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Engineering Tests of the Metal Transfer Process for Extraction of Rare-Earth Fission Products from a Molten-Salt Breeder Reactor Fuel Salt H. C . Savage J. R. Hightower, Jr.

Printed in the United States of America. Available from National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road, Springfield, Virginia 22161 . Price: Printed Copy $4,50; Microfiche $3.00 This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the Energy Research and Development AdministratiodUnited States Nuclear Regulatory Commission, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibilityfor the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privatelyownedrights.

ORNL-5176 D i s t . C a t e g o r y UC-76

C o n t r a c t N o . W-7405-eng-26 CHEMICAL TECHNOLOGY DIVISION

ENGINEERING TESTS OF THE METAL TRANSFER PROCESS FOR EXTRACTION OF RARE-EARTH F I S S I O N PRODUCTS FROM A MOLTEN-SALT BREEDER REACTOR FUEL SALT

H . C . Savage J . R. H i g h t o w e r , Jr.

Date Published: February 1977

OAK ZIDGE NATIONAL LABORATORY Oak R i d g e , T e n n e s s e e operated by UNION CARBIDE CORPORATION for the ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION

TABLE OF CONTENTS

Page

............................ INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . METAL TRANSFER PROCESS . . . . . . . . . . . . . . . . . . DESCRIPTION OF METAL TRANSFER EXPERIMENTS MTE-3 AND MTE.3B . 3.1 Process Vessels and Equipment . . . . . . . . . . . . 3.2 Experimental Procedures . . . . . . . . . . . . . . . ANALYSIS OF DATA . . . . . . . . . . . . . . . . . . . . . EXPERIMENTAL RESULTS . . . . . . . . . . . . . . . . . . .

ABSTRACT

. 2. 3. 1

5.1

Overall Mass-Transfer C o e f f i c i e n t s and Equilibrium D i s t r i b u t i o n C o e f f i c i e n t s f o r Neodymium Entrainment S t u d i e s i n Experiment MTE-3B Neodymium and 147Nd Inventory i n Experiment MTE-3B Lithium Reductant i n t h e Bismuth S o l u t i o n s i n t h e Contactor and S t r i p p e r System Performance

....... ....... .. ................ 5.5 .................. 6 . DISCUSSION OF RESULTS . . . . . . . . . . . . . . . . . . . 7 . CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . 8 . ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . 9 . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 5.3 5.4

3 6

6 11 14

18 19 36 38

40 42 44

51 53 54 56

-1ENGINEERING TESTS OF THE METAL TRANSFER PROCESS FOR EXTRACTION OF RIIW-EARTH FISSION PRODUCTS FROM A MOLTEN-SALT BREEDER REACTOR FUEL SALT H. C. Savage J. R. Hightower, Jr.

ABSTRACT I n t h e metal t r a n s f e r process f o r removal of r a r e - e a r t h f i s s i o n products from t h e f u e l s a l t of a molten-salt breeder r e a c t o r (MSBR),the rare e a r t h s are e x t r a c t e d from t h e molten f u e l s a l t i n t o a molten bismuth s o l u t i o n c o n t a i n i n g l i t h i u m and thorium m e t a l r e d u c t a n t s , t r a n s f e r r e d from t h e bismuth i n t o molten l i t h i u m c h l o r i d e and, f i n a l l y , recovered from t h e l i t h i u m c h l o r i d e by e x t r a c t i o n i n t o molten bismuth c o n t a i n i n g l i t h i u m reductant. Engineering experiments using mechanically a g i t a t e d , nond i s p e r s i n g c o n t a c t o r s w i t h s a l t and bismuth flow rates [Q 1% of t h o s e required f o r processing t h e f u e l s a l t from a 1000-MW(e) MSBR] have been conducted (1) t o study t h i s process, (2) t o measure t h e removal rate of a r e p r e s e n t a t i v e r a r e - e a r t h f i s s i o n product (neodymium) from MSBR f u e l s a l t , and (3) t o e v a l u a t e t h e mechanically a g i t a t e d c o n t a c t o r f o r use i n a p l a n t processing f u e l s a l t from a 1000-MW(e) FISBR. The experimental equipment and procedures are described. R e s u l t s obtained during f i v e experiments i n which t h e rare e a r t h neodymium w a s e x t r a c t e d from MSBR f u e l s a l t are presented. Removal rates and mass-transfer c o e f f i c i e n t s between t h e s a l t and bismuth phases were determined f o r neodymium and are discussed i n terms of t h e processing requirements f o r a 1000-MW(e) MSBR.

1. INTRODUCTION The Oak Ridge National Laboratory h a s been engaged i n developing 232m-233u a molten-salt breeder r e a c t o r t h a t would o p e r a t e on t h e f u e l c y c l e t o produce low-cost power while producing more f i s s i l e

material than is consumed.

The r e a c t o r would u s e a molten f l u o r i d e

s a l t mixture as t h e f u e l and g r a p h i t e as t h e moderator.

I n order for

t h e r e a c t o r t o be operated as a breeder, i t would be necessary t o remove t h e r a r e - e a r t h f i s s i o n products on a 25- t o 100-day c y c l e and i s o l a t e 233Pa from t h e region of high neutron f l u x during i t s decay

-2t o 233U.

Thus

an o n - s i t e processing p l a n t t h a t contfnuously removes

t h e protactinium and rare e a r t h s i s required f o r t h e r e a c t o r t o perform as a breeder. The f u e l s a l t f o r a s i n g l e - f l u i d MSBR1 has t h e composition 71.6746-12-0.33

mole % LiF-BeF2-ThF4-UF4

r a r e - e a r t h f l u o r i d e f i s s i o n products.

and c o n t a i n s 233PaF

and 4 I n t h e r e f e r e n c e flowsheet

f o r t h e processing p l a n t , f u e l s a l t i s removed from t h e r e a c t o r a t

a rate of about 0.9 gpm.

The s a l t i s f i r s t fed t o a f l u o r i n a t o r

where-about 99% of t h e uranium is removed as UF6.

The s a l t stream

l e a v i n g t h e f l u o r i n a t o r i s contacted w i t h bismuth that c o n t a i n s l i t h i u m and thorium r e d u c t a n t s i n o r d e r t o e x t r a c t protactinium and t h e remaining uranium.

The s a l t stream, e s s e n t i a l l y f r e e of uranium

and protactinium but containing t h e r a r e - e a r t h f i s s i o n products, is then fed t o a r a r e - e a r t h removal system where t h e r a r e - e a r t h f i s s i o n products are e x t r a c t e d before r e t u r n i n g t h e f u e l s a l t t o t h e r e a c t o r . The equilibrium c o n c e n t r a t i o n of t h e rare e a r t h s i n t h e s a l t from t h e r e a c t o r i s . a b o u t 100 ppm f o r a 1000-MW(e) MSBR; r a r e - e a r t h ~

removal times range from 25 t o 100 days. Engineering experiments t o study a r e c e n t l y developed r a r e - e a r t h removal

c a l l e d t h e metal t r a n s f e r p r o c e s s , have been

conducted over t h e p a s t s e v e r a l years.

I n t h i s method, t h e rare e a r t h s

are e x t r a c t e d from t h e f u e l salt i n t o bismuth c o n t a i n i n g l i t h i u m and

thorium r e d u c t a n t s , t r a n s f e r r e d from the.bismuth i n t o molten l i t h i u m c h l o r i d e and, f i n a l l y , recovered from t h e l i t h i u m c h l o r i d e by e x t r a c t i o n i n t o molten bismuth c o n t a i n i n g l i t h i u m r e d u c t a n t . Mechanically a g i t a t e d salt-metal c o n t a c t o r s have been i n v e s t i g a t e d495 f o r use i n t h e MSBR processing systems based on r e d u c t i v e e x t r a c t i o n . This type of c o n t a c t o r is of p a r t i c u l a r i n t e r e s t f o r t h e metal t r a n s f e r process since adequate mass-transfer rates may be p o s s i b l e without d i s p e r s a l of t h e s a l t and bismuth phases.

Eliminating phase d i s p e r s a l

considerably reduces t h e problem of entrainment of bismuth i n t h e processed f u e l carrier s a l t and subsequent t r a n s f e r t o t h e r e a c t o r , which i s constructed of a nickel-base a l l o y t h a t i s s u b j e c t t o damage by metallic bismuth.

The bismuth i n t h i s type of c o n t a c t o r would be

a near-isothermal, i n t e r n a l l y c i r c u l a t e d , c a p t i v e phase t h a t would minimize t h e occurrence of mass-transfer corrosion.

Also, i t i s believed

t h a t a processing system employing t h i s type of c o n t a c t o r can be more e a s i l y f a b r i c a t e d of g r a p h i t e , which is required f o r bismuth containment, than one using packed columns. Operation and test r e s u l t s of engineering-scale experiments, u t i l i z i n g t h e metal t r a n s f e r process and mechanically a g i t a t e d c o n t a c t o r s ,

are described i n t h i s r e p o r t .

These experiments incorporated a l l t h e

s t e p s i n t h e metal t r a n s f e r process using s a l t flow rates t h a t were

about 1% of those r e q u i r e d f o r processing t h e f u e l s a l t from a 1000The g o a l s of t h e experiments were (1) t o study t h e v a r i o u s

MW(e) MSBR.

s t e p s of t h e process, (2) t o measure t h e rate of removal of r e p r e s e n t a t i v e r a r e - e a r t h f i s s i o n products from t h e molten-salt r e a c t o r f u e l , and (3) t o determine t h e s u i t a b i l i t y of mechanically a g i t a t e d c o n t a c t o r s f o r t h i s process.

For t h i s e v a l u a t i o n , mass-transfer c o e f f i c i e n t s between

t h e s a l t and metal phases i n t h e system w e r e determined using r e p r e s e n t a t i v e r a r e - e a r t h f i s s i o n products. 2.

METAL TRANSFER PROCESS

I n t h e metal t r a n s f e r process, f l u o r i d e f u e l s a l t t h a t - i s f r e e of uranium and protactinium is f i r s t contacted with molten bismuth c o n t a i n i n g l i t h i u m and thorium as r e d u c t a n t s a t concentrations of The rare e a r t h s are

about 0.002 and 0.0025 m.f.,

respectively.

e x t r a c t e d i n t o t h e bismuth.

The bismuth t h a t c o n t a i n s t h e rare e a r t h s

and thorium is then contacted w i t h molten l i t h i u m c h l o r i d e ; and, because of highly f a v o r a b l e d i s t r i b u t i o n c o e f f i c i e n t s , t h e rare e a r t h s d i s t r i b u t e s e l e c t i v e l y , r e l a t i v e t o thorium, i n t o t h e LiC1. The f i n a l s t e p of t h e process c o n s i s t s of e x t r a c t i n g t h e rare e a r t h s from t h e L i C l by c o n t a c t w i t h molten bismuth containing l i t h i u m r e d u c t a n t a t c o n c e n t r a t i o n s of 5 t o 50 a t . %. The chemical r e a c t i o n s t h a t r e p r e s e n t each s t e p of t h e process

are given below, using a t r i v a l e n t rare e a r t h as a n example: Reductive e x t r a c t i o n : Re3+(fuel salt) + 3Li(Bi) Bi--0*2

at' % Li+ 3Li+(fuel s a l t )

T r a n s f e r t o Li C1: RE(Bi)

+ 3Li+(LiC1)

LiCl

3Li(Bi)

+ RE3+

(LiC1);

(1) RE(Bi);

-4S t r i p p i n g i n t o Bi-Li: FS3+(LiC1)

+ 3Li(Bi)

(3) Bi--5

at' % Li

3Li+(LiC1)

+ RE(Bi).

The e q u i l i b r i a f o r t h e s e r e a c t i o n s have been measured and expressed

as d i s t r i b u t i o n c o e f f i c i e n t s f o r t h e rare e a r t h s between t h e f u e l carrier s a l t and bismuth c o n t a i n i n g l i t h i u m as a r e d u c t a n t and as d i s t r i b u t i o n c o e f f i c i e n t s of thorium and rare e a r t h s between l i t h i u m c h l o r i d e and bismuth containing l i t h i u m . y 7

The d i s t r i b u t i o n

c o e f f i c i e n t i s defined as

where

DM = d i s t r i b u t i o n c o e f f i c i e n t ,

5 = mole f r a c t i o n . o f metal M i n t h e bismuth phase, hn= mole f r a c t i o n of t h e metal h a l i d e i n t h e s a l t phase. Under c o n d i t i o n s of interest, t h e d i s t r i b u t i o n c o e f f i c i e n t s have been found t o be dependent on t h e l i t h i u m c o n c e n t r a t i o n s as follows: l o g DM = n l o g

si+ %,* log

(5)

where n = valence of metal Mn+ i n t h e s a l t phase,

= mole f r a c t i o n of l i t h i u m i n t h e bismuth phase,

$ = constant

a t a given temperature.

Calculated v a l u e s of rare earth--thorium

separation factors between t h e bismuth and L i C l s a l t range from about lo4 t o 108 f o r d i v a l e n t and t r i v a l e n t rare e a r t h s based on t h e measured d i s t r i b u t i o n coefficients. One v e r s i o n of a flowsheet f o r removing rare e a r t h s from MSBR f u e l s a l t using t h e metal t r a n s f e r process i s shown i n Fig. 1. Using t h i s method, uranium- and protactinium-free f u e l s a l t from t h e protactinium removal s t e p is fed t o a series of c o n t a c t o r s t a g e s thraugh which bismuth c o n t a i n i n g d i s s o l v e d r e d u c t a n t is c i r c u l a t e d . The bismuth i n each of t h e s e f u e l - s a l t c o n t a c t o r s t a g e s a l s o c i r c u l a t e s through a corresponding l i t h i u m c h l o r i d e c o n t a c t o r s t a g e w i t h i n a

series of c o n t a c t o r s through which a l i t h i u m c h l o r i d e stream flows. This l i t h i u m c h l o r i d e stream, i n t u r n , c i r c u l a t e s through a s i n g l e

ORNL

FROM

DWG

76-685

U, Pa-FREE SALT Pa-REMOVAL STEP

‘I f

“YDROFL~8RlNATOR

STRIPPER

BISMUTH -LITHIUM STRIPPER SOLUTION

PROC4ZES;$EfALT RECONSTITUTION STEP,

Fig.

Metal transfer

L. RECIRCULATING i ;SR$JTz

process using multiple

MTE-3--type

contactors.

