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S e r i e s A.

C o n t r a c t No. W- 740 5- eng- 26

AIRCRAFT NUCLEAR PROPULSION PROJECT QUARTERLY PROGRESS REPORT for

Period Ending March 10, 1953

R. C. Briant, Director J. H. Buck, Associate Director A. J. Miller, Assistant Director

Edited by: W. B. Cottrell

DATE ISSUED

OAK R I D G E N A T I O N A L LABORATORY Operated by C A R B I D E AND CARBON C H E M I C A L S COMPANY A D i v i s i o n of U n i o n C a r b i d e and C a r b o n C o r p o r a t i o n Post O f f i c e B o x P O a k R i d g e , Tennessee

MARTIN MARIETTA ENERGY SYSTEMS LIBRARIES

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ION

Period Period Period Period Period Period Period Period Period Period Period Period Period

Ending Ending Ending Ending Ending Ending Ending Ending Ending Ending Ending Ending Ending

November 30, 1949 February 28, 1950 May 31, 1950 August 31, 1950 December 10, 1950 March 10, 1951 June 10, 1951 September 10, 1951 December 10, 1951 March 10, 1952 June 10, 1952 September 10, 1952 December 10, 1952

mit tal -or the-dEclo

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TABLE OF CONTENTS FOREWORD

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PART I.

1

REACTOR THEORY AND DESIGN

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CIRCULATING-FUEL AIRCRAFT REACTOR EXPERIMENT . , . , . , , Fluidcircuit... .......................

Stress Analysis . . . . . . . . . . . . . . . . . . . . . . . . .

Reactor., . . . . . . . . . . . . . . . . . . . . . . . . . . .

Instrumentation .. . . . . . .. . . .

Off-Gas S y s t e m . . . . . . . . . . . . . . . . . . . . . . . . .

ReactorControl. . . . . . . . . . . . . . . . . . . . . . . . .

E l e c t r i c a l System . . . . . . . . . . . . . . . . . . . . . . . .

INTRODUCTION AND SUMMARY

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EXPERIMENTAL REACTOR ENGINEERING e e e e e e o v Pumps f o r H i g h - T e m p e r a t u r e L i q u i d s C e n t r i f u g a l pump w i t h c o m b i n a t i o n packed and f r o z e n s e a l for fluorides A l l i s - C h a l m e r s c e n t r i f u g a l pump f o r l i q u i d m e t a l s e e L a b o r a t o r y - s i z e pump w i t h g a s s e a l e e e e e e e A R E - s i z e sump pump e e e e e e ARE c e n t r i f u g a l pump e e e e e + e e a .

E l e c t r o m a g n e t i c pump e R o t a t i n g - S h a f t and V a l v e - S t e m - S e a l Development e e e e .

Mechanical f a c e s e a l s e e e e e e e , e C o m b i n a t i o n packed and f r o z e n s e a l w i t h MoSz e e , C o m b i n a t i o n packed and f r o z e n s e a l w i t h g r a p h i t e .

G r a p h i t e packed s e a l e Rotating-shaft seal test .

Packing p e n e t r a t i o n t e s t s , e e e e e F r o z e n - s o d i u m and f r o z e n - l e a d s e a l f o r NaK e e AREvalvetest H e a t Exchanger S y s t e m s Sodium-to-air r a d i a t o r t e s t s a e B i f l u i d heat t r a n s f e r loop ARE F u e l C i r c u i t Mockup V o r t e x e s and b u b b l e s Operational i n s t a b i l i t i e s Instrumentation e , , e e e e e e .

P r e s s u r e measurement ARE l e a k d e t e c t i o n i n d ’ tests

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REACTOR PHYSICS. . . . . . . . . . . . . . . . . . . . . . . . . . .

REFLECTOR-MODERATEDCIRCULATING-FUELREACTOR . . . . . . . . . . . . . . . . . .. ,.. .. .. ... .,...... . . ......... ................... ...................... . .. .. ..... .. .. .. .. .. ..... .. .. .. .. .. .. . . ..................... . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ....................... , , . . . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

Slip rings for temperature ement Rotameter type of flowmeter Handling of Fluorides and Liquid Mek/gls Distillation of NaK Flame tests for NaK vapor in helium

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LIDTANKFACILITY,. . . . . . . . . . . . . . . . . . . . . . . .

Effective Fast-Neutron Removal Cross Sections . . . . e

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BULK SHIELDING FACILITY

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Air-Scattering Experiments Irradiation of Animals Neutron Spectroscopy for the Divided Shield e e Gamma Spectroscopy for the Divided Shield e e e Fission Energy and Power in the Bulk Shielding Reactor

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NUCLEARMEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . .

Fast-Neutron Scintillation Spectrometer . . .

Measurements with 6-Mev Van de Graaff . . . . . . . . . . . . . .

TOWER SHIELDING FACILITY TowerDesign , , , Construction Schedule

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Mockup of the Unit Shield of the Reflector-Moderated Reactor

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SHIELDING RESEARCH

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INTRODUCTION AND SUMMARY

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Staticphysics Reactors with various reflector-moderators Reactors with beryllium reflector-moderators Summary tables and graphs Critical Experiments First critical assembly Second critical assembly Design Characteristics Factors affecting core diameter Temperature, pressure, and s t r ~ s s Reflector heating Shielding e Power Plant Design

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MATERIALS RESEARCH

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INTRODUCTION AND SUMMARY

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KC1-UC1, .

F u e l M i x t u r e s C o n t a i n i n g UF, .ARE. F .u e.l . . .. .. .. .. .. . .

A d d i t i o n of R e d u c i n g Coolant .. . . . . . . . . . . .. .

LiF-ZrF, .. . . . . . * .. .

CsF-ZrF, , . . * . .. . . . ..."

KF-LiF-ZrF,.. . . . . . . . . . .. .

RbF-LiF-ZrF, .. . . ,. , . . . . .

KF-LiF-BeF2 . . . . .. .. . .

P r o d u c t i o n and P u r i f i c a t i o n of F l u o r i d e M i x t u r e s . . .

Laboratory-scale f u e l preparation . . . . . .

Pilot-scale fuel purification . . . . . . . . . . .. . ..

Fluoride production f a c i l i t y . . .

H y d r o f l u o r i n a t i o n of Zr02-NaF m i x t u r e s . ... .. .

CORROSION RESEARCH . . . . .. . . . .... ..

F l u o r i d e C o r r o s i o n o f M e t a l s i n S t a t i c , Seesaw, and .. ... .. ..

Rotating Tests . . .

Crevice corrosion .... . . ... .

High-temperature pretreatment of Inconel .

E f f e c t o f t i m e of e x p o s u r e of I n c o n e l t o f l u o r i d e m i x t u r e w i t h and w i t h o u t ZrH, added .. . ... .

S t r u c t u r a l metal f l u o r i d e a d d i t i v e s , . .. .. . .

Hydrogen f l u o r i d e a d d i t i v e . . . . . . ..

Fluoride corrosion i n rotating rig Static on I n c o l o y and I n c o n e l i n f l u o r i d e s . . . .

F l u o r i d e C o r r o s i o n of M e t a l s Thermal C o n v e c t i o n Loops ..

E f f e c t of f l u o r i d e batch s i z e . . . . . .. .

Fluoride . . . . .

Hydride a d d i t i v e s . . .. . . .. .. .. . .

Metal a d d i t i v e s . ...

Temperature dependence , Crevice corrosion . . .. . . .. . . . .. .. . . . . .

CHEMISTRY OF HIGH-TEMPERATURELIQUIDS F u e l M i x t u r e s C o n t a i n i n g UF, LiF-ZrF,-UF, e KF-LiF-BeF,-UF, e e F u e l M i x t u r e s C o n t a i n i n g ThF, F u e l M i x t u r e s C o n t a i n i n g UC1, NaC1-UC1, e e e ,

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105 107 107 107 107 107 108 109 109 109 110 112 112 112 112 112 113 113 113 114 115 115 117 118 118 118

118 119 120 121 121 121 121 122 123 123 123 124 124

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E f f e c t of e x p o s u r e t i m e * e e e Nonuranium b e a r i n g m i x t u r e s e e e L i q u i d Metal C o r r o s i o n o f S t r u c t u r a l M e t a l s e e Seesaw t e s t s o f s o d i u m - l e a d a l l o y s e e e S t a t i c tests with lithium e e I n c o l o y i n s o d i u m , l i t h i u m , and l e a d e e e C o r r o s i o n by l e a d i n t h e r m a l c o n v e c t i o n l o o p s e e C o r r o s i o n o f C e r a m i c s b y F l u o r i d e s and L i q u i d Metals C e r m e t s i n f l u o r i d e s and l i q u i d m e t a l s e S t a t i c t e s t s of t h e ARE-Be0 b l o c k s i n Na a n d NaK e e Seesaw t e s t s o f B e 0 i n NaK e e e e e e C o n v e c t i o n l o o p t e s t s of Be0 i n NaK e e e e e S o l u b i l i t y o f Be0 i n NaK e e e a e e E f f e c t o f Atmosphere on t h e Mass T r a n s f e r o f Nickel i n Hydroxides e e e e e Fundamental C o r r o s i o n R e s e a r c h e e e e e I d e n t i f i c a t i o n o f c o r r o s i o n p r o d u c t s from c o n v e c t i o n loops e e e P r e p a r a t i o n o f s p e c i a l complex f l u o r i d e s A i r o x i d a t i o n of fuel m i x t u r e s e e e e e

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METALLURGY AND CERAMICS e e e e e e a e e e e Welding and B r a z i n g R e s e a r c h Cone-arc welding e e e e e e e e e e F a b r i c a t i o n of h e a t exchanger u n i t s e e e Brazing of copper t o I n c o n e l e e e e e E v a l u a t i o n Tests of B r a z i n g A l l o y s e e e e C o r r o s i o n of b r a z i n g a l l o y s b y f l u o r i d e s e E f f e c t o f b r a z i n g t i m e on j o i n t s t r e n g t h e e e e E f f e c t o f s p a c i n g on b r a z e d j o i n t s t r e n g t h e e S t r e n g t h of b r a z e d j o i n t s w i t h v a r i o u s b a s e m e t a l s Creep-Rupture T e s t s of S t r u c t u r a l Metals e e e e Preoxidized Inconel i n argon Peened I n c o n e l i n a r g o n e a e e e E f f e c t of I n c o n e l g r a i n s i z e on t i m e t o r u p t u r e e E f f e c t o f e n v i r o n m e n t on s t r a i n vs. t i m e c u r v e s f o r I n c o n e l Type 316 s t a i n l e s s s t e e l t u b e b u r s t t e s t s i n a r g o n e F a b r i c a t i o n of C o n t r o l and S a f e t y Rods e e e e e e , Control -rods f o r t h e Reactor e e Tower s h i e i d i n g f a c i l i t y s a f e t y r o d s e e e 4 Columbium R e q e a r c h Gaseous r e a c t i o n s e e e e e O x i d a t i o n ,' e e e e e e ,, e e F a b r i c a t i o n of Metals e e e e e e e High-conductivity metals f o r r a d i a t o r f i n s S o l i d - p h a s e bonding e e * . e . . * . .

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HEAT TRANSFER AND PHYSICAL PROPERTIES . . . . . . . . .. .

Thermal C o n d u c t i v i t y of L i q u i d s .... ....

Heat C a p a c i t y of L i q u i d s . . . . . . . .. .. . . . . .

V i s c o s i t y and D e n s i t y o f A l k a l i H y d r o x i d e s , .. ..

Vapor P r e s s u r e s of F l u o r i d e s . . , . . . . . .

P r a n d t l Moduli o f V a r i o u s . . . . . .. . .

S p e c i f i c R e a c t o r Heat T r a n s f e r P r o b l e m s .

Turbulent Convection i n . . . . . . .

C i r c u l a t i n g - F u e l Heat T r a n s f e r . . . . .. . . . . .

High T e m p e r a t u r e R e a c t o r C o o l a n t ‘ S t u d i e s .

RADIATIONDAMAGE . . . . . . . . . . .. . .

I r r a d i a t i o n of Fused Materials . . . . .

I n - R e a c t o r C i r c u l a t i n g Loops . . . . . . . .

C r e e p Under I r r a d i a t i o n .. .. .... .. . .. ..

ANALYTICAL STUDIES OF REACTOR MATERIALS . . . . .

Chemical A n a l y s i s of F u e l s and C o n t a m i n a n t s .. . .

Zirconium . . . . . . . . .

Reduction products . . . . . . . . . . ..

Oxides . . . . . . . . . . . .

Hydrogen f l u o r i d e . .. . .. . . . . . .

Corrosion products . . . . .

P r e p a r a t i o n of Uranium T e t r a c h l o r i d e , . . . . . .

P e t r o g r a p h i c Examination of F l u o r i d e s . . .. . . . . . ..

UC14-NaC1 . . . . . .

UCl,-KCl . . . .. . . . .. .. .. . . . . .. . ..

X-Ray D i f f r a c t i o n S t u d i e s .

Service Chemical Analyses . .. ... .... .. , e e e E x t r u s i o n of h i g h - p u r i t y t u b i n g e e H o t - P r e s s e d Pump S e a l s e , e e e . . . e Ceramics e e e e Ceramic c o a t i n g s , f o r s h i e l d i n g Development o f cermet f u e l e l e m e n t s e R e d u c t i o n o f p o r o s i t y o f ARE b e r y l l i u m o x i d e

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APPENDIXES

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PROJECT . . . ...

LIST OF REPORTS ISSUED DURING THE QUARTER

TECHNICAL ORGANIZATION CHAR

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efined i n the Atomic losure of its contents

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A N P PROJ

GRESS REPORT

This q u a r t e r l y progress e A i r c r a f t Nuclear Propulsion P r o j e c t f t h e r e s e a r c h on t h e c i r c u l a t i n g - f u e l a t ORNL r e c o r d s t h e t e c h n i r e a c t o r a n d a l l o t h e r ANP r e s e a r c h a t t h e L a b o r a t o r y u n d e r i t s C o n t r a c t W-7405-eng-26.

The r e p o r t i s d i v i d e d i n t o t h r e e major p a r t s : I. R e a c t o r T h e o r y and D e s i g n , 11. S h i e l d i n g R e s e a r c h , and 111. M a t e r i a l s R e s e a r c h .

Each p a r t h a s a s e p a r a t e i n t r o d u c t i o n and summary.

The ANP P r o j e c t i s c o m p r i s e d o f a b o u t t h r e e h u n d r e d t e c h n i c a l and s c i e n t i f i c p e r s o n n e l e n g a g e d i n many p h a s e s o f r e s e a r c h d i r e c t e d t o w a r d t h e n u c l e a r propulsion of a i r c r a f t .

(The P r o j e c t o r g a n i z a t i o n c h a r t i s i n c l u d e d a s a n a p p e n d i x . ) A c o n s i d e r a b l e p o r t i o n of t h i s r e s e a r c h i s p e r f o r m e d i n s u p p o r t o f t h e work o f o t h e r o r g a n i z a k i o n s p a r t i c i p a t i n g i n t h e n a t i o n a l ANP e f f o r t ; . Howe v e r , t h e b u l k o f t h e ANP r e s e a r c h a t ORNL i s d i r e c t e d t o w a r d t h e d e v e l o p m e n t of a c i r c u l a t i n g - f u e l t y p e o f r e a c t o r .

The n u c l e u s of t h e e f f o r t on c i r c u l a t i n g - f u e l r e a c t o r s i s now c e n t e r e d upon the A i r c r a f t Reactor Experiment - a 3-megawatt, high-temperature p r o t o t y p e of a circulating-fuel reactor for the propulsion of aircraft.

This reactor e x p e r i m e n t i s now b e i n g a s s e m b l e d ; i t s c u r r e n t s t a t u s i s summarized i n s e c . 1.

However, much s u p p o r t i n g r e s e a r c h on m a t e r i a l s and p r o b l e m s p e c u l i a r t o t h e ARE w i l l b e f o u n d i n o t h e r s e c t i o n s of P a r t I and P a r t I11 o f t h i s r e p o r t , a l o n g w i t h t h e g e n e r a l d e s i g n and m a t e r i a l s r e s e a r c h c o n t a i n e d t h e r e i n .

A s u r v e y r e p o r t on a r e f l e c t o r - m o d e r a t e d t y p e o f c i r c u l a t i n g - f u e l r e a c t o r i s c o n t a i n e d i n s e c . 2.

S i n c e t h e f e a s i b i l i t y o f s u c h a r e a c t o r was i n d i c a t e d by c r i t i c a l e x p e r i m e n t s c o m p l e t e d d u r i n g t h e p r e v i o u s q u a r t e r , c o n s i d e r a b l e r e s e a r c h , a s w e l l a s d e s i g n e f f o r t , h a s been devoted t o problems a s s o c i a t e d therewith. +The s h i e l d i n g r e s e a r c h r e p o r t , P a r t 11, i s d e v o t e d a l m o s t e n t i r e l y t o problems of a i r c r a f t s h i e l d i n g .

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INTRODUCTION AND SUMMARY The A i r c r a f t R e a c t o r E x p e r i m e n t ( s e c . 1 ) i s r a p i d l y t a k i n g form a s equipment is r e c e i v e d and i n s t a l l e d i n t h e ARE B u i l d i n g .

There were no significant changes in design o r c o n c e p t d u r i n g t h e q u a r t e r , and t h e i n s t a l l a t i o n i s proceeding according t o schedule.

The f u e l s y s t e m h e a t t r a n s f e r l o o p and t h e f i l l and f l u s h t a n k s a r e c o m p l e t e l y i n s t a l l e d , and the sodium h e a t t r a n s f e r loop is nearing completion.

I n s t a l l a t i o n of f u e l a n d s o d i u m p i p i n g i s now i n progress.

The c o n t r o l and g r a p h i c p a n e l s have been completely i n s t r u mented and checked.

The formal p r e s e n t a t i o n on t h e h a z a r d s i n v o l v e d i n t h e ARE was m a d e t o t h e R e a c t o r S a f e g u a r d s Committee earlier i n t h e q u a r t e r , and i n view o f t h e s u b s e q u e n t d i s c u s s i o n o f t h e C o m m i t t e e members, i t i s n o t e x p e c t e d t h a t any m o d i f i c a t i o n s o f t h e e x p e r i m e n t w i l l be required.

V a l v e s , pumps, i n s t r u m e n t a t i o n , and o t h e r c o m p o n e n t s o f t h e f l u o r i d e f u e l and s o d i u m - c o o l a n t s y s t e m s a r e b e i n g d e v e l o p e d and t e s t e d f o r t h e ARE ( s e c . 2 ) .

B o t h c e n t r i f u g a l and e l e c t r o m a g n e t i c pumps o f ARE c a p a c i t y have been o p e r a t e d ; t h e l a t t e r w i l l be employed i n t h e by-pass l o o p f o r p r e l i m i n a r y t e s t s , w i t h NaK, o f t h e e x t e r n a l f u e l system. I m p e l l e r d e s i g n s f o r t h e c e n t r i f u g a l pumps a r e c o n v e n t i o n a l , b u t t h e pump s e a l , p a r t i c u l a r l y f o r f l u o r i d e f u e l s , remains a problem.

T h e p a c k e d - f r o z e n s e a l s on f u e l pumps h a v e w i d e l y v a r y i n g l e a k a g e r a t e s , and adequate t e m p e r a t u r e c o n t r o l o f t h e f r o z e n zone h a s n o t been obtained.

B o t h p a c k i n g and f a c e - s e a l m a t e r i a l s a r e b e i n g examined i n an effort to find materials with the d e s i r e d s e r v i c e and l i f e c h a r a c t e r i s t i c s . Gas f a c e s e a l s f o r v e r t i c a l s h a f t pumps a r e b e i n g i n v e s t i g a t e d .

C o n s i d e r a b l e s u c c e s s h a s been e x p e r i enced with frozen-sodium s e a l s i n sodium pumps, and f r o z e n - l e a d s e a l s

are being t e s t e d f o r use with fluorides.

Frozen-sodium and f r o z e n - l e a d s e a l s have p r o v e d t o be u n s a t i s f a c t o r y f o r u s e o n NaK p u m p s .

T h e ARE b e l l o w s t y p e o f v a l v e was t e s t e d a t 1 1 0 0 and 1300째F and found t o be s a t i s f a c t o r y , a 1 t h o u g h e x c e s s i v e 1e a k a g e o c c u r r e d a f t e r o p e r a t i o n a t 1500째F. The i n i t i . a l m o c k u p o f t h e ARE f l u i d c i r c u i t r e v e a l e d i n s t a b i l i t i e s and g a s e n t r a i n m e n t t h a t were e l i m i n a t e d by m i n o r system a l t e r a t i o n s .

The r o t a m e t e r s , l e v e l i n d i c a t o r s , and p r e s s u r e t r a n s m i t t e r s have o p e r a t e d s a t i s f a c t o r i l y f o r long p e r i o d s of t i m e under t h e conditions expected i n the Aircraft Reactor Experiment.

The r e a c t o r p h y s i c s s t u d i e s ( s e c .

3 ) were concerned w i t h t h e s t a t i c s of t h e r e f l e c t o r - m o d e r a t e d r e a c t o r and damping o f power o s c i l l a t i o n s .

The a p p l i c a b i l i t y o f t h e m u l t i g r o u p method t o t h e c a l c u l a t i o n of t h e r e f l e c t o r m o d e r a t e d r e a c t o r was d e m o n s t r a t e d b y t h e good c o r r e l a t i o n o b t a i n e d w i t h c r i t i c a l experiments.

The d a m p i n g o f power o s c i l l a t i o n s i n a r e a c t o r i s demonstrated f o r a nonlinear case, w i t h d e l a y e d n e u t r o n s i n c l u d e d , by a s s u m i n g ( 1 ) c o n s t a n t power e x t r a c t i o n o r (2) a special case of cooling with circulating fuel.

The r e f l e c t o r - m o d e r a t e d r e a c t o r and an a i r c r a f t power p l a n t a s s e m b l y employing t h i s r e a c t o r a r e d e s c r i b e d ( s e c . 4). I n g e n e r a l , t h e r e a c t o r c o n s i s t s o f lumped r e g i o n s o f f u e l and m o d e r a t o r o r r e f l e c t o r .

An e s s e n t i a l element i n t h i s reactor is t h e use of a t h i c k b e r y l l i u m r e f l e c t o r t h a t not only contributes t0 neutron economy b u t a l s o c o n s t i t u t e s t h e f i r s t layer of the a i r c r a f t shield.

This r e a c t o r and t h e compact, s p h e r i c a l arrangement p e r m i t r e a l i z a t i o n of what i s p r a c t i c a l l y a u n i t s h i e l d f o r a 200-megawatt r e a c t o r and h e a t exchanger combination t h a t weighs a b o u t 80,000 p o u n d s .

C r i t i c a l experim e n t s o n a mockup o f t h i s r e a c t o r

5

ANP PROJECT QUARTERLY PROGRESS REPORT assembly about 20 vestment external

1

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i n d i c a t e a c r i t i c a l mass o f l b and a t o t a l uranium i n o f 1 0 0 l b when t h e c o m p a c t f u e l system is included.

A p r e l i m i n a r y w e i g h t e s t i m a t e of t h e complete power p l a n t a s s e m b l y , i n c l u d i n g t h e t u r b o j e t s , i s a b o u t 115,000 pounds.

PERIOD ENDING MARCH 10, 1953 1.

CIRCULATING-FUEL AIRCRAFT REACTOR EXPERIMENT

J. H. Buck, R e s e a r c h D i r e c t o r ’ s D i v i s i o n ; E. S. B e t t i s , ANP D i v i s i o n

I

The m a j o r e f f o r t i n t h e ARE p r o j e c t d u r i n g t h e q u a r t e r h a s been i n i n s t a l l a t i o n o f e q u i p m e n t i n B u i l d i n g 7503.

The a r r i v a l o f t h e h e a t e x c h a n g e r s p e r m i t t e d t h e i n i t i a t i o n of a l a r g e amount o f c o n s t r u c t i o n work t h a t h a d been p o s t p o n e d f o r s e v e r a l weeks.

V a l v e s began t o a r r i v e toward t h e end o f t h e q u a r t e r , and work c o u l d p r o c e e d on t h e i n s t a l l a t i o n of t h e main plumbing system.

The i n s t a l l a t i o n o f e q u i p m e n t w i l l n o l o n g e r be d e p e n d e n t upon t h e a r r i v a l of c o m p o n e n t s , The i n s t a l l a t i o n work i s n o t a h e a d o f schedule, but thus f a r it appears t h a t t h e completion g o a l o f J u n e 1953 w i l l b e r e a 1 i zed.

No new t e c h n i c a l c r i s e s h a v e a r i s e n i n the project.

T e s t s of v a l v e s , s e a l s , pumps, e t c . c o n t i n u e ( s e c . 2 ) and, t o d a t e , r e v e a l no insurmountable Seals have operated difficulties. s a t i s f a c t o r i 1y , b u t t h e i r p e r f o rmanc e h a s n o t b e e n s o good a s m i g h t b e wished.

T h e same c o n d i t i o n e x i s t s with respect t o the valve tests, but t h e v a l v e s h a v e b e e n shown t o b e usable.

A1 though d e t a i l i n g of i n s t a l l a t i o n drawings continues t o be a problem, i t has not yet actually retarded the job.

There have been the usual m o d i f i c a t i o n s d i c t a t e d by p r o b l e m s a r i s i n g i n t h e f i e l d , but they have b e e n n o more n u m e r o u s or s e r i o u s t h a n would b e e x p e c t e d i n a s y s t e m o f s u c h c o m p l e x i t y a s t h e ARE.

G. A. C r i s t y i n g and M a i n t e n a n c e s i g n c h a n g e s were made i n t h e f l u i d c i k c u i t . s i n c e it appeared inadvisab long drain l i n e s i n the f u e l c i r c u i t t o s t a n d f u l l of s t a g n a n t f u e l , two v a l v e s were a d d e d t o p e r m i t d r a i n i n g

these long lines so that they w i l l be empty d u r i n g o p e r a t i o n of t h e experiment.

The h e a t d i s p o s a l l o o p s f o r t h e fuel circuit, that is, the fuel-tohelium h e a t exchangers, t h e helium-towater h e a t e x c h a n g e r s , t h e t h e r m a l b a r r i e r s , t h e h e l i u m d u c t s , and t h e h e l i u m b l o w e r s , a r e now c o m p l e t e l y installed.

F i g u r e 1.1 s h o w s t h e s e loops installed i n t h e pit.

Three sections of the fuel pipe, together with annuli, thermocouples, and h e a t e r s ( w h e r e p o s s i b l e 1, h a v e b e e n p r e f a b r i c a t e d and c a n b e w e l d e d i n t o t h e s y s t e m when t h e v a l v e s f o r t h e s e l i n e s a r e ready.

F i g u r e 1 . 2 shows o n e o f t h e s e s e c t i o n s of f u e l p i p e .

A l l t h e f i l l and f l u s h t a n k s h a v e been p u t i n t h e p i t , a n d work h a s b e e n s t a r t e d on i n s t a l l i n g h e a t e r s on these units.

T h e s e t a n k s a r e shown i n F i g . 1.3.

The b y - p a s s , which e n a b l e s t h e system t o be run w i t h o u t t h e r e a c t o r i n the c i r c u i t , h a s been designed.

T h e e l e c t r o m a g n e t i c pump, w h i c h w i l l be i n s t a l l e d i n t h i s by-pass f o r c i r c u l a t i n g l i q u i d metal, h a s been t e s t e d by t h e E x p e r i m e n t a l E n g i n e e r i n g Group ( s e c . 2 ) .

The s u r g e t a n k s h a v e b e e n c o m p l e t e d , and t e s t s o f t h e mockup o f t h e h y d r a u l i c s y s t e m a r e c o n t i n u i n g ( s e c . 2).

The h e l i u m - t o - w a t e r h e a t e x c h a n g e r s for t h e sodium c o o l a n t c i r c u i t h a v e b e e n r e c e i v e d and a r e b e i n g i n s t a l l e d .

The l i q u i d metal-to-helium h e a t exchangers a r e t o be d e l i v e r e d t h e f i r s t week o f March.

STRESS ANALYSIS J . W. Walker

R. L. Maxwell

C o n s u l t a n t s , ANP D i v i s i o n The r e a c t o r by-pass c i r c u i t was checked t o see t h a t previous pres t r e s s i n g c a l c u l a t i o n s would n o t be

7

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n c3

F i g . 1.1.

F u e l System Heat Disposal LOOPS.

P E d I O D ENDING MARCH 1 0 , 1 9 5 3

9

ANP PROJECT QUARTERLY PROGRESS REPORT

10

PERIOD ENDING MARCH 1 0 , 1 9 5 3

r

i n v a l i d a t e d by i t s i n c o r p o r a t i o n i n the circuit.

A r e p o r t on t h e c o m p l e t e analysis of the stre i s being prepared.

A d e s i g n h a s been developed f o r t i n g s t r a i n gages i n the system a t t h e anchor p o i n t s t o check t h e computed stresses.

These gages w i l l be i n s t a prior t o the pres t r e s s i n g , an e magnitude o f t h e p r e s t r e s s i n g f o r c e s w i l l be measured.

The stress f as t h e temperature 1 the a b o v e 200'F be u s a b l e .

t h e g a g e s w i l l no l o n g e r

f the serpentine c o i l s and f i n a l a s s e m b l y . F i g u r e s 1.4, 1 . 5 , a n d 1.6 show t h e ' s t a t u s o f p a r t s of the reactor.

A l l p r e l i m i n a r y work on t h e p r e s s u r e s h e l l h a s b e e n completed.

The c o i l s h a v e been r e c e i v e d a n d s a m p l e c o i l s a r e now b e i n g t e s t welded i n O W L s h o p s .

It i s planned ctor into a test circuit at a t design temperature so t h a t t h e pendently checked allation.

This pretesting of the reactor core w i l l

Pneumatic l i n e s have been r u n t o valves and sensing p o i n t s i n t h e p i t s , b u t a s m a l l a m o u n t ( 2 % ) o f work remains t o be done.

Thermocouple d e s i g n s h a v e b e e n c o m p l e t e d anld o r d e r s have been placed.

Several of t h e thermocouples needed t o a l l o w i n s t a l l a t i o n w o r k t o p r o c e e d h a v e b e e n made by t h e I n s t r u m e n t D e p a r t m e n t .

All i n s t r u m e n t s and a c t u a t o r s h a v e b e e n labeled.

The e n u n c i a t o r p a n e l s h a v e been i n s t a l l e d and c h e c k e d , e x c e p t f o r connection t o the sensing points.

OFF-GAS SYSTEM

There h a s been n o change i n t h e f f - g a s s y s t e m , and i n s t a l l a t i o n i n he b u i l d i n g i s p r a c t i c a l l y completed. he f i n a l design for the shielding of the radiati m o n i t o r s h a s n o t been completed, b u t t h i s s h i e l d i n g w i l l be q u i t e s i m p l e and w i l l be assembled i n t h e f i e l d by u s i n g a s t a c k i n g o f l e a d b r i c k s around t h e m o n i t o r s .

REACTOR CONTROL

The model f i s s i o n chamber f o r u s e a t high temperature has operated a t i s f a c t o r i l y f o r several hundred o u r s a t a t e m p e r a t u r e o f 1400'F. T h i s t e s t h a s proved t h e a c c e p t a b i l i t y o f t h e i n s u l a t o r f o r t h i s chamber.

The l i v e chamber, w i t h a U 2 3 5 s l e e v e , h a s n o t y e t been t e s t e d .

7503, b u t n o been made i n that

simulated valve operation.

t h e assembly.

11

; 1

I

i i

ANP'.-PRO JECT QUARTERLY PROGRESS REPORT

m

a 0

0 4

F

PERIOD ENDING MARCH 1 0 , 1953

Fig.

1.5.

Reactor Pressure Shell.

13

dNV

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 ELECTRICAL SYSTEM

L

T h e e l e c t r i c a l work i s p r o c e e d i n g satisfactorily.

The l a r g e j o b o f completing t h e heater c i r c u i t panels h a s been accomplished.

Heaters a r e b e i n g i n s t a l l e d on t h e f i l l and f l u s h

t a n k s , and l e a d s h a v e been r u n from t h e c o n t r o l p a n e l s t o two o f t h e f i l l and f l u s h t a n k s .

Both m o t o r g e n e r a t o r s e t s h a v e been r e c e i v e d and checked.

I t was f o u n d t h a t t h e s e s e t s r a i s e d t h e n o i s e l e v e l i n t h e basement t p an un t o l e r a b l e l e v e l ; c o n s e q u e n t l y t h e y w i l l be moved o u t o f t h e b u i l d i n g .

15

2. EXPERIMENTAL REACTOR ENGINEERING H. W. S a v a g e , ANP D i v i s i o n T h e work o f t h e p a s t t h r e e m o n t h s on t h e l i q u i d c i r c u i t s o f t h e ARE h a s been devoted t o m i n i m i z i n g c o r r o s i o n t o values a c c e p t a b l e f o r 1000 h r of c o n t i n u o u s or i n termi t t e n t o p e r a t i o n a t elevated temperature, determining and a p p l y i n g a p r o c e s s o f b l e n d i n g f l u o r i d e s f o r t h e ARE t h a t w i l l y i e l d a product with a q u a l i t y equal t o t h a t of t h e m i x t u r e u s e d i n t h e most s a t i s factory corrosion tests, providing pumps f o r t h e c i r c u l a t i o n o f f l u o r i d e s a n d e i t h e r s o d i u m or s o d i u m - p o t a s s i u m a l l o y , d e v e l o p i n g s e a l s f o r t h e pumps t h a t a r e r e l i a b l e f o r 1000 h r o f operation, providing other circuit components, and s t u d y i n g c i r c u i t modifications t h a t w i l l assure acceptab l e and operable f l u i d dynamics.

T h i s workwas c a r r i e d o u t c o o p e r a t i v e l y with the Metallurgy Division, the M a t e r i a l s Chemistry D i v i s i o n , and t h e ARE S e c t i o n o f t h e ANP D i v i s i o n .

Both c e n t r i f u g a l and e l e c t r o m a g n e t i c pumps o f ARE c a p a c i t y 50 t o 1 0 0 gpm have been t e s t e d .

The c o n v e n t i o n a l pump i m p e l l e r s a r e s a t i s factory, but s e a l s f o r mechanical pumps a r e s t i l l a p r o b l e m , A lOO-gpm, a - c , d o u b l e - c e l l , e l e c t r o m a g n e t i c pump h a s p r o v e d t o be e n t i r e l y s a t i s f a c t o r y f o r pumping s o d i u m - p o t a s s i u m a l l o y a t 1500째F, and i t i s b e i n g t e s t e d f o r pumping s o d i u m .

Packings for horizontal-shaft c e n t r i f u g a l pumps h a v e n o t y e t b e e n proved r e l i a b l e .

The most p r o m i s i n g p a c k i n g w a s g r a p h i t e a n d / o r MoS, r e t a i n e d w i t h b r a i d or g r a p h i t e r i n g s , or p o s s i b l y by m a g n e t i c means. L e a k a g e r a t e s have v a r i e d w i d e l y , and f r i c t i o n d e m a n d s , i n some c a s e s , h a v e b e e n excessive.

Thermal c o n t r o l of t h e frozen zone, needed f o r l o w - f r i c t i o n o p e r a t i o n and f o r remotely s t o p p i n g a n d s t a r t i n g t h e pump, h a s n o t y e t been a c h i e v e d .

-

-

-

O i l l u b r i c a t e d , 1ow- t e m p e r a t u r e , f a c e - t y p e , g a s s e a l s h a v e been r e l i a b l y operated for thousands of hours i n h i g h - t e m p e r a t u r e , c e n t r i f u g a l , sumpt y p e pumps, An A R E - s i z e sump pump, similarly sealed, i s undergoing a w a t e r t e s t , and t h e r e have been no major d i f f i c u l t i e s , t o d a t e .

F r o z e n - s o d i u m or f r o z e n - l e a d s e a l s f o r NaK h a v e p r o v e d t o be i m p r a c t i c a l .

Frozen-sodium s e a l s f o r A R E - s i z e sodium pumps ( 2 1 / 2 . - i n . - d i a s h a f t ) a r e now b e i n g t e s t e d , and t h e d i f f i c u l t i e s experienced t o d a t e appear t o have been due t o thermal d i s t o r t i o n s .

Frozen-lead s e a l s have been used s a t i s f a c t o r i l y w i t h f l u o r i d e s , and i n s e v e r a l t e s t s with molten f l u o r i d e i n contact with molten lead, t h e r e has been n o m i x i n g o f t h e f l u o r i d e and t h e lead, High-temperature face s e a l s f o r use w i t h molten f l u o r i d e s a r e being investigated, but data a r e not y e t available.

Other components t h a t have been operated successfully for long periods a r e high-temperature r o t a m e t e r s and high-temperature l i q u i d - l e v e l i n d i c a t o r s ( b o t h t h e r o t a m e t e r s and t h e liquid-level indicators use variableinductance pickups for s i g n a l genera t i o n ) ; t h i n - w a l l e d ( 0 . 005 i n . ) bellows i n p r e s s u r e @ t r a n s m i t t e r si n contact with fluorides; apneumaticallyactuated, bellows-sealed, Stellites e a t e d v a l v e ; and t h e s l i p - r i n g and brush arrangements f o r removal o f t h e thermocouple s i g n a l s used f o r measuring t e m p e r a t u r e s i n moving p a r t s .

A study of the parallel c i r c u i t s a n d t h e pumping and e x p a n s i o n t a n k a r r a n g e m e n t s o f t h e ARE h a s r e v e a l e d o p e r a t i o n a l s t e p s t h a t w i l l h a v e t o be t a k e n i n t h e e v e n t o f f a i l u r e o f one o f t h e pumps s o t h a t l o s s o f c i r c u l a t i o n f r o m t h e r e m a i n i n g pump a n d e x p a n s i o n t a n k c a n be p r e v e n t e d .

The

17

ANP PROJECT QUARTERLY PROGRESS dEPORT study a l s o revealed t h e need f o r p i p i n g modifications t o e l i m i n a t e gas entrainment a t the free surface i n t h e surge tanks.

Sodium-potassium a l l o y h a s been d i s t i l l e d from c l o s e d s y s t e m s t o s i m u l a t e c i r c u i t c l e a n i n g o f t h e ARE; n e g l i g i b l e q u a n t i t i e s of a l l o y remained i n i s o l a t e d pockets.

PUMPS W. B. W. G. W. R. J . M.

FOR HIGH-TEMPERATURE LIQUIDS McDonald A. G. G r i n d e l l Cobb G. D. Whitman A . L. S o u t h e r n Huntley P. W. T a y l o r Trummel ANP D i v i s i o n

Centrifugal P u m p w i t h C o m b i n a t i o n Packed and Frozen Seal for Fluorides.

A 50-gpm pump w i t h a S t e l l i t e No. 6 coated, 2 1/2-in.-dia s h a f t was o p e r a t e d f o r 85 h r w i t h t h e ARE f u e l , NaF-ZrF4-UF, ( 5 0 - 4 6 - 4 mole % ) .

The s e a l c o n s i s t e d of a packing of 1/4-by 1 / 4 - i n . monel b r a i d w r a p p e d i n n i c k e l f o i l , O p e r a t i o n was u n s a t i s f a c t o r y and t h e t e s t was t e r m i n a t e d b e c a u s e o f s h a f t seizure i n the packing area.

Examination of t h e s h a f t a f t e r t h e run showed t h a t v e r y s e v e r e s c o r i n g h a d o c c u r r e d , Some g r o o v e s were 0 . 0 4 9 i n . deep.

I t may be c o n c l u d e d from t h i s t e s t t h a t small packings alone are inadequate.

Compressive l o a d i n g t o m i n i m i z e l e a k a g e w i l l be h i g h and w i l l r e s u l t i n e x c e s s i v e wear because t h e poor p e n e t r a t i o n of l i q u i d f l u o r i d e s w i l l prevent t h e i r a c t i n g a s a s o r t of l u b r i c a n t . The p a c k i n g i n s u b s e q u e n t t e s t s i n c l u d e d b r a i d a s a component a n d e i t h e r g r a p h i t e o r MoSz, e a c h o f which i s a l u b r i c a n t .

T h e pump h a s b e e n r e p a c k e d w i t h Dixon's Microfyne flake-graphi te p o w d e r , , w h i c h i s r e t a i n e d by c l o s e f i t t i n g , s o l i d , APC-graphite r i n g s a t e a c h end o f t h e p a c k i n g g l a n d . I n i t i a l dry runs, without fluorides present, showed t h i s p a c k i n g t o be q u i t e s e n s i t i v e t o compressive loading.

A p p r o x i m a t e l y 35 p s i was f o u n d t o be a

18

maximum p a c k i n g l o a d i n g f o r s m o o t h , dry operation without the s e a l heating excessively.

T h e r e p a c k e d pump h a s now o p e r a t e d a t a s h a f t s p e e d o f 7 0 0 rpm f o r 300 h r a t 1200OF. The p r e s s u r e a g a i n s t t h e s e a l h a s been v a r i e d from 5 t o 18 p s i . L e a k a g e o f s o l i d f u e l from t h e s e a l h a s v a r i e d from 6 0 t o 75 g/day d u r i n g o p e r a t i o n w i t h p r e s s u r e s i n t h e 5- t o 1 0 - p s i r a n g e .

Power i n p u t to t h e d r i v i n g motor has been q u i t e smooth, w i t h a v a r i a t i o n from 2 . 6 t o 3 . 0 kw, a n d u n d e r t h e s e c o n d i t i o n s o n l y 1 . 5 t o 1 . 8 kw i s b e i n g l o s t a s f r i c t i o n i n t h e pump s e a l .

Allis-Chalmers Centrifugal Pump for The A l l i s - C h a l m e r s L i q u i d Metals. h y d r o s t a t i c - b e a r i n g pump p r e v i o u s l y r e p o r t e d ( ' ) was s h u t down d u r i n g t h e quarter for alterations.

A new, o n e p i e c e s h a f t h a s been f a b r i c a t e d , t h e b e a r i n g s u r f a c e on t h e i m p e l l e r h a s been h a r d c o a t e d w i t h S t e l l i t e , and a frozen-sodium gas s e a l h a s been i n c o r p o r a t e d i n t h e pump.

A l l fabric a t i o n i s c o m p l e t e a n d t h e pump i s ready f o r reassembly and f u r t h e r testing.

Laboratory-Size Pump with Gas Seal.

The l a b o r a t o r y - s i z e g a s - s e a l e d c e n t r i f u g a l pump o p e r a t e d 9 9 6 h r w i t h f l u o r i d e f u e l , NaF-ZrF4-UF, ( 4 6 - 5 0 - 4 mole % ) , a t a t e m p e r a t u r e o f 1500째F. The pump h a s t h u s f a r o p e r a t e d a t o t a l o f 2300 h o u r s .

T h e pump w a s r u n a t 3 6 0 0 rpm a n d p r o d u c e d a 5 0 - p s i h e a d a t 8 t o 1 0 gpm.

F i g u r e 2 . 1 shows t h e u p p e r a s s e m b l y o f t h e pump a f t e r 996 h r o f o p e r a t i o n .

T h e ZrF, c o n d e n s a t i o n d o e s n o t a p p e a r t o be e x c e s s i v e ; h o w e v e r , i n t h e o r i g i n a l a s s e m b l y , p r o b e s h o r t i n g was s e r i o u s and t h e two p r o b e s i n t h e pump were r e n d e r e d i n o p e r a b l e a f t e r 5 0 h r of operation.

T h e s h o r t i n g may h a v e been a r e s u l t of f u e l f r e e z i n g around a n d b r i d g i n g t h e p r o b e and r a d i a t i o n s h i e l d a s s e m b l y , shown i n F i g . 2 . 1 , when an i n a d v e r t e n t l i q u i d - l e v e l s u r g e ("ANP Q u u r . Prog. R e p . D e c . 1 0 , 1 9 5 2 , ORNL1439, p . 19.

PERIOD ENDING MARCH 10, 1953

J

Fig.

2.1.

Gas-Seal Pump Assembly After Operation.

19

ANP PROJECT QUARTERLY PROGRESS REPORT occurred during operation or f i l l i n g , T h i s c o n d i t i o n h a s b e e n a l l e v i a t e d by i n c r e a s i n g t h e c l e a r a n c e between t h e p r o b e s and r a d i a t i o n b a f f l e s a n d i n s e r t i n g a h a l f c y l i n d e r i n t h e cutaway s e c t i o n i n t h e b a f f l e assembly.

T h e pump o p e r a t e d q u i t e s a t i s f a c t o r i l y w i t h o u t p r o b e s , and t h e v e l i n t h e pump b o w l w a s d by n o t i n g t h e pump p e r and t e m p e r a t u r e of t h e face plate.

The r e a s o n f o r termin a t i o n was a g a i n a b r o k e n q u i d e v a n e in d i s c h a r g e bowl. The v a n e s h a v e be t o t h e bowl s e v e r a l times, bu f a i l u r e occurred i n the pa f t h e vane r a t h e r than i n t h e weld.

The r e l i a b i l i t y o f t h i s t l y i n c r e a s e d bv employing t h i c k e r vanes and a d d i n g a r e i n f o r c i n g r i n g around t h e t o p edge o f t h e s i x vanes.

An i d e n t i c a l pump h a s b e e n i n s t a l l e d and h a s o p e r a t e d a p p r o x i m a t e l y 700 h r i n a f l u o r i d e system t h a t i n cludes a fluoride-to-NaK h e a t exchanger.

S e v e r a l d e s i g n c h a n g e s w e r e made t o reduce or nearly eliminate the o i l leakage p a s t the r o t a r y gas s e a l .

I t was f o u n d t h a t when t h e g a s volume a b o v e t h e pump was v e n t e d i n t o a s i g h t g l a s s , the discharged helium was h e a v i l y l a d e n w i t h o i l vapor.

It h a s n o t been a s c e r t a i n e d w h e t h e r t h i s vapor is harmful t o f l u o r i d e s , b u t , a t l e a s t , t h e c o n t a m i n a t i o n was u n desirable, I n t h e o r i g i n a l pump, o i l was u s e d t o c o o l t h e d r i l l e d s h a f t and t o f l o o d t h e r o t a r y gas s e a l assembly both f o r c o o l i n g and f o r l u b r i c a t i o n .

In the p r e s e n t pump, t h e s h a f t a n d t h e s t a t i o n a r y s e a l r i n g are water cooled by u s i n g a c l o s e d s y s t e m . The r o t a r y f a c e s e a l c a n be l u b r i c a t e d , i f n e c e s s a r y , by a d d i n g s m a l l a m o u n t s o f o i l , a s l i q u i d or m i s t , t h r o u g h a n opening i n the bearing housing.

The r o t a r y , G r a p h i t a r No. 3 0 , g a s s e a l i n g r i n g was r e p l a c e d w i t h a s i l v e r i m p r e g n a t e d g r a p h i t e (Mor g a n i t e MYIF) r i n g , and an a t t e m p t was made t o

-

20

run t h e dry s e a l a g a i n s t hardened t o o l s t e e l . However, a t a b e a r i n g p r e s s u r e o f approximately 60 p s i , t h i s combin a t i o n would n o t r u n u n l u b r i c a t e d .

It h a s been n e c e s s a r y t o a d d s m a l l amounts of o i l t o reduce gas leakage and t o p r e v e n t s m a l l power e x c u r s i o n s i n t h e r e c o r d e d demand o f t h e pump m o t o r . The s e a l has required an average of 6 t o 8 drops o f o i l p e r day, and t h e gas l e a k a g e h a s been n e g l i g i b l e .

It is planned t o use a Keller A i r Line l u b r i c a t o r t o atomize the l u b r i cation i n t o the s e a l region through t h e b e a r i n g h o u s i n g . T h i s u n i t may be operated remotely as frequently a s experience d i c t a t e s .

ARE-Size Sump Pump. A m o d i f i c a t i o n h a s been made t o t h e e x i s t i n g model DA p u m p ( 2 ) t o c o n v e r t i t t o a sump pump w i t h a s h a f t l a b y r i n t h s e a l from w h i c h l e a k a g e w i l l r e t u r n by g r a v i t y t o t h e pump’s sump t a n k .

T h e m o d i f i e d pump i s now b e i n g t e s t e d w i t h w a t e r a n d o t h e r r o o m - t e m p e r a t u r e l i q u i d s , and i t w i l l be t e s t e d w i t h l i q u i d s t h a t s i m u l a t e t h e d e n s i t y and v i s c o s i t y of t h e ARE f u e l .

S t u d i e s a r e b e i n g made o f t h e l a b y r i n t h s e a l d u r i n g pump o p e r a t i o n , t h e e f f e c t s o f t h e pump i n l e t s u c t i o n b e l l , and t h e volume o f f l u i d and t h e b a f f l i n g r e q u i r e d i n t h e s u m p t a n k f o r s a t i s f a c t o r y pump operation.

The o p e r a t i o n o f t h e l a b y r i n t h s e a l ( 0 . 0 0 9 - i n . r a d i a l c l e a r a n c e ) was i n v e s t i g a t e d by m e a s u r i n g t h e l e a k a g e o f t h e s e a l a t v a r i o u s pump s p e e d s and heads.

As expected, the fountain i n c r e a s e s w i t h i n c r e a s e i n pump s p e e d and i n pump h e a d . However, t h e amount o f t h e bypass f o u n t a i n flow v a r i e d from 2 t o 10% o f pump f l o w , w h i c h i s a r e a s o n a b l e f r a c t i o n , A minor problem was e n c o u n t e r e d i n t h a t t h e l a b y r i n t h leakage splashed the surface of the l i q u i d i n t h e sump t a n k a n d some o f t h e g a s b u b b l e s were c a r r i e d d e e p e n o u g h t o be e n t r a i n e d i n t h e f l u i d entering the impeller.

(2)W. G . C o b b . A . G . G r i n d e l l , a n d G . D. Whitman, ANP Q u a r . P r o g . R e p . S e p t . 1 0 , 1 9 5 2 , ORNL-1375, p . 17.

t

PERIOD ENDING MARCH 1 0 , 1 9 5 3 T h e pump h a s b e e n t e s t e d i n t w o t y p e s o f sump t a n k .

The f i r s t t a n k was a r e c t a n g u l a r , p l e x i g l a s b o x , 1 4 by 1 6 by 3 0 i n . , i n w h i c h t h e f l u i d i n l e t t o t h e t a n k was c o n s i d e r a b l y o f f s e t from t h e e y e o f t h e i m p e l l e r .

The s e c o n d t a n k was a p l e x i g l a s c y l i n d e r , a b o u t 12 i n . i n d i a m e t e r and 14 i n . h i g h , i n which t h e f l u i d i n l e t i s below and d i r e c t l y i n t o eye of t h e impe 1l e r When c o n t i n u o u s l y submerged , e v e n i f o n l y t o a s m a l l f r a c t i o n o f an i n c h , t h e pump i n l e t s u c t i o n b e l l appeared t o function s a t i s f a c t o r i l y i n e i t h e r sump t a n k u n d e r a l l c o n d i t i o n s o f pump s p e e d and f l o w , Pump p r i m i n g i s n o t d i f f i c u l t t o accomplish i n e i t h e r tank.

In the i n i t i a l t e s t s e t u p , t h e volume o f g a s i n t h e s y s t e m p i p i n g a t s t a r t u p was a p p r o x i m a t e l y e q u a l t o t h e volume o f l i q u i d ; and i n t h e c y l i n d r i c a l t a n k , t h e p r i m e was b r o k e n by a s u d d e n s u r g e o f gas i n t o t h e impeller eye.

Placing an obstruction over the f l u i d i n l e t t o d i v e r t m o s t o f t h e g a s b u b b l e s away f r o m t h e e y e t o t h e f r e e s u r f a c e was s u f f i c i e n t t o maintain t h e prime.

In a system i n which t h e r e i s a s m a l l g a s volume compared w i t h t h e l i q u i d volume a t s t a r t u p , p r i m i n g i s a c c o m p l i s h e d by b l e e d i n g t h e t r a p p e d g a s i n t o t h e sump t a n k o r by f i l l i n g u n d e r vacuum.

In t h e ARE s y s t e m , t h e t r a p p e d g a s i s forced out.

T e s t s w e r e made i n w h i c h t h e f l u i d was g a s s e d by a d m i t t i n g a i r , h e l i u m , or argon i n t o t h e eye o f t h e s u c t i o n b e l l u n t i l t h e f l u i d became m i l k y .

The time r e q u i r e d f o r t h e f l u i d t o become r e l a t i v e l y c l e a r was t h e n noted, In a l l tests, including tests w i t h f l o w r a t e s o f u p t o 1 0 0 gpm a n d t e s t s i n which t h e c y l i n d r i c a l t a n k w i t h o u t b a f f l e s was u s e d , t h e f l u i d d e g a s s e d i n l e s s t h a n 5 min o f o p e r a t i o n .

When t h e i n l e t o f t h e c y l i n d r i c a l tank. was o f f s e t a b o u t 1 / 2 i n . w i t h r e s p t o eye of the impeller, the e n t i r e h o l d u p volume of l i q u i d i n t h e t a n k was g i v e n a r o t a r y m o t i o n t h a t i n creased i n velocity a t high impeller

.

s p e e d s a n d low f l o w r a t e s .

When t h e b a f f l e s were i n p l a c e , t h i s c i r c u l a r motion o c c a s i o n a l l y caused t h e f o r m a t i o n o f v o r t e x e s and g a s e n t r a i n m e n t i n the l i q u i d . Without b a f f l e s i n t h e c y l i n d r i c a l tank, t h e r o t a r y motion was p r e s e n t b u t n o v o r t e x e s were observed.

The g a s s e a l f o r t h i s pump w i l l be e i t h e r a f r o z e n - s o d i u m o r frozen-lead s e a l o r a mechanical face seal.

ARE Centrifugal Pump. An ARE model FP p u m p ( 3 ) h a s b e e n c o n s t r u c t e d a n d i n c o r p o r a t e d i n a t e s t l o o p . The most c r i t i c a l f e a t u r e o f t h i s pump was t h e frozen-sodium s e a l f o r which sodium f r o m a n e x t e r n a l s o u r c e was f e d t o a s e a l i n g a n n u l u s and f r o z e n i n r i n g s on each s i d e of t h e annulus, T h r e e t e s t s h a v e been r u n i n w h i c h NaK was pumped f o r a b o u t 15 min, 4 h r , and 1 h o u r .

E a c h t e s t was t e r m i n a t e d because of excessive s e a l leakage.

Chemical a n a l y s e s o f s a m p l e s of l e a k a g e material indicated the presence of from 1 t o 7 . 5 % p o t a s s i u m .

Since this pump d o e s n o t o p e r a t e s u c c e s s f u l l y w i t h NaK, i t was m o d i f i e d f o r t e s t i n g w i t h sodium. For o p e r a t i o n w i t h s o d i u m , t h e e x t e r n a l s u p p l y o f sodium t o t h e s e a l w i l l n o t be n e e d e d and a l a r g e r s u r f a c e w i l l be p r e s e n t e d f o r c o o l i n g of t h e s e a l .

P r i o r t o i n s t a l l a t i o n o f t h e new s e a l i n g gland,

a series of

tests w a s

r u n on t h e e x t e r n a l l y s u p p l i e d s e a l w i t h h e l i u m i n t h e pump l o o p .

During t h e s e t e s t s , pump s p e e d s a n d s e a l t e m p e r a t u r e s were s y s t e m a t i c a l l y v a r i e d , and c o n s i d e r a b l e d a t a were t a k e n t o p r o v i d e more a d e q u a t e u n d e r s t a n d i n g o f t h e f r o z e n - s e a l mechanism, Successful operation, as a gas s e a l , was o b t a i n e d o v e r t h e a v a i l a b l e r a n g e o f s p e e d s , 400 t o 1920 rpm, and t h e t e m p e r a t u r e o f t h e sodium i n t h e g l a n d g r o o v e v a r i e d from 300 t o 400'F. S p e e d and p r e s s u r e c o n d i t i o n s were d e t e r m i n e d u n d e r which t h e s e a l would f a i l and u n d e r which i t would o p e r a t e r e l i a b l y , (3)ANP Quar. P r o g . R e p . D e c .

1 0 , 1 9 5 2 , ORNL-

1439, p . 21.

21

A N P PROJECT QUARTERLY PROGRESS REPORT The s e a l i n g g l a n d t h a t h a s b e e n i n s t a l l e d i n t h e pump f o r o p e r a t i o n w i t h sodium h a s a l e n g t h - t o - d i a m e t e r r a t i o o f 2.3, i n c o n t r a s t t o the r a t i o s o f 0 . 6 and 0.2 f o r t h e i n s i d e and o u t s i d e g l a n d s o f t h e p r e v i o u s l y used e x t e r n a l l y supplied seal. Also, the radial shaft- to-gland clearance h a s been i n c r e a s e d f r o m 0 . 0 1 5 i n . f o r the externally supplied gland to 0.030 i n . f o r t h e l o n g e r g l a n d .

Initial t e s t s o f t h i s g l a n d and s e a l i n d i c a t e a satisfactory s e a l , but they a l s o i n d i c a t e the presence of excessive thermal d i s t o r t i o n s t h a t w i l l r e s u l t i n d i s p l a c e m e n t o f p a r t s and e v e n t u a l binding.

Electromagnetic Pump. The twos t a g e e l e c t r o m a g n e t i c pump t h a t w i l l b e u s e d t o c i r c u l a t e NaK i n t e s t i n g and c l e a n i n g o p e r a t i o n s o f t h e f u e l c i r c u i t o f t h e ARE h a s b e e n t e s t e d w i t h NaK a t 1 5 0 0 째 F and i s u n d e r g o i n g s i m i l a r t e s t s w i t h sodium.

W i t h NaK, t h e pump d e l i v e r y i s a p p r o x i m a t e l y 9 0 gpm a t a p p r o x i m a t e l y 1 0 p s i ; p e r formance c u r v e s a r e shown i n F i g . 2.2.

The pump h a s g i v e n e n t i r e l y s a t i s f a c t o r y performance, except for a hard-soldered j o i n t failure in the current loop, w h i c h was e a s i l y r e p a i r e d , and e x c e s s c o o l i n g , which was removed,

ROTATING-SHAFT AND VALVE-STEM-SEAL DEVELOPMENT

W. B. McDonald R . N . Mason W . C. T u n n e l 1 P. G. S m i t h W. R . H u n t l e y

ANP D i v i s i o n R . E. E n g b e r g Long Range R e a c t o r P l a n n i n g G r o u p

Mechanical Face Seals.

Hightemperature mechanical face s e a l s f o r l i q u i d s such a s f l u o r i d e s a r e being investigated. Successful operation of s u c h s e a l s may be d e p e n d e n t upon d r y f i l m l u b r i c a t i on, b o u n d a r y 1u b r i c a t i o n , or a d s o r b e d - f i l m l u b r i c a t i o n , b u t research has revealed only empirical

22

knowledge a b o u t t h e p r i n c i p l e s o f s i m i l a r s e a l s s u c c e s s f u l l y used i n a p p l i c a t i o n s much l e s s s e v e r e t h a n t h o s e i m p o s e d by ANP r e q u i r e m e n t s .

The p r o b l e m a p p e a r s t o be o n e o f selecting appropriate materials that w i l l retain optically f l a t surfaces a t h i g h t e m p e r a t u r e s and w i l l have t h e p r o p e r d e g r e e o f h a r d n e s s and s o f t n e s s r e l a t i v e t o each other.

Graphite is being considered f o r the s o f t m a t e r i a l and m a t e r i a l s s u c h a s t u n g s t e n c a r b i d e , t i t a n i u m c a r b i d e , and c e r m e t s a r e b e i n g c o n s i d e r e d for t h e h a r d m a t e r i a l .

The methods o f f a b r i c a t i o n and t h e maintenance o f high ambient temperat u r e s and l o w t h e r m a l g r a d i e n t s t o avoid d i s t o r t i o n s a r e also p e r t i n e n t problems.

The w o r k o f o t h e r s h a s shown t h a t factor i n determining w e a r a n d s u r f a c e damage i n s l i d i n g i s t h e t e n d e n c y o f t h e s l i d i n g or r u b b i n g materials to alloy.

Although other f a c t o r s , such a s t h e hardnesses of t h e materials, the melting points, the r u b b i n g v e l o c i t y , and t h e t e m p e r a t u r e of operation, are considered a s being o f s e c o n d a r y i m p o r t a n c e , i n some i n s t a n c e s t h e y may become o f c o n t r o l l i n g i m p o r t a n c e , The u s e o f MoS, a s a h i g h temperature lubricant is intriguing, and c o n s i d e r a b l e work h a s been d o n e t o o b t a i n s u r f a c e s c o a t e d or i m p r e g n a t e d with t h i s material.

Table 2.1 l i s t s t h e a t t e m p t s t o e s t a b l i s h a MoS, l a y e r by a d d i n g MoS, t o t h e v e h i c l e t o make a paste.

I t s h o u l d be n o t e d t h a t MoS, w i l l b e g i n t o o x i d i z e a t a b o u t 700째F i n a i r , b u t i n t h e a b s e n c e o f oxyge-n i t i s s t a b l e t o 2000'F. T e s t s of f a c e s e a l m a t e r i a l s , made by r o t a t i n g them i n c o n t a c t w i t h t h e o t h e r specimen a r e d e s c r i b e d i n T a b l e 2.2. The c h a t t e r i n g n o t e d may h a v e b e e n d u e t o f o r c e s r e s u l t i n g from t h e geometry used i n t h e t e s t apparatus. These experiments i n d i c a t e t h a t of t h e m a t e r i a l s t e s t e d , g r a p h i t e i s b e s t f o r one of t h e m a t e r i a l s , under t h e s e test c o n d i t i o n s , when a i r i s p r e s e n t . a principal

i

I

I

I

PERIOD ENDING MARCH 1 0 , 1 9 5 3

UNCLASSIFIED

'

3

UNCLASSIFIED DWG. 18712

I

I

INPUT VOLTAGE TO CURRENT LOOP

t

0 0

A

25 50 75

A

io0

I 125

0 450

0 x

175

200

EUTECTIC NaK LOOP AT 1500'F

a

3 v)

W v)

a a

-0

?4

0

IO

20

30

40

50

60

70

80

90

FLOW (gPm)

F i g . 2 . 2 . Performance Curves for Double-Stage Electromagnetic Pump w i t h NaK. I n p u t v o l t a g e t o magnet l o o p , 1 2 5 v o l t s .

23

A N P PROJECT QUARTERLY PROGRESS REPORT TABLE 2.1. DESCRIPTION OF ATTEMPTS TO OBTAIN A MoS, SURFACE BASE METAL

REMARKS

TREATMENT AND APPLICATION

VEHICLE

1.

Type 316 stainless steel

G-E enamel

Brushed on, a i r d r i e d , ' f u r n a c e h e a t e d t o 700 F

Good c o a t i n g o b t a i n e d , apparently

2.

Type 316 stainless steel

Brushed on, a i r d r i e d , f u r n a c e h e a t e d t o 700'F

Did n o t s t i c k t o b a s e m e t a l

3.

Type 316 stainless steel

Co 11o i d a1 silver Hightemperature varnish

Brushed on, a i r d r i e d , f u r n a c e h e a t e d t o 700'F

Varnishburnt off, did not stick

4.

Type 316 stainless steel

No.

B r u s h e d on, a i r d r i e d , f u r n a c e h e a t e d t o 700'F

Varnish burnt o f f , d i d n o t s t i c k

5.

Type 316 stainless steel

Keystone g r e a s e

B a s e m e t a l h e a t e d t o 700째F, p a s t e b r u s h e d on

Did n o t s t i c k t o b a s e m e t a l

6.

Type 316 stainless steel

P e r m a t e x No.

Base m e t a l h e a t e d t o 700째F, p a s t e b r u s h e d on

Showed p r o m i s e , f a i r c o a t i n g obtained

7.

Type 316 stainless steel

Ruby f l u x

Base m e t a l h e a t e d t o 700'F, p a s t e b r u s h e d on

Showed p r o m i s e , obtained

8.

Type 316 stainless steel

Aquadag No.

Base m e t a l h e a t e d t o 7OO0F, p a s t e b r u s h e d on

Did n o t s t i c k t o b a s e m e t a l

9.

Type 316 stainless steel

P e r m a t e x No. 2 thinned with Seb a c a t e

Base m e t a l h e a t e d t o 700째F, p a s t e b r u s h e d on

Remained s o f t , p o s s i b l y n o t enough h e a t , i n d i c a t e s p r o m i s e

10.

Lapped t u n g s t e n carbide

None

H e a t e d t o 700'F, d r y MoS2

d i p p e d in

Thin l a y e r o b t a i n e d , a p p a r e n t l y

11.

Etched t u n g s t e n carbide

None

H e a t e d t o 700째F, s p r i n k l e d on

d r y MoS2

Thin l a y e r o b t a i n e d , a p p a r e n t l y

12.

Type 316 stainless steel

None

H e a t e d t o 700'F, d r y MoS2

dipped i n

Good l a y e r o b t a i n e d

13.

Tungsten c a r b i d e

Handi f 1ux

Paste spplied, heated with torch

Adhered t o b a s e m e t a l , b u t uneven

14.

Tungsten c a r b i d e

Ruby f l u x

P a s t e applied, heated with torch

S o f t and f l e x i b l e ,

15.

Type 316 s t a i n l e s s steel

P e r m a t e x No. 2 with Sehacate

Base m e t a l h e a t e d , b r u s h e d on i n f u r n a c e

Good l a y e r ,

16.

Brass

Handi- f l u x

B r u s h e d on b a s e m e t a l , heated i n furnace

Brass burnt, but apparently some l a y e r r e m a i n e d

17.

Type 316 stainless steel

Corn s y r u p

Brushed on b a s e m e t a l , heated i n furnace

F a i r c o a t i n g , shows p r o m i s e

18.

Type 316 stainless steel

Celluf lux

B r u s h e d on b a s e m e t a l , heated i n furnace

Good c o a t i n g , b u t u n e v e n , shows p r o m i s e

19.

Type 316 s t a i n l e s s steel

Pliobond

B r u s h e d on b a s e m e t a l , heated i n furnace

F a i r c o a t i n g , h a r d and brittle

1202 v a r n i s h

2

200

-

An a t t e m p t h a s b e e n made t o e s t a b l i s h an u p p e r t e m p e r a t u r e l i m i t f o r s i l v e r impregnated graphite rubbing a g a i n s t t y p e 316 s t a i n l e s s s t e e l . The a s s e m b l y c e a s e d t o s e a l helium a t a b o u t 450"F, and a l t h o u g h t h e t e m p e r a t u r e was i n c r e a s e d s l o w l y t o 91O0F, s e a l i n g d i d n o t o c c u r a g a i n . When t h e t e m p e r a t u r e was d e c r e a s e d t o 45OoF, s e a l i n g was

24

f a i r coating

apparently

apparently

again accomplished.

This experiment w i l l be c o n t i n u e d , and v a r i o u s s e a l i n g p r e s s u r e s w i l l be t r i e d .

Another experiment i s i n p r o g r e s s i n w h i c h an a t t e m p t i s b e i n g made t o seal against water with silveri m p r e g n a t e d g r a p h i t e v s . t y p e 316 s t a i n l e s s s t e e l a t various d i f f e r e n t i a l p r e s s u r e s and b e a r i n g p r e s s u r e s .

To

PERIOD ENDING MARCH 1 0 , 1 9 5 3 TABLE 2.2.

BASE METAL NO. ( c f . , Table 2.1)

SUMMARY OF TESTS OF FACE SEAL MATERIALS RESULTS

MATERIALS

11

E t c h e d t u n g s t e n c a r b i d e vs. t y p e 316 s t a i n l e s s s t e e l

Operated f o r 2 h r before c h a t t e r i n g occurred

10

Lapped t u n g s t e n c a r b i d e v s . t y p e 316 s t a i n l e s s s t e e l

Operated f o r 2 h r before c h a t t e r i n g occurred

13

T u n g s t e n c a r b i d e vs. t u n g s t e i carbide

Operated f o r only

16

B r a s s vs. t u n g s t e n c a r b i d e

Operated f o r 5 h r before c h a t t e r i n g occurred

12

Type 316 s t a i n l e s s s t e e l v s . tungsten carbide

Operated f o r 3 h r before c h a t t e r i n g o c c u r r e d ; a d d i t i o n o f d r y MoS, s t o p p e d c h a t t e r i n g f o r a b o u t 15 min

14

T u n g s t e n c a r b i d e vs. t y p e 316 s t a i n l e s s s t e e l

O p e r a t e d f o r 7 min b e f o r e c h a t t e r i n g occur red

15

Type 316 s t a i n l e s s s t e e l vs. tungsten carbide

O p e r a t e d f o r 50 min b e f o r e c h a t t e r i n g occurred

C-18 g r a p h i t e v s . t u n g s t e n carbide

Chattered immediately, s u r f a c e n o t f l a t

G r a p h i t e (No. 40) i m p r e g n a t e , w i t h MoS, v s . t u n g s t e n carbide

O p e r a t e d f o r 12 h r a t s e l f - g e n e r a t e d t e m p e r a t u r e o f 225'F

APC g r a p h i t e v s . t u n g s t e n

Attempted t o c o a t g r a p h i t e w i t h f u e l 27, o p e r a t e d f o r 4 h o u r s

C-18 g r a p h i t e vs. t u n g s t e n carbide

H e a t e d w i t h t o r c h t o 475'F, developed

C- 18 g r a p h i t e v s . t u n g s t e n carbide

Dry MoS, a d d e d , h e a t e d t o 913'F w i t h t o r c h , o p e r a t i o n smooth, e x c e p t between 400 and 450째F, when c h a t t e r i n g occurred

d a t e , t h e s e a l h a s n o t been c o n s i s t e n t ; i t h a s l e a k e d a t times and i n v a r y i n g amounts.

O t h e r m a t e r i a l s h a v e been o r d e r e d , s u c h a s b o r o n n i t r i d e c o m p a c t s , MoS,impregnated copper, s i l v e r and s t a i n l e s s s t e e l compacts, and a s i n t e r e d molybdenum c o m p a c t , t h a t w i l l be t r e a t e d t o form a MoSz s u r f a c e .

Combination Packed and Frozen Seal w i t h MoS,.

B e c a u s e MoS, h a s h i g h temperature l u b r i c a t i n g properties, a n a t t e m p t w a s made t o u s e i t a s a

a

short period

chatter

high- temperature packing m a t e r i a l f o r sealing fluorides; fluoride leakage was s l i g h t ; o p e r a t i o n was s m o o t h ; a n d t h e r e were n o power s u r g e s .

However, a s i n p r e v i o u s e x p e r i m e n t s , t h e MoSz was t o o f l u i d a n d c o u l d n o t b e c o n tained.

The r e t a i n e r s u s e d were G r a p h i t a r No. 14 r i n g s , The m a t e r i a l s l o w l y l e a k e d o u t o f t h e s t u f f i n g box and around t h e gland u n t i l t h e gland was c o m p l e t e l y i n s e r t e d .

For t h e n e x t a t t e m p t t o s e a l w i t h t h i s material, a packing of Inconel

25

ANP PROJECT QUARTERLY PROGRESS REPORT b r a i d i m p r e g n a t e d w i t h MoSz was u s e d .

T h i s e x p e r i m e n t was t e r m i n a t e d a f t e r a p p r o x i m a t e l y 925 h r o f o p e r a t i o n w i t h f u e l N o , 30 a t 1 0 p s i a n d 1 7 5 0 rpm.

E x c e s s i v e 1e a k a g e o c c u r r e d b e c a u s e t h e s e a l reached too high temperatures when a n a t t e m p t was made t o r e s t a r t o p e r a t i o n a f t e r b i n d i n g had o c c u r r e d , The o p e r a t i o n o f t h e s e a l c o r r e s p o n d e d t o operation of seals i n other t e s t s i n t h a t t h e l e a k a g e o f t h e s e a l was a p p a r e n t l y t e m p e r a t u r e s e n s i t i v e . When t h e s e a l was t o o h o t or t o o c o l d , l e a k a g e and power s u r g e s r e s u l t e d , b u t u n d e r c e r t a i n c o n d i t i o n s o p e r a t i o n was s m o o t h a n d t h e r e was n o d e t e c t a b l e l e a k a g e . T h e r e have been no i n t e n t i o n a l s t a r t - s t o p tests, although the u n i t h a s been a c c i d e n t a l l y s t o p p e d on s e v e r a l o c c a s i o n s , a n d power s u r g e s have overloaded the motor r e l a y s s e v e r a l times, The u n i t h a s been r e s t a r t e d w i t h l i t t l e d i f f i c u l t y on e a c h o c c a s i o n by h e a t i n g t h e p a c k i n g a r e a and u s i n g a wrench t o “ b r e a k ” t h e s h a f t loose.

