' DPST-85-926

The Effects of Gamma Irradiation on the Rheology of KTPB Slurries

by D. D. Walker E. 1. du Pont de Nemours and Company Savannah River Site Aiken, South Caro1,ina 29808 ,

J. P. Doherlv

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Precipitat ion process, Rheology, Irradiation effects

TECHNICAL DIVISION SAVANNAH RIVER LABORATORY

MEMORANDUM '

TO: M . A. EBRA, 773-A

'SUMMARY

DPST-85-926 . &@C. A&?* /w777

CC: G: W. W i l d s , 773-A M. D. B o e r s m a (31 , 676-T C. T. Randal l , 704-T R. E. Ei .bl ing, 773-A J. C. Marek, 676-1T M. C. H.- Fong, 676-1T D. T. Hobbs, 773-A MSM F i l e , 773-A SRL F i l e ( 4 1 , 773-A

November 5, 1985

SRL RECORD COPY

THE EFFECTS OF GAMMA IRRADIATION ON THE RHEOLOGY .OF KFPB SLURRIES

I r r a d i a t i o n of t h e p r e c i p i t a t e from t h e in-tank decontaminat ion p rocess c a u s e s dramatic decreases i n t h e y i e l d stress and cons i s t ency of t h e s l u r r y . Experiments u s ing s imula t ed s l u r r i e s

, have produced t h e fo l lowing r e s u l t s :

o The yield stress of a 1 0 weight % s l u r r y . d e c r e a s e s f r o m 200-300 dynes/cm2 t o less t h a n 1 0 dynes/an2 a f t e r a n i r r a d i a t i o n dose of 4.8 x l o 7 rads ( e q u i v a l e n t t o approximate ly 4 months of t a n k farm storage).

The cons i s t ency decreases from 30-50 c p t o less than 1 0 cp a f t e r t h e same i r r a d i a t i o n dose.

o

o For a mixture of slurries which have received d i f f e r e n t r a d i a t i o n doses, t h e y i e l d stress i s approximately equa l t o t h e ave rage of t h e y i e l d stresses of t h e component s l u r r i e s . The c o n s i s t e n c y of a mix tu re t e n d s t o be close t o t h e c o n s i s t e n c y of t h e most v i scous component.

.

Based on these r e s u l t s , t h e pump requi rements for t r a n s f e r r i n g t h i s

M. A. EBRA -2- DPST-85 - 9 2 6 November 5 , 1985

s l u r r y f r o m the s t o r a g e t a n k t o t h e S a l t Process ing C e l l (SPC) i n t h e , Defense Waste Process ing F a c i l i t y (DWPF 1 can be s i g n i f i c a n t l y reduced. t o t r a n s f e r a s l u r r y w i t h a y i e l d stress of 300 dynes/cm2 and a c o n s i s t e n c y of 50 cp. These requi rements can be reduced t o 1 0 0 dynes/an2 and 30 cp.

INTRODUCTION

The p r e s e n t s p e c i f - i c a t i o n s r e q u i r e t h a t t h i s pump be a b l e

During t h e in- tank decontaminat ion process , - cesium, potassium and , ammonium i o n s are p r e c i p i t a t e d as t h e i r i n s o l u b l e t e t r a p h e n y l b o r a t e salts . .Cross- f low f i l t r a t i o n separates t h e l i q u i d from t h e so l id s and c o n c e n t r a t e s t h e , p r e c i p i t a t e t o a 1 0 w t % so l id s s l u r r y . A f t e r washing t o remove s o l u b l e salts , t h e precipitate is stored i n a 1.3 m i l l i o n g a l l o n Type I11 waste tank. The s l u r r y w i l l e v e n t u a l l y be t r a n s f e r r e d t o t h e S a l t P rocess ing C e l l (SPC) of t h e Defense Waste Process ing F a c i l i t y (DWPF) fo r ' i n c o r p o r a t i o n of t h e r a d i o a c t i v i t y i n t o borosilicate glass.'

