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FUEL CHEMISTRY DIVISIONANNUAL PROGRESS REPORT FOR 1988
S. Vaidyanathan
1991
GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION
oo
Ua:<CD
FUEL CHEMISTRY DIVISION
ANNUAL PROGRESS REPORT FOR 1908
EdiLecl by
S. VaidyanaLhan
BHADHA ATOMIC RLSLAROI CLN7KIHOMHAY, INDIA
199 I
BARC/1991/P/002
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10 Title and subtitle : Fuel Chemistry Division : annualprogress report for 19BB
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158 p., 61 tabs., 13 figs.
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:Fuel Chemistry DivisionAtomic Research Centre,
Bhabha Atomic ResearchBombay - 400 0B5
Fuel Chemistry Division,
, BhabhaBombay
Centre,
BARC, BDHIIJU
Department of Atomic Energy
Government
July 1991
August 1991
Contd... <i i)
(ii)
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InformationAtomic Research
60 Abstract : The progress report gives the brief descriptions ofvarious activities of the Fuel Chemistry Division of BhabhaAtomic Research Centre, Bombay for the year 1988. Thedescriptions of activities arm arranged under the headings :FuelDevelopment Chemistry, Chemistry of Actinides, Quality Controlof Fuel, and Studies related to Nuclear Material Accounting. Atthe end of report, a list of publications published in journalsand papers presented at various conferences/symposia during 1988is given.
73 Keywords/Descriptors : PROGRESS REPORT; RESEARCH PROGRAMS;MICRDSPHERES; THORIUM OXIDES; URANIUM OXIDES; PLUTONIUM;URANIUM; SOLVENT EXTRACTION; ION EXCHANGE MATERIALS; RESINS;QUANTITATIVE CHEMICAL ANALYSIS; NUCLEAR FUELS; ACCOUNTNG;QUALITY CONTROL; BARC; CALIBRATION STANDARDS
71 Class No. : INIS Subject Category : B16.10
99 Supplementary elements : The previous progress report waspublished as BARC-1516 covering theperiod 19B7
( i )
PREFACE
The activities of the Fuel Chemistry Division during 1988 are
presented in this Annual Report in four sections.
The first section, Fuel Development Chemistry, deals with
sol-gel processes for the synthesis of microspheres such
as DC, (U,Ce)C and ThO2 and non-nuclear ceramics. Also included
in this section are the measurement of some of the
thermodynamic parameters of materials like nickel telluride,
sodium zirconate, caesium chromate, caesium molybdate etc.
which are likely to be encountered in operating reactors.
The second section, Chemistry of Actinides, deals with i,he
solid state, sol'ition and process chemistry of actinides. Solid
state reactions and phase studies are the areas of work covered
in solid state chemistry. In solution chemistry, solvent-
extraction studies with Di-2 ethylhexyl phosphoric acid
(D2EHPA), long chain secondary amine Amtaerlite LA-1 and MOFPA
and ion-exchange studies from mixed solvent media have been
covered. Studies in Process Chemistry include evaluation of
different anion exchange resins for plutonium processing,
recovery of U-233 from phosphate containing aqueous waste,
recovery and purification of plutonium from fuel fabrication
scrap etc.
i i )
T h e t h i r d s e c t i o n , C h e m i c a l Q u a l i t y C o n t r o l of N u c l e a r F u e l s
d e a l s w i t h a n a l y t i c a l m e t h o d s , p r i m a r y c i e m i c a ) s t a n d a r d s a n d
analytical services. Analytical methods cover the developmental
work on electrochemical, titrimetric and mass spectrometric
methods for the chemical quality control of nuclear materials.
Preliminary studies on the preparation and characterisation of
primary chemical assay standards for uranium and plutonium are
reported.
In the fourth section, Nuclear Materials Account ing,an overview
of NUMAC database maintained for the nuclear materials
accounting ir. all the DAE Facilities has been given.
The report also includes a list of papers published in
Journals and presented at various Con f er ences -'Sy rr.pos i a..
The Editor expresses his sincere thanks to Dr. D.D.Sood,
Head, Fuel Chemistry Division for his valuable suggestions in
the preparation and organisation of this report. He also
highly appreciates the cooperation and help rendered by
Sri Satya Jyothi in compilation of this report.
( ii i
CONTENTS
PREFACE ( i )
1. FUEL DEVELOPMENT CHEMISTRY 1
1.1 Soi-Gel Process Development. 1
1.2 High Temperature Thermodynamics. 20
2. CHEMISTRY OF ACT IN IDES 35
2.1 Solid State Chemistry. 35
2.2 Solution Chemistry. 47
2.3 Process Chemistry. 76
3. CHEMICAL QUALITY CONTROL OF FUELS 99
3.1 Analytical Methods. 99
3.2 Primary Chemical Assay Standards. 131
3.3 Analytical Services. 139
4. NUCLEAR MATERIALS ACCOUNTING 142
5. PUBLICATIONS 146
FUEL DEVELOPMENT CHEMISTRY
1. 1 SOL-GEL PROCESS DEVELOPMENT
1.1.1 SYNTHESIS OF URANIUM MONOCARBIDE MICROSPHERES BY
SOL-GEL PROCESS.
S.K. Mukerjee, J.V.Dehadraya, Y.R.Bamankar, V.N.Vaidya
and D.D. Sood.
Introduction
The present trend in fast reactors towards higher operational
temperatures, higher linear power rating, and higher breeding
ratio points towards the possible use of carbide as nuclear
fuel for future systems. Presently carbothermic reduction of
UO2 + PuO2 powders followed by grinding and pe11etization of
carbide powders is the established route for mixed carbide
fuel fabrication. Sol-ge! method of preparation of carbides
has several advantages over the conventional pellet route; as
it uses a minimum number of steps with carbothermic reduction
itself leading to dense particles and no grinding or milling
of reactive and pyrophoric powders is required.
Several reports^" 4-' have been written concerning the carbo-
thermic reduction of carbon containing oxide gel particles to
carbide. Al1 these reports deal with the reduction carried
out in two steps, first the reduction of UO3 to UO2 by
hydrogen followed by carbotherinic reduction. This was necessary
as the C/M ratio, approximately 3.5, required for direct
carbothermic reduction of the particles could not be obtained
because of difficulties in dispersion of large amounts of
carbon. The hydrogen reduction of UO3 itself is complicated
due to side reaction of hydrogen and moisture with carbon and
thus fixing of the carbide s to i ch i oine try becomes d i f f i c u l t . The
present work overcomes this problem as sufficient quantity of
carbon can be dispersed in the gel particles using proper metai
ion c o n c e n t r a t i o n by the use of gelation field d i a g r a m ^ ' ' and
C/M ratio around 3.5 can be obtained easily in the gel
par t ic1es.
Ex per i menta1
Internal gelation process and the gelation assembly used for
the p r e p a r a t i o n of gel particles have been described
e l s e w h e r e ^ - ' , M a x i m u m C/M ratio o b t a i n a b l e with standard feed
c o m p o s i t i o n is 3.3 as uranium molarity in such a s o l u t i o n is
1.2M and (HMTA, u r e a ) / u r a n i u m mole ratio is 1.4. Thus in the
present i n v e s t i g a t i o n s the uranium molarity in the feed
s o l u t i o n s was lowered. Uranyl nitrate solution (3M) was mixed
with a scliitior, of HMTA and urea c o n t a i n i n g finely dispersed
c a r b o n powder (United KAF) in cold c o n d i t i o n (0°C) to obtain
feed s o l u t i o n 1.1M in uranium and having (HMTA, ur ea ) / u ran i. urn
mole ratio of 1.5. The droplets of this s o l u t i o n were
contacted with hot silicone oil to obtain UO3 gel partic! ','F
with h o m o g e n e o u s l y dispersed carbon. Total 9 batches were
prepared and C/M mole ratio in the feed was varied between 3.45
to 3.50. The gel p a r t i c l e s were washed, dried ami heated in
a r g o n upto 300°C to remove m o i s t u r e , a m m o n i a and residua!
g e l a t i o n a g e n t s .
E x p e r i m e n t s on heat treatment were done on 50 g per bai-rh
scale in a tantalum carbide c r u c i b l e . Heating was
carried out in high temperature high vacuum tungsten heater
furnace. Initially UO3 was reduced to UUo by reaction
at 700°C. C a r b o t h e r m i c reduction of UO2 was initiated around
1200° C and soak time at various temperatures varied from 2 to
10 hrs. S i n t e r i n g was d o n e for 2 hours at 1700°C in argon. The
product was analysed chemically for oxygen uranium and carbon.
X - r a y d i f f r a c t i o n a n a l y s i s was d o n e t o i d e n t i f y t h e p h a s e s
p r e s e n t . The d e n s i t y was d e t e r m i n e d by s t e r e o p y c n o m e t e r .
R e s u l t s a n d D i s c u s s i o n
T h e r e s u l t s a r e s u m m a r i s e d i n T a b l e 1. In a l l c a s e s s i l v e r y
s h i n i n g a n d c r a c k f r e e m i c r o s p h e r e s w e r e o b t a i n e d . R e d u c t i o n
a n d s i n t e r i n g c a r r i e d o u t a t l o w e r t e m p e r a t u r e r e s u l t e d i n h i g h
o x y g e n c o n t e n t . T h i ? c o u l d h a v e r e s u l t e d b e c a u s e of s l o w r a t e
of r e a c t i o n a t low t e m p e r a t u r e s a s t h e p a r t i c l e s s i n t e r a n d
c l o s e t h e p o r e s a n d d o n o t a l l o w t h e r e a c t i o n t o go t o
c o m p l e t i o n . S i m i l a r r e s u l t s w e r e o b t a i n e d when t h e r e a c t i o n
was c a r r i e d o u t a t h i g h t e m p e r a t u r e a s t h e s i n t e r i n g b e c a m e
f a s t e r t h a n t h e r e d u c t i o n . A c o m p r o m i s e was made by i n c r e a s i n g
t h e t e m p e r a t u r e f r o m 1 3 0 0 t o 1 5 0 0 ° C a t a v e r y s l o w r a t e . T h i s
h e l p e d t h e r e a c t i o n t o p r o c e e d a t a s t e a d y r a t e a n d t h e p r o d u c t
c o n t a i n e d a r o u n d 1 0 0 0 ppm of o x y g e n . F u r t h e r w o r k i s i n
p r o g r e s s t o l o w e r o x y g e n c o n t e n t .
T h i s w o r k h a s s h o w n t h e p o s s i b i l i t y of u s i n g d i r e c t
c a r b o t h e r m i c r e d u c t i o n of g e l p a r t i c l e s t o o b t a i n U C
m i c r o s p h e r e s u s i n g i n t e r n a l g e l a t i o n p r o c e s s w i t h o u t r e s o r t i n g
t o a h y d r o g e n r e d u c t i o n s t e p .
