e u s u a l waves o b t a i n e d w i t h Linear-sweep v o l t ~ ~ ~ ~ ~ Pulsed t ~ g rt e.c h n i q u e s a l l o w p r e c i s e measurment of t h e peak h e i g h t and exact l~cations f the peak potential. Instrumentatisn f o r p u l s e d t e c h n i q u e s requires ~ ~ P ~ Qtiming U S and sampling circuits, low-drift a n a l o g r t n ~ ~ ~ ~and ~ r igood e s low-drift differential ampl2fakers. S a t i s f a c t o r y component parts are p ~ e s e n t l ya v a i l a b l e ; howevers comerh s t r u m ~ n t a t f ~t h n a t can be used for research studies and in-line meas~rementsi n molten s a l t s i s not. S t u d i e s w i l l be continued to establish suitable c ~ - i t e ~ f~ aO Kp r o t o t y p e instruments. E v a l u a t i o n of such i n s t r u m e n t s w i l l be m d e on b o t h resealp~tamelts and i n - l i n e s i t u ations i n v o l v i n g f u e l and coolant salts and a l s o for measurements in molten L i C l .

6-94 6.10.5.2

Subtask 5.

The e l e c t r o a n a l y t i c a l s t r i p p i n g method, i n whfch t h e c ~ r r e n trequired to depsshted product is measured, i s a p o ~ e r f u l l technique for i n c r e a s i n g the s e n s i t i v i t y and ssmetimes t h e sellectivity of e l e c t r o a n a l y t i c a l m e a s ~ ~ e ~ ~ nImproved ts. s e n s i t i v i t y r e s u l t s from the f a c t t h a t t h e q u a n t i t y of d e p o s i t e d p r o d u c t , t y p i c a l l y a plated metal, i n c r e a s e s with p l a t i n g rime. Since t h e i n t e g r a t e d c u r r e n t req u i r e d t o o x i d i z e t h e metal i s p r o p o r t F m a l t o t h e e q u i v a l e n t s d e p o s i t e d , much g r e a t e r s i g n a l s than o b t a i n a b l e by d i r e c t v o l t m e t r y can b e produced by a p p l y i n g an a n o d i c p o t e n t i a l scan to an e l e c t r o d e t h a t h a s been plated f 8 P eXte%lded peKfodS. POK d i r e c t C U K P e I I t s t r i p p i n g , t h e most We%%-defined waves and h i g h e s t s e n s i t i v i t i e s are o b t a i n e d when t h e s t r i p p i n g v o l t a g e i s i n c r e a s e d a t reasonably fast ~ a t e s80 t h a t peak-shaped c u r v e s are o b t a i n e d , I n t h e p u l s e s t r i p p i n g mode, all of t h e c o n s i d e r a t i o n s f o r dc s t r i p p i n g t e c h n i q u e s apply. H O W W ~ K , t h e f a r g r e a t e r s e n s i t i v i t y and signal grocc a p a b i l i t y of the puise d e t e c t i o n t e c h n i q u e y i e l d cumiative improvements. Ahtstheaf v a l u a b l e a p p l i c a t i o n of s t r i p p i n g t e c h n i q u e s i s i n the measurement of a p l a t a b l e m e t a l i n t h e p r e s e n c e of anothe~cons t i t u e n t which is ~ ~ d u c et od a s o l u b l e s p e c i e s a t a similar p o t e n t i a l . Because the s o l u b l e s p e c i e s d i f f u s e s from t h e e l e c t r o d e , i t s r e o x i d a t i o n wave does not i n c r e a s e s i g n i f i c a n t l y w i t h p l a t i n g time, and a f t e r extended dep~sitisns the platable i o n c o n t r i b u t e s a dominant signal t o the s t r i p p i n g wave. This t e c h n i q u e has been used t o r e c o r d measurable C ~ K O ~ ~ E U I waves TI in s b u l a t e d M S E f u e l m e l t s t h a t c o n t a i n e d a v o l t a m m e t r i c a l l y overwhelming c o n c e n t r a t i o n of U F ~ . 25 K C ~ % L ~ Ban V~eleetrslytically

It i s e v i d e n t that s t r i p p i n g t e c h n i q u e s w i l l b e needed t o a c h i e v e t h e required s e n s i t i v i t i e s ~ O Kt h e measurement of trace c o n s t i t u e n t s , part i c u l a r l y bismuth a t ppb levels. Enhancement of s e n s i t i v i t y has been demonst~ated i n q u i e s c e n t r e s e a r c h m e l t s that c o n t a i n e d a s i n g l e p l a t a b l e i o n . The a p p l i c a t i o n sf s t r i p p i n g t e c h n i q u e s t o circulating m e l t s i n %oops has been found s u b j e c t t o compPicatisns. A t e l e v a t e d t e m p e r a t u r e s , in6eractisns (tentatively d e s i g n a t e d as a l l o y i n g ) f r e ~ p e n t l g roccur between different d e p o s i t e d metals o r between a d e p o s i t e d m e t a l and t h e noble-metal electrode. A l l o y i n g Can gE3lerate COlIIpleX StPippiHlg p a t t e r n s t h a t cannot, as y e t , b e i n t e r p r e t e d q u a n t i t a t i v e l y . A l s o , even moderate s a l t flow rates can i n c r e a s e p l a t i n g rates s i g n i f i c a n t l y and thus ~ C X D ~ K O * s e q u a n t i t a t i v e ~ ~ ~ e a s ~ ~ e ~C ~~ ~~ ev ne ~t ss .e sl eyl ,e c t i v e alloying can sometimes b e rased ts resalve ~Esselyspaced s t r i p p i n g waves. A CoEIPKehenSiVe PPO r a m of t h e o r e t i c a l and e x p e r i m e n t a l s t u d i e s w i l l b e undertaken t o irecre se the u n d e r s t a n d i n of practical a s p e c t s of s t r i p p i n g methods i n molten f l u o r i d e media, and l a t e r im LiCl. Investbgatisns will i n c l u d e t h e s t u d y of t h e stripping of co-deposited materials from 8 v a r i e t y of e l e c t r o d e materials, t h e use of v i b r a t i n g or r o t a t h n g e l e c t r o d e s t o minimize t h e e f f e c t s of v a r i a t i o n s i n flow, and consultat i o n s w i t h materials s p e c i a l i s t s f o r u n d e r s t a n d i n g of a l l o y i n g phenomena. Pulsed s t r i p p i n t e c h n i q u e s w i l l a l s o b e investigated when a p p r ~ p ~ i a t e i n s t r u m e n t a t i o n i s a v a i l a b l e . The r e s u l t s of these s t u d i e s w i l l b e used t o e%%ectivePy e x p l o i t stripping t e c h n i q u e s f o r t h e fm-line measurement of traces of metallic ions i n MSBB m e l t s . The use of s t r i p p i n g ~netltsods to s t u d y the a l l o y i n g of noble-metal f i s s i o n products with s t r u c t u r a l m e t a l s w i l l be evaluated.

.... e a..,

w.1

6-95 6.10.6

Task 5.7.2

S p e c i a l o p t i c a l methods

The a c t i v i t i e s of t h i s t a s k w i l l be devoted t o u t i l i z i n g t h e -in s i t u c a p a b i l i t i e s of s p e c t r ~ p h o t o ~ i ~ e t methods, ric and o p t i c a l methods i n g e n e r a l , ( s e e Task 5 - 2 . l ) f o r s p e c i a l s t u d i e s on MSBR m e l t s . Included i n t h e s e s t u d i e s w i l l b e a p p l i c a t i o n of e s t a b l i s h e d spectral. methods t o i n v e s t i g a t i o n s f s i g n i f i c a n t chemical q u e a t i s n s i n r a d i o a c t i v e f l u o r i d e m e l t s and t h e assessment of t h e v a l u e of advanced t e c h n i q u e s . A s t h e s e l a t t e r t e c h n i q u e s have had only l i m i t e d a p p l i c a t i o n to f l u o r i d e systems, p r e l i m i n a r y e v a l u a t i o n must be l a r g e l y based on a p p l i c a t i o n s r e p o r t e d i n o t h e r media.

6.10.6.1 & ...,&

....... ..% ..L

,;&

,..w

.:,.

Subtask 5.7.2.1

I n v e s t i g a t i o n of r a d i o l y t i s oxygen removal.

The c o n c e n t r a t i o n of oxide determined i n t h e KbSE f u e l p r i o r t o c r i t i c a l i t y w a s about IO0 ppw; a f t e r c r i t i c a l i t y and throughout t h e rest of MSRE opera t i o n t h e c o ~ ~ e n t ~ a t wi aos n approximately 50 ppm. The h i g h e r i n i t i a l value may w e 1 1 b e a t t r i b u t e d t o e r r o r s i n sampling and a n a l y s i s , but the s t a b l e l e v e l s d u r i n g o e r a t i o n s must be considered as s i g n i f i c a n t . On t h e b a s i s 0f estimates77 of t h e q u a n t i t y of oxygen e n t e r i n g t h e system d u r i n g maintenance, an 86 ppm increase i n o x i d e c o n c e n t r a t i o n would have been expected - a value r e a d i l y d e t e c t a b l e by a n a l y s i s . One h y p o t h e s i s i s t h a t t h e o x i d e w a s converted by a r a d i o l y t i c process e i t h e r t o t h e which r e s u l t e d i n reelement o r gaseous eompoundss such as CO and CO, d u c t i o n of o x i d e C o n c e n t r a t i o n s t~ s t e a d y - s t a t e o r l i m i t i n g levels. Below a c r i t i c a l t e m p e r a t u r e , r a d i o l y t i c f l u o r i n e i s l i b e r a t e d from s o l i d f u e l s . Above t h i s c r i t f c a l b3IIpeKatLUKe the rate of recombination w i t h reduced s p e c i e s i n t h e f u e l exceeds t h a t of r a d i o l y s i s and f l u o r i n e or t h e less e l e c t r o n e g a t i v e oxygen, a h i g h e r c r i t e v o l u t i o n ceases. 7 8 i c a l temperature i s expected, perhaps above t h e r e a c t o r o p e r a t i n g tempera t u r e . s he v e r i f i c a t i o n (and quantifi~ation)of t h i s “ s e l f c l e a n i n g @ ’ h y p o t h e s i s would have f a v o r a b l e i m p l i c a t i o n s t o t h e inherent s t a b i l i t y of molten-salt f u e l s . A s i m p l e best of this hypothesis w i l l b e made by u s i n g i n t e r n a l a l p h a s o u r c e s as a s t a n d - i n f o r i n - r e a c t o r i r r a d i a t i o n . The a p p a r e n t r e l a t i v e s o l u b i l i t y or rates of s o l u t i o n of o x i d e s of i s o t o p e s of widelby d i f f e r i n g s p e c i f i c a c t i v i t i e s w i l l b e measured. Candidate C O ~ ~ Sp aUi r ~s i n c l u d e 244Cm203 and 24%,2839 and 2 3 % w 2 and 242Pu02. I n d i v i d u a l compounds w i l l b e added to oxide-beariag m e l t s of MSRE f u e l s o l v e n t 2n t h e p r e s e n c e and absence of g r a p h i t e . R a d i o l y t i c removal of o x i d e w i l l r e s u l t i n t h e more r a p i d d i s s o l u t i o n sf t h e more a c t i v e csmpsund as evidenced by growth of i t s a b s o r p t i o n spectrbl111, and perhaps changes of i t s spectrum as s o l u b l e sxycomplexes, such as P&+ are converted t o f l u o r i d e s . ~f p o s i t i v e res u l t s are o b t a i n e d , more advanced experiments w i l l b e made i n PaSBR carrier t h e measurement of r a d i o l y s i s salt with g a s - a n a l y t i c a l c a p a b i l i t i e s products.

The i n i t i a l work w i l l b e , i n part, supported by t h e b a s i c a n a l y t i c a l r e s e a r c h program i n transuranirn chemistry and will u t i l i z e Transuranium Research Laboratory f a c i l i t i e s .

... .... ..... , :.a

6-96

6.10 -6.2 The u s e of Rman s p ~ t r o s c o p yfor the s t u d y of pslyatsmic s p e c i e s ia i o n i c melts is 73 B~ using vewintclow~esssi c e l l s , t h i s method h a s been extended t o molten f a _ P a ~ ~ i df o@r ~t h e characterization s f tlae ~ e ~ ion81 4 ~ -in molten L ~ ~ B ~ and P Q other melts, as W e l l a8 the Be P T ~ -i o n and h i g h e r p Q l p e r S 0% b e ~ g r ~ l i U lfluorideS. ll 82 Q u i t e r e c e n t l y 8 2 Rman s p e c t r a of melts c o n t a i n i n g A l P q at temperatUKes

up to 1600°C have been obtained u s i n g a very sLmple experimental apparatus. s p e c t r a of A I F ~ - anti aip63- i o n s were we11 d e f i n e d ; e f f e c t s of changing m e l t composition, trnperature, and content (0.5-2.5 mole %> w e r e investigated. At the p r e s e n t stage of development, the method is r i l y u s e f u l for the c h a r a c t e r i z a t i o n of polyatomic ions a t concent r a t i o n levels as Pow as 0.1 mole % o r less when one of t h e elements involved has a high atomic number. In the MSR Program, R R SpeCtkQSCOpy w i l l b e u s e f u l for the c h a r a c t e r i z a t i o n and analysis of beryllium-, boron--, thorium-, and some uranim-containing s p e c i e s i n f u e l and coolant melts. If the resonance Raman effect i s observed, muck ~ Q W ~concenK trations can b e determined; f o r exam le, i t w a s p o s s i b 1 e 8 ~ t o o b t a i n t h e resonance Raman spectrum of UO$ i o n at csncentrations of <6Q ppm i n 8 a ~ l t e nLie%-KCE. T h e laser R m a m approach is particularly a t t r a c t i v e because it i s the o n l y t e c h n i q u e which o f f e r s pronise f o r t h e in-line d e t e r m i n a t i o n of major constituents of the fuel s s l v e n t , such as BeF2 and ThP4.

A s y s t e m t i c investigation of laser Raman s p e c t r a of f l u o r i d e m e l t C Q ~ positio~sof interest to the MSBR Program will b e u ~ ~ d e r t a k ewni t h aplaasis on quantitative aspect A b s o l u t e accuracy of better t h a n 0.5% should b e f e a s i b l e w i t h modern instrumentation. Analytical p r o c e d u r e s %or t h e -i n situ determination sf total uranium, b e r y l l i u m , thorium, and plutanium w i l l b e developed. This work will b e accompanied by studies of mfnor s o n s t i t . u e n t s , p o s s i b l y some oxygenated species in the c o o l a n t salt and lithium c h l o r i d e , as well as p r o t a c t i n i u m and tellurium i n t h e f u e l salt. %n additiQn to t h e d e V d O p g l e R t Of a n a l y t i c a l pKoC@dU?ZeS, t h e Raman studies w i l l result i n i n c r e a s e d u n d e r s t a n d i n g of the structure s f melts Of iHltE?PeSt t o t h e MSR %PrQgrEUD. a

6.18.6.3 The major remaining p ~ o b in l ~Raman spectroscopy is elinination of f l u o r e s c e n t background. " T h i s problem m y be acute in t h e d e t e c t i o n of 'a weak ~ a m a a nfeature sf G O I Q T ~ ~o r impure samples, and must be solived b e f o r e t h e s i m p l e Rman techniques used %or the characterizations of mjor polyatowis c o n s t i t u e n t s i n m e l t s w i l l become ener a l ly apg Ik a b l e to the d e t e m i n a t i o n of miner constituents, In a p tentially s u c c e s s f u l apprsaeh,85 a p u l s e d laser e x c i t a t i o n S O ~ I K C i~s used t o achieve temporal reSo%ettiOHbbetW@en t h e Short-IiVed 8mLUI s i g n a l (VibKatiOnd l i f @ t h e S on the o r d e r of 18-13 t o IO-'% sec> amd t h e r e l a t i v e l y l o n g - ~ i v e d fluorescenee s i g n a l gflusreseence l i f e t i m e s on the order of to 10-7 see) e Further development work i s n e c e s s a r y b e f o r e t h i s approach i s routinely a an s p e c t r o s c o p i c s t u d i e s . The application

k.2

6-9 3

of t h i s approach t o s t u d i e s of i o n i c m e l t s and o t h e r systems where fluor e s c e n c e i s a s e r i o u s problem w i l l b e i n v e s t i g a t e d . This subfask w i l l be i n i t i a t e d s h o r t l y a f t e r proving the u t i l i t y of Rman s p e ~ t ~ o s c ~ p y f o r t h e q u a n t i t a t i v e d e t e m i n a t f o n of major polyatomic s p e c i e s i n m e l t s of i n t e r e s t t o t h e MSBR Program. I ~ ~ ~ p r o v e m e n i nt s t h e p r e c i s i o n of measurement of m j o r s p e c i e s and i n t h e d e t e c t i o n l i m i t s f o r trace c o n s t i t u e n t s will b e e v a l u a t e d ,

6.10.6.4

.:,.

Subtask 5.7.2.4

Infrared emission s p e c t r a

Determination of i n f r a r e d s p e c t r a i n a d d i t i o n t o t h e Raman s p e c t r a i s r e q u i r e d i n o r d e r t o unde~stand f u l l y t h e i n t e r i o n i c i n t e r a c t i o n s i n i o n i c m e l t s c o n t a i n i n g polyatomic s p e c i e s . I n a d d i t i o n to a more comp l e t e u n d e r s t a n d i n g of t h e s t r u c t u r e s of t h e s e m e l t s , new and improved a n a l y t i c a l procedures f o r c e r t a i n polyatomic s p e c i e s should r e s u l t f ~ o m t h e measurement of i n f r a r e d s p e c t r a of m e l t c o n s t i t u e n t s . Complete c h a r a c t e r i z a t i o n of major p o l y a t ~ m ie~s n s t i t u e n t s of m e l t s by a combinat i o n of Wman and i n f r a r e d measurements could fill a final g a p i n a n a l y t i c a l c a p a b i l i t i e s by providing c % t 6eaSt an i n d i r e c t methad for the e s t i m a t i o n of Lithium and f l u o r i d e c o n c e n t r a t i o n s . ~ e c e n t l y8, 6 i n f r a r e d emission s p e c t r a of molten n i t r a t e s and e ~ ~ o r i c ~ e s were o b t a i n e d w i t h a F o u r i e r t r a n s f o r m s p e c t r o m e t e r (FTS), T h i s approach ~%hlinateS t h e neC.eSS%ty f o r C O n t a c t h g the Ilfdt With ElIl O p t i c a l T!X%teriEll. With t h e PTS, e i t h e r the s p e c t r a c a n be recorded q u i t e r a p i d l y o r the r e s u l t s of many s c a n s can b e r e a d i l y averaged u s i n g an on-line computer which is p a r t of t h e PTS. It i s also p o s s i b l e t o detect d i s s o l v e d species i n l o w c o n c e n t r a t i o n s when t h e y e x M b i t s t r o n g i n f r a r e d bands I n a s p e c t r a l region that i s n o t overlapped by bands of t h e s o l v e n t .

*a,

.... ...... .&<a .

.:.>a

The work w i l l i n v o l v e the development of t e c h n i q u e s s u i t a b l e f o r molten f l u o r i d e s and f l u o r s b o r a t e s . In the l a t t e r case, t h e volatility of eke m e l t w i l l have t o b e taken i n t o account. A f t e r c h a r a c t e r i z a t i o n of species pzesent in melts of interestl t o t h e PER Frogram, the development of analytical procedures for desired major s p e c i e s and the extension of t h i s work t o minor c o n s t i t u e n t s will b e undertaken. Fourier transfsm i n f r a r e d s p e c t r a sf gaseous c o n s t i t u e n t s i n e q u i l i b r i u m w i t h f l u s r o b o r a t e melts will. a l s o b e o b t a i n e d . These r e s u l t s should b e of c o n s i d e r a b l e v a l u e f o r complete u n d e r s t a n d i n g of the c h e m i s t r y of coolant m e l t s .

6.10.6.5

Subtask 5.7.2.5

Radioisotopic l i g h t S O U P C ~ ~

... .... ..... %%3

Optical. r a d i a t i o n generated from r a d i o a c t i v e s o u r c e s can b e ~ E S L S U K C ~w i t h high and p r e d i c t a b l e p r e c i s i o n by photon c o u n t i n g t e c h n i q u e s and the a p p l i c a t i o n of c o u n t i n g statistics. A t h e o r e t i c a l and e x p e r i m e n t a l application of this p r i n c i p l e to iaaalgroved p%bBtometric a n a l y s i s has beem developed u s i n g b e t a - a c t i v a t e d s c i n t i l l a t o r s as l i g h t 86UFces. 87 Recently, i n basic a n a l y t i c a l r e s e a r c h on transuranium c h e m i s t r y , i t w a s d i s c o v e r e d t h a t c r y s t a l s doped w i t h a-emitters can f u n c t i o n as i s o t o p i c l i g h t s o u r c e s a t t e m p e r a t u r e s a t Peast as h i g h its 508°C. Such

6-98

Would be i d e a l l y s u i t e d f o r precise absQKptiometKiC ITE?asuK@m@nts of o p t i c a l r a d i a t i o n of p r e d i c t a b l e i n t e n s i t y that can be generated close t o t h e p o i n t of measurement. N O P ~ Q V ~ L - t, h e s e sources exfaibis sharp peaks i n intensity t h a t would aid i n d i s c r i m i n a t i o n a g a i n s t r a d i a t i o n from t h e m e l t s themselves. Basic r e s e a r c h i n t h e s t u d y of t h e s e high-temperature S Q U ' B T C ~ S , i n p a r t supported by o t h e r a n a l y t i c a l r e s e a r c h pr~g~ippns, will be supplemented by e o n c e p t u a l d e s i g n s and e x p e r i m e n t a l rmsdds Qf devices t o e x p l o i t t h i s phenomenon. A f t e r such d e v i c e s are e v a l u a t e d in a p p l i c a t i Q n s $0 nQn-radiQaC%iVe .StreaIlls of t h e $KQgHaD, t h e effects O f r a d i a t i o n the S B l b r C e s will be evaluated, b o t h f o r th@ g a e r a t i 0 n sf eXtPaneQus m i s s i o n s and f o r damage t o the crystal s t r u c t u r e of t h e pka~sgakors. SOUrCeS

6.10.6.6

Subtask 5.7.2.6

irw

O p t s a c o u s t i s methods

The s p t o a c o u s t i c method is a new and powerful concept f o r gas a n a l y s i s based on t h e f a c t t h a t r a d i a n t energy absorbed by c o n s t i t u e n t s of a gas mixture i s u s u a l l y converted t o thermal energy in the gas phase. During t r a n s m i s s i o n of moduE~itedmQnQChrOmatic r a d i a t i o n , thermal expansions from selective a b s o r p t i o n s by c o n s t i t u e n t s are converted t o sonic s i g n a l s of i n t e n s i t y d i r e c t l y p r o p o r t i o n a l to t h e c o n c e n t r a t i ~ f lof the a b s o r b i n g s p e c i e s . By u s i n g laser s o u r c e s , sensitive lliicrspksnes, and computer p r o c e s s i n g of signals, t h i s technique has beem used f o r a commercial instrument t h a t will automatically measure up to 10 atornospheric contaminants a t ppb levels a t f i v e minute i n t e r v a l s * 8 Methods based 0x1 t h i s p r i n c i p l e would b e of g r e a t value to t h e ~ i ~ l t i c o ~ ~ apn ~ a l ~y s~i se n t of MSBR gas stream, particularly coolant cover gases, b u t would r e q u i r e d e v e l ~ p m e n tsf compatible o p t i c a l and a c o u s t i c a l components. The p o t e n t i a l of applications in t h i s area w i l l be e v a l u a t e d from gas a b s o r p t i o n d a t a g e n e r a t e d by o t h e r s u b t a s k s , Devices f o r i t s a p p l i c a t i o n w i l l b e d e v e l ~ p e c f , e i t h e r as new i n s t r u m e n t s O r as m o d i f i c a t i o n s of c o m e r e i a l l y a v a i l a b l e equipment.

6.lQ.7

Task 5 . 7 . 3

S$gstroeHectrochemicaP s t u d i e s

I n o r d e r to u n d e r s t a n d t h e chemical n a t u r e of m e l t s of interest t o t h e MSBR program i n b o t h a thermodyamic and k h e t i c sense, the n a t u r e , stab i l i t y , and mode of formati~nof v a r i o u s o x i d a t i o n states of s o l u t e s p e c i e s i n t h e s e and related s a l t s nust b e b o r n . E l e c t ~ ~ ~ h e m i s t r y p r o v i d e s a clear and r e l a t i v e l y e f f i c i e n t means to g e n e r a t e v a r i o u s oxidation s t a t e s s f s p e c i e s of i n t e r e s t . T h i s is an i n d i r e c t t e c h n i q u e , however, i n t h a t the i d e n t i t y of t h e p r o d u c t s p e c i e s can only be i n f e r r e d and even t h e n the i n f e r e n c e can only b e mde when t h e e~ectrochemical r e a c t i o ~ ~occur s under c o n d i t i o n s d i c t a t e d by t h e medium of measurement, e.g., voltctmsnetric m e l t l i m i t s , Csnversely, spectral techniques can be Used g o charaC%eXfZe speCi63 t h a t c a n be gellera$ed With h 3 W c u r r e n t e f f i c i e n c y o r i n a t r a n s i e n t state o u t s i d e useful e l e c t r o c h e m i c a l limits. Spectroscopy i s a d i r e c t technique for i d e n t i f y i n g species i n that the t h e o r y is r e a s o n a b l y well advanced so t h a t t h e i d e n t i t y , c o ~ r d i n a t i ~ ~ ~ , and s x i d a t i o n state of amenable d i s s o l v e d s p e c i e s can b e derived fKOm a g i v e n a b s o r p t i o n spectrum. The simultaneous u s e of e l e c t r o c h e m i s t r y and s p e c t ~ o s c o p gi n a given experiment, t h e ~ e f ~ ~can e , y i e l d considerably tisn t h a n either t e c h n i q u e w i l l yield when used a h l e .

c.... .s

ki,

6-99

6.lQ.7.1 & & .

...

... .... , :a

... .... ,.= ,A

.... .:.:.XI

Subtask 5.7.3.1

C h a r a c t e r i z a t i o n of unusual o x i d a t i o n states

A knowledge o f t h e b a s i c chemical c h a r a c t e r i s t i c s of a l l p o s s i b l e oxidat i o n states of many s o l u t e s t h a t w i l l b e p r e s e n t i n f l u o r i d e and c h l o r i d e m e l t s is needed t o p r e d i c t r e a c t i o n s t h a t may o c c u r d u r i n g o p e r a t i o n o f m o l t e n - s a l t r e a c t o r s . S p e c t r a l examination o f e l e c t r o c h e m i c a l l y genera t e d s p e c i e s i n h i g h e r and lower o x i d a t i o n s t a t e s than are thermdynarni c a l l y s t a b l e i n EEBR streams has been demonstrated t o b e a u s e f u l t o o l f o r such s t u d i e s . 8 9 This t e c h n i q u e w i l l b e used t o c h a r a c t e r i z e p o s s i b l e unusual o x i d a t i o n states f o r v a r i o u s t ~ ~ ~ s ii ot n is oi n ~ cluding corrosion p r o d u c t s , l a n t h a n i d e s , t r a n s u r a n i c elements and c e r t a i n n o n m e t a l l i c elements such as i o d i n e and t e l l u r i u m . Measurements of t r a n s u r a n i c elements w i l l a l s o b e supported by a n o t h e r program f o r b a s i c a n a l y t i c a l . r e s e a r c h . When n e c e s s a r y , measurements w i l l b e made i n o t h e r molten s a l t media; e . g . , KEP2s t o o b t a i n s u f f i c i e n t s t a b i l i t y f o r complete s p e c t r a l c h a r a c t e r i z a t i o n . S t u d i e s of t h e l e s s - s t a b l e s p e c i e s i n MSBR compositions w i l l b e performed i n t h e f o l l o w i n g s u b t a s k .

6.10.7.2

Subtask 5.7.3.2

C h a r a c t e r i z a t i o n of t r a n s i e n t s p e c i e s

%his s u b t a s k i s c l o s e l y r e l a t e d t o t h e p r e v i o u s s u b t a s k and t o v a r i o u s tasks a s s o c i a t e d w i t h t h e e f f e c t s of r a d i a t i o n on a n a l y t i c a l methods. En t h e chemistry o f r a d i o a c t i v e MSBR salts many u n s t a b l e and, t h e r e f o r e , t r a n s i e n t s p e c i e s can b e p o s t u l a t e d . In t h e f i s s i o n i n g p r o c e s s very s t r o n g t r a n s i e n t o x i d a n t s are formed, f o r example, a f i s s f s n product n u c l e u s s t r i p p e d of a l a r g e f r a c t i o n o f i t s e l e c t r o n s . Also, t h e number o f v a l e n c e e l e c t r o n s of nonnuclear c o n s t i t u e n t s m y b e a l t e r e d by c o l l i sion with energetic particles. I n r e t u r n i n g t o more s t a b l e o x i d a t i o n s t a t e s t h e s e h i g h l y charged p a r t i c l e s m u s t t r a v e r s e e l e c t r o n configur a t i o n s corresponding t o unusual o x i d a t i o n states. S i n c e l i t t l e i s &mown concerning homogeneous r e a c t i o n rates i n t h e f u e l , i t i s p o s s i b l e t h a t e s p e c i a l l y t h e more d i l u t e c ~ n s t i t u e n t scould b e p r e s e n t a t steady-state i n an oxidation d i s t r i b u t i o n t h a t d i f f e r s significantly Such c s n d i t i ~ n scould result in interferences t o i n - l i n e measurements by i n t r o d u c i n g unexpected s p e c t r a l a b s o r p t i o n s and compromising p o t e n t i o m e t r i c measurements. from equilibrium values.

S p e c t r s e l e c t r o c h e m i c a l methods will be used t o i n v e s t i g a t e p o t e n t i a l i n t e r f e r e n c e s u s i n g t e c h n i q u e s s i m i l a r t o t h o s e a p p l i e d t o t h e chara c t e r i z a t i o n of unusual o x i d a t i o n states. I n t h i s case, t h e s p e c i e s w i l l b e g e n e r a t e d i n a d e l i b e r a t e l y h o s t i l e environment, f o r example, u n s t a b l e o x i d i z e d s p e c i e s would b e g e n e r a t e d i n a reducing m e l t . S p e c t r a l measurements fn t h e immediate v i c i n i t y o f t h e e l e c t r o d e ( u s i n g a c a r e f u l l y focused beam from a t u n a b l e l a s e r ) w i l l b e used t o p r o v i d e estimates of r e a c t i o n rates and p r e d i c t i o n s of p o s s i b l e e f f e c t s on a n a l y t i c a l methods. More s o p h i s t i c a t e d e l e c t r o a n a l y t i c a l approaches (such as t h e r i n g - d i s c e l e c t r o d e system f o r t h e s t u d y o f uns t a b l e s p e c i e s ) w i l l b e coupled w i t h s p e c t r a l systems t o p r o v i d e addit i o n a l measurements. Data o b t a i n e d w i l l be used t o d e s i g n experiments and i n t e r p r e t r e s u l t s f o r Task 5 . 2 . 4 , E f f e c t s o f r a d i a t i o n on o p t i c a l components and s p e c t r a .

6.10.8

Task 5.7.4

Automation and a p p l f c a t f o n of a n a l y t i c a l methods

The value of cumputers t o i n - l i n e measurements has been demonstrated b the a p p l i c a t i o n of a PDP-BI m i n i - c ~ m p ~ tto e ~ t h e measurement of T J ~ + / u ~ r a t i o s in f u e l salt i n a thermal convection loop. Automated 2 4 - h ~ ~ ~ o p e r a t i o n w a s achieved w i t h about a 5-fold h p ~ o v m e n ti n p r e c i s i o n and a more convenient presentation of d a t a . It i s e v i d e n t t h a t comparable improvements can b e achieved by automation and data p r o c e s s i n g o p e r a t i o n s fer a n a l y s e s i n a l l t h e methodology c a t e g o r i e s of t h e Program. P r o g r a m i n g a c t i v i t i e s will b e s t a r t e d on t h e a r r i v a l of a replacement computer which has i n c r e a s e d c a p a c i t y t o c o n t r o l a v a r i e t y of a n a l y t i c a l equipment ow s e v e r a l i n s t a l l a t i o n s . Also i n c l u d e d i n t h e a c t i v i t i e s sf t h i s task w i l l b e t h e a p p l i c a t i o n of e s t a b l i s h e d in-line methods, e i t h e r automated o r manually o p e r a t e d , i n s u p p o ~ tof a c t i v i t i e s of t h e P r o g r m , T h i s w i l l include needed m o d i f i c a t i o n s for special i n s t a l l a t i o n s , but w i l l not i n clude f u r t h e r basic development s t u d i e s performed a t t h e i n s t a l l a t i o n .

6.10.9

E v a l u a t i o n of a n a l y t i c a l methods f o r a n i n t e g r a t e d Task 5.7.5 r e a c t o r s u r v e i l l a n c e system

The p u r p o s e of t h i s a c t i v i t y i s t o develop an overview of r e a c t o r r e q u i r e ments and a n a l y t i c a l c a p a b i l i t i e s t o a s s u r e t h a t all needed methods are e s t a b l i s h e d i n a form t h a t i s c o n s i s t e n t w i t h t h e needs ~ O Kchemical SUFv e i l l a n c e of e x p e r i m e n t a l and power r e a c t o r s . S i m i l a r e v a l u a t i o n s are, of C O U K S ~ , i n f o r m a l l y i n p ~ o g r e s sand w i l l c o n t i n u e d u r i n g the c o u r s e of s e l e c t i o n and development of methods; huwever, t h i s t a s k w i l l i n c o r p o r a t e t h e s y s t e m a t i c p r a c t i c a l assessment of methods a f t e r their c a p a b i l i t i e s and limitations ab-@eStab%iShed. With illput f K O Q l ch63UiCd Research and Development, Reactor S a f e t y , Reactor Design and A n a l y s i s , Reactor Teehnology, and Maintenance, d e c i s i o n s w i l l be made on the need f o r i n - l i n e a n a l y s i s Of t h e Various StreaRIS, t h e degre@ Of ?ZedUndaflCy f o r SUCh analyses, t h e h o t - c e l l ~ e q u i r e m e n t sf o r o t h e r methods, and back-up o r r e f e r e n c e a n a l y s e s . A l s o included w i l l be p r a c t i c a l c o n s i d e r a t i o n s such as the s e l e c t i o n of l o c a t i o n s %OK a n a l y t i c a l devices t h a t are c e ~ ~ i s t e with nt r e q u i r e d response times and maintenance a c c e s s i b i l i t y , m u l t i p l e containment of p e n e t r a t i o n s t o meet s a f e t y r e q u i r e m e n t s , crit e r i a f o r proof t e s t i n g of t h e devices, t h e e s t a b l i s h m e n t of a quality c o n t r o l programs and the interfacing of t h e a u t s m t i c c o n t r o l and outp u t of t h e d e v i c e s w i t h the computer system of t h e r e a c t o r .

The g e n e r a l approach w i l l b e 60 s e l e c t , i n consensus w i t h o t h e r disc i p l i n e s those chemical v a r i a b l e s f o r which r e l i a b l e a n a l y s e s are e s s e n t i a l $5 s a f e K e a c t O r o p e r a t i o n and then recornend d e v i c e s and nethods t h a t w i l l p r o v i d e adequate measurement of these v a r i a b l e s . ~ e n t The i n s t a l l a t i o n of a m u l t i p l i c i t y of d e v i c e s f o r t h e ~ ~ a ~ u r e of a c r i t i c a l v a r i a b l e may be recornended for t e s t reactors. A r e d u c t i o n in redundancy of measurements is expected f o r a d e m o n s t r a t i s n p l a n t a f t e r t h e r e l i a b i l i t y of t h e d e v i c e s h a s been e s t a b l i s h e d i n n u c l e a r OpeKatioTIS i l i a Ei test K e a C t O r .

u.2

A f t e r t h e c r i t i c a l needs s f t h e r e a c t o r are f u l f i l l e d , t h e v a l u e 06 o t h e r i n - l i n e a n a l y t i c a l d e t e r m i n a t i o n s w i l l b e e v a l u a t e d on a c o s t - b e n e f i t b a s i s . Computer models of r e a c t o r systems w i l l b e used t o e s t a b l i s h t h e e f f e c t s o f off-design o p e r a t i o n s on performance parameters such as breedhng r a t i o and i n c r e a s e d f u e l i n v e n t o r y and t o compare this c o s t w i t h t h o s e of i n s t a l l e d a n a l y t i c a l d e v i c e s . It s h o u l d be noted t h a t many o f t h e p r s p o s e d a n a l y t i c a l d e v i c e s can b e modified t o p e r f o m a d d i t i o n a l a n a l y s e s a t nolninal c o s t .

6.10.9.1

Subtask 5.7.5.1

F u e l system

Methods f o r t h e a n a l y s t s of r e a c t o r f u e l are t h e most completely developed; t h e r e f o r e , e v a l u a t i o n f o r t h e primary system w i l l b e s t a r t e d whenever t h e c a p a b i l i t i e s of an adequate f r a c t i o n of t h e c r i t i c a l i n - l i n e methods are demonstrated i n a p p l i c a t i o n t o t h e r e f e r e n c e f u e l . This a c t i v i t y w i l l then serve as a model f o r e v a l u a t i o n of methods f o r t h e o t h e r systems. C r i t i c a l deterrrainations w i l l i n c l u d e o x i d e , T J ~ + / u ~ r a+t i o s o r o t h e r redox p o t e n t i a l measurements, t o t a l uranium, and key c o r r o s i o n p r o d u c t s .

6.10.9.2

Subtask 5.7.5.2

P r o c e s s i n g system

Since the p r o c e s s i n g system is s t i l l s u b j e c t t o e x t e n s i v e development

studies, g e n e r a l e v a l u a t i o n of methods i n t h i s area w i l l have t o b e delayed. Known c r i t i c a l d e t e r m i n a t i o n s i n c l u d e p r o t a c t i n i u m i n t h e s a l t stream f e d t o t h e p r o c e s s i n g p l a n t , and redox p o t e n t i a l , p r o t a c t i n i u m , uranium, bismuth, c o r r o s i o n p r o d u c t s and p o s s i b l y oxFde i n t h e r e t u r n stream. Oxide i n l i t h i u m c h l o r i d e and some i n d i c a t o r e x t r a c t a n t s may l a t e r b e i n c l u d e d as c r i t i c a l d e t e r m i n a t i o n s f o r t h e r a r e - e a r t h s e p a r a t i o n system.

6.PO.9,3

Subtask 5.7.5.3

Coolant system

Evaluation w i l l b e s t a r t e d when methods are e s t a b l i s h e d f o r the coolant t h a t is f i n a l l y s e l e c t e d f o r t h e r e a c t o r . C r i t i c a l d e t e r m i n a t i o n s will i n c l u d e key c o r r o s i o n p r o d u c t s and d e t e r m i n a t i o n s a s s o c i a t e d with t h e d i s t r i b u t i o n of t r i t i u m in the c o o l a n t system.

,.:&

6-182

R. E. Thorna, Chemicaz Aspects of MSKE Operation, OWL--4658 (December

P97l)

R, H, P o w e l l and 0 . Menis, "Separation of F l u o r i d e from Refractory Materials by P y ~ o h y d ~ L IAnaZ. ~ ~ i sChem. ~ ~ ~ 3Q: 1546 (1958).

A. D. Hortsn and P. F. Thomason, "Polarographic Determination of S u l f a t e , " A n a l . Chem. 2%: 1859 (1951)

. ..

&.;.A

e. Goldberg, a. s. Meyer, Jr., and J. 6 . mite, "Determination Of Oxides in F l u s s i d e Salts by High-Temperature Fluorination with Potassium Bromotetraf luoride ," Anal. C k m . 3 2 : 314 (1960) u.:

6. 7.

PP * 12

It. F. A p p l e , Method No. 9021206 (March 16, 1965), ORNL Mas-ke~A m ZyticaZ Mm1uaZ , TID-7015 (SuppH 8 )

6-103

.... , .ZJ

... , .a

.... .:<<*

19.

MSR P ~ o g r a mSemiann. Fpogr. Xept. Aug. 32, 2968, ORBL-4344, p. 3 6 ,

21.

iGB LSrsgxm Semiam, P r s g r . K e p t . Feb. 28,

22.

iG3 Program Semiann. .PPOCJP. Rept.

24.

MSK Prog~amSarniann. P~ogr.R e p t . Aug. 31, 2971, QRNL-4728, p . 7 5 ,

25.

NSR 63rsgrPa.v Semiann. Progr. Kept. Feb. 29, 1992, ORNL-4382, p. 79.

26,

NSR Pplsgrm Semiann. P~ogyr. R e p t . Feb. 28,

27.

MSR Prsgrmn S@rn~ann.Pmgfa. R e p t . Feb. 29, 2972, OWEtL-4782, p . 77.

32.

id%? Program Ssrniunn. P r s g r . K e p t . Feb. 28, 2970, O m - 4 5 4 8 , p. 184.

33.

MSR Progyram Sernianaz. Progas, B e p t . Aug. 1, 2 9 3 0 , QEZML-4622, p. 115.

34.

J. E'. Young and J. C. White, "A High-Temperature Cell Assembly f o r Spectrophotometric Studies in Molten P ~ u a r i d e )s' I A m 2 . Chern. 31: 1832 ( 1 9 5 9 ) .

36.

MSR Program Smiann. Progr. R e p t . Aug. 31, 1965, OFSK-3872, p. 145.

37.

E R Program Semiann. P r o p . Rep&. Aug. 31, 2968, O W - 4 3 4 4 , p. 168.

38.

MSB Prog.ram Semiam. P~sgr. Kept. Aug. 32, 1 9 6 9 , OWN%-4449, p . 161.

39.

MSR Program semi an^. & o p . U.S. Pat. Iw. 3,733,130.

40.

MSR Program Semiann. Progp. Regt. Feb. 28, 4967, OIEah%-4%19, p. 163.

4969, ORNL-4396, p . 208.

Aag. 34, 2968, OWL-4344,

p . 192.

2 9 7 2 , ORNL-4782, p . 135.

~ e g t .aug. 31, 1971, o m - 4 7 2 8 , p. 71,

6-104 41.

4%. 44

ikGB Program Semiann. Progr. aegt. Aug. 31, 1971, o m - 4 7 2 8 , p . 73.

47 48.

49 * 50

55 s 54.

59 m

e. Ting, "Themodynamfc and EleCtKQchemiCal Studies of Niobium f n Molten F l u s r i d e s and Gh1s~oalumiwates,~~ Ph,D. Thesis, University of Tennessee, 1973.

H. W. Jenkins, GI&

6%*

Mamintsv, and D. E. Naaning, "E,M.F. Eaeasurements on t h e Mickel-Nickel (11) Couple in Mobten F l u o r i d e s , If J . EZectroanaZ. Chern. 19: 385 (1968).

6-105

63.

Sybrandt and S. P. Perone, "Computerized Pattern Classification of S t r o n g l y Overlapped Peaks in Stationary E l e c t r o d e Polarography, Anal. Chem. 4 4 : 2331 (1972).

67.

MSR Progrm Semiann. P r o p . Rept. Feb. 29, 2972, 0

68.

R. E. Tkoma, Chemical Aspects of MSRE OpePa-tion, ORNL-4658 (December 1971) 9 p * 3 3 .

L. B.

L-4782, p a 8 4 .

71. B. W. EIorgan, personal csrrrmunication. 72.

Anal. Ckem. Diu. Ann. P r o p . Rept., p e

78.

..... . .! ~

i......

OR%aE4938 (September 30, 19731,

29.

Kiralbis, Copere, Jenks and Rainey, '%'Fluorine Evolution form S o l i d F l u o r i d e s Under I r r a d i a t i o n " , Reactor C h m . Div. AYE?. EYog. Rept. J m u q 32, 1964, B%a?L-3591, p . 29.

6-106 79

80 *

D. E. I r i s h in Ionic Ln$eeractions, Academic Press, 1971, p. 187.

V Q ~ .2 ,

S. Pet~ucci,Ed.,

B. G i l b e r t , p r i v a t e communication. 0

J. B. Bates and 6 . E . Boyd, " I n f r a r e d Emission Spectra of Molten S a l t s , q rAppZ. Speetr. 27: 204 ( 1 9 7 3 ) .

L. D. Kreuzer, N . D. Kenysn and C. K. N . P a t e l , " A i r P o l l u t b o n : S e n s i t i v e Detection of Ten P o l l u t a n t Gases by Carbon Mo~~oxFde and Carbon Dioxide ~ a s e t - 9", Scceme 177: 347 (1972)

p. L. Whiting, G. ~ a m m t o vand J. P . Young, "E%ectrochemical Generation and Spectrophotometric Study o f S o l u t e Species in PaoEten Flusride Media," J . Insrg. l q i v , ~ Z . Chm. 35 : 1553 (1973) e

... ...

... ....

A s i g n i f i c a n t e f f o r t i n t h e development of MSB's w i l l b e devoted t o a comprehensive s t u d y of t h e s a f e t y of all a s p e c t s of such systems. I n g e n e r a l , t h e work in t h i s area proceeds from t h e assunpcion t h a t i f such r e a c t o r s are c o n s t r u c t e d , they w i l l b e designed, b u i l t , and o p e r a t e d normally so as t o avoid any s i g n i f i c a n t r i s k s t o t h e p u b l i c kealVr~ and s a f e t y . In a d d i t i o n , it i s assumed t h a t t h e p l a n t s will b e a b l e to deal safeEy w i t h a v a r i e t y of u p s e t c o n d i t i o n s which might reasonably be expected t o occur several t i m e s d u r i n g the l i f e of any g i v e n system. However i t i s a l s o assumed t h a t l o w - p r o b a b i l i t y e v e n t s , or combinations of events, may o c c u r w i t h consequences t h a t are more severe t h a n t h o s e a s s o c i a t e d with t h e more probable o c c u r r e n c e s These p o s t u l a t e d e v e n t s and t h e i r consequences w i l l b e analyzed as completely as p o s s i b l e to h e l p d e f i n e t h e margins of s a f e t y t h a t are a p p l i c a b l e t o normal operat i o n as well as t o more c l e a r l y e s t a b l i s h t h e s a f e t y c h a r a c t e r i s t i c s of m o l t e n - s a l t s y s t e m in h i g h l y abnormal circumstances. e

.;B

7 lo l e

....

&!i

Objectives

The primary a b j e c t i v e of t h e work i n r e a c t o r s a f e t y i s t o provide a n a l y s e s of p o s t u l a t e d a c c i d e n t s i n p r o g ~ ~ ~ . ~ s i vger % e ayt e r d e t a i l as t h e technology sf m o l t e n - s a l t r e a c t o r s evolves t o e n s u r e t h a t t h e req u i r e d degree of s a f e t y i s achieved. It i s a n t i c i p a t e d t h a t t h e s e a c c i d e n t s t u d i e s w i l l c o n t r i b u t e t o t h e d e f i n i t i o n of component, subsystem, and system s a f e t y requirements and, t o some e x t e n t , t o t h e e s t a b l i s h m e n t of d e s i g n and performance c r i t e r i a t h a t w i l l make t h e s y s t e m compatible w i t h the o v e ~ ~ i a b s al f e t y o b j e c t i v e s sf t h e program. t h e t e ~ h n 0 1 0 g yt h a t is developed w i t h i n o t h e r 81-888 Sf t h i s Program is s a f e t y - r e l a t e d and w i l l , t h e r e f o r e , b e a p p l i e d t o t h e s a f e t y a n a l y s e s t h a t are performed. However, some a s p e c t s of the o v e r a l l technology are uniquely i d e n t i f i a b l e with t h e q u e s t i o n of r e a c t o r s a f e t y , e.g., material system p r o p e r t i e s and c h a r a c t e r i s t i c s under c o n d i t i o n s that are encountered o n l y d u r i n g a c c i d e n t s . Thus, i n s i t u a t i o n s where t h e r e q u i r e d s a f e t y technology cannot b e developed by r e a s o n a b l e extens i o n s of e s t a b l i s h e d e f f o r t s w i t h i n base-technology areas i t w i l l b e developed w i t h i n t h e area of r e a c t o r s a f e t y . The o b j e c t i v e s of such s a f e t y technology development e f f o r t s are t o p r o v i d e a l l of t h e i n f s r m t i o n shown t o b e r e q u i ~ e e ff o r t h e comprehensive d e s c r i p t i o n of t h e s a f e t y of m o l t e n - s a l t r e a c t o r systems. K U C ' ~ of

.... a

S t u d i e s w i t h i n t h e area of r e a c t o r s a f e t y are concerned p r i n c i p a l l y w i t h t h e c h a r a c t e r i s t i c s and b e h a v i o r of m t e ~ i a l s ,c o ~ l l p ~ n e n t ss,u b s y s t e m , and systems i n abnsmal circumstances t h a t would b e expected t o occur very

7-1 ..... .:.:E<,

i n f r e q u e n t l y , i f a t all, d u r i n g t h e a n t i c i p a t e d l i f e t h e of any given p l a n t However, t o t h e extent t h a t t h e more noma1 o p e r a t i o n s of t h e p l a n t define system c o n d i t i o n s that may be a f f e c t e d by a c c i d e n t s , some c o n s i d e r a t i o n must a l s o be g i v e n t o t h e n c s m l behavior. E x i s t i n g s a f e t y and s a f e t y r e l a t e d technology, developed e i t h e r within t h e MSR program o r w i t h i n o t h e r f o r e i g n 8% d m e s t i e r e a c t o r s a f e t y programs w i l l be rsssessed, adapted as r e q u i r e d , and adopted f o r a p p l i c a t i o n t o t h e s a f e t y e f f o r t whenever such a d o p t i o n s are c o n s i s t e n t with t h e Q W K ~ % ] ~program objeetives. A d d i t i o n a l s a f e t y technology w i l l b e developed w i t h i n t h i s area o n l y when unique, specific needs are i

Since the safety sf MSR's has n o t been ad r e s s e d completely t o date, the i n i t i a l efforts will e x m i n e all p o s t u l a t e d a c c i d e n t s to permit clear identification of the IsW-prsbabiIity b u t potentially high-conseq~ence events t h a t wil% e s t a b l i s h t h e s a f e t y c h a r a c t e r i s t i c s of these systems and h e l p to d e f i n e t h e weeds f o r a d d i t i o n a l s a f e t y and s a f e t y - r e l a t e d technology. D e t a i l e d s t u d i e s ~ 5 1 % b e c a r r i e d out p r i m a r i l y for t h o s e event sequences whose combined p r o b a b i l i t y of occurrence and p o t e n t i a l consequences q u a l i f y them as high r i s k e v e n t s , Some studies w i l l a l s o b e d i r e c t e d t o t h e events wi%h p o t e n t i a l l y very severe consequences t o deternine t h e Himits of s a f e t y . Events whose p o t e n t i a l consequences do not reach safety significance w t l l not be e v a l u a t e d i r e d e t a i l . These s t u d i e s will r e l y extensively on a n a l y t i c a l t e c h n i q u e s , mathematical models, computer programs, and d a t a t h a t are developed i n o t h e r task groups in this area as w e l % as in o t h e r technology areas, h%swev@r, s p e c i a l cons o l i d a t e d models and computer programs may be developed w i t h i n t h i s task group i f t h e y are uniquely a p p l i c a b l e t o comprehensive MSW s a f e t y s t u d i e s .

h~rs important: product 0% the guidance s t u d i e s is the i d e n t i f i e a t i o n of technology and d a t a needs for suecessfuli achievement of t h e area objectives. It i s a n t i c i p a t e d that such s a f e t y and s a f e t y - r e l a t e d needs as are f d e n t i f i e d a d j u s t i f i e d in t h i s t a s k group w i l l be f u l f i l l e d by a c t i v i t i e s i n o t h e r t a s k groups o r techsnolsgy areas. 9.1.2.2

Task Group 6 . 2

Fission product behavior

The effort under this task group will. develop d a t a and models t o d e s c r i b e t h e behavior of f i s s i o n products and t r i t i m U T X ~ K c o n d i t i o n s t h a t are not encountered d u r i n g e i t h e r noma1 o p e r a t i o n o r reasonably a n t i s i p a t a b l e t r a n s i e n t s i t u a t i o n s . To t h e e x t e n t that o t h e r primary-system materials

&.,.

7-3

participate in the determination of fission-produet behavior (e.g. formation of special chemical compounds O K physical phases that contain fission products), this work will be coordinated with e f f o r t s in Task Group 6 - 3 . Data and mde%s developed in s t h e r technology areas will b e a d o p t e d whenever possible. However, specialized tests may be performed to v e r i f y t h e applicability of base-technology data ts accident conditions or to ~~ITIQXIstrate the validity of extrapolation from base to accident esnditions. 7.1.2.3

Task Group 6 . 3

Primary system materials

S.P.2.4

Data and models will be developed to d e f i n e t h e respenses and failure mdes of MSR components and systems under severe accident c o n d i t i o n s t h a t are peculiar ts this reactcar type. In areas of e o m o n a l i t y , component and system s a f e t y t ~ d ~ n o h tghja t is developed in other reactor programs will be adopted and applied to PER system counterparts. Bowever, the unique nature of many MSR components and systems, as well as differences in conditions t h a t pllity result frown accidents, are expected to require some separate safety technology development. 7.1.2.5

Task Group 6.5

Safety instrumentation and c o n t r o l s technology

This task group is concerned with the identlfication of needs f o r and t h e d e v d ~ p ~ ~ ~ofe nspecialized t instruments and system that are uniquely appEisable to p c ~ s t u l a t e dsafety-significant situations in PSR system. TechnPques and systems that are available or are developed to meet the needs f o r normal operation and protection of the plant will be examined to determine the degree to which they satisfy s p e c i a l safety needs. Equipment and SySteUXS deVelbOpTllf2nt W i l l be UXldertakeIl O b t a y i n tk0Se BKeaS W h e K e s a f e t y needs would not be met by other development activities.

7.1.2.6

7-4

7J.2.7

Task Group 6.7

S a f e t y technology of p r o c e s s i n g and by-product

S i n c e t h e i n v e n t o r y of radioactfve materials i n an MSBI system i s aist r i b n t e d throughout t h e complexg i n c l u d i n g the p r o ~ e s s f n gp l a n t and shorta d htC?mediate-telXl by-product s t o r a g e facilities, f u l l e o n s f d e r a t i o n w i l l b e given t o the s a f e t y a s p e c t s of p r o c e s s i n g , s t o r i n g , and h a n d l i n g MSR fuel and by-product materials. These s t u d i e s will i d e n t i f y needs for and develop t e ~ h ~ ~ o l oand g q ~neth hods required to protect a g a i n s t and m i t i g a t e t h e eonsequences of abnormal e v e n t sequences that could involve s i g n i f i c a n t r i s k s . The work dll address p r i m a r i l y any special a s p e c t s t h a t may arise from t h e f a c t s that MSR materials and by-products may b e d e a l t with in d i f f e r e n t p h y s i c a l and chemical $oms f r o m t h o s e handled at o t h e r nuclear f a c i l i t i e s and t h a t d i f f e r e n t m i x e s of p o t e n t i a l l y hazardous mater i a l s are involved (e.g., actingdes and f i s s i o n p r o d u c t s are handled and stored SepaKately o u t s i d e t h e r e a c t o r but both may be i n a s s o c i a t i o n w i t h chemically t o x i c m a t e r i a l s ) .

7.1.3

Relation t o o t h e r technology areas

A l l other teehoPog)r areas &thin the MSR p?,?t3gra are 8tk8ngly interrelated with the r e a ~ t ~ s arf e t y area. H Q W ~ V ~ P as, i n d i c a t e d above i n the d i s c u s s i o n of t h e scope of t h e s a f e t y a c t i v i t i e s , t h i s area draws h e a v i l y upom t h e s a f e t y - r e l a t e d technolo t h a t i s developed w i t h i n other areas as w e l l as upon r e l e v a n t s a f e t y s a f e t y - r e i a t e a technology tihat is developed w i t h i n other r e a c t o r p rams. Where p r a c t i c a l , i n p u t and some support w i l l b e provided from t h e s a f e t y s t u d i e s to ensure t h a t technology i s developed w i t h s u f f i c i e n t c a p a b i l i t y , ranges and accuracy t o be d i r e c t l y applbieable to s a f e t y work. P n d e p e ~ d ~development ~t of s a f e t y technology & r i l l b e undertaken only If the ~ e q ~ i r ei ndf o m a t i o n is not expected t o bec m e a v a i l a b l e f r o m o t h e r S O U K C ~ S . However, independent assessments of technology developments from oth@r areas w i l l b e p e r f o m e d t o e v a l u a t e t h e i r a p p l i c a b i l i t y t o safety considerations. 7.2 7.2.1

BUDGET .AJ!JD SCHEDULE Schedule

Work in the area of r e a c t t ~s a f e t y is expected t o eontimue th-oughout He Program. A s shorn in Table 7.2.1, t h e i n i t i a l a c t i v i t i e s are a s s o c i a t e d w i t h the a n a l y s i s of p o s t u l a t e d accidents i n v a r i o u s con-ceptual designs and the i d e n t i f i c a t i o n of needs fo: s a f e t y technology. Subsequently, work i s initiated t o develop technology that is not l i k e l y t o become a v a i l a b l e through o t h e r r e a c t o r development activities. This work could extend beyond t h e t h e p e r i o d s shown i f additional needs a r e idEintified and j u s t i f f e d . B O W e V e K , ft 19 =pe@t'%d that I I l O S t Of the a b l be developed in o t h e r a c t i v i t y areas i n the program r efforts will be r e q u i r e d to assess and a d a p t it for the safety program.

Table 7.2.1.

Schedule

fb)r work on reactor

safety

1986

Fission

product

behavior

Pr~ry

systems material.

Component and systems technology conditims)

(acxident

6.5

Safety instrumentation and controls techncsl.ogy

6.6

MaPmtenanee technology (post accident)

6.7

Safety technoao~ of prscessing and waste storage and handling

7-6 9*2.2

The financial s u p p o r t r e q u i r e d f o r the c u r r e n t l y p r o j e c t e d safety work i s shown i n Table 9 . 2 . 2 . The initial fun f o r accident analyses antieipates studies of several concepts. Late rn 1979, there is a decrease in this work as conceptus% d e s i g n s are b e i n g f i m e up, and a subsequent h l c r e a s e for th@ V e K y d e t a i l e d analyses h SUppOrt of t h e design and CORs t r u e t i o n of p a r t i c u l a r systems. Only a small m o u n t of s u p p o ~ ti s shown f o r d e v e l o p i n safety technology. A d d i t i o n a l support may be weeded for S U C ~work in the period beyond E;"s 1982 if technology needs not OW ident i f i e d must be s a t i s f i e d . The p r o j e c t e d funding i s based on t h e assumpt i o n t h a t , as the construction of r e a c t o r s is undertaken, there w i l l be a d e c r e a s i n g need f o r work i n t h i s area.

The r e a c t o r s a f e t y e f f o r t is e k o s e l y t i e d eo t h e work a s s o c i a t e d w i t h t h e development, desfgn, and c o n s t r u c t i o n of r e a c t o r s . Hence, the i n i t i a l round of s a f e t y analyses should be completed i n FP 1978 t o p r o v i d e a b a s i s f o r t h e r e q u e s t f o r a u t h o r i z a t i o n of t h e MSTR and the MSTB mockup. The development sf needed s a f e t y technology shou%d be l a r eky completed by E T 1983, SO t h a t i t can be used in analyses t o support P i s e n s i n g sf the m"%* Most of the safety a n a l y s i s of the MSTR should be completed by 1985, when c o n s t r u c t i o n sf- t h a t f a c i l i t y i s p r o j e c t e d t o b e g i n .

7.3.1

The s a f e t y requirements, o r s a f e t y performance c r i t e r i a , t h a t a r e a p p l i c a b l e t o MSR systems are prestamed to be equivakesrg. t o t h e i n t e n t of s i m i l l a r requirements f o r n u c l e a r f a c i l i t i e s embodyin o t h e r r e a c t o r c o n c e p t s . Thus, he s t a n d p o i n t of safety, i t i s assumed t h a t t h e numerical guidance ed in 3.0 CFR 160 f o r doses f r o m fission product releases a p p l i e s %S W complex, whafsh i n c l u d e s t h e chemical p ~ ~ g s s i nsystem g and the o n - s i t e w a s t e s t o r a g e g a c i ~ i t i e s . ~( ~ the n MSBR, a l l f u e l r e p r o c e s s i n g i s c a r r i e d o u t a t t h e ~ e a c t s bs i t e , t h e r e b y e l i m i n a t i n g r o u t i n e releases of r a d i o a c t i v i t y from o t h e r reprocessin facilities. while i t i s c o n c e i v a b l e t h a t some c s g n i z a n s e may have t o be taken of t h i s f a c t i n e v a h a t i n g rout i n e releases from normal o p e r a t i o n , it. i s not clear t h a t s i m i l a r considerations should be a p p l i e d t o s a f e t y a n a l y s e s . 1 Because ~f t h e f ~ n ~ a ~ dei fnf e~r e n a c~e s between m o l t e n - s a l t reactors and other ~ e a c tty p~e s~, i t i s r e a s o n a b l y c l e a r t h a t d i f f e r e n t safety proviineered s a f e t y f e a t u r e s w i l l be r e q u i r e d to h e l p prevent a t e t h e consequences of major a c c i d e n t s . For exmp%.e,i t cur p e a r s that emergency core coolin c a p a b i l i t y may not be KeqUired b u t t h a t 8 h i h l y r e l i a b l e , and p o s s i b y redundant, d r a i n $a& C O O l b g System may be needed iXlSteikd. k.Y2Urate deSCKipti0n.S 0% the s a f e t y r e q u i r e m e n t s of E E R P s will be developed from t h e d e t a i l e d s a f e t y s t u d i e s t o be performed.

Tablie 7.2.2.

6.1

Guidance

studies

6.2

Fission

product

6.3

Prhry

6.4

CoqQntent ana. syste!ms technals~ (accident csHlditiam)

6.5

Safety instrarmentatian and cmtroPi3 techndegy

6.6

Heifwtenance technolsgg (pcmt aeeident)

6.7

Safety teehnslaagy Qf processhqg and wa5te storage and hanaling

Summry of operating (cssts

fund requirements in 1000 dollars)

for

WQPTS. on reactor

360

390

behavior

systelns material

_____-__-___

safety

485

600

650

7-8 7.3.2

Background

In discussing the safety considerations of importance in MSR's it will b e convenient to treat three general areas -neutronic safety, which includes primarily those characteristics of t h e plant t h a t determine the p o s s i b l e changes in the reactivity of t h e core a d the resulting response of the nuclear power and the temperatures and pressures in t h e primary system; materials safety, in which the behavior and interactions of varPous materials in the system a f f e c t the safety consequences of h p o r t a n t events; and system safety, which includes the safety behavior sf ma;jo~subsystem, suck as containment, as w e l l as t h e system as a whole.

_.,

reference design MSBR statim, including t h e processing plant and the interim waste storage facilities. The purposes however, is to delheate t h e important factors that must be considered for any molten-salt reactor. The emphasis 1s on events with potential safety significance but same discussion of less severe events is included to p r o v i d e perspective. This section deals primarily with the ON%

5.3.2.1

Neutronic safety considerations

The general principles of neutronic safety are the same f o r all reactors. Small fluctuations in reactivity should produce only highly damped power oscillations that do not lead to larger excursions. Large, rapid increases in reactivity should be difficult to produce and be e a s i l y csntrolled b e f o r e the resulting power excursions produce dmagimg temperature or p r e s s u r e excursions. The characteristics of the XSBR p l a n t are such that these

pr-inciples cam be satisfactorily met. T3ie csntinusua removal of fission pro ucts and the adjustment of the fissile inventory in the fuel salt during operation of the MSBR minimize the amount O ~ and hence of excess reactivity t h a t must be compensated by C Q I I ~ ~ rods limit the potential for rapid increases in reactivity associated with this excess. In the reference-desie %BR, the maximum mount of excess reactivity t h a t nust be compensated by rods mder noma1 conditions is expected to be less than 1% Sk/k. Thus, the c~nsequencessf even the most severe control-rod accidents are n o t likely to reach safety significance

The f i s s i l e IMterhl in t h e On-line processing system a Q U X I t % t h a less thaw 1% of t h e reactor inventory. If all of this material c o u l d be returned to the ~ e a c t ~ rthe , excess reactivity would be increased only 8.4% or less. Furthemore, conceivable rates of reactivity int~oductionare quite inconsequential,* so accidents invoPving this material are well below the range of safety concern.

*The rate of reactivity i n ~ r e a @would ;e be only 5 x IO-% 6k/k per second if the 3 Biterlwin s a l t stream f ~ o mthe processing plant to the 48,000liter reactor fuel system contained tss2.e the noma1 uranium concentration.

h.,

7-9

... .... , .a

.... ,.:.:.x

....

_ I

-.;.;.&

Decay of p r e c u r s o r s i n the f u e l c i r c u l a t i n g o u t s i d e s f t h e c o r e reduces t h e e f f e c t i v e delayed-neutron f r a c t i o n from 0.38% t o 0.12% i n an o p e r a t i n g MSBR. Thus one r e s u l t of a c e s s a t i o n of f l o w i s a 8.18% bk/k r e a c t i v i t y i n c r e a s e i n a t i m e on t h e o r d e r of t h e h a l f - l i v e s of delayed-neutron prec u r s o r s . Somewhat l a r g e r r e a c t i v i t y e f f e c t s of s t o p p i n g and s t a r t i n g f u e l c i r c u l a t i o n could r e s u l t from t h e p e r t u r b a t i o n s of temperatures and t h e e f f e c t s of changing p r e s s u r e on g a s bubbles i n t h e c o r e . The m a h u m e f f e c t of temperature changes i s shown by t h e f o l l o w i n g argument t o be q u i t e manageable. The r e a c t i v i t y c o e f f i c i e n t fer changes i n t e m p e r a t u r e of t h e e n t i r e core (-Os 9 x "C-p> is much smaller t h a n t h e c o e f f i c i e n t f o r the f u e l alone ( - 3 . 3 x '6-l f o r a uniform change of fuel temperature over t h e e n t i r e core). Thus t h e upper bound on r e a c t i v i t y e f f e c t s due t o a t e m p e r a t u r e change i n t h e c o r e corresponds t o c o o l i n g a l l t h e core f u e l (and none of t h e g r a p h i t e ) from the maximum o p e r a t i n g temperThis i s o n l y about a t u r e (705°C) t o t h e f u e l l i q u i d u s temperature (500'C). 0.7% &/le. E f f e c t s a c t u a l l y a t t a i n a b l e are smaller and, because they can ~ ~a t s be produced only by i n f l o w of c o o l e r s a l t , occur w i t h t i m e c ~ n ~ t a of least several seconds. The s a f e t y r o d system i s q u i t e c a p a b l e of greventing power e x c u r s i o n s due t o such e f f e c t s . Because of t h e s t r o n g a b s o r p t i o n s i n t h o r i m i n t h e f u e l s a l t , displacement of a m a l l f r a c t i o n of the s a l t by v o i d s h a s a p o s i t i v e e f f e c t on r e a c t i v i t y . There a r e , i n p r i n c i p l e , two ways t h i s could occur: (I) by i n c r e a s e s i n t h e volume f r a c t i o n of c i r c u l a t i n g , noneondensable g a s , and (2) by b o i l i n g of the f u e l salt (vapor p r e s s u r e equals 1 a t m at ~ 1 4 0 0 ' C ) . N e i t h e r of t h e s e p r o c e s s e s appears to be c a p a b l e of producing changes of s u f f i c i e n t magnitude t o r e p r e s e n t a s a f e t y problem. Under n o m a 1 o p e r a t i n g c o n d i t i o n s t h e f u e l s a l t i n an MSBW c o n t a i n s 0.2 t o 1.6 vol % of helium bubbles. This gas i s i n t r o d u c e d and removed conn the r a t e sf a d d i t i o n o r ret i n u o u s l y t o s t r i p 1 3 5 ~ e nT ~ U S , changes i moval o r changes i n system p r e s s u r e w i l l , change t h e core v o i d f r a c t i o n . A t 1 vol 2 , t h e v o i d s i n t h e r e a c t o r core r e p r e s e n t about 0.039% i n rea c t i v i t y . A complete d e p r e s s u r i z a t i o n of t h e f u e l system, which would allow t h e s e bubbles t o expand by a f a c t o r of 2 t o 3 , would cause a react i v i t y i n c r e a s e of o n l y about 0.1% 6k/k. I n a d d i t i o n ts t h e bubbles, t h e s a l t c o n t a i n s some d i s s o l v e d helium and t h e pores of t h e g r a p h f t e c o n t a i n s u b s t a n t i a l l y more. Although t h e t o t a l mount of helium 2n t h e g r a p h i t e is l a r g e , t h e r a t e a t which i t can d i f f u s e o u t i s l i m i t e d so t h a t f o r r e a s o n a b l y a t t a i n a b l e rates of p r e s s u r e l o s s in an MSBR (-2 psigsec) the combined r e a c t i v i t y e f f e c t due t o bubble expansion and g r a p h i t e outg a s s i n g i s only 0.085 ( X Gk/k)/sec OK less. Voiding of a few channels by l o c a l b o i l i n g (as might result if f l o w blockages o c c u r r e d i n i n d i v i d u a l f u e l p a s s a g e s ) i s n o t a severe e v e n t . The p o s i t i v e r e a c t i v i t y e f f e c t a s s o c i a t e d w i t h 100 empty f u e l cells a t the

...., .m

*A f u e l c e l l , as used h e r e , means t h e 4 i n . by 4 i n . by 16 ft long region a s s o c i a t e d w i t h a s i n g l e moderator p i e c e .

..... .::.g

9-10 average nuclear importanace f o r t h e c e n t r a l core r e g i o n i s less t h a n Q e 5 X Gk/k. Because t h e b o i l i n g t e m p e r a t u r e (at l atnn) i s more t h a n 7OQoC above t h e n o m a o p e r a t i n g temperature of the s a l t , the energy i n p u t r e q u i r e d t o heat the s a l t t o t h e b o i l i n g t e m p e r a t u r e over a s i g n i f i c a n t p o r t i o n of t h e care i n a s h o r t t i m e would r e q u i r e a n u c l e a r e x c u r s i o n l a r g e r t h a n any produced by c r e d i b l e r e a c t i v i t y i n p u t s . Thus, boiling in t h e c o r e w i l l n o t come i n t o p l a y as a p o s i t i v e r e a c t i v i t y feedback i n any nuclear e x c u r s i o n o r i g i n a t i n g with t h e r e a c t o r a t o r near normal temperature. Displacement of s m a l l m o u n t s of f u e l salt by g r a p h f t e p ~ ~ d u c ea sp o s i t i v e r e a c t i v i t y e f f e c t . A t t h e c e n t e r of t h e c o r e ( t h e most s e n s i t i v e s p o t ) Goneeivable e v e n t s , i n t h e e f f e c t amounts t o 2.9 x lo-fjz 6k/k p e r cma c l u d i n g sudden r e d i s t r i b u t i o n of c l e a r a n c e s i n response t o f l o w changes or accumulated stresses, produce no r e a c t i v i t y i n c r e a s e of muck c~nsequence. e

A unique c ~ n s i d e k a t i o nin f l u i d - f u e l reactors is t h e p o s s i b i l i t y of i n homogeneity of t h e f i s s i l e t e r i a l in t h e c i r c u l a t i n g f u e l . S p e c i f i c a l l y of concern i s g r a d u a l s e g r e g a t i o n of f i s s i l e material outside the core, fo%Eowed by r a p i d introduction w i t h t h e inesming stream. The MSBR f u e l s a l t i s q u i t e s t a b l e Q V ~ Ka range of compositions and c o n d i t i o n s much wider t h a n the anticipated d e v i a t i o n s . S e g r e g a t i o n of uranium could conceivably b e produced by i n t r o d u c t i o n of reducing a g e n t s o r oxygen i n t o t h e salt, s o a d e q u a t e p r o t e c t i o n a g a i n s t this must b e provided i n t h e mBR.

.... c.x.:

The response sf the n u c l e a r power t o r e a c t i v i t y i n c r e a s e s i s g ~ e ~ n ebyd t h e temperature c o e f f i c i e n t s of r e a c t i v i t y and t h e a c t i o n of t h e c o n t r o l rods and s a f e t y r o d s . Because t h e delayed n e u t r o n f r a c t i o n i s unusually small, the WBW power responds r a p i d l y t o r e a c t i v i t y i n c r e a s e s . The r e a c t i v i t y c o e f f i c i e n t s f o r urnifom changes i n f u e l and g r a p h i t e temp e r a t u r e s are l i s t e d i n T a b l e 7 . 3 . 2 . 1 . I n response to r e a c t i v i t y t r a n s i e n t s , c o r e temperature changes w i l l n o t be u n f f o m , however. I n p a r t i c u l a r , t h e g r a p h i t e will change temperature much more slowly t h a n w i l l the f u e l salt. ( I n the c e n t r a l , core region, graphite comprises about 982 of the heat c a p a c i t y but only about 8% of t h e n u c l e a r h e a t s o u r c e i s i n t h e g r a p h i t e . ) Consequently, h e a t i n g of t h e fuel s a l t r e s u l t s in a prompt, n e g a t i v e response of r e a c t i v i t y t o a power excursion. T h i s response i s g r e a t enough to limit e f f e c t i v e l y t h e i n i t i a l power surge caused by any credibly r a p i d i n c r e a s e i n r e a c t i v i t y . Thus s a f e t y r s d s are n o t required t o o p e r a t e unusually f a s t . The t o t a l c o r e t e m p e r a t u r e c o e f f i c i e n t ( f u e l p l u s gxaphite) i s q u i t e s m a l l , however, and might conceivably be p o s i t i v e . (The calculbatecl v a l u e i s n e g a t i v e , but t h e c u r r e n t margin of u n c e r t a i n t y iS Such t h a t t h e e O @ f f i C i e n t C Q U l d tuPn Out t o be p O S % t i V e . ) h a r e s u l t , s a f e t y - r o d a c t i o n is r e q u i r e d to p ~ e ~ e snatf e t y - s i g n i f i c a n t v a r i a t i o n s i n t e m p e r a t u r e t h a t m i h t o t h e r w i s e r e s u l t from any r e a c t i v i t y change t h a t p e r s i s t s more than a f e w seconds.

I n s m a r y , t h e n u c l e a ~s a f e t y c h a r a c t e r i s t i c s of t h e r e f e r e n c e MSBR are such t h a t a r e a c t i v i t y e x c u r s i o n l e a d i n g to a breach i n t h e primary system boundary appears t o be highly u n l i k e l y .

.... e,<.:.

....

i.5-L'

7-11

Table 7.3.2.1.

C o e f f i c i e n t s o f r e a c t i v i t y f o r uniform changes i n t e ~ ~ p e r a t u racross e the MSBR core Reactivity coefficient,

Component

Fuel. s a l t Doppler e f f e c t " Themal bas e** D63lSitY

+o .82

Total f u e l salt

-3 28

Graphite Thermal base** Density

+2.47 -0.12

T o t a l graphite

+2 .%5

Core ..... _...... ._a

...:,a

.... .... :<.>a ..L

-4 * 3% # .27

-0.87

*P r i m a r i l y due to thorium.

**Upward s h i f t s in t h e m 1 spectrum hcrease r e a c t i v i t y because f i s s i l e cross sections decrease less r a p i d l y t h a n t h e thorium cross s e c t i o n does a

7-12

Although n e u t r o n i c a l l y d r i v e n events appear to o f f e r l i t t l e l i k e l i h o o d of causing serBous damage to t h e primary system of an MSR, o t h e r e v e n t s and p r o c e s s e s must b e considered which might e i t h e r c a u s e such damage o r i n crease t h e v u l n e r a b i l i t y of t h e primary system t o damage. Among t h e s e are cor-k-~sionp r o c e s s e s and p o s s i b l e i n t e r a c t i o n s among the v a r i o u s materials S € t h e primary, secondary, and steam systems.

....

K.L

H a s t e l l ~ yN i s corroded by MSBR f u e l s a l t under n o r m 1 c o n d i t i o n s by r e a c t i o n s of the t y p e

where !dB r e p r e s e n t s any m e t a l t h a t i s therrnodynawically capable of reduehe r a t i o U F ~ / U Fi ~ n t h e f u e l s a l t i s maintained at a ing the ~ 4 +i o n . v a l u e such that e q u i l i b r i u m i s reached w i t h c o n c e n t r a t i o n s of Ni2', Fe2+% and M O ~ + i n the s a l t t h a t a r e much less than 1 ppm and a chromium coneent r a t i o n less t h a n one hundred ppm. The predominant c o r r o s i o n r e a c t i o n t h e n i s r e a c t i o n of UFq w i t h c h r o m i m i n t h e metal t o farm CrF2 which d i s s o l v e s in the s a l t . Chromium becomes d e p l e t e d wear t h e s u r f a c e and, a f t e r t h e first few thousand h o u r s , c o r r o s i o n i s l i m i t e d by t h e rate o f d i f f u s i o n of chromium t o t h e s u r f a c e . A t MSBR temperatures this l i m i t i s on the o r d e r of 0.1 m i l / y e a r of chromium d e p l e t i o n .

Introduction of m o i s t ~ r eand a i r into t h e f u e l system produces HP and m e t a l oxides, which d i s s o l v e i n t h e salt and make i t more o x i d i z i n g and more c o r r o s i v e t o all c o n s t i t u e n t s of H a s t e l l o y Ea. During normal ~ p e r a t i o n t h e contaminants can b e k e p t low by c o n t r o l l i n g t h e composition sf t h e cover gas. Maintenance o p e r a t i o n s w i l l almost i m e v i t a b l y i n t r o d u c e some ~ a ~ i s t u r eb u , t with r e a s o n a b l e p r e c a u t i o n s to minimize air i n l e a k a g e , c o r r o s i o n from t h i s cause w i l l have n e g l i g i b l e e f f e c t on primary system (Corrosion i n t h e MSRE f u e l system, which w a s opened t w o o r integrity. three t i m e s a year, averaged only 0.1mil/year. 1 3 ~ h u ,s i t does n o t appear t h a t normal C W T C I S ~ Q ~ p r o c e s s e s w i l l b e i n v o l v e d i n s a f e t y c o n s i d e r a t i o n s . A somewhat r e l a t e d process that m i g h t conceivably a f f e c t t h e s a f e t y of t h e s t P u c t U P a i alloy by s p e c i f i c fission prodM S R V is ~ direct: a t t a c k u c t s - such as the i n t e r g r a n u l a r a t t a c k by t e l l u r i u m on HastelPoy N t h a t W a s observed i n the MSm. mil@t h i s p a P t i c d a K problem W i l l presurn;bbly b e s o l v e d by efforts i n o t h e r areas, s t u d i e s w i l l b e needed t o show t h a t no similar problems e x i s t i n t h e system that i s f i n a l l y evolved.

k..

Salt-graphite interactions

The g r a p h i t e In t h e core of a m o l t e n - s a l t r e a c t o r i s e s s e n t i a l l y an i n e r t c~mponentunder nsrmal o p e r a t i n g c o n d i t i o n s . It i s not subject t o e i t h e r

7-13

c o r r o s i v e o r e r o s i v e a t t a c k by the c i r c u l a t i n g s a l t . S i n c e t h e s a l t does mot w e t g r a p h i t e s u r f a c e s , t h e r e is no permeation of s a l t into t h e p o r e s and any tendency f o r such permeation would be f u r t h e r reduced if it w e r e n e c e s s a r y t o seal the p o r e s t o reduce xenon poisoning. However, some xenon (and o t h e r g a s e s ) will d i f f u s e i n t o the g r a p h i t e and leave behind t h e p r o d u c t s of r a d i o a c t i v e decay. A d d i t i o n a l f i s s i o n p r o d u c t s will be deposited on t h e g r a p h i t e s u r f a c e s . Except f o r t h e i r c o n t r i b u t i o n to a f t e r h e a t (in t h e g r a p h i t e ) t h e s e f i s s i o n p r o d u c t s are n o t expected t o a f f e c t the g r a p h i t e s t r u c t u r e , even under a c c i d e n t c o n d i t i o n s . I n t e r a c t i o n s between t h e s a l t i t s e l f , o r i t s major c o n s t i t u e n t s , and g r a p h i t e have n o t been thoroughly examined for t h e c o n d i t i o n s t h a t might develop i n 8 s e r i o u s a c c i d e n t . The b o i l i n g of s a l t a t or n e a r g r a p h i t e s u r f a c e s , as might occur under some c o r e blockage c o n d i t i o n s , h a s n o t been s t u d i e d w i t h r e s p e c t t o e f f e c t s of e i t h e r t h e b o i l i n g i t s e l f o r the v a p o r s t h a t would b e produced. E f f e c t s due t o changes in s a l t chemi s t r y as a result of i n t r o d u c t i o n of f o r e i g n materials during a c c i d e n t s a l s o have not been examined i n d e t a i l .

Salt-to-salt

interactions

The

Of NaBF4 - NaF (92-8 mole X ) was chosen as t h e secondary s a l t 5n t h e r e f e r e n c e MSBR because i t has r e a s o n a b l y good c o o l a n t p r o p e r t i e s , it i s r e l a t i v e l y i n e x p e n s i v e , and i t s m e l t i n g p o i n t (725°F) 1s l o w cornIQEiKgif t 0 that sf many o t h e r s u i t a b l e f l u o r i d e m i x t u r e s . Prom t h e s a f e t y s t a n d p o i n t i t i s h p o r t a n t : t h a t m i x i n g of fuel and c o o l a n t s a l t should n o t give arise t o s i t u a t i o n s that could endanger t h e h e a l t h and s a % e t y of t h e p u b l i c o r of the o p e r a t o r s of t h e p l a n t .

me e v e n t t h a t could produce mixing of f u e l and c o o l a n t s a l t s i s a l e a k i n a primary heat exchanger. The l a r g e s t l i k e l y l e a k of t h i s kind i s b d i e v e d to r e s u l t f r o m the X Y I ~ ~ Uof P ~ one t u b e in one of t h e h e a t a-

....

... .... .....

::&

changers. Depending on t h e l o c a t i o n of t h e r u p t u r e , coolant s a l t would e n t e r the f u e l s a l t i n the prinnary system a t an i n i t i a l rate i n t h e range of 8 t o 3.5 Ilb/see and f u e l s a l t would e n t e r t h e c o o l a n t s a l t a t a r a t e i n t h e range of 1.8 t o 7.4 l b 8 s e c . That the l e a k existed would be sign a l e d by r a p i d loss i n r e a c t i v i t y of t h e r e a c t o r o r f i s s i o n product r a d i o a c t i v i t y i n a secondary c i r c u i t o r both. Upon e i t h e r of these s i g n a l s t h e r e a c t o r would be s h u t down r a p i d l y , t h e f u e l s a l t would be d r a i n e d fro~llt h e p r h a ~ ysystem i n t o t h e f u e l s a l t d r a i n t a n k , and t h e c o o l a n t s a l t i n t h e a f f e c t e d secondary c i r c u i t would be d r a i n e d i n t o a c o o l a n t s a l t d r a i n tank. Tple m o u n t of mixing of f u e l and c o o l a n t s a l t s would v a r y widely, depending on t h e d e s i g n of t h e p l a n t and t h e course of t h e w e n t . We e s t h a t e t h a t as much as 450 ft3 of c o o l a n t s a l t could m i x w i t h 1700 ft3 of f u e l salt i n t h e primary system and 40 f t 3 of f u e l s a l t could m i x w ~ t h2100 ft3 sf coolant s a l t i n a secondary c i r c u i t of the referenee MSBR. N o chemical r e a c t i o n s t h a t would g e n e r a t e excessive h e a t OK p ~ e cipidsate c o n s t i t u e n t s of e i t h e r s a l t would be expected t o occur on

....

7-14 mixing, however additional W S K ~ will be r e q u i r e d t o a d e q u a t e l y s u b s t a n t i a t e t h i s ~ ~ p e c t a t i ~ nFuel . s a l t and s o d i m fluorobsrate are hmiseiblte, however, s o two s a l t phases would b e p r e s e n t i n b o t h systems. Although t h e salts are iraznPscible, exchange o c c u r s between t h e phases w i t h lithium and bePyPliurn f l u o r i d e s entering the l i g h t e r flusroborate phase snd s o d f m f l u o r i d e and boron t r i f l u o r i d e moving i n t o t h e f u e l salt phase. Uranium and thorium f l u o r i d e s rash Ln t h e heavy phase. I n t h e primary system the exchange of c o n s t i t u e n t s between s a l t s would n o t be expected t o have a s i g n i f i e a n t e f f e c t on t h e m e l t i n g p o i n t O f t h e fuel salt. The m e l t i n g point of the c o o l a n t s a l t d i s p e r s e d 5n the fuel would i n c r e a s e somewhat, some BF3 would be r e l e a s e d , and t h e BP3 o v e r p r e s s u r e in the primary system would be expected t o rise t o about 5 am. I n t h e secondary system t h e i n t e r a c t i o n between the fuel and coolant salts would tend t o Paise t h e l i q u i d u s t m p e % a t U r e 0% the fUel-CQntaitniRg S a l t b u t would n o t s i g n i f i c a n t l y a f f e c t t h e coolang: s a l t . Since much of the secondary system nomallby o p e r a t e s at a tempe~aturebelow the liquidus of the fuel salt, t h e fuel salt t h a t l e a k e d b t o the secondary system would i n i t i a l l y be d i s p e ~ s e das f r o z e n p a r t i c l e s throughout much of one circuit. %ether t h e p a r t i c l e s remained as s o l i d s would depend on measures taken to heat Q K SO01 the SeCQRdary C % r C U i t a f t e r the C O O % a n t S d % had been d r a h e d Another mechaRism f o r mixing c o o l m t s a l t i n t o the f u e l s a l t (but not vice versa) i s t h e failure of a secondary-salt l i n e w i t h i n the prLmary containment. Since t h e primary containment of t h e r e f e r e n c e d e s i g n funnels a l l s a l t spills t o the fuel d r a i n t a n k , suck an e v e n t could quickly add a major f r a c t i o n of t h e c o o l a n t - s a l t h v e n t o r y of t h e affected h o p t o the fuel salt in t h e drain tank. I f t h e f o u r primary l O S P S C O H l t i R u e d to c i r c u l a t e Salt at f u l l Speed, the draflI-taPlbc Contents would enter t h e primary system a t about 650 gpm (9.170 P b / s e e ) . However, stopping t h e primary-pump motors and c i r c u l a t i n g t h e f u e l s a l t w i t h pony motors would a l l o w removal of shutdown h e a t w i t h o u t h c u r r t n g t h e salt mixing i n t h e primary loop. En any e v e n t , it is likely t h a t the two salts would e v e n t u a l l y become mixed i n the f u e l d r a i n tank. The comeguences of mixing on this scale have not been exmined in d e t a i l , b u t i t i s not expected t h a t they would represent a s i g n i f i c a n t l y reater s a f e t y question than mixing v i a a f a i l e d heat-exchanger tube.

None of the conditions a s s o c i a t e d with mixing s f f u e l and coolant salts 5n t h e pri~11ary o r secondary systems appear t o be capable of producing a break 5n ~ 5 t system. h ~ ~ The secondary c i r c u i t s must be h e a v i l y s h i e l d e d against t h e r a d i o a c t t v i t y p r e s e n t i n t h e c o o l a n t s a l t d u r i n g noma% operat i o n . This s h i e l d i n g can be made a d e q u a t e t o p r o t e c t a g a i n s t the fission p r o d u c t s that would be i n t r o d u c e d by t h e f u e l salt.