I n i t i a l l y , t h e p r e c i p i t a t e acts l i k e a Bingham p l a s t i c f l u i d w i t h a h i g h y ie ld stress and cons i s t ency . s l u r r y from t h e storage t a n k t o t h e DWPF r e q u i r e s a s p e c i a l l y des igned pulpp. However, d u r i n g t h e p r e c i p i t a t i o n , f i l t r a t i o n , washing, and c o n c e n t r a t i o n steps of t h e in- tank process, t h e p r e c i p i t a t e receives an i r r a d i a t i o n dose from t h e p r e c i p i t a t e d Cs-137 and t h e adsorbed Sr-90, r e a d y ~ t o be t r a n s f e r r e d from t h e p rocess ing tank t o t h e storage t a n k , it has received a s i g n i f i c a n t r a d i a t i o n dose d u r i n g t h e 1 0 0 days r e q u i r e d for p rocess ing , cont inues to be irradiated as b a t c h e s are added from in- tank p r o c e s s i n g and removed ' to t h e DWPF. of precipitate i n t h e storage t a n k (1.05 x 106 g a l l o n s ) ; t h e average l i f e t i m e i n t h e t a n k is t w o years. material b a l a n c e for t h e process ( R e f , - 2 1 , t h e expected r a d i a t i o n dose i s

T h e r h e o l o g i c a l p r o p e r t i e s of s imula t ed KTPB S l u r r i e s ( R e f . 1) and t h e p r e c i p i t a t e from , t h e f u l l . scale in- tank demonst ra t ion ( R e f . 3 ) have been measured. For s i m u l a t e d . s l u r r i e s , t h e y i e l d stress i s . d i r e c t l y p r o p o r t i o n a l t o t h e c o n c e n t r a t i o n of i n s o l u b l e s o l i d s (IS) o v e r t h e r a n g e of ' c o n c e n t r q t i o n s ' s t u d i e d ( 4 t o 20 w t % I S f o r unwashed s l u r r y , 9 t o 1 3 w t % I S for washed s l u r r i e s - ) . Yield stresses ranged from 32 dynes/cm2 f o r a 4.1 w t % I S sample t o 646,. ' . dynes/cm2 for a 19.5 w t % I S sample. found t o be a l i n e a r f u n c t i o n of t h e i n s o l u b l e so l id s c o n c e n t r a t i o n (10 c p f o r 4.1 w t ' % - I S , 110 cp f o r 19.5 w t % I S ) . Ne i the r p rope r ty w a s a f f e c t e d . s i g n i f i c a n t l y by t h e s o l u b l e salts i n unwashed samples, o r by sodium ti tanate.

To t r a n s f e r t h i s v e r y t h i c k

Thus, a t t h e time t h e precipitate i s

During storage, t h e precipitate

Because of t h e ' large inven to ry

B a s e d on t h e m o s t r e c e n t

1 - 4 5 x l o 8 r ads /y r (See Appendix A) .

The cons is tency w a s also

. .

DP ST-8 5 - 9 2 6 M. A. EBRA -3- November 5 , 1985

The r h e o l o g i c a l p r o p e r t i e s o f a s l u r r y sample from t h e f u l l s c a l e in- tank demonst ra t ion were measured d e s p i t e extrcpe d i f f i c u l t i e s i n o b t a i n i n g and handl ing t h e material (Ref 3 ) However, t h e observed y i e l d stress and cons i s t ency of t h e r a d i o a c t i v e s l u r r y were s i g n i f i c a n t l y lower t h a n p r e d i c t e d from t h e work on non-radioact ive systems (Tab le 1). of r a d i o a c t i v e s l u r r y was concen t r a t ed t o 1 2 w t % s o l i d s . measured yield stress was 72 dynes/cm2 compared to t h e expected 340 dynes/cm2 (based on non-radioact ive s imulan t s ) . Because of t h e low Cs-137-ac t iv i ty i n t h e s a l t s o l u t i o n used for t h e demonst ra t ion , t h e r a d i a t i o n dose rece ived by t h e s l u r r y during t h e 7 months of process ing and s t o r a g e on ly corresponded t o a 5 week dose under t h e a n t i c i p a t e d ave rage o p e r a t i n g cond i t ions . t h e r e s u l t s d i scussed below, t h i s low y i e l d stress can be accounted f o r by t h e radiat ion dose t h e s l u r r y rece ived .