Combination Packed and Frozen S e a l w i t h Graphite. The c o n t i n u o u s o p e r a t i o n o f t h e g r a p h i t e - p a c k e d s e a l , mentioned i n t h e p r e v i o u s r e p o r t , was t e r m i n a t e d a f t e r 725 hours.

The s e a l h a d shown n o s i g n s of f a i l u r e , and a f t e r a n o t h e r 150 h r o f p e r i o d i c and s t o p - s t a r t o p e r a t i o n , t h e t e s t was a g a i n t e r m i nated.

During t h e l a t t e r period of o p e r a t i o n , a t t e m p t s were made t o c o n t r o l t h e s e a l temperatures and, t h e r e b y , t h e zone i n which f r e e z i n g was o c c u r r i n g , s i n c e i t w a s b e l i e v e d t h a t m o s t s a t i s f a c t o r y o p e r a t i o n would occur i f f r e e z i n g took place within the graphite region.

Two f a i r l y s t a b l e t e q p e r a t u r e r a n g e s of o p e r a t i o n were f o u n d ; o n e s e t o f t e m p e r a t u r e s corresponded t o t h a t maintained d u r i n g t h e 725-hr period o f continuous o p e r a t i o n and t h e o t h e r s e t w a s a b o u t 150’F l o w e r . O p e r a t i o n w a s u n s t a b l e a t intermediate temperatures.

At the l o w e r t e m p e r a t u r e s , o p e r a t i o n was smooth; t h e r e was no d e t e c t a b l e l e a k a g e ; and t h e u n i t c o u l d be s t o p p e d

26

f o r a s l o n g a s 20 min and s t a r t e d a g a i n by m o t o r p o w e r o n l y .

The s e a l u s e d i n t h i s t e s t was s i m i l a r t o t h e s e a l s used i n other tests i n t h a t l e a k a g e o c c u r r e d when t h e s e a l w a s t o o h o t or t o o c o l d .

Graphite Packed S e a l . I n an a t t e m p t t o determine t h e b e n e f i t s of h o l d i n g t h e t r a n s i t i o n from f l u i d t o s o l i d w i t h i n t h e g r a p h i t e , a t e s t was s e t up t h a t i n c l u d e d a l o n g (4 i n . 1, g r a p h i t e p a c k e d , s t u f f i n g box.

In order to o b t a i n mor e c o m p l e t e t e m p e r a t u r e d a t a , f o u r t h e r m o c o u p l e s were i n s t a l l e d i n t h e r o t a t i n g s h a f t , a n d s i g n a l s were taken o f f through s l i p rings.

After a d r y r u n , f l u o r i d e s were i n t r o d u c e d and t h e s e a l immediately s t a r t e d l e a k i n g graphite.

The G r a p h i t a r r i n g s u s e d a s retainers did not contain the graphite a t the top of the seal.

A p p r o x i m a t e l y 3/4 i n . o f I n c o n e l b r a i d w a s t h e n a d d e d , a n d t h e g r a p h i t e was successfully retained.

The m o t o r f o r t h i s t e s t was a 5 - h p u n i t .

Operation s t a r t e d off f a i r l y normally, but the temperatures adjacent to the seal began t o i n c r e a s e .

Cooling of the b e a r i n g h o u s i n g and t h e g l a n d was s t a r t e d , but the temperatures continued t o rise.

The t e m p e r a t u r e s n e v e r became s t a b l e ; t h e y f l u c t u a t e d o v e r a r a n g e o f 940 t o 2190’F t h r o u g h o u t t h e seal region.

T h e h o t t e s t p o i n t was apparently near the middle of the p a c k i n g , and t h e l o w e s t t e m p e r a t u r e s were i n t h e r e g i o n s o f t h e b e a r i n g s and t h e f l u o r i d e . The m o l t e n f l u o r i d e was a c t i n g a s a c o o l a n t i n t h i s t e s t .

The t e m p e r a t u r e s c o n t i n u e d t o i n c r e a s e u n t i l t h e t e s t h a d t o be t e r m i n a t e d a f t e r a p p r o x i m a t e l y 50 h r o f o p e r a t i o n because the s h a f t ,froze.

The s h a f t c o u l d be r e s t a r t e d by m o t o r power a f t e r i t c o o l e d , b u t would n o t c o n t i n u e t o o p e r a t e when h i g h e r t e m p e r a t u r e s were r e a c h e d .

A t n o time was t h e r e any d e t e c t a b l e leakage; however, severe s h a f t scoring occurred.

A p i c t u r e o f t h e s e a l and s h a f t c u t t h r o u g h t h e c e n t e r l i n e i s shown i n Fig. 2.3.

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27

ANP PROJECT QUARTERLY PROGRESS REPORT 1 3/16-in.-dia s h a f t i s q u i t e e v i d e n t ; other p o r t i o n s of t h e s h a f t ( a l s o a t v e r y h i g h t e m p e r a t u r e s ) showed no markings whatsoever.

The c o n d i t i o n of t h e g r a p h i t e i t s e l f i s of i n t e r e s t , s i n c e i t a p p a r e n t l y p a c k e d i n more or l e s s (1 c o n c e n t r i c ’ ’ r a d i a l l a y e r s t h a t varied in thickness along the length of the seal.

The l a y e r s a d h e r e d a t times t o t h e s h a f t and r o t a t e d , and a t o t h e r times they adhered t o each o t h e r and remained s t a t i o n a r y .

The powder was e x c e p t i o n a l l y f i n e and v e r y “ g r e a s y ” ; t h e “ c o n c e n t r i c ” l a y e r s were v e r y s l i m y ; a n d t h e r e was n o v i s i b l e evidence of f l u o r i d e p e n e t r a t i o n .

Rotating-Shaft Seal Test.

The a p p a r a t u s f o r t h e t e s t s of t h e r o t a t i n g shaft seal consists of a container f o r t h e packing m a t e r i a l being t e s t e d , an u p p e r c o m p r e s s i o n g l a n d t h a t e x e r t s p r e s s u r e on t h e p a c k i n g , a l a n t e r n g l a n d l o c a t e d midway i n t h e c o n t a i n e r , and a s h a f t e x t e n d i n g t h r o u g h t h e assembly.

The s h a f t r o t a t e s i n a b e a r i n g b e n e a t h t h e assembly and i s d r i v e n by a m o t o r m o u n t e d a b o v e .

The p a c k i n g c o n t a i n e r i s m o u n t e d on f o u r r o l l e r s and i s r e s t r a i n e d from t u r n i n g w i t h t h e s h a f t by two t e n s i o n s p r i n g s .

The t o r q u e n e c e s s a r y t o t u r n t h e s h a f t i s i n d i c a t e d by a p o i n t e r a n d a c a l i b r a t e d s c a l e on t h e a s s e m b l y .

Fluorides are forced under pressure from a f i l l t u b e i n t o t h e c o n t a i n e r through t h e l a n t e r n gland.

During the tests, t h e temperature of t h e m i d p o i n t o f t h e p a c k i n g c o n t a i n e r was 1500’F; t h e t e m p e r a t u r e o f t h e l o w e r s h a f t o p e n i n g was 1400’F; t h e p r e s s u r e w a s 20 p s i .

The p a c k i n g m a t e r i a l s t e s t e d were MoS, a n d p o w d e r e d g r a p h i t e .

T h e MoS, p a c k i n g b e g a n t o l e a k a f t e r 1 h r o f o p e r a t i o n . The t o r q u e r e q u i r e d t o t u r n t h e s h a f t a t 350 rpm was 2 ft-lb.

The g r a p h i t e t e s t r a n f o r 8 h r b e f o r e l e a k a g e o c c u r r e d , and t h e same t o r q u e was r e q u i r e d f o r r o t a t i o n .

T h e r e was c o n s i d e r a b l e wear on t h e upper packing gland.

The s h a f t had t o b e s t a r t e d and s t o p p e d a number o f times because o f s e v e r e v i b r a t i o n .

28

Packing P e n e t r a t i o n T e s t s .

The apparatus used i n the packing penet r a t i o n t e s t s and t h e r e s u l t s o f s e v e r a l t e s t s were d e s c r i b e d p r e v i o u ~ l y . ( ~ F) u r t h e r t e s t s h a v e b e e n made and t h e r e s u l t s a r e p r e s e n t e d i n t h e following.

S t a i n l e s s steel b r a i d impregnated w i t h MoS, w a s c o m p r e s s e d a n d h e a t e d twice t o t h e annealing temperature, with f u r t h e r compression a f t e r each heating.

This packing held the fluorides f o r 1/2 h r a t 2 p s i , but when t h e p r e s s u r e w a s i n c r e a s e d t o 5 p s i , leakage occurred.

Examination showed t h a t t h e l e a k a g e p a t h was a l o n g the walls of the containers, the screw stem, and t h e s t r a n d s o f t h e braid.

I t c o u l d n o t be d e t e c t e d t h a t a n y f l u o r i d e m i x e d w i t h t h e MoS, o r p e n e t r a t e d through it.

A s e c o n d b o r o n n i t r i d e t e s t was r u n i n an a s s e m b l y w i t h much s m a l l e r clearances than those used f o r t h e p r e v i o u s boron n i t r i d e test.

In this t e s t , i t was p o s s i b l e t o r a i s e t h e p r e s s u r e t o 30 p s i , and o p e r a t i o n was c o n t i n u e d f o r 234 h r b e f o r e l e a k a g e occurred.

A t e s t w i t h J . T. B a k e r C h e m i c a l Co. p o w d e r e d g r a p h i t e p r e v i o u s l y r e p o r t e d ( 4 ) h a s c o n t i n u e d f o r 240 h r with no leakage.

A n a l y s i s showed t h a t t h e p a c k i n g was a p p r o x i m a t e l y 50% a m o r p h o u s c a r b o n .

Three more g r a p h i t e s h a v e b e e n t e s t e d , and i n a l l c a s e s i t was p o s s i b l e t o r a i s e t h e p r e s s u r e t o 30 p s i w i t h o u t l e a k a g e occurring.

T h e a n a l y s e s and r e s u l t s a r e given i n Table 2.3.

There should b e a minimum o f a m o r p h o u s c a r b o n i n t h e g r a p h i t e b e c a u s e i t would b e expected t o increase the f r i c t i o n between a r o t a t i n g s h a f t and t h e p a c k i n g ; however, t h e g r a p h i t e w i t h t h e h i g h e s t amorphous c a r b o n c o n t e n t sealed f o r the longest periods.

That t h e packing i n t h e f i r s t test did n o t l e a k whereas t h e packing i n t h e l a t e r (4)ANP

Quar.

1439, p . 2 3 .

Prog. R e p . Dec.

10.

1952.

ORNL-

PERIOD ENDING MARCH 1 0 , 1 9 5 3

(%I

HOURS OF O P E R A T I O N B E F O R E LEAKAGE OCCURRED

10

22

Dixon M i c r o f y n e g r a p h i t e

50

75

Amer. G r a p h i t e Co. No. 620 powdered g r a p h i t e

50

63

PACKING MATERIAL

Dixon No.

A N A L Y S I S O F AMORPHOUS CARBON CONTENT

2 flake graphite

tests did, although the physical c h a r a c t e r i s t i c s o f t h e g r a p h i t e s were t h e same, m i g h t b e t h e r e s u l t o f f u e l No. 1 4 b e i n g u s e d i n t h e f i r s t t e s t a n d f u e l No. 3 0 i n t h e l a t e r test.

Frozen-Sodium and Frozen-Lead Seal for NaK. I t was r e p o r t e d p r e v i o u s l y ( ' ) t h a t t e s t s w e r e u n d e r way t o d e t e r m i n e t h e f e a s i b i l i t y o f s e a l i n g a NaK pump w i t h an e x t e r n a l l y s u p p l i e d f r o z e n sodium or f r o z e n - l e a d s e a l .

Although t h e p r e l i m i n a r y t e s t s were e n c o u r a g i n g , subsequent tests revealed t h a t s e a l l i f e ( t h e t i m e before f a i l u r e because o f a l l o y i n g ) was, i n g e n e r a l , i n v e r s e l y p r o p o r t i o n a l t o NaK t e m p e r a t u r e a n d t h a t t h e s e a l s were u n r e l i a b l e f o r p e r i o d s of o p e r a t i o n g r e a t e r than 100 h o u r s .

In t h e f r o z e n sodium s e a l , t h e s o d i u m a l l o y s w i t h t h e NaK a n d f o r m s a low-melting-point a l l o y i n the s e a l t h a t c a n n o t be f r o z e n w i t h roomtemperature cooling water; a s a r e s u l t t h e s e a l is completely l o s t .

Ref r i g e r a t i o n , with t e m p e r a t u r e s below t h e m e l t i n g p o i n t o f e u t e c t i c NaK (12'F), would be r e q u i r e d t o a s s u r e seal retention.

In t h e frozen-lead s e a l , the lead a l l o y s w i t h t h e NaK and f o r m s a h i g h melting-point alloy; a s a r e s u l t t h e r e i s s h a f t s e i z u r e and i t i s i m p o s s i b l e t o o p e r a t e w i t h r e a s o n a b l e power requirements. ("AMP

Quar. P r o g . R e p .

1439. p . 2 6 .

D e c . 1 0 , 1 9 5 2 , ORNL-

A R E V a l v e Test.

Preliminary gas and l i q u i d leakage t e s t s have been r u n o n t h e ARE p n e u m a t i c a l l y d r i v e n v a l v e s u p p l i e d by F u l t o n - S y l p h o n Co. The v a l v e is c o n s t r u c t e d of Inconel and h a s a S t e l l i t e - t o - S t e l l i t e v a l v e and s e a t .

T h e s h a f t - s e a l i n g member i s a four-ply Inconel bellows.

The valve is adaptable t o being either n o r m a l l y c l o s e d or n o r m a l l y o p e n e d , a n d t h e p o s i t i o n i s r e v e r s e d by a p p l i c a t i o n o f 15 p s i o f a i r p r e s s u r e t o a l a r g e bellows actuator.

For t h e i n i t i a l t e s t , t h e valve was mounted v e r t i c a l l y and a d a p t e d f o r normally closed operation.

With t h e v a l v e a t room t e m p e r a t u r e , g a s l e a k a g e was s m a l l w i t h t e s t p r e s s u r e s f r o m 30 t o 6 0 p s i t h a t w e r e f i r s t a p p l i e d up a g a i n s t t h e v a l v e s e a t a n d t h e n down o n i t .

Raising the v a l v e t e m p e r a t u r e t o 1050'F c a u s e d a slight increase in gas leakage; however, t h e l e a k a g e r e m a i n e d s m a l l .

Testing for liquid leaks with the ARE f u e l , N a F - Z r F , - U F , (50-46-4 mole %), a t 1100'F r e v e a l e d t h a t t h e r e was n o l e a k a g e w i t h t e s t p r e s s u r e s o f 30 t o 60 p s i a p p l i e d b o t h a b o v e and below t h e s e a t . T h i s t e s t w a s r e p e a t e d s e v e r a 1 time s I n a t e s t a t 1300째F, s l i g h t l e a k a g e (0.3 in.3/hr or l e s s ) occurred a t various intervals.

H o w e v e r , i t was concluded t h a t the leakage a t t h i s t e m p e r a t u r e was n o t s e r i o u s .

The i n i t i a l c h e c k s a t 1 5 0 0 ' F were v e r y S u b s e qu e n t c h e c k s , s u c c e s s f u 1.

.

29

ANP PROJECT QUARTERLY PROGRESS REPORT however, showed a v e r y s e r i o u s l e a k a g e r a t e , 1 2 0 i n . 3 / h r , t h a t c o u l d n o t be c o r r e c t e d by r e s e a t i n g t h e v a l v e .

I t was c o n c l u d e d t h e r e f o r e t h a t t h e v a l v e m i g h t be u s a b l e f o r s e v e r a l c y c l e s a t 1500°F b u t t h a t i t c o u l d n o t be expected t o hold t i g h t i f cycled i n d e f i n i t e l y .

D i f f i c u l t y a t t h e e l e v a t e d temperat u r e was e x p e r i e n c e d i n t h a t t h e v a l v e s t u c k when l e f t c l o s e d f o r s h o r t periods.

However, i n a l l c a s e s t o d a t e , t h e v a l v e h a s e v e n t u a l l y become o p e r a b l e by i n c r e a s i n g t h e p r e s s u r e u p t o 30 p s i o n t h e v a l v e a c t u a t o r .

I n o n e i n s t a n c e a t 1100°F and a n o t h e r a t 1500°F, i t was n e c e s s a r y t o v i b r a t e t h e v a l v e body t o g e t t h e v a l v e open.

When t h e v a l v e was c u t f o r i n s p e c t i o n , i t was f o u n d t h a t some b i n d i n g o f t h e S t e l l i t e f a c e s had occurred.

HEAT EXCHANGER SYSTEMS

G. D. Whitman D. F. Salmon ANP D i v i s i o n

'

Sodium-to-Air Radiator Tests.

The s o d i u m - t o - a i r r a d i a t o r t e s t e d had a c o r e element with 30 f i n s p e r inch.(6) T h i s t e s t r a n f o r 200 h r a n d was t h e n t e r m i n a t e d b e c a u s e o f poor h e a t t r a n s f e r performance.

The maximum, o v e r - a l l , h e a t t r a n s f e r c o e f f i c i e n t s o b t a i n e d were o f t h e o r d e r of 6 B t u / h r * f t 2 * " F , which i s f a r below t h e p r e d i c t e d p e r f o r m a n c e .

I t was d i s c o v e r e d , a f t e r i n l e t sodium t e m p e r a t u r e s o f 1500°F were r e a c h e d , t h a t v e r y few of t h e N i c r o b r a z e d f i n - t o - t u b e j o i n t s were good.

The r a d i a t o r could be seen through t h e a i r e x h a u s t , and i t was o b s e r v e d t h a t w i t h minimum a i r f l o w l e s s t h a n 1 0 % of t h e n i c k e l f i n s showed any h e a t color.

The s m a l l amounts o f b r a z e material used t o avoid c l o s i n g t h e 0 . 0 2 5 - i n . f i n - t o - f i n g a p s were apparently i n s u f f i c i e n t t o completely j o i n t h e f i n s and t u b e s .

No o x i d e plugging occurred i n the radiator (6)ANP

Quar. P r o g . R e p . D e c .

1439, p . 2 7 .

30

10. 1 9 5 2 , ORNL-

tubes during t h i s relatively short r u n , and t h e b y p a s s f i l t e r c i r c u i t was o p e r a t e d w i t h o u t d i f f i c u l t y .

A R o o t s C o n n e r s v i l l e g a s pump d r i v e n by a 2 - h p V a r i d r i v e h a s b e e n installed i n place of the Buffalo c e n t r i f u g a l blower s o t h a t a wider r a n g e o f a i r f l o w s and b e t t e r f l o w r e g u l a t i o n c a n be o b t a i n e d .

B i f l u i d Heat T r a n s f e r L o o p .

The b i f l u i d h e a t t r a n s f e r l o o p , ( ' ) which h a s been i n o p e r a t i o n f o r a p p r o x i m a t e l y two m o n t h s , t r a n s f e r s h e a t f r o m f u e l No. 3 0 t o NaK. The h e a t t r a n s f e r takes place in a concentric tube section; the center tube contains t h e h o t f l u o r i d e a n d t h e NaK i s i n t h e annulus.

The c e n t e r t u b e h a s an i n s i d e d i a m e t e r o f 0 . 2 6 9 i n . a n d an L / D r a t i o o f 40, whereas t h e a n n u l u s h a s an L/D r a t i o o f 22.

H e a t t r a n s f e r d a t a on t h e f l u o r i d e f u e l h a v e been t a k e n o v e r a R e y n o l d ' s number r a n g e o f from 5 , 0 0 0 t o 2 0 , 0 0 0 , which c o r r e s p o n d s t o v e l o c i t i e s o f from 8 t o 30 f p s . The maximum f l u o r i d e t e m p e r a t u r e was 1400"F, and t h e temperature drop across the heat e x c h a n g e r was v a r i e d f r o m 1 5 t o 40°F. The NaK-side d a t a were t a k e n a t R e y n o l d ' s numbers from 20,000 t o 100,000.

The o v e r - a l l h e a t t r a n s f e r c o e f f i c i e n t f o r h e a t f l u x e s from 3 0 0 , 0 0 0 t o 5 0 0 , 0 0 0 B t u / h r . f t 2 h a s v a r i e d from 1 0 0 0 t o 2 5 0 0 B t u / h r * f t 2 *O F .

Satisfactory separation of the individual c o e f f i c i e n t s h a s n o t been accomplished because o f t h e n e c e s s i t y o f e v a l u a t i n g thermal e n t r a n c e e f f e c t s and because o f what a p p e a r s t o b e f o u l i n g i n t h e exchanger.

It i s possible that fouling occurred, because t h e r e w a s f l o w r e s t r i c t i o n when t h e t e m p e r a t u r e o f t h e NaK e n t e r i n g t h e h e a t e x c h a n g e r was l o w e r e d t o t h e f l u o r i d e m e 1 t i n g p o i n t ( a p p r o x i m a t e l y 950'F).

T h e pump f o r c i r c u l a t i n g f l u o r i d e f u e l h a s operated s a t i s f a c t o r i l y with a minimum o f g a s l e a k a g e .

T h i s pump ( 7 ) A N P Q u a r . P r o g . R e p . D e c . 1 0 , 1 9 5 2 , ORNL-

1439, p . 2 8 .

t

PERIOD ENDING MARCH 1 0 , 1 9 5 3 i s a sump pump i n w h i c h t h e l i q u i d leve is controlled with a sparkplug-probe.

The s e a l o f t h e pump i s o f t h e water-cooled, rotary-face type t h a t c o n s i s t s of silver-impregnated graphite running against tool steel.

A R E FUEL CIRCUIT MOCKUP G. D. Whitman, ANP D i v i s i o n

A mockup o f t h e ARE f u e l c i r c u i t h a s been c o n s t r u c t e d f o r i n v e s t i g a t i n g t h e hydrodynamic s t a b i l i t y of t h e d e s i g n and t h e c h a r a c t e r i s t i c s o f t h e l i q u i d flow i n t h e s u r g e tanks.

The s y s t e m , shown s c h e m a t i c a l l y i n F i g . 2 . 4 , was c o n s t r u c t e d from b l a c k i r o n p i p e , and i t h a s v i e w i n g windows i n t h e s u r g e t a n k s and g l a s s s e c t i o n s i n t h e l i n e s leaving the surge tanks.

The surge tanks a r e of the s i z e t o be u s e d i n t h e ARE, and t h e two i d e n t i c a l pumps h a v e c h a r a c t e r i s t i c s i n t h e f l o w r a n g e t o b e i n v e s t i g a t e d ( 0 t o 50 gpm)

t h a t are quite similar t o those of the p r o p o s e d ARE pumps.

Speed v a r i a t i o n o f t h e pumps i s o b t a i n e d by u s i n g 5-hp V a r i d r i v e u n i t s .

The h e a t exchangers a r e simulated by g a t e v a l v e s , and t h e r e a c t o r c a n be s i m u l a t e d by a G l o b e v a l v e or by t h e g l a s s model t h a t was p r e v i ou s l y d e s c r i bed.

Thus f a r , water and a w a t e r g l y c e r i n e solution h a v e b e e n u s e d i n t h e system.

The r e s u l t s a r e t h e r e f o r e b a s e d on o b s e r v a t i o n s made w i t h w a t e r o f approximately one-third t h e density and o n e - t e n t h t h e v i s c o s i t y o f t h e f u e l and with the glycerine-water solution of approximately one-third t h e d e n s i t y o f t h e f u e l a n d t h e same viscosity.

T e s t s h a v e begun w i t h 1 - l , 2 - 2 , bromoethane, f o r which t h e room- t e m p e r a t u r e d e n s i t y and v i s c o s i t y a r e n e a r l y t h e same a s t h o s e o f f u e l No. 30 a t 1400'F. T h e ARE s y s t e m c o m p r i s e s t w o , s i m i l a r , l i q u i d h e a t exchanger and

ANTIVORTEXING AND PROBE ASSEMBLY

L

I

ROTAMETER

GLASS PIPE-

'

H E A T EXCHANGER

PRESSURE GAGE

L

\

-

Y

1

H E A T EXCHANGER REACTOR

2-in. IPS

// /

Fig. 2.4.

/

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FLUID FLOW

-

Sketch of ARE Fuel-Circuit Mockup.

31

ANP PROJECT QUARTERLY PROGRESS REPORT

'

s u r g e t a n k c i r c u i t s - one f o r m o d e r a t o r c o o l a n t and t h e o t h e r f o r f u e l .

Each c i r c u i t i n c l u d e s two p a r a l l e l c i r c u i t s , e a c h o f which i n c l u d e s , i n s e r i e s , a p a i r o f h e a t exchangers ( i n p a r a l l e l ) , a pump, and a s u r g e t a n k . A s d e s i g n e d , e a c h s u r g e t a n k was t o r e c e i v e a n d d e l i v e r the e n t i r e flow of i t s part i c u l a r pump, However, t h e s u r g e t a n k s of t h e m o d e r a t o r c o o l a n t c i r c u i t s h a v e now b e e n p r o v i d e d w i t h b y p a s s e s t o r e d u c e t h e f l o w t h r o u g h them t o l o w l e v e l s and t h e r e b y r e d u c e g a s entraining turbulence t o acceptable values.

The m o d e r a t o r c o o l a n t f l o w r a t e i s , i n general, s e v e r a l times higher than the f u e l flow rate.

However, i n t h e f u e l c i r c u i t t h e r e are strong incentives to retain complete flow c o n t r o l of a l l f u e l , inasmuch a s t h e system w i l l be f i l l e d i n i t i a l l y with nonuranium-bearing s a l t s and w i l l h a v e U 2 3 5 - b e a r i n g s a l t s added t o i t u n t i l c r i t i c a l i t y i s reached.

Once a d d i t i o n s t a r t s , n o s a l t c a n be r e m o v e d o r d r a i n e d , a n d completeand uniform mixing must occur.

C o n s e q u e n t l y , t h e e x p a n s i o n or s u r g e t a n k s must p r o v i d e s u f f i c i e n t c a p a c i t y t o receive the enriched f u e l ( about 15% o f t h e s y s t e m v o l u m e ) and a l s o t o provide f o r fuel thermal expansion from 1 0 0 0 t o 1500'F ( a b o u t 10% o f s y s t e m v o l u m e ) . The t h e r m a l e x p a n s i o n w i l l b e a b o u t 200'F m o r e t h a n t h a t anticipated.

There i s a l s o a s t r o n g i n c e n t i v e f o r minimum volume h o l d u p o f enriched f u e l i n each surge tank.

V o r t e x e s and B u b b l e s .

The system was o p e r a t e d i n i t i a l l y w i t h w a t e r , a n d t h e s u r g e t a n k s were i n v e s t i g a t e d f o r v o r t e x i n g 'above t h e d i s c h a r g e l i n e s . The s u r g e t a n k s h a d n o b a f f l e s , a n d e n t r a i n e d g a s was o b s e r v e d i n t h e d i s c h a r g e s a t a l l flow r a t e s above 10 gpm w i t h t h e t a n k s h a l f f u l l o f l i q u i d .

T h i s g a s e n t r a i n m e n t was due t o v o r t e x i n g of the liquid leaving the tanks.

A t lower l i q u i d l e v e l s , vortexing occurred a t flow r a t e s of l e s s t h a n 1 0 gpm.

Many g e o m e t r i e s w e r e t r i e d f o r b r e a k i n g up t h i s v o r t e x i n g , and a

32

b a f f l e d e s i g n was f i n a l l y d e v e l o p e d t h a t a l l o w e d w a t e r f l o w r a t e s o f up t o 4 0 gpm t o b e p u t t h r o u g h t h e t a n k s without v i s i b l e gas entrainment i f a minimum l e v e l o f a p p r o x i m a t e l y 4 i n . was m a i n t a i n e d i n t h e 1 0 - i n . - d i a t a n k s .

This antivortexing baffle consists o f a f l a t p l a t e , 6 by 8 i n . , a t t a c h e d t o t h e bottom o f t h e probe w e l l t h a t i s centered over the discharge l i n e .

The p r o b e w e l l was c u t o f f s o t h a t t h e p l a t e c o u l d b e l o c a t e d 2 i n . from t h e bottom o f t h e t a n k .

There a r e t h r e e vertical fins attached to the p l a t e , o n e i n t h e c e n t e r and one n e a r e a c h edge, so t h a t they a r e approximately 1/8 i n . from t h e b o t t o m o f t h e c y l i n d r i c a l tank. This device serves t o g u i d e t h e flow from t h e i n l e t t o t h e o u t l e t with less v e l o c i t y l o s s than i n t h e open t a n k , and t h e flow i s res t r a i n e d from g o i n g i n o n t h e s i d e s and e d g e n e a r t h e end o f t h e t a n k w h e r e t h e more s e v e r e v o r t e x i n g always occurred When t h e g l y c e r i n e s o l u t i o n w a s t r i e d , t h e r e a p p e a r e d t o be l e s s tendency t o e n t r a i n gas i n t h e s u r g e tanks, A t r a t e d f l o w , 4 0 gpm, l o w e r f l u i d l e v e l s c o u l d be m a i n t a i n e d i n the surge tanks without there being v i s i b l e gas e n t r a i n m e n t i n t h e d i s charge.

I t had been f e l t t h a t F r o u d e ' s modulus s h o u l d be a p p l i c a b l e , s i n c e t h e f l u i d m o c k u p a n d t h e ARE f u e l c i r c u i t s were s i m i l a r , and t h a t g r a v i t y f o r c e s s h o u l d predominate on the f r e e surfaces i n the tanks.

Since t h e mockup s u r g e t a n k s a r e f u l l ARE s i z e , t h e ARE f u e l f l o w r a t e s w e r e maintained w i t h the water and t h e glycerine-water s o l u t i o n for t h i s investigation i n order t o maintain hydraulic similarity.

The m o d e r a t o r c i r c u i t i n t h e ARE i s quite similar i n design to the fuel circuit.

T h e Na o r N a K f l o w ( a b o u t 100 gpm) c a n n o t be p u t t h r o u g h a s u r g e t a n k o f ARE d i m e n s i o n s w i t h o u t t h e r e being very s e v e r e gas entrainment i n t h e d i s c h a r g e . T h i s c o n d i t i o n c a n be r e m e d i e d by b y p a s s i n g m o s t o f t h e f l o w

.

PERIOD ENDING MARCH 1 0 , 1 9 5 3 a r o u n d t h e t a n k s or by u s i n g t h e t a n k s a s s t a n d pipes only.

The f i r s t remedy would be t h e more d e s i r a b l e , s i n c e g a s r e m o v a l would be more e f f e c t i v e .

I t was f o u n d t h a t t h e s u r g e t a n k s removed v i s i b l e g a s b u b b l e s i n t h e w a t e r and g l y c e r i n e - w a t e r s o l u t i o n .

A i r b u b b l e s o f t h e o r d e r o f 1/8 i n . i n d i a m e t e r and l a r g e r were removed i n a v e r y few c y c l e s , and t h o s e s o s m a l l a s t o b e b a r e l y v i s i b l e were removed a f t e r a n h o u r or s o o f c i r c u l a t i o n a t low or r a t e d f l o w s , When t h e g l y c e r i n e - w a t e r s o l u t i o n was f i r s t t r a n s f e r r e d t o t h e l o o p , i t was n e a r l y o p a q u e b e c a u s e o f t h e f i n e l y divided gas bubbles, but t h e s o l u t i o n was c l e a r a f t e r c i r c u l a t i o n through the surge tanks for approximately 1 hour.

The s y s t e m t e s t e d f o r gas removal had a c a p a c i t y o f 15 g a l l o n s .

O p e r a t i o n a 1 Ins t a b i 1 it i e s .

The s y s t e m h a s a l s o been i n v e s t i g a t e d w i t h r e s p e c t t o p u m p f a i l u r e s and o p e r a t i o n a l i n s t a b i l i t i e s . During operation with e a c h pump d e l i v e r i n g 30 t o 4 0 gpm a t a p p r o x i m a t e l y 45 p s i h e a d , i f o n e pump i s s h u t down t h e r e m a i n i n g pump i m m e d i a t e l y becomes g a s bound, s t a r t s pumping i n t e r m i t t e n t l y , and s e v e r e l y g a s s e s the loop.

The g a s s i n g o f t h e pump t h a t r e m a i n s o p e r a b l e r e s u l t s from t h e t r a n s f e r o f l i q u i d from t h e surge tank i n the operating loop t o t h e s u r g e t a n k i n t h e l o o p t h a t was s h u t down; t h a t i s , when o n e pump i s shut off, its associated surge tank, w h i c h i s e s s e n t i a l l y a t pump s u c t i o n pressure, is subjected to the disc h a r g e p r e s s u r e o f t h e o p e r a t i n g pump a n d t h e r e f o r e g a s volume i s c o m p r e s s e d and c a u s e s t r a n s f e r o f l i q u i d from t h e i n -a l o o r , t o t h e ~ O O Dt h a t w a s s h u t down. t i n g a t or n e a r ops, e i t h e r the loop i m m e d i a t e l y i s o l a t e d from t h e r t h e r e m a i n i n g pump s t o p p e d . e loop containing the inoperable pump m u s t be v a l v e d o u t o f t h e s y s t e m b e f o r e flow i s r e s t a r t e d .

Also, a t r e l a t i v e l y h i g h f l o w or p r e s s u r e r i s e *

-

a c r o s s t h e pumps, i m p e l l e r s p e e d s must be t h e same f o r b o t h pumps , o r e x c e s s i v e a m o u n t s o f l i q u i d w i l l be t r a n s f e r r e d from o n e s u r g e t a n k t o t h e o t h e r .

In an a t t e m p t t o m a i n t a i n e q u i l i b r i u m b e t w e e n t h e two t a n k s i n c a s e o f a pump f a i l u r e , t h e y were c o n n e c t e d by a liquid line.

I t was n e v e r p o s s i b l e t o operate satisfactorily with t h i s line o p e n b e c a u s e o n e pump would d e v e l o p a s l i g h t l y g r e a t e r h e a d a n d takle o v e r t h e e n t i r e l o a d and t h u s i n d u c e back f l o w t h r o u g h t h e o t h e r pump.

A t such t i m e s , t h e r e was h e a v y f l o w f r o m o n e tank t o the o t h e r through the liquid l i n e c o n n e c t i n g t h e two s u r g e t a n k s , Flow t h r o u g h t h e h e a t e x c h a n g e r c i r c u i t s would n o t d r o p o f f a p p r e c i a b l y .

T h e pump c a r r y i n g t h e l o a d c o u l d e a s i l y s u p p l y both h e a t exchangers and a s m a l l back f l o w t h r o u g h t h e o t h e r pump.

The h e a d f l o w c h a r a c t e r i s t i c s o f t h e pumps a r e shown i n F i g . 2 . 5 .

It w i l l be n o t e d t h a t b e t w e e n s h u t - o f f a n d 5 0 gpm t h e r e i s l i t t l e o r no d r o p i n h e a d , a n d a t s o m e s p e e d s is v e r y s l i g h t p u l s a t i o n p o i n t c a n be d e t e c t e d .

These f l a t curves e x p l a i n t h e a b i l i t y o f o n e pump t o h a n d l e t h e t o t a l f l o w o f t h e r e a c t o r and h e a t exchanger, a s previously mentioned.

One pump r u n n i n g a t a s l i g h t l y h i g h e r speed can e a s i l y buck t h e o t h e r pumps and h a n d l e t h e t o t a l l o o p l o a d w i t h o u t I!osing s u f f i c i e n t head t o f a l l below t h e s h u t - o f f h e a d o f t h e o t h e r pump.

D u r i n g o p e r a t i o n b e l o w 2 5 gpm p e r pump, o s c i l l a t i o n s h a v e b e e n o b s e r v e d i n t h e flow.

T h e s e h a v e neve:r b e e n s e r i o u s and c o u l d a l w a y s be r e d u c e d t o n e g l i g i b l e a m p l i t u d e by i n c r e a s i n g t h e flow r a t e o f t h e system.

The loscill a t i o n s a r e e v i d e n c e d by a n i n c r e a s e i n flow r a t e and l i q u i d l o s s i n one pump c i r c u i t a n d a s i m u l t a n e o u s d e c r e a s e i n flow r a t e and l i q u i d g a i n i n the other circuit.

The conldition t h e n r e v e r s e s and t h e p e r i o d o f t h e o s c i l l a t i o n i s a p p r o x i m a t e l y 2 seconds.

T h e maximum c h a n g e i n f l o w r a t e h a s b e e n f 2 . 5 gpm a t f l o w r a t e s o f 2 0 gpm p e r pump.

T h i s d i s t u r b a n c e c a n be

33

ANP PROJECT QUARTERLY PROGRESS REPORT

Fig. 2.5.

34

Head F l o w C h a r a c t e r i s t i c s o f Pumps.

PERIOD ENDING MARCH 1 0 , 1 9 5 3 e x p l a i n e d by t h e pump c h a r a c t e r i s t i c s and t h e a b s e n c e o f check v a l v e s i n t h e d i s c h a r g e l i n e s o f t h e p a r a l l e l pump . arrangement.

I n t h i s p a r t i c u l a r s y s t e m , when o n e pump t a k e s t h e e n t i r e l o a d , t h e r e i s a subsequent pressure rise i n the surge t a n k o f t h e s t a l l e d pump.

This i s t h e n s e e n a s an i n c r e a s e i n d i s c h a r g e p r e s s u r e o f t h e s t a l l e d pump, w h i c h t h e n o v e r p o w e r s th.e pump h a n d l i n g t h e load and momentarily r e v e r s e s t h e situation, The a c t u a l r e v e r s a l o f f l o w o c c u r s only i n the l i n e connecting t h e surge t a n k s t h r o u g h t h e pumps, t h a t i s , t h e s u c t i o n l i n e s a n d t h e common d i s charge line.

The flow t h r o u g h t h e h e a t exchangers is unsteady but does n o t r e v e r s e o r s t o p . The f l o w t h r o u g h the reactor appears t o b e q u i t e steady, e v e n t h o u g h i t i s b e i n g s u p p l i e d by a l t e r n a t e pumps.

An E s t e r l i n e Angus r e c o r d i n g w a t t meter w a s i n s t a l l e d on o n e pump m o t o r , a n d i t was e s t a b l i s h e d t h a t d u r i n g t h e s e o s c i l l a t i o n s t h e pump a l t e r n a t e l y c a r r i e d f u l l l o a d and s h u t - o f f head demand.

T h i s c o n d i t i o n c a n be e f f e c t i v e l y c o r r e c t e d by i n s e r t i n g a r e s i s t a n c e i n t h e common pump d i s c h a r g e l i n e s o t h a t s t a b l e pump c h a r a c t e r i s t i c s are obtained. A 2-psi inc r e a s e in p r e s s u r e i s s u f f i c i e n t t o r e s u l t i n a d i s c h a r g e curve which shows t h a t t h e h e a d d e c r e a s e s w i t h f l o w f r o m s h u t - o f f t o maximum f l o w .

T h i s was d e m o n s t r a t e d by p a r t l y c l o s i n g one of the t h r o t t l e valves i n the pump d i s c h a r g e l i n e d u r i n g a n o s c i l l a t i o n ; the disturbance immediately stopped. ow being t e s t e d w i t h romoethane, which has p h y s i c a l r l y t h e same a s t h o s e o f v i s c o s i t y , 9.27 c p s ; f i c g r a v i t y , 2 , 9 5 a t ??OF).

The mockup w i l l a g a i n be u s e d t o c h e c k g a s r e m o v a l and v o r t e x i n g i n t h e s u r g e t a n k s , f i l l i n g and d r a i n i n g t h e r e a c t o r , pump c h a r a c t e r i s t i c s and f l o w i n s t a b i l i t i e s .

INSTRUMENTATION D. R . Ward P. W . T a y l o r A. L. S o u t h e r n P. G . S m i t h

W. B. McDonald

ANP D i v i s i o n

Pressure Measurement. Two t e s t s o f Moore N u l l m a t i c p r e s s u r e t r a n s m i t t e r s , operating with the 0.005-in. w a l l bellows completely submerged i n t h e ARE f u e l , NaF-ZrF4 -UF4 ( 50- 4 6 - 4 mole %I, a t 1 1 0 0 ” F , have l o g g e d enough o p e r a t i n g time t o make i t seem l i k e l y t h a t t h i s method o f p r e s s u r e m e a s u r e m e n t i s t h e most a d v a n t a g e o u s of any t r i e d t o d a t e .

T h e t r a n s m i t t e r s a r e “ u p s i d e down” i n the sense that the cavity containing t h e bellows and t h e l i q u i d under p r e s s u r e i s open a t t h e t o p . A n i c k e l t r a n s m i t t e r h a s been c y c l e d e v e r y 1 / 2 h r b e t w e e n 10 a n d 3 0 p s i f o r 1 9 0 0 h o u r s .

A t y p e 316 s t a i n l e s s s t e e l t r a n s m i t t e r has operated s i m i l a r l y f o r 1500 hours.

A t h i r d t r a n s m i t t e r o f t y p e 316 s t a i n l e s s s t e e l f i l l e d w i t h l e a d and t o p p e d with a layer o f the molten f u e l has 1500 h r of o p e r a t i n g t i m e , t o d a t e , and i s running s l i g h t l y c o o l e r t h a n t h e o t h e r s , The i n i t i a l z e r o s h i f t i n e a c h c a s e was a p p r o x i m a t e l y 1%o f f u l l scale a t the operating temperature, and d r i f t o v e r t h e 1 5 0 0 - h r p e r i o d was a p p r o x i m a t e l y 2%. H o w e v e r , t h e z e r o p o s i t i o n can be a d j u s t e d e a s i l y , i f necessary.

S e v e r a l o t h e r Moore t r a n s m i t t e r s have been i n s t a l l e d i n dynamic l o o p s for circulating fluorides or liquid metals.

These t r a n s m i t t e r s operate “ r i g h t s i d e up, ” and t h e r e i s t r a p p e d helium around t h e bellows t o p r o t e c t them from t h e l i q u i d .

T h i s method o f p r o t e c t i n g the bellows, alt,hough o p e r a b l e i n m o s t c a s e s , d o e s n o t seem a s s a t i s f a c t o r y a s complete submersion.

T h e ARE f u e l i n t h e n i c k e l t r a n s m i t t e r mentioned above has been r a p i d l y f r o z e n and t h e n r a p i d l y r e m e l t e d t h r e e t i m e s , w i t h n o a p p a r e n t damage t o t h e instrument. This is n o t p o s s i b l e with t h e trapped-gas instrument because of f o u l i n g o f t h e bellows.

I t was a l s o

35

ANP PROJECT QUARTERLY PROGRESS REPORT found t h a t when t h e p r e s s u r e t r a n s m i t t e r is f i l l e d with s t a t i c f u e l , the bellows

t e m p e r a t u r e c a n be m a i n t a i n e d a t 1 1 0 0 ° F o r below, O p e r a t i o n o f t h e b e l l o w s a t t h e reduced temperature reduces t h e corrosion rate.

F a i l u r e of t h e bellows i n one of t h e type 316 s t a i n l e s s s t e e l t r a n s m i t t e r s a f t e r 500 h r o f o p e r a t i o n a t 1 2 0 0 ° F w a s a p p a r e n t l y c a u s e d by o x i d a t i o n , H e l i u m i n s t e a d o f a i r i s now u s e d a s t h e c o n t i n u o u s f 1ow- b a l a n c i n g gas i n the pressure t r a n s m i t t e r tests.

ARE Leak Detection Indicator T e s t s .

There is i n t e r e s t i n developing a s e c o n d a r y method f o r d e t e c t i n g l e a k s i n NaK o r f u e l s y s t e m s i n t h e ARE t o supplement the halogen leak d e t e c t o r .

Experimentation revealed t h a t a sol u t i o n o f p h e n o l r e d c a n be made v e r y s e n s i t i v e t o c h a n g e s i n pH by a d j u s t i n g t h e s o l u t i o n t o a r e d d i s h brown.

When h e l i u m i s p a s s e d o v e r a s u r f a c e o f h o t f u e l and then over t h e s u r f a c e of the i n d i c a t o r s o l u t i o n , t h e s o l u t i o n c h a n g e s c o l o r . L i k e w i s e , i t was found t h a t a c o l d lump o f t h e f u e l d r o p p e d i n t o t h e i n d i c a t o r s o l u t i o n changed t h e i n d i c a t o r toward t h e a c i d d i r e c t i o n .

S l i p R i n g s f o r Temperature Measurement. T h r e e t e s t s o f s l i p r i n g s f o r measuring the temperature inside a r o t a t i n g s h a f t were s t a r t e d .

Because s i l v e r - g r a p h i t e b r u s h e s were n o t a v a i l a b l e , carbon b r u s h e s were used.

One t e s t was c o m p l e t e d i n w h i c h c o p p e r r i n g s a n d c a r b o n b r u s h e s were u s e d .

When t h e b r u s h e s were w e l l r u n - i n , an accuracy i n t h e temperature measurem e n t s o f *P°F a t 1 2 0 0 ° F was o b t a i n e d .

The c o m b i n a t i o n o f c a r b o n b r u s h e s a n d carbon rings is s a t i s f a c t o r y i f a w i p i n g b r u s h i s mounted on t h e r i n g .

I f the r i n g is n o t kept c l e a n , the resistance across the contact increases w i t h t i m e , a n d t h e e r r o r may i n c r e a s e t o +40°F o r more.

A second combination of m a t e r i a l s , coin s i l v e r and silver-impregnated g r a p h i t e , was p l a c e d i n o p e r a t i o n b e f o r e b e i n g t e s t e d , and performance h a s been s a t i s f a c t o r y f o r s e v e r a l

-

36

hundred hours.

In a third test that i s being conducted w i t h type 316 s t a i n l e s s s t e e l r i n g s and carbon b r u s h e s , a n e r r o r o f +20"F h a s d e veloped, b u t i t is a c o n s t a n t e r r o r .

T h e c a r b o, n b r u s h e s w i l l be r e p l a c e d with silver-impregnated graphite b r u s h e s , which s h o u l d r e d u c e t h e e r r o r slightly.

Commerical s l i p r i n g a s s e m b l i e s have been o r d e r e d t h a t w i l l w o r k on e i t h e r a 7 / 8 - o r a 2 1 / 4 - i n . shaft.

Rotameter Type of Flowmeter. T e s t i n g h a s c o n t i n u e d on t h e r o t a m e t e r t y p e o f f l o w m e t e r r e p o r t e d p r e v i o u s l y , ( * ) and a p p r o x i m a t e l y 1000 h r o f o p e r a t i o n h a s been logged i n t h e t e m p e r a t u r e range o f 1100 t o 1300°F. This instrument w i l l m e a s u r e f l o w s o f f u e l No. 30 w i t h 10% a c c u r a c y o v e r t h e r a n g e o f 9 t o 60 gpm.

Two i n s t r u m e n t s o f t h i s t y p e have been t e s t e d , and t h e r e s u l t s i n d i c a t e t h a t t h i s i n s t r u m e n t w i l l be r e l i a b l e f o r ARE o p e r a t i o n .

HANDLING OF FLUORIDES AND LIQUID METALS L. A . Mann J . M. C'i s a r F. M. G r i z z e l l ANP D i v i s i o n D i s t i l l a t i o n o f NaK. NaK h a s b e e n chosen a s t h e p r e c l e a n i n g f l u i d f o r t h e ARE b e f o r e i n t r o d u c t i o n o f f l u o r i d e s a l t s . Since only a small f r a c t i o n o f NaK ( l e s s t h a n 0 . 5 w t %; c f . , s e c . 9 ) c a n be t o l e r a t e d i n t h e f u e l w i t h o u t r e d u c t i o n o f UF, t o UF,, s t u d i e s h a v e b e e n made t o d e t e r m i n e how much NaK remains a f t e r t h e system is d r a i n e d a n d how e f f e c t i v e d i s t i l l a t i o n i s i n removing i t . S i n c e t h e vapor p r e s s u r e of p o t a s s i u m a t any t e m p e r a t u r e i s h i g h e r than t h a t o f sodium, upon d i s t i l l a t i o n t h e a l l o y undergoes r a p i d d e p l e t i o n o f p o t a s s i u m , and t h e r e i s a c o r r e s p o n d i n g enrichment o f sodium.

Therefore each d i s t i l l a t i o n is prog r e s s i v e l y more d i f f i c u l t . The b o i l i n g p o i n t o f sodium i s 1621°F a t 1 atm; h e n c e , vacuum d i s t i l l a t i o n i s u s e d t o avoid excessive temperatures, An (*)ANP Q u a r . P r o g . R e p . D e c .

1439, p . 2 9 .

10.

1952,

ORNL-

PERIOD ENDING MARCH 1 0 , 1 9 5 3 a b s o l u t e p r e s s u r e o f 100 mm Hg, w h i c h c o r r e s p o n d s t o a sodium b o i l i n g tempera t u r e o f 1 2 8 5 " F , was s e l e c t e d f o r t h e distillation.

A f t e r some i n i t i a l d i f f i c u l t y with gas l e a k s , s e v e r a l 5 - l b b a t c h e s o f NaK were d i s t i l l e d , and t h e f o l l o w i n g o b s e r v a t i o n s were made: 1. T h e r e w a s n o d i f f i c u l t y i n c o m p l e t e l y d i s t i l l i n g t h e NaK. 2. Most o f t h e d i s t i l l a t i o n o c c u r r e d i n one s u r g e i n e a c h o f t h e f o u r r u n s , and a p a r t o f t h e c o n d e n s e r was h e a t e d t o almost t h e d i s t i l l i n g p o t temperature.

3. T h e a d j u s t a b l e p r o b e ( a p r o b e w i r e d t h r o u g h a s t u f f i n g box of s i 1i c o n e - r u b b e r '' w a s h e r s ") w o r k e d e x c e l l e n t l y , and gave r e p r o d u c i b l e l e v e l r e a d i n g s t h a t checked t o w i t h i n 1 / 3 2 i n . or c l o s e r .

NaK h a s b e e n d i s t i l l e d f r o m ARE pump l o o p , b u t b e c a u s e o f e x c e s s i v e o x i d a t i o n o f t h e t y p e 316 s t a i n l e s s s t e e l i n t h e l o o p , a s u f f i c i e n t l y low p r e s s u r e c o u l d n o t be m a i n t a i n e d on

t h e s y s t e m f o r a good t e s t o f t h e efficiency of the d i s t i l l a t i o n process t o be o b t a i n e d .

P o c k e t s o f NaK r e mained i n some o f t h e t r a p s , p a r t i c u l a r l y t h e pump.

In the Inconel ARE s y s t e m , s u c h c o r r o s i o n s h o u l d n o t be encountered; hence, e s s e n t i a l l y c o m p l e t e r e m o v a l o f NaK by d i s t i l l a t i o n s h o u l d be e f f e c t e d .

Flame Tests f o r N a K Vapor i n Helium ID. R, W a r d , A N P D i v i s i o n ) . T e s t s a r e being conducted t o determine t h e r e l i a b i l i t y o f flame t e s t s f o r cletecti n g t h e p r e s e n c e o f NaK i n h e l i u m . One m e t h o d u s e d was t o i n t r o d u c e h e l i u m , f r o m t h e s y s t e m f r o m w h i c h NaK w a s b e i n g r e m o v e d by t h e d i s t i 1IL a t i o n process, i n t o an otherwise c o l o r l e s s hydrogen flame; t h e b r i g h t n e s s o f t h e r e s u l t i n g f l a m e was t h e n m e a s u r e d by a p h o t o t u b e c i r c u i t , The r e s u l t s o f s i x t e s t s i n d i c a t e t h a t t h i s method may be used t o determine the degree of c l e a n l i n e s s o f a s y s t e m from w h i c h NaK h a s b e e n r e m o v e d by t h e d i s t i l l a t i o n method.

37

i 3.

REACTOR PHYSICS

W. K. E r g e n ,

ANP

Division

I

From t h e s t a n d p o i n t o f t h e p h y s i c s o f n u c l e a r r e a c t o r s , t h e main e v e n t d u r i n g t h e p a s t q u a r t e r was t h e c o r r e l a t i o n b e t w e e n t h e IBM m u l t i g r o u p c a l c u l a t i o n s and t h e c r i t i c a l e x p e r i ment on a f a i r l y r e a l i s t i c , r e f l e c t o r m o d e r a t e d , r e a c t o r mockup.

Because of the approximations involved i n t h e c a l c u l a t i o n s , it previously had n o t b e e n c l e a r how c l o s e t h i s c o r r e l a t i o n would be.

That t h e experimental c r i t i c a l mass t u r n e d o u t t o be o n l y s l i g h t l y h i g h e r t h a n t h e computed v a l u e and w a s w e l l w i t h i n t h e l i m i t s a c c e p t a b l e w i t h r e s p e c t t o uranium i n v e s t m e n t and f u e l c h e m i s t r y , c o n s t i t u t e s a m i l e s t o n e i n t h e development o f t h i s type of r e a c t o r .

Furthermore, t h e r e was, e x c e p t a t t h e b o u n d a r i e s , good c o r r e l a t i o n b e t w e e n t h e c o m p u t e d and t h e measured f l u x .

This applies t o t h e f l u x d i s t r i b u t i o n i n s p a c e and i n energy, but t h e only experimental i n d i c a t i o n s o f t h e energy d i s t r i b u t i o n a r e t h e t h e r m a l v a l u e and t h e cadmium r a t i o , which a r e e f f e c t i v e l y o n l y two p o i n t s on t h e e n e r g y d i s t r i b u t i o n

I

I

I

i

I I I

curve.

Some s i g n i f i c an t d i s c r e p a n c i e s exist a t the boundaries, but the s i m p l e d i f f u s i o n t h e o r y employed i n t h e c a l c u l a t i o n s o b v i o u s l y c a n n o t be expected to hold a t the interfaces between widely d i f f e r e n ' t m a t e r i a l s .

The n u c l e a r s t u d i e s p e r t i n e n t t o t h e reflector-moderated reactor are included i n sec. 4, "Reflectorhl od e r a t e d C i r cu 1a t i n g- Fu e 1 Re a c t o r

.

A s t o r e a c t o r k i n e t i c s , it w a s shown t h a t t h e d e l a y e d n e u t r o n s i n t r o d u c e damping o f r e a c t o r power o s c i l l a t i o n s , even i n t h e case of l a r g e i n i t i a l amplitudes, and, f u r t h e r more, one t y p i c a l example i n d i c a t e s t h a t t h i s damping d o e s n o t i n t e r f e r e d e s t r u c t i v e l y with t h e damping c a u s e d by f u e l c i r c u l a t i o n . A l s o , t h e (damping c a n be d e m o n s t r a t e d i n a t y p i c a l c a s e i n which t h e power and f l u x var.y a l o n g t h e path of a c i r c u l a t i n g f u e l .

The t e c h n i q u e s employed a r e v e r y s i m i l a r t o those reported in the previous ANP q u a r t e r l y r e p o r t s and a r e t h e r e f o r e n o t repeated here.

_

II. =

39

4.

REFLECTOR-MODERATED CIRCULATING-FUEL REACTORS A. P. F r a a s , ANP D i v i s i o n C. B. Mills, ANP D i v i s i o n A.D.Callihan,

Physics Division

Homogeneous r e a c t o r s a r e t h e m o s t simple nuclear reactors with respect t o i n t e r n a l s t r u c t u r e because t h e r e a r e no s t r u c t u r a l elements i n the reactor core.

Although t h e considerable experience achieved with liquid fluoride fuels indicates that they do n o t lend themselves t o the d e s i g n o f s m a l l , homogeneous r e a c t o r s because of t h e i r poor moderating p r o p e r t i e s , i t h a s been shown t h a t , by u s i n g t h i c k and e f f i c i e n t r e f l e c t o r s , i t is possible t o design a small, f l u o r i d e - f u e l r e a c t o r t h a t w i l l be r e l a t i v e l y f r e e o f s t r u c t u r a l com plexities.

Further, the combination of such a r e a c t o r with a s p h e r i c a l s h e l l h e a t e x c h a n g e r would p r o v i d e a r e a c t o r , h e a t exchanger, and s h i e l d p a c k a g e t h a t would be much s m a l l e r a n d l i g h t e r t h a n a n y r e a c t o r now b e i n g considered f o r the nuclear propulsion of a i r c r a f t .

T h i s s e c t i o n s u m m a r i z e s t h e work r e c e n t l y c a r r i e d o u t on t h i s t y p e o f power p l a n t .

The f i r s t p a r t c o v e r s t h e work d o n e on t h e s t a t i c p h y s i c s o f t h e r e a c t o r , i n c l u d i n g t h e e f f e c t on t h e r e a c t o r o f c o r e s i z e and t h e u s e of v a r i o u s m a t e r i a l s i n t h e c o r e and r e f l e c t o r . The s e c o n d p a r t p r e s e n t s t h e r e s u l t s o f tke c r i t i c a l e x p e r i ments and c o r r e l a t e s them w i t h t h e multigroup calculations.

The t h i r d p a r t covers t h e mechanical design e n v i s i o n e d and t h e d e v e l o p m e n t a l work i n i t i a t e d t o provide a basis f o r the detailed designof afull-scale reactor, The f o u r t h p a r t c o v e r s t h e s h i e l d i n g work t o d a t e , and t h e l a s t p a r t p r e s e n t s some p o s s i b l e f u l l - s c a l e a i r c r a f t power p l a n t a r r a n g e m e n t s , i n c l u d i n g e n g i n e s and r a d i a t o r s .

-

(I'D. K . Holmes, The M u l t i g r o u M e t h o d a s U s e d b y t h e ANP P h y s i c s C r o u p , ANP-58 [Feb. 1 5 , 1 9 5 1 ) .

STATIC PHYSICS

C. B. M i l l s , ANP D i v i s i o n The m o s t s i m p l e r e f l e c t e d r e a c t o r i s a s m a l l s p h e r e o f f i s s i o n a b l e mat e r i a l s u r r o u n d e d by a c o n c e n t r i c sphere of moderating material.

The f a s t neutrons leave the fuel-bearing r e g i o n e a s i l y and d i f f u s e i n t o t h e reflector.

I f the reflector is r e l a t i v e l y t h i c k and does n o t c a p t u r e the e s s e n t i a l l y thermalized neutrons, t h e c h a i n r e a c t i o n c a n be s u p p o r t e d because of the s u f f i c i e n t l y g r e a t p r o b a b i 1 i t y t h a t t h e 1 ow - e n e r g y n e u t r o n s w i l l d i f f u s e back i n t o t h e central fuel-bearing region.

The f i s s i o n c r o s s s e c t i o n , as w e l l a s t h e other cross sections in the fuel region, is s o high t h a t the slow neutrons r e - e n t e r i n g t h e r e a c t o r cannot e a s i l y re-escape.

T h i s r e a c t o r has been b r i e f l y evaluated with r e s p e c t t o moderator, f u e l , and g e o m e t r y e f f e c t s t o o b t a i n a qualitative understanding of neutron d i f f u s i o n and l o s s .

The a n a l y s i s i n v o l v e d t h e u s e o f t h e ORNL-ANP m u l t i g r o u p m e t h o d , ( ' ) s u p p o r t e d by c r i t i c a l experiments.

Neutron d i f f u s i o n i n a r e f l e c t o r m o d e r a t o r c a n be m o s t e a s i l y d e s c r i b e d by r e f e r r i n g t o t h e r e s u l t s o f t h e f i r s t multigroup calculation for a 3 2 - i n . - d i a f u e l r e g i o n s u r r o u n d e d by a 12-in. - t h i c k beryllium oxide r e f l e c t o r .

F i g u r e 4.1 shows t h e l e a k a g e s p e c t r u m a s a function of l e t h a r g y f o r neutron l e a k a g e from t h e c e n t r a l f u e l - b e a r i n g region i n t o the r e f l e c t o r .

The n e t c u r r e n t i s v e r y h i g h a c r o s s t h e boundary f o r high-energy (low-lethargy) neutrons.

M o s t o f t h e f i s s i o n n e u t r o n s move immediately i n t o t h e r e f l e c t o r , where they a r e moderated t o thermal energy.

41

ANP PROJECT QUARTERLY PROGRESS REPORT m

a

DWG. (8746

0.25

i

0.20

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z -I

0.15

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z

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W W

3 W

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18

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LETHARGY, u

Fig.

4.1.

Leakage Spectrum t o R e f l e c t o r v s . Lethargy.

They t h e n e i t h e r d i f f u s e back i n t o t h e fuel region, since the fuel region a t the center is a sink for thermal n e u t r o n s , or o u t o f t h e r e a c t o r a c r o s s t h e o u t e r r e f l e c t o r boundary.

F i g u r e 4.2 shows t h e s p a t i a l d i s t r i bution of neutrons a t t h r e e l e t h a r g i e s .

The t h e r m a l f l u x i s v e r y h i g h i n t h e nonabsorbing beryllium oxide r e f l e c t o r .

The l e t h a r g y d i s t r i b u t i o n o f f i s s o n i n g a b s o r p t i o n s and n e u t r o n e s c a p e f o r a n assumed n e u t r o n s o u r c e d i s t r i b u t i o n

42

4 . 3 ) i s g i v e n o n F i g s . 4.4 a n d Intermediate lethargy f i s s i o n i n g p r o c e s s e s a r e i m p o r t a n t , b u t 50% o f t h e f i s s i o n s r e s u l t s from t h e r m a l neutrons streaming i n to the c e n t r a l r e g i o n from t h e r e f l e c t o r , The e s c a p e s p e c t r u m , which is i m p o r t a n t f o r t h e r e a c t o r s h i e l d , shows t h a t a v e r y s m a l l f r a c t i o n o f f a s t n e u t r o n s e s c a p e s from t h e r e f l e c t o r , The r e l a t i v e v a l u e s o f fast-neutron escape through a 1-in.t h i c k l a y e r of boron c a r b i d e f o r a (Fig.

4.5.

-

PERIOD ENDING MARCH 1 0 , 1 9 5 3

60 0

al

p 55 ro

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LL.

w 40

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35

3

30

0 W

w

2

25

z

a cz 20

2

2

15

1 LL

5

10

E l-

2

z

5 0 0

2

4

6

8

10

12

14

76

18

20

22

24

26

28

30

32

34

36

SPACE POINTS, n ( r-2.14 n , c m )

Fig. 4.2.

Neutron Flux D i s t r i b u t i o n f o r Three Lethargy V a l u e s .

be r y 11ium re f 1e c t o r -moader a t e d r e a c t or a s compared w i t h a r e a c t o r w i t h a 6 in. -thick beryllium oxide r e f l e c t o r a n d a m o d e r a t i n g c o r e a r e shown i n Fig. 4.6.

The f a s t e s c a p e is even s m a l l e r f o r some o f t h e s u b s e q u e n t reflector-moderated reactor designs d e s c r i bed be 1ow.

I n summary, t h e n e u t r o n s a r e b o r n i n the c e n t r a l r e g i o n , spend t h e major a r t of t h e i r l i f e i n t h e r e f l e c t o r , nd, a f t e r moderation, d i f f u s e i n t o and o u t of t h e f u e l - b e a r i n g r e g i o n .

The prompt-neutron l i f e t i m e i s a b o u t 2 x sec, which i s a r e l a t i v e l y high value.

There i s a p o s i t i v e component i n t h e temperature c o e f f i c i e n t o f rea c t i v i t y of t h i s r e a c t o r because there i s s e l f - s h i e l d i n g o f t h e f u e l and a

p a r t o f t h e f i s s i o n s i s c a u s e d by f a s t n e u t r o n s i n t h e â&#x20AC;&#x153; D o p p l e r - r e g i o n . â&#x20AC;? The p o s i t i v e component a r i s e s b e c a u s e t h e i n c r e a s e d thermal motion o f t h e U235 a toms e f f e c t i ve l y b r o a d e n s and f 1a t t e n s o u t t h e resonance peaks i n t h e f i s s i o n cross sections, particularly those peaks i n the high-neutron-(energy region.

This decreases the selfshielding with respect t o neutrons of energies corresponding t o the peaks and i n c r e a s e s t h e r e a c t i v i t y .

T h e o r e t i c a l e s t i m a t e s and c : r i t i c a l experiments have t h u s f a r f a i l e d t o g u a r a n t e e t h a t t h i s p o s i t i v e component of the temperature coefficient of r e a c t i v i t y i s s m a l l compared w i t h t h e n e g a t i v e component e x p e c t e d from t h e f u e l e x p a n s i o n . However, t h i s r e a c t o r i s no w o r s e w i t h r e s p e c t t o t h e ]Doppler

43

ANP PROJECT QUARTERLY PROGRESS REPORT 4EeRN

DWG. 487f8 2.2

+#$ W

2.0

a:

s LL

1 .8

0 rn

1.6

a W

a 0

1.4

W 0

3

n

g

1.2

a v)

5

1.0

-

a:

+ 3

-

0.8 LL

0

E

I

0.6

m 3

ASSUMED

I

I

&CALCULA~

3

0.4

0

2

4

6

8

Fig. 4.3.

10

12 14 16 SPACE POINT, n

20

22

24

26

28

S p a t i a l Power D i s t r i b u t i o n .

temperature c o e f f i c i e n t of r e a c t i v i t y than the other reactor being studied, A s m a l l amount o f U 2 3 8 , a d d e d t o t h e fuel or placed i n the structure near t h e f u e l , would compensate f o r a p o s i 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 , because with U238 i t i s the absorption t h a t i s s e l f - s h i e l d e d , and t h e d e c r e a s e i n t h e s e l f - s h i e l d i n g with increasing t e m p e r a t u r e would r e d u c e t h e r e a c t i v i t y , V e r y low a b s o r p t i o n a n d v e r y good m o d e r a t i o n m u s t be o b t a i n e d i n t h e reflector, Structural material a t the core-reflector interface should a l s o h a v e a low a b s o r p t i o n c r o s s s e c t i o n , although the importance of the c r o s s s e c t i o n a t t h e i n t e r f a c e i s r e d u c e d by the small probability of several thermal-neutron t r a n s i t s because of

44

18

t h e h i g h a b s o r p t i o n and low a l b e d o o f the fuel region, T h e s t r u c t u r a l mat e r i a l i n the fuel-bearing region w i l l compete w i t h t h e uranium f o r t h e r m a l neutrons, Reactors w i t h Various R e f l e c t o r Moderators.

Computations have been made f o r a number o f p o s s i b l e r e a c t o r c o r e s i z e s and r e f l e c t o r - m o d e r a t o r compositions, and t h e r e s u l t s a r e summarized i n t h e f o l l o w i n g : 1. T h e l e a k a g e o f f a s t n e u t r o n s from t h e r e f l e c t o r a s a f u n c t i o n o f t h e slowing-down power, of the r e f l e c t o r i s shown i n F i g . 4 . 7 .

A f a c t o r of 1/5 i n results in a f a c t o r o f 400 i n t h e t o t a l e s c a p e o f f a s t neutrons , t h a t is , neutrons with l e t h a r g i e s s m a l l e r t h a n 4. F i g u r e 4 . 8

ex,,

exs

.

PERIOD ENDING MARCH 1 0 , 1 9 5 3 SEGREF 18719

DWG. m

z

8 5 W z

-I

ez

aQ

5

0.07

a

$ 0.06 c a

E

005

w

-I

z

3

6 a v)

z Q

v,

004 0.03

0.02 0.01

LL

0 LETHARGY, u

Fig. 4.4.

F i s s i o n Spectrum v s . L e t h a r g y . !@EW€F DWG. 18720

LETHARGY, u

pectrum to S h i e l d v s . L e t h a r g y . shows t h e r e f l e c t o r t h i c k n e s s f o r a g i v e n n e u t r o n c u r r e n t e s c a p i n g from the r e f l e c t o r as a function of the moderating p r o p e r t i e s of the r e f l e c t o r m a t e r i a l . These p r o p e r t i e s a r e charac-

t e r i z e d by t h e a g e - t o - t h e r m a l i n t h e reflector material.

2.

The a b s o r p t i o n i n t h e r e a c t o r f u e l i s s e n s i t i v e t o t h e slowing-down p o w e r , c X s , o f t h e r e f l e c t o r only f o r

45

A N P PROJECT QUARTERLY PROGRESS REPORT

4.8X l0l2

-0

4 4 4.0

v)

N

eE

3.6

c

-c

3.2

a 13

5 LL LL

2.8 2.4

0

0'

2.0

c U

az

1.6

1.2

0.8 0.4 X40'z

0 LETHARGY,

Fig.

4.6.

-

C o m p a r i s o n o f t h e N e u t r o n C u r r e n t f r o m _Two_Reactors

poor moderators, The a b s o r p t i o n decreases rapidly for < 0.08 ( F i g .

4.9) 3. The e s c a p e s p e c t r u m v s . l e t h a r g y i s shown i n F i g . 4 . 1 0 f o r t h e two b e s t r e f l e c t o r s , b e r y l l i u m and b e r y l l i u m o x i d e . The d i f f e r e n c e s i n t h e s p e c t r a a r e c h a r a c t e r i s t i c of the differences i n t h e c r o s s s e c t i o n s and t h e m o d e r a t i n g power o f t h e two m a t e r i a l s . B e r y l l i u m i s a much b e t t e r r e f l e c t o r mat e r i a l than beryllium oxide.

4. The e f f e c t o f r e f l e c t o r m a t e r i a l a n d t h i c k n e s s on t h e e s c a p e o f f a s t n e u t r o n s i s shown i n F i g . 4 . 1 1 .

In order of desirability, the materials are: beryllium, beryllium oxide, 6 in. of beryllium plus 6 in. of carbon, beryllium oxide aggregate, 4 i n . of b e r y l l i u m p l u s 8 i n . of carbon, and c a r b o n . NaOD i s a good r e f l e c t o r o n l y with regard t o neutron escape.

The c r i t i c a l mass w i t h a NaOD r e f l e c t o r i s h i g h ( 6 0 l b ) b e c a u s e o f t h e sodium absorption.

46

U

-_

5.

The e f f e c t o f t h e m o d e r a t o r i n d i c a t e s t h a t there is l i t t l e dep e n d e n c e o f t h e p o w e r d i s t r i b u t i o n on the reflector material in a simple s y s t e m . The p r e s e n c e o f s t r u c t u r e a n d the e f f e c t of operating temperature a r e expected t o favor beryllium a s the reflector-moderator, ifaminimum r a t i o o f p e a k - t o - a v e r a g e power d e n s i t y i s t o be o b t a i n e d , 6.

The e f f e c t o f r e f l e c t o r t h i c k n e s s on r e a c t i v i t y ( F i g . 4 . 1 2 ) s h o w s t h a t t h e b e r y l l i u m or b e r y l l i u m o x i d e r e f l e c t o r s m u s t be o v e r 1 0 i n . t h i c k b u t t h a t l i t t l e i s t o b e g a i n e d by e x c e e d i n g 16 i n , i n t h i c k n e s s .

Reactors with Beryllium ReflectorModerators.

The r e s u l t s g i v e n a b o v e , a s well as other 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 b e r y l l i u m i s t h e b e s t reflector-moderator. Several beryllium reflector-moderated reactors d i f f e r i n g i n s i z e and d e s i g n were s t u d i e d , a n d t h e r e a c t i v i t y c o e f f i c i e n t s were e s t i m a t e d . A l t h o u g h t h e numbers g i v e n

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 SremT DING. 1 8 7 2 2

W (3

a Y a

w

1

V

a

W

0

z 0

c z

W = I

W

a c

zI

0.01

3

a a

bl 2 0 W

+

a W

I-

s

g

0.001

0 0 I-

n W 3 -t

a

B

0

z 0.0001 0.2

0.1

0

0.3

â&#x201A;ŹE s Fig. 4 . 7 .

Down Power.

Total Neutron Leakage o f Fission-Energy Neutrons v s .

Slowing-

ueW3DWG. 18723

E l 0

c u

9

(L

W

F I

$0 5

-

I-

LL 0 0 7

9 2 + 2 0 0

100

200

300

4 00

0

01

FERMI AGE (cm2)

Constant-Fast Neutron Leakage v s . Aget o - Thermal o f the R e f l e c t o r .

Fig. 4.9. the F u e l v s .

02

=,

03

04

Neutron A b s o r p t i o n i n Slowing-Down Power.

47

ANP PROJECT QUARTERLY PROGRESS REPORT BEGReF DWG. t 8725

19

18

17

16

15

14

13

12

10

11

9

8

7

6

5

4

3

2

1

0

LETHARGY, u

Fig. 4.10.