-6c o n t a c t o r , where t h e l i t h i u m c h l o r i d e i s contacted w i t h a bismuthlithium stripper solution. An advantage of t h i s arrangement i s t h a t t h e f u e l salt--bismuth c o n t a c t o r s and t h e l i t h i u m chloride--bismuth

c o n t a c t o r s can be

constructed contiguous t o one a n o t h e r , and t h e bismuth can be made t o flow between t h e two by t h e pumping a c t i o n of t h e a g i t a t o r s (described Thus i n t h i s method, t h e

i n experiments MTE-3 and MTE-3B i n Sect. 3 ) .

need f o r e x t e r n a l bismuth pumps i s eliminated. Another advantage i s t h a t t h e bismuth i s t h i s t y p e of c o n t a c t o r would be a near-isothermal, c a p t i v e phase t h a t would minimize t h e occurrence of mass-transfer corrosion. Although o t h e r v a r i a t i o n s can be synthesized, t h e removal rates of neodymium measured i n experiment MTE-3B are discussed i n terms of

processing requirements f o r a 1000-MW(e) MSBR u s i n g t h e flowsheet shown i n Fig. 1. 3.

DESCRIPTION OF METAL TRANSFER EXPERIMENTS MTE-3 AND MTE-3B

3.1

Process Vessels and Equipment

The b a s i c equipment used i n t h e experiments (shown diagrammatically i n Fig. 2 ) , c o n s i s t e d of t h r e e carbon steel v e s s e l s : (1) a 14-in. (0.36-m)-diam f l u o r i d e s a l t r e s e r v o i r c o n t a i n i n g t h e f u e l carrier s a l t (72-16-12 mole % LiF-BeF2-ThF4),

metal c o n t a c t o r , and a 6-in.

a 10-in.

(0.25-m)diam

salt-

(0.15-m)-diam r a r e - e a r t h s t r i p p e r .

photograph of t h e process equipment i s shown i n Fig. 3.

The salt-

m e t a l c o n t a c t o r is divided i n t o two equal compartments by a carbon

steel p a r t i t i o n t h a t s e p a r a t e s t h e f l u o r i d e and L i C l salts. (13-mm)-high

A 1/2-in.

s l o t a t t h e bottom of t h e p a r t i t i o n i n t e r c o n n e c t s

t h e c a p t i v e pool of bismuth-lithium-thorium

solution i n t h e contactor.

Mechanical a g i t a t o r s i n both compartments of t h e c o n t a c t o r and i n t h e s t r i p p e r were used t o i m p r o v e c o n t a c t between t h e s a l t and bismuth phases.

Four-bladed t u r b i n e s , 2-7/8-in.

(73 mm) i n diameter and having

a p i t c h of 45", were located i n each phase. a g i t a t o r s i s shown i n Fig. 4.

A photograph of t h e

The blade mounting and s h a f t r o t a t i o n

w e r e such t h a t t h e s a l t and bismuth flows were d i r e c t e d toward t h e interface.

The engineering drawings used i n t h e c o n s t r u c t i o n of t h e

metal t r a n s f e r experiments are l i s t e d i n Table 1.

ORNL-DWG-71-147-RI

VENT

ARGON SUPPLY

LiF-BeFZ- ThFe FLUORIDE SALT RESERVOIR

SALT- METAL CONTACTOR

RARE EARTH STRIPPER

Flow diagram for metal transfer experiment MTE-3.

-8-

Fig. 3 .

Photograph of processing v e s s e l s for metal transfer experiment MTE-3B with heaters and thermocouples i n s t a l l e d .

Fig. 4.

Photograph of agitators used for promoting mass transfer between the s a l t and bismuth solutions i n metal transfer experiments MTE-3 and MTE-3B.

-10Table 1. Engineering drawings used i n c o n s t r u c t i o n of t h e m e t a l t r a n s f e r experiment Drawing number

Description

F-12172-CD-116E

Flowsheet

M-12172-CD-OZD

Fluoride s a l t tank

26D

Details of pump nozzle, viewing p o r t , s a l t funnel and d r a i n

27E

A g i t a t o r d e t a i l s of assembly

2 9E

Contactor vessel assembly

30E

Contactor v e s s e l p l a n view

31D

Contactor vessel s e c t i o n s

3 2E

Contactor vessel d e t a i l s h e e t 1

33D

Contactor vessel sampler d e t a i l s

34D

Thermowell d e t a i l s

35E

Acceptor vessel assembly

36D

Acceptor vessel s e c t i o n s A-A,

37D

Acceptor vessel d e t a i l s

38D

Transfer l i n e i s o l a t i o n f l a n g e assembly and d e t a i l s

39D

D e t a i l s f o r brazing copper s h e a t h t o steel p i p e

46D

Heat t r a n s f e r l i n e subassembly

47D

A g i t a t o r -blades assembly and d e t a i l s

48E

Vessel s t a n d and mounting d e t a i l s

49c

Samplers

51D

Details of s a l t t r a n s f e r l i n e piping

52E

F l u o r i d e s a l t pump assembly and d e t a i l s

53c

Sample l a d l e body d e t a i l

M-12053-CD-83C

S a l t and bismuth f i l t e r

B-B,

and C-C

c.i

-11The o u t s i d e s u r f a c e s of t h e carbon steel vessels were coated w i t h 'L

0.015-in.

(0.4-mm)-thick

chromium--nickel--6%

aluminum oxidation-

r e s i s t a n t material (METCO* No. P443-10) using a plasma spray gun.

This

prevented a i r o x i d a t i o n of t h e carbon steel vessels a t t h e o p e r a t i n g temperature of

923 K.

Fuel s a l t w a s c i r c u l a t e d between t h e f l u o r i d e s a l t r e s e r v o i r and one s i d e of t h e c o n t a c t o r by means of a s p e c i a l l y designed gas-operated pump u t i l i z i n g molten bismuth check valves.

Lithium c h l o r i d e w a s

c i r c u l a t e d between t h e s t r i p p e r and t h e o t h e r s i d e of t h e c o n t a c t o r by a l t e r n a t e l y p r e s s u r i z i n g and venting t h e s t r i p p e r vessel.

The bismuth

phase i n t h e c o n t a c t o r w a s c i r c u l a t e d between t h e two compartments in t h e c o n t a c t o r by t h e a c t i o n of t h e a g i t a t o r s , and no d i r e c t measurement of t h i s flow rate w a s made during experiments. However, measurements made i n

a mockup using a mercury-water system i n d i c a t e d t h a t t h e bismuth flow rate between t h e two compartments would be high enough t o cause t h e raree a r t h c o n c e n t r a t i o n s i n t h e compartments t o be e s s e n t i a l l y equal. 8 The s a l t flow rates used were about 1% of those required f o r processing t h e f u e l s a l t from a 1000-MW(e) MSBR. Approximate q u a n t i t i e s of s a l t and bismuth used i n t h e experiment

were t h e following: (1) 110 kg of f l u o r i d e s a l t and 64 kg of bismuthlithium-thorium (containing about 0.0018 atom f r a c t i o n l i t h i u m and 0.0014 atom f r a c t i o n thorium) i n t h e contactor, and (2) 1 0 kg of l i t h i u m c h l o r i d e and 44 kg of bismuth-lithium

(containing 0.05 atom f r a c t i o n

lithium) i n the s t r i p p e r .

3.2

Experimental Procedures

Procedures f o r t h e makeup, p u r i f i c a t i o n , and a d d i t i o n of t h e

s a l t and bismuth phases t o t h e process v e s s e l s were designed t o minimize contamination of t h e s e materials w i t h ' o x i d e ( a i r , water, and any oxides p r e s e n t i n t h e carbon steel process vessels).

P r i o r t o t h e a d d i t i o n of

t h e s a l t s and bismuth, t h e i n t e r n a l s u r f a c e s of a l l vessels were t r e a t e d w i t h hydrogen a t 923 K t o reduce r e s i d u a l i r o n oxides.

(Most of t h e s e

oxides had been removed by s a n d b l a s t i n g during f a b r i c a t i o n . )

After

t h i s treatment, a p u r i f i e d argon atmosphere (Q 0.1 ppm of H20) was maintained i n t h e vessels t o preclude f u r t h e r o x i d a t i o n . *METCO, Inc., 1101 Prospect Avenue, Westburg, Long I s l a n d , N.Y.

-12The s a l t and bismuth s o l u t i o n s were made up i n a u x i l i a r y vessels ( a l s o t r e a t e d w i t h hydrogen) a t hygrogen t r e a t e d a t

923 K t o remove oxides).

The bismuth w a s

923 K, while t h e f l u o r i d e s a l t and LiCl s a l t

were contacted w i t h bismuth containing thorium f o r oxide removal.

After

makeup and p u r i f i c a t i o n , a l l s o l u t i o n s were f i l t e r e d by passing through a s i n t e r e d molybdenum f i l t e r

('L

30-p pore-diameter) during t r a n s f e r

from t h e a u x i l i a r y vessels i n t o t h e process vessels.

A f t e r t h e process

v e s s e l s had been charged w i t h t h e s a l t and bismuth s o l u t i o n s , t h e e n t i r e system w a s maintained a t temperatures above t h e l i q u i d u s temperature

(1890 K)

of t h e s o l u t i o n s .

The experimental procedure w a s e s s e n t i a l l y t h e same f o r each run. The rare e a r t h f o r which t h e mass t r a n s f e r rate and o v e r a l l mass t r a n s f e r c o e f f i c i e n t s w e r e t o be measured was added t o t h e f l u o r i d e s a l t , t h e a g i t a t o r s were s t a r t e d and a d j u s t e d t o t h e d e s i r e d speed, c i r c u l a t i o n of t h e f l u o r i d e s a l t and L i C l w a s started, and t h e s a l t and bismuth phases

were p e r i o d i c a l l y sampled d u r i n g t h e run period and analyzed f o r rareI n each r u n , trace q u a n t i t i e s of a r a d i o a c t i v e i s o t o p e

e a r t h content.

wereincluded i n t h e r a r e - e a r t h a d d i t i o n , and counting of t h e radioa c t i v i t y of t h e samples w a s used t o f o l l o w t h e t r a n s f e r rate. ('L

Samples of t h e s a l t and bismuth phases were taken u s i n g a small 0.4-cm 3 ) s t a i n l e s s steel sampling capsule w i t h a s i n t e r e d metal

filter

20-p pore-diameter).

A 1/16-in.

(0.16-mm)-diam c a p i l l a r y

t u b e a t t a c h e d t o t h e c a p s u l e w a s used f o r i n s e r t i n g i t i n t o t h e s o l u t i o n t o be sampled ( s e e Fig. 5).

During i n s e r t i o n , t h e c a p s u l e w a s

continuously purged w i t h p u r i f i e d argon g a s u n t i l i t w a s p o s i t i o n e d i n the solution.

The flow of purge gas w a s then stopped, and a sample w a s

taken by applying a vacuum t o t h e capsule.

When t h e molten s a l t o r

bismuth s o l u t i o n reached t h e upper, c o o l s e c t i o n of t h e c a p i l l a r y tube, i t solidified.

The sample w a s t h e n withdrawn i n t o t h e sample p o r t and

allowed t o c o o l under a n argon atmosphere b e f o r e removal. A l l runs i n t h e second experiment, MTE-3B, were made using t h e rare e a r t h neodymium.

I n t h e s e r u n s , trace amounts ( 5 0 t o 150 m C i ) of 147Nd

were included i n t h e neodymiqm added t o t h e experiment.

Neodymium

c o n c e n t r a t i o n i n each phase was determined by counting t h e 0.53-MeV gamma emitted by t h e 147Nd i n t h e sample.

I n addition, t h e t o t a l .

neodymium c o n t e n t s of s e l e c t e d samples were determined by a n i s o t o p i c d i l u t i o n mass spectrometry technique.

This proved t o be a v a l u a b l e means

-13-

PLASTIC TUBING

-TO

ARGON AN0 VACUUM SUPPL IES

ORNL DWC NO. 72-10406

VENT 1/16 i n . STAINLESS STEEL CAPILLARY TUBING - 40 i n . LONG

3/16 i n . ORILL

OF VESSEL

1/4 i n . OlAM STAINLESS STEEL ROO

POROUS METAL FILTER, 20+ PORE S I Z E ,

SALT LEVEL

347 STAINLESS STEEL

- B 1 LEVEL

Fig. 5 .

Schematic diagram of sample capsule and sample port used i n experiment MTE-3B.

-14of checking on t h e tracer counting r e s u l t s and w a s e s p e c i a l l y u s e f u l f o r those samples w i t h v e r y low neodymium c o n c e n t r a t i o n s (< 1 ppm), where counting techniques were inadequate. For runs i n t h e i n i t i a l experiment MTE-3, i n which t h e rare e a r t h s europium, lanthanum, and neodymium were used, counting of t h e 1.28-MeV gamma emitted from t h e 154Eu tracer w a s used t o follow t h e t r a n s f e r

rate, and t h e lanthanum c o n c e n t r a t i o n w a s determined by neutron a c t i v a t i o n and subsequent counting of t h e 14'La

produced.

This r e p o r t p r i m a r i l y d e s c r i b e s t h e r e s u l t s obtained using t h e rare e a r t h neodymium i n t h e second m e t a l t r a n s f e r experiment, MTE-3B.

The

f i r s t experiment, MTE-3, was conducted by o t h e r s and r e p o r t e d r e s u l t s are summarized f o r comparison w i t h MTE-3B

previously ; results.

ANALYSIS OF DATA

Experiment MTE-3B involved t h e s u c c e s s i v e t r a n s f e r of rare e a r t h from a f l u o r i d e s a l t t o a bismuth-lithium-thorium pool, t o a l i t h i u m c h l o r i d e s a l t , and, u l t i m a t e l y , t o a bismuth-lithium pool.

The rate a t

which t h e rare e a r t h w a s t r a n s f e r r e d through t h e several c o n t a c t o r s t a g e s

w a s governed by t h e equilibrium d i s t r i b u t i o n c o e f f i c i e n t of t h e rare e a r t h , t h e s a l t and bismuth flow rates, and t h e mass-transfer coefficients.

The determination of t h e s e mass-transfer c o e f f i c i e n t s w a s

one of t h e major requirements f o r meeting t h e o b j e c t i v e s of t h e experiment.

An i d e a l i z e d s k e t c h of t h e c o n t a c t o r arrangement f o r t h e experiment is shown i n Fig. 6. From a r a r e - e a r t h material balance i n each of t h e seven regions i n d i c a t e d i n Fig. 6, t h e following equations governing t h e movement of

rare e a r t h through t h e regions were derived:

V3 dt dx3 = K 1A1(X 2

x3 DA

- F 2 ( ~ 3- ~ 4 1 ,

O R N L D W G 76-716

FLUOR1 SALT

J x6

-Li

Fig. 6 .

Idealized diagram of the metal transfer experiment showing the regions used for mass transfer calculations.