Seven months a f t e r t h e demonstrat ion, a sample The -

Based on

The E f f e c t of Radia t ion .on Rheological Properties

To de te rmine t h e e f f e c t of i r r a d i a t i o n , s imulated 1 0 ' w t % potassium t e t r a p h e n y l b o r a t e (KTPB) s l u r r i e s w e r e i r r a d i a t e d i n a Co-60 gamma s o u r c e f o r t h e equ iva len t ' of up t o 2 yea r s of tank farm s to rage . Rad ia t ion doses of l o 7 rads s i g n i f i c a n t l y lowered t h e y i e ld stress' and cons i s t ency of t h e s l u r r i e s , The r e s u l t s of t h e s e tests are l i s t e d i n Table I1 and i n F igu res 1 and 2. The range of radiation doses used were comparable t o a 1 month t o 2 yez r storage per iod i n t h e tank farm, Appendix A. A s can be seen i n Table 11, a f t e r a dose equ iva len t t o 6 mohths under tank farm storage cond i t ions t h e s l u r r y e x h i b i t s no y i e l d stress and behaves s i m i l a r t o water. Most of t h e . d e c r e a s e occur s du r ing t h e f i r s t 3 x l o 7 rads of exposure (75 days of s t o r a g e ) . T h i s i s approximately t h e same t i m e pe r iod r equ i r ed t o wash t h e p r e c i p i t a t e p r i o r t o pumping it t o t h e s t o r a g e tank. During t h e washing p rocess , t h e s l u r r y w i l l con ta in 9 w t % s o l i d s and w i l l be subjected to t h e same irradiation dose that it will r ece ived d u r i n g storage. going i n t o t h e s t o r a g e t a n k w i l l have a s i g n i f i c a n t l y l o w e r y ie ld stress and cons i s t ency t h a n p r e d i c t e d from simulated, non-irradiated s l u r r i e s .

Table I1 lists r e s u l t s for three d i f f e r e n t s l u r r y batches. Two of t h e s l u r r y batches w e r e prepared us ing an excess of potassium i o n du r ing t h e p r e c i p i t a t i o n , and one batch w a s prepared us ing a n excess of t e t r a p h e n y l b o r a t e .ion (see Appendix B f o r detai ls of t h e p r e p a r a t i o n s 1 It w a s . thought t h a t t h e method' of p r e p a r a t i o n of t h e s l u r r y might e f f e c t - t h e i n i t i a l y i e l d stress and subsequent i r r a d i a t i o n e f f e c t , However, t h e two s l u r r i e s behaved i n

*

The c a l c u l a t i o n of t h e radiat ion dose i s given i n

Thus, it i s very l i k e l y t h a t f r e s h s l u r r y

e s u b s t a n t i a l l y t h e same way. .

E f f e c t of p H

The pH of t h e s l u r r y does n o t t o have a s i g n i f i c a n t e f f e c t on i t s

-4-, M. A. EBRA DPST-85-926 November 5 , 1985

,

r h e o l o g i c a l p r o p e r t i e s . Two experiments were run: i n t h e f i r s t , ~

t h e pH of a p non- i r r ad ia t ed s l u r r y w a s a d j u s t e d downward using formic acid; and i n t h e second, t h e pH o f an i r r a d i a t e d s l u r r y w a s a d j u s t e d upward w i t h sodium hydroxide (see Table 1) . t h e change i n pH had no e f f e c t on t h e , r h e o l o g i c a l p r o p e r t i e s . known t h a t t h e pH of t h e s l u r r y decreases from an i n i t i a l value of 12.8 t o a l o w of 9.5 when it is i r r a d i a t e d f o r t h e equiva len t of t h r e e yea r s of t a n k farm s t o r a g e (Ref . 4 ) . The pH appears t o s t a b i l i z e a t 9.5 due t o t h e b u f f e r i n g action of t h e decomposition products . cause of t h e decrease i n y i e l d stress and cons is tency s i n c e o the r systems are known which are pH s e n s i s t i v e (Ref. 5 ) .

I n both cases, It i s

It w a s thought t h a t t h i s change i n pH could have been t h e

S e t t l i n q Characteristics and Visua l Appearance

The s e t t l i n g p r o p e r t i e s of i r r a d i a t e d s l u r r i e s are considerably. d i f f e r e n t from non- i r r ad ia t ed s l u r r i e s . tendency t o settle or compact when al lowed t o s tand . trap air, which causes foaming, and may a l s o cause t h e p r e c i p i t a t e t o f loa t even though t h e c r y s t a l s are more dense than water or d i l u t e s a l t s o l u t i o n s (Ref. 6). The ease with which a i r i s trapped may be due t o t h e hydrophobic na tu re of t h e i n s o l u b l e . t e t r a henyl- b o r a t e s a l t s . ( 0 . 3 2 y e a r s s t o r a g e ) , t h e s l u r r y s lowly settles t o approximately 20 w t 8 s o l i d s . s e t t l i n g or t h e f i n a l w t % -soli.ds.