Beryl 1 ium.

N e u t r o n Escape Spectrum t o t h e S h i e l d f o r B e r y l l i u m O x i d e and

below r e f e r t o t h e s p e c i f i c r e a c t o r s considered, the general conclusions a r e b e l i e v e d t o be v a l i d f o r a v a r i e t y of reflector-moderated r e a c t o r s , 1. The r a t i o o f t h e p e a k - t o - a v e r a g e power d e n s i t y c a n be d e c r e a s e d by r e p l a c i n g t h e c e n t r a l volume o f t h e f u e l w i t h a moderator. The r a t i o o f t h e p e a k - t o - a v e r a g e power c a n be r e d u c e d t o about 1 . 3 , and t h e c r i t i c a l mass c a n be r e d u c e d t o a b o u t 1 / 2 t h e c o r r e s ponding value f o r a comparable r e a c t o r without a center island.

2. The e f f e c t o f c h a n g e s i n v a r i o u s components on t h e r a t i o o f p e a k - t o a v e r a g e power d e n s i t y i s o f i n t e r e s t .

For a b a s i c d e s i g n , i n which t h e d i ameters of central moderator, fuel r e g i o n , and r e f l e c t o r were 1 4 , 2 2 , a n d 4 6 i n . , r e s p e c t i v e l y , a n d t h e r e was 2 . 8 v o l % I n c o n e l i n t h e NaF-UF4 f u e l c o o l a n t ( t o s i m u l a t e s t r u c t u r e between

48

fuel and r e f l e c t o r ) , the r e l a t i v e c h a n g e s a r e i n d i c a t e d by t h e f r a c t i o n s g i v e n below.

The d e n o m i n a t o r i s t h e f r a c t i o n a l change i n the parameter noted, The numerator refers t o t h e r a t i o o f t h e p e a k power d e n s i t y t o t h e a v e r a g e power d e n s i t y a n d r e p r e s e n t s t h e f r a c t i o n a l change o f t h i s r a t i o c a u s e d by t h e c h a n g e i n d i c a t e d i n t h e denominator.

PARAMETERS

Amount of U235 i n the fuel

--- 4Qh

0.34

@/P =

-0.117

@â&#x20AC;? = 0.16

&/M

Fuel layer thickness Structure weight fraction Radius of central moderator

@/p AT/T @/P -

&/R

-0.067

PERIOD ENDING MARCH 1 0 , 1 9 5 3 bnmr OWG 18726

10-1

I

I

I

I

I

I

I

I I

I

1

!'',I

I I

I

I

I

1

I

CARBON

k

I

I

I I

I

I

I I

I I

I

I

!

I

I

,

I

I

I

I

I

I

I

2

The computed v a l u e s o f p e a k - t o - a v e r a g e power d e n s i t y a t t h e two s i d e s a n d a t the center of the fuel-coolant region a r e t a b u l a t e d i n Table 4.1.

3. The r e a c t i v i t y c o e f f i c i e n t s o f d e s i g n i n t e r e s t a r e , where p i s d e n s i t y , M is w e i g h t , and T i s t h i c k n e s s :

10-2 d

For core s t r u c t u r e ,

V y

5

0 W-

3

For fuel layer thickness,

2

W

$10-3

For beryllium r e f l e c t o r ,

k-

W

L

- @k/k -

&/T

b / k

-0.17

;

=

0.52

;

-

0.22

;

4??P

5

2

For UZJs content, 2

For NaF coolant,

I 0-4

5

\ 2

\

IO-^ 0

4

8

Fig. 4.11.

12 16 REFLECTOR THICKNESS (in)

20

F a s t - N e u t r o n Leakage

v s . R e f l e c t o r Thickness. ii.5HeY D W G . 48727

tC

I REFLECTOR 1201

a

-to +O

20

REFLECTOR THICKNESS (in)

Fig. 4.12.

Effect of Reflector Thickness on M u l t i p l i c a t i o n Constant.

-&/i4

-=W

k 4O/P

0.106

.

4. The s u b s t i t u t i o n o f 6 or 8 i n . of carbon f o r beryllium i n t h e ref l e c t o r i n c r e a s e s t h e c r i t i c a l mass by 15 a n d 25%, r e s p e c t i v e l y .

5 . Most o f t h e s t r u c t u r a l m a t e r i a l s t h a t m i g h t be u s e d b e t w e e n t h e f u e l and moderator have a h i g h a b s o r p t i o n c r o s s s e c t i o n , a n d t h e r e f o r e some o f t h e t h e r m a l n e u t r o n s coming from t h e r e f l e c t o r a r e absorbed, The l o s s o f a l l t h e t h e r m a l n e u t r o n s would i n c r e a s e t h e c r i t i c a l mass by a f a c t o r o f a t l e a s t 10.

A 1/4-in.-thick layer of Inconel might r e s u l t i n a r e a c t i v i t y loss o f a s much a s 0 . 2 4 , w h i c h i m p l i e s a n i n c r e a s e i n c r i t i c a l mass o f t h e o r d e r o f 100%.

6. A n e g a t i v e c o m p o n e n t o f t h e temperature c o e f f i c i e n t of r e a c t i v i t y i s o b t a i n e d from t h e t h e r m a l e x p a n s i o n o f t h e f u e l , f o r two r e a s o n s : (1) t h e loss of scattering centers for f a s t n e u t r o n s a n d ( 2 ) t h e l o s s o f f u e l from t h e a c t i v e volume, I f an e x p a n s i o n c o e f f i c i e n t f o r t h e f u e l o f 2 x 10'4/0F i s assumed, t h e temperature coeff i c i e n t s r e s u l t i n g f r o m t h e s e two e f f e c t s a r e , r e s p e c t i v e l y , 0.2 x 1 0 ' 4 / 0 F a n d 0.4 x 10'4/0F, a t o t a l o f 0.6 X 10'4/0F. The f i r s t o f t h e s e r e a c t i v i t y c o e f f i c i e n t s is s m a l l e r f o r some o t h e r r e a c t o r s ( f o r e x a m p l e , t h e 49

TABLE 4 . 1 .

vl

S T A T I C P H Y S I C S OF SEVERAL REFLECTOR-MODERATED REACTOR D E S I G N S

4 z 71

0

___ ~

FUEL Outside )iameter (in.)

GION Inside Dimeter (in. 1

22

14

~

REACTOR TYPE

103 121 124

117

I18 119 120

REFLECTOR ( 1 f t thick)

REA1 CRITICAL

MASS

THERMAL FISSIONS

(Ib )

(5)

60

40

YaOD

3irculating 1str.). 3 regions Circulating (str.), 3 regions Circulating (str.). 3 regions Circulating (St..).

3 regions

fuel

3e(Na c o o l e d )

22

14

14.8

fuel

3e(Na c o o l e d )

19

11

12

fuel

Be(Na c o o l e d )

22

11

17

fuel

Be(Na c o o l e d ) . 1 6 in. thzck

22

14

14

22

k1Na cooled)

19

9

@(OF)

C i r c u l a t i n g fuel, 3 regions Circulating fvel (str.(C)), 2 regions Fuel p l a t e s (Na cooled). 3 regions

h ( N a cooled)

Thermal Base Ah/k

9.6

45

10.6

x

17

38

7.5

x

59 58

UZ3’ Mass Ak/k __ M / M

POWE1 __ Ak/k

Inside Peak-

IENSITY lu t s i d e Peak-

to-

to-

OB(0F)

herage

herage

S O v e r - a1 1

)

~

1.26

0.20

x

25

VITY MEFFICI

0.20 10-6

-7 x 10-1

0.25

~

1.16

2.16

0.52

1.19

1.59

’10s MiniTOTAL mumIEUTRMY toESCAPE Average

___ 0.90

0.75

0.335

0.000328

x

0.26

1.14

1.29

0.85

0.303

0.000280

x

0.25

1.15

1.29

0.86

0.222

0.0000149

8.7

x 10-6

0.30

1.14

1.28

0.86

0.308

0.00029

1.95

0.50

0.447

0.0043

52

6.9

13

60

11.5

9

65

-8

10”

Be0

16

22

28

4.4

x 10-6

0.27

-7 x 10-s

Be0

32

18.5

53

-2.1

x 10-6

0.47

-12 x 10-5

1.71

0.60

Be0

22

14

9.4

60

-0.5

x 10-6

0.30

-8 x 10.’

1.10

1.30

0.85

Be0

48

24

160

40

1.4

x 10-6

2.34

2.11

0.55

Be0

22

14

35

40

1.9

X

0.20

1.21

1.69

115

Circulating fuel, 3 regions

Be0 q g r e g a t e

22

14

35

30

7

x 10-6

0.20

1.07

102

Circulating fuel, 3 regions C i r c u l a t i n g fuel (str.), 3 regions C i r c u l a t i n g fuel, 2 regions

C

32

20

33

40

-17

X

0.20

C-Be ( h i g h p )

22

14

13

57

6.5

X

0.56

Be(4 i n . ) C(8 i n . )

16

31

38 35

4.08

X

0.20

Circulating fuel.

2 regions C i r c u l a t i n g fuel (st=.). 3 regions

B e ( 6 in. ) C(6 i n . )

16

1.01

Y.

Be(Na c o o l e d )

19

8

23

47

137

C r i t i c a l experiment, 20-mi1 f o i l and sodium cans, 3 r e g i o n s

Be

16

10

30

47

10.0

140

R-118 w i t h p(NaF)

Be(Na c o o l e d )

19

11

15

56

10.5

128 129

X

1/2, 3 regions

25.5

X

0.345

0.0020

0.190

0.0025

0.71

0.352

0.0029

1.21

0.90

0.473

0.01037

1.3

1.2

0.90

0.450

0.040

1.15

1.29

0.86

0.297

0.00167

1.86

0.52

0.488

0.010744

1.93

0.49

0.440

0.00436

0.92

1.75

0.65

0.343

0.000501

x 10-6

1.27

1.00

0.87

0.367

0.001191

X

0.96

1.34

0.83

0.343

0.0003866

10-6

0.20

8.02 x 10-6

0.16

-9 x 10.’

-5 x 10-1

-4 x 10-5

-

( a ) D o e s n o t i n c l u d e t h e Doppler e f f e c t . ( b ) T h r o u g h 1 i n . o f boron c a r b i d e . ( “ I n t h e s e c a l c u l a t i o n s , s t r u c t u r e was added t o t h e f u e l t o s i m u l a t e s t r u c t u r e b e t w e e n f u e l and moderator.

.

=a 4

0.85

C i r c u l a t i n g fuel, 2 regions Cirevlating fuel.

2 regions C i r c u l a t i n g fuel.

3 regions C i r c u l a t i n g fuel ( a i r cooled), 3 region.

F u e l plates (Ne cooled), 3 regions

127

C

- -

4

ro

1.29

95

122

0.0002596

1.14

22

108

0.264

0.27

x

Be(Na c o o l e d )

109

0.299

0.000291

17.6

m

n

0.0002996

0.299

-8 x lo-’

h

0.00228

0.83

0.42

71 s 0

0.397

1.35

x

Circulating fuel, 3 regions

101

~

1.18

6.5

105

97

ESCAPE OF FAST NEUTRONS( ) 10.2 t o 10 Me”)

4

m rxl r

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 ARE) by a f a c t o r o f 1 0 , b u t t h e s e c o n d i s a p p r o x i m a t e l y t h e same.

7. The mean l i f e t i m e o f t h e p r o m p t n e u t r o n s i s about 4 x l o e 4 sec f o r t h e beryllium-reflected reactor with a center island.

About 1/2% o f t h e prompt n e u t r o n s h a s a mean l i f e t i m e o f t h e o r d e r o f lo’* s e c b e c a u s e o f t h e low a b s o r p t i o n and l e a k a g e p r o b a b i l i t y i n the reflector.

8. A c o o l i n g s y s t e m m u s t b e p r o vided f o r the moderator because of gamma and n e u t r o n h e a t i n g ; a b o u t 4% o f t h e t o t a l power a p p e a r s i n t h e m o d e r a t o r volume.

I n s e r t i o n of such a system means an i n c r e a s e d amount o f s t r u c t u r e i n the r e f l e c t o r , which, i n t u r n , c a u s e s a l o s s i n r e a c t i v i t y and a g a i n i n gamma-ray i n t e n s i t y .

T h i s problem i s being studied.

9. One a s p e c t o f i m p o r t a n c e f r o m t h e s h i e l d i n g standpoint is t h e energy s p e c t r u m o f t h e n e u t r o n s e s c a p i n g from both t h e s u r f a c e of t h e t h i c k r e f l e c t o r and t h r o u g h t h e f u e l - c i r c u l a t i o n passages a t the r e a c t o r ends.

This s p e c t r u m is s t r o n g l y t h e r m a l f o r t h e r e f l e c t o r s of i n t e r e s t .

The a d d i t i o n of 1 i n . o f boron c a r b i d e a t t h e r e f l e c t o r boundary reduces t h e t o t a l leakage through the sides of the r e a c t o r t o the values l i s t e d i n Table 4 . 1 a s “ e s c a p e o f f a s t n e u t r o n s . ” The u s e of a n o n p o i s o n i n g , h e a v y m a t e r i a l ( l e a d o r bismuth) a s t h e r e f l e c t o r c o o l a n t may b e b e n e f i c i a l f r o m t h e s h i e l d i n g s t a n d p o i n t because i t should m o d e r a t e f a s t n e u t r o n s by i n e l a s t i c s c a t t e r i n g a n d a l s o s e r v e a s gamma shielding, The f a s t l e a k a g e through t h e f u e l p a s s a g e s and from f i s s i o n i n g p a s s a g e s must be m i n i m i z e d by i o n o f f i s s i o n a n d by t h e i o n of e x t r a s h i e l d i n g m a t e r i a l .

T h i s problem is n o t e a s i l y a d a p t a b l e t i o n , and h e n c e c r i t i c a l w i l l be p e r f o r m e d t o a l u a t e l e a k a g e con 10. A f e a s i b l e r or-moderated r e a c t o r c a n be b u i l t by r e p l a c i n g t h e c i r c u l a t i n g - f u e l c o o l a n t ( f o r example,

NaF-UF,) w i t h u r a n i u m - b e a r i n g s t a i n l e s s s t e e l f u e l p l a t e s and s o d i u m c o o l a n t .

A design incorporating t h i s feature h a s b e e n p r o p o s e d by A . S. Thompson.

Shim c o n t r o l f o r s u c h a r e a c t o r c a n be a c c o m p l i s h e d by v a r y i n g t h e c o n c e n - ‘ t r a t i o n o f p o t a s s i u m i n t h e sodium c o o l a n t . By t h i s m e a n s , t h e r e l a t i v e b u r n u p c o u l d be made v e r y l a r g e .

T h e s e r e s u l t s imply t h a t t h e goal o f a s i m p l e , s t r u c t u r e l e s s c o r e is i m p r a c t i c a l because t h e f u e l s o l v e n t is inadequate a s a moderator.

An i s l a n d of s o l i d moderator i n the c e n t e r of t h e c o r e seems t o be d e s i r a b l e , a n d t h e u s e f u l n e s s o f such an i s l a n d is n o t e n t i r e l y n u c l e a r , A s w i l l be shown l a t e r , the hydrodynamics of a reflector-moderated reactor are a l s o a i d e d by a c e n t r a l i s l a n d .

Summary T a b l e s and G r a p h s .

The m u l t i p l i c a t i o n c o n s t a n t s o f two- and three-region reflector-moderated r e a c t o r s a s a function of uranium weight i n the f u e l region f o r s e v e r a l c o r e and i s l a n d s i z e s and m o d e r a t o r compositions a r e given i n F i g . 4.13.

The v a r i o u s r e a c t o r s r e f e r r e d t q i n t h i s figure are described i n Table 4.1.

The f i g u r e s u m m a r i z e s a nhmber of point values for reactivity.

To facilitate the extrapolation, the c u r v e s drawn t h r o u g h p o i n t v a l u e s i n d i c a t e the manner i n which the multiplication constant varies with uranium weight f o r the p a r t i c u l a r r e a c t o r t o which the p o i n t value refers.

I f only two-region r e a c t o r s are considered, the shapes of the curves vary systematically with the position of the point value i n the uranium weight vs. k , f f p l a n e .

Hence, o n l y a few o f t h e c u r v e s were a c t u a l l y c o m p u t e d , and t h e o t h e r s were drawn by analogy.

L i k e w i s e , a few k e f f v s . u r a n i u m w e i g h t c u r v e s c a n be c o m p u t e d f o r three-region r e a c t o r s and then s i m i l a r c u r v e s c a n be drawn t h r o u g h the point values.

The s h a p e s o f t h e curves for three-region reactors a r e , of c o u r s e , d i f f e r e n t from t h o s e f o r

51

ANP PROJECT QUARTERLY PROGRESS REPORT SmRu D W G . 18728

. s

1.2

. * t .1

-I

p 0.0

I

52 H

I

SEE TABLE 4.1 FOR DESCRIPTION OF REACTORS BY NUMBER

tt5

0.7

0.6 U R A N I U M WEIGHT (Ib)

Fig.

4.13.

Uranium Weight v s . k e f

f o r Several Reflector-Moderated Reactors.

t h e two-region reactors.

(Threer e g i o n r e a c t o r s have c e n t e r i s l a n d s . ) The c u r v e s d e s c r i b e d a b o v e a r e n o t e x p e c t e d t o be e x a c t .

I t s h o u l d be n o t e d t h a t t h e IBM m u l t i g r o u p m e t h o d s t a r t s w i t h a n a s s u m e d power d i s t r i b u t i o n ; and, i f t h e c a l c u l a t i o n r e s u l t s i n a power d i s t r i b u t i o n d i f f e r e n t from t h e assumed o n e , a n i t e r a t i o n m u s t be made by u s i n g t h e c o m p u t e d d i s t r i bution as a start.

Such i t e r a t i o n s were c a r r i e d o u t o n l y where e s s e n t i a l .

Whenever p o s s i b l e , f u e l - c o o l a n t c o n s t i t u e n t s were h e l d c o n s t a n t t o e m p h a s i z e t h e e f f e c t s o f main i n t e r e s t .

I t i s t o be n o t e d t h a t a n y f u e l s e l f s h i e l d i n g or p o i s o n i n g e f f e c t , or a n y change i n r e a c t o r s i z e , is r e f l e c t e d by a r a p i d c h a n g e i n r e a c t i v i t y and a

52

r a p i d change i n t h e s l o p e o f t h e c u r v e s v s . u~~~ mass.

Of k e f f Typical r e s u l t s of the multigroup s o l u t i o n of t h e neutron d i f f u s i o n p r o c e s s e s a r e given i n Figs. 4.14 t o 4.17.

F i g u r e s 4.14 and 4.15 g i v e s p a t i a l power d i s t r i b u t i o n a n d f l u x s p e c t r a , r e s p e c t i v e l y , f o r one e x t r e m e case - a reactor with a small (8-in.d i a . ) , c e n t r a l , moderator r e g i o n , a thick (5 1/2-in.), fuel-bearingregion, and sodium-cooled f u e l p l a t e s .

The r e l a t i v e l y high peak-to-average r a t i o i n t h e power d i s t r i b u t i o n c u r v e , Fig. 4.14, emphasizes t h e v a l u e of a thin fuel layer.

F i g u r e s 4.16 and 4 . 1 7 g i v e t h e computed power and f l u x distribution for the f i r s t critical

*

PERIOD ENDING MARCH 1 0 , 1 9 5 3 -Rs+.

D W G. 'I 8 7 2 9

2.0

* W

a

1.8

8

E LI-

0

1.6

I

to

5 1.4

4

REACTOR 129 (SEE TABLE 4.1)

I

CK W

a w i.2 0

3

*NORMALIZED TO ONE SOURCE NEUTRON PER c m 3 OF CORE

n 0 CK

a

1.0

v)

2

0.8

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3 z LL

0.6

0

0.4 I 3

z I 0

I

2

4

I

6

I

8

I

I

i0 12 14 46 18 SPACE POINT, n ( r =nAr,crn)

20

22

24

26

28

Fig. 4.14.

S p a t i a l Power D i s t r i b u t i o n f o r a T h r e e - R e g i o n R e a c t o r w i t h a Thick Fuel Annulus.

e x p e r i m e n t c a l c u l a t i o n , f o r which 1by 3- by 3 - i n . s o d i u m - f i l l e d c a n s a n d 10-mil-thick] 3-in.-dia, U235 f u e l d i s k s were u s e d , A comparison w i t h t h e experimental r e s u l t s is given i n the next section.

r e f l e c t o r -mod e r a t e d c i r c u l a t i n g - f u e l r e a c t o r w a s d e s c r i b e d p r e v i o u s l y . ( 2, Some i n f o r m a t i o n a l r e a d y r e p o r t e d i s

repeated here t o g i v e a u n i f i e d picture of the first reflector-moderated reactor c r i t i c a l experiment.

The f u e l consisted of 0.020-in. -thick p i e c e s o f U 2 3 5 m e t a l lumped between 1-in. l a y e r s of sodium canned i n s t a i n l e s s steel.

This arrangement was shown t o be i n e f f i c i e n t i n n e u t r o n u t i l i z a t i o n because of the s e l f s h i e l d i n g i n t h e t h i c k uranium l a y e r s .

The s e l f - s h i e l d i n g o f t h e f u e l was m e a s u r e d e x p e r i m e n t a l l y by r e p l a c i n g one o f t h e 20-mil f u e l d i s k s w i t h 1 0 d i s k s t h a t were e a c h 2 m i l s ; t h i c k w i t h aluminum c a t c h e r f o i l s between them.

The a c t i v i t y o f t h e c a t c h e r f o i l s showed t h a t t h e 2 0 - m i l l a y e r s V. P. Williams, R. C. Keen, J. J. Lynn. and C. B. Mills, A N P Quar. P I - o g . R e p .

D e c . I O , 1952, ORNL-1439, p. 48.

("D.

D.

Scott,

53

a

ANP PROJECT QUARTERLY PROGRESS REPORT SeeRPT DWG. 1 8 7 3 0

0

2

4

6

8

10 12 14 16 48 20 22 SPACE POINT, n ( r - n A r , c m )

24

26

28

30

Fig. 4.15.

S p a t i a l F l u x D i s t r i b u t i o n f o r a T h r e e - R e g i o n Reactor w i t h a Thick Fuel Annulus. w e r e 66% e f f e c t i v e ; t h e c o r r e s p o n d i n g t h e o r e t i c a l e s t i m a t e was 63%.

The c r i t i c a l mass was f o u n d e x p e r i m e n t a l l y t o be 1 5 kg o f U 2 3 5 . With t h i s loading, a multiplication constant o f 1 . 0 3 was c a l c u l a t e d by t h e m u l t i g r o u p method. The u s u a l s e l f - s h i e l d i n g c o r r e c t i o n f o r t h e lumped f u e l was used.

The c a l c u l a t i o n was c a r r i e d out f o r a s p h e r i c a l shape, whereas t h e a c t u a l g e o m e t r y was r e c t a n g u l a r .

T h i s d i f f e r e n c e was a c c o u n t e d f o r by r e d u c i n g t h e f u e l volume f o r c a l c u l a t i o n p u r p o s e s by 10%. The c o m p u t a t i o n d i d n o t i n c l u d e any p o i s o n i n g e f f e c t of i m p u r i t i e s i n t h e m a t e r i a l s .

The n e u t r o n - f l u x t r a v e r s e s m e a s u r e d r a d i a l l y t h r o u g h t h e m i d - p l a n e of t h e r e a c t o r were given p r e v i o u s l y . (3) The a c t i v a t i o n s o f b a r e - and cadmiumc o v e r e d - i n d i u m f o i l s and t h e i r d i f f e r e n c e s w e r e shown.

These r e s u l t s a r e t y p i c a l of t h o s e o b t a i n e d a l o n g o t h e r t r a v e r s e s , and t h e y c o n f i r m t h e predictioh of high neutron flux in t h e m o d e r a t o r i s l a n d and r e f l e c t o r .

This e f f e c t is, a s expected, p a r t i c u l a r l y pronounced f o r t h e r m a l n e u t r o n s .

The cadmium f r a c t i o n , d e r i v e d f r o m t h e i n d i u m - f o i l a c t i v a t i o n d a t a and d e f i n e d a s t h e r a t i o of t h e a c t i v a t i o n (3)Zbid., F i g . 5 . 3 , p . 51.

I

54

P E R I O D ENDING MARCH 1 0 , 1 9 5 3

S

I

m

DWG. 18731

1 .6

1 .4

*

W

8

1.2

LL 0

*

t.0

5

a

E

0.8

W

u = I

0.6

0

$ a m

z 0.4 a 0 I-

3

y

0.2

LL

0

gm

0

5

2

0

2

4

6

8

10

12

(4

16

18

20

22

24

26

28

30

32

SPACE POINT, n ( r = n A r ,cm)

Fig. 4.16.

Assembly.

C a l c u l a t e d S p a t i a l Power D i s t r i b u t i o n f o r t h e F i r s t C r i t i c a l

by n e u t r o n s o f e n e r g y below t h e cadmium c u t - o f f t o t h e a c t i v a t i o n by a l l n e u t r o n s , was g i v e n p r e v i o u s l y . ( 4 ) T h e v a l u e s of t h i s cadmium f r a c t i o n , a s c a l c u l a t e d from t h e I B c o m p u t a t i o n s , were a l s o p l o t t e d .

T h e o r e t i c a l and e x p e r i m e n t a l v a l u e s p r a c t i c a l l y coincide i n t h e c e n t e r of t h e f u e l and i n t h e b u l k o f t h e reflector.

The d i s c r e p a n c y a t t h e f u e l s u r f a c e is n o t s u r p r i s i n g , s i n c e r a c t i c a l c a l c u l a t i o n methods, h e â&#x20AC;&#x153; a g e â&#x20AC;? m u l t i g r o u p method, c t n e a r boundaries. i o n i n g d i s t r i bu t i o n t h r o u g h u e l r e g i o n i s shown i n Fig. 4.18.

The e x p e r i m e n t a l v a l u e s are c a t c h e r - f o i l m e rements.

Since t h e m e a s u r e m e n t s were n o t n o r m a l i z e d ,

-

( 4 ) I b i d . , F i g . 5 . 5 , p . 53.

there is n o s i g n i f i c a n c e in t h e c l o s e agreement of the a b s o l u t e v a l u e s of t h e t h e o r e t i c a l and experimental curves.

H o w e v e r , t h e a g r e e m e n t in t h e p e a k - t o - a v e r a g e r a t i o s of p o w e r d e n s i t y d o e s seem s i g n i f i c a n t .

The discrepancy i n t h e shape of t h e c u r v e s i n s i d e t h e f u e l l a y e r c a n be a t t r i b u t e d t o t h e f a c t t h a t t h e r e i s more m o d e r a t o r i n the rectangular center island than was assumed i n t h e c o m p u t a t i o n based on s p h e r i c a l g e o m e t r y .

To d e t e r m i n e t h e r e a c t i v i t y l o s s expected from s t r u c t u r a l m a t e r i a l a t t h e c o r e - r e f l e c t o r i n t e r f a c e , an e x p e r i m e n t was p e r f o r m e d ( F i g . 4 . 1 9 ) w i t h o n e - h a l f of one of t h e f o u r o u t s i d e s u r f a c e s of t h e c o r e c o v e r e d with 1/4-in. s t a i n l e s s steel p l a t e s .

The loss i n r e a c t i v i t y was 220 c e n t s , which i s c o n s i s t e n t w i t h t h e t h e o r e t i c a l

55

ANP PROJECT QUARTERLY PROGRESS REPORT

20 -I

W

3

LL

ia

LL

0 m

16

E

0

U W

a

z 0 m v, LL W

z

14 12

10

0 U

2 X 3 -I

LL

a 6

z

0 U t-

4

3 W

z

2

0 0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

SPACE POINT, n ( r =1.757 n, cm)

F i g . 4.17.

C a l c u l a t e d F l u x S p e c t r u m f o r t h e F i r s t C r i t i c a l Assembly.

v a l u e o f 24%, f o r an I n c o n e l l a y e r o v e r both t h e i n n e r and t h e o u t e r fuel-reflector interfaces.

A 1 - i n . - t h i c k l a y e r of l e a d or bismuth a t t h e c o r e - r e f l e c t o r i n t e r f a c e ( w h e r e i t seems t o b e m o s t u s e f u l ) on one o f t h e four o u t e r s u r f a c e s of t h e c o r e c o s t 0.24% i n k c f f for bismuth and 0.91% f o r l e a d , a s compared w i t h a void.

Second C r i t i c a l Assembly.

A second assembly with f u e l p r o p e r t i e s t h a t more c l o s e l y r e s e m b l e t h o s e of a p o s s i b l e f u l l - s c a l e r e a c t o r was constructed.

I n t h i s second assembly, t h e f u e l was a mixture o f 66 w t % ZrO,, 2 4 w t % NaF and 1 0 w t % C ( t h e Zr0,-C combination simulates ZrF,), with s u f f i c i e n t e n r i c h e d UF, a d d e d t o make t h e U 2 3 5 d e n s i t y 0 . 2 g/cm3.

The w e l l - h o m o g e n i z e d p o w d e r m i x t u r e was p a c k e d i n 1 1 / 4 - i n . s q u a r e aluminum

56

t u b e s t h a t were a r r a n g e d a r o u n d t h e c e n t r a l b e r y l l i u m c o r e and w e r e , i n t u r n , s u r r o u n d e d by t h e b e r y l l i u m a n d graphite reflector.

These r e g i o n s may b e s e e n i n F i g . 4 . 2 0 , w h i c h shows the loading in a plane through t h e axis of the reactor.

T h e maximum cross section of the beryllium island w a s 9 by 9 i n . , a n d t h e m a x i m u m t h i c k n e s s o f t h e f u e l r e g i o n was 4 1/2 inches.

(With m a t e r i a l s a v a i l a b l e , i t was n o t p o s s i b l e t o c o m p l e t e l y f i l l the fuel region a t a l l axial locations.)

The t h i c k n e s s i n t h e f u e l r e g i o n was d e c r e a s e d i n b o t h d i r e c t i o n s from t h e c e n t e r t o s i m u l a t e t h e i n l e t and o u t l e t d u c t s o f t h e full-scale reactor.

Figure 4.21 i s a photograph of t h e assembly a t s e c t i o n AA o f F i g . 4 . 2 0 .

T h i s a s s e m b l y was c r i t i c a l w i t h a l o a d i n g o f 7 . 7 kg of u235

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 BetRET DWG. 18733

+

1.5

A

W

f 1.0 a

-1 W

r r

1

1

> k v)

z

1' E XPERl MENTAL (NOT NORMALIZED)

W

n (3

z

0

0.5

v,

E LL

0

6

'18

3/16

THICKNESS OF STAINLESS STEEL (in)

0

9

10

11

12

13

14

Fig. 4.19.

Reactivity L o s s vs.

Thickness of S t a i n l e s s S t e e l a t the F u e l - R e f 1 ec t o r I n t e r f a c e o f th'e F i r s t C r i t i c a l Assembly.

SPACE POINT, n (r=1,757n,cm)

F i g . 4 . 1 8 . Measured t r i b u t i o n i n t h e Fuel Region of the F i r s t C r i t i c a l Assembly.

Neutron f l u x d i s t r i b u t i o n w i t h b a r e - and c a d m i u m - c o v e r e d - i n d i u m f o i l s along a horizontal traverse l y i n g i n t h e mid-plane o f t h e assembly a r e shown i n F i g . 4 . 2 2 .

Note t h e s p a t i a l d i s t r i b u t i o n o f t h e cadmium h a t i s , t h e f r a c t i o n of t e d by i n d i u m , t h a t e l o w t h e cadmium e experimen t a 1 v a l u e s f r a c t i o n and t h o s e u l t i g r o u p method a r e The d i f f e r e n c e i s w i t h i n , except a t the f a c e where i t is periments indicate a n e u t r o n e n e r g y l o w e r t h a n t h a t computed for t h i s point.

(Recent d a t a i n d i c a t e t h a t t h i s d i f f e r e n c e may b e c a u s e d by

t h e void a t t h e i n t e r f a c e , which i s peculiar t o the s t r u c t u r e of t h e c r i t i c a l experiment. 1 T h e e x p e r i m e n t a l cadmium f r a c t i o n c u r v e shown i n F i g . 4 . 2 1 i s r e p e a t e d a s c u r v e A i n Fig. 4 . 2 3 , which g i v e s t h e d i s t r i b u t i o n of t h e f r a c t i o n of n e u t r o n s , d e t e c t e d by i n d i u m , w i t h e n e r g i e s b e l o w t h e cadmium c u t - o f f .

Curve B of F i g . 4 . 2 3 was o b t a i n e d from t h e f i r s t c r i t i c a l e x p e r i m e n t .

Comparison of t h e two c u r v e s shows the similarity of the spectra i n the c e n t e r o f t h e f u e l i n t h e two a s s e m b l i e s .

I t i s t o be remembered t h a t t h e f u e l l a y e r i n t h e f i r s t mockup wi3s o n l y 3 in. thick.

A p r e l i m i n a r y measurement of t h e neutron leakage spectrum gave values o f t h e cadmium f r a c t i o n f o r i n d i u m d e t e c t e d n e u t r o n s a t t h e o u t s i d e edge of t h e r e f l e c t o r , b o t h on t h e a x i s and a t t h e s i d e a t t h e mid-plane.

T h e r e s p e c t i v e v a l u e s were 0 . 4 a n d

57

ANP PROJECT QUARTERLY PROGRESS REPORT

seeul3 DWG (8735

AXIS

L

Fig.

0.9.

4.20.

A

Vertical Cross-Section o f the Second C r i t i c a l Assembly.

A measure of t h e f i s s i o n r a t e or power d i s t r i b u t i o n i n a d i r e c t i o n p a r a l l e l t o t h e r e a c t o r a x i s h a s been obtained from the improvisation i l l u s t r a t e d i n F i g . 4.24.

Uranium metal disks, 1.4 in. i n d i a m e t e r a n d 0. 002 i n . t h i c k , i n c o n t a c t w i t h aluminum d i s k s , 0.005 i n . t h i c k , were placed a d j a c e n t t o one of the f u e l c o n t a i n e r s ; and t h e a c t i v i t y on t h e 58

aluminum, c a u s e d by r e c o i l i n g f i s s i o n f r a g m e n t s , was c o u n t e d . The low v a l u e a t t h e 17-in. a b s c i s s a point probably r e s u l t e d from t h e s h i e l d i n g of e x t e r n a l l y r e f l e c t e d n e u t r o n s by t h e l a y e r o f f u e l t h a t was t h i c k e r t h e r e t h a n a t t h e 20-in. a b s c i s s a p o i n t .

I n a s i m i l a r m a n n e r , an a t t e m p t was made t o d e t e r m i n e t h e f i s s i o n r a t e pattern i n a direction perpendicular

,PERIOD ENDING MARCH 10, 1953 /

I

Fig.

4.21.

Photograph o f Second C r i t i c a l Assembly a t S e c t i o n AA o f F i g . 4 . 2 0 .

59

ANP PROJECT QUARTERLY PROGRESS REPORT

-

+emsf DWG 18736

BERYLLIUM ISLAND

I

--&-

BERYLLIUM REFLECTOR

-GRAPHITE

-C

TO 27 i

0

.

BARE INDIUM, EXPERIMENTAL

A CADMIUM-COVERED INDIUM, EXPERIMENTAL EXPERIMENTAL CADMIUM FRACTION

A

CALCULATED C4DMIUM FRACTION

N 1.o

z

0

5a

LL E

I 2 2 D

a

0

0.5

.

5

0

10

15 DISTANCE FROM REACTOR AXIS (in.)

0 20

25

k

Fig. 4.22. Radial Indium Activation and Cadmium Fr Critical Assembly.

the Second

DWG. i 8 7 3 7

z

Q

+ V a

(r

LL

5

s9

Fig. 4.23.

60

...

Comparison o f the Cadmium Fractions in the Two Critical Assemblies.

PERIOD ENDING MARCH 1 0

19 53 ?rcmclDWG 1873

BERYLLIUM REFLECTOR

'

0.002-in. URANIUM DISK AND ALUMINUM CATCHER FOIL

5

0

Fig. 4.24.

Assembly.

IO

15 20 DISTANCE FROM REACTOR INTERFACE (in.)

25

35

30

Measured Power D i s t r i b u t i o n P a r a l l e l to A x i s o f Second C r i t i c a l

t o the axis along a horizontal l i n e lying i n the mid-plane.

Uranium d i s k s and s m a l l (5/16 i n . i n d i a m e t e r ) aluminum c a t c h e r f o i l s were p l a c e d between t h e f u e l c o n t a i n e r s .

The r e s u l t s show a c e n t e r - t o - e d g e a c t i v i t y r a t i o o f 0.45, t h a t i s , a 55% d e p r e s s i o n i n t h e power a c r o s s a f u e l l a y e r 3.75 i n . wide. By d i r e c t m e a s u r e m e n t w i t h 2 0 - m i l cadmium i n t h e f i r s t c r i t i c a l a s s e m b l y , i t was f o u n d t h a t 7 0 % o f t h e f i s s i o n s w a s c a u s e d by n e u t r o n s w i t h e n e r g y b e l o w t h e cadmium cut-off.

From t h e s i m i l a r i t y o f t h e sDectra. it i s suspected t h a t about t h e same d i s t r i b u t i o n o c c u r s i n t h e o d i r e c t measurement

A. P. F r a a s , ANP D i v i s i o n

t h e design of t h e f u l l - s c a l e r e a c t o r shown i n F i g . 4 . 2 5 s h o u l d l o g i c a l l y p r e c e d e a d e t a i l e d d e s c r i p t i o n , an e x p o s i t i o n of t h e s e c o n s i d e r a t i o n s w i l l b e g r e a t l y s i m p l i f i e d by e a r l y reference t o a f a i r l y specific system.

Therefore, t h i s s e c t i o n begins with a d e s c r i p t i o n o f t h e r e f l e c t o r -molder a t e d r e a c t o r d e s i g n and s u b s e q u e n t l y t a k e s u p t h e m o r e s i g n i f i c a n t o f t h e many f a c t o r s t h a t have entered i n t o t h a t d e s i gn

.

Much w o r k r e m a i n s t o b e d o n e on r e f l e c t o r - m o d e r a t e d r e a c t o r s to g i v e better bases f o r d e t a i l e d designs, b u t t h e c o n s t r u c t i o n i n d i c a t e d by F i g . 4.25 seems t o be t h e most p r o m i s i n g o n e c o n s i d e r e d , t o d a t e , f o r an a i r c r a f t power p l a n t .

This cross section through t h e r e a c t o r core, m o d e r a t o r , and h e a t e x c h a n g e r shows a s e r i e s of f o u r c o n c e n t r i c s h e l l s , e a c h o f which i s a s u r f a c e o f r e v o l u t i o n .

I

A l t h o u g h t h e many c o m p l e x a n d i n t e r r e l a t e d considerations underlying

61

ANP PROJECT QUARTERLY PROGRESS REPORT

i

-

o

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 The two i n n e r s h e l l s s u r r o u n d t h e f u e l region a t the center, that is, t h e c o r e o f t h e r e a c t o r , and s e p a r a t e i t from t h e b e r y l l i u m i s l a n d a t t h e c e n t e r and f r o m t h e o u t e r b e r y l l i u m reflector.

The f u e l c i r c u l a t e s downward t h r o u g h t h i s r e g i o n i n w h i c h t h e f i s s i o n i n g t a k e s p l a c e and t h e n downward a n d o u t w a r d t o t h e e n t r a n c e of t h e s p h e r i c a l s h e l l h e a t exchanger t h a t l i e s between t h e m o d e r a t o r o u t e r s h e l l and t h e m a i n p r e s s u r e s h e l l .

The f u e l f l o w s upward b e t w e e n t h e t u b e s i n t h e h e a t e x c h a n g e r i n t o two m i x e d f l o w pumps a t t h e t o p .

From t h e pumps, i t i s d i s c h a r g e d i n w a r d t o t h e t o p of t h e a n n u l a r p a s s a g e l e a d i n g back t o t h e r e a c t o r c o r e .

The t o t a l f u e l volume i n t h e system f o r t h i s d e s i g n would b e a p p r o x i m a t e l y 7 f t 3 , o f which a p p r o x i m a t e l y 1 1 / 3 f t 3 would be i n t h e r e a c t o r core.

Most o f t h e r e m a i n i n g f u e l would b e i n t h e i n t e r s t i c e s between t h e t u b e s i n t h e heat exchanger.

The m o d e r a t o r was d e s i g n e d t o be c o o l e d by s o d i u m f l o w i n g downward t h r o u g h t h e a n n u l a r s p a c e b e t w e e n t h e b e r y l l i u m and t h e e n c l o s i n g s h e l l s and b a c k upward through passages i n the beryllium.

Two c e n t r i f u g a l p u m p s a t t h e t o p c i r c u l a t e t h e sodium f i r s t t h r o u g h t h e moderator and t h e n t h r o u g h t h e s m a l l t o r o i d a l sodium-to-NaK h e a t e x c h a n g e r s around t h e o u t e r p e r i p h e r y o f t h e pump and e x p a n s i o n t a n k r e g i o n .

A horizontal section through the pump a n d e x p a n s i o n t a n k r e g i o n i s shown i n F i g . 4 . 2 6 .

N o t e t h a t sump pumps w i t h g a s s e a l s a r e u s e d .

A pump o f t h i s t y p e r e c e n t l y c o m p l e t e d 1 0 0 0 h r of v e r y s u c c e s s f u l o p e r a t i o n i n a f l u o r i d e s y s t e m , w i t h pump i n l e t t e m p e r a t u r e s o f a b o u t 1400'F. The p r i m a r y c o n s t r u c t i o n m a t e r i a l i s I n c o n e l b e c a u s e i t seems t o b e t h e m a t e r i a l t h a t i s most r e s i s t a n t t o fluoride corrosion.

B e r y l l i u m was chosen a s the moderator m a t e r i a l , p a r t l y b e c a u s e i t seemed t o be t h e b e s t m a t e r i a l o b t a i n a b l e , from b o t h s h i e l d i n g and c r i t i c a l mass s t a n d p o i n t s , and p a r t l y b e c a u s e i t s p h y s i c a l

p r o p e r t i e s seem t o b e s u p e r i o r t o t h o s e of any o t h e r m a t e r i a l t h a t m i g h t be u s e d i n t h a t l o c a t i o n , o t h e r t h a n graphite.

I t was d e c i d e d t h a i t t h e vase-shaped i s l a n d i n t h e c e n t e r should be u s e d , p a r t l y because i t r e d u c e d t h e c r i t i c a l mass and i m p r o v e d t h e power d i s t r i b u t i o n i n t h e f u e l r e g i o n , and p a r t l y because hydrodynamically i t promised t o give t h e s i m p l e s t and most d e s i r a b l e f u e l passage.

The 1 2 - i n . - t h i c k b e r y l l i u m r e f l e c t o r f o l l o w e d by 1 i n . o f b o r o n c a r b i d e was c h o s e n o r i g i n a l l y t o keep t h e n e u t r o n s e s c a p i n g t o t h e heat exchanger region t o a level approximately equal t o t h a t of t h e d e l a y e d - n e u t r o n f l u x from t h e csircul a t i n g f u e l i n t h a t region.

It has s i n c e p r o v e d t o be n e a r l y a n optimum c o n f i g u r a t i o n f r o m b o t h c r i t i c a l mass and s h i e l d i n g s t a n d p o i n t s .

The s p h e r i c a l s h e l l h e a t e x c h a n g e r , which makes p o s s i b l e t h e c o m p a c t l a y o u t of t h e r e a c t o r - h e a t e x c h a n g e r a s s e m b l y , i s b a s e d on t h e u s e o f t u b e b u n d l e s c u r v e d i n s u c h a way t h a t t h e tube spacing i s uniform, i r r e s p e c t i v e o f l a t i t u d e . ( ) The i n d i v i d u a 1 t u b e bundles terminate i n headers t h a t resemble shower h e a d s b e f o r e t h e t u b e s a r e welded i n p l a c e .

This arrangement f a c i l i t a t e s assembly because a l a r g e number of s m a l l tube-to-header

assemblies

i s made

l e a k t i g h t much m o r e e a s i l y t h a n o n e large unit.

Furthermore, these tube bundles g i v e a rugged f l e x i b l e cons t r u c t i o n t h a t resembles steel cable and i s admirably a d a p t e d t o mervice i n which l a r g e amounts o f d i f f e r e n t i a l t h e r m a l e x p a n s i o n must be explected.

T h i s b a s i c t u b e b u n d l e and s p a c e r c o n s t r u c t i o n was u s e d i n a small NaK-to-NaKheat e x c h a n g e r t h a t o p e r a t e d s a t i s f a c t o r i l y f o r 3000 h r w i t h a NaK i n l e t t e m p e r a t u r e o f 1500'F. ( 6 , Two (5)A. P. F r a a s and M. E . L a v e r n e , H e a t E x c h a n g e r D e s i g n C h a r t s , OWL-1330, Dec. 7 , 1952. ( 6 ) G . H. Cohen, A. P. F r a a s , and EA. E. L a v e r n e , H e a t T r a n s f e r and P r e s s u r e L o s s i n T u b e B u n d l e s f o r H i g h P e r f o r m a n c e H e a t E x c h a n g e r s crnd F u e 1 E l e m e n t s , OWL-1215, Aug. 1 2 , 1 9 5 2 .

63

ANP PROJECT QUARTERLY PROGRESS REPORT 1 DWG f8739

i

No K

Fig. 4 . 2 6 .

Cross Section Through Pump and Expansion Tank.

s o d i u m pumps a n d two s o d i u m - t o - N a K h e a t exchangers a r e provided s o t h a t f a i l u r e o f o n e pump o r o n e h e a t exchanger w i l l n o t completely d i s a b l e the reactor.

F a c t o r s A f f e c t i n g Core Diameter.

The f i r s t f a c t o r c o n s i d e r e d i n e s tablishing the reactor core diameter ( t h e f u e l r e g i o n ) was t h e e f f e c t o f d i a m e t e r on c r i t i c a l m a s s .

Although much w o r k r e m a i n s t o b e d o n e t o establish the core diameter, it a p p e a r s , a t t h i s time, t h a t t h e c r i t i c a l mass i s e s s e n t i a l l y i n d e p e n d e n t of t h e c o r e d i a m e t e r . A more i m p o r t a n t f a c t o r a f f e c t i n g c r i t i c a l mass i s t h e

64

p r e s e n c e and s i z e o f t h e i s l a n d .

It appears t h a t the use of a beryllium i s l a n d with a diameter one-half t h a t of the fuel region cuts the c r i t i c a l mass a p p r o x i m a t e l y i n h a l f .

At the same t i m e , t h e i s l a n d r e d u c e s t h e r a t i o of t h e p e a k - t o - a v e r a g e power d e n s i t y by a f a c t o r o f a b o u t 1 . 5 .

F u r t h e r work on t h e e f f e c t s o f i s l a n d s i z e and f u e l region t h i c k n e s s i s u n d e r way.

A careful scrutiny of the data t h a t h a v e been o b t a i n e d on t h e m e l t i n g p o i n t , v i s c o s i t y , and t h e r m a l conduct i v i t y of v a r i o u s f l u o r i d e melts indicates t h a t i t w i l l probably n o t

r

PERIOD ENDING MARCH 10, 1953

C

.

be p o s s i b l e t o obtain a f l u o r i d e f u e l w i t h more t h a n 4 m o l e % u r a n i u m t h a t has c l o s e t o optimumphysical p r o p e r t i e s from t h e h e a t t r a n s f e r s t a n d p o i n t ; i n f a c t , from t h e standpoint of physical properties, there appears t o be an i m p o r t a n t i n c e n t i v e f o r k e e p i n g t h e uranium c o n c e n t r a t i o n l e s s t h a n 2 m o l e %.

On t h e b a s i s o f c r i t i c a l mass d a t a from t h e c a l c u l a t i o n s and t h e c r i t i c a l experiments, it appears t h a t a f u e l - r e g i o n diameter of a t l e a s t 18 i n . w i l l b e r e q u i r e d t o s a t i s f y t h i s condition.

A major c o n s i d e r a t i o n i n establishing the core diameter is the power d e n s i t y .

Work i s c u r r e n t l y u n d e r way t o d e t e r m i n e t h e e f f e c t o f p o w e r d e n s i t y on r a d i a t i o n d s m a g e .

A 1 though t h e e x p e r i m e n t a l r e s u l t s a r e d i f f i c u l t t o i n t e r p r e t and t h e r e f o r e no clearly defined l i m i t t o t h e a l l o w a b l e power d e n s i t y h a s been e s t a b l i s h e d , it is e n t i r e l y conceivable t h a t r a d i a t i o n damage c o n s i d e r a t i o n s w i l l n o t be t h e l i m i t i n g f a c t o r .

The k i n e t i c s of r e a c t o r c o n t r o l a r e v e r y complex.

Work c a r r i e d o u t t h u s f a r on c o n t r o l o f t h e r e a c t o r i n d i c a t e s t h a t t r a n s i e n t power s u r g e s may c a u s e u n a c c e p t a b l y l a r g e t e m p e r a t u r e excursions i f the temperature of t h e c i r c u l a t i n g f l u o r i d e f u e l exceeds 1 0 0 0 t o 2000'F p e r s e c o n d . A t e m p e r a t u r e r i s e of 2000째F/sec i n t h e f u e l would i m p l y a p o w e r d e n s i t y o f a p p r o x i m a t e l y 3 kw/cm3.

T h i s , i n t u r n , would mean t h a t a c o r e d i a m e t e r o f a b o u t 2 1 i n . would be r e q u i r e d f o r a 200,000kw r e a c t o r .

The p r o b l e m o f c o o l i n g t h e m o d e r a t o r becomes more s e v e r e a s power d e n s i t y i s increased.

A s t h e power d e n s i t y i s increased for a given r e a c t o r power o u t p u t , t h e p e r c e n t a g e o f t h e f i s s i o n energy t h a t appears a s h e a t i n t h e m o d e r a t o r i s i n c r e a s e d and t h e i n t e n s i t y of h e a t generation i n t h a t portion of t h e moderator c l o s e s t to t h e f u e l region is e s s e n t i a l l y 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 power d e n s i t y i n t h e f u e l . A l t h o u g h i t seems p r a c t i c a b l e

t o d e s i g n and b u i l d t h e modcerator cooling system f o r a r e a c t o r having power d e n s i t i e s o f up t o 8 o r 10 I t w / c m 3 , moderator cooling considerations seem t o i n d i c a t e t h a t p o w e r d e n s i t i e s h i g h e r t h a n 10 kw/cm3 w o u l d b e i n a d v i s a b 1 e.

Temperature v a r i a t i o n s i n t h e f l u i d f u e l i n t h e c o r e w i l l be a f u n c t i o n o f b o t h t h e v e l o c i t y d i s t r i b u t i o n and t h e power d e n s i t y .

With a g i v e n v e l o c i t y d i s t r i b u t i o n , i t would be expected t h a t c e r t a i n l o c a l i t i e s such a s t h e b o u n d a r y l a y e r or t h e c e n t e r s o f e d d i e s would r u n s u b s t a n t i a l l y h o t t e r t h a n t h e b u l k mean t e m p e r a t u r e of the fuel.

The m a g n i t u d e o f t h i s temperature d i f f e r e n t i a l w i l l depend, t o some e x t e n t , on t h e t h e r m a l c o n d u c t i v i t y of t h e f l u i d , but t h e r a t e a t w h i c h h e a t i s d i s p e r s e d by t u r b u l e n t interchange of p a r t i c l e s between h o t and c o l d r e g i o n s w i l l p r o b a b l y be much more i m p o r t a n t . T h e R e y n o l d ' s number f o r a h i g h - p o w e r r e a c t o r will\be somewhere b e t w e e n l o 5 and l o 6 , d e p e n d i n g on f u e l v i s c o s i t y and d e s i g n values for the reactor core diameter and t h e f u e l t e m p e r a t u r e r i s e .

At p r e s e n t , i t i s n o t p o s s i b l e t o make more t h a n t h e r o u g h e s t s o r t o f e s t i m a t e o f t h e magnitude of t h e temperature d i f f e r e n t i a l between t h e s e h o t s p o t s and t h e f r e e stream.

The problem i s being attacked both theoretically and e x p e r i m e n t a l l y , and i t i s hoped t h a t r e s u l t s from a t l e a s t t h e l a t t e r w i l l p l a c e an u p p e r l i m i t on t h e m a g n i t u d e o f t h e e f f e c t s t o be e x p e c t e d .

One p o s s i b l e i l l e f f e c t w i t h r e s p e c t t o c o n t r o l c o u l d a r i s e from t h e s e hot spots.

I f b o i l i n g were t o t a k e place, irregular fluctqations i n power l e v e l t h a t would p r o b a b l y be similar t o those experienced i n b o i l i n g e x p e r i m e n t s made w i t h t h e LITR(') would be e x p e c t e d t o r e s u l t .

There i s a l s o a p o s s i b i l i t y t h a t ( 7 ) W . M. B r e a z e a l e , T. E. C o l e , and J. A. Cox, J o u r n a l o f R e a c t o r S c i e n c e and T e c h n o l o g y , Vol. 11, NO. 2, TID-2002 11952); Vol. 11, NO. 4, TID-2004

(1952).

65

ANP PROJECT QUARTERLY PROGRESS REPORT c o u p l i n g o f t h e o s c i l l a t i o n s i n power with the periodic f l u c t u a t i o n s i n f l u i d flow t h a t caused t h e e d d i e s o r o t h e r h o t s p o t s might t a k e place.

After the various considerations o u t l i n e d a b o v e were e x a m i n e d , i t appeared t h a t only i n a f u l l - s c a l e e x p e r i m e n t c a n t h e maximum, a l l o w a b l e , power d e n s i t y i n a f l u i d - f u e l r e a c t o r c o r e be d e f i n i t e l y e s t a b l i s h e d . This, i n turn, implies that the f i r s t experiment of t h i s s o r t should be run with t h e smallest p r a c t i c a l core s i z e because the cost of t h e experiment would be l a r g e l y a f u n c t i o n of t h e t o t a l amount o f h e a t t o be d i s s i p a t e d .

Hence, t h e c h e a p e s t experiment t o y i e l d a d e f i n i t i v e answer w i l l b e t h e one c a r r i e d o u t with t h e s m a l l e s t r e a c t o r c o r e t h a t m i g h t r e a s o n a b l y be e x p e c t e d t o y i e l d a power p l a n t of adequate size.

Since f u e l chemistry and c r i t i c a l mass 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 an 1 8 - i n . - d i a c o r e i s t h e s m a l l e s t t h a t can be u s e d w i t h f l u o r i d e f u e l s t h a t have d e s i r a b l e p h y s i c a l p r o p e r t i e s , m o s t d e s i g n work h a s b e e n b a s e d on r e a c t o r c o r e s i z e s r a n g i n g from 18 t o 2 1 i n . i n d i a m e t e r .

T e m p e r a t u r e , P r e s s u r e , and S t r e s s .

Two m a j o r t e n e t s o f t h e d e s i g n p h i losophy have been t h a t t h e p r e s s u r e s throughout t h e f l u i d systems should be k e p t low, p a r t i c u l a r l y i n t h e h o t TABLE 4 . 2 .

z o n e s , and t h a t a l l s t r u c t u r e s h o u l d be cooled t o a t e m p e r a t u r e a p p r o x i m a t e l y e q u a l t o o r below t h a t o f t h e secondary coolant leaving t h e heat e x c h a n g e r . The t e m p e r a t u r e , p r e s s u r e , and stress values c a l c u l a t e d f o r various stations i n the reactor are i n d i c a t e d i n Fig. 4.27.

The s t r e s s e s i n the s t r u c t u r a l p a r t s have been k e p t t o a minimum.

Thermal stresses were n o t i n c l u d e d i n t h i s diagram, since i t is f e l t t h a t they w i l l anneal out a t t h e s e temperatures and, a t worst, w i l l cause a l i t t l e d i s t o r t i o n t h a t s h o u l d n o t be s e r i o u s .

Table 4.2 g i v e s s t r e n g t h d a t a on I n c o n e l and columbium.

Recent tests indicate t h a t i n t h e absence of oxygen t h e c r e e p r a t e o f I n c o n e l may b e t w o o r three t i m e s the rate given i n the t a b l e f o r a given stress level.

E x a m i n a t i o n o f F i g . 4 . 2 7 w i l l show t h a t t h e s t r e s s e s have been k e p t so low t h a t t h e c r e e p r a t e s h o u l d n o t prove t o be a s e r i o u s problem.

Note t h a t t h e highest stresses a r e i n t h e h e a t exchanger tubes.

A s m a l l , e x p e r i m e n t a l , h e a t exchanger h a s been designed f o r i n v e s t i g a t i n g t h e problem of f a b r i c a t i n g t u b e b u n d l e s and h e a d e r c o n n e c t i o n s o f the type required.

Although small, t h e h e a t exchanger s h o u l d be c a p a b l e o f t r a n s m i t t i n g 1.5 megawatts o f h e a t

i

L

:

r

STRENGTH OF INCONEL AND COLUMBIUM AT ELEVATED TEMPERATURES STRENGTH OF COLUMBIUM (psi)

A T 1200'F

A T 1400'F

A T 1600'F

A T 1800'F

U1t ima te tens i le s t r e n g t h

65,000

27,500

15,000

7,500

Yield s t r e n g t h (0.2% o f f s e t )

26,500

17,000

9,000

4,000

Stress-rupture a t 100 hr

21,000

8,500

4,500

2,800

Stress-rupture a t 1,000 h r

12,000

5,500

2,700

1,700

1%creep i n 10,000 h r

9,300

3,500

2,000

560

0.1% creep i n 10,000 h r Endurance l i m i t (10 a cycles)

5,500

1,700

1,700

340

26,500

15,500

10,000

7,000

66

I A T 1600'F

25,000

6,000+

A T 1800째F

20,000

P

PERIOD ENDING MARCH 10, 1953 +l?me DWG 483094

FUEL TO HEAT EXCHANGER TEMP = 1590'F PRESS :40 psi

the Reflector-

A N P PROJECT QUARTERLY PROGRESS REPORT

4

ii

f r o m t h e f l u o r i d e t o NaK. It i s expected t h a t , u l t i m a t e l y , s i x , small, heat exchangers w i l l be b u i l t f o r i n v e s t i g a t i n g t h e e f f e c t s on e n d u r a n c e l i f e of o p e r a t i o n a t v a r i o u s temperat u r e and p r e s s u r e l e v e l s .

F i g u r e 4.28 shows one t u b e b u n d l e f o r t h i s h e a t exchanger.

Six of these bundles w i l l be used i n a 5 - i n . - d i a c y l i n d r i c a l a n n u l u s i n s t e a d o f i n t h e l a r g e r and more c o m p l e x s p h e r i c a l s h e l l a r r a y e n v i s a g e d for t h e f u l l - s c a l e r e a c t o r .

The d e s i g n t e m p e r a t u r e l e v e l i n t h e sodium c i r c u i t f o r c o o l i n g t h e moderator region i s q u i t e t e n t a t i v e . ncELBLfEsb

4

1

Y-E893

i

1!

Mfwwc+cb Y-8858

i1!

(6)

F i g . 4 . 2 8 . Tube BundleforSpherical Reactor Heat Exchanger. la) One e n d of a completed t u b e bundle a n d " s h o w e r head" assembly. ( b ) Tube-to-header welded c o n n e c t i o n s .

68

The t e m p e r a t u r e s s p e c i f i e d i n F i g . 4 . 2 7 were b a s e d on t h e h i g h e s t t e m p e r a t u r e s t h a t a p p e a r r e a s o n a b l e from t h e s t a n d p o i n t o f c o m p a t i b i l i t y of t h e b e r y l l i u m sodium-Inconel system. Higher temperat u r e s would b e l i k e l y t o g i v e t r o u b l e b e c a u s e o f mass t r a n s f e r and b e c a u s e of a t t a c k of the Inconel canning m a t e r i a l by t h e b e r y l l i u m .

The temperature l e v e l s required should n o t be d i f f i c u l t t o a t t a i n , s i n c e t h e m o d e r a t o r h e a t would b e removed a t a high temperature level.

Two e n g i n e s could be f i t t e d with small a u x i l i a r y r a d i a t o r s p l a c e d between t h e compressor and t h e m a i n r a d i a t o r s .

These could be employed t o s u b c o o l a p o r t i o n o f t h e s e c o n d a r y c i r c u i t NaK t o , p e r h a p s , 900째F. T h i s c o o l e r NaK c o u l d t h e n b e f e d t o t h e Na-to-NaK h e a t e x c h a n g e r a t t h e top of t h e reactor.

T h e r e , by c o o l i n g t h e s o d i u m from t h e m o d e r a t o r c o o l i n g c i r c u i t , i t would be h e a t e d t o a b o u t 1 1 0 0 째 F s o t h a t i t would t h e n f l o w t o t h e main h e a t e x c h a n g e r a t t h e same t e m p e r a t u r e a s t h a t o f t h e NaK from t h e o t h e r r a d i a t o r c i r c u i t s .

Thus t h e weight p e n a l t y a t t a c h e d t o c o o l i n g t h e m o d e r a t o r r e g i o n would b e o n l y a b o u t 400 l b of r a d i a t o r c o r e p l u s p o s s i b l y 200 l b o f e x t r a r e a c t o r s h i e l d a n d 1 0 0 l b o f pump a n d l i n e weight.

Lead, b i s m u t h , a n o n u r a n i u m b e a r i n g f l u o r i d e , s o d i u m , a n d NaK w e r e a l l g i v e n s e r i o u s c o n s i d e r a t i o n a s cool a n t s f o r the beryllium moderator.

The m e t a l l u r g i s t s f e l t t h a t l e a d or b i s m u t h would b e l i k e l y t o p o s e a s e r i o u s mass t r a n s f e r problem.

The relatively high neutron absorption c r o s s s e c t i o n of t h e p o t a s s i u m i n t h e NaK made i t q u i t e u n d e s i r a b l e f r o m t h e c r i t i c a l mass s t a n d p o i n t . Rubidium might be used i n p l a c e o f p o t a s s i u m b u t , b e c a u s e of l i t t l e demand, i t i s c u r r e n t l y very expensive.

T h u s sodium seemed t o b e t h e b e s t c h o i c e f o r a moderator coolant.

Since corrosion and mass t r a n s f e r a r e l i k e l y t o o c c u r i n a Be-NaK-Na s y s t e m , i t s e e m e d e s s e n t i a l t h a t t h e b e r y l l i u m b e c l ad

, P E R I O D ENDING MARCH 1 0 , 1 9 5 3 i n some f a s h i o n .

Work a t B a t t e l l e ( * ) i n d i c a t e s t h a t b e r y l l i u m can be chrome-plated t o give 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 o d i u m a t t a c k a t 932'F. However, t h i s work w a s c a r r i e d o u t o n s m a l l specimens, and t h e r e i s a question a s t o whether adequate p r o t e c t i o n t o t h e very l a r g e s u r f a c e a r e a s r e q u i r e d would b e p r a c t i c a l .

An a l t e r n a t e p o s s i b i l i t y w o u l d b e t o can t h e beryllium i n thin-walled I n c o n e l c a n s and t o f i l l t h e s m a l l i n t e r s t i c e s between t h e b e r y l l i u m and t h e c a n w i t h s t a g n a n t sodium.

This a r r a n g e m e n t a p p e a r s t o be t h e more p r o m i s i n g o f t h e two, b u t b o t h p o s s i b i l i t i e s are being investigated, T h e r e f l e c t o r c o u l d b e c o n s t r u c t e d o f two l a r g e hemispheres of beryllium i f t h e c a n n i n g t e c h n i q u e were u s e d .

Cooling p a s s a g e s c o u l d be r i f l e - d r i l l e d t h r o u g h t h e b e r y l l i u m and l i n e d with t h i n w a l l e d t u b e s , which c o u l d b e welded i n t o headers a t t h e ends.

The Brush B e r y l l i u m Co. h a s i n d i c a t e d t h a t t h e f a b r i c a t i o n o f t h e s e 1a r g e h e m i s p h e r i c a l s h e l l s w o u l d p r o b a b l y be n o m o r e d i f f i c u l t than the fabrication of large f l a t slabs.

The p e r s o n n e l o f t h e Y-12 b e r y l l i u m shop s t a t e t h a t i t would n o t be d i f f i c u l t t o r i f l e d r i l l h o l e s 3 / 1 6 t o 1/4 i n . i n d i a m e t e r a n d a s much a s 40 i n . d e e p , w i t h t h e hole diameter h e l d t o within 0.001 in. and t h e h o l e c e n t e r l o c a t i o n h e l d t o w i t h i n 0.010 i n c h .

S i n c e i t would b e very d i f f i c u l t t o p l a t e t h e i n s i d e s of h o l e s , an a l t e r n a t e c o n s t r u c t i o n t h a t appears a t t r a c t i v e , i f chrome-plated blocks prove p r a c t i c a b l e , i s t h e use o f a l a r g e number o f wedge-shaped s e g m e n t s , w h i c h would b e s h a p e d much l i k e t h e s e c t i o n s o f an o r a n g e . These could with shallow grooves i n t h e i t would form p a s s a g e s f o r c o o l i n g s t r e a m s o f sodium i n t h e a s s e m b l y .

The c h o i c e o f a s e c o n d a r y c o o l a n t was d i f f i c u l t . C a r e f u l e x a m i n a t i o n of t h e components i n t h e e x t e r n a l s y s t e m

-

(*)J. G . B e a c h a n d C. L. F a u s t , E l e c t r o p l a t i n g o n B e r y l l i u m , BMI-732 ( A p r . 1. 1 9 5 2 ) .

i n d i c a t e s t h a t a b o u t 40 f t 3 o f f l u i d would be r e q u i r e d a s a minimum,, T h i s m e a n s t h a t i f l e a d o r b i s m u t h were u s e d , t h e w e i g h t r e q u i r e d w o u l d be i n t h e range o f 30,000 pounds.

A number o f molten s a l t m i x t u r e s w a s considered, but the melting points i n a l l cases were above 300"F, which i s o b j e c t i o n a b l y high.

O t h e r m e d i a were r e j e c t e d b e c a u s e of c o r r o s i o n c o n s i d e r a t i o n s .

Sodium o r NaK seemed t o be d e f i n i t e l y s u p e r i o r t o any o t h e r c o o l a n t considered except for the objectionable n e u t r o n a c t i v a t i o n and r e s u l t a n t gamma a c t i v i t y o f sodium, and t h e f i r e hazard associated with a possible leak.

Shielding characteristics i n d i c a t e t h a t f o r t h e m o s t p r o ~ m i si n g distribution of shielding material between t h e r e a c t o r and t h e c r e w , gamma a c t i v i t y from t h e sodium would be l e s s t r o u b l e s o m e t h a n t h e p r o m p t -gamma a c t i v i t y from t h e r e a c t o r c o r e .

Cons i d e r a b l e e x p e r i e n c e w i t h sodium h a s indicated t h a t i f the plumbing i s designed t o keep t h e s t r e s s e s l o w s o t h a t burst types of f a i l u r e w i l l n o t r e s u l t , l e a k s t h a t do o c c u r a s t h e r e s u l t of fatigue cracks o r corrosion p i t s develop s l o w l y and do n o t r e s u l t in serious fires.

In fact, since sodium d o e s n o t e x p l o d e ( s o l o n g a s n o w a t e r i s p r e s e n t ) , i n many w a y s i t seems n o more h a z a r d o u s t h a n g a s o l i n e .

A f t e r a l l t h e f a c t o r s were w e i g h e d , t h e most p r o m i s i n g s e c o n d a r y f l u i d a p p e a r e d t o be NaK. A 56% s o d i u m a n d 44% p o t a s s i u m a l l o y , w h i c h h a s a m e l t i n g p o i n t o f 56"F, was c h o s e n f o r t h e analysis.

Its l o w melting point, excellent heat transfer characteristics, good c o r r o s i o n c h a r a c t e r i s t i c s i n iron-chrome-nickel a l l o y s , and l o w d e n s i t y made i t a p p e a r t o b e t h e b e s t choice.

Reflector Heating (A. H. Fox, R. W. B u s s a r d , ANP D i v i s i o n ) .

The h e a t i n g o f t h e r e f l e c t o r o f a r e a c t o r by t h e a b s o r p t i o n o f gamma r a d i a t i o n and t h e s l o w i n g down o f n e u t r o n s o r i g i n a t i n g i n t h e core p r e s e n t s a h e a t removal t a s k t h a t is o n l y a n o r d e r o f m a g n i t u d e

69

ANP PROJECT QUARTERLY PROGRESS REPORT smaller than t h a t of cooling t h e core itself.

The d i s t r i b u t i o n o f t h e h e a t g e n e r a t e d i n t h e m o d e r a t o r d e p e n d s on t h e s t r e n g t h and l o c a t i o n of t h e s o u r c e s and o n t h e a t t e n u a t i o n o f t h e r a d i a t i o n between t h e s o u r c e s a n d t h e p o i n t i n q u e s t i o n . F o r t h e gamma-ray e n e r g i e s o f i n t e r e s t , t h e mechanism o f degradation involves principally the Compton c o l l i s i o n s .

T h e mechanism o f degradation of energy of the core gammas i s c o m p l i c a t e d , e v e n w i t h t h e most s i m p l e geometry o f s o u r c e and r e f l e c t o r ; f o r a m o r e complex g e o m e t r y , such a s t h a t of the reflector-moderated r e a c t o r , many s i m p l i f y i n g a s s u m p t i o n s a r e n e c e s s a r y b e f o r e e v e n an a p p r o x i mate e s t i m a t e o f t h e r a t e o f h e a t g e n e r a t i o n i n t h e b e r y l l i u m may b e obtained.

The f i r s t a p p r o x i m a t i o n u s e d i n volved the straight-ahead theory of gamma a b s o r p t i o n f o r which i t is assumed t h a t Compton c o l l i s i o n s m e r e l y d e g r a d e i n e n e r g y and do n o t s c a t t e r t h e p h o t o n s . Only e x p o n e n t i a l a t t e n u a t i o n with a coefficient that i s charact e r i s t i c o f t h e m a t e r i a l t h r o u g h which t h e p h o t o n s p a s s n e e d be c o n s i d e r e d .

When a p h o t o n p a s s e s f r o m o n e medium t o a n o t h e r , no r e f r a c t i o n i s considered.

Use o f a b u i l d u p f a c t o r t o allow for ordinary s c a t t e r i n g i s being i n ves t i ga t e d Another simplifying assumption concerned the source d i s t r i b u t i o n .

O n l y t h e t o t a l a m o u n t o f gamma f l u x was c o n s i d e r e d , and v a r i a t i o n s from p o i n t t o p o i n t i n t h e c o r e were neglected, Thus an a v e r a g e power d e n s i t y f o r t h e c o r e was d e t e r m i n e d s i m p l y by d i v i d i n g t h e t o t a l r e a c t o r power o u t p u t by t h e volume o f t h e f u e l region of t h e core.

(An i n v e s t i g a t i o n o f s o u r c e s d i s t r i b u t e d a s i n d i c a t e d by t h e c r i t i c a l e x p e r i m e n t s showed o n l y a small v a r i a t i o n i n r e s u l t s . ) The p a r t i c u l a r c a s e c o n s i d e r e d was t h a t o f an 1 8 - i n . - d i a , s p h e r i c a l , fluoride-fuel region surrounding a 9-in.-dia, c e n t r a l , beryllium island

.

70

and e n c l o s e d by a 1 2 - i n . - t h i c k b e r y l l i u m r e f l e c t o r , A 3/16-in.-thick layer of I n c o n e l was c o n s i d e r e d a s b e i n g t h e s e p a r a t i n g m a t e r i a l between t h e f u e l r e g i o n a n d e a c h o f t h e two m o d e r a t o r r e g i o n s . The f e a c t o r power o u t p u t was t a k e n a s 200 m e g a w a t t s , and t h e e n e r g y e v o l v e d i n t h e gammas was t a k e n a s 12 M e v / f i s s i o n , which gave a t o t a l power f r o m gammas o f 1 2 m e g a w a t t s and a gamma s o u r c e d e n s i t y i n t h e f u e l r e g i o n o f 275 w a t t s / c m 3 .

The a v e r a g e gamma e n e r g y was assumed t o be 1 M e V , and t h e r e c i p r o c a l a t t e n u a t i o n l e n g t h s f o r t h e f u e l , I n c o n e l , and b e r y l l i u m m o d e r a t o r r e g i o n s were t a k e n a s 0 . 0 9 , 0.3'0, and 0 . 1 6 cm", respectively.