Salt-water i n t e r a c t i o n s

Mater and s t e m react with sodium f l u o r o b s r a t e t o produce p r b a r i l y hydrogen f l u o r i d e and s o d i m hydroxyfluoroborate. The ~eactionsare not des t r u c t i v e l y exothemic, b u t the hydrogen f l u o r i d e i s csrrOsive t o the

c,.;.:, I

7-15 metals of t h e r e a c t o r secondary system and the t u b e s t h a t s e p a r a t e the f u e l s a l t f r m t h e c o o l a n t salt. Although t h e corrosion rates are not c a t a s t r o p h i c under any f o r e s e e a b l e circumstance, t h e leakage r a t e of water from the s t e m system i n t o the secondary system and the hydrogen f l u o r i d e c o n c e n t r a t i o n 5n the secondary s a l t must be kept l o w in order t o m a i n t a i n a l o w corrosion rate of p i p i n g and equipment.

In the e v e n t of a - % U P ~ U Pof~ one o r more t u b e s i n a stem g e n e r a t o r or s u p e r h e a t e r , the r a p i d p s e s s u r i z a t f o n of t h e secondary system and the p o s s i b i l i t y of t r a n s m i t t i n g that p r e s s u r e t o the p - a r h a ~ ysystem i s t h e major concern. I s o l a t i o n valves must be provided t o stop t h e flow of feedwater and s t e m t o t h e f a u l t y s t e m g e n e r a t i n g eqraipnent and p r e s sure r e l i e f devices must be provided on t h e secondary system t o keep t h e p r g s s u ~ ebelow t h e system d e s i g n p r e s s u r e . The steam and salt t h a t are d i s c h a r g e d through t h e s e d e v i c e s must be csntatned but %t h a s not been determined i f the r e a c t o r primary c ~ ~ ~ t a i n or ~ ~some ~ e nother t secondary system woraPd be used. S a l t s p i l l s w i t h i n t h e p r h a r y containment will not normally 2nvoEve water ~ c e p for t traces in t h e contain~~~tat atmosphere. H O W ~ V ~ Ss,~ b s e qraent opening of the c o n t a f a e n t f o r maintenance may admit s u f f i c i e n t m o i s t u r e t o allow sme uptake by s a l t r e s i d u e s . I n such eases it may be n e c e s s a r y t o examine the long-term s a f e t y consequences of p o s s i b l e pfping and containment c o r r o s i o n by r e s i d u a l s a l t . Since the primaryc o n t a i ~ ~ I~bnetr may be water-cooled (much like t h e PCRV l i n e r of an HTGR), a s s u r a n c e must b e provided that t h e l h e r c~olfngwater cannot be mixed with s p i l l e d s a l t . Such a double a c c i d e n t , w i t h s u f f i c i e n t water, could Bead t o high containment pressures from s t e m g e n e r a t e d frm t h e s e n s i b l e h@at of the s a l t . 7.3.2.3

System safety c o n s i d e r a t i o n s

The p r e c e d i n g sections i n c l u d e d discussions sf some p a r t i c u l a r aspects 0% safety technology and some specific p o s t u l a t e d accidents. However, t h e r e are a d d i t i o n a l s a f e t y c o n s i d e r a t i o n s t h a t are important throughout t h e p l a n t . h o n g t h e s e are the behavior of fission p r o d u c t s i n MSR systems and the engineered s a f e t y f e a t u r e s of t h e p l a n t .

From the s t a n d p o i n t of r e a c t o r s a f e t y , the chlef importance of radisnnelide decay heat l i e s i n whatever t h r e a t i t m y pose to the i n t e g r i t y of t h e primary system.

.... . :.a

_...

. : . ; . y ,

... ,. :.;< ;, .,a

In M B R , t h e f i s s i o n p r o d u c t s and transmutation p r o d u c t s and the h e a t produced by t h e i r decay are distributed through the r e a c t o r systems and the processing facility in a mnner t h a t depends ow the physical featlsPes of the plant, the chemistry sf t h e r a d i o n u c l i d e s , ~ n dthe extent of rep r o c e s s i n g of t h e fuel s a l t . I n the r e f e r e n c e d e s i g n MSBB, a f t e r several

7 -16 months of o p e r a t i o n a t i t s d e s i g n power o f 2250 Mg(t), t h e t o t a l decay h e a t ra%ei s about 152 MM, d i s t r i b u t e d as shown i n Table 7.3.2.3.1. Most of t h e h e a t i s generated i n t h e f u e l s a l t by t h e decay of a l l classes of r a d i o a c t i v e p r o d u c t s w i t h h a l f l i v e s of a few minutes o r less and of l o n g e r l i v e d p r o d u c t s t h a t a r e s o l u b l e in t h e s a l t . Krypton and xenon d i f f u s e i n t o t h e p o r e s of t h e c o r e g r a p h i t e o r i n t o t h e heEim bubbles t h a t c i r c u l a t e i n t h e f u e l s a l t and a r e removed t o the d r a i n tank. About 80% of t h e energy of decay of t h e gases t h a t r e a c h t h e d r a i n t a n k i s r e l e a s e d i n t h e tank. The remainder i s r e l e a s e d i n t h e carbon beds. FOB. t h e purposes sf c o n s e r v a t i v e d e s i g n , each daughter atom of a noble gas i s assumed t o d e p o s i t on t h e s u r f a c e n e a r e s t t h e p o i n t o f decay of t h e p a r e n t atom and t h e r e to release i t s heat. T h i s c e r t a i n l y i s t h e s i t u a t i o n in t h e g r a p h i t e and i n t h e carbon beds. Depending on the a e s i e , dau ter a t o m born i n t h e off-gas l i n e s o r d r a i n t a n k could e i t h e r b e d i s s o l v e d i n f u e l s a l t and ~ e t u r n e dt o the primary system o r b e c a r r i e d ow with t h e gas stream. The f i s s i o n p r o d u c t s from element 4 1 , niobium, through element 52, t e l l u rium, are n o t s t a b l e as metal i o n s under t h e n o r m 1 redox c o n d i t t o n s i n t h e f u e l s a l t and are r a p i d l y reduced t o t h e e l e m e n t a l state.* These metals are highly i n s o l u b l e i n t h e s a l t and are n o t wet by i t , s o t h e y tend t o d e p o s i t on m e t a l and g r a p h i t e surfaces and coPllect a t g a s - l i q u f d interfaces The d i s t r i b u t i o n of t h e a f t e r h e a t produced by t h e s e materials depends on t h e i r d i s t r i b u t i o n a m n g t h e v a r i o u s s u ~ f a c e s . Table 7 . 3 . 2 . 3 . 1 shows f x o c a l c u l a t e d d i s t r i b u t i o n s f o r t h e af t e r h e a t from metallic f i s s i o n p r o d u c t s , r e f l e c t i n g u n c e r t a i n t i e s i n t h e i r p h y s i c a l d i s t r i b u t i o n . The f i r s t is based on an assumed s t i c k i n g c o e f f i c i e n t - t h a t is, t h e probab i l i t y t h a t a f i s s i o n - p r o d u c t atom remains on t h e s u r f a c e t o which i t migrates - of 1.8 f o r m e t a l and g r a p h i t e s u r f a c e s and 8.1 f o r bubble s u r f a c e s . For the second d i s t r i b u t i o n , t h e stisking c o e f f i c k n t f o r gas bubbles w a s i n c r e a s e d to 1 . 0 and IIQ r e e n t r a i n m e n t w a s allowed i n t h e s a l t i n t h e d r a i n t a n k . The d a u g h t e r s of n o b l e metals are a l s o n o b l e metals which tend t o remain where t h e parent was d e p o s i t e d except f o r i o d i n e , t h e daughter s f t e l l u r i u m . I n t h e presense of f l o w i n g s a l t , i o d i n e ret u r n s t~ t h e l i q u i d phase; o t h e r w i s e i t remains on o r n e a r the s u r f a c e a t which i t w a s formed. The fuel p r o c e s s i n g system i s t h e f i n a l l o c a t i o n i n which a s u b s t a n t i a l amount of r a d i o a c t i v e decay h e a t i s r e l e a s e d . The s o u r c e of heat there. i s roughly e q u a l l y d i v i d e d between 233Pa and f i s s i o n p r o d u c t s of i n t e r mediate t o long l i f e . Decay h e a t g e n e r a t i o n i s a most important f a s t o p i n t h e d e s i g n of this system. The o p e r a t i o n of t h e p r o c e s s i n g system s c a r c e l y a f f e c t s t h e decay h e a t i n g i n t h e r e a c t o r d u r i n g o p e r a t i o n , but does reduce t h e h e a t i n g r a t e s a t l o n g e r times a f t e r shutdown (and decay of t h e s h o r t e r - l i v e d f i s s i o n p r o d u c t s ) . From t h e f o r e g o i n g , i t is e v i d e n t t h a t t h r e e c o n d i t i o n s of o p e r a t i o n must b e c o n s i d e r e d w i t h r e g a r d t o

*Because of t h i s tendency t o e x i s t i n t h e e l e m e n t a l s t a t e , t h e s e f i s s i o n p r o d u c t s a r e f r e q u e n t l y r e f e r r e d t o as "noble metals" i n MSR's.

7-17

Table 7 . 3 . 2 . 3 . 1 .

D i s t r i b u t i o n of r a d i o n u c l i d e decay heat in a 1000-~(e)MSBR plant Heat g e n e r a t i o n r a t e (MJ)

Location of h e a t s o u r c e

Fuel salt - a l l products

Bubble s t i c k i n g c o e f f i c i e n t = 0.1

Bubble s t i c k i n g c o e f f i c i e n t = 1.0

102

classes of r a d i o a c t i v e

G r a p h i t e i n L"eaLGt0lP Vessel Noble gases amd d a u g h t e r s Noble metal d e p o s i t s

4.8

1.4 3 -6

9.9

1.4

Pletal s u r f a c e s i n primary system -

n o b l e metal deposits Drain-tank system Noble gases and d a u g h t e r s Noble metals and daughters

1.2

9.9 8.3

Off-gas system - noble g a s e s and daughters

2.4

2-4

Fuel reprocessing plant F i s s i o n products Protactinium

6.6 5.0

6.6 5 .Q

To t a l

;

..... ..:.?A

... ....

,&a3

152

release and rmsva%of decay heat; noma1 o p e r a t i o n at v a r i o u s power levels, r e a c t o r shut down b u t fuel s a l t remaining h the primary system, ana r e a c t o r shut CO I WI ~ ~ f u Pe l dfsCkPgeCi E to the drain tank. k i y the last two of t h e s e are re arded as havin p o t e n t i a l s a f e t y s i g n i f i c a n c e . *en the r e a c t o r i s shut elom, t h e radi active decay h e a t d e c r e a s e s w i t h t b e as shorn in P i g . 7 . 3 . 2 . 3 . In a noma1 reactor shutdom, the fuel s a l t is retained i n t h e primary system f o r many h o u r s , the prfmary p m p s c o n t i n u e to o p e r a t e a t f u l l flow on the normal electric supply or at 18% f l o w on pony m o t o r s driven by an emergency power supply, The secondary lso continue t o o p e r a t e a t flows i n t h e r a n e of 10 to loo%, deon the power supply. Heat is t r a n s f e r r e d KBIB t h e pPhBP)y S a l t seconsaary % t e r n is produceti at m c h reduced rates the enerators and f a discharged t o the turbstne condenser o r t o other c o o l e r s . With 10% of t h e i r r a t e d normal f l o w , two p r h a r y Gcsops and a s s o c i a t e d secondary l o o p s w%l1 Bold the temperature a t o r below t h e noma1 level until 5 minutes after shutdown when one l o o p combination i s s u f f i c i e n t . In t h e absence of cooling, t h e t e m p e r a t u r e of the primary system would r i s e t o 1488 and l508"F in 7Q and 128 minutes, respectively. me heat I s a d f f a t h e d r a i n tank begins to deCKease h e d i a t e l y a f t e r SUCh a shutdown. Heat productisn i n the off-gas system decays more slowlly and the h e a t production Ln the processimg p l a n t %B l i t t l e affected for several hours. under a c c i d e n t or o t h e r mu ma^. c i r c ~ s t a n c e sthe f u e l salt i s discharged t o the d r a i n tank f o r cosliing. Discharge of s a l t from the primary system ~ n t othe d r a i n tank could begin a t shutdsm and be e m p i e t e a i n about 7 minutes. at this t h e the heat p r o d u c t i o n rate in t h e d r a i n t a n k would be about 46 'plkb; t h e temperature of the salt would rise t o a m a x h m of 1480°F i n a f e w hours and t h e n fall t o about I O Q O " P i n a f e w days, where i t wsuld b e maintained by c o n t r o l of the cooling. Conditions i n t h e off-gas system and in t h e r e p r o c e s s i n g plant would not be affected s i g n i f i c a n t l y by d r a i n i n g t h e reactor, but the c o n d i t i o n s i n t h e r e a c t o r p r h a r y system would be markedly d i f f e r e n t . D r a i n i n g of the f u e l s a l t would remove t h e fluid t h a t t r a n s p o r t s t h e decay heat f r o m t h e r a p h i t e t o t h e primary heat exchan ers. I f the secondary salt were drained from the heat exchangers at the same time, the preferred means f o r removing the h e a t from t h e decay of noble metal d e p o s i t s on the heat ~ s h a n g e rtubes would a l s o be r a o v e d .

CZdcu%%tiOns have ShOW t h a t the cQlllpOl2entS and P i p i n g %2 t h e pPhaPY s y s p a cotaEd be designed to be cooled adequately by p+svfding a system t h a t would maintain t h e c e l l s walls a t 1600eF. Heat would be t r a n s f e r r e d by r a d i a t i o n and conduction within the components and would be r a d i a t e d t o t h e cell walls. The t: perature at the c e n t e r of the g r a p h i t e c o r e in t h e reactor vease% of the r e f e r e n c e desi n w a s estimated to r e a c h a maximum of 1900°F a f t e r 14 h o u r s , b u t t h e vessel w a l l s would not exceed 1406°F. With sme m o d i f i c a t i o n s of the curreat reference d e s i g n , the center tubes of t h e primary h e a t exchangers would not exceed 2000°F, and the outer s h e l l would n o t tExceed 14005F. Belaying t h e drab by 24 hours and c ~ s l i n gthe p l a n t to H058V during t h a t t h e would reduce the decay heat rates by a f a c t o r of about 10 and would s u b s t a n t i a l l y reduce t h e tmperature rise.

7-19

....

... .... ..... .:*a

...

Fig. 7 . 3 . 2 . 3 . MSBR p l a n t . ... .... T & ,

T h e dependence of decay h e a t sources in a 16400-Mb?(e)

7-20

Release of f i s s i o n p r o d u c t s me p o t e n t i a l release of f i s s i o n p r o d u c t s through m u l t i p l e b a r r i e r s and

t h e i r ultimate dispersPon i n the enviroment i s a major safety consideration i n NSR's as i n any other n u c l e a r system. The processes g ~ v e m i ~ lt g he behavior of f i s s i o n p r o d u c t s in the secondary conta5nment, t h e i r l e a k a g e t o t h e outside, and their dispersion f o r MSR systems are not e x p c t e d to n f f i c a n t l y from those i n other systems. However, behavior i n and releases f r m the p r b a ~ ysystem and t h e primary containment may be q u i t e d i f f e r e n t . The chemical and p h y s i c a l f o m 0 % t h e f i s s i o n products, t h e i r location within the system, and t h e c o n d i t i o n s resulting from accidents all may b e expected t o affect f i s s i o n - p r o d u c t releases.

I ,

The f i s s i o n p r o d u c t s t h a t are h p o ~ t a n tfrom a r a d i o l o g i c a l , o r release, s t a n d p o i n t are not n e c e s s a r i l y those that are most s i g n i f i c a n t in afterh a a t COnsiderat$UnS. FQH. afterheat, allb f i s s i o n pffoducts With significant decay energy are important, while f o r r a d i o l o g i c a l s a f e t y , t h e emphasis is on a more select group of biologically h p o ~ t a n e r: a d i o n u c l i d e s . F u r purposes of o r i @ n t a t f o n , Table 7 . % . 2 . 3 . 2 gives the c a l c u l a t e d hv@fatories of some r a d i o l o g i c a l l y important n u c l i d e s ( i n c l u d i n g a c t i n i d e s ) i n a MSBlfZ SySeeHn and E%% and W B R Systems Of CQmparab]le Size. 'kke MSBR inv e n t o r i e s are given j u s t p r i o r t o shipment of h i g h - l e v e l waste to a federal repository while the PWR and LNFBR invent~riesare given j u s t prior t o refueling. It i s important t o n o t e the e f f e c t of c ~ n t i ~ u o u s processing OR the i n - r e a c t o r i n v e n t o r i e s for an MSBR, as t h e s e are the inventaspies that would n m i n a l l y be a v a i l a b l e f o r release d u r i n g a reactor accident. The h v e ~ t o r i @associated s ~ 5 t hthe p r o c e s s i n g p l a n t and o n - s i t e s t o r a g e f a c i l i t i e s may n o t be ignored, b u t , because of t h e i r i s o l a t i o n f r o m t h e Keaetor, separate c o n s i d e r a t i o n mst be given t o t h e d i f f e r e n t a c c i d e n t s t h a t c o u l d l e a d t o t h e i r release. May radfsnucLides, ineluding suck r a d i o l o g i c a l l y b p ~ ~ t a snpte c i e s as ea, SI-, and I , exist i~ s t a b l e i o n i c foms i n MSBR f u e l s a l t and, t h e r e f o r e , tend t o remain in t h e salt even under u p s e t c o n d i t i o n s . However, i t is also necessary t o kenow their b e h a v i o r mder h i g h l y abnormal conditions where the s a l t may be s u b j e c t t o h y d r o l y s i s o r t o v e r y h i g h t~%~pe~ature~..

Another class of f i s s i o n p r o d u c t s , i n c l u d i n g t h e noble gases9 i s highly v o l a t i l e under MSR conditions and will tend t o be found in t h e off-gas system where release c o n s i d e r a t i o n s again d i f f e r from those 5n the p ~ i mary system. Daughters 0% the v s l a t i b e n u c l i d e s , even though some O f them may tend t o dissolve in s a l t , will g e n e r a l l y appear in t h e off-gas systemS also. The mounts of 6 s and SK t h a t lodge in t h e off-gas system dl1 dE?pencf O n preCUrsQK half lives and the rates of pP632U-PSOH KmoVal.

Yet a n o t h e r class of f i s s i o n p r o d u c t s , the n o b l e metals, are found in t h e elemental state throughout the r e a c t o r p l a n t . Their importance from the s t a n d p o i n t of activity release a ~ i s e sfrom t h e f a c t t h a t some, Bike teablurim, have important, volatile d a u g h t e r s ( i o d i n e , in th%s case). mu%,t h e release c h a r a c t e r i s t i c s sf deposited f i s s i o n p r o d u c t s must also be considered i n s a f e t y studies.

.... c.2.;

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Table 7 . 3 . 2 . 3 . 2 . Comparison of maximum r a d i o n u c l i d e inventories in 1088-Mw(e9 MSBR, PWR, and M F B R power s t a t i o m Inventory (curies)

PWRb

Nuelbide

LMBK'

Reactor

Proces sFng plant

8 %r

1.25

2.8 x 1 0 6

6.4 x 10s

3.2 x 105

90Sr

1.2 x 105

2.9 x I O 7

4 . 3 x 106

1 . 3 x 106

1311

2.4 x 10'

3.5 x I O 7

7 . 2 x 10'

8.2 x 107

1331

9.7 x 1 0 7

1.5 x I O 7

1.3 x IO8

1.2 x 1 0 8

3Xe

7.8 x 103

1.1 x 108

1 . 3 x 188

1.5 x IO8

2 3 3Pa

4.2 x POs

1.6 x 1 0 3 1.6 x 109

3.2 x 109

2 3 9Np

3 . 6 x 1103

2.6 x 1 0 5

2.8 x 105

7 . 1 x 10s

239Pu

0.2

2 . 3 x LO4

1.4 x I O 5

24QPu

0.02

1.2

3 . 3 x go4

1.7 x PO5

24 l f i

0.45

7 . 1 x 106

2.3 x I O 7

24 l b

1.1 x 1Q4

4.0 x I O 4

2 4 3a,

1.2 x 103

1.3 x 104

2.8 x 106

2 . 2 x 106

1.6 x PO5

3.1 x 104

2 3 8Pu

7-22

Engineered s a f e t y %eatures

7.3.3

Status

Advances in t h e area of reactor technology, i n general, and the work i n the and MSR programs at L have provided much of t h e i n f o m a t i o n needed to d a s r a s t r a t e the safety of MSR’s. None of the work, to date, has indicated any s a f e t y issues t h a t cannot be resolved with existing techns%ogy. Rmrever, MSW s a f e t y technology and t h e i s s u e s t h a t are S p e c i f i c to t h i s r @ a C t Q K cCKlcept have not beell SUbjected to t h e COTllprehensive a n a l y s i s and assessment that have been a p p l i e d to other reactor concepts. Consequently, the safety ssurance of M S W B s is less firmly founded ana additional t e c ~ a n o i o deVelOplllenk: is KeqUfTXd tO d@EtOnstrate clearly t h e safety of these r ctor systems. The foHl~wi raphs s m a r i z e briefly the c u r r e n t s t a t u s of M% s a f e t y techno

7-23

9.3.3.1

...

Accident a n a l y s i s

From t h e foregoing background diseussisn of bgSR s a f e t y , it 1s a p p a r e n t t h a t many p o s t u l a t e d accident sequences have been a an tined f o r m o l t e n - s a l t systms. In g e n e r a l , these s t u d i e s have shown t h a t none of the p o s t u l a t e d sequences i s l i k e l y t o b a d t o u n a c c e p t a b l e consequences. However, the e n t i r e spectrum of accfdents has not been exmtned i n sufficient d e t a i l t o e n s u r e t h a t no high-risk events have been n e g l e c t e d . Nor have t h e postulated e v e n t s been tho~oughkgrs o r t e d o u t frm the s t a n d p o i n t 0% r i s k . CsnseqnentPy, f u r t h e r a c c i d e n t a n a l y s e s are r e q u i r e d to define needs and p r o v i d e guidance f o r a d e I i t i ~ ~ ts % a f e t y technology development. The methods and t o o l s r e q u i r e d f o r such analyses are, f o r t h e most p a r t , , a v a i l a b l e w i t h i n t h e g e n e r a l area of r e a c t o r teclaaz~logy. H Q W ~ V ~i t~ will be n e c e s s a r y t o g e n e r a t e comprehensive system models QE MSR systems t h a t w i l l ~ I ~ OaV c cJu r a t e e v a l u a t i o n s sf s a f e t y - s i g n i f i c a n t e v e n t s by a d e q u a t e l y d e s c r i b i n g all sf t h e important p l a n t p r o c e s s e s , i n c l u d i n g t h o s e which are p e c u l i a r to MSR's.

7.3.3.2

F i s s i o n product behavior

The g e n e r a l b e h a v i o r sf f i s s i o n p r o d u c t s i n m o l t e n - s a l t systems h a s been l a r g e l y e s t a b l i s h e d by a v a r i e t y of independent s t u d i e s and by analyses of t h e M S X perfomance, b o t h during and after i t s o p e r a t i o n . As t h e noble-gas f i s s i o n p r o d u c t s (xenon and k ~ p t o n )were r e a d i l y f r m the c i r c u l a t i n g f l u i d and t r a n s p o r t e d t o the off-gas systen. Although there was s i g n i f i c a n t transport of these materials t o t h e unsealed graphite used i n t h e MSWE, a factor of 6 r e d u c t i o n i n xenon pofsoning was achieved wtth a simple g a s - s t r i p p i n g system. Once K ~ I P ~ O V t~h~e ,s e gases could be e f f e c t i v e l y and p r e d i c t a b l y handled i n t h e off-gas t r e a t m e n t f a c i l i t y . Post-shutdom release of gases p r e v i o u s l y held up on t h e g r a p h i t e m y , however, be a r a d i o l ~ g i ~ as al f e t y c o n s i d e r a t i o n in t h e pr an MSBW.

.:.e

..&

I n t h e MSRE, a t l e a s t some of t h e noble-gas d a u g h t e r s famed i n t h e o f f gas system ~ t carried ~ e along by the gas strean, and l a r g e q u a n t i t i e s were a c c m u l a t e d i n t h e p a r t i c l e t r a p s u p s t r e m of the c h a r c o a l b e d s , S i n c e the off-gas had no f u r t h e r exposure t o t h e f u e l s a l t , no i n f o m a tisn w a s o b t a i n e d w i t h r e s p e c t t o r e d i s s o l u t i o n in t h e salt, which could be bport8nt in the EgSBW d r a i n t a n k .

The fission ~ K O ~ U Ct h~ aSt , from themody~lawiec o n s i d e r a t i o n s , were exp e c t e d t o remain d i s s o l v e d i n t h e f u e l salt w e r e shorn i n t h e HSRE t o behave as expected. Among t h e s p e c i e s of p a r t i c u l a r t n t e r e s t from a icaP safety s t a n d p o i n t , b o t h i o d i n e and strontium showed no tendency t o escape fron the salt. Sme i o d i n e d i d appear i n t h e gas in the r e a c t o r Poop a f t e r s a l t : d r a i n s , due t o decay of p r e c u r s o r s t h a t had been depos5ted on system surfaces. n e s a f e t y consequenees of such releases f ~ a~n MSBR, m both during accidents and during maintenance, must be examined. Many of the noble-metal f i s s i o n p r o d u c t s were found ow surfaces i n t h e MSRE. I f t h e a p p a r e n t s t i c k i n g c o e f f i c i e n t of n o b l e metal a t m s t o metab s u r f a c e s i s taken as 1.8, t h e n data from the MSRE

7-24

i n d i c a t e that t h e a p p a r e n t s t i c k i n g c o e f f i c i e n t t o g r a p h i t e w a s 0.5-1.0 and t o g a s bubbles w a s <0.1. I t i s n o t clear whether t h e s t i c k i n g eoe f f i c i e n t t o t h e bubbles w a s l o w because t h e m e t a l p a r t i c l e s d i d n o t remain on the i n t e r f a c e s a s t h e b u b b l e s c i r c u l a t e d i n the p r h a r y system o r because t h e m e t a l p a r t i c l e s , a f t e r b e i n g r e l e a s e d i n t h e pump bowl by t h e bubbles, were resuspended i n t h e l i q u i d and r e t u r n e d t o t h e primary system. %is l a c k of c o n c l u s i v e d a t a on n o b l e - m e t a l behavior l e d t o t h e range of d i s t r i b u t i o n s p r o j e c t e d f o r t h e MSBR. Unless d a t a are o b t a i n e d from o t h e r s o u r c e s t o permit b e t t e r d e f i n i t i o n of t h e d i s t r i b u t i o n , t h e n e x t m o l t e n - s a l t r e a c t o r w i l l have t o b e designed t o d e a l w i t h a substant i a l r a n g e of noble-metal d i s t r i b u t i o n s The p r i n c i p a l s a f e t y considerat i o n w i t h t h e s e materials and their d a u g h t e r s i s e n s u r i n g t h a t t h e h e a t produced by t h e i r d:xxiy does n o t adversely a f f e c t the i n t e g r i t y of t h e primary system ~ o ~ p o n e on ~ ~which ts they are deposited. The behavior of t r i t i u m i n m o l t e n - s a l t s y s t e m i s n o t y e t w e l l unders t o o d . Although t h e c o n t r o l and h a n d l i n g of t h i s material i s n o t a s a f e t y c o n s i d e r a t i o n per % e , the i n v e n t o r y and d i s t r i b u t i o n of t r i t i u m must b e c o n s i d e r e d in e v a l u a t i n g t h e release of r a d i o n u e l i d e s d u r i n g a c c i d e n t s . I n a d d i t i o n , any a c c i d e n t - r e l a t e d v a r i a t i o n s i n t r i t i u m behavior must b e w e l l known and p r o t e c t e d a g a i n s t .

7.3.3.3

P r P m r y system materials

b..

The area of materials technology f o r m o l t e n - s a l t r e a c t o r s i s n o t yet f u l l y developed, a s i n d i c a t e d i n o t h e r portions of t h i s program p l a n e Xuch of t h e s a f e t y and s a f e t y - r e l a t e d technology of s t ~ u c t ~ rmaterials, d g r a p h i t e , and s a l t s w i l l b e developed i n c o n j u n c t i o n w i t h t h e e f f o r t s Pn t h e s e other areas. From the i n f o r m a t i o n t h a t i s now a v a i l a b l e , i t does n o t appear t h a t s a f e t y c o n s i d e r a t i o n s w i l l s i g n i f i c a n t l y a f f e c t t h e choices of or t h e performance r e q u i r e m e n t s on primary system materials. b h i l e a d d i t i o n a l q u a n t i t a t i v e d a t a on f a i l u r e limits, f a i l u r e modes, and i n t e r a c t i o n s under a c c i d e n t c o n d i t i o n s w P l l b e needed f o r t h e det a i l e d e v a l u a t i o n of a c c i d e n t sequertces and c ~ n s e q u e ~ ~ tehse, materials t h a t m e e t t h e requirements f o r normal o p e r a t i o n and a n t i c i p a t e d t r a n s i e n t s will have s u i t a b l e s a f e t y c h a r a c t e r i s t i c s .

e..!

S u b s t a n t i a l e f f o r t has gone i n t o t h e development o f MSR components b u t muck nore remains t o b e clone, p a r t i c u l a r l y w i t h r e s p e c t t o components on which m o l t e n - s a l t service impuses s p e c i a l requirements (e.g., steam g e n e r a t o r s and v a l v e s ) . %iowever, as i n t h e case of materials technology, much of t h e s a f e t y and s a f e t y - r e l a t e d i n f o r m a t i o n w i l l follow from t h e b a s i c development e f f o r t . Among t h e item of p a r t i c u l a r i n t e r e s t with r e g a r d t o s a f e t y are the containment and t h e p r o v i s i o n s for a f t e r h e a t removal e

The ultimate r e l i a c e f o r p r o t e c t i o n of t h e p u b l i c from an MSBR a c c i d e n t r e s t s on the containment system that i s i n e f f e c t d u r i n g o p e ~ a t i ~ n s .

.... I’i>..

7-25

T h i s system does n o t i n v o l v e any u n t r i e d c o n s t r u c t i o n t e c h n i q u e s . me i n n e r w a l l s of t h e r e a c t o r c e l l and t h e f u e l s a l t d r a i n t a n k c e l l must b e i n s u l a t e d and khe c e l l s must b e h e a t e d and operated a t temperatures above 1060°F, 'Phe requirements f o r t h i s system o u t t o and i n c l u d i n g t h e cell l i n e r and l i n e r c o o l i n g s y s t e m are very s i m i l a r to t h o s e imposed on the i n t e r n a l p o r t i o n s of t h e PCRV's used f o r HTGR's. However, because of the lower d e s i g n p r e s s u r e s involved in FER containments, it i s not expected t h a t p r e s t r e s s i n g of t h e c o n c r e t e vessels ( c e l l s ) w i l l b e req u i r e d . A s p o i n t e d o u t earlier, t h e c h a r a c t e r i s t i c s of MSBR f l u i d s impose no severe problem w i t h regardl t o p r e s s u r i z a t i o n o r danger of chemical r e a c t i o n s . T h e r e f o r e , W E R c e l l s and b u i l d i n g s can b e mostly designed and b u i l t w i t h t h e containment technology t h a t has been thoroughly developed f o r o t h e r r e a c t o r s . I n o r d e r t o p r e v e n t p o t e n t i a l l y hazardous releases of r a d i o a c t i v i t y t o t h e environment d u r i n g r o u t i n e maintenance, as well as d u r i n g a c c i d e n t recovery o p e r a t i o n s , i t w i l l b e n e c e s s a r y t o p r o v i d e s p e c i a l d e v i c e s and c l o s e d v e n t i l a t i o n s y s t e m when t h e containment i s opened. Some e x p e r i e n c e w a s accumulated a l o n g these Pines i n t h e o p e r a t i o n of t h e MSRE, b u t on a much smaller scale than w i l l be involved w i t h t h e l a r g e r MSBR system. This technology w i l l have t o b e expanded t o MSER scale. The technology a s s o c i a t e d w i t h secondary containment i s e s s e n t i a l l y t h e same as f o r a l l o t h e r r e a c t o r containment systems.

The p r o v i s i o n of shutdown c o o l i n g i n an MSBR h a s as many f a c e t s as t h e r e r e p o s i t o r i e s f o r t h e f i s s i o n p r o d u c t s . However, o n l y the cooling of t h e f u e l s a l t i n the d r a i n tank appears t o b e a s i g n i f i c a n t s a f e t y cons i d e r a t i o n . P r e l i m i n a r y s t u d i e s i n d i c a t e t h a t a n a t u r a l convection c o o l i n g system w i l l p r o v i d e t h e c o o l i n g r e q u i r e d f o r s a f e t y .

7.3.3.5

I n s t r u m e n t a t i o n and c ~ ~ ~ t r o l s

N o d e t a i l e d s t u d i e s have y e t been performed t o d e f i n e t h e s p e c i a l needs for safety i n s t r u m e n t a t i o n and c o n t r o l s i n M%ER's. However, t h e postu-

l a t e d a c c i d e n t s t h a t have been examined do not appear t o impose any requirements beyond those needed f o r normal, s a f e o p e r a t i o n .

7.3.3.6 ,.&

Maintenance

The maintenance of m o l t e n - s a l t r e a c t o r s , even under noma1 circumstances, promises t o b e a c h a l l e n g i n g task. A number of techniques and procedures were developed and demonstrated in t h e MSM and some o f t h e s e w i l l , w i t h f u r t h e r development, b e a p p l i c a b l e t o l a r g e r systems. However, a d d i t i o n a l p r o c e d u r e s , such as t h o s e for completely semi-remote c u t t i n g , c l e a n i n g , and welding of l a r g e - d i a m e t e r p i p e s must be developed f o r r o u t i n e m i n t & name, as w e l l as f o r recovery from accidents. Preliminary studies have i n d i c a t e d no major d i f f e r e n c e s between t h e requirements f o r normal maintenance operations and t h o s e associated w i t h major a c c i d e n t s . S i m i l a r l y ,

7-26

inspection t e c h i q u e s and proeeaures that are developed f o r n o m a l , inservice i n s p e c t i o n s are expected t o be a p p l i c a b l e to s a f e t y s i t u a t i o n s . speeiaa. safety p r o b ~ a sassoeiatea with maintenance will be addPessea they are uncovered by the d e v e l o g ~ ~ e nptr o

7'3.3.7 No s i g n i f i c a n t effort has y e t been made to i d e n t i f y s p e c i a l s a f e t y p r o b l e m related to these o p e ~ a t i o n sin MSR systems. These areas will be addressed as the system feckslslsgy i s developed.

7,4

7-4.2

TASK GROUP 6.1

k . .

GUIDANCE STUDIES

SsheduPe and funding

The proposed s c h e d u l e of e f f o r t fop. t h e s t u d i e s to provide the s a f e t y P K O ~ Pi s~ shown sch@aaatiea%Pyi n Table 7.4.2.1. For the p r i n c i p a l tasks, a c o n t i n u i n g e f f o r t i s m i n t a i ~ e dthroughout the program ts e 9 ~ ~ 1 -teh e a v a i l a b i l i t y of c u r r e n t r e s u l t s r e g a r d i n g a c c i d e n t progressions and consequences for s a f e t y assessments and the i d e n t i f i c a t i o n sf tedTAOlogy need§ as they d@veEQp. HOWeVer, t h e levels sf effort, particularly ~ 5 t hregard t o a c c i d e n t a n a l y s i s , vary s u b s t a n t i a l l y . As shown in Table 7 . 4 . 2 . 2 , which shows t h e proposed f u n d i n g f o r this t a s k group, studies ts i d e n t i f y and d e s c ~ i b ea c c i d e n t s and a c c i d e n t sequences r i s e t u higher levels as d e s i g n s f o r c o n c e p t u a l and proposed r e a c t o r systems are evolved. The e f f o ~ ton t r a n s i e n t analyses follows just behind the descriptive a n a l y s e s but ~ 5 t ha similar patte~n. S i n c e these studies are c s n t i n g e n t on the development og reactor desigms, t h e i r thing would change w i t h v a r i a t i o n s i n the o v e r a l l development s c h e d u l e . Risk analyses, being h e a v i l y dependent on t h e a v a i l a b i l i t y of perfomance and r e l i a b i l i t y d a t a f o r components and systems, cannot be pursued a t any substantial level until l a t e r in t h e program. However, some s e m i q u a n t i t a t i v e information can be developed w i t h V ~ K Yl i t t l e i n p u t , so a small e f f o r t idance as can b e w i l l be undertaken early in the program to p ~ o v i d esuch d e r i v e d f+m these a n a l y s e s 0

d.2

h..

Table

6.1-P

7.4.2.1.

Accident et al.

analyeia - Ref. design,

6.1.1-l 6.1.1.2 6.1.1.3

Accident description Accident transient Rieb anafysie

6. I. 2

Technolo~ 6.1.2-l 6.1.2.2

need identification Safety technology Safety-related technology

6 * 1 a3

Analytical

methoda

analyses

schedule

for

work

fn Task Group

6.1 - guidance

studies

Table

Smry

7.4,2.2.

aperating

fund (coets

6.1.11

6.1.2

6.1.3

Aeefdent et al. 6.1.1.1

analysis Accident

Subtotal

6.B.I

Risk

Safety

Subtotal

6.1.2

Analytical

aesePfption transient analysis

need

6.1.2.1. 6.1.2.2

operating

fOK

Task

Group

6,l

Gufdance

studies

dablars)

1976

1977

1978

1979

P980

1981

1982

1983

analyses

70 20

60 83

30 90

20 70

6Q 60

60 B20

150

60 245

20 80 40

143

---14Q

140

120

180

210

30 30 60

20 20 40

2Q 20 40

20 20 40

30 30 -

3Q 233

60 __ 240

60 ----

240

190

1984

1985

360 60

390 60

305

420

450

30 30 -

40 20 _I

60 30 -

60 40 -

mea

120

1QQ

240

360

120 ---390

485

600

650

-----

identification technoPogy

saf@ty--rdacea

technology

methods funds

1QQO

1975

Total

design

Acefdent

g-1.1.2 6.1.1.3

Technology

- Ref.

requirements

fa3r Task Group

6.1

1986

5-29 The development of a n a l y t i c a l methods f o r s a f e t y a n a l y s e s depends f i r s t on t h e i d e n t i f i c a t i o n of needs which have n o t been, and are n o t expected to b e , m e t by e f f o r t s w i t h i n o t h e r technology areas. Although such needs are expected t o arise, p a r t i c u l a r l y i n d e s c r i b i n g she response of t h e e n t i r e p l a n t t o major t r a n s i e n t s , work on t h i s t a s k w i l l n o t b e g i n f a r a few y e a r s .

7.4.3

Facilities

The work in t h i s t a s k group i s e n t i r e l y a n a l y t i c a l i n n a t u r e , s o no exp e r i m e n t a l f a c i l i t i e s are involved. The Parge-scale c~mputingc a p a b i l i t y i m p l i e d by t h e t r a n s i e n t a n a l y s i s t a s k s i s expected t o b e within t h e range o f e x i s t i n g d i g i t a l , analog, and h y b r i d f a c i l i t i e s c u r r e n t l y a v a i l a b l e a t OWE *

7.4.4

Task 6.1.1

Accident a n a l y s i s

S e v e r a l kinds of a c c i d e n t a n a l y s i s , i n i n c r e a s i n g levels of d e t a i l and accuracy, w i l l be perfomed t o provide a b a s i s f o r assessing the s a f e t y of MSRtss. These a n a l y s e s w i l l b e a p p l i e d i n i t i a l l y t o t h e OW ' ESE r e f e r e n c e d e s i g n MSBB t o e s t a b l i s h , as q u a n t i t a t i v e l y as p o s s i b l e , t h e s a f e t y c h a r a c t e r i s t i c s of a r e p r e s e n t a t i v e p l a n t . A s o t h e r c ~ n ~ e p t u ad el s i g n s are developed, they w i l l be s u b j e c t e d t o similar s t u d i e s t o i d e n t i f y any s i g n i f i c a n t v a r i a t i o n s i n s a f e t y c h a r a c t e r i s t i c s or s a f e t y margins. The a n a l y s e s w i l l be made p r o g r e s s i v e l y more d e t a i l e d as t h e d e s i g n s are r e f i n e d , and t h e most d e t a i l e d s t u d i e s w i l l be made on s y s t e m a c t u a l l y proposed f o r c o n s t r u c t i o n .

7.4.4,l ..... .x*

.,.=

iii.,

... .... : $a

Subtask 6.1.1.1

Accident d e s c r i p t i o n s

The i n i t i a l e f f o r t i n the a n a l y s i s sf FER w i l l b e a s y s t e m a t i s , q u a l i t a t i v e d e s c r i p t i o n of p o s s i b l e a c c i d e n t s and event sequertces. Although several i s o l a t e d transienbs have been examined in some d e t a i l and Some a c c i d e n t sequences have been proposed and s t u d i e d , no o r g a n i z e d e f f o r t h a s y e t been m d e t o i d e n t i f y a major fractfon of t h e p o s s i b l e a c c i d e n t s and t h e i n t e r r e l a t i o n s between them. This e f f o r t i s expected t o r e s u l t i n t h e idC%ltificatiQn of a full spectPUUl Of events from I K h S P UpSets to accid e n t s w i t h p o t e n t i a l major s a f e t y s i g n i f i c a n c e . 'Fhe e v e n t s w i l l b e c l a s s i f i e d and c a t e g o r i z e d t o determine s a f e t y s i g n i f -

i c a n c e based on estimates s f t h e l i k e l i h o o d for o c c u r r e n c e , s e v e r i t y 0% consequences, and t o some e x t e n t , a v a i l a b i l i t y of d e f e n s e s a g a i n s t t h e e v e n t s . These c l a s s i f i c a t i o n s w i l l be e s t a b l i s h e d w i t h t h e a i d of v a r i o u s l o g i c a l a n a l y s i s ~ O O P S ,such as event-tree diagrams, which will also h e l p to c l a r i f y i n t e r a c t i o n s among e v e n t s and t o i d e n t i f y a v a i l a b l e and/or needed l i n e s of defense. As additional design i n f o m a t i o n and r e s u l t s of t r a n s i e n t a n a l y s e s become a v a i l a b l e , t h e a c c i d e n t desc~iptions and eventsequence d i a g r a m w i l l b e r e f i n e d to more c l e a r l y and q u a n t i t a t i v e l y des c r i b e t h e n a t u r e and e x t e n t of t h e s a f e t y c o n s i d e r a t i s n s a s s o c i a t e d w i t h each a c c i d e n t a

*g&.

..... .:.... ..:*

7-38 7.4.4.2

Subtask 6.1.1.2

AccPdent t r a n s i e n t a n a l y s e s

R e p r e s e n t a t i v e a c c i d e n t s and e v e n t sequences i d e n t i f i e d i n Subtask 6.L.l.l w i l l b e s u b j e c t e d t o q u a n t i t a t i v e t r a n s i e n t a n a l y s i s to determine the mgnitudes of t h e consequences of such accidents;. me results of t h e s e analyses will b e w e d to i d e n t i f y t h o s e a c c i d e n t s whose s a f e t y s i g n i f i c a n c e qualifies them f o r more d e t a i l e d a n a l y s e s . Later r e s u l t s , , coupled w i t h the l o g i c a l a n a l y s e s , will provide t h e bases e v a l u a t i n g s a f e t y margins as w e l l as for d e f i n i n a d d i t i o n a l technology needs and the needs f o r and p e r f s m m c e requirements of e n g i n e e r e d s a f e t y f e a t u r e s .

7.4.4.3

Subtask 6.1.1.3

Risk a n a l y s i s

me final s t e p i n t h e d e f i n i t i o n sf MSR s a f e t y i s t h e perfomanee o f r i s k a n a l y s e s which e n t a i l the appropriate combination of a c c i d e n t o c c u r r e n c e some q u a l i t a t i v e or$, p r o b a b i l i t i e s w i t h a c c i d e n t c ~ n s e q u ~ ~ ~ cAlthough es. a t b e s t , s e m i q u a n t i t a t i v e a n a l y s e s of t h i s k i n d must b e c a r r i e d out e a r l y ta h e l p s e l e c t t h e %IRpQKtaIta c c i d e n t s , d e f i n f t i v e a n a l y s e s r e q u i r e d a t a concerning component and system performance, r e l i a b % l i t y , and f a i l u r e c h a r a c t e r i s t i e s t h a t will n o t become a v a i l a b l e for some t i m e . Thus,, s t u d i e s sf t h i s kind, which serve primarily t o reduce u n c e r t a i n t i e s i n s a f e t y ?nargins, w i l l c o n t i n u e even beyond t h e o p e r a t i o n of prototypica% and demonstration ~ e a c t o rsystems.

7.4.5

Task 6.1.2

Technolopy need i d e n t i f i c a t i o n

The accuracy of and, i n some cases, even t h e performance of t r a n s i e n t and o t h e r a c c i d e n t a n a l y s e s will b e l i m i t e d by the d a t a t h a t are availa b l e t o d e s c r i b e material, component, sub-system, and system r e s p o n s ~ ~ under a c c i d e n t c o n d i t i o n s . T h i s t a s k p r o v i d e s f o r the i d e n t i f i c a t i o n sf such weeds and t h e i r p u b l i c a t i o n s o t h a t the n e c e s s a r y i n f o m a t i o n can be developed. ~ d d i t i s n atechnology ~ be expected to occur in all t h e MSR t e c h n s h g p areas, and most of them w i l l b e addressed under t h i s task. However, a s e p a r a t e , b u t eomplementarp, need assessment t a s k i s i d e n t i f i e d i n the areas of s a f e t y instrumentation and c o n t r o l s (Task Group 6.5) because of t h e hi hiy- s p e e i a i i z e a EUXI diverse t e c h n i c a l requirements sf such systems. S i n c e t h e need assessment task spans t h e e n t i r e range of r n R technology, t h e work w i l l be shared among a n m b e r of p e o p l e w i t h a p p r o p r i a t e t e c h n i c a l c a p a b i l i t i e s .

In g e n e r a l , it i s expected t h a t b a t h s a f e t y and s a f e t y - r e l a t e d technology needs w i l l b e F d e n t i f i e d by this e f f o r t , and these c a t e g o r i e s are addressed by s e p a r a t e subtasks bebota. %t is assmed t h a t needs which are i d e n t i f i e d and apgrspriabely j u s t i f i e d w i l l be f u l b f l l l e d by efforts i n other p a r t s of t h e overall p r o g r ~ ~ ~ ~

irs.

7-31 7.4.5.1

Subtask 6.1.2.1

Safety technology needs

T h i s subtask i s concerned w i t h the needs for addftionak. t e c b o l s g g assoc i a t e d s p e c i f i c a l l y with the s a f e t y of MSR's. T h a t i s , i t i d e n t i E i e s and j u s t i f i e s those needs which could not reasonably be f u l f i l l e d by a c t i v i ties in base technology areas. I n a d d i t i o n , it will i d e n t i f y weeds t o check o r v e r i f y tec%af%s%ogy developed i n o t h e r areas to ensure i t s applic a b i l i t y t o s a f e t y c o n s i d e r a t i o n s . A s suck, i t i n t e r a c t s m o s t s t r o n g l y d t l a o t h e r task groups i n the area of reactor s a f e t y . M Q W W ~ close ~ ~ c o r r e l a t i o n with base-program a c t t v i t i e s and need assessments i s a l s o r e q u i r e d t o a v o i d non-productive d u p l i c a t i o n of e f f o r t .

This subtask i d e n t i f i e s those technology of data developments which, a l t h o u g h they are needed f o r s a f e t y s t u d i e s , are also needed f o r the d e s i g n and safe o p e r a t i o n of MSR's under more noma1 c o n d i t i o n s . These needs will i n m o s t cases have been recognized and be under deve1opment as a r e s u l t of o t h e r base-program investigations. HoweverPT, t h i s effort w i l l help ensure t h a t no important s a f e t y - r e l a t e d needs are overlbsoked.

7.4.6

Task 6 . 1 . 3

A n a l y t i c a l methods

TT&s task p r o v i d e s for the development of a n a l y t i c a l methods, including computational mode%s, m e t b d s , and programs, wh%ch are needed f o r s a f e t y analyses and which are n o t l i k e l y t o becme a v a i l a b l e from o t h e r sources. Since s a f e t y a n a l y s i s d e a l s with t r a n s i e n t events which are, by d e f i n i t i o n , larger than t h o s e encountered i n s o u t i n e o p e r a t i o n , t h e a n a l y t i c a l tools developed f o r d e s i g n and routine a n a l y s i s may n o t be adequate for s a f e t y work. Among the areas where such i n a d e q u a c i e s may occur are comprehensive models to d e s c r i b e the b e h a v i o r of an e n t i r e p l a n t durFng severe OK r a p i d t r a n s i e n t s and models to descrLbe large nuclear t r a n s i e n t s in circulatingfuel reaetsrs. (The " n e u t r o n i c sizesrof the c o r e may also be a f a c t o r * ) Wherever p o s s i b l e , e x i s t i n g models and methods w i l l be adopted or adapted for s a f e t y studies. S e p a r a t e subtasks w i l l be e s t a b l i s h e d t o m e e t v a r i o u s development needs.

7.5

TASK GROUP 6 . 2

FISSION PRODUCT BEHAVIOR

This t a s k group i s concerned w i t h the d e v e l o p m e ~ tof t h e chemical and physical technology r e q u r r e d for a c c u r a t e d e s c r i p t i o n of t h e behavior of f i s s i o n products i n MSR systems under a c c i d e n t c o n d i t i o n s . While many s a f e t y and s a f e t y - r e l a t e d a s p e c t s of f i s s i o n product b e h a v i o r w i l l be elucidated by base program studies, the unusual conditions t h a t may arise i n some aecidenta 1ikePy & r i l l r e q u i r e t h e h f t i a t i o n 0% s p e c i a l e f f o r t s to o b t a i n d a t a . "he mrk 5n t h i s task group i s d i r e c t e d priraaariPy toward the r e a c t o r p r h a s g system. F i s s i o n product behavior and

... ...., ,.=

7-32 &.L

p s s s i b l e releases asaoc2ated ~ 5 t ha c c i d e n t s i n the waste s t o r a g e facilities and the wore remote p a r t s of the chemical processing system are treated in Task GKSUl, 6 . 7 . 7.5.2

Schedule and funding

Since the i n v e s t i g a t i o n s of f i s s i o n product b e h a v i o ~under t h i s task group are c o n t i n g e n t upon the i d e n t i f i c a t i o n of s a f e t y - s p e c i f i c needs, i t i s n o t a n t i c i p a t e d that a c t i v i t i e s w i l l be supported until a substantial m o u n t of s a f e t y a n a l y s i s Jms been performed. Once t h e limiting c o n d i t i o n s of a c c i d e n t s have been e s t a b l i s h e d , it w i l l be p r a c t i c a l to review the available t e e h a l o g y and the ongoing base program e f f o r t t o detemTne what s a f e t y needs, i f anyp,remain. Work w i l l then be s u p p o ~ t e d t o supply t h o s e needs. 0x1 this basis no a c t i v i t y i s shown on the development of f i s s i o n - p r o d u c t safety technology f o r about ehree years ( s e e Table 7 . 5 . 2 . l ) . Subsequently, the effort is expected to proceed at a r e l a t i v e l y low l e v e l as shmm by the fusdhg schedule (Table 7.5.2.2) because e s s e n t i a l l y all, %f n o t a l l , of t h e technology needs are expected t o be m e t by efforts in the base p k ~ g r a . The technology development t h a t is suppol-ted by the safety P P S ~ Pwill ~ be carried out by t h e staff who are involved tn t h e base program e f f o r t . 7.5.3

.... ..... ~

.... ex.

Facilities

Any tecBBnology development that i s performed under t h i s t a s k group i s

currently expected t o t a k e the f o m of e x t e n s i o n s i n d a t a ranges and inv e s t i g a t i o n s of phenomena which are chemicaPPy and/or p h y s i c a l l y similar to studies i n the base p r o g r m . Consequently, i t i s not a n t i c i p a t e d t h a t new o r r a d i c a l l y d i f f e r e n t f a c i l i t i e s w i l l be required beyond those used i n the b a s i c s t u d i e s . No a d d i t i o n a l f a c i l i t i e s are, t h e r e f o r e , projected. 7.5.4

Task 6 . 2 . 1

Fission p ~ o d u ~ release t under a c c i d e n t c o n d i t i o n s

u . 2

7.5.4.1

Subtask 6.2.1.1

Fission product release from s a l t s

The release characteristics of fission products from fuel s a l t s have been s t u d i e d e x t e n s i v e l y and the n o ma 1 behavior i s moderately well h o r n . A d d i t i o n a l l y , i n f o m a t f o n will be d e ~ e h p e dw i t h i n t h e base program for noma1 and near-normal conditions. This subtask provides for lhfavestigations under s p e c i a l conditions that might r e s u l t if, for a m p l e , the

Table

7.5.2.1.

Schedule

for

work in Task Group 6.2 - Fission

product

Fiscal

year 19 80

6.2.1

Fission product release under accident conditions 6.2.1.P FP release frsm salts 6.2.1.2 Fp release from metal surfaces 6.2.1.3 FP release from graphite 6.2.1.4 Fp release from failed charcoal. bed

6.2.2

Tritium release conditions

under

accident

6.2.3

Fission product behavior and secondary containment

in primary

behavior

--._“. ----

1983

1984

-45

30 4.5

Fission paPaductbehavior in primary merit

and

secondary

csntain-

I.5 45

45 45

7-35

7.5.4.2

Subtask 6.2.1.2

Fission product release from metal s u r f a c e s

F i s s i o n product releases from MSR metal surfaces, both w i t h and without s a l t present, has ~ e c e i ~ esome d attention b u t more s t u d i e s are required in the base p r ~ g % a .This process is particularly h p ~ r t a ft a r m a h t e nance o p e r a t i o n s because d e p o s i t e d tellurium can b e a s o u r c e sf f r e e i o d i n e . From the s t a n d p o i n t of safety, releases from overheated surf a c e s o r when the containment atmosphere i s less w e l l c o n t r o l l e d than for noma% maintenance m y r e q u i r e s p e c i a l investigation. 7.5.4.3

Subtask 6 . 2 . 1 . 3

F i s s i o n product release f r o m graphite

t r a p p e a in and on g r a p h i t e m y be subject to d i f f e r e n t release p r o c e s s e s when t h e g r a p h i t e is strongly heated O F exposed t o contaminants d u r i n g aecfdents. If suck processes are shown to have t h e p o t e n t i a l for altering the safety ~ h a r a ~ t e ~ - i s tof i c sMSB systems, they w i l l be i n v e s t i g a t e d and e v a l u a t e d . P ~ S S ~ O Zp-rIo d u c t s

Although the charcoal absorber beds for r e t e n t i o n of noble-gas f i s s i o n p r o d u c t s are not an i n t e g r a l p a r t of t h e r e a c t o r p r i m a r y system, they are suffFeiently c l o s e l y coupled t o i t t h a t failure could l e a d to a release of fission p r o d u c t s i n t o t h e primary containmnt. me high fissionp ~ s d u c ti n ~ e ~ l of t ~these v beds mkes i t diesirable to examine t h e i r potent i a l effect on s a f e t y . Welease p r o c e s s e s t h a t are p e c u l i a r t o reactor a c c i d e n t c o n d i t i o n s would have to b e d e f i n e d before studfes are i n i t i a t e d . 7.5.5

Task 4.2.2

T r i t i u m release u ~ l d ea c~c i d e n t conditions

Depending upon t h e nature of t h e t r i t i u m r e t e n t i ~ nand c s n t ~ o % processes that are developed f o r MSX~S,e i t h e r o r b o t h t h e primary and secondaq s y s t e m may c o n t a i n s u b s t a n t i a l q u a n t i t i e s of this r a d i o n u c l i d e . It i s considered s e p a r a t e l y h e r e because its behavior mechanisms d f f f e r signdfi~ m t l yfrom those of other f i s s i o ~ n - p r o d ~r~a d t i o n ~ c l i d e sand because t h e tritium h a n d l i n g t e ~ h n o fl o~r MSR's ~ is a s e p a r a t e problem. U n t i l the t ~ i t i ~technology m i s developed f u r t h e r i t will not be practical t o ident i f y any s p e c i f i c i n v e s t i g a t i o n s i n t o s a f e t y problems $n t h i s task. However, such studies will b e CBPFi@d o u t when, and i f , needs are i d e n t i f i e d .

.... .... . &

/.& ...

.... i

7-36 7.5.6

Task 6 . 2 . 3 Fission-product behavior in primary and secondary contafmats

safety technology of fission-product behavior within containments has been extensively studied in connection wfth other reactor types, and a p p ~ c a b l ep o r t i o n s of t b t t e c h o ~ o g ywz1.1 be used 5x1 MSR safety Studhs. &FEv@pg the f u t a d a a t a l d$fferenc@s betW%?n MSR's 2LX-d other reactors could lead to d i f f e r e n t e l i a i c a l and physi~alf o m s and mixtures of fission p r s & e t s 2n the containment a f t e r an accident. Smdies should be performed to d e t e m h e whether such differences QCCW and if they significantly affect Qeitber favorably or unfmorably) the in-containment behavior of the radionuclides. If differences are found, t h e i r h p a c t on reactor safety should be evaluated.

7.6.2

Objective

The i n t e r a c t i o n s , responses, and failure modes of primary-system materials under accident c s n d i t i o n e must be llsflown if detaFEed safety analysis are to be carrEed out. The objective sf the work 5n t h i s task group is the qrrantitatfve establishment of any such safety-sfgniffeant processes and p r o p e r t i e s that are not e s t a b l i s h e d in base-p%ogfm h v e s t i g a t i o n s e

The. investigation of material properties and interaction processes requires first t b t the parmeter ranges t b t a m peculiar to safety be i d e n t i f i e d by extensive analysis of accidents and event sequences Consequently the schedule for this task group (Table 7.6.2.1) shows no a c t i v i t y fox- three to four years. The schedule beyond t h a t point is also Pze b@CElUse of the Strong p Q S S i b f l i t y %hat aac%st of the required safety technology ~2131probably be developed by r n f n ~ rextensions of estalilished base % e c h o l o g y tasks. The funding (Table 7.6.2.2) is p r o j e c t e d at. a low level f o r the same reason. e

7.6.3

Facilities

As is the case in the other safety-technology task g o u p s , no special facilSty needs are projected because the same facilities used f o r the related base program effort are presumed to be usable and avaflabfe for t h i s work. 7.6.4

Task 6.3.1

Materials c m p a t i b i l i t y under accident conditions

k<.

Table 7.6.2.1.

Schedule for work in Task Group 6.3 - Primary

1977 6.3.1

Materials accident 6.3.1.1 6.3.1.2 6.3.1.3 4.3.1.4

compatibility under conditions Primary-to-secondary salt Salt to graphite Salt to metal Salt to drain-tank coolant

6.3.2

Metal

failure

6.3.3

Graphite failure properties

es3.r,

Salt behavior csnditisns

modes and properties

year

1978

- - I_ ---

!E II-

modes and at extreme

Fiscal

system materials

. -I

Materials accident 6.3.lL.l

compatibility csnditions PPilmry-to-secondary salt

6.3.1.2 6.3.1.3 6.?%.1.4

Salt Salt Salt

under

20 20

to gra.pbi.te ts metal tc3 dKain-tank

CQQl~~t

Subtatal

6.3.1

1Q 20 10

20 50

30 38

50 30 -

20 -

7-39

or unusual interactions t h a t may b e associated w i t h a c c i d e n t s w i l l be i n v e s t i g a t e d i n this task. Some of the areas i n which such i n v e s t i g a t i o n s may b e c a r r i e d o u t , s u b j e c t t o need i d e n t i f i c a t i o n , a r e d i s e u s s e d i n the foP1OWing f Q U r Subtasks

This s u b t a s k w i l l i n v e s t i g a t e p r i m a r i l y any ~ u s u a Pe f f e c t s assocPated w i t h mixing of fuel and c o o l a n t s a l t s i n amounts and at rates which are much g r e a t e r t h a n would o r d i n a r i l y be a n t i c i p a t e d . A t t h e more severe c o n d i t i o n s ( s t i n to b e d e f i n e d ) experienced in accidents, d p a i c or t r a n s i e n t phenomena may have an e f f e c t on s a f e t y consequences and these w i l l b e ~ X Z S R ~ RThe ~ ~ .s t u d i e s will b e esnftned t o salt mixtures whose use i n MSR's i s r a t h e r firmly e s t a b l i s h e d .

7.6.4.2 ....

P o s s i b l e unusual interast2on.s between salts and g r a p h i t e under a c c i d e n t conditisns w i l l b e examined t o determine t h e i r s a f e t y csnsequences, if any. Among t h e phenomena t o be c o n s i d e r e d , subject t o e s t a b l i s h m e n t of need, are s a l t boiling n e a r graphite and e f f e c t s of vapors produced by such boiling. A d d i t i o n a l p r o c e s s e s may be i d e n t i f i e d by a c c i d e n t analyses.

9.6.4.3

.... w

Subtask 6.3.1.3

Salt-metal

sampattbtlitg

I n t e r a c t i o n s between s a l t s , or s a l t v a p o r s 9 and primary-system metals under acciclemt c o n d i t i o n s , such as very h i g h t e m p e r a t u r e s , will b e inv e s t i g a t e d and e v a l u a t e d f o r p o s s i b l e s a f e t y consequences. Only t h o s e c o ~ ~ ~ i twisa i ~ nbse c o n ~ i d e r e dt h a t are Rot addressed in base-program studies s

N o p r ~ ~ e s s eo sr mechanisms can be c u r r e n t l y idemtified t h a t would not b e e v a l u a t e d f o r normal o p e r a t i o n and a n t i c i p a t a b l e t r a n s i e n t c o n d i t i o n s . If p r ~ c e s s e sw i t h p o t e n t i a l safety s i g n i f i c a n c e are su gested by a c c i d e n t a n a l y s e s , they will b e s t u d i e d .

.:.>.... A

.... . :.a

.... 3 s

1Llsis task p r o v i d e s ~ Q iPn v e s t i g a t i o n s of metal p r o p e r t i e s i n parameter ranges t h a t m y be associated w f t h a c c i d e n t s , but which would not o t h e r w i s e b e ~ e ~ p i ~ eOdf .p a r t i c u l a r i n t e r e s t are p r o p e ~ t t e s ,b e h a v i o r , and f a i l u r e mdes sf metals exposed to v e r y h i g h temperatures because of their p o t e n t i a l e f f e c t s on t h e consequences of long-term l o s s of c o o l i n g situations.

7-40 7.6-6

Task 6 . 3 . 3

G r a p h i t e p r o p e r t i e s and f a i l u r e modes

Graphite c h a r a c t e r i s t i c s and p o s s i b l e f a i l u r e modes under extreme con-= ditions of thermal c y c l i n g or thermal shock should be exmined f o r pses i b l e e f f e c t s on r e a c t o r s a f e t y . Probably t h e most s i g n i f i c a n t safety c o n s i d e r a t i o n is that s m e degree of s t r u c t u r a l h t e g r i t y be maintained h the graphite naoderator, but the i n t e g r i t y requirements have not been determined. Since MSR g r a p h i t e t e m p e r a t u r e s i n severe a c c i d e n t s are a t least somewhat s 2 m i l a ~to those c a l c u l a t e d f o r HTGR's, it may be p o s s i b l e to Bn&@ U S e Of 80El.e a s p e c t s Qf a p h i t e s a f e t y t e c b o l o g y frm HTGR studies 0

Some c o n s i d e r a t i o n should be g i v e n ts t h e s a f e t y a s p e c t s of s a l t b e h a v i o r a t extreme temperatures o r i n the p r e s e n c e of contaminants that may be h t r o d u c e d by a c c i d e n t s . Vapor m d l i q u i d compositions that result from b o i l i n g , as w e l l as p o s s i b l e solid-phase s e p a r a t i o n s , would b e exmined if a c c i d e n t s t u d i e s showed p o t e n t i a l safety e f f e c t .

7 7 a G

Obj ectives

T E s t a s k group is devoted to the i n v e s t i g a t i o n of s a f e t y s i g n i f i c a n t processes, i n c l u d i n g f a i l u r e , that may a f f e c t m a j o r cmponents and systems in an MSW p l a n t . The primary coneern i s w i t h major safety systems, such as c o n t a i m e n t , and hQ€LLy abnormal p r o c e s s e s s such as seismic events, but o t h e r components, systems, and processes m y be consider@d if s a f e t y needs are i d e n t i f i e d . n e o b j e c t i v e sf t h i s work is to c%everop t h o s e a s p e c t s sf she r e l e v a n t technolo i e s t h a t will h e l p t o d e f i n e and evaluate t h e s a f e t y consequences of a c c i d e n t s .

7.7.2

Schedule and funding

D e v e l o p e n t of cmponent and system technology r e q u i r e s t h a t the eonclitiofas and perfommce b - e ~ p i r r n e n t sl i k e l y t o be b p o s e d on t h o s e systems by p o s t u l a t e d a c c i d e n t s be c l e a r l y d e f i n e d by a c c i d e n t a n a l y s e s . Such analyses, in t u r n , ~ e ~ p t h i a~t e reasonably d e t a i l e d r e a c t o r - s y s t e m conc e p t u a l d e s i g n s be a v a i l a b l e . Consequently, t h e major e f f o r t under t h i s roup$,as shown i n Table 7.7.2.1, b e g i n s a f t e r the development of the weeded d e s i g n i n f o tian. Some of t h e more r e a d i l y a p p a r e n t needs can b e i d e n t i f i e d from s t u d i e s of cunefat c o n c e p t u a l d e s i g n s , so a small m o u n t of work can be started earlier. Table 7.7.2.2 shows t h e estimated level of e f f o r t r e q u i r e d %or s t u d i e s of c u r r e n t l y recognized s a f e t y q u e s t i o n s . Since these studies are s t r o n g l y dependent on t h e d e g r e e of y development under base programs1 t h e mounts t e n d to b e SQIW&at speculative.

.... ..... <.E,

Table

7.7.2.1.

Schedule

far

work

in Task Group 6.4 - Component (accident sondftions) Fiscal

and systems

technology

year 1986

6.4 .l

Cmtaiment systems 6.4.1.1 Effects of salt spills - short term 6.4.1.2 Long-term effects of salt-spill residues

6.4.2

Seismic and vlbratfon technology 6.4.2.1 Failures of primarysystm components 6.4.2.2 Failures af engineered safety features

6.4.1

Contaiment 6.4.1.%

6.4.1.2

Subtstd 6.4 # 2

systems Effects rsf salt spills - SbBQpG term Long-term effects of salt-spill Ice.9 idues 6.4-l

Seismic ana vibration teshncpls~ 6.4.2.9. Failures af primry-system companents 6.4e2.2 Failures of engineered safety features Subtotal

6.4.2

Total operating Group 6.4

funds

fQP

Task

36 60

20 50

PO5

125

-4 P N

-----_n_ 60 _w----

3-l

lQ5

125

12%

165

210

250

25Q

120

168

165

210

250

7-43 7.7.3

Facilities

Major f a c i l i t i e s will. b e r e q u i r e d f o r development o f t h e base technology f o r MSR components and systems (see S e c t i o n I S ) and i t i s expected t h a t t h o s e f a c i l i t i e s will b e s u i t a b l e and available f o r s t u d i e s of s a f e t y technology. One p o s s i b l e e x c e p t i o n t o this s i t u a t i o n i s in t h e area of seismic studies. I f t h e guidance s t u d i e s reveal a weed f o r a seismic program t h a t i s s p e c i f i c to MSR's, and n o t s a t i s f i e d by o t h e r s e i s m i c s t u d y e f f o r t s , s p e c i a l s e i s m i c f a c i l i t i e s might b e r e q u i r e d . S i n c e no s p e c i a l needs a r e c u ~ r e n t l yrecognized o r a n t i c i p a t e d , no f a c i l i t i e s are p r o j e c t e d f o r t h e work; i n this t a s k group.

7.7.4

Task 6 . 4 . 1

Containment systems

Because t h e materials t o be c o n t a i n e d as a consequence of MSR a c c i d e n t s may d i f f e r from t h e materials of i n t e r e s t i n o t h e r r e a c t o r s y s t e m , some s a f e t y s t u d i e s of MSR containments should be made. These s t u d i e s would b e expected t o d e l i n e a t e any unique requirements f o r o r p r o p e r t i e s of these containments. The f o l l o ~ i n gf o u r subtasks d e s c r i b e p o s s i b l e areas uf investigation.

7.7.4.1

.:.&

Subtask 6.4.1.1

E f f e c t s sf salt s p i l l s - s h o r t

term

S p i l l s of primary a n d / o r secondary s a l t imto the primary c s n t a i m e n t represemt one class of p o s s i b l e consequences of MSR a ~ c i d e n t s . S i n c e the i n s i d e of t h e containment boundary may b e covered by thermal i m u lation and, presumably, an i n n e r l i n e r , t h e p o s s i b l e e f f e c t s of such s p i l l s on the containment i n t e g r i t y and heat-remval c a p a b i l i t y should b e examined. Only s h o r t - t e r m exposures need t o b e c o n s i d e r e d , however, because a l l s a l t s p i l l s f l o w t o t h e f u e l d r a i n tank.

5.5.4.2

Subtask 6 . 4 . 1 . 2

Long-term e f f e c t s of s a l t - s p i l l r e s i d u e s

Najor s a l t spills, if they occur, are almost c e r t a i n t o leave s o m e s a l t r e s i d u e s i n the primary containment. The d e g r e e to which such r e s i d u e s are removed i s probably d e t e r d n e d by requirements f o r opening the corntatiment t o perform maintenance. However, i f r e s i d u e s are a c c e p t a b l e from a l l o t h e r s t a n d p o i n t s , i s shouPd be shown t h a t they will have no long tern deleterious e f f e c t on t h e containment s a f e t y c h a r a c t e r i s t i c s This subtask p r o v i d e s f o r t h e i n v e s t i g a t i o n of any such p o t e n t i a l l y harmful e f f e c t s * e

.:,,

This arrangement would be rather similar ts that on t h e i n s f d e of a PCRV ~ S Kan HTGR.

7-44

7.7.4.3

Subtask 6.4.1.3

Effects of o t h e r i m p u r i t i e s

I n a d d i t i o n t o salt, t h e primary e o n t a i n m n t of an MSR could conceivably b e exposed t o the^ i m p u r i t i e s as a consequence o f an a c c i d e n t . b o n g the materials t o b e considered are a i r , drain-tank cooling f l u i d , and water from t h e containment c o o l i n g system. The c r e d i b i l i t y of such inS introt r o d u c t i o n s must b e c o n s i d e r e d , but t h e p o t e n t i a l C O I X W X ~ ~ R C ~ of ducing the contaminants h e l p s t o determine t h e importance o f exeluding s p e c i f i c m t @ + i a h . ?%US, 8QBe Study Qf the s a f e t y e f f e c t s of other COntEiDlhlaIIts i s proposed.

Task 6 4 2

7.7 * 5

S e i s m i c technology

Seismic e v e n t s , at l e a s t up t o t h e magnftude that m y be used as a s a f e shutdown earthquake (SSE), s h o u l d be examined i n M S W s a f e t y s t u d i e s , p a r t l y to d@teHnine t h e responses O f C0IIlpOnetrts m d Sy§t@ms to Such events and p a r t l y to help d e f i n e t h e s a f e t y requirements ~f p l a n t d e s i g n s to survfve the SSE w i t h o u t u n a c c e p t a b l e consequences. Although methods and e v a l u a t i n g s e i s m i c e v e n t s are r e a s o n a b l y w e l l e s t a b lished, additional work may be r e q u t r e d to peranit a n a l y s i s of the Calff e r e n t c o ~ ~ p ~ n e an tds systems a s s o c i a t e d w i t h PER'S. This t a s k p r o v i d e s f o r m y s p e c i a l development of s e i s m i c a n a l y s i s c a p a b i l i t y t h a t i s needed.

9.7.5.1

Subtask 6 . 4 . 2 . 1

F a i l u r e of primary-system components

The a b i l i t y of e x i s t i n g t e c h n i q u e s t o a n a l y z e response and d e s c r i b e f a i l u r e modes sf MSW cornp~nentsunder s e i s m i c s t ~ e w s i~l l b e examined under this subtask. Any r e q u i r e d c a p a b i l i t i e s that are p e c u l i a r t o MSB's ~ u i be d deveiopea EBXI verified ~ O PUS^ ~n .XMPJLS~S.

7.7.5.2

Subtask 6.4.2.2

Failure of engineered s a f e t y f e a t u r e s

The same t y p e s of s t u d i e s i d e n t i f i e d in Subtask 6.4.2.1 would a l s o b e a p p l i e d to the engineered safety f e a t u r e s developed o r s p e c i f i e d f o r molten-salt r e a c t o r s . '&lese e f f o r t s are a s s i g n e d t o a s e p a r a t e s u b t a s k because of t h e i r importance t o t h e o v e r a l l s a f e t y of t h e plant.

7.7.6

Other s a f e t y technology tasks

Although no o t h e r needs f o r s a f e t y technalogy a s s o c i a t e d w i t h eomponemts and s y s t e m are c u r r e n t l y i d e n t i f i e d , i t is .-,onsidered l i k e l y that such needs will a r i s e as t h e g e n e r a l t e c h w ~ l o g yof % R P s evolves. m e r e f o r e , i t i s a n t i c i p a t e d that other t a s k s may, in the f u t u r e , b e added to t h i s group I

7-45 7.8

TASK GROUP 6.5

7.8.1

Objective

SAFETY INSTRUMENTATION AND COMmOES

P r e l i m h a r y s t u d i e s sf the needs f o r s a f e t y i n s t m e n t a t i o n and controls %OH MSR's have r e v e a l e d no majar unusual requirements. Sme c o n s i d e r a t i o n m u s t b e g i v e n t o t h e f a c t that t h e d e v i c e s w i l l be r e p i r e d to pemfom a t h i g h ambient t e m p e r a t u r e s , b u t this i s a n ~ m a ol p e r a t i o n a l as well, as a s a f e t y requirement. Nevertheless, i t seems p r u d e n t t o examine carefully the s a f e t y i n s t r u m e n t a t i o n and c o n t r o l s weeds as reactor designs are developed and g e n e r a l s a f e t y needs are d e f i n e d t o e n s u r e t h a t any unique s a f e t y requirements are recognized and r e s o l v e d .

7.8.2

Schedule and funding

The review of s a f e t y i ~ t ~ t r 1 1 1 1 1 a t a t Fand ~ 1 ~c ~ n t r o needs l~ should b e based on a r e a s o n a b l y w e l l establi3ked c o n c e p t u a l p l a n t d e s i g n . T h e ~ e f o ~no e~ effort i s p r o j e c t e d f o r the f i r s t se-rreral y e a r s of t h e p r o g ~ m . However, i t i s presumed that i n s t r u m e n t a t i o n and c o n t r o l s work i n t h i s task group will b e c a r r i e d o u t d u r i n g t h e p e r i o d PY 1981 through IT 1985, and opera t i n g funds i n the m o u n t of $50,880 w i l l be r e q u i r e d i n each of t h e s e years. It i s a l s o p o s s i b l e that W W ~ would be r e q u i r e d a f t e r this p e r i o d . Development t o meet normal o p e r a t i o n a l needs w i l l proceed (see Seetion 12) and i f t h a t work w e r e t o suggest a need f o r e a ~ H i e ~s afety S i n c e n~ s p e c i a l s a f e t y s t u d i e s , they would b e i n s t i t u t e d as required. needs are a n t i c i p a t e d , t h e funding p r o j e c t e d f o r t h i s t a s k group p r o v i d e s o n l y ~ Q Ps u r v e i l l a n c e of r e l a t e d a c t i v i t i e s and i d e n t i f i c a t i o n of p o s s i b l e weeds. I f a c t u a l s a f e t y needs w e r e i d e n t i f i e d , a d d i t i o n a l funding would be r e q u i r e d t o s u p p o r t t h e a s s o c i a t e d development e f f o r t .

7.8.3

Facilities

N o f a c i l i t y needs beyond those r e q u i r e d for instrumentation and controls development w i t h i n the base progrm are a n t i c i p a t e d .

7.8.4

Task 6.5.1 I d e n t i f i c a t i o n of instrumentation and c o n t r o l s s a f e t y needs

This t a s k p r o v i d e s for a review sf s a f e t y i n s t r u m e n t a t i o n and contro1 requirements f o r MSR's under a c c i d e n t c o n d i t i o n s and t h e i d e n t i f i c a t i o n sf any n e e d s which have not been and are n o t L i k e l y t o be m e t w i t h i n t h e b a s e p r o g r a m development e f f o r t . Also provided f o r is a review of t h e ~ ~ ~ i stechnology t i ~ g f o r o t h e r ~ p e a c t oc~o n c e p t s t o determine which needs, i f any, can be met by p r o d u c t s sf other deV@lQpmeRtprograms.

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7-46 7.8.5

Technology development t a s k s

Tasks t o develop i n s t r u m e n t a t i o n and c o n t r o l s s a f e t y t e c h o l o g ) ~w i l l b e added t o t h i s program plan when, m d i f , needs f o r such d w e l o p e n t are i d e n t i f f e d and j u s t i f i e d . The nature of t h o s e tasks is dependent on the results of Task 6.5.1.

7 9 1 e

Ob-j ectives

Tbe primary e f f o r t to develop the maintenance t e c h o l o g y f o r MSR's i s des c r i b e d h S e c t i o n 11. Stnce the technology t h a t is developed f o r normal maintenance must be a b l e t o cope w i t h high levels of radfoaetivtty througho u t t h e r e a c t o r primary system, i t i s b e l i e v e d t h a t s m e a s p e c t s of t h i s technology can be adopted o r adapted t o help m i t i g a t e a c c i d e n t consequences ancl t o r e c o v e r frm accidents. ng t h e s i t u a t i o n s i n which maintenance procedures could b e n e f i t K ~ ~ C % O I s- a f e t y are t h o s e where t h e secondary conta5nment remains a c c e s s i b l e and work must be done t o r e s t o r e vital services, such as a f t e r h e a t removal capability. The o b j e c t i v e of t h e work Ln t h i s task g~-otapi s t o i d e n t i f y ways i n which maintenance t e c h n ~ l o g ycould cont r i b u t e to reactor s a f e t y and t o develop systems and procedures that are sham t o b e u s e f u l .

7.9.2

Schedule and funding

A p p l i c a t i o n of MSW maintenance technology t o s a f e t y s i t u a t i o n s w i l l req u i r e s u b s t a n t i a l l y g r e a t e r development of t h e methods ancl tools t h a n is now a v a i l a b l e . I n addition, d e t a i l e d s t u d i e s are r e q u i r e d of situations i n which maintenance a c t i v i t i e s might be used t o enhance s a f e t y . Conseq u e n t l y , t h i s work i s c o n s i d e r e d t o be a r e l a t i v e l y long-range e f f o r t which would proceed roughly i n p a r a l l e l w i t h t h e d e s i g n and c o n s t r u c t i o n sf r e a c t o r f a c i l i t i e s . No work i s p r o j e c t e d b e f o r e 1982, and subsequent work i s c a n t i n g e n t on the s u c c e s s of t h e i n i t i a l e f f o r t . The funding f o r t h i s work would begin a t a l o w level and g r a d u a l l y increase to levels i n d i c a t e d by t h e w e s t a b l i s h e d needs. It i s c u r r e n t l y planned t h a t work will be c a r r i e d o u t d u r i n g EY 1982 through 1985, and $50,000 in operating funds w i l l be r e q u i r e d i n each of t h e s e y e a r s . 7.9.3

Facilities

... vii' <&.A

7-47

7.9.4

_Task 6.6.1

De~elopment of maintenance technology to enhance s a f e t y

This task, and ~ t h e rLn~ this t a s k group which may s u b s e q u e n t l y be d e f l n e d , will develop s p e c i a l maintenance t e c h f q u e s , p r o c e d u r e s , and equbpment, consistent with the normal maintenance technology, t o help m i t i g a t e t h e consequences of major p o s t u l a t e d accidents ana to assist i n the recovery %rsw mch a c c l d e ~ t s . specific t e c ~ u l o ~ o gtyo be developed is contingent ~n the d e f i n i t i o n and j u s c i f g c a t i o n of s a f e t y needs. TASK GROUP 6.7 LING

9.10

SAFETY TECHNOLOGY OF PROCESSING

WASTE STBUGE

m 7* l o 1 0

Obj ective

S k e e a n MSR p l a n t iracorpsrates i t s OW fuel processing and i n t e r m e d i a t e tern mste s t o r a g e f a c U i t i e s , the s a f e t y t e c b s l o g y a s s o c i a t e d with these f a c i l i t i e s must b e addressed as p a ~ tof the weraB1 s a f e t y effort. ( S a f e t y s i g m i f i c & t events 2n these ancillary f a c i l i t i e s probably w i l l not d i r e c t l y af%ect reactor s a f e t y , and vice versa9 b u t s m e safetyr e l a t e d b t e r d e p e n d e w c e may b e i n v o l v e d . ) The purpose of the work i n t h i s task group i s t o clmelo~.any needed s a f e t y t e ~ k l ~ ~ lt o~ minimize gy t h e p o s s i b i l i t y of major a c c i d e n t s i n t h e s e f a c i l i t i e s and t o help w i t i g a t e the consequ.ences of a c c i d e n t s whPch wight Q C C U ~ .

7 10.2

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Schedule and funding

Postulated a c c i d e n t s i ~ ~ ~ l the ~ if u~e l lg rgo c e s s i ~ gand waste f a c i l i t i e s w 5 l l be exm2ned as p a r t of the s a f e t y guidance e f f o r t , Task G K O U ~ 6.1. %sx~ltsof that e f f o r t , along with the o n s e t of d e s i g n and construction of facilities for a reactor w i l l determine t h e schedule for this W Q K ~ , However, no significamt effort is a n t i c i p a t e d p r i o r t o 1982. It i s planned t h a t work will b e carried o u t during 1982 and 1983, and $ ~ O , O O Oin operating funds w i l l be r e q u i r e d auping each Qf these B e s c h e d u l e and funding beyond this p e r i o d depends on t h e n a t u r e of the safety n e e d s that are i d e n t i f i e d . The initial funding %or t h i s work i s a t a low level t o p e r m i t p l a n n i n g of t h e s a f e t y development work required t s m e e t the needs. A d d i t i o n a l funding would be provided as needed t o carry out s p e c i f i c developments.

7.10.3

Facilities

MQ f a c i l i t y needs can ~ ~ r r e n t be l y p r o j e c t e d f o r t h i s work. ... .....

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7-48

rnFErnNCES FOR SECTION 7

Title 10, Code of Federal R e g u l a t i o n s , Part 100, Paragraph POO.11.

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REACTOR DESIGN AND ANALYSIS

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The o b j e c t i v e s of t h i s a c t i v i t y are: (I) t o develop t h e conceptual r c i a l MSBR i n s u f f i c i e n t d e t a i l t o i d e n t i f y d e s i g n f o r a c o ~ ~ ~ ~ ~IQBFB-MW(e) t h e major areas im which a d d i t i o n a l technology development i s r e q u i r e d and t o produce meaningful estimates of t h e n u c l e a r and economic p e r f o r mances of t h i s r e a c t o r t y p e , (2) t o develop t h e d e s i g n c r i t e r i a and c o n c e p t u a l d e s i g n for a m o l t e n - s a l t demonstration r e a c t o r t h a t w i l l prov i d e t h e i n f o r m a t i o n n e c e s s a r y f o r c o n s t r u c t i o n of commercial MSB%ZPs i n s u f f i c i e n t d e t a i l t o i d e n t i f y a d d i t i o n a l technology development which i s r e q u i r e d f o r c o n s t r u c t i o n of t h e demonstration r e a c t o r and t o p r o v i d e improved estimates of t h e c a p i t a l and o p e r a t i n g c o s t s f o r t h e demonstrat i o n r e a c t o r , ( 3 ) t o develop t h e d e s i g n c r i t e r i a and conceptual design f o r a ~ ~ ~ ~ l t e n - tseaslt t r e a c t o r i n s u f f i c i e n t d e t a i l t u i d e n t i f y a d d i t i o n a l technology development which i s r e q u i r e d f o r c o n s t r u c t i o n of t h e t e s t r e a c t o r and t o p r o v i d e improved estimates of t h e c a p i t a l and o p e r a t i n g c o s t a f o r t h e test r e a c t o r , and ( 4 ) to develop t h e d e s i g n c r i t e r i a and c o n c e p t u a l d e s i g n f o r a m o l t e n - s a l t t e a t r e a c t o r mockup i n s u f f i c i e n t d e t a i l t o i d e n t i f y a d d i t i o n a l technology development which i s r e q u i r e d f o r c o n s t r u c t i o n of t h e test r e a c t o r mockup and t o p r o v i d e improved estimates of t h e c a p i t a l and o p e r a t i n g c o s t s f o r t h e mckup.

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An a d d i t i o n a l important o b j e c t i v e of t h i s a c t i v i t y i s t h e examination

of a l t e r n a t e r e a c t o r t y p e s such as m o l t e n - s a l t c o n v e r t e r reactors u s i n g uranium o r plutonium f u e l makeup as w e l l as uses f o r m o l t e n - s a l t r e a c t o r s o t h e r than l a r g e c e n t r a l s t a t i o n e l e c t r i c power g e n e r a t i o n i n s u f f i c i e n t d e t a i l t o assess t h e l i k e l y economic importance of a l t e r n a t e m o l t e n - s a l t r e a c t o r t y p e s . Limited conceptual d e s i g n work would b e c a r r i e d o u t on a l t e r n a t e r e a c t o r types which show promise.

8.1.2

Scope

The scope of t h i s a c t i v i t y c o n s i s t s of t h e g e n e r a l areas of (1) d e s i g n s t u d i e s f o r MSR power p l a n t s , (2) s y s t e m a t i c accumulation of d e s i g n i n f o r m a t i o n , ( 3 ) i d e n t i f i c a t i o n and development of codes and s t a n d a r d s , ( 4 ) examination of f a c t o r s i m p o r t a n t i n l i c e n s i n g MSR's, and ( 5 ) development of computational methods f o r n u c l e a r a n a l y s i s of MSR s y s t e m and t h e i r application.

8.1.2.1

Task Group 7 . 1

Design s t u d i e s of NSR power p l a n t s

The scope of t h i s t a s k group i n c l u d e s completing c o n c e p t u a l designs f o r ...

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a commercial lOOB-PIW(e) MSBR as w e l l as f o r a demonstration r e a c t o r , a t e s t r e a c t o r , a d a t e s t r e a c t o r mockup i n s u f f i c i e n t d e t a i l t o i d e n t i f y and g u i d e t h e r e q u i r e d technology delreaboprnent and t o provide meaningful

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8- 2 me i n t e n t of t h e d e s i g n work i s f o r program guidance o n l y , znd no systems will b e designed i n s u f f i c i e n t detail %OX component f a b r i c a t i o n . Limited s t u d i e s and c o n c e p t u a l des i g n w%%%b e c a r r i e d o u t f o r FER t y p e s other than h i k p e r f o m n c e b r e e d e r s i n o r d e r t o assess t h e i r l i k e l y economic impact. c o s t and schedule p r s j e e t i o n s .