A 1 0 . w t % s l u r r y has l i t t l e It tends t o

However, after a n i r r ad ia t ion dose of 4 . x l a ? rads ,

I

Longer i r r a d i a t i o n s do no t i n c r e a s e t h e rate of

Under microscopic examinat ion, t h e i n d i v i d u a l c r y s t a l s i n t h e s l u r r y appear t o b e f l a t p l a t e s , from 0 . 1 t o 0.5 microns i n t h i c k n e s s and from 0.5 t o 5 mic rons i n diameter (Pig. 3 ) . The f r e s h KTPB s l u r r y a p p e a r s t o be composed of agglomerates o f . t h e s m a l l c r y s t a l s . The s t a b i l i t y of t h e s e agglomerates is probably t h e cause of t h e high y i e l d stress and v i s c o s i t y . I r radiat ion appears t o d i s p e r s e (or de-agglomerate) t h e o r i g i n a l s l u r r y stress and v i s c o s i t y . I n t h e irradiated s l u r r y , t h e agglomerates are smaller and many more i n d i v i d u a l c r y s t a l s are p resen t . Based on a l i m i t e d v i s u a l examinat ion, t h e i n d i v i d u a l c r y s t a l s appeared t o be t h e same s i z e and shape a f t e r be ing irradiated.

The mechanisn; by which i r r ad ia t ion d i s p e r s e s t h e c r y s t a l s i s not known, but it may be due t o t h e small amounts of decomposition products formed. and phenylboric acid) are p o l a r molecules and may be adsorbed on t h e c r y s t a l s u r f a c e s , making them less hydrophobic and more hydrophi l ic . I n view of t h e i n s e n s i t i v i t y of t h e r h e o l o g i c a l p r o p e r t i e s t o i o n i c s t r e n g t h of t h e s o l u t i o n (i.e., washed and unwashed s l u r r y ) 8 it i s u n l i k e l y t h a t t h e high y i e l d stress is caused simply by i o n i c double layer e f f e c t s .

t he reby reducing t h e y i e l d

Two of t h e major decomposition products (phenol

.

M. A. EBRA - -5- DPST-85-926 November 5 , 1985

Rheology of S l u r r y Mixtures . .

I n the planned tank farm operations, batches of washed s lur ry w i l l be added t o t h e storage t a n k approximate ly every four months. S l u r r y w i l l ’ b e removed from t h e s t o r a g e t a n k i n small ba t ches (3430 g a l ) e v e r y 4 3 hours. The re fo re , t h e s l u r r y be ing removed is a mixture of batches which have r e c e i v e d dif f e r<en t r a d i a t i o n exposures. The behavior of mix tu res w a s also i n v e s t i g a t e d us ing t h e same s i m u l a t e d s l u r r i e s d i s c u s s e d above. The r h e o l o g i c a l p r o p e r t i e s o f t h e m i x t u r e s are listed i n Table 111. The t e r n a r y mix tu re #3 i s a n approximate s i m u l a t i o n of t h e c o n t e n t s of . the s l u r r y storage tank. The obse rved y i e l d stresses for m i x t u r e s w e r e s l i g h t l y less than , b u t v e r y close to , t h e simple average of t h e y i e ld stresses of t h e component parts of t h e mixture . However, t h e cons i s t ency of t h e mixtures were, i n a l l cases, much h igher t h a n t h e c a l c u l a t e d . average. t h e cons i s t ency of t h e most v i scous component.

E f f e c t of Sodium T i t a n a t e

The presence of sodium t i t a n a t e does no t have a n e f f e c t on t h e r h e o l o g i c a l ’ p r o p e r t i e s of non- i r r ad ia t ed slurries ( R e f . 11, nor does i t s presence s i g n i f i c a n t l y affect t h e changes caused by i r r a d i a t i o n . Table I V l ists t h e p r o p e r t i e s of irradiated s l u r r i e s which con ta ined 0.4 w t 8 sodium t i t a n a t e . Th i s is t h e average t i t a n a t e l e v e l expected d u r i n g f u l l scale o p e r a t i o n s ( R e f . 2 ) . Although t h e i n i t i a l s l u r r y h a s a lower y i e l d stress and h ighe r cons i s t ency t h a n o t h e r b a t c h e s of s l u r r y , t h e p e r c e n t change i n t h e s e p r o p e r t i e s due t o i r r a d i a t i o n w a s ve ry similar.