The power d e n s i t y was c o m p u t e d a t p o i n t s spaced about 1 i n . a p a r t along a r a d i u s from t h e c e n t e r o f t h e i s l a n d t o the outside of the r e f l e c t o r .

The r e s u l t i n g values a r e given i n Table 4 . 3 ( c a s e A ) and F i g . 4.29.

T a b l e 4.4 ( c a s e A) shows t h e i n t e g r a t e d v a l u e s of t h e power, i n t h e v a r i o u s r e g i o n s o f i n t e r e s t , o b t a i n e d by g r a p h i c a l i n t e g r a t i o n o f t h e power d e n s i t y c u r v e .

The f a c t t h a t t h e t o t a l gamma h e a t i n g i n d i c a t e d by T a b l e 4 . 3 i s o n l y 1 0 . 6 megawatts i n s t e a d o f t h e 12 megawatts assumed i s d u e , i n p a r t , t o l e a k a g e from t h e r e f l e c t o r a n d , i n p a r t , t o t h e a p p r o x i m a t i o n s made f o r t h e c o m p u t a t i o n s . However, i t i s b e l i e v e d t h a t t h e d i s t r i b u t i o n o f t h e gamma h e a t i n g i s a p p r o x i m a t e d q u i t e w e l l by F i g . 4.29.

One i m p o r t a n t r e s u l t o f t h i s work i s t h a t f o r t h i s c o n f i g u r a t i o n more t h a n 60% o f t h e gamma e n e r g y g o e s into heating the fuel.

A second c o m p u t a t i o n was made w i t h d i f f e r e n t values for the reciprocal attenuation l e n g t h s , t h a t i s , 0 . 0 6 an'd 0 . 1 3 c m - ' f o r t h e f u e l and b e r y l l i u m , res p e c t i v e l y , and t h e r e s u l t s a r e shown i n T a b l e 4 . 3 a s c a s e B. A s can be s e e n , t h i s r e l a t i v e l y l a r g e c h a n g e had n o g r e a t e f f e c t on t h e d i s t r i b u t i o n o f t h e gamma h e a t i n g .

The t o t a l power f o r b o t h c a s e A and c a s e B i s g i v e n i n T a b l e 4.4.

. _

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 M OWG 48740

450

400

350

-

m

300

5

\ fn

+

250 d .

t

rln z

200

a

W

: P

I50

too

50

0

0

2

6

4

8

io

12

F i g . 4.29.

16

i4

RADIAL DISTANCE FROM REACTOR CENTER LINE,

f

18

20

(in.)

Radial Power Density from Neutron and Gamma Heating. i s n o r m a l i z e d t o t h e t o t a l power l o s t by m o d e r a t i o n ( 2 1 / 2 % o f r e a c t o r p o w e r ) by t h e u s e o f t h e i n t e g r a t i o n o p e r a t o r *

F.

(correction gy l o s s f o r e a c h

c o l l i s i o n s i n t h a t group a t a given r a d i u s or s p a c e p o i n t , The s p a t i a l distribution,

The power d e n s i t i e s r e s u l t i n g f r o m n e u t r o n m o d e r a t i o n a n d f r o m gamma h e a t i n g , a s o b t a i n e d by t h e m e t h o d s described above, a s w e l l a s the r e s u l t a n t t o t a l power d e n s i t y , a r e shown i n F i g . 4 . 2 9 , Severe peaks i n t h e Inconel s h e l l s and a r a p i d d r o p w i t h d i s t a n c e from t h e f u e l r e g i o n a r e shown.

A n u m b e r o f f a c t o r s m u s t lbe c o n sidered i n the design of a system of

71

ANP PROJECT QUARTERLY PROGRESS REPORT TABLE 4 . 3 .

POWER D E N S I T Y I N V A R I O U S R E G I O N S R A D I A L D I S T A N C E FROM CENTER OF REACTOR CORE

REGION

r (in.)

Island beryllium

0

(cm)

Case A

Case B

2 3 4 4.31

0 5.08 7.62 10.16 10.95

47.5 60 80 101 120

61.9 65 74 93 142

I s l a n d Inconel

4.31 4.5

10.95 11.4

223 3 54

330 497

Fue 1

4.5 5 5.5 6. 0 6.75 8.5 9

11.4 12.7 14 15.2 17.1 20.3 21.6 22.9

106 167 186 182 184 157 141 73

99 137 148 152 151 132 116 65

9 9.19

22.9 23.3

215 150

325 227

9.19 9.5 10 10.5 11 12 13 14 15 21

23.3 24.1 25.4 26.7 27.9 30.5 33.0 35.6 38.1 53.3

8

Reflector Inconel

Re f 1e c t o r be r y 11i urn

REGION

Island beryllium Island Inconel Fue 1 Reflector Inconel Reflector beryllium

72

r

RATE OF HEAT G E N E R A T I O N FROM GAMMAS 3 (watts/cm )

TOTAL POWER (megawatts) Case A

Case B

0.46 0.24 6.71 0.57 3.14

0. 51 0.29 5.58 0.85 3.44

80 53.7 37.7 25.4 19.0 10.3 5.4 2.9 1.67 0.066

98 57 44.6 31.9 2.4.4 14.0 8.3 4.9 3.0 0.19

m o d e r a t o r c o o l i n g p a s s a g e s . The volume o f b o t h t h e sodium a n d , e s p e c i a l l y , t h e I n c o n e l m u s t be m i n i m i z e d t o k e e p p a r a s i t i c neutron absorptions within reasonable l i m i t s .

The n e u t r o n f l u x c u r v e s show t h a t from t h e n e u t r o n economy s t a n d p o i n t c o o l a n t p a s s a g e s i n t h e b e r y l l i u m a r e much more i m p o r t a n t s e v e r a l i n c h e s from t h e f u e l r e g i o n than a t t h e fuel-moderator i n t e r f a c e .

T h e r m a l s t r e s s e s w i l l b e s e t u p by temperature variations i n the beryllium.

S i n c e an e l o n g a t i o n o f a b o u t

...

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 30% c a n be o b t a i n e d i n b e r y l l i u m a t t h e operating temperatures envisioned, thermal stresses should n o t lead t o cracking but might cause d i s t o r t i o n t h a t c o u l d become a p r o b l e m a f t e r a number o f t h e r m a l c y c l e s o f t h e s y s t e m , For t h i s reason, t h e temperature v a r i a t i o n i n t h e b e r y l l i u m between a d j a c e n t c o o l a n t p a s s a g e s was h e l d t o SOOF. T h e p r e s s u r e d r o p t h r o u g h t h e various coolant passages w a s limited t o 40 p s i t o k e e p p r e s s u r e - i n d u c e d s t r e s s e s low.

The maximum b e r y l l i u m s o d i u m i n t e r f a c e t e m p e r a t u r e was h e l d

b e l o w 1 2 0 0 째 F t o r e d u c e mass t r a n s f e r i n t h e B e - s t a g n a n t - N a - I n c o n e l s y s tern, S e v e r a l d e t a i l d e s i g n s were i n v e s t i g a t e d t h a t favored f i r s t one and t h e n a n o t h e r of t h e v a r i o u s r e q u i r e m e n t s , t h a t i s , minimum p o i s o n , minimum variation i n beryllium temperature, m i n i mu m b e r y 11i u m s o d i ~1m i n t e r f a c e t e m p e r a t u r e , minimum s o d i u m s y s tem pressure drop, e t c .

F i g u r e 4.30 shows the hole pattern i n the beryllium for a p r o m i s i n g a r r a n g e m e n t , and t h e r e s u l t i n g temperature d i s t r i b u t i o n is s h o w n i n F i g . 4.31.

-

Sf!t%Pl

DWG 48744

PASSAGE FOR INLET No TO REFLECTOR (2 REQ'D)

0.26-in. - DIA HOLES IN Be, CONTAINING 0.25-in. -OD TUBES FOR No COOLANT FLOW

REFLECTOR-MODERATOR

-__Et__-

Fig. 4.30.

Cooling Hole D i s t r i b u t i o n i n Reflector-Moderator.

73

ANP PROJECT QUARTERLY PROGRESS REPORT

1600

1400

1200

-

1000

lL

e

W

a 2

800 W

Q

z W c

600

400

200

0 0

2

4

6 8 10 12 14 RADIAL DISTANCE FROM REACTOR CENTER L I N E (in.)

16

18

20

F i g . 4.31.

Temperature D i s t r i b u t i o n A c r o s s Midplane o f 200-Megawatt Reflector-Moderated Reactor.

Sodium i n l e t , 100O0F.

SHIELDING

A. P. F r a a s , ANP D i v i s i o n J. B. T r i c e , S o l i d S t a t e D i v i s i o n The s h i e l d d e s i g n p h i l o s o p h y t h a t h a s b e e n the_ b a s i s o f t h e w o r k o n th. reflector-moderated r e a c t o r s h i e l d h a s been t h a t a n o p e r a t i o n a l a i r p l a n e , i n t h e m i l i t a r y s e n s e of t h e word, c a n h a r d l y be a c h i e v e d w i t h a s h i e l d d i vided t o such a degree t h a t an unp r o t e c t e d man 5 0 f t f r o m t h e r e a c t o r r e c e i v e s a l e t h a l dose i n 15 s e c ( a s envisioned for the a i r cycle).

Those e x p e r i e n c e d i n a i r c r a f t o p e r a t i o n and m a i n t e n a n c e know t h a t p e r h a p s 50% o f t h e m a i n t e n a n c e work i n v o l v e s non-

74

scheduled operations, the character and d e t a i l e d n a t u r e of w h i c h a r e i t n p o s s i b 1e t 0,' p r e d i c t w i t h o u t a n e x t e n s i v e background of e x p e r i e n c e .

P r o v i s i o n of an a d e q u a t e s e t of e q u i p m e n t a n d f a c i l i t i e s t o t a k e c a r e 0' a l l contingencies promises t o involve e x p e n d i t u r e s of t h e same o r d e r a s t h o s e r e q u i r e d f o r t h e n u c l e a r power plant itself, I t was f e l t t h a t i f t h e r a d i a t i o n d o s e a t f u l l power c o u l d be c u t t o a b o u t 1 0 r / h r a t 5 0 f t from t h e r e a c t o r , t h e g r e a t e r m a j o r i t y of the nonscheduled maintenance j o b s t h a t might d e l a y a f l i g h t a t t h e l a s t minute o r r e q u i r e emergency a t t e n t i o n immediately following a landing could

PERIOD ENDING MARCH 10, 1953 be h a n d l e d w i t h o u t s p e c i a l e q u i p m e n t .

For t h i s r e a s o n , e f f o r t h a s b e e n d i r e c t e d t o w a r d t h e d e v e l o p m e n t of something c l o s e l y approaching a u n i t It is f u l l y r e a l i z e d t h a t a shield, weight p e n a l t y is i n e v i t a b l e .

It was f o u n d t h a t t h e i n i t i a l s t a r t u p and warmup o f t h e r e a c t o r c a n p r o b a b l y b e c a r r i e d o u t a t power l e v e l s t h a t , i n g e n e r a l , do n o t exceed 1 0 % o f t h e f u l l power of t h e r e a c t o r ; thus the r a d i a t i o n dose d u r i n g s t a r t u p a n d warmup w o u l d be 1 0 % o f t h a t a t f u l l power.

I f i n the tuneup process t h e o p e r a t i o n s must be c a r r i e d o u t close t o the reactor, the reactor m i g h t b e i d l e d down f r o m 10% t o p e r h a p s 1% o f f u l l p o w e r o u t p u t s o t h a t t h e r a d i a t i o n ' d o s e a t any p a r t i c u l a r p o i n t w o u l d b e o n l y 1% o f t h e full-power dose.

I t is t r u e , however, t h a t a f t e r a l o n g f l i g h t t h e accumul a t i o n of f i s s i o n products w i l l c o n s t i t u t e a s u b s t a n t i a l gamma d o s e e v e n a f t e r t h e r e a c t o r i s s h u t down completely.

T h i s d o s e w i l l s t i l l be o n l y o f t h e o r d e r o f 1 o r 2% o f t h e t o t a l r a d i a t i o n d o s e a t f u l l power o u t p u t b e c a u s e t h e d e c a y gammas a r e f e w e r i n number and s o f t e r t h a n t h e prompt gammas.

A d r a i n v a l v e w i l l be p r o v i d e d a t t h e bottom of t h e r e a c t o r s o t h a t the fluoride fuel canbe drained i n t o underground tanks.

I t is hoped t h a t a b o u t 98% o f t h e f u e l c a n be removed by a s i m p l e d r a i n i n g o p e r a t i o n and t h a t most of t h e r e m a i n i n g f u e l c a n b e f l u s h e d o u t by u s i n g a n o n aring fluoride.

Precisely what c a n be d e in this direction is difficult p r e d i c t , b u t one of t h e major items of i n f o r m a t i o n e x p e c t e d f r o m ARE t e s t work i s t h e e x t e n t t o which t h e r a d i a t i o n from a c i r c u l a t i n g - f l u o r i d e - f u e 1 r e a c t o r can b e r e d u c e d by d r a i n i n g a n d f l u s h i n g .

The d e g r e e t o which t h e I n c o n e l s t r u c t u r e w i l l be a c t i v a t e d a n d w i l l represent an important source of r a d i a t i o n a f t e r shutdown i s d i f f i c u l t to estimate, I f the s h i e l d is not d i s a s s e m b l e d , rough e s t i m a t e s i n d i c a t e

t h a t the Inconel a c t i v a t i o n should not be a problem.

H e r e a g a i n , t h e ARE w i l l y i e l d much v a l u a b l e i n f o r m a t i o n .

The s h i e l d f o r t h e 200-megawatt r e f l e c t o r - m o d e r a t e d r e a c t o r h a s some c h a r a c t e r i s t i c s t h a t are p e c u l i a r t o t h i s particular reactor configuration.

A s i n d i c a t e d i n an e a r l i e r s e c t i o n , t h e t h i c k r e f l e c t o r w a s s e l e c t e d on the b a s i s of s h i e l d i n g considerations.(') The two m a j o r r e a s o n s f o r using a thick reflector are that a r e f l e c t o r about 12 i n , t h i c k f o l l o w e d by a l a y e r of b o r o n - b e a r i n g m a t e r i a l w i l l attenuate the neutron flux t o t h e p o i n t w h e r e t h e s e c o n d a r y gamma f l u x c a n be r e d u c e d t o a n u n i m p o r t a n t level for a quasi-unit shell.

This thickness a l s o reduces the neutron leakage f l u x from t h e r e f l e c t o r t o the heat exchanger t o the l e v e l of t h a t from t h e d e l a y e d n e u t r o n s a p pearing in the intermediate heat e x c h a n g e r a s d e l a y e d n e u t r o n s from the circulating fuel.

An a d d i t i ' o n a l advantage of the t h i c k r e f l e c t o r is t h a t 99.98% o f t h e e n e r g y d e v e l o p e d in the core w i l l appear a s heat i n t h e h i g h - t e m p e r a t u r e zone i n s i d e t h e pressure shell.

T h i s means t h a t v e r y l i t t l e of t h e e n e r g y produced by t h e r e a c t o r m u s t b e d i s p o s e d o f with a p a r a s i t i c c o o l i n g system a t a low t e m p e r a t u r e l e v e l .

The m a t e r i a l i n the spherical-shell intermediate h e a t exchanger is about 7 0 % a s e f f e c t i v e a s w a t e r f o r t h e removal of f a s t n e u t r o n s ; s o i t t o o i s of v a l u e from the shielding standpoint.

The d e l a y e d n e u t r o n s a n d t h e d e c a y gammas f r o m the circulating fuel in the heat exchanger r e g i o n might appear t o pose a serious handicap.

However, e a c h h a s an a t t e n u a t i o n l e n g t h t h a t i s much s h o r t e r than the corresponding attenua t i o n l e n g t h f o r r a d i a t i o n from t h e core.

Thus, from t h e o u t e r s u r f a c e of the s h i e l d , the intermediate heat e x c h a n g e r a p p e a r s a s a much l e s s (')A. P. F r a a s , T h r e e R e a c t o r - H e a t E x c h a n g e r S h i e l d A r r a n g e r e n t s f o r Use w i t h Fused F l u o r i d e C i r c u l a t i n g F u e l , OWL Y-F15-10 (June 3 0 , 1952).

75

ANP PROJECT QUARTERLY PROGRESS REPORT

.

i n t e n s e s o u r c e of r a d i a t i o n than t h e more d e e p l y b u r i e d r e a c t o r c o r e .

It is t r u e t h a t t h i s arrangement v i o l a t e s one of t h e p r e c e p t s o f t h e matched s h i e l d , namely, t h a t e a c h l a y e r of h e a v y m a t e r i a l s h o u l d be placed a s c l o s e t o the r e a c t o r core as possible.

However, t h e l o s s i n weight a s s o c i a t e d with t h e d i s p a r i t y between t h i s i d e a l c a s e and t h e s h i e l d layout of Fig. 4.32 is n o t t o o g r e a t , whereas t h e engineering advantages derived a r e of c r u c i a l importance.

A s e r i e s of L i d Tank e x p e r i m e n t s is i n p r o g r e s s t o d e t e r m i n e t h e optimum a r r a n g e m e n t a n d t h i c k n e s s o f t h e v a r i o u s beryllium, boron c a r b i d e , i r o n , l e a d , and b o r a t e d w a t e r l a y e r s f o r a s h i e l d o f t h e t y p e shown i n Fig. 4 . 3 2 , which r e p r e s e n t s t h e b e s t configuration tested t o date.

When t h i s series of tests is completed, t h e r e s u l t i n g s h i e l d w i l l be u s e d a s a b a s i s f o r comparison, Further tests w i l l b e run withmore unusual materials.

Rough c a l c u l a t i o n s i n d i c a t e t h a t a s much a s 1 0 , 0 0 0 l b o f s h i e l d w e i g h t might be saved through t h e use of some o f t h e s p e c i a l m a t e r i a l s .

When t h e t e s t work i s c o m p l e t e d , i t i s hoped t h a t a f a i r l y sound b a s i s f o r a d e c i s i o n on t h e u s e o f t h e s e s p e c i a l m a t e r i a l s w i l l be p r o v i d e d b y a comp a r i s o n o f t h e i r c o s t and a t t e n d a n t weight savings r e l a t i v e t o the simpler s h i e l d c o n f i g u r a t i o n of Figure 4.32.

One o f t h e m a j o r p i e c e s o f i n f o r m a t i o n o b t a i n e d from t h e L i d Tank experiments has been t h e c o n f i r m a t i o n of t h e o r i g i n a l e s t i m a t e s of the d e g r e e of a c t i v a t i o n of sodium i n t h e heat exchanger region.

I t had been suspected that in a relatively thin s l a b of m a t e r i a l h a v i n g t h e poor m o d e r a t i n g p r o p e r t i e s of t h e h e a t e x c h a n g e r m a t r i x , n e u t r o n s o f 0 . 1 Mev o r h i g h e r would t e n d t o e s c a p e from t h e s l a b l o n g b e f o r e t h e y c o u l d be s l o w e d down. A l t h o u g h i t i s n o t p o s s i b l e t o s i m u l a t e t h e e f f e c t s of t h e c i r c u l a t i n g f u e l i n t h e L i d Tank e x p e r i -

76

ments, the spectrum of the delayed n e u t r o n s is n o t t o o d i f f e r e n t from t h a t of t h e bulk of the neutrons t h a t escape from t h e f u e l r e g i o n through t h e t h i c k b e r y l l i u m r e f l e c t o r and t h e heavy boron c a r b i d e c u r t a i n between t h e r e f l e c t o r and t h e h e a t exchanger.

For t h i s reason, i t is f e l t t h a t t h e sodium a c t i v a t i o n d a t a from t h e Lid Tank e x p e r i m e n t s g i v e a good b a s i s f o r e s t i m a t i n g t h e a c t i v a t i o n o f t h e sodium i n a f u l l - s c a l e reactor of the type shown i n F i g . 4 . 2 5 .

On t h i s b a s i s , it appears t h a t t h e sodium a c t i v i t y a f t e r a long period of full-power output w i l l give a dose of about 1 r / h r a t 50 f t from t h e r e a c t o r .

The a c t i v i t y of t h e p o t a s s i u m i n t h e NaK w o u l d b e much l e s s t h a n t h a t o f t h e sodium.(") The NaK c o u l d be d r a i n e d a f t e r o p e r a t i o n and t h e a c t i v a t e d sodium allowed t o decay.

Several weeks s h o u l d s u f f i c e t o b r i n g t h e a c t i v i t y o f t h e s o d i u m down t o a n e g l i g i b l e l e v e 1.

The d e s i g n d e s c r i b e d i s b e l i e v e d t o g i v e enough s h i e l d i n g a l l around t h e r e a c t o r t o g i v e a d o s e of 5 r / h r a t 50 f t from t h e c e n t e r o f t h e r e a c t o r a t f u l l power.

An a d d i t i o n a l l e a d l a y e r w o u l d be e m p l o y e d a t t h e f r o n t of the r e a c t o r t o a c t a s a l i g h t shadow s h i e l d f o r t h e crew.

Further shadow s h i e l d i n g would be employed a t t h e back of t h e crew compartment t o a t t e n u a t e t h e r a d i a t i o n from b o t h t h e r e a c t o r a n d t h e NaK r a d i a t o r s t o give a dose of approximately 1 r / h r i n s i d e t h e crew compartment.

Tables 4 . 5 and 4 . 6 g i v e d e t a i l e d d a t a f o r such a configuration for several r e a c t o r c o r e d i a m e t e r s , power o u t p u t s , and power d e n s i t i e s .

Further w o r k c o v e r i n g t h e e f f e c t s on s h i e l d weight of various dose l e v e l s f o r b o t h g r o u n d and f l i g h t crews i s u n d e r way. ('O'W. K. Ergen, P o t a s s i u m a s C o o l a n t in C o n n e c t i o n w i t h G r o u n d - S a f e S h i e l d s , ORNL Y - F 2 0 - 4 ( D e c . 6 , 1950).

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e

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w.

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0

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5

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0

c

m

L

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73

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TABLE 4 . 5 .

D O S A G E S A T V A R I O U S L O C A T I O N S FOR THE S H I E L D O F T A B L E 4 . 6 DOSE

LOCATION

At S t a r t up*

(r/hr) A t Shutdown**

At Full Power

NaK n o t Drained

NaK Drained

50 f t from r e a c t o r ( e x c e p t i n f r o n t cone)

0.5

6

1

0.1

Crew compartment

0.1

1

0.2

0.02

1 6 f t from r e a c t o r ( e x c e p t i n f r o n t cone)

6

60

10

1

60

600

30

10

Shield surface (except i n f r o n t cone) 'Ten p e r c e n t o f f u l l power.

* * F i f t e e n m i n u t e s a f t e r shutdown from long p e r i o d a t f u l l power.

T A B L E 4 . 6 . P R E L I M I N A R Y S H I E L D WEIGHT E S T I M A T E S SHOWING E F F E C T S O F V A R I A T I O N S I N REACTOR POWER, C O R E D I A M E T E R , AND POWER D E N S I T Y I N T H E F U E L R E G I O N *

Power, m e g a w a t t s

22.7

18

Reactor corediameter, in.

Power d e n s i t y , kw/cm3

2 00

200

2.79

5.5

Pressure s h e l l outside diameter, in.

59

62.3

Lead l a y e r o u t s i d e diameter, in.

72

75.3

Reactor s h i e l d outside diameter, in.

Total weight, reactor, heat exchanger,and shield, lb Shadow d i s k a t crew (7 f t d i a l , l b

400 22.7 5*5 68.8 82

200

400

800

28.5

28.5

28.5

1 37.

2.75

5.5

66.6

72.4

81.6

79.6

85.4

94.6

e

121

129.5

140

119

128

74,000

84,000

108,000

93,000

115,000

147,000

3,600

3 ,600

3,600

3,600

3,600

3,600

120

*Computed from L i d Tank d a t a for the b e s t Be-B4C-NaF-B4C-Fe-Pb-HZ0 l a y e r c o n f i g u r a t i o n t e s t e d up t o l a r c h 13. 1953.

POWER P L A N T D E S I G N

A . P. F r a a s , ANP D i v i s i o n Some e a r l y w o r k on n u c l e a r p o w e r plants involved d e t a i l e d designs of power p l a n t s i n which t h e e n g i n e s w e r e w i d e l y s e p a r a t e d from t h e r e a c t o r . The a c u t e problems of d i f f e r e n t i a l t h e r m a l

expansion, t h e r m a l l a g and system c o n t r o l , and t h e plumbing weight associated with these arrangements i n d i c a t e d t h a t i t w o u l d be a d v a n t a g e o u s t o use compact u n i t s .

Thus, the c u r r e n t t r e n d t o w a r d compact power p a c k a g e s , f o l l o w e d by b o t h t h e G e n e r a l E l e c t r i c Co. and t h e P r a t t and Whitney A i r c r a f t D i v i s i o n , seems i n o r d e r .

79

ANP PROJECT QUARTERLY PROGRESS REPORT I n c o n s i d e r i n g t h e t y p e s of a p p l i cation of greatest interest, it appeared t h a t t h e r e are t h r e e r e p r e s e n t a t i v e c a s e s : n a m e l y , a B-36 f l i g h t t e s t - b e d i n s t a l l a t i o n , a Mach 0.9 s e a l e v e l b o m b e r , a n d a Mach 1 . 5 h i g h a l t i t u d e bomber.

In sketching prel i m i n a r y l a y o u t s , it appeared t h a t t h e r e was l i t t l e d i f f e r e n c e i n t h e r e q u i r e m e n t s f o r t h e f i r s t two, and the third differed i n not too serious a fashion.

As a result, the layout of F i g , 4.25 was p r e p a r e d f o r t h e Mach 0 . 9 s e a - l e v e l bomber o n t h e b a s i s t h a t i t would r e q u i r e a r e a c t o r h e a t o u t p u t of 200 megawatts.

I t was presumed t h a t t h e same power p l a n t m i g h t be u s e d f o r p r e l i m i n a r y t e s t work a t a r e d u c e d p o w e r , s a y 1 3 0 m e g a w a t t s , i n a B-36 f l i g h t - t e s t - b e d installation.

T a b l e 4 . 7 g i v e s t h e w e i g h t of v a r i o u s components o f t h e i n s t a l l a t i o n shown i n F i g . 4 . 3 3 . ' I f a n i n c r e a s e i n power w e r e made, t h e w e i g h t o f t h e reactor-heat-exchanger-shield assembly would i n c r e a s e a s i n d i c a t e d i n T a b l e 4.6, and the weight of engines, r a d i a t o r s , pumps, a n d l i n e s w o u l d b e r o u g h l y p r o p o r t i o n a l t o t h e power output.

I f t h e same power o u t p u t were TABLE 4 . 7 .

t o be r e q u i r e d a t a n a l t i t u d e a t w h i c h the air-swallowing c a p a c i t y of t h e e n g i n e s was c u t i n h a l f , t h e t u r b o j e t e n g i n e w e i g h t would be d o u b l e d .

The w e i g h t of t h e r a d i a t o r s w o u l d be i n c r e a s e d by, p e r h a p s , 5 0 % , b u t t h e w e i g h t o f t h e pumps a n d l i n e s w o u l d r e m a i n s u b s t a n t i a l l y t h e same.

The power p l a n t o f F i g . 4..33 r e p r e s e n t s o n l y a p r e l i m i n a r y l a y o u t f o r showing t h e p r o p o r t i o n s t h a t m i g h t be e x p e c t e d .

The t h r u s t t h a t c a n be o b t a i n e d f r o m t h i s power p l a n t i s h e a v i l y d e p e n d e n t on t h e a l l o w a b l e r e a c t o r o p e r a t i n g temperature.

By c a r e f u l d e s i g n o f t h e m o d e r a t o r - c o o l i n g system, it w i l l be p a s s i b l e t o keep t h e temperature of a l l s t r u c t u r a l p a r t s down t o t h e temperature of the secondary f l u i d leaving the intermediate heat exc h a n g e r . T h i s s h o u l d make i t p o s s i b l e t o o p e r a t e s u c h a power p l a n t , c o n s t r u c t e d o f I n c o n e l , a t NaK o u t l e t t e m p e r a t u r e of a b o u t 1500'F f o r 500 hours.

A t a k e - o f f or war-emergency r a t i n g o f 1600'F m i g h t b e p e r m i t t e d f o r p e r h a p s 2 0 t o 50 h r o f t h e 500 hours.

A brief description o f t h e essential f e a t u r e s o f t h e d e s i g n shown i n F i g .

4.33 f o l l o w s , The r e a c t o r i s t h e same

c

MAJOR WEIGHT COMPONENTS OF THE 200-MEGAWATT AIRCRAFT POWER P L A N T O F F I G . 4 . 3 3 i

NO. OF UNITS 4

Turbojet engines

(lb)

12,400

16

R a d i a t o r s ( f i l l e d w i t h NaK)

6,000

16

NaK pumps, h e a d e r t a n k s , and t u r b i n e d r i v e a s s e m b l i e s

1,600

16

P i p i n g f o r NaK c i r c u i t s

2,000

T h e r m a l i n s u l a t i o n f o r NaK c i r c u i t s

1,300

NaK i n NaK c i r c u i t s ( e x c e p t i n r a d i a t o r s )

2,400

4

80

COMPONENTS

WEIGHT

F u e l and sodium pump d r i v e s

300

T u r b o j e t i n l e t and o u t l e t d u c t s and s u p p o r t s t r u c t u r e

8,000

T o t a l power p l a n t w e i g h t e x c l u d i n g r e a c t o r a n d s h i e l d

34,000

t

:

(4

,

,I

fEGQer DWG. ( 8 7 4 4

FUEL PUMP DRIVE TURBINE

BLEED-OFF AIR

No PUMP DRIVE TURBIN

NaK EXPANSION TANK NaK TO INTERMEDIATE HEAT E XC HANGER ( 14013째F)

-

WEB OF CANTILEVER BEAM FROM REAR WING SPAR BLEED-OFF AIR

XTERNAL SHIELD (RUBBER CONTAINER FILLED WITH BORATED WA TER)

-

LEAD SHIELD

NaK TO ENGINES (1500'F)

f JET

TAIL PIF'E

0 U

n ENGINE DATA

NoK-TO-AIR

MODIFIED WRIGHT TURBOJET COMPRESSION RATIO 4 I (CORRECTED FOR SEA LEVEL) AIR FLOW 220 Ib/sec (CORRECTED FOR SEA LEVEL) DIAMETER = 44 in.

LENGTH = 140 in

Fig.

z

c,

HELICAL BAFFLE

4

v2

ENGINE WEIGHT = 3100 Ib (WITHOUT RADIATOR) RADIATOR WEIGHT = 4500 Ib (WITH NaK)

RADIATOR

COMPRESSOR INLET AIR

4.33.

A i r c r a f t Power P l a n t ( 2 0 0 Megawatt).

z n

3:

ANP PROJECT QUARTERLY PROGRESS REPORT a s t h a t shown i n F i g . 4.25.

The s h i e l d was d e s i g n e d s o t h a t i t m i g h t be i n s e r t e d through an opening 6 f t 8 i n . wide i n t h e bottom of t h e f u s e lage, Thus i t would lend i t s e l f t o i n s t a l l a t i o n i n t h e bomb b a y o f t h e B-36 j u s t a f t o f t h e main s p a r .

Two c a n t i l e v e r beams p l a c e d o n 6 - f t c e n t e r s were employed a s t h e p r i m a r y s t r u c t u r e .

The f r o n t e n d s o f t h e s e beams c o u l d be b o l t e d or p i n n e d t o f i t t i n g s on t h e r e a r s p a r , and t h e r e a c t o r and t h e s h i e l d s t r u c t u r e c o u l d be a t t a c h e d t o t h e r e a r ends.

The s h i e l d s t r u c t u r e would be d i v i d e d i n t o s i x major s e c t i o n s , e a c h of w h i c h would c o n s i s t of an i n n e r l a y e r of l e a d and an o u t e r t a n k o f r u b b e r t h a t w o u l d be f i l l e d with borated water.

The t o p and b o t t o m s e c t i o n s would be s e p a r a t e d f r o m the four sections i n the central r e g i o n by s u r f a c e s o f r e v o l u t i o n f o r e n c l o s i n g t h e NaK d u c t s t h r o u g h t h e s h i e l d , A l a r g e , bowl-shaped, rubber t a n k w o u l d be p l a c e d a t e a c h s i d e .

T h e s e t a n k s c o u l d be d e f l a t e d w h i l e t h e power p l a n t was b e i n g i n s e r t e d i n t h e a i r p l a n e a n d c o u l d be f i l l e d w i t h w a t e r a f t e r t h e power p l a n t was i n place.

The t o p s e c t i o n o f t h e s h i e l d w o u l d b e p e n e t r a t e d by f i v e t u b e s .

F o u r o f t h e s e t u b e s would c a r r y q u i l l s h a f t s t o t r a n s m i t power f r o m b l e e d o f f a i r t u r b i n e s t o t h e pumps a t t h e t o p of t h e r e a c t o r , and t h e f i f t h tube would c a r r y t h e c o n t r o l rod a c t u a t i n g mechanism.

E a c h o f t h e e n g i n e r a d i a t o r s would be c o u p l e d t o a s e p a r a t e t u b e b u n d l e i n t h e intermediate heat exchanger i n s u c h a way t h a t t h e r e w o u l d be 1 6 separate secondary f l u i d circuits.

T h e e x p a n s i o n t a n k , f i l t e r , a n d pump f o r e a c h of t h e s e c i r c u i t s would be l o c a t e d a t t h e p o i n t of g r e a t e s t e l e v a t i o n and l o w e s t t e m p e r a t u r e i n the system, t h a t i s , a t the top of t h e s h i e l d and j u s t o u t s i d e i t . Thus t h e NaK w o u l d l e a v e t h e p u m p s a n d pass i n t o the s h i e l d , through the i n t e r m e d i a t e h e a t exchanger , back out

82

t h r o u g h t h e s h i e l d down t o t h e r a d i a t o r , a n d b a c k u p t o t h e pump.

The p i p e s passing t o and from t h e r a d i a t o r would be a p p r o x i m a t e l y 3 1 / 2 i n . i n diameter.

The p r e s s u r e d r o p t h r o u g h t h e r a d i a t o r s w o u l d be a b o u t 3 5 p s i , a n d t h a t t h r o u g h p i p e s from t h e r e a c t o r would be a b o u t 7 p s i , In a l l cases, t h e p r e s s u r e h a s b e e n k e p t low t o k e e p t h e s t r e s s e s low a n d , h e n c e , t o minimize t h e l i k e l i h o o d of a b u r s t type of f a i l u r e .

Thus, even t h o u g h small l e a k s might occur a s a r e s u l t of f a t i g u e cracks or small c o r r o s i o n p i t s i n welded o r b r a z e d j o i n t s , it seems l i k e l y t h a t a m a j o r l e a k ( e x c e p t f o r g u n f i r e ) c o u l d be a v o i d e d .

The t u r b o j e t e n g i n e s i n d i c a t e d i n F i g . 4 . 3 3 a r e m o d i f i c a t i o n s o f a new e n g i n e b e i n g d e v e l o p e d by t h e W r i g h t Aeronautical Corp.

The o r i g i n a l engine i s a high-compression-ratio t w o - s p o o l machine.

S i n c e f u e l economy is less important than engine weight f o r a power p l a n t of t h e t y p e s h o w n , ( ’ ’ ) an estimate of the weight o f a m o d i f i e d e n g i n e was p r e p a r e d by t h e W r i g h t A e r o n a u t i c a l C o r p O , and e s t i m a t e d performance curves f o r t h e s e engines a r e g i v e n i n F i g . 4.34.

The r a d i a t o r s used i n t h e s e t u r b o j e t s a r e of t h e same t y p e a s t h o s e t h a t have b e e n t e s t e d a t ORNL i n t h e f o r m o f c o r e elements during t h e p a s t year.

One o f these r a d i a t o r cores operated f o r over 1000 h r a t 1 5 0 0 ° F , o r a b o v e , i n c l u d i n g o v e r 40 h r a t 170O0F.(”) It is e x p e c t e d t h a t d e v e l o p m e n t a l work now i n p r o c e s s w i l l produce l i g h t e r u n i t s with b e t t e r h e a t t r a n s f e r performance than t h e r a d i a t o r s of t h i s p r e l i m i n a r y designe The p r o c e d u r e t h a t m i g h t be f o l l o w e d t o a s s e m b l e t h e c o m p l e t e power p l a n t w o u l d be t o m o d n t t h e r e a c t o r on t h e c a n t i l e v e r beams t h a t s u p p o r t i t a n d the s h i e l d assembly.

The t u r b o j e t e n g i n e s would t h e n be mounted t o S. F a r m e r , A . P. F r a a s , H. J . S t u m p f , Whitman, P r e l i m i n a r y D e s i g n a n d P e r fornance Studies of Sodiun-to-Air Radiators, (‘”W. a n d G . D.

OWL-1509 ( t o b e p u b l i s h e d ) .

i

.

PERIOD ENDING MARCH 1 0 , 1 9 5 3

I

1

I

I

I

1

I

CORRECTED COMPRESSION RATIO

I

I

= 4.0 : 1

320

280 240 200 I60 t 20

80 40

RADIATOR W E I G H T = i500 I b RADIATOR D E P T H = 12 in.

64,000 c

56,000

Y .

48,000

2 z

40,000

= I

32,000

8

+ 24,000

a W

I

16,000

8000

12,000

-c

10,000

n

m

8000

2

6000 i-f

2

4000

i 0 -

2000 I

0

0

Fig. 4.34.

0.3

0.6

0.9 MACH N U M B E R

1.2

1.5

E s t i m a t e d Turbo j e t Engine P e r f o r m a n c e C u r v e s .

83

,--,

s t r u c t u r e a t t a c h e d t o t h e s e same c a n t i l e v e r beams, The p i p e s c o n n e c t i n g the engine radiator t o the reactor and h e a t e x c h a n g e r a s s e m b l y c o u l d t h e n be welded i n t o p o s i t i o n , a l o n g w i t h theNaK pump and h e a d e r t a n k a s s e m b l i e s , The e n t i r e s y s t e m c o u l d t h e n be p r e s s u r e c h e c k e d c a r e f u l l y a n d examined closely f o r leaks.

I t would p r o b a b l y p r o v e d e s i r a b l e t o i n s t a l l NaK i n t h e secondary c i r c u i t , sodium i n t h e m o d e r a t o r c i r c u i t , o p e r a t e t h e pumps, and c h e c k a l l components c a r e f u l l y f o r leaks before the thermal i n s u l a t i o n was i n s t a l l e d .

An a u x i l i a r y s u p p l y o f c o m p r e s s e d a i r w o u l d be r e q u i r e d t o r u n t h e s o d i u m a n d NaK pumps a t perhaps h a l f speed f o r t h i s check.

The s y s t e m t e m p e r a t u r e s i n t h e NaK c i r c u i t s would n o t have t o e x c e e d room temperature, but an auxiliary burner a r r a n g e m e n t s h o u l d be p r o v i d e d t o h e a t t h e two r a d i a t o r s c o u p l e d t o t h e two sodium-to-NaK h e a t exchangers f o r t h e moderator c o o l i n g system.

These h e a t e r s c o u l d be u s e d t o b r i n g t h e sodium s y s t e m t e m p e r a t u r e up t o 300 or 400째F. Upon s a t i s f a c t o r y c o m p l e t i o n o f t h i s t e s t work, t h e r m a l i n s u l a t i o n c o u l d be i n s t a l l e d a r o u n d t h e r e a c t o r p r e s s u r e s h e l l and t h e connecting l i n e s and pumps o f t h e s o d i u m c i r c u i t .

By u s i n g t h e s a m e h e a t s o u r c e , t h e s o d i u m s y s t e m c o u l d be b r o u g h t u p t o perhaps 1000째F and a nonuraniumb e a r i n g f l u o r i d e s a l t c o u l d be pumped into the reactor.

The f l u o r i d e - f u e l system could t h e n be checked and d r a i n e d , and t h e l e a d s h i e l d i n g and t h e rubber tanks f o r the borated water c o u l d be i n s t a l l e d t o c o m p l e t e t h e a s s e m b l y , A f t e r t h e power p l a n t u n i t had been i n s t a l l e d i n t h e a i r p l a n e , t h e r u b b e r t a n k s c o u l d be f i l l e d w i t h borated w a t e r , and t h e n e c e s s a r y c o n n e c t i o n s c o u l d b e made f o r t h e i n s t r u m e n t s and c o n t r o l s ,

84

I n s t a r t i n g up t h e r e a c t o r , it is e x p e c t e d t h a t t h e NaK c i r c u i t s w o u l d be u s e d t o h e a t t h e s o d i u m t o b r i n g t h e r e a c t o r t e m p e r a t u r e up t o about 1000째F. A f l u o r i d e f u e l m e l t cont a i n i n g l e s s t h a n t h e d e s i r e d amount o f u r a n i u m would t h e n be p o u r e d i n t o the f u e l system and c i r c u l a t e d .

Gradual a d d i t i o n s of a f l u o r i d e m e l t containing a r a t h e r high percentage of U 2 3 5 c o u l d be made u n t i l t h e r e a c t o r became c r i t i c a l .

The t e m p e r a t u r e of t h e r e a c t o r c o u l d t h e n be a l l o w e d t o increase t o the desired value probably a n a v e r a g e t e m p e r a t u r e of 1300'F - a n d t h e l o a d c o u l d b e g r a d u a l l y i n c r e a s e d by s t a r t i n g up f i r s t one and t h e n a n o t h e r of t h e t u r b o j e t engines.

I t w i l l p r o b a b l y be p o s s i b l e t o depend upon t h e s e l f - s t a b i l i z i n g characteristics inherent in the fluoride f u e l reactor t o keep the mean f l u o r i d e t e m p e r a t u r e e s s e n t i a l l y constant so that, i n effect, the r e a c t o r w o u l d become a s l a v e t o t h e t u r b o j e t e n g i n e s and would a c t a s a c o n s t a n t t e m p e r a t ur e h e a t s o u r c e .

Control of the individual turbojet e n g i n e s c o u l d b e a c c o m p l i s h e d by v a r y i n g t h e amount o f a i r a l l o w e d t o bypass the r a d i a t o r s through a d j u s t a b l e l o u v e r s i n t h e h e l i c a l b a f f l e s between r a d i a t o r banks.

I n e f f e c t , t h i s would g i v e a v a r i a b l e , mean, t u r b i n e - a i r i n l e t temperature.

Coupled w i t h t h i s c o n t r o l , it would p r o b a b l y be n e c e s s a r y t o have an a d j u s t a b l e j e t e x i t n o z z l e t o g i v e good p e r f o r m a n c e a n d t o a v o i d compressor s t a l l o v e r a wide range of operating conditions.

Fine c o n t r o l of r e a c t o r t e m p e r a t u r e c o u l d be a c c o m p l i s h e d t h r o u g h t h e u s e of one or t w o c o n t r o l r o d s i n t h e c e n t r a l island or i n the r e f l e c t o r region.

C o a r s e s h i m c o n t r o l c o u l d be o b t a i n e d by v a r y i n g t h e uranium c o n c e n t r a t i o n i n the fluoride fuel.

-

i

'C

5

.

..

..

.

..-.

INTRODUCTION AND SUMMARY E . P. B l i z a r d

J. L. M e e m , A s s o c i a t e

Physics Division With t h e development o f a r e a c t o r design i n which t h e f i s s i o n s a r e c o n f i n e d t o a s m a l l volume, and i n which it i s hoped t h e r a d i a t o r s can be k e p t r e l a t i v e l y nonradioactive, t h e hopes for a l i g h t u n i t s h i e l d h a v e been revived.

Accordingly, a u n i t - s h i e l d mockup w a s r e c e n t l y i n s t a l l e d i n t h e L i d Tank F a c i l i t y and i s now b e i n g o p t i m i z e d w i t h r e g a r d t o t h e l o c a t i o n o f t h e s h i e l d components.

I n a d d i t i o n , an i n t e n s i v e search is being carried out for promising materials t h a t could be u s e d i n t h e u n i t s h i e l d . Measurements of r e l a t i v e s h i e l d i n g e f f e c t i v e n e s s indicate lithium t o be a promising component f o r n e u t r o n s h i e l d i n g , and i n q u i r i e s have been i n i t i a t e d t o determine whether uranium could be made a v a i l a b l e and f a b r i c a t e d a s a gamma s h i e l d ( s e c . 5 ) .

The a i r - s c a t t e r i n g e x p e r i m e n t s a t the Bulk S h i e l d i n g F a c i l i t y have been completed. E a r l i e r d i f f i c u l t i e s have been a s c r i b a b l e p r i m a r i l y t o u n s u s p e c t e d background e f f e c t s , and i n d i c a t i o n s now a r e t h a t t h e w e i g h t s d e s c r i b e d i n t h e r e p o r t of t h e S h i e l d i n g Board (1950) were approximately correct.

The n e u t r o n s were s o m e w h a t l o w and t h e gam'ma r a y s somewhat h i g h , with the weight d i f f e r e n c e s approximately cancelling.

The i r r a d i a t i o n of a n i m a l s i n t h e Bulk S h i e l d i n g F a c i l i t y i s now c o m p l e t e , a n d t h e

a n i m a l s i n v o l v e d h a v e been r e t u r n e d f o r long-range observation of t h e b i o l o g i c a l e f - f e c t s of t h e s e e x p o s u r e s .

N e u t r o n s p e c t r o s c o p y on t h e d i v i d e d s h i e l d i n t h e Bulk S h i e l d i n g F a c i l i t y h a s now commenced, a n d t h e f i r s t f e w s p e c t r a have been measured w i t h t h e proton-recoil spectrometer.

The r e s u l t s are only p r e l i m i n a r y ; hence, no d a t a a r e y e t a v a i l a b l e .

However, t h e gamma s p e c t r a l m e a s u r e m e n t s f r o m t h e d i v i d e d - s h i e l d mockup a r e b e i n g t a b u l a t e d f o r machine c a l c u l a t i o n s (sec. 6 ) .

The Tower S h i e l d i n g F a c i l i t y d e s i g n is being developed rapidly.

The t o w e r s t r u c t u r e d e s i g n i s f i n a l and a building is f a i r l y completely l a i d out.

The R e a c t o r d e s i g n f e a t u r e s and some o f t h e i n s t r u m e n t a t i o n a:re y e t t o be developed.

I n d i c a t i o n s are t h a t t h e f a c i l i t y w i l l begin operation by t h e e n d o f t h e c a l e n d a r y e a r , a n d tests with the f i r s t s h i e l d s w i l l commence s h o r t l y t h e r e a f t e r ( s e c . 7 ) .

A neutron spectrometer is being d e v e l o p e d t h a t , u t i li z e s s c i n t i 11a t i o n i n a lithium fluoride crystal.

This apparatus gives promise of appreciably g r e a t e r s e n s i t i v i t y than recoil-proton spectrometers i f developmental d i f f i c u l t i e s c a n be overcome.

No c r o s s s e c t i o n m e a s u r e m e n t s were c o m p l e t e d o n t h e 6-Mev Van d e G r a a f f d u r i n g t h e q u a r t e r b e c a u s e t h e m a c h i n e was b e i n g moved t o i t s p e r m a n e n t l o c a t i o n i n t h e X-10 A r e a ( s e c . 8).

87

.

6

f

5.

L I D TANK FACILITY

J . D. F l y n n G. T. Chapman

J . N. M i l l e r F. N. Watson

Ph ys i c s D i v i s i on The L i d Tank F a c i l i t y h a s b e e n used during t h e past q u a r t e r primarily f o r m e a s u r i n g t h e f a s t - n e u t r o n remova 1 c r o s s s e c t i o n s o f a number of conv e n t i o n a l and p o t e n t i a l s h i e l d i n g materials.

I n a d d i t i o n , a mockup o f t h e u n i t s h i e l d of t h e r e f l e c t o r m o d e r a t e d r e a c t o r h a s been a s s e m b l e d .

EFFECTIVE FAST-NEUTRON REMOVAL CROSS SECTIONS The f o l l o w i n g e f f e c t i v e f a s t n e u t r o n removal c r o s s s e c t i o n s have been measured: A1 1.19 b a r n s / a t o m

Be

1.12 barns/atom

cu

2.08 b a r n s / a t o m

Fe LiF

1 . 9 3 barns/atom 2.8 0 b a r n s /m o 1ecu 1e 3 . 0 8 b a r n s / a tom

w

T h e d a t a on l i t h i u m f l u o r i d e a r e particularly interesting.

I f fluorine is assigned a cross section of 1 b a r n , a s would b e i n d i c a t e d from a comparison with p r e v i o u s l y measured v a l u e s for o x y g e n a n d c a r b o n , i t would a p p e a r t h a t l i t h i u m e x h i b i t s a c r o s s s e c t i o n of 1.8 barns.

This i s e x c e p t i o n a l l y high f o r such a l i g h t n u c l e u s , and, i f v e r i f i e d , r e v e a l s a r e a l incentive f o r using t h i s element i n a i r c r a f t shields.

Accordingly, i t i s planned t o measure t h e c r o s s s e c t i o n o f f l u o r i n e a s s o o n a s p o s s i b l e by u s i n g s l a b s of a saturated fluorocarbon.

M e a s u r e m e n t s h a v e a l s o been made on t h e e f f replacing water n e a r t h e s o u r c e w i t h a s l a b of t r a n s f o r m e r o i l (CH,).

By c o m p a r i s o n o f t h e s e measurements w i t h t h o s e f o r g r a p h i t e , i t i s possible t o determine the e f f e c t o f t h e oxygen t h a t t h e o i l r e p l a c e d i n the water close t o the source.

T h i s r e p r e s e n t s t h e f i r s t measurement o f t h e t r u e e f f e c t i v e removal. c r o s s s e c t i o n f o r t h i s element.

Previous e s t i m a t e s h a v e b e e n d e p e n d e n t upon a somewhat d i f f e r e n t d e f i n i t i o n , b e c a u s e t h e oxygen t h a t was measured w a s spread throughout t h e shield as i n water.

It is i n t e r e s t i n g t o note t h a t , a s m i g h t b e e x p e c t e d , t h e oxygen e x h i b i t s a somewhat g r e a t e r e f f e c t i v e removal c r o s s s e c t i o n i n t h e l o c a t i o n n e a r t h e source.

It had b e e n p r o p o s e d by S l e e p e r o f Brookhaven N a t i o n a l L a b o r a t o r y t h a t d e u t e r i u m m i g h t p r o v e a more e f f e c t i v e s h i e l d component t h a n h y d r o g e n b e c a u s e o f t h e more n e a r l y i s o t r o p i c s c a t t e r i n g (laboratory system) it exhibits b e c a u s e of i t s i n c r e a s e d mass.

To e x p l o r e t h i s p o i n t , a t a n k o f D,O was inserted next t o the source in t h e L i d Tank F a c i l i t y , and an e f â&#x201A;Ź e c t i v e removal c r o s s s e c t i o n w a s measured.

Results indicate a difference i n e f f e c t i v e removal cross section b e t w e e n n o r m a l and h e a v y hydr'ogen o f 0.1 barn.

This corresponds very closely to the difference i n t h e i r t o t a l c r o s s s e c t i o n s i n t h e r a n g e of a b o u t 2 t o 5 Mev and i n d i c a t e s t h a t n o a d d e d premium a c c r u e s from, t h e i n c r e a s e d a n g l e of s c a t t e r i n g o r , a t least, that t h i s is counterbalanced by t h e g r e a t e r e n e r g y d e g r a d a t i o n o f t h e l i g h t hydrogen.

MOCKUP OF THE UNIT SHIELD OF THE REFLECTOR-MODERATED REACTNOR R e c e n t l y a mockup h a s b e e n i n s t a l l e d i n t h e L i d Tank F a c i l i t y t o s i m u l a t e t h e r e f l e c t o r h e a t exchanger and t h e u n i t shield of the Fireball reactor.

The b e r y l l i u m r e f l e c t o r i s s i m u l a t e d by a l a r g e s l a b o f m a t e r i a l s u p p l i e d

by KAPL p l u s some a d d i t i o n a l m a t e r i a l

89

ANP PROJECT QUARTERLY PROGRESS REPORT t h a t w a s a v a i l a b l e a t t h e Y-12 s i t e .

T h e h e a t e x c h a n g e r i s s i m u l a t e d by sodium f l u o r i d e and i r o n ; t h e sodium f l u o r i d e i s loaded i n t o l a r g e , t h i n , i r o n boxes.

The p r o t o t y p e f o r t h e s h i e l d w i l l b e o f l e a d and w a t e r , a n d t e s t s c u r r e n t l y u n d e r way a r e d e s i g n e d t o d e t e r m i n e t h e optimum l o c a t i o n o f t h e l e a d within t h e water.

An i n v e s t i g a t i o n w i l l a l s o b e made o f t h e d e s i r a b i l i t y of b o r a t i n g p a r t of the water.

These experiments have j u s t begun, and t h e r e f o r e n o f i r m d a t a a r e y e t a v a i l a b l e ; however, t h e r e a r e indications that the over-all reactors h i e l d w e i g h t w i l l b e v e r y low.

This i s a d i r e c t r e s u l t o f t h e s m a l l volume t o which t h e f i s s i o n s a r e c o n f i n e d .

.

f

90

PERIOD ENDING MARCH 10, 1953 6.

J. R. M. K. H.

L. G. P. M. E.

BULK SHIELDING FACILITY Meem Cochran Haydon Henry Hungerford

E. J. T. F. G.

B. K. A. C. M.

Johnson Leslie Love Maienschein McCammon

Physics Division The a i r - s c a t t e r i n g e x p e r i m e n t s a n d t h e program o f i r r a d i a t i n g monkeys have been concluded.

In addition, some p r e l i m i n a r y n e u t r o n s p e c t r a l measurements h a v e b e e n made, b u t f u r t h e r work w i l l b e p o s t p o n e d u n t i l m e a s u r e m e n t s h a v e b e e n c o m p l e t e d on t h e mockup o f t h e t o p p l u g of t h e SIR s h i e l d .

T h e gamma s p e c t r a l m e a s u r e m e n t s on t h e r e a c t o r p a r t o f the divided shield a r e being applied t o c a l c u l a t i o n s of a d i v i d e d s h i e l d .

AIR-SCATTERING EqPERIMENTS The a i r - s c a t t e r i n g e x p e r i m e n t a t t h e Bulk S h i e l d i n g F a c i l i t y , o r i g i n a l l y c a r r i e d o u t l a s t s u m m e r , ( l o2 , h a s been extended and improved i n an effort t o understand the serious d i s c r e p a n c y t h a t a p p e a r e d t o be e x t a n t b e t w e e n t h i s e x p e r i m e n t and t h e c a l c u l a t i o n s of t h e S h i e l d i n g B o a r d . ( 3 ) With t h e i n c r e a s e d power now a v a i l a b l e , 1 0 0 kw h a v i n g r e c e n t l y b e e n a p p r o v e d f o r t h e BSR, i t i s now p o s s i b l e t o e l i m i n a t e much o f t h e e x t r a p o l a t i o n previously required.

In addition, i t was d i s c o v e r e d t h a t t h e r a d i o a c t i v i t y i n t h e D O O ~ w a t e r was r e s p o n s i b l e f o r a l a r g e p a r t of t h e o b s e r v e d d o s e i n t h e mocked-up crew p o s i t i o n .

Measurewer en t o d e t e r m i n e t h e of us radiations scatteri n g from t h e p o o l w a l l s , a s w e l l a s from t h e r e a c t o r suppo

T h e s e were f o u n d t o c o n t r i b u t e o n l y n e g l i g i b l y t o t h e o b s e r v e d n e u t r o n and gamma d o s e s .

A l t h o u g h t h e e x p e r i m e n t hiIs b e e n completed s o r e c e n t l y t h a t i t i s impossible a t t h i s t i m e t o give a complete r e p o r t , the following conc l u s i o n s c a n be drawn : 1. T h e n e u t r o n d o s e i n t h e c r e w c o m p a r t m e n t a p p e a r s t o b e l o w e r by a f a c t o r o f 5 t h a n t h e ANP-53 c a l c u lations indicate.

The a d v a n t a g e a c c r u i n g from t h i s amounts t o a b o u t 5000 l b f o r t h e s t a n d a r d c r e w - s h i e l d design 2. The gamma-ray d o s e i n t h e c r e w compartment a p p e a r s t o b e highler t h a n i n d i c a t e d by t h e ANP-53 d e s i g n by a f a c t o r of 3.5.

The w e i g h t p e n a l t y a s s o c i a t e d w i t h t h i s is a b o u t 6000 pounds.

The c o n c l u s i o n s d i f f e r from t h e e a r l i e r ones both i n t h e magnitude o f t h e d i s c r e p a n c i e s and i n t h e amount o f m a t e r i a l r e q u i r e d t o make u p t h e added a t t e n u a t i o n .

Since t h i s experi ment i s b a s i c a l l y s o v e r y c r u d e , f u r t h e r e x p l o i t a t i o n of t h e Bulk Shielding Facility i n t h i s type of work i s n o t c o n s i d e r e d w o r t h w h i l e ; t h e p r e s e n t c o m p a r i s o n w i t h t h e ANP-53 c a l c u l a t i o n s i s c o n s i d e r e d ad'equate.

.

-

IRRADIATION OF ANIMALS

( 2 ) J . L , Meem a n d H. E. H u n g e r f o r d , A i r S c a t t e r i n g Experiments a t t h e Bulk S h i e l d i n g F a c i l i t y , O W L C F - 5 2 - 7 - 3 7 ( J u l y 8. 1 9 5 2 ) .

I n a d d i t i o n t o t h e two g r o u p s o f monkeys mentioned i n a p r e v i o u s q u a r t e r l y r e p o r t , C 4 ) a t h i r d group h a s b e e n i r r a d i a t e d by t h e B u l k S h i e l d i n g Reactor.

The c o m p l e t e s e r i e s o f e x p e r i m e n t s i s summarized in T a b l e 6 . 1 .

( 3 ) R e p o r t of the ShieZding Board f o r the A i r c r a f t N u c l e a r P r o p u l s i o n P r o g r a m , ANP-53. p. 6 4 f f . ( O c t . 16, 1 9 5 0 ) .

(4)ANP Quar. P r o g . Rep. ORNL-1375, p . 6 6 .

("ANP p . 46.

Quar. P r o g . R e p . J u n e 10, 1952, O W L - 1 2 9 4 ,

Sept.

10,

1952,

91

ANP PROJECT QUARTERLY PROGRESS REPORT TABLE 6.1.

IRRADIATION OF MONKEYS IN THE BULK SHIELDING FACILITY

Number of e x p o s u r e s Time p e r e x p o s u r e , h r

Time between e x p o s u r e s , d a y s T o t a l e x p o s u r e , rem Number o f a n i m a l s u s e d * O n e - h a l f d o s e i n n e u t r o n s and o n e - h a l f d o s e i n gamma r a y s .

A l l exposures have been completed and t h e a n i m a l s h a v e b e e n r e t u r n e d t o t h e USAF S c h o o l o f A v i a t i o n M e d i c i n e a t A u s t i n , T e x a s , where t h e y w i l l be held f o r observation.

It i s expected t h a t t h e t h i r d g r o u p , which r e c e i v e d 512 r e m , w i l l d e v e l o p eye c a t a r a c t s , but t h a t t h e f i r s t and second groups w i l l not.

I f the experiment turns nticipated, the threshold f o r c a t a r a c t s should be d e f i n i t e l y bracketed.

A report is being prepared i n cooperation with the Health Physics D i v i s i o n t h a t g i v e s d e t a i l s of t h e dosimetry during the experiment.

F i g u r e 6. 1 s h o w s o n e o f t h e a n i m a l s r e a d y t o be p l a c e d i n a w a t e r t i g h t cage f o r submersion i n t h e pool.

GAMMA SPECTROSCOPY FOR THE DIVIDED SHIELD The d a t a on t h e e n e r g y and a n g u l a r d i s t r i b u t i o n of g a m m a r a y s from t h e d i v i d e d - s h i e l d mockup a r e b e i n g t a bu 1a t e d f o r mac h i n e c a 1c u 1a t i on s T h e e n e r g y , a n g u l a r d i s t r i b u t i o n , and t o t a l i n t e n s i t y of t h e d i r e c t , a s w e l l a s s c a t t e r e d , photons a r r i v i n g a t t h e crew compartment w i l l b e computed.

.

FISSION ENERGY AND POWER IN THE BULK SHIELDING REACTOR A r e p o r t on t h e p o w e r d i s t r i b u t i o n

s p e c t r o m e t e r d e v e l o p e d by C o c h r a n and H e n r y . ( ' ) Fast-neutron d a t a have a l s o been t a k e n with n u c l e a r p l a t e s and t h r e s h o l d d e t e c t o r s .

All results a r e i n p r e l i m i n a r y form and a r e n o t yet suitable for reporting.

The experiments w i l l be continued a s r e a c t o r time p e r m i t s .

i n t h e reactor with a beryllium oxide r e f l e c t o r h a s been c o m p l e t e d , ( 6 ) and a r e p o r t on t h e d e t e r m i n a t i o n o f t h e energy r e l e a s e d per f i s s i o n i s being prepared.

F i g u r e s 6 . 2 and 6 . 3 i l l u s t r a t e t h e t i m e decay of n e u t r o n s and gamma r a y s f r o m t h e r e a c t o r a f t e r shutdown.

The d a t a a r e n o r m a l i z e d t o u n i t y f o r o p e r a t i o n s a t 1 a n d 1 0 0 kw a n d p l o t t e d a g a i n s t t i m e a f t e r scramming the reactor.

It is interesting t o n o t e h o w t h e ( y , n > r e a c t i o n on b e r y l l i u m keeps the neutron l e v e l f a i r l y high.

Without t h e beryllium oxide r e f l e c t o r , t h e n e u t r o n s decay with p e r i o d s t h a t a r e characteristic of the delayedn e u t r o n emi t t e r s .

(5)R. G . C o c h r a n a n d K . M . H e n r y , A P r o t o n Reco i 1 T y p e Fas t - N e u t r o n S p e c t r o m e t e r , ORNL- 1479 (in press).

("J. L. Meem and E. B. J o h n s o n , D e t e r m i n a t i o n of the Power o f the Bulk S h i e l d i n g R e a c t o r , P a r t 11, ORNL-1438 ( i n p r e s s ) .

NEUTRON SPECTROSCOPY FOR THE DIVIDED SHIELD Some p r e l i m i n a r y n e u t r o n s p e c t r a klave b e e n r u n w i t h t h e p r o t o n - r e c o i l

f

PERIOD ENDING MARCH 10, 1953

Fig. 6.1. Monkey and Irradiation Cage f o r t h e Bulk Shielding Facility Experiment.

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7.

TOWER S H I E L D I N G F A C I L I T Y

C. E. C l i f f o r d

T. V. B l o s s e r

Physics Division

J. Y. E s t a b r o o k , ANP D i v i s i o n The p r e l i m i n a r y d e s i g n of t h e Tower S h i e l d i n g F a c i l i t y p r o p o s e d by t h e firm of Knappen-TippettsA b b e t t - M c C a r t h y (KTAM), a r c h i t e c t u r a l e n g i n e e r s , was a c c e p t e d by ORNL e a r l y i n J a n u a r y . Some d e l a y was n e c e s s i t a t e d by t h e d i s c o v e r y t h a t t h e t o w e r d e s i g n f i r s t c o n s i d e r e d b y KTAM p r o v e d exceptionally heavy i n s t r u c t u r a l steel, particularly i n t h e long o v e r h e a d members from which t h e l o a d s were s u p p o r t e d by a v e r t i c a l h o i s t .

S i n c e t h e h e a v i e r members r a i s e d t h e background from s t r u c t u r a l s c a t t e r i n g beyond r e a s o n a b l e l i m i t s , a d e s i g n was p r o p o s e d t h a t e 1i m i n a t e d t h e o v e r h e a d s t r u c t u r e and r e d u c e d t h e w e i g h t o f t h e l e g s by a f a c t o r o f a p p r o x i m a t e l y 2.

The d e s i g n s a n d s p e c i f i c a t i o n s o f t h e tower and a s s o c i a t e d b u i l d i n g s a r e now s c h e d u l e d f o r c o m p l e t i o n by KTAM a n d t h e ORNL E n g i n e e r i n g D e p a r t m e n t on March 1.

D e s i g n , p r o c u r e m e n t , and c o n s t r u c t i o n o f t h e r e a c t o r and i n s t r u ments, a s w e l l a s e n g i n e e r i n g o f t h e s i t e , r o a d , and u t i l i t i e s , a r e b e i n g done by ORNL. T h i s work i s p r o c e e d i n g a h e a d of s c h e d u l e , a t p r e s e n t .

r e a c t o r s h i e l d and f o u r f o r t h e c r e w shield.

The r e a c t o r s h i e l d c a n b e r a i s e d 200 f t o f f t h e g r o u n d , a n d i t may b e moved l a t e r a l l y t o a p p r o a c h t h e tower legs.

T h i s l a t e r a l movement w i l l p e r m i t measurement of t h e r a d i a t i o n s s c a t t e r e d by t h e t o w e r s t r u c t u r e .

The f o u r h o i s t s s u p p o r t i n g t h e crew c o m p a r t m e n t w i 11 a 1 1ow c on s i d e r a b l e f l e x i b i l i t y i n t h e crew c o m p a r t m e n t p o s i t i on a n d o r i e n t a t i o n , i n c l u d i n g t h e p o s s i b i l i t y of a v a r i a t i o n of f r o m 35 t o 1 0 0 f t i n t h e r e a c t o r - t o crew s e p a r a t i o n d i s t a n c e .

CONSTRUCTION SCHEDULE The t e n t a t i v e s c h e d u l e f o r o u t s i d e e n g i n e e r s and c o n t r a c t o r s f o r c o m p l e t i n g t h e i r v a r i o u s p h a s e s o f d e s i g n and c o n s t r u c t i o n o f t h e Tower S h i e l d i n g F a c i l i t y h a v e b e e n somewhat o p t i m i s t i c a l l y e s t i m a t e d as follows: F e b r u a r y 24

Design completed and s u b m i t t e d t o bidders

March 17

Bids received

March 20

C o n t r a c t s awarded

J u n e 15

C o n s t r u c t i o n o f t h e r o a d s , tower f o u n d a t i o n , a n d guy a n c h o r s completed

November 15

A 1 1 o u t s i d e constructioncom-

TOWER DESIGN The t o w e r d e s i g n i s shown i n Figs. 7 . 1 and 7.2.

The s t r u c t u r e i s 315 f t h i g h and h a s a 2 0 0 - f t i n s i d e clearance i n the north-south d i r e c t i o n and a 1 0 1 - f t i n s i d e c l e a r a n c e i n t h e east-west direction.

The f o u r t o w e r columns a r e 9 f t s q u a r e and weigh a p p r o x i m a t e l y 400 l b p e r r u n n i n g f o o t .

The l o a d s w i l l b e r a i s e d by s i x individual hoists two f o r t h e

-

December 31

pleted

,

Reactor c r i t i c a l

I t a p p e a r s t h a t ORNL w i l l e i t h e r meet o r b e a h e a d o f t h e t i m e s c h e d u l e i n i t s s h a r e o f t h e Tower S h i e l d i n g F a c i l i t y work.

The f o l l o w i n g i s a l i s t o f ORNLâ&#x20AC;&#x2122;s f u n c t i o n s , t o g e t h e r w i t h t h e p r e s e n t s t a t u s of acconiplishment

.

97

ANP PROJECT QUARTERLY PROGRESS REPORT FUNCTION

E n g i n e e r i n g o f s i t e , b u i l d i n g , and p o o l E n g i n e e r i n g of r e a c t o r , t a n k , and m e c h a n i c a l c o n t r o l s E n g i n e e r i n g of r e a c t o r c o n t r o l s ( e l e c t r i c a l p o r t i o n ) E n g i n e e r i n g of i n s t r u m e n t a t i o n ( m e c h a n i c a l ) E n g i n e e r i n g of i n s t r u m e n t a t i o n ( e l e c t r i c a l ) C o n s t r u c t i o n of r e a c t o r , t a n k , and m e c h a n i c a l c o n t r o l s Construction of r e a c t o r c o n t r o l s ( e l e c t r i c a l p o r t i o n ) C o n s t r u c t i o n of i n s t r u m e n t a t i o n ( m e c h a n i c a l ) C o n s t r u c t i o n of i n s t r u m e n t a t i o n ( e l e c t r i c a l )

TARGET DATE

PER C E N T COMPLETE

3/1/53 3/1/53 7 / 1/5 3 5/1/53 3/ 1/5 3 9/1/53 12/1/53 8/ 1/53 2/ 1/51 3

100 100 20 50 10 0 5 20

5 20

.

P E R I O D ENDING MARCH 1 0 , 1 9 5 3

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Tower S h i e l d i n g F a c i l i t y ( P e r s p e c t i v e ) .

99

A N P PROJECT QUARTERLY PROGRESS REPORT aeJrmffee DWG. C-121188

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100

Tower Shielding Facility (Plan V i e w ) .

PERIOD ENDING MARCH lo,, 1953 8.

NUCLEAR MEASUREMENTS

A fast-neu tron scintillation s p e c t r o m e t e r e m p l o y i n g UF c r y s t a l s , which h a v e l o w gamma-ray r e s p o n s e , i s b e i n g d e v e l o p e d , The 6-Mev Van d e G r a a f f h a s been s e t up i n t h e HighV o l t a g e L a b o r a t o r y , b u t no r e s e a r c h h a s y e t b e e n u n d e r t a k e n i n t h e new location.

FAST-NEUTRON SCINTILLATION SPECTROMETER J . Schenck F. J . M u c k e n t h a l e r Physics Division T h e w o r k on t h e d e v e l o p m e n t o f a s c i n t i l l a t i o n spectrometer for f a s t neutrons has appeared so promising f o r s h i e l d i n g work t h a t two r e s e a r c h p e r s o n n e l have been a s s i g n e d t o t h e p r o j e c t t o a c c e l e r a t e t h e work.

Although europium-activated l i t h i u m

i o d i d e c r y s t a l s have been used t o d a t e , l i t h i u m f l u o r i d e w o u l d b e much more d e s i r a b l e b e c a u s e o f i t s lower gamma-ray r e s p o n s e .

T h e work i s now c o n c e n t r a t e d i n an e f f o r t t o grow a 1i t h i u m f l u o r i d e c r y s t a l w i t h s u i t a b 1 e s c i n t i 11a t i on p r o p e r t i e s

.

MEASUREMENTS WITH THE 6-MEV V A N d e GRAAFF

H. B. W i l l a r d , P h y s i c s D i v i s i o n The 6-Mev Van d e G r a a f f was moved d u r i n g t h e q u a r t e r from i t s t e m p o r a r y l o c a t i o n i n B u i l d i n g 9201-2, Y-12 s i t e , t o i t s permanent q u a r t e r s i n t h e High-Vol t age Labor a t o r y, Bui l d i n g 4 5 0 0 , X-10 s i t e .

A beam w a s f i r s t obtained l a t e i n t h e q u a r t e r , but no cross-section measurements were undertaken

.

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INTRODUCTION AND SUMMARY The r e s e a r c h on f u s e d f l u o r i d e systems (sec. 9 ) h a s been l a r g e l y concerned with t h e development o f t e c h n i q u e s f o r p u r i f y i n g and p r e p a r i n g e n r i c h e d ARE f u e l a n d f u e l c a r r i e r .

T h e f 1u o r i d e t r e a t m e n t p r o c e d u r e involves successive purging of t h e l i q u i d w i t h HF, H , , HF, a n d f i n a l l y He. The t r e a t e d f u e l t h e n c o n t a i n s o n l y t r a c e s o f HF, NiF,, and FeF,, which a r e p r i m a r y f a c t o r s i n f l u o r i d e corrosion.

T h e b e n e f i c i a l e f f e c t on the corrosion of the reducing agents h a s been s u b s t a n t i a t e d , and t h e quantity of the various reductants t h a t may b e t o l e r a t e d i n t h e f u e l h a s been d e f i n e d .

The consequences o f t h e a t t e n d a n t r e d u c t i o n o f some UF, t o UF, a r e b e i n g i n v e s t i g a t e d . F o r t h e longer-range f u e l development p r o g r a m , s e v e r a l t e r n a r y and q u a t e r n a r y f l u o r i d e systems containing LiF a r e b e i n g i n v e s t i g a t e d , a s w e l l a s some binary chloride mixtures containing

uc1,.