8.1.2.2

8.1.2.3 0% t h i s task group includes t h e identfffeation and development of t h e n e c e s s a r y codes and s t a n d a r d s f o r d e s i g n and construction of -Pisa p l a n t s and component development facilities. E x i s t i n g codes and s t a n d a r d s such as ASME Boiler and P r e s s u r e Vessel. Csde S e c t i o n 3 , Class 1, as well as w%)T s t a n d a r d s and q u a l i t y a s s u r a n c e p r o c e d u r e s , will b e c a r e f u l l y exmined with r e s p e c t t o PZSR systems, and additional codes and s t a n d a r d s w i l l be developed as necessary to ensure t h a t s a t i s f a c t o r y d e s i g n , COWstruction, i n s t a l l a t i o n , a ~ testing d procedures a r e availabbe.

The scope

Code cases r e q u i r e d f o r use of materials i n n u c l e a r s e r v i c e , such as t h e use of modified H a s t e l l ~ yN i n t h e MSBR primary c i r c u i t , w i l l b e developed and s u b m i t t e d as n e c e s s a r y .

8.1.2.4

Task Group 7 . 4

L i c e n s i n g of M S W F s

The s s s p e of t h i s t a s k group i n c l u d e s t h o s e a c t i v i t i e s r e q u i r e d t o ident i f y any c h a r a c t e r i s t i c sf molten-sa%%r e a c t o r s which could a d v e r s e l y a f f e c t o b t a i n i n g a l i c e n s e for ~ g e r a t i ~and n to develop a c c e p t a b l e alternatives to & . t i g a t e s e r i o u s aeiay. sn i t is intended t h a t s u f f i c i e n t a t t e n t i o n b e gfven t o t h i s area t h a t q u e s t i o n s a f f e c t i n g Pic'ewsing can b e i d e n t i f i e d e a r l y and s u i t a b l e a l t e r n a t i v e s developed b e f o r e s i g n i f i c a n t investments ape made i n techno1ogy deveP0psraent and conceptual d e s i g n ,

8.1.2.5

Task Group 7 . 5

Nuc

me scope of t h i s t a s k group i n c l u d e s t h e n u c l e a r a n a l y s i s of control

system and methods, and t h e develapment of a d d i t t o n a l computer methods as requLred for a n a l y z i n g the nuclear performance of MSR system under b o t h s t e a d y - s t a t e and a n t i c i p a t e d t r a n s i e n t c o n d i t i o n s .

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8.2.1

P R O G M BUDGET AM%a SCHEDULE

Schedule

The d e s i g n s t u d i e s will concern several different r e a c t o r s and t h e r e will be over l a p p i n g i n t i m e , as c e r t a i n work on d i f f e r e n t concepts w i l l be carried on s i m u l t a n e o u s l y , The studies havLng to do with the IQOO-Pa3(e> MSBR, as an example, will be a c o n t i n u i n g study, The reference design r e p o r t e d i n QRbJL-4541 will be used as a point of d e p ~ t b t ~f eo these ~ s t u d i e s . Nuclear caleulatisns and c o s t a n a l y s e s w i l l b e updated as t h e s u p p o r t i n g technology deVeloplllent p%ogreSseS. F i g u r e 8.2.1 ShoWS dhgrpi%lPm a t i e a l l y how the major reactor d e s i g n e f f o r t s are i n t e r r e l a t e d and t h e involvement of i n d u s t r i a l p a r t i c i p a n t s i n t h e work. Also shorn, t o add perspeCtiVe, is p a r t 0 % t h e K @ a c t O % teChnOlOgy d @ V e l O p l D e f a t e f f o r t ( d i s cussed in detail in S e c t i o n IO) l e a d i n g t o t h e construetion and operation of a Components T e s t Facility- (CTF) which will p r o v i d e important i n p u t to the reactOK d e s i g n Work. The s t u d i e s O n CORCeptual d e s i g n s Sf C 6 ercial plants will g u i d e development Work and will i n d i c a t e areas i n which f u r t h e r work is r e q u i r e d . Initial work on the lQBB-m(e)plant w i l l d e a l p ~ i m a r . f l ywith s a f e t y . During 1995, s a f e t y s t u d i e s (see S e c t i o n 7) will occupy most of t h e d e s i g n a n a l y s i s work. Beginning in FY 1976, performance and economic a n a l y s e s w i l l be s t a r t e d a t 8 l o w l e v e l - Beginning in FY 1979, some c o n c e p t u a l d e s i g n WOK^ will b e started on t h e lOOQ-%(tF9(e) breeder. This e f f o r t will be d i r e c t e d toward several f e a t u r e s of t h e r e f e r e n c e d e s i g n t h a t are h o r n to require additional s t u d y .

The schedule c h a r t , T a b l e 8.2.1, shows t h r e e large p r o j e c t s leading to t h e commercia1 b r e e d e r : a molten-salt t e s t ~ e a c t o r(MSTR), an MS'GR mockup, and a demonstration r - c t e ~ . These will be s t a r t e d i n a staggered way shorn. ~ f t e ra s e r i o u s review has been made of %lagMSBW studies t h a t have taken place i n the p a s t , a s t a r t w i l l be made on d e t e r m i n i n g the p r e l i m i n a r y design ~f t h e d a o n s t r a t i o n plant. Factors related t o the %800-MW(e) MSBR which r e q u i r e further study inc l u d e heat exchanger design, core design, mog~erator graphite rmoVai, and t h e drain t a n k cooling system. It i s a n t i c i p a t e d t h a t by the beginning of FY 1977, any r e m i n i n g q u e s t i o n s r e g a r d i n g the c h o i c e of a secondary c o o l a n t will have been resolved. This is 8 r a t h e r u r g e n t q u e s t i o n that must be answered as soon as p o s s i b l e as it influences much s f the d e s i g n of t h e p l a n t . A l l a s p e c t s of s a f e t y i n ~ l ~ d i i n g 16975. l i c & n s & i l i t y Will be StUdbed thOPQUghlY be&lPlfng duKing

P r e l i m i n a r y c o n c e p t u a l d e s i g n of t h e d e m o n s t r a t i o n plant w i l l b e g i n i n e a r l y PY 1978, Basic questions such as the nu&er of p r h a r y f o o p s , t y p e of heat exchange^. and maintenance phi%osophy (removal. sf heat exc h a n g e ~versus ~ tube plugging) w i l l be c o n s i d e ~ e d . The wmber of primary ~ Q Q ~will S tend to determine the size of the components t o be tested i n t h e reactor mockup. Conceptual d e s i g n a f the demo p l a n t w i l l c o n t i n u e t h r o u g h s u t the p e r i o d covered by this activity as d e s i r a b l e chan design become a p p a r e n t from the technology development s t u d i e s .

8-4

Table

8.2.1.

Schedule

for

work on reactor

design Fiscal.

7.1

Design

studies

power

plants

7 e2

Design

technology

7.3

Codes and standards

7.4

Licensing

7.5

Nuclear analysis power plants

MssR

of MSRss of MSR

and analysis

year

8-6

A t e s t reactor, i n t e n d e d t o prove t h e features of the demonstration reactor, will be QpeKated prior to eorsagletion Sf t h e demonStKation 5f the t e s t reactor will begin in p l a n t design. Conceptual d e s FY 1978. T h i s timing all y e a r s of conceptual d e s i g n t o have been esnpheted on the lar planks in order to establish the basic elements of the test reactor.

Also by ET 1998, enough of the design technology will have been completed that high temperature d e s i g n bases will have been determined so that the conceptual design will be on reasonably firm ground. After two y e a m , by t h e end of E T 1979, the preliminary s a f e t y and hazard analyses will have been completed s o that authorization f o r the test reactor can be he p e r i o d FY 1981 through FY 1984, w i l l be ~ e q u i r e dto requested. complete enough of the detailed d e s i g n of the test reactor plant so that c ~ ~ n s t r u c t ican ~ n begin in early FY 1985. when d e s i g n sf t h e test reactOK p l a n t has been % a r g d J ?CoElpleted, Work can be concentrated on the design s f the chemical p r o c e s s i n g plant which i s scheduled f o r completion by m i d Fy 1986. The entire t e s t reactor plant should be completed by the beginning sf PY 1989, and o p e r a t i o n s f the system can b e g i n ,

effort w i l l be concerned with a reactor mockup. The f o u r t h major d e e i I n order to have the put from t h e other conceptual design studies, design of the mockup w i l l n o t be i n until the s t a r t 0% m 1979. All major decisions a b o u t design temperatures, salt compssitisns and component Configurations will have been reached by t h i s time. A l s o , code cases w i l l . be in preparation so that the necessary technology t o do the d e s i g n will be i n hand. thorization f o r the reactor mockup is to be the beginni O f FY 1981 with completion of a major portion requested S.E t h e detailed design by ET 1982.

MSTR and t h e demonstration reactor W O U ~b e~ developed a j o i n t OFWEi n d u s t r y e f f o r t . I n a d d i t i o n , i n d u s t r i a l reviews and evaluations will be extremely v a l u a b l e i n g u i d i n g t h e o v e r a l l technology develspment effort 0

Mainly f o r comparison p u ~ p o s e s , there are some o t h e r s t u d i e s which will p a r a l l e l t h e c o n t i n u i n g lOOO-W(e) studies. These w i l l i n v o l v e c h i e f l y a nm a l iy s~e s of C O ~ V ~ K ~ rCeXa c t o r s and plutonium-fueled n u c l e a r and e c ~ ~ ~ o MSIE%'s. Some c o n c e p t u a l designs will likely be made t o see where c a p i t a l C Q S ~ Scan be reduced by t h e more s i m p l e p l a n t s . These s t u d i e s w i l l be worked i n as they are needed.

A s u m a r y of t h e funding p r o j e c t e d f o r this activity area i s S ~ O W I i n Table 8.2.2, w i t h s g p a r a t i ~ ns f t h e O W and OBAYL-s~bcontr~istedi n d u s t r i a l components. The i n d u s t r i a l e f f o r t c o v e r s (1) early p a r t i c i p a t i o n by i n d u s t r y i n h e l p i n g t o define t h e c o n c e p t u a l d e s i g n of the lQOQ-N(e) MSBR, and a t e s t and demonstration r e a c t o ~and (2) i n d u s t r i a l a s s i s t a n c e on the d e s i g n and c o n s t r u c t i o n of l a r g e component test and development f a c i l i t i e s . The l o w level sf s u l p p ~ r tf o r %he 8RNL e f f ~ l p td u r i n g the f i r s t two y e a r s r e f l e c t s t h e fact t h a t no conceptual d e s i g n work is proj e s t e d ; only performance and safety assessment of t h e I - ~ ~ ~ K ~ I Xd eXs i g n i s planned. The 8 M L design effort would i n c r e a s e w i t h t h e o n s e t of c o n c e p t u a l d e s i g n work Pw PY 1977 and reach a peak d u r i n g FY 1 9 7 9 as the c o n c e p t u a l d e s i g n s of the MSTR and t h e MSTR mockup a r e completed. The ~ g e q ~ i r efunding d would then decltna somewhat; however, s i g n i f i c a n t s u p p o r t would be r e q u i r e d for more detailed c o n c e p t u a l d e s i g n s t u d i e s of t h e demonstration plant, and e s p e c i a l l y f o r c o n t i n u i n g work 0x1 MSR l i c e n s i n g and the development of codes and s t a n d a r d s .

8.2.3

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Key program m i l e s t o n e s

The completion of certalirn parts of t h e design and analyeis e f f o r t of mB'S Will repfesW.lt d I @ s t O n e s Of the pKogr2lRl. The f i r s t Of thest@, expected t o come i n about two y e a r s (E l 9 7 7 ) , is a firming up of the design technology t o the p o i n t where materials and design bases f o r t h e i r use at high tmperatures can be c o n s i d e r e d t o b e e s t a b l i s h e d . This should pernit t h e second Il=dlestome, a comlbtment in e a r l y m 6981 to build it test reactor.

7.1

Design plants

studies

7.2

Design

technology

7.3

Codes and standards

7.4

Licem3ing

%gures

1975

1.976

1977

1978

1979

1980

1981

1982

1983

1984

1985

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170 (300)

177

203

393

400

415

395

275

225

157

230

172

141

128

192

200

130

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200

128

192

250

200

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1986

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8-9

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BACKGROUND AND STATUS

A comprehensive sununary of t h e background and s t a t u s of t h e m o l t e n - s a l t r e a c t o r w a s i s s u e d i n August l 9 7 2 ; I and s i n c e t h e program w a s i n t e r r u p t e d soon a f t e r t h e r e p o r t w a s i s s u e d , t h e i n f o m a t i o n c o n t a i n e d i n i t i s s t i l l reasonably c u r r e n t .

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Over t h e p a s t twenty y e a r s , s e v e r a l m o l t e n - s a l t r e a c t o r p l a n t s have been examined c o n c e p t u a l l y , and two e x p e r i m e n t a l molten-salt r e a c t o r s were built and o p e r a t e d a t OWL. The A i r c r a f t Reactor Experiment w a s o p e r a t e d b r i e f l y i n 1954 ( r e f . 2) and demonstrated t h e b a s i c concept. However, s i n c e t h e mission of t h a t p r o j e c t w a s n o t c e n t r a l - s t a t i o n power generat i o n , t h e r e a c t o r lacked many f e a t u r e s t h a t are important for l a r g e scale b r e e d e r s . f n t h e middle 1960's a n o t h e r m o l t e n - s a l t r e a c t o r , t h e MSBE, w a s o p e r a t e d f o r an extended p e r i o d of t i m e and y i e l d e d much valua b l e d a t a upon which power r e a c t o r concepts could b e based. 'This system w e d a f u e l salt g e n e r a l l y s i m i l a r t o t h a t proposed f o r t h e b r e e d e r , an unclad-graphite moderator, a secondary c o o l a n t s a l t c i r c u i t , and a s t r u c t u r a l a l l o y of i n t e r e s t t o t h e b r e e d e r concept.

Two b a s i c b r e e d e r concepts have been s t u d i e d and r e p o r t s have been i s s u e d on t h e conceptual d e s i g n s t u d i e s . y 4 The f i r s t of t h e s e involved t w o r a d i o a c t i v e primary (1001ant~, a f i s s i l e stream of uranium, l i t h i u m , and b e r y l l i u m f l u o r i d e s and a completely s e p a r a t e b l a n k e t o r f e r t i l e s a l t of t h o r i m , l i t h i u m , and b e r y l l i u m f l u o r i d e s . This system appeared t o o f f e r e x c e l l e n t b r e e d i n g performance and a r e l a t i v e l y simple f u e l proce s s i n g p l a n t , b u t m a i n t a i n i n g t h e s e p a r a t i o n of t h e two f l u i d s v i a g r a p h i t e t u b e s i n t h e c o r e would have been d i f f i c u l t i n v i e w of t h e dimensional changes which o c c u r i n g r a p h i t e d u r i n g n e u t r o n i r r a d i a t i o n . Developments i n t h e area of chemical p r o c e s s i n g and r e c o g n i t i o n of altern a t e n e u t r o n i c design p o s s i b i l i t i e s l e d to t h e adoption of a s i n g l e - f l u i d concept i n which b o t h t h e f i s s i l e and f e r t i l e materials are d i s s o l v e d i n one primary s a l t .

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d i r e c t e d toward t h e s i n g l e - f l u i d b r e e d e r system which f e a t u r e s a s i n g l e , l a r g e r e a c t o r vessel and f o u r primary c o o l a n t pumps t h a t c i r c u l a t e f u e l s a l t between i n t e r m e d i a t e h e a t exchangers and t h e c o r e . The r e a c t o r vessel c o n t a i n s unclad g r a p h i t e t o p r o v i d e n e u t r o n moderation and t h r e e 18 zones:'! c o r e , b l a n k e t , and r e f l e c t o r . F u e l s a l t c d r c u l a t e s through a l l t h r e e zones which are n o t p h y s i c a l l y i s o l a t e d from each o t h e r ; t h e d i f f e r e n t n e u t r o n i c e f f e c t s i n t h e zones are achieved Bay c a r e f u l l y s e l e c t i n g t h e fuel-to-moderator r a t i o f o r each zone. Each primary l o o p c o n t a i n s equipment f o r gas (helium) i n j e c t i o n and removal t o p r o v i d e f o r s t r i p p i n g of 1 3 5 ~ eand o t h e r v o l a t i l e s p e c i e s . Some f u e l s a l t i s c o n t i n u a l l y c i r c u l a t e d between t h e d r a i n t a n k and t h e primary loops to c o o l p o r t i o n s of major components and t h e off-gas stream. The d r a i n t a n k p r o v i d e s t h e i n i t i a l holdup f o r decay of f i s s i o n - p r o d u c t g a s e s as' w e l l as a f t e r h e a t removal c a p a b i l i t y i f the fuel s a l t must b e d r a i n e d from t h e primary l o o p .

8-10 eysnd t h e primary system, t h e r e are no major d i f f e r e n c e s between t h e one-fluid and the o l d e r , two-fluid concepts. A secondary salt, c u r r e n t l y sodium f l u s r o b o r a t e , t r a n s p o r t s t h e f i s s i o n energy from each i n t e r m e d i a t e h e a t exchanger t o a steam g e n e r a t o r which i s coupled t o a more-or-less conventional s u p e r c r i t i c a l s t e m system f o r g e n e r a t i o n of e l e c t r i c i t y .

arts of t h e prfwary s y s t m are c o n t a i n e d tn m e t a l - l i n e d , h e r m e t i c a l l y sealed c e l l s which p r o v i d e primary containment and radiation shielding. S e c o n d a q c ~ n t a i n ~ i~sn provided t by t h e u s u a l domed cylindrical s t r u c t u r e which eglchses t h e r e a c t o r p l a n t .

8.3.1

m:.

c.:.

Primary systems layout and structural d e s i g n

Although t h e basic r e a c t o r concept i s reasonably well e s t a b l i s h e d , t h e r e are m n y a s p e c t s t h a t have n o t y e t been s t u d i e d i n s u f f i c i e n t d e t a i l to r@SolVe dl potentia% qUestions. '%tae§e inCaUde the l a y o u t and d e s i g n Of all mjor p a r t s of t h e primary system. Since t h e primary c o o l a n t i~ an M B R c o n t a i n s t h e f i s s i l e material, b o t h t h e b r e e d i n g p e r f a m 8 n c e (dsub%Fng time) and t h e econoIlric p e ~ f o m a n c e are i n f l u e n c e d by t h e out-of-reactor i n v e n t o r y of f u e l s a l t (i-e., t h a t i . W the d r a i n fillPk, p U p B , p i p i n g , heat exchangers, and pKo@essingp l a n t ) . TGlus, t h e r e i s c o n s i d e r a b l e i n c e n t i v e t o make t h e primary s y s t e m as comp a c t as p o s s i b l e , c o n s i s t e n t w i t h t h e d e s i g n requirements of adequate h e a t t r a n s p o r t , long l i f e , m a i n t a i n a b i l i t y , and s a f e t y and r e l i a b i l i t y d u r i n g both s t e a d y - s t a t e and t r a ~ s i e n tc o n d i t i o n s . While a l l of t h e s e requirements were c o n s i d e r e d i n the e ~ o l ~ t i of o ~ tlh e c o n c e p t u a l d e s i g n and Payout (from which inventory, perfomance, and cost d a t a were develo p e d ) , t h e r e q u i r e d d e t a i l e d reviews and a n a l y s e s have not been performed to f d l y prove the designs." ~n p a r t i c u l a r , more stress a n a l y s i s work i s r e q u i r e d t o show that o r d i n a r y mechanical, as well as theasnab, s t ~ e s s e s throughout t h e s y s t m are compatible w i t h d e s i g n and life requirements f o r a l l conditions.

The p h y s i c a l arrangement sf the g r a p h i t e i n s i d e the r e a c t o r vessel of an NSBR i s important i n d e t e r m i n i n g the performaface sf the system. I n t h e "core" and "blanket" zones, t h e fuel (or g r a p h i t e ) volume f r a c t i o n a f f e c t s b r e e d i n g performances as well as t h e b a s i c n e u t r o n i c c h a r a c t e r , sf t h e p l a n t and m u s t , t h e r e f o r e , be carefully e s t a b l i s h e d and maintained d u r i n g all phases of o p e r a t i o n . The r e f l e c t o r must be cooled by flowing f u % l s a l t , but the fuel volume f r a c t i o n must remain l o w i n t h e o u t e r regions t o p r e v e n t h i g h f i s s i o n rates i n t h e s e r e g i o n s which would lead t o increased n e u t r o n l o s s e s ( l o w e r breeding gain) and g r e a t e r i r r a d i a t i o n damage t o t h e r e a c t o r v e s s e l . Since graphite dimensional changes are an

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effect o f neutron FPradiation, the core must be designed to aceornodate such changes w i t h o u t unacceptably degrading t h e r e a c t o r performance. The power densities and a t t e n d a n t f a s t - n e u t r o n fluxes i n t h e I n i g h - p ~ w e ~ regions w i l l limit t h e u s e f u l l i f e o f present-technology g r a p h i t e t o about f o u r full-power years. T h e r e f o r e , t h e graphite arrangement must also A l m f o r p e r i o d i c replacement of a t least some of t h e m d e r a t o r . A d d i t i o n a l work i s r e q u i r e d t o r e s o l v e remaining d e s i g n q u e s t i o n s rel a t e d t o the g r a p h i t e eonfigurat8on and the removal amd replacement of g r a p h i t e i n t h e c o r e region. A d d i t i o n a l work i s r e q u i r e d t o e n s u r e t h a t r a d i a t i o n h e a t i n g i s approp r i a t e l y handled i n the r e f e r e n c e d e s i g n . B u ~ i n gs p e r a t i o r t , s u f f i c i e n t s a l t o r o t h e r c o o l a n t f l o w must b e a v a i l a b l e t o remove d i r e c t r a d i a t i o n S; r e j e c t i o n from components must a l s o be h e a t from all C C X I I ~ Q I I ~ ~ ~heat adequate t o p r e v e n t o v e r h e a t i n g due t o t h e decay of d e p o s i t e d f i s s i o n p r o d u c t s when n~ s a l t i s p r e s e n t (as a f t e r a d r a i n ) ; t h e d r a i n tank c o o l i n g system must s a f e l y a c c o m o d a t e a l l n o m a 1 and c r e d i b l e abnormal h e a t removal s i t u a t i o n s . A l l of t h e s e c o n s i d e r a t i o n s have been faCtQI-ed i n t o t h e d e s i g n , b u t not w i t h s u f f i c i e n t refinement. Of t h e primaPgr-SyStem COI%IpQHlentSWithin t h e pkhargr CQn~ainlTlentmust b e physically s u p p ~ r t e di n such a way as t o a c c ~ ~ ~ ~ thermal ~ ~ ~ d expansion a t e effects and major d i s t u r b a n c e s , such as e a r t h q u a k e s , w i t h o u t l o s s of i n t e g r i t y . Although the i n t e r n a l c o n s t r u c t i o n of the c e l l s i s similar i n p r i n c i p l e to t h e i n t e ~ i oof~ t h e PCRV f o r an HTGR, t h e primary system p r e s s u r e boundary i n an MSBW i s independently contained by t h i s s t r u c t u r e r a t h e r than b e i n g a n e a r - i n t e g r a l p a r t of i t . Consequently, a d d i t i o n a l d e s i g n e f f o r t must b e a p p l i e d to equipment-support concepts.

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8.3.2

Design methods

Comercial-scale mBRPsw i l l be d e s i ed mechanically f o r a u s e f u l l i f e of 36 y e a r s a t temperatures as h i g h as 1300°F w i t h numerous thermal eyeles. However, the d e s i g n p r e s s u r e s are relatively l o w e These cond i t i o n s are g e n e r a l l y s i m i l a r t o those f o r HTGR's afld m B R P s , and c o n s i d e r a b l e effort $8 b e i n g expended in those p r c ~ g r a sto develop des i g n methods that will e n s u r e that components and s y s t e m f u n c t i o n safely andl r e l i a b l y uader such c o n d i t i ~ n s . Much of the technology that i s b e i n g developed w i l l b e a p p l i c a b l e , or a t least a d a p t a b l e , t o MSBR design problems. Howeverb t h e primary MSBR s t r u c t u r a l material (Hastelloy E9) has d i f f e r e n t p h y s i c a l and a g i n g c h a r a c t e r i s t i c s than the materials t s b e w e d in e i t h e r EHTGR's 0% W B W ' s . Therefore, considerable e f f o r t w i l l be r e q u i r e d t o a d a p t , demonstrate t h e a p p l i c a b i l i t y o f , and a p p l y a p p r o p r i a t e d e s i g n methods t o MSBR systems.

8-12

e x i s t s f o r t h e k i n e t i c a n a l y s i s o f c i r c u l a t i n g - f u e l r e a c t o r s , as evidenced by t h e s u c c e s s f u l d e s i g n of t h e MSFaE. Some a d d i t i o n a l methods development w i l l b e needed for t h e a c c u r a t e a n a l y s i s o f l a r g e r reactors such as t h e r e f e r e n c e MSBR, p a r t i c u l a r l y f o r t h e larger and more r a p i d t r a n s i e n t s that must be c o n s i d e r e d f o r o f f - n o m a 1 and a c c i d e n t condit i o n s . In a d d i t i o n , methods w i l l have t o b e developed to d e s c r i b e the transient behavfor of an i n t e g r a t e d MSBR p l a n t from t h e c o r e through t h e stem system. 8.3.3

Capital c o s t s

C a p i t a l cost studies on m o l t e n - s a l t r e a c t o r p l a n t s have been made i n r e c e n t y e a r s by s ~ v ~ Pindependent ~ P o r g a n i z a t i o n s . OWE e s t i m a t e d t h e c o s t s f o r the 100Q-E/BW(e) r e f e r e n c e d e s i g n . Independently, Black and Veatch, t h e W e a ~ t ~Assessment r P a n e l of t h e Edison E l e c t r i c I n s t i t u t e , and the Molten-Salt Group of a a s c o e s t i m a t e d the c a p i t a l c o s t s of MSBR s y s t e m . !.%e c o n c l u s i o n s from all t h e s e s t u d i e s were t h a t MSBRTs appear t o be economically a t t r a c t i v e in t h e U.S. p o ~ economy. e ~ However, each of these s t u d i e s was necessarily l b i d t e d in precision by the s t a t e of development 0% the c o n c e p t u a l design t h a t w a s s u b j e c t e d t o a n a l y s i s . Suck limitations w i l l c o n t i n u e t o e x i s t u n t i l MSBR's r e a c h commercial a p p l i c a t i o n , but t h e levels of u n c e r t a i n t i e s can b e expected t o diminish as t h e r e a c t o r d e s i g n evolves. T h e r e f o r e , the c a p i t a l c o s t s , and all other aspects of MSW ~ C B ~ O B ~ I Cs hS o, u l d %>efrequently reassessea to ensure t h a t d e s i g n and d e v e l ~ p r n e n te f f o r t s are b e i n g a p p l i e d t o system t h a t are, in f a c t , a t t r a c t i v e .

An important a s p e c t of the c a p i t a l (and o p e r a t i n g ) cost assessment of MSW's is d e t e m i n i n g t h e impact which v a r i o u s d e s i g n options have on CQst. %he refeHebaC.43 1 3 8 u s e s a p a r t i c u l a r design c ~ ~ f i g u r a t i ~an , p a r t i c u l a r secondary e s o l a n t , and a p a r t i c u l a r s t e m cycle. However, various alternatives have b e e n , and w i l l c o n t i n u e t o b e , advanced from t i n e t o t i m e . Among t h e p o s s i b l e a l t e r n a t i v e s t h a t have been s u g g e s t e d ik%e C o t l V e % t e K and S%mpEeb u r n e r %eactQrs,SlTd-Pel: Or TtlUlti-Usf? Pf&BCtoPB, a l t e r n a t e secondary c o o l a n t s , s y s t e m w i t h two ( d i f f e r e n t ) i n t e r m e d i a t e c o o l a n t c i r c u i t s i n series, and a l t e r n a t e stem c y c l e s . !!%e economic e f f e c t s of such a l t e r n a t i v e s , s i n g l y and in v a r i o u s combinations, s h o u l d be examined t o p r o v i d e a sound basis f o r choosing t h e most d e s i r a b l e s y s t e m ( s ) to b e developed.

8 4 1 e

0b.i ective

The ultimate o b j e c t i v e s f d e s i g n s t u d i e s of PER'S is t o b e a b l e t o d e s i g n a dependable, safe, nolten-salt b r e e d e r ~ e i ~ ~ that t o r w i l l produce excess fissile material from f e r t i l e t h o r i m a t a s u f f i c i e n t r a t e t o c o n t r L i b ~ t e SignifiC!antly to the W.S. e l e c t r i c power dt3MIlds. me 9ea@tO% EnuSt have a capital c o s t t h a t is c o m p e t i t i v e w i t h o t h e r types of e l e c t r i c a l genera t i n g p l a n t s of comparable s i z e and the o p e r a t i n g c o s t s must also be

...

8-13

competitive w i t h such p l a n t s . I n a t t a i n i n g t h i s o b j e c t i v e , i t i s o b v i o u s l y n e c e s s a r y t o develop t h e technology, i n c l u d i n g v i a b l e cornpanents t o be used i n suck a p l a n t . The c o n t r i b u t i n g chemical, mater i a l s , p r o c e s s i n g , t e ~ h n ~ l ~ g and g r , r e l a t e d p ~ ~ g r ~ iare m s discussed i n o t h e r s e c t i o n s of t h i s program p l a n . 8.4.2

Schedule

The d e s i g n s t u d i e s will be concerned w i t h a number of s e p a r a t e r e a c t o r s . (See a l s o Fig. 8 . 2 . 1 f o r a diagram showing t h e i n t e r r e l a t i o n of t h e s e a c t i v i t i e s ) . The i n i t i a l advanced c o n c e p t u a l s t u d i e s , i n conjunctisn w i t h accomplishments i n o t h e r technology areas, w ~ ~ be l dexpected t o p r ~ v i d ea b a s i s f o r and a p p r o v a l of c o n t i n u a t i o n of component technology development on a l a r g e r scale. Alter r e c e i p t s f such a p p r o v a l , t h e p r e l i m i n a r y c o n c e p t u a l d e s i g n for t h e demonstration reactor w s d d b e c a r r i e d o u t and t h e major f e a t u r e s of t h e m o l t e n - s a l t t e s t r e a c t o r (WTR) would be d e f i n e d . The next s t e p would b e t h e c o n c e p t u a l design of t h e NSTR mockup as a l e a d - i n t o i t s d e t a i l e d d e s i g n and construction. This f a c i l i t y , which would n o t be o p e r a t e d as a c r i t i c a l r e a c t o r , would pernit p a r t i a l and, i n some cases, complete t e s t i n g of f u l l - s c a l e MSTR components i n a r e a c t o r - l i k e environment. Simultaneous with o p e ~ a t i ~ n of t h e MSTR mockup, other a s p e c t s s f o p e r a t i o n and t e s t i n g s f developmental equipment would be c a r r i e d o u t i n t h e Components T e s t F a c i l i t y (see Section I O ) . A f t e r o p e r a t i o n of t h e MSTR, a d e ~ ~ ~ s t r a t ri eoa nc t o r p l a n t would b e c o n s t r u c t e d and o p e r a t e d . The s c h e d u l e f o r this t a s k group, Table 8 . 4 . 2 , i n d i c a t e s work done a t ORm and a l s o work a n t i c i p a t e d t o b e done by i n d u s t r i a l o r g a n i z a t i o n s . 8 4*3 e

Funding

The o p e r a t i n g fund requirements f o r design s t u d i e s are slizo~ni n T a b l e 8 . 4 . 3 . The i n i t i a l d e s i g n e f f o r t would b e g i n a t a How l e v e l in F?f 1 9 7 4 and i n crease slowly u n t i l e f f o r t s a s s o c i a t e d w i t h major f a c i l i t i e s are undertaken. However, s i n c e t h e c o n s t r u c t i o n d e s i g n e f f o r t s f o r t h o s e f a c i l i t i e s are i n c l u d e d i n o t h e r areas (see S e c t i o n s 1 3 , 1 4 , 1 5 ) the funding for work i n t h i s a c t i v i t y does n o t r e a c h a high level. A s work on t h e major f a c i l i t i e s becomes the primary e f f o r t , t h e r e q u i r e d s u p p o r t f o r t h i s a c t i v i t y d e c l i n e s , but some s u p p o r t must be maintained to p r o v i d e s ~ r v e i l l a n c e , m o n i t o r i n g , and t e c h n i c a l guidance sf o t h e r a c t i v i t i e s .

8.4.4

.... .....

,:..e

.... -9.

..: ._

i ....A

Task 7.1.1

BRNL s t d i e s of lQQQ-MM(e)MSBW

The e v o l u t i o n of m o l t e n - s a l t r e a c t o r s is expected t o proceed from an MSTR mockup, t o t h e MSTR, t u a d e m o n s t r a t i o n r e a c t o r , and f i n a l l y t o comereial p l a n t s . However, t h e i n c e n t i v e for f o l l o w i n g t h i s p a t h d e r i v e s from t h e attractiveness of t h e f i n a l o b j e c t i v e system - t h e 1080-W(e) b r e e d e r r e a c t o r . In a d d i t i o n , t h e i n t e r m e d i a t e r e a c t o ~ s y s t e m will all b e designed and operated t o f u r t h e r t h e development

Table 8.4.2.

Schedule fcm wcark in Task Graup 7.1 -Design

7.f.l

ORNL studies of 1000--W(e) HSBR 7.1.1.1 Overall conceptual design 7.1.1.2 Cure desQn 7.1.1.3 Prfnnary system layeut 7.1.1.4 System structure and support 7.1.1.5 Rejection of ~adiatlon heat 7.1.1.6 Design alternatives 7.1.1.7 Demonstration reactor

7.1.2

hdustrial. MSBR 7.1.2.1 7.1.2.2 7.1.2.3

studies

of 1000-W(e)

System daqbgn description and cost analysis Recommended research and development program Safety analyses

7.1.3

OF@&study af Molten-Salt Reactor

Test

7.1.4

Industrial $tudy of l"lolten-Salt Test Ractsr

7.1,s

Studies af alternate uses far MSR's

designs

and

studies

for MSR power plants

Fiscal

year

Table

8.4.3.

Operating

fund

requirements

for (cemts

Task in

Group

Boo90

7.1

-Design

studies

Fiscal

7.1.1

7.1.1.6 7.1.1.7

of lOOO-MM(e) MSBR Qverall conceptual design Core design Prinlary system Bayout Sptem structure and support Rejection of radiation heat Design alternatives Demonstration reactor

Subtotal

7.1.P

OWNI,

studias

7.B.B.P 7.1.1.2 7.1.1.3 7.1.1.4 7.1.1.5

7.1.2

Inglustrial mm. 7.1.2.1

studies

7.1.2.3 Subtotal.

7.1.2

OKNL study Reactor

of Pfolten-Salt

7.1.4

Industrial Salt Test

study of MoltenReactor

Total 7.1 a~~~hh3 b Figures

Studies

alternate

and uses

for

operating

funds

power

plants

140a

year

12 32 --__----76

128

150

200

150

125

128

150

200

2QQ

I.50

125

(lao)b (50) (50)

taoo>

7.1.3

7.1.5

lQQQ-W(e)

System design deserip tion and cost analysis Recommended research and devehpment program Safety analyses

7.1.2.2

dollars)

Test

designs

MS's fob

Task Grloup

~gineering in parentheses

amiya~s represent

in supple industrial

dety

stuaie.9

participation

177

203

393

4QQ

415

395

275

225

tdd~~

and are

totaled

devdopment. separately.

8-16 of t h e b r e e d e r t e c h n o h g y . Consequently, i t is important t o have as complete amd d e t a i l e d a c o n c e p t u a l d e s i g n as possible f o r the b r e e d e r t o p e d t a c c u r a t e assessment of i t s v a l u e t o the U.S. power e c o n o v and t o h e l p e s t a b l i s h t h e d e s i g n and perfomance requirements of t h e developmental p l a n t s . The. work i n this task i s dih-ected toward t h e p r ~ d ~ c t of i o an ~ advanced conceptual d e s i g n f o r a 1BOB-m(e) MSBR and a demonstration r e a e t o r e

8.4.4.1

Subtask 7.1.1.1

O v e ~ d conceptual l design

A r e f e r e n c e conceptual a e s i produced by o m , 4 b u t that design was based om particular requirements (e.g., f o r c o r e moderator d e s i g n and equipment function, s u p p o r t , and l a y o u t ) that are n o t n e c e s s a r i l y optimum. S p e c i f i c p o r t i o n s of t h e d e s i g n which s h o u l d b e reexam%ned, and p o s s i b l y r e v i s e d , are d i s c u s s e d i n o t h e r s u b t a s k s of t h i s g e n e r a l task. The i n i t i a l work i n Subtask 7 . 1 . 1 . 1 w i l l b e d i r e c t e d toward a review of t h e r e f e r e n c e system w i t h emphasis on t h e p r o c e s s d e s i g n . I n t e r e l a t i o n s between t h e s t e m c y c l e , t h e s e c o n d a q coolant, and the primary s a l t w i l l b e s t u d i e d f u r t h e r , and a comprehensive study of t r i t i m management will b e undertaken. Subsequently, as system d e s i g n modifications are developed, t h e y will be i n t e g r a t e d into a compatible o v e r a l l eoneeptual d e s i g n t h a t w i l l b e s u s c e p t i b l e t o d e t a i l e d performance and economic assessment.

8.4.4.2

Subtask 7.1.1.2

Core d e s i g n

The d e s i g n c r i t e r i a f o r an MSBR are determined by t h e neutronic p e r f o r manee r e q u i r e m e n t s , w i t h a p p r o p r i a t e c o n s i d e r a t i o n s of o p e r a t i o n a l e f f e c t s and maintenance needs. I n t h e c u r r e n t r e f e r e n c e concept, t h e s e requih-ements w e r e ~mp$ernented by iB gKaphite-EV3d@ratOP arrangement f e r which i t was assumed t h a t the moderator i n the c o r e and b l a n k e t zones would be removed every f o u r y e a r s s as a u n i t , and replaced w i t h a new III~ assembly. The r e f l e c t o r was designed f o r an i n i t i a l ~ U ~ ~ - V Q ~ L I fract i o n of I%, but w i t h o u t d e t a i l e d c o n s i d e r a t t o n of long-term changes due t o i r r a d i a t i o n e f f e c t s . The moderator d e s i g n will b e reexamined i n t h i s s u b t a s k and modified, as requi~ed,ts s a t i s f y t h e following needs: 8.

g r a p h i t e p i e c e s that can b e easily f a b r i c a t e d , c o a t e d if n e c e s s a r y , amd a d e q u a t e l y i n s p e c t e d b e f o r e w e in t h e r e a c t o r ,

g r a p h i t e p i e c e s , sub-assemblies, o r a s s e m b l i e s that can b e rep l a c e d with maximm safety (and w i t h r e a s o n a b l e e f f o r t and c o s t ) when t h e d e s i g n l i f e i s reached,

a g r a p h i t e r e f l e c t o r t h a t limits n e u t r o n leakage t o a c c e p t a b l e levels ana adequately p r o t e c t s t h e r e a c t o r vessel from fastn e u t r o n damage during its life,

a p p r o p r i a t e d i s t r i b u t i o n a d o r i f i c i n g Qf s a l t flows throughsut t h e core, and

v'"

h..

........ --

8-19 .?<a

p r o v i s i o n f o r r e g u l a t i n g and shutdown c o n t r o l rods as r e q u i r e d f o r o p e r a t i o n and s a f e t y .

In a d d i t i o n , t h e d e s i g n of t h e r e a c t o r vessel w i l l b e reviewed t o e n s u r e t h a t requirements of f a b r i c a b i l i t y and i n s p e c t a b i l i t y are m e t . The c o r e d e s i g n s t u d i e s w i l l b e supported by n e u t r o n i c d e s i g n c a l c u l a t i o n s ( i n Task 7.5.1) t o e n s u r e t h a t t h e d e s i r e d nuclear performance is m e t and by a d d i t i o n a l technology development work i f needs are i d e n t i f i e d . A reduced-scale o r a few-channel model of t h e c o r e may b e needed p r i o r t o t h e o p e r a t i o n of t h e NSTW rnockup t o h e l p demonstrate t h e adequacy of d e s i g n s o r t o examine t r a n s i e n t b e h a v i o r . Such a model, i f needed, would b e i n c o r p o r a t e d i n t h e Components T e s t F a c i l i t y (see S e c t i o n

10.12).

8.4.4.3

... :24

.&.

... .

Subtask 7.1.1.3

Primary system l a y o u t

The l a y o u t of t h e primary system i n t h e current r e f e r e n c e d e s i g n r e p r e s e n t s a compromise between minimram f u e l volume and a 30-year d e s i g n f i f e i n t h e f a c e of normal and abnormal stresses and stress c y c l i n g - w i t h additional c o n s t r a i n t s sf s i m p l i c i t y , i n s p e c t a b i l i t y , and m a i n t a i n a b i l i t y . En t h i s s u b t a s k , t h e r e f e r e n c e arrangement w i l l be reviewed t o d e t e r m i n e , f i r s t , i f t h e s e d e s i g n c r i t e r i a have i n fact been m e t . In particular, s t e a d y - s t a t e and t r a n s i e n t stress a n a l y s e s w i l l b e p e r f o m e d t o v e r i f y t h e estimate of d e s i g n l i f e . A l t e r n a t e Payouts w i l l a l s o b e examined t o determine whether s i m p l e r a n d / o r more economical arrangements can b e d e v i s e d . It has been sugg e s t e d , f o r example, t h a t p i p e and vessel l i n e r s i n h i g h - s t r e s s r e g i o n s might reduce thermal stresses and permit a more compact arrangement. The a t t e n d a n t s a v i n g i n f u e l i n v e n t o r y would, i n this case, have t o b e weighed a g a i n s t t h e added system complexity t o judge t h e v a l u e of such a concept. Such t r a d e s f f s will b e e v a l u a t e d folp t h i s and o t h e r l a y o u t s .

8.4.4.4

Subtask 7.1.1.4

System s t r u c t u r e and s u p p o r t

Tke s t r u c t u r a l d e s i g n of t h e major components and t h e methods f o r supp o r t i n g them i n s i d e t h e i n s u l a t e d and h e a t e d containment c e l l s r e q u i r e a d d i t i o n a l a n a l y s i s f o r the r e f e r e n c e d e s i g n MSBR. The proposed arrangement of s u s p e n s i o n from above appears t o o f f e r s i m p l i c i t y b u t may have The d i s a d v a n t a g e s i n terms of maintenance and seismic r e s t r a i n t . r e f e r e n c e and a l t e r n a t e d e s i g n s w i l l b e s t u d i e d i t a t h i s s u b t a s k t o ens u r e t h a t a v i a b l e concept i s adopted.

8.4.4.5

Subtask 7.1.1.5

R e j e c t i o n of r a d i a t i o n h e a t

I n t h i s s u b t a s k t h e major components of t h e r e f e r e n c e d e s i g n will b e examined t o determine whether h e a t g e n e r a t e d by n u c l e a r r a d i a t i o n i s s a t i s f a c t o r i l y r e j e c t e d , and t h e conceptual. d e s i g n s w i l l b e modified

8-18

where necessary to ensure such h e a t rejection. Both noma1 and o f f n O r I E d conditions W i l l be COTLSideKed. bn nO%tnalOperation, the p r h 6 f pal consideration is S U K ~ ~ Ct h~a S t are not naturally cooled by flowing salt - p o s i t i v e c o o l i n g must b e a s s u r e d , Under o f f - n o m 1 conditions, particularly when the primary c i r c u i t is drained, less heat way have to be rejected b u t its rejection is likely to be more difficult. (The heat sources in t h e d r a i n e d system asrise from decay of deposited fiss~on products.) m e primary heat exchan le of a component where some changes in conceptual design may be required in order to limit temperatures in t h e drained system, The drain-tank heat r e j e c t i o n system w i l l also b e carefully studied in this subtask. This system must operate effectively under all ~ o ~ n d i t and i ~ nslmuld ~ remain operable under even the most severe a c c i d e n t s . A variety of alternative system and c o o l a n t s w f l l be studied and t h e most promising combination §elected f o r

=.:.

the refeK@nc@de%ign. ......... -. .

8.4.4.6 ~ i t h o u g hnominal ehoiees have been estzmishea for a11 important features of the breeder c o n c e p t , there are several areas i n whish alternative p o s s i b i l i t i e s exist t h a t cannot y e t be eliminated from consideration. Among t h e more prominent areas of c h o i c e are the secondary csslant (noaninally so i m f l u s r o b o r a t e ) and the steam power c y c l e (nominally supercritical with 700°F feedwater). &Then alternatives are c o n s i d e ~ d , a§ i n Task. 4 . 2 . 6 f U K alternate C O U a a l a t s (see SeCtfOn 5 ) it Will be lleCesSi3.q to eX2JTLin@ t h e i P e f f € % C t S014 t h e COIlCE?pttad d e s i g n s f the system and components to p r o v i d e a basis f o r factoring such effects into assessments of t h e alternatives In t h i s s u b t a s k , p r e l i m i n a r y conceptual designs of components d subsystems will be generated to a ~ c ~ alternative ~ ~ ~ ac h o~i c ees of major system features. These designs will then be used in assessing the performance and econsmics of modified breeder concepts a

8.4.4.7

S u b t a s k 7.1.1.7

Demonstration reactor

men the bree e r CoIICept % S Sufficiently Well defined, i t W i l l b@ p Q S S i b f e to p r e p a r e a p r e l i m i n a q c o n c e p t u a l design f o r a demonstration reactor which will u l t i m a t e l y p r o v i d e t h e experience necessasry f o r design of COgarxleKCial r e a C t O % S . H O W e V e r , She@ Other C O n C e p t U d d e s i g n Work F a i l l b e i n p r o g r e s s (Task S . l . % > , t h e demonstration breeder will represent a concensus judgment of the most desirable system. Most features of t h e demsnstratisn system w i l l be like those of t h e Csn6ensus comercia1 system b u t this i s not a universal requirement. It m y be d e s i r a b P e , f o r example, to design the demsnstratfon plant f o r lower total power or f o r a s h o r t e r o p e r a t i n g life. However, it is anticipated t h a t much of the earlier conceptual design work w i l l be directly a p p l i c a b l e t o t h e demonstration ~ e a c t o r , The "finiiE" conceptual design will be used as a b a s i s f o r selecting desi C r i t e k - i t ? . f B P a test -PeaCtOK, Well as ts more clearly estimate t h e c o s t and schedule f o r t h e demo p l a m t .

8-19

En a d d i t i o n to the b a s i c , conceptual r e a c t o r s t u d y p i t i s d e s i r a b l e t o o b t a i n as much industrial input and particFpation i n t h e program as p o s s i b l e . IndustriaH o r g a n i z a t i o n s w i l l b e encouraged $8 participate i n t h e p%Bgrams and will be at least p a r t i a l l y supported through omh, subcontracts e

8.4.5.1 A s e p a r a t e c o n c e p t u a l d e s i g n f o r a 1BOB-MW(e) MSBR s h o u l d be developed by i n d u s t r y , probably through an 0 s u b c o n t r a c t . me design shsukd be s u f f i c i e n t l y complete t o i d e n t i unambiguously all major features of the reactor system, and s h o u l d be arrived at independently, b u t not necessarily by fgnorin previous work Considerable p r o g r e s s toward such a d e s i g n w a s made p r e v i o u s l y by an i n d u s t r i a l group5 under subcontract to 6mE; hm7ever, e d e s i g n w a s mot f u l l y developed. This work, and t h e results of 0 studies, could serve as a s t a r t i n g p i n e for f u r t h e r d e s i g n e f f o r t . After the d e s i g n is s u f f i c i e n t l y well e s t a b l i s h e d , i t shouid b e MI^ describes in a preiimnfnaq system Design D e s c r i p t i o n (SDD) and e v a l u a t e d i n terns of performance and ecsnsmics. mis d e s i g n and i t s analysis should be available b e f o r e El d e t a i l e d d e s i g n e f f o r t i s Undeb-taken f o r SUbSeqUent deVe%opTient O f MSR! 8 B

8.4.5.2 Although the c o n c e p t u a l desi,ms s h o u l d r e l y p r i m a r i l y on a v a i l a b l e technology, some c r e d i t s h o u l d b e taken f o r t e c h n i c a l developments which are expected $0 occur over t h e next t w o to f i v e years ( e . g . , demonstrations of M a s t e l l s y M s u i t a b i l i t y and chemical p r o c e s s i n g methods). D e s p i t e the taking of such credit, the detailed studies r e q u i r e d to p ~ o d u ~ane SDD can b e expected t o reveal inadequacies i n t h e e x i s t i n g technology, as it is a p p l i c a b l e t o PER'S. n e s e i n a d e q u a c i e s should be reduced to a recornended program of ~esearchand development which would be p ~ e pared and docmented in t h i s subtask.

8.4.5.3

Subtask 9.1.2.3

Safety a n a l y s i s

8-20

8.4.6

Task 7.1.3

O W L s t u d y of NSTR

A s a r e s u l t of t h e v a r i o u s s t u d i e s of MSBR's, i t should b e p o s s i b l e t o d e s c r i b e a "must probable" b r e e d e r reactor - t h a t i s , one that could b e designed, b u i l t , and s a f e l y o p e r a t e d w i t h a c c e p t a b l e b r e e d i n g and economic perfomance. Those s t u d i e s will also i d e n t i f y s p e c i f i c a s p e c t s of t h e teckn~lbogy t h a t should b e proved i n a demsnstration r e a c t o r and developed to the demonstration stage i n an MSTR. The purpose of t h i s s u b t a s k is t o evolve a conceptual design s f an WTR t h a t incorporates a l l the f e a t u r e s whose development and t e s t i n g are r e q u i r e d for the dE?E?.OnStratiQTlp l a n t .

The test r e a c t o r would p r o b a b l y b e designed t o operate a t a moderate p o ~ lee ~ v e l ( p o s s i b l y a few hundred thema1 megawatts) t o g e n e r a t e "breeder q u a l i t y q ' steam b u t n o t n e c e s s a r i l y e l e c t r i c i t y . The system would l i k e l y b e equipped with e x t r a i n s t r u m e n t a t i o n and t e s t i n g facili t i e s , along w i t h equipment f o r imposing t r a n s i e n t c o n d i t i o n s t h a t wou%d not usually b e encountered i n normal o p e r a t i o n . Breeding, as such9 would n o t have t o be a d e s i g n o b j e c t i v e s i n c e i t i s b e l i e v e d t h a t verif i c a t i o n of a p r e d i c t e d conversion r a t i o would demnstrate t h e adequacy of the neutr~nic design methods. Important d e s i g n o b j e c t i v e s would b e Operation at breeder d e n s i t i e s , TaeUtroll fltnxes, and tW2peKatUre d i f f e r e n c e s ; components would have t o be Parge enough t o t e s t d e s i g n techniques, manufacturing c a p a b i l i t y , and performance c h a r a c t e r i s t i c s .

8.4.7

Task 7.1.4

I n d u s t r i a l s t u d y of r n T R

8.4.8

Task 9.1.5

S t u d i e s of a l t e r n a t e d e s i g n s and uses of MSR's

From the s t a n d p o i n t s of r e s o u r c e u t i l i z a t i o n and o v e r a l l economy, the lfkely l o n g teHn ZippPicatiQn f 8 P mwpS%S t h e single-f%Uid b r e e d e r . Hmever, o t h e r d e s i g n s and uses shouPd b e examined t o d e t e m i ~ ewhether s h o r t e r - t e r m a p p l i c a t i o n s e x i s t f o r s i m p l e r , smaller, o r s p e c i a l purpose systems. Among t h e a l t e r n a t e s y s t e m to b e exmined c o n c e p t u a l l y i n t h i s task are low-power-density converters, simple plutonium b u r n e r s , and9 modest-size process heat systems. llKlSt

h..

.... gi.x

8-21

The b r e e d e r r e a c t o r r e q u i r e s p e r i o d i c replacement of h i g h - q u a l i t y moderator g r a p h i t e amd c ~ n t i n u o u so p e r a t i o n of a n i n t e g r a t e d , o n - l i n e c h e d c a l p r o c e s s i n g p l a n t . The d i f f i c u l t task of g r a p h i t e replacement could b e avoided i f t h e c o r e were s u f f i c i e n t l y l a r g e and t h e power d e n s i t y s u f f i c i e n t l y low to p e r n i t a 36-year g r a p h i t e l i f e ; and t h e o n - l i n e p r o c e s s i n g p l a n t c o u l d , in p r i n c i p l e , b e r e p l a c e d by p e r i o d i c batch r e p r o ~ e s s i n gof t h e f u e l on a cycle of a f e w years. The ~ t ~ ~ e r s i o n r a t i o for such a system would b e o n l y about 0.9 to 0 . 9 5 ( t h e low power d e n s i t y p r e v e n t s t h e b r e e d i n g rpatfo from d e c r e a s i n g as much as i t would i f only o n - l i n e p r ~ c e s s h gwere e l i m i n a t e d ) , although t h e capi t a l c o s t s could be s i g n i f i c a n t l y lower than f ~ t hr e b r e e d e r . T h i s syst e m would be examined t o d e t e r m i n e whether t h e a s s o c i a t e d power c o s t a would be s u f f i c i e n t l y a t t r a c t i v e to j u s t i f y f u r t h e r s t u d y . A s l i g h t l y s i m p l e r system could r e s u l t i f a r e a c t o r w e r e designed t o simply "burn" plutonium t h a t i s produced i n LWt'sg. It a p p e a ~ st h a t such b u r n i n g could be accomplished more cheaply i n MSK's than i n o t h e r systems, b u t such systems should b e examined more c a ~ e f u l l y .

The h i g h temperatures a t t a i n a b l e i n m a ' s may offer t h e p o s s i b i l i t y f o r process h e a t g e n e r a t i o n , amd s m a l l systems may o f f e r some advantages ~ Q m K u l t i p u r p o s e h e a t and power applfeatioms. Again, s t u d i e s should be made to e v a l u a t e t h e d e s i r a b i l i t y of developing MSW's f o r .... w

t h e s e purposes. 8.5

TASK GROUP 7 . 2

8.5.1

Objectives

DESIGN TECm0L5GY

The o b j e c t i v e s of t h e work i n t h i s t a s k group are t h e development of d e s i g n and ~ ~ K ~ O I - U X U Xc ~r i t e r i a f o r components, subsystems, and systems to be built i n t o MSR's and t h e de~elopg%nent of methods f o r analbyzing and d e s i g n i n g such i t e m s . Current d e s i g n d a t a and r e l a t e d i n f o m a t i o n w i l l b e maintained and documented as r e q u i r e d . 8.5.2

Schedule

Same work i s c u r r e n t l y being done i n t h f s task group and consfderpab3-y

b e r e q u i r e d as t h e d e s i g n c h a r a c t e r i s t i c s of %R's evolve from the work i n Task Group 7.1. T h i s work i s expected t o c o n t i n u e throughout t h e t i m e span of t h e MSR program. The breakdown ~f t h e e f f o r t among t h e v a r i o u s t a s k s and s u b t a s k s i s s h o r n in T a b l e 8.5.2.

IBOK~w i l l

... .... s a

,..:a

8 5.3 a

Funding

Although t h e work i n t h i s task group extends over a long t i m e p e r i o d , t h e l e v e l of e f f o r t , as shown 5mn Table 8 . 5 . 3 , i s r e l a t i v e l y modest; a number of t h e t a s k s r e q u i r e only p a r t - t i m e e f f o r t . The p r i n c i p a l effort is a s s o c i a t e d w i t h t h e development and formaHization of d e s i g n c r i t e r i a and methods.

-”

.- _ __--.

Table

7.2.1

7 .Pe 2

7-2.3

7.2.4

7.2.5

Total

8.5.3.

Estab%ish ment fcx 7.2.1.1 7.2.1.2

design l%oO°F Design Design

Subtotal

7.2-l

Compile 7.2.2.1 7.2.2,2 7.2.2.3 7.2.2.4 7.2.2.5

desbp properties Fuel salt Coolant salt Graphite I-IastePPay N Other reacmr

Subtotal

7.2.2

DasPgn i3)CSXS.W compipillation analysis

reports

Raactor

~QP

%und

for

for 1QQQ

Group

20 -

65 32 -

50 -

5 4

5 4 3 4 4

3 % 2 2 2

2 3 3 3 2

sdeeted

Task

7.2

Design

techn~Llogy

dollare)

equip-

2 2 a 2 2

2 2 2 2 2

I.0

32 -

32 .-

32 -

I.57

23Q

a72

141

7.5

and

in%ormation -~~--

funds

requirements (casts in

materhals

0% CQst data 63% pPant costs

MoPten-Sal& t3y5tC%il operating

bases operation criteria methods

(qserating

Task

Group

7.2

8-24

8.5.4

Task 7.2.1. E s t a b l i s h d e s i g n bases and methods f o r equipment for l30Q'P o p e r a t i o n

This t a s k i n v o l v e s p r i n c i p a l l y , two a c t i v i t i e s . The f i r s t i s t h e development sf d e s i g n and performance c r i t e r i a f o r equipment which w i l l o p e r a t e a t the h i g h e r temperatures and t h e second i s t h e development of d e s i g n methods f o r meeting t h e c r i t e r i a .

8.5.4.1 The c o n c e p t u a l d e s i g n s of PlSR s y s t e m w i l l e s t a b l i s h t h e service condit i o n s and many of t h e performance requirements f o r t h e r e a c t o r equipment, ine%ud$ng such i t e m as chemical environment, t e m p e r a t u r e , P P ~ S S U K and ~ ~ material %Pow rates. Under this s u b t a s k , t h e r e l e v a n t requirements f o r each component or system w i l l be assembled and compiled into a s e t sf d e s i g n c r i t e r i a . This work will b e done i n c l o s e c o o p e r a t i o n w i t h t h e d e s i g n and development e f f o r t s t o e n s u r e t h a t r e a l i s t i c c r i t e r i a are e s t a b l i s h e d which m e e t t h e d e s i g n weeds and are c a p a b l e of implementation

8.5.4.2

Subtask 7 . 2 . 1 . 2

Design methods

Muck of t h e equipment in an MSR w i l l b e expected to o p e r a t e f o r up t o 36 y e a r s a t c o n d i t i o n s which are near t h e l i m i t s of a p p l i c a b i l i t y of c u r r e n t design methods. Work i s c u r r e n t l y b e i n g done i n o t h e r USAEC programs ( n o t a b l y the WFBR and HTGR programs) t o develop methods f o r (1) d e s i g n i n g equipment f o r long-term high-temperature service, and (2) analyzing d e s i g n s to demonstrate t h e i r adequacy. To t h e maximum e x t e n t p o s s i b l e , these methods w i l l b e adopted and a p p l i e d to MSR program needs. A d d i t i o n a l work w i l l b e done t o extend t h e range of capab i l i t y i f i t i s r e q ~ i b - e dand t o demonstrate a p p l i c a b i l i t y of t h e methods t o materials ana components of i n t e r e s t to PER'S.

8.5.5

Task 7.2.2

Compile d e s i g n p r o p e r t i e s

A complete, a c c u r a t e , and c u r r e n t s e t OS d e s i g n - r e l a t e d p r o p e r t i e s of all materials of i n t e r e s t in PER s y s t e m must b e maintained. These w i l l b e used e x t e n s i v e l y i n developing c o n c e p t u a l d e s i g n s for components and s y s t e m and i n d e f i n i n g needs f o r equipment and technology development. Conversely, t h e d e s i g n and development e f f o r t s w i l l h e l p to e s t a b l i s h needs f o r s p e c i f i c p r o p e r t i e s and t h e accuracy requirements. This task p r o v i d e s for t h e c o m p i l a t i o n of t h e r e l e v a n t d a t a and i t s d i s t r i b u t i o n to llg€?Ps w i t k i n the p r o

8.5.5.1

Subtask 9.2.2.1

Fuel. s a l t

P r o p e r t i e s of t h e n ~ m i n a lf u e l salt are f a i r l y w e l l e s t a b l i s h e d , and dl p h y s i c a l and cheaical p r o p e r t i e s t.7111 be t a b u l a t e d and made availa b l e to the p r o s p e c t i v e users.

15511

8-25

8.5.5.2

Subtask 7.2.2.2

Coolant s a l t

There i s u n c e r t a i n t y concerning t h e optimum c o o l a n t - s a l t composition, and f o r some t i m e t h e p r o p e r t i e s of s e v e r a l a l t e r n a t e secondary c o o l a n t s w i l l b e considered. P r o p e r t i e s of t h e c o o l a n t t h a t i s f i n a l l y chosen w i l l b e c o l l e c t e d as t h e y become a v a i l a b l e .

8.5.5.3

Subtask 7.2.2.3

Graphite

"he q u a l i t y of t h e g r a p h i t e used i n an MSR has a d i r e c t b e a r i n g on t h e r e a c t o r p l a n t design. I s o t r o p i c g r a p h i t e w i t h good radiation-damage r e s i s t a n c e w i l l allow t h e power d e n s i t y i n t h e r e a c t o r to b e h i g h e r and t h e r e f o r e w i l l , by lowering t h e s p e c i f i c f u e l i n v e n t o r y , tmprove t h e n u c l e a r performance of t h e p l a n t . A l s o , low p e r m e a b i l i t y ( c o a t e d ) g r a p h i t e w i l l improve t h e n e ~ t r o neconomy by Powering n e u t r o n Posses to xenon. Tlie c h a r a c t e r f s t f c s of p o t e n t i a l g r a p h i t e s f o r K S R ' s w i l l be t a b u l a t e d and made a v a i l a b l e . Needs f o r a d d i t i o n a l data w i l l b e determined.

8.5.5.4

Subtask 7 . 2 . 2 . 4

Hastelloy N

'Fhe s t r u c t u r a l a l l o y f o r t h e MSW primary s a l t c i r c u i t i s expected t o be a modified H a s t e l l o y M whose development i s d i s c u s s e d in S e c t i o n 2. When the r e f e r e n c e a l l o y has been a d e q u a t e l y t e s t e d and pr5venr i t s p r o p e r t i e s ( s t r e n g t h , c r e e p c h a r a c t e r i s t i c s , thermal p r o p e r t i e s , r a d i a t i o n r e s i s t a n c e , e t e . ) w i l l b e c o l l e c t e d i n a form s u i t a b l e f o r t h e r e l e v a n t d e s i g n work, i n c l u d i n g t h e d e s i g n of developmental i t e m .

8.5.5.5

Subtask 7.2.2.5

Other r e a c t o r materials

P h y s i c a l and chemical p r o p e r t y data must a l s o b e compiled f o r a v a r i e t y of o t h e r materials of i n t e r e s t i n MSR's. S t r u c t u r a l materials other than W a s t e l P ~ yN may b e s e l e c t e d f o r p o r t i o n s 0% t h e primary and secondary s y s t e m ; r e a c t o r c o n t r o l materials w i l l b e needed; s p e c i a l materials may b e s p e c i f i e d f o r valve s e a t i n g and b e a r i n g s u r f a c e s ; and many o t h e r mater i a l s w i l l b e needed.

8.5.6

....

Li.yA

Task 7.2.3

Design r e p o r t s on s e l e c t e d MSW s y s t e m

Hn a m o l t e n - s a l t b r e e d e r p l a n t , as i n any r e a c t o r p l a n t , t h e r e are many s u p p o r t i n g systems t h a t must b e s p e c i f i e d and designed. A s t h e s e s y s t e m become i d e n t i f i e d and c o n c e p t u a l d e s i g n s are completed, t h e systems w i l l b e d e s c r i b e d i n autonomous d e s i @ r e p o r t s which emphasize t h e performance requirements and c r i t e r i a . S y s t e m i n this c a t e g o r y i n c l u d e t h e a u x i l i a r y power system, the a f t e r - h e a t removal system, and t h e f i s s i o n - p r o d u c t h a n d l i n g system. En many cases, r e p o r t s on t h e s e systems w i l l c o n s t i t u t e a b a s i s f o r f u r t h e r d i s c u s s i o n i n d r a f t SBB's.

8-26

8.5-7

Task 7 . 2 . 4

Compilation of c o s t d a t a and a n a l y s i s of p l a n t c o s t s

%e a n t i c i p a t e d c a p i t a l and o p e r a t i n g c o s t s of commercial MSBRss are expected t o be important f a c t o r s i n guiding development a c t i v i t i e s w i t h i n t h e MSW p r o g ~ a m . Moreuver, s i n c e MSBR c o s t s are likely t o b e compared w i t h c ~ s t sof other energy s y s t e m , i t i s e s s e n t i a l t h a t c o s t estimates b e as r e a l i s t i c as p o s s i b l e and t h a t they a c c u r a t e l y r e f l e c t the availa b l e technology. Thus, capital and o p e r a t i n g c o s t estimates w i l l b e made as e a r l y as the c o n c e p t u a l d e s i g n s are s u f f i c i e n t l y advanced, and the estimates w i l l be updated and r e f i n e d as n e c e s s a r y t o i n c o r p o r a t e a d d i t i o n a l i n f o m a t i o n t h a t has been developed. E s t a b l i s h e d procedures w i l l be used f o r estimating c o s t s so t h a t the r e s u l t s will be s u i t a b l e f o r comparisons w i t h estimates f o r o t h e r systems. I n a d d i t i o n t o t h e cost estimates f o r r e f e r e n c e c o n c e p t s , data w i l l be g e n e r a t e d to permit e c o n ~ m i ce v a l u a t i o n s of t r a d e o f f s a s s o c i a t e d w i t h v a r i o u s d e s i g n altern a t i v e s ( e . g . , higher-coat secondary c o o l a n t vs. s i m p l e r o r less expensive equipment i n the secondary system) 8.5.8

Task 7.2.5

Molten-salt r e a c t o r i n f o r m a t i o n system

A computerized d a t a set c o n t a i n i n g a b s t r a c t s of a l a r g e number ( c u r r e n t l y 373) of ~ s ~ - r e b a t e dd o c ~ e n t sis on f i l e a t OaU%. This d a t a s e t , d e s i g n a t e d XSRIS ~ Q Molten-Salt P Reactor I ~ - ~ f ~ m a t iSystem, on was established t~ p r o v i d e program p a r t i c i p a n t s w i t h a r e a d i l y a c c e s s i b l e , computersearchable s u m a r y of most of t h e t e c h n i c a l i n f o m a t i o n that i s d i r e c t l y relevant to M s R ' s . ~ l t h o u g hno complete documents are stored i n t h e system, i n f o m a t i o n i s provided about t h e s o u r c e s and a v a i l a b i l i t y of documents. This system, which can be made a c c e s s i b l e ( v i a telephone) t o q u a l i f i e d p a r t i c i p a n t s o u t s i d e Q"J%, will be updated on a c o n t i n u i n g b a s i s t o e n s u r e maximum u t i l i t y of t h e i n f o r m a t i o n .

8.6

8 6 H a

TASK GROUP 7 . 3

CODES AND S T M B N S

Obj ectives

Codes and s t a n d a r d s f o r t h e d e s i g n , COnStruCtiQn, o p e r a t i o n , a d maintenance of ~ U C ~ ~ power E X reactors have been ana c o n t i n u e t o b e under development throughout t h e n u c l e a r i n d u s t r y . Kany of these are g e n e r a l l y a p p l i c a b l e t o ala n u c l e a r systems, including XSR's, b u t many u t h e r s are a p p l i c a b l e only t o s p e c i f i c r e a c t o r t y p e s . Regardless of t h e i r range of a p p l i c a b i l i t y , t h e u l t i m a t e purpose of such s t a n d a r d s i s the same - t o e n s u r e adequate s a f e t y and r e l i a b i l i t y in t h e s y s t e m t o which they a r e a p p l i e d . The o b j e c t i v e of t h e work i n t h i s task group i s t h e e s t a b l i s h m e n t of such s t a n d a r d s and codes, s p e c i f i c a l l y a p p l i c a b l e t o MSR's, as may be r e q u i r e d CE d e s i r a b l e t o e n s u r e f o r X S R $ s the s m e l e v e l s of s a f e t y and r e l i a b i l i t y that are r e q u i r e d i n ~thea:r e a c t o r systems.

I... LL%

8-27

8.6.2

Schedule

The i n i t i a l work of e s t a b l i s h i n g needs fer s t a n d a r d s and preparing prel i m i n a r y c r i t e r i a could begin i m e d i a t e l y , b u t , as shown i n Table 8.6.2, no direct e f f o r t i s a n t f c i p a t e d b e f o r e f;4e 1 9 7 9 . This work would cont i n u e f o r t h e d u r a t i o n s f t h e program w i t h t h e TEI-~QP emphasis seebarring when material code cases are prepared and when s t a n d a r d s are s e t prior t o the d e s i g n and c o n s t r u c t i o n of s p e c i f i c n u c l e a r f a c i l i t i e s o r major developmental facilities.

8 6 3

Funding

A s i n d i c a t e d i n Table 8 . 6 . 3 , the funding f o r t h i s work w i l l remain a t a low l e v e l u n t i l FY 1379, when a code case w i l l b e prepared f o r modified Hastelhoy N. A s work r e l a t e d t o modified Hastelloy N i s completed, that s u p p o r t will decline, b u t a d d i t i o n a l s u p p o r t will be r e q u i r e d to develop p r e l i m i n a r y standards f o p t h e MSTR and f o r the demonstration r e a c t o r , and f o r u p g ~ a d i ~ sand g refining the r e s u l t i n g standards.

8.6.4

Task 7.3.1

Standards f o r MSTR

The MSR is c u r r e n t l y unique among U.S. power r e a c t o r s i n the use of a c i r c u l a t i n g l i q u i d fuel and an on-line f u e l groceasimg f a c i l i t y . FOP t h e s e and s t h e r K ~ ~ S B ~many B , standards may have to b e nodiffed, o r generated for ~ - ~ S H I ' S fo ; r example:

S b c e r a d i o a c t i v i t y is dispersed t ' k r o u g h ~ u tt h e primary system, MSR primary s y s t e m may b e ~ e q u i k e e lto have Power l e a k a g e rates.

4, ..... .?y&

Standards f o r poSt-&Utdom C O S k b g should be modified to reflect the f a c t t h a t most of t h e afterheat is released in t h e drain tank after a d r a i n and t h a t t h e f u e l s a l t provides c o n s i d e r a b l e thermal inertia

1986

7.3.2

PKepasatioLan MSBR * s

standards

7.3.3

PKepaKatiQn

cads

cases

far

Table 8.6.3.

Operating

1975 7.3.1 7.3.2

Preparation Molten-Salt

of standards Test Reactor

for

Preparation

of standards

for

funds required far Task Group 7.3 - Codes and standards (costs in 1000 dollars)

11976

Fiscal

year

1977

I.978

1979

1980

1981

1982

1983

1984

1985

128

200

130

150

200

MSBR’S

7.3.3

Preparation

Total operating 7.3

of code cases funds

for

Task Group

-~------

128

192

200

13Q

130

1986

8-30

After a t h ~ ~ ~ review u g h of a v a i l a b l e s t a n d a r d s and t h e i r a d a p t a b i l i t y to M S R ~ ~needs , for modified or a d d i t i o n a l standards w i l l be i d e n t i f i e d and preliminary V ~ K S ~ Ow ~i l Sl be produced f o r a p p l 2 c a t i ~ nto the KSTR. The d e s i g n , c o n s t m c t i o n , t e s t i n g , o p e r a t i o n , and maintenance of t h a t K e a C t O l r will p r o v i d e tests of the adequacy of the s t a n d a r d s , as well as of t h e a b i l i t y s f NSR systems t o conform t o r e q u i r e d standards.

c he standards andl codes developed f o r t h e MSTR will b e reviewed and r e v i s e d t o meet t h e needs of t h e ~ ~ m e r ~MSBR. i a l This work will b e based on the i n f o r m a t i o n and e x p e r i e n c e developed in p r e p a r i n g e a r l i e r v e r s i o n s of s t a n d a r d s and the e x p e r i e n c e o b t a i n e d ~ P Q I I Ia p p l y i n g them t o t h e E T R . The usual seview, t r i a l use, and h - e v i s i ~ nprocedures w i l l b e employed i n establishing MSB

8.6.6

Task 7 . 3 . 3

Preparation of code eases

KastelEoy N w a s used i n t h e c o n s t r u c t i o n of the F b l t t ~ n - S a P t Reactor Experiment which was o p e r a t e d a t O m between 1965 and 1969, and a code case w a s submitted t o cover t h a t a p p l i c a t i o n . Before the n e x t reactor can be built, additional code cases must b e prepared f o the ~ modified Hastellay N which will be used. A case must b e s u b m i t t e d to o b t a i n a p p r o v a l of t h e material as ~ e g a ASME ~ d ~B o i l e r and Press~h-e Vessel code s e c t i o n 111, Case I, S e c t i o n VHII, and t h e h i g h temperatuse a p p l i c a t i o n cavered i n 1331-8, a s well as the special s e c t i o n af RDT' s t a n d a r d E-15-2.

It will probably require about two years of f u r t h e r study of t h e modif i e d a l l o y b e f o r e i t will b e p o s s i b l e t o f i n a l i z e its fornulation. I t is anticipated t h a t t w o additPcma1 years will be r e q u i r e d t o o b t a i n d a t a from large comericaP heats of t h e material and ta prepare t h e code case (see Section 2 , Task 1 . 4 . 3 ) . A d d i t i o n a l code cases are a l s o l i k e l y t o b e r e q u i r e d . For e x m p k 9 t h e p r i m a r y materials f o r t h e fuel pracessing plant a r e probably n o t covered by existing cases, and other materials that may be selected m y ~ e q u i r e s p e c i a l COnsideratiQla due to t h e nature Of t h e prC3pQSed % p p ~ i C a t i O n S . Such cases will be p r e p a r e d and su i t t e d as r e q u i r e d t o o b t a i n t h e a p p r o v a l s neeaea f o p the ph-ogrm.

TASK GROUP 9.4

8 7 e

8 ? 1 e

S b j ective

LICENSING OF MS

b..

&,.

8-31 r e a c t o r s . It i s , t h e r e f o r e , e s s e n t i a l t h a t t h e f i r s t p l a n t to which t h e s e c r i t e r i a are a p p l i e d , t h e MSTR, b e designed to comply w i t h all P i c e n s i n g r e q u i r e m e n t s , o r a t Peast t h e i n t e n t of t h e requirements. Since MSR's e x h i b i t fundamental d i f f e ~ e n c e sfrom s o l i d - f u e l e d r e a c t o r s , some sf t h e requirements may have t o be " i n t e r p r e t e d " t o make them a p p l i c a b l e t o MSR'ss. It is the purpose of t h i s task group t o exmine t h e l i c e n s i n g p o s i t i o n s of t h e c o n c e p t u a l MSR's Pn s u f f i c i e n t d e t a i l t o p r o v i d e r e a s o n a b l e a s s u r a n c e t h a t l i c e n s i n g a p p l i c a t i o n s can b e a c t e d upon f a v o r a b l y .

8.7 2 0

ScheduP@

The l i c e n s i n g s t u d y should b e g i n after a r e s o n a b l y f i r m conceptual d e s i g n has been e s t a b l i s h e d f o r t h e Y&BR i n PY 1978 and will c o n t i n u e through FY 1985 i n o r d e r to a l l o w review w i t h feedback t o t h e d e s i g n and development e f f o r t t o c o n t i n u e u n t i l t h e s t a t e of the technology i s such t h a t a "triaB" license a p p l i c a t i o n can b e prepared. Depending on t h e r e s u l t s of t h a t e f f o r t , a d d i t i o n a l work would probably be r e q u i r e d t o s u p p o r t t h e a p p l i c a t i o n far amd r e c e i p t of t h e c o n s t r u c t i o n permit and o p e r a t i n g a p p r ~ v a Pfor t h e MSTR. The a c t u a l p r e p a r a t i o n of a p p l i c a t i u w s f o r s p e c i f i c plants a r e n o t i n c l u d e d i n t h i s t a s k g ~ o u p .

8.7.3

The funding ~ O Kthis t a s k group, Table 8 . 7 . 3 , i s t e n t a t i v e l y set a t a low l e v e l w i t h a d d i t i o n a l s u p p o r t t o p r e p a r e t h e " t r i a l t va p p l i c a t i o n and to assist i n t h e MSTW a p p l i c a t i o n s . A s t h i s work proceeds, i f a d d i t i o n a l needs are i d e n t i f i e d , it will b e necessary t o i n c r e a s e t h e s u p p o r t f o r t h i s task group.

8.9.4

Task 7 . 4 . 1

S t u d i e s of MSBR l i c e n s i n g p o s i t i o n

The requirements f o r n u c l e a r plant l i c e n s i n g w i l l b e c a r e f u l l y reviewed t o i d e n t i f y any areas in which s p e c i a l i n t e r p r e t a t i o n s may b e needed to a c e o r n o d a t e the unique f e a t u r e s of PISBR's. A f t e r development of any such i n t e r p r e t a t i o n s , t h e MSBR c o n c e p t u a l deafgn w i l l b e examined t o d e t e r m i n e t h e e x t e n t t o which i t complies w i t h l i c e n s i n g requirements and t o ident i f y any f e a t u r e s t h a t might Kequire a d c l i t i o ~ ~ development l o r modificat i o n t o enhance l i c e n s a b i l i t y . When t h e d e s i g n and t h e technology are judged t o b e s u f f i c i e n t l y w e l l e s t a b l i s h e d , a t r i a l set of l i c e n s i n g documents, i n c l u d i n g a d r a f t PSAR, would b e prepared. These documents would not b e as ~ ~ ~ ~ p ~ e h eas n sthose i v e needed for a formal l i c e n s e a p p l i c a t i o n , b u t t h e y shouPd be a d e q u a t e to d e f i n e t h e b a s i c l i c e n s i n g p o s i t i o n of t h e reactor. These documents would b e reviewed w i t h i n t h e ~ P B ~ K E E I I and , an a t t e m p t would be made to o b t a i n review by l i c e n s i n g a g e n c i e s . Based on t h e r e s u l t s of such K w i e W S a d d i t k m a l work probably will be r e q u i r e d to f u r t h e r enhance t h e l i c e n s i n g position s o t h a t t h e r e can b e r e a s o n a b l e a s s u r a n c e t h a t t h e MSTR can be approved f o r o p e r a t i o n .

Table

8.7.3.

Operating

funds

required for Task Group 7.4 - Lisensing (sc9sts in mQQ dollars)

1977 7.4.1 Total

Studies position

of FfsBW llsensfng

operating

funds

for

Task Group

7.4

FPssaf

year

af MSR's

1978

1979

198Q

19 81

1982

1983

19 $4

I.0 85

32 _ 32

128 __l 128

192 192

25Q 2.58

200 2QO

280 2QQ

280 ~ 200

200 2QQ

1986

8-33

8.8

TASK GROUP 7.5

NUCLEAR ANALYSIS OF MSR POWER PLANTS

8.8 .I Objectives The objectives of the work in this task group are t~ provide workable neutronic designs for molten-salt reactor concepts under s t u d y and to determine the steady-state and transient p e r f o r m n c e characteristics of the designs. The design goals, in terms of breeding or conversion, fuel-cycle performance, power densities, neutron fluxes, physical size, etc., will be established by other design activities. This task group also provides for the development of calculational methods that may b e needed to produce results with the required degrees of accuracy and precision.

8.8.2

Schedule

Neutronic studies (see Table 8.8.2) will be initiated along with the start of other preliminary conceptual design activities and will continue for t h e duration of the design studies t o permit needed adjustments and refinements of the conceptus% designs. The required level of effort is expected to be relatively low except for brief periods when studies of new or alternate concepts are initiated. At those times, additional effort w i l l be expended to support the extra design work.

8.8.3 Funding

The funding required t~ support the anticipated nuclear analysis work is shown in Table 8.8.3. 8.8.4

Task 7.5.1

Analysis of 1808-M'W(e) MSBR's

Computer codes and methods f o r static nuclear analyses of 'PISBR's are fairly wela established, but as these studies continue, the codes will be revised as necessary and cross-secti~nlibraries updated. All analyses of MSBR's will be made t o optimize one or more design parameters. Studies will include optimization of fuel-cycle cost, breeding perfornaanee, fuel inventory, doubling time, and chemical processing rate. These studies will also provide data on core reactivity coefficients and other properties that are important in the reactor kinetic behavior. Additional computations will then be made to define the kinetic response of the core to anticipated transient conditions. The models used for such computations and some of the results wfll be incorporated in more comprehensive models to examine the dynamic behavior of entire MSBR systems 0

....

<;a

... .... >m

~ / --I I _.-._ -.. _..+---.

i I

_-_

-i --..-I

I I

I ! ,

/ I

Table 8.8.3.

Operating fund requirements fog. Task Group 7.5 - NucleaK analysis of MSR pawer plants (costs in PQQQdiollars)

7.5.1

Analysis of lQOQ-W(e) MSBR’S

7.5.2

eontPol

stuaies

7.5.3

Analysis

of aPteKnate PER designs

7.5.4

Computer code development 7.5.4.1 static reactor

Total

30 32 -

30 32 95

60 64

of MSBR plants 40

CdCUlat%OlX3

7.5.4.2

Dynamic ?reactsr calculations

Subtotal

7.5.4

opesating

costs for Task Gmup 7.5

1.2

100

828

8-36 8.8.5

Task 7 . 5 . 2

Control studies of MSBR plants

Control studies of these plants involve many areas. With respect to neutronic processes, experience with n o experimental PER'S showed that they w e r e easily controlled, amd t h i s is expected to be the case f o r Larger cores. However, plant control invoS1ves a great deal of interaction between the meutronic pr~cessesand other parts s € the system. These interactive control processes f o r steady operation, noma1 mneuverinpg, and upset conditions w i l l be extensively studied with the aid of analog, hybrid, and digital computer techniques to ensure that the conceptual designs provide adequate3.y for control needs. This task interfaces strongly with Task Group 11.1 (see Section 1 2 ) . 8.8.6

Task 7 . 5 . 3

Analysis of alternate NSR designs

Alternate MSR's are of two basic types9 converters and plutonium b u r n e r s . A uranium burner which uses no fertile thorium is of course possible, b u t would probably have little practical use. It is believed preferable t o incorporate t h o r i m in a uraniw-fueLed reacto~and achieve some conVekSiCKl. NQn-bpeeder t y p e s Sf P/iSR's W o d d be inTPeStPgati3d in U K d e k to determine their probable economic impact. h a l l y s e s would be done to determine fuel-cycle c o s t s and the performance of ~ e a c t ~ rdesigned s for maximaun simplicity and m i n i m m capital c o s t . There are potential uses f o r NSR's other than central station power generation. Many industries require Parge quantities of process steam at temperatures which suggest t h e use of MSR's f o r s t e m production. A parametric s t u d y of reactors of various sizes wouLcl be made to determine the economics of heat s o u r c e s of this type. liraalyses of these alternate Mshz's will be done following the breeder analyses, since MSBR development comprises the main line effort of the program.

.8.7.1

Task 7.5.4

Computer code development

Subtask 7.5.4.1

Static calculations

Currently available methods for performing reactor statics calculations a p p e a r to be adequate f o r MSR conceptual design purposes, and mo development of statics codes, p e s~e , is anticipated. A general design code (RQB) is ~ S available Q to perfsm parameter and fuel cycle studies. 'phis eode could b e m d i f i e d to a two-difpeta~i~~1a3. model in o r d e r to b e t t e r ana-= lyze a multi-region reactor core. While the EpaDP cross-section library i s expected to be adequate f o r design calculations, sensitivity analyses would be done to determine the effect OB ~ ~ U ~ K O X economy - I of uncertainties in the cross section data.

m .:.

8-37 8.8.7.2

Subtask 7.5.4.2

Dynamic reactor calculations

It is p o s s i b l e that additional cedes w i l l be needed to handle the k i n e t i c dynamic analyses t h a t w i n b e needled 601- large N S R ' S ~ here are mngi transient and off-design calculations f o r wRich nuclear analyses must b e performed, and t h i s task provides f o r the development of programs to supp l y the analysis capability. BT

.... ... d

~.&

.:.+:... .:j .~.

8-38

Ebasso Services, h e . , "1000 m(e) ~ o l t e nSalt Breeder Reactor Conceptual Design Study: F i n a l Report - Task 1,'' February 1972.

9.1

INTRODUCTION

The g r a p h i t e in 8 SiRgle-fluid MSBa S e % V e § S2Q s t r u @ t u r a %pUKp5se o t h e r t h a n to d e f i n e t h e f l o w p a t t e ~ n sof t h e s a l t and, of course, to support f o r c e s resulting from i t s own weight and ~~ometatum t r a n s f e r from the flowing salt. The requirements on the material are d i c t a t e d nost s t r o n g l y by nuclear c o n s i d e r a t i o n s , namely s t a b i l i t y of t h e material a g a i n s t r a d i a t i o n - i n d u c e d d i s t o r t i o n , n o n p e n e t r a b i l i t y by t h e f u e l - b e a r i n g molten s a l t , and RQnEIbsorption of xenon i n t o t h e g r a p h i t e . The p r a c t i c a l l i m i t a ~ ~ O Rora S meeting t h e s e requirements i n turn impose conditions on t h e core d e s i g n , s p e e i f i e a ~ ythe neseasity t~ p r o v i d e 90% pe-rioaic g r a p h i t e replacement and t o l i m i t t h e c r o s s - s e c t i o n a l area of t h e g r a p h % t e prisms.

The primary o b j e c t i v e s of t h i s a c t i v i t y are t o c i e ~ e l ~ap core moderator g r a p h i t e having good dimensional s t a b i l i t y under n e u t r o n i r r a d i a t i o n and a Pow p e r m e a b i l i t y t o 13%Cewhich can be produced c o m e r c f a l l y a t an acceptable cost

9.1.2

Scope

The scope of t h i s work w i l l i n c l u d e s t u d i e s of a b a s i c na%ure ~ o n c e r ~ i n g damage mechanisms, f a b r i c a t i o n studies to develop graphite w i t h improved d f m g n ~ i i ~ n as tl a b i l i t y , development of s e a l i n g methods f o r reducing the p e r m e a b i l i t y of the g r a p h i t e t o 135Xe9 and measurements of t h e p h y s i c a l p r o p e r t i e s of g r a p h i t e s having potential f o r MSBB application. 9.1.2.1

Task Group 8.1

Basic graphfee s t u d i e s

These s t u d i e s will be eo~~erzned w i t h basic i r r a d i a t i o n damage mechanisms i n g~aphite. S i n g l e c r y s t a l s w i l l b e used t o d e t e r d n e the t y p e s and numbers of defects produced during i r r a d i a t i o n . Annealing kinetics w i l l be observed by t r a n s m i s s i o n e l e ~ t ~ ~ ~ ~ ~ i . c r ~ s c o p y . 9.1.2.2

Task Group 8.2

G r a p h i t e b a s e stock developnent

This work will ~ R V O P V a ~s t u d y of the basic raw materials and f a b r i c a t ion prscesses used i n making g r a p h i t e . C ~ ~ ~ ~ i ~ eand ~ c lekx pa el r i m e n t a l graphites w % l l Be c h a r a c t e r i z e d and i ~ r a d i a t d ,and dimensional and physical p r o p e r t y ~91a-e~will b e measured. The goal w i l l b e to C O ~ X - ~ l a t e s t a r t i n g material amd f a b r i c a t P s n variables with dlbrrtensianal stability d u r i n g i r r a d i a t i o n . ;s!&

...