R e f e r e n c e s
1. J . I . F e d e r e r a n d V . J . T e n n e r , O R N U T M - 6 0 8 9 1 1 9 7 8 1 .2 . K. B i s c h o f f , V. S c h e r e r a n d H. S c h u m a c h e r , S y m p o s i u m on S o l - G e l
P r o c e s s e s a n d R e a c t o r F u e l C y c l e , C O N F - 7 0 0 5 0 2 , U5M 1 970 )3 . K . B i s c h o f f , M.H. L l o y d and H, S c h u m a c h e r , So I - G e l P r o c e s s e s f o r F u e l
F a b r i c a t i o n 1AEA-161, I n t e r n a t i o n a l A t o m i c E n e r g y A g e n c y , V i e n n a , 95 ( 1 9 7 4 i4 . A . F a c c h i n i a n d P . G e r o n t o p u l o s , S o l - G e l P r o c e s s e s f o r F u e l
F a b r i c a t i o n , I A E A - 1 6 1 , I n t e r n a t i o n a I A t o m i c E n e r g y A g e n c y , V i e n n a , 9 5 . 1 1 9 7 4 ) .
5 . V .N. V a i d y a , S .K . M u k Q r j e e , J . K . J o s h i , R .V . Kamat and D. D. S o o d , J .N u c l . M a t . , 1 4 8 , 324 ( 1 9 8 7 ) .
6 . V .N. V a i d y a , R . V . Kamat and D.D. S o o d , R a d i o c h e m i s t r y D i v i s i o n Annua lP r o g r e s s R e p o r t f o r 1 9 7 8 , BARC-1114 ( 1 9 8 1 ) .
Table - 1
Preparation of UC raicrospheres from (UO3 + C) gel Particlesby Carbo-thermic Reduction alone.
Batchilo.
CB-2CB-4CB-6CB-6CB-6CB-8CB-9
c/uin gel
3.563.543.513.513.513.493.50
Temp°C
145014501450130013001300-15001300-1500
ReactiontimelhrsI
2.02.02.06.010.0in 4 hrsin 4 hrs
U
94.594.394.891.992.995.094.9
Product XOn
0. 180.210. 161.200.680. 110. 10
C
3. 125.014.887. 046. 494.834.81
Phase
uc,uc2l)C,VC2«uc,uc2UC,U0 2
UC,UC2
UCUC
* UC is the main phase.
1.1.2. S Y N T H E S I S OF (U,Ce)C M I C R O S P H E R E S C O N T A I N I N G 2 0 % OF Ce
BY SOL-GEL P R O C E S S .
S. K. M u k e r j e e , J . V. Deha d r a y a , Y.R. B a m a n k a r , V.N. Vaidys
and D.D. Sood.
This d i s c u s s i o n p r e s e n t s the studies on the direct reduction of
( U , C e ) 0 2 + x with carbon in vacuum for the preparation of
(U,Ce) m o n o c a r b i d e m i c r o s p h e r e s . This work was carried out
with a view to obtain experimental conditions suitable for the
pr e p a r a t i o n of (U,Pu)C, which is a potential nuclear fuel for
fast reactors. UO3+ C e O 2 m i c r o s p h o r e s containing 5 - 2 0 % of Ce
and 3.35 to 3.55 moles of carbon per mole of metal
prepared by internal gelation process.
Cerium nitrate solutions having NO^/Ce = 4.0F> us? prepared
by first precipitating C e as C e ( O H ) ^ from solution of
<NH4>2 Ce(N03>g then d i s s o l v i n g Ce(0H>4 i p required amount of
nitric acid. E x p e r i m e n t s on heat treatment were done on 50g.
per batch scale in tantalum carbide crucible. Heating was
carried out in high temperature high vacuum tungsten heater
furnace. Initially UO3 was reduced to UO2 by reaction
at 700°C. Carbothermic reduction of (U,Ce)02 initiated around
1200°C. Good product was obtained by increasing reaction
temperature steadily from 1300 - 1500°C in three hours.
Sintering was done for two hours at 1700°C in argon pressure of
lOOmbar. The product was chemically analysed for carbon,
oxygen and uranium. XRD analysis was done for the
identification of the phases present which showed complete
sol id solution formation between UC and CeC. The product
contained around 1000 ppm of oxygen. Further work is being
continued to reduce the oxygen content of the product.
1.1.3. KINETIC STUDY OF THE CARBOTHERMIC SYNTHESIS OF URANIUM
MONOCARBIDE MICROSPKERES. •
S.K.Mukerjee, J.V.Dehadraya, V.N.Va.dya and D.D. Sood.
Isothermal kinetics of the carbothermic reduction of porous
uranium oxide microspheres, having carbon black uniformly
dispersed in them was studied under vacuum and flowing gas from
1250 to 1550°C. The quantity of carbon monoxide gas evolved
with tin"- during reduction was used to determine the rate of
formation of the carbide. The results of these studies were
found to be useful in understanding the mechanism of the
carbothermic reaction involved, and in defining the heat
treatment scheme for preparation of good quality uranium
monocsrbide microspheres.
Ex per imenta1
The 'UO3 + C) gel particles were prepared by the process
described earlier. These particles were heated at 700°C under
vacuum to obtain (UO2 + C) particles. The k ' 1 etic studies were
carried out in a high temperatura/high vacuum controlled
atmosphere furnace. Experiments were done on 50g per batch
scale in tantalum carbide crucible. Carbothermic reduction of
UO2 takes place according to the following reaction.
UO2 + 3C > UC + 2 CO - (1)
The carbon monoxide measurements in the flowing gas conditions;
was measured by its oxidation to CO2 and absorption in
alkali. However under vacuum the rate of CO gas released from
the sample, Q(t), was calculated from the pressure inside the
reaction vessel at time 't', P(t) and the pumping speed 'S' of
the system using the following relation:
Q(t) = S . P(t)
Reaction ratio a was calculated by integrating Q(t) with
respect to 't'. The reaction ratio a is defined as,
« = (W£ - W ^ ) / ( W j - Wf)
where wj , w^ and Wf are initial weight, weight «t timo 't',
and final weight of the sample. The intermediate and the final
products were analysed chemically for carbon, oxygen and
nitrogen content. X-ray diffraction analysis was done to
identify the phases present.
Results
Typical data for the reduction carried out under flowing
purified argon and vacuum at 1450°C are given in Table-2.
At lower temperatures, the time required for completion of
more than 95 percent of the reaction was more than 20
hours. Two experiments were carried out at each temperature.
The data could be fitted in the equation -ln(l-o) = kt
(diffusion controlled). The energy of activation for tho
reaction under flowing gas was found to be 330 kJ.mol" .
For experiments carried out under vacuum,the best fit for the
results was obtained for the rate equation:
= kt (interface controlled).
Temperature dependence of the rate constants gave an activation
energy of 330 kJ . mo I ~ *•.
Discuss i on
The possible rate controlling mechanisms for the oarbothermic
reduction of spherical UO2 particles to 1>C has been
suggested by Lindemer et al t3^. Based on this model the
following rate controlling steps can be considered operative
for the conversion of UO2 to UC.
1) C > tC]yC at the surface.
2) IClyQ diffusion from surface to the UO2 - UC interface.
3) The reaction CC](jc + UO2 > UC + 2[0]UC at the
interface.
4) tOD^c diffusion to the surface of the sphere.
5) tO^uc + c > c o (8> a t the surface of the sphere.
6) Diffusion of CO gas through porous UC layer.
in which [X] denotes species X in solid solution.
Holmes et al^**] studied the conversion of 1.5 to 2mm
agglomerates (made from submicron carbon and UO2) to UC in
fluidised bed. L i ndemer ̂ 5 •* analysed his data and compared
total reaction time with the value theoretically calculated on
the basis of reaction governed by steps 2 and 4 or step 6. He
reported that the reaction appeared to be controlled by solid
s t a t e d i f f u s i o n p r o c e s s ( s t e p 4 ) a s t h e i n c r e a s e i n CO p r e s s u r e
d e c r e a s e d t h e r e a c t i o n r a t e . A i n s l e y e t a 1 *• ° ^ who c a r r i e d
o u t r e a c t i o n i n v a c u u m a l s o r e p o r t e d s o l i d s t a t e d i f f u s i o n a s
t h e r a t e c o n t r o l l i n g s t e p . T h e y a r e of t h e o p i n i o n t h a t s t e p 2
i s r a t e c o n t r o l l i n g , s i n c e i f s t e p 4 w e r e r a t e c o n t r o l l i n g t h i s
w o u l d r e s u l t i n f o r m a t i o n of s e s q u i c a r b i d e o r d i c a r b i d e u n d e r
v a c u u m a s s t e p 2 w o u l d b e r e l a t i v e l y r a p i d i n t h e o p p o s i t e
d i r e c t i o n .
T h e r e s u l t s o f t h e p r e s e n t w o r k i n d i c a t e t h a t t h e r e a c t i o n r a t e
i s d i f f u s i o n c o n t r o l l e d u n d e r f l o w i n g g a s c o n d i t i o n s b u t i t
c h a n g e s t o i n t e r f a c e c o n t r o l l e d u n d e r v a c u u m . U n d e r f l o w i n g
g a s c o n d i t i o n s d i f f u s i o n o f CO g a s t h r o u g h p o r o u s UC l a y e r
( s t e p 6 ) a p p e a r s t o b e r a t e c o n t r o l l i n g s i n c e f o r s o l i d s t a t e
d i f f u s i o n c o n t r o l l e d r e a c t i o n t h e m e c h a n i s m w i l l n o t c h a n g e
w i t h c h a n g e of r e a c t i o n c o n d i t i o n f r o m f l o w i n g g a s t o v a c u u m .
R e f e r e n c e s .
1. V.N. Vaidya e t a l ; J . Nuc l . Ma te r ; 148 (19871 324 .2 . T.B. Lindemer e t a l ; J . Amer. Ceram. S o c ; 52. , 2 3 3 ( 1 9 6 9 ) .3 . J , T . Holmes e t a l ; USAEC r e p o r t ANL - 7482, Argonne
N a t i o n a l L a b o r a t o r i e s , USA ( 1 9 6 8 ) .4 . T.B. Lindemer , Nuc l . Appl . T e c h n o l ; 9 , 7 1 1 ( 1 9 7 0 ) .5 . R. A i n s l e y e t a l ; New Nuc lea r M a t e r i a l i n c l u d i n g
N o n m e t a l l i c f u e l s , P r o c . IAEA, P r a g u e , 3 4 9 1 1 9 6 3 ) .6. B. S e r i n and R.T. E l l i c k s o n , J . Chem. Phys ; 9 , 7 4 2 ( 1 9 4 1 ) .7. W.D. Spence r and B. Top ley , J . Chem. Soc ;2633 ( 1 9 2 9 ) .8. D.P. S t i n t o n e t a! ; J . Amer. Ceram. Socj 6£ , 5 9 6 ( 1 9 7 9 ) .