The c o r r o s i o n r k s e a r c h ( s e c . 1 0 ) h a s been p r i m a r i l y o n t h e d e t e r m i n a t i o n of the corrosion c h a r a c t e r i s t i c s of fluoride mixtures.

The i n c r e a s e d attack experienced i n recent tests w i t h t h e ARE f u e l m i x t u r e i s b e l i e v e d t o be due t o f a u l t y p u r i f i c a t i o n r a t h e r t h a n t o hand1i n g t e c h n i q u e s .

Zirconium hydride a s an a d d i t i v e t o t h e f u e l mixture reduces t h e fluoride a t t a c k o n I n c o n e l by a f a c t o r o f 2.

Apparently t h e mechanism i s t h e reduction of the m e t a l l i c fluorides N i F , a n d FeF,, w h i c h a r e p r e s e n t i n t h e f u e l , because a d d i t i o n of t h e s e fluorides to the fuel increases the c o r r o s i o n . Measurements o f t h e concent r a t i o n o f N i F , , FeF,, and CrF, a s a f u n c t i o n of exposure time of Inconel i n t h e f u e l h a v e b e e n made a s an index of corrosion.

The n i c k e l content remains approximately c o n s t a n t and t h e i r o n c o n t e n t d r o p s s h a r p l y t o a c o n s t a n t v a l u e ; h o w e v e r , t h e chromium

c o n t e n t r i s e s d u r i n g t h e f i r s t 100 h r and then l e v e l s o f f .

After the a d d i t i o n of ZrH,, t h e only s i g n i f i c a n t c h a n g e i n t h e s e c o n c e n t r a t i o n s was i n t h e chromium c o n t e n t , which t h e n c h a n g e d i n t h e same manner a s t h e i r o n content.

The a d d i t i o n o f chromium m e t a l was n o t e f f e c t i v e i n inhibiting f l u o r i d e c o r r o s i o n , a p p a r e n t l y because o f t h e low s o l u b i l i t y o f chroniium i n the fluoride.

Although I n c o n e l and s t a i n l e s s s t e e l a r e s e v e r e l y a1,tacked by l e a d i n t e s t s i n c o n v e c t i o n l o o p s , molybdenumand columbium a r e r e l a t i v e l y immune.

However, s t a t i c t e s t s o f l e a d - s o d i u m a l l o y s show t h a t s o d i u m a d d i t i o n s d e c r e a s e t h e o t h 13 r w i s e s e v e r e l y c o r r o s i v e a c t i o n of t h e l e a d on b o t h I n c o n e l and s t a i n l e s s s t e e l .

T h e s t a b i l i t y o f Be0 i n NaK i s , s t i l l being investigated.

It appears t h a t t h e r e i s some s o l u b i l i t y o f Be0 i n NaK.

The m e t a l l u r g y and c e r a m i c s r e s e a r c h ( s e c . 11) i n c l u d e s t h e f a b r i c a t i o n o f v a r i o u s r e a c t o r components f o r u s e a t high temperatures; creep r u p t u r e t e s t s o f s t r u c t u r a l m e t a l s ; t h e development o f s p e c i a l a l l o y s , c e r m e t s , and ( c e r a m i c c o a t i n g s ; and t e s t s o f w e l d i n g and brazing a l l o y s . Control o r s a f e t y rod i n s e r t s are being prepared for t h e G-E r e a c t o r a n d f o r t h e Tower S h i e l d i n g Facility.

Chrome-plated, highconductivity f i n s have n o t proved adequate for high-temperature r a d i a t o r use, but Inconel or s t a i n l e s s - s t e e l - c l a d c o p p e r f i n s may now b e s a t i s f a c t o r i l y brazed.

Recent creep tests of s t a i n l e s s s t e e l and I n c o n e l h a v e shown t h a t s u r f a c e o x i d a t i o n i s n o t the c o n t r o l l i n g f a c t o r i n the longer rupture times o b s e r v e d i n a i r a s compared w i t h t h e r u p t u r e times i n hydrogen and argon.

The c o n e - a r c w e l d i n g t e c h n i q u e i s being adapted t o the welding of dished headers â&#x201A;Źor heat exchangers because of t h e unequal a r c d i s t a n c e s encountered.

B e c a u s e o f d i l u t i o n and embrittlement of the Nicrobraz used i n

105

A N P PROJECT QUARTERLY PROGRESS REPORT brazing a h e a t exchanger element o t h e r a l l o y s have been c o n s i d e r e d f o r this application.

The e v a l u a t i o n o f high- temperature a l l o y s with r e s p e c t t o temperature, s t r e n g t h , and c o r r o s i o n resistance is continuing.

The p h y s i c a l p r o p e r t y measurements were made p r i m a r i l y f o r t h e d e t e r m i n a t i o n of various p r o p e r t i e s of s e v e r a l f l u o r i d e m i x t u r e s , and t h e h e a t t r a n s f e r s t u d i e s were c o n c e r n e d with experimental systems, a s w e l l a s a i r c r a f t components ( s e c . 1 2 ) . The h e a t c a p a c i t y o f t h e ARE f u e l w a s f o u n d t o b e 0 . 3 1 c a l / g o o C from 550 t o 850OC. Vapor p r e s s u r e m e a s u r e m e n t s o f t h e e n r i c h e d f u e l m i x t u r e were lower t h a n e x p e c t e d and i n d i c a t e d t h e f o r m a t i o n o f complex i o n s a t high t e m p e r a t u r e s . P r e l i m i n a r y measurements w e r e made o f b o t h t h e t h e r m a l c o n d u c t i v i t y and t h e v i s c o s i t y o f sodium hydroxide a t elevated temperatures.

A minimum-weight a n a l y s i s w a s c o m p l e t e d f o r an a i r c r a f t r a d i a t o r with t h e optimum f i n s p a c i n g a n d t h i c k n e s s and t h e optimum t u b e s p a c i n g and d i a m e t e r .

Experimental apparatus t o determine t h e f l u i d v e l o c i t y p r o f i l e s and t h e f l u i d temperature s t r u c t u r e is being assembled.

One s t u d y i s u n d e r way t o determine temperature d i s t r i b u t i o n i n e n t r a n c e r e g i o n s , whereas another s t u d y w i l l compare t h e v a r i o u s h i g h temperature heat t r a n s f e r f l u i d s .

C r e e p u n d e r i r r a d i a t i o n and c o r r o s i o n by s o d i u m i n a n i n - r e a c t o r l o o p a r e

b e i n g i n v e s t i g a t e d ; however, i r r a d i a t i o n of fluoride mixtures comprises t h e g r e a t e r p a r t o f t h e r a d i a t i o n damage s t u d i e s (sec. 13).

In recent irr a d i a t i o n s o f t h e ARE f u e l m i x t u r e i n t h e MTR, i n which t h e power g e n e r a t i o n i s 20 t i m e s t h a t e x p e c t e d i n t h e ARE, c o r r o s i o n and changes i n t h e f u e l c o m p o s i t i o n o c c u r r e d t h a t were i n excess of those observed i n control tests.

However, t h e I n c o n e l and t h e f u e l were a t t e m p e r a t u r e s i n e x c e s s o f 1500'F d u r i n g t h e t e s t s .

The r e c e n t i n - r e a c t o r c r e e p measurements confirmed previous conclusions t h a t i r r a d i a t i o n h a d l i t t l e e f f e c t on t h e creep strength.

A n a l y t i c a l s t u d i e s of r e a c t o r m a t e r i a l s (sec. 14) included chemical, p e t r o g r a p h i c , and x - r a y d i f f r a c t i o n i d e n t i f i c a t i on o f i m p u r i t i e s , c o r r o s i o n p r o d u c t s , r e d u c t i o n p r o d u c t s , and c o n s t i t u e n t s of r e a c t o r f u e l s .

Volumetric methods f o r t h e d e t e r m i n a t i o n of zirconium i n the presence of u r a n i u m and f o r t h e s i m u l t a n e o u s d e t e r m i n a t i o n o f uranium t r i f 1uori.de and z i r c o n i u m m e t a l h a v e b e e n d e v e l o p e d .

An a p p a r a t u s h a s b e e n b u i l t t o a i d i n t h e determination of t r a c e s of oxides i n fluorides.

With p e t r o g r a p h i c and x - r a y - d i f f r a c t i o n s t u d i e s , it has been p o s s i b l e t o determine and d e f i n e c o m p o s i t i o n s o f t h e compounds and e u t e c t i c s p r e s e n t i n UC14-NaC1, U C l , - K C l , a n d NaF-ZrF,-UF, systems.

A

106

PERIOD ENDING MARCH 9.

lo!,

1953

CHEMISTRYOFHIGH-TEMPERATURE LIQUIDS W. R. G r i m e s ,

Materials Chemistry Division

The m a j o r e f f o r t o f t h e ANP C h e m i s t r y g r o u p c o n t i n u e s t o be d e v o t e d t o t h e study of f l u o r i d e mixtures f o r use a s a i r c r a f t r e a c t o r f u e l s and c o o l a n t s .

A l a r g e f r a c t i o n of t h i s e f f o r t h a s been d e v o t e d t o t h e s p e c i f i c m a t e r i a l s t h a t comprise t h e fuel solvent, the c o n c e n t r a t e d f u e l , and t h e f i n a l f u e l m i x t u r e f o r t h e ARE. The f i n a l p r o c e s s i n g p l a n s f o r preparation of t h e f l u o r i d e mixtures i n pure form are n e a r l y f i n i s h e d .

P r o c e d u r e s f o r removing a l l e x c e p t t r a c e s o f HF, NiF, and FeF, from t h e s e materials a r e i n the final developmen t a l s t a g e s .

Contrary t o previous b e l i e f s , hydrogen d o e s c a u s e p a r t i a l r e d u c t i o n o f UF, t o UF, i n t h e s e m e l t s a t 800째C. The b e n e f i c i a l e f f e c t o f r e d u c i n g a g e n t s on t h e c o r r o s i o n o f f l u o r i d e m i x t u r e s h a s been w e l l sub s t a n t i a t e d , and the q u a n t i t i e s o f v a r i o u s r e d u c t a n t s t h a t may b e t o l e r a t e d i n t h e f u e l s h a s been d e f i n e d .

P h a s e e q u i l i b r i u m and o t h e r s t u d i e s of s y s t e m s i n which a l l o r p a r t o f t h e UF, h a s been r e p l a c e d by UF, a r e s t i l l being carried out a s a p a r t of the s t u d y o f t h e e f f e c t o f added r e d u c i n g a g e n t s and a s a n a i d i n t h e i d e n t i f i c a t i o n of c o r r o s i o n p r o d u c t s .

Addit i o n a l m a t e r i a l s h a v e been s y n t h e s i z e d t h a t c o n t a i n t r i v a l e n t uranium and seem t o b e i d e n t i c a l w i t h s p e c i e s produced d u r i n g c o r r o s i o n .

In the hope o f d e v e l o p i n g Other and s u p e r i o r fuel mixtures f o r future applications, an e x t e n s i v e s t u d y o f p h a s e e q u i l i b r i a i n systems c t a i n i n g l i t h i u m f l u o r i d e i s being c a r r i e d o u t .

Some s t u d y o f UC1, s y s t e m s i s a l s o i n p r o g r e s s .

-

c e n t r a t i o n s of up t o 45 mole % and

ZrF, c o n c e n t r a t i o n s o f u p t o 5 0 m o l e %.

The l o w e s t m e l t i n g p o i n t o l ~ s e r v e d was 440째C f o r t h e m i x t u r e c o n t , a i n i n g 68.5 m o l e % L i F , 2 6 . 5 m o l e % UI:,, a n d 5.0 mole % ZrF,.

T h e r m a l h a l t s were n o t e d w i t h t h i s c o m p o s i t i o n , als w e l l as with o t h e r compositions nearly t h e s a m e , a t a b o u t 400 t o 4 1 5 째 C ; h o w e v e r , i t c a n n o t be a s c e r t a i n e d d e f i n i t e l y from t h e d a t a t h a t h a v e b e e n o b t a i n e d whether t h i s e f f e c t is due t o a e u t e c t i c o f unknown c o m p o s i t i o n o r t o a solid transition.

KF-LiF-BeF,-UF,.

The e f f e c t on t h e m e l t i n g p o i n t o f v a r y i n g t h e UI: c o n ? c e w t r a t i o n o f one c o m p o s i t i o n i n t h e K F - L i F - B e F , -UF, s y s t e m h a :3 b e e n d e t e r m i n e d , T h e d a t a show t h a t when UF, i s a d d e d t o t h e 4 0 % BeF,, 20% KF, a n d 20% L i F m i x t u r e t h e m e l t i n g p o i n t g o e s t h r o u g h a minimum a t a l o w c o n c e n t r a t i o n o f UF, and t h e n r i s e s r a t h e r r a p i d l y w i t h i n c r e a s i n g UF, c o n c e n tration.

The t h e r m a l e f f e c t n o t e d a t 330 t o 340째C may i n d i c a t e t h e e x i s t e n c e of a low-melting-point e u t e c t i c i n t h e four-component system; a g r e a t d e a l o f work w i l l be r e q u i r e d t o determine t h e composition o f the eutectic, The l o w e s t m e l t i n g t e m p e r a t u r e o b s e r v e d t o d a t e i s 38OOC a t 2 . 5 mole % o f UF,.

FUEL MIXTURES CONTAINING ThF,

L. M. B r a t c h e r

C. J . B a r t o n Ma t e r i a 1 s C h e m i s t r y D i v i s i o n

L. M. B r a t c h e r C. J . B a r t o n Materials Chemistry D i v i s i o n

O t h e r i n v e s t i g a t o r s ( ) h a v e shown t h a t t h e LiF-ThF, e q u i l i b r i u m d i a g r a m i s q u i t e s i m i l a r t o t h a t o f t h e LiF-UF, system, and unpublished d a t a o b t a i n e d i n this laboratory indicated that the BeF,-ThF, system i s s i m i l a r t o the BeF,-UF, s y s t e m . S i n c e t h e L i F - B e F , b i n a r y i s common t o b o t h s y s t e m s , i t

LiF-ZrF,-UF,.

T h e L i F - Z r F , -UF, s y s t e m was i n v e s t i g a t e d w i t h UF, c o n -

( l ) J . 0 . B l o m e k e , An I n v e s t i g a t i o n o f ThF,Fused S a l t S o l u t i o n s f o r Homogeneous B r e e d e r R e a c t o r s , O R N L - 1 0 3 0 (June 19, 1951).

FUEL MIXTURES CONTA

107

ANP PROJECT QUARTERLY PROGRESS REPORT a t a p p r o x i m a t e l y 430°C. From t h e limited data obtained with the lower ThF, c o n c e n t r a t i o n s , i t a p p e a r s t h a t compositions i n t h i s system t h a t melt below 400°C w i l l c o n t a i n a l o w conc e n t r a t i o n o f ThF, a n d a h i g h c o n c e n t r a t i o n o f BeF,.

seemed r e a s o n a b l e t o assume t h a t t h e LiF-BeF,-ThF, equilibrium diagram would be c o m p a r a b l e t o t h e d i a g r a m f o r t h e LiF-BeF,-UF4 s y s t e m d e s c r i b e d i n the previous report.(2) The d a t a shown i n F i g . 9 . 1 c o n f i r m t h i s e x pec t a t i o n .

T h e h i g h e r me1 t i n g p o i n t o f t h e L i F - T h F , e u t e c t i c ( 5 5 0 ° C comp a r e d w i t h 490OC f o r L i F - U F , ) i s reflected i n the contours.

A comp o s i t i o n c o n t a i n i n g 5 mole % ThF,, 6 7 m o l e % L i F , a n d 28 m o l e 7% BeF, m e l t s (2)L.

M.

FUEL MIXTURES CONTAINING UC1,

R. J . S h e i l

C. J. B a r t o n Materials Chemistry Division

The p r o b l e m o f o b t a i n i n g p u r e UC1, h a s n o t y e t been c o m p l e t e l y s o l v e d .

Efforts t o prepare the pure material

B r a t c h e r and C. J . B a r t o n , ANP Q u a r .

1 9 5 2 , O W L - 1 4 3 9 , p. 1 0 5 .

Prog. R e p . D e c . 1 0 ,

._

JEGFtrr DWG. (8746

ThF

1114°c

LIF

BeF2

543OC

Li2BeF4

475OC

F i g . 9.1.

108

The System L i F - B e F , - T h F , .

845°C

PERIOD ENDIIYG MARCH 1 0 , 1 9 5 3 by s u b l i m a t i o n from t h e a v a i l a b l e c r u d e UC1, h a v e n o t b e e n s u c c e s s f u l .

S y n t h e s i s o f UC1, b y l i q u i d - p h a s e chlorination with hexachloropropylene(,) h a s been used t o provide m a t e r i a l f o r r e c e n t s t u d i e s . Although a n a l y t i c a l d a t a from which t o e v a l u a t e t h i s material are not yet available, i t appears t h a t the material is not o f good q u a l i t y .

The d a t a r e p o r t e d b r i e f l y below may t h e r e f o r e be r e v i s e d when p u r e r UC1, becomes a v a i l a b l e .

NaC1-UCI,.

Thermal d a t a on 18 comp o s i t i o n s i n t h e NaC1-UC1 s y s t e m h a v e been r e p o r t e d by K r a u s . 4 , ) He conc l u d e d , on t h e b a s i s o f t h e d a t a obtained from c o o l i n g curves, t h a t t h e compound 2NaCl.UC1, was t h e o n l y compound f o r m e d i n t h i s s y s t e m a n d that it me1ted incongruently a t 4 3 0 rt 5 ° C .

I t a l s o appeared from h i s d a t a t h a t t h e r e was o n l y o n e e u t e c t i c , which m e l t e d a t 3 7 0 f 5°C. The p r e s e n t , i n c o m p l e t e i n v e s t i g a t i o n seems t o show t h e e x i s t e n c e o f two e u t e c t i c s a n d t w o compounds i n t h i s s y s t e m . The f i r s t e u t e c t i c is believed t o be a t about 30 m o l e % UCl,, and i t a p p e a r s t o m e l t a t 4 2 0 rt 1 0 ° C .

One o f t h e c o m p o ~ n d s , Na2UC1,, i s b e l i e v e d t o m e l t c o n g r u e n t l y a t 440 10°C. The second e u t e c t i c i s b e l i e v e d to be a t a p p r o x i m a t e l y 4 5 mole % U C l , , a n d i t a p p e a r s t o m e l t a t 37OoC, i n good agreement with Kraus' r e s u l t s .

In t h e 6 5 t o 9 0 m o l e % UC1, r a n g e , a s e r i e s o f b r e a k s a t 420 rt 10°C p r o b a b l y represents the incongruent melting p o i n t o f a c o m p o u n d s u c h a s NaU2C1, o r NaU3C1 3 .

T h e p u r e compound h a s n o t y e t been p r e p a r e d , a n d i t c a n n o t be d e f i n i t e l y i d e n t i f i e d on t h e b a s i s of i n f o r m a t i o n a v a i l a b l e a t t h i s t i m e . rmal d a t a o n 1 4 comKC 4.' p o s i t i o n s i n t h e KC1-UC1, s y s t e m , i n the 20 to 7 e % UC1, r a n g e , h a v e a l s o b e e n r e p o r t e d by K r a u s . ( , ) These

+

( 3 ) B . M . Pitt e t a l . , The P r e p a r a t i o n of T C l , w i t h H e r a c h l o r o p r o p y l e n e , C-2.350.3 ( J u l y 2 7 , 1945). ("C. A. K r a u s , P h a s e D i a g r a m of Some C o m p l e x S a l t s of U r a n i u m w i t h H a l i d e s of t h e A l k a l i and A l k a l i n e E a r t h M e t a l s , M-251 ( J u l y 1, 1943).

d a t a s h o w e d t h a t t h e r e was o n e comp o u n d , K2UC1,, w h i c h m e 1 t e d c o n g r u e n t l y a t 6 5 0 rt 5"C, a n d two e u t e c t i c s i n t h e system.

The KCL-K2UC1, e u t e c t i c w a s s t a t e d t o b e a t 2 5 m o l e % UCll,, a n d i t s m e l t i n g p o i n t w a s g i v e n a s 5 6 0 + 5°C; t h e K2UC1,-UCl, e u t e c t i c was i n d i c a t e d t o be a t 5 3 m o l e % UC1 , a n d i t s m e l t i n g p o i n t was 3 5 0 k 5 04C. Thermal d a t a and p e t r o g r a p h i c examination o f t h e s o l i d p h a s e s show s t r o n g e v i d e n c e f o r t h e e x i s t e n c e o f t h r e e compounds and t h r e e e u t e c t i c s i n t h i s system.

The p r e s e n t r e s u l t s are i n f a i r agreement w i t h t h o s e o f K r a u s on t h e l o c a t i o n and melting p o i n t o f t h e KC1-K2UC1, e u t e c t i c , t h e m e l t i n g p o i n t o f K2UC1,, a n d t h e m e l t i n g p o i n t o f the higher eutectic.

However, i t a p p e a r s t h a t a K2UC1,-KUClS e u t e c t i c w i t h 4 2 . 5 k 2 . 5 m o l e % UC1, o c c u r s i n t h i s system and t h a t i t m e l t s a t 320 k 10°C. T h e c o m p o u n d KUC1, probably melts congruently, but a r e l i a b l e value f o r i t s melting point h a s n o t y e t b e e n o b t a i n e d . The t h e r m a l e v i d e n c e f o r t h e e x i s t e n c e o f a comp o u n d w i t h m o r e t h a n 1 m o l e % UC1, p e r m o l e o f KC1 i s a s e r i e s o f b r e a k s i n t h e 7 0 t o 85 m o l e % UC1, r e g i o n a t 4 0 0 rt 5°C. The t h e r m a l e f f e c t a t t h i s t e m p e r a t u r e may i n d i c a t e t h e i n c o n g r u e n t m e l t i n g p o i n t o f t h i s compound o f unknown c o m p o s i t i o n .

A s mentioned i n t h e s e c t i o n on NaC1-UCl,, a n d i n l i n e w i t h e x p e r i e n c e w i t h f l u o r i d e styst e m s , i t h a s been found r a t h e r d i f f i c u l t t o p r e p a r e i n c o n g r u e n t l y m e 1 t i n g compounds i n s u f f i c i e n t l y pure state t o permit t h e i r p o s i t i v e i d e n t i f i ca t i o n .

The c o m p o s i t i o n o f t h e KUC1, -KUI: C l 4 * + e u t e c t i c h a s n o t been a c c u r a t e l y determined.

FUEL -MIXTURES CONTAINING UF,

C. J . B a r t o n Ma t e r i a l s Ch e m i s t r y D i v i s i on

V. S. Coleman

Work on t h e N a F - U F , a n d KF-UF3 s y s t e m s h a s n o t y e t r e v e a l e d comp o s i t i o n s t h a t melt below 700 a n d 680°C, r e s p e c t i v e l y C o m p l i Ica t i o n s

.

109

A N P PROJECT QUARTERLY PROGRESS REPORT f r o m UO, a n d UF, i n t h e m e l t s h a v e been m i n i m i z e d b y u s i n g a l k a l i f l u o r i d e s t h a t h a v e b e e n t r e a t e d w i t h HF a t h i g h t e m p e r a t u r e s and by m i n i m i z i n g t h e t o p t e m p e r a t u r e t o which t h e m e l t i s heated t o decrease disproportionat i o n o f t h e UF,.

These systems are studied, a t p r e s e n t , i n n i c k e l c a p s u l e s welded under an argon atmosphere.

The e x a m i n a t i o n is hampered b e c a u s e t h e KF-UF, compounds decompose r e a d i l y i n the laboratory air.

Petrographic e x a m i n a t i o n i s a c c o m p l i s h e d by g r i n d i n g t h e m a t e r i a l i n a dry, i n e r t atmosphere and t r a n s f e r r i n g i t t o m i c r o s c o p e s l i d e s under o i l . Although t h e thermal data are as yet inconclusive, i t a p p e a r s t h a t t h e compound f o r m e d i n NaF- b e a r i n g m e 1 t s i s 3NaF-2UF3.

A D D I T I O N O F R E D U C I N G AGENTS TO ARE FUEL

J . D. Redman L. G. O v e r h o l s e r K. J. K e l l y

V. S. Coleman D . C. Hoffman F. F. B l a n k e n s h i p

Materials Chemistry Division Decreased corrosion o f Inconel i n thermal c o n v e c t i o n l o o p s h a s been d e m o n s t r a t e d t o r e s u l t from s m a l l a d d i t i o n s o f NaK, ZrHz, o r Zr" t o f l u o r i d e m i x t u r e s o f i n t e r e s t a s ARE fuels.

When t h e s e r e d u c i n g a g e n t s a r e added i n l a r g e q u a n t i t i e s t o m a t e r i a l s c o n t a i n i n g UF,, t h e y p r o d u c e UF,, w h i c h i s o n l y s p a r i n g l y s o l u b l e i n t h e m e l t a t 600°C. Therefore the r e a c t i o n s o f p o s s i b l e ARE f u e l s w i t h v a r i o u s r e d u c i n g a g e n t s have been studied i n an e f f o r t to discover a s a f e u p p e r l i m i t t o t h e amount o f s u c h a d d i ti v e s .

P r e v i o u s e x p e r i m e n t s had demons t r a t e d t h a t a d d i t i on o f s u f f i c i e n t r e d u c t a n t r e s u l t e d i n s e p a r a t i o n of UF, a s a d i s c r e t e ' p h a s e , w h i c h c o u l d b e r e m o v e d by f i l t r a t i o n a t 6 0 0 ° C .

The r e s u l t i n g f i l t r a t e s r e v e a l e d n o t r a c e o f t h e e a s i l y d e t e c t a b l e UF, a f t e r s o l i d i f i c a t i o n , b u t t h e y showed considerable q u a n t i t i e s of various

110

c o m p l e x c o m p o u n d s o f UF,.

Identical m i x t u r e s ( w i t h t h e same r e d u c i n g a g e n t s ) t h a t were n o t f i l t e r e d showed c o n s i d e r a b l e q u a n t i t i e s o f UF,.

If a sufficiently small quantity of r e d u c i n g a g e n t was added so t h a t n o UF, c o u l d b e f i l t e r e d a t 600"C, t h e r e w a s n o UF, d e t e c t e d i n t h e c o o l , solidified material.

V a r i o u s ZrF4 - b e a r i n g m i x t u r e s , w i t h a n d w i t h o u t a d d e d UF,, h a v e b e e n e q u i l i b r a t e d with predetermined small q u a n t i t i e s o f NaK ( 7 8 w t % K ) , Z r H , , a n d Zr" i n s e a l e d c a p s u l e s o f I n c o n e l by r o c k i n g f o r 16 h r a t 4 cpm w i t h t h e e n d s o f t h e c a p s u l e s a t 800 and 650°C, respectively.

T h e c a p s u l e s were th:n h e a t e d a t 800°C i n a v e r t i c a l p o s i t i o n f o r 2 t o 6 h r to permit s e t t l i n g of insoluble material and, e s p e c i a l l y , unreacted reducing agent.

Cooled s a m p l e s were s e c t i o n e d l o n g i t u d i n a l l y f o r petrographic examination.

The upper t o l e r a n c e l i m i t s i n number o f e q u i v a l e n t s ( o n e e q u i v a l e n t i s t h e q u a n t i t y o f r e d u c t a n t needed t o r e d u c e a l l UF, t o UF,) a r e l i s t e d i n T a b l e 9.1.

R e d u c i n g a g e n t s a d d e d t o NaZrF5 i n a m o u n t s i n e x c e s s o f 0 . 2 w t % showed o p a q u e n o n m a g n e t i c m a s s e s , and c h e m i c a l and x-ray tests i n d i c a t e d t h e m a t e r i a l t o b e , a t l e a s t i n p a r t , Zr".

Appare n t l y , t r i v a l e n t zirconium does n o t e x i s t i n fluoride m e l t s under these circumstances.

Verificationof the tolerance values f o r Z r H , i n t h e ARE f u e l m i x t u r e h a s b e e n o b t a i n e d b y e q u i l i b r a t i o n o f ZrH, with t h e f u e l mixture a t 800°C i n n i c k e l e q u i p m e n t , f o l l o w e d by e q u i l i b r a t i o n a t 600°C a n d f i l t r a t i o n o f t h e r e s u l t i n g m e l t a t 600°C through sintered nickel.

The d a t a o b t a i n e d by chemical a n a l y s i s o f t h e f i l t r a t e and by p e t r o g r a p h i c e x a m i n a t i o n o f t h e f i l t e r e d r e s i d u e a r e shown i n T a b l e 9.2.

The d a t a i n d i c a t e t h a t n o s o l i d material exists in the liquid at 600°C i f l e s s t h a n 0 . 9 w t % Z r H , i s added t o t h e mixture.

Agreement b e t w e e n t h e da:ta s h o w n i s p r o b a b l y

c

c

L

*

.

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 w i t h i n t h e e r r o r of s u c h e x p e r i m e n t s .

T h e f a i l u r e t o o b s e r v e UF,, a s s u c h , i n any o f t h e f i l t r a t e s a f f o r d s conf i r m a t i o n of t h e a s s u m p t i o n s used t o i n t e r p r e t the previous data.

When s m a l l q u a n t i t i e s ( u p t o a b o u t 0.4 eq) of reducing agent a r e added, an olive-drab phase ( a v e r a g e r e f r a c t i v e i n d e x of 1 . 5 5 8 ) o c c u r s i n t h e NaF-ZrF4UF, m i x t u r e s .

R e d u c i n g a g e n t s a d d e d t o compos i t i o n s i n t h e NaF-ZrF,-UF, system p r o d u c e d an o l i v e - d r a b p h a s e ( a v e r a g e

r e f r a c t i v e index of 1.558) a t t h e 0.2-eq concentration.

The q u a n t i t y o f olive-drab phase generally increased u p o n a d d i t i o n o f 0 . 4 e q of r e d u c i n g agent.

With l a r g e r a d d i t i o n s o f reducing agent, a decrease in t h e o l i v e - d r a b p h a s e was o b s e r v e d , , a l o n g w i t h an i n c r e a s e i n t h e r e d - o r a n g e p h a s e (UF3*2ZrF4). S y n t h e s i s and p e t r o g r a p h i c e x a m i n a t i o n have i n d i c a t e d t h a t t h e o l i v e - d r a b p h a s e may b e UF3-2ZrF4, i n w h i c h t e t r a v a l e n t uranium has been p a r t i a l l y s u b s t i t u t e d f o r

AMOUNT TOLERABLE FLUORIDE USED

Zro

ZrH,

NaK L

Equivalent

Weight

%

Equivalent.

Weight

%

Equivalent

Weight

%

NaZrF5 NaF-Zr F, -UF4 ( 4 6 - 5 0 - 4 mole % )

0.6

NaF-ZrF4-UF, (50-46-4 mole %)

0.4

'Hydrogen

0.5

0.8

0.7

1.2

1

1.0

c o n s i d e r e d n e u t r a l i n c a l c u l a t i o n of e q u i v a l e n t w e i g h t .

f

TABLE 9.2. DATA OBTAINED BYCHEMICAL ANALYSIS AND PETROGRAPHIC EXAMINATION OF ARE FUEL* AFTER TREATMENT WITH ZrH,

ZrH,

ADDED

(wt

sa)

URANIUM CONTENT OF FILTRATE (wt

0

8.62

0.2

8.72 8.68

0.5 0.7

Uranium r e d u c t i o n o c c u r r e d ; no d i s c r e t e UF, o b s e r v e d

8.65

0.9 1.0 1.5

6.58 7.12

1.5

8.64

*NaF-ZrF4-UF4

PETROGRAPHIC O B S E R V A T I O N S

%)

UF,

f o u n d on f i l t e r and i n r e a c t i o n chamber

5.95 P r e s e n c e of Z r O z i n d i c a t e d a n oxygen l e a k

( 5 0 - 4 6 - 4 mole Sf.

111

ANP PROJECT QUARTERLY PROGRESS REPORT t r i v a l e n t u r a n i urn.

Petrographic e x a m i n a t i o n s r e v e a l e d t h a t UF,-UF,4ZrF, was an o l i v e - d r a b , p l e o c h r o i c phase, with an average r e f r a c t i v e i n d e x of 1.564, a b i r e f r i n g e n c e of about 0 , 0 0 8 , and an o p t i c a n g l e of 80 d e g r e e s .

Another olive-drab m a t e r i a l ( r e f r a c t i v e index of 1.574) was o b t a i n e d when t h e s e m a t e r i a l s w e r e m i x e d t o c o r r e s p o n d t o UF3-3UF,8ZrF4. A m i x t u r e c o r r e s p o n d i n g t o 3UF3-UF,-8ZrF4 p r o d u c e d s t r i a t e d c r y s t a l s o f o l i v e - d r a b and r e d - o r a n g e materials.

T h e 50 m o l e % NaF c o m p o s i t i o n d e v e l o p e d f r e e UF, u p o n a d d i t i o n o f 1 . 2 e q o f Z r o o r ZrH,.

The 46 mole % NaF c o m p o s i t i o n f o r m e d f r e e UF, u p o n t h e a d d i t i o n of 1 . 6 e q Z r " o r ZrH,.

The u s u a l o l i v e - d r a b a n d o r a n g e - r e d p h a s e s w e r e o b s e r v e d i n t h e s e comp o s i t i o n s with less than 1.2 eq of r e duc t a n t s .

I t was n o t e d t h r o u g h o u t t h i s s t u d y t h a t t h e 46 m o l e % NaF, 5 0 m o l e % ZrF,, 4 m o l e % UF, c o m p o s i t i o n t o l e r a t e d s l i g h t l y more r e d u c t i o n w i t h o u t p r e c i p i t a t i n g UF, t h a n d i d t h e 5 0 m o l e % NaF, 4 6 m o l e % Z r F , , 4 m o l e % UF, c o m p o s i t i o n .

F u r t h e r , i t was n o t e d t h a t b o t h c o m p o s i t i o n s a r e more t o l e r a n t t o Z r " and ZrH, t h a n t o NaK. T h e s e o b s e r v a t i o n s s u p p o r t t h e mechanism s u g g e s t e d p r e v i o u s l y , ( 5 ) which p o s t u l a t e s t h a t NaF a n d UF, c o m p e t e f o r t h e ZrF, p r e s e n t .

The Na(K)F f o r m e d b y t h e NaK r e d u c t i o n r e a c t i o n i s c a p a b l e of b r e a k i n g t h e UF3*2ZrF4 complex t o form Na(K)ZrF5 and f r e e UF,.

On t h e o t h e r h a n d , ZrF, f o r m e d by t h e Z r " o r ZrHz r e d u c t i o n r e a c t i o n i s c a p a b l e o f c o m p l e x i n g m o r e UF,.

T h i s s u g g e s t s t h a t a f l u o r i d e comp o s i t i o n with a ZrF,-to-NaF r a t i o l a r g e r t h a n u n i t y would b e d e s i r a b l e i f only becaust of i t s capacity t o complex UF,. ("F. F . B l a n k e n s h i p , D . C. H o f f m a n , K . J .

K e l l y , a n d T. N. M c V a y , A N P Q u a r . P r o g . R e p .

D e c . 10, 1 9 5 2 , ORNL-1439, p . 1 1 9 .

112

COOLANT DEVELOPMENT

L. M. B r a t c h e r

C. J . B a r t o n M a t e r i a l s Chemistry D i v i s i o n LiF-ZrF,.

Study of t h e LiF-ZrF, system, mentioned i n the previous p r o g r e s s r e p o r t , ( ) h a s been c o n t i n u e d by t h e r m a l a n a l y s i s a n d b y p e t r o g r a p h i c a n d x- r a y - d i f f r a c t i on e x a m i n a t i o n o f s o l i d i f i e d melts.

A l t h o u g h Li,ZrF6 i s t h e o n l y compound t h a t h a s been p o s i t i v e l y i d e n t i f i e d , t h e r e i s some e v i d e n c e f o r o n e a d d i t i o n a l compound w i t h l e s s t h a n 3 3 mole % ZrF, a n d one w i t h more t h a n 50 mole % ZrF,.

CsF-ZrF,.

B o t h Cs,ZrF, a n d CsZrFS have been i d e n t i f i e d by p e t r o g r a p h i c e x a m i n a t i o n o f m e l t s i n t h e CsF-ZrF, s y s t e m , and t h r e e e u t e c t i c s h a v e b e e n shown t o e x i s t .

The l o w e s t - m e l t i n g p o i n t ( 4 1 2 f. 1 0 째 C ) e u t e c t i c c o n t a i n s a b o u t 40 m o l e % ZrF,. F u r t h e r work i s in progress t o complete the equilibrium diagram f o r the system.

KF-L i F Z r F , T h e KF- L i F- Z r F, s y s t e m h a s b e e n e x a m i n e d o v e r a ZrF, c o n c e n t r a t i o n r a n g e o f 5 t o 6 0 m o l e %.

A ternary eutectic melting a t about 3 8 5 째 C a p p e a r s c l o s e t o t h e KF-ZrF, eutectic.

The e x a c t c o m p o s i t i o n of t h i s e u t e c t i c h a s n o t y e t been e s t a b lished.

Me 1t i n g p o i n t d e t e r R b F - L i F - ZrF, m i n a t i o n s h a v e b e e n m a d e f o r comp o s i t i o n s i n t h e RbF-LiF-ZrF, s y s t e m t h a t h a v e 5 t o 60 m o l e % ZrF,.

The r e s u l t s were s i m i l a r t o t h o s e o b t a i n e d w i t h KF-LiF-ZrF, m i x t u r e s . The l o w e s t m e l t i n g p o i n t shown t o d a t e was 370째C f o r a m i x t u r e c o n t a i n i n g 45 mole % RbF, 45 mole % ZrF,, and 1 0 mole % L i F ; t h i s composition i s probably close t o a ternary eutectic.

Thermal e f f e c t s a t a b o u t 550째C were o b s e r v e d w i t h a number of c o m p o s i t i o n s i n t h i s r e g i o n .

These e f f e c t s a r e b e l i e v e d t o b e due t o the presence i n the fused mixture o f c o m p l e x o x y f l u o r i d e s t h a t may r e s u l t from t h e h y g r o s c o p i c n a t u r e of t h e RbF.

-

.

.

-

-

( 6 ) L . M. B r a t c h e r and C. J . B a r t o n , ANP Q u a r .

P r o g . R e p . D e c . I O , 1 9 5 2 , ORNL-1439, p. 1 1 3 .

PERIOD ENDING MARCH 1 0 , 1 9 5 3 KF- L i F - B e F , .

The d a t a o b t a i n e d thus f a r with compositions i n the 4 t o 5 7 m o l e % B e F , r a n g e o f t h e KF-LiF-BeF, system s e e m t o i n d i c a t e t h a t only s l i g h t l o w e r i n g of t h e m e l t i n g p o i n t r e s u l t s f r o m t h e a d d i t i o n o f KF t o LiF-BeF, m i x t u r e s .

The l o w e s t m e l t i n g p o i n t t h a t h a s b e e n c o n f i r m e d by b o t h h e a t i n g and c o o l i n g c u r v e s i s 350째C f o r t h e m i x t u r e w i t h 54 m o l e % B e F 2 , 10 mole % KF, a n d 36 mole % L i F , a n d it is o n l y s l i g h t l y lower t h a n t h e m e l t i n g p o i n t (365OC) o f t h e 50 mole % LiF, 50 mole % BeF, c o m p o s i t i o n .

P R O D U C T I O N AND P U R I F I C A T I O N OF FLUORIDE MIXTURES

F. F. B l a n k e n s h i p

G. J. N e s s l e M a t e r i a l s Chemistry D i v i s i o n H. W. S a v a g e , Ai" D i v i s i o n

Study of t h e h y d r o g e n a t i o n - hydrofluorination procedure previously described(') f o r fuel preparation has b e e n c o n t i n u e d on l a b o r a t o r y and p i l o t scales.

Operating conditions t o p r o v i d e optimum p u r i t y o f t h e m o l t e n m i x t u r e s a r e now r e a s o n a b l y w e l l defined.

C o n s t r u c t i o n of t h e p r o d u c t i o n s c a l e e q u i p m e n t f o r p r o d u c i n g 3000 l b o f ARE f u e l s o l v e n t ( N a Z r F 5 ) h a s b e e n d e l a y e d t o some e x t e n t b y l a c k o f manpower.

T h i s e q u i p m e n t s h o u l d be available f o r t e s t i n g early in April, and t h e m a t e r i a l s h o u l d be p r e p a r e d d u r i n g May and J u n e . A l l raw m a t e r i a l s f o r t h i s o p e r a t i o n have b e e n r e c e i v e d , and c h e m i c a l a n d s p e c t r o g r a p h i c analyses of each b a t c h i n d i c a t e t h a t the m a t e r i a l s a r e of s a t i s f a c t o r y purity.

Laboratory-Scale Fuel Preparation.

(C. M. B l o o d , F. P. Boody, R. E . Thoma, Jr., Materials Chemistry Division).

C o r r o s i o n by s e l e c t i v e r e m o v a l of chromium from I n c o n e l i n f l u o r i d e m e l t s may o c c u r b y a n y c o m b i n a t i o n of s e v e r a l mechanisms.

Three of t h e (7)F.

F. B l a n k e n s h i p and G.

J . N a s s l e . ANP 122.

Quar. P r o g . R e p . D e c . 1 0 . 1 9 5 2 , ORNL-1439. p.

most l i k e l y of t h e s e p r o c e s s e s a r e : Cr" + 3UF, 2Cr" + 3HF

and

CrF, + 3UF3

;

(1)

2CrF, + 3H,

;

(2 1

-d

2Cr" + 3NiF2

3Ni0 + 2CrF,

,

2Cr0 + 3FeF,

3Fe0 + 2CrF,

,

Cr" + FeF,

f--

Feo + CrF,

(3)

.

Addition of the strong reducing agent ZrH, would be e x p e c t e d t o minimize t h e c o r r o s i o n , r e g a r d l e s s of which mechanism was e f f e c t i v e .

C o r r o s i o n by t h e f i r s t mechanism c a n be m i n i m i z e d by r e d u c t i o n o f UF, t o UF, by some r e d u c t a n t s u c h (3s Z r H , to the extent tolerable without excessive deterioration o f t h e physical p r o p e r t i e s of t h e f u e l .

C o r r o , s i o n by t h e o t h e r mechanisms c a n , i n p r i n c i p l e , b e e l i m i n a t e d by t h e p r o p e r t e c h n i q u e s f o r removing t h e r e a g e n t m a t e r i a l s .

The h y d r o g e n a t i o n - h y d r o f l u o r i n a t i o n p r o c e s s f o r f u e l p u r i f i c a t i o n was o r i g i n a l l y c h o s e n a s t h e one most l i k e l y t o produce very pure f l u o r i d e l i q u i d s . The s c h e d u l e f o r t h i s p r o c e s s was p r e s c r i b e d t o p r o v i d e w h a t was c o n s i d e r e d t o be l a r g e e x c e s s e s o f t i m e f o r r e a c t i o n and s t r i p p i n g a t each stage.

In recent experiments, a t t e m p t s w e r e made t o q u a n t i t a t i v e l y evaluate t h e chemical changes d u r i n g each p r o c e s s s t a g e .

The n e e d f o r s u c h d a t a i s obvious.

Incomplete t r e a t m e n t a t any s t a g e is r e f l e c t e d by poor c o r r o s i o n c h a r a c t e rist i c s ; however, long t r e a t m e n t times a r e uneconomical i n terms o f e q u i p m e n t l i f e , p r o d u c t i o n r a t e , m a t e r i a l consumed, a n d manpower r e q u i r e d and, i n a d d i t i o n , r e s u l t i n s l i g h t a l t e r a t i o n i n f u e l composition b e c a u s e o f v o l a t i l i z a t i o n o f t h e ZrF,.

Stripping with i n e r t gas should s e r v e a s a r a p i d a n d r e a s o n a b l y comp l e t e method f o r r e m o v i n g HF, b e c a u s e the acid fluorides are unstable a t t e m p e r a t u r e s a b o v e 500째C. Since any r e s i d u a l HF s h o u l d l e a d t o e n h a n c e d c o r r o s i o n , t h e p r o g r e s s o f HF r e m o v a l

113

A N P PROJECT QUARTERLY PROGRESS REPORT has been s t u d i e d i n t e n s i v e l y by a n a l y z i n g t h e e x i t g a s s t r e a m f o r HF. I n i t i a l experiments revealed t h a t p l o t s o f t h e l o g a r i t h m o f HF c o n c e n t r a t i o n i n t h e h e l i u m v s . volume o f h e l i u m p a s s e d were e s s e n t i a l l y l i n e a r , w i t h h a l f - l i f e v o l u m e s b e t w e e n 40 and 70 l i t e r s when 0 . 5 t o 1 . 2 l i t e r s / m i n o f h e l i u m was p a s s e d t h r o u g h a b o u t 1 l i t e r ( 3 k g ) of t h e m e l t .

From t e s t s o f t h e s t r i p p i n g o f t h e HF by He, i t may b e c o n c l u d e d t h a t t y p i c a l b a t c h e s o f f u e l p r e p a r e d by t h e s t a n d a r d procedure described previously should h a v e b e e n s t r i p p e d t o a b o u t lo', mole o f HF p e r l i t e r o f He and s h o u l d h a v e c o n t a i n e d a b o u t 1 0 ppm o f HF i n t h e m e l t . T h e r e i s no d e t e c t a b l e d i f f e r e n c e i n s t r i p p i n g r a t e w i t h He b e t w e e n t h e NaZrF, a n d t h e NaF-ZrF,-UF, mixture c o n t a i n i n g 4 mole % UF,.

The e f f e c t o f f l o w r a t e on a t t a i n m e n t of e q u i l i b r i u m vapor c o n c e n t r a t i o n h a s been only p a r t l y explored.

When h y d r o g e n i s u s e d t o s w e e p t h e m e l t a f t e r p a s s a g e o f HF, t h e a c i d c o n t e n t of t h e e f f l u e n t g a s i s cons i d e r a b l y h i g h e r t h a n when h e l i u m i s used.

The f o l l o w i n g r e a c t i o n s a r e almost c e r t a i n l y r e s p o n s i b l e : NiF, + H, 2FeF3-+ H, FeF, + H,

ZUF, + H,

+

Ni"

+

+

+

+ 2HF,

AFolooooK =

2FeF, + 2HF,

-65 kcal ,

&olOOO~K

= -31.5 kcal

,

Feo + 2HF, ~ o l o o o ~=K1 . 5 kcal ,

ZUF, + ZHF,

~ o l o o o o K=

22.0 kcal

.

I n t r e a t m e n t of NaZrF, w i t h h y d r o g e n a t 800째C h a l f - l i f e volumes o f a b o u t 70 l i t e r s a r e f o u n d . S i n c e m o s t o f t h e s e experiments are performed i n n i c k e l c o n t a i n e r s , a p p r e c i a b l e amounts t h e HF r e s u l t from r e d u c t i o n o f NiF,.

I n s t r i p p i n g o f t h e ARE f u e l m i x t u r e w i t h H,, t h e c o n t r a s t b e t w e e n H e a n d H, i s e v e n more n o t i c e a b l e .

When H, i s u s e d , t h e HF c o n t e n t o f t h e g a s drops sharply, as expected, but it l e v e l s o f f a t a b o u t l o e 4 m o l e HF p e r l i t e r o f H,.

The r e d u c t i o n of UF, t o UF, i n t h e s o l i d s t a t e i s c o n s i d e r e d n e g l i g i b l e b e l o w 900째C. However, UF, 114

h a s b e e n shown by p e t r o g r a p h i c t e c h n i q u e s t o b e p r e s e n t i n ARE f u e l b a t c h e s a f t e r p r o l o n g e d H, t r e a t m e n t a t 7 0 0 t o 800OC. T h e r e seems t o b e no d o u b t t h a t t h e h i g h v a l u e s f o r HF i n t h e e x i t g a s a r e a c o n s e q u e n c e of t h i s reaction.

From t h e r a t e o f HF e v o l u t i o n , i t a p p e a r s t h a t t h e r a t e o f r e d u c t i o n i s a b o u t 3% o f t h e UF, p r e s e n t p e r hour.

F i l t r a t i o n of the m e l t a f t e r h y d r o g e n t r e a t m e n t a n d HF s t r i p p i n g serves t o reduce the nickel content of t h e f u e l b a t c h t o l e s s t h a n 150 ppm.

I t h a s n o t been p o s s i b l e , t o d a t e , t o b r i n g t h e i r o n c o n t e n t of It t h e m e l t t o s u c h a low l e v e l . a p p e a r s , however, t h a t l o w v a l u e s f o r N i F , , F e F , , a n d HF c a n b e a c h i e v e d w i t h o u t e x c e s s i v e e x p o s u r e t i m e s and w i t h o u t undue r e d u c t i o n of t h e UF,.

P i l o t - S c a l e Fuel P u r i f i c a t i o n (G. J . N e s s l e , J . E. E o r g a n , M a t e r i a l s Chemistry Division).

During the p a s t q u a r t e r , a t o t a l o f 3 2 6 . 4 kg of mixed f l u o r i d e s , c o m p r i s i n g 24 s m a l l b a t c h e s o f a p p r o x i m a t e l y 2 k g e a c h and 11 l a r g e b a t c h e s of a p p r o x i m a t e l y 25 kg e a c h , h a s been p r o c e s s e d by t h e group i n B u i l d i n g 9928 and d i s p e n s e d t o req u e s t i n g p e r s o n n e l i n t h e ANP D i v i s i o n .

H e a t i n g t h e c o n t r o l p a n e l s t o 125째F h a s r e s u l t e d i n marked i m p r o v e m e n t i n t h e smoothness and e f f i c i e n c y of operation.

The a d d i t i o n of t w o p r e s s u r e g a g e s , o n e d i r e c t l y on t h e r e a c t o r c a n and one d i r e c t l y on t h e receiver can, has eliminated the difficulty in discovering possible d a n g e r p o i n t s , and minor f a i l u r e s d u r i n g a r u n a r e now p r a c t i c a l l y nonexistent.

The p r o c e s s f o r t r e a t m e n t o f mixed f l u o r i d e s h a s been modified t o p e r m i t 1 . 5 h r o f s t r i p p i n g w i t h H, and 1 . 5 h r o f s t r i p p i n g w i t h He a f t e r t h e HF t r e a t m e n t and b e f o r e t r a n s f e r o f t h e molten f l u o r i d e s .

A g a s t h r o u g h p u t of about 15 l i t e r s / m i n i s a c c o m p l i s h e d by p r e s s u r i z i n g t o 1 0 l b ( g a g e ) a n d r e l e a s i n g t o 0 l b ( g a g e ) 30 t i m e s p e r hour.

T h e HF c o n t e n t o f t h e s t r i p

* d

PERIOD ENDING MARCH 1 0 , 1 9 5 3 g a s i s u s u a l l y a b o u t lo', mole/liter a t t h e time of f u e l t r a n s f e r .

This p r o b a b l y c o r r e s p o n d s t o a b o u t 1 0 ppm o f HF i n t h e m e l t .

The c o m b i n a t i o n o f H, t r e a t m e n t and f i l t r a t i o n t h r o u g h sintered nickel has reducedthesoluble n i c k e l i n t h e m e l t f r o m 900 t o l e s s t h a n 150 ppm.

F l u o r i d e P r o d u c t i o n F a c i l i t y ( G . J. Nessle, M a t e r i a l s C h e m i s t r y D i v i s i o n ; H. W . S a v a g e , ANP D i v i s i o n ) . T h e production f a c i l i t y for preparing i n e x c e s s of 3000 l b of f u e l s o l v e n t i s scheduled for completion during the month o f March.

Shakedown r u n s and o t h e r p r e l i m i n a r y t e s t s of t h e a p p a r a tus should require less than four weeks; t h e p r o d u c t i o n o p e r a t i o n c o u l d , i f n e c e s s a r y , b e f i n i s h e d by m i d - J u n e .

The l o w - h a f n i u m ZrC1, h a s b e e n conv e r t e d t o ZrF,, and t h e e q u i p m e n t f o r t h i s p r o c e s s h a s b e e n c l e a n e d and p u t into standby condition for future use, i f needed.

At present, the s t o c k p i l e c o n t a i n s 3000 l b of ZrF,.

A l l b a t c h e s o f t h e ZrF, h a v e b e e n s a m p l e d a n d a n a l y z e d by c h e m i c a l methods f o r z i r c o n i u m and f l u o r i n e .

Complete s p e c t r o g r a p h i c a n a l y s e s , w i t h s p e c i a l s h o t s of e a c h b a t c h , f o r h a f n i u m and b o r o n a r e a v a i l a b l e .

The b o r o n c o n t e n t o f t h e b a t c h e s r a n g e s f r o m 1 . 8 t o 0 . 3 ppm, w i t h a n a v e r a g e o f 0 . 8 ppm, a n d s e v e n o f t h e n i n e b a t c h e s s h o w l e s s t h a n 8 5 ppm hafnium.

The o t h e r two b a t c h e s , c o m p r i s i n g a b o u t 25% of t h e t o t a l , show 150 and 550 ppm hafnium.

A b o u t 1 0 0 0 l b o f NaF f r o m o n e p r o d u c t i o n l o t h a s been s t o c k p i l e d for u s e i n f u e l p r o d u c t i o n .

Chemical and s p e c t r o g r a p h i c e x a m i n a t i o n s o f s a m p l e s from t h r e e c o n t a i n e r s i n d i c a t e that the material is satisfactory for use.

Hydrof l u o r i n a t i o n o f Zr0,-NaP M i x t u r e s ( R . E . T h o m a , J r . , C . M. B l o o d , Ma t e r i a 1 s C h e m i s t r y D i v i s i o n ) T h e f e a s i b i l i t y o f p r o d u c i n g NaZrFs by a s h o r t t r e a t m e n t o f N a F - Z r O , m i x t u r e w i t h HF a t a h i g h tempi-= r a t u r e h a s been d e m o n s t r a t e d .

Best r e s u l t s a r e o b t a i n e d when some p r e v i o u s l y p r e p a r e d NaZrFS i s added t o t h e c h a r g e so t h a t a l i q u i d phase is present An amount during the i n i t i a l stages. o f NaZrFS t h a t i s e q u i v a l e n t t o 10% o f t h e t o t a l charge appears t o be s u f f i c i e n t t o b r i n g about complete conv e r s i o n of t h e m i x t u r e i n 4 h r a t 800째C. U t i l i z a t i o n o f a b o u t 30% o f t h e HF d e l i v e r e d h a s b e e n a t t a i n e d .

T h e r e a r e s t i l l some p r o b l e m s i n c o n n e c t i o n w i t h t h e equipment f o r t h i s operation.

Frequent rupture of the HF i n p u t l i n e o c c u r r e d when n i c k e l t u b i n g was u s e d .

Metallographic examination revealed t h a t the a t t a c k was d u e t o s u l f u r , w h i c h w a s p r o b a b l y p r e s e n t i n t h e ZrO, f e e d .

Graphite l i n e r s i n t h e n i c k e l r e a c t o r s have been used s a t i s f a c t o r i l y ; however, t h e r e h a s been d i f f i c u l t y i n t h e use o f g r a p h i t e d i p l i n e s f o r HF I l e c a u s e of breakage d u r i n g runs.

F u r t h e r s t u d y of t h i s procedure, which promises t o reduce m a t e r i a l l y t h e c o s t o f ZrF, a s NaZrFS, i s p l a n n e d .

.

115

J

1

e, L

10.

CORROSION RESEARCH

W. D. Manly, M e t a l l u r g y D i v i s i o n W. R. G r i m e s , M a t e r i a l s C h e m i s t r y D i v i s i o n H . W. S a v a g e , ANP D i v i s i o n

C o r r o s i o n phenomena a r e u s u a l l y examined f i r s t i n s t a t i c or seesaw t e s t s , and t h e n s e l e c t e d s y s t e m s o r phenomena a r e examined i n t h e c o n v e c t i o n loops.

C r e v i c e c o r r o s i o n , e f f e c t of e x p o s u r e t i m e , and t h e e f f e c t s o f a d d i t i v e s have been s t u d i e d i n both s t a t i c and d y n a m i c t e s t s d u r i n g t h e p a s t q u a r t e r . No s i g n i f i c a n t i n c r e a s e i n c o r r o s i o n was n o t e d i n s t a t i c t e s t s . However, t h e c r e v i c e c o r r o s i o n found i n thermal convection loops was a b o u t t h r e e t i m e s t h a t f o u n d i n a d j a c e n t t u b i n g ; t h e m e c h a n i s m by which c r e v i c e s i n c r e a s e c o r r o s i o n i s n o t y e t understood.

Corrosion, as e v i d e n c e d by t h e chromium m e t a l c o n t e n t o f t h e f l u o r i d e , h a s b e e n shown t o b e f a i r l y c o n s t a n t a f t e r t h e f i r s t 100 h r o f exposure.

Convection loops t h a t were r u n f o r 1000 h r a t 1500째F i n d i c a t e d t h a t t h e amount o f c o r r o s i o n d e c r e a s e d w i t h t i m e , a l t h o u g h t h e r e was a s m a l l i n c r e a s e i n t h e d e p t h and i n t e n s i t y of attack.

The work on t h e d y n a m i c t e s t i n g o f t h e f l u o r i d e f u e l s i n Inconel thermal c o n v e c t i o n loops h a s c o n t i n u e d , w i t h a m a j o r e f f o r t b e i n g made t o d e t e r m i n e why t h e c o r r o s i o n i n t h e I n c o n e l f l u o r i d e systems h a s been i n c r e a s i n g .

I t h a s b e e n shown t h a t n e i t h e r t h e increase i n fluoride batch size nor poor handling techniques during f i l l i n g were r e s p o n s i b l e ; r e t r e a t i n g t h e f u e l batches has produced c o n t r a dictory results.

Evidence i n d i c a t e s that the increase i n corrosion is b e i n g c a u s e d by f a u l t y p u r i f i c a t i o n , s i n c e t h e c o r r o s i o n was d e e p e r i n loops i n which hydrofluorinated f l u o r i d e m i x t u r e s were c i r c u l a t e d t h a n i t was i n t h e l o o p s t h a t u s e d as-melted f l u o r i d e a s t h e fuel.

One I n c o n e l t h e r m a l c o n v e c t i o n l o o p was

operated with a h o t - l e g temperature of 1 6 5 0 " F , and n o l a r g e i n c r e a s e i n t h e d e p t h o f a t t a c k was n o t e d i n c o m p a r i s o n w i t h t h a t f o u n d i n l o o p s :run a t 1500째F. A whirligig rig, patterned a f t e r o n e d e v e l o p e d b y NACA, w i t h which f l u o r i d e f l o w v e l o c i t i e s o f 10 f p s c a n b e o b t a i n e d , h a s been placed i n operation.

Preliminary t e s t s with t h i s apparatus with f l u o r i d e f u e l s i n I n c o n e l show o n l y a s l i g h t i n c r e a s e i n c o r r o s i v e a t t a c k compared with t h a t found i n s t a t i c capsule tests.

I t was c o n f i r m e d t h a t ZrH, i s a n e f f e c t i v e c o r r o s i o n i n h i b i t o r when u s e d w i t h NaF-ZrF4-UF4 ( 4 6 - 5 0 - 4 m o l e % ) ; TiH, w i l l a l s o i n h i b i t c o r r o s i o n , b u t n o t q u i t e s o e f f e c t i v e l y a s ZrH2.

I t now a p p e a r s t h a t t h e s o l u b i l i t y o f chromium i n NaF-KF-LiF-UF4 ( 1 0 . 9 - 4 3 . 5 4 4 . 5 - 1 . 1 m o l e % ) i s a b o u t 3 0 0 0 ppm, which i s n o t so h i g h a s o r i g i n a l l y expected.

C o n s i d e r a b l e a t t a c k was f o u n d i n an I n c o n e l l o o p i n w h i c h t h e f l u o r i d e had been s a t u r a t e d with chromium m e t a l p r i o r t o c i r c u l a t i o n .

T h e c o m p a t i b i l i t y o f Be0 i n NaK c o n t i n u e s t o b e e x a m i n e d , and a c o r r e l a t i o n between t h e d e n s i t y o f t h e Be0 a n d t h e c o r r o s i o n b e h a v i o r i s being studied.

Various surface t r e a t m e n t s f o r t h e Be0 a r e b e i n g evaluated.

T h e r e i s some e v i d e n c e t h a t B e 0 i s s o l u b l e i n NaK t o a n e x t e n t t h a t i s dependent on t h e temperature of the system.

The c o r r o s i o n o f two c e r m e t s was e x a m i n e d i n both f l u o r i d e s and l i q u i d m e t a l s .

Although t h e t e s t s i n l i q u i d m e t a l s showed l i t t l e o r n o a t t a c k , a t l e a s t one f l u o r i d e t e s t r e s u l t e d i n s i g n i f i cant corrosion.

The m a s s - t r a n s f e r c h a r a c t e r i s t i c s of various metals i n high-purity l e a d a r e b e i n g s t u d i e d by u s i n g

117

ANP PROJECT QUARTERLY PROGRESS REPORT quartz thermal convection loops.

T h e r e s u l t s show t h a t b o t h c o l u m b i u m and molybdenum h a v e v e r y good r e s i s t a n c e t o m a s s t r a n s f e r and c o r r o s i o n i n liquid lead.

On t h e o t h e r h a n d , s e v e r e c o r r o s i o n and mass t r a n s f e r were f o u n d i n l e a d - I n c o n e l s y s t e m s , even t h o u g h t h e l e a d h a d b e e n c a r e f u l l y deoxidized.

M a t e r i a l s t o be t e s t e d i n l i q u i d l e a d i n c l u d e t y p e 304, h i g h and low c a r b o n , s t a i n l e s s s t e e l s , t y p e 410 s t a i n l e s s s t e e l , a n d Armco iron.

T e s t s o f s t a i n l e s s s t e e l and Inconel i n sodium-lead a l l o y s continue t o show t h a t a d d i t i o n s o f s o d i u m t o lead decrease the severe corrosive action.

The e f f e c t o f a h y d r o g e n a t m o s p h e r e i n m i n i m i z i n g mass t r a n s f e r o f n i c k e l i n s o d i u m h y d r o x i d e was d e m o n s t r a t e d by u s i n g a 50-50 m i x t u r e o f h e l i u m and hydrogen.

However, t h e u s e o f a t m o s p h e r e s o f CO,, forming gas, w e t hydrogen, o r d r y a i r under a hydrogen pressure of one-half atmospheric p r e s s u r e r e s u l t e d i n c o n s i d e r a b l e mass transfer.

A number o f s i m p l e and complex f l u o r i d e s of t h e s t r u c t u r a l m e t a l h a s been p r e p a r e d f o r s t u d i e s o f t h e i r e f f e c t on c o r r o s i o n by f l u o r i d e mixtures.

The complex f l u o r i d e s formedin corrosion t e s t s a r e i d e n t i f i e d by e i t h e r p e t r o g r a p h i c o r x - r a y d i f f r a c t i o n techniques,or both.

The o x i d a t i o n o f m o l t e n NaUF, y i e l d e d n o UO,F,, UO,, o r UF,.

However, i t i s e v i d e n t from t h e r e s u l t i n g p r o d u c t s t h a t t h e c o n t a i n e r p l a y s an i m p o r t a n t p a r t i n t h e mechanism o f a i r o x i d a t i o n o f uranium i n t h e molten f l u o r i d e s .

FLUORIDE CORROSIONOF METALS IN STATIC, SEESAW, AND ROTATING TESTS

D. C. V r e e l a n d E. E. Hoffman

J . E. P o p e L. R. T r o t t e r

Metallurgy Division

F. K e r t e s z H. J. B u t t r a m

C. R. C r o f t R. E. Meadows

M a t e r i a l s Chemistry Division Crevice Corrosion.

In connection with the crevice corrosion tests

118

being run, it w a s suggested t h a t a more r e a l i s t i c method o f t e s t i n g would employ a t a p e r e d o r V-shaped c r e v i c e i n t h e bottom o f t h e t e s t i n g tube.

Accordingly, a j i g w a s designed f o r putting tapered crimps i n test tubing.

With t h i s j i g , c r e v i c e s c a n b e made t h a t a r e a p p r o x i m a t e l y 1 1 / 4 i n . l o n g and v a r y i n w i d t h up t o approximately 0. 3 inch.

Several s t a t i c tests with various materials f o r c o n t a i n i n g t h e N a F - Z r F, UF, (46-50-4 mole X) have been run t o test the crevices.

Corrosion i n the c r e v i c e s s e e m e d t o b e somewhat e r r a t i c , w i t h some s u r f a c e s b e i n g a p p a r e n t l y u n a t t a c k e d and o t h e r s h a v i n g t h e usual subsurface voids.

However, accelerated corrosionin these crevices was n o t n o t e d ; t h e a t t a c k t h a t was f o u n d i n t h e c r e v i c e s was n o t beyond what m i g h t b e e x p e c t e d f o r t h e m a t e r i a l s tested.

High-Temperature P r e t r e a t m e n t o f Inconel.

On t h e b a s i s o f r e s u l t s f r o m some p r e v i o u s t e s t s w i t h NaF-KFLiF-UF, ( 1 0 . 9 - 4 3 . 5 - 4 4 . 5 - 1 . 1 m o l e %) a t h i g h t e m p e r a t u r e s ( 1 2 0 0 t o 13OO0C), i t was r e p o r t e d t h a t t h e r e was no surface l a y e r a t t a c k on Inconel.

It w a s thought t h a t perhaps a pret r e a t m e n t a t h i g h t e m p e r a t u r e would r e n d e r I n c o n e l immune f r o m c o r r o s i o n a t t h e u s u a l t e m p e r a t u r e o f 816OC. A c c o r d i n g l y , t w o I n c o n e l t u b e s were loaded with t h e f l u o r i d e , heated f o r 4 h r a t 125OoC, a n d t h e n h e a t e d f o r 2 5 0 h r a t 816OC. Light attack was n o t e d i n each t u b e i n t h e form o f subsurface voids t h a t extended t o a d e p t h o f 1 m i l i n o n e t u b e and 0 . 5 m i l i n the o t h e r tube.

E f f e c t o f Time o f E x p o s u r e o f I n c o n e l t o F l u o r i d e Mixture w i t h and W i t h o u t ZrH, Added.

When t h e A R E f u e l m i x t u r e NaF-ZrF,-UF, (50-46-4 mole X ) , w i t h o u t added m a t e r i a l , i s t e s t e d i n Inconel under an atmosphere o f h e l i u m , t h e s e v e r i t y o f a t t a c k and t h e d e p t h o f p e n e t r a t i o n seem t o i n c r e a s e very s l i g h t l y with exposure t i m e s o f between 100 and 250 h o u r s .

D i f f e r e n c e s between c o r r o s i o n o b s e r v e d

-

I

.

.

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 a f t e r 25 and 100 h r seem t o b e r e a l ,

A p l o t of t h e s t r u c t u r a l metal content of the fluoride mixture vs. exposure t i m e i s s h o w n i n F i g . 1 0 . 1.

It is o b v i o u s t h a t t h e chromium c o n t e n t s h o w s a r a p i d i n i t i a l r i s e and t h e n tends t o level off a t a high value, whereas t h e i r o n c o n t e n t f a l l s r a p i d l y a t f i r s t and t h e n v e r y s l o w l y .

It seems c e r t a i n t h a t r e a c t i o n s s u c h a s

FeF3

-t

Cr

-

CrF3

-t

Fe,

with consequent deposition o f t h e m e t a l l i c i r o n on t h e w a l l s , are r e s p o n s i b l e f o r a p a r t of t h e c o r r o s i o n observed

.

When

t h i s

fuel mixture, with added, w a s t e s t e d i n I n c o n e l , t h e c o r r o s i o n o b t a i n e d was considerably less severe, but t h e c o r r o s i o n changes with exposure time

0.5 w t % ZrH,

were s i m i l a r .

F i g u r e 1 0 . 2 shows t h e r e s u l t s of analysis of the fuel mixture f o r the s t r u c t u r a l metals.

I n t h i s c a s e , FeF, a n d NiF, c o n t e n t s d r o p p e d t o v e r y low v a l u e s b e c a u s e o f the strong reducing agent, and, a p p a r e n t l y , m o s t o f t h e CrF, was a l s o r e d u c e d . However, w i t h i n c r e a s e d e x p o s u r e t i m e , t h e CrF, c o n c e n t r a t i o n increased slightly.

These r e s u l t s a r e encouraging i n t h a t they i n d i c a t e t h a t t h e r e l a t i v e l y large corrosion rates initially observed are d r a s t i c a l l y reduced a t l o n g e r e x p o s u r e times.

S t r u c t u r a l Metal F l u o r i d e A d d l i t i v e s .

Chemical a n a l y s e s o f f l u o r i d e m a t e r i a l s b e f o r e and a f t e r c o r r o s i o n t e s t i n g i n Inconel have repeatedly demonstrated t h a t t h e i r o n and n i c k e l c o n t e n t s o f t h e m i x t u r e a r e r e d u c e d and t h e

1600

1400

f

1200

0 1

t 2

E

1000

z

s

J

5W

800

z -1

a a 3 600 t 0 3

a t v)

400

200

0

Fig. 10.1.

S t r u c t u r a l Metal C o n t e n t o f NaF-ZrF,-UF, F u n c t i o n of Exposure Time.

( 5 0 - 4 6 - 4 mole %) A s

119

ANP PROJECT QUARTERLY PROGRESS REPORT

.

0

100

200 300 EXPOSURE TIME ( h r )

Fig. 10.2. Structural Metal Content NaF-ZrF,-UF4 wt % ZrH,, As a Function of E x p o s u r e T i m e . chromium c o n t e n t i s i n c r e a s e d . reactions 3FeF, -t 2Cr and 3NiF, -t 2Cr

-

+2CrF, 2CrF,

-t

The

3Fe

-t 3Ni

a r e obviously involved i n the corrosion mechanism.

Since both i r o n and n i c k e l f l u o r i d e s a r e l i k e l y t o be p r e s e n t t o some e x t e n t i n t h e f i n a l ARE f u e l a n d s i n c e c o n s i d e r a b l e a m o u n t s o f t h e s e compounds h a v e b e e n p r e s e n t i n some o f t h e b a t c h e s t e s t e d , a s e r i e s of experiments h a s been conducted t o demonstrate t h e e f f e c t s o f t h e f l u o r i d e s o f i r o n , chromium, and n i c k e l i n c o n s i d e r a b l e a m o u n t s on t h e c o r r o s i o n o f I n c o n e l by t h e ARE f u e l and t h e ARE f u e l s o l v e n t .

A d d i t i o n o f e i t h e r F e F , o r NiF, i n c r e a s e s t h e s e v e r i t y o f a t t a c k and depth of penetration.

The a d d i t i o n o f CrF, a p p a r e n t l y h a s n o e f f e c t on the corrosion rate.

When i r o n o r chromium f l u o r i d e s a r e a d d e d , m e t a l l o graphic examination r e v e a l s m e t a l l i c d e p o s i t s on t h e c a p s u l e w a l l s .

Chemical a n a l y s e s o f t h e s o l i d i f i e d melts, a f t e r exposure, reveal t h a t t h e

120

400

500

(50-46-4 mole %),

with 0.5

a d d i t i o n o f CrF, d o e s n o t a p p r e c i a b l y a l t e r t h e amounts o f i r o n and n i c k e l normally found i n t h e mixture.

The a d d i t i o n o f NiF,, h o w e v e r , g r e a t l y i n c r e a s e s t h e amount o f CrF, f o u n d i n the melt; the very large quantities of s o l u b l e n i c k e l added a r e n e a r l y c o m p l e t e l y r e d u c e d and a r e a p p a r e n t l y d e p o s i t e d on t h e w a l l s o f t h e c a p s u l e s o t h a t t h e y a r e n o t removed w i t h t h e f l u o r i d e mass.

T h e a d d i t i o n o f FeF, a l s o s e r v e s t o r a i s e t h e chromium c o n t e n t of the f l u o r i d e mixture, b u t o n l y a p a r t of t h e FeF, seems t o be reduced t o metal.

The h a n d l i n g , s a m p l i n g , and a n a l y t i c a l techniquesare not sufficiently precise t o permit obtaining accurate m a t e r i a l b a l a n c e s from t h e e q u a t i o n s shown a b o v e ; i n g e n e r a l , h o w e v e r , t h e b a l a n c e i s w i t h i n +20%, from w h i c h i t appears t h a t a con2iderable f r a c t i o n o f t h e c o r r o s i o n i s , a s was e x p e c t e d , due t o other actions.

Hydrogen Fluoride Additive. Hydrof l u o r i c a c i d i s one of t h e r e a g e n t s used i n t h e p r o c e s s f o r p u r i f y i n g the fluoride melts.