I n fac t , t h e c o n s i s t e n c i e s of mix tu res were very close t o

Ca lcu la t ed Rheo log ica l P r o p e r t i e s f o r Tank Farm S l u r r i e s

Under anticipated o p e r a t i n g c o n d i t i o n s for t h e in- tank precipitation process , a r a n g e of r h e o l o g i c a l properties are expec ted i n t h e s l u r r y s torage tank . t h e yield stress and c o n s i s t e n c y of t h e s l u r r y i s t h e r a d i a t i o n dose it h a s r ece ived . l eve l i n t h e s l u r r y , and t h i s i s expected t o va ry s i g n i f i c a n t l y from ba tch t o b a t c h . The s t r o n t i u m v a r i a t i o n s can be neg lec t ed because more t h a n 99% of t h e t o t a l r a d i o a c t i v i t y i n t h e s l u r r y is due t o cesium-137 . A second c o n s i d e r a t i o n is t h e i n i t i a l r h e o l o g i c a l p r o p e r t i e s of t h e s l u r r y . I n p rev ious tests ( R e f . I ) , t h e y i e l d stress of s i m u l a t e d s l u r r i e s have been as high as 250 t o 300 dynes/cm2 w i t h c o n s i s t e n c i e s as high as 50 cp. percentage changes i n yield stress and c o n s i s t e n c y reported above, it i s p o s s i b l e t o c a l c u l a t e expected s l u r r y properties a t d i f f e r e n t cesium levels.

The m o s t s i g n i f i c a n t variable i n de te rmining

The dose is d i r e c t l y p r o p o r t i o n a l to t h e cesium

Using t h e

Table V l ists the rheological p r o p e r t i e s expected a t d i f f e r e n t cesium l e v e l s u s i n g t h e fo l lowing assumpt’ions:

M. A. EBRA -6- DPST-85'-926 November 5 8.1985

o The i n i t i a l s l u r r y has a y i e l d stress of 300 dynes/cm2 and c o n s i s t e n c y of 50 cp.

~

o The s l u r r y r e c e i v e s a r a d i a t i o n dose dur ing t h e 60 days of p r e c i p i t a t e washing .

o The s t o r a g e t a n k c o n t e n t s can be 'approximated by a t h r e e component mixture .

o The decrease i n y i e l d stress and cons i s t ency f o r a 300 dynes/cm2 s l u r r y is p r o p o r t i o n a l l y t h e same as for t h e 210 d y n e s / & ? s l u r r y r e p o r t e d above .

o The y i e l d stress of a mixture is t h e average of t h e components b u t t h e cons i s t ency is equa l t o t h e cons i s t ency of t h e m o s t v i scous component. -

The average cesium level expected for a 1 0 w t % KTPB s l u r r y i s 36 c u r i e s / g a l . . Based o n t h e assumptions above, t h e expected y i e l d str&s of a mixture w i t h t h i s r a d i o a c t i v i t y l e v e l i s only 20 dynes/cm2 and t h e expected cons i s t ency i s 11 cp. Even i f it is assumed t h a t t h e s l u r r y i s added t o t h e s t o r a g e t a n k wi thout r e c e i v i n a r a d i a t i o n dose, t h e y i e l d stress would only be 84 dynesicmj and t h e cons i s t ency 50 cp. t h a n average , t h e r h e o l o g i c a l p r o p e r t i e s of t h e stored s l u r r y r a p i d l y approach t h o s e of water. For lower than average cesium l e v e l s , t h e y i e ld stress and cons i s t ency do i n c r e a s e , b u t do no t begin t o approach t h e 300 dynes/& and 50 c p level even a t 28% of t h e average expec ted cesium.

For cesium levels h igher

Based on t h e s e c a l c u l a t i o n s , it does n o t seem l i k e l y t h a t t h e pumping system u s e d , t o transfer t h e s l u r r y t o t h e DWPF w i l l have t o handle a s lur ry which has a y i e l d stress greater khan 1 0 0 dynes/& and a cons i s t ency greater than 30 cp.