- Bi

-16-

dt = K3A3(X6 -

TIâ&#x20AC;&#x2122;

where t = time, s e c , x = molar concentration of rare e a r t h i n region i, i = 1,2,...7 i 3 Vi= volume of f l u i d i n region i, i = 1 , 2 , * . . 7 , c m ,

F1 = flow r a t e of f l u o r i d e s a l t , g-moles/sec, F2 = flow rate of bismuth between c o n t a c t o r compartments, g-moles/sec, F3 = flow rate of l i t h i u m c h l o r i d e between t h e s t r i p p e r and t h e c o n t a c t o r , g-moles/sec, DA = equilibrium d i s t r i b u t i o n c o e f f i c i e n t f o r t h e rare e a r t h

between f l u o r i d e s a l t and bismuth-lithium-thorium,

g-mole/g-mole,

DB = equilibrium d i s t r i b u t i o n c o e f f i c i e n t f o r t h e rare e a r t h between

bismuth-lithium-thorium and l i t h i u m c h l o r i d e , g-mole/g-mole, DC = equilibrium d i s t r i b u t i o n c o e f f i c i e n t f o r t h e rare e a r t h between

l i t h i u m c h l o r i d e and bismuth-lithium s t r i p p e r s o l u t i o n , g-mole/ g-mole, A1 = i n t e r f a c i a l area between f l u o r i d e s a l t and bismuth-lithiumthorium, cm 2 , A2 = i n t e r f a c i a l area between bismuth-lithium-thorium

and L i c l ,

cm 9 A3 = i n t e r f a c i a l area between L i C l and bismuth-lithium s t r i p p e r a l l o y , c m2 , K1 = o v e r a l l mass-transfer c o e f f i c i e n t a t t h e f l u o r i d e salt--

bismuth-lithium-thorium

i n t e r f a c e (based on c o n c e n t r a t i o n i n

t h e f l u o r i d e s a l t phase), cm/sec, K2 = o v e r a l l massLtransfer c o e f f i c i e n t a t t h e bismuth-lithium-

thorium-4iC1 i n t e r f a c e (based on c o n c e n t r a t i o n s i n t h e bismuth phase), cm/sec,

-17Kg = o v e r a l l mass-transfer c o e f f i c i e n t a t theLiC1--

bismuth-lithium i n t e r f a c e (based on concentrations i n t h e l i t h i u m c h l o r i d e phase), cm/sec. The o v e r a l l mass-transfer

c o e f f i c i e n t s are dependent on t h e

i n d i v i d u a l mass-transfer c o e f f i c i e n t s f o r each phase and t h e equilibrium d i s t r i b u t i o n c o e f f i c i e n t s f o r t h e rare e a r t h between t h e salt and bismuth They are expressed as follows:

solutions. -1 = - + +1-

K1 k2

k3DA

-1+ - , DB

-1= -

â&#x20AC;&#x2122;

+-,1 k7DC

where k2..-k7 = i n d i v i d u a l mass t r a n s f e r c o e f f i c i e n t s f o r each r e g i o n i n t h e c o n t a c t o r and s t r i p p e r vessels ( s u b s c r i p t s correspond t o t h e numbers assigned t o each phase i n Fig. 6). Overall mass-transfer c o e f f i c i e n t s f o r each run were c a l c u l a t e d by

s e l e c t i n g v a l u e s f o r K1,

K2, and K3 which r e s u l t e d i n t h e b e s t agreement

between c a l c u l a t e d time-dependent c o n c e n t r a t i o n s f o r each region and t h e experimentally measured time-dependent concentrations. The a p p r o p r i a t e known v a l u e s f o r t h e i n i t i a l c o n c e n t r a t i o n i n each

region, xi; the f l u i d volume of each region, Vi;

the area of each of the

t h r e e i n t e r f a c e s , AI, A2, and A3; and t h e t h r e e equilibrium d i s t r i b u t i o n c o e f f i c i e n t s , DA, DB, and DC were s u b s t i t u t e d i n t o Eqs. (6)-(12). estimates of K1,

Initial

K2, and K3 were a l s o s u b s t i t u t e d i n t o t h e s e equations,

which w e r e then solved using a computer program.

The c a l c u l a t e d r e s u l t s

were subsequently compared with t h e measured r e s u l t s , new estimates f o r K1,

K2, and Kg were chosen, and t h e s e were s u b s t i t u t e d i n t o t h e

d i f f e r e n t i a l Eqs. (6)-(12). v a l u e s f o r K1,

This process w a s repeated using a d j u s t e d

K2, and K3 u n t i l t h e c a l c u l a t e d r e s u l t s reproduced satis-

f a c t o r y measured r e s u l t s .

The v a l u e s f o r K l , K2, and K3 determined i n

t h i s manner w e r e taken as t h e experimentally p r e v a i l i n g o v e r a l l mass-

transfer coefficients.

-18 -

5. Four runs (Nd-1,

EXPERIMENTAL RESULTS

-2, -3,

and -4) u s i n g t h e rare e a r t h neodymium as

a r e p r e s e n t a t i v e f i s s i o n product were completed i n metal t r a n s f e r Neodymium w a s chosen as t h e r e p r e s e n t a t i v e rare-

experiment MTE-3B.

e a r t h f i s s i o n product f o r t h e s t u d i e s i n MTE-3B f o r several reasons: 1. Neodymium is one of t h e more important t r i v a l e n t f i s s i o n products t o be removed from a molten-salt breeder r e a c t o r f u e l salt. 2.

The u s e of 147Nd tracer w i t h i t s r e l a t i v e l y s h o r t h a l f - l i f e (11 days) would prevent excessive l e v e l s of r a d i o a c t i v i t y i n t h e experiment ( a d d i t i o n a l neodymium, containing 147Nd tracer, w a s added during t h e s t u d i e s ) .

R e s u l t s could be compared w i t h those obtained using neodymium i n t h e f i r s t experiment, MTE-3.

D a t a f r o m Nd--1, -3, and -4, w e r e analyzed, and o v e r a l l mass-transfer

c o e f f i c i e n t s a t t h e t h r e e salt-metal i n t e r f a c e s were determined.

Mass-

t r a n s f e r c o e f f i c i e n t s were n o t determined i n experiment Nd-2 due t o unexpected entrainment of f l u o r i d e s a l t i n t o t h e L i C l i n t h e c o n t a c t o r . Entrainment of f l u o r i d e s a l t i n t o t h e L i C l a f f e c t s t h e equilibrium d i s t r i b u t i o n c o e f f i c i e n t s of t h e rare e a r t h s and thorium between t h e L i C l and bismuth phases such t h a t thorium is t r a n s f e r r e d i n t o t h e LiC1.

Entrainment a l s o occurred during run Nd-1; however, t h e amount of f l u o r i d e s a l t entrained w a s r e l a t i v e l y s m a l l (Q 1.3 wt % F i n t h e L i C l ) , and t h e d i s t r i b u t i o n c o e f f i c i e n t s measured a t t h e end of r u n Nd-1 were n e a r t h e expected values.

During run Nd-2,

of f l u o r i d e s a l t entrained

t h e cumulative amount

3 wt %) became s i g n i f i c a n t .

The

d i s t r i b u t i o n c o e f f i c i e n t s ( p a r t i c u l a r l y f o r thorium a t t h e LiC1-bismuth i n t e r f a c e i n t h e contactor) were reduced, and a s i g n i f i c a n t q u a n t i t y of thorium w a s t r a n s f e r r e d i n t o t h e L i C l and w a s subsequently c i r c u l a t e d i n t o t h e s t r i p p e r , where i t r e a c t e d w i t h t h e l i t h i u m r e d u c t a n t i n t h e Bi-Li solution.

This r e a c t i o n continued u n t i l most of t h e l i t h i u m r e d u c t a n t

was l o s t from t h e s t r i p p e r and t h e neodymium was no longer e x t r a c t e d

i n t o t h e Li-Bi i n t h e s t r i p p e r ,

E x t r a c t i o n of neodymium stopped a f t e r

about 50 h r of o p e r a t i o n of run Nd-2; t r a n s f e r c o e f f i c i e n t s could be made.

t h u s no determination of mass-

-19Because of t h e entrainment of f l u o r i d e s a l t i n t o t h e L i C l during runs Nd-1 and Nd-2,

i t became necessary t o remove both t h e L i C l from t h e

c o n t a c t o r and s t r i p p e r and t h e bismuth--5 a f t e r run Nd-2.

a t . % L i from t h e s t r i p p e r

Fresh L i C l and bismuth-lithium s o l u t i o n were charged t o

t h e system b e f o r e s t a r t i n g r u n Nd-3. 5.1

Overall Mass-Transfer C o e f f i c i e n t s and Equilibrium D i s t r i b u t i o n C o e f f i c i e n t s f o r Neodymium

Operating c o n d i t i o n s and system parameters f o r r u n s Nd-1 through Nd-4 i n metal t r a n s f e r experiment MTE-3B are shown i n Table 2.

R e s u l t s of

t h e determinations of o v e r a l l mass-transfer c o e f f i c i e n t s f o r t h e rare e a r t h neodymium f o r runs Nd-1,

are given i n Table 3.

-3,

and -4 i n metal t r a n s f e r experiment MTE-3B

Values f o r t h e equilibrium d i s t r i b u t i o n

c o e f f i c i e n t s f o r neodymium measured a t t h e completion of each run, during p e r i o d s of no s a l t c i r c u l a t i o n , are shown i n Table 4. Previously r e p o r t e d v a l u e s f o r o v e r a l l mass-transfer c o e f f i c i e n t s f o r europium, lanthanium, and neodymium obtained i n t h e experiment, MTE-3,

are shown i n Table 5 f o r reference. Values f o r o v e r a l l mass-transfer c o e f f i c i e n t s f o r neodymium a t t h e t h r e e salt-bismuth i n t e r f a c e s i n metal t r a n s f e r experiment MTE-3B (Table 3)

were obtained by s e l e c t i n g v a l u e s f o r t h e mass-transfer c o e f f i c i e n t s which r e s u l t e d i n a "best f i t " between t h e experimentally obtained c o n c e n t r a t i o n s d u r i n g each run and t h e c a l c u l a t e d c o n c e n t r a t i o n s as discussed i n S e c t . 4. The experimentally measured v a l u e s f o r t h e equilibrium d i s t r i b u t i o n c o e f f i c i e n t s f o r neodymium between t h e s a l t and bismuth s o l u t i o n s w e r e used i n c a l c u l a t i n g t h e "best f i t " case. R e s u l t s are shown i n Figs. 8-18.

I n t h e s e f i g u r e s , t h e experimental

d a t a p o i n t s are i n d i c a t e d f o r each s o l u t i o n , and t h e l i n e shown r e p r e s e n t s t h e "best f i t " f o r t h e c a l c u l a t e d c o n c e n t r a t i o n s during each run.

Excellent

agreement w a s obtained f o r t h e f l u o r i d e s a l t s o l u t i o n and t h e bismuth--5

a t . % l i t h i u m s o l u t i o n i n t h e s t r i p p e r f o r each run.

For t h e s e s o l u t i o n s ,

t h e d a t a obtained by counting t h e 0.53-MeV gamma emitted by t h e 147Nd

tracer (with r e s u l t s expressed i n d i s i n t e g r a t i o n s p e r minute p e r gram) were used.

Equally good agreement w a s obtained f o r t h e d a t a obtained by

a n a l y s i s f o r t o t a l neodymium i n t h e s e two phases. by t o t a l neodymium a n a l y s i s (&g)

The r e s u l t s obtained

are shown f o r t h e bismuth-thorium-

l i t h i u m s o l u t i o n i n t h e c o n t a c t o r and t h e L i C l i n t h e c o n t a c t o r and s t r i p p e r .

-20-

T a b l e 2. Operating conditions f o r runs Nd-1 through Nd-4 i n m e t a l t r a n s f e r experiment MTE-3B

Run number Run t i m e , h r .

140a (l15.7>b

5.0

A g i t a t o r speed, r p s

138

165. 2a (107. 8Ib

5.0

4.17

1.67

Fluoride s a l t c i r c u l a t i o n rate, m3/sec

5.8 x

L i C l c i r c u l a t i o n rate, m3/sec

2.0

Average temperature, K

923

2.0

923

165a (109.5Ib

2.0

92 3

923

Q u a n t i t i e s of S a l t and Bismuth (g-moles) Fluoride f u e l s a l t i n reservoir

1535

Fluoride f u e l salt i n contactor

161

Bi-Li-Th i n f l u o r i d e s a l t compartment of contactord

132

129

132

.Bi-Li-Th i n L i C l s a l t compartment of contactor

161

156

101

132

114

190

L i C l i n contactor

LiCl i n stripper

Bi--5

at. % Li i n s t r i p p e r f

â&#x20AC;&#x2122;

a T o t a l t i m e of f l u o r i d e s a l t and/or L i C l s a l t c i r c u l a t i o n p l u s e q u i l i b r i u m t i m e with a g i t a t i o n but no s a l t c i r c u l a t i o n . bTime of f l u o r i d e s a l t and/or L i C l s a l t c i r c u l a t i o n . %ole w t = 42.4 g; p = 1.48 g/cm3; 1.1 = 0.016 P a t 923 K. 12

%ole w t = 63.2 g; p = 3.30 g/cm3; 1.1 = 0.0088 P a t 923 K. 13

eMole w t = 209 g; p = 9.66 g/cm3; 1.1 = 0.016 P a t 923 K. 14 fMole w t = 199 g; p = 9.28 g/cm 3 ; = 0.0094 P a t 923 K.

-21-

Table 3.

Overall mass-transfer c o e f f i c i e n t s a f o r neodymium i n metal t r a n s f e r experiment MTE-3B

Overall mass t r a n s f e r coe ff i c i e nt s (ma/ sec)b

Run number

Agitator speed (rps)

Run time (hr)

Nd-1

5.0

116

0.006

0.20

0.06

Nd-3

4.17

108

0.018

0.030

0.035

Nd-4

1.67

110

0.0040

0.020

0.0055

a The mass-transfer c o e f f i c i e n t s K1 and K3 are based on t h e r a r e - e a r t h concentration i n t h e s a l t phase, and K2 is based on t h e rare e a r t h conc e n t r a t i o n i n t h e bismuth phase. bDefined by Eqs. (13)-(15).

.. .

. . . .. . . . .

.-..-

. .

.. . ..

~..

. .- . . - ._.

. . ..

Table 4. Neodymium equilibrium distribution coefficientsayb Run number

DB Calculated Experimental

Calculated

Experimental

Calculated

Experimental

Nd-1'

0.03e

0.027

1.67e

0.94

3.5 x 104=

lo3

Nd-3'

0.017f.