Table - 2
Carbothermic reduction of UO2 particles undar flowing gas and vacuumat 1450°C. C/U = 3.5,(C = 12.48% and U = 70.22%). Pumping speed of thesystem = 1250 1it./min.
Under flowing gassample weight = 47.
Time
on50100150200
250300350400
450500550600
650700750800
Amount of CO2trapped g
0.752.234.105.466.70
7.708.459.199.69
10.0610.5610.9311.18
11.3011.5511.8011.92
50g
a
0.060.180.330.440.54
0.620.660.740.78
0.810.850.880.90
0.910.930.950.96
Timemin.
- 11- 6
0*1223
27303842
506380
Pit)mbar102
0.6510.020.015.010.0
8.57.04.53.5
2.01.00.6
Under vacuumsample weight = 54.35g
Q(t) Amount of CO2moles/min.
103
0.365.5811. 168.375.58
4.743.902.511.95
1. 110.550.36
ovolvedmoles
0.0230.0370.1200.177
0.1880.2020.2250.234
0.2510.2710.276
0000
0000.
0.0.0.
IX
.08
. 13
.42
.62
.66
.71
.79
.82
.88
.95
.97
Q(t) = (P(tl . 10'3 /1.03J (1250/22.4)tt From integration of Q(t), t curve.I Temperature H50»C.
10
1.1.4. PREPARATION OF ThO 2 MICROSPHERES BY INTERNAL GELATION
PROCESS.
N.Kumar, V.R. Ganatra, S.K. Mukerjee, V.N. Vaidya and
D.D. Sood.
The work on development of internal gelation process for the
preparation of ThO2 microspheres was continued. Som^
experiments were carried out to study the gelation behaviour
of formaldehyde denitrated thorium nitrate solution. Feed
solution (200 ml) was taken in a jacketted beaker and viscosity
of the feed solution was monitored as a function of
temperature. The change in appearance of the solution was also
noted. The temperature at which gelation of the solution
occured was termed as gelation temperature. For various feed
compositions (CTh3 = 1.1 to 1.4 b. R = 1.2 to 1.5) the gelation
temperature varied between 60 ± 10°C. Three types of gels were
obtained, namely, soft opaque (some cases resulted into phase
separation! hard opaque and trans 1uscent. A "gelation field
diagram* has been constructed, which can be used in selecting
feed compositions suitable for the preparatirn of good quality
microspheres.
Few batches were made with thorium nitrate solution
preneutraIized with NH4 OH solution. Feed compositions were
selected from opaque hard and transparent region of gelation
field diagram. The results indicated that for the same thorium
concentration the amount of gelation agents required was more
compared to the corresponding composition from gelation field
diagram. This is expected as ammonium ion being present in the
preneutralized feed solution would retard the gelation reaction
due to common ion effect.
11
1.1.5. NON-NUCLEAR CERAMICS BY SOL-GEL ROUTE.
R.V. Kamat, K.T. Pillai, N. Raghu, V.N. Vaidya and
D.D. Sood.
A. Preparation of Metal Alkoxides
Metal alkoxides readily hydrolise to form a sol and henoe serve
as the starting materials for obtaining a wide variety of high
technology ceramics such as PZT.PLZT, superconducting ceramics,
silica and alumina based ceramics of superior quality in the
form of bulk bodies as well as thin-films, coatings,
f i bres etc.
Commissioning of Karl Fischer Instrument
Realising the adverse effect of moisture in alkoxide synthesis
an old Karl Fischer instrument was recommissioned for the
routine moisture analysis of alcohols. Using anhydrous K2CO3
& CaO as desiccants the water content of the alcohols could be
kept below 3%. For complete drying of alcohols treatment with
calcium hydride will ba done shortly.
Preparation of Aluminium Iso-Propoxide
150 gms of aluminium iso-propoxide was obtained by refluxing
aluminium metal turnings with propanol at 78° C for 6 hours in
presence of HgCl2 catalyst. After distilling out the
propanol at 80°C, the alkoxide was distilled out at 115~120°C
at 50 mbar pressure. The yield was seen to improve from 45% to
greater than 90% by using small size Aluminium turnings and
mosture-free HgCl2 catalyst.
12
Preparation of Copper Iso-Propoxide
About 50g of copper iso-propoxide was prepared by the
reaction of Li iso-propoxide with anhydrous cupric chloride
obtained by careful heating of hydrated CuCl2 at 200°C in an
atmosphere of dry HC1 gas. By refluxing the 2:1 molar mixture
in moisture-free isopropanol, bluish green precipitate of
cupric iso-propoKide was obtained. This was freed from the
soluble salt of LiCl by repeated washing with iso-propanol and
then dried in vacuum (0.5 mm) at room temperature.
Preparation of Iso-Propoxides of Ca. Ba & Sr
With a view to prepare high Tc ceramic superconducting
materials by sol-gel route, the alkoxides of Ca, Ba and Sr were
made on a trial basis with a batch size of 15g. The metal rods
were cleaned and cut into pieces inside argon box and allowed
to react with moisture-free propanol by refluxing for 10 to 20
hours at suitable temperature till the reaction was complete.
The alcohol was then boiled off to get the respective metal
alkoxide in the form of powder with 70 percent yield. The
quality of the powder was not very good as the refluxing
etc. could not be done in argon box. Improved lots will be
made.
B. Prepration of Sols and Gels
Preparation of Alumina and Cupric Oxide Sols
These were made by the controlled hydrolysis of the respective
metal iso-propoxides. Nearly one litre of 0.05 molar stable sol
of cupric oxide was obtained which was then concentrated to
0.2M. Further concentration appeared to destabilise the sol.
One litre of 1.3 molar alumina sol was made by the procedure
described in the previous report.
13
Preparation of Thoria and Yttria Sols
The metal hydroxides were precipitated by adding ammonia
solution to the metal nitrate solution. The precipitate was
then washed repeatedly with dilute ammonia solution to wash out
the nitrate ions. The washing was then continued with
distilled water till the precipitate was free from ammonium
ions as tested by Nessler's reagent. The slurry was then
heated with vigorous stirring after adding a calculated amount
of nitric acid to cause peptisation. The dilute sols were ready
after about 30 to 40 hours of peptisation. Three litres of
yttria sol (0.1 M) and then ten litres of thoria sol (Q.1M)
were initially made. After curing at 100°C for about 100
hours, these could be concentrated to 0.4M yttria sol and
2.5M transparent thoria sol.
Burium Carbonate Sol
Attempts were mads to peptise BaC03 by vigorous stirring at
90°C in presence of baryta solution (0.1 mole ratio) and 0.1%
gelatine. There was no sol formation even after stirring for
24 hours.
Gels from Alumina, Thoria and Yttria Sols
Gel preparation studies described in previous report were
continued for alumina sol and these were extended to thoria
and yttria sols. Several gel monoliths in the form of discs cf
various sizes (10 to 20 mm dia and 2 to 12 mm height) were
obtained by chemical gelation of alumina sol in Tpflon molJs
in ammonia atmosphere followed by ambient drying. Unlike
alumina the thoria & thoria-yttria gels were found to crack
extensively during drying. Glycerol addition (1%) to the sol
was tried to achieve flexibility to the gels but without
success.
14
The dried alumina gels were crack-free and were having density
of around 3.5 gm/cc as determined by stereo pychnometer. Heat
treatment of these gels is planned to obtain high grade
ceramics.
C.Preparat ion of YBa2 CU3 0y_ x Ceramics
With the excitement over the discovery of high temperature
superconductivity, it was decided to prepare YBCO ceramics by
sol-gel route. As this route involves considerable effort
and time, work was initiated simultaneously by oxalate route
to gain some experience in this new field.
Preparation of YBCD by Qxalate Route
The precipitation pH,- of the oxlates of Y, Ba and Cu were
separately found to be 0.16, 0.53 and 0.31 respectively. The
metal salts were mixed In the mole ratio of 1:2:3 and
precipitated with oxalic acid. Th2 precip.tate was washed and
calcined at 500°C for 12 hours to get the oxide. This powder
was cold pressed into 9mm dia pellets and sintered at 950°C
for 20 hours in flowing oxygen. After slow cooling, (rate
:l°C/min) the pellets exhibited superconductivity at liquid
nitrogen temperature as shown by the ESR technique.
The 4-probe measurement revealed the sample to show zero
resistance at 81°K (Tc>. The XRD pattern showed the sample to
be multiphasic having several undesirable peaks which could
not be identified. More accurate control of precipitating
conditions seems to be necessary for obtaining a single phase
compound with higher T c.
15
P r e p a r a t i o n of YBCO by Sol-gel Route
The sols of y t t r i a & hydrous cupric oxide were made as
described earlier, whereas the attempt to peptise B a C 0 3 did
not succeed. H e n c e a slurry was prepared by mixing barium
i s o - p r o p o x i d e with sols of copper and yttrium in calculated
a m o u n t s needed for 1:2:3 c o m p o s i t i o n . P a r t of the slurry
was coated on d i f f e r e n t substrates (Cu.Ni, SS and a l u m i n a )
to get thin films. Remaining slurry was dried at roar.'
t e m p e r a t u r e to get a powder, which was pressed into 9mm dia
p e l l e t s . The pellets and coated s u b s t r a t e s were heat trf3?,tr>d
u p t o 8 6 0 ° C for various d u r a t i o n s . The coating peeled off
during heating. The pellets showed high resistance (mega o h m s ) .
A n o t h e r a t t e m p t was d o n e by refluxing the propoxides of Cu i, Bs
with y t t r i a sol and drying the slurry. The pellets were fired
at 950°C for 20 hours in oxygen but the X-ray d i f f r a c t i o n
pattern could not be matched with any of the 9 known phases of
Y.Ba.Cu and 0. Low temperature firing of the fresh pellets
seemed to be promising with the resistance level in the kilo
ohm range. The firing temperature was systematically changed
between 250 and 550°C. A minimum resistance of 10 kilo ohms
(by 2-probe) was noticed for the pellet fired at 470°C.
Improvements were not observed with prolonged heating in
oxygen. ESR technique showed a weak signal at 77°K. Further
work has been postponed awaiting the c o m m i s s i o n i n g of the
argon dry box facility.