EXPERIMENTAL

The potassium t e t r a p h e n y l b o r a t e s l u r r i e s were prepared us ing sodium , t e t r a p h e n y l b o r a t e from t h e 1983 f u l l scale in- tank demonstrat ion a t

SRP. The s l u r r i e s w e r e irradiated i n g l a s s con ta ine r s us ing t h e Co-60 source i n b u i l d i n g 774-A. The nominal r a d i a t i o n f i e l d i n t h e source was 2.98 x 106 rads /hr on September 6, 1985. r h e o l o g i c a l p r o p e r t i e s of t h e s l u r r i e s were measured using a Haake Rotovisco RV-12 w i t h a n M150 measuring d r i v e u n i t and T I sensor system. from 0 t o 300 sec-l and back to 0 ( u s i n g a Haake P G 1 4 2 programmer). c a l c u l a t e d u s i n g a Hewlett-Packard HP 85 computer and t h e Haake ?Rota t ion" software package.

The

T h e 'shear stress was .measured as t h e shear 'rate w a s varied

The s h e a r stress and v i s c o s i t y of t h e samples were

/

'M. A. EBRA -7- DPST-8 5 -92 6 November 5 , 1985

QUALITY ASSURANCE

Quality assurance of t h e new data r e p o r t e d h e r e is covered by DPSTQA-85-2-25, " Q u a l i t y Assurance R e v i e w : Decontamination of S o l u b l e Defense Waste by In-Tank P r e c i p i t a t i o n Process ing ," March 4 , 1985 , and by DPSTQA-85-2-33, " Q u a l i t y Assu rance R e v i e w : Sludge C h a r a c t e r i z a t i o n , "August 1 5 , 1985. The data are recorded i n Labora tory Notebook DPSTN-4274.

M, A, EBRA DPST-85-926 '

-8- , November 5, 1985

References

1. M. A. McLain and I, D. .Goren, "Rheology of Non-radioactive Simulant of Concentrated Te t r apheny lbora t e P r e c i p i t a t e , " DPST-84-401, March 30, 1984.

2. Defense Waste Process ing F a c i l i t y Basic Data Report (Rev, 91) ,

3. B. A, Hamm, "Rheology of P r e c i p i t a t e from F u l l S c a l e In-Tank

Appendix 1, DPSP-80-8 27, 'October 18 , 1984.

Demonstrat ion," DPST-83-955, October 28, 1983. -

4'. D. D, Walker, " I r r a d i a t i o n E f f e c t s on t h e Compositi'on of Potassium Tet raphenylbora te S l u r r i e s , " DPST-85- i s s u e d .

H. B. Weiser, I n o r q a n i c Colloid Chemistry, V o l 11, John Wiley and Sons, N e w York, 1935, p 66.

, t o be

5 .

6. J. O z o l s , I. Tetere, S. Viba, and A. I e v i n s , Latv, PSR Zina t .

7. E. D. Arnold, "Handbook of S h i e l d i n g Requi rements and Radia t ion

A d a d . V e s t i s , K i m . Ser, 1975, (51 , 517-20,

C h a r a c t e r i s t i c s of I s o t o p i c Power Sources f o r Terrestrial Marine and Space App l i ca t ions , " A p r i l 1964, ORNL-3576.

M . A. EBRA .-9- DPST-85-926 *

November S r 1985

APPENDIX A

C a l c u l a t i o n of Radiat ion Dose t o t h e S tored KTPB S l u r r y

The potass ium t e t r a p h e n y l b o r a t e s l u r r y which i s t o be s t o r e d i n Tank 49 w i l l c o n t a i n an average of 36 curies of Cs-137 pe r g a l l o n of s l u r r y (Ref, 21 , T h i s i nc ludes t h e 10% of t h e cesium which i s r e c y c l e d frcm t h e melter off-gas 'system i n t h e DWPF back t o t h e tank farm. The decay energy of Cs-137 i s 4.84 watts/kCi- (Ref. 7 ) and inc ludes b o t h t h e b e t a (Cs-137 1 and gamma (Ba-137 1 c o n t r i b u t i o n s . S i n c e cesiurc-137 comprises more t h a n 99% of t h e t o t a l c u r i e c o n t e n t of t h e slurry, t h e decay of other r ad ionuc l ides can be omitted. It is also assumed t h a t all of t h e energy of t h e radioactive decay i s d e p o s i t e d w i t h i n t h e s o l u t i o n . Thi s i s a good assumption f o r a large t a n k where t h e energy d e p o s i t e d i n t h e walls is n e g l i g i b l e .