0.022

0.9qf

0.98

3.5 x 104g

lo3

Nd-4'

0.017f

0.027

0.9qf

1.0

Eu-6, -7d

0.0088h

0.012

0.49

0.30

aCoefficients are defined as follows: neodymium in bismuth, m.f. neodymium in salt, m.f. b DAY DBY DC = equilibrium-distribution coefficients between phases (A) bismuth-thorium/fluoride salt, (B) bismuth-thorium/LiCl , (C) bismuth-5 at. % lithium/LiCl.

re h)

Experiment MT.E-3B.

dExperiment MTE-3. eBased on 60 ppm of lithium in bismuth. fBased on 50 ppm of lithium in bismuth. gBased on 5 at. % lithium in bismuth. hBased on 40 ppm of lithium in bismuth.

Table 5. Overall mass-transfer c o e f f i c i e n t s a f o r lanthanum, europium, and neodymium i n metal t r a n s f e r experiment MTE-3

Rare earth

Agi t a t or speed (rps)

La-1

2.50

La- 2

Eu-1

Run number

Eu-2, -3 Eu-4,

Eu-7,

15.2

0.0014

0.0011

0.12

3.33

15.4

0.002

0.0013

0.2

La Eu

1.67

14.3

0.0006 0.001

0.00039 0.000015

0.062 0.011

La Eu

3.33

15.0

0.002 0.003

0.0013 0.000048

0.2 0 033

3.33

12.2

0.002

0.020

0.2

La Nd

3.33

64.6

0.002 0.002

0.020 0.065

0.2 0.2

La Nd

5 .O

15.4

0.0026 0.0032

0.032 0.11

0.2 0.2

-5

Eu-6 -8 '

Overall mass t r a n s f e r c o e f f i c i e n t (mm/sec)

a The mass-transfer c o e f f i c i e n t s K 1 and K are based on t h e r a r e - e a r t h c o n c e n t r a t i o n i n t h e s a l t phase, and K2 i s based on t h e r a r e - e a r t h concentra&on i n t h e bismuth phase.

bSee f o o t n o t e (b) i n Table 3. C

A f t e r argon sparging i n t h e L i C l s i d e of c o n t a c t o r (bismuth-thorium/LiCl phases, K2).

ORNL D W G 7 6 - 8 7 8

2.0

I .5

1.0 0 0-

0.5 t

-RESERVOIR A CONTACTOR 0

F i g . 7.

60 80 TIME (hr)

I00

Neodymium concentration i n the fluoride s a l t i n the reservoir and contactor during run Nd-1.

c O R N L O W 0 76-884

L i C l IN THE CONTACTOR L i C l I N THE S T R I P P E R 7

t OO

STOPPED FLUORIDE SALT CIRCULATION

STOPPED LiCl CIRCULATION

20 F i g . 8.

= CONTACTOR = STRIPPER

60 80 RUN T I M E (hr)

I00

Neodymium concentration i n the L i C l i n the contactor and stripper during run Nd-1.

120

0.4Q

. . .. .

. ...

~. .

ORNL O W 0 76-882

? Q,

0.30

' I

STOPPED FLUORIDE

0 t-

STOPPED

p: I-

z 0.20 w 0

0 0

-I3 0.10 t c3

z O,

J A a

A A

20 Fig. 9.

@ = F L U O R I D E SALT S I D E OF CONTACTOR ~ s L i C lSIDE O F CONTACTOR I I 1 I I 40 60 80 I00 120 RUN TIME (ht)

I h)

Neodymium concentration i n the bismuth-thorium i n the contactor during run Nd-1.

-27-

ORNL O W 0 76-899

5.0

4.0

3.0

2.0

1.0

TIME (hr) Fig. 10.

Neodymium concentration i n the bismuth-5 at. % lithium i n the s t r i p p e r during run Nd-1.

ORNL DWG 76-350 5.0

STOPPED FLUORIDE -SALT CIRCULATION

4.0

STOPPED Li Cl CIRCULATION

3.0

2.0

I ,o

TIME ( hr ) Fig.

11.

Neodymium concentration in the fluoride contactor during run Nd-3, MTE-3B.

salt

in the

ORNL

0.5

DWG

?c)-884

STOPPED LiCl CIRCULATION

0.2

STObPED

FL%l!YDE

CIRCULATION

A 0

0.1 -

I 20

Fig.

. * FLUORIDE or * LiCl SIDE I 40

12.

I 60

SALT

I 80 RUN

SIDE

I 100 TIME (hr)

I 120

Neodymium concentration in the bismuth-thorium the contactor during run Nd-3.

I 140

solution

I 160

ORNL D W G 76-911

2.5 a = CONTACTOR A = STRIPPER

2.0 STOPPED F L U O R I D E SALT CIRCULATION

STOPPED LiCl C IRC U L A T IO N

0.5

20 Fig. 13.

I 40

I I 80 100 120 R U N TIME ( h r )

140

160

Neodymium concentration i n the LiCl in the contactor and stripper during run Nd-3.

180

ORNL DWG 76-351 4.07

STOPPED FLUORIDE 3.0 - - SALT CIRCULATION

I 0

(

I 60

STOPPED LiCl CIRCULATION

I 80

I 100

I 120

140

TIME (hr) Fig.

14.

2.0 -

Neodymium concentration in the bismuth-5 the stripper during run Nd-3, MTE-3B.

at.

% lithium

I 160

ORNL DWG 760352Rl

5.0

4.0 -

STOPPED Li Cl CIRCULATION

STOPPED FLUORIDE SALT CIRCULATION

3.0

2.0 -

I .o

) -

I 40

I 60

100

I 120

140

TIME (hr) Fig.

15.

Neodymium concentration in the fluoride during run Nd-4, MTE-3B.

salt

in the contactor

160

0.5 b \ D

g 2

0.4

0.3

0.2

i t

FLUORIDE SALT SIDE CI SIDE

A 0

A I

sz 0. I

0 0

A = Ll

STOPPED L l C l SALT CIRCULATION 0

STOPPED FLUORIDE SAL7 CIRCULATION

100 RUN TIME

120

I40

160

(hr)

Fig. 16. Neodymium concentration in the bismuth-thorium in the contactor during run Nd-4.

180

ORNL O W 0 7 6 - 8 9 6

2.0 =CONTACTOR A =STRIPPER

S T O P P E D FLUORIDE SALT CIRCULATION

1.5

u 1.0 I*

o W

2o m

STOPPED L i C l C I R C UL AT ION

0.5

e A A

I 20

I 40

I 60

I 80

100

I 120

140

160

R U N T I M E (hr)

Fig. 1 7 .

Neodymium concentration i n the L i C l i n the contactor and stripper, run Nd-4.

1 80

ORNL DWG 76-353RI

5.0

I .I

4.0

3.0

2.0 STOPPED FLUORIDE -SALT CIRCULATION

STOPPED Li Cl CIRCULATION

1.0

120

I00

140

TIME (hr) Fig.'18.

Neodymium concentration in the bismuth-5 stripper during run Nd-4, MTE-3B.

at.

% lithium

in the

160

, -3 6More s c a t t e r and fewer p o i n t s appear i n t h e s e d a t a .

However, i t i s f e l t

t h a t t h e f i g u r e s f o r t h e t o t a l neodymium content more n e a r l y r e p r e s e n t t h e t r u e c o n c e n t r a t i o n i n t h e s e s o l u t i o n s s i n c e t h e r e s u l t s obtained by t h e counting of samples from t h e s e s o l u t i o n s were u n r e a l i s t i c a l l y high (by a The d i f f i c u l t y seemed t o be a b i a s i n t h e counting d a t a

f a c t o r of 3 ) .

a t t h e s e very low neodymium c o n c e n t r a t i o n s (< 1 ppm). Tabulations of t h e concentrations of 147Nd t r a c e r and t h e t o t a l neodymium f o r a l l samples removed during r u n s Nd-1 through Nd-4 are included i n t h e Appendix. 5.2

Entrainment S t u d i e s i n Experiment MTE-3B

Based on previous s t u d i e s i n -awater-mercury system,15 i t w a s concluded t h a t entrainment of f l u o r i d e s a l t i n t o t h e bismuth and L i C l phases i n t h e mechanically a g i t a t e d c o n t a c t o r would occur i f t h e a g i t a t o r s w e r e operated a t speeds of 5.0 r p s o r higher.

However, i n t h e f i r s t metal

t r a n s f e r experiment, MTE-3, entrainment w a s not observed a t 5.0 r p s but w a s seen a t 6.7 r p s . 16 Since f l u o r i d e s a l t entrainment occurred a t a n a g i t a t o r speed of 5.0 r p s i n experiment MTE-3B, a series of tests were made t o determine t h e

maximum allowable a g i t a t o r speed t h a t could be used i n experiment MTE-3B without entrainment.

The tests were conducted by o p e r a t i n g t h e a g i t a t o r s

i n t h e c o n t a c t o r a t s e v e r a l d i f f e r e n t s p e e d s (3.3, 4.6, and 5.0 r p s ) f o r

time p e r i o d s ranging from

50 t o

140 hr. During each test a t

c o n s t a n t a g i t a t o r speeds, samples of t h e L i C l salt w e r e removed from t h e c o n t a c t o r and analyzed f o r f l u o r i d e content.

An i n c r e a s e i n f l u o r i d e i o n

c o n c e n t r a t i o n would i n d i c a t e entrainment of f l u o r i d e s a l t i n t o t h e L i C 1 . Figure 19 shows t h e f l u o r i d e i o n Concentration i n t h e L i C l as a f u n c t i o n of time f o r each a g i t a t o r speed. i o n of

The i n i t i a l c o n c e n t r a t i o n of f l u o r i d e

4 w t % r e p r e s e n t s t h e amount of entrainment t h a t occurred over

a period of

250 h r during r u n s Nd-1 and Nd-2.

The sequence of a g i t a t o r

speeds shown i n F i g . 1 9 r e p r e s e n t s t h e o r d e r i n which t h e tests were run. An i n c r e a s e i n t h e f l u o r i d e i o n c o n c e n t r a t i o n is c l e a r l y i n d i c a t e d i n t h e 'L

50-hr test a t 5.0 r p s .

A t a g i t a t o r speeds of 3.3 and 4.6 r p s , no

entrainment (within experimental l i m i t s ) appears t o have occurred over t h e 'L

200-hr combined test p e r i o d s a t t h e s e two speeds.

ORNL DWG 76-349Rl

4 +

5.Orps-rcr I 40

3.3 rps -+â&#x20AC;&#x2DC;pI 80

4.6rps I 120

I 160

200

240

TIME (hr) Fig. .19.

Results of tests to determine the entrainment rate of fluoride salt into LiCl as a function of agitator speed, MTE-3B.

280

-38These r e s u l t s i n d i c a t e d t h a t experiments cauld be c a r r i e d o u t a t a g i t a t o r speeds up t o about 4.5 r p s without entrainment,and experiments

Nd-3 and Nd-4 were conducted u s i n g a g i t a t o r speeds of 4.2 and 1.67 r p s . It w a s a l s o concluded t h a t r a p i d determinations of f l u o r i d e i o n c o n c e n t r a t i o n

i n t h e L i C l duringexperimen:ts were needed t o v e r i f y t h a t no entrainment w a s occurring.

For t h i s purpose, an Orion Model 801A pH/mV meter* equipped w i t h

s p e c i f i c i o n ( f l u o r i d e ) e l e c t r o d e s was obtained f o r r a p i d analyses of L i C l samples. The mV meter could a l s o be used t o continuously measure and record t h e emf between t h e two bismuth phases i n t h e c o n t a c t o r and s t r i p p e r vessels t h a t contained d i f f e r e n t c o n c e n t r a t i o n s of l i t h i u m r e d u c t a n t (0.0015 and 0.050 atom f r a c t i o n l i t h i u m ) .

A change i n emf would

i n d i c a t e a change i n t h e l i t h i u m c o n c e n t r a t i o n r a t i o i n t h e s e phases (Sect. 5.3) w i t h a r e s u l t a n t change i n t h e equilibrium d i s t r i b u t i o n c o e f f i c i e n t f o r neodymium and thorium between t h e s a l t and bismuth phases. 5.3

Neodymium and 147Nd Inventory i n Experiment MTE-3B

Weighed amounts of neodymium, as NdF3, c o n t a i n i n g 147Nd tracer w e r e added t o t h e f l u o r i d e f u e l s a l t i n t h e f u e l s a l t r e s e r v o i r on t h r e e occasions during o p e r a t i o n of m e t a l t r a n s f e r experiment MTE-3B.

The NdF3

and 147Nd tracer were prepared by t h e I s o t o p e s D i v i s i o n of ORNL.

The

NdF3 containing t h e tracer w a s placed i n a s p e c i a l l y designed charging capsule used t o add t h e neodymium t o t h e f u e l s a l t (Fig. 20).

The

capsule w a s s e a l e d by a spring-loaded d i s c which w a s soldered t o t h e capsule.

When i n s e r t e d i n t o t h e molten f u e l s a l t (Q923 K ) , t h e s o l d e r

melted and opened t h e capsule, allowing t h e NdF3 t o d i s p e r s e i n t o t h e f u e l salt.

Capsules w e r e i n s p e c t e d a f t e r each a d d i t i o n t o ensure t h a t

a l l of t h e neodymium had been t r a n s f e r r e d i n t o t h e f u e l s a l t . 147Nd and t o t a l neodymium inventory during each run i n metal t r a n s f e r experiment MTE-3B w a s followed by both counting and chemical a n a l y s e s of samples of t h e s a l t and bismuth phases.

The c o n c e n t r a t i o n of

147Nd w a s determined by counting t h e 0.53-MeV gamma emitted, while t h e concentration of t h e t o t a l neodymium w a s determined by a n i s o t o p i c d i l u t i o n mass-spectrometry technique. *Orion Research, Inc., Cambridge, Mass.

-39-

O R N L D W G 76-874

- 0. D. x 0.028 WALL 316 STAINLESS STEEL TUBING WELD TUBE TO CAP

ALL DIMENSIONS IN INCHES

STAINLESS STEEL SINTERED METAL FILTER

STAINLESS STEEL SPRING IN COMPRESSION

WELD SPRING TO TUBE WALL AND DISC

Fig. 20.

'-THICK CARBON STEEL DISC. 2 SOLDER TO TUBE USING S O - 5 0 LEAD-TIN SOFT SOLDER

Capsule used to add neodymium containing 147Nd tracer t o the f u e l s a l t i n experiment MTE-3B.

