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OAK RIDGE NATIONAL LABORATORY

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Operated by UNION CARBIDE NUCLEAR COMPANY

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Division of Union Carbide Corporation

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CENTRAL FILES NUMBER

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Oak Ridge, Tennessee

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IF DATE: SUBJECT:

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COPY NO.

17/

Molten S a l t - G r a p h i t e Compatibility Test. R e s u l t s of P h y s i c a l and Chemical Measurements D i stribution

B. J. S h e i l , R. B. Evans, and G. 1. Watson 1

ABSTRACT The observed changes i n d i m e n s i o n s , weight, and chemical composition of nimpervious*i g r a p h i t e rods i n c o n t a c t for a year w i t h flowing l i q u i d LiF-BeF,UF4 (62-37-1 mole %I i n a pump loop a t 1360OF are l i s t e d . On t h e average t h e change in diameter was less than O.OZ%% and t h e change in weight was less than 0,03%. Chemiaal a n a l y s e s of machine c u t t i n g s from t h e g r a p h i t e rods show average uranium and beryllium c o n c e n t r a t i o n s of approximately 20 and 100 p p m respectively. \

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NOTICE T h i s document contoins information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge It i s subject to revision or correction National Loboratory. and therefore does not represent o final report. The information i s not to be abstracted, reprinted or otherwise given public ' dissemination without the approval of the ORNL patent branch, Legal and Information Control Department.


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MOLTEN SALT-GBAPHITE COMPATX~ILITY'PEST 1

RESULTS OF PHYSICAL

I

Apn,

CHEMICAt MEASUREMENTS

a

Q:

I n a g r a p h i t e moderated-molten s a l t r e a c t o r , c e r t a i n advantages a r e p o s s i b l e i f t h e g r a p h i t e is i n d i r e c t c o n t a c t with t h e c i r c u l a t i n g f l u i d . The f e a s i b i l i t y of such a design, which depends t o a l a r g e extent on the h m p a t i b i l i t y of t h e graphite-fused s a l t system, was t e s t e d by i n s e r t i n g 56 samples of an impervious g r a p h i t e contained by INOR-8 in a flowing stream of LiF-BeFZ-UF4 (62-37-1 mole %I â‚Ź o r a p e r i o d of one . year a t 136BOF.

-b

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The experimental assembly c o n s i s t e d of a pump l ~ o p c o n s t r u c t e d and operated by t h e Metallurgy Division and t h e Experimental Engineering s e c t i o n of t h e q e a c t o r P r o j e c t s Division a s described elsewhere, 1 Graphite Loop

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I n i t i a l Preparations

Two sets of g r a p h i t e specimens were obtained from t h e N a t i o n a l Carbon Company, A l l r o d s were 11" long and e i t h e r 112" o r 3/16" $n diameter. A f t e r c a l i p e r i n g and weighing, t h e rods were packaged i n an INOR-8 box a s shown i n Figures 1 and 2. Each of t h e l a r g e r was f i t t e d w i t h four spacing r i n g s t o permit t h e d e s i r e d flow c h a r a c t e r i s t i c s and t o provide samples f o r c a r b u r i z a t i o n and metallographic examination. c

"s, E

Upon welding t h e cover p l a t e i n place, t h e assembly was swaged in t h e loop and t h e g r a p h i t e degassed under vacuum for 24 h o u r s - a t 1lOOOF. I t was then repressured wwfth argon before being contacted with s a l t , During operation, a t o t a l p r e s s p e of 13 p s i g was maintained on t h e g r a p h i t e : 3 p s i g t h e c o n t r i bution of t h e helium cover blanket and t h e r e p a i n i n g due t o t h e head developed by t h e pump-rate of 1.1 gaS/min, When t h e test was compfeted, t h e s a l t was drained from t h e loop and sampled â‚Źor o p t i c a l microscopy, XZ-ray and w e t chemicql analyses,

1. .

J1 L, Crowley, ISR Quar, Prog. Repoy,January 31, 1958, ORNL-2474.

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The box c o n t a i n i n g t h e g r a p h i t e was opened by g r i n d i n g

off t h e top of the c o n t a i n e r i n t h e Y-12 Beryllium Shop.

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F i g u r e 3 is a photograph of t h e opened vessel a f t e r exposure t o molten f l u o r i d e s f o r one year a t 1300°F, P o s t T e s t Examinations

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A& S a l t Condition. The chemical a n a l y s i s , given i n Table I shows t h e chromium c o n t e n t of t h e s a l t increased from 135 ppm t o 550 ppm. Petrographic and X-ray analyses d i d 4 o t r e v e a l any oxidation products or dissolved carbon.