D. P r e p a r a t i o n of PL2T C e r a m i c s .
Lead lanthanum z i r c o n a t e titanate <PLZT) ceramics are a range
of ferroe Iectric,optica1 1y active, transparent ceramic materials
based on the Pb-ZrO -TiO system. Work has been initiated on
the preparation of PL2T c e r a m i c s . Before going for the alkoxide
16
route, trial experiments are bBing done by the oxalate route in
ethanol medium. Starting with the titanium tetra chloride,
titanium nitrate solution was obtained by precipitating the
hydrous oxide with ammonia, washing it free from chloride and
then dissolving in nitric acid. The solution was assayed to
be O.2Z6M and was not very stable. Calculated amounts cf the
nitrate salts of Pb,La,2r and Ti were mixed in the aqueous
form to have the ratio X:65:35 where X is La(8%) and 65:35 is
the PbZrG"3 : PbTiO3 ratio. Ethanol ic solution of oxalic acid
was added to the nitrate mixture under controlled conditions
to get a co-precipitate of PL2T oxalate. This precipitate was
repeatedly washed with ethanol, dried at 120°C and then
calcined at 800°C for 2 hours to get the PLZT oxide,
(batch size 25g). The surface area of the oxalate and oxide
powders was found to be 11.7m^/g and 3.37m2/g respectively. The
cold pressed 9 mm dia button, after sintering at 1100°C for 6
hours, was not transparent. The crystalline nature of the
PLZT oxalate powder, as indicated by its XRD pattern, may be
due to the higher water content of ethanol. Work has been
planned to obtain amorphous oxalate which will be hot pressed
between 800-1100"C to obtain the transparent ceramic.
E. Preparation of Thallium based Superconducting Ceramic.
Several superconducting phases have been reported in
the Tl-Ca-Ba-Cu-0 system. These include the 2021, 2122 and 2223
phases where the numbers refer to Tl, Ca, Ba and Cu atoms
respective1y,in the formula unit.
The work on the preparation of TCBCO compounds by solid
state reaction of CaC03, BaCC>3, CuO and TI7O3 was taken up in
collaboration with Metallurgy Division. The difficulties arose
because of the volatility and high toxicity of T1203 and the
17
high reactivity of the final product with the cruciblu
(alumina, silica and even silver) thereby affecting the
superconducting properties. After several trial runs, these
problems have been largely overcome to get the
superconducting material showing an onset at 120°K and zero
resistance at 9B°K, as determined by 4-probe technique.
Several nominal compositions were tried and the heat
treatment scheme is being changed carefully in order to push up
the T to 125K. Partial substitution of thallium with lead,
has been planned and trial runs are in progress.
1.1.6. PROCESS DEVELOPMENT FOR TCE GELATION.
S. Suryanarayana , N. Kumar, V.N.Vaidya and D.D.Sood
With a view to minimize the process steps and to limit the
amount of liquids to be handled in glove box, work on modifying
the process parameters and equipment for internal gelation
process using Trichloroethylene as gelation medium has been
taken up. Introduction of Trichloroethylene as gelation
medium in place of silicone oil is advantageous as it
eliminates the carbon tetrach1 oride washing step and its
recovery by distillation.
Following are the details of work carried out pertaining to
process development for TCE gelation. Several trial runs were
carried out to arrive at optimum values for [II] in feed broth,
gelation time, gelation temperature, gelation column flow
parameters, curing time etc. for TCE gelation. The optimized
parameters are as follows:
18
( i ) C'J] in feed b r o t h
D r o p l e t s f r o m b r o t h s c o n t a i n i n g [U] less than 1.2 tend to f l o a t
on T C E and h e n c e n o t p r a c t i c a b l e in T C E g e l a t i o n . G e l a t i o n
t i m e r e q u i r e d for h i g h e r [IN is s l i g h t l y h i g h e r than t h a t of
1 o w e r C U ] .
(i i) G e l a t i o n m e d i u m t e m p e r a t u r e
A g e l a t i o n m e d i u m t e m p e r a t u r e of 6 0 ° C is f o u n d to be s a f e and
p r a c t i c a l in T C E g e l a t i o n for b o t h a v o i d i n g b o i l i n g of T C E as
w e l l a s f o r a c h i e v i n g g e l a t i o n t e m p e r a t u r e for c o m p l e t e
g e l a t i o n w i t h i n r e a s o n a b l e l e n g t h of the c o l u m n . T C E b e i n g a
low v i s c o s i t y l i q u i d h a s c o m p a r a t i v e l y b e t t e r h e a t t r a n s f e r
c h a r a c t e r i F t i c s a t 6 0 ° C t h a n s i l i c o n e oil a t s a m e t e m p e r a t u r e
a n d h e n c e c o u l d h e l p a c h i e v e g e l a t i o n t e m p e r a t u r e w i t h i n s h o r t
r e s i d e n c e t i m e of * 12 s e c o n d s in the c o l u m n .
(i i i) Ge1 a t i on t ime
S m a l l e r d r o p l e t s r e s u l t i n g f r o m 0.5 mm c a p i l l a r y c o m p l e t e l y gel
w i t h i n the l e n g t h of the c o l u m n but b i g g e r d r o p l e t s of 2 mm and
a b o v e r e q u i r e a c u r i n g t i m e of 2 0 - 3 0 m i n u t e s in hot T C E for
c o m p l e t e g e l a t i o n . G e l a t i o n time for d r o p l e t s w i t h h i g h e r LU1
is a c h i e v e d in o n e m e t e r c o l u m n as c o m p a r e d to s h o r t e r c o l u m n
of 7 5 cm s u i t a b l e f o r l o w e r [ U ] ,
( i v) G e l a t i o n c o l u m n flow p a r a m e t e r s
A s T C E is a very low v i s c o u s liquid c o m p a r e d to s i l i c o n s o i l ,
the c o l u m n f l o w s r e q u i r e d for s m o o t h o p e r a t i o n of c o l u m n
had to be r e a d j u s t e d by m o d i f y i n g the g e l a t i o n c o l u m n s i d e
limb. In the g e l a t i o n c o l u m n used for s i l i c o n e o i11 the h e i g h t
d i f f e r e n c e b e t w e e n m a i n limb o v e r f l o w and s i d e limb d i s c h a r g e
p o i n t w a s mai t a i n e d a s iiigh as 2 0 c m , by k e e p i n g the s i d e limb
d i s c h a r g e at a lower h e i g h t , to o v e r c o m e the r e s i s t a n c e of
h i g h v i s c o s i t y s i l i c o n e oil for p r o p e r f l o w s in m a i n limb and
s i d e limb. T C E , b e i n g a low v i s c o u s l i q u i d d i s c h a r g e s a* a
19
higher rate in such a set up. The diameter of the side limb was
decreased from 2.5cm to 1.5cm and the height increased to
2.5cm below the main limb overflow. This modification ensured
a proper flow in the main limb for maintaining temperature and
smooth removal of gelled product from the side limb.
Dried UO3 m i c r o s p h e r e s from TCE gelation are pale yellow in
a p p e a r a n c e and these m i c r o s p h e r e s upon reduction and sintering
resulted in crack free dense UO2 m i c r o s p h e r e s .
Further work on m o d i f i c a t i o n of 10 kg/day assembly to suit TCE
gelation process is in progrers.
1.1.7. OPTIMISATION OF HEAT TREATMENT SCHEME FOR OBTAINING
U 0 2 P A R T I C L E S SUITABLE FOR GEL PELLETISATION
S. S u r y a n a r a y a n a , N. Kumar, V.N.Vaidya and D.D.Sood
U O 2 particles suitable for gel pe11etization should be soft for
oasy crushing and also should retain their free flowing
c h a r a c t e r i s t i c s with particle integrity intact during
transfers. Pel Its obtained from such UO2 microspheres are
expected to be free from berry structure and should sinter to
required T.D. Addition of carbon as pore former and its
subsequent removal during heat treatment to create necessary
porosity for easy crushing is one of the ways known hitherto to
produce UO2 suitable for gel pe11etization.
In the present heat treatment scheme, it is aimed to exploit the
lattice expansion properties of uranium oxide in its phase
transformation during heat treatment to produce soft UO2
m i c r o s p h e r e s w i t h o u t resorting to pore forming additives.
20
Reduc t i on of UO3 to UO2 fol lowed by oxidation and reduction.
In these experiments. UO3 microspheres are first heated upto
500°C,in argon atmosphere,reduced for 1 hour between 500-600°C
in A1VH2 , subjected to a soak in oxygen at 650-700°C for one
hour and then again reduced in Ar/H2 between 700-500°C,
followed by stabilization in C 0 2 at 300°C. The UO2 product
obtained had high 0/M, reoxidised and heated up upon exposure
to atmosphere, gave a high tap density and was found to be
hard. Green and sintered pellets made from this product
had retained berry structure. In a later run of this redox
treatment, the stabilization at the end was done at 600°C. This
prevented reoxidation and heating up of product on exposure to
atmosphere but the quality of UO2 microspheres obtained from
this heat treatment was poor in that they are hard and pel lets
made from these microspheres retained berry structure in green
as well as sintered stages. It is planned to modify the heating
scheme in future runs and pursue the efforts to obtain soft
UO2 microspheres suitable for gel pe11etisation.
1.2 HIGH TEMPERATURE THERMODYNAMICS.
1.2.1. STANDARD MOLAR ENTHALPY OF FORMATION OF NICKEL TELLURIDE
Te00.405»
N.K Shukla, R. Agarwal, R. Prasad, K.N. Roy and
D.D. Sood.
In an operating fast reactor, tellurium is a major fission
product which can combine with the SS-316 cladding to form
compounds like FeTeQ.9. CrTej_i and Ni3Te2 and thus can cause
te11uriurn-induced liquid embrittlement of the SS-316
21
c I add ingl-1» 2 ] . A recent review on tellurides of first row
transition metals by Kleykamp and Chattopadhyayl-3^ reveals lack
of information on standard molar enthalpy of formation of these
tellurides. From the point of view of cladding corrosion, the
thermodynamic parameters of the compounds in equilibrium with
metal are of importance. Hence studies have been undertaken
to measure thermodynamic properties of these metal-rich
te1 1ur ides.
To start w ;th, nickel telluride (Ni3Te2> has been chosen. This
compound is called 8-phase and co-exists with metal(Ni) and has
a homogeneity range of 40.0 to 40.9 atom percent tellurium at
853K. At higher temperatures more nickel dissolves and the
homogeneity range extends from 37.5 to 42 atom percent
te 1 ur ium'-^ ̂. Whatever cal orimetric data exists in literature on
molar enthalpy of formation of Ni xTe^_ x is limited to
te 1 1 ur ium-r ich compounds'-'*'. Geiderikh et a l . ^ ' , have
estimated standard molar enthalpy of formation of Ni xTe^_ x
(x=0.333 to x=0.565J from EMF data. More recently Prasad
et a I . *• ̂ 3 and Vishwanathan et al.^'-* have estimated standard
molar enthalpy of formation of metal rich compounds < 6 -phase)
using vapour pressure data. In the present study, the standard
molar enthalpy of formation has been determined by direct
method using solution calorimetry.