-4 0Table 6 compares t h e neodymium and 147Nd inventory i n metal t r a n s f e r experiment MTE-3B based on t h e amounts added t o t h e system and those c a l c u l a t e d from t h e c o n c e n t r a t i o n s i n a l l phases determined by sampling.

As seen i n Table 6, t h e inventory of neodymium and 147Nd tracer

determined by sampling was'in good agreement w i t h t h e amounts added, varying between 84 and 100% f o r each of t h e f o u r runs. These r e s u l t s i n d i c a t e t h a t (1) t h e l o s s e s of neodymium were i n s i g n i f i c a n t , (2) t h e neodymium remained d i s p e r s e d i n t h e s a l t and bismuth s o l u t i o n s , and (3) t h e sampling procedures provided samples t h a t adequately represented t h e c o n c e n t r a t i o n s of neodymium in t h e s a l t and bismuth solutions. 5.4

Lithium Reductant i n t h e Bismuth S o l u t i o n s i n t h e Contactor and S t r i p p e r

The equilibrium d i s t r i b u t i o n c o e f f i c i e n t s f o r neodymium (and o t h e r rare e a r t h s ) between t h e s a l t and bismuth s o l u t i o n s i n t h e m e t a l t r a n s f e r

process are dependent on t h e l i t h i u m r e d u c t a n t c o n c e n t r a t i o n s i n t h e bismuth s o l u t i o n s (Sect. 2).

Therefore, mass-transfer c o e f f i c i e n t s f o r

t h e rare e a r t h s are dependent on t h e s e equilibrium d i s t r i b u t i o n coefficients. During t h e runs i n experiment MTE-3B,

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

r e d u c t a n t i n t h e bismuth s o l u t i o n s were known i n i t i a l l y .

The relative

c o n c e n t r a t i o n s of l i t h i u m i n t h e bismuth i n t h e c o n t a c t o r (Q 0.0015 m.f.) and i n t h e s t r i p p e r (Q 0.05 m.f.)

were determined during t h e experiments

by measuring t h e emf between t h e s e two bismuth s o l u t i o n s .

The c o n t a c t o r

and s t r i p p e r v e s s e l s are e l e c t r i c a l l y i s o l a t e d from each o t h e r by an e l e c t r i c a l l y i n s u l a t e d " i s o l a t i o n f l a n g e , I ' and t h e bismuth s o l u t i o n s

are connected by t h e molten L i C l t h a t circulates between t h e c o n t a c t o r and s t r i p p e r .

The relative c o n c e n t r a t i o n s of l i t h i u m i n t h e bismuth

s o l u t i o n s can be c a l c u l a t e d from t h e emf measurement by t h e following 17 equation : emf = -RT/nF I n C1/C2,

(16)

where emf = emf developed between t h e two s o l u t i o n s , V, n = valence, R = gas c o n s t a n t = 1.987 cal/mole*K, F = Faraday = 23,050 cal

f1(g-equiv)

-1

Table 6.

Neodymium and 147Nd inventory and mass balance i n metal t r a n s f e r experiment MTE-3B

Nd by sampling Nd added T o t a l Nd Nd-14 1 Start md Start Fnd ~~~~~~

Nd added t o system Nd Nd-147

Nd determined by sampling T o t a l Nd (21Nd-147 (mci) Start End

,e",

2.24

71.4

2.10

2.11

63.1

59.9

93.7

94.2

88.4

83.9

4.61

83.5

4.10a

73.0a

88.9

87.4

5.91

148.9

4.98

5.03

144.1

84.3

85.1

96.8

5.91

148.9

5.12

5.32

150.9

131.5

86.6

90.0

100.3

88.3

%rial

inventory n o t determined due t o f l u o r i d e s a l t entrainment.

I P

C1,

C2 = concentration's of l i t h i u m i n t h e two bismuth s o l u t i o n s .

For t h e c o n c e n t r a t i o n s of l i t h i u m r e d u c t a n t i n t h e bismuth phases i n experiments conducted i n MTE-3B, t h e expected emf w a s

275 mV.

Measurements of emf taken i n t e r m i t t e n t l y during r u n s Nd-1 and Nd-2 gradually decreased from

300 mV t o

25 mV n e a r t h e end of run Nd-2,

i n d i c a t i n g l o s s of l i t h i u m reductant i n t h e s t r i p p e r (see Table 7). (This l o s s of l i t h i u m i n t h e s t r i p p e r w a s caused by t h e entrainment of f l u o r i d e f u e l s a l t i n t o t h e L i C l and by subsequent r e a c t i o n of t h e

It r e s u l t e d i n no f u r t h e r

thorium i n t h e f u e l s a l t w i t h t h e l i t h i u m . e x t r a c t i o n of neodymium as w a s observed.)

I n t h e f i n a l two experiments, Nd-3 and Nd-4,

t h e emf between t h e

c o n t a c t o r and s t r i p p e r w a s followed continuously by using a recording millivolt-meter.

No entrainment of f l u o r i d e f u e l s a l t occurred during

t h e s e runs,and t h e emf between t h e bismuth s o l u t i o n s remained e s s e n t i a l l y constant a t

250 mV, i n d i c a t i n g no s i g n i f i c a n t change i n t h e

c o n c e n t r a t i o n s of l i t h i u m r e d u c t a n t .

5.5

System Performance

I n s t a l l a t i o n of metal t r a n s f e r experiment MTE-3B w a s e s s e n t i a l l y complete i n February 1975.

During March 1975, t h e process v e s s e l s w e r e

p r e s s u r e t e s t e d (both a t room temperature and a t an o p e r a t i n g temperature of

923 K); and t h e i n t e r n a l s u r f a c e s of t h e process vessels and

charging vessels w e r e hydrogen t r e a t e d a t oxides.

923 K t o remove r e s i d u a l

A f t e r t h e hydrogen treatment, a l l v e s s e l s w e r e maintained under

p u r i f i e d argon (Q 0.1 ppm of H20) t o prevent o x i d a t i o n .

The a d d i t i o n of

a l l s a l t and bismuth s o l u t i o n s t o t h e p r o c e s s vessels w a s completed during May 1975 w i t h t h e system a t t h e o p e r a t i n g temperature of

923 K.

The i n i t i a l experiments (Nd-1 and Nd-2) were c a r r i e d o u t i n June 1975, and, a f t e r removal of t h e L i C l from t h e c o n t a c t o r and s t r i p p e r and t h e removal of t h e bismuth--5 L i C l and bismuth--5

a t . % l i t h i u m from t h e s t r i p p e r , f r e s h

a t . % l i t h i u m were added t o t h e system.

The f i n a l

two experiments (Nd-3 and Nd-4) w e r e conducted during January 1976. The system was n o t cooled t o room temperature u n t i l t h e f i r s t week of A p r i l 1976; t h u s t h e system w a s maintained a t t h e o p e r a t i n g temperature of

923 K f o r about l l m o n t h s .

The t h r e e a g i t a t o r s i n t h e c o n t a c t o r

and s t r i p p e r v e s s e l s were operated f o r about 700 h r a t speeds ranging

-43-

Table 7.

Measurements of emf between t h e bismuth s o l u t i o n s i n t h e c o n t a c t o r and s t r i p p e r v e s s e l s during runs Nd-1 and Nd-2 i n metal t r a n s f e r experiment MTE-3B

Calculated l i t h i u m concentration Li-Bi i n s t r i p p e r b (atom f r a c t i o n ) Run Nd-1

0 6.8 18 49 71 108

0.052 0.020 0.015 0.015 0.014 0.014

300 225 200 200 195 195 RUG Nd-2

0 11.5 30.8 48.1 63.6 78.1 100.1

165 165 155 124 100 88 25

0.0095 0.0095 0.0084 0.0057 0.0042 0.0036 0.0016

aRun t i m e = t i m e f r o m start of f l u o r i d e s a l t c i r c u l a t i o n .

bBased on t h e assumption t h a t t h e i n i t i a l c o n c e n t r a t i o n of l i t h i u m (0.0012 at. %) i n t h e bismuth-thorium phase i n t h e c o n t a c t o r remained c o n s t a n t throughout runs Nd-1 and Nd-2. The i n i t i a l c o n c e n t r a t i o n of l i t h i u m i n t h e bismuth-lithium a l l o y i n t h e s t r i p p e r was Q 0.050 at. X .

-44between 100 and 300 rpm (1.67 t o 5.0 r p s ) during t h i s period. f l u o r i d e s a l t pump w a s i n o p e r a t i o n f o r maintained f o r

475 hr.

The

295 hr,and L i C l c i r c u l a t i o n w a s

With t h e exception of one of t h e a g i t a t o r seals

which developed a l e a k and allowed inleakage of argon b u f f e r gas i n t o t h e system s h o r t l y a f t e r t e r m i n a t i o n o f t h e last run (Nd-4),

a l l equipment

functioned without i n c i d e n t throughout t h e l i f e of t h e experiment. S p e c i f i c a l l y , no h e a t e r , thermocouple 3

o r c o n t r o l system malfunctions

occurred.

Also, no leakage of s a l t o r bismuth from t h e system w a s

observed.

The o u t s i d e s u r f a c e s of t h e carbon s t e e l process vessels were

inspected a f t e r shutdown t o determine t h e e f f e c t i v e n e s s of t h e oxidationr e s i s t a n t spray coating (METCO No. P443-10) i n p r o t e c t i n g t h e s e s u r f a c e s a g a i n s t o x i d a t i o n a t t h e o p e r a t i n g temperature.

The o u t s i d e s u r f a c e s

were found t o be i n e x c e l l e n t c o n d i t i o n , w i t h only a small amount of oxide present. During the f o u r runs conducted i n m e t a l t r a n s f e r experiment MTE-3B, 807 samples of t h e salt and bismuth s o l u t i o n s were taken f o r analyses.

As discussed above, t h e sampling procedures adequately obtained r e p r e s e n t a t i v e samples of t h e process s o l u t i o n s . 6.

DISCUSSION OF RESULTS

The o b j e c t i v e s of metal t r a n s f e r process experiments MTE-3 and WE-3B were t o measure t h e rate of removal of r e p r e s e n t a t i v e r a r e - e a r t h f i s s i o n products from a molten-salt breeder r e a c t o r f u e l s a l t and t o e v a l u a t e t h e s u i t a b i l i t y of mechanically a g i t a t e d c o n t a c t o r s f o r t h e

metal t r a n s f e r process.

Thus

it w a s necessary t o determine t h e o v e r a l l

mass-transfer c o e f f i c i e n t s f o r rare e a r t h s a t t h e t h r e e salt-bismuth i n t e r f a c e s i n t h e system and t o study t h e e f f e c t of a g i t a t i o n on t h e t r a n s f e r c o e f f i c i e n t s i n s t i r r e d contactors. I n metal t r a n s f e r process experiments MTE-3 and MTE-3BY only t h e o v e r a l l mass-transfer c o e f f i c i e n t s were measured, as discussed i n Sect. 4. R e s u l t s of i n d i v i d u a l mass-transfer c o e f f i c i e n t s i n s t i r r e d c o n t a c t o r s i n 5, 18-20 In which t h e phases are n o t dispersed have been reported. t h e s e s t u d i e s , mass-transfer c o e f f i c i e n t s i n organic-water, mercury-water, and LIF-BeF2-ThF4

salt-bismuth systems were determined, and c o r r e l a t i o n s

were developed which relate t h e i n d i v i d u a l mass-transfer c o e f f i c i e n t s f o r

-45-

each phase t o t h e p r o p e r t i e s of t h e s o l u t i o n s and system parameters such

as t h e s i z e and speed of t h e stirrer.

The r e p o r t e d dependence of t h e

mass-transfer c o e f f i c i e n t on t h e a g i t a t o r speed v a r i e d widely. The o v e r a l l mass-transfer c o e f f i c i e n t s obtained f o r neodymium a t t h e t h r e e salt-bismuth i n t e r f a c e s i n t h e f i v e r u n s i n experiments

MTE-3 and MTE-3B a t a g i t a t o r ( s t i r r e r ) speeds ranging from 1.67 r p s t o 5.0 r p s are show inlog-log p l o t s i n Figs. 21-23.

D i r e c t c o r r e l a t i o n of t h e

e f f e c t of a g i t a t o r speed on mass-transfer c o e f f i c i e n t s cannot be made because o t h e r system parameters

- particularly

t h e equilibrium

d i s t r i b u t i o n c o e f f i c i e n t s f o r neodymium -were not t h e same f o r a l l runs. Also, s i n c e t h e o v e r a l l mass-transfer c o e f f i c i e n t s w e r e determined by simultaneous s o l u t i o n of seven d i f f e r e n t i a l equations t o determine mass balance, p r e c i s e v a l u e s f o r t h e t h r e e c o e f f i c i e n t s

c a l c u l a t e d f o r each

r u n are not p o s s i b l e . Although t h e r e i s a g r e a t d e a l of scatter i n t h e d a t a shown i n Figs. 21-23,

t h e o v e r a l l mass-transfer c o e f f i c i e n t s g e n e r a l l y i n c r e a s e with

i n c r e a s i n g a g i t a t o r speed as p r e d i c t e d .

D i r e c t comparison of s e l e c t e d

v a l u e s from t h o s e r u n s i n which only t h e a g i t a t o r speed w a s changed (e.g.,

runs 3 and 4) c l e a r l y shows an i n c r e a s e i n t h e o v e r a l l m a s s -

t r a n s f e r c o e f f i c i e n t s when t h e a g i t a t o r speed w a s elevated from 1.67 t o 4.17 r p s .

S i m i l a r l y , a comparison of runs 6 and 7 (conducted i n a

previous experiment MTE-3) shows an i n c r e a s e when t h e a g i t a t o r speed w a s e l e v a t e d from 3.33 t o 5.0 r p s .

A dashed l i n e of s l o p e 1 i s included on

t h e s e f i g u r e s f o r r e f e r e n c e purposes only.

Various c o r r e l a t i o n s developed

i n t h e c i t e d r e f e r e n c e s i n d i c a t e t h a t mass-transfer c o e f f i c i e n t s â&#x20AC;&#x2DC;are p r o p o r t i o n a l t o a g i t a t o r speed r a i s e d t o a power between 0 . 9 and 1.65. The o v e r a l l mass-transfer c o e f f i c i e n t s f o r rare e a r t h s a c r o s s t h e

s a l t and bismuth phases determined i n experiments MTE-3 and MTE-3B were only about 1 t o 50% of those t h a t would b e p r e d i c t e d by c u r r e n t l y a v a i l a b l e c o r r e l a t i o n s , w i t h t h e l a r g e s t discrepancy occurring a t t h e l i t h i u m chloride--bismuth

interfaces.