B,

Graphite Condition

1, Chemical Analyses Data, Machined increments of g r a p h i t e specimens were submitted for chemical analysiq. Successive c u t t i n g s , 1/32” i n depth w e r e taken from two of t h e l a r g e r diameter rods u n t i l c e n t e r p o r t i o n s of lees than 3/16m diameter were l e f t , These p o r t i o n s and ” a s received” impervious g r a p h i t e “blanks” were then ground t o -100 mesh i n a mortar and p e s t l e (thoroughly scoured w i t h Ottawa Sand according t o t h e recommendations of the A n a l y t i c a l Chemistry Division a f t e r ‘each grinding) A l l g r a p h i t e samples were submitted f o r an a n a l y s i s of t h e uranium and beryllitun codc e n t r a t i o n s . Two machine c u t t i n g s , l/?r2N i n depth, w e r e taken from f o u r a d d i t i o n a l rods. These r e s u l t s a r e given in Table I1 w i t h t h e b e r y l l i u m and c o n c e n t r a t i o n s graphed as a f u n c t i o n of p e n e t r a t i o n depth i n Figure 4. Only a v e r y s l i g h t migration o f s a l t t o t h e center of t h e g r a p h i t e is noted. 2. P h y s i c a l Changes i n Graphite. Macroscopically, there was no change in t h e rods, None of the samples w e r e broken OF d i s t o r t e d and except f o r t h e bottom l a y e r of rods t h a t was covered w i t h s o l i d i f i e d melt, t h e s a l t d i d n o t adhere t o t h e g r a p h i t e , The weight and dimensional changes obser-yed a f t e r they had been contacted w i t h c i r c u l a t i n g fIvrorides are l i s t e d i n Table 11~1, The dimensional changes f o r t h e 1$-1/2* diameter ro?s corresponded t o an average l o s s of less than 0.5 m i l i n diameter which approxima t h e probable e r r o r of t h e measurements, Otherwise, t h e r e no evidence of erosion. Ifeight l o s s e s , which ranged from n e g l i g i b l e t o 0.05% and averaged B.02$ could be a t t r i b u t e d t o d e s o r p t i o n of r e s i d u a l gases f r o m t h e graphite. o s t a t i s t i c a l l y significant differences were noted in t h e 1 I / Z h diameter r o d s as compared w i t h the 8-3/16w diameter rods r which weight d a t a w e r e a v a i l a b l e . e

Based on the l o s s i n weight of the test samples and t h e chemical a n a l y s e s of t h e machine c u t t i n g s , i t appears th’at a n l y minute q u a n t i t i e s of s a l t permeated t h e g r a p h i t e ,

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Table I Chemical Analyses of Fuel*

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It, % Be

U/Be

Charge

4.87

8.37

13.582

After operating 1 year

4.97

9.77

0,1509

* **

Theore t i c a l * * U/Be

6,767

G. JI Nessle, P e r s o n a l Communication. C a l c u l a t e d for LiF-BeFZ4JF4 (62-37-1 mole $1

.

PPM

Fe C r -Ni 235

135

5

330

555

25


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T a b l e I1 _

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A n a l y s e s of Machine C u t t i n g s f r o m G r a p h i t e Rods Rod

Cutting

No.

No,

11 14 23

18

.

*

2

1 2

22 10

125 110

1 2

24 28

75

0,320

105

0.267

17 <1 5

125 60 < I

0.017

8

< 1 170 1 30 1 25

1 2

* *

-

0.176 0.091

0,136 1

1

3 4 5

12 10

100

6

13

105

7 8

<I

50 1 40

165

0.03Q

* 1 2 3 4 5

4

13 5 <1 6 <1 100

1.000

IO5

0.057 1

0,800

< I 165

I? <I <1

.

< 1

5

8

9

65

20 18 24 29 20 20

7

140 12e 85

75 80

55 86 95

1

0,121 a.129 0.199 0.235 0,267

0.250 8,319 0.013 0 * 611..

el

4 1

1,009 .

11

el

Center

70

90 170

6.411

kQ

*

,

0.240 0.051

0.294 0 115 0,120 0, 120 0.154 6. 124 0 . 020 0.893

9 10 11 12* Center

w

.

0.573

50 15 15

2

.

Actual U/Be

125 175 < 1

1

31

Be

30 9 10

1

8 V

u

1 Theore t i c a 1 U/Be

PPM

*

c1

< 1

0.011 1

Samples machined from "as r e c e i v e d n m a t e r i a l . 1. Based on c h e m i c a l a n a l y s i s a t o r i g i n a l s a l t b a t c h , n o m i n a l l y LiF-BeF,-UFa (6Z-37-1 mole %)


Table 111

.