7 sec Y r

. 3,1536 x 10 - . w a t t s . 4.84 .k-ci . C i

1 gal 1 m l 3 rads 36 gal

=- 1.45 x l o 8 - 3,785.4 Ig 6.24 x 1y3 e V / g - Y=

M. A. EBRA DPST-8 5 - 92 6

, -10- November 5, 1985

APPENDIX B

P r e p a r a t i o n of KTPB S l u r r i e s

The 1 0 w t % KTPB s l u r r i e s u sed for t h e s e experiments were prepared by t w o d i f f e r e n t methods. S l u r r i e s prepared by J. P. Doherty a t TNX started w i t h a n aqueous s o l u t i o n of potassium sa l t s t o which a s o l u t i o n of sodium t e t r a p h e n y l b o r a t e w a s added, The potassium i o n was i n excess and s u f f i c i e n t sodium t e t r a p h e n y l b o r a t e w a s added t o produce a 10 w t % s l u r r y w i t h o u t a c o n c e n t r a t i o n ( f i l t r a t i o n ) s t e p . The s l u r r i e s prepared by D. D. Walker started w i t h an aqueous s o l u t i o n of NaTPB t o which w a s added a s l i g h t d e f i c i e n c y of potassium i o n . conqentrate t h e s l u r r y t o 1 0 w t %, A comparison of t h e f i n a l ( t h e o r e t i c a l ) ' composi t ion is shown i n t h e Table below.

The K+-&cess s l u r r y w a s p repared by d i s s o l v i n g t h e fo l lowing chemica ls i n 168 .pounds of water i n a 55 gal lon drum: KNO3, 2053 g; KOH, 788 g; Na2SO4, 361 g; K2CrO4, 5.9 g; CsNo3, 139 g; sodium a l u m i n a t e (Na2O0A1203.3H20), 305 g; KN02, 627 g; K2CO3, 412 9; K2HPO4, 20 g; K2C204.H2O, 1 2 . 1 g; and NH4OH (28% aqueous s o l u t i o n ) , 75 g. kg of NaTPB were dissolved i n 168 pounds of water. s o l u t i o n w a s t h e n pumped i n t o t h e potassium s a l t s o l u t i o n wh i l e a g i t a t i n g .

The TPB'-excess s l u r r y w a s p repared by d i s s o l v i n g t h e following chemica ls i n 4.5 liters of water: N a N 0 3 , 11.9; NaN02, 8.97 g; NaOH, 1 4 . 4 g; and 97.41 g NaTPB. I n a second c o n t a i n e r , 28.22 g KNO3 were dissolved i n 500 ml water . so lu t ion w a s added s lowly w i t h s t i r r i n g t o t h e t e t r a p h e n y l b o r a t e s o l u t i o n , producing a d i l u t e s l u r r y . The s l u r r y w a s concen t r a t ed t o 1 .0 l i ter by f i l t r a t i o n .

Th i s method r e q u i r e d a f i l t r a t i o n s t e p t o

I n a second c o n t a i n e r , 15.25 The NaTPB

I

The potassium n i t r a t e

, e . ..

M. A. EBRA DPST-85 -92 6

-11- November 5, 1 9 8 5

TABLE 'A

Calculated Composition'of RTPB S l u r r i e s

- Concent ra t ion

Component TPB' E x c e s s K+ E x c e s s Basic Data Report* .

- I n s o l u b l e s ( w t % ) KTPB 9.9 9.3 8.9

- -26 04 - - 01 NH4TPB

- - 04 H g ( C g H 5 ) N a T i t a n a t e

CsTPB - 019 0 1

T o t a l 9 - 9 . 9.75 9.9

S o l u b l e s (molar 1 Na+ ,

NO3- .N02- 0 H'

Kf 017 -

%!

.077

.024 ,066 00010

.32

.034 -12 6

,092

,015 00002 ,017 ,018 ,0007 .0004

' - 0 4 4

-

,255

,084 ,026 . ,072 ,0023 ,0060 .00014 .013 .0007 .0004 0009

-

-* Ref . 2.