F u r t h e r s t u d i e s are r e q u i r e d i n

o r d e r t o o b t a i n c o r r e l a t i o n s t h a t would r e l i a b l y p r e d i c t â&#x201A;Źhe o v e r a l l masst r a n s f e r c o e f f i c i e n t s f o r s t i r r e d c o n t a c t o r s i f t h i s type of c o n t a c t o r i s t o be used i n a f u l l - s c a l e processing p l a n t t o remove t h e r a r e - e a r t h

f i s s i o n products.

I n a d d i t i o n t o t h e i n f l u e n c e of a g i t a t o r speed and

p h y s i c a l p r o p e r t i e s of t h e s e v e r a l s o l u t i o n s ,

t h e e f f e c t of scale-up

t o l a r g e r processing equipment r e q u i r e s f u r t h e r i n v e s t i g a t i o n .

-46-

O R N L D W G 76-883

100 I

150

200

250

300

/â&#x20AC;&#x2122; / 0

I â&#x20AC;&#x2122;

J J

Fig. 21.

overall mass-transfer coefficients for neodymium at the fluoride salt-bismuth interface at agitator speeds of 100-300 rpm. Numbers in parentheses refer to run numbers. The datrhed line of slope = 1 shown for reference purposes only.

-4 7-

ORNL D W G 1 6 - 8 7 9

A G I T A T O R SPEED ( r p m )

100 I

150

200

250

300

(1) E

(31 E

(4)

LL v)

z a (L

I-

:IOâ&#x20AC;&#x2122;? 2

-t J

a a W >

to-; Fig. 22.

2 .o

2.1

2.2

2.3

2.4

2.5

L O G A G I T A T O R SPEED ( r P m )

Overall mass-transfer c o e f f i c i e n t s for neodymium at the lithium chloride-bismuth interface i n the contactor a t agitator speeds of 100-300 rpm. Numbers i n parentheses r e f e r t o run numbers. The dashed l i n e o f slope = 1 i s shown for reference purposes only. *

-48-

ORNL DWG 76-81?

C\GITATOR SPEED ( r p m l

lo-’

100

150

200

250 I

300 I

10-

I-

-0 W

I ’

/’ /’

LL LL

w 0 V

I ’ I ’

U W IL

(3)

a a

v) v)

I -J

lo-,

-J

a W

10-

1.9

2.0

2.1

2.2

2.3

2.4

2.5

L O G A G I T A T O R SPEED ( r p m )

Fig. 23.

Overall mass-transfer c o e f f i c i e n t s for neodymium at the lithium chloride/bismuth--5 a t . % lithium i n the stripper a t agitator speeds of 100-300 rpm. Numbers i n parentheses r e f e r to run numbers. The dashed l i n e of slope = 1 i s shown for reference purposes only.

-4 9An important f e a t u r e of t h e metal t r a n s f e r process i s t h e selective s e p a r a t i o n of thorium from t h e rare e a r t h s a t t h e bismuth--lithium

Rare earth-thorium s e p a r a t i o n f a c t o r s , defined as

chloride interface. ’RE-Th

(17)

DTh’DRE’

have been determined t o be i n t h e range of d i v a l e n t rare

earth^.^

lo4

lo8

f o r t h e t r i v a l e n t and

Thus n e g l i g i b l e l o s s of thorium from t h e f u e l

s a l t occurs i n t h e process.

Because of entrainment of t h e f l u o r i d e s a l t

i n t o t h e L I C l i n experiment MTE-3B, i t w a s not p o s s i b l e t o determine t h e separation f a c t o r .

However, during s t u d i e s i n t h e f i r s t experiment

MTE-3, i n which t h e rare e a r t h s europium, lanthanum, and neodymium were used, t h e s e p a r a t i o n f a c t o r s were estimated based on t h e t o t a l amount of ‘L

thorium (< 10 w t ppm) found i n t h e bismuth--5 stripper DTh/DRE

at. % lithium alloy i n the

a f t e r about 400 h r of operation.

Separation f a c t o r s f o r t h e s e rare e a r t h s i n t h e o r d e r of 1 04 t o 1 06 w e r e i n d i c a t e d .

Preliminary c a l c u l a t i o n s , using a computer code developed by W. L. Carter21 a t ORNL, have been made t o e s t i m a t e t h e contactor s i z e and o p e r a t i n g c o n d i t i o n s t h a t would be required i n o r d e r t o remove t h e r a r e - e a r t h f i s s i o n products a t t h e design rate22 from t h e r e f e r e n c e MSBR. For t h e s e c a l c u l a t i o n s , t h e rare e a r t h neodymium w a s chosen as a r e p r e s e n t a t i v e example, moles

(‘L

The d e s i g n removal rate of neodymium i s

174 g) per day f o r a breeding r a t i o of 1.06.

‘L

1 . 2 g-

(Note: Reducing

t h e r a r e - e a r t h removal rate would n o t have a p r o h i b i t i v e ‘ d e l e t e r i o u s e f f e c t on t h e breeding r a t i o

-a

r a t i o by about 0.01.)23

t h r e e f o l d reduction would lower t h e breeding I n t h e s e c a l c u l a t i o n s , t h e e f f e c t s of s e v e r a l

parameters (mass-transfer c o e f f i c i e n t s , i n t e r f a c i a l area, s a l t and bismuth flow rates, and number of e x t r a c t i o n s t a g e s ) on t h e removal r a t e of neodymium were evaluated, and a combination of parameters t h a t would be required t o meet t h e d e s i g n removal rate w a s determined. R e s u l t s of t h e s e c a l c u l a t i o n s are summarized i n Table 8 .

The

cases shown were s e l e c t e d t o i n d i c a t e t h e e f f e c t of several v a r i a t i o n s on neodymium removal rates. The f u e l - s a l t flow rate of 0.9 gpm (5.7 x loh5 m3 /see) w a s held c o n s t a n t f o r a l l cases s i n c e i t is t h e design f u e l - s a l t flow rate f o r t h e r e f e r e n c e processing p l a n t .

Three c o n t a c t o r s t a g e s

were used f o r a l l b u t one case s i n c e t h i s seemed t o be a reasonable compromise

based on preliminary c a l c u l a t i o n s .

For c a s e 1, t h e v a l u e s of o v e r a l l m a s s -

’r

-5 0t r a n s f e r c o e f f i c i e n t s a t t h e t h r e e salt-bismuth i n t e r f a c e s (K1,

K2, K3)

are r e p r e s e n t a t i v e of those obtained i n our experimental s t u d i e s .

The

area of 1 f t 2 (0.093 m2) p e r s t a g e , t h e bismuth flow rate of 3 gpm

(1.9 x lom4m3/sec), and t h e L i C l flow rate of 30 gpm (1.9 x m3/see) were chosen as a b a s i s f o r f u r t h e r e x t r a p o l a t i o n . As seen i n Case 1, t h e neodymium removal rate of 0.003 g-mole/day is about a f a c t o r of 400 below t h e d e s i g n v a l u e of 1 . 2 g-moles/day.

Increasing

o v e r a l l mass-transfer c o e f f i c i e n t s a t t h e LiC1-bismuth i n t e r f a c e s i n t h e c o n t a c t o r and s t r i p p e r by a f a c t o r of 5 (case 2) increased t h e removal rate by about a f a c t o r of 4.

The e f f e c t of i n c r e a s i n g t h e

i n t e r f a c i a l c o n t a c t areas t o 1 0 and 20 f t 2 (0.94 and 1.9 m2) is seen i n cases 3 and 4, and t h e e f f e c t of i n c r e a s i n g t h e number of s t a g e s

from 3 t o 6 is seen by comparing 4 and 5.

The r e s u l t s from i n c r e a s i n g

t h e bismuth and L i C l flow rates t o 6 gpm (3.8 x 60 gpm (3.8 x

m3/sec)

m3/sec) and

is seen i n cases 7 and 9.

In case 8 ,

t h e o v e r a l l mass-transfer c o e f f i c i e n t , K, a t t h e f l u o r i d e salt--bismuth i n t e r f a c e is increased by a f a c t o r of 10. F i n a l l y , t h e d e s i r e d removal r a t e i s reached by u s e of t h e parameters shown i n c a s e 11. For t h e choices made, a neodymium removal rate â&#x20AC;&#x2DC;of 1.37 g-moles/day i s i n d i c a t e d f o r t h e following system: 2 s a l t and bismuth i n t e r f a c i a l a r e a s / s t a g e = 20 f t 2 (1.86 m ), f l u o r i d e s a l t flow rate = 0.9 gpm (5.7 x bismuth flow rate = 18 gpm (1.1 x L i C l flow rate = 60 gpm (3.8 x

m2/sec),

K1 = 0.16 mm/sec, Kg = 1.0 mm/sec, and K3 = 4.0 mm/sec.

The v a l u e s f o r K1 and K2 a t t h e f l u o r i d e f u e l salt--bismuth

and LiC1--

bismuth i n t e r f a c e s i n t h e c o n t a c t o r (case 11) are about a f a c t o r of 1 0 higher than t h o s e observed i n m e t a l t r a n s f e r experiments.

Results

from s t u d i e s i n t h e water-mercury c o n t a c t o r s i n d i c a t e t h a t an i n c r e a s e of about a f a c t o r of 10 i n t h e mass-transfer c o e f f i c i e n t might be expected w i t h increased a g i t a t o r t u r b i n e diameter over t h o s e used i n t h e

metal t r a n s f e r experiments (1.4 m v s 0.073 m).24 t h e i n t e r f a c e between t h e LiC1--bismuth

The v a l u e f o r K3 a t

and t h e 5 at. % l i t h i u m i n t h e

s t r i p p e r (case 11) is about a f a c t o r of 100 higher than t h a t observed i n

metal t r a n s f e r experiments.

This l a r g e i n c r e a s e would l i k e l y r e q u i r e

-51increased a g i t a t i o n t o t h e p o i n t of some degree of d i s p e r s i o n of t h e s a l t and bismuth i n t h e s t r i p p e r ; however, t h i s would probably be a c c e p t a b l e s i n c e t h e l i k e l i h o o d of bismuth entrainment back i n t o t h e f u e l s a l t is minimal i n t h e s t r i p p e r vessel. Other combinations of t h e v a r i o u s parameters could be used t o achieve t h e required removal rate of neodymium.

Calculated r e s u l t s , shown i n

Table 8, are intended t o i n d i c a t e t h e e f f e c t of s e v e r a l parameters on t h e removal rate i n a f u l l - s i z e d m u l t i s t a g e metal t r a n s f e r process f o r t h e removal of r a r e - e a r t h f i s s i o n products (using neodymium as a n example) from a 1000-MW(e) MSBR.

CONCLUSIONS

The o b j e c t i v e s of t h e m e t a l t r a n s f e r process experiments were (1) t o study t h e v a r i o u s s t e p s i n t h e process, (2) t o measure t h e rate of removal of r a r e - e a r t h f i s s i o n products from t h e molten-salt r e a c t o r f u e l , and (3) t o e v a l u a t e t h e s u i t a b i l i t y of a mechanically a g i t a t e d c o n t a c t o r f o r u s e i n t h e process. Conclusions r e l a t i n g t o t h e s e o b j e c t i v e s are as follows: 1. During 15 experiments i n engineering-scale process equipment, r e p r e s e n t a t i v e r a r e - e a r t h f i s s i o n products (europium, lanthanum, and neodymium) were e x t r a c t e d from molten-salt breeder r e a c t o r f u e l s a l t (72-16-12 LiF-BeF2-ThF4)

mole X

and t r a n s f e r r e d i n t o bismuth-lithium a l l o y i n

t h e s t r i p p e r vessel. 2.

I n t h o s e e x p e r i m e n t s i n which entrainment of f l u o r i d e s a l t i n t o <

t h e L i C l s a l t d i d n o t occur, t h e rare e a r t h s w e r e s e l e c t i v e l y t r a n s f e r r e d (with r e s p e c t t o thorium) i n t o t h e bismuth-lithium 4 6 a l l o y . Separation f a c t o r s of about 1 0 t o 1 0 estimated i n t h e s e experiments compare favorably w i t h p r e d i c t e d v a l u e s of about 104 t o 1 08 f o r t r i v a l e n t and d i v a l e n t rare e a r t h s . Thus n e g l i g i b l e ' l o s s of thorium from t h e f u e l s a l t would occur i n t h e process.

Overall mass-transfer c o e f f i c i e n t s measured a t t h e t h r e e saltbismuth i n t e r f a c e s ( f u e l salt-bismuth, bismuth-LiC1, and LiC1-bismuth-lithium) i n t h e process were lower than would be required f o r f u l l - s c a l e metal t r a n s f e r process equipment of reasonable s i z e .

Table 8. Summary of c a l c u l a t i o n s on t h e e f f e c t of various parameters on neodymium removal rate i n t h e metal t r a n s f e r process using mechanically a g i t a t e d c o n t a c t o r s

Case number

Nd removed p e r day (g-moles)

S a l t and B i flow (m3/sec)

Fuel salt

Bismuth

LiCl

Mass t r a n s f e r coef. (mm/sec ) Y1 K2 K3

0.003

0.016

0.030

0.013

0.016

0.15

0.11

0.016

0.18

Area 2 (m / s t a g e )

Number of s t a g e s

0.040

0.093

0.20

0.093

0.15

0.20

0.93

0.016

0.15

0.20

1.86

0.24

0.016

0.15

0.20

1.86

0.37

0.016

0.75

1.0

1.86

0.55

0.016

0.75

1.0

1.86

0.67

0.16

0.75

1.0

0.61

0.016

0.75

1.0

1.86 1.86

1.05

0.16

1.0

40.0

1.86

1.37

0.16

1.0

40.0

1.86

-53-

4. The o v e r a l l mass-transfer c o e f f i c i e n t s i n c r e a s e d w i t h i n c r e a s i n g a g i t a t i o n ( a g i t a t o r speed) as expected, b u t meaningful c o r r e l a t i o n s w e r e n o t p o s s i b l e w i t h t h e l i m i t e d d a t a obtained.

I n t h e equipment used i n t h e s e experiments, t h e degree of a g i t a t i o n ( a g i t a t o r speed) was l i m i t e d by entrainment of f l u o r i d e s a l t i n t o t h e L i C l i n t h e contactor.

This

would r e q u i r e f u r t h e r e v a l u a t i o n and c a r e f u l design of mechanically a g i t a t e d c o n t a c t o r s f o r u s e i n t h e metal transfer

The e f f e c t of i n c r e a s e d equipment size (diameters of t h e process vessels and a g i t a t o r paddles) on t h e o v e r a l l mass-transfer c o e f f i c i e n t s and r a t e of removal f o r t h e rare e a r t h s w a s n o t s t u d i e d and need additional investigation. 8.