ImDervious GraDhi t e Rods ( 0 ,5'' diameter 1

V

r

Rod

No-

1 3

0

6 8 9

11 14 16 18 20 21

23 26 28 29 .31

B e f o r e Exposure Dia. Weight (gms) (in.)

A f t e r Exposure 'Weight Dia (gms? tin-)

Net Change

Percent

-0dsOlS8 -0,18133 '-0.0137 -0.0956

-0.02 -0002 -0 02 -0.01

0,495 0.497

-0.O184 -0.0133

02 -0.03 -0 02

0.500

-0.OO08 -0.0125 -0.0045 -0.Q14O -0.0174 -Q.022#

-0*03 -0.01 -0.02 -0.03 -0 a 04

0 Change,

Lost Lost 68.05B

68.0571 68.570 9 68,4152 68.7719 67.7389 68,2650 Lost 68.5801 67,9828 68.2956 68,6806 67 8522 67.9389

68.9397 68.0438 68.5572 68.4096 68,7639 67*7205 68.2517

0.498 0,498 0.502 0.509

0,499 0.496 0.498 0.500 0.497 0,499 p.501

0.499 00499

68.5793 67.9703 68.2911 1.68a4666 67.8352 67.9169

6,496 0'497 0.501 0.500 0050$1

0.496 0,50Q

8.501 0,498 0.498

0

-0

.

b

0,00

Impervious Graphite Rods ( 3/1bM diameter f

2

4 6 8 10 12 14 16 18

/r

9.1095 9.1236

9.1682 9.1228 9-4810 a* m52 9.3126 8.7372 9,fJSSO 9,5098 "3.81O4

9.4826

9.0329 9,3176 8.7251 9.0932 9.5142 9.0149

8

0

i

L+

7 3%

9

0013 -0.0012 -0.0016 +Om QbZl - O b

-0a005Q +0.0121

-0.0002

-8.81 -8. Q.1 -0.02

+a.oz

-0. Q5 +0*14 0.00 -0.05 -0.05


200

UNCLASSIFIED ORNL-LR-DWG-

41131A

I ROD 18

i60

120

.

1

80

-

40

-

0

-40 0 DEPTH

Fig.4. Penetration of on Impervious

732

732

5!32

(in.)

Graphite by LiF-BeF2-lJl$

.

16 /32


- 11 Distribution

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.* F

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i' t

A. 1. Weinberg

J. A. Swartout G. E. Boyd 4, R. A b Charpie 5 . W.,H, Jordan 6, R. B. Briggs 7. J. A. Lane 8. H. G. MacPherson 9. S. C. Lind 1Q. F, L, C u l l e r 11. W, R. G r i m e s 12. E, H, Taylor 131 A, Ls BOCh 14. E. G. Bohlman 15. M. A. Bredig 1 6 , F. R. B r u c e 17b A. Ph Fraas 18. W. D. Manly 19, H, F, McDuffie 20. A. J. Miller z1. c. F b Baes 22. C. J. Barton 23. I. Blander 24. F. F. Blqnkenship 25, 8 . E. Browning 26. S, Cantor 27. D, R. Cuneo 2 8 . R. B. Evans 29, H. I n s l e y 39. E. V. Jones 31. G. W. K e i l h o l t z 32, M. J, K e l l y 33, S. Langer 34, 8 . L. Marshall

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..

3 5 , . R. E, Moore G, J. Nessle R. F. Newton Lo G. Overholser . 38. 39. I. T. Rainey 40, J. E. S h a f f e r 41. M. D b Silverman 42, Be A. Soldano 43. R. A. Strehlow 44. R, E. Thoma 45. G. 1, Watson 46. L. G. Alexander 47. K, B. Brown 48, G. I, Cathers 49. J, H. DeVan 50, L. M. Doney 51. J. S, Drury 5 2 , D, E. Ferguson 53. Er Guth 54. E. E. Hoffman 5 5 . H, W. Hoffman 5 6 . B. W. Kinyon 5 7 . R. B. Lindauer 5 8 . W b B, McDonald . 5 9 . H. W. Savage 60. A. Taboada 61. D, B. Trauger 6 2 . P. H. E m e t t (Consultant) 63. D. G. H i l l (Consultant) 64-68, C e n t r a l Research W b r a r y 49-89, Laboratory Records Department 9 0 . Laboratory Records, ORNL K. C. 71. Reactor Experimental Eng. Library 92. ORNL Y-12 Technical L i b r a r y .

36. 37.

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