9-1 .... .... ........, . I

y "a '. <

9-2

9.1.2.3

Task Group 8 . 3

Sealing of g r a p h i t e f o r p e r m e a b i l i t y r e d u c t i o n

TIE a b s o r p t i o w of 135xe by the care g r a p h i t e can r e s u i t in r e a u c t i o n of the b r e e d i n g r a t i o . Most of the I 3 % e will b e removed from t h e f u e l s a l t by c o n t a c t of t h e s a l t with helium, b u t i t w i l l l i k e l y be n e c e s s a r y to reduce t h e p e r m e a b i l i t y of t h e g r a p h i t e t o p r e v e n t a b s o r p t i o n sf xenon by the g r a p h i t e . E t i s l i k e l y that g r a p h i t e w i t h s u r f a c e permea b i l i t i e s as l o w cm2/sec w i l l b e r e q u i r e d , and t h i s pemeab i l i t y can only be o b t a i n e d by (a> surface c o a t i n g t h e g r a p h i t e w i t h pyocarbon, (b) impregnating t h e g r a p h i t e w i t h carbon, o r ( e > impregnating the g r a p h i t e With s a l t . s$%k Of these teChniqUf2S W i l l be pursued to some e x t e n t . 9.1.2.4 The p h y s i c a l properties of g r a p h i t e cover a wide r a n g e of v a l u e s due t o t h e large number of s t a r t i n g mterials ana fabracation t e c h n i q u e s used i n making g r a p h i t e . The p h y s i c a l p r o p e r t i e s of g r a p h i t e p r o v i d e useful infGlXX3fiion &OUt the c r y S t a l l o g r a p h i C StKUctUPe and Other p?ZCIpertieS. Similarly, the changes in p h y s i c a l properties d u r i n g i r r a d f a t i s n p r o v i d e i n f s m a t i o n about the c r y s t a l l o g r a p h i c changes t a k i n g p l a c e . Thus p h y s i c a l p r o p e r t i e s suck as thermal expansiart, thermal cowduct$vity, and e l e c t r i c a l r e s i s t i v i t y a r e v e r y useful f o r c h a r a c t e r i z i n g g r a p h i t e s and f o r e v a l u a t i n g s t r u c t u r a l changes d u r i n g i r r a d i a t i o n . The changes o f these propertfes ELK^ also of d i r e c t importance to the design of a r e a c t o r core, s i n c e t h e y affect d i ~ ~ ~ e ~ s i behavior onal and h e a t t r a n s f e r . Work will be c a r ~ i e c lout in w h k h g r a p h i t e samples are a l t e r n a t e l y i r r a d i a t e d and p h y s i c a l p r o p e r t i e s measured. 9.1.2.5

9-3

9.2

9.2.1

P W O G W BUDGET AND SCHEDULE

Schedule and kev oronram m i l e s t o n e s

The s c h e d u l e f o r work on g r a p h i t e development i s shown i n Table 9.2.1.1.

The key program m i l e s t o n e s f o r t h i s a c t i v i t y are l i s t e d i n Table 9.2.1.2 and occur a t t h e t i m e s s h o r n i n Table 9.2.P.B.

9.2.2

Budget

The o p e r a t i n g fund requirements f o r t h i s a c t i v i t y are shorn i n Table 9.2.2.1, and t h e c a p i t a l equipment fund requirements are shorn i n T a b l e 9.2.2.2. T h i s i n c l u d e s c a p i t a l equipment funds i n t h e amount of $360,000 i n b o t h plr’ 1980 and PY 1981 f o r c o n s t r u c t i o n of two f a c i l i t i e s f o r i n r e a c t o r i r r a d i a t i o n of l a r g e moderator g r a p h i t e s e c t i o n s .

9.3 9.3.1

MATERIAL BEQUIWEMEmS, BACKGRQUbJIS, AND STATUS OF DEVELOPMENT Material requirements

G r a p h i t e used i n t h e h i g h e s t power d e n s i t y p o r t i o n of t h e c o r e of t h e r e f e r e n c e d e s i g n MSBR w i l l be exposed t o flowing f u e l s a l t a t temperat u r e s up t o 138OQF, w i l l receive f a s t n e u t r o n f l u e n e e s of about 3 x 10” neutrons/cm2, and w i l l be in c o n t a c t with f u e l s a l t c o n t a i n i n g 1 3 5 X e It i s n e c e s s a r y t h a t t h e g r a p h i t e be chemically i n e r t t o t h e s a l t , t h a t i t m a i n t a i n r e a s o n a b l e dimensional s t a b i l i t y and i n t e g r i t y d u r i n g exposure t o t h i s h i g h n e u t r o n f l u e n c e , and t h a t i t have a l o w p e r m e a b i l i t y tu 5Xe under t h e o p e r a t i n g c o n d i t i o n s .

.:.&

S a l t and g r a p h i t e have been shown to b e compatible by nunerous experiments w i t h t h e most convincing proof b e i n g t h e o p e r a t i o n of t h e PISREel G r a p h i t e removed from t h e MSRE a f t e r 5 y e a r s of o p e r a t i o n r e t a i n e d p r e i n s t a l l a t i o n machining marks and documented s u r f a c e i m p e r f e c t i o n s . Salt p e n e t r a t i o n i n t o t h e g r a p h i t e i s prevented by s u r f a c e t e n s i o n f o r c e s i f t h e e n t r a n c e pore diameters t o t h e i n t e r n a l void s t r u c t u r e of t h e g r a p h i t e are sf t h e o r d e r of l wn o r less. Seepage of f u e l s a l t i n t o t h e g r a p h i t e would l e a d t o l o c a l h o t s p o t s which could e a s i l y a t t a i n t e m p e r a t u r e s of l108-120OQC at which t h e g r a p h i t e damage rate i s inc r e a s e d by a f a c t o r of two over that a t 70CBQC.2 F o r t u n a t e l y t h e p o r e s i z e requirement i s e a s i l y w e t by many h i g h - q u a l i t y , fine-grained g r a p h i t e s , and t h i s requirement l e a d s t o no d e s i g n o r material restrictions e

R a d i a t i o n damage i n g r a p h i t e h a s been s t u d i e d e x t e n s i v e l y s i n c e 1945 r e l a t i v e t o t h e Hanford p r o d u c t i o n r e a c t o r s , and more r e c e n t l y under t h e various European and American gas-cooled-reactor programs e I n t h e mid l 9 6 0 ’ s i t became i n c r e a s i n g l y a p p a r e n t t h a t g r a p h i t e h a s a f i n i t e l i f e t i m e i n a f a s t n e u t r o n environment, and t h a t t h e a n i s o t r o p i c a l l y induced

Table 9.2.1.1.

8.2

Graphite

base stock development

8.3

Sealing of graphite reduction

8.4

Pbyslcd

properties

8.5

Evaluation

tests

for permeability

for MSBR graphite

Schedule Ear wark.on

graphite

develapment

9 -5

Table 9 . 2 . 1 . 2 . ~-

..... . . a

*..-

.a&

M i l e s t o n e s f o r g r a p h i t e development ~~

Milestone

Description

Develop damage model f o r g r a p h i t e s i n g l e c r y s t a l s r e l a t i n g damage due t o e l e c t r o n and n e u t r o n i r r a d i a t i o n

Choice of b e s t a v a i l a b l e c o m e r c i a l g r a p h i t e ( r e f e r e n c e ) f o r MSBR u s e

Begirt f a b r i c a t i o n of experimental q u a n t i t i e s of g r a p h i t e s w i t h impraved r e s i s t a n c e t o i r r a d i a t i o n damage

Choice of process f o r r e d u c i n g g r a p h i t e p e r m e a b i l i t y

Measurement of p h y s i c a l property v a r i a t i o n of r e f e r e n c e g r a p h i t e i n i r r a d i a t e d and u n i r r a d i a t e d c o n d i t i o n s

Begin i r r a d i a t i o n of p r o t o t y p e moderator element made o f refererence graphite

Begin i r r a d i a t i o n of sealed (low p e r m e a b i l i t y ) p r s t y p i c moderator element made of r e f e r e n c e g r a p h i t e

Table

9-2.2.1.

(aperating

1975 8.1

Basis

8.2

Graphite

base

Sealing

8.3

graphite

fund requfrements for (costs in 1OOQ &3llars)

1976

graphite

development for

development

Fiscal

yeas 1981

1982

1983

1984

I.985

1977

I.978

1979

1980

100

200

130

150

445

290

304

339

353

350

250

200

150

115

l.l.5

1100 475 -s__l_~~--

500

400

1285

1260

1210

Xl.0

studies stack

graphite

permeabil..i.ty

EdUStiOxl

8.4

Physical

properties

8.5

Evaluation

tests

for

MSBR graphite

Total operating development

funds

for

graphite

---45Q

514

579

643

1210

1986

Table 9.2.2.2.

Capital

equipment (costs

11975 8.1

Basic graphite

8.2

Graphite

8.3

Sealing of graphite reduction

8.4

Physical

I.976

fund requirements in 1000 dollars)

development

Fiscal

year

1980

1981

1982

1983

1984

1985

1977

1978

1979

140

130

I.00

fOQ

100

studies

base stock development

for graphite

for permeability

properties

8.5 Evaluation tests for MSBR graphite Total capital equipment funds for graphite development

370 __

39Q __

145

230

120

630

570

210

130

120

1986

9-8

c r y s t a l l i t e growth r e s u l t i n g from i r r a d i a t i o n damage u l t i m a t e l y c a u s e s gross dimensional changes i n t h e p o l g r c ~ y s t a l l i n eb u l k material. The f l u e n c e t h a t i s d e f i n e d as t h e u s e f u l l i f e t i m e of t h e g r a p h i t e depends somewhat on t h e f a i l u r e c r i t e r i o n employed. The g r a d u a l d e t e r i o r a t i o n of t h e material ~ ~ f i r ls t bed r e f l e c t e d i n i n c r e a s e d xenon a b s o r p t i o n , followed by s a l t p e n e t r a t i o n and e v e n t u a l l y lose of mechanical i n t e g r i t y . The d e f i n i t i o n p r e s e n t l y USed, t h a t t h e m t e r i a l Undergo BO S i g l i f i C a n t radiation-induced b u l k expansion, i s c e r t a i n l y a c o n s e r v a t i v e assumpt i o n . If t h e g r a p h i t e l i f e t i m e were t o b e e q u a l t o t h e d e s i g n pHant l i f e of t h e r e f e r e n c e d e s i ft MSBW (which has a peak power d e n s i t y of 100 watts/cm3), t h e g r a p h i t e w o u l d e x p e r i e n c e a a m a g e f l u e n e e of about 3 x PO23 n e ~ t r o n s - c m -which ~~ i s about ten t i m e s what the b e s t material w i l l withstand. he approach f o r excluding 13%e from the i n t e r i o r of t h e g r a p h i t e with i t s a t t e n d a n t improvement i n b r e e d i n g r a t i o i s d i s c u s s e d i n d e t a i l i n S e c t i o n 8. T r a n s l a t e d t o a materials requirement, however, xenon exc l u s i o n i m p l i e s e f f e c t i v e gas p e ~ m e a b i l i t iof ~ ~10-8 em2/sec helium STP OK lower, which r e q u i r e s maximum p o r e e n t r a n c e d i a m e t e r s of 8.01 ym OK less. Such p o r e s i z e s are n o t a t t a i n a b l e i n t h e o r d i n a r y f a b r i c a t i o n of b u l k graphite. The requirement can be e a s i l y met by p y r o l y t i c d e p o s i t i o n of carbon o n t o a b u l k g r a p h i t e , a l t h o u g h i t h a s n o t y e t been demonstrated that such c o a t i n g s have a d e q u a t e i r r a d i a t i o n s t a b i l i t y .

The e x i s t e n c e of a g r a p h i t e lifetime which i s lower than. t h e d e s i r e d p l a n t l i f e f o r c e s t h e r e a c t o r d e s i g n e r to a c c e p t Pow power d e n s i t i e s O K t o make p r o v i s i o n s f o r p e ~ f o d i s~ e ~ ~ t of v athe l g r a p h i t e . The l a t t e r approach has been adopted f o r the r e f e r e n c e d e s i g n MSBR as d i s c u s s e d in S e c t i o n 8. The requirement for s a l t e ~ c l u s f o n ,and t h e r e b y a f i n e g r a i n e d g r a p h i t e , also d e t e r m i n e s t h a t the geometric c r o s s s e c t i o n of the graphite prisms be k e p t l o w . T h i s i s n e c e s s i t a t e d by t h e inability to c o n t r c ~microstructure t o t h e desired d e g r e e i n forming ana h e a t t r e a t i n g g r a p h i t e members having l a ~ g ec r o s s s e c t i o n s . Small cross s e c t i o n s a l s o have t h e advantage sf minimizing thermal g r a d i e n t s $w the g r a p h i t e dUk-i92 r e a c t o r o p e r a t i o n and t h u s reducing t h e r a t e a t which r a d i a t i o n dareage o c c u r s .

I n t h e several MSB d e s i g n s t u d i e s carried out t o d a t e , the problems of graphite removal and prism geometry have been approached i n s e v e r a l d i f f e r e n t ways 4-6 Mechanical a n a l y s e s 7 have i n d i c a t e d t h e r e are no s i g n i f i c a n t thermal OK r a d i a t i o n - i n d u c e d stresses i n graphite i n any of- t h e d e s i g n s . e

9.3 2

Background

9.3.2.1

General

G r a p h i t e h a s been employed as a nuclear material f o r as l o n g as t h e r e have been reactors. It f o m e d t h e m s d e r a t s r i n t h e Stagg F i e l d experiment and i n the p r o t o t y p e Oak Ridge Graphite Reactor. The f i r s t e x t e n s i v e

.. e.,&

e....

9-9

e x p e r i e n c e w i t h g r a p h i t e w a s a c q u i r e d in t h e Nanford p r o d u c t i o n r e a c t o r s and somewhat h a t e r i n t h e B r i t i s h gas-cooled r e a c t o r s , a l b e i t a t lower t e m p e r a t u r e s and f l u e n c e s t h a n apply t o MSR's. More r e c e n t l y t h e DrrtgOn Reactor i n i t i a t e d the Use Of g r a p h i t e a t temperatures i n t h e 1800°C range9 followed s h o r t l y by the Peach Bottom Reactor in the U.S. and t h e AVR Reactor i n Germany. C u r r e n t l y , gasc ~ o H e dr e a c t o r s are being designed or o p e r a t e d which have g r a p h i t e t e m p e r a t u r e s i n t h e h280-130O8@ t e m p e r a t u r e range. Much of t h e e x p e r i e n c e and d a t a o b t a i n e d in the g a ~ - ~ o ~ $ er edai c t o r prog a m i s d i r e c t l y a p p l i c a b l e to MSR'S. In p a r t i s u h ~ ,d a t a o b t a i n e d a t Hanford i n t h e mid-1960's spanning t h e t e m p e r a t u r e r a n g e 308-1188'C f i r s t i n d i c a t e d t h e f i n i t e l i f e t i m e of g r a p h i t e r e s u l t i n g from neutroninduced damage, i . e . , i t s e v e n t u a l dimensional expansion and l o s s of mechanical i n t e g r i t y .

. d

In l a t e 1968, a program w a s i n i t i a t e d at ORNE t o e v a l u a t e g r a p h i t e s f o r m o l t e n - s a l t b r e e d e r r e a c t o r a p p l i c a t i o n , and more s p e c i f i c a l l y , t o d e t e r m i n e what limitations b p r ~ ~ eg rda p h i t e d g h t 5mpose on r e a c t o r design. A development program was proposed8 t o demonstrate feasibility of improving g r a p h i t e by 1975, and t o b r i n g such ~ I T L ~ P O V ~ Rt oI ~comB ~ ~ ~ merical a p p l i c a t i o n by 1980. However, t h e development program has n o t been f u l l y implemented clue t o funding l i m i t a t i o n s . N e v e r t h e l e s s , cons i d e r a b l e p r o g r e s s has been achieved toward demonstrating t h e c a p a b i l i t y of e x i s t i n g materials t o meet MSBR requirements and t o d e l i n e a t e areas f o r f u t u r e development. 9.3.2.2

Basis g r a p h i t e s t u d i e s

Techniques were developed a t O W L f o r i r r a d i a t i n g g r a p h i t e w i t h e l e c t ~ o n s in an e k e e t r s n d e r o s c o p e and s i m u l t a n e o u s l y observing t h e strrecturalb changes as t h e y occurred. Techniques were also developed f o r c o n t r o l l i n g t h e specimen t e m p e r a t u r e , so t h a t a n n e a l i n g and c l u s t e r i n g of d e f e c t s could be observed. The s t u d i e s c a r r i e d o u t showed t h a t t h e r e p o r t e d value f o r t h e displacement energy f o r C ~ K ~ C XaI t m ~in a g r a p h i t e l a t t i c e w a s l i k e l y i n e r r o r . T h i s p h y s i c s parameter is basic i n p r e d i c t i n g t h e number of atomic d i s p l a e e m e n t s caused by a primary knock-on.

9.3.2.3

I r r a d i a t i o n damage s t u d i e s

The b a s i c i r r a d i a t i o n damage phenomena in g r a p h i t e arise from t h e extreme a n i s o t r o p y of t h e c r y s t a l . The carbon atoms are a r r a y e d i n tightly bound hexagons i n p l a n a r a r r a y . The p l a n e s are w e l l - s e p a r a t e d and weakly ~ by n e u t r o n bombardment move f r e e l y coupled. I n t e r ~ t i t i a lproduced betweem p l a n e s and r e i n t e g r a t e as new planes. Vacaneies l e f t behind are c o l l a p s e d . One is thus left with the p i c t u r e sf a s i n g l e c r y s t a l expanding i n d e f i n i t e l y i n one d i r e c t i o n and c o n t r a c t i n g i n t h e o t h e r two w i t h l i t t l e change i n net volume. Thus, i n a p o l y c r y s t a l l i n e r a t e r i a l ,

each c r y s t a l l i t e is e x p a n d b g and ~ o n t ~ a c t i ni n g varying d i r e c t i o n s , and i t i s h a r d l y s u r p r i s i n g t h a t t h e material e v e n t u a l l y d e t e r i o r a t e s . What i s remarkable i s i t s a b i l i t y t o w i t h s t a n d t h e s e changes. P a r t i a l l y o r i e n t e d p y r o 8 y t i c graphites i r r a d i a t e d i n H F I R t o fluences of 3 x neutaons/crn2 a t PER temperatures expanded 500% i n t h e p r e f e r r e d c - a x i s d i r e c t i o n without l o s i n g mechanical i n t e g r i t y !

..... <.x<.

During t h e perfod 1963-1971, over e i g h t y d i f f e r e n t e x p e r i m e n t a l and comercially a v a i l a b l e g r a p h i t e s were i r r a d i a t e d i n HFIR t o e s t a b l i s h 9 AII u n d e r s t a n d i n g 0% the m i c r o s t r u c t u r a l t h e i r d ~ m e n s i a n abehavior ~ p r o p e r t i e s of graphite t h a t a r e of s i g n i f i c a n c e t o r a d i a t i o n damage has g r a d u a l l y e ~ ~ p e ~ g eand d , can b e summarized as fslliows:

In t h e 600 to 880'C temperature range of i n t e r e s t to m o l t e n - s a l t breeder r e a c t o r s , b u l k g ~ a p h i t ecan ~ b e classified i n t o t h r e e behavior mdes depending on t h e i r f a b r i c a t i o n h i s t o r y , namely c o n v e n t i o n a l materials, black-based materials, and ~ a a n o l i t h i ~ materials 8 Conventional materials i n c l u d e a l a =normal e o ~ ~ ~ ~ c i a l g r a p h i t e s that are f a m e d from calcimed coke or g r a p h i t e fillers, b i n d e r e d w i t h t h e m o s e t t i n o r t h e r m o p l a s t i c materials, and subs e q u e n t l y h e a t t r e a t e d . These materials m a y be isotropic o r a n i s o t r o p i c , b u t show an immediate volume c o n t r a c t i o n d u r i n g i r r a d i a t i o n f ~ l l ~ w ebyd r a p i d and c a t a s t r o p h i c exp8nsion. T h e i r l i f e t i m e s Z L K ~i n the range from 1 to 2.5 x H W ~ P O ~ ~ / C E ~ ~ (E 50 keV). The rate of volume expansion i s characteristically p a r a b o l i c w i t h i n c r e a s i n g fluence. e

The secsncl c l a s s , black-based g r a p h i t e s , employs carbon b l a c k s as f i l l e r s . The i n d i v i d u a l b l a c k s have a roughly s p h e r i c a l c r y s t a l l i t e shape which i s c a p a b l e of w i t h s t a n d i n g h i g h t a n g e n t i a l s t r a i n . Depending on h e a t t r e a t m e n t t e m p e r a t u r e , these materials w i l l first c o n t r a c t r a p i d l y and then expand linearly w i t h f u r t h e r i r r a d i a t i o n , The d i f f e r e n c e i n the expansion behavior frs~mt h a t of the more c o n v e n t i o n a l g r a p h i t e s i s t ~ ~ ~ t a t i v e xl pyl a i n e d by the a b i l i t y of t h e b l a c k p a r t i c l e s t o withstand s t r a i n . The t h i r d class, and t h e one of i n t e r e s t f o r MSBR applications, is the m o n o l i t h i c ~ t - ~ t t ~ t which ~ k d s appear t o b e b i n d e r l e s s , o r for which the f i l l e r material i s chemically active and reacts w i t h the b i n d e r . The r e s u l t i s a n extremely homogeneous s t r u c t u r e t h a t i s u s u a l l y unmarked by microstructures. Under i r r a d i a t k m , these materials undergo a prolonged s t a b l e i n d u c t i o n period before b e g i n n i n g a p a r a b o l i c expansion p e r i o d . The lifetimes of gra h i t e s of t h i s class t e s t e d t o d a t e l i e i n t h e range of 2 t o 3 x 10 neutrsns/erra2 (E > 50 keV). The b e s t materials of t h i s type are i n v a r i a b l y isotropic, and t h e i r i n d u c t i o n p e r i o d i s a t t r i b u t e d t o their h i g h ~ d ~ ~ o s t ~ and e ~ a~b g il% t ht y t o flow p l a s t i c a l l y to relieve strain. The p a r a b o l i c expansion of t h e s e materials and of t h e c o n v e n t i o n a l graphites can be related t o void g e ~ ~ ~ aast i ~ n the s t r u c t u r e f i n a l l y f r a c t u r e s a t the crystallite l e v e l . 10

$... 2.2

9-11

I n summary, t h e g e n e r a l n a t u r e of damage i n p o l y c r y s t a l l i n e g r a p h i t e i s understood, and i t s r e l a t i o n s h i p t o m i c r o s t r u c t u r e i s a t least q u a l i t a t i v e l y demonstrated. 9.3.2.4

Fabrication studies

Based on t h e HFIR i r r a d i a t i o n d a t a , a program w a s i n i t i a t e d i n 1390 t o exp1~b-et h e f a b r i c a t i o n of m o n o l i t h i c graphites w i t h the s p e c i f i c a i m of improving i r r a d i a t i o n damage r e s i s t a n c e . S m a l l samples up t o t h r e e i n c h e s i n d i a m e t e r were used, and t h e r a w materials were l i m i t e d t o t h r e e cokes and several t h e r m o s e t t i n g o r t h e r m o p l a s t i c b i n d e r s . The e s s e n c e of t h e i m p ~ o v e df a b r i c a t i o n p r o c e s s i s i n t h e u s e of cokes in t h e i r u n c a l c i n e d c o n d i t i o n i n which they a r e s t i l l chemically a c t i v e . The chemical i n t e r a c t i o n between coke and b i n d e r and t h e similar s h r i n k a g e rates of t h e two d u r i n g c a r b o n i z a t i o n r e s u l t in the d e s i r e d monolithic s t r u c t u r e . 1 These materials have undergone i r r a d i a t i o n t e s t i n g t o fluernce levels as h i g h as 1.5 x neutrons/cm2. To t h i s l e v e l , t h e materials have been s t a b l e , and t h u s c o n f i m our c o n c l u s i o n s from hypotheses based on damage models a

9.3.2.5

S t r e s s e s and c r e e p

The g r a p h i t e c o r e prisms i n a n MSBR are ~ e q u i r e df o r no s t r u c t u r a l purpose e x c e p t to d e l i n e a t e t h e s a l t flow p a t h s and t o s u p p o r t t h e i r ow11 weight when t h e r e a c t o r primary c i r c u i t i s d r a i n e d . However, t h e q u e s t i o n remains as t o t h e magnitude of t h e r m a l o r radiation-induced stresses. These have been c a l c u l a t e d w i t h t h e r e f e r e n c e d e s i g n MSBR f o r c o n v e n t i o n a l g r a p h i t e a t t h e w o r s t position i n t h e c o r e , i e e e ,on t h e c u r e c e n t e r l i n e just above t h e midplane.6 The c a l c u l a t e d stresses are q u i t e low and can b e n e g l e c t e d . It i s thus concluded t h a t t h e m a l and radiation-induced stresses are no problem even f o r t h e r e l a t i v e l y poorI.y behaved c o n v e n t i o n a l g r a p h i t e s f o r f l u e n c e levels up t o t h e d e f i n e d g r a p h i t e l i f e t i m e ( t h e t i m e a t which t h e f l u e n c e l e v e l r e a c h e s t h a t r e q u i r e d t o c a u s e expansion of t h e b u l k g r a p h i t e beyond i t s i n i t i a l volume).

9.3.2.6

S e a l i n g t o p r e v e n t xenon a b s o r p t i o n

The approach used to e f f e c t i v e l y seal g r a p h i t e w i t h r e s p e c t t o xenon permeation t a k e s t h r e e forms: d i r e c t impregnation by hydrocarbons followed by h e a t t r e a t m e n t t o leave a carbon r e l i c i n t h e p o r e , s u r f a c e t r e a t m e n t t o s e a l t h e p o r e s a t o r n e a r t h e s u r f a c e , o r impregnation w i t h a l i q u i d o r s o l i d salt t o f i l l t h e p o r e s .

9-12

S u f f i c i e n t e x p e r i e n c e e x i s t s i n t h e g r a p h i t e i n d u s t r y to i n d i c a t e t h e limitations of d i r e c t carbsnacesus h p r e a t i o n . The decomposing hydrocarbon g e n e r a t e s gaseous p ~ o d i u c t swhich must escape t o t h e surface o r produce r u p t u r e i n t h e bulk g r a p h i t e . The lowest practical xenon p e r m ~ & i l i t y which can be achteved by t h i s approach i s of the order of 10-6 cm2/sec, which is a f a c t o r POO I . ~ K er than r e q u i r e d for a d e q u a t e l y excluding xenon from MSBR graphite. T h i s approach has t h e r e f o r e not been explored f u r t h e r in t h e MSR I ) K O ~ K ~ .

coating of was newt i n v e s t i g a t e d , u t i l i z i n g base gk-apkites and coating s t r u c t u r e s knsm t o b e d i m e n s i o n a l l y s t a b l e under i ~ r a d i a t i o n . he initial i r r a d i a t i o n z. o s u l t s 9 indicated l i m i t e d s u c c e s s ; a f e w samples retained their i n i t i a l ISJ p e r m e a b i l i t i e s t o t h e maximum fluence employed, about 2 x neu%rons/cm2, b u t t h e majority had p e ~ ~ ~ a b i l i twhich ies w e r e no better than that of the u n i ~ l p r e g n a t e dmaterials. It is now h o r n t h a t t h e c o a t i n g s were flawed before irradiation, and a r e v i s e d coating process was developed 1

*The perneabilities as used here are d e r i v e d from g a s flow measurements h both t h e sealed r e g i o n and the remaining u n a f f e c t e d substrate g r a p h i t e . The actual pelpaneabilities a t the sealed surface lag re^ a r e probably a f a c t o r of PO0 lower.

..~

9-13

One of the recent major diagnostic advances has been development of scanning electron microscopes that are capable of examining graphite surfaces. The flawed samples alluded to above appeared perfectly S Q U ~ ~ under even t h e l i g h t microscope. However, ~ n d e rthe scanning electron microscope, various types ~f flaws were readily apparent as well. as changes in microstructure. The defects w e r e found to be due to faulty gas circulation, soot incPusions, and the presence of sharp corners on the graphite cylinders being coated. It is believed that these f a c t o r s have been eliminated in the current coating p r o c e s s , however, this has not been verified by irradiation of test samples. 9.3.2.7

Thermal conductivity measurements

It w a s anticipated initially that changes in therml conductivity due to radiation damage under MSR conditions would be slight. Recent data, ~ Q W ~ V ~ Xhave = , implied t h i s m y not b e the case,' and experirtlents have been initiated in HFIR to determine the extent of t h e degradation in conductivity 9 Preliminary results i m p l y the conductivity may decrease to about one third of the initial value. e

g The thermal ~ o n d ~ c t i ~ istf ygraphite is important in c ~ n t r ~ l l i nthe internal graphite temperatures, and thereby the rate of irradiation damage accumulation. The average dimensional change observed for a graphite p r i s m undergoing radiation damage is essentially equal to t h a t which would b e observed if the p r i s m were at its mean temperature throughout 7 since damage r a t e increases w i t h increasing tenperatrare it is desirable to minimize internal temperature gradients. e

9.3,2.8

Manufacturing capability and c o s t s

An extensive survey ~f various comercia1 g r a p h i t e s identified one graphite that is acceptable for the MSBR reference design, a second graphite that is acceptable but available only in limited sizes, and two other graphites which are potentially acceptable. FsrtuFtously, these graphites involve four separate vendors. Great Lakes Carbon Corporation's grade H-364 is available in t h e d e s i r e d g e ~ ~ ~ e tand ~ i epossesses s a lifetime (before significant expansion occurs) of t h e order of 2.5 x neutrons/cm2 (E 50 K ~ V )at 715"~. nis i s 17% lees than the graphit{? life specified in the reference design brat is close enough to b e cornpensatable by allowing more expansion, reducing the mxirraum power density, or replacing the g r a p h i t e somewhat earlier. POCO grade AXF is the best commercial material which has been encountered anst has a lifetime sf the order sf 3 to 3.5 x lo2', but t h i s material is currently available only in short lengths. Material s u b d t t e d by Airco Spear and Pure Carbon Companies may a l s o fall f n t s the class of these graphites but to date these materials have been irradiated to a fluence of only 1.5 x Their behavior appears to be simflar t o that of t h e b e s t of the monolithic graaes.

9-14

It has not been p o s s i b l e t o o b t a i n f i r m p r i c e estimates on t h e f o u r raphite which are p o t e n t i a l l y a c c e p t a b l e f o r t h e reference d e s i g n MSBR, b u t t h e y appear to f a l l i n t o t h e range of $5 t o $10 p e r pound of f i n i s h e d g r a p h i t e , even on a f i r s t - o r d e r b a s i s . Prices of $5 p e r pound O K Isweb- appear t o b e p r o b a b l e if t h e market becomes s u f f i c i e n t l y l a r g e to permit the g r a p h i t e t o b e handled as a s t o c k i t e m . With r e g a r d t o p y r o l y t i c coatin o r s e a l i n g , t h e r e i s a n e x i s t i n g ind u s t r y a l r e a d y p ~ ~ d ~ c isuch n g c o a t i n g s p r i m a r i l y for a e r o s p a c e appbic a t i o n s . However, t h e most i r r a d i a t i o n - r e s i s t a n t t y p e of c o a t i n g (LTI, OK low temperature isotropic) i s u s i n g process parameters q u i t e d i f f e r e n t . from t h o s e i n u s e by t h e e x i s t i n g i n d u s t r i a l firm. E s t i m a t i n g the c o s t of c o a t i n g o p e r a t i o n is d i f f i c u % t s i n c e a p r o c e s s has n o t been aeQelsped, b u t i t is b e l i e v e d t h a t $25 to $30 p e r Eb of f i n i s h e d g r a p h i t e f o r t h e proposed S l a b geOmet%y ShOU$d CBVier the Coating o p e r a t i o n duafhg i t s early development. Eventua%ly, c o a t i n g c o s t s should drop to $5 to $7 p e r %b for p.k-oduction q u a n t i t i e s .

9.3.3

S t a t u s of development

A number of u n c e r t a i n t i e s remain, none of which p a r t i c u l a r l y a f f e c t t h e v i a b i l i t y of the m o l t e n - s a l t b r e e d e r concept. These u n c e r t a h t i e s may e f f e c t f u r t h e r compromises i n d e s i g n and perhaps economies, b u t i n no Case are they V i t a l to the t e c h n i c a l o r economic u s e of g r a p h i t e i n t h e r e a c t o r . These u n c e r t a i n t i e s appear t o b e r e s o l v a b l e by f u r t h e r work On graphite development,

9.3.3.1

I r r a d i a t i o n damage and g r a p h i t e f a b r i c a t i o n

The p o t e n t i a l f o r developing improved g r a p k i t e s t h a t can b e employed by MSBR's a t fluence l e v e l s beyond 3 . 5 x XI2' i s h i g h . A q u e s t i o n remains concerning t h e d e g r e e of hprovement t o b e a n t i c i p a t e d . Confidence that a t least i n c r e m e n t a l improvements can b e made has i n c r e a s e d s i g n i f i c a n t l y w i t h improved u n d e r s t a n d i n g of t h e r e l a t i o n s h i p s between m i c r o - s t r u c t u r e and i r r a d i a t i o n damage. The a v a i l a b i l i t y of HFIR (or fast r e a c t o r s i n t h e f u t u r e ) in which fluences can b e a t t a i n e d i n less t h a n a year that are e q u i v a l e n t to t h o s e f o r an MSBW after several y e a r s e n a b l e s a g r a p h i t e development program t o proceed a t a r e a s o n a b l e rate.

The g r a p h i t e f a b r i c a t i o n process which i s c u r r e n t l y b e i n g s t u d i e d a t OWL h a s been e x p l o r e d only b r i e f l y . Areas a w a i t i n g examination where f u r t h e r p r o g r e s s can be a n t i c i p a t e d i n v o l v e t h e use of b l a c k s i n processes ana%s g s u s t o t h e green-coke K B U ~ ~and , t h e u s e sf h i g h - p r e s s u r e p r o c e ~ s i n g for b o t h r a w materials and c a r b o n i z a t i o n . To date very l i t t l e e f f o r t has been expended by i n d u s t r y and o t h e r government l a b o r a t o r i e s toward i n c r e a s i n g t h e l i f e o r s t a b i l i t y sf g r a p h i t e , and the development sf new processes and d i a g n o s t i c techniques suggest t h a t much more r a p i d p r o g r e s s can b e made. The a l t e r n a t e f a b r i c a t i o n techniques and t h e i r r e l e v a n c e t o damage r e s i s t a n c e can be a t least i n d i c a t e d w i t h i n two o r t h r e e y e a r s

k...L

9-15 a f t e r work i s i n i t i a t e d . The f a c t t h a t p y r o l y t i c materials have s u r v i v e d t o f l u e n c e s g r e a t e r t h a n 1.5 x BO" neutrons/cm2 implsles t h a t l i f e t i m e s of t h e o r d e r o f 5 x 10" n e u t r o n s i c & a t 700°C s h o u l d be a t t a i n a b l e .

The a b i l i t y to exclude xenon from g r a p h i t e i n the MSBR core by means sf p y r o l y t i c g r a p h i t e impregnation o r c o a t i n g h a s n o t been demonstrated. A l t e r n a t i v e s e a l i n g techniques e x i s t b u t c u r r e n t l y remain unexplored. Both c o a t i n g s and s u b s t r a t e s have been shown s e p a r a t e l y t o s u r v i v e t o fluelace v a l u e s g r e a t e r t h a n 3 x ~ e n c e ,this i s s t r o n g r e a s o n t o b e l i e v e t h a t a c o a t i n g w i l l be s a t i s f a c t o r y f o r the MSBR. However, i n t h e g a s - ~ o o l e d react.or program, where c o a t i n g s have been shown t o s u r v i v e e q u i v a l e n t f l ~ e n c e s ,it has been found necessa93p to decouple t h e s u b s t r a t e and c o a t i n g . Both Pow d e n s i t y p y r o l y t i c and s i l i c o n c a r b i d e i n t e r c o a t i n g s have been employed, and analogous techniques could p o s s i b l y b e u t i l i z e d h e r e . I f such techniques are r e q u i r e d , a p e r i o d of two t o I n any event, f u r t h r e e y e a r s would b e needed fop t h e i r development. ther work t o s c a l e u p s e a l i n g methods and p r e p a r e f o r t r a n s i t i o n t o commercial s u p p l i e r s w i l l b e r e q u i r e d .

Two a l t e r n a t e s e a l i n g t e c h n i q u e s i n v o l v e f i l l i n g t h e p o r o s i t y i n t h e g r a p h i t e w i t h l i q u i d o r s o l i d s a l t . U n c e r t a i n t y remains as t o whether t h e d i f f u s t v i t y of xenon in t h e l i q u i d o r s o l i d i s s u f f i c i e n t l y l o w and whether u r a n i n t r a n s f e r s r a p i d l y between t h e f u @ l salt and t h e impregn a n t s a l t . The p o t e n t i a l of t h i s approach could b e determined i n about Q I I ~y e a r . Underlying a l l of t h e Work on g r a p h i t e s e a l i n g are q u e s t i o n s related t o t h e rate a t which xenon w i l l b e t r a n s p o r t e d i n t o t h e g r a p h i t e quite independent of i t s p e r m e a b i l i t y . For example, t h e c u r r e n t u n c e r t a i n t y i n t h e m a s s t r a n s f e r c o e f f i c i e n t between t h e f u e l s a l t and helium b u b b l e s a l l o w s t h e p o s s i b i l i t y t h a t unsealed g r a p h i t e nay b e a c c e p t a b l e . Information OH t h i s and o t h e r f a c t o r s a f f e c t i n g xenon removal w i l l b e s t u d i e d i n an e x i s t i n g f a c i l i t y (Gas S y s t e m Technology F a c i l i t y ) t h a t is f u l l scale f o r a 15Q-MW(t) MSR (see S e c t i o n 10).

9.3.3.3

Thermal c o n d u c t i v i t y

The d e g r a d a t i o n of t h e m a l c o n d u c t i v i t y w i t h i n c r e a s i n g fluence l e v e l remains t o b e e s t a b l i s h e d , and t h i s leaves u n c e r t a i n the maximum crosss e c t i o n a l area of g r a p h i t e prisms t h a t will be a c c e p t a b l e i n an MSBR. Although r e p r e s e n t i n g o n l y a q u e s t i o n sf d e s i g n , i t must b e answered.

....

x.p>

... ....

.'...y. ...

9-16

Present knowledge on c r e e p i n g r a p h i t e l e a d s t o an a n a l y s i s I n d i c a t i n g that only t r i v i a l s t ~ e s s e sare developed i n the graphite. Recent unpublished r e s u l t s o b t a i n e d at H a n f ~ ~may d indicate t h a t t h e a b i l i t y of g r a p h i t e t o creep deteriorates a t h i g h fluences. I f so, the problem can l i k e l y be a v ~ i d e dby changes i n d e s i g n , b u t the situation i s u n c e r t a i n and r e q u i r e s a d d i t i o n a l s t u d y T .

9.3.3.5

General e v a l u a t i o n

Sufficient data on t h e therm1 and mechanical properties ~f gragkites of t h e t y p e r e q u i r e d f o r t h e MSBR have not been o b t a i n e d in the uni r r a d i a t e d and i r r a d i a t e d c o n d i t i o n s . Enough is k n o m t o b e c e r t a i n t h a t mechanical p r s p e r t i e s do not a f f e c t the e x a c t shapes of g r a p h i t e p e r d t t e d nor t h e EXIS IS by which t h e g r a p h i t e is s u p p o r t e d , but addit i o n a l d a t a must b e s e c u r e d f o r d e % i

9.4

TASK GROUP 8.1

These stradFes w i l l b e concerned with determining b a s i c r a d i a t i o n danage m e e h a n i s ~i~n g r a p h i t e . S i n g l e c r y s t a l s will be used to determine the t y p e s and numbers of d e f e c t s produced by i r r a d i a t i o n . Annealing k i n e t i c s w i l l b e observed by transmission e l e c t r o r n i c r ~ ~ c o p y .

9.4.1

Objective

The o b j e c t i v e of t h i s t a s k w i l l be t~ deeersaine t h e b a s i c mechanism of radiation damage and annealin f o r graphite.

9-17 9.4.2

Schedule

The s c h e d u l e f o r W Q K ~i n t h i s task group i s shown in Table 9 . 4 . 2 .

9.4.3

Funding

Operating fund requirements f o this ~ t a s k group are shown in Table 9 . 4 . 3 . 1 , and capital equipment fund requirements are shorn in Table 9 . 4 . 3 . 2 .

9.4.4

Facilities

High p u r i t y s i n g l e c r y s t a l s s f graphite w i l l b e i r r a d i a t e d with e l e c t r o n s in a n e l e c t r ~ nmicroscope. The number and morphology of t h e defects will b e determined a t v a r i o u s t ~ ~ p e ~ a t u rSome ~ ~ iof. the erdamagedft samples w i l l be h e l d a t t e m p e r a t u r e and t h e annealing of d e f e c t s observed. This work should result i n an a c c u r a t e v a % w for t h e energy r e q u i r e d to d i s p l a c e a carbon atom from the graphite l a t t i c e . Quantitative information ~ h ~ u l be c i o b t a i n e d about i r r a d i a t i o n damage and annealing in g r a p h i t e s i n g l e crystals ,..A

9.4.6

Task 8.1.2

I r r a d i a t i o n damage and annealing in p o l y c r y s t a l l i n e

graphite

me pkesenee of grain b o u n d a r k s in g r a p h i t e C C l m p l i C a t e S % r r a d i a t i O n

.:.a

damage mechanf5m o v e r those o c c u r r i n g i n single c r y s t a l s . The boundary serves as b o t h source and sink for d e f e c t s and as a surface t o s t a b l i z e p l a n a r d e f e c t s . It is a n t i c i p a t e d t h a t grafn s i z e and the a n g u l a r &is=match between a d j a c e n t grains w i l l b e important v a r i a b l e s and a systema t i c s t u d y will be made of t h e i r i n f l u e n c e . 9.5

TASK GROUP 8.2

G W H I T E BASE STOCK DEVELOPMENT

Work in t h i s task group w i l l involve a s t u d y of the b a s i c raw materials a d f a b r i e a t i Q n prQc%SSeS US&d graphite. CS exper8mental g ~ a p h i t e sw i l l b e c h a r a c t e r i z e d , i r r a d i a t e d , and dimensional

...

:;&+j

....

Table

8.1.1

8.1.2

9.4.2.

Schedule

fdar work

Task

Irradiation graphite

damage and single crystals

annealing

Ir~adiatfon

damage

annealing

paly@rystalline

and

graphite

Group

8.1

Basic

graphite

studies

Table

9.4.3.1.

Operating

cost

requirements (costs in

for Task Group 1008 dollars)

1976 8.1.1

8.1.2

Total

Irradiation damage single crystals

and annealing

Irradiation crystalline

and annealing

operating

damage graphite funds

for

Task Group

8.1

-Basic

graphite

studies

Fiscal

year

1977

1978

1979

19 80

BOO

25 50

50 100

100 200

graphite

paly-

1981

Table

Capital

9.4.3.2.

equipment fund requirements (costs in IQQQ doJLlars)

for

Task

Fiscal 1976 8.1.1

X3.1.2

Total

Irradiation damage single crystals

and

Irradiation crystalline

and annealing

capital

damage graphite equipw2nt

funds

annealing

for

Task

Group

8 .% -

year

1977

I.978

50 75

1979

graphite

poly-

8.1

25 25

1980

9-21 and physical p r o p e r t y changes measured. The g o a l w i l l b e t o c o r r e l a t e s t a r t i n g material and f a b r i c a t i o n v a r i a b l e s w i t h dimensional s t a b i l i t y during i r r a d i a t i o n .

9 5 1 Obj e c t i v e e

The o b j e c t i v e sf t h i s t a s k group i s t o i d e n t i f y and c h a r a c t e r i z e t h e most d e s i r a b l e g r a p h i t e s f o r MSBR u s e .

9.5.2

Schedule

The s c h e d u l e f o r work i n t h i s task. group i s shown in Table 9.5.2.

9.5.3

Funding

Operating fund requirements f o r t h i s task. group are s h a m i n Table 9.5.3.1, and c a p i t a l equipment fund requirements are shown i n Table 9 . 5 . 3 . 2 .

9.5.4

Facilities

This t a s k group w i l l make use of several l a b o r a t o r i e s i n BPdg. 4568 and of t h e g r a p h i t e f a b r i c a t i o n equipment l o c a t e d i n Bldg. 9202, Y-12. Experiments w i l l b e i r r a d i a t e d i n HPIR and disassembled i n t h e h o t c e l l s i n Bldg. 3Q26D.

Numerous grades of g r a p h i t e are m d e c o m e r i c a l l y i n t h e US and f o r e i g n c o u n t r i e s . Research q u a n t i t i e s of t h e more desirable materials w f l l b e procured and e v a l u a t e d . E v a l u a t i o n w i l l include measuring several p h y s i c a l properties such as p o r e s i z e spectrum, gas p e r m e a b i l i t y , cryst a l l i n e a n i s s t r o p y , d e n s i t y , e l e c t r i c a l c o n d u c t i v i t y , and c o e f f i c i e n t of thermal expansion in t h e u n i r r a d i a t e d c o n d i t i o n . The most a t t r a c t i v e materials w i l l b e i r r a d f a t e d and t h e dimensional changes observed as a function O f fluence. 9.5.5.1

Subtask 8.2.1.1

Vendor l i a i s o n and pretsurement

The manufacture of g r a p h i t e is a h i g h l y s p e c i a l f z e d and p r o p r 9 e t a r y o p e r a t i o n . Continued l i a i s o n w i t h t h e contnaerical vendors i s r e q u i r e d t o keep them knowledgeable and i n t e r e s t e d i n t h e MSR Program needs. In some cases, g r a p h i t e s of p o t e n t i a l u s e are c u r r e n t l y i n p r o d u c t i o n . In o t h e r cases vendors can modify an existing fornulation o r f a b r i c a t i o n p r o c e s s to o b t a i n a g r a p h i t e u s e f u l f o r M%BR a p p l i c a t i o n s . Q u i t e o f t e n a c o m e r i c a l g r a p h i t e w i l l b e of i n t e r e s t p r i m r i I y because of t h e raw ...

... .....

;:ye

Table 9.5.2.

ScbecMe for work in Task Group 8.2 -- Graphite

base stock development Fiscal. year

--I-1982

8.2.1

8.2.2

lt~3,3.uatian of comercial graphites 8.2.1.1 Vendor liason and procurement 8.2.1.2 Characterization of commercial graphites 8.2.1.3 Irradiation of camnercial graphites Development and evaluation of experimental graphites 8.2.2.1 Cbolce af raw materials 8.2.2.2 Study of fabrication processes 8.2.2.3 Characterization of experimental graphites 8.2.2.4 IrracHation of experimental graphites

_-.-

198%

Table 9.5.3.1.

Operating

fuud requirements

for Task Group 8.2 - Graphite

base stock development

Fiscal

8.2.1

Evaluation of commercial graphites 8.2.1.1 Vendor liason and procurement 8.2.1.2 Characterization of commercial graphites 8.2.1.3 IrradiatAon of commercial graphites Subtotal

g.2.2

Total

8.2.1

1976

1977

1978

1979

1980

1981

1982

1983

19 84

65 65 ----___130 130

7.5

I.50

150

155

5Q PO0

50 100

50 1QQ

Development and evaluation of experimental graphites &2.2.1 Choice of raw materials 8.2.2.2 Study of fabricatian processes 8.2.2.3 Characterization of experimental graphites 8.2.2.4 Irradiation of experimental graphites Subtotal

8.2.2

operating

funds for Task Group 8.2

year

-VP-__130 130

150

15Q

1985

100 --

100

290

29Q

290

445

1986

Table 9.5.3.2.

Capitals equipment

fund reqdxements for Task Group 8.2 - Graphite (costs in lBOQ dollars)

1975 8.2.1

__ Evaluation of couQnersial graphites 8.2.1.1 Vendor liasan and procurement 8.2.1.2 Characterization af eommrcial graphites Subtotal

8.2.2

8.2.1

Total capibal group 8.2

8.2.2 equip~nt

funds for Task

year

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

10 30

IO 35

10 45

10 -

Devel~panent and evaluation of expertiaental graphites 8.2.2.2 Study of fabrication processes 8.2.2.3 Characterization of experimental graphites 8.2.2.4 Irradiation of experimental graphites Subtotal

Fiscal

base stock development

10 -

1QQ

aoo

100

10 40 -

10 4Q _I

10 40 -

120 -

120

140

I.40

130

1986

9-25

material used or because of t h e f a b ~ i c a t i o np r o c e s s used. Research q u a n t i t i e s of numerous p r o d u c t s w i l l b e procured for e v a l u a t i o n i n Subtasks 8.2.1.2 and 8.2.1.3. 9.5.5.2

Subtask 8.2.1.2

C h a r a c t e r i z a t i o n of c o m e r f c a l g r a p h i t e s

The csmmerical g r a p h i t e s o b t a i n e d i n Subtask 8.2.1.1 w i l l b e s u b j e c t e d t o several c h a r a c t e r i z a t i o n tests i n t h e u n i r r a d i a t e d c o n d i t i s n i n c l u d i n g p o r e s i z e s p e c t ~ ~ mgas , permeability, c r y s t a l l i n e anisotropy, density, e l e c t r i c a l c o n d u c t i v i t y , and c o e f f i c i e n t of thermal expansion. Some g r a p h i t e s w i l l l i k e l y b e excluded from f u r t h e r t e s t i n g by t h e s e r e s u l t s . For materials t h a t are c a r r i e d f u t h e r , t e s t r e s u l t s w i l l serve as b a s e l i n e information.

9.5.5.3

Subtask 8.2.1.3

I r r a d i a t i o n sf c o m e r i c a l g r a p h i t e s

The g r a p h i t e s used f o r i r r a d i a t i o n tests will b e chosen on t h e b a s i s of a t t r a c t i v e p r s p e r t f e s as i n d i c a t e d by work i n Subtask 8s2.1e2O K because they i n v o l v e r a w materials o r f a b r i c a t i o n p ~ ~ c e s s eofs i n t e ~ e s t . Small c y l i n d r i c a l samples w i l l b e machined for i r r a d i a t i o n Pn HPIR. The samples will be ~ e ~ t o v epde r i o d i c a l l y f o r dimensional measurements. Some samples w i l l b e s u b j e c t e d t o measurements such as d e n s i t y and p o r e spect ~ u mas the i r r a d i a t i o n s c h e d u l e proceeds. The range of experimental v a r i a b l e s w i l l i n c l u d e temperatures of 500 t o 8QO0C and f a s t f l u e n c e s up t o 3.5 x 10" neutrons$cm2. 9.5.6

...

&$..

... ... a

Task 8.2.2

Development and e v a l u a t i o n of e x p e r i m e n t a l graphites

P r e v i o u s s t u d i e s have given encouragement t h a t graphites w i t h improved dimensional s t a b i l i t y can be d e v e l o y e d . There i s l i t t l e f i n a n c i a l inc e n t i v e a t t h i s t i m e f o r csmerical g r a p h i t e f a b r i c a t o r s t o develop such a p r o d u c t , and the work w i l l b e pursued by t h e MSR Program. Research q u a n t i t i e s of graphite will b e produced using w e l l - c h a r a c t e r i z e d materials and p r o c e s s e s . Samples w i l l b e c a r r i e d through e v a l u a t i o n s t e p s s i m i l a r t o t h s s e d e s c r i b e d f o r Task 8.2.1. 9.5.6.1

Subtask 8.2.2.1

Choice of raw materials

S e v e r a l t y p e s sf r a w materials are used i n f a b r i c a t i n g g r a p h i t e . Some of t h e s e materials are h i g h l y g r a p h i t i c ( c r y s t a l l i n e ) and o t h e r s are almost amorphous. The l e s s - g r a p h i t i c materials were once thought t o adversely a f f e c t i r r a d i a t i o n behavior, but recent s t u d i e s i n d i c a t e t h a t t h i s is n o t t h e case under MSBR c o n d i t i o n s . The combined use of highly g r a p h i t i c and amorphous materials a p p e a r s a t t r a c t i v e . The i n t e g r i t y of t h e b i n d e r material is v e r y i m p o r t a n t and i t a p p e a r s t h a t t h e s o - c a l l e d " b i n d e r l e s s g r a p h i t e s " may b e mope r e s i s t a n t to loss of cohesion o r c r a c k i n g between i n d i v i d u a l g r a p h i t e p a r t i c l e s . However, t h e '8bfnderless g r a p h i t e s " undergo l a r g e dimensional changes d u r i n g f a b r i c a t i o n , and

9-26 t e c h n i q u e s must b e developed f o r accommodating t h e s e changes. The choice of r a w materials w i l l a l s o b e based i n f o r m a t i o n from Subtasks % . 2 . 2 . 2 through 8 . 2 . 2 . 4 . 3.5.6.2

Subtask 8.2.2.2

Study sf f a b r i c a t i o n ~ K Q C ~ S S ~ ~

Fornard e x t r u s t i o n , molding, and forward a t r ~ s i o nw i t h back p r e s ~ u r e are t h e most C Q ~ Q Bm e t h ~ d sused f o r f i n a l g r a p h i t e forming. However, t h e entire p r o c e s s flowskeet b v ~ l v e sa myriad of h e a t i n g , mixing, crushi n g , and s i z i n g s t e p s . One sf the key f a c t o r s a p p e a r s t o b e t h e c h o i c e of t h e s e p r o c e s s i n g v a r i a b l e s such t h a t the f i n i s h e d product is i s o t r o p i c on t h e smallest s c a l e p ~ s s i b l e . That I s , g r a p h i t e which i s i s o t r o p i c O R t h e basis O f r e l a t i v e l y l a r g e p a r t i c l e s has i K l f e ? r i Q K d%llM?nSiQnd s t a b i l i t y t o t h a t which is i s o t r o p i c 811 the b a s i s of t h e s m a l l c r y s t a l l i t e s w i t h i n the p a r t i c l e s . This subtask will be involved w i t h study of the entire f a b r i c a t i o n f l o w s h e e t , and its f~nctionwill b e t o supply material f o r the f o l l o w i n g two s u b t a s k s .

9.5.6.3

Subtask 8 . 2 . 2 . 3

Characterization of experimental graphifes

The g r a p h i t e s pb-oduced i n t h e above subtask w i l l b e s u b j e c t e d t o a prsg r e s s i o n a € e v a l u a t i o n tests. The f i r s t tests w i l l b e involved only w i t h a s s e s s i n g s t r u c t u r a l integrity. The subsequent tests w i l l involtre d e t e r m i n a t i o n of b u l k density, POP@ s i z e spectrum, and crystalline a n i s a t r s g y . Additional tests such as c o e f f i c i e n t of theanal expansion, e l e c t r i c a l c o n d u c t i v i t y , and gas permeability may b e r u n QR some of t h e b e a t g ~ a d e s . This i n f o r m t i o n w i l l b e used in Subtasks 8.2.2.1 and 8.2.2.2. The I B O P ~a t t r a c t i v e materials w i l l b e t e s t e d f u r t h e r i n Subtask 8.2.2.4. 9.5.6.4

The gKaphites f o r i r r a d i a t i o n w i l l be chosen on t h e basis Sf a t t r a c t i v e p r o p e r t i e s as i n d i c a t e d by t h e tests i n Subtask 8.2.2.3 or because o r f a b r i c a t i o n processes of i n t e r e s t . Small t h e y i ~ ~ o r al w~materials e c y l i n d r i c a l samples w i l l be machined for i r r a d i a t i o n i n HPIR. The Samples W i l l b e removed pergodieally f o r dhnensiowal m e a S U r e m e R t s . Some? samples w i l l b e s u b j e c t e d t o measurements i n e l u d i n g d e n s i t y and pore spectrum as the i r r a d i a t i o n s c h e d u l e proceeds. The b-ange of e x p e r i m e n t a l v a r i a b l e s w i l l Lnclude t e m p e r a t u r e s of 508 t o 8064'C and f a s t f l u e n c e s up t o 3.5 x 1822 neutrons/em2.

The a b s o r p t i o n of I 3 % e by the core g r a p h i t e c a n r e s u l t i n a s i g n i f i c a n t r e d u c t i o n in b r e e d i n g p e r % ~ ~ m n c e~. o s tof t h e l 3 k e w i l l be removed from t h e f u e l salt by c o n t a c t with helium b u b b l e s , b u t i t w i l l l i k e l y b e n e c e s s a r y t o r e d u c e t h e p e r m e a b i l i t y sf t h e g ~ a p h i t ei n order t o prevent

9-27

t h e a b s o r p t i o n of xenon. It i s l i k e l y t h a t g r a p h i t e having s u r f a c e p e n m e a b i l i t i e s of about cm'/sec w i l l b e r e q u i r e d , and t h i s l o w p e r m e a b i l i t y can o n l y b e o b t a i n e d by (a> impregnatFmg t h e g r a p h i t e w i t h salt, ( b > impregnating t h e g r a p h i t e w i t h carbon, OIL^ ( e > s u r f a c e c o a t i n g t h e g r a p h i t e w i t h pyrocarbon. A l l of t h e s e techniques will b e s t u d i e d t o some e x t e n t .

9.6.2

Objective

The o b j e c t i v e of t h i s t a s k i s t o develop a p r o c e s s f o r d e c r e a s i n g t h e p e r m e a b i l i t y of g r a p h i t e moderator elements w i t h r e s p e c t t o 1 3 5 X e t o a c c e p t a b l y low values (about 10-8 cm2/sec).

9.6.2

Schedule

The schedule f o r work i n t h i s task group i s shown i n Table 9 . 6 . 2 .

9 6.3 e

Funding

Operating fund requirements f o r this task group are shown i n Table 9.6.3.1, and c a p i t a l equipment fund requirements are shown i n Table

9.6.3.2

9.6.4

Facilities

S e v e r a l l a b o r a t o r i e s i n Bbdg. 4508 w i l l b e used f a r t h e development of s e a l i n g t e c h n i q u e s . Samples will b e iPradfEited i n HPIR, removed from t h e experimental c a p s u l e i n t h e h o t c e l l s i n BBdg. 3026I), and returned to Bldg. 4508 f o r p e r m e a b i l i t y measurements. 9.6.5

Task 8.3.1

S a l t impregnation

S a l t c o n t a i n i n g L i p and BeP2 w i l l b e f a r c e d i n t o g r a p h i t e by gas m e r p r e s s u r e . The p e r m e a b i l i t y of helium through t h e impregnated g r a p h i t e w i l l b e measured over t h e temperature range of 580 to 700°C. I f t h e impregnated g r a p h i t e h a s a s u i t a b l y low helium p e r m e a b i l i t y , tests w i l l b e c a r r i e d o u t to determine t h e rate of t r a n s f e r of uranium from a s u r r o u n d i n g f u e l s a l t i n t o t h e impregnated g r a p h i t e . Kesulta from t h e s e two tests must b e a v a i l a b l e b e f o r e f u r t h e r work on t h i s sealimg t e c h n i q u e can be planned.

9.6.6

Task 8.3.2

Carbon impregnation

P r e v i o u s s t u d i e s have shorn t h a t g r a p h i t e can b e s e a l e d by impregnation with carbon d e p o s i t e d from a gaseous mixture. However, subsequent i r r a d i a t i ~ ntests r e v e a l e d t h a t the u s e f u l l i f e t i m e of t h e g r a p h i t e w a s .... ..... A!*

....

..iii. .x.:.>

8.3.2

Carbon

impregnation

9-31 s h o r t e n e d by t h e p r e s e n c e of t h e impregnant. This t e c h n i q u e can l i k e l y b e used only i f t h e p e n e t r a t i o n of the d e p o s i t e d carbon i s v e r y s l i g h t and t h e b a s e g r a p h i t e does n o t c o n t r a c t a p p r e c i a b l y d u r i n g i r r a d i a t i o n . This t e c h n i q u e f o r s e a l i n g g r a p h i t e would b e pursued a t a very low l e v e l w i t h v a r i a t i o n s in impregnation t e c h n i q u e and b a s e s t o c k . I r r a d i a t i o n i n HPIR w i t h p e r i o d i c gas p e r m e a b i l i t y measurements w i l l b e t h e prime method of e v a l u a t i o n .

9.6.7

Task 8 . 3 . 3

Carbon c o a t i n g s

Pyrocarbon c o a t i n g s have been placed QHZ g r a p h i t e w i t h moderate s u c c e s s . Dense impervious c o a t i n g s can b e formed, b u t t h e i r helium p e r m e a b i l i t y i n c r e a s e s d u r i n g i r r a d i a t i o n . Many of t h e f a i l u r e s were t r a c e d t o f l a w s i n t h e c o a t i n g ; hence, emphasis will b e placed on developing c o a t i n g t e c h n i q u e s which minimize f l a w s . Only one g r a p h i t e s u b s t r a t e w a s s t u d i e d p r e v f o u s l y (POCO hnxp), and o t h e r materials w i l l b e ineluded in f u t u r e s t u d i e s . Samples w i l l b e i r r a d i a t e d i n HPIR and removed p e r i o d i c a l l y f o r p e r m e a b i l i t y measurements. .....

The p o t e n t i a l of u s i n g decoupled c o a t i n g s w i l l b e s t u d i e d . The f i r s t pyrecarbon l a y e r w i l l b e of low d e n s i t y and e a s i l y deformable. The seesnd l a y e r w i l l b e of h i g h d e n s i t y and impervious t o xenon. Techniques w i l l be developed f o r a p p l y i n g t h i s t y p e of c o a t i n g , and coated samples w i l l be i r r a d i a t e d . E v a l u a t i o n w i l l b e made by p e r i o d i c removal of the samples f o r p e r m e a b i l i t y measurements. Scaled-up c o a t i n g t e c h n i q u e s w i l l b e developed f o r t h e most a t t r a c t i v e process. The c o a t i n g s must u l t i m a t e l y b e a p p l i e d t o moderator elements s e v e ~ a lf e e t long, and m u l t i p l e i n j e c t o r s w i l l b e n e c e s s a r y f o r o b t a i n ing satisfactory coatings.

9.7

TASK GROUP 8 . 4

PHYSICAL PROPERTIES

The p h y s i c a l p r o p e r t i e s of g r a p h i t e cover a wide range due t o the Barge s t a r t i n g materials and f a b r i c a t i o n techniques used i n g r a p h i t e manufacture. The p h y s i c a l p r o p e r t i e s p r o v i d e u s e f u l i n f o r m a t i o n about the c r y s t a l l o g r a p h i c s t r u c t u r e and o t h e r p r o p e r t i e s . S i m i l a r l y , t h e changes i n p h y s i c a l p r o p e r t i e s d u r i n g i r r a d i a t i o n p r o v i d e i n f o r m a t i o n about t h e c r y s t a l l o g r a p h i c changes which occur. Thus, p h y s i c a l propert i e s suck as thermal expansion, thermal c o n d u c t i v i t y , and e l e c t r i c a l r e s i s t i v i t y are v e r y u s e f u l f o r c h a r a c t e r i z i n g g r a p h i t e and f o r evalua t i n g s t r u c t u r a l changes d u r i n g i r r a d i a t i o n . The changes sf t h e s e p r o p e r t i e s are a l s o of d i r e c t importance to t h e design of a r e a c t o r core, s i n c e t h e y a f f e c t dimensional b e h a v i o r and h e a t t r a n s f e r . A program w i l l b e c a r r i e d OII i n which g r a p h i t e samples are a l t e r n a t e l y i r r a d i a t e d and p h y s i c a l p r o p e r t i e s measured. R U K ~ X of

';.... &

....

9-32

9.7.1

Objective

The objective sf t h i s task group is t o determine how irradiation changes the physical p r o p e ~ t i e sof g r a p h i t e . 9.7.2

The schedule for work in this task group is shown in Table 9 . 7 . 2 .

Operating fund requirements for this task ~ P O U ~ given in Table 9.7.3.1 and capital equipment fund r e q ~ i ~ e w e nare t ~ given in T a b l e 9.7.3.2. 9.7.4

Facilities

This work w i l l make use of t h e P h y s i c a l Properties Laboratory in Bfdg. 4588. Samples will be irradiated in HFIR, removed from t h e i~radfation capsule in the h o t c e l l s in Bldg. 3 8 2 6 , and returned to Bldg. 4508 f o r postirradiation measurements.

9.9.5

Task 8 . 4 . 1

T h e r m a l conductivity m e a s u ~ e ~ e n t s

The t h e ~ m lconductivity 0% the core graphite will have a direct bearing on the peak temperature in the g r a p h i t e . The rate sf d2mensisraal change raphite increases with i n ~ ~ e a s i r ntemperature, g s o the thermal conivity and t h e a%hwabHe neutron fluence are related. Irradiation is bow^ to decrease t h e thermal conductivity b u t this e f f e c t i s thought ipment to saturate at fluenee values s f about 10’0 ~ ~ U ~ K O I I S~/q C~ ~ f o r making thermal conductivity measurements and i r r a d i a t h n c a p s u l e s f o r exposing samples have been proven satisfactory. About three grades saphite will be i r r a d i a t e d at 550, 4 5 0 , and 750°C to fluenaces rom 1 x 10’9 to 3.5 x 102’ neutrons/em2. me samples w i l l b e e r i o d i c a l l y f o r therm% c ~ n d u c t i v i t ymeasurements. A g o a l of t h i s WOrk % S i l l $62 t 0 relate Changes ill t h e m d COnduCtiVity to 88me basic characteristic of the graphite such as t h e raw material used in i t s -inaraufacture e

9.7.6

Task 8.4.2

Thermal expansion

8 c4

d 8

m .-i rl

-3-

9-34

a wi

9-35 .... m!

dimensional changes t h a t w i l l occur d u r i n g i r r a d i a t i o n . The c o e f f i c i e n t of thermal expansion i s also a n e c e s s a r y parameter f o r d e s i g n p u r p s e s .

Heasuring equipment and i r r a d i a t i o n t e c h n i q u e s have been developed f o r i n c r e m e n t a l l y f o l l o w i n g t h e thermal expansion of g r a p h i t e d u r i n g i r r a d i a t i o n . Samples of t h r e e g r a p h i t e s w i l l b e measured, i r r a d i a t e d i n BFPR, and removed p e r i o d i c a l l y i n o r d e r t o r e p e a t t h e measurements. (The same samples used i n t h e above t a s k w i l l b e used f o r t h e s e measurements.)

9.7.7

Task 8.4.3

Electrical conductivity

E l e c t r i c a l c o n d u c t i v i t y of g r a p h i t e is a measure of t h e m o b i l i t y of e l e c t r o n s through t h e material and i s a r a t h e r basic parameter. T h i s p r o p e r t y 1s c l o s e l y r e l a t e d t o t h e thermal c o n d u c t i v i t y and t h e measuring t e c h n i q u e s f o r thermal c o n d u c t i v i t y are such t h a t e l e c t r i c a l c o n d u c t i v i t y measurements can b e o b t a i n e d a t t h e same t i m e . Thus, t h e experimental p l a n d e s c r i b e d i n Task 8 . 4 . 1 would b e a p p l i c a b l e t o d e t e r m i n a t i o n of electrical conductivity. 9.7.8

Task 8.4.4

Elastic properties

The e l a s t i c p r o p e r t i e s of g r a p h i t e are used i n numerous d e s i g n calculat i o n s , the most important one b e i n g t h e magnitude of t h e stresses developed i n t h e moderator elements due t o d i f f e r e n t i a l dimensional changes a c r o s s the element. The e l a s t i c p r o p e r t i e s a r e a f f e c t e d by i r r a d i a t i o n and t h i s v a r i a b l e w i l l b e i n c l u d e d i n t h e t e s t program. Sonic methods w i l l l i k e l y b e used to measure t h e e l a s t i c c o n s t a n t s . A sound wave i s p u l s e d through a sample and t h e t i m e s f o r o b t a i n i n g r e f l e c t e d waves i n t h e t r a n s v e r s e and l o n g i t u d i n a l d i r e c t i o n s are measured. These d a t a define t h e V e l Q c i t y of sound in the t w o d i r e c t i o n s , and these Values can be used t o c a l c u l a t e Youngs and s h e a r moduli. These two e l a s t i c c o n s t a n t s a l l o w c a l c u l a t i o n of a l l o t h e r e l a s t i c c o n s t a n t s . The s m a l l c y l i n d r i c a l samples used i n T a s k 8 . 2 and 8 . 3 would b e used fsr ~ I a e s e measurements. A key p a r t of t h e measuring t e c h n i q u e i s n o t y e t worked o u t which concerns t h e means of c o u p l i n g a t r a n s d u c e r t o t h e sample f o r t r a n s m i t t i n g amd r e c e i v i n g t h e sound p u l s e . The method c u r r e n t l y i n u s e would contaminate t h e sample and would p r e v e n t f u r t h e r i r r a d i a t i o n of t h e sample.

9.8

TASK GROUP 8.5

EVALUATION TESTS FOR MSBR G W H L T E

S e v e r a l tests must b e made on t h e g r a d e of g r a p h i t e chosen f o r t h e molten-salt t e s t r e a c t o r and for t h e r e f e r e n c e d e s i g n MSBR. The work c a r r i e d o u t i n Task Groups 8.1 through 8.4 w i l l have invesPved s m a l l samples. Tests of a proof n a t u r e w i l l b e r u n QII l a r g e p i e c e s having t h e f u l l IXQSS s e c t i o n of a moderator element. These tests w i l l i n s l b d e long-term i r r a d i a t i o n tests on uncoated and coated elements, and subs e q u e n t e v a l u a t i o n of t h e i r r a d i a t e d specimens.

9-36

9 8 1

Objective

9.8.2

Schedule

The s c h e d u l e f o r work i n this task

9.8.3

roup 2s shown i n Table 9 . 8 . 2 .

Funding

crating fund requirements f o r t h i s t a s k group a r e shown in Table 9.8.3.1, and c a p i t a l equipment fund requirements are s h m i n Table 9 . 8 . 3 . 2 . r his i n c l u d e s c a p i t a l equipment funds i n t h e amount of $300,000 i n b o t h ET 1980 and FY E981 f o r c o n s t r u c t i o n of two f a c i l i t i e s for i n %eactQKirKadiatiOn of Parge IllsdePEitQP g r a p h i t e s k ? C t i O n s .

9.8.4

Facilities

F a c i l i t i e s will b e r e q u i r e d f o r i r r a d i a t i o n of l a r g e - s c a l e p r o t o t y p i c moderator g r a p h i t e elements, and t w o i n s t r u m e n t e d , i n - r e a c t o r test f a c i l i ties Capable O f independent t@mpeKatUre C O n t P O E W i l ] l be COflStKuCted. Location of the f a c i l i t i e s in t h e Om, t h e WIR, OK a Savannah River reactor appears p o s s i b l e .

9.8.5

Task 8.5.1

Large-scale i r r a d i a t i o n t e s t h g

The i r r a d i a t i o n testing performed i n o t h e r tasks has i ~ ~ l v small e d test samples, however, some proof t e s t i n g on large elements will be n e c e s s a r y . The main v a r i a b l e n o t e v a l u a t e d by t h e s m a l l samples i s f a b r i c a t i o n i n homogeneities. Density g ~ a d i e n t s ,v a r i a t i o n s i n p o r e s i z e d i s t r i b u t i o n and o t h e r inhomogeneities can be present i n large elements. Large elements that have been s e a l e d t o p r e v e n t xenon permeation can have areas i n which the coating w i l l v a r y i n i t s dimensional s t a b i l i t y d u r i n g irrad a t i o n . These c o a t i n g inhomogeneities could lead t o earlier l o c a l i z e d c o a t i n g f a i l u r e s t h a n p r e d i c t e d from d a t a f o r small specimens.

9.8.5.1

Subtask 8.5.1.1

h..

B a s e graphite

G r a p h i t e samples having t h e full cross s e c t i o n of an MSBR moderator element and about 2 ft long w i l l be i ~ r a c l i a t g di n t h e core of t h e 0 and likely some o t h e r r e a c t o ~having a larger i r r a d i a t i o n f a c i l i t y (e.g., a Savannah River r e a c t o r ) . It is l i k e l y t h a t the e x g e r h e n t s w i l l b e instrumented t o o b t a i n continuous d a t a on dimensional changes. The experiments will l i k e l y be r e m ~ v e dp e r i o d i c a l l y for d h e n s f o n a l measureexperiments ments and replacement of in-reastor i n ~ t ~ u m e n t a t i ~ gThese l. will l i k e l y i n v o l v e t w o t o four elements of the r e f e r e n c e g r a p h i t e , w i l l

Table 9.8.2.

Schedule for work in Task Group 8.5 - Evaluation

8.5.1

Large scale irradiation testing 8.5.1.1 Base graphite 8.5.1.2 Coated elements

8.5.2

Analytical graphite

evaluation

of reference

tests

for MSBR graphite

Table

9.8.3.1.

Operating

fund requirements EQP Task tests fQP MSBR graphite (casts in 1000 dollars)

1979 8.5.1

Large 8.5.1.1 8.5.1.2 Subtotal

8.5.2

Total

Analytical graphite

scale irradiation Base graphite Coated elements

operating

funds

Table

9.8,%.2.

far

Large 8.5.1.1 8.5.1.2

Total capital Group 8.5

Task

Group

Capital

Fiscal

year

1980

1981

1982

19 8%

B984

1985

1QQ 100

2QQ 200 400

2QQ 2QQ 400

2QQ 200 4QQ

100 200 ____ 380

-_ 1OQ

75 s_ 475

100 500

1QO 588

100 500

100 400

8.5

equipment fund requirements tests for MSBR graphite (casts in 11000 dollars)

scale irradiation Base graphite Coated elements

testing

equipment

for

funds

- Evaluatian

1986

reference

1979 8.5.1

8.5

testing

8.5.1 evaluation

Group

Task

for

Task

Group

8.5

Fiscal

year

Evaluatisn

198Q

1981

1982

198%

1984

11985

300 70 -

300 20 70 -

20 20 -

20 2Q -

20 20 -

370

390

1986

9-39 .:..... :.:*

b e exposed over t h e t e m p e r a t u r e range of 500 t o 950’6, and w i l l b e i r r a d i a t e d t o a f l u e n c e of about 3 x 10” neutrons/cm2 over a p e r i ~ dof several y e a r s a

9.8.5.2

Subtask 8.5.1.2

Coated elements

Samples of t h e r e f e r e n c e g r a p h i t e w i l l b e c o a t e d by t h e most promising t e c h n i q u e s and i r r a d i a t e d i n t h e same t y p e of experiment as d e s c r i b e d in Subtask 8 . 5 . l . 1 . The specimens w i l l have t h e f u l l cross s e c t i o n of a moderator element and w i l l b e a t l e a s t 1 - f t long. They w i l l a l s o c o n t a i n a s m a l l c e n t e r annulus w i t h l i n e s f o r c o l l e c t i n g and a n a l y z i n g t h e gas from t h i s annulus. The p e r m e a b i l i t y w i l l b e determined i n s i t u from t h e knowledge of t h e geometry, t h e p r e s s u r e d i f f e r e n t i a l , and t h e r a t e of i n g r e s s of gas i n t o t h e i n n e r annulus. These experiments w i l l r u n f o r several y e a r s t o ~ ~ u e n c eofs 3 . 5 x neutrons/cm2. S i n c e t h e p e r m e a b i l i t y measurements w i l l b e made i n s i t u , t h e experiments w i l l be removed o n l y a f t e r t h e p e r m e a b i l i t y becomes t o o h i g h f o r t h e experiment t o b e of i n t e r e s t o r when t h e i n s t r u m e n t a t i o n must b e r e p l a c e d . 9.8.4

Task 8-5.2

A n a l y t i c a l e v a l u a t i o n of r e f e r e n c e g r a p h i t e

The l a r g e - s c a l e i r r a d i a t i o n experiments in Task 8.5.1 w i l l p r o v i d e data of unique v a l u e f o r a n a l y t i c a l l y a n a l y z i n g t h e performance of g r a p h i t e i n a r e a c t o r . The a b i l i t y of g r a p h i t e t o c r e e p under i r r a d i a t i o n i s r e q u i r e d t o r e l a x stresses t h a t develop due t o a n i s o t r o p i c dimensional. changes. The elements i n t h e s e experiments w i l l e x p e r i e n c e a n i s o t r o p i c dimensional changes and t h e demonstrated a b i l i t y of t h e g r a p h i t e t o a c c o m o d a t e t h e s e dimensional changes w h i l e remaining i n t e g r a l w i l l b e sf extreme v a l u e . The demonstrated l i f e t i m e of t h e c o a t i n g s w i l l allow a r e a l i s t i c assessment of t h e economics of g r a p h i t e replacement a t a given fluenace versus continued operation at a B o w e r performance. The i n f o r m a t i o n o b t a i n e d from t h e s e experiments w i l l be analyzed w i t h regard t o performance and made a v a i l a b l e f o r u s e i n r e a c t o r d e s i g n and a n a l y s i s ( S e c t i o n 8).

9-40 REFERENCES FOR SECTION 9

G. B. Engle and W. P. EatherPy, ''A R e v i e w of High-Temperature G r a p h i t e I r r a d i a t i o n Behavior" i n High Temperature-High P r e s s u r e s (to be published).

J . M. W. S i m o n s , Radiation Damage i n Gpaphite, Pex-gamon P r e s s (1965).

Conceptual Desigfi Studz.~ o f a S & q k F l u i d Molten-Salt Reactor, OWNE-4528 (1978).

""1008 m(e)Molten-Salt Breeder Reactor G ~ n c e g t ~ aDesign P Study, '' F i n a l Report -Task I., Ebasca Services, %ne. (1971).

D. S c o t t and W. B. Eatherly, JJucl. AppZ. Tech. 8: 179 (l970).

W. P. E a t h e r l y et ale, Technical. Analysis and Progp?am Proposal: Gmphite fo~"Mottan-SaZt Reactors, QRNL-CF-68-18-18 (1968).

12.

MB P r o g P m Semiannu. PPogP. R e p t . Feb. 28, 2969, OWL-4396.

13.

K R a a o g ~ mSemiannu, P ~ o g r .R e p t . Aug. 32, 2 9 7 0 , QRNE-4622.

14.

W R P ~ o g ~ aSemknnu. m L32og~. W e p t . Feb. 29, 1 9 7 2 , O1RNL-4782.

10. REACTQR TECHNOLOGY DEVELOPMENT 18.1

HNTRODUCTPQN

10 * 1 I 8bj ective e

The o b j e c t i v e of this activity is development of the technology necessary for designing and specifying the performance of components and systems

which would constitute molten-salt reactors including a test reactor, a demonstration reactor, and a 1000-W(e) MSBR. 10.1.2

Scope

This activity covers all development work associated with reactor systems and components except for that dealing with fuel processing and instrumentation development, which are covered in Sections 3 and 12, respectively. In general, determination of basic physical propestlfes of salts and the development of materials of construction fall outside this activity; however, some information of this type will result from work in t h i s activity. Although the requirements f o r components and systems will b e specified largely by conceptual design studies for the various molten-salt reactors considered in the activity Reactor Design and Analysis (Section 8 ) , d e l i t i o n a l conceptual design studies would be carried o u t as necessary f o r identifying problem areas in proposed component designs and f o r preperly orienting the component technology development. In general, work in this activity proceeds from small equipment, which involve tests with ~ ~ U ~ O solution^ U S rather than ~ ~ l t e n - s a l tthrough successively larger equipment sizes and culminates in tests u s i n g molten s a l t an a scale sufficiently large to allow detailed component design for test ana demonstration reactors.

After operation of the molten-salt test reactor (see Section 14) and test reactor mockup (see Section 131, additional de~elop~~ent work will be required to scale up equipment which functioned satisfactorily, to develop item the need for which is not now knom, and to make improvements required f o r a demonstration reactor. This work is covered in Seetion 15.

In a18 of the development activities, tndustrial participation through government-sponsored subcontracts as well as industry-sponsored work will be solicited and encouraged. A l l large components w i l l be purchased from logical vendors, ff availables in order to establish a source for future reactor components.

The work associated w i t h t h i s activity area is divided into the following task groups:

10-2 ....

Is.:".

Fuel Salt Technology Development (Task Group 9.1) Coolant Salt T @ ~ h ~ ~ ~Development logy (Task G K O U ~9.2) S t e m System Technology Develbopment (Task Group 9 . 3 ) Cover and Off-Gas Systems Technology Devehqm~ent (Task Group 9 . 4 ) S a l t Pump Development (Task Group 9.5) P r h a r y S a l t - S a l t Heat Exchanger D e ~ e E ~ p m e(Task ~ ~ t Group 9.6) Valve Development (Task Group 9.7) Contro4i Rod Development (Task Group 8.8) Containment and Cell Heating Development (Task Group 9.9) C O I l l ~ O H l e n t s T e s t PaCilftyP (Task Group 9.10) 10.1.3

R e l a t i o n t o o t h e r a c t i v i t y areas

There is a c l o s e r e l a t i o n s h i p between all activity areas %nt h i s p r o g ~ m p l a n , and c a r e f u l coordination of the work is n e c e s s a r y . I n many cases t h e need f o r r e a c t o r technology development may o ~ i g i n a t ei n o t h e r activity areas and, c o n v e r s e l y o t h e reactor development a c t i v i t i e s m y d i c t a t e additiunal work elsewhere, such as chemical research o r safety analysis. Muck of the instrumentatSon and c o n t r o l s development ( S e c t i o n 12) as w e l l as t h e maintenance p ~ o ~ e d u r e(Section s 11) w i l l b be governed by the r e s u l t s 0% reactor technoPo y development work. Especially close c o n t a c t w i l l be maintained with the a c t i v i t i e s on r e a c t o r d e s i g n and analysis and on r e a c t o r safety.

10.2.1

Schedule

The work in t h e Molten-Salt Reactor Program i n t h e n e a r f u t u r e w i l l be of a technology n a t u r e ; and, d u r i n g t h i s p e r i o d , work in the Reactor Technology Development a ~ e w~i li l be concerned mainly w i t h development a d testing in the Gas-System Technology Facility, which c i r c u l a t e s fuel salt and i n the Coolant-Salt Technology F a c i l i t y , which c i r c u l a t e s coola n t s a l t . Work in t h e s e facill8ti.e~w5lb be phased out during t h e p e r i o d ET 197% t o 1981. Other small-scale development of components and systems w i l l begin i n the p e r i o d FY P977 t o 1979, u s i n g s m a l l separate f a c i l i t i e s . L a r g e r - s c a l e emponent development w i l l be done in the Components T e s t F a c i l i t y which w i l l be completed d u r i n g 1982.

The s t e m g e n e r a t o r and salt pump development. a c t i v i t i e s appear ts be critfcal p a t h i t e m s , and work on t h e s e cmganents w i l l be e a ~ r i e dout as rapidly as funds allow. S m e s t e m generatar s t u d i e s will be dune d u r i n g ET 1975, w i t h t h e work effort i n c r e a s i n g r a p i d l y i n o r d e ~t o effect t h e t i m e l y development of technology r e q u i r e d f o r d e s i g n of a mo%tew-salt test reactor. Salt p m p procurement a c t i v i t i e s w i l l begin tn 1998, which ~ h ~ a~l l olw dtesting sf an MSTR p r o t o t y p e pump to begin i n FY 1983.

.... E ,%

Teble

10.2.1.

Schedule

for

work

on reactor

technology

1979

1980 I

9.1

Fuel

salt

technology

9.2

CooBank

salt

kechno]logy

9.3

Steam

system

technology

9.4

Cover-

and off-gas

9.5

Sdk

pump devefopmenk

9.6

Primary

heat

9.7

Valve

deve8opmenk

9.8

Control

9.9

Ccmkainmenk development

and cell

9.10

Components

Tesk Facility

rod

---p+--i

systems

exchanger

kechnohgy

development

development heeking

development

1981 I

1982

1983

10-4

PO 2 . 2 0

Funding

Operating fund requirements f o r work on r e a c t o r technology development are shorn i n Table liQ.2.2.1, and c a p i t a l equipment fund ~ e ~ p i r m e n t ~ are shorn in Table 16.2.2.2.

Large c a p i t a l a p p r o p r i a t i o n s are r e q u i r e d i n IPII 1979 f o r the Stem Generator Tube T e s t Stand ( $ 4 million), i n ??Y 1986 f o r the Pump T e s t Stand ($1 million) and the Components Test Facility ($10 m i l l i o n ) , and 5n FY I981 f o r the Mode1 steam Generator %est L n s t a l l a t i o n ($20 million).

10.2.3

Key miliestones

The milestones in t h f s activity area are l i s t e d below by r e s p e c t i v e t a s k group and are i n d i c a t e d by corresponding numbers tn P i g . 10.2.1.

The Gas-Systems Technology F a c i l i t y waeerr tests dll be f i n i s h e d and c o n s t r u c t i o n completed so that s a l t o p e r a t i o n can s t a r t e a r l y in FY 1976.

y t h e end O f m 1977 s u f f i c i e n t tests w i l l have been completed t o i n d i c a t e that t h e e f f i c i e n c y of the bubble generator-bubble separator i s s a t i s f a c t o r y and t h a t m a s s transfer rates are adeq u a t e t o p e r n i t d e t a i l e d design of t h e xenon removal system f o r a m o l t e n - s a l t t e s t r e a c t o r . A d d i t i o n a l development d P 1 be done to r e f i n e %he r @ s u l t s aR t e s t the effects of o t h e r v a r i a b l e s .

EO 2 3 . 2 D

1. Tests for determining t h e behavior of tritium in t h e csslant system trill. be completed by the end of

Large-scale d m o n ~ t r a t i ~t en s t s of c o o l a n t salt technology S ~ Q U P ~ be cmpleted by t h e end of E!? 1984.

....

Table

10.2.2.1.

Operating

185

230

23Q

technology

.I69

290

106)

teehn0logy

280

580

600

saa

120 40

9.1

Fuel

tedmo1olgy

9.2

Coolant

salt

9.3

Steam system

9.4

COV~P- and off-gas

e&t

fund requirements far work an reactor (costs in 1000 dollan3)

system

technology

9.5 9.6

PKfmaKy heat

160

40 ContKoa

9.9

Containment development

440

200

250

2QQ

1QQ

200

1098

12QQ

1200

110

B4Q

625

1225

1075

3QO

56)

1QQ

180

100

288

15Q

150

100

.!a

100

1QQ

rod development

9.18) Components

and sell test

C!QQ

3QQ

heating

facility

Total operating funds for technology aevel~pment

deveBopment

150

exckangelP development

9.7 9.8

250

technolagy

reaeta-

IQ0

___

120 ---

200

208

445

725

16118 --

2300

41Q

8QQ

9aro

1080

1440

2595

3735

35QQ

3750

46880

40068

9.1

Fuel salt technalagy

9.2

Coolant salt tecbnalo~

9.3

steam system tedmalagy

9.4

COV@K- and Qff-gas

9.5

Salt

9.6

PKimaKy

9.7

Valve

development

9.8

Control

rod

9.9

Containment

and

cell.

9.10

Components

Test

Facility

TotaB capital technology

system

te&mlogy

200

25Q

pu4lp development

bezig: exchanger

caevePopment

xl 2.50

developm@nt

equipment development

2SQ beating

funde

for

devePapment

reactor

77 -

411 __

579 --

1Q 23

290

425

671.

829

1823

By the end of FY 1976, t h e i n d u s t r i a l r e s o m e n d a t i o n f o r a s t e m g e n e r a t o r research and d e v e l o p ~ ~ program e~t should be completed.

By t h e end of FY 1979, the sma%%-seales t e a m g e n e r a t o r work should permit r e e v a l u a t i o n of t h e have p r o g r e s s e d t o 8 stage Which r e s e a r c h and development program.