This reagent may b e p r e s e n t i n t h e m e l t s a t l o w

-

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 concentrations, even though cons i d e r a b l e c a r e is used i n t h e s t r i p p i n g o p e r a t i on S t u d y o f c o r r o s i o n o f I n c o n e l by a b a t c h o f ARE f u e l , N a F - Z r F 4 - U F , ( 5 0 - 4 6 - 4 m o l e % ) , t o w h i c h HF h a d b e e n a d d e d a s NaHF,, showed t h a t heavy subsurface void formation r e s u l t e d when a s much a s 0 . 3 w t % HF w a s present.

T h i s a t t a c k w a s shown t o b e a s much a s 3 m i l s d e e p , w h i c h is a t l e a s t twice the depth expected without addition.

However, t h e u s e o f 0 . 1 w t % HF r e s u l t e d i n l e s s s e v e r e attack, with penetration t o only 1 . 5 m i l s , and t h e a d d i t i o n o f 0 . 0 4 w t % HF y i e l d e d a l i g h t m e t a l l i c d e p o s i t and r e l a t i t v e l y l i g h t c o r r o s i v e a t t a c k .

The f u e l m i x t u r e u s e d i n t h e s e e x p e r i m e n t s h a d b e e n t r e a t e d w i t h H, and, presumably, contained small a m o u n t s o f UF,.

It i s p o s s i b l e t h a t t h e r e a c t i t on I

2UF,,

A

i-2HF ’ \

Chemical a n a l y s i s of t h e f l u o r i d e a f t e r the test revealed the presence o f 0.025% F e , 0.003% N i , a n d 0. 141% C r .

Other tests a r e being run with various additions t o the fluoride mixtures, a n d a t t e m p t s a r e b e i n g made t o v a r y t h e h e a t i n g a r r a n g e m e n t s on t h e t u b i n g s o that sizeable temperature gradients c a n be a t t a i n e d .

S t a t i c Tests on I n c o l o y and I n c o n e l i n Fluorides.

I n c o l o y ( 3 2 % Ni-21% Cr-47% Fe ) w a s t e s t e d i n NaF-ZrF, -UF, ( 4 6 - 5 0 - 4 mole %) f o r 1 0 0 h r a t 816OC. I n a few p l a c e s , s u b s u r f a c e v o i d s t o a depth of 2 m i l s could be noted.

A photomicrograph of t h e Incoloy, t a k e n a f t e r t e s t i n g , i s shown i n F i g . 10.3.

The d e s c a l i n g p r o p e r t i e s o f t h e f l u o r i d e on o x i d i z e d I n c o n e l were t e s t e d a t 816OC, and i t was f o u n d t h a t t h e o x i d i z e d I n c o n e l was c l e a n e d v e r y w e l l a t t h e 1-, 4 - , and 8 - h r t e s t t i m e s t h a t were t r i e d .

2UF, -t H ,

may h a v e m a s k e d t h e d e l e t e r i o u s e f f e c t o f s m a l l HF a d d i t i o n s .

Fluoride Corrosion i n a Rotating Rig. The w h i r l i g i g r i g ( ’ ) i s now r u n n i n g and o p e r a t i o n a l “ b u g s ” a r e g r a d u a l l y b e i n g worked o u t .

In this device i t w i l l be p o s s i b l e t o run relatively high -velocity corrosion tests with t h e fluoride mixtures c o n t a i n e d i n I n c o n e l and o t h e r s u i t a b l e tubing. ,4t t h e p r e s e n t t i m e , a f l u i d v e l o c i t y of approximately 10 f p s i s b e i n g employed.

Upon m e t a l l o g r a p h i c examination a f t e r a 100-hr test with NaF-ZrF,-UF, (46-50-4 mole %) i n I n c o n e l a t a t e m p e r a t u r e o f 816OC (no apprec ia b l e therm a 1 g r a d i en t employed), i t was n o t e d t h a t t h e a t t a c k w a s n o more s e v e r e t h a n t h a t o f t e n encountered i n o r d i n a r y s t a t i c corrosion tests.

The a t t a c k was q u i t e u n i f o r m and was i n t h e f o r m o f subsurface v o i d s t o a depth of 2 m i l s . ( l ) L . C. Desmon and D. R. M o s h e r , P r e l i m i n a r y S t u d y o f C i r c u l a t i o n i n an A p p a r a t u s S u i t a b l e f o r D e t e r m i n i n g C o r r o s i v e E f f e c t s of Hot F l o w i n g L i q u t d s , NACA-RM-E-51D12 (June 2 9 , 1 9 5 1 ) .

FLUORIDE CORROSION OF METALS I N THERMAL CONVECTION LOOPS

G. M. Adamson, M e t a l l u r g y D i v i s i o n E f f e c t o f Fluoride Batch S i z e .

As discussed i n the previous report, ( 2, t h e c o r r o s i o n h a s been i n c r e a s i n g i n t h e I n c o n e l l o o p s c i r c u l a t i n g NaFZrF,-UF, ( 4 6 - 5 0 - 4 mole %).

The increases i n themselves w e r e n o t enough t o c a u s e t r o u b l e , b u t t h e y a r e d a n g e r o u s when r e g a r d e d a s a t r e n d ‘that i s n o t understood.

Consequently, a s e r i e s o f l o o p s was r u n t o d e t e r m i n e whether t h e i n c r e a s e i n batch s i z e i n the production of t h e f l u o r i d e mixture was r e s p o n s i b l e f o r t h e c o r r o s i o n i n c r e a s e . Loops were r u n w i t h f l u o r i d e m i x t u r e s p r e p a r e d i n 5- and 5 0 - l b b a t c h e s for 100- and 500-hr p e r i o d s .

I n both t h e 1 0 0 - and 5 0 0 - h r t e s t s , more c o r r o s i o n was c a u s e d by t h e s m a l l b a t c h e s t h a n by t h e l a r g e b a t c h e s .

Obviously, the increase in batch s i z e was n o t t h e r e a s o n f o r t h e (2)C. M. Adamson, ANP Q u a r . P r o g . R e p . D e e . I O .

1 9 5 2 , ORNL-1439, p . 1 3 3 f f .

12 1

ANP PROJECT QUARTERLY PROGRESS REPORT

I

Fig. 10.3. hr at 816OC.

Static Test of Incoloy in NaF-ZrF4-UF, (46-50-4 mole %) f o r 100

increase in attack.

Furthermore, e v e n t h o u g h e x t r e m e c a r e was t a k e n during f i l l i n g of the loop, the a t t a c k was s t i l l e x t e n s i v e ; t h e r e f o r e poor handling during f i l l i n g w a s a l s o e l i m i n a t e d a s t h e cause.

Fluoride Pretreatment. Two s m a l l b a t c h e s o f NaF-ZrF,-UF, (46-50-4 m o l e 7%) w e r e t a k e n â&#x201A;Ź r o m t h e 5 0 - l b b a t c h and g i v e n a c o m p l e t e r e t r e a t ment.(3) When t h e s e b a t c h e s w e r e circulated i n Inconel loops, the a t t a c k i n one i n s t a n c e was c o n s i d e r a b l y g r e a t e r than average, whereas i n t h e o t h e r i t was l e s s ; t h e r e f o r e i t may b e c o n c l u d e d t h a t some m a j o r v a r i a b l e s t i l l h a s n o t been c o n t r o l l e d . ( 3 ) C . M. B l o o d , A. J . W e i n b e r g e r , F. P. Boody, and G . J. N e s s l e , ANP Q u a r . P r o g . R e p . J u n e 1 0 , 1 9 5 2 , OWL-1294, p. 9 7 .

122

The a t t a c k f o u n d i n I n c o n e l l o o p s i n which NaF-ZrF,-UF, ( 4 6 - 5 0 - 4 mole %) c i r c u l a t e d w a s much l e s s t h a n h a d b e e n f o u n d when NaF-KF-LiF-UF, ( 1 0 . 9 43.5-44.5-1. l m o l e % ) was t h e c i r c u l a t e d m a t e r i a l . (,) S i n c e t h e NaF-ZrF4-UF, had r e c e i v e d more e x t e n s i v e p r e t r e a t m e n t w i t h H, a n d HF, i t s h i g h e r purity is a logical explanation for i t s lower c o r r o s i v e n e s s .

Accordingly, two s p e c i a 1 b a t c h e s o f t h e NaF-KF-LiFUF, m i x t u r e w e r e g i v e n t h e s a m e special pretreatment.

These batches p r o d u c e d a t t a c k o n I n c o n e l t h a t was almost twice t h a t h e r e t o f o r e observed.

Two a d d i t i o n a l b a t c h e s o f t h e s a m e f l u o r i d e were t h e n s p e c i a l l y p r e p a r e d and c i r c u l a t e d i n I n c o n e l l o o p s , and ( 4 ) G . M. Adamson, ANP Q u a r . P r o g . R e p . S e p t . 1 0 , 1 9 5 2 , ORNL-1375, p. 103 f f .

PERIOD ENDING MARCH 1 0 , 1 9 5 3 t h e a t t a c k was even worse than i n the f i r s t test.

In a l l t h e tests with pretreated fuel, the operator reported a strong odor of hydrogen f l u o r i d e d u r i n g t h e f i l l i n g o f t h e loops.

S i n c e hydrogen f l u o r i d e , a s an a d d i t i v e i n s t a t i c t e s t s , h a s b e e n shown t o i n c r e a s e c o r r o s i o n , i t i s most probable t h a t t h e HF u s e d a t o n e s t e p i n t h e f u e l pretreatment, as w e l l a s t h e NiF produced d u r i n g t h i s treatment, is n o t b e i n g c o m p l e t e l y removed and i s causing the increased corrosion.

T h e s e t e s t s show t h a t p o o r p u r i f i c a t i o n may do more harm t h a n good.

Hydride Additives.

It h a s been confirmed t h a t zirconium hydride w i l l r e d u c e t h e a t t a c k o f NaF-ZrF,-UF, ( 4 6 - 5 0 - 4 mole %) on I n c o n e l .

An a d d i t i o n o f 1/2% z i r c o n i u m h y d r i d e i n one t h e r m a l c o n v e c t i o n l o o p r e d u c e d t h e d e p t h o f a t t a c k t o b e t w e e n 1 and 4 mils.

This a t t a c k is lower than normal b u t i s deeper than t h a t found when z i r c o n i u m h y d r i d e i s a d d e d t o NaF-KF-LiF-UF4 ( 1 0 . 9-43. 5 - 4 4 . 5 - 1 . 1 mole %).

The c o o l a n t underwent considerable transformation, as e v i d e n c e d by t h e p r e s e n c e o f a brown m a t e r i a 1.

T i t a n i u m h y d r i d e ( 1 / 2 % ) was a d d e d t o t h e NaF-KF-LiF-UF4 m i x t u r e and circulated i n Inconel.

T h e maximum penetration of 2.5 m i l s , although m u c h l e s s t h a n t h a t f o u n d when n o a d d i t i v e was u s e d , w a s n o t q u i t e s o l o w a s t h a t o b t a i n e d when z i r c o n i u m h y d r i d e was a d d e d .

Surface layers were f o u n d i n b o t h t h e h o t a n d c o l d legs.

T h e s e l a y e r s must r e c e i v e a d d i t i o n a l s t u d y i f any h y d r i d e i s t o be usefd a s an i n h i b i t o r .

M e t a l Additives.

The t h r e e m o s t common i m p u r i t i e s f o u n d i n t h e f u e l a r e n i c k e l , i r o n , a n d chromium.

One l o o p i n which chromium metal powder h a d b e e n a d d e d t o NaF-KF-LiF-UF, (10.9-43.5-44.5-1.1 mole % ) w a s discussecl i n t h e previous r e p o r t . ( 2 ) T h i s t e s t was r e p e a t e d , a n d a g a i n n o change i n t h e average depth of a t t a c k

was f o u n d , n o u n u s u a l l a y e r s were f o u n d , and t h e chromium c o n t e n t o f t h e f l u o r i d e s f r o m t h e l o o p was n o r m a l ; s o a g a i n t h e chromium m e t a l d i d n o t go i n t o solution.

Chromium m e t a l powder, i n s u f f i c i e n t q u a n t i t y t o make 0 . 5 % i n t h e s o l u t i o n , was t h e n a d d e d t o a transfer pot before the fluorides were p l a c e d i n t o i t .

After the f l u o r i d e s h a d b e e n a d d e d , t h e p o t was k e p t h o t and h e l i u m w a s blown t h r o u g h i t f o r 30 m i n u t e s .

Again, average a t t a c k was f o u n d a f t e r t h i s m a t e r i a l had been c i r c u l a t e d i n an Inconel loop.

The chemical a n a l y s i s o f t h i s f l u o r i d e showed a chromium c o n c e n t r a t i o n o f 2 5 0 0 ppm, w h i c h i s a b o u t twice t h e normal c o n c e n t r a t i o n .

F u r t h e r work i s s c h e d u l e d t o d e t e r m i n e w h e t h e r t h e s o l u b i l i t y o f chromium i s much l o w e r t h a n w a s e x p e c t e d .

Th.is i s l i k e l y , s i n c e t h e chromium c o n t e n t did not increase greatly during c i r c u l a t i o n and y e t a t t a c k had t a k e n place.

As a n o t h e r a p p r o a c h t o t h i s p r o b l e m , a s e c t i o n o f I n c o n e l p i p e was chromium p l a t e d and welded i n t o t h e h o t l e g of a loop.

A f t e r t h e NaF-KF-LiF-UF, m i x t u r e had been c i r c u l a t e d , t h e d e p t h of a t t a c k was t h e same i n a d j a c e n t p l a t e d and u n p l a t e d s e c t i o n s .

No t r a c e s o f t h e chromium p l a t e r e m a i n e d on t h e w a l l s .

A metallic appearing l a y e r w a s f o u n d in t h e c o l d leg.

The chromium c o n t e n t of t h e f l u o r i d e s v a r i e d f r o m 2500 t o 3 0 0 0 ppm, w h i c h , a l t h o u g h h i g h e r t h a n n o r m a l , is a b o u t t h e same a s t h a t f o u n d i n t h e l o o p d i s c u s s e d above.

T e m p e r a t u r e Dependence.

A loop f i l l e d w i t h t h e f l u o r i d e f u e l , NaFZrF,-UF, ( 5 0 - 4 6 - 4 m o l e % ) , was o p e r a t e d f o r 5 0 0 h r w i t h a minimum c o l d - l e g t e m p e r a t u r e o f 1500'F a n d a h o t - l e g t e m p e r a t u r e o f 1650'F. The h o t - l e g a t t a c k was m o d e r a t e t o l i g h t , w i t h a m a x i m u m d e p t h o f 11 m i l s a n d a n average depth of 8 m i l s .

A concent r a t i o n o f v o i d s i n the grain boundaries had taken place.

T h e r e s u l t s may b e compared w i t h t h o s e o f a similar

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.

l o o p t e s t i n which t h e h o t - l e g t e m p e r a t u r e was 1500'F. The h o t - l e g a t t a c k i n t h i s l o o p was f r o m 3 t o 10 m i l s deep.

C o m p a r i s o n o f t h e s e two l o o p s i n d i c a t e s t h a t t h e c o r r o s i o n mechanism i s not extremely temperature s e n s i t i v e .

One d i s t u r b i n g f a c t i s t h a t w i t h t h e h o t t e r l o o p t h e r e was some e v i d e n c e o f uranium s e g r e g a t i o n i n t h e c o l d l e g .

T h i s i s now b e i n g c h e c k e d i n a n o t h e r loop.

Crevice Corrosion.

Another loop operated in the study of crevice c o r r o s i o n ( 2 ) was an I n c o n e l l o o p , w i t h two c r e v i c e s b u i l t i n t o t h e h o t l e g , i n w h i c h NaF-ZrF4-UF, ( 4 6 - 5 0 - 4 m o l e %) was c i r c u l a t e d .

The upper h o t - l e g s e c t i o n s h o w e d a maximum a t t a c k o f 16 m i l s a n d a n a v e r a g e a t t a c k o f 12 m i l s , whereas t h e a t t a c k i n t h e lower h o t - l e g s e c t i o n had a maximum d e p t h o f 9 m i l s .

The maximum a t t a c k i n t h e c r e v i c e s was 1 9 m i l s and t h e average was 1 2 m i l s .

The intensity of attack i n the crevice was s e v e r a l times t h a t i n t h e s t r a i g h t section.

This confirms previously obtained r e s u l t s i n t h a t the attack i n the crevice is only slightly deeper but t h e intensity of a t t a c k is g r e a t l y increased.

I n s e r t e d C o r r o s i o n Samples.

Metallographic data received for the p r e v i o u s l y d i s c u s s e d ( 2 , l o o p s i n which t h e r m o c o u p l e t u b e s were i n s e r t e d i n t o t h e c e n t e r o f t h e h o t and t h e c o l d l e g s confirm t h e r e s u l t s obtained with f l a t samples.

W i t h b o t h NaFZrF,-UF, a n d NaF-KF-LiF-UF4, t h e a t t a c k on t h e l o o p w a l l s i n t h e h o t l e g was normal, b u t t h e h o t - l e g i n s e r t s were a t t a c k e d t o a d e p t h o f only 1m i l ; n o s a t i s f a c t o r y explanation h a s b e e n o f f e r e d f o r t h i s phenomenon.

E f f e c t o f Exposure Time.

An I n c o n e l l o o p was u s e d t o c i r c u l a t e NaF-ZrF4-UF, ( 5 0 - 4 6 - 4 mole %) 1000 h r , a n d t h e r e s u l t i n g h o t - l e g a t t a c k was m o d e r a t e t o heavy i n i n t e n s i t y and e x t e n d e d t o d e p t h s o f 5 t o 11 m i l s .

The a t t a c k was p r e s e n t b o t h a s g e n e r a l a t t a c k and a s a c o n c e n t r a t i o n o f t h e

124

voids i n the grain boundaries.

For comparative purposes, t h e s e d a t a a r e s u m m a r i z e d i n T a b l e 10. 1, a l o n g w i t h similar data for loops previously o p e r a t e d f o r 100 and 500 hours.

Although t h e d e p t h and i n t e n s i t y o f t h e a t t a c k i n c r e a s e s with t h e exposure time, t h e r a t e of a t t a c k d e f i n i t e l y decreases.

TABLE 1 0 . 1 . EFFECT OF EXPOSURE TIME ON DYNAMIC CORROSION OF INCONEL BY NaF-ZrF,-UF,

o

~ (hr)

I

MAXIMUM ~ ATTACK ~ (mils)

~ CORROSION IN~TENS1 TY ~ L i g h t t o moderate Light t o moderate Moderate t o h e a v y

Nonu r an ium Bearing Mixtures. S i n c e NaF-ZrF4 ( 5 0 - 5 0 m o l e %) w i l l b e u s e d during the i n i t i a l testing of the ARE, s e v e r a l l o o p s h a v e b e e n o p e r a t e d t o study its effects.

These a r e standard loops, that is, Inconel l o o p s o p e r a t e d f o r 500 h r w i t h a h o t - l e g t e m p e r a t u r e o f 1500'F. The upper s e c t i o n o f t h e h o t l e g of one l o o p showed l i g h t a t t a c k t h a t e x t e n d e d t o depths of 4 t o 8 m i l s , whereas t h e l o w e r s e c t i o n was p r a c t i c a l l y unattacked.

The s e c o n d l o o p i s s t i l l operating.

A t h i r d l o o p , i n which NaF-ZrF, ( 5 2 - 4 8 mole %) was c i r c u l a t e d , yielded scattered intergranular attack o f from 3 t o 8 m i l s i n t h e t o p s e c t i o n of the hot leg.

The lower s e c t i o n showed g e n e r a l p i t t i n g 1 m i l d e e p , w i t h an o c c a s i o n a l p a t c h o f p i t s u p t o 6 m i l s d e e p . No d e p o s i t was f o u n d i n the cold leg.

Z i r c o n i u m h y d r i d e ( 1 / 2 % ) was a d d e d t o anoth.er b a t c h of t h i s c o o l a n t , which was t h e n s u b j e c t t o t h e s t a n d a r d loop t e s t .

The h o t - l e g s u r f a c e o f t h i s l o o p was p i t t e d , b u t t h e a t t a c k , a s s h o w n by t h e s u b s u r f a c e v o i d s , e x t e n d e d t o a maximum d e p t h o f o n l y

N

PERIOD ENDING MARCH 10, 1953

I

b

1.5 m i l s .

A two-phase l a y e r 1 m i l t h i c k was p r e s e n t o n t h e h o t - l e g s u r f a c e , and a t i g h t l y a d h e r i n g metallic-appearing layer 0. 1 m i l t h i c k was f o u n d i n t h e c o l d l e g .

Again t h e zirconium h y d r i d e a c t e d a s an inhibitor, but hot-leg deposits were formed.

One I n c o n e l l o o p c i r c u l a t e d 500 h r The w i t h NaF-BeF, ( 5 7 - 4 3 m o l e % ) . maximum h o t - l e g a t t a c k was 9 m i l s a n d t h e a v e r a g e was 4 m i l s .

More v o i d s were c o n c e n t r a t e d i n t h e g r a i n boundar i e s t h a n a r e n o r m a l l y f o u n d , and t h e voids were larger.

A nonmetallic d e p o s i t was f o u n d i n t h e c o l d l e g .

With b o t h NaF-ZrF4 a n d NaF-BeF2, t h e a t t a c k m e c h a n i s m seems t o b e t h e same as f o r t h e o t h e r f l u o r i d e s . '

L I Q U I D METAL CORROSION OF STRUCTURAL METALS

G . P. S m i t h J . V. C a t h c a r t D. C. V r e e l a n d

E. E. Hoffman L. R. T r o t t e r J . E. P o p e

Metallurgy Division

Seesaw Tests o f Sodium-Lead A l l o y s .

A s e r i e s of seesaw t e s t s o f sodiuml e a d mixtures h a s been run i n I n c o n e l and t y p e s 430 a n d 3 0 4 s t a i n l e s s s t e e l t u b i n g f o r 100 hours.

The l e a d f o r t h e s e t e s t s w a s p u r i f i e d by b u b b l i n g h y d r o g e n t h r o u g h m o l t e n l e a d a t 750째C f o r 1 1/2 h o u r s .

A l l Inconel tubes w e r e a t t a c k e d i n t h e h o t zone. S e v e r i t y of t h e attack decreased with increasing s o d i u m a d d i t i o n s , b u t t h e a t t a c k was s t i l l a p p r e c i a b l e w i t h a 3 0 w t 7% sodium a d d i t i o n , a s shown i n F i g . 10.4,

T

F i g . 1 0 . 4 . Inconel After a Seesaw Test i n a 30 w t % Na-70 w t % P b Mixture f o r 100 hr a t 85OoC. 1OOX.

12 5

ANP PROJECT QUARTERLY PROGRESS REPORT w h i c h i l l u s t r a t e s t h e t y p e and e x t e n t o f a t t a c k of t h e s e s o d i u m - l e a d m i x t u r e s .

I n no c a s e was a t t a c k or d e p o s i t i o n o f c r y s t a l s n o t e d i n t h e c o l d zone upon m e t a l l o g r a p h i c e x a m i n a t i o n ; however , i n several of the tubes, c r y s t a l s couldbe detected i n the bath material.

I n t h e t e s t w i t h t h e t y p e 430 s t a i n l e s s s t e e l t u b i n g , t h e r e was v e r y l i t t l e c o r r o s i v e a t t a c k by t h e sodiumlead mixtures.

Type 304 s t a i n l e s s s t e e l showed e x c e p t i o n a l l y good r e s i s t a n c e t o t h e s e c o r r od a n t s .

A s e c t i o n of t h e h o t zone of a t u b e a f t e r e x p o s u r e t o 5% N a - 9 5 % P b i s shown i n F i g . 1 0 . 5 .

T h e r e was e s s e n t i a l l y no a t t a c k i n any of t h e t e s t s with type 304 s t a i n l e s s s t e e l .

A summary o f t h e s e t e s t s i s g i v e n i n T a b l e 10.2.

S t a t i c Tests with Lithium.

Twocomponent s t a t i c t e s t s o f s e v e r a l m a t e r i a l s have been run with l i t h i u m a t 1000째C t o f u r n i s h a b a s i s of comparison with three-component t e s t s run previously.

S e v e r e a t t a c k had been noted i n t h e three-component t e s t s , 10 t o 15 m i l s p e n e t r a t i o n b e i n g q u i t e common.

It should be emphasized, however, t h a t t h e more r e c e n t t e s t s w e r e s t a t i c t e s t s and t h e a t t a c k m i g h t be l e s s s e v e r e t h a n i n t h e dynamic systems.

Results of t h e s e t e s t s a r e p r e s e n t e d i n T a b l e 10.3.

I n c o l o y i n Sodium, L i t h i u m , and Lead.

I n c o l o y ( 3 2 % N i - 2 1 % Cr-47% F e ) w a s t e s t e d f o r 1 0 0 h r a t 816OC i n s o d i u m , l i t h i u m , and l e a d .

No a t t a c k was n o t e d i n e i t h e r sodium or l i t h i u m , a l t h o u g h some c r y s t a l d e p o s i t i o n was

F i g . 1 0 . 5 . Type 304 S t a i n l e s s S t e e l After a s e e s a w Test i n a 5 w t % Na-95 w t % Pb Mixture f o r 100 h r a t 830OC. 1 O O X .

126

PERIOD ENDING MARCH 1 0 , 1953

SEESAW TESTS OF VARIOUS MATERIALS RUN IN SODIUM-LEAD MIXTURES FOR 100 HOURS

TABLE 10.2.

BATH COMPOSITION

Inconel

1

AVERAGE

'ERATURE

(

( %)

M ATERI AL

METALLOGRAPHIC NOTES

Na

Pb

5 1 d Zone

Hot Zone

5

95

530

8 20

l e r m i n a t e d a f t e r 18 h r , no c i r c u l a t i o n ; 12 m i l s of i n t e r g r a n u l a r a t t a c k in h o t zone

10

90

330

870

h t e r g r a n u l a r a t t a c k e n t i r e l y through 35-mil w a l l i n h o t zone

15

85

3 15

8 60

15 m i l s o f h e a v y i n t e r g r a n u l a r a t t a c k

20

80

39 5

855

12 m i l s o f i n t e r g r a n u l a r a t t a c k i n h o t

25

75

47 0

8 50

i m i l s of intergranular attack i n hot

30

70

48 5

8 50

i mils o f i n t e r g r a n u l a r a t t a c k i n h a t zone

5

95

560

8 30

h s e n t i a l l y no a t t a c k i n e i t h e r h o t o r c o l d zone i n any o f t h e t y p e 304 s t a i n less s t e e l t e s t s

10

90

57 5

8 40

15

85

545

8 30

20

80

58 5

8 25

25

75

600

835

30

70

600

835

5

95

565

8 50

10

90

580

845

15

85

57 5

8 20

20

80

57 5

8 10

25

75

550

805

30

70

6 10

835

i n h o t zone zone zone

Type 304 s t a i n l e s s steel

.

Type 430 stainless stee

E s s e n t i a l l y no a t t a c k in e i t h e r h o t o r c o l d zone i n any o f t h e t y p e 430 s t a i n l e s s steel tests

127

ANP PROJECT QUARTERLY PROGRESS REPORT TABLE 10.3.

RESULTS OF TWO-COIPONENT STATIC TESTS WITH LITEIUM AT 100O'C

__

MATERIAL

TIME OF TEST

Type 316 s t a i n l e s s s t e e l

100

No s i g n o f a t t a c k on s e c t i o n s exposed t o l i q u i d phase; 2 . 5 m i l s o f i n t e r g r a n u l a r a t t a c k on s e c t i o n s exposed t o vapor phase

Inconel

loa

Some m a s s - t r a n s f e r c r y s t a l s c o u l d be n o t e d on the s u r f a c e ; no a t t a c k i n vapor zone; 3 t o 4 m i l s o f s u b s u r f a c e v o i d s on tube i n bath zone

Type 304 s t a i n l e s s s t e e l

400

1 t o 2 m i l s o f i n t e r g r a n u l a r p e n e t r a t i o n and transformation from a u s t e n i t e t o f e r r i t e

METALLOGRAPHIC NOTES

(hr)

apparent i n the t e s t with lithium.

I n the t e s t with lead, 1 t o 2 m i l s of i n t e r g r a n u l a r p e n e t r a t i o n could be noted.

Corrosion by Lead in Thermal Convection LOOPS. A s e r i e s o f t e s t s h a s b e e n made t o d e t e r m i n e t h e e x t e n t o f mass t r a n s f e r and c o r r o s i o n i n t h e r m a l c o n v e c t i on 1o op s c o n t a i n i n g l i q u i d l e a d . The s y s t e m s l e a d - I n c o n e l , l e a d - n i o b i u m , and lead-molybdenum have been s t u d i e d .

Results are also a v a i l a b l e f o r t h e lead-type 304 s t a i n l e s s s t e e l system, but are incomplete.

Since the r e s u l t s of previous i n v e s t i g a t i o n s o f mass t r a n s f e r and corrosion i n lead thermal convection loops have been s u b j e c t t o c r i t i c i s m b e c a u s e o f o x i d e i n t h e l e a d o r on the metal tubing, i n the present series of experiments, t h e l i q u i d l e a d was d e o x i d i z e d w i t h hydrogen p r i o r t o contact with t h e test metal.

C a r e was a l s o t a k e n t o a v o i d heavy o x i d a t i o n o f t h e metal s e c t i o n s o f t h e loops.

The a p p a r a t u s and e x p e r i m e n t a l p r o c e d u r e were d e s c r i b e d i n t h e p r e v i o u s r e p o r t . ('1 The q u a r t z t u b i n g used i n t h e loop is v i r t u a l l y insoluble i n l e a d a t t h e t e s t t e m p e r a t u r e s ; t h e concent r a t i o n o f SiO, i n t h e lead a f t e r one t5)ANP Q u a r . P r o g . R e p . D e c . 1 0 , 1 9 5 2 , ORNL1439, p. 148.

128

t e s t was o n l y 1 7 ppm, a n d t h e S i O , c o n c e n t r a t i o n i n a l e a d sample t h a t had n o t been i n c o n t a c t w i t h g l a s s o r q u a r t z w a s 15 ppm.

Loop t e s t s were r u n w i t h I n c o n e l , columbium, molybdenum and t y p e 304 s t a i n l e s s s t e e l samples suspended i n the c i r c u l a t i n g lead.

The r e s u l t s f o r Inconel have been r e p o r t e d p r e v i ~ u s l y ; ( ~t h) e r e s u l t s f o r t h e o t h e r m e t a l s a r e summarized i n T a b l e 10.4.

The columbium s p e c i m e n s e x h i b i t e d n o mass t r a n s f e r and v i r t u a l l y n o c o r r o s i o n e v e n a f t e r a l m o s t 600 h r of loop operation.

The s m a l l d e c r e a s e i n w a l l t h i c k n e s s was p r o b a b l y d u e t o t h e s o l u t i o n o f t h e s m a l l amount o f c olumbium r e q u i r ed t o s a t u r a t e t h e lead.

No m a s s t r a n s f e r o c c u r r e d w i t h molybdenum, b u t t h e c o r r o s i o n , a l t h o u g h s l i g h t , was a l i t t l e g r e a t e r t h a n t h a t f o u n d f o r columbium.

L i t t l e or n o i n t e r g r a n u l a r p e n e t r a t i o n was observed.

The r e a s o n f o r t h e d i s crepancy i n t h e w a l l - t h i c k n e s s measurem e n t s f o r t h e second lead-molybdenum t e s t i s n o t known.

The molybdenum s p e c i m e n s u s e d w e r e not actually sections of tubing but were made o f molybdenum f o i l b e n t i n t o a cylinder.

The f o i l had a s p e c i f i e d t h i c k n e s s o f 10 m i l s , which was c h e c k e d by m i c r o m e t e r r e a d i n g s a t two p o i n t s on t h e f o i l . I t i s p o s s i b l e t h a t t h e r e was a v a r i a t i o n i n t h i c k n e s s i n t h e

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 TABLE 10.4.

C O R R O S I O N OF S T R U C T U R A L METALS BY L E A D I N QUARTZ THERMAL

TEST

METAL

No’

Columbium

Mo 1ybd enum

Type 304, high carbon, s t a i n l e s s st e e l ( d )

TEMPERATURE (OC) Hot Zone

SPECIMW WALL THICKNESS ( i n . )

Cold Zone. Original

Hot Zone

Cold Zone

1

800

57 5

0.035

0.032

0.034

2

800

56 5

0.035

0.033

0.033

1

800

450

0.010

0.006(‘)

0.006(

2

800

595

0.010

0.011

0.010

1

800

500

TIME OF OPERATION (hr)

(O)Stoppage c a u s e d by f a i l u r e o f h o t l e g h e a t e r ; no p l u g formed. (

Se hedu 1 e d t erai n a t i o n .

(‘)Discrepancy

p r o b a b l y c a u s e d by v a r i a t i o n i n t u b e t h i c k n e s s .

(d)Examinat ion i n c o m p l e t e .

f o i l and t h a t t h e o r i g i n a l f o i l u s e d i n t e s t No. 2 w a s s l i g h t l y g r e a t e r t h a n 10 m i l s t h i c k .

The r e s u l t s o f t h e t e s t w i t h t y p e 3 0 4 s t a i n l e s s steel a r e incomplete.

On t h e b a s i s o f t h e t h e r m a l r e c o r d o f t h e e x p e r i m e n t , however, i t a p p e a r e d t h a t c i r c u l a t i o n i n t h i s l o o p was a l s o s t o p p e d by p l u g f o r m a t i o n .

The t y p e 304 s t a i n l e s s s t e e l specimen used had a c a r b o n c o n c e n t r a t i o n of

C O R R O S I O N O F C E R A M I C S BY F L U O R I D E S AND L I Q U I D M E T A L S

D. C. V r e e l a n d E. E. Hoffman

L. R. T r o t t e r J. E. P o p e Me t a 1l u r gy D i v i s i on E. E. K e t c h e n L. G. O v e r h o l s e r M a t e r i a l s Chemistry D i v i s i o n

L. A. Mann J. M. D. R. Ward

Ci’ s a r

ANP D i v i s i o n

0.087%.

I n summary, b o t h columbium and molybdenum showed v e r y good r e s i s t a n c e t o mass t r a n s f e r and c o r r o s i o n i n l i q u i d Lead.

On t h e o t h e r h a n d , s e v e r e c o r r o s i o n and mass t r a n s f e r occurred i n t h e lead-Inconel systems d e s p i t e t h e c a r e f u l deoxidation of t h e l e a d with hydrogen.

The t e s t s have included a nickel-base a l l o y ( I n c o n e l ) , columbium, molybdenum, and a n i r o n - b a s e a l l o y ( t y p e 304 s t a i n l e s s steel). ‘[t i s p l a n n e d t o e x t e n d t h e s t u d y t o o t h e r i r o n - b a s e a l l o y s , such a s t y p e 410 s t a i n l e s s s t e e l , t o a low-carbon t y p e 304 s t a i n l e s s s t e e l , and t o Armco i r o n . ‘

Cermets i n F l u o r i d e s a n d L i q u i d Two cermets were p r e p a r e d by t h e Ceramics L a b o r a t o r y ; one c o n s i s t e d o f T i c p l u s 20% N i a n d 15% CbC p l u s TaC, a n d t h e o t h e r c o n s i s t e d o f Z r C p l u s 20% i r o n .

T h e s e c e r m e t s were t e s t e d i v v a r i o u s c o r r o s i v e mediums by s e a l i n g t h e m , t o g e t h e r w i t h t h e c o r r o d i n g a g e n t , u n d e r vacuum i n Inconel tubes.

A f t e r t h e t u b e s had b e e n h e a t e d f o r 1 0 0 h r a t 816OC, s p e c i m e n s were r e m o v e d , c h e c k e d f o r w e i g h t and d i m e n s i o n a l c h a n g e s , and examined m e t a l l o g r a p h i c a l l y .

In the t e s t s w i t h s o d i u m a n d l e a d , t h e r e was l i t t l e or n o a t t a c k ( F i g . 1 0 . 6 ) .

The Metals.

129

ANP PROJECT QUARTERLY PROGRESS REPORT

Fig. 10.7. Titanium Carbide Cermet After Exposure to NaF-ZrF,-UF, mole 5%) f o r 100 hr at 816OC.

(46-50-4

TABLE 10.5. RESULTS OF STATIC TESTS OF Tic AND ZrC CERMETS IN SODIUM, LEAD, AND SOME FLUORIDE MIXTURES CERMET T iC

-0.0065

No a t t a c k a p p a r e n t

Pb

Pb a d h e r i n g t o specimen

No a t t a c k a p p a r e n t

NaF-ZrFq-UF4 ( 4 6 - 5 0 - 4 mole

mole

So)

X)

Na

NaF-KF-Li F-UFI, (10.9-43.5-44.5-1.1

13 0

METALLOGRAPHIC NOTES

Na

NaF-KF-Li F-UF.1 (10.9-43.5-44.5-1.1

ZrC

WEIGHT CHANGE (g/in. 2 )

CORRODANT

mole %)

Fluoride adheTing t o specimen

No a t t a c k a p p a r e n t

-0.0119

Bonding m a t e r i a l a p p e a r e d t o be l e a c h e d from specimen t o a d e p t h of 5 m i l s

-0.0037

Specimen showed t h a t some u n i f o r m s o l u t i o n had t a k e n p l a c e , b u t no t h i c k n e s s c h a n g e was i n v o l v e d

-0.0158

S u r f a c e a p p e a r e d t o be s l i g h t l y rough en ed

PERIOD ENDING MARCH 1 0 , 1953

F i g . 1 0 . 6 . Zirconium Carbide Cermet After Exposure t o s o d i u m f o r 100 hr a t 816OC.

m i x t u r e NaF-KF-LiF-UF4 ( 1 0 . 9 - 4 3 . 5 4 4 . 5 - 1 . 1 m o l e So) a p p e a r e d t o h a v e l i t t l e e f f ' e c t on t h e s e m a t e r i a l s , b u t i n t h e o n e t e s t w i t h NaF-ZrF4-UF, (46-50-4 mole % I , t h e specimen was a t t a c k e d t o a d e p t h of 5 m i l s (Fig. 10.7).

No s i g n i f i c a n t d i m e n s i o n a l c h a n g e s c o u l d be n o t e d i n any of t h e t e s t s .

T h e w e i g h t l o s s d a t a and t h e r e s u l t s of metallographic examination are g - i v e n i n T a b l e 10.5.

f t h e ARE-Be0 Blocks St i n Na a n d NaK. Two t e s t s h a v e b e e n p e r f o r m e d w i t h ARE b e r y l l i u m o x i d e o r b l o c k s h e q t e d for s e v e r a l h o u r s a t 8 1 0 째 C i n a t y p e 347 s t a i n l e s s s t e e l p o t c o n t a i n i n g Na or NaK. In the f i r s t test, the beryllium o x i d e wa:; i m m e r s e d i n 2 5 5 i n . 3 o f

sodium f o r 2 1 3 h r a t 816째C. Although no c r a c k i n g o r s p a l l i n g o f t h e b e r y l l i u m oxide wa$ n o t i c e a b l e immediately after the test, the surface imp e r f e c t i o n s apparent i n p a r t a of Fig. 10.8 o c c u r r e d a f t e r t h e t e s t s p e c i m e n had b e soaked i n alcohol and w a t e r .

I n t h e s e c o n d t e s t , t h e NaK w a s t r a n s f e r r e d t o the p o t with the b e r y l l i u m o x i d e when b o t h t h e N a K a n d t h e b e r y l l i u m o x i d e were a t room temperature.

The t e s t was r u n f o r 500 h r a t 816째C w i t h t h e b e r y l l i u m o x i d e i m m e r s e d i n 2 5 5 i n . 3 o f NaK. After the t e s t , the beryllium oxide was b a d l y c r a c k e d , a s can b e s e e n i n p a r t b' o f F i g . 10. 8.

The weight and d i m e n s i o n a l c h a n g e s n o t e d f o r b o t h t e s t s a r e g i v e n i n T a b l e 10.6.

131

ANP PROJECT QUARTERLY PROGRESS REPORT .

.

t

F

F i g . 1 0 . 8 . ARE Beryllium Oxide Blocks After S t a t i c T e s t s i n Na and NaK a t 816’C. . ( a ) I n Na f o r 213 h r ; ( b ) i n NaK f o r 500 h o u r s .

Seesaw T e s t s o f Be0 i n NaK. Ber y l l i u m o x i d e s p e c i m e n s 1 / 4 b y 1/4 by l i n , were t e s t e d i n NaK i n t h e r o c k e r furnace f o r 100 h r , with a hot-zone t e m p e r a t u r e o f a p p r o x i m a t e l y 830°C and a c o l d - z o n e t e m p e r a t u r e of app r o x i m a t e l y 450°C. S p e c i m e n s were crimped i n t o t h e h s t end of t h e t u b e t o prevent t h e i r s l i d i n g from t h e b o t end t o t h e c o l d end.

Specimens i n d i c a t e d i n T a b l e 10.7 as“1ow d e n s i t y ” had a d e n s i t y of approximately 2.27; t h o s e i n d i c a t e d a s “high d e n s i t y ” had a d e n s i t y o f approximately 2.83.

132

Specimens i n d i c a t e d a s “dehydrated ” were d r i e d f o r 2 4 h r a t 125°C b e f o r e test.

The i n f o r m a t i o n d e r i v e d f r o m these experiments is tabulated i n T a b l e 10.7.

I t i s e v i d e n t from t h e s e d a t a t h a t a f t e r t h e s p e c i m e n s were s t r i p p e d i n a l c o h o l t h e r e was some s l i g h t evidence of cracking in the h i g h - d e n s i t y s p e c i m e n s and some s l i g h t evidence of s p a l l i n g i n t h e low-density s p e c im e n s Convection Loop t e s t s o f Be0 i n NaK. E i g h t s p e c i m e n s o f Be0 1 / 4 by 1 / 4 by 1 / 2 i n . were p l a c e d i n a w i r e b a s k e t

.

i

PERIOD ENDING MARCH 1 0 , 1 9 5 3 i n t h e s u r g e tank o f a thermal conv e c t i o n l o o p , a n d NaK was p e r m i t t e d t o flow over the specimens a t a v e l o c i t y o f a b o u t 8 fpm f o r 212 h o u r s .

The t e m p e r a t u r e o f t h e NaK was 1150'F i n t h e c o l d l e g a n d lOOO'F i n t h e h o t l e g , and t h e s a m p l e s were i n c o n t a c t w i t h NaK a t 1500'F. T h e NaK s p e c i m e n s i n t h e s e c o n d t e s t were pretreated before exposure t o the h o t N a K :in t h e f o l l o w i n g m a n n e r : s p e c i m e n s 1 and 2 r e c e i v e d n o s p e c i a l p r e t r e a t m e n t ; s p e c i m e n s 3 and 4 w e r e t r e a t e d w i t h MgNO,; s p e c i m e n s 5 and 6 w e r e i m p r e g n a t e d w i t h AlF, a n d CaF,; s p e c i m e n s 7 and 8 w e r e t r e a t e d w i t h BeN03.

The t e s t r e s u l t s a r e g i v e n i n T a b l e 10.8.

I t i s n o t e w o r t h y t h a t s p e c i m e n s 1, 3 , 5 , a n d 7 were l o c a t e d a b o v e s p e c i mens 2. 4, 6 , and 8 , r e s p e c t i v e l y , i n t h e b a s k e t d u r i n g e x p o s u r e t o t h e NaK, and i n e a c h c a s e t h e u p p e r s p e c i m e n suffered t h e g r e a t e r l o s s i n weight.

S p e c i a l t r e a t m e n t o f Be0 t o i n c r e a s e i t s r e s i s t a n c e t o h o t NaK a p p e a r s t o o f f e r p o s s i b i l i t i e s , and f u r t h e r t e s t s a r e t o be c o n d u c t e d .

The e f f e c t of t h e d e n s i t y o f t h e s p e c i m e n c o u l d n o t be c o r r e l a t e d t o t h e w e i g h t l o s s e s i n these tests.

S o l u b i l i t y o f B e 0 in N a K .

Various workers have i n i t i a t e d experiments t o determine, i f possible, the e f f e c t o f NaK o n B e 0 a t . t e m p e r a t u r e s o f a p p r o x i m a t e l y 800'C i n b o t h s t a t i c and

BEFORE TEST

AFTER TEST

CHANGE

Length, i n .

5.9 14

5.917

+0.05

Width, i n .

3.706

3.708

+0.05

Weight,

3.154

3,221

+2.1

5.909 3.714

5.899

-0.17

Width, i n .

3.7 1 2

-0.05

Weight,

3. 160

3.205

+1.4

:1

Length, i n .

:1

(%I

AFTER CLEANING I N WATER AND DRYING

CHANGE

3.205

+1.6

3.187

+0.85

(%I

I!

TABLE 10.7. RESULTS OF SEES SPEXXNIEN

High d e n s i t y , d e h y d r a t e d

I

TESTS O F B e 0 I N N a K AFTER 100 h r AT 816'C

WEIGHT LOSS (g/in.

WEIGHT LOSS (96)

TOTAL WEIGHT LOSS (mg)

TOTAL Be0 FOUND BY ANALYSIS OF NaK FILTER AND CONTAINERS

0.0454

2.38

30.7

14.26

0.0286

1.25

18.9

4.97

0.0893

5. 15

47.0

9.91

0.0104

0.52

6.1

6.02

(mg)

' T h i s test tun f o r o n l y 16 h o u r s .

133

ANP PROJECT QUARTERLY PROGRESS REPORT dynamic t e s t s y s t e m s .

The w e i g h t l o s s e s o f t h e Be0 b l o c k s o b s e r v e d i n a number of i n s t a n c e s prompted a s e a r c h f o r t h e b e r y l l i u m t h a t had been removed from t h e b l o c k .

In those t e s t s f o r w h i c h t h e NaK was f i l t e r e d a t room t e m p e r a t u r e , t h e b e r y l l i u m found i n t h e f i l t r a t e c o r r e s p o n d e d t o a p p r o x i m a t e l y 3 ppm o f BeO, which was a very small p a r t o f t h e t o t a l beryllium removed from t h e b l o c k s .

Further examination revealed t h a t t h e ber y l l i u m o r t h e BeO, or b o t h , was l o c a t e d p r i m a r i l y on t h e w a l l s o f t h e c o n t a i n e r s t o which i t a d h e r e d t i g h t l y .

The q u e s t i o n t h e n a r o s e a s t o ' w h e t h e r o r n o t t h e b e r y l l i u m was removed f r o m t h e b l o c k a n d d e p o s i t e d on t h e w a l l by some p r o c e s s i n v o l v i n g s o l u b i l i t y o f Be or Be0 i n t h e NaK a t 800OC. Two t e s t s were p e r f o r m e d t o m e a s u r e In t h e s o l u b i l i t y i n NaK a t 8 0 0 째 C . t h e f i r s t t e s t , Be0 was c o n t a c t e d w i t h NaK a t 8OO0C f o r 6 h r i n t h e r e a c t i o n f i l t r a t i o n r i g previously described. 16) The MaK was f i l t e r e d a t a p p r o x i m a t e l y 8OO0C, and t h e f i l t r a t e w a s c o l l e c t e d i n a n i c k e l r e c e i v i n g tube.

B a s e d on t h i s s i n g l e experiment, t h e s o l u b i l i t y o f b e r y l l i u m i n NaKat 8OO0C c o r r e s p o n d s t o r o u g h l y 1 0 0 ppm, b u t i t i s n o t known w h e t h e r t h e m a t e r i a l d i s s o l v e d was Be or BeO. (6)ANP Quar. P r o g . R e p . D e c .

1439, F i g . 1 0 . 7 , p . 121.

10,

TABLE 10.8.

1 9 5 2 , ORNL-

In t h e second t e s t , a s t a i n l e s s s t e e 1 t h e r m a l c o n v e c t i o n l o o p was u s e d t o c i r c u l a t e NaK o v e r Be0 b l o c k s After suspended i n t h e s u r g e tank.

212 h r of c i r c u l a t i o n a t a flow r a t e o f 6 t o 10 fpm, a w e i g h t loss o f a b o u t 25% w a s m e a s u r e d f o r t h e B e 0 b l o c k s After the ( o r i g i n a l weight of 4 g).

NaK h a d b e e n d r a i n e d , t h e l o o p w a s s e c t i o n e d a s shown i n F i g . 1 0 . 9 .

The o p e r a t i n g temperatures of t h e loop a r e given on t h e f i g u r e , a l o n g with t h e a n a l y t i c a l r e s u l t s f o r t h e Be0 d e t e r m i n a t i o n s on t h e r e s p e c t i v e 3 1/2-in. sections.

The a n a l y t i c a l r e s u l t s show t h a t t h e t h r e e c o l d e s t (and lowest) s e c t i o n s of t h e l o o p c o n t a i n e d t h e g r e a t e s t concentrations of beryllium.

Since t h e a n a l y t i c a l d a t a show n o a c c u m u l a t i o n o f Be0 f r a g m e n t s i n t h e c o l d e s t p a r t of t h e t a n k , i t i s s u g g e s t e d t h a t a d i s s o l u t i o n p r o c e s s , g o v e r n e d by t h e temperature gradient, is responsible for the transfer of the material from t h e Be0 b l o c k t o t h e w a l l s . of t h e cold region.

Such a mechanism c o u l d be r e p r e s e n t e d by t h e f o l l o w i n g r e a c t i o n : 2NaK t 2Be0

e NazO

t K,O

-t

2Be

which, i f the r e a c t i o n proceeds s l i g h t l y t o t h e r i g h t a t 800째C and t h e b e r y l l i u m formed i s s o l u b l e i n NaK, w o u l d a c c o u n t f o r r e m o v a l o f

RESULTS OF TESTS OF Be0 IN NaK SPECIMEN NUMBER 6

7

8

0.002

0.000

0.001

0.005

0.004

0.091

0.076

0.069

0.062

0.162

0.119

9.6

6.8

6.0

4.9

4.7

11.1

2.50

2.54

2.45

2.82

2.65

2.66

2

Average l o s s i n dimensions per s u r f a c e , i n .

0.006

0.004

0.002

Loss of w e i g h t , g

0.152

0.120

(%I

D e n s i t y o f specimen

.

5

1

Loss of weight

11.5 2.60

9.6 2.45

("'Much o r a l l o f t h e w e i g h t l o s s may have been due t o t h e s h e d d i n g o f a t h i n s u r f a c e f i l m i n t h e alcohol bath.

134

,

PERIOD ENDING MARCH 1 0 , 1953

UNCLASSIFIED DWG. 48658

WEIGHT OF Be0 FOUND IN VARIOUS SECTIONS

SECTION NO.

Be0 (mg)

i

4.13 1.37 5.52

3 5 6 7 9 10 11

13 14% 17 18* 19

4.74

20 21 22

*14

(OF)

i 500

1360 1250

2.17 22.08 248.4 70.8 5.76 3.64 4.14

i5

AVERAGE TEMPERATURE

4140

1860 1370 144 0 I800 1480

6.72 27.48

and48 LOCATED UNDER HEATER

Fig. 10.9. Schematic Diagram o f Convection Loop f o r NaK-Be0 T e s t Showing Temperature and Be0 Recovered i n Various S e c t i o n s .

135

ANP PROJECT QUARTERLY PROGRESS REPORT b e r y l l i u m from solubility of 600°C t h a n a t alloyingin the

t h e Be0 b l o c k .

If the beryllium i s less a t 8OO0C, d e p o s i t i o n o r c o l d a r e a would o c c u r .

EFFECT OF ATMOSPHERE ON THE MASS

TRANSFEROF NICKELIN HYDROXIDES

H . J. B u t t r a m C. R. C r o f t F. K e r t e s z M a t e r i a l s Chemistry Division The i n c l i n e d - t u b e t e c h n i q u e p r e v i o u s l y d e s c r i b e d ( ' ) was u s e d f o r f u r t h e r s t u d y of t h e e f f e c t of v a r i o u s e x p e r i m e n t a l f a c t o r s on t h e mass t r a n s f e r o f n i c k e l by h y d r o x i d e s .

With a t e m p e r a t u r e g r a d i e n t o f 150°C ( 8 0 0 ° C a t t h e bottom and 650°C a t t h e t o p ) u n d e r h e l i u m atmosphere, sodium h y d r o x i d e t r a n s p o r t e d enough n i c k e l t o t h e l i q u i d l e v e l of t h e i n c l i n e d n i c k e l t u b e t o p l u g i t c o m p l e t e l y i n 48 h o u r s .

A s was p r e v i o u s l y m e n t i o n e d , h y d r o g e n g a s sweeping over t h e s u r f a c e of t h e m o l t e n h y d r o x i d e r e d u c e d t h e mass trans f e r considerably ; only polishing o f t h e h o t e n d and r o u g h e n i n g o f t h e c o l d e n d o f t h e t u b e c o u l d be observed.

The t e m p e r a t u r e g r a d i e n t was t h e n i n c r e a s e d t o 300°C ( 5 0 0 ° C a t t h e t o p and 800°C a t t h e b o t t o m ) , and a h y d r o g e n a t m o s p h e r e was u s e d .

Similar s a t i s f a c t o r y " r e s u 1 t s were o b t a i n e d ; t h e hydrogen l a r g e l y s u p p r e s s e d any crystal deposit a t the liquid level.

A t t e m p t s were made t o d e t e r m i n e t h e minimum p r e s s u r e a t w h i c h m a s s t r a n s f e r i s e f f e c t i v e l y i n h i b i t e d by hydrogen.

A 50 v o l % h e l i u m - 5 0 v o l % hydrogen m i x t u r e over t h e hydroxide gave s a t i s f a c t o r y r e s u l t s .

On t h e o t h e r h a n d , w i t h an a b s o l u t e h y d r o g e n p r e s s u r e o f 38 c m Hg established a s a m a n u a l l y a d j u s t e d vacuum the hydrogen system afforded no p r o t e c t i o n , p o s s i b l y because of t h e technique e mp l o y e d.

A n u m b e r o f o t h e r a t m o s p h e r e s was a l s o a p p l i e d o v e r sodium h y d r o x i d e i n the inclined tube test.

The u s e o f

-

-

( ? ) A N P Q u a r . P r o g . R e p . D e e . 1 0 , 1 9 5 2 , ORNL-

1439, p . 142 f f .

136

c a r b o n monoxide and f o r m i n g g a s (10% i- 90% N 2 ) d i d n o t h a v e a b e n e f i c i a l effect.

Water i n t h e h y d r o g e n , e v e n i n small quantities, resulted in c o n s i d e r a b l e mass t r a n s f e r .

Bubbling t h e hydrogen through water a t v a r i o u s temperatures resulted in nickel c r y s t a l d e p o s i t s i n amounts s i m i l a r to those obtained under a helium atmosphere.

A c o n t i n u o u s vacuum o v e r t h e system (which would remove any hydrogen formed d u r i n g t h e t e s t ) r e s u l t e d i n extremely heavy c o r r o s i o n and mass t r a n s f e r , and l e f t t h e hydroxide with a n i c k e l concentration o f u p t o 3%. H o w e v e r , when t h e t u b e was e v a c u a t e d a n d s e a l e d , t h e mass t r a n s f e r w a s much l e s s s e v e r e .

Dry a i r was d e f i n i t e l y l e s s h a r m f u l t h a n w e t hydrogen.

The u s e of commercial sodium h y d r o x i d e , which c o n t a i n s up t o 2% water, r e s u l t e d i n g r e a t l y reduced mass t r a n s f e r under d r y hydrogen.

One e f f e c t o f t h e d r y h y d r o g e n may b e t o s t r i p t h e w a t e r from t h e h y d r o x i d e .

In addition t o t h e tests with sodium h y d r o x i d e , e x p e r i m e n t s were made w i t h s o d i u m h y d r o x i d e - p o t a s s i u m hydroxide e u t e c t i c , w i t h pure potassium h y d r o x i d e , and w i t h l i t h i u m h y d r o x i d e .

With n o n e o f t h e s e m a t e r i a l s c o u l d t h e i n h i b i t i n g e f f e c t o f h y d r o g e n on t h e mass t r a n s f e r o f n i c k e l b e obtained; the reason for t h i s i s not yet clear.

More c l o s e l y c o n t r o l l e d experiments a r e planned.

H,

FUNDAMENTAL CORROSION RESEARCH

I d e n t i f i c a t i o n o f Corrosion Products from Convection Loops (D. C. H o f f m a n , Materials Chemistry Division). Cooling j e t s t h a t i m p i n g e d on t h e c o l d l e g o f an I n c o n e l t h e r m a l c o n v e c t i o n l o o p i n which t h e LiF-NaF-KF e u t e c t i c c o n t a i n i n g 1 . 8 m o l e % o f UF, w a s c i r c u 1a t i n g , p r o d u c e d p a r t i a 1 p 1u g s which p e r s i s t e d a f t e r t h e c o o l i n g j e t s were removed and c o u l d n o t b e l i q u e f i e d X-ray a t t e m p e r a t u r e s o f u p t o 650°C. a n a l y s i s of t h e p l u g s showed t h e p r e s e n c e o f KF and some m a t e r i a l t h a t

4

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 gave a s l i g h t l y s h i f t e d spectrum of K,NaCrF, Petrographic investigation substantiated the presence of t h i s compound and a l s o r e v e a l e d some b r i g h t m e t a l t h a t was shown t o b e n o n m a g n e t i c .

I n s p e c t i o n u n d e r b i n o c u l a r s (45X) .$:showed a n e t w o r k of c r y s t a l s , presumed t o be t h e K2NaCrF6, g r o w i n g i n w a r d from t h e t u b e w a l l s .

The coinpound K2NaCrF6 h a s a s o l u b i l i t y i n t h e NaF-KF-LiF e u t e c t i c o f 4 5 0 ppm C r ( I I 1 ) and 2 0 0 0 ppm C r ( I I 1 ) a t 500 a n d 65OoC, r e s p e c t i v e l y .

It therefore appears probable that K2NaCrF6 h a s b e e n r e s p o n s i b l e f o r plugging in t h i s loop, as w e l l a s i n o t h e r s , i n which t h e amount of m e t a l t r a n s f e r r e d was i n s u f f i c i e n t t o a c c o u n t f o r t h e phenomenon.

Of t h e t e n s t a i n l e s s s t e e l h a r p s t h a t were plugged while c i r c u l a t i n g t h i s m i x t u r e , s i x showed h i g h e r chromium c o n t e n t i n t h e c o l d l e g , one showed h i g h e r chromium c o n t e n t i n t h e h o t l e g , and t h e o t h e r t h r e e showed n o s y s t e m a t i c variation.

T h e K,NaCrF, c r y s t a l s a p p a r e n t l y f o r m an o p e n n e t w o r k t h a t g r a d u a l l y stops t h e flow without developing, under u s u a l operating conditions, e a s i 1y d e t e c t a b l e l o c a 1 c oncen t r a t i o n s The o b s e rv 21 t i on t h a t i n c r e a s ed ope r a t i n g temperatures postpone the onset of p l u g g i n g in s t a i n l e s s s t e e l l o o p s i s c o n s i s t e n t with t h i s explanation of t h e p l u g g i n g phenomenon.

P r e p a r a t i o n of S p e c i a l Complex F l u o r i d e s (B. J. S t u r m , L. G. O v e r h o l s e r , M a t e r i a l s Chemistry D i v i s i o n ) .

Prepar a t i o n s of K2LiCrF,, KNaLiCrFs, L i 2 N a C r F 6 , N a 2 L i C r F , , and NaCrF, h a v e b e e n made t o f u r n i s h s p e c i m e n s f o r x - r a y and o p t i c a l c r y s t a l l o g r a p h i c data.

C o n t i n u e d s t u d y o f t h e complex f l u o r i d e s of n i c k e l h a s n o t y e t e s t a b l i s h e d w h e t h e r d e f i n i t e compounds or s o l i d s o l u t i o n s e x i s t i n t h e c o m p o s i t i o n r a n g e b e t w e e n K,NiF, a n d Na2Ni F, A l s o , s e v e r a 1 simp l e f l u o r i d e s of the s t r u c t u r a l metals, including chromof l u o r i d e , f e r r o f l u o r i d e , n i c k e l f l u o r i d e , and f e r r o u s o x i d e , h a v e been

.

.

.

prepared f o r s t u d i e s of t h e i r e f f e c t on c o r r o s i o n by f u e l m i x t u r e s .

Chromic f l u o r i d e c a n be p r e p a r e d by t h e r m a l d e c o m p o s i t i o n o f (NH, ),CrF, a t t e m p e r a t u r e s n o t e x c e e d i n g 900°C; some CrF, i s formed a t h i g h e r t e m p e r a tures.

Chromous f l u o r i d e i s p r e p a r e d or a m i x t u r e o f by h e a t i n g (NH,),CrF, h y d r a t e d CrF, and NH,KF, t o 1200°C i n graphite crucibles.

The p r o d u c t from e i t h e r of t h e s e p r o c e d u r e s i s i d e n t i c a l w i t h t h a t o b t a i n e d by h y d r o f l u o r i n a t i o n o f m e t a l l i c chromium a t 800°C. Ferric f l u o r i d e i s p r e p a r e d by h y d r o f l u o r i n a t i o n o f u a n h y d r o u s " FeC1, a t 200 t o 300°C. F e r r o u s f l u o r i d e may b e p r e p a r e d by h e a t i n g ( N H 4 1 3 F e F 6 a t 750°C or, p r e f e r a b l y , by h y d r o f l u o r i n a t i o n o f FeC1, a t a maximum t e m p e r a t u r e o f 500°C. Nickel fluoride is b e s t p r e p a r e d by t h e r m a l d e c o m p o s i t i o n o f (NH,),NiF,.

Ferrous oxide is p r e p a r e d by d e c o m p o s i t i o n , u n d e r an a t m o s p h e r e o f CO,, o f f e r r o u s o x a l a t e p r e c i p i t a t e d from an a q u e o u s s o l u t i o n o f f e r r o u s ammonium s u l f a t e by ammonium oxalate.

The f e r r o u s o x i d e p r o d u c e d i s v e r y f i n e l y d i v i d e d and i s e a s i l y o x i d i z e d by room t e m p e r a t u r e a i r ; a l l h a n d l i n g o f t h i s compound r e q u i r e s a dry, i n e r t atmosphere.

Air O x i d a t i o n o f F u e l M i x t u r e s (R. P. M e t c a l f , M a t e r i a l s Chemistry Division).

S o l i d UF, i s known t o y i e l d UO,F, a n d UF, a s p r e d o m i n a n t r e a c t i o n p r o d u c t s when t r e a t e d w i t h oxygen a t h i g h t e m p e r a t u r e s . ( * * ' ) However, when m o l t e n NaUF5 i n a n i c k e l b o a t was t r e a t e d w i t h 40 t o 60 c c / m i n o f d r y a i r f o r 2 t o 6 h r a t 75OoC, no g a s e o u s uranium compounds were observed X-ray-diffraction techniques reveal t h e p r e s e n c e o f N i O , U,O,, and Na,NiF, among t h e s o l i d p r o d u c t s o f t h e reaction.

I n a d d i t i o n , s e v e r a l uni d e n t i f i e d p r o d u c t s t h a t may b e

.

F r i e d and N. R. D a v i d s o n , T h e R e a c t i o n v i t h D r y 0,; A N e r S y n t h e s i s of U F 6 , AECD2 9 8 1 ?May 1 9 4 5 ) . of UF

(9)S. S. K i r s l i s . T. S. M c l i l l a n a n d H . A. B e r n h a r d t , T h e R e a c t i o n of U r a n i u m T e t r a f l u o r r d e w l t h D r y O x y g e n , K-567 (March 1 5 , 1 9 5 0 ) .

137

ANP PROJECT QUARTERLY PROGRESS REPORT double f l u o r i d e s of n i c k e l a r e observed.

The a b s e n c e o f UO,F, a n d UO, a n d t h e l a c k of evidence f o r v o l a t i l i z a t i o n o f UF, a r e n o t e w o r t h y .

These r e s u l t s , a s w e l l a s t h e r a p i d c o r r o s i o n r a t e of n i c k e l i n c o n t a c t with molten f l u o r i d e s i n a i r , a r e consistent with t h e following r e a c t i o n mechanism :

138

--

2 N i + 0, 2Ni0 2NiO + UF, d UO, + PNiF, 3U0, + 0, U,O, 2NaF + NiF, Na,NiF,

It appears t h a t the container plays an i m p o r t a n t p a r t i n t h e mechanism o f a i r oxidation of uranium i n t h e m o 1t en f l u or i d e s

.

PERIOD ENDING MARCH 10, 1953 11. METALLURGY AND CERAMICS W. D.

Manly J . M. Warde Met a1 l u r gy D i v i s i o n

P

C o n e - a r c w e l d i n g i s now b e i n g a p p l i e d t o t h e p r o d u c t i o n o f t h e many tube-'to-header j o i n t s needed i n t h e construction of t h e complicated h e a t exchangers for a i r c r a f t reactors.

S i n c e t h e h e a t e x c h a n g e r s a r e t o be operated a t a moderately high pressure f o r the temperature involved, dished header s h e e t s a r e desired.

The d i s h e d h e a d e r s h e e t s i m p o s e a new p r o b l e m o f unequal a r c distances i n cone-arc welding.

S t u d i e s a r e u n d e r way t o s e l e c t t h e proper c o n d i t i o n s t o minimize t h i s e f f e c t s o t h a t c o n s i s t e n t l y sound w e l d s c a n be produced.

In the fabrication of l a r g e h e a t exchanger test u n i t s by N i c r o b r a z i n g , d i f f i c u l t i e s d u e t o d i l u t i o n a n d e m b r i t t l e m e n t by t h e b r a z i n g a l l o y were e n c o u n t e r e d .

It i s p o s s i b l e t o s u b s t i t u t e o t h e r alloys for this brazing cycle that w i l l n o t c a u s e s e v e r e d i l u t i o n and embrittlernent, and t h e e v a l u a t i o n o f high-temperature brazing alloys is continuing.

The m e l t i n g p o i n t o f t h e p a l l a d i u m - n i c k e l b r a z i n g a l l o y was l o w e r e d by a d d i t i o n s o f g e r m a n i u m , The e f f e c t s o f time a t t h e b r a z i n g t e m p e r a t u r e a n d o f j o i n t s p a c i n g on t h e strength p r o p e r t i e s of Nicrobrazed j o i n t s h a v e been d e t e r m i n e d , A summary of the butt-braze t e n s i l e s t r e n g t h d a t a o b t a i n e d on t h e v a r i o u s b r a z i n g alloys is presented.

A search for a satisfactory brazing alloy for the joining of stainlesss t e e l - or Inconel-clad copper f i n s t o I n c o n e l and s t a i n l e s s s t e e l t u b e s h a s proved f r u i t f u l , and t h e o x i d a t i o n characteristics of the alloys t h a t show good f l o w a b i l i t y on I n c o n e l a r e now b e i n g s t u d i e d .

However, i t h a s been d e m o n s t r a t e d t h a t a c h r o m e - p l a t e d , high-conductivity, copper f i n does n o t have s u f f i c i e n t o x i d a t i o n r e s i s t a n c e for t h i s application,

The e f f e c t s o f e n v i r o n m e n t and o f s u r f a c e t r e a t m e n t on t h e c r e e p a n d s t r e s s - r u p t u r e p r o p e r t i e s of Inconel a r e s t i l l being studied, Preoxidized s p e c i m e n s were t e s t e d i n a r g o n , and i t was f o u n d t h a t t h e c r e e p p r o p e r t i e s were q u i t e s i m i l a r t o t h o s e d e t e r m i n e d i n argon; therefore surface oxidation is not the controlling factor i n the l o n g e r r u p t u r e times o b s e r v e d i n t h e a i r tests Control rod i n s e r t s of a mixture of boron c a r b i d e and i r o n a r e b e i n g p r e p a r e d by p o w d e r m e t a l l u r g y t e c h n i q u e s f o r t h e GE-ANP p r o g r a m .

The c o n t r o l r o d i n s e r t s must be m e t a l l u r g i c a l l y bonded t o t h e o u t s i d e s t a i n l e s s s t e e l t u b e , and v a r i o u s brazing alloys a r e being studied f o r this application.

Boron c a r b i d e s a f e t y r o d s f o r t h e Tower S h i e l d i n g F a c i l i t y were a l s o p r o d u c e d .

Special heats of a high-purity Inconel a r e being prepared f o r corrosion tests, In the subsequent e x t r u s i o n o f I n c o n e l t u b e s , one o f t h e b i g g e s t d i f f i c u l t i e s t o overcome i s the selection of a proper extrusion lubricant.

A s a t i s f a c t o r y tube has been p r o d u c e d by t h e u s e o f g l a s s a s a lubricant.

In other studies, the o x i d a t i o n c h a r a c t e r i s t i c s o f columbium a r e b e i n g i n v e s t i g a t e d , and some e x p l o r a t o r y r u n s h a v e been made on t h e production of materials for use as pump s e a l s o f t h e f a c e - s e a l t y p e b e i n g s t u d i e d by t h e E x p e r i m e n t a l E n g i n e e r i n g Group.

An e n a m e l w i t h h i g h b o r o n c o n t e n t was a p p l i e d on a s h i e l d t e s t p l a t e , b u t a p a r t o f t h e s u r f a c e was n o t w e l l covered and a second a t t e m p t was necessary.

Two c e r m e t f u e l e l e m e n t s are described, Impregnation of hexagonal beryllium oxide blocks with b e r y l l i u m and m a g n e s i u m n i t r a t e s a n d

139

ANP PROJECT QUARTERLY PROGRESS REPORT c a l c i u m a n d aluminum f l u o r i d e s was attempted.

The f l u o r i d e s f i l l e d t h e p o r e s , and t h e magnesium i m p r e g n a t i o n shows p r o m i s e . c

WELDING AND BRAZING RESEARCH

P. P a t r i a r c a G. M. S l a u g h t e r

V . G. Lane C. E , S c h u b e r t

Metallurgy Division

Cone-Arc Welding.

The d e s i g n o f r e c e n t fuel-to-NaK h e a t exchangers , f o r reactor research has necessitated the f a b r i c a t i o n o f s m a l l , Inconel, tubeto-header subassemblies t h a t can be b u i l t i n d i v i d u a l l y and t h e n be w e l d e d i n t o one, l a r g e r , t e s t assembly.

It i s o b v i o u s from t h e l a r g e number o f t u b e - t o - h e a d e r j o i n t s t o be h e l i a r c welded t h a t a s e m i a u t o m a t i c method would be e x t r e m e l y d e s i r a b l e .

As a r e s u l t , the cone-arc welding technique was a p p l i e d t o p r e l i m i n a r y e x p e r i m e n t s i n t h i s subassembly f a b r i c a t i o n . S i n c e t h e h e a t e x c h a n g e r i s t o be o p e r a t e d a t a m o d e r a t e l y h i g h p r e s s u r e for t h e temperature involved, dished header If the plane of sheets are desirable. t h e bottom o f t h e h e a d e r i s k e p t l e v e l during welding, it is obvious t h a t unequal a r c d i s t a n c e s w i l l p r e v a i l a r o u n d t h e p e r i p h e r y o f many o f t h e tubes.

Thus t h e a b i l i t y t o make c o n s i s t e n t l y s o u n d w e l d s on t h e d i s h e d header depends, t o a l a r g e degree, upon t h e s e l e c t i o n o f c o n d i t i o n s t h a t w i l l minimize t h e s e v a r i a t i o n s i n a r c distance.

Offsetting the tungsten e l e c t r o d e from t h e c e n t e r o f t h e t u b e p r i o r t o w e l d i n g and u s i n g a b a l l - a n d s o c k e t j o i n t arrangement from which t h e h e a d e r c a n be p i v o t e d a r e o b v i o u s means o f e q u a l i z i n g t h e a r c d i s t a n c e around t h e tube periphery.

P r e l i m i n a r y e x p e r i m e n t s on t h i s problem have c o n s i s t e d o f i n v e s t i g a t i n g the variables of arc current, arc t i m e , and e l e c t r o d e d i s t a n c e r e q u i r e d t o produce c o n s i s t e n t l y leak- t i g h t welds.

An e x p e r i m e n t a l , c o n e - a r c w e l d e d , t e s t s p e c i m e n i s shown i n F i g . 11.1, w h i c h i l l u s t r a t e s t h e

140

F i g . 11.1.

An E x p e r i m e n t a l Heat Exchanger Subassembly A f t e r Cone-Arc Welding.

tendency f o r uneven m e l t i n g around some o f t h e t u b e p e r i p h e r i e s when t h e t u n g s t e n e l e c t r o d e was c e n t e r e d o v e r the tube with the header p l a t e a x i s perpendicular t o the electrode axis.