ACKNOWLEDGMENTS

The a u t h o r s g r a t e f u l l y acknowledge t h e a s s i s t a n c e of many Oak Ridge National Laboratory s t a f f members during t h e course of t h e two metal t r a n s f e r process experiments.

The design, i n s t a l l a t i o n , and o p e r a t i o n of

of t h e f i r s t experiment MTE-3, t o g e t h e r w i t h t h e a n a l y s i s of t h e r e s u l t s ,

were done by E. L. Youngblood, L. E. McNeese, W. L. Carter, and W. F. I

Schaffer, Jr.

The following members a s s i s t e d g r e a t l y w i t h t h e second

experiment MTE-3B:

J. Beams, C. H. Brown, Jr., R. M. Counce, R. B.

Lindauer, and R. 0 . Payne, experimental o p e r a t i o n ; W. R. Laing, H. A. Parker, and R. L, Walker, chemical a n a l y s e s ; and W. L. Carter and E. L. Youngblood, d a t a a n a l y s i s and i n t e r p r e t a t i o n . of Carol Proaps is g r e a t l y a p p r e c i a t e d .

The secretarial a s s i s t a n c e

-54-

REFERENCES

R. C. Robertson (ed.), Conceptual Design Study of a SingleFluid Molten-Salt Breeder Reactor, ORNL-4541 (June 1971).

L. E. McNeese, Engineering Development S t u d i e s f o r Molten-Salt Breeder Reactor Processing No. 5 , ORNL/TM-3140, pp. 2-15 (October 1971).

U. S. P a t e n t No. 3,853,979 (Dec. 1974).

L. E. McNeese, Engineering Development S t u d i e s f o r Molten-Salt Breeder Reactor-Processing No. 9, ORNLITM-3529, pp. 196-215 (December 1972).

C. H. Brown, Jr., e t al., Measurement of Mass-Transfer C o e f f i c i e n t s i n a Mechanically Agitated: Nondispersing Contactor Operating w i t h a Molten Mixture of LiF-BeF2-% and Molten Bismuth, ORNL-5143 (November 1976).

L. M. F e r r i s e t a l . , " D i s t r i b u t i o n of Lanthanide and Actinide Elements Between Molten Lithium Halide S a l t s and Liquid Bismuth Solutions," J. Inorg. Nucl. Chem. 34, 2921 (1972).

L. M. F e r r i s e t a l . , "Equilibrium D i s t r i b u t i o n of Actinide and Lanthanide Elements Between Molten Fluoride S a l t s and Liquid Bismuth S o l u t i o n s , J. Inorg. Nucl. Chem. 32, 2019 (1970). c

L. E. McNeese, Engineering Development S t u d i e s f o r Molten S a l t Breeder Reactor Processing No. 10, ORNL/TM-3352, pp. 57-59 (Dec. 1972).

E. L. Youngblood e t al., ORNL-4832, pp. 168-71.

10.

Chem. Tech. Div. Annu. Progr. Rep. Mar. 31, 1973, ORNL-4883, pp. 23-25.

i n MSBR Semiannu. Progr. Rept. Aug. 31, 1972,

11. L. M. F e r r i s e t al., " D i s t r i b u t i o n of Lanthanide and A c t i n i d e Elements Between Liquid Bismuth and Molten LiC1-LiF and LiBr-LiF Solutions," J. Inorg. Nucl. Chem. -934 313 (1972). 12.

G. J. Janz e t a l . , Molten S a l t s : Vol. 1, Electrical Conductivity, Density and V i s c o s i t y Data, NSRDS-NBS 1 5 (October 1968).

13.

MSRP Semiannu. Progr. Rep. Aug. 31, 1969, ORNL-4449, Tables 13.12, 13.13, p. 146 (February 1970).

14.

R. N. Lyon (ed.), Liquid Metals Handbook, NAVEXOS P-733, O f f i c e of Naval Research (June 1, 1950).

15.

L. E. McNeese, Engineering Development S t u d i e s f o r Molten-Salt Breeder Reactor Processing No. 10, ORNL/TM-3352, pp. 53-57 (December 1972).

-55-

16.

Chern. Tech. Div. Annu. Progr. Rep. Mar. 31, 1973, Om-4883,

17.

D. D. Sood and J. Braunstein, "Lithium-Bismuth Alloy Electrodes f o r Thermodynamics I n v e s t i g a t i o n of Molten LiF-BeF2 Mixtures," J. Electrochem. SOC. 121 (2) 247 (February 1974).

18.

J. B. Lewis, Chem. Eng. Sci. 3, 248 (1954).

19.

D. R. Olander, Chem. Eng. Sci. 18, 123 (1963).

20.

W. J. McManamey e t al., Chem. Eng. S c i .

21.

W. L. Carter, ORNL, personal communication.

22.

W. L. Carter and E. L. Nicholson, Design and Cost Study of a

p. 25.

28, 1061

(1963).

Fluorinator-Reductive Extraction-Metal Transfer Processing P l a n t f o r t h e MSBR, ORNL/TM-3579 (May 1972). 23.

L. E. McNeese and M. W. Rosenthal, "MSBR: A R e v i e w of Its S t a t u s and Future," Nucl. News (12), 52-58 (September 1974).

24.

J. R. Hightower, Jr., Engineering Development S t u d i e s f o r MoltenS a l t Breeder Reactor Processing No. 24, ORNL/TM-5339 ( i n p r e p a r a t i o n ) .

-56-

APPENDIX A:

SAMPLE ANALYSES FOR EXPERIMENT MTE-3B

The c o n c e n t r a t i o n s of 147Nd tracer and t o t a l neodymium i n each of t h e seven s a l t and bismuth phases i n metal t r a n s f e r experiment MTE-3B during r u n s Nd-1 through Nd-4 are t a b u l a t e d i n Tables A-1 through A-8. The 147Nd tracer c o n c e n t r a t i o n s were determined by counting t h e 0.53-MeV gamma emitted by t h e 147Nd tracer.

Values are c o r r e c t e d f o r decay during

t h e run (t = 11 d ) . R e s u l t s f o r t o t a l neodymium w e r e obtained by 112 chemical a n a l y s e s using a n i s o t o p i c d i l u t i o n m a s s spectrometry procedure. A l l samples were counted f o r 147Nd c o n t e n t s .

Analyses f o r t o t a l

neodymium were done on alimitednumber of r e p r e s e n t a t i v e samples (1) t o e s t a b l i s h t h a t t h e 147Nd-tracer d a t a represented t h e t o t a l neodymium c o n c e n t r a t i o n , (2) t o v e r i f y t h e adequacy of t h e sampling procedure, and (3) t o check on t h e accuracy of t h e inventory of t h e neodymium i n t h e system.

-57Table A-1.

Concentrations of 147Nd i n t h e s a l t and bismuth phasesa d u r i n g r u n Nd-l,b WE-3B

Run time (hr)d

FSV x

FSC6 x 10

IO6

0 1.6 4.8 6.8 9.6 12.6 15.6 18.1 22.6 25.6 29.1 33.1 37.1 41.1 45.1 49.1 55.8 61.6 71.6 79.6 85.8 96.8

1.37 f 1.31 1.18 1.20 1.15 1.23 1.21 1.18. 1.22 1.27 1.18 1.25 1.19 1.14 1.20 1.16 1.20 1.16 1.16 1.10 1.03 1.07

96.9 98.8 100.8 103.8 106.8 108.8 112.8 113.8

1.09 1.04 1.08 1.11 1.01 1.23 1.16

1.03 0.94 0.93 0.84 0.78 0.71 0.71

1.05 1.01 1.02

0.62 0.63 0.56

0.60 1.05 1.14 1.13 1.18 1.13 1.13 1.17 1.18 1.11 1.22 1.11 1.12 1.17 1.18 1.17 1.12 1.15 1.09 1.06 1.07

115.8 Ae Be Ce

147Nd c o n c e n t r a t i o n j d i s min-1 g -1)c BTF BTC csc . css 104 104 104 104

BLS 105

0 1.40 1.93 2.26 2.11 1.96 1.53 1.03 1.59 2.50 1.50 1.76 1.66 1.87 0.99 1.52 1.95 2.33 2.10 2.19 1.84 1.16

0 0.044 0.17 0.29 0.48 0.53 0.85 1.0 1.13 1.19 1.50 1.71 1.63 1.81 1.68 2.35 2.68 2.94 3.60 3.45 3.58 4.35

0 0.63 1.20 1.20 1.30 1.37 1.28 0.93 1.29 1.29 1.12 0.99 1.53 2.34 1.24 1.29 1.53 1.75 1.47 1.66 1.41 2.28

0 1.12 2.41 3.36 0.77 3.42 3,41 4.08 2.09 4.57 2.95 2.82 2.32 3.52 3.97 3.50

0 0.68 2.42 2.57 2.84 2.42 2.92 2.61 2.28 2.97 2.93 4.13 3.84 3.08 2.21 2.84

5.11 3.35 4.02 3.78 4.85 3.98

2.40 2.82 2.81 2.87 1.80

Stopped f l u o r i d e s a l t c i r c u l a t i o n 1.78 0.98 2.19 2.39 0.91 1.20 4.26 2.05 0.93 1.16 3.12 <6.79* 1.42 1.25 3.24 <5.27* 1.80 0.83 2.24 _i5.8* 0.91 1.08 <6.59* 518.4* <7.31* <14.8* 1.52 0.93 Stopped LiCl c i r c u l a t i o n 0.93 <12.9* <4.74* 1.04 <4.11* 52.11* 0.47 0.56 0.25* 8.98* 0.57 0.77

4.60 6.50 4.66 4.66 4.92 5.45 5.06

5.18 4.56

5.13

b A g i t a t o r speed = 5.0 r p s . k s i n t e g r a t i o n s p e r minute p e r gram of s o l u t i o n c o r r e c t e d f o r decay. dRun t i m e = t i m e e l a p s e d after start of f l u o r i d e s a l t c i r c u l a t i o n . e Equilibrium c o n d i t i o n s w i t h no s a l t c i r c u l a t i o n . -1 -1 'This v a l u e is read as 1.37 x lo6 d i s min g *These v a l u e s are q u e s t i o n a b l e due t o u s e of d i f f e r e n t procedure and counting equipment.

-58-

Table A-2:

Run time

0 9.6 18.1 22.6 25.6 29.1 33.1 41.1 49.1 55.8 79.6 96; 8 100.8 103.8 106.8 115.8 115.8 d

FSV

FSC

21.6

0 17.8 17.6

Neodymium c o n c e n t r a t i o n ( u g f g ) BTF BTC csc

0 0.15

0 0.14

0.36

0.06

0.57 0.25 0.35 0.27

css

0.03

0.11 0.91

18.3

17.6 17.2

BLS

17.9 16.5

Neodymium c o n c e n t r a t i o n s i n t h e s a l t and bismuth phasesa during run Nd-l,b MCE-3B

0.57

1.96

0.27 16.9 21.3

0.17 0.10

0.11

0.14 0.38

0.25

2.24 5.04

Stopped f l u o r i d e s a l t c i r c u l a t i o n 0.31

15.8 16.7

17.4

16.1

0.11 0.08

9.2

Stopped L i C l c i r c u l a t i o n 0.08 0.17 0.78

0.10

0.32

0.31 3.22

<o .0 1

3.36 -

FSV = f l u o r i d e salt. i n t h e r e s e r v o i r ; FSC = f l u o r i d e s a l t i n t h e c o n t a c t o r ; BTF = bismuth thorium i n t h e f l u o r i d e s a l t s i d e of the c o n t a c t o r ; BTC = bismuththorium i n t h e L i C l s i d e of t h e c o n t a c t o r ; CSC = L i C l i n t h e c o n t a c t o r ; CSS = L i C l i n t h e s t r i p p e r ; BLS = bismuth--5 a t . % l i t h i u m i n t h e s t r i p p e r .

bAgitator speed = 5.0 r p s . 5 u n time = time elapsed a f t e r start of f l u o r i d e s a l t c i r c u l a t i o n . dEquilibrium conditions w i t h no s a l t c i r c u l a t i o n .

-59Table A-3.

Run time (hr)d

Concentrations of 147Nd i n t,.e s a l t and bismuth phasesa during r u n Nd-2,b MTE-3B 147Nd c o n c e n t r a t i o n ( d i s min

lo6

0 2.2 7 .O 11.o 15.0 19 .o 23.0 27 .O 31.O 35.8 42.1 49 .O 57.0 63. 3e 70.8 78.8 87.3 94.5 102.5 110.8 121.3 130.3 138.3 139 .O 146.8 145.1 164 .O

171.0

1.61f 1.48 1.43 1.47 1.38 1.41 1.35 1.36 1.35 1.41 1.37 1.31 1.27 1.25 1.28 1.31 1.19 1.37 1.26 1.38 1.35 1.40 1.36 1.47 1.39 1.42 1.61

FSC+ x 10

0.058 1.02 1.26 1.44 1.35 1.35 1.38 1.30 1.26 1.27 1.34 1.22 1.22 1.19 1.25 1.43 1.52

1.34 1.39 1.22 1.36 1.44

BTP

csc

BTC

104

0.12 1.92 2.96 2.82 1.73 0.98 1.76 3.61 2.05 2.68 2.35 1.49 2.50 2.19 2.35 3.48 3.45 2.98 2.23 2.05 3.70 2.43 2.45

0.11 1.03 1.88 1.62 0.89 0.89 1.41 1.39 1.38 1.45 1.47 1.45 2.14 1.42 1.78 2.37 2.60 2.48 1.95 1.34 1.78 2.33 1.95

Stopped f l u o r i d e s a l t 1.42 2.13 1.51 2.04 1.16 1.42 2.29 1.53

css

104

KO. 56

<0.38 -

.c.