The c o n s t r u c t i o n of t h e S t e m Generator Tube T e s t Stand, p r e s s u r e r e l i e f system, and t h e 3-MM test assembly should be cmp1ete by t h e middle of FY 198%.

T e s t i n g i n t h e S t e m Generator Tube T e s t Stand S ~ Q U P be~ f i n i s h e d by mid IFY 1983.

C o n s t r u c t i o n of t h e S t e m Generator Model 'Pest Installation, t h e p r e s s u r e r e l i e f system, and t h e 38-MW model stem generator should b e complete by t h e end of 1983, and o p e r a t i o n a l tests w i l l be started

10.2.3.4

Task Group 9 . 4 d eve1opmen t

Cover and off-rpas systems technology

1. Development of methods f o r handling gaseous e f f l u e n t s ( i n c l u d i n g f i s s i o n p r o d u c t s , t r i t i u m , and BF3) from t h e off-gas systems should b e complete by t h e end of Z" 1 9 8 2 . 2.

o t h e r problems associated w i t h t h e cover and off-gas systems should be r e s o l v e d by t h e end of I T 1984.

hpll

10.2.3.5

Task Group 9.5

S a l t pump d e ~ e h p m e ~ ~ t

1. The d e s i g n of the HSTR p r o t o t y p e pump and pump test stand should be complete by t h e end of I T 1981.

The c o n s t r u c t i o n of the MSTR p r o t o t y p e pump and pump test s t a n d should be cmpleted by the end of FY 1983, and o p e r a t i o n a l tests w i l l be s t a r t e d .

10.2.3.6

Task Group 9.6

B r b a r y salt-salt h e a t exchanger development

1. A I 1 develsment work on t h e primary h e a t exchanger p r e p a r a t o r y t o d e s i g n sf the PlSTR w i l l be e m p l e t e d by the end of FY 1983.

PO -8

%Q.2.3.7

Task Group 9.7

Valve development

l, Pre%iri-iLnary valve development needed to proceed with design of t h e MSTR will b e f i n f s h e d by t h e end of 'gsy 1979. 2.

F i n a l development of s p e c i f i c valves for t h e PETR will b e finished by t h e end Of rn 1984.

Task Group 9 . 9

10.2.3.9 1.

C~ntainmerttand cell heating

Exploratory studies and preliminary development needed f o r the d e s i g n of t h e MSTW containment and cell heating s h o u l d be comp l e t e d by t h e end of FY 1982.

10.2.3.10 1.

Task Group 9.10

Components Test Facility

The d e s i g n of t h e Components Test Facility s h o u l d be sufficiently complete to s t a r t construction in mid PY 1988. k.2

2. C~nst~-~ctfon of the Components Test Facility should b e eomp%eted by t h e middle of FY 1982.

10.3,Ib

F u e l s a l t technology development

The i.%sRE w a s o p e r a t e d from 1964 to 1969 using a fuel s a l t similar to that proposed f o r the WBW. When it w a s s h u t down in D e c e d e r of 1969, the reactor had accumulated 13,192 full-power fnsurs of operation and salt had been circulated in t h e fuel s y s t e m f o r 21,788 h o u r s . I Although the MS was operated successfully u s i n g a f u e l salt containing 2 3 5 ~and later the %BR fuel s a l t which r e q u i r e additional study. The MS tained about 5 mole X ZrF, f o r p r e v e n t i n g U82 p r e c i p i t a t i o MSBR s a l t does not contain 2 3 8 4 . me proposed o p e r a t i n g temperature and p a g e r d e n s i t y of the MSBW are higher a d t h e method f o r removing gaseous fission prsducts is somewhat more complicated. These diffe~ences,toether w i t h s t h e r uncertainties, dictate a nmber of developmental tasks associated w i t h the fuel s a l t system.

10 -9 I n a r e a c t o r which o p e r a t e s i n t h e thermal energy range, continuous removal of t h e gaseous f i s s i o n p r o d u c t , xenon-13.5, i s n e c e s s a r y t o o b t a i n a b r e e d i n g r a t i o g r e a t e r t h a n 1.0. In a m o l t e n - s a l t b r e e d e r ~ e a c t o r (MSBR), t h e xenon-125 c i r c u d a t e s i n s o l u t i o n w i t h t h e molten f l u o r i d e f u e l s a l t , and t h e proposed xenon removal method c o n s i s t s of c i r c u l a t i n g a low volume f r a c t i o n (0.2 to 1% a t c o r e midplane) of helium bubbles w i t h t h e s a l t t o s e r v e as .a s p a r g i n g a g e n t . The x e n ~ n - 1 3 5 and o t h e r gaseous f i s s i o n p ~ o d u c t swould t r a n s f e r from the s a l t t o t h e helium bubbles by t u r b u l e n t d i f f u s i o n and would b e s t r i p p e d from t h e s a l t bubble m i x t u r e when t h e bubbles a r e removed. C a l c u l a t i o n s , based on c u r r e n t l y a v a i l a b l e i n f o r m a t i o n , have shown t h a t s t r i p p i n g t h e bubbles from a 10% s i d e stream would reduce t h e xenon p o i s o n i n g t o an a c c e p t a b l e l e v e l and that l i t t l e advantage would b e gained by stripping l a r g e r streams. Supplementary i o d i n e s t r i p p i n g would b e needed o n l y i f s a t i s f a c t o r y methods cannot b e developed f o r s e a l i n g t h e c o r e g r a p h i t e w i t h r e s p e c t t o xenon permeation, Work on xenon s t r i p p i n g has been c o n c e n t r a t e d on the development and aqueous t e s t i n g of i n - l i n e bubble g e n e r a t o r s 2 and bubble s e p a r a t o r s e 3 Based OBI tests of v a r i o u s bubble g e n e r a t o r t y p e s under d i f f e r e n t o p e r a t i n g condition^ and u s i n g d i f f e r e n t aqueous s o l u t i o n s , a v e n t u r i - t y p e g e n e r a t o r was s e l e c t e d f o r f u r t h e r t e s t i n g i n s a l t . The bubble s i z e produced by the bubble g e n e r a t o r i s b e l i e v e d t o have a minor i n f l u e n c e on t h e o v e r a l l operation o f a xenon removal system because of bubble d e g r a d a t i o n and ~ o ~ n p r e s s i odnu r i n g passage of t h e bubbles through t h e primary pump and o t h e r changes i n bubble s i z e t h a t may occur because of c o a l e s c e n c e , gas s o l u b i l i t y , and p r e s s u r e Changes. Tests of bubble s e p a r a t o r s have been conducted u s i n g demineralized water and two modeling f l u i d s , a 41% glycerin-water m i x t u r e and a 31% aqueous calcium c h l o r i d e s o l u t i o n , b o t h having kinematic v i s c o s i t i e s e q u i v a l e n t to MSBR f u e l s a l t a t 1225°F. Tbmese tests would b e c o n s e r v a t i v e i n r e g a r d to bubble s e p a r a t i o n e f f i c i e n c y a t higher salt temperatures. The brabble d i a m e t e r s a t the bubble s e p a r a t o r i n l e t u s i n g t h e t e s t f l u i d s w e r e a b o u t 0.001 t o 0.005 i n . as compared w i t h a b o u t 8.020 i n . i n demineralized water Since t h e bubble size characteristfcs in a molten-salt system w e r e unknown

a t t h e t i m e , development tests w e r e continued w i t h t h e small bubbles a s s o c i a t e d w i t h the CaC%, solution r a t h e r t h a n s e a r c h i n g f o r a s u i t a b l e f l u i d having bubble s i z e s more n e a r l y equivalent t o t h o s e observed w i t h w a t e r . Based on t h e s e t e s t e , a n axial-flow-, c e n t r i f u g a l - t y p e bubble s e p a r a t o r w a s designed f o r t e s t i n g i n the Gas-System Teehnolsgy F a c i l i t y C a C l 2 s o l u t i o n tests on t h i s design showed bubble s e p a r a t i o n e f f i c i e n c i e s of g r e a t e r t h a n 80% under n o r m l o p e r a t i n g c o n d i t i o n s . sed on ir benchscale comparison test of bubble f o r ~ ~ t i oand n c o a l e s c e n c e , a h i g h e r separ a t i o n e f f i c i e n c y i s expected w i t h molten s a l t . Bubble s i z e d e t e r m i n a t i o n would a i d i n f u r t h e r s e p a ~ a t ae ~ v a l u a t i o n ; however, i n s t r u m e n t a t i o n of this t y p e does not appear t o b e a v a i l a b l e . e

:..... :.=

..... w

..... .:.... .:.:.:,

Very l i t t l e q u a n t i t a t i v e i n f o r m a t i o n i s a v a i l a b l e r e g a r d i n g t h e distrib u t i o n of tritium i n MSR systems. The amount of tritium t h a t could r e a c h the steam system O f t h e KefereIICe d e s i g n Ms63%2 is e s t h 2 l t e d t o b e about one-third of t h e 2420 Ci/day p r o d u c t i o n r a t e i n t h e f u e l s 4 Tests made shortly b e f o r e t h e MSRE w a s s h u t down i n d i c a t e t h a t about h a l f of

PO-20

t h e tritium w a s d i s c h a r g e d from t h e f u e l off-system.5 L e s s than 18% d i f f w e d through the metal w a l l s of the f u e l system t o t h e containmentcell atmosphere, and less than l33Xhed the ai9 thT.X2Ugh t h e h e a t removal s y s t e m - More q u a n t i t a t i v e i n f o m t i o n r e g a r d i n g tritium b e h a v i o r i n Parge m o l t e n - s a l t systems i s needed.

The f i s s i o n p r o c e s s i s mildly o x i d i z i n g toward d i s s o l v e d U4' i n the f u e l . A t the MSREs b e r y l l i u m m e t a l w a s dtssslved i n t h e f u e l s a l t p e r i o d i c a l l y in o r d e r to a d j u s t the redox p o t e n t i a l of the s a l t , and some changes i n the p h y s i c a l properties of t h e f u e l s a l t w e r e noted a t t h e s e t i m e s . Since such changes could a f f e c t t h e e f f i c i e n c y of t h e bubble g e n e r a t o r , f u r t h e r s t u d i e s of t h e v a r i a t i o n of p h y s i c a l p r o p e r t i e s of t h e salt w i t h redox p o t e n t i a l and t h e i r s i g n i f i c a n c e w i t h r e s p e c t t o xenon removal are needed t e r i a b inventory and system c o r r o s i o n pates w i l l b e i n d i c a t e d by a n a l y s i s s f the f u e l salt. On-line a n a l y t i c a l devices will be developed f o r t h i s a p p l i c a t i o n as o u t l i n e d i n S e c t i o n 6 . I n a d d i t i o n , i t will be n e c e s s a r y to p e r f o m s e l e c t e d c h e d c a l ELRalySeS i n a h o t cell l a b o r a t o r y . Obtaining a sample and d e l i v e r i n g i t to t h e l a b o r a t o r y requires careful manipulation to p r e v e n t altering the salt chemistry. In a d d i t i o n , adequate c o n t a i m e n t must be maintained. The experience w i t h the m m s m p $ e r , 7 which f u n c t i o n e d well d u r i n g the e n t i r e p e r i o d of o p e r a t i o n , will b e u t t l i z e d in developing smplers f o r future moltensalt reactors.

The a f t e r - h e a t removal system f o r t h e MSBR u t i l i z e s t h e f u e l d r a i n t a n k and a n a t u r a l - c i r c u l a t i o n NaK coolfng system. Heat is t r a n s f e r r e d from the s a l t t h r ~ ~ ganh a i r gap t o t u b e s t h r ~ u g hwhich NaK c i r c u l a t e s . The MSW d r a i n t a n k s W @ K ~ equipped with s i m i l a r s o s l i n g t u b e s having an a i r gap; however, b a i l i n g water w a s used as t h e c o o l i n g medim. The pred i c t e d heat transfer rates f o r t h i s system were v e r i f i e d ' b u t no information was. o b t a h e d on system service life.

10.3.2

Coolant s a l t technology development

A e x t u r e of LIF-BeF, (66-34 nole W > w a s used successful%y as the c o o l a n t in the secondary system o f t h e MSWE, b u t its high l i q u i d u s t e m p e r a t u r e (8?5'P) and h i g h cost ($600 t o $140a4/fta) prompted a s e a r c h for s t h e r p o s s i b l e c o o l a n t s . 2 7 Of t h e alternates c o n s i d e ~ e d ,the s o d i m f l u o r o b o r a t e e u t e c t i c , NaBPb-NaF (92-8 mole X I , appears t o b e the moat promising. It has a r e l a t i v e l y l o w m e l t i n g point (725°F) m d c o s t ($60/ft3),

lO-ll

and t h e r e i s a p o s s i b i l i t y t h a t i t can a i d i n p r e v e n t i n g t r a n s p o r t of t r i t i u m t o t h e s t e a m system by i n t e r a c t i o n w i t h t h e tritium. bong i t s d i s a d v a n t a g e s are (1) the need f o r BP3 i n t h e cover gas because of t h e e v o l u t i o n of BP3 from MaBFb a t MSBR o p e r a t i n g t e m p e r a t u r e s , and (2) t h e c o r r o s i v e n e s s of f l u o r o b o r a t e in t h e presence of w a t e r .

10.3.2.1

Experience

Sodium f l u o r o b o r a t e e u t e c t i c s a l t h a s been c i r c u l a t e d f o r t e n s o f thousands o f hours i n n a t u r a l - and forced-convection loops c o n s t r u c t e d of B a s t e l l o p N t o obtain d a t a on c o r r o s i o n , mass ~KEUIS~EX, and materials compatibilfty. I n a d d i t i o n , an PTSU-scale pump l o o p (PW-1) c o n s t r u c t e d of 4-ine-diam %neonel p i p e was o p e r a t e d w i t h a flow r a t e of 750 gpm a t $00 t o l800'F f o r over 11,000 h r t o obtain e x p e r i e n c e w i t h b o t h t h e s a l t and t h e BF3helium cover gas system r e q u i r e d for s a l t composition c o n t r o l . 2 8 Because t h e c o n f i g u r a t i o n of t h e PKP-P loop was not s u i t a b l e for conducting the a d d i t i o n a l r e q u i r e d experiments and t h e material of c o n s t r u c t i o n w a s a t y p i c a l C I ~c u r r e n t and proposed m o l t e n - s a l t r e a c t o r s , an all H a s t e l l a y N loop w a s designed and c o n s t r u c t e d u s i n g t h e pump and p i p i n g s a l v a g e d from t h e secondary c o o l a n t system of t h e MSRE. This l o o p , krto~nas t h e CoolantS a l t Technology F a c i l i t y (CSTF) s w a s undergoing shakedown t e s t s when t h e MSR Program w a s i n t e r r u p t e d i n 1972. Evidence of t h e c o r r o s i o n p r o d u c t , Na3CrP6, has been found i n v i r t u a l l y all loops c i r c u l a t i n g sodium f l u o r o b o r a t e . The c o r r o s i o n product i s found i n t h e c o l d e s t p a r e of t h e c i r c u i t and i s expected t o d e p o s i t on t u b e s i n t h e s t e a m - r a i s i n g equipment. For t h i s reason, t h e s o l u b i l i t y of Ma3CrF6 i n s o d i m f l u o r o b o r a t e was determined and cold trapping t e c h n i q u e s w e r e t e s t e d w i t h l h i t e d s u c c e s s for i s o l a t i n g t h i s material i n n a t u r a l - and f o r c e d - c i r c u l a t i o n l o o p s . Excessive d r a i n t i m e s have sometimes been encountered which w e r e a t t r i b u t e d to t h e accumulation of Na3CRFg i n d r a i n lines.

10.3.2.2

Status of fluoroborate coolant t e c k n d o g ~ ~

The c o m p a t i b i l i t y o f s o d i m f l u o r o b o r a t e w i t h t h e proposed MSBR. cont a i n e r material ( N a s t e l l o y N) i s s a t i s f a c t o r y ( c o r r o s i o n rate of 0.1 t o 0.2 m i l p e r year) provided t h a t m o i s t u r e i s excluded from the systern.29 ,&

H e a t t r a n s f e r d a t a o b t a i n e d w i t h t h e forced-convection loop FCL-2 are in good agreement w i t h t h e e m p i r i c a l c o r r e l a t i o n of S i e d e r and Tate. These d a t a i n d i c a t e t h a t sodium f l u o r s b o r a t e p e r f o m as a t y p i c a l h e a t transf e r fluid. 3o

~xgeriencew i t h o p e r a t i o n ~f the ~n-1 1 0 ~ ~ 2i n8d i c a t e s etaat the s a l t composition can b e monitored by r e l a t i n g t h e t h e m % c o n d u c t i v i t y of t h e off-gas to t h e t o t a l system p r e s s u r e and s a l t temperature, and t h e s a l t composition can b e c o n t r o l l e d by maintaining a s u i t a b l e BP3 p a r t i a l p r e s s u r e i n t h e gas above t h e s a l t i n t h e pump. *.&

...... :.... .:.x

10-12 ....

F l u o r o b o r a t e s a l t mist is a p o t e n t i a l l problem with t h e l a r g e pumps contemplated i n f u t u r e molten-salt reactors. Although sodium flaoroborate undergoes a s o l i d - p h a s e t r a n s i t i o n a t 'b470BF, no unusual problems assoc i a t e d w i t h t h i s phenomenon w e r e encountered w i t h o p e r a t i o n of t h e freeze V ~ V used ~ S in t h e fopced-eonvection anid PKP POOPS.

U s e of hydrogenous species in the c o o l a n t salt to control tritium m i g r a t i o n (see Task 4 . 3 . 4 of S e c t i o n 5 ) .

E f f e c t o f c 0 ~ 3 ~ 0 s i opnr o d ~ c t(Na3CrP6) d e p o s i t s on steam g e n e r a t o r p e - r f o r n ~ ~ cand e effectiveness of c o l d traps f o r ameliorating this problem.

E f f e c t of solid-phase d e n s i t y change on system p i p i n g and cornPClSlents (see Section 10 * $) *

F e a s i b i l i t y of a BFCJ r e c ~ v e r yand r e c y c l e system (see Section

10 7 6) e

Management of secondary circuit off-gas l i n e restrictions (see Section Ib8.9.6).

Variation of BF3 p a r t i a l p r e s s u r e d u r i n g g r o s s mixing sf f u e l and c o o l a n t salts.

10.3.3

S t e a w s y s t e m t e c h n o l s ~development

me salt-tO-Steaatt intelpface in ME.f%RSystem Will CoIlSist O f Steam genePa t o r s and steam r e h e a t e r s . The steam r e h e a t e r i s regarded as a convent i o n a l heat exchanger w i t h no fundamental p r o b l e m of heat t r a n s f e r o r development foreseen. Even though the 650°F reheat steam e n t e r s the r e h e a t e r below the 925°F Piquidus temperature of the eoobant s a l t , the $ow steam-side heat-transfer coefficient leads $0 the ~onclusionthat there will b e no significant problem w i t h f r e e z i n g of the s a l t . The steam g e n e r a t o r t u b e s w i l l contain s u p e r c r i t i c a l steam and, i n t h e reference d e s i g n , w i l l be i n c o n t a c t w i t h ~ Q ~ ~ Ufluoroborate. E I The peak temperature on t h e steam s i d e will b e about 100QoP and that on t h e s a l t s i d e will- b e 115Q"F. Both of t h e s e f l u i d s are c o r r o s i v e under c e r t a i n cdnditisns. S o d i m f l u o r o b o r a t e is a g g r e s s i v e i f t h e salt h a s been in c o n t a c t w i t h w a t e r , and steam i s o x i d i z i n g t o metals and can produce SesPeSS CSKrSSiSn C.b.ackiI'lg When it Contains Small C ! O n @ e I l t ~ E i t i O n § of &lorides. Thus, the material used f o r s t e a m g e n e r a t o r t u b e s in it mobtensalt system must resist c o r r o s i o n by b o t h sodium f l u o r o b o r a t e and steam, o r duplex t u b e s must be used.

310-13

t h e c o l d e r s u r f a c e s . The steam g e n e r a t o r d e s i g n must accsmodate t h e f r e e z i n g and thawing of t h i s small. amount of s a l t without s t r u c t u r a l damage t o t h e steam g e n e r a t o r .

It is l i k e l y t h a t d i r e c t maintenance of t h e steam g e n e r a t o r w i l l b e p o s s i b l e even though t h e r e w i l l b e some induced sodium a c t i v i t y i n the sodium f l u s r o b o r a t e . Estimates place t h e 24%jaa c t i v i t y a t a s u f f i c i e n t l y low value (about 1% 1-1 c u r i e s p e r gram of s a l t ) t o allow f o r d i r e c t maintenance i f t h e steam generator i s d r a i n e d of s a l t . Although the = t e n t sf t h e problem i s u n c e r t a i n at t h i s t i m e , it i s p o s s i b l e that t h e maintenance p l a n w i l l have t o accomodaee two o t h e r s o u r c e s of r a d i o a c t i v e contaminat i o n . Trace elements i n BastelEoy N (such as c o b a l t ) w i l l be a c t i v a t e d and could be s u b s e q u e n t l y d i s p e r s e d throughout the c o o l a n t c i r c u i t by the e o r r o s i o n p r o c e s s . F a i l u r e of a prTmaPy Pleat exchanger t u b e could allow f i s s i o n p r o d u c t s t o e n t e r t h e c o o l a n t and be d i s p e r s e d throughout t h e secondary c i r c u i t . The d e s i g n of the steam g e n e r a t o r must aceornod a t e the n e c e s s a r y maintenance and i n s p e c t i o n t o m e e t the requirements fog. i n - s e r v i c e i n s p e c t i o n , f o r minimizing d o n t i m e , and f o r d e t e c t i o n , l o s a t i o n , and plugging of l e a k i n g o r damaged stem t u b e s ( s e e S e c t i o n I1 f o r a discussion Of maintenance technology development). The stem-power system proposed f o r t h e MSBR r e f e r e n c e d e s i g n consists o f s u p e r c r i t i c a l cycle and equipment t h a t i s c o n v e n t i o n a l except f o r the feedwater and reheat s t e m p r e h e a t i n g f a c i l i t i e s . Tke c y d e used i n the B u l l Run s t e a m s t a t i o n of t h e TVA was adapted f o r use w i t h t h e MSBa h Order to TMke the p b m t G Q S t and p@rforItXXlc@eStiTtlat@sItlore r e a l i s t i c . The M B B s t e m c y c l e uses s t e m at t u r b i n e t h r o t t l e cocdit i o n s 0% 3568 p s i a and 1066°F. Steam g e n e r a t o r o u t l e t steam attemperat i o n i s provided f ~ f c- o n t r o l of t u r b i n e i n l e t c o n d i t i o n s a t p a r t - l o a d operation.

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One sf th@ two unconventiona% f e a t u r e s i n 0WLPs a d a p t a t t o n af t h e TVA steam cycle i s t h e two-stage r e h e a t of e x t r a c t i o n stem by use s f a prime-steam-heated preheater and a s a l t - h e a t e d r e h e a t e r . The a t h e r unconventisnal. feature i s t h e h e a t i n g of feedwater t o 700°F by d i r e c t . mixing of t h e 8 6 6 V s t e a m e x i t i n g the above prelreater with. t h e h i g h p r e s s u r e 550°F feedwater leE%vin t h e t o p extraetion h e a t e r . Two large XIIOtOh-dKiVEXI, Canned-rOtoK Cent i f u g a l pumps i n p a r a l l e l are used to b o o s t about P9,OQO gpm of feedwater from about 3500 p s i a t o 3806 p s i a . E i g h t steps of feedwater heating are used in a d d i t i o n to the direct f i x i n g s t e p t o obtain t h e 708°F feedw t e r temperature. The use sf the superc r i t i c a l c y c l e allows d i r e c t d x i n without s e r i o u s problems.

10-14

26 use of feedwater a t 580°F i s determined to b e f e a s i b l e , the mixing chamber, p r e s s u ~ eb o o s t e r pumps, and r e h e a t stem preheatem could b e e l i m i n a t e d from t h e s u p e r c r i t i c a l c y c l e . The i n c r e a s e in e f f i c i e n c y plus t h e s i m p l i f i c a t i o n of t h e steam system W O U ~r e~p r e s e n t a substant i a l s a v i n g s . A l t e r n a t i v e l y , a s u b c r i t i c a l p r e s s u r e steam cycle becomes f e a s i b l e and can be i n c l u d e d i n the options for a MSBR power system. me f e a s i b i l i t y of using Power feedwater temperature should be i n v e s t i gated for b o t h s u b c r i t i c a l and s u p e r c r i t i c a l p r e s s u r e steam cycles.

10.3.3.l

Experience

S i n c e mny s f t h e problems of m o l t e n - s a l t and l i q u i d - m e t a l systems are similar, the e x p e r i e n c e being gained i n t h e W B W program w i l l b e h e l p f u l i n p r o v i d i n g information which i s either d i r e c t l y a p p l i c a b l e o r at least s u f f i c i e n t l y s i m i l a r t o p r o v i d e guidance i n p l a n n i n g t h e development program. A few e ~ m p l e sof WflBW development areas i n which pKoblems are S i d l a r are ips fOllQWs2

1. Work done i n the development of high-temperature d e s i g n c r i t e r i a and theanal stress a n a l y s i s of complex geometries will b e a p p l i c a b l e although t h e materials are n o t t h e same. 2.

The problems of s t a b i l i t y and fluw r e v e r s a l at l o w l o a d ~n t h e t u b e and shell s i d e s r e s p e c t i v e l y are s i m i l a r t o those s f a m o l t e n - s a l t generator.

The problems of o v e r p r e s s u r e p r o t e c t i o n and p r e s s u r e p u l s e a n a l y s i s ~f the ~ e c ~ n d asystem ~y are similar and p ~ ~ t i o nof s the 19?IpBW exp e r i e n c e w i l l b e h e l p f u l i n planning the n o l t e n - s a l t tests.

The LMFBIW e x p e r i e n c e i n t h e development of t e c h n i q u e s for t h e f a b r i c a t i ~ no f t h i c k tube sheets and j o i n i n g of t u b e s t o t u b e sheets w i l l

b e sf b e n e f i t t o the m o l t e n - s a l t program.

The coolant s a l t composition used i n t h e MSRE is n o t t h e same as that p ~ o p ~ s ef do r t h e MSBR. However, p r e l i m i n a r y heat t r a n s f e r i n f ~ m t i ~ n o b t a i n e d d u r i n g operation of a small COKPQS~CXI loop w i t h sodium fluorob o r a t e i n d i c a t e s g e n e r a l agreement with the Sieder-Tate c o r r e l a t i o n , and i n d i c a t e s that the use of a c c u r a t e p h y s i c a l p r o p e r t y d a t a w i t h c o r r e l a t i o n s rased f o r noma1 f l u i d s i s adequate for h e a t t r a n s f e r d e s i g n i n f l ~ ~ ~ salt i d esystems. C o r r e l a t i o n s f o r h e a t transfer and pressure drop were chosen from t h e open l i t e r a t u r e and adapted f o r u s e i n d e s i g n i n g the MSBR refeKe€lCe priIllaPy h e a t @Xchang@Kand S t e m geneKatQr.

AP%hough t h e o p e r a t i n g e x p e r i e n c e w i t h salts i s q u i t e e x t e n s i v e 9 t h e r e has been no e x p e r i e n c e in the g e n e r a t i o n of stem i n high-temperature, molten-salt-heated steam g e n e r a t o r s . There i s a c o n s i d e r a b l e amount of e x p e r i e n c e , b o t h i n t h e USA and Europe, w i t h a low-melting s a l t (Hitec) for the g e n e r a t i o n of low-pressure stem and as a heat t r a n s f e r mc~ierm.~

k.2

lo-15

The c o m p a t i b i l i t y of H a s t e l l o y N w i t h steam h a s been i n v e s t i g a t e d i n a test f a c i l i t y i n t h e TVA Bull Bun Steam P l a n t . Unstressed specimens t h a t w e r e exposed t o stem a t lO00"P had very a c c e p t a b l e m e t a l l o s s rates (<O.25 m i l / y e a r ) . Work h a s been conducted t o e v a l u a t e t h e p o s s i b i l i t i e s of stress c o r r o s i o n of H a s t e l l o y M i n the presence of steam as r e p o r t e d by S p a l a p i s e t a1.9 based on t h e i r r a t h e r limited work. Some tests have been performed on duplex t u b i n g manufactured by t h e I n t e r n a t i o n a l Nickel Company which c o n s i s t e d of I n c s l o y 800 QII t h e steam s i d e ( i n s i d e ) and n i c k e l on t h e s a l t s i d e . I n t h i s arrangement, t h e s e materials have e x c e l l e n t c o m p a t i b i l i t y w i t h s a l t and stem.

A s p r e v i o u s l y mentioned, t h e unconventional feedwater h e a t i n g r e q u i r e ments of t h e KSBW r e f e r e n c e stem c y c l e r e q u i r e t h e u s e of b o o s t e r pumps and mixing chambers. Although b o t h of t h e s e components are c u r r e n t l y i n use a t c o n d i t i o n s n e a r t h o s e r e q u i r e d , t h e s i z e s needed f o r a lOOO--Mhr(e) E B B are n o t p r e s e n t l y a v a i l a b l e . While c a r r y i n g o u t work under an ORWE s u b c o n t r a c t , Ebasco S e r v i c e s , Pnc., found t h a t t h e canned-rotor b o o s t e r pumps needed f o r t h e MSBW steam c y c l e are about 50% l a r g e r t h a n t h e l a r g e s t known pump b u i l t t o d a t e . Consequently, development sf l a r g e r c a p a c i t y , m u l t i s t a g e pumps would be needed. The mixing chambers needed are a l s o l a r g e r t h a n t h o s e i n use, b u t t h i s does n o t appear t o i ~ n p ~ sae major development problem s i n c e a chamber s i m i l a r t o one s p e c i f i e d f o r t h e MSBR system and about f o u r - f i f t h s as l a r g e is i n use a t t h e TVA B u l l Run S t e a m P l a n t . A s an a l t e r n a t i v e , a high-pressure h e a t exchanger could b e used t o obt a i n t h e 700°F feedwater. The e x i t h e a t f n g steam could b e then h e a t e d t o 1000°F i n a s a l t - h e a t e d exchanger and r e i n t r o d u c e d i n t o t h e c y c l e , t h e r e b y e l i m i n a t i n g t h e p r e s s u r e b o o s t e r pumps.

.... X , &

..... ..

Working under OWL s u b c o n t r a c t , Ebasco S e r v i c e s , Inc., examined a l t e r n a t i v e stem s y s t e m b u t s e l e c t e d e s s e n t i a l l y t h e same stem system as t h e They concluded t h a t t h e use of d i r e c t d x i n g ORNL r e f e r e n c e system." f o r feedwater h e a t i n g and t h e s p e c i a l booster pumps i s f e a s i b l e and w i t h i n f o r e s e e a b l e t e c h n o l o g i c a l development. With t h e background of MSRE e x p e r i e n c e and t h e subsequent development o p e r a t i o n , t h e r e i s conf i d e n c e i n p r e d i c t i n g s a l t - s i d e heat t r a n s f e r c o e f f i c i e n t s i f a c c u r a t e p h y s i c a l p r o p e r t y d a t a are a v a i l a b l e . More t e s t i n g and o p e r a t i n g experience i s needed w i t h t h e r e f e r e n c e - d e s i g n s a l t compositions t o v e r i f y p r e s e n t i n f o r m a t i o n concerning p h y s i c a l p r o p e r t i e s , h e a t t r a n s f e r and p r e s s u r e drop, and t h e avoidance sf flow i n s t a b i l i t y and s t r a t i f f c a t i o n problems. The c o r r o s i o n e x p e r i e n c e w i t h H a s t e l l o y N i n stem is mostly favorabl'e;

I I O W ~ V ~ Kseveral , questions must b e resalved before a firm conclusion can .... , :<.a

,j*J

..... .... ... .-i

be reached. The duplex t u b i n g of n i ~ k e l - I n c s l ~ 800 y l o o k s pr~wising: t h e c o m p a t i b i l i t y i s e x c e l l e n t , and p r o d u c t i o n methods f o r t h e t u b i n g

have been developed s o t h a t a h i g h q u a l i t y product can b e o b t a i n e d a t a lower cost than Hastelloy N t u b i n g . On t h e o t h e r han 9 steam g e n e r a t o r f a b r i c a t i o n ~ ~ o u bl ed complicated by use of duplex t u b i n g .

Some w ~ r khas been done w i t h computer s i m u l a t i o n s s f t h e ~ ~ ~ a tsf r othe l MSBR system, as d i s c u s s e d i n S e c t i o n 12. The r e s u l t s i n d i c a t e d that i n ~ r d e - kto maintain both t h e primary salt and t h e c o o l a n t salt. c o l d l e g temperatures above their respective l i q u i d u s t e m p e r a t u r e s , e i t h e r of ~ W O C6d~1trQ% schemes would b e s a t i s f a c t o r y ; b o t h require a v a r i a b l e COolaRt s a l t flowe One c o n t r o l scheme would r e q u i r e a t t e r n p r a t i ~ nof o u t l e t s t e m b e f o r e i t reaches the t u r b i n e a d t h e second would reqtiire a cont r o l l e d bypass f l o w of coolant s a l t a r ~ u n dt h e primary heat exchanger. '1Phe atteanlperation of O U t P e t s t e m between the st@= geIkeratOP and the turbine i n t r o d u c e s some u n c e r t a i n t y in t u r b i n e p~otection,while t h e controlled bypass flow would require the development of a s a l t throttling valve, The problems o f attemperation w i l l be e x p l o r e d as part of t h e s t e m generator i n d u s t r i a l program. a t e s a l t v a l v e r e q u i r e m e n t s are Some work has been done a t OWE w i t h d i s c u s s e d l a t e r ( S e c t i o n l.Q.3.7). a h y b r i d eomputer t o i d e n t i f y a d d e f i n e v a r i o u s c o n t r o l and emergency kranSi@ntS Which W i l l b e h p 3 s e d O W heat eXChangePSL2 8 0 that t h e designer can effectively d e a l with them b~ either C C X I ~ ~ O Hsystem d e s i g n o r s t r u c t u r a l design, A s t e a m generator develspment r e p o r t h a s been p r e p a r e d l which papeseliats the b a s i s f o r t h e development of molten-salt-heated steam g e n e r a t o r s and associated a u x i l i a r i e s such as a s t a r t u p system and a secondary s a l t p r e s s u r e - r e l i e f system. T h i s r e p o r t reviews t h e UfFBR program experience i n areas which appear a p p l i c a b l e t o molten-salt steam g e n e r a t o r s . A l s o , a conceptual d e s i g n description has been p r e p a r e d f o r a 3-m Steam Generator Tube Test Stand (STTS) f o r t h e p r e l i m i n a r y development t e s t i n g of multitube assemblies.

Conceptual d e s i g n s of m o l t e n - s a l t primary h e a t exchangers and s t e m generators have been O K are b e i n g prepared by O W L , Ebases S e r v i c e s , Inc., P o s t e r wheeler corporation, and by Black and Veatch. The cunc e p t u a l d e s i g n b e i n g considered f o r the r e f e r e n c e MSBR s y s t e m by PostebWheeler under an o m s u b c o n t r a c t c o n s i s t s of an ''I,'' c~nfigurations i z e d at 4 8 3 MW f o r a s i n g l e - u ~ i t - p e ~ - c ~ o l a ~ t - ldesign. ~op The unit would contain 1032 t u b e s ( 3 / 4 i n . OD, 8.125 i n . wall), and would b e a b o u t E16 f t tall. Long flow ( i n s t e a d of c r o s s flow) i s b e i n g considered 01% t h e s h e l l S i d e t o avoid t h e high pK@%sUre drop Which r e s U % t s from attf3lTlpting t 0 meet c o n f l i c t i n g requirements of v i b r a t i o n and b a f f l e spacing. h e steam generator c o n f i g u r a t i o n which w i l l receive a t t e n t i o n i n f u t u r e

n s t u d i e s and has promise of alleviating t h e feedwafer t e m p e r a t u r e

.... m .x

10-l7

requirement u s e s t h e bayonet o r r e - e n t r a n t tube concept. Although i n vestigati~ns t h u s far i n d i c a t e t h a t the bayonet t u b e c o n f i g u r a t i o n i s mot p r a c t i c a l a t s u p e r c r i t i e d pressures because of t h e t h i c k tube w a l l r e q u i r e d , i t has d e f i n i t e possibilities f o r a s u b c r i t i c a l p r e s s u r e system.

18.3.4

Cover and off-gas system technology development

'$%le cover and off-gas systems f o r a moltem-salt r e a c t o r must (1) p r o t e c t the f u e l amd c o o l a ~ ts a l t s f r o m o x i d i z i n g atmospheres, and (2) p r o v i d e p o s i t i v e c ~ n t ~ i i n m e noft t h e r a d i o a c t i v e noble gases and daughters and any other r a d i o a c t i v e material which might be t r a n s f e r r e d from t h e fuel sys t e m . Pn the f u e l ~ f f - g a s system f o r t h e r e f e r e n c e d e s i g n MSBR,31 fission product gasess t o g e t h e r with helium carrier gas and e n t r a i n e d salt, are s t r i p p e d from t h e f u e l s y s t m by means of a gas separator and v e n t u r i . %e gas p a s s e s f i r s t through t h e f u e l - s a l t d r a i n t a n k (and, if n e c e s s a r y , a p a r t i c l e t r a p ) where e n t r a i n e d s a l t and n o n - v o l a t i l e f i s s i o n p r o d u c t s are removed, and then through a 47-hr charcoal-bed holdup system where 97% 0% the %He-135 i s permitted t o decay. The gas i s t h e n S p l i t i l l t o t w o streams, one of which ($82) i s r e t u r n e d t o the f u e l system v i a t h e bubble g e n e r a t o r . The o t h e r stream (28%) i s passed through a Isng-delay charcoalbed holdup system where a l l r a d i o a c t i v e gases except Kr-85 are allowed t o decay t o i n s i g n i f i c a n t l e v e l s , and through a cleanup system f o r removaP 0% gaseous fFssion p r o d u c t s and o t h e r contaminants. T h i s stream i s t h e n r e c y c l e d t o t h e primary system f o r re-use a s purge gas.. No r a d i o a c t i v e fission products are d i s c h a r g e d to t h e a t ~ ~ ~ ~ p h e r e .

.... ... .%,A

... .... ...... :.=

... .$%

Charcoal-bed holdup systems w e r e used t o t r e a t t h e f u e l system off-gas S ~ K ~ E E I E from the Homogeneous Reactor Test (HRT) and t h e Mslten-SaIt Reactor Expertangant (MSRE). A ~ s Q ,~ h a r c o a lbeds are c u r r e n t l y b e i n g used as streams i n s o l i d - f u e l r e a c t o r s and p r o c e s s i n g systems. The MSRE off-gas s y s t e m g e n e r a l l y o p e r a t e d s a t i s f a c t o r i l y except f o r occas i o n a l plugging of the off-gas l i n e s due p a r t l y to o r g a n i c material and p a r t l y t o e n t r a i n e d s a l t and n o n - v o l a t i l e fission prod~ets. The MSRE cover gas s u p p l y system used a titanium-sponge reactor and a mslecularsieve column for removal of trace q u a n t i t i e s of water and Q X J T from ~ ~ ~ t h e gas.

10.3.4.2

S t a t u s of cover and off-gas system t e c h n o l o g ~ ~

D y n d e a d s o r p t i o n c o e f f i c i e n t s have been measured f o r Kmf a d xe on e ~ ~ a r c o ain~ .the temperature range 25 to 1 6 0 " ~ 32 .

.:.&.... <b

.'..... ....> .>%.%.

10-18 C ~ m p t e r~ ~ Q ~ K E S Ihave E been developed and used f o r t h e c a l c u l a t i o n of c h a r c o a l bed temperature p r e f i % e s , p i p e s i z e s , and c h a r c o a l q u a n t i t i e s f o r both the EWT and t h e MSWE. However, t h e programs do n o t p r o v i d e an optimum d e s i g n , and a c e r t a i n amount of i t e ~ a t i o - wand i n t e r p r e t a t i o n is necessary D

The use of side-st~eam i o d i n e s t r i p p e r s has been s u g g e s t e d as a method f o r a i n i d z i n g the Xe-135 p o i s o ~ lf r a c t i o n i n t h e MSBR. This c ~ n c e p t vas n o t i n c l u d e d i n t h e r e f e r e n c e d e s i g n , b u t c o n c e p t u a l d e s i g n s t u d i e s w e r e c a r r i e d out i n s u f f i c i e n t d e t a i l t o i n d i c a t e t h a t t h e gas f l would ~ ~ be about 2 . 3 m 3 / s e c (4800 cfm) and that t h e g a s should contaln 1% HF t o change the redox p ~ t e n t i a lof the s a l t . If a d e c i s i o n w e r e made t o use iodine s t r i p p e r s , a d i f f e r e n t approach t o t h e d e s i g n of t h e o f f - g a s s y s t e m would b e r e q u i r e d ~ 2 - the n ~ h i g h gas f l o w would make t h e charcoalbed SaoHclup system i m p r a e t i c d e Mew or a d d i t i o n a l work i s needed i n t h e following areas:

d y n a i c a d s o r p t i o n c o e f f i c i e n t s for ICP ana xe on c h a ~ c o a ~ weed t o b e e x p e r i m e n t a l l y determined f o r t h e temperature range 100°C t o t h e h i g h e s t a n t i c i p a t e d o p e r a t i n g t e m p e r a t u r e , currently 250'C. Other c h a r c o a l - r e l a t e d q u e s t i o n s which need i n v e s t i g a t i o n are t k e m a l s t a b i l i t y , n a t u r e and q u a n t i t y of eharcoal o u t g a s s i n g a t e l e v a t e d t e m p e r a t u r e s , and e f f e c t of s o l i d s l o a d i n g on t h e adsOKptiOn C Q e f f i C i e n t .

P a r t i c l e t r a p s m y be needed t o p r e v e n t plugging of pipe Pines i n b o t h the f u e l and C S O ~ ~ I - sI ~a l t off-gas system. Additional work i s needed t o e n a b l e prediction of the c h a r a c t e r and q u a n t i t y of e n t r a i n e d s o l i d s and e s t a b l i s h m e n t 0% c r i t e r i a fQh. t h e design of particle traps I

10.3.5

S a l t pump development

The p m p s f o r m o l t e n - s a l t b r e e d e r r e a c t o r s must c i r c u l a t e f l u o r i d e s a l t s in p r i m a r y ( f u e l ) and secondary ( c o o l a n t ) s a l t system r e l i a b l y a t temperatures as h i g h as 1300°F. E l e ~ t ~ ~ m a g n eand t i c c e n t r i f u g a l pumps have been considered f o r t h i s a p p l i c a t i o n . The low e l e c t r i c a l c o n d u c t i v i t y of molten f l u o r i d e s a l t s h i n d e r s the a p p l i c a t i o n of e l e c t r o m a g n e t i c pumps, and, consequently, t h e y are n o t used i n f l u o r i d e salt. s y s t e m . I n C Q ~ trast c e n t r i f u g a l p m p s have been applied very s a t i s f a c t o r i l y . A s t u d y 1 of the problems of a p p l y i n g t h e canned-rotor motor and the s h o r t - s h a f t and l o n g - s h a f t c o n f i g u r a t i o n s of the c e n t r i f u g a l pump t o molten-salt SeKViCe Wa8 m d e in 1967. me CEUIIK?d-KOtOr pUlTIp Was CQnCluded to be a very d e s i r a b l e c o n f i g u r a t i o n , s i n c e t h e r e are no o r i e n t a t i o n o r elevat i o n l i m i t a t i o n s on i t s a p p l i e a t i s n . However, it would require d i f f i c u l t and eXpenSiv62 dt3Velop~ent t o pKoVide pkflnpS f o r ED3 mBB Elpplfcation, including t h e develspmf2nt of a high-temperature e l e c t r i c motor having e l e c t 9 i C d i n S U l a t i Q n t h a t has a V@sty h i g h kesistance to IsUChX3.p radiat i o n damage. Thus e f f o r t s have been c e n t e r e d on sump pumps, and all pumps b u i l t o r p r ~ p o s e dfor FSBR's are c e n t r i f u g a l sump pumps.

10-19

This pump can b e considered t o have two b a s i c c o n f i g u r a t i o n s t h a t are d i f f e r e n t i a t e d by s h a f t l e n g t h and type of shaft s u p p o r t b e a r i n g s . The s h o r t - s h a f t pump has a r o t a r y element which c o n t a i n s c o n v e n t i o n a l , o i l l u b r i c a t e d b e a r i n g s t h a t s u p p o r t t h e s h a f t from which t h e impeller i s overhung. In t h e long-shaft pump t h e lower end of t h e s h a f t i s supported by a m o l t e n - % a l t - l u b r i c a t e d b e a r i n g . This type of p ~ r pmight b e p r e f e r a b l e f o r r e a c t o r s a l t systems t h a t r e q u i r e l o c a t i n g the i m p e l l e r a t r e l a t i v e l y low e l e v a t i o n s i n t h e system l a y o u t . A l l s a l t pumps built f o r test f a c i l i t y and r e a c t o r o p e r a t i o n a t Q%PN% have been of t h e s h o r t - s h a f t c o n f i g u r a t i o n , and t h i s pump t y p e i s proposed f o r t h e primary s a l t system i n t h e ~ e f e r e ~ cd e s i g n f o r a s i n g ~ ef l u i d S B W . ~ ~ Except f o r i t s l a r g e r c a p a c i t y , t h i s pump is very s i m i l a r t o t h o s e used i n E954 i n the ARE3 chose proposed f o r t h e A i r c r a f t Reactor T e s t (ART) i n t h e l a t e 1 9 5 0 ' ~ , ' and ~ those o p e r a t e d f o r o v e r 20,000 hours i n t h e MSRE in t h e 1960's. E f f o r t s w e r e made t o e l i c i t i n d u s t r i a l i n t e r e s t i n t h e p r o d u c t i o n of s a l t pumps f o r the AN?,, ART, MSIRE, and a s s o c i a t e d molten-salt t e s t f a c i l i t i e s . However, t h e number of pumps t o be produced a t any one t i m e w a s a p p a r e n t l y t o o s m a l l t o o b t a i n s e r i o u s i n d u s t r i a l ~ r 1969, i a s p e c i f i c a t i o n 1 8 w a s w r i t t e n f o r a s h o r t - s h a f t ceninterest. t r i f u g a l pump ts p r o v i d e t h e requirements of t h e primary and secondary s a l t systems in a 108- t o 208-Mw(t) MSBE. Westinghouse E l e c t r o Mechanical D i v i s i o n responded f a v o r a b l y t o t h e r e q u e s t , b u t clue t o t h e deemphasis s f the MSBR i n 1970 t h e i r p r o p o s a l w a s dropped.

Although t h e long-shaft c e n t r i f u g a l pump having s a l t - l u b r i c a t e d b e a r i n g s h a s been p r o p ~ s e das an a l t e r n a t e t o t h e s k o r t - s h a f t pump, e x p e r i e n c e w i t h m o l t e n - s a l t - l u b r i c a t e d b e a r i n g s i s very l i m i t e d . T e s t b e a r i n g s were o p e r a t e d a t OWL i n 1960, and a P a model pump w a s modified i n 1962 and o p e r a t e d f o r approximately 12,508 hr a t 1225°F w i t h t h e lower end of t h e s h a f t supported w i t h a E8Blten-salt-Pubricated b e a r i n g . Because large-scale pumps sf t h i s c o n f i g u r a t i o n were o u t s i d e known. e x p e r i ence, OWL had t h e r o t o r dynamics of t h e shaft-bearing-housBng system and t h e c h a r a c t e r i s t i c s of f n ~ a t e n - s a l t - l ~ ~ r i ~ abteeadr i n g s examined i n s o m e d e t a i l by Mechanical Technology Pnc. l 9 T h i s s t u d y d e f i n e d many of t h e remaining problems and produced recommendations f o r a development program.

...

The o p e r a t i o n of t h e M%RE r e p r e s e n t s t h e most-recent l a r g e - s c a l e e x p e r i ence w i t h s a l t - t o - s a l t h e a t exchangers 2 o This o p e r a t i o n provided a c o n s i d e r a b l e mount: of confidence i n t h e d e s i g n techniques and i n pred i c t e d performance i n f o r m a t i o n . e

.;.... .

.X&

...,. .!.X<>

>.:.= ...,:

..... ...... i

The h e a t t r a n s f e r c o r r e l a t i o n s used f o r t h e MSRE p r i r i - ~ i ~hye a t exchanger were based on t h e p r e v i o u s development tests which showed t h a t f l u o r i d e s a l t s behave as noma1 f l u i d s . When t h e MSRE o p e r a t i o n r e v e a l e d t h e overall heat transfer coefficient to be less than predicted, a reevaluation of t h e p h y s i c a l p r o p e r t i e s d i s c l o s e d t h a t t h e a c t u a l thermal eond u c t i v i t f e s of t h e f u e l a d c o o l a n t s a l t s were below t h o s e used i n t h e d e s i g n c a l c u l a t i o n s a d accounted €OK t h e d i f f e r e n c e . 2 1 me o v e r a l l heat

18-20

t r a n s f e r c o e f f i c i e n t of the MSRE h e a t exchanger dFd not change d u r i n g some 22,688 Bar s f salt c i r c u l a t i o n and 13,080 e q u i v a l e n t full-power hours O f OpePatioat, t h u s indicating EpB b u i l d u p Sf Scale and R o eVideRC.e O f gas filming. The f u e l - and c o o l a n t - s a l t compositions used i n t h e PISRE are n o t the same as those proposed f o r t h e XSBR. However, some p r e l i m i n a r y heat t r a n s f e r i n f o m a t i o n from t h e operation of a s m a l l corrosion kosp with sodium f l u o m b o r a t e i n d i c a t e s g e n e r a l agreement w i t h t h e S i e d e r - T a t e correlat i ~ n . ' ~~ h~u s , the use of a c c u r a t e physical p r o p e r t y data w i t h c o r r e l a tions f o r n o m a 1 f l u i d s is adequate OX- h e a t t r a n s f e r d e s i g n with f l u o r i d e s a l t s . There i s , however, no m o l t e n - s a l t heat t r a n s f e r e x p e r i e n c e w i t h t h e knurled t u b e s proposed f o r the primary h e a t exchanger i n t h e QRKL r e f e r e n c e design, nor i s information a v a i l a b l e on t h e e f f e c t s of sodium f l u s r o b o r a t e c o r r o s i o n product d e p o s i t i o n ora the t u b e s a

The volume of f u e l salt i n t h e h e a t exchanger must b e k e p t as low as practical to minimize t h e fuel d o u b l i n g time f o r t h e reactor.

%e e n t r a n c e and e x i t salt t e m p e r a t u r ~ ~p,r e s s u r e d r o p s , and the t o t a l h e a t t r a n s f e r capacity must e s n f o m w i t h the o v e r a l l system operating conditions.

The t y p e of h e a t exchanger, g e n e r a l Iscatian of Ipozz%es, h e i g h t of t h e w i t , and minimum t u b e diameter must be compatible w i t h v a r i o u s d e s i g n , Payout, and f a b r i c a t i o n c o n s i d e r a t i o n s .

The heat exchanger must b e arranged for r e l a t i v e l y easy tube-bundle replacement by means ~f remotely o p e r a t e d t o o l i n g .

Flaw v e l o c i t i e s , b a f f l e t h i c k n e s s , t u b e c l e a r a n c e , and b a f f l e s p a c i n g s h o u l d b e selected t o minimize p o s s i b i l i t i e s of v i b r a t i o n .

Within t h e framework of the above requirements and g u i d e l i n e s , d e s i g n procedures23 ~ R C Ia computer prsgram2' w e r e developed t o produce an e f f i c i e n t h e a t exchanger d e s i g n having a low f u e l - s a l t VQEImE?.

10.3.7

Valve development

Valves will b e r e q u i r e d i n m o l t e n - s a l t r e a c t o r s f o r i s o l a t i n g portions O f the r e a c t o r w h i l e t h e remainder operates, d i r e c t i n g flow to alternate

p...

10-21.

Five 4-in. t h l - o t t l i n g valves were designed and f a b r i c a t e d at ORNL a r ~ ~ n e t 1955 f o r f l o w c o n t r s l i n five pump Esops that o p e r a t e d w i t h molten salts and liquid m e t a l s . The valves w e r e designed f o r throttling service o n l y and w e r e f a b r i c a t e d of Inconel. They w e r e operated f o r a t o t a l t h e of l l L 5 , O O Q hr at temperatures ranging f r o m 1068 t o 1506"P, and no b e l l o w s failure or s i g n i f i c a n t mechanical problems occurred d u r i n g that time. T e s t s sf bell~ws-sealedmechanical valves w e r e conducted around 1957 i n t h e A i r c r a f t Nuclear Propulsisam Program i n an a t t e m p t t o develop a 1-l/2--in. shut-off valve f a r molten s a l t a t temperatures of 1.200 t o l58O"F. 'Fl%evalve seat material w a s considered t o b e t h e and a l t h o u g h a successful valve was n o t CL~~elopedi prior to cancellation Of t h e W Q F k , pf-OmiSi€Ig Seat and p l u g EBtel-ial C O d h L 3 t i O l E i W e K e $nVestigated. Bello~s-seaPed valves UP to a f e w inches in size have been used SucCessfully in ntany SOdhH1 appli@ationse Most SodiLKil V d V e s of larger s i z e , however, have had sodium f r e e z e seals on the valve stem, and t h i s option i s n o t available f o r molten-salt valves. However, t h e valve desigm, f a b r i c a t i o n , and s p e r a t i o n p r e s e n t l y planned i n the W B R prog~am s h o u ~p r o v ~ d er n u c ~useful ~ i n f o m a t i o n to ms~ten-sait valve develop-

ment *

Tfae d e s i g n Q% the MSBR takes advantage of the ease of adding E u d while t h e reactor is o p e r a t i n g to minimize the excess reactivity in t h e core,

and the a b i l i t y t o drain the f u e l to e f f e c t complete ~EXX%OK shutdown. C O l l t r O l rod8 Which have both regUlathg and Shi&Ilg fPlnCtiolnS and safety rods used primarily f o r r e a c t o r shutdown are included i n t h e reference design. The C Q I I ~ X - Q r~ o d s are g r a p h i t e c y l i n d e r s operating directly 2.n the salt. The s a f e t y rods are boron c a r b i d e (clad in Hastehloy N) and a l s o operate d i r e c t l y in the s a l t . HQWWer,

The controf and s a f e t y r o d s of the ARE and MSRE were o p e r a t e d in metal les that s e p a r a t e d t h e m from the salt and t h e r e f o r e ~ e q ~ i r eadm i l i a q gas ccaolsbng. Beeanse the r o d s and d r i - ~ e swere s e p a r a t e d from t h e s a l t t h e r e was no probllem of gas seals fop fission product c o n t r o l .

10-22

and sintered into a rider of s h o r t cylindrical tubes which w e r e in turn canned in Inconel. Visual observation 0% some s f the canned elements at the end of the reactor operation revealed no significant changes in dimensions o r external appearance. There has been no experience with C Q I - I ~ K ~rods P o p e r a t e d directly in the salt; however, the physical arrangement and provisions for c ~ o l i n gmight be similar t o that in the liquid-metal-cooled reactors. In one p r o p o s a l for a c o n t r o l r o d f o r use with a liquid-metal-cooled reactor, the poison seetfon is guided within a duct which i s positioned within the core. The MSBR reference design uses graphite ducts f o r uiding the safety rods and the graphite control r o d s . The materials proposed f o r the poison elements f o r the MSBR are similar to those used in the ARE. There is wide mperience with fo.b-naing raree a r t h oxides and B4C i n t o usable shapes and canning the elements to protect them from the environment. Experience is lacking with such elements in a high neutron %Emf i e l d ; however, work is in pia%og?pess w i t h i n the LWBR Prsgran. 10.3.9

Containment and c e l l heating development

The molten-salt react~rplant differs f r o m o t h e r reactor plants in that large aIlloU?3ts Sf f i . S S $ O l l products are dkp@%S@d thToPaghQut the K e a C t C l r primary system and several auxiliary systems. To alleviate the p ~ s s f b i l i t y of escape of radioactivity, double containment is provided f o r equipment that contains the bulk of the radioactive liquids and gases, For secondary containment, the general design for an MSBR can f o l l o w the that has come t o b e rather standard f o r nuclear reactors, and no I construction techniques seem to be involved i n b u i l d i f l g the Cylindrical s h e l l . ShCe IIlUCh Of the ec/UipmE?l-rt and pipi% COYltaiEl fuel salt, heating must be supplied to preheat and maintain it a t 160O'F or higher. The MSBW primary system design calls f o r using the reactor and fuel drain tank c e l l s as ovens for preheating the equipment and piping. The "El?p r h a ? p y containment concept is very similar to t h i s , with comparable temperatures and much higher design pressuress and erience gained with supportin heavy equipment in % h i s enviroment and with cell waH1 cooling should provide much useful infomation and guidance*

EO 4.1 0

.... wi.

Objective

'%he objective of this task roup is t o develop the t chnology associated with the f u e l salt system at is necessary f o r desi n of the primary circuit of a molten-salt test reactor and for confident scale up t o a moaten-salt d m o n s t r a t i o n reactor.

I ,

16-23

10.4.2

Schedule

As i n d i c a t e d i n Table 1 8 . 4 . 2 , c o n a t r u c t a o n of t h e Gas-Systems TechnoPogy F a c i l i t y will b e completed for water o p e r a t i o n i n I T 1975, and t h e water tests w i l l b e c a r r i e d o u t . I n 1976, m o d i f i c a t i o n of the GSTF f o r salt o p e ~ a t f o nw i l l b e completed, f a c i l i t y shakedown w i l l b e done, and t e s t o p e r a t i o n w i l l b e s t a r t e d . The primary emphasis w i l l b e on e v a l u a t i n g the p e r f o r m n e e of t h e bubble generator-bubble s e p a r a t o r . I n FY 1977, t e s t i n g of t h e bubble generator-bubble s e p a r a t o r w i l l c o n t i n u e b u t the emphasis will. s w i t c h t o o t h e r tests such as t r i t i u m t r a n s p o r t s t u d i e s , s a l t chemistry s t u d i e s , and mass t r a n s f e r measurements.

Tke work i n PY 1 9 7 6 and 1977 w i l l b e d i r e c t e d toward o b t a i n i n g g e n e r a l i n f o r m a t i o n in a l l problem areas r e l a t e d to f u e l salt system technology r a t h e r than refining t h e d a t a Tn one s p e c i f i c area. With t h i s approach, t h e s e s h ~ u l db e no overall u n c e r t a i n t i e s concerning the f u e l s a l t system, and refinement of d a t a can be aeiayea until about m 1980.

The remainder of t h e development work i n t h e Gas-Systems Technology F a c i l i t y s h o u l d b e completed d u r i n g EY 1981, as web1 as s t u d i e s f o r e v a l u a t i o n of xenon removal. The remainder of t h e known development work i n t h i s t a s k group can be f i n i s h e d by ET 1984.

18.4 3

Funding

The o p e r a t i n g fund requirements for this t a s k group are summarized i n T a b l e 10.4.3.1. C a p i t a l equipment funds f o r t h i s t a s k group are shown i n Table 1 0 . 4 . 3 . 2 .

10.4.4

,.&

....s ,

....

;&j

Facilities

Most of t h e e a r l y work a s s o c i a t e d w i t h t h i s t a s k group w i l l b e done i n t h e Gas-System Technology F a c i l i t y (GSTP) a f a c i l i t y f o r c i r c u l a t i n g molten s a l t a t a p p r o x h a t e l y IQOQ gpm over t h e temperature range of 566 to 704°C: (1050 t o l300V). The s a l t t o b e used d u r i n g mst of the system ope ratio^^ w i l l b e of t h e same composition as t h e f u e l s a l t proposed ~ O K an mBR. F i g u r e 10.4.4 i s a s h p l i f i e d diagram of the main systems of the f a c i l i t y . The s a l t c i r c u l a t i n g system c o n s i s t s of a modified MSRE MAaK E1 pump and two parallel p i p e l o o p s . The main Poop c o n t a i n s a f l o w measuring, v e n t u r i , a bubble s e p a r a t o r , a flow restrictsr, amd a bubble g e n e r a t o r . The supply and discharge from t h e s a l t pump c ~ n t a isupply ~ and r e t u r n conn e c t i o n s f o r f u t u r e auxiliary h o p s . The loop p i p i n g and the b u l k - s a l t s e p a r a t o r are f a b r i c a t e d f r o m 5-in. H a s t e l l o y N pipe. M e t a l l u r g i c a l s u r v e i l l a n c e specimens are i n s t a l l e d i n t h e main loop to a b h w p e r i o d i c '

checks on the externt of esrrcssion of the system.

Pbscal 1977

1976

..^

19 79

year

1980

Table

9.1.1

10.4.3.1.

Qperatfng

fund requirements (ctxts

GSTF water tests 9.1.B.1 Pump and flow restrietaar 9.1.1,2 Bubble generator-bubble separator

for Task Group 9.1 - Fuel in lMN3 lollare;)

salt

Fiscal

year

technology

development

92 20 112

9.1.2

GSTF salt studies 9.1.2.1 $ubbPe generator-bubble separator 9.1.2.2 Tritfum transport 9.1.2.3 Salt c.bemistry 9.1.2.4 Mass transfer 9.1.2.5 Meat transfer 9.1.2.6 Materials studies 9.1.2.7 salt jets Subtotal

9.1.2

l7Q 218 38

8Q 50 40 58

5Q 50 30

20 IQ

2x2

230

160

50 33

m 10 5Q 2QQ

9.%.3

After

heat

removal

9.1.4

Salt

sampler

9.1.5

Xensn removal

evaPuation

Total

operating

for

250

funds

Task Group 9.1

----440

288

a50

250

2QQ

9.1.2.1

Hiscellaneo~

9.1.2.1

Rmp ~0tax-y element

9.1.3

Test

Total

capftd

stand

for

equipment

imtrtnrents

afterheat funds

and equipment

1975

1976

la;

1977

1978

Fiscaa

yemr

1979

198Q

1981

1gm

1983

58 studies fop Task Group 9.1

50 5Q

1$84 P E

ORML-DWG

74-13437R

STACK

BLOWER SAMPLER ENCLOSURE

INSTRUMENT PENETRATIONS VlEWlMG PORTS Y

SALT

PUMP

STACK

Fig.

10.4.4,

GSTP

schematic.

18-28

A s m a l l stream of s a l t i s d i v e r t e d t o a s a l t - m o n i t o r i n g vessel which h a s p ~ ~ v i s i o f~olrs i n s e r t i n g probes f o r o n - l i n e monitoring of t h e chemical composition sf t h e s a l t . Samples of t h e s a l t can b e removed from t h e s a l t - m o n i t o r i n g vessel, the s a l t pump, o r the d r a i n tank. The d r a i n tank i s s e p a r a t e d from t h e l o o p by a f r e e z e v a l v e i n t h e connecting s a l t line D

A l l s a l t - c o n t a i n i n g components are h e a t e d w i t h e l e c t r i c a l h e a t e r s which are capable of h o l d i n g t h e component temperatures as high as 784°C (1300°F)

Helium i s s u p p l i e d t o t h e loop by t h e cover-gas system which c o n t a i n s d r y e r s and oxygen-removal u n i t s . The l a r g e s t flow of gas i s t o the bubble g e n e r a t o r with smaller flows t o t h e s a l t p m p s h a f t and t o t h e bubblertype l e v e l elements. 'Pke combined off-gas stream f l o w s through a holdup volume and a p r e s s u r e - t h r o t t l i n g valve t o s i m u l a t e t h e MSBR off-gas .Sy-stelR.

In normal o p e r a t i o n t h e gas s p a c e i n t h e s a l t pump o p e r a t e s a t a p r e s s u r e of 15 p i g . The pump h a s a r a t e d f l o w of 1000 g p m a t a d i s c h a r g e p r e s s u r e of 156 p s i g . The s a l t flow through t h e main loop is 500 gpm. G a s can b e i n j e c t e d into t h e bubble g e n e r a t o r a t flow rates as h i g h as 37 s e d . l i t e r s / mias and i s removed a t t h e b u b b l e s e p a r a t o r along w i t h an accompanying s a l t f l o w ranging from I1 t o 9 . 5 gpm. Almost a l l of t h e salt i s s e p a r a t e d from t h e gas i n t h e b u l k - s a l t s e p a r a t o r and r e t u r n e d t o t h e salt pump. The gas fHows t o t h e d r a i n t a n k where it combines w i t h t h e o t h e r gas flows. The as from t h e d r a i n t a n k i s e i t h e r d i s c a r d e d t o t h e s t a c k o r r e c y c l e d ts the bubble g e n e r a t o r . The bubble f r a c t i o n i n t h e loop i s measured by a g a m a d e n s i t o m e t e r downstream of t h e bubble s e p a r a t o r . The s a l t and gas f l o w rates which can b e o b t a i n e d in t h e GSTP are e q u a l t o t h o s e a n t i c i p a t e d i n t h e xenon removal s i d e stream of a 150-mCt) PER, and allow f o r l a r g e scale t e s t i n g of mimy a s p e c t s of the xenon removal system. Other work r e l a t e d to t h e f u e l s a l t system w i l l b e c a r r i e d o u t i n i n d f v i d u a l f a c i l i t i e s o r i n t h e Componetnt~T e s t Facility ( s e e S e c t i o n 18.13).

lQ.4.5 A f t e r c o n s t r u c t i o n of t h e f a c i l i t y hats been completed, components and systems w i l l b e t e s t e d . In a d d i t i o n , t h e s a l t system w i l l b e o p e r a t e d w i t h water t o determine t h e system o p e r a t i n g c h a r a c t e r i s t i c s and t o test v a r i o u s components such as t h e b u b b l e generator-bubble s e p a r a t o r .

10.4.5.1

Subtask 9 . P . l . l res t r i c t o r s

T e s t of t h e s a l t p m p and v a r i a b l e f l o w

The s a l t pump b e i n g used i s a KSFS NARK 11 pump which has been modified t o o b t a i n c h a r a c t e r i s t i c s similar t o t h e MSBR p m p by a l t e r i n g t h e pump i n l e t and volute. Since confidence i n t h e c a l c u l a t i o n s for wis-matched i m p e l l e r s and volute is not adequate, t h e h y d r a u l i c perfomanee of t h e

16-29 p m p will b e tested d u r i n g the first s t a g e of the water runs. The s h a f t deflection will a l s o be measured d u r i n g this p e r i o d . Based OR t h i s i n f o r mation, the f i n a l pump modifications will b e made ineluding sizing of the Impeller. The pump am$ variable f l o w r e s t r i c t o r s w i l l then b e c a l i b r a t e d .

The t i m e and o p e r a t i n g funds r e q u i r e d f o r c ~ r n p l e t of i~~ facility ~ c~ns t r u s t i o n and shakedown are i n c l u d e d i n this subtask.

10.4.5.2

Subtask 9.1.1.2

Tests of the bubble generator-bubble s e p a r a t o r

Helium will b e injected i n t o the water through t h e bubble g e n e r a t o r and rgnrtsvecl a t the bubble s e p a r a t o r a t f l o w rates i n the range of t h o s e a n t f c i p a t e d for s a l t o p e r ~ i t i ~ n .The efficiency of the bubble s e p a r a t o r f o r gas removal w i l l b e determined, using the measured b u b b l e f r a c t i o n d o m s t r e m of t h e bubble s e p a r a t o r and the gas flow r a t e to the bubble generator.

,.&

18.4,6

After modificatisns have been made t o t h e facility t o a l l o w salt operation, the performance sf t h e bubble enerator and bubble separator w i l l b e evaluated Using s a l t Under V a l f i Q U S o p e r a t i n g conditions. n e e f f e c t s of salt redox p o t e n t i a l on bubble g ~ ~ ~ r a t ~ ~ - b a i 8 ssebplaer a t o r pe f o m n c e w i l l b e determined, If necessary$ modifications t o the bubble enerator o r bubble separator will b e made as the work progresses.

A*;:

c...,u

The time and funds s p e n t modifying the system f o r salt o p e r a t i o n , addition of s a l t , and shakedown are included in this subtask.

:..... :-

%0.4,6.2

...

;a ..I

... ....

,.>=

... .... ::*>

Subtask 9.1.2.2

Tritium transport studies

10-30

A number 0% s t u d i e s r e l a t e d t o s a l t chemistry a r e of i n t e r e s t , and the need f o r others may become a p p a r e n t as work p r o g r e s s e s . One series of experiments w i l l be perf~b-11~8 for determining the r e l a t i o n s h i p between U4+/Y4* ratio and s a l t s u r f a c e t e n s i o n . This work i s motivated by the o b s e r v a t i o n s i n t h e PISRE of lowered s a l t surface tension a f t e r adjustment of redox p o t e n t i a l by t h e a d d i t i o n of m e t a l l i c b e r y l l i u m t o the fuel s a l t , and by q u e s t i o n s r e l a t i n g t o t h e effect of redox p o t e n t i a l on xenon removal. e f f i c i e n c y .

a...

The r o l e sf non-wetted metal p a r t i c u l a t e s , and t h e i r r e l a t i o n t o bubble behavior a l s o needs further s t u d y . P ~ o v i s i o n sw i l l b e made, if p o s s i b l e , f o r c a r e f u l e v a l u a t i o n of gas-borne s p e c i e s i n terns of p a r t i c l e s i z e d i s t r i b u t i o n and composition of p a r t i c u l a t e s and g a s p as a f u n c t i o n of the c o n t r o l l e d chemical and o p e r a t i o n a l parameters. Sodium f l u s r o b o r a t e i n j e c t i o n , d e t e c t i o n and emo oval from f u e l s a l t w i l l also be investigated.

The m a s s transfer c o e f f i c i e n t between a gas dissolved i n a l i q u i d and a gas bubble i s i n general. a f u n c t i o n of t h e Schmidt and Reynolds moduli.

The parameters varied i n w a t e r tests to d a t e have been v e l o c i t y , p i p e diameter, and kinematic v i s c o s P t y ; and s i n c e the tests were b o t h isothermal and i s o b a r i c , the d i f f u s i o n . c o e f f i c i e n t in t h e Schmidt modulus w a s a cons t a n t . The bubble size must a l s o b e k n m t o determine t h e mass transfer c o e f f i c i e n t uniquely from t h e concentration-versus-time d a t a taken in t h e w a t e r tests. Until the advent of suitable i n s t r u m e n t a t i o n f o r determining bubble s i z e in a high-temperature c i r c u l a t i n g s a l t , and i n the absence of knowledge about molecular d i f f u s i o n of gases through s a l t , mass t r a n s erimentation will be limited t o a d e t e r m i n a t i o n of t h e p r o d u c t of the mass t r a n s f e r c o e f f i c i e n t and the e f f e c t i v e bubble s u r f a c e area. ~ b t h s u g h t h i s aoes n o t pernit a general correlation, such i n f o r m t i o n would be u s e f u l i n c o n j u n c t i o n with data f r o m t h e bubble g e n e r a t o r tests under the s a m e c o n d i t i ~ ~0% s s a l t f l o w , c h e m i s t r y , t e m p e r a t u r e and s t r i p p e r ~. gas v o i d f r a ~ t i o ~ Measurements will be made of d i s s o l v e d noble gas ( p o s s i b l y u s i n g a r a d i o a c t i v e t r a c e r ) as a function of t i m e under various c o n d i t i o n s of salt flow rates, temperature, chemistry, and s t r i p p e r gas void f r a c t i o n . VariatFom of test seetion diameter and o r i e n t a t i o n m y a l s o b e included.

10.4.6.5

Subtask 9.1.2.5

Beat t r a n s f e r tests

To d a t e , h e a t - t r a n s f e r tests with MSBR fuel s a l t have involved once-through t e a t s e c t i o n s without t h e p r e s e n c e of gas b u b b l e s . me Gas-System TechF a c i l i t y a l l o w s n o t only the c o r r o b o r a t i o n of previo~sd a t a b u t also the d e t e r m i n a t i o n of the e f f e c t of v a r i o u s gas void f r a c t i o n s on t h e heattransfe~c o e f f i c i e n t s , b o t h in fully-developed f l o w and in regions where

10-31

boundary layers are developing. A r e s i s t a n c e - h e a t e d t u b e , p s s s t b % y similar to t h e proposed primary heat-exchanger t u b e s , w i l l b e connected a c r o s s two of t h e capped p i p e s t u b s provided. The v a r i a t i o n of h e a t f l u x w i t h R ~ ~ R c J P ~ s modulus w i l l b e measured over t h e range of v a l u e s expected i n t h e MSBR c o r e and h e a t exchanger.

P0.4.6.6

Subtask 9 . 1 . 2 . 6

Materials s t u d i e s

Most of t h e materials development work f o r m o l t e n - s a l t r e a c t o r s i s covered i n S e c t i o n s 2 , 4 , and 9. This s u b t a s k covers work f o r determining cornp a t i b i l i t y of materials w i t h f u e l s a l t under o p e r a t i n g c o n d i t i o n s . Specimens w i l l b e exposed t o flowing s a l t streams and s i d e l o o p s t u d i e s will be made u s i n g p o t e n t i a l materials of c o n s t r u c t i o n .

10.4.6.7

Subtask 9 . 1 . 2 . 7

S a l t j e t s development

Jets w i l l b e used i n t h e MSBR t o r e t u r n overflow s a l t to t h e f u e l - s a l t c i r c u l a t i n g s y s t e m and t o t r a n s f e r s a l t between t h e d r a i n t a n k , the salt s t o r a g e tank and t h e chemical p r o c e s s i n g f a c i l i t y . The d e s i g n s f t h e s e j e t s should be s i m i l a r to t h a t of water j e t s ; however, p r o t o t y p e s will b e tested in t h e Gas-Systems Te&nolsgy Facility along w i t h t h e proposed siphon-break p i p i n g .

10.4.7

Task 9 . 1 . 3

A f t e r h e a t removal systems development

A d r a i n tank system i s weeded f o r molten-salt r e a c t o r s which will c o o l t h e off-gas which p a s s e s through i t and w i l l remove t h e a f t e r h e a t i n case of a quick d r a i n a f t e r shutdown s f power. The proposed c o o l i n g system i s similar to that used f o r t h e MSW except t h a t NaK thermal convection i s used i n s t e a d of condensing steam. Although t h i s i s a very important system, t h e d e s i g n i s s t r a i g h t f o r w a r d and a minimum of development work should b e r e q u i r e d . D e t a i l s o f t h e development work r e q u i r e d have not been determined.

Although i n - l i n e a n a l y t i c a l d e v i s e s w i l l b e developed f o r f u t u r e moltens a l t r e a c t o r s , o c c a s i o n a l samples w i l l weed t o b e remkved and analyzed i n a h o t c e l l . A s u i t a b l e sampling method w i l l b e developed.

10.4.9

Task 9.1.5

Parametric e v a l u a t i o n s t u d i e s f o r xenon removal

S t u d i e s w i l l be made t o determine the e f f e c t s on xenon poisoning of sych v a r i a b l e s as bubble diameter d i s t r i b u t i o n , void f r a c t i o n bubble sepa r a t o r e f f i c i e n c y , mass t r a n s f e r c o e f f i c i e n t s , p e r m e a b i l i t y sf g r a p h i t e , off-gas recyclbe time, i o d i n e removal t i m e , loop temperature, and loop pressures. I f additional development work i s i d e n t i f i e d by t h e s e s t u d i e s , t h e work involved w i l l b e d e s c r i b e d i n f u t u r e s u b t a s k s .

10-32 10.5

TASK GROUP 9.2

10.5.1

BbJ ectivea

COQUNT-SALT TECmOE9GY DEVELQ

The o b j e c t i v e of t h i s t a s k P Q U ~ i s t o develop t h e techmology that is required for design, c o n s t r u c t i o n , and operation of t h e c o o l a n t - s a l t system of a m o l t e n - s a l t test reactor, and fo+ c o n f i d e n t scale-up to a m o l t e n - s a l t demonstration reactor.

10 5 3

Funding

10.5.4

Facilities

The Coolant-Salt Technology F a c i l i t y (CSTF) w i l l s e n e as the primary tool for work in t h i s t a s k roup he f a c i l i t y ,3 3 s h o r n schematicalHy in Pig. 1 0 . 5 . 4 , c o n s i s t s sf a pump, a s a l t - t o - a i r h e a t exchanger, a l o a d orifice, a drain t a n k , a s u r v e i l l a n c e specimen assembly, a c s r r s s i o n product t r a p , a s a l t monitoring vessel, and the n e c e s s a r y connecting p i p i n g and a u x i l i a r y equipment. The main loop i s c o n s t r u c t e d of 5-in. BasteEloy N p i p e and i s equipped with s m a l 1 e r diameter p i p e t a p s on b o t h t h e pump discharge and the pump s u c t i o n l i n e s to p e r m i t attackment of paraaiei circuits that b e used individUaiiy or s i m i ~ t a n e ~ ~ s i y eriments. A f i x e d o r i f i c e , l o c a t e d a t mid-lo~p, produces p of ~ O O~ / m z($2 p s i ) and limits t h e main l o o p salt flow to 50 P i t e r s / s e c (785 gpm). Impact tubes and o r i f i c e s are used t o c o n t r o l the s a l t f l o w at 8 . 1 3 l i t e r / s e c ( 2 pm) i n the s a l t m o n i t o r i n g vessel amd 6 . 6 1 Piterlaee (0.15 gpm) in t h e ecsnsmizer l o o p . A m i x t u r e of HaeHltlatl and BF3 i s s u p p l i e d to t h e v a p o r s p a c e of t h e pump bowl f o r salt composition c ~ n t r ~ and l , pure helium enters t h e pump b o w l as shaft purge, The gas s p a c e s i n the pump bowl, f l o a t - t y p e l e v e l chamber, s a l t ~ ~ ~ ~ i t o k - i n g vessel, and c o l d t r a p a r e i n t e r c o n n e c t e d f o r ljlquid level c o t a t ~ - ~i nl these c h a d e r s e

In addition t o t h e CSTP, t h e Components Test F a c i l i t y , t h e test reactor mockup, t h e t e a t r e a c t o r , a d t h e demonstrator react^^ w i l l ales advance c o o l a n t - s a l t system technolo

Table 10.5.2.

Schedule

for work in Task Group 9.2 - Coolent

salt

Fiscal

technology year 1981

9.2.8

Coolant 9.2.1.1 9.2.1.2 9.2.1.3 9.2.1.4 9.2.1.5

9.2.2

Salt Technology Facility Tritium distribution calculations Hydrogen and deuterium studies Corrosion product trapping Salt shemistry Material surveillance

Evaluation and design component e

of larger

development

1982

1984

1985

TababPt.2 10.5.3. fJp$eratingfund requirementsfor Task Gkoup9.a - Coolant (costs

9.2.1

Coolant 9.2.1.1

9.2.1.4 9.2.1.5

Salt Technology FacfPity Tritium distribution ca?leulatiom3 Hydrogen and deuteriusn studies Colncosion produce trapping Salt chemistry Material surveillance

Subtatal.

9.2.1

9.2.1.2 9.2.1.3

9.2.2

Evaluation

and design

1975

1976

1977

33.5

&%I

34 5 5 --149

60 20 1Q

20 5 5

29Q

100

operating

funds

for

techn~lcsl%)~ devehqmmt

1978

1979

19 se,

1981.

1982

198%

1984

aoa

2QQ

100

200

of Barger

CQlDpOPl@IlfS

Total

salt

in 1QQO bdollars)

Task Group 9.2

169

290

100

1985

QRNL-DWG 74-8978

MANMALLV OPERATED DAMPER

ECONOMIZER

AIR EXHAUST l-0 BLOWER

GRAVITY I-DAMPER

FREEZE_ VALVE

-4WALlZE~

DRAIN

Fig.

l.Q.5.4.

TANK

CSTF schematic.

LIME

l o -3 6 10.5.5

Task 9.2.1

CSTP s t u d i e s ( f l u o r s b o r a t e s a l t )

mis task group i n e l u d e s experimental studies pel-fomed i n 9 or in connection w i t h , t h e CSTF. The work c o n s i s t s of tests f o r determining the d i s t r i b u t i o n of hydrogen m a $eiate-%im in t h e CSTF €.POW which t h e d i s t r i b u t i o n of t r i t i u m i n t h e c ~ o l a n tsystem of an MSBR can b e i n f e r r e d , s t u d y of c o r r o s i o n product t r a p p i n g , materials s u r v e i l l a n c e s t u d i e s , and e v a l u a t i o n of i n - l i n e a n a l y t i c a l devices- Work i s also i n c l u d e d on the d e s i g n and e v a l u a t i o n of f u l l - s c a l e c o o l a n t - s a l t components; however, no e x p e r i m e n t a l work on the l a r g e r components i s covered 5n t h i s t a s k group.

Mathematical models have been devised f o r p r e d i c t i n g t h e d i s t r i b u t i o n of tritium in m o i t e n - s a l t reactor systems 3 9 4 A review w i l l b e of ail p e r t i n e n t c a l c u l a t i o n s and a d d i t i o n a l c a l c u l a t i o n s wFBl b e c a r r i e d o u t as necessary f o r planning and a n a l y z i n g the e x p e r i m e n t a l program p r i o r t o , and i n c o n j u n c t i o n with, t h e d e u t e r i u m - i n j e c t i o n tests.

PO.5,5.2

Subtask 9.2.1.2

Hydrogen- and d e u t e r i u m - i n j e c t i o n tests

The o b j e c t i v e of t h i s work i s t o simulate t h e m t i c i g a t e d behavior of t r i t i m i n the e o s l a n t - s a l t system and to i n v e s t i g a t e t h e p o s s i b i l i t i e s of u s i n g t h a t system as a barrier t o resist m i ration of tritium from t h e f u e l system t o t h e steam s y s t e m a d t h u s t o keep t h e c o n c e n t r a t i o n of t r i t i u m i n t h e MSBR s t e a m system from r i s i n g above t h e maximum a c c e p t a b l e level.36 ~t i s p o s s i b l e t h a t c e r t a i n k y d ~ o g e n o u smaterials i n t h e c o o l a n t s a l t may s e r v e t o s e q u e s t e r t h e tritium and t h u s p r e v e n t i t s d i f f u s i o n i n t o the s t e m system.

The procedure for t h e i n i t i a l i n j e c t i o n experiments w i l l b e t o a l l o w a h o r n volume of deuterium t o d i f f u s e d i r e c t l y i n t o t h e c i r c u l a t i n g salt and, by a p p r o p r i a t e sampling and analyticalb techniques, t o determine the resulting change i n the deuterium c o n c e n t r a t i o n s i n t h e salt and o f f - g a s streams

91ne i n i t i a l injection t e s t a are expected to p r o v i d e q u a n t i t a t i v e d a t a only on t h e deuterium c o n t e n t of the salt and t h e off-gas. Later tests will be designed t o y i e l d q u a n t i t a t i v e data on the m o u n t s€ d e u t e r i m which d i f f u s e s through the w a l l s of t h e salt p i p i n g , s i n c e t h i s informat i o n i s e s s e n t i a l to o b t a i n i n g a meanin fuB deuterium material b a l a n c e and t o p r e d i c t i n g b e h a v i o r of tritium i n an MSBW. '%he equipment for t h e s e tests m y t a k e the form of a test s e c t i o n i n s e r t e d in one of the s i d e loops of t h e CSTP.

18.5.5.3

Subtask 9 . 2 . 1 . 3

Corrosion product t r a p p i n g

The objectives of the corrosion-product t r a p p i n g s t u d i e s are to (I) demons t r a t e t h a t Na3CrFg can b e d e p o s i t e d o n t o a c o l d s u r f a c e in an engineeringscale sodium f l u s r o b o r a t e c i r c u l a t i n g loop and (2) determine t h e c h a r a c t e r

...

UL.

h . .

10-3 7 of the d e p o s i t . A c o l d t r a p u n i t , i n s t a l l e d i n a s i d e loop of t h e CSTP, w i l l b e used f o r the c ~ s r o s i o nproduct t r a p p i n g s t u d i e s . A d e s c r i p t i o n of t h e cold t r a p amd associated f l o w cfrcuit i s g i v e n i n t h e F i n a l Syst e m Design BESCriptiQn33 f o r the CSTP.

The c o r r o s i o n p r o d u c t t r a p p i n g s t u d i e s w i l l b e c a r r i e d out in two p h a s e s . %he f i r s t phase will consist of o b s e r v a t i o n s and s t u d i e s which are lnade w h i l e o t h e r work, such as deuterium i n j e c t i o n and s a l t chemistry s t u d i e s , i s b e i n g c a r r i e d o u t . During t h i s phase, t h e c o l d t r a p s t u d i e s w i l l b e of lower p r i o r i t y than t h e o t h e r work. The second phase of t h e e x p e r i mental work w i l l c o n s i s t of s t u d f e s wherein t h e types of d e p o s i t s and rates of d e p o s i t i o n are observed under c o n d i t i o n s where the 3napaarity level i n she s a l t i s a d j u s t e d by means of c o n t r o l l e d a d d i t i o n s . Tests w i l l b e c a r r i e d out. f n which t h e c h - ~ o m i mc o n t e n t of t h e s a l t w i l l b e changed by direct chromium a d d i t i o n , and Fm which steam w i l l b e i n j e c t e d d i r e c t l y inatGI ithe Salt.

10.5.5.4

Subtask 9.2.1.4

S a l t chenistry

The chemistry of S o d i m f h o r o b Q r a t e is being studied to (1) d6%&Pop t i o n i n s u p p o r t of t h e tritium and c o ~ ~ o s i oexperiments, n and (2) develop t e c h n i q u e s for sampling and in-line a n a l y s i s which are s u i t able for large m o l t e n - s a l t reactors. A s a l t - m o n i t o r i n g vessel i s prov i d e d i n t h e CSTF which w i l l b e used f o r t e s t i n g in-line a n a l y t i c a l technfques for measurements such as proton c o ~ ~ e n t r a t i oi n t h e s a l t . The primary work. r e g a r d i n g s a l t c h e ~ 1 5 ~ tis ~ yc o ~ e r e di.n s e c t i o ~ ~5s and 6. The e f f o r t i n t h f s subtask w i l l b e r e s t r i c t e d t o (1) a s s i s t i n g investigators fm a p p l i c a t i o n of the CSTF t o t h e v a r i o u s problem areas, and (2) demonstrating through o p e r a t i o n of t h e CSTF t h a t prsposed S O ~ U t i o n s are a p p l i c a b l e t o an actual. reactor system. 10.5.5.5

Subtask 9.2.1.5

&faterialss u r v e i l l a n c e tests

The materials s u r v e i l l a n c e t e a t s w f l l b e conducted casing the specimen s u r v e i l l a n c e s y s t m w k f e h i s provided fra t h e CSTF. Because of p l a n s f o r using the specimen sumeilBance assembly i n the d e u t e r i u m - i n j e c t i o n tests, t h e assembly has been r e d e s i g n e d s o t h a t i t will b e a b l e to serve t h e c l p ~ i l l r o l e of i n j e c t i o n t u b e and specimen holder,36

... .... .._.' 8 w&.

.. ...... %

... ..... .m>

....

: i.. ,.. .&.A

Tke o b j e c t i v e of t h e material s u r v e i l l a n c e tests i s ts p r o v i d e informtion on the c o m p a t i b i l i t y of the NaBF4-NaF s a l t w i t h H a s t e l l o y M and with o t h e r s e l e c t e d materials. C O ~ ~ O S ~asQ ~i n, d i c a t e d by t h e s u m e i l lanee specimens, w i l l b e determined by w e i g h t change measurements, dimensional changes, and metallography on p o r t i o n s of the specimens. E ~ e c ~ t of i ~ these n tests w i l l be handled as a p ~ sft the materials development e f f o r t which i s covered i n S e c t i o n 2.