The alloy was prepared by mixing high purity tellurium and
nickel. The mixture was sealed in an evacuated quartz ampoule
and heated at 1300K for 4 hours and then annealed at 1100K for
200 hours. The X-ray pattern of the alIoy agreed with the
reported pattern and the chemical analysis of the alloy
indicated the composition Nio.595^ e0.405 •
22
Enthalpy of solution of alloy ( N i g ^ g s T e g 4 0 5 ' ancl synthetic
mixture (0.595Ni + 0.405Te) were measured in 7M HNO3 ^ 5% H2SG4
acid mixture using an isoperibol solution c a l o r i m e t e r ^ ^ . The
standard molar enthalpy of formation of the alloy can. be given
by
T e 0 . 4 0 5 '
/\_ ,H {(0.595 Ni + 0.405 Te ) , S, 298.15°K)}— S o 1 m
T e 0 . 4 0 5 'S'
T h e e n t h a l p y of s o l u t i o n of s y n t h e t i c m i x t u r e a n d
t h a t of a l l o y w e r e f o u n d to he - ( 2 2 1 . 0 2 6 ± 0. 1 5 7 ) k j . m o 1"
a n d - ( 1 9 4 . 9 8 2 + 0 . 3 3 5 ) k J . m o 1 r e s p e c t i v e l y . T h e s t a n d a n i
m o l a r e n t h a l p y of f o r m a t i o n / _ \ . f H m < N i 0 5ql. T e Q 4 Q 5 , S, 2 9 5 . 15 ° K )
w a s f o u n d to b e - 1 2 6 , 0 4 4 + 0 . 3 6 9 ) k J . m o ! . T h e e n t h a l p y of
s o l u t i o n of t h e a l l o y , s y n t h e t i c m i x t u r e a n d the s t a n d a r d ino i 3 r
e n t h a l p y of f o r m a t i o n of a l l o y a r e g i v e n in T a b l e - 3 . T h e
/ \ H of a l l o y is g i v e n in T a b l e - -'i a l o n g w i t h t h er m
a v a i l a b l e l i t e r a t u r e d a t a for o t h e r c o m p o s i l iiuir; for d i r e c t0
c o m p a r i s o n . A p l o t o f / \ , H v a l u e s ( N i T e ) V:-. X i s1 ' — f m x 1 - x H 1s h o w n i n F i g . 1. It c a n b e s e e n f r o m thir- f i:;\;:e fh."if
Q
there is a sharp increase in - - f ^ ' 'J ' -^"l-y /3-phase)
values as X increases from D.f58 In 0. R3. Th i s is expected
since at. h i g h e r X ( > O . G 2 I t.he a c t i v i t y of Ni a p p r o a c h e s
u n i t y .
o£
XI
10
20
25
30
- V :
- • :- A :
- • :
— O :
-
-
- Ai
VISHWANATHAN ef a l .
PRASAD er a l .
K. C. MILLS
PRESENT WORK
GEIDERIKH et a l .
A
A
. . 1 . . . I ,
V
•
o
. 1
V
a
0.3 0.4 0.5 0.6
Fig 1. VARIATION OF - /\Hf(NiyTe).„)/kJ.molWITH XN.
-1
23
References.
1. Adamson.M.G., Aitken,E.A., Vaidyanathan,S., Nature.295,49(1962).2. Adamson, M.G., Aitken, E.A., J. Nucl. Mater., 130,375(1985).3. Kleykamp, H., Chattopadhyay, G., PSB-Ber 1549 (KI-II), Institut fur
Material und Festkorperforschung,KFK,GaibH, 1982.4. Mills, K.C., Thermodynamic data for inorganic Sulphides, Selenides and
Tellurides 1974.5. Geiderikh,V.A., Shevelva.S.N., Kutsenok,I.B., Krivosheya,N.S., Zh. Fiz.
Khim 54,1068(1980).6. Prasad.R., Iyer,V.S., Venugopal, V., Sundaresh, V., Singh,2. Sood, D.D.,
J. Chem. Thermodynamics , 19.,891 (19871.7. Vishwanathan.R.,Sai Baba, M., Darwin Albert Raj, D.Balsubramanian, Saha,
B., Mathews, C.K., J.Nucl.Mater, 149, 302(1987).8. Venugopal,V., Shukla.N.K., Sundaresh,V., Prasad.R., Roy.K.N., Sood.D.D.,
J. Chem. Thermodynamics, .18, 735(1986).
24
Table - 3.
0
Enthalpy of solution of alloy, /V, ,H (Ni.. cnt,Ten . n c ( S , 29B. 15K), enthalpy—iJal in 0.595 0.405
of solution of synthetic mixture, A _ ,H (0.595Ni+0.405Te,S.298.15K) inb o 1 in
7M HNO^ + 5% H-SO^ and standard molar enthalpy of formation of alloy,
1 (Ni0.595Te0.405'S'298-15K1
SI.No.
1.2.34.5.6.7.8.9.10.
0000000000
Mass ofal 1 oy
g
.04990
.05050
.04961
.05073
.05044
.05044
.05000
.05035
.04980
.04982
J
112.6113.5111.4114.1113.8112.9112.7113.4112.4112.4
0
—Sol m
kJ.mo!
195.437194.659194.484194.800195.406193.860195.220195.067195.482195.404
Mass of syn.mixture
g
0.050860.049740.050330.051180.508480.049840.050190.050560.051440.04981
J
129.9126.7128.3130.5129.8127.4127.9128.9131.4127.2
0
—Sol m
kJ.mol
221.209220.618220.785220.941221.126221.392221.063220.808221.240221.177
C -
kJ.Mol-1
= (194.982 ± 0.335' )
H (0.595 Ni +0.405 Te, S, 298. 15°K )ID
kJ.Mol -1= (221 026 + 0. 157 )
1- (26.044 ± 0.369 )
kJ.Mol
Molar mass of alloy was taken as 86.6104. In each run amount of solvent
(7M HNO + 5% H SO I was kept 500 g.* ± uncertainty is twice the standard
deviation of the mean.
25
Table - 4
°(Ni Te, ,S,298.15°K)values along withm x 1-x
lNi,, COI.Ten . nc, S, 298. 15°K)m 0.595 0.405
Reference Composition
Nl0.476 Te0.524
Nl0.400 Te0.600
( N i o Ten . . , . , S, 298.15°K)
Ni0.333 Te0.667 13 ±
Ni0.565 Te0.435
Ni0.612 Te0.388
Ni0.629 Te0.371 ( 1 9- 2 2 * 2" 0 2 1
Ni0.630 Te0.370
Present work NiQ 5 g g TeQ 4 Q g (26.044 ± 0.582)
1.2.2 STANDARD MOLAR GIBBS FREE ENERGY OF
FORMATION OF Na 2Zr0 3ls)
V.S. Iyer, V.Venugopal, ZiIey Singh, Smruti Mohapatra,
K.N.Roy,R.Prasad and D.D.Sood
Thermochemica1 information on Na 2Zr03 is of importance as it
is formed by the reaction of fission-product zirconium with
coolant sodium during the clad breach of an operating fast
reactor fuel pin. There is a paucity of thermodynainic
information on sodium zirconate. In the present study, the
standard molar Gibbs free energy of formation of Na 2ZrD3(s)
has been obtained by measuring equilibrium pressure of CO2 for
the react ion
Ns 2C0 3(s) + Zr0 2(s) = Na 22r0 3(sl + C0 2(g)
by a static manometric method in the temperature range 878 to
1107K. Analytical grade chemicals were used for the
experiments. X-ray analyses were done on the mixture before
and after experiment for confirming the absence of any new
phase. The C 0 2 pressures were least squares analysed and
can be given by
log (p/kPa) = 7.470 - 7385.2<K/T + 0.038) ...(1)
Using the standard molar Gibbs free energies of formation for
N a 2 C 0 3 ( s ) , Zr0 2(s) and C0 2(g ) from JANAF thermochemica1
Tables^-' and C 0 2 pressure from equation (1), the standard
molar Gibbs free energy of formation of Na 2Zr03(s) was
calculated and can be given by
rL\_fGm(Na2Zr03. S, T) /kJ . mol " l = - 1676.27 + 0.348 (T/K) ± 1 . 1
27
Table - 5 gives a comparison of these values with those
of Maier and W a r h u s C 2 ^ . ft is seen that the two sets of data
are in good agreement. Table - 6 gives the standard molar
enthalpy of formation of Na2ZrO3 values calculated using the
second law and third law method and the available literature
values. It shows reasonably good agreement.
Table - 5.
Dependence of Standard Gibbs free energy of formation ofon temperature.
T/K , S.Tf/W.mol"1
900
1000
Maier and
- 1363
- 1360
Uarhus
.9
. 1
Present
-1363
- 1329
study
.9
.2
Table - 6.
Standard molar enthalpy of formation of Na2Zr03(s) at 298. 15K.
Authors / \H°,,/kJ . mol "̂
Present study (Second law)(Third law >
Bayer et alMaier t* Uarhus'^-'KohliI4]
- 1662.9- 1654.9- 1686.3- 1667.8- 1700.0
Reference;.
1. JANAF Thermocheraical Table NBRDSS, NBS, U.S. Dept. of Commerce,Supplement in J. Phys. Chem. Ref. Data, 4 ,1(1975).
2. Maier, J., Uarhus, U., J. Ch . Thermodynamics ,16,309(1986 1.3. Bayer, R. P. , Bennigton, K. 0. ,Br . n.P.R. , J. Chem. Thermodynamics, 17., 11 <1985).4. Kohli, R. , Thermochemica Act » , 65., 28511983 I.
28
1.2.3. THERMOCHEMISTRY OF Cs 2Cr 207(s,1).
V.Venugopa1, V.S. Iyer, K.N. Roy, Renu Agarwal,
R.Frasad and D.D. Sood.
Ciiesium is a high yield fission product which participates in a
number of interactions with fuel and stainless steel components
of the cladding tube in mixed oxide fuel pins of fast
reactors. The compounds of interest in the reaction of caesium
with S.S. cladding have been suggested to be Cs xCr 04(x=2 to 5)
and their formation depends upon the oxygen and caesium
potentials . Although Cs2Cr207 may not be formed in a
normally operating oxide fuel pin, a study of this oxygen rich
chromate will be of help in understanding the relative
stabilities of caesium- rich chromates. The standard molar
Gibbs free energy of formation and heat capacity data of
(^s2^'r2l-)7(s,l) are not available in the literature. Hence work
was undertaken to determine the free energy of formation of
Cs2^r2'-'7(s''' by e.m.f method and heat capacity by drop
calorimetry using Calvet micro-calorimeter.