4.92 8.54 6.01 4.82 5.53 7.01 7.10 8.01 7.30 11.8 6.82 7.25 11.1 14.0 35.1 44.8 29.7 19.1 20.4 20.8 21.8 19.9

and LiCl 2.08 1.85 2.02 1.71

-1 g-l)c

1.41 1.68 3.29 2.68 4.40 5.16 4.27 4.86 3.12 4.09 3.81 5.22 9.42 14.1 44.6 50.3 28.2 20.3 22.4 21.7 22.6 19.8

salt circulation 22.1 22.4 21.9 55.6 21.0 20.7 17.4 23.5

BLS 105 0.56 0.53 0.89 1.16 1.49 1.80 2.21 2.57 2.78 3.29 3.87 5.02 4.90 6.42 5.98 5.39 1.65 0.57 0.43 0.46 0.42 0.46 0.39 0.39 0.44

0.40 0.46

a FSV = f l u o r i d e s a l t i n t h e r e s e r v o i r ; FSC = f l u o r i d e s a l t i n t h e c o n t a c t o r ; BTF = bismuth-thorium i n t h e f l u o r i d e s a l t s i d e of t h e c o n t a c t o r ; BTC = bismuth-thorium i n t h e LiCl s i d e of the c o n t a c t o r ; CSC = LiCl i n t h e c o n t a c t o r ; CSS = LiCl i n t h e s t r i p p e r ; BLS = bismuth--5 a t . % l i t h i u m i n t h e s t r i p p e r . b A g i t a t o r speed = 5.0 r p s . % i s i n t e g r a t i o n s p e r minute p e r gram of s o l u t i o n c o r r e c t e d f o r decay d u r i n g run.

t i m e from start of f l u o r i d e s a l t c i r c u l a t i o n . eI n c r e a s e i n 147Nd i n L i C l i n d i c a t e d loss of r e d u c t a n t i n s t r i p p e r .

dRun t i m e

f T h i s v a l u e is read as 1.61 x

lo6

d i s min

-1 -1 g

-60-

Table A-4.

Neodymium c o n c e n t r a t i o n s i n t h e s a l t and bismuth phasesa during run Nd-2,b MTE-3B

RUn

time. (hr)"

0 2.2 7.0 11.0 15 .O 19 .o 35 .O 42.1 57.0 78. Bd 102.5 130.3 138.3

FSV

FSC

Neodymium concentration (ug/g) BTF BTC csc

30.4

9.2

0.08

32.9

0.34 0.21

0.17

0.34

css <0.01 0.55

BLS

3.36

7.8 33.6 29.7 41.2 36 .O

139 .O 146.8 171.0 182 .O

29.1 26.3

0.03 0.25 0.45 0.32

0.10 0.06 0.06

11.9 1.33 0.92 0.88

0.42 0.32 0.71

7.6 15.1

32.8 8.0 5.3

0.59 0.83

Stopped f l u o r i d e s a l t and L i C l c i r c u l a t i o n 7.6 35.4 0.32 0.07 8.0

1.01

33.6 47.6 35.4

0.03 1.09 0.27

37 .O

= f l u o r i d e s a l t i n t h e r e s e r v o i r ; FSC = f l u o r i d e s a l t i n t h e c o n t a c t o r ; BTF = bismuth-thorium i n t h e f l u o r i d e s a l t s i d e o f t h e c o n t a c t o r ; BTC = bismuth-thorium i n t h e L i C l s i d e of t h e c o n t a c t o r ; CSC = L i C l i n t h e contact o r ; CSS = L i C l i n t h e s t r i p p e r ; BLS = bismuth--5 at. % l i t h i u m i n t h e s t r i p p e r .

%SV

bAgitator speed = 5.0 r p s . C

Run time dIncrease decrease stripper

= time elapsed a f t e r s t a r t of f l u o r i d e s a l t c i r c u l a t i o n . i n t h e neodymium concentration i n t h e L i C l i n t h e s t r i p p e r and of t h e neodymium concentration i n t h e Bi--5 a t . X l i t h i u m i n t h e i n d i c a t e d loss of l i t h i u m r e d u c t a n t i n t h e s t r i p p e r .

-61Table A-5.

Concentrations of 147Nd i n t h e s a l t and bismuth phasesa during run Nd-3,b MTE-3B 147Nd c o n c e n t r a t i o n ( d i s min -1 g-l)d

t iRun meC (hr)

0 1.5 4.3 11.5 18.8 19.8 27.0 35.7 43.8 51.0 59.5 68.0 74.8 83.5 92.0 99 .o 107.5 107.8 115.6 139.5 165.2

FSC

FSV

x 10

2.88

-----

3.02

---

x 10

BTC

csc

lo4

x 10

0 0 0 0 1.88 3.55 1.94 0.7 3.07 4.22 3.62 3.63 3.00 4.85 2.50 3.87 Stopped F l u o r i d e S a l t C i r c u l a t i o n 2.78 4.55 3.21 21.7 2.77 4.04 2.56 26.6 2.52 4.20 3.01 19.4 2.26 2.71 2.49 13.7 2.29 3.53 2.03 16.7 1.99 3.38 1.96 21.0 1.90 2.39 1.84 12.0 1.84 2.62 1.63 22.4 1.63 3.73 1.52 12.5 1.49 2.53 1.54 9.3 1.48 3.00 2.26 11.8 1.31 1.46 1.08 7.4 Stopped LiCl C i r c u l a t i o n 16.4 2.01 5.33 1.54 1.24 1.24 15.5 1.26 1.36 1.44 12.0

0 0.7 1.35 3.33

3.31

css

3.67e 3.05 3.27 2.99

lo6

BTF

BLS x lo5 0

0 0 0

9.84 40.1 19.3 22.4 24.4 23.6 13.5 24.1 8.3 8.7 7.1 9.8

0.052 0.16 0.66 0.80 1.23 1.62 1.92 2.11 2.62 2.65 2.86 3.26

2.1 co.9 <0.8

3.16 3.13 3.15

FSV = f l u o r i d e f u e l s a l t i n t h e r e s e r v o i r ; FSC = f l u o r i d e f u e l s a l t i n t h e bismuth-thorium i n t h e f l u o r i d e s a l t s i d e of t h e c o n t a c t o r ; BTY contactor; BTC = bismuth-thorium in the LiCl side of the contactor; CSC = L i C l i n t h e c o n t a c t o r ; CSS = LiCl i n the s t r i p p e r ; BLS = bismuth--5 a t . X lithium i n the stripper.

bAgitator speed i n t h e c o n t a c t o r and s t r i p p e r was 4.17 r p s . 'Run

time = time elapsed after t h e s t a r t of flue-ride salt c i r c u l a t i o n .

d D i s i n t e g r a t i o n s p e r minute p e r gram of s o l u t i o n c o r r e c t e d f o r decay.

ernis v a l u e

is read as 3.67 x 1 06 d i s min-1 g-1

-62Table A-6.

Neodymium c o n c e n t r a t i o n s i n t h e s a l t and bismuth phases,a d u r i n g r u n Nd-3,b MTE-3B

RUn

timeC (hr) 0 1.5 4.3

11.5 18.8 19.8 27.0 35.7 43.8 51.0 59.5 68.0 74.8 83.5 92.0 99.0 107.5 107.8 115.6 139.5 165. 2d

Neodymium concentration (pg/g) BTF BTC csc cs s

FSV

FSC

47.3

34.2

0.28

0.15

0.34

0.56

44.7

0.32

0.36

1.20

0.46

0.53

47.7

46.3

Stopped F l u o r i d e S a l t C i r c u l a t i o n 0.42 0.59 2.24

40.9

0.08

0.34

1.67

35.7 30.7

47.2

22.3 20.7

0.56 1.53 2.27

0.11

0.25

1.08

1.82

26.5 21.7

BLS

4.34 5.05

0.20 0.14 0.71 Stopped L i C l C i r c u l a t i o n 0.85 0.18 0.85 0.17 0.10

0.50

5.17

0.03 0.03

7.28

aFSV = f l u o r i d e s a l t i n t h e reservoir; FSC = f l u o r i d e s a l t i n t h e c o n t a c t o r ; BTF = bismuth-thorium i n t h e f l u o r i d e s a l t s i d e of t h e c o n t a c t o r ; BTC = bismuth-thorium i n t h e L i C l s i d d of t h e c o n t a c t o r ; CSC = L i C l i n t h e c o n t a c t o r ; CSS = LiCl i n t h e s t r i p p e r ; BLC = bismuth--5 a t . % lithium i n the stripper. bAgitator speed = 4.17 r p s . â&#x20AC;&#x2DC;Run time = time elapsed after s t a r t of f l u o r i d e s a l t c i r c u l a t i o n . dEquilibrium c o n d i t i o n s w i t h no s a l t c i r c u l a t i o n .

-63-

Table A-7.

Run timeC (hr)

0 4.2 14.0 21.0 21.3 28.3 36.8 45.3 52.3 60.8 69 .O 76.3 84.8 93.2 100.5 109.4 109.5 117.0 135.8 165.9

Concentrations of 147Nd i n t h e s a l t and bismuth phasesa d u r i n g r u n Nd-4,b MTE-3B

FSV

FSC

x 10

3. 31e 2.80 2.73 2.76

1.26 2.75 2.67 2.72

---

2.77 1.88 2.39 2.38 2.23 2.28 2.47 2.36 1.88 2.21 2.12

----

2.34 2.37 2.35

---2.59

-----

147Nd concentration ( d i s min-1 -1)d BTF BTC csc css

x 10

1.36 1.44 12.0 4.63 2.20 8.32 3.32 2.45 6.16 4.49 3.22 10.5 Stopped F l u o r i d e S a l t C i r c u l a t i o n 3.98 2.67 8.93 3.30 2.16 5.96 2.84 2.30 6.35 5.42 2.49 8.83 3.37 2.49 7.22 2.19 7.11 3.76 5.69 2.47 7.86 3.01 2.51 11.0 7.37 2.31 8.04 2.59 2.25 5.72 2.61 5.15 3.03 Stopped L i C l c i r c u l a t i o n 3.62 2.59 11.4 3.30 2.41' 20.8 4.55 2.25 29.2

x 10

BLS x 1 05

<O .08 7.92 6.74 7.92

3.15 3.36 3.24 3.34

1.58 4.74 7.72 11.4 5.50 8.69 6.17 11.3 9.80 21.7 10.3

3.35 3.43 3.57 3.62 3.59 3.68 3.78 3.91 3.87 4.12 3.89

-3.3

4.15 4.06 4.27

22.3 -

42.2 -

a FSV = f l u o r i d e f u e l s a l t i n t h e r e s e r v o i r ; FSC = f l u o r i d e f u e l s a l t i n t h e c o n t a c t o r ; BTF = bismuth-thorium i n t h e f l u o r i d e s a l t s i d e of t h e c o n t a c t o r ; BTC = bismuth-thorium i n t h e LiCl s i d e of t h e c o n t a c t o r ; CSC = L i C l i n t h e c o n t a c t o r ; CSS = L i C l i n t h e s t r i p p e r ; BLS = bismuth--S a t . % lithium i n the stripper. bAgitator speed i n t h e c o n t a c t o r and s t r i p p e r was 1.67 r p s . C

Run t i m e = time elapsed a f t e r t h e s t a r t of f l u o r i d e s a l t c i r c u l a t i o n .

d D i s i n t e g r a t i o n s p e r minute p e r gram c o r r e c t e d f o r decay.

6 -1 -1 g eThis v a l u e i s r e a d 'as 3.31 x 1 0 d i s min

-64Table A-8. Run timeC (hr)

0 4.2 14.0 21.0 21.3 36.8 45.3 52.3 60.8 69 .O 76.3 84.8 93.2 100.5 109.4 109 .Sd 135. 8d 165.9 262. Od

Neodymium c o n c e n t r a t i o n s i n t h e s a l t and bismuth phasesa d u r i n g r u n Nd-4,b MTE-3B

FSV

FSC

47.2

20.7

Neodymium concentration (vg/g) BTF BTC csc 0.17

43.7

0.10

0.85

47.3

css

BLS

0.03

7.28

0.36

0.36 Stopped Fluoride S a l t C i r c u l a t i o n 0.42 0.39 41.6 0.35 0.38 40.2 0.35 0.46 0.29 37.2 37.8 0.34 0.36 0.25 36.1 0.35 Stopped L i C l C i r c u l a t i o n 34.7 0.29 1.05 36.0 0.34 0.85 36.1 0.29 0.25 1.34

7.73 0.48 4.27 0.45

9.13

0.63 7.46 1.96

6.58 6.50

0.11 0.03 0.03

8.54 8.40 9.24

a FSV = f l u o r i d e s a l t i n t h e r e s e r v o i r ; FSC = f l u o r i d e s a l t i n t h e c o n t a c t o r ; BTF = bismuth-thorium i n t h e f l u o r i d e s a l t s i d e of t h e c o n t a c t o r ; BTC = bismuth-thorium i n t h e LiCl s i d e of t h e c o n t a c t o r ; CSC = L i C l i n t h e c o n t a c t o r ; CSS = LiCl i n t h e s t r i p p e r ; and BLS = bismuth--5 a t . X lithium i n the stripper. bAgitator speed = 1.67 r p s . C

Run t i m e = t i m e elapsed a f t e r start o f f l u o r i d e s a l t c i r c u l a t i o n .

dEquilibrium c o n d i t i o n s w i t h no s a l t c i r c u l a t i o n .

-65-

OW-517 6 D i s t . Category UC-76 Internal Distribution L i s t 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17-20. 21. 22.

R. C. W. W. R.

F. J. F. J.

E. H. D. L. M.

L. M. L. R. L. R. E. M. R. W.

R. J. D. L. W. R. R. F. J. R.

c. w.

A. D.

Brooksbank 3rown, Jr. Burch Carter Counce Culler Dale Daley DiSt e f ano E g l i , ERDA-OR0 Engel Ferguson Ferris Grimes Glass Hibbs Hightower, Jr Kee Kelmers

23. 24. 25. 26. 27. 28. 29. 30-32. 33. 34. 35. 36-39. 40. 41. 42. 43. 44. 45-46. 47. 48-50. 51.

W. R. Laing J. A. Lenhard, ERDA-OR0

E. Leuze E. MacPherson P. M a l inauskas L. Matthews, ERDA-OR0 H. E. McCoy L. E. McNeese E. Newman H. Postma M. W. Rosenthal H. C. Savage C. D. S c o t t W. F. S c h a f f e r , Jr. D. B. Trauger R. G. Wymer E. L. Youngblood C e n t r a l Research Library Document Reference S e c t i o n Laboratory Records Laboratory Records (LRD-RC) R. R. A. C.

Consultants and Subcontractors 52. 53. 54. 55. 56.

W. K. Davis E. C. R. D.

L. Gaden, Jr. H. Ice B. Richards O'Boyle

External Distribution 57. 58.

59-60. 61-172.

Research and Technical Support Division, Energy Research and Development Administration, Oak Ridge Operations O f f i c e , P. 0. Box E, Oak Ridge, TN 37830 D i r e c t o r , Reactor Division, Energy Research and Development Administration, Oak Ridge Operations O f f i c e , P. 0. Box E, Oak Ridge, TN 37830 D i r e c t o r , Division of Nuclear Research and Applications, Energy Research and Development Administration, Washington, D. C. 20545 For d i s t r i b u t i o n as shown i n TID-4500 under UC-76, Molten-Salt Reactor Technology

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