18-38 16.5.6

Task 9 . 2 . 2 E v a l u a t i o n and d e s i g n 5f l a r g e r components f o r c o o l a n t - s a l t technolow development

The o b j e c t i v e of t h i s t a s k i s to e v a l u a t e the p e ~ f o m n ~ofe f u l l - s c a l e c o o l a n t - s a l t compsnents and system. A single c o o l a n t loop in t h e reference d e s i g n MSBW operates w i t h a salt flow rate of 1 m 3 / s e c (16,068 gpm) which i s a f a c t o r of 28 larger than t h a t f o r t h e CSTP. The experience gafned i n t h e e~ecutionof Task 9,2.1 i n the CSTP w i l l b e a p p l i e d ts the designs of f u l l - s c a l e models of t h e c o l d t r a p , t h e BF3 economizer, and the p a r t i c l e traps, and components of similar d e s i g n will b e tested i n the G ~ ~ n p o n e n tTse s t Facility.

10 6 l e

Obj estive

me objective of t h i s task group i s to develop t h e technology r e q u i r e d for the r e l i a b l e e v a l u a t i o n , design, and f a b r i c a t i o n of molten-salth e a t e d s t e a m generators.

v.:i . ..

Liquid-heated steam g e n e r a t o r s are r e l a t i v e l y new i n the power g e n e r a t i o n field, and much development e f f o r t w i l l b e required t o p r o v i d e a moltens a l t - h e a t e d s t e a m g e n e r a t o r w i t h t h e essential c h a r a c t e r i s t i c s of reliabilityp safety, performance, m a i n t a i n a b i l i t y , and economy.

In o r d e r t h a t s t e m get-ae~atorsear%be s u p p l i e d that will operate in a safe and r e l i a b l e manners WOK^ i s spatlined in t h i s task group f o r deve~ocing the techno~ogyand s k i ~ required ~ s to csmplete t h i s 0b-j ective Portions of the e x t e n s i v e development work being done with liquid-metalh e a t e d steam g e n e r a t o r s w i l l be u s e f u l t o the Molten-Salt Reactor Frogran. The l i q u i d - m e t a l and the m o l t e n - s a l t steam g e n e r a t o r s have many problems i n cornon amd t h e LmBB e erience will b e used in p l a n n i n g the n e c e s s a r y development program t o a c h i e v e t h e o b j e c t i v e sf this task group.

10.6.2

Schedule

The s c h e d u l e f o r work i n this t a s k group i s shown i n Table lO.6.2.

me plan f o r t h e development of s t e m - s y s t e m technolo

is aimed a l m o s t e n t i r e l y a t t h e i n t e r f a c e between t h e coolant s a l t an t h e steam systere. me p l a n i s d i v i d e d i n t o f i v e pro ressfve tasks, with i n t e r f a c e s between t a s k s s e l e c t e d t o provide advanced levels of confidence i n t h e technology b e f o r e the commitment i s made t o proceed i n t o the n e x t t a s k . "he f i r s t task (9 e3.6) Which is presently in p%0gIce8S9 PS the begbning Of t h e i n d u s t r i a l program and involves i n d u s t r y i n p e r f o d n g conceptual design studies of molten-salt steam generators. This design-study task, which w i l l be completed i n 1976, wtHI provide i n d u s t r i a l recornendations fer development ~ e ~ p i ~ e ~ ~ e n t s .

u,.;.:;

.....

<.:<.2

Table

10.6.2.

Schedule

for

work

in Task

Group

9.3

- Steam

tecbndogy Fiscal

1975 9.3.1

9,3,2

Industrial studies 9.3.1.1 9.3.1.2 9.3.1.3 9.3.1.4 9.3.1.5 9.3.1.6

steam

generator

design

11000~Mid(e) conceptual Lower feedwater studies MSTR conceptual Recommended R&D Review corrosion work Review CSTF plans

Design studies and small scale development 9.3.2.1 CSTF steam generator studies 9.3.2.2 Develop pressure relief device 9.3.2.3 Small leak detection 9.3.2.4 Small leak wastage 9.3.2.5 Prelimrimry startup and control studies 9.3.2.6 Develop fabrication tCXhni~UeS

9.3.2,7 9.3.2.8 9.3,Z.S' 9.3.2.10

Alternate steam generator materials Thermal-hydraulic ana physical property data Coolant salt extrusion coefficient Update R&D plan

.- .-

year

development

Fiscal

9.3.3

year

Steam generator tube test strand 9.3.3.1 Conceptual design 9.3.3.2 Criteria and pressure relief system design 9.3.3.3 Maintenance, cleaning, and il-tspection procedures 9.3.3,4 Test stand Title Z and Title II design 9.3.3.5 Test stand fabrication 9.3.3.6 I)esi@~ Of tube test asse?llbly

9.3.3.7

Fabrication assembly Qperakion

9.3.3.8

9.3.4

Steam

generator

installation 9.3.4.1 9.3.4.2

9.3.4.3 9.3.4.4

9.3.4.5 9.3"4.6

model

tube

test

-... __test:

Preliminary

design

model

skeam

generator

Final steam

design

model.

generator Fabrication of nwdel steam generator SGMTI conceptual design %XTI Title I and Title II design SGMTI canstruction

---__-

-_.

.--

Table

9.3.4.7 9.3.4.8

9.3.4.9 9.3.4.10

10.6.2

(continued)

Model steam generator testing Overpressure system testing Steam leak detection Steam gemrator StartUp

9.3.5

9.3.4.11

Destructive and evaluation

Equipment

and controls development Establish criteria

9.3.5.1

examination

10-42

'%he second task ( 9 . 3 . 2 ) w i l l CQnSist Qf small-scale e x p l o r a t o ~ q fdevelopITEnt n@CeSSaFj f O K the design and operation Of a IllUltitube st@EUTl g e n e r a t Q r assembly d e s c r i b e d under the t h i r d task ( 9 . 3 . 3 ) A l s o , the second t a s k will begin preHiminary d e s i g n of s t a r t u p m d c o n t r o l s y s t e m for s t e a m g e n e r a t o r s , and development of f a b r i c a t i o n t e c h n i q u e s and a l t e r n a t e mater i a l s in s u p p o r t of t h e t h i r d task. S I T E I P P - ~ C tests ~ ~ ~ of 100 to 150 kW w i l l b e p e ~ f o m e du s i n g a side stream of t h e CSTP. The work of t h i s task shoubd be well underway by t h e end of 1978 t o pr~videa firm b a s i s f o r beginning desi af the S t e m Generator Tube T e s t Stand (STTS) of the t h i r d t a s k ( 9 . 3 . 3 ) e

The t h i r d t a s k ( 9 . 3 . 3 ) w i l l i n c o r p o r a t e t h e development r e s u l t s o b t a i n e d t h u s f a r i n t o t h e d e s i g n of a S t e m Generator Tube T e s t Stand i n c o r p o r a t ing several fbklbl-size stern tubes (STTS). M d t i t U b e test ~ ~ ~ s e d lsf ies industrial d e s i g n w i l l b e o p e r a t e d i n t h e STTS.

The f o u r t h t a s k ( 9 . 3 . 4 ) w i l l involve the design, c o n s t r u c t i o n , and operation of the S t e m Generator Model T e s t I n s t a l l a t i o n ( S W I ) . Although t a s k 9.3.3 w i l l not b e complete i n 1981, the n e c e s s a r y infomatlola from this task w i l l b e a v a i l a b l e f o the ~ design of t h e model s t e a m generator ana t h e S ~ T by I this time.

The f i f t h task i n v o l v e s e s t a b l i s h i n g the equipment and c o n t r ~ l sc r i t e r i a n e c e s s a r y f o r a l l steam generator o p e r a t i n g modes. ~ f t e tr h e s u c c e s s f u l t e s t has demonstrated the adequacy of the b a s i s d e s i g n c r i t e r i a of the model steam g e n e r a t o r and its s u p p o r t equipment, t h e f i n a l d e s i g n , fabrfCa%iUn, and testing O f HsTR prQtotype S t e r n genePatOKs Will b e g i n in ET 1981 (see Section 1 3 ) . The m o l t e n - s a l t test. r e a c t o r mockup (MSTRM) w i l l c ~ n t a i na t least one steam g e n e r a t o r u n i t i n t h e mockup of t h e C O O ~ ~ R ~ w i t h the r e q u i r e d o v e r - p r e ~ ~ u rper o t e c t i o n system. Although only l i m i t e d steam g e n e r a t o r performanee t e s t a can be performed i n the mockup, t h e safety of the s t e m g e n e r a t o r and i t s over-pressure protectfsn system be demonstrated by simulating a s t e m t u b e ruptu.lpe. procedures f o r s e m i - d i r e c t maintenance, cleanup a f t e r a tube r u p t u r e , and inservice i n s p e c t i o n will b e t e s t e d by FY 1986.

10.6 3 0

Funding

Operating fund requirements f o r this t a s k group are given in Table 16.6.3.B, and c a p i t a l equipment fund ~ e q u i ~ ~ ~are e n given. t s i n Table 10.6.3.2. A u t h ~ r i z a t i o nof funds for t h e design and c o n s t r u c t i o n of the Steam Generator Tube T e s t Stand i n the mount of $4 lnxkim¶w i l l b e r e q u i r e d early i n m 1979. A u t h o r i z a t i o n of funds for the desi and c o n s t r u c t i o n of t h e Model S t e m &ne~ato% T e s t I n s t a l l a t i o n i n t h e mount sf $20 million w i l l b e areq u i r e d early i n IFY 1981,

Table 10.6.3.1.

Operating fund requirements f o r Task Croup 9.3 - Steam technology development ( c a s t s i n 1000 d o l l a r s ) F i s c a l year 1975

9.3.1

I n d u s t r i a l steam generator design studies 9.3.1.1 1000-W(e) conceptual 9.3.1.2 Lower feedwater s t u d i e s MSTR conceptual 9.3.1.3 9 . 3 . 1 . 4 Recommended R&D 9.3.1.5 Review c o r r o s i o n work 9.3.1.6 Review CSTF p l a n s S u b t o t a l 9.3.1

9.3.2

1976

1977

1978

1979

120 30 100

120

1980

1981

50 168

45 30

6 7

250

Design s t u d i e s and small scale

deVelQpQf5lt 9.3.2.1 CSTF steam g e n e r a t o r studies 9.3.2.2 Develop pressure r e l i e f device 9.3.2.3 Small l e a k d e t e c t i o n 9.3.2.4 Small l e a k wastage 9,3.2.5 Preliminary s t a r t u p and control studies 9.3.2.6 Develop f a b r i c a t i o n techniques 9.3.2.7 A l t e r n a t e steam generator

150 BOO 30

100

materials 9.3 2.8 e

Thermal-hydraul i c and physical. property d a t a

120

200

120 120

120

1982

1983

1984

1985

1986

Table

-p__----

1975 51.3.2.9

9.3.3

9.3.2.10

Coalarnt salt extrusion coefficient Update R&D plan

Subtotal

9.3.2

Test

9.3.3.6

9.3*3.8

Design of assembly Fabrication assembly OpeKatioR

Subtotal

9.3.3

9.3.3.7

9.3.4

stand

1976

Steam generatar tube test stand 9.3.3.1 Conceptual design 9.3.3.2 Criteria and pressure relief system design 9.3.3.3 Maintenance, cleaninsg, and inspection pracedures 9.3.3.4 Test stand Title I and Title X3c design 9.3.3.5

10.6.3.1

(continued)

1977

1978

130

___ 540

p--e 580

1979

Fiscal

year

1980

1981

360

240

1982

1983

350 __3.50

55Q

50 390

50 60

100

fabrication

tube

test

tube

test

Steam generator model test installation 9.3.4.1 Preliminary design of model steam generator 9.3.4.2 Final design of model steam generator

200 40

228

380

200 200 410

1OQ

I.00 300

550

1984

1985

1986

Table

10 * 6 * 3.1

(continued)

Fiscal. year

9.3.4.3 9.3.4.4 9.3.4.5 9 J3.4.6 9.3.4.7 9,%.4.8 9.3.4.9 9.3.4.10 9.%.4.B1

Fabrication of mmkl steam generator sm1 conceptmB design SW1 Title I and Title HI desigm SGMTI construct%an Model steam generator tasting Overpressure system testing steam Peak. deteetiam steam genc3rator startup Destructive els;aminittian and

Subtotd 9.3.5

Total

Equipment

200

9.3.4 arid

cantrola

Establish

Subtotal

9.3.5 funds

8QQ

aoo

evaluation

9.3.5.1

operating

200

development

criteria ---~-

for

Task

Group

9.3

280

580

600

8PQ

200

450

1.50

150

1090

1250

850

12QQ

Table

Capital

lQ.6.3.2.

equipment

fund

requiremnts (costs in

1976 9 O3.2 O1

~Hfscellanaous

instruments

9.3.2.2

Miscelf~.eous

qufpnmt

9.3.2.4

Wiscellaneous

equipnnent

9.3.3.8

MisceBaaneow

instrumants

9.3.5

Equipment

Atal

capital

and equipments

controls for

Km8

for Task dollars)

1977

Group

1978

9.3

19 79

- Steam

technology

Fiscd

y@ar

1980

I.981

1982

development

1983

1984

19 85

10 and instrumentci

1Q 10

20 criteria

Task

Group

9.3

200 -200

256 250

10.6.4

Facilities

"he f a c i l i t i e s necessary f u r steam-eystem technology development w i l l cons i s t f o r t h e most p a r t of m o l t e n - s a l t f a c i l i t i e s w i t h t h e steam g e n e r a t o r as the primary focus. Stem-system equipment n o t i n contact w i t h s a l t w i l l i n v o l v e the scale-up and a d a p t a t i o n of existing technology and will b e done by i n d u s t r i a l f i r m s . The f a c i l i t i e s r e q u i r e d % o r t h e development of m o l t e n - s a l t steam generators are covered i n t h e folPowing s u b s e c t i o n s .

10.6.4.1

F a c i l i t i e s f o r Task 9 . 3 . 1 c o n c e p t u a l design s t u d i e s

I n d u s t r i a l steam g e n e r a t o r

No hardware i s r e q u i r e d f o r t h i s p o r t i o n of the i n d u s t r i a l program which i s p r e s e n t l y i n p r o g r e s s . A s d i s c u s s e d i n Subtask 9.3.1.4, t h e industrial f i m performing this s t u d y w i l l make r e c o r n e n d a t i o n s f o r a development program f o r moltem-salt steam g e n e r a t ~ r s .

10.6.4.2

F a c i l i t i e s for Task 9.3.2

Small-scale e x p l o r a t o r y development

Exploratory d e ~ e l ~ p m e nwt i l l b e performed b o t h as secondary f u n c t i o n tests in o t h e r s a l t t e s t f a c i l i t i e s and as primary ~ U R C ~ Ptests O ~ i n new t e s t facilities.

The Coolant-Salt Technology F a c i l i t y w i l l be u t i l i z e d fer small-scale, s i n g l e - t u b e , s t e m g e n e r a t i o n tests (Subtask 9.3.2.11, and f o r p r e l i m i n a r y Separate development of a steam-leak d e t e c t o r system (Subtask 9.3.2.3). f a c i l i t i e s w i l l b e r e q u i r e d f o r development of a p r e s s u r e r e l i e f d e v i c e (Subtask 9 . 3 . 2 . 2 ) and for steam wastage parameters (Subtask 9 . 3 . 2 . 4 ) . The development of f a b r i c a t i o n techniques and a l t e r n a t i v e materials (Subtasks 9 . 3 . 2 . 6 and 9 . 3 . 2 . 7 ) are material development problems and w i l l b e performed i n e x i s t i n g materials development f a c i l i t i e s . Small-scale f a c i l i t i e s w i l l b e r e q u i r e d f o r o b t a i n i n g p r e c i s e thermal hydraulie:, and p h y s i c a l d a t a for the c o o l a n t s a l t (Subtask 9.3.2.8) such as have been measured f o r sther s a l t s . I n a d d i t i o n t o t h e e n g i n e e r i n g p r o p e r t i e s data a t normal o p e r a t i n g t e m p e r a t u r e s , a s p e c i a l i n v e s t i g a t i o n w i l l be made of t h e c o o l a n t s a l t n e a r i t s l i q u i d u s temperature (Subtask 9.3.2.9) s i n c e p o r t i o n s of a steam g e n e r a t o r w i l l o p e r a t e n e a r t h e l i q u i d u s temperature. I n v e s t i g a t i o n s w i l l b e performed t o determine t h e I E X ~ Q S C Q ~ ~ C . d e n s i t y change of t h e c o o l a n t at b o t h t h e l i q u i d u s and t h e solid-phase t r a n s i t i o n temperature. Information on t h e r e s i s t a n c e of t h e s a l t t~ ext r u s i o n w i l l b e measured. ~

.:.*

10-48

10.6.4.3

F a c i l i t i e s f o r Task 9 . 3 . 3 d e s i g n and development

Preliminary s t e m g e ~ ~ ~ a t o r

The major f a c i l i t y f o r this t a s k is t h e S t e a m Generator Tube T e s t Stand (STTS) which w i l l require a h e a t s o u r c e of about 3 MW(t;B and must aceommodate full-length, multifube t e s t assemblies, which w i l l be designed by i n d u s t r i a l firms. S e e S u b t a s k s 9 . 3 . 3 . 1 through 9 . 3 . 3 . 8 . The STTS w i l l i n c l u d e a system f o r c i r c u l a t i n g molten s a l t and a s t e m feedwater system that can be o p e r a t e d a t ~ ~ b ~ ~ i to ir cs ua pl r ~ r i t i c a l p r e s s u r e s . Feedwater t r e a t m e ~ ~ will t b e equiva%ent to t h a t of supercritical power p l a n t s . In addition t o t h e r e q u i r e d subsystems f o r support O f t h e s a l t and steam-feedwater systems, a p r e s s u r e r e l i e f system w i l l be required to p r o t e c t t h e salt p i p i n g from o v e r p r e s s u r e i n t h e event of steam-tube failure.

10.6.4.4

F a c i l i t i e s f o r Task 9.3.4 Model t e s t i n g i n t h e S t e m Generator Model T e s t I n s t a l l a t i o n (SGEEI)

Steam g e n e r a t o r models of 20- t o 25-%J(t) capacfty w i l l b e t e s t e d i n t h e Steam Generator Model Test I ~ s t a B h t i o nwhich ill be l o c a t e d in t h e Cornponents Test F a c i l i t y ( d e s c r i b e d i n Task Group S.lS>. This installatian will c o n s i s t sf a 3 Q - f i T & t ) s a l t h e a t e r , c o o l a n t s a l t system, over p r e s s u r e p r o t e c t i o n system, s u p e r c r i t i c a l stem system, heac dump and o t h e r s u p p o r t equipment n e c e s s a r y to s i m u l a t e i m p o r t a n t p o r t i o n s of a s t e a m g e n e r a t o r m d ailow study of t h e phenomena which t a k e piace in a m o i t e n - s a ~ t - h e ~ t e d steam g e n e r a t o r .

A c o n c e p t u a l d e s i g n s t u d y , presently i n p r o g r e s s by F o s t e r rneeler corpor a t i o n , umder ORNL s u b c o n t r a c t , will i n c l u d e c o n c e p t u a l d e s i g n s , recornmendations f o r steam g e n e r a t o r development and critical reviews of p r e s e n t plans *

10 6.5 1 e

F o s t e r Fbkaeele~C o r p o r a t i o n , under ORNL s u b c o n t r a c t , i s p r e p a r i n g a conc e p t u a l d e s i g n sf a steam generator f o r t h e 1006-%/&d(e)MSBR reference ' p l a n t . This steam g e n e r a t o r i s t o u t i l i z e a s u p e r c r i t i c a l steam c y c l e to produce s t e m a t 1000°F and 3566 p s i a from feedwater a t 700°F.

10.6.5.2

Subtask 9.3.1.2 F e a s i b i l i t y s t u d y f a r use of Power feedwater t e m p e r a t u r e

.... ..... c.z;.

15-49 b o t h s u p e r c r i t i c a l and s u b c r i t i c a l s t e a m systems. I f t h e r e s u l t s of t h e i n v e s t i g a t f o n are favorable, c o n c e p t u a l d e s i g n s w i l l b e prepared f o r one o r both c o n d i t i o n s . $0.61.5.3

Subtask 9.3.1.3

Conceptual d e s i g n of WTR stem g e n e r a t o r

A steam g e n e r a t o r conceptual d e s i g n w i l l b e prepared of a s i z e a p p r o p r i a t e f o r t h e MSTR; however, the stem g e n e r a t o r s i z e h a s not been f i x e d a t this t i m e . The d e s i g n w i l l b e based on an e v a l u a t i o n of the r e s u l t s of subtasks 9,3.1.1. and 9.3.1.2 above.

10.6.5.4

Subtask 9.3.1.4

Recommend R &I D program

After c o ~ i ~ p l e t i nSubtasks g 9.3.1.1 through 9.3.1.3, F o s t e r T4keeler Corporat i o n , under OkzNL s u b c o n t r a c t , w i l l recommend a r e s e a r c h and development program f o r c a r r y i n g o u t the work n e c e s s a r y for development sf s t e a m g e n e r a t o r s i n viey t h e i r e x p e r i e n c e w i t h c o n v e n t i o n a l steam g e n e r a t o r design and w i t h t h e background of having performed m o l t e n - s a l t stem g e n e r a t o r s t u d i e s . A r e e v a l u a t i o n and p o s s i b l e r e d i r e c t i o n of emphasis f o r t h e remainder of the steam g e n e r a t o r develupntent program is p o s s i b l e as a r e s u l t of t h e s e KeComendationS.

ibO.Q.5.5

Slabtask 9.3.1.4 c o r r o s i o n work

C r i t i c a l review of HastePloy N-steam

F o s t e r Wheeler Corporation, under O W s u b c o n t r a c t , w i l l p r o v i d e a c r i t i c a l review of p a s t and p r e s e n t HastelPoy N-to-steam c o r r o s i o n work and make recommendations un s t e a m g e n e r a t o r materials. It i s likely t h a t t h e s e reCQB.EII@ndationSW i l l l e a d t o f u r t h e r fnaterhfs S t U d i e s since only l h i b e d W Q F ~has been dona om materials b e h a v i o r i n salt-steam envirsments. 18.6.5.6

Subtask 9.3.1.6

C r i t i c a l review of ORNL p l a n s f o r CSTF

F o s t e r Wheeler Corporation, under O W L s u b c o n t r a c t , w i l l review and e v a l u a t e O m ' s steam g e n e r a t o r technology loop (which w i l l o p e r a t e i n c o n j u n c t i o n w i t h t h e CSTF, Task 9.2.1). A small test of 100 t o 150 BrWCt) will b e d e s c r i b e d i n a c o n c e p t u a l d e s i g n r e p o r t . See Subtask 9.3.2.1.

10.6.6 10.6.6.1

Task 9 . 3 . 2 Design s t u d i e s and s m a l l scale e x p l o r a t o r y development Subtask 9 . 3 . 2 . 1 S m a l l scale stem g e n e r a t o r tests i n t h e GSW (See p a r a 18.5.4)

Important p r e l i m i n a r y i n f o r m a t i o n concerning t h e g e n e r a t i o n of stem in a molten-salt-heated exchanger w i l l be o b t a i n e d as a basis f o r ~ K O ceedilmg w i t h l a r g e r - s c a l e steam g e n e r a t o r development. A small bypass on the CSTF w i l l be used t o supply s a l t a t a s u f f i c i e n t r a t e t o p r o v i d e

10-56

50 to 150 kW sf heat ts the exchanger. Information w i l l b e developed on d e s i r a b l e tube c o n f i g u r a t i o n s , h e a t t r a n s f e r c o e f f i c i e n t s , and flaw stability.

'Fer p r e v e n t o v e r p r e s s u r e of the coolant-salt system i n t h e event of a s t e m tube f a i l u r e , a p ~ e s s u r er e l i e f d e v i c e and a c o l l e c t i o n system for t h e e f f l u e n t must b e provided. A d e v i c e must be developed which will o p e r a t e r e l i a b l y a t high temperature and in contact w i t h molten salt. This device may be an a d a p t a t i o n of an e x i s t i n g d e v i c e .

10.6.6.3

Subtask 9 . 3 . 2 . 3

Development of small-leak d e t e c t i o n system

Tfte CSTF w i l l b e used t o develop methods f o r d e t e c t i n g small s t e m l e a k s i n t o t h e coolant s a l t . E a r l y d e t e c t i o n sf a small steam leak from t h e steam generator will allow shutdown and r e p a i r b e f o r e t h e f a i l u r e prograsses ts the s t a g e where the p r e s s u r e relief s y s t e m would b e brought i n t o s e m i e e . I n j e c t i o n s sf water i n t o t h e C Q Q ~ E sL a~ l~t of the CSTP and the e v a l u a t i o n of v a r i o u s l e a k - d e t e c t i o n methods w i l l f o m t h e b a s i s f o r further devel~pment in the l a r g e r steam generator f a c i l i t i e s t o follow.

B8.6.6.4

Subtask 9 . 3 . 2 . 4

10.$.6,5

Subtask 9.4.2.5 P r e E M n a r y d e s i g n s t u d y of s t e m g e n e r a t o r startup and c o n t r o l s y s t e m

Determination of sntall-1eak wastage parameters

%e S t a r t u p SysteHB must provide f o r t h e i n i t i a l CSUpling of the Salth e a t e d s t e m g e n e r a t o r to the steam system without f r e e z i n g of salt and w i t h a minimum sf thermal shock. A s e p a r a t e fossil-fired s t a r t u p system with a c a p a c i t y sf about l8X of rated p l a n t c a p a c i t y may b e n e c e s s a r y . ni3K). s t U d $ e s , i n c l u d h g COTtlpUter s h d a t i o n s , Will illVeStigat@ v a r i o u s startup and c o n t r o l schemes aaad p ~ s v P d ea basis f o r f u r t h e r development in t h e l a r g e steam g e n e r a t o r s t o follow.

u.: 1

k....,

110-51

10.6.6.6

Subtask 9 . 3 . 2 . 6 generator

Develop f a b r i c a t i o n techniques f o r s t e m

S p e c i f i c j o i n t d e s i g n s , f a b r i c a t i o n p ~ o ~ e d ~ and r e ~i n,s p e c t i o n procedures have n o t been chosen a t this t i m e . Problems w i l l b e r e s o l v e d as they arise in the d e s i g n and w i t h the p a r t i c i p a t i o n of i n d u s t r i a % firms.

10.6.6.7

Subtask 9.3.2.7 I n v e s t i g a t e and develop a l t e r n a t i v e steam g e n e r a t o r materials

I n t h e event t h a t PIastePloy N i s incompatible w i t h steam under stress, other materials Will be illvestigated. IfafQa?natiQnon the colIlpatibi%ity $80 and I n c o n e l $00, with steam is of many materials, i n c l u d i n g IIXS~QY a v a i l a b l e . However, t h e e v a l u a t i o n of t h e s e materials i n c o n t a c t w i t h coolant s a l t w i l l b e necessary.

An e v a l u a t i o n w i l l b e made sf d u p l e x t u b i n g as a sslutisn t o t h e U X ~ ~ ~ P ~ E ~ P S PPObfeIR, Where each S i d e of the tUbe 2s CQIIlpatible w i t h its PespeCtiV@ environment, namely, Incsloy $00 w i t h s t e a m and nickel w i t h the c o o l a n t s a l t . The main problems t o be r e s o l v e d a r e t h e i n t e g r i t y of t h e b i m e t a l i n t e r f a c e and j o i n i n g techniques.

10.6.6.8

Subtasks 9 . 3 . 2 . 8 and 9 . 3 . 2 . 9

These t ~ os u b t a s k s are c ~ n c e r n e dw i t h p h y s i c a l p r o p e r t i e s QH t h e c o o l a n t s a l t that are of p a r t i c u l a r fmportance t o t h e steam g e n e r a t o r d e s i g n . In a d d i t i o n t o t h e more a c c u r a t e e n g i n e e r i n g d a t a n e c e s s a r y over t h e n o m a l o p e r a t i n g temperature range (Subtask 9 . 3 . 2 . 8 ) , a d d i t i o n a l infomat i s n is ~ e e d e di n t h e r e g i o n n e a r the s a l t l i q u i d u s temperature. Temperatures a t t h e i n s i d e tube w a l l a t the tube s h e e t s u r f a c e near t h e feedwater i n l e t w i l l b e below the s a l t l i q u i d u s and, therefore, some s a l t f r e e z i n g w i l l occur. The n a t u r e of t h e f r o z e n salt l a y e r and the p o s s i b l e mechanical consequences of t h e f r e e z i n g and thawing of t h i s layer m u s t b e b e t t e r understood. This subtask w i l l investigate the p o s s i b i l i t y of d e t e r m i n i n g a n e x t r u s i o n c o e f f i c i e n t by methods similar to t h o s e used i n the e x t r u s i o n of metals. With t h i s i n f o r m a t i o n , stresses r e s u l t i n g f r o m t h e d e n s i t y change i n thawing s a l t C S U ~b e~ c a l c u l a t e d and a c s s m o d a t e d i n t h e s t e m g e n e r a t o r d e s i g n .

The two s u b t a s k s a s s o c i a t e d w i t h c o o l a n t - s a l t p r o p e r t i e s are as f ~ l l o w s : Subtask 9 . 3 . 2 . 8 -Assess the adequacy of the thermaP-hydraulic and p h y s i c a l p r o p e r t y d a t a f o r the c o o l a n t s a l t (see Task Group 9.2) f o r steam g e n e r a t o r d e s i g n needs. ,.:*

Subtask 9 . 3 . 2 . 9 - Determine e x t r u s i o n c o e f f i c i e n t and i n v e s t i g a t e o t h e r p h y s i c a l p r o p e r t i e s of c o o l a ~ n ts a l t near liquidus temperature.

A s a r e s u l t of t h e i n d u s t r i a l design s t u d i e s of stem g e n e r a t o r s (Subtask 9 . 3 . 1 . 4 ) and t h e small scale e x p l o r a t o q development work (Task 9 . 3 . 2 ) up t o t h i s p o i n t , the o v e r a l l development p l a n w i l l b e reexamined f o r H>%operdirectfan and elllpkbasis.

10.6.9

Task 9 . 3 . 3 S t e m Generator Tube T e s t Stand d e s i g n , construction, and o p e r a t i o n

The purpose s f task 9 . 3 . 3 is to establish a more f i r m u n d e r s t a n d i n g ~f t h e c r i t i c a l e n g i n e e r t n g f e a t u r e s sf molten-salt-heated steam g e n e r a t o r s .

18.6.1.1

Subtasks 9 . 3 . 3 . 1 through 9 . 3 . 3 . 8

The subtasks of t h i s task are c ~ ~ ~ c e nwith ed! 3-NhT(t) m ~ l t f ~ ~ - s aSteam lt G e n e r a t s r Tube T e s t Stand (STTS) in which three o r more full size s t e m t u b e s w i l l b e t e s t e d . These t e s t s w i l l range from e v a l u a t i o n of the thermal and mechanical stability of some design features to t h e o p e r a t i o n of some fraLB-sixe s t e m tubes in the STTS f o r evaluation of performance under full heat flux conditisns. n e Larger-scale tests r e q u i r i n g a h e a t e d c i r c u l a t i n g s a l t system would b e conducted i n t h e STTS.

A Conceptual System Design D e s c r i p t i o n of a 3-MM f a c i l i t y of this t y p e has been completed. The primary f u n c t i o n s of t h e STTS are t o : 1.

P e r f o m steady-state p a r t - and f u l l - r a t e d load testa on sPusters of full-size, f u l l - l e n g t h t u b e s i n a configuratisn r e p r e s e n t a t i v e of WSTPB-MSBW s t e m g e n e r a t o r s ,

P e ~ f o mtransient studies a s s o c i a t e d w i t h l o a d changes a t rates up t o 5%/min over t h e ran e from 20 t o 100% of f u l l load.

Demonstrate s t a r t u p of s t e m generators t h a t u s e high-meltingpoint salts f o r the heat source.

Provide a s i n g l e test facility f o r t h e e v a l u a t i o n of steam g e n e r a t o r t e s t sections front several i n d u s t r i a l f i r m .

m e power r a t i n g of 3 p16J for the test s t a n d is based on the weed t o

......

.X&

18-53 .... i.Zd

t u b e s would b e used i n the s t a b i l i t y t e s t s . '%he d e s i g n of the f a c i l i t y m y have t o b e modified t o s a t i s f y requirements r e s u l t i n g from t h e ind u s t r i a l d e s i g n s t u d i e s conducted i n Task 9 . 3 . 1 i n o r d e r t o i n c o r p o r a t e recommendations of the i n d u s t r i a l d e s i g n e r . The s u b t a s k s associated with t h e STTS are as f o l l o w s :

Subtask 9 . 3 . 3 . 1 - Conceptual d e s i g n of S t e m Generator Tube T e s t Stand (STTS)

Subtask 9 . 3 . 3 . 3 - E s t a b l i s h maintenance c r i t e r i a and develop n e c e s s a r y procedures f o r maintenance, c l e a n i n g , and i n - s e r v i c e i n s p ect i o n

Subtask 9 . 3 . 3 . 4 - T i t l e 1 and Title 11 design of the STTS

Subtask 9.3.3.5 - F a b r i c a t i o n of t h e STTS Subtask 9 . 3 , 3 . 6 - I n d u s t r i a l d e s i g n of multi-tube test assembly f o r STTS

Subtask 9 . 3 . 3 . 7 - I n d u s t r i a l f a b r i c a t i o n of test assembly for STTS Subtask 9.3.3.8 - Operation of the STTS w i t h multitube a s s e m b l i e s

10.6.8

Task 9 . 3 . 4 Model t e s t i n g i n the S t e m Generator Model T e s t I n s t a l l a t i o n (SGm%)- Subtasks 9 . 3 . 4 , B through 9.3.4.bl

Model t e s t i n g of a m o l t e n - s a l t stern generator will b e done i n test facility w i t h functisna and a size similar t o t h a t of the Sodium Components Test I n s t a l l a t i o n (SCTI) o f t h e LPgPBR Program. %faist e s t f a c i l i t y w i l l supply about 20 to 30 NW of h e a t t o a molten-salt-heated s t e m g e n e r a t o r model and will i n e l u d e all of the a u x i l i a r y s y s t e m and s u p p o r t equipment necessary t o s u b j e c t t h e ~ i ~ ~ to d e clo n d i t i o n s s i m u l a t i n g t h o s e expected i n selTfC!e* .... * B ...

... ....

Ttae test f a c i l i t y will i n c l u d e the n e c e s s a r y s a l t h a n d l i n g and c i r c u l a t i n g system, salt h e a t e r , cover gas and leak d e t e c t i o n system, o v e r p r e s s u r e p r o t e c t i o n system, s a l t d i v e r s i o n valves and system controls to a p p l y temperature rmps ana control transients, a s u p e r c r i t i c a l s t e m genepator, and a s t a r t u p system to p r o v i d e i n i t i a l coupling w i t h o u t excessive t h e r m a l shock and w i t h o u t freezing salt.

3.... 24

The stem generator model will be designed amad f a b r i c a t e d by i n d u s t r y and w i l l incorporate the results sf the design and pr-elfminary testing e x p e r i e n c e available at t h a t t h e . n e i n d u s t r i a l f i r m supplying t h e model steam g e n e r a t o r w i l l partieipate h e a v i l y i n the d e f i n i t i o n of the t e s t program and t h e development of i t s s u p p o r t i n g systems.

18-54

The 11 s u b t a s k s associated with the testing of s t e m generator models ilPe as fQIlOWS: Subtask 9.3.4.31 - Preliminary industrial clesfgn of model steam generator

- Industrial d e s i g n of model steam generatcar

Subtask 9.3.4.2

Subtask 9 . 3 . 4 . 3 - Industrial fabrication of model steam generator Subtask 9 . 3 . 4 . 4 - Conceptual design of t h e SGKlX

Subtask 9 . 3 . 4 . 5 - Title I and Title I1 design of the SGplTI

Subtask 9.3.4.7

-Performance t e s t h g of the model s t e m generator

Subtask 9 . 3 . 4 . 9 - T e s t h g sf the steam-leak detection system

Subtask 9.3.4.10

-Testing of the steam generator startup system

Subtask 9.3.4.11

- Destructive examination and final data evaluation

10.6.9

Task 3.3.5

Equipment and csntroPs criteria development

. .. w.

10-55 10.7

TASK GROUP 9 . 4

10.7.1

Objective

COVER- AND OFF-GAS

SYSTEM TECHNOLOGY DEVELOPMENT

The o b j e c t i v e of t h i s task group i s t o develop t h e technology that is needed f o r t h e d e s i @ of the cover- and off-gas system and c ~ m p o n e n t s of a m o l t e n - s a l t test r e a c t o r and for c o n f i d e n t scale-up t o a moltens a l t demonstration r e a c t o r .

18 7 2 e

Schedule

The s c h e d u l e f o r work i n t h i s t a s k group i s g i v e n i n Table 10.7.2.

18 7 * 3 c

Funding

The o p e r a t i n g fund requirements f o r t h i s t a s k group are shown i n Table 10.7.3. C a p i t a l equipment funds i n t h e amount of $40,000 w i l l be req u i r e d d u r i n g IT 1978 f o r equipment and i n s t r u m e n t a t i o n t o be used i n t h e c h a r c o a l tests (Sub t a s k 9.4 2 1) a

18 7 4

.... 4x4

,.:.>s:

... .... .... <<%

... .... ,;re

Facilities

The Gas System Technology F a c i l f t y (GSTF) and t h e Coolant-Salt Technology F a c i l i t y (CSTP) w i l l b e used f o r work in t h i s t a s k g r ~ u pd u r i n g t h e i n i t i a l phases of t h e program. These f a c i l i t i e s , which are d e s c r i b e d i n S e c t i o n s 10.4.4 and 10.5.4, w i l l b e used f o r p a r t i c l e t r a p s t u d i e s (Subtasks 9.4.1.1 and 21, BP3 management s t u d i e s (Subtask 9 . 4 . 2 . 4 ) , and removal of t r i t i u m f r o m c o o l a n t salt (Subtask 9.4.2.5).

The c h a r c o a l tests (Subtask 9.4.2.1) w i l l r e q u i r e a s p e c i a l test f a c i l i t y b u t one which should b e modest i n s i z e , complexity and c o s t . The f a c i l i t y will include charcoal-filled p i p e s equipped with heaters and temperature c o n t r o l s , a gas supply system w i t h flow controls, and p r o v i s i o n s f o r o b t a i n i n g gas samples and making r a d i a t i o n c o u n t s . The arrangement w i l l b e similar t o t h a t used previously.32 S p e c i a l t e s t f a c i l i t i e s w i l l be r e q u i r e d f o r t h e t r i t i u m and noble-gasremoval tests (Subtasks 9.4.2.2 and 3 ) . The f a c i l i t i e s w i l l b e scale medele of s y s t e m which are proposed fob" t h e m o l t e n - s a l t t e s t r e a c t o r and they w i l l b e designed as a proof t e s t of system performance. These? same f a c i l i t i e s m y also b e adapted f o r use i n performance t e s t i n g of the ~ e c y c hgas compressor (Subtask 9.4.2.6) e

10.7.5

Task 9.4.1

Handling of n o n - v o l a t i l e c o n s t i t u e n t s

me o f f g a s stream from t h e r e f e r e n c e M S B R ~primary ~ system will c o n t a i n m i s t s o r smokes a t r e l a t i v e l y low c o n c e n t r a t i o n (probably somewhere between 100 and 1000 ppm by volbume) and c o n s t i t u t e d as f o l l o w s :

Table

3.4.1

Nm-volatile 9.4.1.1 9.4.1.2 9.4.1,3

10.7.2.

Schedule

for

csnatituents Fuel system particle CmPamt system particle Non-volatile fission diEpX3d

work

trap trap product

Task

Group

9.4

- Cover

amd off-gas

system

te&nology

Fiscal

year

deve3bopent

Table

10.7.3.

Qperating

fund

requirements for Task Group 9.4 - Cover (costs in 1880 dollars)

1976 9.4.1

9.4.2

Non-volatile constituents trap 9.4.1.1 Fuel system particle 9.4.1.2 Coolant system particle trap 9.4.1.3 Nan-volatile fission product disposal Subtotal

9.4.1

Volatile 9.4.2.1 9.4.2.2

9.4.2.6

sonstituents Charcoal bed tests Removal sf tritium from fuel offgas Removal of 85Kr BF3 recycle Removal of tritiwm from coolant offgas Recycle gas compressor

Subtotal

9.4.2

operating

funds

9.4.2.3 9.4.2.4 9.4.2.5

Total.

for

Task Group 9.4

1977

1973

1979

50 03

120

4Q 60

and off-gas

Fiscal

year

1981

system

1982

1983

1984

18 1Q

20 20

3.8 PQ

20 28 48

30 3Q

20 2Q 20

40 1QQ 20

28 38 20

8Q 80

18Q 186)

20 10

100 118

1985

Fuel salt particles, generated in the pump bowl and %he bubble separator9 having potential s i z e s ranging from 1 to 10 microns.

thhougkt 52Te) An estimated3' 1% to 58% of the noble metal fission gro%UctS 8s p a r t i c l e s ranging i n size from 0.81 to 10 u . For a 225Q-BW(t) reactor, the mass flow rate could b e as high as 308 grams p e r day.

~On-Vohtile fiS§iOn prodbnct dabngtaters of Kr and me aEiSUIlption is made that noble gas daughters which are born in the salt will b e retained in the s a l t as fluorides. For a 2200-MW(t) reactor, and assuming a 2-hora-p gas Esc~ldupV Q ~ U I E ~an , estbated 148 grams per day uf noble-gas daughters will b e f s m e d in t h e primary salt: d r a i n tank.

The off-gas stream from the coolant salt system is expected ts contain s a l t m i s t particles in about the same size range and concentration as the fU@l syStC3R Off-gaS. HQWE!VerK, the cOEl~oSitiOnsf the Salt Will be d i f f e ~ e n tand there will be no fission products, no radioactivity ( e x c e p t f o r some short-lived induced activity), and no decay heat.

l8.7.5.l

Subtask 9.4.1.1.

K.3

P a r t f C l @ t r a p f o r fete1 System Off-gaS

In the MSBR reference d e s i nr31 a p a r t i c l e trap may be required at the outlet s f the fuel s a l t drain tank. A p a r t i c l e trap will not be required if the drain tank serves as an efficient particle trap. $he objective of this task is t o develop the technology related to the removal sf particles by the d ~ a i ntank to the point where a firm decision can be made regarding t h e need f o r a particle trap. The initial approach will b e t o assume that the Gas-System Technslogy F a c i l i t y (GSW) is representative of a reactor system. The rate of s a l t mist carryover from the GSTF d ~ a tank h will be measured and, if p ~ s s i b l e , t e s t s w i l l be devised to Study the Ca%PgroVe%Of b18ble metals and Roble-gctS daughters. If the test results i n d i c a t e t h a t solids carryaver will be a problem and that a particle trap will be required, work will be initiated on p a r t i c l e t ~ a p concepts and any accompanying experimental effort which might be indicated.

"Phe initial objective u f this task is t o examine %he problem of soslantsalt m i s t carryover and t o determine whether a particle trap will be required. If a t r a p is required, criteria will be established for i t s design. I n p u t data fok the evaPraatis~and d e s i g n w i l l be obtained from the operating experience with the CSTF off-

10-59

The o b j e c t i v e of t h i s task i s to determine an a c c e p t a b l e procedure f o r d i s p o s i n g sf s o l i d f i s s i o n p r o d u c t s which accumulate i n the c h a r c o a l beds o r o t h e r p a r t s of t h e off-gas system.

10.7.6 ....

I<M

Task 9.4.2

Handling of v o l a t i l e c o n s t i t u e n t s

%e off-gas stream from b o t h t h e fuel system and the c o o l a n t system of t h e r e f e r e n c e M S B R ~will ~ c o n t a i n v o l a t i l e c o n s t i t u e n t s which w i l l pres e n t management (3F d i s p o s a l problems. Sihe f u e l System o f f g a s Will cont a i n r a d i o a c t i v e krypton and xenon as w e l l as tritium. This gas w i l l b e passed through c h a r c o a l d e l a y beds t o allow t h e decay 0% s h o r t - l i v e d i s o t o p e s , a f t e r which t h e Kr-85 and tritium would b e placed i n a s a t i s f a c t o r y form f o r d i s p o s a l . The coolant-system o f f g a s w i l l contain BF3 and tritium which must b e p l a c e d i n a form a l l o w i n g d i s p o s a l .

10.7.6.1

Subtask 9.4.2.1

Charcoal bed holdup test f o r f u e l system o f f - g a s

The r e f e r e n c e d e s i g n MSBW i n c l u d e s a c h a r c o a l d e l a y bed through which t h e f u e l system off-gas p a s s e s . P a r t s of t h e d e l a y bed system o p e r a t e a t temperatures as high as 258°C. The e f f l u e n t g a s , a f t e r s u i t a b l e cleanup, is r e c y c l e d t o the purge gas supply system. Adsozrpeion c o e f f i c i e n t d a t a w i l l b e determined e x p e r i m e n t a l l y f o r t h e expected o p e r a t i n g temperature range i n ~ i d e rt o augument t h e p r e s e n t d a t a which extend t o o n l y 1QO'C. Also, tests w i l l b e wade t o determine t h e e f f e c t on t h e a d s o r p t i o n CQe f f i c i e n t of s o k k h d e p o s i t i o n r e s u l t i n g from f i s s i o n produet decay. A s t u d y w i l l b e made t o determine what procedures w i l l b e n e c e s s a r y t o h a n d l e adsorbed materials such as oxygen amd water which might b e p r e s e n t i n t h e as-received c h a r c o a l . AEsQ, t h e thermal s t a b i l i t y of ~ h a r c o a lw i l l b e e x m i n e d t o determine whether o p e r a t i o n a t 250°C c a u s e s e v o l u t i o n of o r g a n i c materials o r d e g r a d a t i o n of p h y s i c a l p r o p e r t i e s . For determining t h e a d s o r p t i o n c o e f f i c i e n t s , a test s e t u p s i m i l a r t o t h e one used f o r making t h e Pow temperature t e s t s a 2 w i l l b e r e q u i r e d . By a l s o adding t h e n e c e s s a r y sampling o r analytical equipment, t h e same syst e m can b e used f o r t h e cleanup and thermal s t a b i l i t y t e s t a .

10.7.6.2

Subtask 9.4.2.2

R e m o ~ a lsf tritium from f u e l system off-gas

I n t h e r e f e r e n c e d e s i g n MSBR, tritium i n t h e f u e l system off-gas w i l l be r e a c t e d w i t h hot CuO t o f ~ f - a n t r i t i a t e d w a t e r which w i l l b e i s o l a t e d by means of a r e f r i g e r a t e d a d s o r b e n t . The technology f o r t h i s p ~ o c e s si s w e l l e s t a b l i s h e d and e x p e r i m e n t a l work w i l l b e l i m i t e d t o p r o o f - t e s t i n g of t h e method i n a mockup of t h e system.

18-60

10.7.6.3

Subtask 9 . 4 . 2 . 3 Removal of Kr-85 and s t a b l e K r a d X e from f u e l system off-gas

A 2250-l?lW(t) reactor will produce about 60 l i t e r s p e r day of KK-85 p l u s s t a b l e Kr and We. mis material, a l o n g w i t h t h e t r i t i a t e d water ( s e e previous section) will be i s o l a t e d by means o f a r e f r i g e r a t e d a d s o r b e n t . The t e ~ h ~ i h gfor y t h i s process i s w e l l e s t a b l i s h e d and e x p e r i m e n t a l work w i l l be limited to p r o o f - t e s t i n g of t h e method in a mockup of t h e system. %e mockup would b e designed t o d ~ ~ ~ ~ ~t h e~ performance t r a t e and r e l i a b i l ity of: t h e CuO r e a c t o r for tritium o x i d a t i o n a d the refri e ~ a t e c iadsorb e n t and l i q u i d - n i t r o g e n t r a p f o r iso1atPng t h e noble g a s e s and t h e t r i t i a t e d water#

10.7.6.4

Subtask 9 . 4 . 2 , 4

Management of BP3 i n c o o l a n t s y s t e m off-gas

Methods w i n b e d e v e l ~ p e df o r safe and ecornomica~management 0% B P ~in t h e coolant wver- and off-gas system. This s u b t a s k would i n c l u d e design a d experimental work needed t o develop a BF3 r e c y c l e system. I n p u t d a t a eriemce w i t h the BP3 f o r t h i s task w i l l b e o b t a i n e d through o p e r a t i n g econornrbzer which i s i n s t a l l e d $n t h e GSTF.

10.7.6.5

Subtask 9.4.2.5

Removal of tritium from c o ~ l a n tsystem off-gas

About 2580 c u r i e s p e r day of tritium w i l l b e produced i n a %%58-MW(t) m o l t e n - s a l t r e a c t o r . A l a r g e fraction sf t h i s gas i s expected t o be tPanspQKted from the f u e l system i n t o the c o o l a n t system. A method Will be developed for h a n d l i n g and d i s p o s i n g of t h e tritium which i s t r a n s p ~ t e dinto t h e c o o l a n t s a l t o f f - g a s system. Work i n t h i s s u b t a s k will be c l o s e l y c o o r d i n a t e d w i t h the previous s u b t a s k ($Pa management) t o e n s u r e t h a t t h e r e s p e c t i v e approaches are compatible. "he approach to t h i s problem m y b e s t r o n g l y a f f e c t e d by information developed i n the d e u t e r h m - i n j e c t i o n tests (Subtask 9 . 2 . l . 2 ) and r e l a t e d work. 10.7.6.6

Subtask 9 . 4 . 2 . 6

Recycle-gas

compressor

The r e f e r e n c e d e s i g n bgSBR s p e c i f i e s that t h e p r i m ~ ys y s t e m off-gas w i l l be ~ e ~ o m p r e s s eand d r e u s e d as purge gas f o r t h e primary system. me o b j e c t i v e of t h i s s u b t a s k i s to p r o v i d e t h e e n g i n e e r i n g e f f o r t needed t o i d e n t i f y a c o m e ~ c i a l omp pressor, o r develop a compressor which w i l l do ghe job effectively and r e l i a b l y without contaminating t h e pumped f l u i d w i t h wet a i r o r o t h e r materials. Design c r i t e r i a w i l l be e s t a b l i s h e d a f t e r which the a v a i l a b i l i t y s f comerical units will be determined.

The o b j e c t i v e s of this t a s k group i n c l u d e t h e development of t h e techms%ogy necessaT?j f o r d e s i g n 0% s h o r t - s h a f t salt pump8 for m s l t e n - s a l t t e s t and demonstration r e a c t o r s and the procurement and t e s t i n g of fullscale p r o t o t y p i c a l pumps f o r t h e t e s t and demonstration r e a c t o r s . It is recognized t h a t i n d u s t r i a l p a r t i c i p a t i o n via ORNL s u b c o n t r a c t o r industry-supported d ~ ~ e l o p m ies~ an t important f a c t o r , and a p p r o p r i a t e measures will b e taken to e n s u r e that t h i s i n p u t w i l l b e forthcoming. h o t h e r o b j e c t i v e i s the 5 n v e s t i g a t i o n sf s a l t - l u b r i c a t e d bearings, and their development t o a p o i n t t h a t a long-shaft p r o t o t y p e pump can b e designed 0

To t h @ e x t e n t p o s s i b l e , the pumps r e q u i r e d f o r t h e m o l t e n - s a l t test r e a c t o r will b e t h e same as t h o s e to be used i n t h e demonstration reactor i n order that the rider of p r o t o t y p e s a l t p u m p t o be developed will be Kdnifai2ed.

10 * 8 * 2

..-

Schedule

The s c h e d u l e for work i n t h i s t a s k group i s shown i n Table 10.8.2. Work on t h e s h o r t shaft pump w i l l s t a r t as soon as pump requirements have been determined i n 1978. The s p e c i f i c a t i o n s would b e completed, and r e q u e s t s for i n d u s t r i a l b i d s would be i s s u e d i n FY 1978. A f t e r b i d e v a l u a t i o n , c o n c e p t u a l d e s i g n by i n d u s t r y of the MSTR p r o t o t y p e pump would b e started i n F" 1979. Detail d e s i g n w i l l start i n 1988, and c o n s t r u e t i o n I n FY 1981. D e l i v e r y 0% a p r o t o t y p e pump would b e expected by the end sf E T 6983. me design of t h e pump test stand f o r the compon e n t s T e s t Facility would s t a r t in '%j"II 1979, which would b e sufficiently early f o r t h e t e s t s t a n d t o b e ready by the tfme t h e pump arrives, Pump t e s t i n g w2P% start in m 1983.

Tke development of molteaf-salt-laa~f.ieatedb e a r i n g s f o r a long-shaft pump

&I1 b e s t a r t e d i n FY 1980 in case t h e d e s i g n i n d i c a t e s an advantage ts u s i n g t h i s t y p e pump. If this o c c u r s , a d d i t i o n a l work w ~ u l db e required to develop this p u p type.

Operating fund ~ ~ p i ~ ~for ~ the t ~ tn a s kt group s are shorn in 'Fable 10.8.3. The largest expense i t e m 5s a s s o c i a t e d w i t h t h e d e s i g n and c o n s t r u e t i o n sf the prototype p m p . A u t h o r i z a t i o n O f funds ($1million) f o r t h e d e s i g n and e o n s t r u e t i o n of the S a l t Pump T e s t Stand will b e r e q u i r e d i n FY 1980.

1 (4 8 4 0

Facilities

Most of the development will b e done in t h e S a l t Pump T e s t Stand i n the Components T e s t F a c i l i t y Qlo.lz>,

9.5 .I

Short 9.5.1.1 9.5.f.2 9 .T -1.3 9.5.1.4 9.5.1.5 9.5.1.6 9.5.1.7

9 e 5.2

shaft

pap devdopment MSTR gnAgg;jlKy pump

specifi-

Evaluation of pkoposak3 Industsial design of FfSTR prototype pump const%uctlon of MSTR prototype pump Design pump test stand construct.ion of pump test stand Msm prototype pump tests

Salt-luhsicated 9.5.2.1 Review 9.5.2.2 Bearing

b@aKing deve~aplemt technolsgy development

Table

10.8.3.

Operating

fund

requirements (costs

1977 9.5.1

Short shaft pump development 9.5.1.1 MSTR primary pump specifications and RFP 9.5.1.2 Evaluation a% proposals 9.5.1.3 Industrial design of MSTR prototype pump 9.5.1.4 Construction of MSTR prototype pump 9.5.1.5 Design pump test stand 9.5.1.6 Construction 0% pump test stand 9.5.1.7 MSTR prototype pump tests Subtotal.

9.5.2

Total

9.5.1

for work in Task Group 9.5 - Salt in 1080 dollars)

1978

Fiscal

year

19 80

19 a

1982

1983

560

760 900

700 25

1200

1225

1979

9.5.2

operating

fmds

%or Task Group 9.5

1984

1985

150 1075

300 300

___ 1075

300

40 40

140

585

1485

Salt-lubricated bearing development 9.5.2.1 Review technology 9.5.2.2 Bearing development Subtotal

pump development

140

40 625

1986

10 8.5 2 e

After a l l t h e bids have been received they will be thoroughly analyzed to e~1su1-e t h a t the desired design procedures will be carried out. 10 8.5 3 a

This subtask w i l l involve b o t h conceptual amd f i m a l p r s t o y p e p m p design and will %nelbade independent review and approval.

......... g<+:

10* 8.5 * 4 h e o r more p r o t o t y p e pumps w i l l be co~structedby one or ITIOK~ qualified vendors w i t h periodic consultations and inspections by an independent reviewer.

l o 8* 5.5 0

Facility

A preliminary d e s i g n d e s e r f p t i s n f o r a p u p test stand f o r an MSBE size pump w a s written in 1969. This information w i l l be the b a s i s f o r the design of t h e pump t e s t stand in the Components Test F a c i l i t y .

PQ.8.5.6

Subtask 9.5.1.6 T e s t Facility

Construct pump t e s t stand in the Csmpsments

This s u b t a s k covers the construction sf the pump test stand and installation of the prorotype pump.

10.8.5.9

Subtask 9.5.1.7

T e s t p r o t o t y p e pump

Some of the t e s t s to b e done in t h e punp test s t a d are listed below:

h..

Obtain the pump h y d r a u l i c perforatance and c a v i t a t i o n i n c e p t i o n c h a r a c t e r i s t i c s over a wide range of pump speeds, c a p a c i t i e s , and temperatures.

Determine t h e s t a r t u p and coastdown c h a r a c t e r i s t i c s of t h e pump a d d r i v e motor under l o a d esnditions.

Deterndne t h e c h a r a c t e r i s t i c s of the purge gas flow i n the s h a f t annulus s

Determine t h e d i s t r i b u t i o n of s a l t a e r o s o l s produced by pump o p e r a t i o n and o b t a i n t h e perfomance c h a r a c t e r i s t i c s of a e r o s o l removal d e v i c e s , i f n e c e s s a r y .

Demons trace t h e o p e r a b i l i t y of t h e i n c i p i e n t f a i l u r e d e t e c t i o n (ID) d e v i c e s .

Obtain long-term endurance operation w i t h p r o t o t y p i c pumps.

Make m o l t e n - s a l t proof tests of advanced i n s t r u m e n t a t i o n f o r m o l t e n - s a l t systems as i t becomes a v a i l a b l e .

10.8.6

Task 9.5.2

18.8.6.1

Development of ~ o l t e n - s a l t - l u b r i s a t @ d b e a r i n g s

Subtask 9.5.2.1

S t a t u s of technology r e p o r t

mi8 s u b t a s k will i n v o l v e a l i t e r a t u r e s e a r c h and c o n s u l t a t i o n s w i t h W H R p e r s o n n e l and w i t h Plechanical Technology, Inc. personnel i n o r d e r t o determine and samrmnarize the s t a t u s of d e v e l o p e n t of bong-shaft pumps f o r m o l t e n - s a l t s e r v i c e . 10.8.6.2

Subtask 9 . 5 . 2 . 2

Define and perform development program

Based on t h e technology r e p o r t , a d e t a i l e d development program w i l l b e o u t l i n e d and c a r r i e d o u t which w i l l p r o v i d e i n f o r m a t i o n n e c e s s a r y f o r t h e d e s i g n of l a r g e scale l o n g - s h a f t pumps. C u r r e n t i n f o r m a t i o n indicates t h a t this w i l l i n c l u d e f a b r i c a t i o n of long shafts to p r e c i s e c o n c e n t r i c i t y , s t r a i g h t n e s s , amd dynamic b a l a n c i n g , as w e l l as providi n g mechanical d e v i c e s t o accommodate t h e r e l a t i v e l y l a r g e d i f f e r e n t i a l t h e m 1 expansion that o c c u r s between a s h a f t and bearfng s u p p o r t eons t r u c t e d of H a s t e l l o y N and j o u r n a l s and sleeves c o n s t r u c t e d of r e f r a c t o r y m e t a l s o r cemented c a r b i d e s having s m a l l e r c o e f f i c i e n t s of thermal g;spansi o n .

18-64

10.9

TASK GROUP 9 . 4

P R L W Y SALT-SALT HEAT E2XXANGm DEVELOmEW

18 3 *I 0b-jeetive The objective of this task group is to develop the technology which will allow detailed design of a primary heat exchanger f o r the molten-salt test reactor. Ffnab optimization of heat exchanger design to mirmFmize fuel salt inventory for the molten-salt demonstration reactor and MSBR will be done after tests in the molten salt test reactor.

10.9.2

Schedule

As indicated in Table 10.9.2, the status of t ~ ~ h n o l oreport m should be T 1981, and development work finished in FY 1983. completed in l

10.9.3

PundFng

Operating fund requirements for this task group are shown in Table 10.9.3. The higher r a t e of spending in FY 1983 is associated w i t h proof testing fop the molten-salt test reactor. Capital equipment funds of $50,000 w i l l be required during 1982 for modification of the G S p and CSTF to allow heat exchange studies.

18.9.4 Facilities Some of t h e early work in this task group will be done in %he CoolantS a l t TeehnoloO Facility (CST??) ( 1 0 . 5 . 4 ) and Gas-SystemS Teehnsloggr Facility (GSTF) (10.4.4) with later development in the Components T e s t

Facility

10.9.9

Task 9.6.1

Status of tecknolbopy report

A P i t e ~ a t u r esearch w i l l be carried out: with special emphasis on recent enhanced tube development work which would reduce the required heat transfer surface area and the fuel s a l t inventory requirements.

10.9.6

Task 9 . 6 . 2

Define and p e r f o m development program

Based on the technology report, a development program w i l l be o u t l i n e d and carried sut to obtain the additional technology necessary f o r design of a primary heat exchanger for the molten-salt test reactor. Small scale heat transfer studies w i t h enchanced tubes will be made in the ~J and Gas-System Technology Facility. Coolant-Salt T C X ~ ~ O E Q Facility Tlae effect of gas voids on heat transfer will be studied in the latter.

b,..

Table 10.9.2

Table 10.9.3.

Schedule f o r work i n Task Group 9 - 6 - P r i m a r y s a l t - s a l t h e a t exchanger development e

Operating fund requirements f o r Task Group 9.6 - P r i m a r y s a l t - s a l t heat exchanger development ( c o s t s i n 1000 d o l l a r s ) Fiscal year 1988