•_\ f G m ( Cs2Cr207 , I,T) has been determined in the temperature
range 797 to 87aK in the phase field:
( C s 2 Cr 2O 7(l) + Cs 2Cr0 4(s) *• Cr 20 3ls) ) using the cell
Pt/"Jr-;2Cr207 ( 1 ) + C s 2C r 0 A ( s ) + C r 2 0 3 ( s )/0. 852 rO 2 +0.15CaO/air/Pt
where p(0r.) in air is taken as 21.21 KPa. The detailed
Rxporimenta 1 procedure is given elsewhere. The relation of
r?.ir..f. w i t-h temperature could be represented by
E/mV ± 0.5 = 160 - 0.08104(T/K) - (1)
2 9
Using equation (1) and the reported thermodynamic values for0
Cs2CrO4 and 0 ^ 0 3 , the /_\_f G m (Cs2Cr2C>7. 1,T) was calculated in
the temperature range 797 to 874K and can be given by:
/AfG m<Cs 2Cr 207, 1 , T>/kJ. m o l- 1 ± 10 = -2023 + 0.5268(T/K>
The enthalpy increment measurements on Cs2Cr207(s,1) were
carried out using a high temperature Calvet microcaI orimeter in
the temperature range 335 to 826K. The details of the[4 ]
experimental assembly and procedure are given elsewhere . The
of 99.95 mass percent purity was used for the
experiments. A solid-solid transition has been observed
at (620.5 ± 1.5)K and the melting temperature was found to
be (657 ± 1.0)K. The corresponding enthalpy values
are (15.6 ± O^lkJ.mol" 1 and (17 ± 0. 22 ) kJ . mo I ~ 1.
The enthalpy increment data were fitted in the form of
polynominal and can be given by:
;)J.mol = -6.410x10 +1.939x10 T +7.441x10 T
335 to 820.5K
2 - HT"H298. 1 5 I C s 2 C r 2 O 7 . s l J . m o r 1 = 1 . 3 1 3 K 1 0 6 - 4 . 1 3 7 K 1 0 3 T +3.517T2
620.5 to 650K
3 . H T - " 2 9 8 i 5 ( C s 2 C r 2 0 7 , s l J . r a o r 1 - 1. 218x 10 5 *3. 890x 102T
657 to 826K
The molar heat capacity value obtained in the study by
extrapolation to 298. 15K is 230.3 J.K'/mol"1.
3 0
Using the molar enthalpy increment of Cs2Cr207<l) and the
enthalpy of transition, the molar thermodynamic properties of
Cs2Cr 2O7(l) were calculated and are given in Table -7.
Using the presently obtained C p > m ( Cs 2C ̂ 0 7 , s ) ,
c p , m ( C s 2 C r 2 ° 7 ' ' ) • /_\J98' 1 5Sm f r o m literature , the /A^S^ and
(free energy function) 0 mIT,298.15K) were calculated for
Cs2Cr207(l). The enthalpy of formation of Cs 2Cr207(s) at
298.15K was obtained by summation of the equations:
Cs(s) = Cs( 1 )
C s2 C r2°7 ( i' = C s2 C r2°7 ( s J
2Cs(1)+2Cr(s)+l/2 0 2(g' =
Free energy functions 0°(T,29B.i5K) for Csls),
r " 1Cr(s) and C^tg) were taken from literature. Values
of /_\_f G m (Cs2Cr207, 1,T) were taken from the present study.
Table - 7 gives the thermodynainic functions for CS2C r^O? ' s ' at
700,eOO and 900K.The enthalpy of formation values at 298. 15K
are constant showing no systematic error in the present
investigation.
Table - 7.
Thermodynainic t u n c t ' . o n of 0 3 2 ^ 2 0 7 * I)
K J.K ^mol '
/ l f H ° ( S , 2 9 8 . 1 5 K )
J.K'^mol"1 J.K
'00 589.25WOO 6'il.2900 607.19
216.41238.08254.92
372.8/4403.21432.27
-2099-2101-2100
Re (ere/ices :1. M.G. Adamson, E.A. Aitken, J. Nucl. Hater. 130.3751 1985).2. V.Venugopa1,V.S.Iyer,Renu Agarwal, K.N. Roy, R. Prasarl and D.D. Sood, J,
Nucl. Hater. 11,1047(1987 1.3. JANAF Thermocheroical Tables, J. Phys. Chem. Ref. Data (1975).4. R. Prasad, Renu Agarwal,K.N. Roy, V.S. Iyer,V.Venugopal 3nd D.D. Sood,
Presented at the International Symposium on Thermodynamics of NuclearMaterials, Chicago, Sept. 1988.
31
1 . 2 . 4 . O X I D A T I O N B E H A V I O U R OF UN A N D U 2 N 3
J a y a n t h i K u l k a r n i , G . A . R a m a R a o , V . V e n u g o p a l and
D.D. S o o d
O x i d a t i o n of UN
O x i d a t i o n k i n e t i c s of U N I w i t h and w i t h o u t U 0 2 ) w p r e s t u d i e d at
2 x 1 0 at in. o x y g e n p r e s s u r e as well as in m o i s t u r e w i t h
v a r y i n g p r e s s u r e s r a n g i n g f r o m 0 . 0 3 to 0.12 stm. T h e end
p r o d u c t in all the c a s e s w a s U 3 O 3 . U 0 2 and U 2 N 3 w e r e o b s e r v e d
as i n t e r m e d i a t e s d u r i n g the r e a c t i o n . U h e n U 0 2 c o n t e n t in UN
w a s 12 w e i g h t p e r c e n t , large c o n c e n t r a t i o n of ^2.^3 n a s b e e n
o b s e r v e d as an i n t e r m e d i a t e p h a s e c o m p a r e d to UN c o n t a i n i n g 0.8
'•'eight p e r c e n t U 0 2 . C o n v e r s i o n of UN to U 3 0 g w a s f a s t e r w i t h
s a m p l e c o n t a i n i n g 12 w e i g h t p e r c e n t I'Op. D i f f u s i o n s e e m s to be
t h e m e c h a n i s m of o x i d a t i o n w i t h an a c t i v a t i o n e n e r g y of t h s
o r d e r of 170 kJ.mol . S a m p l e c o n t a i n i n g 0.8 w e i g h t p e r c e n t U O 2
s h o w e d l a r g e r c o n c e n t r a t i o n of U O 9 at i n t e r m e d i a t e s t a g e s .
M e c h a n i s m o b s e r v e d w a s n u c l e a t i o n g r o w t h and 'be a c t i v a t i o n
e n e r g i e s w e r e less than 100 kJ.mol
O x i d a t i o n b e h a v i o u r of U 2 N 3
O x i d a t i o n s t u d i e s on U 2 N 3 w e r e c o n t i n u e d . F o r m a t i o n of UN as
an i n t e r m e d i a t e p r o d u c t w i t h s a m p l e s c o n t a i n i n g U 0 2 as
s e p a r a t e p h a s e h a s b e e n o b s e r v e d on two m e r e s a m p l e s .
N u c l e a t i o n g r o w t h m^ohanisi.i was cbs «= r v <:, j cl •: r i r. g the initial
s t a g e s f o l l o w e d by diffusio;; d u r i n g n or. - i s o t h e r m a l o x i d a t i o n
s t u d i e s . D i f f u s i o n b e c o m e s the only m c c h a . 11 s ni w h e n o x i d a t i o n
w a s c a r r i e d out in i s o t h e r m a l h e a l i n g inodo.
32
1.2.5. VAPOUR PRESSURE OF Pd MEASURED BY KNUDSEN EFFUSION CELL
MASS SPECTROMETRY.
S.G. Kulkarni, C.S. Subbanna, S. Venkiteswaran ,
V. Venugopal and D.D. Sood
* Radiochemistry Division
Vapour pressures of Pd(g) over Pd(s) have been measured in the
temperature range 1237 to 1826K by Knudsen Effusion Cell Mass
Spectrometry <KCMS). A calcia stabilised zirconia Knudsen cell
with < 1 mm. diameter orifice contained in a molybdenum outer
cell was used for the study. An electron energy of
llaJ and IOOJJA current was used for ionising the neutral
gaseous atoms. Temperature of the cell was measured using an
optical pyrometer which was calibrated at the melting
temperatures of Ag, Ni and Pd. Ion intensities measured over
the sample were converted into pressures using the relation:
Pi = k. I
where, Pj = vapour pressure of gaseous ions of atom i.
1̂ = ion current to gaseous ions of atom i.
o' i = ionisation cross section of gaseous atom i.
Hj •- isotopic abundance of atom i.
t[ - multiplier efficiency of ion i.
T = absolute temperature in K.
k = pressure calibration constant.
Values of k were obtained by measuring nickel ion intensities
over Nils) before and after each palladium run . lonisation
cross section and isotopic abundances were taken from standard
Tables. Tj is experimentally determined.
33
The d e t e c t o r c o n s i s t e d of a s e c o n d a r y e l e c t r o n m u l t i p l j p r
and a F a r a d a y c u p c o u p l e d to an e l e c t r o m e t e r /liirn is capal-it/
of m e a s u r i n g c u r r e n t s d o w n to 10 A. O p e r a t i n g f.HM at 10- 1 9g a i n , r e l i a b l e ion i n t e n s i t i e s d o w n to 10 A c~.. a J • 1 •. "j: y fr; :: i i ;,•
be m e a s u r e d .
The a v e r a g e e n t h a l p y of v a p o r i s a t i o n of
N i ( 4 1 8 . 1 2 ± 1 . 5 7 ) k J . m o 1 c o m p a r e s well with l i t e r a t u r e v a l u e
(422.99 ± 2 . 2 3 ) kJ.mol . V a p o u r p r e s s u r e s of P d ( g ) over P d ( s )
can be r e p r e s e n t e d by a least s q u a r e s a n a l y s e d e q u a t i o n :
l o g ( p / k P a ) = (10.91 ± 0.01) - (19069 ± 1 5 9 ) / T < K )
S e c o n d and third law e n t h a l p i e s of v a p o r i s a t i o n are
( 3 7 4 . 2 8 ± 5.42) a n d ( 3 8 1 . 7 1 ± 1.53) k J . m c l " 1 r e s p e c t i v e l y .
In the p r e s e n t study v a p o u r p r e s s u r e of Pd has been m e a s u r e d
over a large t e m p e r a t u r e range of 5 0 O K znd the lowest
t e m p e r a t u r e of m e a s u r e m e n t is 1237K. S u c h a low t e m p e r a t u r e
m e a s u r e m e n t has b e e n m a d e for the f i r s t time.