The d i a m e t e r of t h e header p l a t e i s 2 1/4 i n , and t h e p l a t e t h i c k n e s s i s 0 . 1 2 5 i n c h . The t u b i n g h a s a n o u t s i d e diameter of 0.148 i n . with a 0.025-in. w a l l , and t h e h o l e c e n t e r - t o - c e n t e r d i s t a n c e i s approximately 0.378 inch.

Some d i f f i c u l t i e s h a v e b e e n e n countered with j o i n t s t h a t are not pressure-tight, but it i s expected t h a t f u r t h e r experiments w i l l enable t h e production of subassemblies t h a t w i l l be c o m p l e t e l y s o u n d , I n each t e s t a s s e m b l y t h a t h a s been f a b r i c a t e d t h u s f a r , o n l y o n e or two j o i n t s were u n s a t i s f a c t o r y ; t h e o t h e r j o i n t s were pressure-tight t o a i r a t approximately 60 p s i g .

This indicates t h a t an improvement i n t e c h n i q u e or a s l i g h t v a r i a t i o n i n welding conditions should h e l p t o improve t h e q u a l i t y o f t h e s e c o n e - a r c welded j o i n t s .

F a b r i c a t i o n o f Heat Exchanger U n i t s .

A second l a r g e s o d i u m - t o - a i r h e a t e x c h a n g e r a s s e m b l y was f a b r i c a t e d by

t

,

PERIOD ENDING MARCH 1 0 , 1 9 5 3 N i c r o b r a z i n g and t h e o v e r - a l l a p p e a r a n c e , a s :shown i n F i g . 1 1 . 2 , was much b e t t e r than t h a t of the f i r s t assembly.(') Changes i n c o r p o r a t e d i n t h e brazing procedure f o r t h i s second u n i t were t h e u s e o f l e s s e r q u a n t i t i e s of N i c r o b r a z , t h e u s e o f s e v e r a l a s p i r a t o ~ st o p r o m o t e m o r e e v e n h y drogen flow between t h e f i n s , t h e b u i l d u p o f t h e whole assembly o f f t h e can bottom t o overcome t h e d r a s t i c i n i t i a l h e a t i n g r a t e , and t h e u s e o f a s l i g h t l y lower b r a z i n g temperature.

P r e s s u r e t e s t i n g w i t h h e l i u m , however, revealed the presence of a leak i n the tube-to-fin matrix. A technique was d e v e l o p e d t o s e a l o f f t h i s t u b e on e a c h s i d e o f t h e l e a k by r e b r a z i n g , (l)ANP Q u a r . P r o g . R e p .

Dec.

1 0, 1 9 5 2 , ORNL-

1439, p . 1 6 4 .

5

Fig. 11.2. Sodium-to-Air Radiator After N i c r o b r a z i n g .

b u t upon p e r f o r m i n g t h i s o p e r a t i o n , several other leaks appeared i n o t h e r tubes.

I t i s hoped t h a t t h e damaging e f f e c t s c a u s e d by s u b s e q u e n t N i c r o b r a z i n g o p e r a t i o n s c a n be e l i m i n a t e d by a d o p t i n g a m o d i f i e d d e s i g n t h a t would p e r m i t t h e h e l i a r c w e l d i n g o f t h e tube- to-header j o i n t s and t h e j o i n t s i n the heavier manifold s e c t i o n s .

By t h e u s e o f t h e s i n g l e - b r a z e m e t h o d , any l e a k s i n t h e t u b e - t o - f i n m a t r i x a f t e r b r a z i n g c a n b e e l i m i n a t e d from t h e c o o l a n t c i r c u i t by p l u g w e l d i n g the proper tubes, The t u b e - t o - h e a d e r w e l d s c o u l d t h e n b e made by m a n u a l h e l i a r c welding, a s could the other j o i n t s i n t h e m a n i f o l d c i r c u i t . With some minor c h a n g e s i n r a d i a t o r d e s i g n , i t seems p r o b a b l e t h a t c o m p l e t e d u n i t s c o u l d be f a b r i c a t e d w i t h l e s s c h a n c e of o b t a i n i n g leaky j o i n t s , By e l i m i n a t i n g several high- temperature brazing o p e r a t i o n s , g r a i n growth i n t h e s t a i n l e s s s t e e l t u b e s c o u l d be m i n i m i z e d , a s could e m b r i t t l i n g of t h e base metal by b r a z i n g a l l o y d i f f u s i o n .

I t i s w e l l known t h a t c e r t a i n Nicrobrazed s t a i n l e s s steel j o i n t s e x h i b i t b r i t t l e n e s s t o a high degree.

This f a c t o r , coupled with t h e a l l o y i n g away o f t h e t u b e w a l l by b r a z i n g a l l o y d i l u t i o n and d i f f u s i o n , i s t h o u g h t t o be r e s p o n s i b l e f o r a m a j o r p o r t i o n o f t h e l e a k s e n c o u n t e r e d i n h e a t exchanger fabrication.

S i n c e i t seems p r o b a b l e t h a t j o i n t b r i t t l e n e s s may a l s o b e a s s o c i a t e d w i t h d i l u t i o n and d i f f u s i o n phenomena, a s y s t e m a t i c s t u d y o f t h i s p r o b l e m h a s been i n i t i a t e d .

Nicrobrazed tube- to- f i n j o i n t s a r e b e i n g p r e p a r e d by u s i n g 0 . 0 1 0 - i n . t h i c k , t y p e 302 s t a i n l e s s s t e e l fin m a t e r i a l and 0.150-in.-ODJ 0 , 0 1 6 - i n . w a l l , t y p e 304 s t a i n l e s s s t e e l t u b i n g f o r s t u d y i n g , by m e t a l l o g r a p h i c e x amination, the effects of (1) the quantity of brazing alloy used, (2) the brazing temperathre for a given t i m e , and ( 3 ) t h e b r a z i n g t i m e f o r a given temperature, S m a l l , medium, a n d l a r g e amounts o f b r a z i n g a l l o y a n d

141

ANP PROJECT QUARTERLY PROGRESS REPORT t h e t i m e a t t e m p e r a t u r e , w h i c h may v a r y f r o m 1 0 min t o 1 8 h r ( f o r an overnight brazing cycle), are being investigated.

The c h o i c e of b r a z i n g t e m p e r a t u r e i s b e i n g v a r i e d from 20째C a b o v e t h e m e l t i n g p o i n t t o a maximum o f 120째C a b o v e t h e m e l t i n g p o i n t .

S i n c e i t may be a d v i s a b l e t o f i n d a s u b s t i t u t e f o r N i c r o b r a z i n t h e cons t r u c t i o n of sodium-to-air h e a t exc h a n g e r , two o t h e r b r a z i n g a l l o y s a r e being subjected t o similar diffusion and d i l u t i o n i n v e s t i g a t i o n s .

An 82% Au-18% N i a l l o y i s t y p i c a l o f t h e lower-me1 t i n g , d u c t i l e , o x i d a t i o n r e s i s t a n t b r a z i n g a l l o y s t h a t , unfortunately,are incompatible with sodium b u t may be u s e d f o r t u b e - t o - f i n c o n s t r u c t i o n i f d i l u t i o n and d i f f u s i o n c a n be c o n t r o l l e d .

A 6 0 % Mn-40% N i a l l o y h a s been shown t o be c o m p a t i b l e w i t h sodium, b u t i t i s s l i g h t l y a t t a c k e d i n high- temperature oxidation t e s t s .

I t i s a l s o somewhat b r i t t l e i n t h e a s brazed condition.

Brazing of Copper to Inconel. The need f o r a s a t i s f a c t o r y b r a z i n g a l l o y f o r j o i n i n g copper f i n s t o Inconel t u b i n g and f o r e d g e - s e a l i n g s h e a r e d , I n c o n e l - c l a d , copper f i n s h a s been e m p h a s i z e d . The r e s u l t a n t b r a z e s h o u l d

TABLE 11.1.

be r e s i s t a n t t o o x i d a t i o n a t 1500"F, should preferably serve a s a d i f f u s i o n b a r r i e r a g a i n s t copper p e n e t r a t i o n i n t o t h e I n c o n e l d u r i n g s e r v i c e , and s h o u l d have a r e l a t i v e l y h i g h s t r e n g t h a t 1500째F. I t i s l i k e l y t h a t some a l l o y o t h e r than a copper-base a l l o y would b e s t f i l l t h e s e r e q u i r e m e n t s .

An e x p e r i m e n t a l , m o d i f i e d , N i c r o b r a z a l l o y , which m e l t s a t a p p r o x i m a t e l y 1850"F, a p p e a r s t o be v e r y p r o m i s i n g , a s d o a l l o y s o f 82% Au-18% N i a n d 90% Au-10% Co. O x i d a t i o n t e s t s a t 1500째F on b r a z e d I n c o n e l j o i n t s i n d i c a t e n o a p p r e c i a b l e a t t a c k . A l i s t of s e v e r a l a l l o y s , c u r r e n t l y being i n v e s t i g a t e d , t h a t m e l t i n t h i s medium t e m p e r a t u r e r a n g e i s g i v e n i n T a b l e 11.1. F l o w a b i l i t y t e s t s on I n c o n e l h a v e b e e n made, and t h e r e s u l t s o f t h e s e t e s t s a r e a l s o l i s t e d i n T a b l e 11.1.

E d g e - s e a l i n g e x p e r i m e n t s on chromiump l a t e d copper d i s k s a r e b e i n g conducted, and techniques a r e being studied for obtaining a satisfactory e d g e s e a l on t h e s e d i s k s .

A t the present, t h e f i n edges a r e being suspended i n a s l u r r y o f t h e modified, l o w - m e l t i n g - p o i n t , N i c r o b r a z a l l o y and s l o w l y r o t a t e d u n t i l an even c o a t i n g of brazing a l l o y i s deposited.

The

PROPERTIES OF THE MEDIUM-TEMPERATURE BRAZING ALLOYS CURRENTLY BEING INVESTIGATED

BRAZING ALLOY

MELTING POINT (OF)

BRAZING TEMPERATURE (OF)

FLOWABI LI TY ON INCONEL

METHOD OF APPLICATION

95.5% Cu-4.5% Be

1590

1750

Poor

Powder

92% Cu-8% S i

1530

17 00

Poor

Powder

1 5 % Cu-25% Sn

1470

1600

Good

Powder

Low-me1 t i n g - p o i n t N i c r o b r a z

1800

1850

Good

Powder

82% Au-18% N i

1800

1850

E x c e l 1e n t

Sheet

90% Ag-10% CU

1600

1800

Poor

Sheet

90% Au-10% Co

1830

187 0

Good

Sheet

95% Ag-5% Ge

1650

1700

Poor

Sheet

90% Cu-10% Ge

1800

1870

Good

Sheet

142

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 f i n i s then edgebrazed i n a hydrogen atmosphere.

A n o t h e r method t o be i n v e s t i g a t e d f o r c o v e r i n g t h e s e exposed copper edges is t h e p r e p l a c i n g of a f i n e wire of brazing a l l o y i n the c r e v i c e f o r m e d by c h e m i c a l l y e t c h i n g away a s m a l l amount o f c o p p e r i n n i t r i c acid.

It is expected t h a t t h i s l a t t e r technique, i f s u c c e s s f u l , w i l l prevent f i n d i s t o r t i o n , which is b e l i e v e d t o be due t o u n a v o i d a b l e nonuniform w e t t i n g o f t h e f i n p e r i p h e r y by brazi

EVALUATION TESTS OF BRAZING ALLOYS

P. P a t r i a r c a G. M. S l a u g h t e r

V. G. C. E.

Lane Schubert Met a 1 l u r g y D i v i s i o n

l o w e r t h e m e l t i n g p o i n t o f t h e 60% Pd40% N i b r a z i n g a l l o y , 5% germanium was added.

T h i s a l l o y c a n be c o n s i s t e n t l y brazed a t 2150"F, which is i n t h e b r a z i n g r a n g e o f t h e m o r e common Nicrobraz alloy.

Static corrosion t e s t s on b r a z e d j o i n t s i n t h e m o l t e n fluoride s a l t s indicate that there is o n l y s l i g h t a t t a c k by m o l t e n NaF-KFLiF-UF, ( 1 0 . 9 - 4 3 . 5 - 4 4 . 5 - 1 . 1 mole % I , a s shown i n F i g . 1 1 . 3 , w h e r e a s s e v e r e a t t a c k i s p r e s e n t on t h e s a m p l e immersed i n NaF-ZrF4-UF, ( 4 6 - 5 0 - 4 mole % ) , F i g . 1 1 . 4 .

E f f e c t o f B r a z i n g Time on J o i n t Strength.

A review of r e s u l t s of r e c e n t and p r e v i o u s e x p e r i m e n t s c o n ducted t o evaluate the e f f e c t of t i m e a t t h e b r a z i n g t e m p e r a t u r e on t h e j o i n t s t r e n g t h of Nicrobrazed Inconel j o i n t s shows t h a t t h e e f f e c t o f t i m e

F i g . 1.1.3. Inconel J o i n t Brazed w i t h a 60% Pd-35% Ni-5% Ge Alloy A f t e r 100 hr a t 1500'F i n NaF-KF-LiF-UF, ( 1 0 . 9 - 4 3 . 5 - 4 4 . 9 - 1 . 1 mole % ) . E t c h e d w i t h a q u a regia, 10W. 143

ANP PROJECT QUARTERLY PROGRESS REPORT

Y-8701

.

*

b

*

r a t 1500'F

i n NaF-ZrF,-UF4

( 4 6 - 5 0 - 4 mole %).

not so important as the previously o r t e d l i m i t e d d a t a i n d i c a t e d . The room t e m p e r a t u r e s t r e n g t h s o f t h e s e j o i n t s a r e g e n e r a l l y much l e s s t h a n t h e s t r e n g t h o f t h e b a s e I n c o n e l and do n o t v a r y a p p r e c i a b l y w i t h t i m e a t t e m p e r a t u r e . Only o c c a s i o n a l l y d o e s a j o i n t e x h i b i t high t e n s i l e s t r e n g t h a t room t e m p e r a t u r e , a n d t h e p r e v i o u s r e s u l t s w e r e a p p a r e n t l y d i s t o r t e d by these infrequent high values.

A summary o f t h e d a t a i s g i v e n i n T a b l e 1 1 . 2 ; f o u r t e n s i l e b a r s were t e s t e d f o r e a c h b r a z i n g time, It is expected t h a t t h e b r a z i n g time w i l l have a g r e a t e r e f f e c t w i t h s t a i n l e s s s t e e l , because the width of t h e d i f f u s i o n zone i s g e n e r a l l y l a r g e r .

The c o m p o s i t i o n o f I n c o n e l i s s i m i l a r

144

Etche

t o t h a t of Nicrobraz, w l t n i c k e l , chromium, a n and t h e r e f o r e d i f f u s what h i concentr strengths a t 1500" high, as fractures often occur i n the base metal.

E f f e c t o f S p a c i n g on B r a z e d J o i n t S t r e n g t h . An i n v e s t i g a t i o n was c o n ducted t o determine the e f f e c t of j o i n t s p a c i n g on t h e s h o r t - t i m e , room-temperature , t e n s i l e s t r e n g t h o f Nicrobrazed Inconel j o i n t s .

Four b u t t - b r a z e d t e n s i l e b a r s were p r e p a r e d f o r e a c h j o i n t s p a c i n g of 0.005, 0.010, 0 . 0 1 5 , and 0.020 i n c h . The r e s u l t s o f

t

PERIOD ENDING MARCH 10, 1953

TIME AT 2150°F (min)

AVERAGE ROOM-'IEMF'ERATURE TENSILE STRENGTH OF BRAZED JOINTS ( p s i ) ( 0 . 2 5 2 - i n . s p e c i m e n )

(%I

5

34,900

40

10

40,100*

46

20

32,900

38

30

31,400

36

this investigation indicate that j o i n t spacing i s not a c r i t i c a l factor i n t h e room-temperature t e n s i l e s t r e n g t h of NicroErazed Inconel j o i n t s , a t l e a s t within t h e ranges investigated.

This range should cover n e a r l y a l l a p p l i c a t i o n s , s i n c e t h e e f f e c t of a s h r i n k f i t would t e n d t o b e l o s t d u r i n g t h e f u r n a c e b r a z i n g o p e r a t i o n , and a s p a c i n g o f o v e r 0.020 i n . would r e s u l t i n extremely poor f i t u p . t

JOINT EFFICIENCY

S t r e n g t h of Brazed J o i n t s w i t h V a r i o u s IBase M e t a l s .

Butt-braze t e n s i l e d a t a on t h e 73.5% Ni-16.5% Cr10.0% S i a l l o y i n d i c a t e t h a t t h e b a s e m e t a l c o m p o s i t i o n may b e a v e r y important factor i n determining the subsequent t e n s i l e strengths of brazed j o i n t s .

The average of t h e room-temperature t e n s i l e s t r e n g t h s of t h e I n c o n e l j o i n t s was 33,700 p s i .

S i m i l a r t e s t s on b r a z e d t y p e 3 1 6 s t a i n l e s s s t e e l showed an a v e r a g e t e n s i l e s t r e n g t h o f 64,400 p s i , which i s nearly double the value recorded f o r I n c o n e l . The e l e v a t e d - t e m p e r a t u r e t e s t s f o r both base m e t a l s gave excellent results. Joint efficiencies o f 99% w e r e o b t a i n e d € o r I n c o n e l , a n d e f f i c i e n c i e s o f 98% w e r e o b t a i n e d f o r t y p e '316 s t a i n l e s s s t e e l .

N i c r o b r a z e d j o i n t s on s t a i n l e s s s t e e l a l s o had h i g h e r t e n s i l e s t r e n g t h s t h a n N i c r o b r a z e d j o i n t s on I n c o n e l .

The a v e r a g e , r o o m - t e m p e r a t u r e , t e n s i l e strength for s t a i n l e s s steel j o i n t s

was 6 8 , 8 0 0 p s i , w h e r e a s t h e c o r r e s p o n d i n g v a l u e f o r I n c o n e l was 3 4 , 9 0 0 psi.

T h e 1500°F t e n s i l e t e s t s a g a i n gave evidence of j o i n t e f f i c i e n c i e s a p p r o a c h i n g 100% € o r b o t h b a s e m e t a l s .

A summary of' a m a j o r p o r t i o n o f t h e butt-braze t e n s i l e data obtained thus f a r i s p r e s e n t e d i n T a b l e 11.3.

The value l i s t e d for t h e room-temperature s t r e n g t h of Nicrobrazed Inconel j o i n t s i s t h a t r e s u l t i n g from a s e r i e s of t e s t s i n which some s p e c i m e n s f r a c t u r e d a t values nearly equal t o the t e n s i l e strength of Inconel.

Hence, t h i s a v e r a g e v a l u e i s somewhat h i g h e r t h a n t h e v a l u e s shown i n T a b l e 1 1 . 2 , i n which no d a t a w e r e r e c o r d e d t h a t i n d i cated such high trends.

Also the v a l u e s of j o i n t e f f i c i e n c y f o r s t a i n less s t e e l j o i n t s are only approximate because the 0.252-in.-dia s t a i n l e s s s t e e l t e n s i l e b a r s have n o t y e t been t e s t e d a f t e r t h e y were s u b j e c t e d t o t h e brazing cycle.

CREEP-RUPTURE TESTS OF STRUCTURAL METALS

R . B. O l i v e r D. A. D o u g l a s

J . W. Woods C. W . Weaver

Metallurgy Division

P r e o x i d i z e d I n c o n e l i n Argon.

It was p r e v i o u s l y r e p o r t e d ( 2 ) t h a t t h e environment surrounding t h e specimen (2)R. B . O l i v e r , D . A . D o u g l a s , K . W . R e b e r , J . W . W o o d s , and C . W . W e a v e r , ANP Q u a r . P r o g .

R e p . D e c . I O , 1 9 5 2 , ORNL-1439, p . 159.

145

ANP PROJECT QUARTERLY PROGRESS REPORT TABLE 11.3.

BUTT-BRAZE TENSILE DATA FOR SEVERAL HIGH-TEMPERATURE BRAZING ALLOYS TEMPERATURE

BASE METAL

BRAZING ALLOY

(OF)

Nicrobraz

60% Pd-40% N i

75% Ag-20% Pd-5% Mn

47 , 000

54

1500

24 , 500

100

Room

87,600

100

1500

21,000

93

Room

7 5,400

92

1500

22,400

88

Room

33,700

39

1500

23,100

99

Type 316 s t a i n l e s s s t e e l

Room

64,400

79

1500

25,000

98

Inconel

Room

55,900

64

1500

19,700

85

Inconel

Inconel

d u r i n g t e s t would h a v e a s i g n i f i c a n t e f f e c t on t h e c r e e p r a t e and r u p t u r e life.

Results obtained during the past quarter continue t o indicate t h a t t h e p r o p e r t i e s a r e b e s t when t h e I n c o n e l i s t e s t e d i n a i r , p o o r e s t when t e s t e d i n a hydrogen atmosphere, and i n t e r m e d i a t e when t e s t e d i n a r g o n . The r u p t u r e l i f e observed i n tests i n a h y d r o g e n a t m o s p h e r e was o f t h e o r d e r o f o n e - t e n t h t h e l i f e o b s e r v e d when t e s t e d i n a i r ; t h i s observation holds f o r s t r e s s e s o f 4000 p s i or l e s s . One hypothesis regarding the long rupture l i f e i n a i r involved a strengthening a c t i o n by t h e o x i d e f i l m formed d u r i n g t h e e a r l y p a r t of the test.

To t e s t t h i s p o s s i b i l i t y , a s e r i e s of specimens was h e a t e d i n a i r f o r 2 0 0 h r a t 815째C t o form s u c h a f i l m .

The p r e o x i d i z e d s p e c i m e n s were t h e n t e s t e d a t 815째C i n a r g o n , s t r e s s e d t o 2500, 3500, and 4500 p s i .

In the t h r e e t e s t s , t h e r u p t u r e t i m e s were f a r s h o r t o f t h e r u p t u r e times i n a i r , a n d were v e r y c l o s e t o t h e l i f e when tested i n argon.

I t i s t o be n o t e d

146

JOINT EFFICIENCY (%)

Room

I n c one 1

Type 316 s t a i n l e s s s t e e l

73.5% Ni-16.5% Cr-10.0% S i

TENSILE STRENGTH (psi1

t h a t t h e e l o n g a t i o n d u r i n g t e s t was much g r e a t e r t h a n t h a t o b s e r v e d i n o t h e r e n v i r o n m e n t s , a n d t h e r e was n o evidence of cracking i n the film.

F i g u r e 11.5 shows t h e s t r a i n vs. t i m e r e l a t i o n s h i p s of t h e b r i g h t and t h e preoxidized specimens t e s t e d i n argon.

T h e s e r e s u l t s c o u l d mean e i t h e r t h a t n i t r o g e n r a t h e r t h a n o x y g e n was t h e c o n t r o l l i n g f a c t o r or, a s i s more p r o b a b l e , t h a t t h e o x i d e f i l m formed s t r e s s r i s e s when i t c r a c k e d a n d t h a t t h i s a c t i o n , i n t u r n , promoted t h e integranular cracking that ultimately 1 ed t o f a i l u r e .

Peened Inconel in Argon. S p e c i m e n s o f I n c o n e l have been h e a v i l y peened w i t h f i n e s t e e l s h o t and a r e now b e i n g tested i n argon.

This mechanical working of t h e specimen s u r f a c e h a s i n c r e a s e d t h e r u p t u r e l i f e i n comparison with the l i f e of specimens t h a t did not receive t h i s treatment.

Also, t h e c r e e p r a t e f o r t h e peened s p e c i m e n i s much l o w e r t h a n t h a t observed f o r o t h e r specimens a t t h e same s t r e s s i n a n y a t m o s p h e r e .

It i s

c

t

i

* t

1

P E R I O D ENDING MARCH 1 0 , 1 9 5 3

UNCLASSIFIED

0

100

200

300

400

500

600

700

600

900

1000

1100

1200

1300

1400

1500

TIME (hr)

F i g . 11.5.

S t r a i n v s . T i m e c u r v e s f o r C o n t r o l and P r e o x i d i z e d I n c o n e l S p e c i mens a t 1500째F i n Argon.

improbable t h a t t h i s e f f e c t is t h e r e s u l t of r e s i d u a l compressive stress

i n d u c e d hy t h e p e e n i n g a c t i o n , s i n c e such s t r e s s e s would r e c o v e r a t a temperature lower than t h e test tempera t u r e . I t i s hoped t h a t m e t a l l o g r a p h i c examinati.on w i l l f u r n i s h a c l u e f o r e x p l a i n i n g t h e improved p r o p e r t i e s r e s u l t i n g from t h e p e e n i n g .

E f f e c t o f I n c o n e l G r a i n S i z e on T i m e t o Rupture.

As a g e m e n t , f i n e - g r a i n e d I n c o n e l ( 0 . 1 0 5 mm i n d i a m e t e r ) i s more s e n s i t i v e t h a n c o a r s e - g r a i n e d I n c o n e l ( 0 . 2 5 0 mm i n diameter) t o the several test environments.

Table 11.4 t a b u l a t e s the comparative responses t o these environments a t a r e p r e s e n t a t i v e stress level.

E f f e c t o f Environment on S t r a i n v s . for Inconel.

A fineg r a i n e d specimen i s b e i n g t e s t e d t h a t was r u n i n a r g o n f o r t h e f i r s t 1 6 0 h r and then a l t e r n a t e l y i n hydrogen and argon atmospheres.

Each atmosphere was m a i n t a i n e d f o r a b o u t 100 hours.

When t h e h y d r o g e n was i n t r o d u c e d , t h e s t r a i n r a t e was a c c e l e r a t e d ; a n d w h e n t h e a r g o n was r e - i n t r o d u c e d , t h e c r e e p r a t e d u r i n g t h e argon c y c l e remained a p p r o x i m a t e l y t h e same a s t h e l a s t creep r a t e i n hydrogen. These r e s u l t s appear t o i n d i c a t e t h a t the e f f e c t of t h e hydrogen atmosphere is one of a permanent nature.

Metallographic s t u d i e s do n o t c l e a r l y r e v e a l w h a t t h e e f f e c t i s ; however, t h e m i c r o s t r u c t u r e i n d i c a t e s t h e p o s s i b l e removal or T i m e Curves

147

ANP PROJECT QUARTERLY PROGRESS REPORT

Fine-grained Inconel Tested i n a i r

"2500

Coarse-grained Inconel "2500

Peened and t e s t e d i n a r g o n

835

Tested i n argon

73 0

P r e o x i d i z e d and t e s t e d i n a r g o n

730

T e s t e d i n mol t e n NaF-ZrF,-UF, (46-50-4mole X)

415

470

T e s t e d i n hydrogen

2 50

600

s o l u t i o n o f c a r b i d e s a n d o x i d e s and a much m o r e f r e a u e n t i n c i d e n c e o f i n t e r g r a n u l a r c r a c k i n g when t h e t e s t s a r e conducted i n a hydrogen atmosphere.

The s t r a i n v s . time r e l a t i o n s h i p s of fine-grained Inconel t e s t e d i n the s e v e r a l e n v i r o n m e n t s a t 815째C and s t r e s s e d t o 3500 p s i a r e shown i n F i g . 1 1 . 6 . The r e s u l t s a r e r e p r e s e n t a t i v e of s e v e r a l t e s t s i n each environment. The a b s e n c e o f a l i n e a r , s e c o n d s t a g e s e c t i o n i n the s t r a i n vs. time curves might i n d i c a t e t h a t t h e i n t e r granular cracking characteristic of high-temperature f a i l u r e i s i n i t i a t e d very early i n the test l i f e .

The v a r i o u s t e s t c o n d i t i o n s may e i t h e r h a s t e n o r r e t a r d t h e f o r m a t i o n and p r o p o g a t i on o f t h e s e i n t e r g r a n u l a r c r a c k s and, hence, a l t e r t h e creeprupture properties.

The program o f t e s t i n g i n m o l t e n fluoride mixtures continues, but the < - c u r a c y o f t h e r e s u l t s i s c l o u d e d by t e m p e r a t u r e c o n t r o l d i f f i c u l t i e s and by t h e e f f e c t s o f t h e d e s c a l i n g procedure.

The f i r s t s e r i e s o f t e s t s w a s p r e c e d e d by a s o d i u m d e s c a l i n g operation.

T h e r u p t u r e t i m e s were v e r y s h o r t , and t h e m i c r o s t r u c t u r e s indicate a stress-corrosion type of failure.

S u b s e q u e n t t e s t s were p r e c e d e d by a f l u o r i d e d e s c a l i n g p r o c e s s .

The r u p t u r e t i m e s were c l o s e r t o t h o s e o b s e r v e d i n a r g o n , and t h e m i c r o structures revealed subsurface voids

148

500

or hole

formation and very l i t t l e i n t e r g r a n u l a r c r a c k i n g . Only o n e t e s t of coarse-grained Inconel i n f l u o r i d e s showed a l o n g e r r u p t u - e l i f e t h a n t h e b e s t l i f e observed f o r the fine-grained s p e c i m e n s a t t h e same s t r e s s , Type 316 S t a i n l e s s S t e e l Tube Burst T e s t s i n Argon. T h e t u b e - b u r s t t e s t s r u n t o d a t e w e r e f o r t y p e 316 s t a i n l e s s steel tubes loaded i n t e r n a l l y with argon under p r e s s u r e and h e l d i n an a t m o s p h e r e o f p u r e a r g o n . A s p e c i men s o l o a d e d h a s a m u l t i a x i a l s t r e s s s y s t e m , and t h e r e s u l t s i n d i c a t e t h a t t h e test l i f e under these conditions w i l l be much l e s s t h a n t h a t f o u n d f o r t h e same m a t e r i a l s t r e s s e d i n t e n s i o n o n l y a t a s t r e s s e q u a l t o t h e maximum s t r e s s imposed on t h e t u b e .

FABRICATION OF CONTROL A N D SAFETY RODS

E . S. Bomar J . H. Coobs

H. Inouye R. W. Johnson

Metallurgy Division A . Levy P r a t t and Whitney A i r c r a f t D i v i s i o n

Control Rods f o r the G - E R-1 Reactor.

A study concerning the adaptation of t h e i r o n - c e m e n t e d b o r o n c a r b i d e compos i t i o n u s e d f o r t h e ARE s a f e t y r o d s l u g s t o t h e c o n t r o l r o d s f o r t h e G-E R - 1 r e a c t o r was u n d e r t a k e n a t t h e r e q u e s t o f t h e G e n e r a l E l e c t r i c Co. In b r i e f , the specifications f o r these

PERIOD ENDING MARCH 10, 1953 previous progress report(3) included some r e s u l t s o f t e s t s c o n d u c t e d i n a r g o n p u r i f i e d by t i t a n i u m s p o n g e .

The work d u r i n g t h i s p e r i o d h a s i n c l u d e d 1 0 0 - h r t e s t s i n vacuum a t 8 0 0 and 1000°C. T h i s work w i l l a l s o indicate the pressures tolerable i n subsequent h e a t treatments.

The d a t a obtained thus f a r a r e given i n Table 11.6.

F u t u r e work i s t o i n c l u d e t h e e f f e c t of r e c i r c u l a t i n g the p u r i f i e d gas over t i t a n i u m sponge and d r y i n g a g e n t s by u s i n g a pump i n a c l o s e d system.

Oxidation.

T e s t s h a v e b e e n comp l e t e d on t h e o x i d a t i o n o f c o l u m b i u m i n a i r c o n t a i n i n g 1 8 . 7 mm w a t e r v a p o r .

This investigation w a s undertaken a f t e r a r u n made a t 4 0 0 ° C i n a i r t h a t i n a d v e r t e n t l y c o n t a i n e d water vapor resulted in a particularly rapid rate of oxidation.

A c o n s t a n t h u m i d i t y was o b t a i n e d hy p a s s i n g t h e a i r t h r o u g h a s a t u r a t e d s o l u t i o n o f NH,C1 a t 25°C; t h e m o i s t u r e c o n t e n t checked t o w i t h i n 0.5% o f t h e s a t u r a t i o n v a l u e when t h e w a t e r a b s o r b e d i n a n h y d r o n e was weighed.

The r e s u l t s a t 400°C have been c h e c k e d , arid t h e y show t h a t t h e p r e s e n c e of moisture increases the oxidation r a t e by a f a c t o r o f a b o u t 400 a t t h e end o f 1 0 h o u r s .

A t 600°C, a r e v e r s e e f f e c t was found i n t h a t t h e o x i d a t i o n

r a t e decreased s i g n i f i c a n t l y (by a f a c t o r of 2 ) .

I t was a l s o a p p a r e n t t h a t t h e o x i d a t i o n r a t e was n o t l i n e a r .

S e v e r a l b r e a k s i n t h e c u r v e of a p l o t o f w e i g h t g a i n vs. time have been observed and d u p l i c a t e d .

A t 800, 1 0 0 0 , a n d 12OO0C, t h e o x i d a t i o n r a t e s i n m o i s t a i r a r e no d i f f e r e n t from those i n dry a i r .

X-ray d a t a have been o b t a i n e d f o r t h e specimens o x i d i z e d i n a i r ; and t h u s f a r t h e o x i d e s formed a r e a l l m o d i f i c a t i o n s of Cb,O,, o f w h i c h t h e r e are three.(4) I n c o n s i s t e n c i e s have been o b s e r v e d f o r t h e o x i d a t i o n r a t e s a t 800°C. I n t h e s e runs, f l a t s h e e t o x i d i z e d t o a w h i t e s c a l e on t h e edges, b u t t h e o t h e r a r e a s formed a r a t h e r dense black oxide. A 0.040-in. w i r e became e n t i r e l y w h i t e w i t h o x i d e .

Above 800"C, t h e o x i d a t i o n r a t e showed a s l i g h t d e v i a t i o n from l i n e a r i t y .

T h i s may h a v e b e e n t h e r e s u l t o f p a r t i a l protection of the underlying m e t a l by t h e t h i c k o x i d e or a d e c r e a s e i n the surface area.

The r e s u l t s a t 8 0 0 , 1 0 0 0 , a n d 1200°C a r e b e i n g c h e c k e d by o x i d i z i n g c o l u m b i u m r o d t h a t i s c l a d o n the circumference with Inconel.

I t i s hoped t h a t t h e i n c o n s i s t e n c i e s o b s e r v e d a t 800°C c a n be e l i m i n a t e d by t h i s method,since it is believed t h a t t h e i n c o n s i s t e n c i e s were c a u s e d by t h e surface areas n o t being constant.

(3)E. S. Bomar a n d H. I n o u y e , ANP Q u a r . P r o g .

R e p . D e c . 1 0 , 1952, ORNL-1439. p . 157.

1-21 (1941).

TABLE 1 1 . 6 . =

B r a u e r , 2. a n o r g .

u.

allgen.

c h c a , 248,

RESULTS OF 100-hr TESTS OF COLUMBIUM IN VACUUM

I

TEMPERATURE:

("C)

(4)G.

HARDNESS MANGE VPN (10-kg l o a d )

REMARKS Brittle, slightly tarnished

-

800

.

1000

1.0

+O. 0046

+271

0.1

+O. 0006

+22

Bright

0.01

-0.0002

-1 6

Bright

0.1

+O. 00051

+ 17

S1 i g h t l y t a r n i s h e d

0.05

+O. 00037

+9

S1 i g h t l y t a r n i s h e d

0.01

0.00005

-40

Bright

-

151

ANP PROJECT QUARTERLY PROGRESS REPORT F A B R I C A T I O N OF METALS

E . S . Bomar, J r .

J . H . Coobs

H. Inouye R . W. J o h n s o n

Metallurgy Division

A. Levy P r a t t and Whitney A i r c r a f t D i v i s i o n

-

H i g h C o n d u c t i v i t y Me t a l s f o r Radiator Fins.

A program h a s been outlined f o r the evaluation of coated m e t a l s s u i t a b l e f o r r a d i a t o r f i n mat e r i a l s , methods o f a s s e m b l y , and e f f e c t s of exposure t o h i g h temperatures.

The c o a t e d m e t a l s must have good t h e r m a l c o n d u c t i v i t y , a s w e l l a s the required high- temperature corrosion resistance.

The m a t e r i a l s r e q u i r e d f o r t h i s work h a v e b e e n o r d e r e d , a n d t h e d e t a i l e d e x p e r i m e n t a l work m u s t await t h e i r a r r i v a l .

Small q u a n t i t i e s of m a t e r i a l s s i m i l a r t o t h o s e on o r d e r h a v e b e e n prepared and submitted t o t h e Welding Group f o r e v a l u a t i o n o f b r a z i n g t e c h niques.

These materials include c h r o m i u m - p l a t e d c o p p e r , I n c o n e l - and type 310 s t a i n l e s s - s t e e l - c l a d copper, and I n c o n e l - and t y p e 310 s t a i n l e s s steel-clad silver.

O x y g e n f r e e , h i g h c o n du c t i v i t y copper chromium-plated t o various t h i c k n e s s e s was t e s t e d i n f l o w i n g a i r a t 815째C f o r times up t o 30 h o u r s .

It was f o u n d t h a t t h e chromium o x i d e formed on t h e s u r f a c e s p a l l e d a n d d i d n o t form a p r o t e c t i v e f i l m . T h u s , t h e p o s s i b i l i t y o f u s i n g chromium-plated copper f o r high-conductivity f i n s is n o t very promising.

S o l i d - P h a s e Bonding.

Two s e r i e s o f s a m p l e s o f s o l i d - p h a s e bonded m e t a l s have been p r e p a r e d and a r e t o be studied.

One s e r i e s o f s a m p l e s w i l l be u s e d f o r e v a l u a t i n g t h e e f f e c t o f t i m e on t h e e x t e n t o f b o n d i n g ; t h e o t h e r s e t w i l l be u s e d f o r m e a s u r i n g the effectiveness of electrodeposited chromium i n b o n d i n g molybdenum t o other metals, Chromium w a s s e l e c t e d a s a t r i a l b o n d i n g medium b e c a u s e o f i t s u n l i m i t e d s o l u b i l i t y w i t h molybdenum.

-

152

-

R u n s h a v e b e e n made w i t h c h r o m i u m p l a t e d molybdenum v s . n i c k e l , i r o n , s t a i n l e s s s t e e l , a n d I n c o n e l a t 1150 a n d 125OOC. One r u n h a s b e e n made t o c h e c k t h e s e l f - w e l d i n g o f molybdenum a t 1500째C. E x t r u s i o n of High-Purity Tubing.

T h i s phase o f development is a r e s u l t o f t h e p r e s e n t need f o r h i g h - p u r i t y I n c o n e l t u b i n g - and s u b s e q u e n t l y f o r other high-temperature alloys - f o r corrosion t e s t i n g t o determine the e f f e c t o f i m p u r i t i e s on c o r r o s i o n resistance.

The p r i m a r y p r o b l e m t o d a t e i n t h e e x t r u s i o n p r o c e s s h a s been o n e o f l u b r i c a t i o n , a s e v i d e n c e d by s e v e r a l a t t e m p t s t o produce t h e Inconel tubing.

None o f t h e e x t r u s i o n s h a s been e n t i r e l y s u c c e s s f u l , b e c a u s e e i t h e r t h e mandrel broke or t h e t u b e ruptured.

M o l t e n g l a s s was s e l e c t e d a s t h e lubricant for the extrusion process , which i s a m o d i f i c a t i o n o f S e j o u r n e t Ugine process , because t h e u n i t e x t r u s i o n p r e s s u r e s r e q u i r e d a r e lower w i t h g l a s s than w i t h g r a p h i t e or o i l .

Another f a c t o r f a v o r i n g molten g l a s s i s the reduced p o s s i b i l i t y o f pickup of carbon and s u l f u r .

As an i l l u s t r a t i o n , a s o l i d r o d was e x t r u d e d s u c c e s s f u l l y by u s i n g N e c r o l i n e , which h a s a g r a p h i t e b a s e , and a n a l y s i s i n d i c a t e d an i n c r e a s e i n c a r b o n a n d s u l f u r from c a s e t o e x t r u d e d f o r m , a s follows: 0.01% c a r b o n a s c a s t , 0.03% c a r b o n e x t r u d e d ; 0.007% s u l f u r a s c a s t , 0.011% s u l f u r e x t r u d e d .

For t h e e x t r u s i o n s made t h u s f a r , t h e e x t r u s i o n b i l l e t was h e a t e d i n molten lead g l a s s .

Unfortunately, a p o r t i o n o f t h e l e a d compound p r e s e n t i n t h e g l a s s was r e d u c e d , a n d a s a r e s u l t metallic lead precipitated i n the bath.

The mechanism o f t h e r e d u c t i o n i s n o t y e t known; h o w e v e r , t h e g l a s s was h e l d i n a s t a i n l e s s s t e e l c o n t a i n e r t h a t was s e a t e d i n a n d extended above t h e t o p o f a g a s - f i r e d p o t f u r n a c e . The p r e s c r i b e d e x t r u s i o n t e m p e r a t u r e f o r I n c o n e l i s 2300"F, b u t with the present h e a t i n g arrangement,

r i

PERIOD ENDING MARCH 10, 1953 2 1 0 0 째 F i s ; t h e maximum t e m p e r a t u r e o b t a i n a b l e . These f a c t o r s , no doubt, c o n t r i b u t e d t o or c a u s e d t h e e x t r u s i o n failures.

One o f t h e u l t i m a t e o b j e c t i v e s i s t o obtain tubing t h a t has no i n c l u s i o n s r e s u l t i n g from t h e a d d i t i o n of mall e a b i l i z i n g e l e m e n t s s u c h a s magnesium, t i t a n i u m , m a n g a n e s e , and aluminum.

To d e t e r m i n e which ma 11e a b i 1 i z i n g e l e m e n t s a r e n e c e s s a r y , i n g o t s were vacuum c a s t w i t h (1) no m a l l e a b i l i z i n g e l e m e n t s , ( 2 ) 0.05% magnesium ( n o m i n a l ) , a n d ( 3 ) 0.25% t i t a n i u m , a s a Ti-Al-Mn m a s t e r a l l o y , and 0.05% magnesium.

D i f f i c u l t y was e x p e r i e n c e d i n a t t e m p t i n g t o a d d magnesium i n t h e form o f a master a l l o y t o I n c o n e l melts under vacuum b e c a u s e o f t h e h i g h v a p o r p r e s s u r e o f magnesium.

T h e s e i n g o t s were s u c c e s s f u l l y e x t r u d e d by u s i n g r o c k wool i n s u l a t i o n i n t h e p r e s s c o n t a i n e r a n d g l a s s wool ( b o t h p y r e x and s o f t g l a s s ) on t h e h o t extrusion billet.

This procedure is e s s e n t i a l l y t h e same a s t h a t e m p l o y e d by t h e I n t e r n a t i o n a l N i c k e l C o , The e x t r u s i o n c o n d i t i o n s were: Temperature 2225째F

Die

45"V

E x t r u s i o n time Extrusion pressure Extrusion r a t i o S u r f a c e s 1i gh t l y r o u g h e n e d

1 to 3 sec -50 t s i 13.7

RUN NO.

A d d i t i o n a l work i s t o i n c l u d e t h e extrusion of Inconel tubing under s i m i l a r c o n d i t i o n s and t h e e x t r u s i o n of the a u s t e n i t i c s t a i n l e s s steels, s u c h a s t y p e 310 s t a i n l e s s s t e e l .

F u t u r e m e l t s w i l l be made i n z i r c o n i a c r u c i b l e s t o e l i m i n a t e magnesium pickup.

HOT-PRESSED PUMP SEALS

E. S . Bomar, J r .

J . H. Coobs R. W . J o h n s o n Metallurgy Division A. Levy P r a t t and W h i t n e y A i r c r a f t D i v i s i o n

A series of exploratory runs has been made o n m a t e r i a l s b e i n g c o n s i d e r e d for test seal rings.

The r i n g s a r e t o b e c o m p o s e d o f Ag, Cu, 95% Ag-5% Cu a l l o y , o r 18-8 s t a i n l e s s s t e e l w i t h 1 4 v o l % MoS,.

T e s t specimens 1/2 i n . i n d i a m e t e r a n d 3 / 8 i n . l o n g were p r e p a r e d by h o t p r e s s i n g a t 2 5 0 0 p s i in a graphite die, with the results shown i n T a b l e 1 1 . 7 .

T h e f i r s t r u n s on t h e c o p p e r , s i l v e r , a n d Ag-Cu a l l o y c o m p o s i t i o n s w i t h MoS, d e m o n s t r a t e d t h a t t h e s e m a t e r i a l s may be r e a d i l y f a b r i c a t e d by h o t p r e s s i n g . Run 5 shows t h e b e h a v i o r o f a c o a r s e g r a d e o f s i l v e r (-60 t 1 0 0 m e s h ) , w h i c h i s on h a n d i n q u a n t i t y .

Run 6 s h o w s t h a t t h i s c o a r s e p o w d e r

MATERIAL

TEMPERATURE PRESSING

("C)

DENSITY ( A theoretical)

1

FU

("C" g r a d e )

760

92.8

2

Cu YCJ' g r a d e )

910

95.3

3

Ag ( p r e c i p i t a t e d )

65 5

95.7

4 5

95% Ag ( p p t . 1-596 Cu (,,CJJg r a d e )

830

95.2

Ag (-60 t 100 mesh)

930

94.0

6

18-8 s t a i n l e s s steel'

1010

78.0

153

ANP PROJECT QUARTERLY PROGRESS REPORT may be s a t i s f a c t o r y b u t t h a t i t i s somewhat more d i f f i c u l t t o c o n s o l i d a t e .

An i n i t i a l run made w i t h t h e s t a i n l e s s steel-MoS, composition d i d n o t consolidate sufficiently.

F u r t h e r runs a r e p l a n n e d a t somewhat h i g h t e m p e r a t u r e s , w i t h molybdenum o r A 1 , 0 , u s e d a s d i e l i n e r s i f necessary.

CERAMICS

L. M. Doney S. D. F u l k e r s o n

J . R. J o h n s o n A. J . T a y l o r

G. D. W h i t e Metallurgy Division Ceramic coatings f o r Shielding.

A

l e a d b o r a t e e n a m e l w a s a p p l i e d by f l a m e - s p r a y i n g t o a 5 - f t by 5 - f t by 7/%-in. steel p l a t e , but t h e coating was i m p e r f e c t on p a r t o f t h e s u r f a c e .

The t h i c k n e s s o f t h e p l a t e p r e v e n t s t h e s p r a y i n g o f a smooth, g l a s s c o a t i n g , e v e n when t h e p l a t e i s i n i t i a l l y p r e h e a t e d t o 1000°F. A l a r g e r flames p r a y u n i t would p r o b a b l y work, b u t w i t h t h e a v a i l a b l e u n i t , a maximum s t e e l t h i c k n e s s o f a b o u t 1/8 i n . i s indicated, T h e c o a t i n g c a n be s u c c e s s f u l l y a p p l i e d by t h e s t a n d a r d e n a m e l i n g t e c h n i q u e o f d u s t i n g t h e powdered g l a s s on t h e r e d h o t m e t a l .

An i n i t i a l m e t a l t e m p e r a t u r e o f 1400’F i s a d e q u a t e for t h i s c o a t i n g .

Development of Cermet Fuel Elements.

A Cr-A1203 s o l i d f u e l element of p ~ s s i b l eu s e i n n u c l e a r - p o w e r e d a i r c r a f t h a s been f a b r i c a t e d .

These c e r m e t e l e m e n t s would be f o r u s e i n a r e a c t o r system t h a t resembled a d i s k heat exchanger, D i s k s o f Cr-A12.0, c o n t a i n i n g an e n c l o s e d “ s a n d w i c h ” r i n g o f UO, a r e s t r u n g on 1 / 4 - i n . - d i a s t a i n l e s s s t e e 1 t u b e s t h r o u g h which a c o o l a n t passes, These d i s k s give up t h e i r h e a t t o an a i r stream p a s s i n g over t h e i r surfaces, The c o o l a n t keeps t h e s t e e l t u b e s c o o l enough t o maintain adequate strength, resist o x i d a t i o n , and p r o v i d e some m o d e r a t i o n i n the r e a c t o r core.

154

The Cr-A1,0, c e r m e t h a s e x c e l l e n t o x i d a t i o n r e s i s t a n c e u p t o 2200’F and adequate heat-shock r e s i s t a n c e i n the form p r o p o s e d .

However, r a d i a t i o n damage and f i s s i o n p r o d u c t r e t e n t i o n a r e unknown.

The d i s k s have been fabricated with a 0.020-in. thickness and a 1 - i n . o u t s i d e d i a m e t e r .

A photomicrograph o f a Cr-A1203 d i s k s e c t i o n c o n t a i n i n g 8 w t 76 UO, i s shown i n Fig. 11.7.

A silicon-silicon carbide material h a s been proposed a s a p o t e n t i a l l y useful solid a i r c r a f t reactor fuel e l e m e n t , and e x p e r i m e n t s h a v e been c a r r i e d out t o f a b r i c a t e such elements.

A p r o c e s s s i m i l a r t o t h a t d e v e l o p e d by t h e C a r b o r u n d u m Co. f o r i m p r e g n a t i n g carbon i s used.

Cross-shaped elements

Fig. 11.7.

S e c t i o n o f Cr-A1,0, Cermet Disk Containing 8 wt % UO,.

PERIOD ENDING MARCH 1 0 , 1 9 5 3 have been f a b r i c a t e d and a r e b e i n g tested to obtain physical property measurements. R a d i a t i o n damage s t u d i e s and s i m u l a t e d r e a c t o r s e r v i c e t e s t s have been o u t l i n e d .

R e d u c t i o n of the P o r o s i t y o f A R E Beryllium Oxide. A s e r i e s o f e x p e r i m e n t s was i n i t i a t e d i n a n a t t e m p t t o reduce t h e p o r o s i t y and t o i n c r e a s e the corrosion resistance of the hexagonal beryllium oxide blocks t h a t a r e t o b e u s e d f o r t h e ARE. I m p r e g n a t i o n o f porous b e r y l l i u m o x i d e t e s t p i e c e s w i t h v a r i o u s m a t e r i a l s was a t t e m p t e d , and p r e l i m i n a r y vapor d e p o s i t i o n s t u d i e s were begun.

Samples of t h e impregnated b e r y l l i u m and t h e o t h e r s p e c i m e n s w i l l be s u b j e c t e d t o c o r r o s i o n t e s t s i n sodium, In the f i r s t impregnation, the b e r y l l i u m o x i d e t e s t p i e c e s ( 1 / 2 by 1/4 b y 1 / 4 i n . ) w e r e i m m e r s e d i n molten hydrated beryllium n i t r a t e a t 135°C f o r 4 8 h o u r s , The t e s t p i e c e s were t h e n p l a c e d i n a s m a l l p o r c e l a i n c r u c i b l e , covered with t h e beryllium n i t r a t e , and h e a t e d u n t i l e v o l u t i o n o f NO, w a s c o m p l e t e .

Then, a f t e r t h e powdered b e r y l l i u m o x i d e had been 0 s c r a p e d from t h e s u r f a c e s , t h e t e s t p i e c e s were h e a t e d t o 1550"C, h e l d f o r 1 5 min, and a l l o w e d t o c o o l t o room temperature.

This procedure caused a s l i g h t permanent i n c r e a s e i n t h e w e i g h t of t h e test p i e c e s but no measurable reduction i n porosity.

The s e c o n d i m p r e g n a t i o n e x p e r i m e n t was c a r r i e d o u t u n d e r s i m i l a r c o n d i t i o n s , b u t magnesium n i t r a t e was used instead of beryllium n i t r a t e .

This impregnation resulted i n an a p p r e c i a b l e p e r m a n e n t w e i g h t g a i n and i n a reduction of the porosity t o a b o u t 35% of i t s o r i g i n a l v a l u e , The t h i r d method t r i e d w a s s u c c e s s f u l i n reducing the porosity of the t e s t p i e c e s t o an a l m o s t n e g l i g i b l e amount.

I n t h i s method, a m i x t u r e o f 37.5% A l F , a n d 6 2 . 5 % CaF, was p r e f u s e d t o give a glass.

The g l a s s was t h e n p u l v e r i z e d and s u s p e n d e d i n w a t e r t o g i v e a very heavy s u s p e n s i o n .

The

s m a l l ( 1 / 2 by 1 / 4 by 1 / 4 i n . ) b e r y l l i u m o x i d e t e s t p i e c e s were d i p p e d i n t o t h i s s u s p e n s i o n a n d d r a i n e d , aind t h e a d h e r i n g c o a t i n g was d r i e d .

These p i e c e s were t h e n h e a t e d t o 1550"C, h e l d f o r 1 5 min a t t h i s t e m p e r a t u r e , and a l l o w e d t o c o o l i n t h e f u r n a c e .

This treatment r e s u l t e d i n the coating s o a k i n g i n t o t h e porous p i e c e s and completely f i l l i n g the pores.

A t e s t was p e r f o r m e d t o d e t e r m i n e w h e t h e r t h e method o u t l i n e d a b o v e f o r t h e A1F,-CaF2 m i x t u r e would be f e a s i b l e when u s e d on o n e o f t h e A R E - s i z e blocks.

One o f t h e h a l f - b l o c k s o f b e r y l l i u m o x i d e , which had been shown t o be p o r o u s by b o t h i m m e r s i o n i n a f u s c h i n - d y e - a l c o h o l s o l u t i o n a n d by t h e w a t e r a b s o r p t i o n method, was c o a t e d w i t h t h e AlF,-CaF2 m i x t u r e .

T h e c o a t e d b l o c k was t h e n h e a t e d a t 750°C p e r h o u r t o 1550°C, h e l d a t 1550°C f o r a b o u t 4 5 m i n , and c o o l e d o v e r n i g h t i n t h e f u r n a c e . The r e s u l t was a nonporous b l o c k , e x c e p t f o r cracks t h a t , although p r e s e n t i n t h e b l o c k b e f o r e t h e h e a t t r e a t m e n t , were now much e n l a r g e d , To d e t e r m i n e t h e c a u s e f o r t h e enlargement of the c r a c k s , two, f u l l s i z e , hexagonal blocks of beryllium o x i d e were h e a t e d a t 750°C p e r h o u r t o 1550°C and h e l d f o r 1 h o u r .

These b l o c k s had no a p p l i e d c o a t i n g , and h e n c e a n y e f f e c t s c o u l d be a t t r i b u t e d to the heat treatment.

T h e r e were s e v e r a l m i n u t e c r a c k s a n d a 2.one o f weakness p e r p e n d i c u l a r t o t h e a x i s a c r o s s t h e middle o f each block before t h e h e a t t r e a t m e n t was c a r r i e d o u t .

However, t h e s e b l o c k s a r e t y p i c a l n e a r l y a l l b l o c k s on h a n d h a v e t h i s zone o f weakness.

After the heat t r e a t m e n t , b o t h b l o c k s had broken a l o n g t h e zone o f weakness, and one h a d a l s o s p l i t a x i a l l y from o n e s i d e into the core hole.

I t i s t o be concluded t h e r e f o r e t h a t the block c a n be b r o k e n by h e a t i n g a t 750°C p e r h o u r and t h a t t h e i m p r e g n a t i o n t r e a t ment i s n o t t h e c a u s e o f t h e c r a c k i n g of the pieces.

-

155

12.

HEAT TRANSFER AND PHYSICAL PROPERTIES H. F. Poppendiek -Reactor Experimental Engineering D i v i s i o n

Some p r e l i m i n a r y t h e r m a l c o n d u c t i v i t y m e a s u r e m e n t s on m o l t e n s o d i u m h y d r o x i d e were made, and r e s u l t s indicate that the conductivity inc r e a s e s from a b o u t 0.4 t o a b o u t 0.8 Btu/hr.ft*"F over the temperature r a n g e of 650 t o 1000째F. The e n t h a l p i e s and h e a t c a p a c i t i e s of s t r o n t i u m h y d r o x i d e a n d NaF-ZrF,-UF, (50-46-4 mole %) h a v e b e e n o b t a i n e d .

The h e a t c a p a c i t y o f s t r o n t i u m h y d r o x i d e was found t o be 0.32 k 0.03 c a l / g o o C o v e r t h e t e m p e r a t u r e r a n g e o f 570 t o 900째C; t h e -+'&at c a p a c i t y o f N a F - Z r F 4 - U F , ( 5 0 - 4 6 - 4 m o l e %) was f o u n d t o b e 0.31 k 0.03 c a l / g ' " C over t h e temperat u r e r a n g e o f 5 5 0 t o 850OC. Some p r e l i m i n a r y v i s c o s i t y m e a s u r e m e n t s on m o l t e n sodium h y d r o x i d e were made t h a t v a r i e d from 4 . 6 c p a t 34OoC t o 2 . 5 cp a t 448째C. Vapor p r e s s u r e m e a s u r e m e n t s made on t h e e n r i c h e d ARE f u e l w e r e much l o w e r t h a n t h e t h e o r e t i c a l v a l u e determined f o r t h e pure components (NaF, Z r F , , and UF,), w h i c h i n d i c a t e s t h e e x i s t e n c e of complex compounding of i o n s a t h i g h t e m p e r a t u r e s .

A graph of t h e t e m p e r a t u r e v a r i a t i o n of t h e P r a n d t l moduli of s e v e r a l f l u o r i d e m i x t u r e s , a s w e l l a s some l i q u i d m e t a l s , w a t e r , a i r , and sodium h y d r o x i d e , has been prepared; the P r a n d t l moduli of t h e f l u o r i d e mixtures a r e b e t w e e n a p p r o x i m a t e l y 1 and 10 i n t h e h i g h - t e m p e r a t u r e r a n g e i n which a i r c r a f t reactors are t o operate.

An a n a l y s i s h a s b e e n c o m p l e t e d t h a t c a n be used t o minimize t h e w e i g h t of a r a d i a t o r f o r a g i v e n power o u t p u t by o p t i m i z i n g t h e f i n s p a c i n g , f i n t h i c k n e s s t u b e d i a m e t e r , and t u b e plate-fin radiators he laminar flow r e g i o n .

An a p p a r a t u s h a s b e e n d e s i g n e d f o r determining f l u i d velocity p r o f i l e s i n t h e a n n u l a r s p a c e s found i n r e a c t o r systems.

Temperature d i s t r i b u t i o n s

i n thermal entrance regions of c i r culating fuel reactor systems are b e i n g d e t e r m i n e d m a t h e m a t i c a l l y by t h e f i n i t e d i f f e r e n c e method.

An apparatus for experimental study of t h e thermal s t r u c t u r e i n a c i r c u l a t i n g f u e l s y s t e m s i m i l a r t o t h e ARiE c o n f i g u r a t i o n h a s been a s s e m b l e d .

THERMAL C O N D U C T I V I T Y OF L I Q I J I D S

W. D. Powers S. J . C l a i b o r n e R. M. B u r n e t t Reactor Experimental Engineering Division T h r e e d i f f e r e n t m e t h o d s a r e now b e i n g used t o d e t e r m i n e t h e t h e r m a l c o n d u c t i v i t y o f l i q u i d s a t high temperatures.

Two m e t h o d s a r e b a s e d o n s t e a d y - s t a t e f l o w of h e a t d o w n w a r d t h r o u g h a t h i n s e c t i o n of l i q u i d , and t h e t h i r d method i n v o l v e s t r a , n s i e n t h e a t f l o w from an e l e c t r i c a l l y h e a t e d tube t o the surrounding t e s t l i q u i d .

These methods have been descritbed i n previous quarterly reports.

At present, the thermal conductivity of molten sodium hydroxide is being determined.

Preliminary results i n d i c a t e t h a t t h e c o n d u c t i v i t y of sodium h y d r o x i d e i n c r e a s e s f r o m a b o u t 0.4 t o about 0.8 B t u / h r * f t * " F over t h e t e m p e r a t u r e r a n g e o f 650 t o 1000 O F .

A f t e r a d d i t i o n a l t h e r m a l conduct i v i t y m e a s u r e m e n t s o n sodium h y d r o x i d e h a v e b e e n c o m p l e t e d , some of t h e o t h e r h y d r o x i d e s w i l l be i n v e s t i g a t e d .

HEAT C A P A C I T Y OF L I Q U I D S

W . D. Powers G. C. B l a l o c k Reactor Experimental Engineering Division The e n t h a l p y and t h e h e a t c i a p a c i t y o f s t r o n t i u m h y d r o x i d e a n d NaF-ZrF,-UF, ( 5 0 - 4 6 - 4 mole %) h a v e b e e n d e t e r m i n e d 157

A N P PROJECT QUARTERLY PROGRESS REPORT w i t h Bunsen i c e c a l o r i m e t e r s : for strontium hydroxide over t h e temperat u r e r a n g e 570 t o 9 0 0 " C , ( ' )

HT ( l i q u i d )

- HOoC

c

=

P

T

-

19

,

0.32 f 0.03

;

( s o l i d ) = 0.32

f o r ARE f u e l m i x t u r e N a F - Z r F 4 - U F , ( 5 0 - 4 6 - 4 mole X) o v e r t h e t e m p e r a t u r e r a n g e 550 t o 8 5 0 째 C , ( 2 ) HT ( l i q u i d )

- HOoC

( s o l i d ) = 0.31 T c

P

=

-

9

where H i s t h e e n t h a l p y i n c a l / g , T i s t h e t e m p e r a t u r e i n " C , and c is P the heat capacity i n cal/g*"C. Shown i n F i g . 1 2 . 1 a r e a f e w of t h e many e n t h a l p y - t e m p e r a t u r e p o i n t s f o r t h e ARE f u e l m i x t u r e t h a t w e r e u s e d t o e s t a b l i s h t h e above e n t h a l p y and h e a t c a p a c i t y r e l a t i o n s h i p s .

r

VISCOSITY AND DENSITY OF ALKALI HYDROXIDES

,

0.31 f 0.03,

( l ) W . D. Powers and G. C. B l a l o c k , B e a t C a p a c i t y of S t r o n t i u m H y d r o x i d e , O W L CF-53-2-84 (Feb. 9.

1953).

(2)W. D. Powers and G. C. B l a l o c k . H e a t C a p a c i t y o f F u s e d S a l t M i x t u r e N o . 3 0 , ORNL C F - 5 3 - 2 - 5 6 (Feb. 6, 1953).

R. F. Redmond S. I . Cohen T. N. J o n e s Reactor Experimental Engineering Division

A preliminary s t u d y o f t h e viscosity o f sodium h y d r o x i d e was made by u s i n g 8c96etDWG. 48661

200

240

200

c

\" -

160

0

Y

>

a -J a

5

I I8 120

I

I

W z

I-MELTING

POINT

0 /J

00

d

-

520OC

-@a-

40

0 400

500

600

700

800

900

TEMPERATURE ("C)

Fig. 12.1. mole %).

158

Enthalpy vs. Temperature for Fluoride Fuel, NaF-ZrF,-uF4

(50-46-4

LJ

PERIOD ENDING MARCH 1 0 , 1 9 5 3 a modified Brookfield viscometer t o check v a l u e s r e p o r t e d i n t h e l i t e r a ture.

The r e s u l t s , w h i c h a g r e e w i t h those i n the l i t e r a t u r e t o within a b o u t lo%, a r e a s f o l l o w s : TEMPERATURE (OC)

VISCOSITY ( c p )

340.3 4.55 399.5 2.95 448.0 2.45 A d r y b o x t h a t w i l l contain f a c i l i t i e s f o r measuring d e n s i t i e s a n d v i s c o s i t i e s h a s b e e n d e s i g n e d and i s b e i n g f a b r i cated.

A new d e v i c e w i l l be employed that relates density to the difference i n pressure required t o bubble gas t h r o u g h o u t l e t s p l a c e d a t two l e v e l s i n t h e material. A horizontal capillary t u b e v i s c o m e t e r i s b e i n g d e s i g n e d and s h o u l d soon be r e a d y f o r c o n s t r u c t i o n .

This device for obtaining absolute m e a s u r e m e n t s w i l l o p e r a t e u n d e r more n e a r l y i s o t h e r m a l c o n d i t i o n s t h a n some of t h e previous viscometers.

VAPOR PRESSURES OF FLUORIDES

R. E . Moore M a t e r i a l s Chemistry D i v i s i o n 1,

Vapor p r e s s u r e s t u d i e s of t h e f l u o r i d e s a l t m i x t u r e s and t h e i r p u r e components o f i n t e r e s t i n c o n n e c t i o n w i t h t h e A i r c r a f t Reactor Experiment were c o n t i n u e d d u r i n g t h e p a s t q u a r t e r .

The m e t h o d a n d a p p a r a t u s o r i g i n a l l y d e s c r i b e d by Rodebush and D i x o n ( 3 ) and discussed i n previous reports(4") were u s e d f o r t h e s e measurements.

The v a p o r p r e s s u r e o f t h e e n r i c h e d f u e l m i x t u r e NaF-ZrF4-UF, ( 5 0 - 2 5 - 2 5 m o l e %) was f o u n d t o i n c r e a s e f r o m 5 t o 6 3 mm Hg o v e r t h e t e m p e r a t u r e r a n g e o f 848 t o 1096째C and i s r e p r e s e n t e d by t h e e q u a t i o n

.

-t 6.844 ( O K ) a t i o n i s 32 k c a l / m o l e

g ) = -6906/T

26, 851 (1925).

d A. L. D i x o n , P h y s . R e v .

(4)R. E . M o o r e and C. J . B a r t o n , ANP Q u a r .

P r o g . R e p . S e p t . 1 0 , 1 9 5 1 , OWL-1154, p. 136. ("R. E. M o o r e , A N P Q u a r . P r o g . R e p . D e c . 1 0 , 1 9 5 1 , OWL-1170, p . 126.

and t h e c a l c u l a t e d b o i l i n g p o i n t i s 1470 "C. I f t h e mixture is regarded a s being c o m p o s e d o f t h e compounds z i r c o n i u m t e t r a f l u o r i d e , uranium t e t r a f l u o r i d e , and sodium f l u o r i d e , t h e i d e a l v a p o r p r e s s u r e a t 970째C, a t e m p e r a t u r e a r b i t r a r i l y c h o s e n for c o m p a r i s o n p u r p o s e s , i s c a l c u l a t e d from R a o u l t ' s law t o be 518 mm Hg. The a c t u a l v a p o r p r e s s u r e of 19 mm i s a v e r y l a r g e n e g a t i v e d e v i a t i o n from i d e a l i t y . T h i s r e s u l t i s i n agreement with r e s u l t s obtained f o r other zirconium t e t r a f l u o r i d e - b e a r i n g m i x t u r e s and h a s b e e n i n t e r p r e t e d a s an i n d i c a t i o n t h a t z i r c o n i u m t e t r a f l u o r i d e and uranium t e t r a f l u o r i d e e x i s t i n thle f u s e d m i x t u r e i n t h e f o r m of c o m p l e x i o n s .

However, i t i s i n t e r e s t i n g t o n o t e t h a t when t h e m i x t u r e i s c o n s i d e r e d t o b e composed of NaZrF' and NaUE:' ( t h e v a p o r p r e s s u r e o f NaUF' a t 97OoC i s n e g l i g i b l e ) , t h e i d e a l pressure is c a l c u l a t e d t o b e 33 mm.

The n e g a t i v e deviation i s s t i l l present, but t o a much l e s s e x t e n t .

It is p o s s i b l e t h a t f u r t h e r complexing of t h e z i r c o n i u m t e t r a f l u o r i d e i s a c c o m p l i s h e d by a d d i n g NaUF5 t o NaZrF'.

I o n s such a s NaZrFi may e x i s t i n t h e s e m e l t s , , P r e l i m i n a r y vapor p r e s s u r e d a t a f o r z i r c o n i u m t e t r a f l u o r i d e and NaF-ZrF4UF, ( 5 0 - 4 6 - 4 mole % ) , t h e c o m p o s i t i o n c h o s e n f o r t h e ARE f u e l , w e r e r e ported previously. (') The vapor pressure e q u a t i o n f o r zirconium tetraf l u o r i d e , o b t a i n e d from t h e l a t e s t d a t a by t h e m e t h o d o f l e a s t s q u a r e s , is l o g P (mm Hg) = -10935.6/T ( O K ) -k 1 2 . 1 1 3 , from w h i c h t h e h e a t o f s u b l i m a t i o n , 50 k c a l / m o l e , a n d t h e s u b l i m a t i o n t e m p e r a t u r e , 912OC, were c a l c u l a t e d .

S i m i l a r l y , t h e d a t a f o r NaF-ZrF,-UF, ( 5 0 - 4 6 - 4 mole %) a r e r e p r e s e n t e d by l o g P (mm Hg) = -7551/T ( O K ) -k 7.888 The h e a t o f v a p o r i z a t i o n , 35 k c a l / r n o l e ,

.

(6)R. E. Moore, ANP Q u a r . P r o g . R e p . S e p t . I o , 1 9 5 2 , OWL-1375, p . 147.

159

ANP PROJECT QUARTERLY PROGRESS REPORT a n d t h e b o i l i n g p o i n t , 1 2 3 5 " C , were c a l c u l a t e d from t h i s e q u a t i o n .

PRANDTL MODULI O F V A R I O U S MATERIALS

The P r a n d t l n u m b e r i s o n e o f t h e important moduli t h a t c h a r a c t e r i z e convective heat t r a n s f e r .

In the case of t u r b u l e n t f l o w , c o n v e c t i v e h e a t t r a n s f e r may b e d i v i d e d i n t o t h r e e c l a s s e s , d e p e n d i n g upon t h e n a t u r e of the fluid: the liquid metals are i n t h e P r a n d t l modulus r a n g e of a b o u t 0.003 t o 0.06; t h e ordinary f l u i d s a r e i n t h e P r a n d t l modulus r a n g e of about 0 . 5 t o a hundred; very v i s c o u s f l u i d s have P r a n d t l numbers of s e v e r a l hundred and above.

Each of t h e s e d i f f e r e n t c l a s s e s of f l u i d s is defined by a d i f f e r e n t t u r b u l e n t c o n v e c t i o n heat t r a n s f e r relationship.

It i s of i n t e r e s t t o n o t e t h e c l a s s i n which the fluoride mixtures f a l l .

Figure 1 2 . 2 p r e s e n t s a graph of P r a n d t l modulus v s . t e m p e r a t u r e f o r t h e l i q u i d m e t a l s , w a t e r , a i r , and sodium h y d r o x ide, as well as for three fluoride mixtures.

In the high-temperature r a n g e i n which a i r c r a f t r e a c t o r s a r e t o o p e r a t e , t h e f l u o r i d e s have P r a n d t l moduli t h a t a r e i n t h e r a n g e o f a p p r o x i m a t e l y 1 t o 10 a n d t h u s s h o u l d h a v e t h e h e a t t r a n s f e r c h a r a c t e r i s t i c s of ordinary fluids.

S P E C I F I C R E A C T O R H E A T T R A N S F E R PROBLEMS

W. S. Farmer Reactor Experimental Engineering D i v i s i on The p r o b l e m o f d e s i g n i n g a minimumweight a i r r a d i a t o r f o r t h e t u r b o j e t e n g i n e s of a nuclear-powered a i r c r a f t hasbeen given f u r t h e r study during the past quarter.

An a n a l y s i s was m a d e ( ' ) which i n v o l v e d m i n i m i z i n g t h e w e i g h t o f a n a i r r a d i a t o r f o r a g i v e n power o u t p u t by o p t i m i z i n g t h e f i n s p a c i n g , f i n t h i c k n e s s , tube diameter, and tube spacing for p l a t e - f i n r a d i a t o r s (7)W. S. F a r m e r , M i n i m u m l e i g h t A n a l y s i s f o r a n A i r R a d i a t o r , ORNL CF-53-1-111 ( t o b e i s s u e d ) .

160

o p e r a t i n g i n t h e laminar flow region.

D i f f i c u l t i e s due t o p o o r b r a z e c o n t a c t between t h e f i n s and t u b e s have r e c e n t l y been e x p e r i e n c e d i n t h e f a b r i c a t i o n of p l a t e - f i n r a d i a t o r s .

Theref ore a t t e n t i o n i s now b e i n g g i v e n t o o t h e r t y p e s of f i n s , s u c h a s c i r c u l a r d i s k f i n s , t h a t c a n be f a b r i c a t e d s o t h a t t h e d i f f i c u l t i e s c a n be o b v i a t e d .

A g e n e r a l a n a l y s i s i s b e i n g made of t h e p e r f o r m a n c e o f r a d i a t o r s t h a t embody s e v e r a l d i f f e r e n t t y p e s of e x t e n d e d s u r f a c e s and s h a p e s .