M. A. EBRA -12- DPST-85-926 November 5, 1 9 8 5

/ TABLE I

P r e d i c t e d and Observed P r o p e r t i e s of Radioactive KTPB S l u r r i e s

Weiqht 8 Insoluble S o l i d s P red ic t ed* Observed P red ic t ed Obs’er ved Yield Stress (dynes/cm2 1 Consistency (cp)

7 154 0 - 27 4 1 2 . 340 7 2 - + 34 7 58 34 - + 1 7

* B a s e d on R e f . 3. ’

TABLE 11

R h e o l o q i c a l P r o p e r t i e s of Irradiated KTPB S l u r r i e s

Sample*

S l u r r y tl (K+ excess)

Slurry # 2 (K+ excess)

S l u r r y #3

R a d i a t i o n Dose E q u i v a l e n t Storage Y i e l d Stress ( rads 1 (years) ( dynes/cm2 1

0 0 210 + 1 0 96 10 1.3 x 107 0.093 -

#7.3 x 107 0.50 0

2.9 x l o 8 2.02

2.4 107 0.17 42 4.8 x 1 0 7 0.33 6

0 0

1.5 x l o 8 1.03

0 0 240 (26°C) 19’5 (39°C)

0 (26°C) 0 (40°C)

2.2 x 1 0 8 1.51

* o 0 (pH = 1 2 . 5 ) . 230

C o n s i s t e n q (cp)

26 + 3

7 + 6 - 5 4 3 3

9 2 2

6 2 36

9 4

9 5 - (TPB exces>s) ( p H = 9 .1 ) 27 0 1 7 0

1.8 107 0.12 59 3 6 . 4 . 7 x 107 . 0.32 ( p H - = . 1 1 . 6 ) 14 1 9

7.1 x 107 0..-49 1.4 x l o 8 , 0.99

(pH = 1 3 . 0 ) . 1 3 2 1 0 . 1 1 + 4 - 6 . 15 3 13

2 . 2 . x 108 1 . 5 2 1 1 6

* See Append ix B fo r methods of s l u r r y preparation. Slurries #1 a n d #2 c o n t a i n e l approximately ‘9.0-9.3 w t % i n s o l u b l e so l ids , s l u r r y #3 c o n t a i n e d 9.8 w t % KTPB

M. A. EBRA -13-

TABLE I11 .

Rheological Properties of S l u r r y Mixtures

DPST-85-926 November 5 , 1985

Fraction of M i x t u r e Mixture (volume % 1

1 50% 50%

, Dose Equ iva len t Y i e l d Stress. (years) (dynes/cm2 1

0.0 ~ 0.093

- - 210 96

Cons i s t enc (cp)

26 9

2 50 % 50%

0.0 0.48

210 6

26 16

3 33% 33%

- 34%

0.0 1.03

' 2.02

210 0 0

26 3 3

TABLE I V

Rheoloqica l Properties of KTPB S l u r r i e s Conta in ing Sodium T i t a n a t e

Rad ia t ion Dose (rads 1

0.0 (w/o t i t a n a t e )

0.0

1 . 4 x 107

6.9 x 107

Equiva len t Storage (years)

0.0

0.0

0.094

0.48

Y i e l d Stress (dynes/cm2)

. 172

17 7

. 63

6

Consis tency (cp)

4 2'

42

24

16

M. A. EBRA i

, -14-

TABLE V

DPST-85-92 6 November 5, 1985

Calculated Rheoloqica l P r o p e r t i e s of KTPB S l u r r i e s

C e s i u m leve l ( C i / q a l )

36

Mixture

33% with 0- y e a r s exposure 3.3% wi th 1 year 33% with 2 y e a r s .

Y i e l d S t r e s s Cons is tency (dynesYcm2 1 (CP)

84 . 50

36 33% w i t h 0.2 years exposure 20 11 33% wi th 1.2 years 33% wi th 2.2 years

. . . . . . . . . . . . . . . . . . . . . . . . . - . - - - - - - - - - - /

10 33% wi th 0.2 years exposure 80 30 33% w i t h 1 .2 years~ 33% with-2 .2 years

- - - - - - - - - - - - - - - - - - - -__.______________

100 33% wi th 0.2 y e a r s exposure 0 7 33% wi th 1 . 2 years 33% with 2.2 years .

,

.. A. EBRA I -15-

Figure 1

November 5, 1985

Yield Stress of Irradiated 10 Wt % KTPB Slurries

.o ' .2 - 4 .L . .8 1.0

Irradiation Dose (equivalent years of storage)

Figure 2

Consistency of Irradiated 10 Wt % KTPB.Slurries

40

I

' 0 I I 1 I f .

.o ' .2 .4 -6 .e . 1.0

Irradiation Dose (equivalent years of storage)

, M. A. EBRA -16- Figure 3

’ Potassium Tetraphenylborate Crystals

Y 1 U A V J J & V

November 5 t 1985

,