1.2.6. T H E R M O D Y N A M I C S OF V A P O R I S A T I O N OF CA£ L" ; i.:M MOLYBTATi].
R.P. T a n g r i * , V. V e n u g o p a 1 * *, D.K. P o s f , H. S-uu<: a i am» » «
* M e t a l l u r g y D i v i s i o n , ** fuel C h e m i s t r y D i v i s i o n
and *** A n a l y t i c a l C h e m i s t r y tivis.oi;.
V a p o r i s a t i o n b e h a v i o u r of Cs9iv|o04 ( ! .' ims he^n i ;\:< • .•-; i i •;. « t: e J in
the t e m p e r a t u r e range 1230 tr llii'K' i;y -t i ,.\s r. i ;• n t i o:t
t e c h n i q u e using o x y g e n as c a r r i e r pas. CP--MO",. •?•-•<-po.-s ; •: <;
c o n g r u e n t l y w i t h o u t any d e c o m p o s i t i o n in thi.- jLn-.ve t empp i a t'.:re
r a n g e . T h i s has been c o n f i r m e d by X-ray d i f f r a c t i o n and
c h e m i c a l a n a l y s i s of c o n d e n s a t e sncj boat resi.iua a f t e r
34
carrying out transpiration experiment. Experimental procedure
and data are given elsewhere . As there is no information
available on the existence of polymeric species in the vapour
phase, vapour phase was considered to be monomeric. Vapour
pressures have been least squares analysed and are given by:
log (p/kPa) = (6.37 ± 0.29) -(11452 ± 370>/T(K>
The enthalpy and entropy of vaporisation at the mean
temperature of the present study are (219.26 ± 7.08) kJ.mo I
and (83.56 ± 5.5) J.K .mo I respectively. The second law and0
third law enthalpies of vaporisation (/_SH (vap,298.15K) ai e
(317.3 ± 13.8) and (335.8 ± 2.1)kJ.mo 1"1 . In view of the small
temperature range of the present study, the second law value is
less re 1iabIe.
Reference
1. R.P.Tangri,V.Venugopal,D.K.Bose, and M.Sundaresan, a paperpresented at the International Conference on theThermodynamics of Nuclear materials held at Chicago,U.S.A,September,1988.
Fig 2. TG & DTG CURVES OF Cs2Cr04& Rb2Cr04 IN Ar-7% H2.
A: TG & B: DTG OF Cs2Cr04 (54.9 mg)C: TG & D: DTG OF Rb2Cr04 (60.2 mg)
35
2. CHEMISTRY OF ACT IN IDES
2.1 SOLID STATE CHEMISTRY
2.1.1. SOLID STATE REACTIONS OF (U,Th)02 WITH CARBONATES OF
SODIUM AND POTASSIUM
K.L. Chawla, N.L. Misra and N.C. Jayadevan
Several ternary compounds in the Na-U-0 and K-'J-O systems are
well known. These are a-Na2U04 , C-Na2U04 , Na2U2G7 , NafjU^O^ ana<
Na20.2.5U03 for sodium and K2UO4,K2U207.K2U4013 and K 2 U 7 0 2 2
for p o t a s s i u m , all c o m p o u n d s of U ( V I ) . T h e p r e p a r a t i o n of
and K 2 U / j 0 | 2 , u r a n a t e s in w h i c h s o m e of the
u r a n i u m a t o m s a r e in a lower o x i d a t i o n s t a t e i n d i c a t e d the
p o s s i b i l i t y of r e p l a c i n g t h e s e a t o m s w i t h t h o r i u m a t o m s . T h e
r e s u l t s of the r e a c t i o n s of c a e s i u m c a r b o n a t e and r u b i d i u mt 2 ]
c a r b o n a t e w i t h ( U Q g T h Q i ' O 2 w e r e r e p o r t e d e a r l i e r . As a
c o n t i n u a t i o n of this s t u d y N a 2 C 0 3 and K 2 C 0 3 w e r e h e a t e d w i t h
e q u i m o l a r q u a n t i t i e s of ( U Q _ y T h g . 3 ) 0 2 s o l i d s o l u t i o n s . T h e
p r o d u c t s f o r m e d at 9 0 0 ° C w e r e e x a m i n e d by m e a n s of their X~ray
p o w d e r d i f f r a c t i o n . T h e d a t a a r e p r e s e n t e d in T a b l e - 8.
N a ? C 0 3 g a v e a m i x t u r e of <x-Na 2U04 and a c u b i c f l u o r i t e0
(U,Th)0 2 phase having a = 5.502A. The starting (UQ.7ThQ.3>0 20
has an a value of 5.509 A . On the basis of Vegard's law the
percentage of thorium in the fluorite phase works out to be 88
percent. The reaction with K 2C03 on the other hand gave a
mixture of K 2U 207 and ThO 2. The (UQ,7Thg,3)0 2 when heated in
air leads to the formation of a mixture of U 3 0 9 and a cubic0
( U , T h ) 0 2 p h a s e w i t h a = 5.47 8A by o x i d a t i o n . In air u r a n i u m in
' '-'o. 7 f ^ 0 . 3 "-!2 r e a c t s p r e f e r e n t i a l l y w i t h the c a r b o n a t e s ,
leaving the t h o r i u m to r e m a i n as T h O 2 or. ( U , T h ) 0 2 w i t h
d e c r e a s e d u r a n i u m c o n t e n t . No r e a c t i o n took p l a c e w h e n the
h e a t i n g w a s d o n e in an inert a t m o s p h e r e . W h e n m i x t u r e s of U 3 O Q ,
36
and t h e c a r b o n a t e s a r e h e a t e d in a i r , t h e p r o d u c t s w e r e
t h e u r a n a t e s and
References.
1. K.L.Chawla, N.L.Misra and N.C.Jayadevan, J . Nucl .Mater. , 154.181(1988).2. K.L. Chawla, N.L.Misra and N.C.Jayadevan, Proc. Radiochera.and Radiat ion
Chem. Symposium, Bombay(19881, PaperNo.CT-27.
(U,Th)0 2 l i n e s
a = 5.582 A
Table - 8
X-ray Diffraction Data
Na2C03 +900 °C
d(A> I
4.923.230*
2.8482.793K
2.4662.2102.0171.970K
1.6831.647
M02**
"°
80100
10040101040505040
a-Na2U04
900 °Cd(A)
4.95
2.857
2.4712.2182.019
1.649
i/io
100
83
161227
21
K2C03
900°Cd(A)
6.563.4303.2803.230*2.8392.801*2.1802.0131.970*1.9261.7141.688*
i/io
1515501001045102510101565
900d(A)
4.163.4083.164*2.7412.6371.942*1.6531.581
*
°Ci/io
10101004010403515
* <U,Th)02 l i nes » (U ,Th )0 2 l i nes
a = 5.598 A a = 5.478 A
a = 5.509 A
37
2.1.2. PHASE STUDIES IN THE Na-U-0 SYSTEM
A.K. Chadha and N.C. Jayadevan
Knowledge of the formation of different phases in the Na-U-0
system are important from the point of fuel coolant
interaction in fast reactors. Following the observation that
the addition of small amounts of alkaline earth ions into the
K-U-0 system leads to the formation of new cublic solid phases,2+ 2 +
a study of the Na-U-0 system in which Sr ,Ba
or Ca ions are added was taken up as a continuation.
(a) Na-U-Ba-0 system.
Mixtures of NaN03,U02 and Ba(N03)£ in different molar
proportions were heated in the temperature range of 900-1050°C
and the reaction products examined by means of their X-ray
powder diffraction patterns. The compositions studied and the
phases identified are shown in Table - 9. in all the
experiments either the amount of Na(N03> or Ba(N03>2 was varied
maintaining the concentration of UO2 between 1.0 and 1.1M.
When the amount of NaN03 was varied from 1.80 to 3.50 keeping
Da(N03>2 constant at 0.1M, the products gave X-ray lines of a
new cubic phase (Phase 1) alongwith those of either Ua.2<J0^ or
Na2^2(-'7- This phase was obtained as a pure phase with the
composition of NaN0 3 :U02:Ba<NO3>2 as 3.25:1.1:0.25 . Continued
addition of Ba(N03>2 led to the formation of another phase
(Phase M ) within the range of 1.1M to 3.5M. This phase was
isolated as a pure phase for the concentration range of
Ba(N0 3)2 between 1.40M and 1.70M. Yet another phase
designated as Phase 111 was obtained for Ba(N03>2 .4.0M or
above. All the three phases (I, II & 111) isolated in this
study were found to be new phases unknown in the Na-U-0 or
Ba-U-0 systems.
38
The X-ray powder p a t t e r n s of phase-1 and phase-I1 have beenO 0
indexed on cubic s y s t e m s with 'a' values of B.401A and 15.00 A
r e s p e c t i v e l y . The indexed data are given in Tables 10 and 11.
(b) N a - U - C a - 0 System.
The results of e x p e r i m e n t s similar to that of the M a - U - B a - Q
system c o n d u c t e d by s u b s t i t u t i n g CaCO.g in place of
B a l N O ^ ) ? are shown in T a b l e -12 along with the solid phases
identified as reaction p r o d u c t s . For most of the c o m p o s i t i o n s ,
the products w e r e identified to be m i x t u r e s of Na2UC>4 and
Table - 9.
Phases identified in Na-Ba-U-0 System.
Composition of Starting Mixture Heating Conditions Phases identified
NaN0,3 UO2 Ba(N03)2 Temp Time from X-ray pattern
(°CI (hrsl
1223.3.
3."i.3.3.
3.3.3.3.3.
3.3.
8000500030
' J
25525030
3030303030
3030
11111
11.t.1.1.
1.1.1.1.1.
1.1.
10101010
1010101010
1010
00000
00011
1.1.2.3.3.
4.4.
. 1
. 1
. 111
1255751043
6069500050
0050
1050870880930980
950950950950950
950950950950950
950950
34833
33332
22222
22
B-Na2U04
oc-NanU(
PhasePhase
PhasePhasePhasePhasePhase 1
Phase 1Phase 1Phase 1Phase 1Phase 1
Phase 1Phase i
+
* Phase 1
+ Phase 1
+ Phase I
+ Na?U?07
+ J3-Na2UOA
Add i tona 1 1ines
only1 +I1
111!!