Because t h e a i r r a d i a t o r i s t o be operated a t high temperatures with large temperature d i f f e r e n c e s e x i s t i n g between t h e w a l l t e m p e r a t u r e and t h e a i r t e m p e r a t u r e , t h e p r o b l e m of noni s o t h e r m a l h e a t t r a n s f e r assumes considerable importance.

Since e f f o r t s t o c o r r e l a t e t h e p e r f o r m a n c e of s e v e r a l a i r r a d i a t o r s t e s t e d by t h e E x p e r i m e n t a l E n g i n e e r i n g Group w i t h e x i s t i n g theories for nonisothermal heat t r a n s f e r have n o t been t o o s u c c e s s f u l , t h e p o s s i b i l i t y o f d e v e l o p i n g new a n a l y t i c a l s o l u t i o n s i s b e i n g examined.

TURBULENT CONVECTION I N ANNULI

J. 0. B r a d f u t e J. I. Lang Reactor Experimental Engineering D i v i s i on A c r i t i c a l review of a l l t h e isothermal velocity distribution data known t o e x i ~ t ( * * ~f o*r ~a n ~ n)u l u s s y s t e m s was c o m p l e t e d , a n d t h e d a t a a r e j u d g e d t o be e i t h e r p a r t l y o r wholly u n s a t i s f a c t o r y because s u f f i c i e n t c a r e i n making t h e d i f f e r e n t e x p e r i m e n t a l m e a s u r e m e n t s was a p p a r ently not exercised.

The n e e d f o r good e x p e r i m e n t a l v e l o c i t y d a t a i n developing mathematical, turbulentflow, h e a t - t r a n s f e r re1a t i o n s f o r ( * ) J . G. K n u d s e n a n d D. L. Katz, P r o c e e d i n g s o f the M i d w e s t e r n C o n f e r e n c e o n F l u i d D y n a m i c s , F i r s t C o n f e r e n c e , May 1 2 - 1 3 , 1 9 5 0 , p. 175. ( 9 ) V . M i k r j u k o v , J . T e c h . P h y s . (U.S.S.R.) 961 (1937). ('"R. R. R o t h f u s , C. C. M o n r a d , a n d B. S e n e c a l , Ind. Eng. Chen. 42, 2511 ( 1 9 5 0 ) .

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161

A N P PROJECT QUARTERLY PROGRESS REPORT a n n u l i ( v i a t h e heat-momentum t r a n s f e r a n a l o g y ) h a s prompted a modest program f o r determining such d a t a .

An a p p a r a t u s h a s b e e n d e s i g n e d (Fig. 12.3) t h a t w i l l c o n s i s t of a 4-in., v e r t i c a l , brass pipe about20 f t l o n g which w i l l be t h e o u t e r a n n u l u s w a l l ; s m a l l e r d i a m e t e r t u b e s which w i l l be t h e i n n e r a n n u l u s w a l l s ; a 6-in., lucite, t e s t section inserted i n the outer pipe; a high-intensity l i g h t source of s h o r t d u r a t i o n ; a c a m e r a ; and an a i r b l o w e r .

As a i r i s pumped t h r o u g h t h e a n n u l u s , p h o t o g r a p h s w i l l be taken of the c o l l o i d a l dust p a r t i c l e s i n t h e a i r i l l u m i n a t e d by t h e v e r t i c a l p l a n e of l i g h t coming through t h e l u c i t e .

The p o s i t i o n s o f the particles scattering the light c a n b e d e t e r m i n e d by s u p e r i m p o s i n g a p r e v i o u s l y determined photograph of

UNCLASSIFIED DWG 18663

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a grid system.

By s t r o b o s c o p i c f l a s h i n g of t h e l i g h t , s u c c e s s i v e p o s i t i o n s of s e v e r a l p a r t i c l e s can be o b t a i n e d ; f r o m known t i m e i n t e r v a l s b e t w e e n f l a s h e s and t h e p o s i t i o n s o f the p a r t i c l e s , the v e l o c i t y of the a i r c a n be m e a s u r e d a s a f u n c t i o n of radial position.

A modified version o f t h i s a n n u l u s s y s t e m c a n be u s e d t o study t h e hydrodynamic behavior of circulating- fuel reactors.

CIRCULATING-FUEL HEAT TRANSFER H. F. P o p p e n d i e k G. Winn Reactor Experimental Engineering Division T h e r m a l and h y d r o d y n a m i c b o u n d a r y layers are usually not established i n s h o r t - duc t c i r c u l a t i n g - f u e l s y s t e m s , such a s t h e F i r e b a l l , f o r example.

These systems a r e being s t u d i e d mathematically.

F o r some s p e c i f i c systems, t h e d i f f e r e n t i a l equations d e s c r i b i n g t h e b o u n d a r y - v a l u e p r o b lem have been transformed t o f i n i t e d i f f e r e n c e e q u a t i o n s and e v a l u a t e d numerically.

R e c e n t e v a l u a t i o n s have b e e n made w i t h t h e a i d of h i g h - s p e e d computing m a c h i n e s .

An a p p a r a t u s t h a t w i l l y i e l d e x p e r i m e n t a l i n f o r m a t i o n on t h e t h e r m a l s t r u c t u r e i n c i r c u l a t i n g - f u e l systems, i n b o t h t h e e n t r a n c e r e g i o n and t h e e s t a b l i s h e d f l o w r e g i o n , was b r i e f l y described previously. ( This a p p a r a t u s , which h a s been f a b r i c a t e d and a s s e m b l e d (shown s c h e m a t i c a l l y i n Fig. 12.41, c o n s i s t s of a c l o s e d loop t h a t c i r c u l a t e s a s u l f u r i c a c i d s o l u t i o n ; a volume h e a t s o u r c e i s generated within the c i r c u l a t i n g acid by m e a n s o f a n a l t e r n a t i n g c u r r e n t .

S e v e r a l o r i f i c e meters have been c a l i b r a t e d , and t h e power s u p p l y t h a t i s t o g e n e r a t e t h e volume h e a t s o u r c e and t h e t h e r m o c o u p l e s a r e t o be i n s t a l l e d next.

''

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Fig. 12.3. Schematic Diagram of the .-nnulus A p p a r a t u s f o r M e a s u r i n g Veloci ty Distributions.

162

('"H. F. P o p p e n d i e k and G. Winn, ANP Q u a r P r o g . R e p . D e c . 1 0 , 1 9 5 2 , OF"-1439, p . 1 8 5 .

; *

,

PERIOD ENDING MARCH 1 0 , 1953

COOLANT

COOLANT

Fig. 12.4.

Schematic Diagram of the Circulating-Fuel Heat Transfer Sys,tem.

URE REACTOR

imental Engineering

rtinent high-temperature coolants , p a r t i c u l a r l y f l i n a k , sodium h y d r o x i d e , bismuth, sodium, and a i r , i s being investigated.

C o m p a r i s o n s of t h e c i r c u l a t i o n v e l o c i t i e s , r a d i a l temperat u r e differences, a x i a l temperature

d i f f e r e n c e s , p r e s s u r e d r o p s , and pumping powers r e q u i r e d t o ac:hieve a s e r i e s of d i f f e r e n t c o o l i n g t a s k s a r e b e i n g made.

Because o f t h e l a r g e d i f f e r e n c e s i n p h y s i c a l p r o p e r t i e s of the various coolants being studied, b o t h l a m i n a r and t u r b u l e n t f l o w are encountered.

A t times, a s i g n i f i c a n t f r a c t i o n o f t h e c o o l a n t d u c t may l i e i n a t h e r m a l and hydrodynamic e n t r a n c e region; hence, entrance region heat t r a n s f e r is also involved in these studies.

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RADIATION DAMAGE

D. S. B i l l i n g t o n , S o l i d S t a t e D i v i s i o n

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E

c

Radiation-damage s t u d i e s of s t r u c t u r a l m a t e r i a l s , f u e l s , and o t h e r c o o l a n t s e x p o s e d i n t h e ORNL g r a p h i t e r e a c t o r a n d t h e LITR h a v e c o n t i n u e d .

Two I n c o n e l c a p s u l e s c o n t a i n i n g t h e ARE z i r c o n i u m - b e a r i n g f u e l w e r e i r r a d i a t e d i n t h e MTR a n d e x a m i n e d .

I n b o t h c a s e s , v a r i o u s p o r t i o n s of t h e capsule walls attained temperatures w e l l a b o v e 1500°F. T h e r e were i n d i c a t i o n s o f c h a n g e s i n t h e f u e l comp o s i t i o n , and c o r r o s i o n o c c u r r e d i n excess of t h a t i n out-of-reactor t e s t s a t 1500°F. A third irradiation is now i n p r o g r e s s i n t h e MTR, a n d , w i t h a more e l a b o r a t e c o n t r o l s y s t e m , a n a t t e m p t i s b e i n g made t o h o l d t h e maximum w a l l t e m p e r a t u r e a t 1 5 0 0 ° F .

Additional in-reactor cantilever c r e e p m e a s u r e m e n t s on I n c o n e l i n an a i r a t m o s p h e r e w e r e made i n b o t h t h e g r a p h i t e r e a c t o r a n d t h e LITR. In c o n f i r m a t i o n of p r e v i o u s o b s e r v a t i o n s , i t a p p e a r e d t h a t t h e i r r a d i a t i o n had l i t t l e e f f e c t on t h e c r e e p s t r e n g t h .

T h e s e and o t h e r r a d i a t i o n - d a m a g e studies are described.

Additional information is contained i n the S o lid S t a t e D i v i s i o n Q u a r t e r l y P r o g r e s s R e p o r t f o r t h e Period Ending F e b r u a r y 10, 1953, ORNL-1506.

IRRADIATION OF FUSED MATERIALS M. T. R o b i n s o n D. D. D a v i e s H. E. R o b e r t s o n A. R i c h t C. C. W e b s t e r W. J. Sturm n W. R. Willis M. J . Feldman i d State Division R. L. K n i g h t Electromagnetic Research D i v i s i o n

R. J. J o n e s

c

T h e r m a l - f l u x measurements were made with c o b a l t i n t h e fused s a l t t e s t i n g f a c i l i t y i n t h e M T R . The power d e n s i t y

i n t h e ARE t y p e o f f u e l was f o u n d t o be 2 7 0 0 w a t t s / c m 3 , r a t h e r t h a n t h e 1900 w a t t s / c m 3 p r e d i c t e d .

The w a l l t e m p e r a t u r e o f t h e f i r s t c a p s u l e o f t h e ARE t y p e o f f u e l i r r a d i a t e d i n t h e MTR was d e t e c t e d and c o n t r o l l e d by a s i n g l e t h e r m o c o u p l e .

E x a m i n a t i o n of t h e s u r f a c e i n c o n t a c t w i t h t h e f u e l d i s c l o s e d t h a t i3t l e a s t some p o r t i o n s o f t h e w a l l h a d b e e n h e a t e d t o t e m p e r a t u r e s f a r above 1500°F d u r i n g t h e 116 h r o f i r r a d i a t i o n .

In some s e c t i o n s , t h e I n c o n e l g r a i n s i z e hadbeen g r e a t l y increasedand c o r r o s i o n p e n e t r a t i o n o f up t o 1 0 t o 1 2 m i l s occasionally occurred.

In the regions o f n o r m a l g r a i n s i z e , t h e w a l l showed uniform, d e n s e , i n t e r g r a n u l a r c o r r o s i o n t h a t averaged about 2 m i l s i n depth, and t h e r e w e r e s u b s u r f a c e v o i d s 2 t o 4 m i l s deep.

T h e s e c o n d MTR f u e l c a p s u l e w a s i r r a d i a t e d f o r 325 h r and t h e w a l l t e m p e r a t u r e was d e t e c t e d a t t w o p o i n t s .

The c o n t r o l t h e r m o c o u p l e h e l d t h e c a p s u l e w a l l l o c a l l y a t 1500"F, b u t the second thermocouple, several m i l l i m e t e r s away, r e c o r d e d t e m p e r a t u r e s a s h i g h a s 1 7 4 0 ° F . E x a m i n a t i o n of t h e I n c o n e l i n t h i s c a s e showed o n l y dense, intergranular corrosion t h a t averaged about 2 m i l s i n d e p t h .

S e a l e d I n c o n e l c a p s u l e s t h a t had been p r e p a r e d f o r i r r a d i a t i o n i n t h e MTR w e r e x r a y e d , and t h e p h o ' t o g r a p h showed t h a t t h e f u e l was n o t s o l i d l y packed i n t o t h e 100-mil-ID f u e l chamber.

Rather than occupying t h e b o t t o m o f t h e c h a m b e r , t h e f u e l was s c a t t e r e d o v e r t h e l e n g t h , and t h u s t h e r e were numerous v o i d s i n what had been assumed t o be a s o l i d f u e l column.

C o n s i d e r a b l e s t u d y was g i v e n t o t h e f i l l i n g and t e m p e r a t u r e c o n t r o l techniques.

A t h i r d c a p s u l e , which i s c u r r e n t l y b e i n g i r r a d i a t e d i n t h e MTR,

16 5

ANP PROJECT QUARTERLY PROGRESS REPORT was f i l l e d by an i m p r o v e d method, and i t was o b s e r v e d w i t h x r a y s t h a t t h e f u e l formed a n e a r l y continuous 1 0 0 - m i l - d i a c o l u m n i n t h e lower 1/2 i n . o f t h e f u e l chamber.

A rod attached t o t h e c a p o f t h e c a p s u l e was f i t t e d t i g h t l y i n t o t h e f u e l chamber t o p r e s s on t h e t o p o f t h e f u e l t o h e l p hold it i n place.

Three thermocouples w e r e s p o t t e d on t h e o u t s i d e c h a m b e r walls t o record the temperatures i n v a r i o u s l o c a t i o n s , and t h e y were instrumented s o t h a t the temperature c o u l d b e r e g u l a t e d by m e a n s o f t h e h o t t e s t thermocouple.

During t h e course of t h e experiment t h e middle t h e r m o c o u p l e h a s been damaged, and t h e t e m p e r a t u r e i s now c o n t r o l l e d by t h e t o p and b o t t o m t h e r m o c o u p l e s .

C h e m i c a l a n a l y s e s and a n a l y s e s f o r t h e f i s s i o n p r o d u c t C S ' ~w e~r e c a r r i e d o u t on t h e two f u e l s a m p l e s i r r a d i a t e d i n t h e MTR. S i n c e t h e r e i s some d o u b t a s t o how t h o r o u g h l y t h e f u e l w a s d i s s o l v e d d u r i n g t h e c o u r s e of t h e a n a l y t i c a l work, t h e r e i s some d o u b t a s t o t h e v a l i d i t y of t h e a n a l y t i c a l Work i s under way t o improve results. t h e m e t h o d s o f d i s s o l u t i o n of t h e f u e l .

However, a t r e n d t h a t w a r r a n t s m e n t i o n w a s i n d i c a t e d by t h e a n a l y t i c a l r e s u l t s . T h e r e was i n d i c a t i o n t h a t t h e f u e l which c o u l d be r e a d i l y m e l t e d o u t o f t h e c a p s u l e was more d e f i c i e n t i n uranium t h a n c o u l d be a c c o u n t e d f o r by b u r n u p .

This deficiency in uranium d i d n o t occur i n t h e c o n t r o l s h e a t e d on t h e b e n c h a t 1 5 0 0 째 F f o r an e q u i v a l e n t number o f h o u r s .

In addit i o n , when t h e C S ' ~ ' was c o u n t e d i n t h e f u e l t h a t had b e e n m e l t e d o u t , t h e r e was l e s s d e t e c t e d t h a n w o u l d b e e x p e c t e d f r om t h e t h e r m a I f 1ux measurements.

I n one c a s e , t h e d i s c r e p a n c y i n C S ' ~c o~r r e s p o n d e d f a i r l y closely with the discrepancy i n u r a n i u m c o n t e n t , 33% a n d 28%, and led t o the supposition that the uranium had been s e g r e g a t e d d u r i n g t h e e a r l y portion of the i r r a d i a t i o n period.

However, t h e s h o r t a g e i n cesium might have been due t o e s c a p e

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166

c

o f xenon i n t o t h e c a p s u l e f r e e s p a c e and s u b s e q u e n t d e p o s i t i o n o f c e s i u m on t h e w a l l s .

I f i t i s assumed t h e r e a r e n o c o n vection currents i n the capsule to relieve the temperature gradients, the c e n t r a l p o r t i o n of t h e f u e l i s c a l c u l a t e d t o be 1200째F h o t t e r t h a n the f u e l a t t h e w a l l , which t h e t h e r m o c o u p l e s t r y t o h o l d a t 1500째F. Whether t h e a p p a r e n t u r a n i u m s e g r e g a t i o n was due t o w h a t e v e r t e m p e r a t u r e g r a d i e n t s may have e x i s t e d , t h e g e n e r a l overheating of the capsule, f a u l t y a n a l y s e s , or t o r a d i a t i o n - d a m a g e i s a question that requires further investigation.

In irradiations c a r r i e d o u t s e v e r a l months ago w i t h t h e Y-12 C y c l o t r o n and by N o r t h A m e r i c a n A v i a t i o n ( ) on t h e B e r k e l e y C y c l o t r o n , some e v i d e n c e s o f u r a n i u m s e g r e g a t i o n i n t h e v a r i o u s f u e l s were a l s o n o t e d , b u t t h e q u e s t i o n o f unc e r t a i n thermal h i s t o r y e x i s t s for these cases too.

Before opening, the f i r s t capsule i r r a d i a t e d i n t h e MTR w a s h e a t e d t o w e l l above t h e normal m e l t i n g p o i n t of t h e f u e l and i t s f r e e z i n g p o i n t was compared w i t h t h a t of u n i r r a d i a t e d f u e l i n a s i m i l a r c a p s u l e by means o f a d i f f e r e n t i a l thermocouple a r r a n g e ment.

The m e l t i n g p o i n t of t h e i r r a d i a t e d f u e l a p p e a r e d t o b e 23OF h i g h e r , b u t t h e d i f f e r e n c e was w i t h i n t h e range o f e x p e r i m e n t a l e r r o r .

In a s i m i l a r experiment, a sample of f u e l i r r a d i a t e d f o r 140 h r i n the LITR a t 140 w a t t s / c m 3 a p p e a r e d t o have an l l 째 F lower m e l t i n g p o i n t t h a n i t s corresponding u n i r r a d i a t e d bench tests.

O n l y a s m a l l amount o f work i s now b e i n g d o n e on r a d i a t i o n d a m a g e with t h e Y-12 Cyclotron.

T h i s work i n c l u d e d an i n v e s t i g a t i o n o f m e t h o d s f o r helium-cooling t a r g e t s containing f u s e d f l u o r i d e s ; t h e s t u d y h a s been discontinued.

A l s o , some w o r k i s (l)W. V . G o d d e l l e t a l . , C y c l o t r o n I r r a d i a t i o n o f Fused F l u o r i d e s

cn I n c o n e l a t E l e v a t e d T e a p e r a t u r e s , NAA-SR-208 (Jan. 2 6 , 1953).

i

PERIOD ENDING MARCH 1 0 , 1953 being c a r r i e d out t o determine the u s e f u l n e s s of p r o t o n b o m b a r d m e n t a s a m e t h o d f o r s t u d y i n g h y d r o g e n emb r i t t l e m e n t i n metals.

IN-REACTOR CIRCULATING LOOPS 0.

W. J. A. M.

S1‘ sman R. M. C a r r o l l W. P a r k i n s o n C. D. Bauman B. T r i c e C. E l l i s S. O l s o n W. E. Brundage T. Morgan F. M. B l a c k s h e r Solid State Division

The l o o p p r e v i o u s l y r e p o r t e d ( 2 ) a s h a v i n g c i r c u l a t e d s o d i u m i n t h e LITR f o r a w e e k was e x a m i n e d t o d e t e r m i n e t h e c a u s e of s t o p p a g e of flow.

It was f o u n d t h a t t h e d i f f i c u l t y was d u e t o a leak i n the Inconel tubing t h a t caused a l o w e r i n g of t h e sodium l e v e l i n t h e surge tank.

Additional experiments were c a r r i e d out w i t h sodium loops i n the graphite r e a c t o r while i m p r o v e m e n t s w e r e b e i n g made i n t h e d e s i g n o f t h e LITR l o o p .

Development c o n t i n u e d on a pump f o r u s e w i t h a n in-reactor fluoride-fuel-circulating system.

CREEP UNDER IRRADIATION W. W. D a v i s J. C. Wilson J. C. Zukas Solid S t a t e Division S e v e r a l new t e s t s h a v e b e e n comp l e t e d on a n n e a l e d I n c o n e l a t 1500’F w i t h s t r e s s e s o f 3000 and 4000 p s i i n a i r i n b o t h t h e LITR and t h e g r a p h i t e reactor.

The s p r e a d i n t h e d a t a and some v a r i a t i o n s i n e x p e r i m e n t a l c o n d i t i o n s a l l o w no q u a n t i t a t i v e e s t i m a t e s t o b e made o f t h e e f f e c t o f n e u t r o n b o m b a r d m e n t on reep, but it can s a f e l y be s a i d t h a t t h e e f f e c t i s n o t g r e a t enough t o c a u s e m a t e r i a l change i n the design stress values f o r these m a t e r i a l s under t h e s e experimental conditions.

The n e x t work t o be

p e r f o r m e d w i l l be t o a s s e s s t h e e f f e c t o f t h e a t m o s p h e r e i n which t h e s p e c i m e n i s t e s t e d , s i n c e t h i s i s known t o b e an i m p o r t a n t f a c t o r i n t h e c r e e p s t r e n g t h of I n c o n e l . ( ’ ) In Fig. 13.1, the 4000-psi d a t a show t h a t l e s s c r e e p was e x p e r i e n c e d under i r r a d i a t i o n t h a n i n t h e s i n g l e bench t e s t .

The odd s h a p e o f c u r v e X - 1 i s b e l i e v e d t o have been c a u s e d by t h e l o a d i n g w e i g h t r e s t i n g a g a i n s t the microformer during the e a r l y part of the test.

The d i f f e r e n c e b e t w e e n t h e L I T R c u r v e s may h a v e r e s u l t e d b e c a u s e t h e t e s t s h o w n by c u r v e L-2 r e c e i v e d 24 h r o f i r r a d i a t i o n b e f o r e t h e f u r n a c e was t u r n e d on and t h e s p e c i m e n was s t r e s s e d .

The t o t a l s t r a i n s i n e a c h o f t w o , 3OOO-psi, g r a p h i t e r e a c t o r t e s t s , a n d o n e LITR t e s t , s h o w n i n F i g . 1 3 . 2 , a r e i n good a g r e e m e n t w i t h t h e v a l u e s for similar t e s t s reported earlier.C4) On t h e b a s i s o f t h e s i n g l e b e n c h t e s t t o which a l l t h e i n - r e a c t o r c u r v e s a r e compared, it i s n o t p o s s i b l e t o say whether moreor l e s s c r e e p r e s u l t e d from i r r a d i a t i o n .

A t t h e e n d of t h e q u a r t e r , two t e s t s were o p e r a t i n g i n t h e LITR i n a h e l i u m a t m o s p h e r e a n d d u p l i c a t e bench t e s t s were a b o u t t o be s t a r t e d .

Annealed I n c o n e l and t y p e 347 s t a i n l e s s s t e e l b a r s were e x p o s e d f o r a one-week p e r i o d i n h o l e HB-3 o f t h e LITR i n a g r a d i e n t f u r n a c e t o d e t e r m i n e t h e h i g h e s t temperature a t which n e u t r o n bombardment would c a u s e an increase i n hardness of the metals.

The t e m p e r a t u r e g r a d i e n t was f r o m 1700 t o 1150°F o v e r 4 . 5 - i n . s p e c i m e n s .

R o c k w e l l B h a r d n e s s m e a s u r e m e n t s were made a f t e r i r r a d i a t i o n a n d c o m p a r e d t o t h e i n i t i a l h a r d n e s s and t o t h e hardness of c o n t r o l b a r s s u b j e c t e d t o t h e same t i m e and t e m p e r a t u r e h i s t o r y a s t h e i n - r e a c t o r specimens.

The I n c o n e l was h a r d e n e d s l i g h t l y by (3)ANP

Qua,.

Prog. Rep.

1439, Fig. 1 4 . 1 , p.

(2)ANP Quar. Prog. R e p . D e c .

1439, p . 1 8 7 .

1 0 , 1 9 5 2 , ORNL-

D e c . 10, 1 9 5 2 , ORNL-

188.

(4’Solzd S t a t e Quar. Prog. Rep. Nov. 10, 1952, ORNL-1429, F i g . 2 , p . 7.

6 .

167

ANP PROJECT QUARTERLY PROGRESS REPORT

0.24

8 0.20 Y

z

-

0 v)

z 0.16 X

w E 4 W

m 0.12

cr w

>

0.04

0

600

400

200

0

TIME (hr)

Fig. 13.1.

4000 psi.

In-Reactor Cantilever Creep Tests o n Inconel in Air at 1500'F

bombardment a t t e m p e r a t u r e s a s h i g h a s 1550'F. The s t a i n l e s s s t e e l showed an i n c r e a s e i n h a r d n e s s o n l y a t t e m p e r a t u r e s below 1400째F. Earlier work o n t y p e 3 4 1 s t a i n l e s s s t e e l ( ' ) i n d i c a t e d t h a t b e l o w 1400째F t h e c r e e p r a t e o f t h e m a t e r i a l was r e d u c e d by n e u t r o n bombardment, whereas d a t a taken a t 1500째F i n d i c a t e d t h a t i n creased creep resulted during i r r a d i ("Solid S t a t e Q u a r . P r o g . R e p . May IO. 1 9 5 2 , OWL-1301, F i g . 2 . p. 6 . f

a

and

a t ion.

A qual i t a t i v e c o r respondence c o u l d be e x p e c t e d i n I n c o n e l , and t h e h a r d n e s s d a t a may h e l p t o e x p l a i n why no s u b s t a n t i a l e f f e c t s o f i r r a d i a t i o n have y e t b e e n o b s e r v e d .

Because t h e s t e e p g r a d i e n t s i n t h e experiment r e p o r t e d h e r e do n o t p e r m i t a c c u r a t e d e t e r m i n a t i o n of t e m p e r a t u r e , h a r d n e s s b l o c k s w i l l be p l a c e d a l o n g s i d e t h e creep specimens i n f u t u r e tests t o e n a b l e more p r e c i s e d e t e r m i n a t i o n o f i r r a d i a t i o n hardening conditions at s eve r a 1 temper a t u r e s

.

a

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 MtE;F

SSD -A-706 DWG. fa008

-

0.12 ANNEALED 2 hr AT 1700째 F

z

0 cn

5

0.08

I-

X

W

LT

w

> W

0.02

0 0

200

400

600

TIME (hr) Fig. 13.2.

3000 p s i .

I n - R e a c t o r C a n t i l e v e r Creep T e s t s o n I n c o n e l i n Air a t 1501DOF and

169

14. ANALYTICAL STUDIES OF REACTOR MATERIALS C. D. S u s a n o , A n a l y t i c a l C h e m i s t r y D i v i s i o n

J . M. Warde, M e t a l l u r g y D i v i s i o n

a

The work on r e a c t o r f u e l components d u r i n g t h e p a s t q u a r t e r h a s produced a s a t i s f a c t o r y method f o r t h e d e t e r m i nation of zirconium i n the presence of uranium.

A method was a l s o d e v e l o p e d by w h i c h t h e r e d u c t i o n p r o d u c t s , uranium t r i f l u o r id e and z i r conium m e t a l , may be d e t e r m i n e d i n t h e p r e s e n c e o f one a n o t h e r .

These reduced s p e c i e s may be f o r m e d upon e x c e s s i v e a d d i t i o n of a c o r r o s i o n i n h i b i t o r such a s a h y d r i d e o r NaK t o t h e ARE f u e l m i x t u r e .

S t u d y h a s a l s o been c o n c e n t r a t e d on d e v e l o p i n g methods f o r t h e d e t e r m i nation of contaminants i n the f l u o r i d e fuel mixtures.

An a p p a r a t u s h a s b e e n developed and t e s t e d i n which t r a c e s of m e t a l l i c oxides i n f l u o r i d e mixtures may be d e t e r m i n e d . T h e d e t e r m i n a t i o n of t r a c e q u a n t i t i e s of hydrogen f l u o r i d e i n helium iisexpedient during the f i n a l s t a g e s of t h e f u e l p r e p a r a t i o n p r o c e s s , and a method f o r r a p i d l y a c c o m p l i s h i n g t h i s a t t h e s i t e of t h e f u e l p r e p a r a t i o n h a s been d e v e l o p e d .

A s t u d y i L s b e i n g made o f t h e compounds formed between f l u o r i d e melts and their containers.

Residues of t h e s e c o r r o s i o n p r o d u c t s a r e b e i n g examined a n a l y t i c a l l y and s p e c t r o g r a p h i c a l l y .

T h e s y s t e m s UC14-NaC1 and UCl,-KCl h a v e been examined p e t r o g r a p h i c a l l y t o d e t e r m i n e compound a n d e u t e c t i c compositions.

Optical data a r e included f o r t h e compounds i n t h e s e s y s t e m s .

P h a s e s p r e s e n t i n t h e NaF-ZrF,-UF, system have been s t u d i e d p e t r o g r a p h i c a l l y a n d by x - r a y d i f f r a c t i o n i n an e f f o r t t o d e f i n e t h e t e r n a r y and p s e u d o b i n a r y p h a s e r e g i o n s and t o i d e n t i f y t h e compounds t h e r e i n .

Data f o r the compositions s t u d i e d t o d a t e a r e included.

T h e b u l k o f work p e r f o r m e d by t h e s e r v i c e groups d u r i n g t h e p a s t q u a r t e r i n v o l v e d c h e m i c a l a n a l y s e s and p e t r o -

graphic examination of fluoride mixtures.

In addition, chemical a n a l y s e s were p e r f o r m e d on a g r o u p o f t e s t s e c t i o n s from t h e b e r y l l i u m o x i d e v s . NaK t e s t s , and o x i d e d e t e r m i n a t i o n s w e r e made on a number o f c h l o r i d e and f l u o r i d e samples.

CHEMICAL A N A L Y S I S OF REACTOR F U E L S AND CONTAMINANTS

J . C. W h i t e Analytical Chemistry Division

A new v o l u m e t r i c m e t h o d f o r t h e d e t e r m i n a t i o n o f z i r c o n i u m was d e veloped.

T h i s method c o n s i s t s o f dissolving the zirconium s a l t of p-chloromandelic a c i d i n a nonaqueous medium w i t h e x c e s s s o d i u m m e t h y l a t e and back t i t r a t i n g w i t h a c e t i c a c i d .

The r e a c t i o n i n v o l v e d i s s t o i c h i o m e t r i c ; hence, no empirical f a c t o r s a r e i n vol ved A method f o r t h e d e t e r m i n a t i o n o f uranium t r i f l u o r i d e and zirconium m e t a l , which a r e formed upon t h e a d d i t i o n of zirconium hydride or o t h e r s i m i l a r c o r r o s i o n i n h i b i t o r s , was developed.

These d e t e r m i n a t i o n s can be made i n t h e p r e s e n c e o f e a c h o t h e r because of t h e g r e a t d i f f e r e n t i a l r e a c t i o n r a t e s o f t h e s e two m a t e r i a l s with d i l u t e hydrofluoric acid reagent.

The r e a c t i o n s o f bromine t r i f l u o r i d e with metallic oxides a r e being studied i n an e f f o r t t o measure t r a c e amounts o f o x i d e i n f l u o r i d e m i x t u r e s and a l s o t o determine t h e completeness of f l u o r i n a t i o n of zirconium oxide d u r i n g the preparation of t h e fluoride.

A method f o r t h e d e t e r m i n a t i o n o f t r a c e s of hydrogen f l u o r i d e i n helium s w e e p i n g s o f f u e l p r e p a r a t i o n s was developed i n which t h e gas i s t r a p p e d i n b o r i c a c i d s o l u t i o n . The i n c r e a s e i n conductivity of the s o l u t i o n caused

.

17 1

ANP PROJECT QUARTERLY PROGRESS REPORT by f l u o b o r i c a c i d f o r m e d b y t h e r e a c t i o n b e t w e e n HF and b o r i c a c i d i s m e a s u r e d and r e l a t e d a s a f u n c t i o n o f t h e c o n c e n t r a t i o n of hydrogen f l u o r i d e .

C o n c e n t r a t i o n s of t h e o r d e r o f 1 x l o - ' M HF c a n be d e t e r m i n e d i n t h i s manner.

The d i s s o l u t i o n o f I n c o n e l c o n t a i n e r s , w h i c h h a v e b e e n c o r r o d e d by f l u o r i d e r e a c t o r f u e l s , was a t t e m p t e d e l e c t r o l y t i c a l l y i n s u c h a manner a s t o s e p a r a t e m e t a l s from compounds. The

d e t e r m i n i n g z i r c o n i u m h a s been d e veloped i n which t h e p - h a l o m a n d e l a t e s a l t is dissolved i n excess standard sodium methoxide s o l u t i o n c o n t a i n i n g 3 p a r t s benzene and 1 p a r t methanol, and t h e e x c e s s b a s e i s t i t r a t e d w i t h standard acetic acid i n a similar b e n z e n e - m e t h a n o l s o l u t i o n w i t h thymol blue used a s the i n d i c a t o r .

The equation for t h e reaction t h a t takes place is:

Z r (p-C1C,H4CHOHC00), + 4NaOCH, 4 4Na p-C1C,H4CHOHC00 amount of t h e d a t a c o l l e c t e d is i n s u f f i c i e n t t o p e r m i t drawing any d e f i n i t e conclusions.

Z i r c o n i u m (C. K. T a l b o t t , J . M. McCown, A n a l y t i c a l C h e m i s t r y D i v i s i o n ) .

O f t h e s e v e r a l p r o c e d u r e s e x p l o r e d for t h e determination of zirconium,(') t h e s i m p l e s t and m o s t a c c u r a t e i s a v o l u m e t r i c method e m p l o y i n g m a n d e l i c a c i d , T h i s r e a g e n t i s e s p e c i a l l y good f o r determining zirconium i n the presence o f uranium.

I t was d e c i d e d t o f u r t h e r i n v e s t i g a t e r e a g e n t s of t h e mandelic a c i d t y p e , and a v o l u m e t r i c p r o c e d u r e was d e v e l o p e d e m p l o y i n g p - b r o m o m a n d e l i c and p - c h l o r o m a n d e l i c a c i d s .

These a c i d s p r e c i p i t a t e zirconium i n a c i d i c s o l u t i o n i n t h e form o f z i r c o n i u m t e t r a p-bromo(chloro)mandelate, which i s more e a s i l y f i l t e r e d t h a n t h e z i r conium m a n d e l a t e . ( I t is possible t o t h e n d r y t h i s s a l t and d e t e r m i n e z i r conium g r a v i m e t r i c a l l y , 3, but the v o l u m e t r i c method is s i m p l e r t o execute. 1 The s a l t d i s s o l v e s i n a l k a l i w i t h subsequent hydrolysis of zirconium.

H o w e v e r , when a n a l k a l i i s u s e d i n a n o n a q u e o u s medium t o d i s s o l v e t h e s a l t , h y d r o l y s i s does n o t occur.

On t h i s b a s i s , a v o l u m e t r i c method f o r ("ANP Quar. P r o g . R e p . D e c . 1 0 , 1 9 5 2 , ORNL1 4 3 9 , p. 1 9 1 .

("R. ,.,, "'R.

B. Hahn, A n a l . C h e r . 2 3 , 1259 ( 1 9 5 1 ) .

E. Oesper a n d J . L. K l i n g e n b e r g , A n a l .

C h e a . 2 1 , 1509 ( 1 9 4 9 ) .

17 2

-I- Z r

(OCH,

I4

.

The r e a c t i o n , w h i c h a p p e a r s t o be s t o i c h i o m e t r i c , e l i m i n a t e s t h e need f o r t h e u s e of e m p i r i c a l f a c t o r s . The limited availability of the reagent h a s made n e c e s s a r y t h e s y n t h e s i s o f p-chloromandelic acid.

A method p r o p o s e d by J e n k i n s ( 4 ) h a s b e e n u s e d f o r t h i s p r e p a r a t i o n ; a y i e l d o f 50% is obtained.

Reduction P r o d u c t s (W. J . R O S S , Analytical Chemistry D i v i s i o n ) .

The addition of zirconium hydride t o inhibit corrosion i n fluoride reactor f u e l s has l e d t o a study of the reduction products t h a t appear a s a result of this addition, It i s p o s t u l a t e d t h a t some u r a n i u m t e t r a f l u o r i d e w i l l be r e d u c e d t o t h e t r i f l u o r i d e and t h a t z i r c o n i u m m e t a l w i l l be formed. A p r o c e d u r e i n which i t i s possible t o determine both these s p e c i e s , u r a n i u m t r i f l u o r i d e and z i r conium m e t a l , i n t h e same s a m p l e o f r e a c t o r f u e l h a s been d e v e l o p e d .

The p r o c e d u r e i s b a s e d on t h e v a s t d i f ferences i n the r a t e s of the following r e a c t i o n s w i t h 0 . 2 M HF:

Z r + 6HF

H2ZrF, + 2H,,

2UF3 t 2HF +2UF4

-t

H,,

fast,

(1)

slow.

(2)

Reaction 1 proceeds q u a n t i t a t i v e l y a t room t e m p e r a t u r e , w h e r e a s r e a c t i o n 2 (4)S. S. J e n k i n s , J . A B . C h e a .

(1931).

SOC. 53,

2341

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 e x h i b i t s no t e n d e n c y t o r e a c t u n d e r t h i s c o n d i t i o n f o r some t i m e . A s t u d y of the r a t e of r e a c t i o n 2 is incomplete; h o w e v e r , upon h e a t i n g f o r 1 h r a t 9 0 째 C , o n l y 5.2% o f t h e t h e o r e t i c a l amount o f These r e s u l t s hydrogen i s evolved. i l l u s t r a t e t h e s t a b i l i t y o f uranium t r i f l u o r i c d e i n t h i s medium.

When a mixture of zirconium and uranium t r i f l u o r i d e was t r e a t e d w i t h 0 . 2 M HF, t h e volume o f h y d r o g e n l i b e r a t e d was e q u i v a l e n t t o t h e amount o f z i r c o n i u m present: Zr -t 4HCl---+ ZrC1, -t 2H2, , slow,

4uF3 + LWCl

c

e.

-

3w4 -t

uc1, -t

2H,,

fast.

Zirconium l i b e r a t e s 4.9% of t h e t h e o r e t i c a l volume o f hydrogen upon h e a t i n g f o r 1 h r a t 90째C i n 9 . 6 M HC1.

Uranium t r i f l u o r i d e r e a c t s q u a n t i t a t i v e l y , a s s h o w n by M a n n i n g ( ' ) i n h i s method f o r t h e d e t e r m i n a t i o n o f uranium t r i f l u o r i d e .

When a m i x t u r e o f t h e t w o i s t r e a t e d w i t h 9 . 6 M HC1, hydrogen e q u i v a l e n t t o t h e t o t a l z i r conium and u r a n i u m t r i f l u o r i d e p r e s e n t i s l i b e r a t e d i n a p p r o x i m a t e l y 2 0 min T h i s r e a c t i o n c a n be e x a t 9OOC. p l a i n e d on t h e b a s i s o f f o r m a t i o n o f a c o m p l e x i o n by z i r c o n i u m w i t h t h e f l u o r i d e i o n s t h a t a r e l i b e r a t e d by h y d r o c h l o r i c a c i d a t t a c k on t h e uranium t r i f 1uori.de.

A two-step oxidation reaction is, i n e f f e c t , used t o determine zirconium and u r a n i u m t r i f l u o r i d e i n t h e p r e s e n c e of each other.

A s o l u t i o n of 0.2 M HF i s a d d e d t o t h e m i x t u r e a n d t h e volume o f h y d r o g e n e v o l v e d f r o m t h i s r e a c t i o n , c o n d u c t e d a t room t e m p e r a t u r e , is c a l c u l a t e d a s zirconium.

A s o l u t i o n o f 9 . 6 M HC1 i s t h e n a d d e d , w i t h b o r i c a c i d , t p complex e x c e s s f l u o r i d e i o n s , and t h e volume o f hydrogen evolved upon h e a t i n g is c a l c u l a t e d a s uranium t r i f l u o r i d e . ("D. Jr.,

L. Manning,

W.

P r e l i m i n a r y r e s u l t s have been extremely promising, The e f f e c t o f l a r g e e x c e s s e s of sodium, zirconium, a n d u r a n i u m t e t r a f l u o r i d e s on t h e s e r e a c t i o n s is being studied.

Oxides ( J . E . L e e , J r . , A n a l y t i c a l Chemistry D i v i s i o n ) . M e t a l l i c oxides r e a c t w i t h bromine t r i f l u o r i d e ( 6 ) according t o the reaction

-

3 M 0 2 t 4BrF3 3MF, -t 2 B r 2 + 30, , where M r e p r e s e n t s a q u a d r i v a l e n t cation.

The m e t a l l i c o x i d e c o n t e n t c a n b e d e t e r m i n e d by m e a s u r i n g t h e amount o f o x y g e n e v o l v e d ; h e n c e , t h i s r e a c t i o n i s of p o t e n t i a l i n t e r e s t i n determining t h e oxide content of fluoride mixtures.

A schematic diagram of t h e apparatus constructed for use i n studying t h i s t y p e o f r e a c t i o n i s shown i n F i g . 14.1.

The r e a c t o r p o r t i o n i s d e s i g n e d s o t h a t r e a c t i o n p r e s s u r e s o f up t o t h e o r d e r of 1 t s i can be p e r m i t t e d .

The remainder of the system c o n s i s t s of a r e a g e n t t r a n s f e r a r r a n g e m e n t , i n which t r a n s f e r may be made u n d e r vacuum, and a high-vacuum s y s t e m w i t h t h e n e c e s s a r y instrumentation for measuring the oxygen l i b e r a t e d d u r i n g t h e r e a c t i o n .

Several samples of zirconium oxide h a v e been f l u o r i n a t e d w i t h chromium t r i f l u o r i d e i n t h i s equipment a t t e m p e r a t u r e s r a n g i n g from 200 t o 300째C. Analyses of t h e reaction residues i n d i c a t e t h a t t h e experimental cond i t i o n s employed t h u s f a r h a v e r e s u l t e d i n f l u o r i n a t i o n s t h a t a r e a t l e a s t 80% complete.

E f f o r t s a r e b e i n g made t o o b t a i n q u a n t i t a t i v e f l u o r i n a t i o n by means o f s u c h p r o m o t e r s a s u r a n i u m dioxide, Hydrogen Fluoride (D. L. M a n n i n g , Analytical Chemistry Division).

A possible explanation of the corrosiven e s s o f r e a c t o r f u e l s t h a t have been t r e a t e d with hydrogen f l u o r i d e i s t h e presence of the gas entrapped i n the s o l i d i f i e d melt.

I n o r d e r t o remove t h i s gas from t h e m o l t e n f u e l , a n

K . M i l l e r , and R. Rowan,

M e t h o d s of D e t e r m i n a t i o n o f f l u o r i d e , OWL-1279 (May 2 5 , 1 9 5 2 ) .

Vrantun T r t -

p.

( 6 ) H . J . Emeleus and A. 164-168 ( 1 9 5 0 ) .

A.

Woolf, J . Chem. S O C . ,

17 3

ANP PROJECT QUARTERLY PROGRESS REPORT UNCLASSIFIED DWG. 18665

T F i g . 14.1.

I

c-REACTOR

Apparatus f o r S t u d y i n g R e a c t i o n s w i t h Bromine T r i f l u o r i d e .

o u t g a s s i n g - w i t h - h e l i u m s t e p h a s been included i n the fuel preparation procedure.

It is d e s i r e d t o t e s t t h e helium o f f - g a s f o r hydrogen f l u o r i d e and t o monitor t h e gas stream.

The most a t t r a c t i v e means o f a t t a c k i n g t h i s p r o b l e m a p p e a r s t o be t h e m e a s u r e ment of t h e c o n d u c t i v i t y of t h e

17 4

s c r u b b i n g s o l u t i o n s through which t h e gases are passed.

This type of a n a l y s i s is r a p i d a n d h a s t h e a d d e d a d v a n t a g e t h a t i t may be made a t t h e s i t e of the experiment.

Several s c r u b b i n g s o l u t i o n s were s t u d i e d , a n d t h e most p r o m i s i n g were c a l c i u m h y d r o x i d e and b o r i c a c i d .

PERIOD ENDING MARCH 10, 1953 Calcium hydroxide r e a c t s w i t h hyd r o g e n f l u o r i d e i n t h e f o l l o w i n g manner:

+ 2011- + 2HF + C a F 2 + 2 H 2 0

Cat+

and reduces t h e c o n d u c t i v i t y of t h e s o l u t i o n 13y r e m o v i n g h y d r o x y , l i o n s .

Approximately 100 p g o f hydrogen f l u o r i d e reduced t h e c o n d u c t i v i t y o f 100 m l o f 7 X N calcium hydroxide s o l u t i o n by 7 X mho.

A more s e n s i t i v e determination is p o s s i b l e i f b o r i c a c i d is used a s t h e s c r u b b i n g solution.

The r e a c t i o n t h a t o c c u r s between hydrogen f l u o r i d e and b o r i c a c i d is

H,BO,

+ 4HF

-

H+ + BF; + 3H,O

,

i n which a s t r o n g a c i d ( f l u o b o r i c ) i s formed; t h e r e f o r e t h e h i g h l y mobile hydrogen i o n i s i n t r o d u c e d i n t o t h e system and t h e c o n d u c t i v i t y i s ipcreased.

The c o n c e n t r a t i o n o f t h e b o r i c a c i d s o l u t i o n s h o u l d be v e r y d i l u t e , 0 . 1 w t 76 or l e s s , s o t h a t t h e conductivity of the scrubbing solution w i l l be e x t r e m e l y l o w , o f t h e o r d e r o f 2 x mho.

The c o n d u c t i v i t y o f 100 m l o f 3 X lo', M b o r i c a c i d i s increased 13.5 X mho b y t h e a d d i t i o n o f 100 p g o f h y d r o g e n f l u o r i d e - a change n e a r l y twice t h a t produced by t h e same amount o f h y d r o g e n f l u o r i d e i n calcium hydroxide s o l u t i o n . These r e s u l t s show t h a t c o n d u c t i v i t y m e a s u r e m e n t s a r e ' e x t r e m e l y s e n s i t i v e and w e l l

s u i t e d for the purpose of determining hydrogen f l u o r ide.

C o r r o s i o n P r o d u c t s (D. L. M a n n i n g , A n a l y t i c a l Chemistry D i v i s i o n ) .

Exp e r i m e n t s have been conducted t o ascertain the e f f e c t s of molten f l u o r i d e s a l t m i x t u r e s on I n c o n e l a n d other metallic containers.

In these experiments, the metal container t h a t h a s b e e n e x p o s e d t o f l u o r i d e s i s made t h e anode i n a s u l f u r i c a c i d - c i t r i c acid bath.

Since the metals e x i s t a s elements, they a r e e l e c t r o l y t i c a l l y d i s s o l v e d and t h e r e b y s e p a r a t e d from t h e compounds p r e s e n t . A s i m i l a r m e t a l tube i s dissolved for comparative p u r p o s e s . The r e s i d u e s from t h e a n o d i c d i s s o l u t i o n h a v e been a n a l y z e d chemic a l l y and s p e c t r o g r a p h i c a l l y .

The a n a l y t i c a l methods used t o d a t e have been u n r e l i a b l e because o f f l a k i n g o f metal p a r t i c l e s during d i s s o l u t i o n .

Refinements i n the e l e c t r o d e system a r e b e i n g made t o e l i m i n a t e t h i s difficulty.

S p e c t r o g r a p h i c d a t a have been c o l l e c t e d f o r I n c o n e l specimens t h a t were s u b j e c t e d t o t h e s t a n d a r d 100-hr s t a t i c corrosion test with NaF-ZrF4-UF,, w i t h and w i t h o u t a d d i t i o n o f z i r c o n i u m h y d r i d e . The r e s u l t s a r e given i n Table 14.1.

The amount o f t h e d a t a c o l l e c t e d i s i n s u f f i c i e n t t o permit drawing d e f i n i t e conclusions.

Several points of i n t e r e s t a r e e v i d e n t , however.

The

T A B L E 1 4 . 1 . S P E C T R O G R A P H I C A N A L Y S E S OF R E S I D U E S FROM A N O D I C D I S S O L U T I O N OF I N C O N E L U S E D I N S T A T I C C O R R O S I O N T E S T S OF F L U O R I D E REACTOR F U E L S REACTOR FUEL

COB E I T I O N O F RESIDUE FROM DISSOLUTIOI )F INCONEL (%) Si Zr U A1 co Ti

> 20

0.2

1.0

ND*

0.08

10

0.2

0.6

ND

0.1

20

ND

0.2

<o. 1 <o. 1

0.2

<o. 1

0.1

Blank

*

0.1

0.08

0.1

0.08

0.1

10 0.3

ND

None detected.

17 5

ANP PROJECT QUARTERLY PROGRESS REPORT s i l i c o n c o n t e n t i n t h e r e s i d u e from c o r r o d e d I n c o n e l i s h i g h and i n d i c a t e s that practically a l l the silicon in t h e f u e l i s d e p o s i t e d on t h e w a l l s o f the container; the addition of zirconium h y d r i d e r e s u l t s i n t h e d e p o s i t i o n o f s o m e z i r c o n i u m on t h e c o n t a i n e r w a l l s ; and d e p o s i t i o n o f u r a n i u m d o e s n o t occur i n e i t h e r case.

P R E P A R A T I O N O F URANIUM T E T R A C H L O R I D E

U’. J . Ross Analytical Chemistry Division The p r e p a r a t i o n o f s e v e r a l k i l o g r a m s o f u r a n i u m t e t r a c h l o r i d e t o be u s e d i n p h a s e s t u d i e s by t h e A N P C h e m i s t r y Group has been undertaken.

The t e t r a c h l o r i d e i s b e i n g p r e p a r e d by c h l o r i n a t i n g UO, w i t h h e x a c h l o r o propene, according t o the d i r e c t i o n s g i v e n by P i t t e t ai.(’)

U n i a x i a l n e g a t i v e ( t e t r a g o n a l or h e x a g o n a l ) Refractive indices E , 1.652 0, 1 . 6 6 4 NaU,CI Ye 1 1 ow- green Biaxial n e g a t i v e (probably orthorhombic) with small o p t i c a n g l e Refractive indices a, 1 . 7 9 0 y , 1.850

UC1, -KC1 System.

T h e UC1, - K C l s y s t e m produced t h r e e compounds: 2KCl*UCl,, K C l . U C l , , and a n i n c o n g r u e n t l y m e l t i n g compound i n t h e 67% UCl, region of the binary.

T h e r e were two f o r m s t h a t c r y s t a l l i z e d i n t h e compoThey s i t i o n r a n g e o f 30% t o 35% UCl,. were d i s t i n g u i s h e d by t h e i r d i f f e r e n c e s i n b i r e f r i n g e n c e and i n t e r f e r e n c e figures.

PETROGRAPHIC EXAMINATION OF FLUORIDES

G. D. W h i t e , M e t a l l u r g y D i v i s i o n T. N . McVay, C o n s u l t a n t Routine petrographic examinations o f more t h a n 8 0 0 s a m p l e s o f f l u o r i d e m i x t u r e s were made i n c o n n e c t i o n w i t h fuel investigations.

Petrographic e x a m i n a t i o n s were made o f c o m p o s i t i o n s i n t h e UC14-NaC1 and U C l , - K C l s y s t e m s .

The d a t a o b t a i n e d from t h e s e examin a t i o n s were c o r r e l a t e d w i t h t h e t h e r m a l d a t a t o l o c a t e compound a n d e u t e c t i c compositions.

U C l , - N a C l System.

I n t h e UCI4-NaC1 b i n a r y s y s t e m , two compounds were f o u n d : 2NaC1-UC14, and a compound w i t h more t h a n 5 0 % UCI,, p o s s i b l y NaC1.2UC1,.

The l a t t e r compound seemed t o h a v e an incongruent melting point, since c o m p o s i t i o n s on t h e h i g h UC1, s i d e o f t h e b i n a r y always c o n t a i n c o n s i d e r a b l e amounts of f r e e UC1,.

Optical Data.

Na,UCI P a l e green t o c o l o r l e s s ( 7 ) B . M. P i t t e t a l . , T h e P r e p a r a t i o n of T C 1 , w i t h H e x a c h l o r o p r o p y l e n e , C - 2 . 3 5 0 . 3 (July 2 7 ,

1945).

17 6

Optical Data.

K,UCI 1. P a l e green t o c o l o r l e s s Uniaxial negative Refractive indices E , 1.644 0, 1.654

2 . P a l e green t o c o l o r l e s s B i a x i a l p o s i t i v e , small o p t i c a n g l e Refractive indices

a, 1.636 y , 1.640 KUCl PI eochroism X, grey 2, b l u e - g r e e n B i a x i a l p o s i t i v e , small o p t i c a n g l e Refractive indices a, 1.692 P, 1.705 y , 1.759 KU,CI Y e l l ow-green B i a x i a l p o s i t i v e , w i t h very small o p t i c a n g l e Refractive indices a, 1.740 P , 1.809 Y, 1 . 8 2 0

PERIOD ENDING MARCH 10, 1953 X - R A Y DIFFRACTION STUDIES P. A . Agron M a t e r i a l s Chemistry Division The d e t e r m i n a t i o n o f t h e p h a s e s p r e s e n t i n s o l i d i f i e d melts of various c o m p o s i t i o i i s i n t h e NaF-ZrF, -UF, s y s t e m has been h e l p f u l i n e l u c i d a t i n g t h e p a t h s o f c r y s t a l l i z a t i o n . The r e g i o n s o f t h i s t e r n a r y system t h a t a r e r i c h i n NaF h a v e b e e n e x a m i n e d d u r i n g t h e past quarter.

Some p r o g r e s s h a s b e e n made h e r e i n d e f i n i t i o n o f t h e t e r n a r y and pseudobinary phase regions.

The p e t r o g r a p h i c a n d x - r a y d i f f r a c t i o n i d e n t i f i c a t i o n of t h e phases found i n t h e s o l i d , upon m e l t i n g g i v e n c o m p o s i t i o i i s , a r e l i s t e d i n T a b l e 14.2.

The p h a s e s h a v e been g r o u p e d a c c o r d i n g t o the s i m i l a r i t i e s present i n the respective s o l i d i f i e d melts, thus A - 1 a n d A-2 r e p r e s e n t one t e r n a r y a r e a ; B-1 and B-2, t h e a d j a c e n t t e r n a r y area, etc. This d i v i s i o n i n t o ternary a r e a s i s :in f a i r a g r e e m e n t w i t h t h e isotherm(a1 c o n t o u r p l o t s ( t o be published), However, t h e anomalous s i t u a t i o n of f o u r phases i n samples B-1 a n d D - 2 o b v i o u s l y r e q u i r e s f u r t h e r investigation. Additional compositions o f t h e s e t e r n a r y a r e a s s h o u l d a l s o be i n v e s t i g a t e d b e f o r e mapping t h e p h a s e boundaries.

The e x a m i n a t i o n o f a number o f fused s o l i d s along the composition l i n e j o i n i n g NaUF, a n d Na3ZrF, a p p e a r s t o indicate a pseudobinary behavior.

A p p r o x i m a t e l y 90% o f t h e x - r a y d i f f r a c t i o n â&#x20AC;&#x2DC; p a t t e r n c a n be a s s i g n e d t o t h e s e two p h a s e s .

The c o o l i n g c u r v e s of a series of these compositions ( t o be p u b l i s h e d ) i n d i c a t e a b i n a r y e u t e c t i c a t a b o u t 22.5 m o l e % UF,.

The b e h a v i o r of s a l t s a l o n g t h e c o m p o s i t i o n l i n e b e t w e e n NaUFS a n d NaZrFs i s r a t h e r c o m p l e x beyond 6 mole % UF, c o n t e n t â&#x20AC;&#x2122; . ( 8 ) F u r t h e r s t u d y along t h i s composition l i n e , with the ( 6 ) p . A. A g r o n , X - r a y S t u d i e s o f P h a s e S e g r e g a t i o n i n P s e u d o NaZrFs-NaUF5 B i n a r y a s a F u n c t i o n o f H e a t T r e t r t m e n t ~n R a d l a t c o n S t u d i e s , O R N L CF-53-1-332 ( J a n . 20, 1953).

u s e of l i q u i d s a m p l i n g and q u e n c h i n g t e c h n i q u e s , w i l l be r e q u i r e d t o e x p l a i n t h i s a r e a o f t h e phase diagram.

SERVICE CHEMICAL ANALYSES

H. P. House

S. A . Reed A. F. R o e m e r , J r .

Analytical Chemistry Division Work i n t h e ANP A n a l y t i c a l C h e m i s t r y Laboratory during the period consisted primarily of the analysis of a l k a l i f l u o r i d e e u t e c t i c m i x t u r e s and z i r conium f u e l s .

A l t h o u g h t h e r e was a s l i g h t d e c r e a s e i n t h e t o t a l number o f samples received d u r i n g t h e q u a r t e r , t h e r e was a s i g n i f i c a n t i n c r e a s e i n t h e number o f m i s c e l l a n e o u s m a t e r i a l s received.

I m p o r t a n t among t h e s e was a g r o u p o f s a m p l e s t h a t were t e s t e d f o r beryllium content.

Included i n t h e group were l a r g e s t e e l s e c t i o n s o f t e s t r i g s used t o study t h e compatib i l i t y o f NaK a n d b e r y l l i u m o x i d e .

T h e s p e c i m e n s were f i r s t t r e a t e d w i t h m e t h a n o l t o remove e x c e s s NaK and t h e n l e a c h e d w i t h h o t , 50% s o d i u m h y d r o x i d e solutions t o dissolve the beryllium oxide adhering t o t h e s u r f a c e s of t h e specimens.

The b e r y l l i u m c o n t e n t o f t h e a l c o h o l i c and c a u s t i c s o l u t i o n s was d e t e r m i n e d c o l o r i m e t r i c a l l y , w i t h p-nitrobenzeneazo-orcinol a s t h e chromogenic r e a g e n t .

A number o f u r a n i u m t e t r a c h l o r i d e s a m p l e s w e r e a n a l y z e d f o r UO, a n d UOC1,.

S e p a r a t i o n o f UO, f r o m t h e s a l t was e f f e c t e d by r e f l u x i n g p o r t i o n s o f t h e m a t e r i a l w i t h d i l u t e ammonium oxalate solution.

T h e i n s o l u b l e UO, w a s removed by f i l t r a t i o n , d i s s o l v e d i n a c i d , and e s t i m a t e d q u a n t i t a t i v e l y by p o t e n t i o m e t r i c t i t r a t i o n w i t h f e r r i c sulfate.

The UOCl,, a l o n g w i t h any U O , , w a s s e p a r a t e d f r o m t h e UCl, by refluxing with anhydrous methyl acetate.

T h e i n s o l u b l e r e s i d u e was d i s s o l v e d i n d i l u t e n i t r i c a c i d , and t h e UOC1, w a s c a l c u l a t e d f r o m a volumetric determination of the c h l o r i d e con t e n t .

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PERIOD ENDING MARCH 1 0 , 1953 TABLE 14.3. SUMMARY OF SERVICE ANALYSES NUMBER OF

NUMBER OF

SAMPLES

REPORTED

DETERMINATIONS REPORTED

ANP Reactor Chemistry Group

508

4477

ANP Experimental E n g i n e e r i n g Group

216

2424

41

97

Heat T r a n s f e r and P h y s i c a l P r o p e r t i e s Group

6

86

E l e c t r o m a g n e t i c Research D i v i s i o n

2

15

11

114

784

7213

ADP P r o c e s s Improvement Group

General E l e c t r i c Company

I

-

Total

Comparative t e s t s of phenylarsonic a c i d and m a n d e l i c a c i d a s p r e c i p i t a n t s f o r z i r c o n i u m were c o m p l e t e d d u r i n g t h i s period.

S p e c t r o g r a p h i c examination of zirconium oxide residues r e s u l t i n g from t h e i g n i t i o n o f p r e c i p i t a t e s of phenylarsonic acid revealed t h e presence of s i g n i f i c a n t amounts o f a r s e n i c , a n t i m o n y , and iron, Z i rconium o x i d e from m a n d e l i c a c i d p r e c i p i t a t i o n s was f o u n d t o c o n t a i n only t r a c e s of s i l i c o n .

The u s e of mandelic a c i d a s t h e p r e c i p i t a n t r e s u l t e d i n much b e t t e r s e p a r a t i o n s from i n t e r f e r i n g i o n s a n d , i n a d d i t i o n , a considerable saving i n t i m e , By t h e use of t h i s reagent d u r i n g t h e l a t t e r p a r t of t h e q u a r t e r , amarked reduction i n t h e number o f d u p l i c a t e d e t e r m i n a t i o n s weis e f f e c t e d , a n d a c o n s i d e r a b l e increase i n t h e accuracy of t h i s d e t e r m i n a t i o n was a t t a i n e d .

Of t h e 7 8 4 s a m p l e s r e p o r t e d d u r i n g t h e p e r i o d , 65% were s u b m i t t e d by t h e ANP R e a c t o r C h e m i s t r y Group and 27% by t h e E x p e r i m e n t a l E n g i n e e r i n g Group.

O v e r 7 0 0 0 d e t e r m i n a t i o n s w e r e made d u r i n g t h e q u a r t e r , a f o u r t h o f which were made o n n o n r o u t i n e s a m p l e s .

S u m m a r i e s o f t h e ANP a n a l y t i c a l c h e m i s t r y work f o r t h e q u a r t e r a r e g i v e n i n T a b l e s 1 4 . 3 and 1 4 . 4 .

TABLE 14.4.

BACKLOG SUMMARY

S a m p l e s on h a n d ,

11-10-52

108

Number o f s a m p l e s r e c e i v e d

808

T o t a l number o f s a m p l e s

916

Number o f s a m p l e s r e p o r t e d

784

2-10-53

132

Backlog,

17 9

1 5 . LIST OF REPORTS I S S U E D DURING THE QUARTER TITLE OF REPORT

REPORT NO.

AUTHOR (S)

DATE ISSUED

I. General Design CF- 53-1-111

Minimum W e i g h t A n a l y s i s f o r a n A i r R a d i a t o r

W. S. Farmer

1-31-53

CF- 53-1-148

Component T e s t s Recommended t o P r o v i d e Sound B a s i s f o r Design of F l u o r i d e Fuel R e a c t o r s for Tactical Aircraft

A. P . F r a a s

1- 16-53

CF-53-2-159

ARE D e s i g n D a t a

W. B. C o t t r e l l

2-18-53

11. Experimental Engineering CF- 52-12-153 An I m p r o v e d AC E l e c t r o m a g n e t i c Pump C e l l

M. E. LaVerne

12-7-52

CF-53-1-84

ARE R e g u l a t i n g Rod

E. R. Mann S. H. Hanauer

1-9-53

CF- 53-1-260

Moore P r e s s u r e T r a n s m i t t e r T e s t Summary

P. W. T a y l o r

1-22-53

CF- 53-1-276

Components o f F l u o r i d e S y s t e m s

W. B. C o t t r e l l

1-27-53

ORNL- 1461

A S i m p l e E I e c t r o m a g n e t i c F l o w m e t e r for L i q u i d Metals

R. M. C a r r o l l

t o be i s s u e d

111. Reactor Physics

CF-53-1-64

D e l a y e d N e u t r o n Damping of N o n - L i n e a r R e a c t o r Oscillations

W. K. E r g e n

1-7-53

CF- 53-1-267

Delayed Neutron A c t i v i t y i n a C i r c u l a t i n g Fuel Reactor

H . L. F. E n l u n d

1-27-53

CF-53-1-317

D e l a y e d N e u t r o n A c t i v i t y i n t h e ARE F u e l E l e m e n t

H. L. F. E n l u n d

1-27-53

Y-881

A G r a p h i t e Moderated C r i t i c a l Assembly

E. L. Zimmerman

12-7-52

CF-53-2-50

The A t t e n u a t i o n o f C a p t u r e Gammas i n a P l a n e L i m i t e d Medium of F i n i t e T h i c k n e s s

F. A b e r n a t h y

2-6-53

CF- 53-2-99

H e a t i n g by F a s t N e u t r o n s i n a B a r y t e s C o n c r e t e S h i e 1d

F. A b e r n a t h y H. L. F. E n l u n d

2-11-53

O m - 1493

G e n e r a l Method o f R e a c t o r A n a l y s i s Used by ANP P h y s i c s Group

C. B. M i l l s

t o be i s s u e d

H. L. F. E n l u n d

IV. Metallurgy and Ceramics CF- 52-12-109

S p o t W e l d i n g of S t a i n l e s s C l a d F u e l E l e m e n t s

G. M. S l a u g h t e r

12-9-52

( n o number)

F o r m a b i l i t y a n d W e l d a b i l i t y o f Vapor-Deposi t e d Molybdenum. F i n a

Massachusetts I n s t i t u t e of Techno 1 ogy

10-31-52

MM- 54*

P r o g r e s s R e p o r t : The F1 as h We l d i n g o f Molybdenum.

Temperature D i s t r i b u t i o n During t h e Part I Flashing Cycle

Rensselaer Polytechnic I n s ti t u t e

12-5-52

CF-53-1-83

A H i g h - T e m p e r a t u r e C e r m e t Fuel E l e m e n t

J. E. J o h n s o n

1-9-53

CF- 53-2-79

C e r a m i c Fu

J. R. J o h n s o n

2-9-53

ORNL-1463

Methods of F a b r i c a t i o n o f C o n t r o l and S a f e t y E l e m e n t s f o r t h e ARE a n d HRE R e a c t o r s

J. H. Coobs E. S. Bomar

t o be i s s u e d

*

-

ement R a d i a t i o n T e s t s

Number assigned b y ANP R e p o r t s O f f i c e .

18 3

ANP PROJECT QUARTERLY PROGRESS REPORT REPORT NO.

ORNL- 149 1

T I T L E OF R E P O R T

AUTHOR (SI

L. S. R i c h a r d s o n D. C. V r e e l a n d W. D. Manly

C o r r o s i o n by Mol t e n F l u o r i d e s

DATE I S S U E D

t o be i s s u e d

V. Heat T r a n s f e r and P h y s i c a l P r o p e r t i e s a n d Momentum T r a n s f e r H. F. P o p p e n d i e k C h a r a c t e r i s t i c s o f t h e Two F l u o r i d e C o o l a n t s : ( L i F - 4 8 M%, BeF-52 M%) a n d (NaF-10 M%, KF-46 M%, ZrF,-44 M%)

11-29- 52

CF- 52- 11-20 5

E s t i m a t e s of Heat

CF- 52- 12- 124

Generalized Velocity D i s t r i b u t i o n f o r Turbulent Flow i n A n n u l i

W. B. H a r r i s o n J. 0. B r a d f u t e R. V. B a i l e y

12-19- 52

Y-B4-59

S e l e c t e d P h y s i c a l P r o p e r t i e s o f P o t a s s i u m and P o t a s s i u m H y d r o x i d e i n t h e T e m p e r a t u r e Range 1 0 0 t o 1000째C. A L i t e r a t u r e S e a r c h

R . L. C u r t i s

9-23-52

CF-53-1-233

Measurement o f t h e Thermal C o n d u c t i v i t y o f F l u o r i d e M i x t u r e s No. 1 4 a n d No. 30

S. J. C l a i b o r n e

1-8-53

CF- 53- 1-248

Remarks on t h e Fa1 I i n g - B a l I V i s c o m e t e r

R. F. Redmond S. I . K a p l a n

1-14- 53

CF- 53- 2- 56

H e a t C a p a c i t y of Fused S a l t M i x t u r e No. 3 0

W. D. Powers G. C. B l a l o c k

2-6-53

CF- 53- 2- 84

Heat Capacity of

W. D. Powers G. C. B l a l o c k

2-9-53

ORNL- 9 1 5

Forced Convection Heat T r a n s f e r i n Thermal Entrance Regions

W.

Vi.

B. H a r r i s o n

t o be i s s u e d

Shielding

11-18- 52

CF-52-11-129

Materials Research f o r Mobile Reactor S h i e l d i n g

E. P . B l i z a r d

CF-52-12-209

Thermal N e u t r o n Dose a t t h e Crew C o m p a r t m e n t

J . L. M e e m

CF- 53- 1 - 2 7 9

The Tower S h i e l d i n g F a c i l i t y

E. P. B l i z a r d

1-27-53

ORNL- 1438

E. B. J o h n s o n J . L. M e e m E. P. B l i z a r d

t o be i s s u e d

OWL- 1 4 7 1

D e t e r m i n a t i o n of t h e Power o f t h e Bulk S h i e l d i n g Reactor. P a r t 2 Shield Optimization

ORNL- 1479

A P r o t o n R e c o i l Type F a s t N e u t r o n S p e c t r o m e t e r

R. G. C o c h r a n K . M. Henry

t o be i s s u e d

t o be i s s u e d

VII. Chemistry ORNL- 1430

M o d i f i c a t i o n s o f t h e D i m e t h y l g l y o x i m e Method for t h e C o l o r i m e t r i c D e t e r m i n a t i o n o f N i c k e l B a s e d on t h e Use o f P o t a s s i u m P e r s u l f a t e a s t h e Oxidant

M. L. D r u s c h e l 0. Menis R. Rowan, Jr.

11-3- 52

Y- B3 1-3 90

A n a l y t i c a l Chemistry-ANP P r o g r a m Q u a r t e r l y P r o g r e s s R e p o r t f o r P e r i o d E n d i n g November 25, 1952

Analytical Chemistry D i v i s i on

11-20- 52

ORNL- 1 4 5 3

D i s s o l u t i o n o f NaK

J . C. White C. K. T a l b o t t L. J . Brady

12-2- 52

Y-B32-104

M i n u t e s o f Committee M e e t i n g f o r t h e C o o r d i n a t i o n o f Hydroxide Research, Fourth Meeting, December 10 a n d 11, 1952

F. K e r t e s z

1-7-53

184

1)

P E R I O D ENDING MARCH 1 0 , 1 9 5 3 REPORT NO.

T I T L E OF R E P O R T

Mass S p e c t r o m e t e r I n v e s t i g a t i o n o f UF,

L. 0. G i l p a t r i c k R u s s e l l Baldock J. R. S i t e s

8- 29- 52

ORNL- 1490

General Information Concerning F l u o r i d e s , A L i t e r a t u r e S e a r c h , S u p p l . t o ORNL-1252

M. E. Lee

t o be i s s u e d

ORNL- 1 4 9 5

General Information Concerning Hydroxides, A L i t e r a t u r e S e a r c h , S u p p l . t o ORNL-1291

M. E. Lee

t o be i s s u e d

Y-B32- 1 0 3

P o s s i b l e C o o l a n t s f o r S o l i d Fuel R e a c t o r s

W. R. G r i m e s

11-25-52

CF- 52- 12- 178

Hydroxide Systems

M. D. Banus

12-23-52

CF- 53- 1-129

Fused S a l t Compositions

C. J . B a r t o n

1- 1 5 - 5 3

O W -1 4 7 6

An I n d i r e c t C o l o r i m e t r i c Method f o r t h e D e t e r m i n a t i o n o f Uranium

J. C. W h i t e D. L. Manning

1- 13- 5 3

ORNL- 1500

Recovery o f Uranium as a S i n g l e P r o d u c t from Fluorides

C. F. Coleman

t o be i s s u e d

-

k

DATE I S S U E D

ORNL- 1376

VIII.

I -

AUTHOR (SI

Miscellaneous

Y- B3 1 40 3

A Guide f o r t h e S a f e H a n d l i n g o f Mol t e n F l u o r i d e s and H y d r o x i d e s

R e a c t o r Components S a f e t y Committee

1- 12- 53

ORNL- 1439

ANP P r o j e c t Q u a r t e r l y P r o g r e s s R e p o r t f o r P e r i o d E n d i n g December 1 0 , 1952

W. B. C o t t r e l I

1- 15- 5 3

CF- 53-2- 1 2 6

O b j e c t i v e a n d s t a t u s of ORNL-ANP R e a c t o r Program

R. C. B r i a n t

2- 13- 53

CF- 53- 2-246

ANP I n f o r m a t i o n M e e t i n g o f F e b r u a r y 18, 1953

W. B. C o t t r e l l

3-2-53

185

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