1981

~~~

9.6.1

9.6.2

R e v i e w technology and d e f i n e program

Heat t r a n s f e r studies

Total Operating funds f o r Task Group 9 . 6

1982

$983

1984

PO-68

Tke Molten-Salt eactor E x p e r b e n t used no valves in s a l t i n t h e r e a c t o r primary system and only small f r e e z e v a l v e s i n t h e d r a i n l i n e and i n t h e d r a i n t a n k system. Larger freeze valves and/or mechanical valves f o r use i n s a l t will b e needed f o r m o l t e n - s a l t b r e e d e r r e a d t o r s .

18 * 10 k

S b j eetive

EO.lQ.2

Schedule

1 8 kO 3

Funding

Operating fund requirements f o r t h i s t a s k group are s h o w i n Table 10.10.3. C a p i t a l equipment funds i n t h e amount sf $250,000 will b e r e q u i r e d i n FY 1979 f o r d e s i g n and ~ ~ n s t r u ~ t iof o nthe Valve T e s t Facility 0

a 8 16 4 e

Facilities

%%neCoolant-Salt Technolsgy Facility and the Gas-System Technology F a c i l i t y w i l l b e used f o r some o f the e a r l y valve development work; however a separate s m a l l f a c i l i t y i s needed f o r u s e i n making p r e l i n i n a r y tests on mdels o r p r o t o t y p e s of r e a c t o r v a l v e s . % i s f a c i l i t y , ~ ~ O WasR the Valve T e s t Facility, w i l l c o n s i s t of several s u p p l y vessels and d r a i n vessels f o r c o n t a i n i n g molten salt a t temperatures t o 75O"C, essential auxiliaries, test stands on which the equipment w i l l b e mounted, a housing around each test s t a n d , and a cornon v e n t i l a t i o n system. For t e s t i n g , a valve will b e i n s t a l l e d i n t h e p i p e betseen a supply vessel and a d r a i n vessel. Transfer of s a l t between the vessels will b e e f f e c t e d by a d j u s t i n g t h e cover gas p r e s s u r e s . me vessels, p i p i n g , ana v a l v e s will be heated e l e c t r i c a l l y and w i l l b e h e a v i l y i n s u l a t e d . A i r c o o l i n will b e provided for some sf the t a n k s . The tests on the valves will include d e t e r m i n a t i o n of l e a k a g e rates under v a ~ - i o u sc o n d i t i o n s of temperature and p r e s s u r e and h v e s t i g a t i o n of t h e e f f e c t s of thermal t r a n s i e n t s and thema1 c y c l i n g on

k..<

Table

10.10.2.

Sc2hedul.e

for

wmk

Task

Group

9.7

-Valve

Group

9.7

development

program 9.7.2

Valve

Table

development

Operating

10.10.3.

fund

requirements for Task (cost in 1(300 dollars)

Fiscal 1977 9.7.1 9.7.2

Review program

technology

Valve

develspment

Total operating Group 9.7

1978

- Valve

develsgment

year

1979 .

19 80

19 81

1982

1983

19 84

100 cp

BOO -

100 _I_

il.00 -

100 __

200 --

100

1QO

IQ0

1QQ

loo

2QQ

and define 40

funds

for

Task

1985

10-70

the Valves. The f a c i l i t y Will i n c l u d e t h e inStrUXQelltatiQn and control% necessary f o r operation of the equipment b u t no special instrumentation

for obtaining t e s t data. Cover gas will be supplied from a system cornon to several. facilities and the off-gas will be d i s c h a r g e d to a common off-gas system. The valves used in t h e t e s t s will be provided by the valve development activity. F i n a l testing of larger size valves will be done in the Components Test Facility (lS.%3> and the m ~ l t e n - s a l l t test reactor mockup (see Section 13). 10.10.5

Task 9-7.1 Status of technology report

This task will involve a literature search and consultation with valve mwufacturers and LNFBW personnel to establish present state-of-the-art f o r high temperature valves and operators as well as a detailed evalua%iota of eXpeKiemfCe W i t h free%eValves fn the ?dSR PTBglpaDl.

10.LQ.6 Task 9.7.2

Define and p e r f s m development program

~ a s e dOn t h e technology report, a aetaiied development program will b e s u t l i n e d . Design and C O ~ S ~ P U Csf~ t~h e~ R Valve Test Facllity will b e completed, and work on valve development w i l l be carried out. Two mjor uncertainties related to valve development involve selection of the p l u g and seat materials and design and development of high temperature opera t o r s . The fabrication of reliable b e l l o w s O K some o t h e r hermetic stem s e a l , such as t h e t ~ ~ r q u e - t ~ sbega l , must b e demonstrated, A CQTlllnt?riCa% e a p a b f l i t y f o r f a b r i c a t i n g large Hastekaoy valves would be developed.

Control r o d s t h a t have been conceived f o r molten-salt breeder K ~ ~ C ~ O I - S represent a m r k e d d e p a r t u r e from present technology. h Q%let m e , the active section is of graphite, in another it is of m e t a l . In b o t h types, t h e active section operates in h i g h l y radioactive fuel salt at temperatures ts 756'C, but the directly coupled r o d drtves must sperate at temperatures below about 200°C.

18 11 1 Obj ee t i v e e

10-71 B0.ll.2

Schedule

The s c h e d u l e for t h e development of c o n t r o l r o d s f o r MSB’s is shown i n Table 1 0 . 1 l . 2 . A s t a t u s of technology r e p o r t and t h e c o n c e p t u a l d e s i g n of the Control Rod T e s t F a c i l i t y w i l l b e completed i n ET 1981. F i n a l d e s i g n of t h e f a c i l i t y w i l l b e completed i n FY 1982, and c o n s t r u c t i o n of t h e f a c i l i t y w i l l b e completed d u r i n g ET 1983. The major p o r t i o n of t h e development e f f o r t w i l l b e done i n c o n j u n c t i o n w i t h t h e d e s i g n of t h e m o l t e n - s a l t t e s t r e a c t o r which w i l l b e g i n i n FY 6985.

10 Pa.. 3

Funding

Operating f u n d ’ r e q u i r m e n t s f o r t h i s t a s k group are shown i n Table 10.11.3. C a p i t a l equipment funds i n the m o u n t of $250,000 w i l l b e T 1982 f o r d e s i g n and c o ~ s t ~ u c t i oofn t h e C o n t r o l required during I Rod T e s t F a c i l i t y .

18.11.4

Facilities

A s noted e a r l i e r 9 the c o n t r o l rods lpr~poseclf o r t h e HSBR are markedly d i f f e r e n t from p r e s e n t technology, and a f a c i l i t y w i l l b e r e q u i r e d f o r t e s t i n g p r o t o t y p e s of KSR-type rods and d r i v e s in a s i m u l a t e d r e a c t o r environment. No f a c i l i t y exists where such tests could b e made, and i t w i l l b e n e c e s s a r y to c o n s t r u c t a r o d - t e s t f a c i l i t y .

......

i .m ,

..... ..... :.:.a

%he Control Rod T e s t F a c i l i t y w i l l c o n s i s t p r i m a r i l y 0% a rod test t h i m b l e , a small m o l t e n - s a l t c i r c u l a t i o n system and e s s e n t i a l a u x i l i a r y systems, a t e s t s t a n d OR which t h e equipment w i l l b e mounted, a housing around t h e test s t a n d and a v e n t i l a t i o n system. The rod t e s t thimble will sfmulate t h e r e a c t o r vessel and upper s h i e l d s t r u c t u r e . Molten s a l t w i l l b e rec i r c u l a t e d through a rod channel formed by g r a p h i t e p i e c e s i n t h e Power section of the thimble. The r o d w i l l be moved in t h e rod channel by a d r i v e mounted in the upper s h i e l d s e c t i o n of t h e thimble. A p p r o p r i a t e seals i n t h e upper shfeld s e c t i o n w i l l p r o v i d e t h e n e c e s s a r y s e p a r a t i o n between t h e environments of t h e rod and t h e d r i v e . The r e a c t o r s e e t l o ~ ~ of t h e thimble and t h e s a l t c i r c u l a t i o n system w l l l be h e a t e d e l e c t r i c a l l y and w i l l b e h e a v i l y i n s u l a t e d . A c o o l i n g system w i l l be provided f o r t h e upper s h i e l d s e c t i o n of t h e thimble. A d r a i n tank w i l l b e provided f o r t h e s a l t . Cover gas w i l l b e s u p p l i e d from a system cornon t o several f a c i l i t i e s , amd t h e off-gas will b e d i s c h a r g e d to a cornon off-gas system. Am i n s t r u m e n t a t i o n and c o n t r ~ lsystem w i l l b e provided for t h e test f a c i l i t y . The ControE sods and drives and t h e i r i n s t r m e n t a t i o n and c o n t r o l s w i l l . b e provided by t h e C O ~ ~ K Qrod B development a c t i v i t y .

Table 1Q.U.2.

Schedule for work in Task Grmp 9.8 - Control ma development --Fiscal year ,-. 1.981 1982 j 1983 1980 19 84 1985 19$6

10-73

10.11.5

Task 9.8.1

Define development program and c o n s t r u c t test f a c i l i t y

Most of t h e work on d e v e l ~ p m e n tof c o n t r o l and s a f e t y rods w i l l b e d i r e c t e d Coward t h e needs f o r t h e m o l t e n - s a l t test reactor. The work i n this task w i l l be concerned with p r e p a r i n g a s t a t u s of technology r e p o r t , d e f i n f n g a c o n t r o l rod development program, and completing t h e d e s i g n and c o n s t r u c t i o n of t h e C o t l t r ~ lRod T e s t F a c i l i t y . There has been no e x p e r i e n c e w i t h c o n t r o l rods o p e r a t i n g d i r e c t l y in salt t b e deand problems O f p h y s i c d arrangemnt, Cooking and C O n t a h n ~ ~must veloped. Drive mechanisms developed f o r t h e W B R program p o s s i b l y could be adapted f o r use i n t h e MSBR contra% d r i v e system. The “rol1er nutss concept as d e p i c t e d by t h e Marvel % s h e b i e r d r i v e by Borg Warner and t h e If magnetic jack” d r i v e by Westinghouse are p o s s i b i l i t i e s w h k h would be considered because of t h e d e s i g n and development a l r e a d y accomplished i n support of t h e LMFBR program.

10.11.6

Task 9.8.2

P e r f o r m development program

Most of the work i n t h i s task w i l l b e a s s o c i a t e d w i t h development o f t h e d r i v e mechanism and methods for g u i d i n g t h e r o d s . S h i e l d i n g and c ~ n t a i n ment will also b e c o n s i d e r e d .

10.12

TASK GROUP 9 . 9

10.12.1

Objectives

CBNTAIMENT AND CELL HEATING

The o b j e c t i v e o f t h i s task group is to p r o v i d e sufficient testing Sf the proposed oven-type h e a t i n g of the s a l t - c o n t a i n i n g system t o determine t h e c o n s t r a i n t s which t h i s approach places on maintenance, operat i o n , and i n s t r u m e n t a t i o n s e l e c t i o n , and to compare i t s econ~slticimpact w i t h that of other containment and equipment h e a t i n g methods. 10.12.2

Schedule

A s i n d i c a t e d on Table l Q . l 2 . 2 , t h e d e f i n i t i o n of the development program is d i v i d e d into ~ W Qp e r i o d s , one i n F T 1980, and t h e o t h e r i n IFII 1984. T%e f i r s t period c o v e r i n g FY 1981 and 1982 i s f o r o b t a i n i n g b a s i c d a t a needed f o r d e s i g n . The work i n FP 6985 i s i n t e n d e d tQ t e s t detailbed d e s i g n of t h e primary containment f o r the m o l t e n - s a l t t e s t r e a c t o r .

10.12 3 e

.:&

Funding

Operating f w d requirements for t h i s t a s k group are g i v e n in Table 10.12.3. These f i g u r e s , e s p e c i a l l y t h o s e shown in FY 1984 and 1985, should be considered p r e l i m i n a r y . C a p i t a l e q u f p m n t funds i n t h e anount of $77,000 will b e r e q u i r e d d u r i n g F”9 1981.

Table lQ.12.2.

Schedule for work in Task Graup 9.9 - Containment and eel1 heating ----

9 *9 .I. Define development program

Table

10.12.3.

Operating and cell

cost requirements heating (casts

1979 9.9.1

Define

development

9.9.2

Carry

out

Total

operating

program

development costs

for

19 80

Group

19 81

9.9

- Containment

Fiscal

year

1982

1983

work Task

for Task Group BOQQ do%lars)

1984

1985

100 lQ0 108

68 60

100

50 .50

1986

18-75 16.12.4

Facilities

P r e l i m i n a r y development of v a r i o u s i t e m s w i l l b e done on an i n d i v i d u a l b a s i s b u t t h e oven-type h e a t i n g and containment system w i l l b e t e s t e d i n t h e m o l t e n - s a l t t e s t r e a c t o r mockup (see S e c t i o n 1 3 ) .

18.12.5

Task 9 . 9 . 1

Define development program

Although t h e containment philosophy and t h e i d e a of u s i n g t h e c e l l as a n oven a p p e a r s s t r a i g h t forward, t h e s e need t o b e s t u d i e d c a r e f u l l y i n o r d e r t o uncover any u c e r t a i n t i e s and t o d e f i n e a program to r e s o l v e t h e s e . The KTGW e x p e r i e n c e w i l l b e f u l l y u t i l i z i e d .

10.12.4

Task 9 . 9 . 2

Perform development program

This t a s k i n v o l v e s t h e accomplishment o f t h e work o u t l i n e above. .... e.=

10.13

TASK GROUP 9.10

10.13.1

Qbjectives

COEPQNENTS TEST FACILITY

The o b j e c t i v e of t h i s t a s k group i s t o p r o v i d e a l o c a t i o n equipped w i t h t h e n e c e s s a r y s e r v i c e s and u t i l i t i e s t o permit development and t e s t i n g of l a r g e - s c a l e r e a c t o r camponerats and systems under d e s i g n c o n d i t i o n s as w e l l as unusual o p e r a t i n g c o n d i t i o n s . A 30-MW MSR steam g e n e r a t o r model w i l l be t e s t e d which w i l l produce steam a t temperatures and press u r e s proposed f o r t h e t e s t r e a c t o r . Information w i l l b e o b t a i n e d on v a r i o u s items i n c l u d i n g t h e s t a r t u p procedures, t h e o v e r p r e s s u r e prot e c t i o n system, and t h e steam-leak d e t e c t i o n system. A p r o t o t y p e pump w i l l b e t e s t e d t o o b t a i n i n f o r m a t i o n on f a c t o r s i n c l u d i n g t h e flow c h a r a c t e r i s t i c s and t h e e f f e c t s s f temperature t r a n s i e n t s . Large-scale valves, c o l d traps, core components, heat exchangers, t r i t i u m management schemes, e t c . w i l l b e t e s t e d under a l l c o n d i t i o n s which are l i k e l y to b e encountered i n an o p e r a t i n g r e a c t o r . Development of some components w i l l b e c a r r i e d o u t c o n c u r r e n t l y i n a s i n g l e development f a c i l i t y , w h i l e o t h e r s w i l l require individual f a c i l i t i e s . T h i s work cannot b e done i n e x i s t i n g f a c i l i t i e s , due t o t h e Parge s p a c e requirements. For i n s t a n c e , t h e s t e a m g e n e r a t o r model w i l l b e about 145-ft h i g h , a 3 0 a s a l t h e a t e r w i l l b e needed, and l a r g e c o o l i n g towers w i l l be required f o r a heat sink.

:.:=

The CTF is i n t e n d e d p r i m a r i l y f o r t h e development and t e s t i n g o f compon e n t s a s s o c i a t e d w i t h t h e t e s t r e a c t o r . However, t h e f a c i l i t y d e s i g n w i l l b e such t h a t i t could b e modified o r expanded f o r u s e i n a d d i t i o n a l . component development f o r a demonstration r e a c t o r .

Although some components t o b e t e s t e d i n t h e C o q o n e n t s T e s t F a c i l i t y w i l l b e f u l l scale, a d d i t i o n a l p ~ o ~ f t e s t i n of g all c ~ m p ~ n e n w t si l l b e c a r r i e d out i n t h e m o l t e n - s a l t t e s t reactor mockup. T h i s system w i l l b e a f u l l - s c a l e i n t e g r a t e d f a c i l i t y having a configuration s i m i l a r t o t h a t sf t h e nolten-salt t e s t reactor. However, i t w i l l o p e r a t e ~ S S thermally and only slow temperature t r a n s i e n t s will b e p o s s i b l e .

18.13.2

Schedule

A s i n d i c a t e d i n Table 10.l3.2, c ~ n c e p t d~els i g n of the Components Test F a c i l i t y b e g i n s i n PP 1978 and csnstruction will b e complete by FY 1982.

10 1% 3 D

Funding

Operating fund requirements f o r this task group a r e shown i n Table 10.13.3.1. A u t h ~ r i z a t i o nof funds t o cover t h e d e s i g n and c ~ n s t r u c t f ~ n sf t h e CTP w i l l b e r e q u i r e d i n e a r l y E T 1980. A p r e l i m i n a r y estimate af the c o s t of t h e b a s i c f a c i l i t y i n which test system would b e hssated is $10 m i l l i o n ; however, no d e t a i l e d d e s i g n and c o s t a n a l y s i s has been c a r r i e d o u t f o r o b t a i n i n g t h i s estimate. C a p i t a l equipment fund requirements for thrfs t a s k group are shown i n Table 10.13.3 - 2

10.13.4

Facilities

The C~mponentsT e s t F a c i l i t y w i l l c ~ n s i s tof a l o c a t i o n t h a t i s s u f f i c i e n t l y large t0 house the Steant GWierator Model T e s t Stand afld t h e P r o t o t y p e Pump Teat Stand, as w e l l as i n d i v i d u a l t e s t f a c i l i t i e s f o r l a r g e - s c a l e components such a s valves, c o n t r o l r o d s , and c o r e components. A l a r g e e l e c t r i c a l power supply w i l l b e i n s t a l l e d t o o p e r a t e pumps and o t h e r equipment and t o p r o v i d e e l e c t r i c a l h e a t i n g f o r s a l t - c o n t a i n i n g l i n e s and components. A v e n t i l a t i o n system w i l l b e provided w i t h adequate f i l t r a t i o n and a i r cleanup t o a s s u r e containment of hazardous materials i n c l u d i n g b e r y l l i u m - c o n t a i n i n g compounds and BF3. Cooling w a t e r and o t h e r utilities will b e i n s t a l l e d , as w e l l as general-purpose modular instrumentation. Computer systems f o r r e c o r d i n g and a n a l y z i n g d a t a w i l l ~ S C bI e i n c l u d e d . An e a r l y a c t i v i t y a s s o c i a t e d w i t h t h e conc e p t u a l d e s i g n of t h i s f a c i l i t y will b e t o survey p o t e n t i a l space f o r t h e f a c i l i t y , and t o complete the conceptual d e s i g n of a b u i l d i n g if s u i t a b l e s p a c e i s not a v a i l a b l e .

10.13.5

Task 9 . l B . l

Conceptual d e s i g n of t h e f a c i l i t y

Xn this t a s k c o m p i l a t i o n s w i l l b e made s f all components and s y s t e m t o b e t e s t e d , t h e t y p e of t e s t t o b e made, t h e u t i l i t i e s , s a l t r e q u i r e m e n t s , and o t h e r p e r t i n e n t i p z f o r m t i o n i n order t o complete a conceptual d e s i g n . '%hisf a c i l i t y w i l l b e used t o t e s t l a r g e - s c a l e steam g e n e ~ ~ t ~ pumps, rs, v a l v e s , h e a t exchangers, and o t h e r components. Adequate e l e c t r i c a l supply

Table

18.13.2.

Schedule

fsr

wcxk

Task

Group

9 .lQ

- Components

Test

Facility

Group

9.10

9.1Q.l

CTF csnceptual

9.18.2

CTP final

9.18.3

CTF construction

Table

design

10.13.3.1.

Operating

fund

requirements

Cdampsnents (costs

9.10.1

Canceptual

9.lQ.3

G%P construction

120

design

Facility

BON3

dollass)

work

Task

9 * 10.4 CTF operation Total operating funds Task Group 9.%0

for

Test

15Q

BOO

245

725 I__--

1610

2300

200

345

725

1610

2300

for 12Q --

Table

9.10.4

Total

10.13.3.2.

Capital Camponents

Miscellaneous instrumentation capital

equipment

equipment Test Facility

equipment

funds

fund requirements (costs in 1000

far Task dollars)

Grsup

Fiscal

year

9.10

1982

1983

1984

19 85

75 -c_ 75

411

579 _____ 579

1023

and

for

Task

Group

9.10

411

1023

1986

w i l l b e provided f o r o p e r a t i n g l a r g e loops. F i l t e r e d exhaust systems, overhead c r a n e s , and modular i n s t r u m e n t a t i o n and h e a t e r c o n t r o l s will b e i n s t a l l e d t o accommodate v a r i o u s t y p e s of developmen%.

T h i s t a s k c o n s i s t s of (1) e s t a b l i s h i n g c r i t e r i a f o r t h e CTF, (2) p r e p a r i n g a s a f e t y a n a l y s i s and environmental s t a t e m e n t , ( 3 ) developing a p r e l i m i n a r y l a y o u t and d e s i g n f o r t h e C W , i n c l u d i n g i n s t r u m e n t a t i o n and c o n t r o l s , ( 4 ) p r e p a r i n g a c o s t estimate f o r t h e p r o j e c t , and (5) p ~ @ p a r i n g and s u b m i t t i n g a long form c o n s t r u c t i o n p r o j e c t d a t a s h e e t f o r FY 1980 a u t h o r i z a t i o n .

10.13.6

Task 9.10.2

T i t l e I and T i t l e I1 d e s i g n of t h e f a c i l i t y

T i t l e I d e s i @ of t h e f a c i l i t y w i l l b e g i n a f t e r p r o j e c t a u t h o r i z a t i o n i n Operati n g fund requirements d u r i n g d e s i g n of t h e f a c i l i t y cover p e r s o n n e l i n c l u d i n g t h e program and p r o j e c t e n g i n e e r s , d e s i g n work n o t covered by c a p i t a l p r o j e c t funds, e s t i m a t i n g , and l i a i s o n between program and p r o j e c t activities.

FY 31988 and T i t l e I1 d e s i g n w i l l b e completed d u r i n g e a r l y 1981.

10 .P3.7

Task 9 60.3

C o n s t r u c t i o n of t h e f a c i l i t y

C o n s t r u c t i o n w i l l begin i n mid PY 1980 and w i l l c o n t i n u e u n t i l l a t e FY 1982. Operating funds a r e r e q u i r e d f o r s u p p o r t of t h e program and p r o j e c t engineers e

10.l3.8

Task 9.18.4

Operation of t h e f a c i l i t y

Operation of t h e f a c i l i t y w i l l b e g i n i n l a t e PY 1982 and will c o n t i n u e f o r an i n d e f i n i t e p e r i o d . The i n i t i a l a c t i v i t y w i l l be a s s o c i a t e d with the requirements f o r t h e MSTR, however, t h e l a t e r work w i l l b e i n support of subsequent reactor component development requirements. REFERENCES PO8 SECTION 1 0 .... . ... ..j

ORNt-TM-3030, E R E Systems and Compoxen.ks Perfommce by MoltenS a l t Reactor Experiment S t a f f , e d i t e d and compiled by Et. H. Guymon, June 1973.

...

... :&

C. H. Gabbard, Devebpinent of a Ventug-L?pe

Bubble Genepator fop Use i n t h e MoZten-SaZt Reactor Xenon ??ernoval $,ustern, OIZNL-TM-4122, December 1972.

.... ;::= ...

Development of a:? Axial-Plow Centrifugal Gas Bubble Separator for Use ix MSR Xenon Removal Systzms , OR?&-CF-72-12-42, C . H. Gabbard,

December 1972.

IQ-86 4.

7. 8. 9.

11.

L3. 14

16.

17. 18. 19.

16-81 22.

MSR Ptaogrmn Semiann. Frogr. Be@. Aug. 32, 1971, 8 m L - 4 7 2 8 , p a 1 5 2 .

23.

c. E. ~ e t t i set a%. , Design Study of R: Heat Zxchanger System ~ C W One MSBR Concept , ORNL-TM-I545 (September 1967) e

a?..,

6 . E. B e t t i s et a l . Computer Progrms f o r -the Design of MSBR Heat Exchangers, OWL-'PPI-2815 (1990).

W. C. B r i a n t , A. M. Weinberg, E. S. B e t t i s , W. K. Ergen et a%., rirucZ. Sci. Eng. 2 : 797. R . C . Robertson, !4SRE Design. and Opwations Report, Part I, t i o n of R e a c t s ~Design, ORNL-TM[-728 ( J a n u a r y 1965)

Descpip-

J . P. Sanders, A -?euiai of Possible Cnoices for Seeordog Coolant for Molten-SaZt R e a c t o m , i n t e r n a l memorandum, August 6, 1971. 2%.

A. N. S m i t h , Experience w i t h FZuorsborate CircuZation i n an !&RE (September 1972)

S c a k Loop, QRNL-TM-3344 29.

3. W. Moger, MSR F ~ o g r mSehann. Frogr. Rept. Aug. 32, 1970, OW-4622.

W. R. Huntley, S R Program Sen6awt. B o g r . Rept. Aug. 31, 1971,

ON-4728

Concepttca2 Design Stud? of a Single-Fluid No lten-Salt Breeder Reactor, O%ghw,-4541 (1971) e

32.

Adam, W. E . ,

B K O W ~ ~ I W. I ~ , E. Jr., and Aclcley, R. D.,

Containment

of Radioactive F i s s i o n Gases b y Dynamic Adsorption," Ind2striaZ and

Engineerixg Chemistq 5 1 : 1467-P470 (December 1959) .

( E J N 10578)

33.

PSBB f o r an MSR Coolant-Salt Technology Facility (CSTP) ORNL-GF-72-6-17 (6-30-72).

34.

R. B. Korsmeyers "The E f f e c t of Hydrogen Back-Biffusion on t h e Transport of Tritium i n an MSBR," OEQNL-CF-Sl-5-lO (May 1971)

35.

8. B . Briggs, "The E f f e c t s f Q x i d e Coatings and Molten Salt F i b e r s on the Permeation of Hydrogen Through Metal Walls," ORNL-CP-73-1-26 (January 1973 )

36.

H. D. McLain, ''The CSTP Deuterium Experiment f o r t h e MSR Program," MSB-93-16 (January 1973).

37. MSR Semi-AruzuaZ @ogre

Report. P/E 2 / 8 / 6 9 > ORE%L-4396 (1969)

k....

1%1 INTRODUCTION a

The maintenance of a l l r e a c t o r s r e q u i r e s t h e perfommce of v a r i o u s mechanical o p e r a t i o n s on equipment which, because s f r a d i o a c t i v e cont a m i n a t i o n and a c t i v a t i o n , i s n o t d i r e c t l y a c c e s s i b l e t u maintenance p e r s o n n e l . Depending upon t h e l e v e l of a c t i v i t y , t h e s i z e of equipment, and t h e d e s i g n p r o v i s i o n s f o r maintenance, anything from simple l o c a l s h i e l d i n g t o f u % l y remote manipulation may be r e q u i r e d . The time req u i r e d t o do maintenance and t h e c o s t of t h e maintenance p r o v i s i o n s i n c r e a s e w i t h t h e degree of r e ~ a ~ t e n e sr es q u i r e d .

The c i r c u l a t i n g - f u e l r e a c t o r has f i s s i o n p r o d u c t s and i n t e n s e r a d i a t i o n t o contend with n o t only i n t h e r e a c t o r vessel b u t a l s o i n a l l of t h e primary c i r c u i t through which t h e f u e l s a l t c i r c u l a t e s , t h e off-gas system, and i n t h e f u e l p r o c e s s i n g p l a n t . Thus t h e c i r c u l a t i n g - f u e l r e a c t o r r e q u f r e s r a d i o a c t i v e maintenance of a g r e a t e r scope than does a f i x e d - f u e l r e a c t o r . On the o t h e r hand, t h e r e f u e l i n g o p e r a t i o n is s i m p l e r , t h e r a d i o a c t i v i t y is r e t a i n e d o n - s i t e w i t h i n one containment, and t h e n e c e s s i t y of a s e p a r a t e maintenance o r g a n i z a t i o n and equipment f o r a f u e l r e p r o c e s s i n g p l a n t a t a n o t h e r s i t e i s avoided. Although maintenance d e s i g n e f f o r t s cannot a f f e c t t h e s i z e and a c t i v i t y l e v e l of t h e components i n a r e a c t o r , much can be done in t h e d e s i g n s t a g e s of a p l a n t t o i n f l u e n c e s t r o n g l y t h e degree of a c c e s s i b i l i t y and t h e complexity of the maintenance o p e r a t i o n . The maintenance concept f o r an MSBR i s c h a r a c t e r i z e d by t h e f o l l o w i n g g e n e r a l p r f ~ c i p f e s :

Each system i s composed of manageable u n i t s j o i n e d by s u i t a b l e d i s c o n n e c t s and b i n e s which can b e c u t and rewelded remotely.

Each u n i t is a c c e s s i b l e and r e p l a c e a b l e from d i r e c t l y above through removable sRieHding.

F a i l e d u n i t s are removed and r e p l a c e d .

Much of t h e maintenance e x p e r i e n c e on which t h i s concept rests r e s u l t e d from appljbcation of t h i s approach to t h e MSm. h % g ~t h e simp%es.t:s f i n s p e c t i o n s and r e p a i r s could be done on f a i l e d equipment f o t~h e MSRE; however, i n an MSBR economic c o n s i d e r a t i o n s w i l l d i c t a t e c o n s i d e r a t i o n 0 f more e x t e n s i v e r e p a i r c a p a b i l i t i e s e

11 1.P e

Ob j e c t i v e

The o b j e c t i v e s of work i n t h i s a c t i v i t y are t o develop t h e technology r e q u i r e d f o r m a i n t a i n i n g t h o s e p o r t i o n s of an MSBR which r e q u i r e remote 8% sewirewaste maintenance t e c h n i q u e s , and t o o b t a i n improved estimates of t h e impacts of maintenance on t h e economic and n u c l e a r perfomanse of MSBRs. The work i n t h i s a c t i v i t y w i l l i n t e r f a c e s t r o n g l y w i t h t h a t i n Reactor Design and Analysis ( S e c t i o n 8 ) .

11-1

11.1.2 Scope The SCope O f W O P k t h i s a c t i v i t y CQnSiSts O f t h e COnsideratiOn O f remote maintenance requirements d u r i n g t h e p r e l i m i n a r y and c o n c e p t u a l d e s i g n of m o l t e n - s a l t r e a c t o ~ s ( i n c l u d i n g t h e lOOO-~T(e) r e f e r e n c e d e s i g n KSBR, a demonstration r e a c t o r , and a test r e a c t o r ) , t h e development of t h e remote maintenance technology r e q u i r e d by t h e s e r e a c t o r s and che development of equipment and techniques f o r remote i n s p e c t i o n of w e l d s . c o n s i d e r a t i o n of i n - s e r v i c e i n s p e c t i o n o f a l l t y p e s a l s o f a l l s w$tbin t h e scope of t h i s a c t i v i t y .

$1.2

P W Q G M BUDGET' AND SCHEDULE

A summary schedule f o r work on development of MSBR remote maintenance technology i s s k o m i n Table l1.2.l.B. The key m i l e s t o n e s f o r work on MSBR maintenance a r e given i n Table 1 1 . 2 . 1 . 2 and occur a t t h e times s h o w i n Table Pl.2.1.1.

Operating fund requirements f o r work MSBR maintenance a r e summarized i n Table lf.2.2.1, and c a p i t a l equipment fund requirements are summarized in T a b l e 1 1 . 2 . 2 . 2 .

Pl.3.l

Technological background

During t h e past: 1% t o 28 y e a r s , t h e n u c l e a r i n d u s t r y has a c q u i r e d a g r e a t deal of e x p e r i e n c e i n t h e maintenance of r a d i o a c t i v e systems. Some has come from having t o make r e p a i r s under very d i f f i c u l t c o n d i t i o n s . A few suck j o b s have n e c e s s i t a t e d u n d e s i r a b l e exposure t o p e r s o n n e l ; o t h e r s have r e q u i r e d ingenious d e v i c e s and v e r y lolag t i m e s t o accomplish. Although t h e s e f e a t s have been i n s t r u c t i v e , they are n o t models t o f o l l o w . The g o a l i n d e s i g n i n g a r e a c t o r i s n o t only t o make maintenance p ~ s s i b l e , b u t t o make i t as s u r e , as s a f e , and as economical as i t can b e . The e x p e r i e n c e that p o i n t s t h e way t o t h i s o b j e c t i v e i s t h a t a c q u i r e d d t h t h o s e p l a n t s i n which maintenance w a s planned, provided f o r , and une v e n t f u i i y c a r r i e d O U ~& s p i t e h i g h levels of r a d i o a c t i v i t y here has be@n t?XperienCe sf t h i s SQr?. hl VarioUS USme i n S t % l l a t i O K i S , b o t h I d t h r e a c t o r s and with chemical p r o c e s s i n g p l a n t s , t h a t p r o v i d e s a broad technslogisaH b a s i s f o r developing t h e maintenance system f o r an MSBR,

,. .. ......... c<.c

k....

,...*

11-3 ..&

...., m

at o m , f o u r c i r c u l a t i n g - f u e l r e a c t o r s ( m-1, m--2,aRd m E ) have been ~ p e r a t e d ,as w e l l as p r o c e s s i n g f a c i l i t i e s of v a r i o u s k i n d s . A l t h ~ u g ht h e l e v e l of r a d i o a c t i v i t y v a r i e d , they a l l contained complex systems for c i r c u l a t i n g , p r o c e s s i n g , and s t o r i n g r a d i o a c t i v e materials whose a c t i v i t y levels denied d i r e c t a c c e s s . The need f o r maintenance w a s recognized i n advance, and maintenance p r o v i s i o ~ a sw e r e made i n t h e i r design. Development programs a l s o i n c l u d e d maintenance p l a n n i n g and p r a c t i c e . The p r e p a r a t i o n s for maintenance of t h e MSRE, the orga~ i z a t i ~ nand , t h e eonduct sf t h e maintenance o p e r a t i o n s a c t u a l l y p@lrfoHngd 01% t h e ?%ma r e d e s c r i b e d in ref@K@RCe4 and t h e MSR Prografn semiannual p r o g r e s s r e p o r t s from 1967 through 1371. 311.3.1.1

P r e p a r a t i o n s for MSRE maintenance

P r e p a r a t i o n s f o r m a i n t a i n i n g t h e MSRE began w i t h t h e irnvolvewent of maintenance s p e c i a l i s t s in the d e s i g n , and continued through t h e cons t r u c t i o n and s t a r t u p phasesQ4 The f i r s t scheme v i s u a l i z e d f o r the PISRE f e a t u r e d a bridge-mounted m a n i p u l a t o r , o p e r a t e d i n an enclosed s p a c e above t h e r e a c t o r c e l l and c o n t r o l l e d remotely w i t h the a i d of (A maintenance development f a c i l i t y i n c l u d i n g a m a n i p u l a t o r , television. viewing d e v i c e s , and equipment mockups had been used a t O$wE to show t h e f e a s i b i l i t y of t h i s approach.) Smaller j o b s i n t h e MSRF; w e r e t o b e done by t h e semi-remote t e c h n i q u e proved i~ the €ERE-2, using s i m p l e , long-handled t o o l s manipulated by hand through small p e n e t r a t i o n s i n a port&ble Shield Set Up Over ilR Opelling i n t h e C e l l ' s SoIlClrete roof. Design and p l a n n i n g soon showed t h a t the maintenance work a n t i c i p a t e d i n t h e MSRE could b e done in t h i s s i m p l e r way, and t h e manipulator i d e a w a s set a s i d e .

The MSRE p o r t a b l e maintenance s h i e l d was a s e t of t r a c k s and several &2--in.-thick s t e e l s l a b s , w i t h h o l e s f o r t o o l s and viewing d e v i c e s , t h a t r o l l e d on t h e t r a c k s . I n s e r t s f o r t h e h o l e s included s h i e l d i n g windows,

.:a

l i g h t s , and s p l i t bushings ta f i t a r o ~ n dt o o l s h a f t s . When very f r e e t ~ o mvement l was required, bags of steel shot around the shaft blocked the r a d i a t i o n . Lifting d e v i c e s p e r m i t t e d t h e remotely c ~ n t ~ l l e d b u i l d i n g crane t o remove s h i e l d b l o c k s o r major equipment i t e m s . Each removable i t e m had a b a i l a t t h e center of g r a v i t y O K o t h e r p r o v i s i o n s t o s i m p l i f y l i f t i n g . Guides were provided where n e c e s s a r y t o steer replaement p a r t s i n t o glace. To ensure p r o p e r f i t , j i g s ~ 7 e r eb u i l t f o r a l l of t h e major r e p l a c e a b l e c o m p ~ ~ e n t s ."'he 5-in. s a l t l i n e s w e r e previded w i t h f l a n g e s t h a t used f r o z e n s a l t as a b a r r i e r t o keep molten s a l t away from t h e ring gasket. ~ a c h i n e swere d e v e h p e d (and fixtures i n s t a l l e d i n t h e c e l l f o r them) t h a t COUP^ eut the 1 - l / 2 - i n e l i n e s t o t h e d r a i n t a n k s , p r e p a r e the e n d s , b r i n g o l d and new p i e c e s t o g e t h e r , and join them by brazing. The o n l y t o o l s r e q u i r e d f o r mst o p e r a t i o n s were s i m p l e , long-handled hooks, wrenches, and clamps c h a r a c t e r f a e d by t h e i r r e l i a b i l i t y r a t h e r than by t h e i r v e r s a t i l i t y .

During the i n s t a 1 l a t i o w sf t h e reactor equipment and t h e prepcawer testing, many of t h e maintenance p r o v i s i o n s were t e s t e d . A I 1 sf t h e primary loop w a s assembled ow a l a r g e jig b e f o r e going i n t o t h e cell and optical

11-5

Key mihestones for development of MSBR remote

Table 11.2.1.2.

maintenance technology Miles tone a

Description Go~lnplete survey of MSBR maintenance requirements

Complete determtnation of maintenance requirements f o r

MSBR components. Complete determination of maintenance requirements f o r demonstration reactor. Determine maintenance-related design restrictions and complete evaluation of impacts on MSBR performance. Complete deterdnation of test reactor maintenance requirements and tabulate o v e r a l l maintenance reqUiPement§ f o r MSR§.

.... ..:.=,

& :&

Complete survey and development plans for r e ~ o t epipe cutting, remote seal weld cutting and welding, remote pipe spreading and alignment t e c h n o l ~ ~and , remote pipe welding techniques.

Complete survey and development plans for improved viewing devices *

Complete maintenance development related to design of test reactor a

,:..... :.=

...., 2..

... ..;<.. .A

.:;,>... .-.-

.... .-=.>

.. i i ..,

Complete survey f o r adaptation o f customary weld inspection techniques t o KSBR maintenance.

Determine potential for application of advanced weld inspection methods to MSBR maintenance and complete development plans.

10.2

Devehpment technology

a-f remate

maintenance 80

336

650

497

448

436

385

Table

11.2.2.2.

Capital

equipment fund requirements remote maintenance technology (costs in 1000 dollars)

for

development

Fiscal

10.2

Development maintenance

equipment

for

remote

XII.3

Development fsr psst-weld

equipment inspection

and

techniques

for

maintenance

Total capital technolagy

equipment

funds

year

MSBR

11-8

t o o l i n g w a s used ' t o l o c a t e r e f e r e n c e p o i n t s i n t h e c e l l p r e c i s e l y . Maintenance items t h a t were t e s t e d i n c l u d e d t h e c r a n e , l i f t i n g and viewing d e v i c e s , and t h e v a r i ~ u st y p e s of d i s c o n n e c t s . F r e e z e f l a n g e s were opened and c l o s e d ; a c e l l - s p a c e c o o l e r , t h e c o n t r o l r o d s , r o d d r i v e s and a c o r e - s ~ ~ ~ ~apr b r aey w e r e removed and r e p l a c e d ; t h e primary h e a t exchanger and f u e l pump bowl w e r e i n s t a l l e d u s i n g i n p a r t t h e remote maintenance p r o v i s i o n s A f t e r t h e n u c l e a r s t a r t u p experiments t h e f u e l pump r o t a r y element w a s removed, i n s p e c t e d and r e i n s t a l l e d . During t h i s t i m e p e r s o n n e l were t r a i n e d and procedures w e r e p e r f e c t e d .

11.3.1.2

E x t e n t s f MSW e x p e r i e n c e

The semi-remote j o b s t h a t were accomplished i n t h e r e a c t o r and d r a i n tank c e l l s d u r i n g t h e 4-1/2 y e a r s of n u c l e a r o p e r a t i o n are summarized i n Table 11.3.l.2. With t h e e x c e p t i o n of t h o s e c a r r i e d o u t i n 1965 ( b e f o r e highpower o p e r a t i o n ) $ all of t h e j o b s involved components t h a t were l o c a t e d i n r a d i a t i o n f i e l d s of s e v e r a l thousand W/kr. The r a d i o a c t i v i t y of t h e i t e m s t h a t were removed v a r i e d w i d e l y ; some, such as t h e specimens that were removed from t h e c o r e 5 t o 7 days a f t e r shutdown, r e a d several hundred W/hr at s e v e r a l f e e t . A 1 1 of the j o b s involved use of the r e ~ i ~ o t e maintenance c o n t r o l room, a t l e a s t f o r s e t t i n g up and removing the maintenance s h i e l d . The c e l l - t o p membrane w a s c u t , welded, and i n s p e c t e d each t i m e maintenance w a s done.

h a d d i t i o n to t h e maintenance in the r e a c t o r and d r a i n - t a n k c e l l s , t h e r e were s e v e r a l j o b s i n v o l v i n g h i g h l y radioactive components i n o t h e r p a r t s of t h e b u i l d i n g . Valves and f i l t e r s i n t h e off-gas system were removed and r e p l a c e d , and h e a t e r s w e r e i n s t a l l e d on t h e i n l e t s of t h e off-gas c h a r c o a l beds. The fuel-sampler d r i v e mechanism had t o be r e p a i r e d on s e v e r a l o c c a s i o n s , which r e q u i r e d t h a t a temporary wood-andp l a s t i c containment e n c l o s u r e be set up i n s i d e t h e reactor b u i l d i n g . The p o s t - o p e r a t i o n a m i n a t i o n s c a r r i e d o u t between November 1998 and February 1 9 7 1 involved viewing i n t h e c o r e and i n t h e f u e l pur@, c u t t i n g out s e v e r a l p a r t s of the fuel s a l t system, and plugging some The general technique w a s t h e same as wx used in maintaining the r e a c t o r : long-handled t o o l s through t h e maintenance s h i e l d . Some of t h e t o o l s were q u i t e d i f f e r e n t , however, t o handle t h e s p e c i a l t a s k s .

The c o n t r o l r o d s and d r i v e s were removed, t h e 10-in. core-access p l u g with t h e rod thimbles w a s t a k e n o u t , anad a s e c t i o n of rod thimble w a s c u t o f f w i t h a granding wheel. A g r i n d i n g wheel, ntounted on a s p e c i a l t o o l , w a s a l s o used t o cut through t h e pump t a n k around t h e sampler cage so t h a t i t c ~ ~ be l dremoved. An 11-in. s e c t i o n of the h e a t exchanger s h e l l was c u t o u t w i t h a plasma t o r c h , then sections of six t u b e s were c u t w i t h an a b r a s i v e cutoff t o o l and removed for inspection. Examination showed that, as s u s p e c t e d , a small m o u n t of s a l t ( ~ 2in-4) had l e a k e d n e a r a f r e e z e v a l v e i n a d r a i n l i n e . The f r e e z e v a l v e and a d j a c e n t p i p i n g was c u t o u t and removed. The h o l e s i n t h e pump tank and t h e heat exchanger s h e l l were p a t c h e d , t h e l a t t e r by welding, and p l u g s were i n s t a l l e d i n t h e severed ends of the d r a i n lines.

....

,&2.:<

11-9 Table 16.3.1.2.

Semi-remote work i n MSRE r e a c t o r and d r a i n c e l l s a f t e r beginning of n u c l e a r operation'

Remove , i n s p e c t , r e p l a c e f uel-pump rotary element ( 3 /65) I n s p e c t c o r e and r e a c t o r vessel,

K ~ B H ) V broken ~

graphite (9165)

Remove a n d / o r r e p l a c e c o r e sample a r r a y ( 9 / 6 5 , 9 / 6 6 , 5 / 6 7 , 4 / 6 8 , 6/69, 12/69) Pimove flow r e s t r i c t o r in e q u a l i z e r line i n r e a c t o r c e l l ( 2 f 6 6 )

I n s t a l l thermocouple on off-gas l i n e i n r e a c t o r c e l l 63/66] I n s t a l l and remove temporary h e a t e r on gas l i n e s at FP (8-9/66, 11/6 6) Rod o u t off-gas l i ~ a e t f u e l pump e x i t ( P P f 6 6 , 4 / 6 8 , 12/68)

Replace f u e l pump off-gas jumper l i n e 69/66, 1 2 / 6 6 , 4 / 6 8 ) Replace overflow tank v e ~ tl i n e (6169) I n s t a l l permanent h e a t e r on off-gas l i n e a t f u e l pump (6/69)

~ e m v eand r e p l a c e c o n t r o l - r o d d r i v e (9166% 5/67, 6/69)

4 8 6 8 , 1/69,

Replace c o n t r o l r o d ( 9 1 6 6 , 6/69) Remove, i n s p e c t , r e i n s t a l l c o n t r o l rod (1169)

Remove, r e p a i r , r e h s t a l l h e a t e r s on primary EB ( 3 - 4 f 6 8 ) Replace r e a c t o r c e l l space c o o l e r motor ( 6 / 6 5 ) Remove, repair leaks, replace r e a c t o r c e l l s p a c e c o o l e r (8-9/66) Replace r e a c t o r c e l l s p a c e c o o l e r ( 5 1 6 7 )

Replace a i r - l i n e d i s c o n n e c t s i n r e a c t o r c e l l and d r a i n c e l l (1/67, 7/69) Kemove, repair, r e p l a c e a i r c o n t r o l valve i n r e a c t o r cell (B2/66) Measure g a m s p e c t r a from components i n r e a c t o r c e l l (5/6%, 4 / 6 8 , 6 / 6 9 , 11/69)

~isuably scan r e a c t o r c e l l ( 5 - 6 / 6 7 , 2/68) Visually scan d r a i n cell ( 6 / 6 7 )

Install and remove sampler-enricher on d r a i n t a n k (8-9/68) %sw-power 1966.

experiments began in June 1965; high-power

o p e r a t i o n in A p r i l

li-10

ll.3.E.3

S i g n i f i c a n ~ eof MSRE maintenance e x p e r i e n c e

Although t h e m j o r components of t h e fuel system, whose ~ e p l a c e ~would ~~i~~t have been more complicated t h a n any job t h a t w a s done, r e q u i r e d no maintenance, t h e MSW e x p e r i e n c e was s u f f i c i e n t t o thoroughly test t h e g e n e r a l maintenance s t r a t e g y and many of t h e s p e c i f i c d e s i g n f e a t u r e s .

151"

maintenance system w a s r e l i a b l e : no j o b a r o s e t h a t could n o t b e done. An important f a c t o r w a s t h e f l e x i b i l i t y of t h e maintenance system which allowed o b s t a c l e s t o b e circumvented and unforeseen j o b s (such as t h o s e i n t h e off-gas system) t o b e accomplished.

The %WE

The experience with the PISRE emphasized t h a t t h e payoff f o r p r e p a r a t i o n i s tremendous i n t h e ease of r a d i o a c t i v e maintenance. Jobs suck as r e p l a c i n g t h e C O K ~specimens went v e r y q u i c k l y compared t o o t h e r s t h a t w e r e b a s i c a l l y less d i f f l c u l t , b u t f o r which no s p e c i a l p r o v i s i o n s had been made. E s p e c i a l l y v a l u a b l e i n f o r m a t i o n on f i s s i o n - p r o d u c t contamination came experfence. Noble gases behaved p r e d i c t a b l y and could be purged b e f o r e s y s t e m were opened. S a l t - s e e k i n g f i s s i o n p r o d u c t s w e r e no problem - t h e s a l e d r a i ~ e dc l e a n l y and any t h a t was t r a p p e d f r o z e and r e t a i n e d t h e f i s s i o n p r o d u c t s . There w a s no c o r r o s i o n film o r scale t o f l a k e o f f and become a i r b o r n e . A t l e a s t p a r t of t h e n o b l e metals t h a t d e p o s i t e d on s u r f a c e s i n t h e off-gas system w e r e f a i r l y e a s i l y t r a n s f e r r a b l e , b u t p a r t i c u l a t e contamination w a s g e n e r a l l y confifleel t o t h e t o o l s , which w e r e swabbed and bagged as t h e y w e r e p u l l e d from the shield. Iodine t h a t was produced by t h e decay 0 % t e l l u r i u m on s u r f a c e s soon appeared i n the a i r i n t h e reactor c e l l . V e n t i l a t i o n air from t h e rea c t o r b u i l d i n g and from the containment c e l l s w a s passed through p a r t i c d a t e filters and up a s t a c k . The g r e a t e s t amount of a c t i v i t y d i s c h a r g e d as less than 8 . 2 61 (mostly i o d i n e ) and o c c u r r e d d u r i n g wark Although r a d i a t i o n l e v e l s i n the r e a c t o r c e l l w e r e t y p i c a l l y on the o r d e r of s e v e r a l thousand ~ / h w r h i l e maintenance work w a s going on, t h e g e n e r a l background to which workers were exposed w h i l e m a n i p u l a t i n g tools w a s only about 0.01 W h r . Procedures w e r e planned t o minimize p e r s o n n e l exposure i n l o c a l l y h i g h e r radiation f i e l d s and the work w a s never s e r i o u s P y inconvenienced by havimg to r o t a t e workers. No w i n t e l s Z X l C e Worker gVeP reSeiVed 1910Pe than t h e n O ? 3 € d limit of 3 %em hl ally

quarter .... 11.3.2

KSBR maintenance requirements

In d e s i g n i n g and p l a n n i n g f a r t h e maintenance of the MSBR, the e x p e r i ence w i t h t h e FISH3 and other r a d i o a c t i v e systems h a s been e v a l u a t e d and adapted t o the e x t e n t possible. The maintenance system f o r t h e r e f e r e n c e MSBR is d i s c u s s e d i n some Betail i n ORNL-L~NI.~

ll-11

P1.3.2.P

Classes of maintenance

NSBK maintenance requirements f i t i n t o t h e f o l l o w i n g f o u r g e n e r a l classes. Class I - Pemanent Equipment. This c a t e g o r y c o ~ ~ t a ai l~l ~i tse m s which can r e a s o n a b l y be expected t o r e q u i r e maintenance d u r i n g t h e d e s i g n l i f e t i m e sf t h e p l a n t . Examples are the r e a c t o r vessel, t h e p m p v e s s e k s , p r i m a r y h e a t exchanger s h e l l s , t h e f u e l - s a l t d r a i n tanks thermal s h i e l d i n g thermal i n s u l a t i o n t h e connecting p r o c e s s p i p i n g , e t c . NQ s p e c i a l p r o v i s i o n s are i n c l u d e d f o r w i n t e n a c e of t h e s e items. Emergency maintenance t o some e x t e n t is p o s s i b l e , however, because of t h e access t h a t i s provided p r i m a r i l y for in-service inspection.

Class I1 - Equipment Allowing Direct Maintenance. This group i n c l u d e s t h e i t e m s which can normally b e approached f o r d i r e c t maintenance w i t h i n a r e a s o n a b l e p e r i o d ~f time ( t y p i c a l l y a f t e r the secondary s a l t h a s been d r a i n e d and f l u s h e d and t h e remaining a c t i v i t i e s allowed t o decay f o r about t e n d a y s ) . The s t e a m genera t o r s , r e h e a t e r s , c o o l a n t - s a l t pumps, and the equipment i n t h e h e a t r e j e c t i o n c e l l fall i n t o t h i s class. In the u n l i k e l y e v e n t t h a t one of t h e s e ~ O T I ~ Q ~ ~dIi Id ~ become S h i g h l y contaminated w i t h fission p r o d u c t s , i t s r e ~ l ~ v would al be t r e a t e d as a Class IIT or IV i t e m , d i s c u s s e d below. Once t h e s o u r c e s of a c t i v i t y w e r e removed from t h e c e l l , cleanup and component replacement could proceed i n the n o m a l f a s h i o n u s i n g d i r e c t maintenance. Much of

Ils, such as pumps, blowers, valves, p r o c e s s i n g vessels, f i l t e r s , e t c . , will become r a d i o a c t i v e . In g e n e r a l , the s i z e s of t h e s e i t e m are comp a r a b l e t o the MS equipment. MSBR r a d i a t i o n levels may b e a .... .m

.... ::x,a

f a c t o r s f l o h i g h e r than i n t h e PISRE, however. n e maintenance tools for t h i s class of equipment c o u l d be similar t o t h o s e f o r t h e MSW, b u t t h e s h i e l d i n g and c ~ n t a i n m e ~provisiorss ~t would have t o b e %itore e f f e c t i v e because of t h e more i n t e n s e s o u r c e s sf radiation.

Class I V - Large Equipment R e q u i r i n g Remote Maintenance. This group i n c l u d e s item which are c l e a r l y beyond p r e s e n t e x p e r i e n c e because of a combination of s i z e , r a d i a t i o n level, a f t e r h e a t removal, and d i s p o s a l c o n s i d e r a t i o n s . Examples are t h e pump r o t a r y element, t h e primary hea% exchanger t u b e b u n d l e , and the core g r a p h i t e a

The r e a c t o r primary system, because of t h e Barge s i z e of the h i g h l y contaminated equipment, p r e s e n t s t h e g r e a t e s t problems i n c o n t a i n i n g the r a d i o a c t i v i t y and d e a l i n g w i t h afterheat and i s t h e r e f o r e used as the b a s i s f o r the d i s c u s s i o n which follows.

11-62

11.3.2.2

Containment c o n s i d e r a t i o n s

Although t h e f u e l s a l t and h i g h l y r a d i o a c t i v e gases w i l l b e removed from any s y s t e m b e f o r e i t i s opened f o p maintenance, t h e r e a c t o r primary system w i l l s t i l l c o n t a i n l a r g e mounts of r a d t o a e t i v i t y , some of which w i l l be transferable. The MSBR b u i l d i n g and c e l l s and t h e maintenance equipment and proeedu-res musts t h e r e f o r e , b e designed so as t o l i m i t the spread of r a d i o a c t i v e material w i t h i n t h e r e a c t o r b u i l d i n g and t o p r e v e n t more than t r i v i a l mounts from b e i n g r e l e a s e d o u t s i d e t h e b u i l d i n g during maintenance.

The f i s s i o n - p r o d u c t decay h e a t i n g and t h e amounts of s h o r t - l i v e d a c t i v i t y that must b e d e a l t with decrease rapidly d u r i n g t h e f i r s t few days a f t e r c e s s a t i o n of power o p e r a t i o n . For t h i s r e a s o n , i t i s u n l i k e l y t h a t t h e primary system w i l l b e opened sooner t h a n t e n days a f t e r full-power o p e r a t i o n is s t o p p e d .

Ten days a f t e r shutdown from s u s t a i n e d o p e r a t i o n a t 2250 MJ(t9, t h e noble-metal f i s s i o n p r o d u c t s on s u r f a c e s may total about 2.2 x I O 8 c u r i e s , or ~oughlgr3 x 1 0 5 c i per ft' of metal s ~ ~ f a tchea t had been exposea to the f u e l s a l t . (This figure is based on the assPlmptFon t h a t 75% of the noble metals d e p o s i t on metal. s u r f a c e s i n t h e Hoop.) The d e p o s i t e d t e l l u r i u m w i l l b e g e n e r a t i n g i o d i n e , some of which w i l l go i n t o t h e gas 0% a i r c s r n t a ~ t i n gthe surface. ~t B Q ~sec (11.6 days) the c a l c u l a t e d t o t a l r a t e a t which 2.3-hr I s 2 1 i s g e n e r a t e d from 78-lmr T e ow s u r f a c e s i s 2 x 1.06 ~ i / h ror a b o u t 30 C i / h r p e r f t 2of s u r f a c e i n t h e f u e l c i r c u l a t i n g system. ~ight-day 1311 w i l l be geRerated on surfaces at a t o t a l rate C i / h r p e r ft2. sf a b u u t 5 Ci/hr or 7 x

"he noble gases i n the g r a p h i t e after PO days could amount t o as much 86 1.2 X lo6 Ci ( d R C ? s t d l P33Xe) ELSsUlTdng none d i f f u s e d out dUKing the cooling p e r i o d . The s a d i s a c t i v e d a u g h t e r s of noble g a s e s i n the g r a p h i t e would l i k e l y range up to I x I O 7 C1.

The i n v e n t o r i e s of t h e f i s s i o n p r o d u c t s t h a t dominate a t 10 days a f t e r shutdown m y b e as much as E 7 8 t i m e s those i n t h e PISRE. (This f a c t o r m y be c o n s i d e r a b l y lower if t h e MSBR g a s - s t r i p p i n g system removes a s u b s t a n t i a l f r a c t i o n of t h e n o b l e metals.) The m o u n t s p e r u n i t area should be less than 5 t i m e s as g r e a t as in t h e BERE, however." Thus the observed b e h a v i o r of t h e d e p o s i t e d f i s s i o n p r o d u c t s i n the M S E shouBd b e r a t k e ~similar to that to b e expected i n t h e MSBR.

*For t h e s h o r t l i v e d n o b l e metals t h a t

dominant a few days a f t e r shutdown, the i n t e n s i t y on f u e l l o o p s u r f a c e s i s n e a r l y p r o p o r t i o n a l t u t h e r a t i o of p u w e r ts l o o p s u r f a c e area. POP t h e r e f e r e n c e MSBR, t h i s is 2 - 2 5 x l06/5.2 x 10% = 4 3 icw/ft2; for t h e PISRE t h e ratio w a s 7 . 4 x 103/ 8.5 x 182 = 9 kW/ft2.

L...

11-13

Based an t h e M S E e x p e r i e n c e , w e expect t h a t t h e n o b l e metals on s u r f a c e s w i l l b e more o r l e s s a d h e r e n t , dependtng on whether they are on s u r f a c e s i n t h e s a l t loop o r i n t h e off-gas system, b u t t h a t c a r e must be used t o avoid knocking o r s c r a p i n g them o f f . Although t h e r e was u n c e r t a i n t y i n t h e f r a c t i o n of t h e surface-generated i o d i n e t h a t was r e l e a s e d i n t o t h e gas i n t h e M S E , i t i s c l e a r t h a t i n t h e MSBR measures must b e provided t h a t are adequate t o d e a l e t h all of t h e i o d i n e so g e n e r a t e d . The noble-gas d a u g h t e r s in t h e g r a p h i t e w i l l n o t be r e a d i l y t r a n s f e r a b l e , and should cause no contamination problem. The MSBR b u i l d i n g and equipment l a y o u t are intended t o permit s a f e containment of t h e r a d i o a s t i v i t y d u r i n g maintenance. Before maintenance is s t a r t e d , t h e f u e l s a l t w i l l be secured i n t h e d r a i n t m k . (Noarmally i t w i l l b e c i r c u l a t e d f o r several days t o h e l p remove a f t e r h e a t b e f o r e i t is d r a i n e d . ) The system r e q u i r i n g maintenance w i l l then be purged o f r a d i o a c t i v e g a s e s and, if n e c e s s a r y p cooled down. The contafnment c e l l w i l l t h e n be unsealed afld a maintenance s h i e l d s e t up. The c e l l w i l l b e maintained a t a s l i g h t n e g a t i v e p r e s s u r e by an a i r e x h a u s t system. Tools and o t h e r i t e m s p e n e t r a t i n g t h e maintenance s h i e l d w i l l be s e a l e d t o t h e s h i e l d s o as t o minimize a i r leakage f n t o t h e c e l l . (Boots o r gas-buffered seals might be used.) Primary systems w i l l n o t be l e f t open to t h e c e l l l o n g e r than n e c e s s a r y ; i f an equipment i t e m cannot be r e p l a c e d immediately a temporary c l o s u r e w i l l be a p p l i e d i n o r d e r t o minimize both t h e r a d i o a c t i v e contamination of t h e c e l l and t h e i n g r e s s of oxygen and m o i s t u r e i n t o t h e s y s t e m . h%en contaminated i t e m s are removed through t h e s h i e l d , they w i l l be withdrawn i f f t o casks through openings equipped w i t h v a l v e s o r f l a n g e s t h a t w i l l c l o s e t h e r e a c t o r c e l l and t h e cask except d u r i n g t h e t r a n s f e r . G e n e r a l l y , t h e gas streams p a s s i n g through t h e c e l l w i l l be f i l t e r e d , passed through a b s o r b e r s and r e c f r c u l a t e d . Any e x c e s s gas w i l l be s t r i p p e d s f r a d i o a c t i v i t y b e f o r e i t i s discharged t o t h e atmosphere. Items removed from t h e primary system w i l l be r e p a i r e d o r prepared f o r d i s p o s a l i n a h o t c e l l where s i m i l a r p r e c a u t i o n s must be observed. A l l o p e r a t i o n s w i l l be c a r r i e d o u t i n s i d e t h e r e a c t o r b u i l d i n g t o a s s u r e complete containment

... .... cm

The a s s u r a n c e of p u b l i c p r o t e c t i o n d u r i n g maintenance i s comparable t o t h a t d u r i n g o p e r a t i o n , a l t h o u g h t h e Pines of d e f e n s e are d i f f e r e n t . During o p e r a t i o n , t h e f u e l s a l t and h i g h l y r a d i o a c t i v e g a s e s are c i r c u l a t i n g w i t h i n t h e v e s s e l s and p i p i n g , which are i n t u r n doubly c o n t a i n e d , b e i n g i n s i d e s e a l e d c e l l s i n s i d e t h e r e a c t o r b u i l d i n g . During maintenance, t h e f u e l s a l t w i t h most of t h e f i s s i o n p r o d u c t s w i l l be s e a l e d i n t h e d r a i n t a n k , and t h e p r e c a u t i o n s t h a t e n s u r e t h a t i t w i l l n o t be brought out d u r i n g t h e maintenance o p e r a t i o n s c o n s t i t u t e primary c o n t a i n ment f o r i t . Any system t o be opened w i l l be d r a i n e d and purged s o t h a t when i t i s f i n a l l y opened, t h e amount o f r a d i o a c t i v i t y t h a t could conc e i v a b l y escape i n t o t h e c e l l w i l l be f a r less than t h a t c i r c u l a t i n g (and l i a b l e t o b e i n g s p i l l e d through a p i p e r u p t u r e i n t h e design-basis a c c i d e n t ) d u r i n g o p e r a t i o n . The f i r s t l i n e of d e f e n s e ("primary c o n t a i n ment") f o r t h i s limited amount of r a d i o a c t i v i t y is the v e n t i l a t i o n system t h a t m a i n t a i n s t h e c e l l s a t a n e g a t i v e p r e s s u r e and removes any r a d i o a c t i v e contaminants from t h e exhaust stream b e f o r e i t i s d i s c h a r g e d i n t o t h e r e a c t o r b u i l d i n g . Secondary containment d u r i n g maintenance i s t h e same as d u r i n g o p e r a t i o n - t h e s e a l e d r e a c t o r b u i l d i n g .

1P-l.4

11.3.2.3

A f t e ~ h e a tc o n s i d e r a t i o n s

The f F s s i o n p r o d u c t s t h a t w i l l remain i n t h e g r a p h i t e and on surfaces in t h e f u e l system w i l l produce s i g n i f i c a n t h e a t i n g i n t h e l a r g e equipment items w h i l e maintenance o p e r a t i o n s are going on. This must b e taken i n t o account i n t h e p r o v i s i o n s f o r the major o p e r a t i s n s : r e p l a c e ment of the core g r a p h i t e , t h e tube b u n d l e of a primary h e a t exchanger, and perhaps t h e r o t a r y element of a p r i m a r y pump. ~t is estimated t h a t 1 0 6 seconds (11.6 d a y s ) a f t e r shutdown from 2250 Mw(t) t h e t o t a l heat g e n e r a t i o n r a t e i n t h e primary system would b e 970 kW, c o n s i s t i n g of 210 kW i n t h e g r a p h i t e of t h e c o r e , 125 k&J i n each of t h e f o u r primary h e a t exchangers, and 40 kW d i s t r i b u t e d o v e r the s t h e r s u r f a c e s . What t h e temperature i n t h e primary system must b e b e f o r e i t i s opened has n o t been determined. With t h e c e l l c o o l i n g system t h a t i s e n v i s i s n e d , t h e f u e l system temperature 10 days a f t e r a s h ~ t d ~ m would l i k e l y b e i n t h e range o f 588 to 10BcboP. If f u r t h e r s t u d y of t h e maintenance procedures i n d i c a t e s t h a t t h i s would b e unacceptable , addit i o n a l h e a t removal m u s t b e p r o v i d e d , a d d i t i o n a l time allowed to reach a s a t i s f a c t o r y t e m p e r a t u r e , QT m o r e l i k e l y , l o c a l c o o l i n g would b e employed t o lower t h e temperatue a t t h e p o i n t of c r i t i c a l o p e r a t i o n s t o 200 t o 400°F. Some c o o l i n g must b e continued while t h e i t e m i s b e i n g removed, b u t t h e r a t e of temperature r i s e i n t h e absence of c o o l i n g would b e l o w - 30"F/hr f o r a h e a t exchanger bundle and 2.CsBP,hr f o r t h e g r a p h i t e core. The t e m p e r a t u r e s of t h e p i p i n g and r o t a r y element of would rise even more slowly.

11.3.2.4

G r a p h i t e replacement

Because of n e u t r o n i r r a d i a t i o n damage, i t will b e n e c e s s a r y t o r e p l a c e t h e c o r e g r a p h i t e several t i m e s d u r i n g t h e l i f e of an MSBR p l a n t . Guns i d e r a t i o n of t h e e f f e c t s on b r e e d i n g and p o s s i b l y on power d i s t r i b u t i o n leads t o removal of the g r a p h i t e whli1e i t i s s t i l l s t r u c t u r a l l y sound. Thus, although t h e removal procedure must b e capable o f d e a l i n g with broken g r a p h i t e elements, t h e s t r e n g t h of t h e r a p h i t e s h o u l d n o t hamper i t s removal. I n t h e BmL r e f e r e n c e

MSBR,6 the upper head of t h e reactor vessel and the e n t i r e core (176 toms of g r a p h i t e and 97 t o n s of m e t a l ) a r e r e p l a c e d as a unit. This c o n s t i t u t e s by f a r the l a r g e s t maintenance t a s k i n this conceptual d e s i g n , and e x p l a i n s same important f e a t u r e s of t h e b u i l d i n g l a y o u t and equipment. The major item o f special. maintenance equipment required f o r the c o r e replacement is a 2B-ft-diam x 40-ft-high s h i e l d e d t r a n s p o r t cask. me carbon s t e e l walls of t h e casle are about 2 i n o t h i c k , which i s s u f f i c i e n t t o reduce t h e r a d i a t i o n l e v e l on cont a c t with t h e outside of the cask t o about 31000 R / h r and a t t h e o u t s i d e wall of t h e r e a c t o r containment vessel t o less t h a n 0 . 1 R / h r after's l0-day decay p e r i o d f o r t h e c o r e . Conservative estimates i n d i c a t e t h a t t h e 218 kW of heat b e i n g generated Fn t h e core can b e s a f e l y d i s s i p a t e d through t h e cask wall s o that no cooling system f o r t h e cask w i l l b e seqklired. me 9ea@tOr COP@ ZSSE9Ilbly iS prepared f o r X 2 l t a O V d i n 8

11-15

s e m i d i r e c t fashism through a work s h i e l d . The lifting s f t h e c o r e assembly i n t o t h e t r a n s p o r t cask and t r a n s p o r t t o t h e spent-core s t o r a g e c e l l , t h e i n s t a l l a t i o n of t h e new core assembly, and t h e replacement of t h e s h i e l d i n g are accomplished from t h e remote maintenance c o n t r o l room i n t h e same f a s h i o n as t h e removal and replacement of l a r g e i t e m s of MSKE equipment. Services and t h e i r a s s ~ c i a t e si n an i n d u s t r i a l design s t u d y carried out under s u b c o n t ~ a e tt o O W L q u e s t i o n e d t h e d e s i r a b i l i t y and p r a c t i c a l i t y of r e p l a c i n g the c o r e g r a p h i t e as a u n i t . They i - n v e s t i g a t e d making t h e CQR of i n d i v i d u a l l y r e p l a c e a b l e elements, and decided t h a t 15-i.n. hexagonal elements w e r e t h e o p t i m m . 7 some o f t h e g r a p h i t e elements would b e r e p l a c e d a t 4-year i n t e r v a l s , d u r i n g major t u r b i n e g e n e r a t o r o v e r h a u l s . Adoption of t h i s scheme would obviously g r e a t l y a l t e r t h e requirements f o r h a n d l i n g t o o l s and casks f o r t h e exposed g r a p h i t e ; however, a d d i t i o n a l work i s n e c e s s a r y f o r demonstrating t h e f e a s i b i l i t y ~f t h i s approach. %~SCQ

11.3.3

S t a t u s of development work

A s s t a t e d e a r l i e r , t h e MSBR maintenance concept depends upon a c c e s s from above, a system of r e p l a c e a b l e u n i t s , a p p r o p r i a t e d i s c o ~ n e c t sand t o o l s t o o p e r a t e them, and l i n e s which can b e c u t and rewelded remotely. Thus, i t i s c l e a r l y e s s e n t i a l t h a t maintenance d e s i g n and development be conCUKE^^ w t t h p l a n t d e s i g n . This h a s been t h e case i n the conceptual s t u d i e s t o d a t e e The maintenance techniques for f l u i d - f u e l r e a c t o r s have evolved as t h e s i z e , complexity, and r a d i a t i o n l e v e l s of t h e r e a c t ~ r s have i n c r e a s e d . Design s t u d i e s have n o t i n d i c a t e d any insurmountable problem i n m a i n t a i n i n g a lOOQ-Kd(e) MSBR, and no s e r i o u s c o n f l i c t s have a r i s e n i n imposing t h e maintenance requirements on t h e reactor system.

.....

... ,.:.m

.:. . ......

:.:&

... ... .$&

.... ..frLs ...

... ........ /

... ..;<.:.> .-

....

*:g<;

H o s t of t h e t e c h n i q u e s and many of t h e t o o l s have been developed. S e v e r a l f l e x i b l e maintenance shields have been b u i l t and used. O p t i c a l viewing equipment - window inserts, periscopes, adequate l i g h t i n g - a l l are a v a i l a b l e . The use of a s h i e l d e d maintenance control room w i t h windows, remotely-operable TV, and r e m o t e l y - e o n t ~ ~ l l e cdr a n e and t o o l i n g h a s been s u c c e s s f u l l y demonstrated. Remotely-operable d i s c o n n e c t s f o r e l e c t r i c a l power, i n s t r m e n t a t i s n , slnd service p i p i n g are a t a satisfact ~ sq t a t e 0 % development. The remote f a b r i c a t i o n of b r a z e d j o i n t s i n s m a l l system p i p i n g h a s been demonstrated i n connection w i t h t h e MSREa2 Tko important t e c h n i q u e s t h a t are r e q u i s i t e s f o r m a i n t a i n i n g l a r g e power r e a c t o r s are n o t a v a i l a b l e , however. Tfaey are remote welding and p o s t maintenance i n s p e c t i o n . It is highby d e s i r a b l e from the ~ t i l ~ n d p ~ of i n tr e l i a b i l i t y t h a t t h e S B R fuel c i r c u l a t i o n system b e of all-welded c o n s t r u c t i o n , Thus, remote c u t t i n g and rewelding of t h e system p i p i n g w i l l b e r e q u i r e d i n t h e replacement of major components. The s t a t u s of remote welding as of 1969 and t h e r e q u i r e d development program were p r e s e n t e d i n r e f e r e n c e 8.

11-E6

A p o r t i o n of t h a t program h a s been accomplished and t h e p r e s e n t g e n e r a t i o n of a u t o m a t i c welding machines are reliabeb%eand c a p a b l e of making highq u a l i t y welds,9 These n a c h i n e s a r e not ROW c a p a b l e of f u l l y remote welding, b u t appear t o be a d a p t a b l e t o t h i s purpose.

The p r o v i s i o n s i n the MSBR f o r access t o equipment f o r maintenance o p e r a t i o n s are e q u a l l y a p p l i c a b l e t o i n - s e r v i c e i n s p e c t i o n . The s t a t e of-the-art of remote i n s p e c t i o n of welded j o i n t s i s reviewed i n r e f e r e n c e 18. Dependable a p p l i c a t i o n sf comon methods f o r n o n d e s t r u c t i v e inspect i o n of welds is d i f f t c u l t o r impossib1e i n high-temperature, highr a d i a t i o n f i e l d s . Some methods promise t o be s u c c e s s f u L , however, and c u r r e n t AEC and i n d u s t r i a l programs a r e developing equipment, manipulat o r s , and i n t e r p r e t i v e methods f o r a c o u s t i c m i s s i o n and u l t r a s o n i c holography ~ ~ ~ n i t o r and i n g i n s p e c t i o n . These programs are expected t o culminate i n remote i n s p e c t i o n methods f o r r e a c t o r welds which should be a d a p t a b l e t o MSBR c o n d i t i o n s and needs. The equipment and techniques f o r remote r e p a i r do n o t exist; however, much of t h a t development as w e 1 1 as t h e i n s p e c t i o n development i s Fnterchangeable w i t h remote welding development.

It i s h i g h l y important t h a t r a ~ t maintenance e be given a d e q u a t e consideration d u r i n g t h e p r e l i m i n a r y and conceptual d e s i g n s t a g e s f o r moltens a l t r e a c t o r s i n o r d e r t h a t (1) t h e r e q u i r e d maintenance technology can be i d e n t i f i e d , (2) p r o v i s i o n s f o r remote maintenance requirements can be p r o p e r l y i n c o r p o r a t e d i n t h e d e s i g n of r e a c t o r s and componentsg and ( 3 ) improved estimates of t h e c o s t of remote maintenance can be developed.

11.4.1

Objective

The o b j e c t i v e s of work i n t h i s task group are t o develop a maintenance approach t h a t i s c o n s i s t e n t w i t h t h e o v e r a l l d e s i g n o b j e c t i v e s f o r t h e MSBW, and t o i d e n t i f y t h e r e q u i r e d maintenance technology which will a l l o w r e l i a b l e remote maintenance of MSBRrs a t an a c c e p t a b l e c o s t .

The s c h e d u l e f o r work In t h i s t a s k group i s shorn i n Table 11.4.2.

11 4 e 3

Funding

The o p e r a t i n g fund requirements f o r work i n t h i s t a s k group are s h m i n Table 11.4.3.

u..

k . . .

Table

11.4.2.

Schedule maintenance

for mrk in Task during preliminary

Group 18.1 - Consideratian and conceptual design

Fiscal

10.1.1

Remote design 10.1.1.1

10.1.1.5

maintenance for lOOO-M(e) reference MSBW General survey of MSBR maintenance needs Maintenance requirements for individual components Determination of required maintenance functions Determination of design restrictions resulting from maintenance requirements Estimation of impacts on performance

10.1.2

Remote

maintenance

10.1.3

Remote lO.1.3.1

maintenance for Determination requirements Determination functions

10.1.1.2 lO.1.1.3 10.1.1.4

10.1.3.2

for

demonstration

required

year

4 fI I -- --^_._-. i ---____

reactor

test reactor of MSTR maintenance af

remote

maintenance

Table

11.4,3. operating fund sf remte maintenance

Pequirements fQH Task Group 10.1 during pr&khinary and conceptual. (costs in 1000 dallars)

- Consideration design

Fiscal 1977

10.1.1

19 79

19 80

Remote maintenance for lOQO-MM(e)reference design MSBR 10.a *l* 1 General survey af MSBRmaintenance X-E?CYilS

10.1.l.2

10.1.11.5

Maintenance KequiPements for individual components Deterdnatian af required maintenance f?mctions Detemination of design Pestslctions resulting fram maintenance KeqniKements Estimatisn of impacts on performance

Subtotal

10.1.1

10.1.2

Remote

maintenance

10.1.3

Remte 10.1.3.1

maintenance for Determination requirements Determination functions

10.1.1.3 10.1.1.4

10.1.3.2

Subtotal Total

1978

year

operating

for

demonstration

for

Task

10 5 50

10 5 15

test reactor of MSTR maintenance of

required

10.1.3 fauads

reactor

Group

10.1

40 __ 100

5 35 50

maintenance

1981

11-19

11.4.4

Task 1 0 . 1 . 1 MSBR

Remote maintenance for 1086-MW(e) r e f e r e n c e d e s i g n

Although mny a s p e c t s of remote maintenance development €01- a 1000-Pa9Qe) MSBR must b e c a r r i e d o u t during t h e f i n a l s t a g e s of d e s i g n f o r a p a r t i cular r e a c t o r , a n d e of ~ i m p o r t a n t factors must b e considered d u r i n g t h e p r e l i m i n a r y and conceptual d e s i g n s t a g e s i n order t h a t a c o n s i s t e n t approach can be adopted f o r d e m n s t r a t i o n and t e s t r e a c t o r s , and i n o r d e r t h a t t h e r e q u i r e d maintenance technology c m be i d e n t i f i e d and developed i n a t i m e l y manner. Work i n t h i s t a s k w i l l c o n s i s t of a general sura$ey of E B R maintenance needs d u r i n g the p r e l i m i n a r y conceptual d e s i g n s t a g e , i d e n t i f i c a t i o n of maintenance requirements for i n d i v i d u a l components as t h e c ~ n ~ e p t ud eds i g n f o r t h e r e f e r e n c e MSBR i s d e f i n e d s u f f i c i e n t l y , d e t e r m i n a t i o n of t h e r e q u i r e d remote and semiremote maintenance funct i o n s , d e f i n i t i o n of r e s t r i c t i o n s on t h e ~efereneed e s i g n which result from maintenance ~ e q u i ~ e ~ ~ eand n t sevaluation , of t h e fmpacts of maintenance on the economic and n u c l e a r performance of the r e f e r e n c e d e s i g n MSBR e

11.4.4.l

. s .

... ....

..... .:-

.... . ::a

General s u r v e y of MSBR maintenance needs

Work i n t h i s s u b t a s k w i l l c o n s i s t of a review of p r e v i o u s work on %emote maintenance f o r MSBRs and an e x t e n s i o n of p r e v i o u s work as n e c e s s a r y t o proaride a g e n e r a l d e s c r i p t i o n o f maintenance requirements f o r MSBRs. Many aspects of c u r r e n t MSBR r e f e r e n c e design are s u f f i c i e n t l y complete f o r work in this subtask, and t h e remaining aspects w i l l have been d e f i n e d by the end of FY 11978 (see Sectisn 8). The maximum temgeratures and r a d i a t i o n i n t e n s i t i e s under which the v a ~ i o u smaintenance o p e r a t i o n s would be c a r r i e d out w i l l b e i d e n t i f i e d . The work w i l l also determine which components are t o b e replaced and which w i l l b e repaired i n place. The extent of p r i m a r y - c i r c u i t cell cooldown n e c e s s a r y f o r the v a r i o u s maintenance o p e r a t i o n s w i l l . b e d e f i n e d , and an overall maintenance plail~sogshy w i l l b e developed. The work will also de te r nine where f n t e r connects and maintenance-related pipe c u t s and welds w i l l be made.

11.4.4.2

... ...,

Subtask 60.1.1.1

Subtask 10.1.1.2 COlaapOnentS

Maintenance requirements f o r i n d i v i d u a l

Work i n this subtask will determine t h e p r o b a b l e maintenance requirements f o r i n d i v i d u a l components f o r t h e refe~enced e s i g n MSBR. R e m o t e maintenance technibques will. b e developed f a r each component i n c l u d i n g methods foP in-service i n s p e c t i o n , b r e a k i n g of component d i s s s n n e c t s and optimum l o c a t i o n of p i p e cuts, methods f o r component support and t r a n s p o r t d u r i n g maintenance, t e c h n i q u e s f o r component i n s p e c t i o n i n o r d e r t o detemtne whether r e p a i r o r d i s p o s a l of a component w i l l be e f f e c t e d , methods ~ O K p r e c i s e p o s i t i o n i n g of each replacement component, techniques f o r making up d i s c o n n e c t s , and methods for remote p i p e welding and weld inspection.

11-20

11.4.4,3

Subtask 10.1.1.3 Determination of required maintenance functions

Based on work described in Subtasks 18.31.1.1 and 10.1.1.2, a determination will be made of the probable maintenance functions which will be required f o r remotely maintaining an NSBR, and of the l i k e l y conditions, i n c l u d i n g temperature and radiation level, under which these functions must be carried o u t . The aim of this s u b t a s k will be to categorize maintenance functions in a mnner which shows clearly not only the t y p e of function b u t the range of variables which must be considered such as pipe diameter, w a l l thickness, a l l o w a b l e work space? degree of visibility, etc. 11.4.4.4

Determination of design restrictions resulting from maintenance requirements

Subtask 18.1.1.4

Work in t h i s s u b t a s k w i l l determine the design restrictions which are necessary for the reference design MSBW as a result of maintenance requirements and w f l % identify any locations where maintenance sonsiderat i o n s dictate modification o f the reference design.

11.4.4.5

Subtask 10.1.1.5

Estimation of impacts of maintenance economic and nuclear performance of %000-MW(e) MSBR

QH~

Work in t h f s subtask w i l l be aimed at obtaining an improved estimate of the impacts sf remote maintenance on the economic and nuclear performance of the reference design l000-MW(e) ?GBR. If maintenance o p e r a t i o n s are i . d e n t i f i e d which result in unacceptable nuclear or economic impacts,

alternate maintenance approaches and design changes will be evaluated. 11.4.5

Task 10.1.2

Remote ma~ntenancefor demonstration reactor

AS disc~ssediin Section 8 ( s u b t a s k 7.1.1.7), after the reference design for the 100Q-rn(e) MSBR has been sufficiently well defined, a preliminary conceptual d e s i g n w i l l 1 be prepared for a demonstration reactor which will ultimately provide the experience necessary for design of c o m r c l i a % reactors. Work will be carried out in this task during development of the preliminary csnceptuaP design for the demonstration reactor to ensure that the additional whtertance technology, if any, required f a r t h e demonstration reactor is identified, and to ensure that the maintenance approach f o r the demonstration reactor w i l l resemble as c l o s e l y as is practical that f o r the reference design MSBR. The general a p p r ~ a e kto be followed in this task will be s F m i P a ~to that outlined in Subtasks 10.%.2.1 thrsugkn 10.1.2.4. H O W e V e % , S h C e the COHnceptUal deSfm f o r the demonstration reactor w i n not be investigated as f u l l y as the %080-rn(e) MSBR reference design, there will be a c~~~esponding reduction in the extent to which remote maintenance considerations are devel~ped f o r the demonstration reac %: o r e

11-21

11.4.6

Task 1 0 . 1 . 3

Remote maintenance f o r test r e a c t o r

As d i s c u s s e d i n S e c t i o n 8 (Tasks 7 . 1 . 3 and

7.1.4), a f t e r t h e c o n c e p t u a l d e s i g n s f o r the lOOO-MW(e) r e f e r e n c e d e s i g n PISBR and a demonstration r e a c t o r have been d e f i n e d s u f f i c i e n t l y , a c o n c e p t u a l d e s i g n w i l l b e developed f o r a test reactor which would provide the technology KgqUiKed f o r d e s i g n of the demonstration r e a c t o r . Work i n t h i s t a s k w i l l c o n s i s t of determining t h e maintenance requirements for t h e test r e a c t o r a d f o r the i n d i v i d u a l components t h a t w i l l c o n s t i t u t e t h e t e s t r e a c t o r , d e t e r ote functions, Enination of t h e r e q u i r e d remote and s e m i r e ~ ~ ~ maintenance and d e f i n i t i o n of r e s t r i c t i o n s on t h e test r e a c t o r d e s i g n which result from maintenance requirements. An important f u n c t i o n of this t a s k w i l l be t h e i d e n t i f i c a t i o n of any c r i t i c a l maintenance technology r e q u i r e d f o r d e s i g n of t h e demonstration r e a c t o r which w i l l n o t b e provided by the test r e a c t o r . 11.4 6 l e

Subtask 1Q.1 3 1 e

Determination of NSTR maintenance requirements

Work i n t h i s s u b t a s k will be aimed a t determining the maintenance r e q u i r e ments f o r t h e t e s t r e a c t o r , r e t a i n i n g t o the e x t e n t p r a c t i c a l t h e mintenance approach and t e c h n i q u e s r e q u i r e d f o r t h e demonstration r e a c t o r and t h e lOQQ-W(e) r e f e r e n c e d e s i g n MSBR. The maximum temperatures and r a d i a t i o n i n t e n s i t i e s under which t h e maintenance o p e r a t i o n s w i l l be c a r r i e d out w i l l b e i d e n t i f i e d . The work w i l l d e f i n e t h e probable maintenance requirements f o r t h e i n d i v i d u a l components of the t e s t r e a c t o r . Remote maintenance t e c h n i q u e s w i l l b e developed f o r each component i n disc l u d i n g methods for i n - s e r v i c e i n s p e c t i o n , b r e a k i n g of compo~~ena: connects and optimum l o c a t i o n of p i p e c u t s , methods f o r component s u p p o r t and t r a n s p o r t d u r i n g maintenance, methods f o r p r e c i s e p o s i t i o n i n g of each replacement component, t e c h n i q u e s f o r making up d i s c o n n e c t s , and methods f o r remote p i p e welding and weld i n s p e c t i o n .

11.4.6.2

Subtask 10.1.3.2 functions

Determination of r e q u i r e d maintenance

"he work d i s c u s s e d i n Subtask P 8 . 1 . 3 . 1 w i l l serve as t h e b a s i s f o r def i n i n g t h e p r o b a b l e maintenance f u n c t i o n s f o r t h e test r e a c t o r , and t h e c o n d i t i o n s under which t h e maintenance o p e r a t i o n s will b e c a r r i e d o u t . The maintenance f u n c t i o n s w i l l be c a t e g o r i z e d i n o r d e r t o show clearly t h e t y p e s of maintenamce f u n c t i o n s r e q u i r e d , and t h e range of maintenance parameters which m w t b e covered. The r e s u l t i n g requirements w i l l b e compared w i t h t h o s e e s t a b l i s h e d f o r t h e demonstra%isn r e a c t o r and t h e lOQO-MW(e> r e f e r e n c e d e s i g n MSBR in o r d e r t o i d e n t i f y those r e q u i r e m e n t s , i f any, which fa11 o u t s i d e t h e p r e v i o u s l y e s t a b l i s h e d requirements. A composite l i s t of maintenance f u n c t i o n s i n c l u d i n g t h e r e q u i r e d ranges of maintenance-related parameters w i l l b e developed which w i l l s e n e as the basis f o r development of ESR maintenance technology. ..... m

52.3

.... ..... ..A. "C,,

11-22

11 5

TASK GROUP 1 0 2 a

BEVELQPPfENT OF EaEMQTE PfAENTENANCE TECHNOLOGY

In m o l t e n - s a l t r e a c t o r systems , maintenance of components of t h e primary c i r c u i t w i l l b e e f f e c t e d by u s i n g remotely o p e r a t e d t o o l s and equipment. System components, s u c h as pumps, heat e x c h a n g e r s , and valves w i l l b e r e p l a c e d by remotely b r e a k i n g d i s c o n n e c t s and c u t t i ~ gp i p e c o n n e c t i o n s , r e p l a c i n g the component , remaking d i s c o n n e c t s and making remote p i p e w e l d s , and i n s p e c t i n g t h e welds by remote t e c h n i q u e s . Remote maintenance r e q u i r e s s u i t a b l e equipment f o r v i e w i n g and i n s p e c t i o n of equipment and s y s t e m s at t e m p e r a t u r e s in t h e r a n g e of 500 t o %000"F in the p r e s e n c e of r a d i a t i o n l e v e l s of a b o u t I O 5 R / h r . L o c a l c o o l i n g can p r o b a b l y b e employed t o lower t h e t e m p e r a t u r e t o 206 t o 4 0 Q " F . The main s t e p s i n remote r e p l a c e m e n t of components w i l l be cuttring p i p e c o n n e c t i o n s and b r e a k i n g d i s c o n n e c t s , s p r e a d i n g t h e p i p e e n d s t o p r o v i d e c l e a r a n c e f o r component removal, and t r a n s p o r t i n g t h e component from t h e c e l l . I n s t a l l a t i o n of a new o r r e p a i r e d component will i n v o l v e t h e s t e p s of m a i n t a i n i n g c l e a n l i n e s s c o n t r o l , t r a n s p o r t i n g t h e r e p l a c e m e n t component t o its i n - c e l l l o c a t i o n , a l i g n i n g t h e component and p i p e ends f o r w e l d i n g , t a c k w e l d i n g t h e p i p e ends t o m a i n t a i n a l i g n m e n t d u r i n g f i n a l c l o s u r e w e l d i n g , and remotely inspecting the w e l d to ensure that q u a l i t y and r e l i a b i l i t y s t a n d a r d s have been m e t . Many m a i n t e n a n c e o p e r a t i o n s will b e u n d e r t a k e n as a ~ ~ n s e q u e n cofe i n c i p i e n t f a i l u r e d e t e c t i o n d u r i n g o p e r a t i o n o r i n - s e r v i c e i n s p e c t i o n , and the d e t e c e i o n of i n c i p i e n t failures i s a p a r t of t h i s t a s k g r o u p , In some situations, in s i t u r e p a i r may be p r e f e r r e d o v e r component removal and replacement

11.5.1

Objective

The o b j e c t i v e of work in this task group is the development of technology r e q u P r e d f o r remote maintenance of ~ ~ o l t e n - s a lreactors t as i d e n t i f i e d by work i n S u b t a s k 10.1.3.2, and by s u b s e q u e n t e x p e r i e n c e on t h e d e s i g n , fabrication, and o p e r a t i o n of components and s y s t e m s f o r m o l t e n - s a l t reactors

11.5 2 D

Schedule

The s c h e d u l e f o r work i n t h i s task group i s shorn i n T a b l e 11.5.2,

11 5 * 3 e

Funding

O p e r a t i n g fund r e q u i r e m e n t s for this t a s k group are shown i n T a b l e 11.5.3.1, and c a p i t a l equipment fund r e q u i r e m e n t s are shown i n T a b l e C a p i t a l equipment f u n d s i n the m o u n t of $2g60,000 will be 11.5.3.2. r e q u i r e d i n Fp 1978 f o r t h e d e s i g n and e o n s t m e t i o n of a Maintenance Development F a c i l i t y .

Tab%@ 11.5.2.

Schedule

~QP wonrt IQ Task Gmq

10.2 - Deve%opment

1979 P0.2.f

Deve%opnlent of improvadtiewing devices

%0.2.2

Development equipment

10.2.3

Development of sea% weld weldflng equipment

1802.4

Deve%opent tecbwiques

10.2.5

Development of pipe alignment technology

10.2.6

Development techniques

of renrnote pipe

of preweld

of remote

cutting cuttim

and

cleaning

spreading pipe

and welding

1980

of equipment

for

Fiscal

year

31982

remote

1983

maintenance

10.2.3

Development

of s&L

weld

cutting

10.2.4

Developmnt techtiques

and 20

Wd.dfng

sf preweld

IQ0

96 336

280 650

150 497

150 ~ 448

150 436

130 385

cleaning

35 88

Table 11.5.3.2.

Capital

equipment fund requirements for Task Graup 10.2 - Development of equipment for remote maintenance (casts in 1000 dollars) Fiscal 1977

10.2

Total

1978

Maintenance Development Facility 10.2.1 Development of improved viewing devices 10.2.2 Revelopment of remote pipe cutting equipment 18.2.3 Development of seal weld cutting and welding equipment 10.2.4 Development of preweld cleaning techniques 10.2.5 Development of pipe spreading and alignment technology 10.2.6 Development of remote pipe welding techniques

200

capital

200

equipment funds foaf Task Group 10.2

1979

1980

year

1981

1982

1983

1984

15 15

50 85

50 90

A cn

11-26 11 5 4 e

Facilities

M o l t e n - s a l t b r e e d e r r e a c t o r s and t e s t r e a c t o r s t h a t p r e c e d e them w i l l r e q u i r e development of methods and equipment f o r remote maintenance o f the h i g h l y r a d i o a c t i v e r e a c t o r p r i m a r y and a u x i l i a r y s y s t e m s . A f a c i l i t y w i l l b e r e q u i r e d i n which t h e methods and equipment can b e t e s t e d on mock-ups of reactor s y s t e m s . No f a c i l i t y p r e s e n t l y e x i s t s i n whfch s u c h t e s t s could b e made. A Maintenance Development F a c i l i t y w i l l b e c o n s t r u c t e d which w i l l c o n s i s t i n i t i a l l y of a mock-up of p a r t s of a r e a c t o r c e l l and an a u x i l i a r y e q u i p ment c e l l , mock-ups of p a r t s of t y p i c a l r e a c t o r and a u x i l i a r y equipment and p i p i n g systemss some a u t o m a t i c c u t t i n g , w e l d i n g , and p o s i t i o n i n g equipment and equipment n e c e s s a r y f o r h a n d l i n g remote maintenance t o o l s . T h i s f a c i l i t y w i l l b e i n s t a l l e d i n an e x i s t i n g b u i l d i n g . I n i t i a l l y , the ~ r o r ki n t h e f a c i l i t y w i l l be concerned w i t h a d a p t i n g t h e a u t o m a t i c c u t t i n g , w e l d i n g , and positioning equipment f o r remote o p e r a t i o n and d e m o n s t r a t i n g t h o s e o p e r a t i o n s on a s i m u l a t e d r e a c t o r system. A s d e s i g n s are e v o l v e d f o r r e a c t o r equipment, models of t h e equipment w i l l b e i n s t a l l e d i n t h e c e l l s , and methods for m a i n t a i n i n g t h e equipment w i l l b e t e s t e d and improved. I t i s a n t i c i p a t e d t h a t much of t h e r e a c t o r maintenance w i l l have t o b e done a t t e m p e r a t u r e s of 206 to 36Q"G and w i t h s p e c i a l v e n t i l a t i o n . P a r t of t h e f a c i l i t y w i l l b e equipped f o r c o n d u c t f n g m a i n t e n a n c e tests a t e l e v a t e d t e m p e r a t u r e s . T h i s a c t i v i t y will r e q u i r e o b l i g a t i o n of $200,000 in c a p i t a l equipment f u n d s d u r i n g FY 1978.

Subsequent development work on remote maintenance t e c h n i q u e s f o r a mslfens a l t t e s t r e a c t o r w i l l be c a r r i e d o u t i n t h e ~ z o l t e n - s a l t t e s t r e a c t o r mockup (see S e c t i o n 1 3 ) .

11.5.5

Task 1 0 . 2 . l

Development of improved viewing d e v i c e s

Work i n t h i s t a s k w i l l b e concerned w i t h t h e development s f improved viewing d e v i c e s f o r remote maintenance application^. The use of m i r r o r s has been b e n e f i c i a l i n many a p p l i c a t i o n s , and commercially a v a i l a b l e p e r i s c o p e s , omniscopes, t e l e s c o p e s , and f i b e r o p t i c s equipment have been used f o r a v a r i e t y of meeds in n o m i n a l - r a d i a t i o n and h i g h - t e m p e r a t u r e environments a s s o c i a t e d w i t h r e a c t o r r e p a i r and h o t cell work. The a p p l i c a t i o n of f i b e r o p t i c s d e v i c e s t o o b s e r v a t i o n s i n areas where access l i m i t a t i o n s 0% o b s t r u c t i o n s p r e v e n t the u s e of c o n v e n t i o n a l v i e w i n g equipment i s r e l a t i v e l y new, and work i n t h i s t a s k group w i l l c o n s i s t of a s u r v e y of f i b e r o p t i c s a p p l i e a t f o n s and a v a i l a b i l i t y i n o r d e r t o i d e n t i f y p o t e n t i a l a p p l i c a t i o n s of s u c h d e v i c e s to remote maintenance o p e r a t i o n s , and t o r e c o r n e n d a d d i t i o n a l work i n areas s f p r o m i s e .

Work i n this t a s k group w i l l a l s o i n c l u d e a survey of r a d i a t i o n and h i g h - t ~ m p e r a t u r e - r e ~ i ~t etl~e ~v i~s i o n equipment, and procurement and t e s t i n g of equipment which a p p e a r s s u i t a b l e i n o r d e r t o e v a l u a t e t h e need f o r a d d i t i o n a l development work i n t h i s area.

I " .

11-27

11.5.6

Task 18.2.2

Development of remote pipe c u t t i n g equipment

Considerable e x p e r i e n c e h a s been developed a t CENL on t h e development and rase of automated, o r b i t a l p i p e c u t t i n g machinery as p a r t sf a f e a s i b i l i t y s t u d y f o r t h e MSR maintenance program. Machining heads were shown t o be capable of c u t t i n g p i p e , trimming the ends s q u a r e , a d preparing end b e v e l s on s c h e d u l e 40 s t a i n l e s s s t e e l p i p e i n s i z e s up t o 6 i n . w i t h l i t t l e d i f f i c u l t y . Problems a r o s e i n c u t t i n g Enconel because of i t s work-hardening t e n d e n c i e s , which are s h i l a r t o t h o s e of HasteHloy R . A d d i t i o n a l d i f f i c u l t i e s are a n t i c i p a t e d f o r p i p e s i z e s l a r g e r than 6 i n . s i n c e t h e c u t t i n g o p e r a t i o n s are slow, c u t t e r f e e d rates are minimal, and c u t t e r s d u l l r a p i d l y and r e q u i r e f r e q u e n t replacement. Observations i n d i c a t e d that the c a r r i a g e d r i v e i s t h e l i m i t i n g f a c t o r on c u t t i n g ability. Improvements are r e q u i r e d Its p r o v i d e a s t r o n g e r and more p o s i t i v e c u t t e r depth c o n t r o l and mare s t a b l e l o n g i t u d i n a l a d j u s t m e n t s A s p l i t - b e a r i n g s l e e v e c a r r i a g e w a s proposed f o r development which c ~ ~ l d be i n s t a l l e d remotely and used f o r i n - c e l l p i p e c u t t i n g . a

a ...

C o m e r c i a l l y a v a i l a b l e pipe c u t t i n g equipment zppears t o b e a d a p t a b l e t o remote p i p e c u t t i n g ; however, c o n v e n t i o n a l equipment r e q u i r e s conside r a b l y g r e a t e r c l e a r a n c e t h a n equipment developed by OBIR'E. C u r r e n t l y , work is underway a t t h e Banford Engineering Development Laboratory € o r development of equipment for r e ~ o t e l yc u t t i n g and welding of t h e openand closed-Poop r e a c t o r top c l o s u r e s f o r removal and r e i n s t a l l a t t o n of e x p e r i m e n t a l assemblies. %he equipment, which i s a p p l i c a b l e t o r e l a t i v e l y s m a l l (6072-in. wean d i m ) p i p e , i s b e i n g t e s t e d a t temperatures as high as 500'~ and i s designed to withstand exposure t o 105 ~ / h rg a m r a d i a tion. It i s a n t i c i p a t e d t h a t work i n t h i s t a s k w i l l b e n e f i t g r e a t l y f ~ o mt h i s work as w e l l as from advances in c o m e r c i a 1 p i p e c u t t i n g equipment e

Work i n t h i s t a s k w i l l b e d i r e c t e d toward f u r t h e r e v a l u a t i o n and development s%improved c a r r i a g e s i n c l u d i n g t h e s p l i t - s l e e v e type. P a r t i c u l a r a t t e n t i o n w i l l be given to the effect of pipe spring back during the c u t t i n g o p e r a t i o n whish may r e s u l t i n damage t o t h e sleeve end b e a r i n g s . Work w i l l d s o b e c a r r i e d o u t %OK s u r v e y i n g somereialPy a v a i l a b l e equipment and adapting equlpment having p o t e n t i a l .

11.5.7

..%

... ....

: . .. i xi<; .,

...

Task 10.2.3 equipment

Development of seal weld c u t t i n g and w e l d i n g

Work in t h i s task w i l l b e d i r e c t e d t o t h e development of techniques and equipment for t h e remote cutting and welding of seal welds. New t y p e s of c a r r i a g e s and weld-head propuBsion schemes w i l l b e developed for seal weld a p p l i c a t i o n s .

11-28

11.5.8

Task 1 8 . 2 . 4

Developmnt of preweld cleanina t e c k n i a u e s

F i n a l preweld pipe-end p r e p a r a t i o n s i n c l u d e kerf and/or c h i p removal from t h e open ends of t h e p i p e j s l n t , removal of salt from t h e p i p e wall, and t h e i n s t a l l a t i o n of a s u i t a b l e purge block plug i n t o the p i p e n e a r t h e open joint. Acceptable e n ~ i r o n ~ ~ ~off-gas t a l , a i r l o c k , and ventilation c o n d i t i o n s must b e established w i t h i n t h e c e l l . C u t t i n g c h i p s from mechanical sawing, k e r f from plasma %%mec u t t t n g , and s a l t r e s i d u e on t h e p i p e walls a d j a c e n t t o t h e cut j o i n t must b e removed before the i n s t a l l a t i o n of purge blocks o r the t a k i n g of a f a c s i m i l e i n p r e p a r a t i o n f o r final p i p e welding. Work in t h i s task will b e d i r e c t e d to t h e development of prewePd c l e a n i n g t e c h n i q u e s and equipment, and t o development of methods f o r t h e p r o p e r i . n t r O ~ i ~ t i oof n replacement c t ~ ~ ~ p o n e ~xis ~ t ssting . toois ana equipment w i l l be. modified when p o s s i b l e t o p r o v i d e t h e n e c e s s a r y c l e a n i n g a c t i o n .

11.5.9

Task 18.2.5 eq uipmea t

Development sf p i p e s p r e a d i n g and alignment

There is only l i m i t e d experiemce w i t h the use of remotely c o n t r o l l e d equipment f o r spreading the ends of p i p e a f t e r c u t t i n g , p o s i t i o n i n g replacement components i n p r o p e r alignment, and h s 1 d i n g them i n p o s i t i o n d u r i n g welding. Host 0% t h e a v a i l a b l e reaceor maintenance experience relates t o ~ ~ ~ 3 e mmai tn tee~ n m c e , whereas MSBR maintenance m u s t be performed under d r y c o n d i t i o n s . The l i m i t e d d q maintenance e x p e r i e n c e results from work w i t h t h e MSRE mockup and w i t h MSRE maintenance; Enowe v e r , Work i S CUrreIltly UndeXWEiy On Other r e a c t o r Concepts Which ShOUlbd be a p p l i c a b l e in p a r t t o MSBR maintenance requirements. Techniques f o r p i p e alignment were p a r t i a l l y developed as p a r t of t h e Westinghouse ~ e n n s y ~ v a ~power ia ana ~ i g h tcompany study f o r the ~ e n n s ~ i v a n i a Advanced Reactor Program (PAW) d u r i n g t h e l a t e 1956's. Work f n t h i s task would determine p i p e f l e x i b i l i t y ~ e q ~ i r e m and ~ ~ de~ t s f i n e t h e e x t e n t to which p i p e s i z e s , w a l l t h i c k n e s s , l e n g t h , and method of attachment i n f l u e n c e f l e x i b i l i t y . In a t i g h t l y coupled system, such as the r e f e r e n c e d e s i g n 100Q-m(e;B MSBR, f l e x i b i l i t y i s l i m i t e d and it may b e necessary t o use t a i l o r e d s p o o l p i e c e s Par j o i n i n g s h o r t s e c t i o n s of l a r g e diameter p i p e . Anr a n a l y s i s w i l l b e made of a l l i n - c e l l p i p e system f o r a n t i c i p a t e d p i p e d e f l e c t i o n s h i f t s and movements when p i p e s are s e v e r e d d u r i n g maintenance o p e r a t i o n s . The equipment and p i p e s u p p o r t d e v i c e s r e q u i r e d f a r m a i n t a i n i n g alignment, t h e %scations of t h e c u t p l a n e s , and the space r e ~ p i ~ ef od r i n s e r t i o n of p r e s s u r e c y l i n d e r s f o r vfng t h e p i p e ends will b e defined. Taze p o t e n t i a l of s p l i t - b e a r i n g sleeves f o r r e a l i g n i n g p i p e f o r preweld and w e l d tacking assembly w i l l be e v a l u a t e d , and d e v i c e s s f t h i s t y p e w i l l b e developed i f warranted.

.... ....., ~

11-29

16.5.10

Task 10.2.6

Development of remote pkpe w e l d i n g t e c h n i q u e s

work in this task w i l l b e directed toward the development of remote p i p e welding t e c h n i q u e s f o r E B R maintenance. There are c u r r e n t l y a number s f ~ o ~ ~ ~ ~ ~ e ar vcaii a l albll y e a u t o m a t i c welding d e v i c e s , as w e l l as an ORWLdeveloped a u t o m a t i c welder which w i l l a u t o m a t i c a l l y butt-weld p i p e s from 3 to 6 i n . i n diameter having w a l l t h i c k n e s s e s r a n g i n g from 3/16 to 1 . 5 in. The r e s u l t i n g welds have been shown t o m e e t ASXE codes and WDT s t a n d a r d s for n u c l e a r - q u a l i t y gas--tungsten-arc welding of p i p e . P r e s e n t l y , t h e commercial machines must b e mounted on p i p e s maniaally, and o p e r a t o r judgment i s n e c e s s a r y f o r a c h i e v i n g satisfactory o p e r a t i o n . Work i n t h i s task w i l l c ~ n s i s tof s u r v e y i n g t h e commercially a v a i l a b l e d e v i c e s which show the a u t o m a t i c welding d e v i c e s , p r o c u r i n g one o r g r e a t e s t p o t e n t i a l for a d a p t a t i o n t o remote maintenance welding a p p l i c a t i o n s , and c a r r y i n g o u t remote welding tests under simulated remote maintenance c s n d i t i o n s . P a r t i c u l a r a t t e n t i o n w i l l b e given to modificat i o n s necessary f o r e n s u r i n g a d e q u a t e r e s i s t a n c e t o temperatures in the range of 30Q t o 5QO"P and gama r a d i a t i o n levels as h i g h as l o 5 R/hr. TASK GROUP 1 0 . 3 BEXLOPMEm OF EQUIPMENT AND TECHNIQUES FOR POST-WED INSPECTION

131.6

18.6.1

Objective

The o b j e c t t v e of work. i n this t a s k group is t h e development of equipment and t e c h n i q u e s f o r remote i n s p e c t i o n sf welds and welding o p e r a t i o n s during remote maintenance f o r M S B R ~ ~ .

The s c h e d u l e f o r work in this task group i s shown i n T a b l e 11.6.2.

... ,a

Operating fund requirements for t h i s task group are shown i n Table l1.6.3.1, a d capital equipment fund requirements are shorn in Table 11. 6 3 2. D

.... := ...

:....... s&

11.6.4

Facilities

N o a d d i t i o n a l f a c i l i t i e s w i l l b e r e q u i r e d f o r work i n t h i s task group. Part of t h e work w i l l b e c a r r i e d out i n f a c i l i t i e s wed f o r Task Group 10.2.

Table

11.6e2.

Schedule and

far work techniques

in Task GKoup 10.3 - Development for post-weld inspection Fiscal

18.3.1

Inspection

automatic

welder

arecords

10.3 "2

Maptatian methods 10.3.2.1 10.3.2.2 10.3.2.3

customary

we1a

inspec$ion

10.3.3

Liquid penetrant examination Radiographic examination Ultrasonic examination

Development of advanced methods for weld inspectisn 10.3.3.1 Eddy current examination 10.3.3.2 Acoustic emission techniques

0-f equipment

yeas

Table

11.6.3.1.

Operating

fund requirements for Task Group 10.3 - DevePapment and techniques %or post-weld inspectisn (costs in 1QQQ dollars) Fiscal 1978

lLO.3.3. 10.3.2

10.3.3

Interpretation records

af customar~y

weld

year

1980

1981

1982

198%

1984

1985

16)

15 20 25 60

21 310 35 86

15 20 25 60

28 25 25 70

BQ 28 20 5Q

10 2Q 28 58

15 15 30

20 20

15 15 38 100

welder

Adaptation methods 10.3.2.1 10.3.2.2 10.%.2.%

Liquid penetsant exatination Radiographic examinatfon Ultrasonic examination

Subtotal

10.3.2

inspection 10 5 5 20

Development of advanced metbods far weld inspectlan 10.3.3.1 Eddy current examination 10.3.3.2 Acoustic emission techniques Subtotal

Tlstal

of automatic

1979

af equipment

lOL$).%.%

operating funds fsa Task GroupIO.%

188

40 141

1986

Table 11.6.3.2.

Capitall equipment fund requirements for Task Group IQ.3 - Development of equipment and techniques far post-weld inspection (costs in 1QQQdollars) Pis cd 1978

1979

RadiographPc examhaticsm

10.3.2.3 Ultrasa~c examination

10.3.2.2

10.3.3.1

Eddy current

10.3.3.2

Acoustic

Total

capital

examination

emissian

techniques

equipment funds for Task Group PO.3

1980

year

1981

5 10

10 20

5 15

1982

1983

1984

11-33

11.6.5

Task 10.3.1

Interpretation of automatic w e l d e r records

It appears possible to interpret the data that is recorded d u r i n g the remote automatic welding of pipe in o r d e r to determine the likelihood of a flaw in each weld pass. It i s known that excessive are voltage and low current will cause lack of weld penetration; low arc voltage and high current, or low wire feed and high weld current will cause welt-through; and irregular carriage and weld speeds w i l l result in uneven bead depth and contour. Work in t h i s task will be dfrected to determining the extent to which data recorded during remote welding can be interpreted amd relied upon for determining the likelihood and location of a weld defect. The feasibility of incorporating t h i s type of weld inspection technique in codes covering remote-pipe welding will be determined, and further work w i l l be carried out if warranted. 11'6.6 ...

Task l0.3.2

Adaptation of customary methods of nondestructive examination of welds

Maintenamee and repair of MSBR components by %emote welding will require techniques for nondestructive examination to ensure the integrity of welds. It is likely that the inspection techniques w i l l have to be suitable for use at te~~~pe~atures in the range of 500 to 7CBO"F and in the presence of gama radiation levels as high as ~ h r .~f necessary, i t is probable that the temperature at t h e point of weld inspection could be lowered to 260 to 400°F by l o c a l cooling. Work in this task group w i l l be aimed at adapting customary methods of nondestructive examination of welds to use at the conditions outlined above in cases where this is feasib1.e. ll.6.6.l

Subtask 18.3.2.1

Liquid penetrant examination

L i q u i d penetrants contafning v i s i b l e or fluorescent dyes are used routinely

for detesting surface-connected flaws in welds. However, cornonly used materials will not be applicable at the high temperatures anticipated for E B R maintenance. Products currently under development show promise for use at temperatures as high as 600 to 980°P; however, little data is available on the sensitivity of such products to surface connected flaws. .:&

&..

... .... :<.a

... ..... ...-.......

Work in this subtask will. be aimed at surveying e o m e r c i a l l y available penetrant examination materials t h a t have potential for high temperature application, and for determining the sensitivity and suitability of t h e products f o r MSBR maintenance applications.

11-34

Subtask 18.3.2.2

ll.6.6.2

Radiographis examination

Work in t h i s subtask w i l l be directed to evaluating the feasibility of easing neutron radiography techniques f o r remote inspect.ion of welds in MSBR system, and to preparing a plan f o r effecting the required development work necessary f o r use of this technique if this is justified.

Ultrasonic examination methods have been u s e d i n c r e a s i n g l y d u r i n g recent

years sop w e l a i n s p g @ t i o n because of t h e a;taiiity of t h i s technique to d e t e c t discontinuities such as cracks and lack of fusion. The mechanical csnvenignace of U . % $ P ~ S C X I ~probes C and their minimal sensitivity to high levels of radkation have l e d to t h e i r use in a number of reactor and h o t - c e l l applications. While welds have been examined s u c c e s s f u l l y with a number of materials, difficulty is encountered in the a p p l i c a t i o n of ultrasonic techniques to nickei-b%se alloys ana s t a i n ~ e s ssteels because of variable attenuation o f sound and the presence of graPn boundary reflections. Additional work is also needed on the development of improved methods f o r c o u p l i n g ultrasound from the transducer i n t o the weldment e

Work in t h i s s u b t a s k w i l l b e directed toward determining the feasibility of and p ~ t e ~ h t i afor l using ultrasonic techniques f o r remote inspection of w e l d s in mBR system, and toward developin p l a n s f o r work required for me of this technique if t h i s appears to be justified.

w..

11-35

ll.6.7.E

Subtask 10.3.3.1

Eddy current e x a d n a t i o n

Methods based on electromagnetic induction of eddy currents have been utilized f o r detecting f l a w s , measuring materials properties, and d e t e r mining the space between adjacent components Application of this technique to the inspection of welds has been quite limited because spurious signals result from variations in coil-to-specimen spacing such as might r e s u l t from roughness of a weld bead. Recent advances in eddy current theory and modeling as well as instrumentation suggest that eddy current examination may Rave potential for remote inspection of welds and determination of pipe j o i n t spacing prior to tack welding. The extent to which eddy currents penetrate a metal is limited; however, it is possible t h a t eddy current techniques could be developed sufficiently f o r consideration as a replacement for liquid penetrant examination techniques. $

Work i n this s u b t a s k will be aimed toward determining the feasibility of eddy current examination techniques f o r remote m h t e n a n c e h s p e c t i o n sf welds in MSBR systems, and toward defining the development work required for application of eddy current techniques if t h i s a p p e a r s

justified. 11.6.9.2

Subtask 10.3.3.2

Acoustic emission techniques

The previously discussed nondestructive examination techniques are used to determine the as-fabricated condition of a weld after the welding operation has been completed. Each is an active technique in that matter or energy is applied to the weld in order to determine its condition. The acoustic emission technique is a passive method in which detectors are w e d f ~ monitoring r t h e sonic energy released within the weld as it is compiet&a produced by actions suck as crack formation or p r o p a g a t i o n . Recent data i n d i c a t e t h a t a c o u s t i c emission techniques have promise for detection of flaws durimg remote welding operations. The transducer materials r e q u i r e d for this teckamique would likely withstand short tern exposure to h i g h temperature and gama radiation, and coupling of the transducers to the weldment would be simpler since the transducer would not be required to traverse the weld area. If acoustic emission s i g n a l s were observed, supplementary examinations using other weld inspection techmiques would be necessary for determining the location of a f l a w .

11-36

rnFErnNCES FOR SECTION 11 E.

%a. Maubenreich, W. Blumberg, and M. Richardson, P B M ~ i ~ t e ~ofi i n ~ ~ the MoHten-Salt Reactor Experiment," hbF%S Winter meeting, Washington, D.C., November 1970 (Complete paper available from a u t h o r s ) .

I?.

5. 6.

8. 9.

10.

R. MeClunag, Bemete Inspection of Welded Joints9 om-m-3561 (Septeder 197l)

12.

12.1

INSTRUMENTATION AND CONTROLS DEVELOPMENT

INTRODUCTION

A significant effort in the development of MSW's will b e devoted to the study of methods f o r controlling the reactor systems during startup, part load, full load, and under upset conditions to allow proper assessment

of the operational and safety implications of various control approaches. While it appears that instrumentation and control systems for MSR's are relatively straightforward, a number of features inherent in this reactor type dictate further development of the technology associated with control methods and systems.

12.1.1

Objective

'Phe general objective of this activity is the development of techndogy necessary for the design of instrumentation and control system required f o r the s a f e and efficient operation of molten-salt reactors. Specifically, the objectives include (1) the development of computer programs required f o r transient representation of MSR systems operating under various control modes, (2) the analysis of control systems having promise f o r molten-salt reactors, ( 3 ) the characterization of power9 pressure, and temperature transients and levels in MSR systems under normal and upset conditions for the more promising control methods, and ( 4 ) the identification and development of instrumentation requfrecl f o r c o n t r ~ l of MSR's.

12.1.2 ...

.... ..,. .a . .

... :,..... ..

% .; r

.... .... .... . a

Scope

The scope of this activity will be restricted initially to demonstrating that satisfactory control methods can be devised for the various operational modes necessary f o r molten-salt reactors, and the identification and development of instrumentation required for utilization of control methods having the greatest potential. The work will be concentrated primarily on the requirements f o r a 10BB-PIW(e) i%BR in o r d e r to identify technology areas requiring further development and demonstration before and during operation of molten-salt test and demonstration reactors. Studies will be carried out as necessary for characterizing transients which m y occur during normal and accident conditions with the preferred control method^ in order that these conditions can be considered properly during t h e development of components and materials for the various reactor system a

*....

A s the designs progress for molten-salt test and demonstration reactors, more detailed attention will be given to the control requirements for these reactors.

.. . ... i.. _Y

._..;.;.;\

12-1 ... .:...., .=

12-2

1% 1 . 2 1 Task Group 1%. 1 e

Control analyses

The work i n t h i s t a s k group will b e d i r e c t e d toward developing computer r e p r e s e n t a t i o n s u f MSR plant: o p e r a t i o n under a v a r i e t y of c o n d i t i o n s , developing and a n a l y z i n g varisus control methods, d e t e r m i n i n g t h e requirements f o r meaningful f l u x measurements i n S R ' s , c h a r a c t e r i z i n g p r e s s u r e and temperature t ~ a n s i e n t sf o r v a r i o u s o p e r a t i n g modes, speci f y i n g t h e requirements sf special i n s t r u m e n f a t f o n and c o n t m l d e v i s e s such as a s a l t t h r o t t l i n g valve f a r p a r t i a l l y b y p a s s i n g t h e secondary soslanr around the primary h e a t exchangers f u r t h e r e v a l u a t i n g t h e need f o r f a s t scram c a p a b i l i t y i n MSR systems, and d e t e r m i n i n g t h e need f o r i n s t r u m e n t a t i o n i n MSBR p r a c e s a i n g s y s t e m s . The modeling and a n a l y s i s ~f p l a n t t r a n s i e n t b e h a v i o r w i l l b e c o o r d i n a t e d w i t h s i m i l a r e f f o r t s associated w i t h s a f e t y s t u d i e s ( s e e S e c t i o n 7 ) t o e n s u r e optimum u t i l i z a t i o n of a n a l y t i c a l and computing c a p a b i l i t i e s #

The work i n t h i s t a s k group will b e d i r e c t e d toward developing high t e m p e r a t u r e f l u x s e n s o r s sapable of operation at IB3OO"P and h i g h e r w i t h the high r e l i a b i l i t y r e q u i r e d f o r P ~ ~ C ~ e Oo nKt r o l systems ; t h e development of improved i n s t r u m e n t a t i o n a l l o w i n g d i r e c t measurements of pressures f l a w , and l e v e l i n m o l t e n - s a l t s y s t e m ; and t h e assessment of t h e availa b i l i t y of i n s t r u m e n t a t i o n f o r MSR's and the need f o r a d d i t i o n a l development and a d a p t i o n .

12.2.1

Schedule and key program m i l e s t o n e s

The s c h e d u l e %OX- work on i n s t r u m e n t a t i o n and c ~ n t t r o l sdevelopment is s h o r n i n T a b l e 12.2.H.l, The key program m i l e s t o n e s f o r t h i s a c t i v i t y are l i s t e d i n Table 12.2.1.2 and occur a t t h e times shown i n Table

12.2.1.1. 12.2.2 k<...

The o p e r a t i n g fund requirements f u r this a c t i v i t y a r e shown i n Table C a p i t a l equipment funds w i l l b e r e q u i r e d d u r i n g ET E980 in. t h e 12.2.2. amount of $170,000 f o r d e s i g n and s o n s t m e t i o n of t h e I n s t r u m e n t a t i o n Test Facility.

12-3

...

2 ,

The c o n t r o l system requirements of an MSBR a r e b a s i c a l l y t h e same as t h o s e of o t h e r power r e a c t o r s ; k ~ ~ e ~ ae number r , of f e a t u r e s which a r e p e c u l i a r t o t h i s r e a c t o r concept a f f e c t the i n s t r m e n t a t i o n and c o n t r o l systems e

In t h e r e f e r e n c e MSBR d e s i g n , t h e e n t i r e primary s a l t system i s l o c a t e d i n a primary containment t h a t i s maintained at about 1800'F. This

....

,&!&

arrangement makes i t unnecessary t o i n s u l a t e t h e p i p e s and vessels and removes f r o m t h e r e a c t o r c e l l a m u l t i t u d e of e l e c t r i c a l c a b l e s , themocouples, d i s c o n n e c t s , and containment p e n e t r a t i o n s t h a t would b e r e q u i r e d f o r h e a t e r s l o c a t e d d i r e c t l y on t h e p i p e s and v e s s e l s . Some c ~ n n e c t ~ r s and s i g n a l t r a n s m i s s i o n Pines must e i t h e r b e designed t o o p e r a t e p r o p e r l y i n such a n environment o r must b e l o c a t e d i n p e n e t r a t i o n s t h a t are cooled reliably a

The high f r e e z i n g p o i n t s o f the MSBR f u e l and c o o l a n t s a l t s impose r a t h e r s t r i n g e n t c o n t r o l and p r ~ t ~ ~ t system i o n r e q u i r e m e n t s . Care must b e exe r c i s e d t o prevent f r e e z i n g of t h e s a l t i n a u x i l i a r y l i n e s , as w e l l as i n main s a l t l i n e s and h e a t exchangers.1 r he f i l l i n g and s t a r t u p proced u r e s , although. s i m p l i f i e d by t h e oven concept, w i l l be somewhat complex, as w i l l b e t h e procedure f o r a d m i t t i n g feedwater i n t o the steam-generator system. 1 ~ e l i a b ~i nes t r u m e n t a t i o n must b e provided f o r determining t h e c o n d i t i o n of t h e s a l t when i t i s o u t s i d e t h e r e a c t o r v e s s e l as well as within * The e f f e c t s of fuel c i r c d a t f o n on t h e e f f e c t i v e delayed n e u t r o n f r a c t i o n must b e c o n s i d e r e d in d e s i g n i n g for t r a n s i e n t c o n d i t i o n s i n v o l v i n g p r i mary system f l o w changes. These e f f e c t s a r e w e l l understood, and exper i e n c e i n t h e d e s i g n and o p e r a t i o n of c i r c u l a t i n g f u e l r e a c t o r s gives c o n f i d e n c e t h a t t h i s f e a t u r e w i l l n o t Cause any p a r t i c u l a r problem. F i s s i o n p r o d u c t s i n t h e primary c i r c u l a t i n g l o o p present t h e u s u a l problems sf handling radioactive f l u i d s . The p r e s e n c e of these h i g h l y r a d i o a c t i v e loops a l s o has a p o t e n t i a l €01- i n c r e a s i n g background s i g n a l s i n n u c l e a r i n s t r u m e n t a t i o n . Replacement o f instrument s e n s o r s and i n t e r c o n n e c t i n g s i g n a l l i n e s w i l l i n some cases r e q u i r e remote mainten2nce techniques. The ~ e f e r e n c eE3BW i s designed t o have a c ~ r ed i f f e r e n t i a l temperature of 258°F. A s i n o t h e r r e a c t o r s o p e r a t i n g w i t h a large AT, means must be provided to l i m i t thermal stresses d u r i n g abnormal o p e r a t i o n a l events.

.... ..:.=

.... ..... .x.

.... ..... .:.x.:*

The MSBR does n o t r e q u i r e t h a t a l a r g e amount s f e x c e s s r e a c t i v i t y b e a v a i l a b l e . The a b i l i t y t o a d j u s t f u e l c o n c e n t r a t i o n d u r i n g o p e r a t i o n and t h e r e d u c t i o n of '3%e p o i s o n i n g by gas s t r i p p i n g reduce two of t h e l a r g e s t r e a c t i v i t y requirements of s t h e r t y p e s of p l 2 n t s . T o t a l c o n t r o l r e a c t i v i t y r e q u i r e d for o p e r a t i o n w i l l probably b e on t h e order of E% Gk/k. This s m d - 1 amount sf excess r e a c t i v i t y g r e a t l y reduces t h e potent i a l f o r l a r g e r e a c t i v i t y e x c u r s i o n s thus e a s i n g requirements on s a f e t y

Table 12.2.1.1.

Schedule and major milestane designations far instrumcntatian

and contraPs develspment --

-7 1

--I.101 Control analyses 11.2 Instrumentation

1977

-l---development

/ 1

---qL.

Table X2.2.2.

Operating

fund requirements for instrumentation (costs in 1QOOdollars)

1977 PI.1

Control

analyses

11.2

Instrumentation

Total

operating

funds

and controls

Fiscal

year

development

197%

1979

1980

1981

1982

1983

1984

1985

141

210

280

295

250

300

350

370

545

556

6QO

6QQ

development 4%

141

270

1986

12-5

Table 12.2.1.2. Key m i l e s t o n e s f o r i n s t r u m e n t a t i o n and c o n t r o l s development

Miles t o n e

Description

Complete computer r e p r e s e n t a t i o n of primary, secondary, and steam c i r c u i t s o f MSBR. Complete assessment f o r need of f a s t scram c a p a b i l i t y of PISBR.

Complete development

Complete s p e c i f i c a t i o n s f o r s a l t t h r o t t l i n g v a l v e s f o r MSBR c o n t r o l .

C o ~ p l e t em o d i f i c a t i o n of computer r e p r e s e n t a t i o n of steam system f o r MSBW t o r e f l e c t r e s u l t s from steam generator t u b e test s t a n d .

Complete d e t e r m i n a t i o n of ~ e t h ~f odr r e a c t i v i t y a c c o u n t i n g and i n v e n t o r y c o n t r o l i n a n MSBR. Complete s t u d i e s on i n f o r m a t i o n a c h i e v a b l e by f l u x measurement a n a l y s e s in an

S€

i n t e r i m c o n t r o l methods f o r MSBR.

MSBR.

Complete asses~merttof MSBR p r o c e s s i n g p l a n t i n s t r m e n t a t i o n needs and a v a i l a b i l i t y . Complete development and assessment of c o n t r o l methods f o r MSBR. Complete development p l a n f o r improved p r e s s u r e , f l o w , and level devices

Complete development plan f o r high temperature f l u x

sensors. .... .... . l.%c

Complete assessment o f a v a i l a b i l i t y of i n s t r u m e n t a t i o n f o r MSBR p r o c e s s i n g p l a n t and development p l a n for p r o v i d i n g insfrunaentatfon n o t a v a i l a b l e .

complete development ana t e s t i n g of p r o t o t y p i c devices for improved p r e s s u r e , f l o w , amd l e v e l measurements. ...

......,

i.!d ,.!%

.... 2. ...

.... .x.:.;

... ..... ......,

i I

Complete development and t e s t i n g of p r o t o t y p i c highte€llp@ratUpe flux SC?RSQrS.

12-6

rods. The a b i l i t y t o d r a i n t h e f u e l away from t h e moderator into a n o n c r i t i c a l c o n f f g u r a t i s n i s a very i m p o r t a n t f e a t u r e of t h e molten s a l t r e a c t o r concept. The i n t e n t i s n o t t o u s e t h e f u e l drain f o r f a s t s h u t skom b u t to assure long-term shutd0wI.E m r g i n under unusUa,a circumstances > hence f a s t - a c t i n g d r a i n v a l v e s are n o t r e q u i r e d .

12.3.1

Requirements and c u r r e n t concepts

12.3.1.1

Systems f o r n o m a l o p e r a t i o n

Xormal o p e r a t i o n of an MSBW i n c l u d e s aH% phases of s t a r t u p from c o l d o r hot standby c o n d i t i o n s , p r o d u c t i o n of e l e c t r i c power a t demand l o a d s between 20 and 100% of d e s i g n c a p a b i l i t y , and scheduled shutdown. The c o n t r o 1 s y s t e m must allow f o r t h e d i f f e r e n t r e q u i r e m e n t s f o r t h e v a r i o u s o p e r a t i n g modes and e s t a b l i s h and m a i n t a i n s a f e and a p p r o p r i a t e o p e r a t i n g c o n d i t i o n s . The s y s t e m m u s t c o o r d i n a t e t h e o p e r a t i o n of t h e r e a c t o r , t h e primary- and s e c o n d a r y - s a l t Hoops, t h e s t e m g e n e r a t o r s , and system a u x i l i a r i e s . In g e n e r a l , l o a d demand i s t h e primary s i g n a l t o which t h e c o n t r o l subsystems must respond. M Q W ~ V ~w~h,i l e matching t h e power g e n e r a t i o n w i t h t h e load, t h e c o n t r o l system must a l s o m a i n t a i n system t e m p e r a t u r e s and t h e i r rates of c h m g e w i t h i n a c c e p t a b l e l i m i t s . Specific areas of concern are t h e t e m p e r a t u r e i n t h e s a l t lo(sps, and t h e s a l t t e m p e r a t u r e s which m u s t b e maintained w e l l above the f r e e z i n g p o i n t throughout t h e c i r c u l a t i n g systems (with t h e p o s s i b l e e x c e p t i o n of SQme areas i n t h e steam generator). The p r e s e n t concept i s t o c o n t r o l t h e n u c l e a r power l e v e l by g r a p h i t e r o d s which are used in an a u t o m a t i c c o n t r o l loop t o m a i n t a i n r e a c t o r t e m p e r a t u r e a t a s e t p o i n t programmed a c c o r d i n g t o t h e needs o f t h e steam system. T h i s arrangement is a v a r i a t i o n of a scheme s u c c e s s f u l l y dernons t r a t e d on t h e NSWZ, where the t e m p e r a t u r e s e t p o i n t w a s d e f i n e d by the o p e r a t o r . I n such a c o n t r o l system, t h e r e a c t o r power i s determined by the l o a d , w i t h a t e m p e r a t u r e b a s e l i n e i n d e p e n d e n t l y determined to p r o v i d e s t e m a t t h e desired temperature. Maneuvering from one power l e v e l t o a n o t h e r r e q u i r e s c o n t r o l of steam t e m p e r a t u r e d u r i n g t h e t r a n s i e n t . The c u r r e n t concept i n v o l v e s autom t i c SoIltPol O f SeConday S a l t f l o w rat@ through t h e S t e m generator i n o r d e r to t a k e advantage of t h e t h e r m a l c a p a c i t y o f t h e s a l t while t h e r e a c t o r power l e v e l i s b e i n g r e a d j u s t e d t o the new r e q u i r e m e n t . I n a ~ l k l l t i l o o pp l a n t , such as t h e r e f e r e n c e E B R , t h e c o n t r o l system must a d e q u a t e l y respond t o l o o p i n t e r a c t i o n s The most s a t i s f a c t o r y approach a p p e a r s t o b e one i n which each loop is c o n t r o l l e d as a mi^ to P H O ~ U C a~ s p e c i f i e d amount of s t e a m UIICICX weii-defined c o n d i t i o n s , ~ : t h t h e b a l a n c i n g of the l o o p s b e i n g c o n t r o l l e d by a master p r o g r m e r perhaps a d i g i t a l c ~ m p u t e r- t h a t i s r e s p o n s i v e t o t h e needs of t h e power g r i d . T h i s p r o g r a m e r would a d j u s t s e t p o i n t s on a p p r o p r i a t e c l o s e a - l o ~ p e Q n t r Q l l @ r SaSSOCiated With the COQk%nt%OOPS e

12-7

12.3.1.2

Emergency systems

I n a d d i t i o n t o p r o v i d i n g normal c o n t r o l f u n c t i o n s t h e i n s t r u m e n t a t i o n and c o n t r o l system must p r o v i d e p r o t e c t i o n a g a i n s t a v a r i e t y of anomalous o r a c c i d e n t c o n d i t i o n s . Although t h e e n t i r e c o n t r o l s y s t e m shobtld cunt r i b u t e t o s a f e and o r d e r l y o p e r a t i o n s , there w i l l b e a s y s t e m d e d i c a t e d e n t i r e l y t o p r o t e c t i o n 0 % personnel. and t o t h e p r e v e n t i o n o f m a j o r equipment damage. T h i s l a t t e r s y s t e m , t h e p l a n t p r o t e c t i o n s y s t e m ( P P S ) , i n c l u d e s m o n i t o r i n g i n s t r u m e n t a t i o n t o d e t e c t off-noma1 c o ~ ~ d i t i o n s , l o g i c subsystems t o make d e c i s i o n s and i n i t i a t e c o r r e c t i v e a c t i o n s , a c t u a t o r s t o e f f e c t system c o n t r o l a c t i o n s , and p o s t - a c c i d e n t m o n i t o r i n g s y s terns

The p l a n t p r o t e c t i o n system must b e c a p a b l e of s h u t t i n g down t h e p l a n t when n e c e s s a r y and c a r r y i n g o u t o t h e r p r o t e c t i v e f u n c t i o n s , s u c k as e n s u r i n g t h a t systems are i n o r d e r € o r c o n t a i n i n g t h e r a d i o a c t i v i t y i n t h e e v e n t of a m a j o r a c c i d e n t and t h e removal o f a f t e r h e a t f o l l o w i n g a n emergency shutdown where n o r m a l c o o l i n g i s i m p a i r e d :.m

Whereas t h e c o n t r o l r o d s w i l l b e g r a p h i t e p a r t i a l l y i n s e r t e d i n t o the c o r e 8 0 that p o s i t i v e and n e g a t i v e r e a c t i v i t y changes can b e made, t h e s a f e t y r o d s w i l l b e n e u t r o n - a b s o r b i n g p o i s o n r o d s of c o n s i d e r a b l y more r e a c t i v i t y w o r t h . Because of t h e i r e f f e c t on n e u t r o n economy and b r e e d i n g , t h e s a f e t y r o d s would n o r m a l l y b e withdrawn o u t of t h e a c t i v e Core r e g i o n . However, c o n t i r ~ u o u sa d j u s t m e n t Of t h e i r p o s i t i o n s h o u l d b e p o s s i b l e t o f a c i l i t a t e X - ~ ~ Q V ~ I from -Y uff-normal c o n d i t i o n s

E% i s n o t c l e a r a t t h i s t i m e t h a t a f a s t "scram" c a p a b i l i t y will b e r e q u i r e d . The prompt n e g a t i v e t e m p e r a t u r e c o e f f i c i e n t o f t h e f u e l p l u s t h e s i g n i f i c a n t t h e r m a l c a p a c i t y of t h e s a l t and g r a p h i t e are f a c t o r s which make t h e p l a n t less s e n s i t i v e t o r e a c t i v i t y e x c u r s i o n s . However, d e t a i l e d a n a l y s e s of a p a r t i c u l a r p l a n t d e s i g n w i l l be n e c e s s a r y t o e s t a b l i s h the p r e c i s e r e q u i r e m e n t s of t h e PPS. 112 3 . 1 3

Instrumentation

The o p e r a t i o n a l c o n t r o E s y s t e m s and t h e p l a n t p r o t e c t i o n s y s t e m w i l l .:&

require extensive instrumentation t o provide input t o the automatic decision-making p r o c e s s of c o n t r o l . Measurements of n e u t r o n f l u x l e v e l s , as w e l l as of t h e n o n n u c l e a r v a r i a b l e s such a s f l o w rates, p r e s s u r e s , t e m p e r a t u r e s , e t c . , w i l l b e v i t a l t o e f f e c t i v e c o n t r o l of t h e p l a n t . Some i n s t r u m e n t s e n s o r s and s i g n a l t r a m s m i s s i o n P i n e s , a n d p o s s i b l y some containment p e n e t r a t i o n s w i l l be r e q u i r e d t o o p e r a t e r e l i a b l y i n h o s t i l e e n v i r o n m e n t s of hFgh t@mperature, h i g h r a d i a t i o n l e v e l s , o r b o t h . The high r e s i d u a l r a d i o a c t i v i t y i n the r e a c t o r c e l l w i l l make d i r e c t m a i n t e nance i m p o s s i b l e i n many l s c a t i o n s and a c c e s s i b i l i t y of i n s t r u m e n t components f o r ~ e m ~ td ies c o n n e c t and r e p l a c e m e n t w i l l b e n e c e s s a r y .

12-8 I n g e n e r a l , c o n v e n t i o n a l e l e c t r o n i c o r pneumatic s i g n a l c o n d i t i o n i n g However, the s i z e and comequipment can m e e t t h e needs sf the %BW. p l e x i t y o f t h e p l a n t will make i t h i g h l y d e s i r a b l e t o u s e d i g i t a l computer techniques f o r m u l t i p l e x i n g , d a t a s t o r a g e and r e t r i e v a l , c a l c u l a t i o n , and o t h e r f u n c t i o n s . Optimization of t h e p l a n t o u t p u t w i l l r e q u i r e deVe%ClpITMXlt Sf SSphkStiCated C o n t r o l schemes. a high d e g r e e of automation and s u p e r v i s o r y c o n t r o l w i l l be n e c e s s a r y i n the MSBR, a s i n any l a r g e m u l t i l o u p p l a n t , because of t h e l a r g e n u d e r of i n t e r a c t i n g p%OCeS%eS. U s e Sf autoE3tiC Control lS0p.S f o r iB large IfuRlbel- Of §yStefn control f ~ n c t i ~ niss commonplace; however t h e i n t e g r a t i o n of t h e s e i n t o e f f e c t i v e system control. i s o f t e n left to t h e o p e r a t o r . S i g n i f i c a n t improvements i n o p e r a t i o n can b e achieved if o v e r a l l system c o n t r o l i s h i g h l y a ~ t o m a t e du s i n g ~ e l l - e s t a b l i s h e d t e c h n i q u e s .

12.3.2

Experience w i t h t h e MSWE and o t h e r f a c i l i t i e s

A l a r g e number of o u t - o f - p i l e and i n - p i l e l o o p s and o t h e r f a c i l i t i e s have been o p e r a t e d w i t h molten s a l t a t OWN, over t h e p a s t 20 y e a r s which have had i n s t r u m e n t a t i o n and c o n t r o l s y s t e m of v a r y i n g d e g r e e s of complexity. In a d d i t i o n , 0 and o t h e r s have o p e r a t e d h i g h - t e m p e ~ a t u r e systems c o n t a i n i n g t a ~ l t e nmetals o r gases, and a number of r e a c t o r s of t h e s e types have been o p e r a t e d i n t h e U.S. and abroad. Although t h e s e have provided e x p e r i e n c e i n i n s t r u m e n t a t i o n t h a t i s a p p l f c a b l e t o MSR's, t h e mst d i r e c t and u s e f u l i n f o r m a t i o n has corne from the o p e r a t i o n of t h e MSRE.2

Successfu1 o p e r a t i o n of hundreds sf thermocouples a t t a c h e d t o t h e s a l t system walls i n the MSRE g i v e s confidence t h a t r e l i a b l e t e m p e r a t u r e measurements can b e made a t t h e e l e v a t e d temperatures sf m o l t e n - s a l t r e a c t o r systems. Although t h e r e w a s considerable scatter i n t h e r e a d i n g s of the c o u p l e s under d i f f e r e n t h e a t e r s when the s a l t w a s a c t u a l l y i s a $heKIEd, teChsliqUeS of biasing t h e otltpkits were Used to p r o v i d e thQrOUghly The importance of c a r e f u l s e l e c t i o n and c a l i a c c e p t a b l e measurements. b r a t i o n , d e t a i l s of f a b r f e a t i o n and i n s t a l l a t i o n , and s t r i c t q u a l i t y C O I I ~ K U ~w a s e v i d e n t , i n t h a t o n l y 1 2 of t h e 336 t h ~ ~ ~ ~ o ~ ~ f ati l epd l e s drarimg f i v e y e a r s of operation. P r e s s u r e and d i f f e r e n t i a l p r e s s u r e measurements i n t h e c Q o l a n t s a l t systems were m d e using B a K - f i l l e d t r a n s m i t t e r s . No d i r e c t measurement where gas pressure of s a l t p r e s s u r e w a s made i n t h e p % - f m ~system, y measurements were used t o i n f e r salt-system p r e s s u r e . Direct measurements are d e s i r a b l e i n a n MSBW, and a d d i t i o n a l development may b e %-equiPedf O K SUCh appPiCatiOE3. The measurement of s a l t flow rate i n t h e secondary system w a s made by means of a v e n t u r i and a NaK-filled d i f f e r e n t i a l p r e s s u r e t r a n s m i t t e r . No d i r e c t measurement was made sf flow i n t h e primary system. Inasmuch as the r e a c t o r w a s o p e r a t e d w i t h c o n s t a n t p r i m a r y - s a l t f l a w rate, no p a r t i ~ d aproblem ~ e x i s t e d i n n o m a % o p e r a t i o n . A s p a r t sf t h e p l a n t protection SySt@TIl iflstlXEtEntation, pUlRp lIIotol" CUKrent Was measUK€?d.

i.z.,

12-53

Though n o t a p r e c i s e i n d i c a t i o n of flow, t h i s measurement plus pump speed gave adequate a s s u r a n c e of flow. That is, t h e pump motor c u r r e n t w o d d b e less than normal even though t h e speed w a s normal i f for some r e a s o n t h e s a l t f l o w w a s reduced. Direct measurement of t h e flow i n t h e primary system would be d e s i r a b l e f o r a power r e a c t o r $ e s p e c i a l l y i f variable %low is Level measurements were made with s i n g l e - p o i n t p r o b e s as w e l l as b u b b l e r s and f l o a t l e v e l s y s t e m . These o p e r a t e d v e r y w e l l over the l i f e of the p l a n t , b u t each has l i m i t a t i o n s which m y n e c e s s i t a t e a d d i t i o n a l develspment f o r a p p l i c a t i o n t o %BR service. Containment penetration cable seals were d i f f i c u l t and c o s t l y to i n s t a l l , andl their performnce w a s m r g i n a l . 2 ~n t h e f u r n a c e concept of t h e MSBR it w i l l be d e s i r a b l e t o l o c a t e t h e seals i n t h e r m a l l y i n s u l a t e d areas, I n a d d i t i o n t o v a l u a b l e e x p e r i e n c e i n i n s t r u m e n t i n g molten-salt systemsE t h e MSRE gave a n ~ p p o r t ~ n i t tyo v e r i f y methods of a n a l y s i s of t h e dynamics of c i r c u l a t i n g - f u e l r e a c t o r s he o p e r a t i o n with 2 3 3~ w a s p a r t i c u l a r l y i n t e r e s t i n g because of t h e u n u s u a l l y small e f f e c t i v e delayed n e u t r o n ~ n a l y s e sand tests wade p r i o r t o l o a d i n g 2 3 3 ~ f r a c t i o n ( ~ , f f = O.OOD) i n t o t h e MSRE gave confidence t h a t t h e system would b e web1 behaved w i t h r e g a r d t o s t a b i l i t y and c o n t r o l l a b i l i t y e 4 s R e s u l t s o f tests performed a f t e r l o a d i n g w e r e i n good agreement with t h e p r e d i c t i o n s . 6 e

The MSRE rod c o n t r o l l e r w a s designed t o wake t h e r e a c t o r o p e r a t e i n a load-following, o r r~c$ss-slave-ts-load, mode in t h e power r a n g e En this mde t h e o p e r a t o r s e l e c t e d t h e d e s i r e d temperature of t h e s a l t l e a v i n g t h e r e a c t o r c o r e , and t h e s t e a d y - s t a t e r e a c t o r power w a s d e t e r mined by t h e r a t e at which h e a t was r e j e c t e d by t h e a i r - c o o l e d h e a t exchanger i n t h e secondary s a l t system. From an e x p e r i m e n t a l viewpoint this allowed e a s y automatic c o n t r o l s f t e m p e r a t u r e and power level, w i t h p r a c t i c a l l y no i n t e r a c t i o n between them. For a power r e a c t o r t h i s scheme h a s t h e p o t e n t i a l f o r c o n t r o l l i n g stem temperature independently of power level. The control system used on t h e MSRE m e t the s p e c i f i c requirements of that r e a c t o r and encourages t h e u s e of such a c o n t r o l l e r as p a r t of t h e o v e r a l l MSBR p l a n t c o n t r o l system.

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The d i g i t a l data collecting and computing system f o r t h e MSRE w a s used e x t e n s i v e l y w i t h e x e e l l e n t results. The o v e r a l l y a v a i l a b i l i t y a f t e r a n i n i t i a l debugging p e r i o d was over 9 5 X e 7 The system proved i n v a l u a b l e f o r t h e t i m e l y and economic c o l l e c t i n g , l o g g i n g , and a n a l y z i n g of e x p e r i mental data g e n e r a t e d by t h e MSRE. I n a d d i t i o n , i t w a s used t o p r o v i d e o p e r a t o r guidance through t h e s t a n d a r d p r i n t o u t of s i g n a l s i n t h e form of r o u t i n e periodic logs, alarm signal p r i n t o ~ t ,r o u t i n e c a l c u l a t i o n s ed such as h e a t b a l a n c e and r e a c t i v i t y b a l a n c e , and o p e b - a t ~ r - d e ~ ~ a n dfunctions and c a l c u l a t i o n s . E t was used e x t e n s i v e l y f o r t h e e o n t r o l and i n s t r u m e n t a t i o n of reactor d y a m i e t e s t s , such as frequency r e s p o n s e and t e m p e r a t u r e response expe~iments 8 f o r r e t r i e v i n g ~ R C p I r o c e s s i n g data p r e v i o u s l y s t o r e d on magnetic tapes fob" analysis, and t o provide i d o r mation r e l a t i v e to t h e t i m e , c a u s e , and e f f e c t of abnormal o p e r a t i n g

12-10

events. Programs w e r e developed t o a i d i n c a l i b r a t i o n of a n a l o g systems and i n d i a g n o s i s of t r o u b l e s . A program w a s developed far a f a s t Fourier transform which w a s p r o g r a m e d t o run on l i n e i n background t h e and which w a s used r o u t i n e l y f o r o n - l i n e a n a l y s i s of n e u t r o n f l u c t u a t i o n d a t a . By use of t h i s program i t w a s p o s s i b l e t o monitor t h e bubble fraction i n t h e f u e l salt.9 9 Q The o v e r a l l e x p e r i e n c e w i t h t h e computer system w a s ewce%%entand demonstrated t h e tr@D"ldOuS Valebe Of such El system i n a CQl?lpIeX '$laIlt. A comprehensive d a t a c o l l e c t i n g and computing system for an KSBR i s eonsidered t o be indispensable.

The HSRE e x p e r i e n c e i s v a l u a b l e i n d e n a n s t r a t i n g t h a t most of t h e unique i n s t r u m e n t a t i o n and contro1 p r o b l e m a s s o c i a t e d w i t h circulatfng f u e l r e a c t o r s are amenable t o s o l u t i o n w i t h f a m i l i a r t e c h n i q u e s . Those problems which were n o t solved or which w e r e circumvented due t o l i m i t e d t i m e o r funds w i l l b e easier t o resolve f o r MSBR a p p l i c a t i o n s by t h e i n s i g h t gained from MSRE o p e r a t i o n .

12.3.3

S t a t u s of sontroa a n a l y s e s

P r e l i ~ ~ i m rs yt u d i e s of s t a r t u p , standby, and shutdowm p r ~ e e d u r e shave been carried out f o r t h e r e f e r e n c e d e s i E B R , although o n l y t o the p o i n t of determining f e a s i b i l i t y . I n m i n g t h e s e a n a l y s e s , several basis r e s t r a i n t s on o p e r a t i o n of the p l a n t were reeo ized. The f r e e z i n g temperatures of t h e primary and secondary s a l t s are such t h a t the s a l t systems must b e f i l l e d and s a l t c i r c d a t e d isothermally a t 100Q"F b e f o r e power withdrawal can be i n i t i a t e d by d e c r e a s i n g the c o o l a n t - s a l t tempera t u r e . To a v o i d f r e e z i n g of t h e s a l t and to p r e v e n t e x c e s s i v e temperature g r a d i e n t s , the minimum feedwater BP steam temperature to t h e steam g e n e r a t o r s for t h e reference design system must v a r y between 1800°F a t zero l o a d and 760°F i n the 8 t o lQQ% power range. I n a d d i t i o n , t h e afterheat l o a d i n t h e reactor system, which decays slowly, may r e q u i r e t h a t the f e e d w a t e r and heat r e j e c t i o n system remain i n ~ p e r a t i ~ n f o l l o w i n g shutdown of t h e main steam system. Most of the s p e c i a l system and equipment needed t o handle t h e s t a r t u p and shutdown c o n d i t i o n s i n an MSBR s t a t i o n a r e a s s o c i a t e d with t h e steam%he requfreEE!nts iEtpOSe SOme d e p a r t u r e f P O W t h e e ¶ U i V power system. a l e n t s y s t e m used i n c o n v e n t i o n a l f o s s i l - f i r e d s u p e r e r i t i s a l - p ~ e s s P e steam p l a n t s and w i l l r e q u i r e f u r t h e r s t u d y . D f f f e r e n t s t e a m g e n e ~ a t o r d e s i g n s , f o r example r e e n t r a n t or c o n c e n t r i c - t u b e t y p e s , would n o t r e q u i r e and would alter t h e steam p l a n t h e a t i n g t h e feedwater as h o t as 708'F, arrangement. h a u x i l i a r y b o i l e r i s n e c e s s a r y f o r s t a r t u p from t h e c o l d COnditiOn.

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Computer models

The dynamics and c o n t r o l s t u d i e s of MSBR p l a n t s have been c o n c e n t r a t e d about the n o m a 1 o p e r a t i n g power range, and a series of s t u d i e s has been made t o examine t h e s e o p e r a t f n g c h a r a c t e r i s t i c s 9 I The s t u d i e s have been implemented with analog and hybrid computer s i m u l a t i o n s of t h e p l a n t A l l of t h e s i m u l a t i o n s have been p a t t e r n e d a f t e r characteristics. l4 t h e MSBR r e f e r e n c e design,l b u t t h e n a t u r e of the models is such tliat they would have g e n e r a l a p p l f e a b i l i t y . For t h e purpose of these a n a l y s e s t h e MSBR p l a n t c o n s i s t e d of a s i m p l i f i e d graphite-moderated, c i r c u l a t i n g f u e l r e a c t o r , a shell-and-tube h e a t exchanger f o r t r a n s f e r r i n g t h e genera t e d h e a t t o a secondary c o o l a n t s a l t , a shell-and-tube s u p e r c r i t i c a l stem g e n e ~ a t o r ,and several p o s s i b l e c o n t r o l systems.

Due t o t h e v e r y n o n l i n e a r n a t u r e of t h e once-through steam g e n e r a t o r , i t w a s n e c e s s a r y t~ develop a h i g h l y d e t a i l e d model sf t h i s p a r t of t h e system, I n o r d e r t o approximate o v e r a l l p l a n t performance, t h e e a r l i e r models used lumped-parameter , l o g - m e % n - d 8 € € e r e n t i a l - t e m ~ e r a t u r ~analog simulation of t h e stem g e n e r a t o r , a l t h o u g h t h e accuracy w a s known t o b e s e v e r e l y l i m i t e d . A t t h e same t i m e , a hybrid d i g i t a l - a n a l o g model w a s developed and used i n i t i a l l y t o examine t h e s t a b i l i t y of t h e steam g e n e r a t o r . 1 6 The h y b r i d model of t h e steam g e n e r a t o r w a s combined w i t h an analog r e p r e s e n t a t i o n of t h e o t h e r p l a n t components r e s u l t i n g i n an o v e r a l l s i m u l a t i o n i n which c o n s f d e r a b l e conf idence could be p l a c e d e R e p r e s e n t a t i v e t r a n s i e n t r e s p o n s e s u s i n g t h i s model are d e s c r i b e d in Reference 15.

The g e n e r a l v a l i d i t y of t h e a l l - a n a l o g models w a s confirmed, a l t h o u g h , as expected, some disagreement i n absolu%e v a l u e s w a s observed. The t r e n d s i n d i c a t e d i n t h e analog s t u d i e s are c o r r e c t , b u t the magnitude and rates of change of v a r i a b l e s d u r i n g t r a n s i e n t s should be used o n l y as g e n e r a l guides.

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.. i i i,

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The h y b r i d model was used t o s t u d y c o n t r o l schemes and normal plant maneuvering. Some more s e v e r e t r a n s i e n t s were examined t o d e t e m t n e system response t o abnormal s i t u a t i o n s . The s e v e r i t y of t h e t r a n s i e n t s t h a t could be run on t h e h y b r i d s i m u l a t i o n model w a s , however, l i m i t e d by t h e stem g e n e r a t o r model, which used 0.5-second c a l c u l a t i o n a l t i m e s t e p s . Consequently, i t will be n e c e s s a r y t o improve the accuracy w i t h which t h e steam g e n e r a t o r can be r e p r e s e n t e d (probably u s i n g a d i g i t a l computer) i n o r d e r t o s t u d y more severe t r a n s i e n t s and complement t h e plant safety analysis

, ..&

12.3.3.2 < :.,..... ,....

A n a l y s i s of s t e a d y - s t a t e c o n d i t i o n s

....

The f i r s t step i n t h e f o r m u l a t i o n of a c o n t r ~ lsystem t o e n a b l e t h e p l a n t t o ~ n d e r gchanges ~ i n Isad w a s t o determine t h e s t e a d y p a r t - l o a d tempera t u r e and f l o w p r o f i l e s f o r o p e r a t i o n between 20 and 100% s f f u l l l o a d . For i n i t i a l c o n s i d e r a t i o n s it w a s d e s i r a b l e t o f i x predetermine t h e s t e a d y - s t a t e v a l u e s of some v a r i a b l e s f o r part-load o p e r a t i o n . ' E u r b i ~ e

12-12

E m i t a t i o n s r e q u i r e t h a t t h e t u r b i n e t h r o t t l e temperature b e h e l d n e a r l y c o n s t a n t (1000'F f o r t h e cases s t u d i e d ) , and t h e feedwater temperature w a s h e l d constant as w e l l (700'F). The primary s a l t flow r a t e was assumed c o n s t a n t a t d e s i g n p o i n t f o r s t e a d y - s t a t e c o n s i d e r a t i o n s With t h e s e I i m i t a t i o n s imposed, i t w a s foretd t h a t t h e secondary-salt tempera t u r e a t t h e steam g e n e r a t o r o u t l e t c o u l d n o t b e h e l d above t h e s a l t f r e e z i n g p o i n t a t p a r t loads below a b o u t 50%. Thus methods mst be d e ~ e l ~ p ewhich d a l l o w more e f f e c t i v e decoupling of l o a d e f f e c t s on s a l t temperatures. So= p o s s i b i l i t i e s are: ( I ) a l l o w i n g t h e steam temperature t o i n c r e a s e above t h e PQ0B"P d e s i g n p o i n t as t h e l o a d d e c r e a s e s , w i t h subsequent a t t e m p e r a t i o n of t h e steam with i n j e c t e d feedwater; (2) inc r e a s i n g the feedwater temperature above t h e 7OQ'P design p o i n t as t h e l o a d d e c r e a s e s ; (3) reducing the number of steam g e n e r a t o r s 5-19 u s e as l o a d d e c r e a s e s ; and ( 4 ) u s i n g a s a l t t h r o t t l i n g valve t o bypass some of t h e s e c o n d a r y - s a l t f l o w around the p r i ~ l a h~ ej a t exchanger t o r e d u c e t h e temperature of t h e salt e n t e r i n g t h e steam g e n e r a t o r . S t e a m a t t e m p e r a t i o n and secondary s a l t bypass were the s u b j e c t o f a d d i t i o n a l s t e a d y - s t a t e analysfs of fie p l a n t concept. E i t h e r scheme or a combination of t h e two app-rs to permit t h e e s t a b l i s h m e n t of a c c e p t a b l e p a r t - l o a d o p e r a t i n g conditions

12.3.3.3

Analysis o f t r a n s i e n t behavior

The models d e s c r i b e d have been used f o r t r a n s i e n t a n a l y s i s of the p l a n t and proposed comt%ol schemes. The power o p e r a t i n g r a n g e f o r a t y p i c a l p l a n t i s expected t o range from a p p r o x i m ~ t t e l y20X t o 188% of f u l l d e s i g n Isad. Throughout t h i s l o a d r a n g e t h e steam temperature t o t h e t u r b i n e t h r o t t l e must b e h e l d e s s e n t i a l l y c o n s t a n t , t h e primary-and secondarysalt temperatures and f l a w rates must b e kept w i t h i n a c c e p t a b l e l i m i t s , and the r e s u l t i n g stresses due to h d u c e d thermal g r a d i e n t s must remain within a c c e p t a b l e r a n g e s . A m a s t e r l o a d p r o g r a m e r may b e needed t o d i v i d e t h e r e q u i r e d l o a d demand among t h e m u l t i p l e c o o l a n t Poops and steam g e n e r a t o r s . It should b e possible to o p e r a t e t h e plant a t p a r t i a l l o a d s by o p e r a t i n g SOTIE loops a t 100% c a p a c i t y w h i l e o t h e r l o o p s d e l i v e r no power. The c o n t r o l s t u d i e s have shown t h a t s t a b l e p l a n t l o a d c o n t r o l may be accomplished u s i n g two b a s i c c o n t r o l Poops: a steam temperature c o n t r o l l e r and a r e a c t o r o u t l e t temperature c ~ n t ~ o l l e r To . a c h i e v e c l o s e c s n t r o P of steam temperature d u r i n g l o a d t r a n s i e n t s i t i s n e c e s s a r y t o vary t h e s e c o n d a r y - s a l t f l o w r a t e i n t h e steam gemerator. An a d d i t i o n a l c o n t r o l subsystem may b e n e c e s s a r y i f a salt bypass valve i s used in o r d e r t o m a i n t a i n t h e d e s i r e d c o o l a n t s a l t temperatures. me r e a c t o r o u t l e t t e m p e r a t u r e c o n t r o l l e r examined w a s a i m i ~ a rt o t h a t used s u c c e s s f u l l y on the MSRE. 17

A l o a d demand signal determines t h e r e a c t o r o u t l e t temperature set p o i n t . The measured r e a c t o r i n l e t temperature i s s u b t r a c t e d from the reactor o u t l e t temperature set p o i n t , and since the p ~ i ~ ~ r y - s aflow l t rate i s c o n s t a n t , a r e a c t o r power set p o i n t i s g e n e r a t e d by m u l t i p l y i n g this AT by a p r o p o r t i o n a l i t y c o n s t a n t . "he measured v a l u e of r e a c t o r power (from n e u t r o n flux) is compared w i t h t h e r e a c t o r power set p o i n t , and any e r r o r

12-13 i s f e d t o t h e control. rod servo f o r a p p r o p r i a t e r e a c t i v i t y adjustment. The r e a c t o r power set p o i n t , g e n e r a t e d f r o m t h e o u t l e t temperature, i s a f u n c t i o n of t h e r e a c t o r i n l e t temperature d u r i n g a t r a n s i e n t and thus a f u n c t i o n of dynamic l o a d . There are c e r t a i n l y o t h e r p o s s i b l e c o n t r o l schemes f o r a c h i e v i n g s a t i s f a c t o r y p l a n t p e r f o m a n c e . h a l o g s i m u l a t i o n s have shown that ar? i n t e g r a t e d c o n t r o l scheme i s e s s e n t i a l t o good performance. If excessive thermal ~ t ~ e s s eare s produced by t h e t r a n s i e n t s t h a t accompany load changes, they can be reduced by v a r y i n g t h e primary s a l t flow r a t e as a f u n c t i o n of l o a d . The mal% i s o t h e r m a l temperature eoef f i s i e n t of r e a c t i v i t y i m p l i e s t h a t o n l y modest amounts of c o n t r o l r e a c t i v i t y a r e needed to accomplish p l a n t l a a d maneuvering. For t h e reference d e s i g n , a t y p i c a l maneuver from 58% t o 100% power at a r a t e of 5%/min r e q u i r e d 8.05% 6k/k and a r a t e of The maximm system temperature rate of change f o r t h i s Q.OOOlI/sec &/k. t r a n s i e n t was about 0.3"P/sec a t t h e reactor o u t l e t .

12.3.3.4

Accident a n a l y s e s

The m o s t l i k e l y abnornaaI power e x c u r s i o n s would r e s u l t from sudden changes i n load demncl o r r a p i d changes i n s a l t f l o w r a t e i n e i t h e r t h e p r i m a r y o r secondary system, as a result of pump o r power f a i l u r e . A few limited cases of t h i s t y p e have been examined on t h e hybrid s i m u l a t i o n . Some l e s s - l i k e l y r e a c t i v i t y ammalies were a l s o b r i e f l y examined on t h e hybrid model. Conceivable r e a c t i v i t y changes may result from primary f l o w varia t i o n , f u e l a d d i t i o n a c c i d e n t s , c o r e geometry changes, or f a i l u r e o f one o r more c o n t r o l rods.

..&

A r e a c t o r s h u t d ~ wo ~r p r o t e c t i o n system must be coordinated with t h e s a l t c i r c u l a t i o n Poops and t h e steam p l a n t . I f t h e l o a d i s suddenly l a s t , t h e r e a c t o r power g e n e r a t i o n must be reduced t o a v o i d o v e r h e a t i n g . S i m i l a r i l y , i f the r e a c t o r is shut down the steam load m u s t be quFckly reduced t o avoid subcooPing o r f r e e z i n g of the s a l t . S i m i l a r s i t u a t i o n s a r i s e due to s a l t c i r c d a t i o n p a p f a i l u r e . For example, i f primary flow i s Isst, followed by a n a p p r o p r i a t e r e d u c t i o n i n l o a d demand and r e a c t o r power, t h e p ~ i m r ys a l t c o u l d s t i l l f r e e z e i n t h e heat exchangers because of t h e i n c r e a s e d r e s i d e n c e t i m e u n l e s s secondary f l o w i s a l s o reduced.

The p l a n t e i ~ ~ ~ g pe ~ ~ r c~ y~ e cdl e~a ~r l ye sw i l l b e somewhat complex because of t h e high s a l t f r e e z i n g temperatures, and a c a r e f u l a n a l y s i s will. b e needed t o d e r i v e s a t i s f a c t o r y s o l u t i o n s .

12-14

0% a s y s t e m c o n t a i n i n g a few g r a p h i t e r o d s , as proposed f o r t h e r e f e r e n c e design e

Some e v e n t s may b e a n t i c i p a t e d t h a t would r e q u i r e a d d i t i o n a l n e g a t i v e r e a c t i v i t y o r r e a c t i v i t y r a t e s beyond the c a p a b i l i t y of t h e g r a p h i t e r o d s alone. P o i s o n r o d s c ~ u l db e used t u p r o v i d e t h i s a d d i t i o n a l However, r e a c t i v i t y c o n t r o l and t o p r o v i d e s u b s t a n t i a l shutdown margin h a v i n g p o i s o n r o d s i n the c o r e d u r i n g normal o p e r a t i o n i s u n d e s i r a b l e because of t h e i r a d v e r s e e f f e c t on b r e e d i n g . The p o i s o n r o d s w i l l proba b l y b e h e l d uts si de of t h e c o r e poised. f o r r a p i d shutdown i f needed. They may a l s o h e u s e d for a d d i t i o n a l shimming d u r i n g c o r e l o a d i n g o r % o r o t h e r ~ p e r a t i ~ no sr a b n o m a l i t i e s b u t t h e e x p o s u r e a t power w i l l b e s h o ~ t and t h e e f f e c t on b r e e d i n g and rod l i f e w i l l be small. W e do n o t p r e s e n t l y a n t i c i p a t e t h a t e x t r e m e l y f a s t i n s e r t i o n , o r "scram" of t h e r o d s w i l l b e n e c e s s a r y , a l t h o u g h r e l i a b l e i n s e r t i o n m u s t be a s s u r e d .

E!:

3.4

S t a t u s sf i n s t r u m e n t a t i o n development

12.3.4.1

High-teinperature

flux S ~ ~ S Q L T S

I n t h e r e f e r e n c e NSBR, t h e e n t i r e reactor c e l l w i l l o p e r a t e a t a b o u t EOOO"F. Thus any n u c l e a r d e t e c t o r s whish a r e l o c a t e d i n t h i s s p a c e m u s t b e capable of o p e r a t i n g a t such h i g h t e m p e r a t u r e o r else t h e y must b e I% i n - c o r e d e t e c t o r s a r e r e q u i r e d t h e service c o n d i t i o n s w i l l cooled be even more severe. N e d e t e c t o r s a r e p r e s e n t l y a v a i l a b l e f o r o p e r a t i o n above 98Q"F, and even f o r t h e h i g h e r t e m p e r a t u r e s o n l y s p e c i a l developm e n t a l models e x i s t . Similar problems e x i s t i n t h e Hiquid m e t a l f a s t breeder r e a c t o r program, and development work i s b e i n g done. It may b e p o s s i b l e to l o c a t e i o n i z a t i o n chambers in s p e c i a l l y c o o l g d W @ b l s Or t h i m b l e s l o c a t e d o u t s i d e t h e r e a c t o r v e s s e l . For u s e i n t h e r e a c t o r p r o t e c t i o n s y s t e m s , such chamber wells would have t o be d e s i g n e d w i t h t h e same performance r e l i a b i l i t y as r e q u i r e d of the p r o t e c t i o n s y s t e m , s i n c e f a i l u r e 0% t h e c o o l i n g s y s t e m s would b r i n g a b o u t f a i l u r e of t h e detectors. a

Neutron f l u c t u a t i o n a n a l y s i s proved to be a v a l u a b l e t o o l f o r m o n i t o r i n g U n f o r t u n a t e l y one of t h e r e q u i r e anomalous b e h a v i o r i n t h e MSW 9 ments €81- o b t a i n i n g good r e s u l t s w i t h this t e c h n i q u e i s a h i g h d e t e c t i o n e f f i c i e n c y f o r core-coupled n e u t r o n s . While IIO d e t a i l e d c a l c u l a t i o n s have b e e n macle s f n e u t r o n f l u x e s o u t s i d e t h e r e f l e c t o r and vessel, i t i s p o s s i b l e that i n t h e MSBR t h e s e f l u x e s w i l l b e t o o Pow t o p r o v i d e t h e d e s i r e d S i g n d - t Q - n o i s e r a t i o f o r some t y p e s of f l u c t u a t i o n a n a l y s i s . A l l of t h e proposed n u c l e a r d e t e c t o r l o c a t i o n s are w i t h i n t h e h i g h t h e problem of t e m p e r a t u r e p r i m a r y c o n t a i n m e n t oven and have i n ~0~11111~61 c o n t a i n m e n t p e n e t r a t i o n seals. G e n e r a l l y , t h e s p e c i f i c a t i o n s ~ Q peneP t r a t i o n s f a r n U C l @ ; k % d e t e c t o r s a r e mere demanding that t h o s e for p r o c e s s s e n s o r s b e c a u s e 0% t h e t y p i c a l l y v e r y s m a l l s i g n a l c u r r e n t s d e l i v e r e d . The l o c a t i o n and d e t a i l e d r e q u i r e m e n t s of these p e n e t r a t i o n s have not y e t been d e t e r m i n e d , b u t the need f o r some development work in this area

.... .... . . . d

12-15 .... . .x

i s a n t i c i p a t e d , The s i g n a l t r a n s m i t t i n g l i n e s w i l l r e q u i r e s p e c i a l d e s i g n and some development b e c a u s e of t h e h i g h - t e m p e r a t u r e e n v i r o n m e ~ t .

12.3.4.2 .&

Plant instrumentation

Although MSBR system i n s t r u m e n t a t i o n can r e a s o n a b l y be e x p e c t e d t o r e q u i r e sone d e s i g n s beyond t h e present s t a t e of the a r t , no problems are f o r e s e e n t h a t could n e t b e r e s o l v e d by f u r t h e r development of components and t e c ~ i n i q u e es 2 3 1 9 Many i n s t r u m e n t c ~ m p o n e n t su s e d s u c c e s s f u l l y i n t h e PEE and o t h e r s b e i n g developed f o r t h e LMFBR w i l l b e d i r e c t l y a p p l i c a b l e t o S i m i l a r l y e x p e r i e n c e b e i n g g a i n e d by t h e u t i l i t i e s i n d u s t r y t h e MSBR w i t h i n s t r u m e n t a t i o n o f s u p e r c r i t i c a l p r e s s u r e steam s y s t e m s w i l l b e appEicab1e t o t h e MSBR. a

,.&

MSBK p r o c e s s i ~ s t r ~ m e n t a t li o~c~a tne d o u t s i d e t h e b i o l o g i c a l l y s h i e l d e d areas and n o t a n i n t e g r a l p a r t o f t h e c o n t a i n m e n t s y s t e m can b e convent i o n a l equipment, Some s t a n d a r d components, however, may r e q u i r e upg r a d i n g , and a s t r i c t q u a l i t y c o n t r o l program w i l l be r e q u i r e d to e n s u r e a l e v e l of r e l i a b i l i t y and performance commensurate with MSBR r e q u i r e m e n t s

A l l p r o c e s s i n s t r u m e n t a t i o n components l o c a t e d w i t h i n t h e c o n t a i n m e n t c e l l s o r as a n i n t e g r a l p a r t of t h e contaiinmeiat s y s t e m p r o b a b l y s h o u l d b e c o n s i d e r e d d e v e l o p m e n t a l . These components are p r e d o m i n a n t l y primary s e n s i n g e l e m e n t s f o r measurement of flow r a t e s , p r e s s u r e s s l e v e l s , w e i g h t s , and t e m p e r a t u r e s i n t h e s a l t - c o n t a i n i n g p i p e s and vessels, i n t h e a s s o c i a t e d p u r g e and o f f - g a s s y s t e m s , and i n t h e s a l t c h e m i c a l p r o c e s s i n g f a c i l i t i e s . O t h e r such components are f i n a l c o n t r o l e l e m e n t s (such as off-gas c o n t r o l v a l v e s ) , lead-wFre and p i p i n g c o n n e c t i o n s t o t h e s e n s i n g s containment and final C o n t r o l e l e m e n t s r e m o t e l y o p e r a t e d d i s c ~ n ~ e c t and penetration seals. The e l e c t r i c a l c o n d u c t i v i t y of t h e MSBR s a l t s w i l l be a f a c t o r i n s e l e c t i n g t h e t y p e of p r i m a r y s e n s i n g e l e m e n t s t h a n can b e u s e d . The c o n d u c t i v i t i e s of MSBR s a l t s are e s t i m a t e d to b e a b o u t 1 mho/cm - about the same as MSRE: salts This neans, f o r examples t h a t m a g n e t i c f l s m e t e r s p r o b a b l y c a n n o t b e u s e d , and m o s t of t h e d e v i c e s w i l l b e similar t o t h o s e u s e d on t h e MSm. e

....

... .... ,3*

Some development w i l l be r e q u i r e d to a d a p t MSRE c o n t r o l ~ o m p ~ n e n t so t h e h i g h e r p r e s s u r e s and t e m p e r a t u r e s t h a t w i l l e x i s t i n ~ O P ~ ~ O of R Sthe MSBR. Development of o t h e r equipment and t e c h n i q u e s , s u c h as e l e c t r i c a l p e n e t r a t i o n s i n t ~s a l t - c o n t a i n i n g p i p e s and vessels, would undoubtedly l e a d t o i m p r ~ v e di n s t r u m e n t a t i o n .

12.3.4.3

S a l t throttling valves

One 0% the more promising p l a n t c o n t r o l schemes depends upon t h r o t t l i n g ......,

a , . . ,

..., .;.i.3

.......

i...

(Tight i n a s e c o n d a r y s a l t b y p a s s around t h e p r i m a r y h e a t e x c h a n g e r . shut-off 1 s n e t r e q u i r e d of t h e v a l v e i n t h i s b y p a s s . ) The maximum and

12-16 minimum flow r a t e s and t h e r a t e of change ~f f l o w rake n e c e s s a r y to a c h i e v e satfsfactsry p l a n t c o n t r o l will need t o be f a c t o r e d f n t o t h e development of a v a l v e for t h i s service.

1s* 3 . 4 . 4 The r e f e r e n c e d e s i g n i n c l u d e s t h e r e a c t o r , f o u r p r i m a r y l o o p s , f o u r secondary l o o p s , each having f o u r r e h e a t e r s a d f o u r s t e m g e n e r a t o r s , and a m u l t i - s t a g e t u r b i n e . A l l of the l o o p s i n t e r a c t o r r e q u i r e respons i v e a c t i o n from other l o o p s when p e r t u r b e d , and t h e c o r r e c t a c t i o n t o t a k e may n o t be simp3.y p e r c e i v e d . Computer c o n t r o l and s u r v e i l l a n c e of t h e p l a n t i s d e s i r a b l e t o relieve t h e o p e r a t o r s ~f d i f f i c u l t t a s k s and can be expected t o improve t h e safety and reliability of operation. Design planning should i n c l u d e from t h e beginning provisisns f o r optimum u t i l i z a t i o n of computer t e c h n i q u e s .

....

C.F&

The i n s t r u m e n t a t i o n requirements of a full-scale chemical prsceesing plant have r e c e i v e d only minimal a t t e n t i o n from i n s t m m e n t d e s i g n e r s The p r ~ c e s s e sinvolved have been instrumented and c o n t r o l l e d on l a b o r a t o r y QP: p i l o t plant scales, b u t no: w i t h the volumes and r a d i a t i o n levels expected in t h e f u l l - s c a l e p l a n t . Early e v a l u a t i o n of p o t e n t i a l problems i s needed t o e n a b l e i n i t i a t i o n of r e q u i r e d development a timely b a s i s .

12.4

TASK GROUP 11.1 CONTROL ANALYSES

The work in t h i s task group is concerned with t h e a n a l y s i s and d e v e ~ s p m e m t

of c o n t r o l systems r e q u i r e d f o r MSBR o p e r a t i o n under s t a r t u p , standby , p a r t I s a d , f u l l l o a d , shutclown, and a c c i d e n t c o n d i t i o n s i n a lQOQ-PlW(e) MSBR; and t h e c h a r a c t e r i z a t i o n of MSBR o p e r a t i o n w i t h c o n t r o l systems showing t h e g r e a t e s t p o t e n t i a l m

12.4.1

Obieetive

The o b j e c t i v e of t h i s t a s k group i s t o develop t h e n e c e s s a r y technology r e q u i r e d f o r d e s i g n of c o n t r o l systems for a l O O O - ~ ( e ) MSBR, and t~ i d e n t i f y the o p e r a t i n g c h a r a c t e r i s t i c s of t h e r e a c t o r system i n s u f f i c i e n t d e t a i l t o g u i d e P r o g ~ ma c t i v i t i e s i n areas i n c h ing the development and t e s t i n g of materials, development of h i g h temperature d e s i g n methods and data, Safety ikI%E3lySeSpand CQfnpQflent deVelOpment.

12 4 2 0

Schedule

The s c h e d u l e f o r work i n this t a s k group i s g i v e n in Table 12.4.2.

k..d

Table

X2.4.2.

Ssbedule

Task cmup

11.1

- COQtmA

Ffssaf

11.1.1 11.1.2 11.1.3 ll.l.4 11.1.5 11.1.6 11.1.7 11.1.8

analyses

year

12-18 12.4 - 3

Funding

Tlae o p e r a t i n g funds r e q u i r e d by t h i s t a s k group a r e summarized i n T a b l e 12.4 3 0

12.4.4

.... e.=.

The work i n this t a s k w i l l be d i r e c t e d toward the development of improved computer representatiom of the MSBR p r i m v , secundary, and steam s y s t e m and t h e c o n t r o l system whish i n f l u e n c e t h e i r o p e r a t i o n . Analog and hybrid computer s i m u l a t i o n s along e t h d i g i t a l computer r e p r e s e n t a t i o n s will be extended o r developed as n e c e s s a r y to allow dynamic and c o n t r o l s t u d i e s r e q u i r e d f o r c h a r a c t e r i z i n g t h e o p e r a t i o n of an MSBR under a variety of operating c o n d i t i o n s , It i s b e l i e v e d t h a t analog modeling can b e used to advantage when d e t e r m i n i n g general system b e h a v i o r , however, d i g i t a l r e p r e s e n t a t i o n s will b e r e q u i r e d for t h e more complex and d e t a i l e d c a l c u l a t i o n s necessary f a r f i n a l e v a l u a t i o n and s t u d y of reactor plant operatism The computer r e p r e s e n t a t i o n s t h u s developed w i l l b e s u f f i c i e n t l y g e n e r a l t o a l l o w s t u d y of a l t e r n a t e c o n t r o l methods and s y s t e m , and will b e s u f f i c i e n t l y d e t a i l e d that meaningful c h a r a c t e r i z a t i o n s sf r e a c t o r plant o p e r a t i o n can b e o b t a i n e d f o r t h e purposes o f s p e c i f i c a t i o n of o p e r a t i n g transients f o r component d e s i g n s t u d i e s , d e t e m i n a t i o n of materials r e q u i r m e n t s and p ~ o k & l e service c o n d i t i o n s and some a c c i d e n t a n a l y s i s work ~

12.4.5

Task 1 1 . 1 . 2

Development of c o n t r o l methods

S t u d i e s w i l l b e c a r r i e d out: u s i n g t h e computer r e p r e s e n t a t i o n s sf MSBR systems developed i n Task l l e l a lt o i d e n t i f y and i n v e s t i g a t e various CORt r o l methods which a d e q u a t e l y decsraple l o a d e f f e c t s and temperature l e v e l s ~ 0 t hs t e a d y s t a t e and t r a n s i e n t c o n d i t i o n s w i n be examined. studie-s w i l l be c a r r i e d o u t i n i t i a l l y i n s u f f i c i e n t d e t a i l t o demonstrate the f e a s i b i l i t y o f one o r more c o n t r o l methods, and s y s t e m showing t h e g r e a t e s t potential. w i l l b e i n v e s t i g a t e d i n greater d e t a i l . C o ~ ~ t ~ o l methods which will be c o n s i d e r e d i n c l u d e : (1) a l l o w i n g the steam ternperature t o increase above t h e H860'F d e s i g n p o i n t as t h e load d e c r e a s e s , w i t h subsequent a t t e m p e r a t i o n o f t h e s t e r n with i n j e c t e d f e e d w a t e r ; (2) increasing the f e e d water tmperature above i t a ~ O O d~e sPi g n p o i n t as t h e l o a d decreases; ( 3 ) reducing t h e number sf steam g e n e r a t o r s i n o p e r a t i o n as t h e l o a d decreases; and ( 4 ) by-passing some of t h e secondary s a l t a r o m d t h e primary h e a t exchanger t o reduce t h e t e m p e r a t u r e of the s@CUlldZLry S d t enteK%Hlg t h e §t@aTDg@nePSitOPs.

12.4.6

Task 1P.l.3

Flux measur@ment a n a l y s e s

The work i n t h i s t a s k w i l l b e d i r e c t e d toward d e t e r m i n i n g t h e accuracy with which core-coupled flux measurements can b e made in an MSB d e f i n i n g t h e e x t e n t and t y p e of i n f o r m a t i o n which c a n be o b t a i n e d through a n a l y s i s of neutron f l u c t u a t i o n data. P a r t i c u l a r a t t e n t i o n e d P l b e given

x ,.;.;.;_ .

Table

12.4.3.

Operating

fmd

requirements for Task Group lB.1 (costs im 1000 dollars)

1977 Computer Qperatiom

representation

Development Fhx

measurement

Pressure transients Salt

of sontrol

Total

operating

year

1978

1979

19 80

19 81

1982

1983

1984

P98.5

of plant methods

analyses

throttling

valves

asssunting control

scram

Processing

Fdssal

analyses

and temperature

Reactivity inventory Fast

- Control

funds

for

amd

capability pliant

instrumentatian Task Group 11.1

30 40

141

210

280

295

250

1986

12-20 t o u s e of t h i s approach f o r o b t a i n i n g long-term r e a c t i v i t y measurements. S u f f i c i e n t work w i l l be c a r r i e d out: t o d e t e r m i n e w h e t h e r out-of-core measurements w i l l s u f f i c e , and t o d e t e r m i n e t h e c h a r a c t e r i s t i c s of an a c c e p t a b l e measurement system.

12.4.7

Task 11.1.4

C a l c u l a t i o n of p r e s s u r e and t e m p e r a t u r e t r a n s i e n t s

The work i n t h i s t a s k w i l l be d i r e c t e d toward c a l c u l a t i n g t h e p r e s s u r e and t e m p e r a t u r e t r a n s i e n t s a t a number 5f c r i t i c a l Pocations i n t h e v e s s e l s and p i p i n g d u r i n g a f u l l l o a d , p a r t l o a d , changing l o a d , and a c c i d e n t c o n d i t i o n s f o r t h e m ~ r ep r o m i s i n g c o n t r o l methods i n o r d e r t o h e l p g u i d e t h e development of t e c h n o l o g y r e l a t e d t o materials development and e v a l u a t i o n , development sf h i g h t e m p e r a t u r e d e s i g n methods a n d d a t a , component d e s i g n and t e s t i n g and s a f e t y analyses a

12.4.8

Task 11.1.5 valves

D e t e r m i n a t i o n of r e q u i r e m e n t s f o r s a l t t h r o t t l i n g

The work i n t h i s t a s k w i l l be d i r e c t e d toward c h a r a c t e r i z i n g the r e q u i r e ments f o r salt t h r o t t l i n g v a l v e s which a r e employed i n o n e of the more p r o m i s i n g p l a n t c o n t r o l schemes. s he kaxfmurn and mFnimum f l o w rates and t h e r a t e of change of flow r a t e n e c e s s a r y t o a c h i e v e p l a n t c ~ n t r o w l ill be d e t e r m i n e d , and other c h a r a c t e r i s t i c s of t h e valves d e t e r m i n e d as necessary.

12.4.9

Task 11.1.6 and c o n t r o l

Development of methods f o r i n v e n t o r y a c c o u n t i n g

The work in t h i s t a s k will be d i r e c t e d toward d e v e l o p i n g methods f o r m a i n t a i n i n g a long-tern r e a c t i v i t y b a l a n c e i n an MSBR system. The establ i s h e d t e c h n i q u e of a c c o u n t i n g f o r all s i g n i f i c a n t r e a c t i v i t y a d d i t i o n s and w i t h d r a w a l s fsorn t h e r e a c t o r s y s t e m , i n c l u d i n g t h e c a l c u l a t i o n of b u i l d u p and b u r n o u t 5f p o i s o n s , w i l l be c o m p l i c a t e d i n an MSBR b e c a u s e many f a c t o r s that can a f f e c t r e a c t i v i t y may n o t be d e t e r m i n a b l e i n a system u t i P i z i n g c o n t i n u o u s f u e l p r o c e s s i n g . Methods based on s u b c r i t i c a k i t y D E ~ S U K ~ W T I ~will S b e considered. The a c c u r a c y with which a l o n g t e r m r e a c t i v i t y b a l a n c e can be e s t a b l i s h e d will be d e f i n e d i n o r d e r t o p r o v i d e Program g u i d a n c e i n t h e areas of t e c h n o l o g y development r e l a t e d t o c o n t r o l s y s t e m s and equipment and t o s a f e t y a n a l y s e s .

12.4.18

Task ll.E.7

E v a l u a t i o n of need f o r f a s t scram c a p a b i l i t y

The work i n t h i s t a s k w i l l b e d i r e c t e d t o e v a l u a t i n g t h e n e e d f o r f a s t scram c a p a b i l i t y i n MS R systems, and t o d e f i n i n g the consequences of f a s t scrm i n terns of system t r a n s i e n t s and t h e e f f e c t s on c o n t r o l s y s t e m s , components, and system t e m p e r a t u r e s and p r e s s u r e s .

... .'i.x

12-21 12.4.11

Task l l . P . 8 needs

Determination of p r o c e s s i n g p l a n t i n s t r u m e n t a t i o n

The work in t h i s task w i l l b e d i r e c t e d ~ C Jdetermining the i n s t r u m e n t a t i o n r e q u i r e d for s a f e and e f f i c i e n t o p e r a t i o n of t h e f u e l p r o c e s s i n g system.

12.5

TASK GROW 11.2

12 .5.1

0b-J ec t i v e

INSTRUMENTATION DEVELOPMENT

The o b j e c t i v e of t h i s task group i s t o develop t h e technology r e q u i r e d f o r d e s i g n and s p e c i f i c a t i o n of i n s t r u m e n t a t i o n for a PQBO-Nd(e) MSBR. 12.5.2

Schedule

The s c h e d u l e f o r t h i s t a s k group i s shown i n Table 62.5.2. ,...., <,A

12.5.3 ...., .!.m

Funding

The o p e r a t i n g funds r e q u i r e d by t h i s t a s k group are S ~ Q Wi n~ Table 12.5.3. C a p i t a l equipment funds i n the amount of $170,000 w i l l b e r e q u i r e d d u r i n g PY 1980 for d e s i g n and c o n s t r u c t i o n ~f t h e I n s t r u m e n t a t i o n T e s t F a c i l i t y .

.Z.&

12.5 ..le

Facilities

.... .....

Molten-salt b r e e d e r r e a c t o r s w i l l need i n s t r u m e n t a t i o n f o r s e n s i n g flows, t e m p e r a t u r e s , p r e s s u r e s , l i q u i d levels, and o t h e r parameters i n molten salts a t temperatures as high as 750°C. Such i n s t r u m e n t a t i o n , s a t i s f a c t o r y f o r u s e i n a n MSBR, does not p r e s e n t l y exist. Much o f the t e s t i n g of I n s t r u m e n t a t i o n that is developed w i l l be done in f a c i l i t i e s p r o d d e d f o r t e s t i n g of major components. A s e p a r a t e small f a c i l i t y i s needed for making p r e l i m i n a r y tests QXI models o r p r o t o t y p e s of new se11sars as they a ~ e developed. No f a c i l i t y p r e s e n t l y e x i s t s i n which such tests c o u l d be m d e .

.... ..:.& ;<;.

Ihn i n s t r u m e n t test f a c i l i t y w i l l b e c o n s t r u c t e d which w i l l c o n s i s t o f a s m a l l s a l t c i r c u l a t i o n loop, a set of t a n k s c o n t a i n i n g s a l t f o r s t a t i c tests, essential a ~ ~ i l i a r i e stest , s t a n d s o n which t h e equipment w i l l be mounted, b u s i n g s , and a v e n t i l a t i o n system. "he f a c i l i t y w i l l include t h e inSfZrkurnen%E€t$Qn and CQHntKOPs necessaq f o r o p e r a t i o n sf t h e e g u i p g f l t .

iyll

Table

X2.5.2.

Schedule

for

Task

Group

11.2

- Instrumentatian Fiscal

development year

-v-----I--

11.2.1

-.---.:.

.-__.

, 11.2.2

11.2.3

Improved pressure, flow, and level devices 11.2.2"B Direct pressure transmitters 11.2.2.2 Direct flow measuremenes 11.2.2.3 Improved level devices Assessment availability

instrumentatian

/ I 1 .,._

.-; ..^

! I ! -,.._.

I-.

..-...i i

_ .-

Table

12.5.3.

Operating

fund

requirements (costs

for Task Group 1QQQ dollars)

1979 11.2.1.

High

11.2.2

Improved devices 11.2.2.1

11.2.3

Total

temperature

flux

pressure,

11.2.2.2 11.2.2.3 Subtotal

far

operating

11.2.2.2 of

funds

Instrumentation

development

year

1981

1982

198%

1984

1985

100

20 20 28 60

20 20 20 60

50 50 50

200

60 60 8Q

_ I.50

150

60 60 80

200

30 250

50 %QQ

50 I_ 350

50 350

198Q

and Bevel

Direct pressure transmitters Direct flow measurements Improved level devices

Assessment availability

Fiscal

sensors

flow,

11.2

instrumentation

for

Task

Group

11.2

1986

12-24

Cover gas w i l l b e o b t a i n e d from a system used by several f a c i l i t i e s . Off-gas will be d i s c h a r g e d t o a c o m n off-gas system. The f a c i l i t y w i l l p r o v i d e f o r simpbe s t a t i c and dynamic tests of models and protoypes o f r e a c t o r i n s t r u m e n t s as t h e y are developed. Simple therm1 transient and t h e m l c y c l i n g tests can b e made p r i o r t o more e l a b o r a t e and e x t e n s i v e tests i n o t h e r faelllties. E l e c t r f c a k h e a t i n g and a i r c ~ ~ b i f w2ll lg be provided s o that t e s t i n g can be done a t t e m p e r a t u r e s from t h e liquidus temperature of t h e s a l t i n u s e (as low as 350°C) t o 750°C. This a c t i d t y will r e q u i r e o b l i g a t i o n of $170,800 i n Fy 1980.

12.5.5

Task 11.2.1

c"' v

Development of high temperature f l u x S ~ I ~ S O P S

The work i n this task will b e d i r e c t e d t o t h e development of d e v i c e s f o r measurement of n e u t r o n f l u x level a t t e m p e r a t u r e s of lBhbO"F, 8% h i g h e r i f n e c e s s a q , which w i l l m e e t the high s t a n d a r d s o f r e l i a b i l i t y ~ e q d r e d f o r Use in MSBR c o n t r o l and p r o t e c t i o n s y s t e m . Attention W i l l a l s o be given t o the requirement t h a t t h e flux s e n s o r s and a s s o c i a t e d s i g n a l t r a n s m i t t h g l i n e s m u s t o p e r a t e i n a h i g h - t e ~ ~ ~ p e ~ ah ti guh~- r, a d i a t i o n level envirsnnent. P r o t o t y p i c flux sensors will b e f a b r i c a t e d and t e s t e d under r e p r e s e n t a t i v e conditions for rnBR a p p l i c a t i o n .

d e v i c es The work i n t h i s t a s k dll b e d i r e c t e d t o the development of improved ~ ,~ and level d e v i c e s which w i l l allow direct measurement of P P ~ ~ S U fK low i n the primary and secondary s a l t C ~ K C L L ~of ~ S an MSBR.

12.5.6.1

Subtask 11.2.2.1 transducers

Direct d i f f e r e n t i a l and a b s o l u t e p r e s s u r e

The work i n t h i s subtask will be d i r e c t e d to t h e development of d e v i c e s and t e c h n i q u e s allowing the d i r e c t measurement of differential and absol u t e p r e s s u r e i n IVISBR primary and secondary s a l t c i r c u i t s , and which are c a p a b l e of ~ p e b - a t i o na t IQ00-13QO°F P o t e n t i a l approaches for these t r a n s d u c e r s w i l l b e i d e n t i f i e d , and t h e more promising approaches w i l l b e c o n s i d e r e d i n d e t a i l . P ~ o t o t p F ct r a n s d u c e r s w i l l . b e c o n s t r u c t e d for P ~ n g - t e ~testlng m t a n d e ~servlce c o n d i t i o n s a n t i c i p a t e d i n M§R s y s t e m .

12.5.6.2

Subtask 1 1 . 2 . 2 . 2

Direct primary c i r c u i t f l o w measurements

S e v e r a l of t h e mre promising methods f o r MSBW c o n t r o l u t i l i z e v a r i a b l e flow of f u e l s a l t through p o r t i o n s of t h e p ~ i m qc i r c u i t . Utilization of t h e s e methods will be dependent upon t h e a v a i l a b i l i t y of h i g h l y rel i a b l e i n s t r u m e n t a t i o n a l l o w i n g the d i r e c t m a s ~ r t i ~ of ~ n st a l t f l o w r a t e a t one O K mare points i n t h e r e a c t o r primary c i r c u i t ; such i n s t r u m e n t a t i o n does not now exist. The work i n t h i s subtask w i l l b e d i r e c t e d i n i t i a l l y to t h e P d e n t f f i c a t i O n Sf p o t e n t i d methods f O r d i r e c t flow UleaSure~ent

k...

12-25

in t h e primary c i r c u i t , and to t h e selection of t h o s e approaches which o f f e r t h e g r e a t e s t p o t e n t i a l . Development work will be c a r r i e d o u t as necessaq~leading t o t h e f a b r i c a t i o n and t e s t i n g of p ~ o t o t y p i cd e v i c e s under service c o n d i t i o n s a n t i c i p a t e d i n MSBR systems

The level-measurement d e v i c e s employed i n t h e MSW w e r e based l a r g e l y on t h e i n d i r e c t measurement of level via measurement of gas p r e s s u r e i n bubbler d e v i c e s . While s a t i s f a c t o r y for many a p p l i c a t i o n s i t i s h i g h l y d e s i r a b l e t h a t level d e v i s e s be developed which measure d i r e c t l y t h e s a l t l e v e l a t c r i t i c a l p o i n t s i n an MSBR system. The work in t h i s subtask w i l l b e d i r e c t e d t o i d e n t i f y i n g p o t e n t i a l l e v e l d e d c e s c a p a b l e of d i r e c t measurement, and t o he n e c e s s a r y development of t h e more promising d e v i c e s . The work will sdminate i n the f a b r i c a t i o n and t e s t i n g of p r s t s t y p i c level d e v i c e s which are c a p a b l e of d i r e c t l e v e l measurements and s f o p e r a t i o n a t 1088 t o l306V. 12.5.7

Task 11.2.3

Assessment of i n s t r u m e n t a t i o n a v a i l a b i l i t y

The work i n t h i s t a s k w i l l b e d i r e c t e d to a s s e s s i n g t h e a v a i l a b i l i t y of i n s t r u m e n t a t i o n r e q u i r e d for MSBR o p e r a t i o n and to i d e n t i f y i n where a d d i t i o m l development work w i l l be r e q u i r e d .

..... GY,?

..... rx&

;.:.:..... >

... x.

12-26

REFERENCES FOR SECTION E2

1. 2.

R. C. S t e f f y , Jr. and I". 3. Wood, "Theoretical Dynamic Analysis sf the MSW with 233U F u e l , '' QR

-TM-2571,

J u l y 1969

Et. C. S t e f f y , Jr., ''Experimental Dynamic Analysis o f t h e B R E w i t h 233U F u ~ . , 'ORNL-IN-2997, ~ A p r i l 1996 a

8. 9.

12 13

15.

12-27

16.

.......,

... ....

;?.&

K O Sanathan and A. A. Sandberg, University of I l l i n s i s , ChFcago, I l B i n o i s , and F. H. Clark, 0 . W. Burke, and R. S. Stone, O W E , "Transient Analysis and Design Evaluation sf a Qnce-Thrcsugh Steam Generator with t h e A i d of a Hybrid Comp~ter,'~s u b d t t e d f o r publication in Nuclear Engineering and Design. C.

k,.

13. MOLTEN-SALT TEST REACTQR MOCKl.JP 13.1

.... i.x.s

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INCENTIVE FOR CONSTRUCTION 6kEV OPERATION OF RMCTOR MOCKW

The development work o u t l i n e d i n t h e e a r l i e r s e c t i o n s o f this program p l a n i s aimed a t p r o v i d i n g t h e technology r e q u i r e d f o r d e s i g n of components f o r a m o l t e n - s a l t test r e a c t o r . However, a n u d e r u f important aspects r e l a t e d t o t e s t - r e a c t o r d e s i g n and o p e r a t i o n cannot b e fully demonstrated by t h e o u t l i n e d work. FOP t h i s r e a s o n , it appears d e s i r a b l e t o d e s i g n , c o n s t r u c t , and o p e r a t e a msckup c o n s i s t i n g o f i m p o r t a n t port i o n s of the test r e a c t o r . The systems t o b e mocked up would c o n s i s t l a r g e l y of t h e primary and s e c ~ n d a r yc i r c u i t s f a r t h e r e a c t o r p l u s p s r tions of the s t e a m - r a i s i n g equipment. T h e mockup would b e designed f o r o p e r a t i o n i n principally an i s o t h e r m a l manner and would b e used f o r t e s t i n g sf f u l l - s c a l e p r o t o t y p i c components f o r t h e t e s t r e a c t o r . It i s i n t e n d e d t h a t t h e t e s t r e a c t o r IIIOC~UP would b e o p e r a t e d i n a p a r a l l e l manner t o o t h e r component development f a c i l i t i e s , such as the S t e a m Generator Model 'Pest h s t d k ~ t i o n ,119 which scal@d-doWn Versions of test r e a c t o r components wsuPd b e t e s t e d o v e r t h e full range o f a n t i c i p a t e d O p e r a t i n g COnditfQnS.

Other b e n e f i t s which W Q U accrue ~ ~ from work a s s o c i a t e d with t h e test r e a c t o r muckup include obtaiming e x p e r i e n c e d u r i n g the d e s i g n and cons t r u c t i o n phases which would b e d i r e c t l y a p p l i c a b l e t o t h e test r e a c t o r , p r o v i d i n g an opportunity f o r t e s t i n g of remote maintenance equipment and techniques p r i o r t o t e s t r e a c t o r o p e r a t i o n , and allowing an o p p o r t u n i t y f o r o p e r a t o r t r a i n i n g i n s u p p o r t of t h e test r e a c t ~ r .

13.2

SCHEDULE AND REQUIRED PUNDING

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Table 1%.2.

Qpemratiwg funa Pequirements (costs

fQK mslten-salt Fiscal

Prcsgram assistanbee and construction

during

operating

funds

-reactor msckup

year

design

Operation

Total

test

1(B8Q dslllars)

638

7QQ

8SQ

-----

700

850

1508

1500

25QQ

%QQQ

3800

2SQQ

PQOQ %QQQ

14-1

A number of i m p o r t a n t q u e s t i o n s r e l a t e d t o t h e d e s i g n o f m o l t e n - s a l t b r e e d e r r e a c t o r s can b e answered o n l y through t h e c o n s t r u c t i o n and o p e r a t i o n of a t e s t reactor. These i n c l u d e t h e need f o r a d d i t i o n a l r e a c t o r o p e r a t i n g and maintenance e x p e r i e n c e under c o n d i t i o n s more c l s s e l y resembling m o l t e n - s a l t power r e a c t o r s i n o r d e r to o b t a i n improved estimates f o r t h e a v a i l a b i l i t y apld maintenance c o s t s of m~lten-salt b r e e d e r r e a c t o r s , t h e need f o r o p e r a t i o n of a continuous p r e c e s s i n g system i n which r e p r e s e n t a t i v e q u a n t i t i e s sf p r o t a c t i n i u m and f i s s i o n p r o d u c t s are p r e s e n t , and the need f o r an improved d e f i n i t i o n of t h e b e h a v i o r and d i s t r i b u t i o n of noble-metal f i s s i o n produets i n a r e a c t o r system. F i n a l l y , t h e r e i s t h e need f o r t h e u l t i m a t e demonstration t h a t a s a t i s f a c t o r y material of e o n s t r u e t i ~ nfor t h e reactor primary c i r c u i t h a s been developed and the need f o r e b t ~ i ~ i ne xgp e r i e n c e w i t h d e s i g n , f a b r i c a t i o n , and o p e r a t i o n of larger r e a c t o r components.

N e i t h e r t h e optimum s i z e nor complexity of t h e t e s t r e a c t o r has been determined a t t h i s t i m e - If a t a l l p o s s i b l e , t h e t e s t r e a c t o r should b e s u f f i c i e n t l y large t h a t e x p e r i e n c e can b e o b t a i n e d with components t h a t are f u l l - s c a l e f o r a demonstration r e a c t o r . I t i s a n t i c i p a t e d t h a t t h e p r e l i m i n a r y c o n c e p t u a l d e s i g n s t u d i e s o u t l i n e d i n S e c t i o n 8 of t h i s p ~ o g r ap l~a n~ w i l l l e a d t o a clear d e f i n i t i o n of t h e d e s i g n and o p e r a t i o n a l ~ e q u i r e m e n t sf o r the t e s t r e a c t o r . Pimal design of t h e system will be completed by t h e end s f FY 1985, and o p e r a t i o n should b e g i n e a r l y i n FY 1989. The e s t i m a t e d c o s t f o r d e s i g n and c s n s t r u c t i s n of t h e test This estimate should b e considered t o b e v e r y r e a c t o r i s $450 m i l l i o n . preliminary, s i n c e i t i s n o t supported by d e t a i l e d d e s i g n o r c o s t estimation. Operating fund requirements a s s o c i a t e d w i t h t h e test r e a c t o r through FY 1985 are shown i n Table 14.1.

Table

l4.1.

Operating

fund requirements for (costs in 1QQQ ddlars)

mlten-salt

Fiscal

test

year

reactor

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MOLTEN-SALT DElfONSTBhTION REACTOR

C e n c e p t u a l d e s i g n of a molten-salt d e m o n s t r a t i o n r e a c t o r would be i n i t i a t e d d u r i n g FY 1982 i n s u p p o r t of a r e q u e s t € o r o b t a i n i n g FP 1985 a u t h o r i z a t i o n f e r the design and c o n s t r u c t i o n of a d e m o n s t r a t i o n r e a c t o r .