I 1I I
Add i tona 1 1ines
+ Phase 1 1 I
+ Phase III
• Phase 111
39
Table - 10
Indexed Pattern of Phase I in the Na-Ba-U-0 System
Corr.26 Observed Calculated H (hkl)Observeds inJ0
Calculatedsin5 9
22352210014
1116391133
60128225
155
2288
5
Body Centred Cubic :
15.0121.2626.0130. 1433.74
37. 1440.2443. 1045.8948.54
53.4855.8360.3862.6364.63
66.8368.8870.9375.0378.98
BO. 93
z : a =
.01706
.03403
.05064
.06760
.08422
.10142
.11833
.13495
.15198
.16895
.20245
.21917
.25288
.27013
.28577
.30327
.31984
.33664
.37084
.4044
.4218
0
8.401 A
0168403368050520673008420
1010411788134701515616840
2020821892252602694428628
3031231996336803704840416
246810
1214161820
2426303234
36384.4448
.4210 50
(110)(2001(211)(220)(310)
(222)(321)(400)(411!;((330)(420)
(422)(510;(431)(521!(4401(530);(4331
(600);(442)(6111 ; (5321(620)(622)(444)
(7101;(543)
40
Table - 11
Indexed Pattern of Phase II in the Na-Ba-U-0 System
Corr.29 Observedsin19
Calculatedsina0
( h k l >
17
22
100
14
36
7
46
6
17
6
17
6
17.82
26.70
29. 17
34.32
41.695
45.67
51.67
55. 12
60.47
63.57
68.57
76.22
0.02399
0.05292
0.06341
0.08705
0.12665
0.15061
0.18991
0.21407
0.25356
0.27745
0.31732
0.38090
0.02114
0.05284
0.063408
0.08720
0.12682
0.15060
0.19022
0.21400
0.25363
0.27741
0.31704
0.38050
(220)
(420)
(422)
(5221;(441)
(444)
(722);(544)
(660);(822)
{ 900) ; (841)
(844)
(854) ; (10 , ' ' , 1)
(10,4,2)
(12,2,1)(982);(876)(10,7,0)
Cubic a = 15.00 A
41
Table - 12
Compos
NaN03
1
1
1.
1.
1.
1.
2
2.
3.
3.
.46
.59
.694
,75
.765
77
7
2
5
ition of
mixture
U 0 2
1
1
1
;_
1
0.80
1
1
1
1
Phases
starting
CaC03
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
, 11
.1
7
11
19
3
11
11
1
1
ident i f ied
Heating
TempCO
930
930
930
800
930
920
930
930
950
900
in Na-Ca-U-0 System
Condit ions
Time(hrs)
2.
2
2
34
2
3
2.
3
3
3
5 Na2U20? +
Na 2U 2n7 +
Na 2U 20 7 •
I a-Na2U0/(
Na 2U 20 7 4
new phase
5 Na 2U 2n7 +
Na2U2°7 +
N a 2 U 2 0 7 ••
Phases
fi-Na2U0,
new phase
8-N32U0/, + new phase
• new phase
B-NanUO/j + new phase
6-Na2U04 + new phase
fl-Na2U04
6-Na2U04
8-Na2L/0,(, + new phc.se
H o w e v e r s o m e a d d i t i o n a l l i n e s w e r e o b s e r v e d f o r
1. 50M<NaN0,3<2. 5M with maximum intensities around 1.75M. These
lines belonged to a new phase in the Na-Ca-U-0 system which
could be isolated as a pure compound by reducing the
concentration of UO2 and increasing that of CaC03 . The X-ray
powder pattern could be indexed on an orthorhombic system
with cell parameters a = 5.76A,b = 5.91A and c = 8.25A.
These parameters are very close to those of NaU03
(i.e.a = 5.776A,b = 5.91&,t* c = 8.203&) where all the U atoms
are in oxidation state +5 . The compound prepared in this
study contains only U(VI). Hence the addition of about 0.3M of
C a + 2 ions causes the stabilization of the new structure for
U(V1). The X-ray data indexed in Table -13.
42
Table - 13
X-ray data for Na-U-Ca-0 SystemNaN03: U02 : CaC03
1.77 : 0.80 : 0.314
I/I0
2494
11132910026813192411481024481537351124
26
15.21.
26.26.30.30.31.32.34.37.36.*.}.43.46.48.49.50.53.55.56.63.
,09,54
29692440094434340454845684340489048465
sin2 9obseived
0.017260.03492
0.051720.53280.068040.069360.071820.078020.87150.102470.106210.120020.139360.156080.170920.174220.178870.205330.213500,226510.2741
sin'Gcalculated
000000000,0.0.0.0.0.
0.0.0.0.0.0.0.
.01700
.03460
.03480
.05164
.05254
.0680
.06954
.0716
.7794,0858. 1029,10624,12021396
170917424179562055421446227162720
(hkl)
(100)(002)(110)(012)(102)(020)(112)(200)(0031(120)(113)(202)(212)(220)
(130)(222)(131)(132)(1241(214)(040)
rthorhombic 5.762 A , b 5.913 A and 8.284 A
43
c) N a - U - S r - 0 System.
For the studies in this system UD2iNaN03 and Sr(N C 3 > 2 were
heated together. By taking 1. Oh U 0 2 and 0.2-0.3'M S r ( N 0 3 ) 2
and increasing the amounts of NaNOg from 1 to 4.0M, a new
phase was noticed at a concentration of 3.30M of NaNCl3. The
X-ray lines of this new phase could he i n"K?v. ed on a cubic cell
of a = 8.327 A*. The indexed pattern given iji Table -14
that this phase is present along with some other pha
value of 8.327 A for the new phase i •; in ag r rjcmuii t
smal ler ionic radius of C a ^ + compared to that of
which case the cubic cell has a dimension of
Addition of more amounts of Sr(N03)7 to the above •
gave Sr3U0g phase.
Table - 14
X-ray data for Na-U-Sr-0 System
NaN0 3 :U02 :Sr{N03!?
3.20 :1.10 : 0.3
S 3
W i
Ba
5.
th
2 +
'iOi
The
the
i n
A.
1/ 26 Corr.19Observed
H Sin- 3
C a l c u l i i •-<}
1430
40
510
4
5
5
197
518
17
15
12
28
67
2
3575
100
13
2511
14
13
48
10
13
4543
38
306
20
15
18
6
14,26.
30.
33.
37.38.
40.
42.43.
45.
47.
48.63.
54.
55.56.
62.
67.71.
75.
,90.20
,25
85
55
80
52550
30
90
5570
60
2010
15
90
05
45
20
1526
30
33
37
36
40
42,
43,
•'(6.
4 7.
48.
53.54.
55.
56.63.
6 7.
71.
75.
.00
.30
.35
.95
.65
.90
.535
.60
.40,00
80
70
30
2025
00
15
55
30
0.0W0370.051757
O.O6:<5220.85237
0. 1C4J2
0.11086
0.119967
0. 13H/5
0.136" 1
0. 15;:67
0 1631 ?
0.J70655
C.2O2P30.2082?
0.21A64
0.222:-i50.273G0
0.30564
0.3117P
0.373121
25
8
10
14
16
16
19
20
ro32
40
00
0
0
0
0.
0.
0.
0.
0.r\\J -
0.
0.
.0171305
.05139
.068522
.0865
.1199
. 1370
. 15417
16274
171305
2K13
222632740
3426
Cubic: a = 8.327 K
44
2.1.3.THERMOCHEMICAL STUDIES ON Cs-Cr-0 AND Rb-Cr-0 SYSTEMS.
S.Sampath, S.K. Sali, N.K. Kulkarni and N.C. Jayadevan.
For the mixed uraniurn-p1utoniurn oxide fuels, chemical
interaction between fission products and stainless steol
cladding is recognized to be the result of the oxidation of
chromium. Caesium is a reactive fission product which attacks
the cladding. Thermochemica1 studies on the Cs-Cr-0 and the
Rb-Cr-0 systems were taken up to understand the basic chemistry
of these compounds under different conditions. The compounds
known in these systems are Cs^r^l • Cs2CrO4, Cs3CrO4 , Cs4CrO4
and C S C ^ O Q for caesium and Rb2Cr20y ,Rb2CrO4 and RbCr3Q3 for
rubid ium' * •*. The techniques used in this study are
thermogravimetry(TG) and X-ray diffraction.
The monochromates, M2CrO4 and the dichromates,
(M = Cs or Rb) were heated in a thermoana1yzer in a flowing
stream of argon-7% hydrogen gas upto 1200°C. The
thermogravimetric (TG) and the differential thermogravimetric
(DTG) curves recorded are shown in Fig.2. The weight losses
recorded are found to be 4% upto 65O°C, 67.5% upto 1000°C and
80% upto 1200°C in the case of Cs 2Cr04 . The final product
obtained was identified to be only Cr203 . The weight loss
also corresponds to the complete loss of caesium. The first
intermediate reaction product formed at 650°C has a composition
Cs2CrO3 on the basis of the 4% weight loss. This product did
not give any X-ray diffraction pattern. However, this
hygroscopic product was converted to Cs2CrO/4 on storing. The
other intermediate product formed at 1000°C with a weight loss
of 67.5% gave the XRD pattern shown in Table - 15.
These lines do not correspond to that of Cr203 or any other
known compounds in the Cs-Cr-0 system. Oxidation of this
product by heating in air showed an exothermic reaction between
45
4 0 0 a n d 5 0 0 ° C w i t h a w e i g h t g a i n of 3% r e s u l t i n g in . i.,i.:i\>ie
of C s 2 C r O 7 a n d C r 2 0 3 , t h e r e b y i n d i c a t i n g , U i a t i .i the;
i n t e r m e d i a t e o n l y p a r t of t h o c a e s i u m is l o s t .
T h e r e s u l t s f r o m t h e T G a n a l y s i s oi' R b o C r O / t i •• n u i t e a i ;JI i . " •
t h a t of C s 2 C r O ^ d e s c r i b e d e a r l i e r . Th<? fj.-;,t v .-.= i >; 1. r. I i..: r
c o r r e s p o n d s t o t h e f o r m a t i o n of R b 2 C r O , 3 , -.he in':i.-iiY: ., i;»• i;
f o r m e d a t 1 1 5 0 ° C i s a c o m p o u n d o f u n k n o w n c o m ] j i i iu;i a;i-i '..li'
f i n a l p r o d u c t a b o v e 1 2 0 0 ° C is i d e n t i f i e d a s C.'/H-j •,/i * N ; ;:;:•
l o s s o f a l l t h e r u b i d i u m ( w e i g h t l o s s 7 4 % ) a s in .'..;.e c^.;.'
of
T h e i n t e r m e d i a t e g a i n e d 3 . 5 % w e i g h t o n o x i d a t i o n in .? i i •:i\;,
t h e f o r m a t i o n of a m i x t u r e of R b 2 C r 2 0 7 a n d C ^ U ^ . Tt• r? .-., y ? c n
c o n t e n t w a s a n a l y z e d to g i v e v a l u e s of 2 2 . 3 6 arid ;-.:.. G C :
r e s p e c t i v e l y f o r t h e c a e s i u m a n d r u b i d i u m i n t e r m e d i a t e s . Th;-se
r e s u l t s p o i n t t o a c o m p o s i t i o n fijjCrO^ f o r t h e ;r-i L •; -i-'.st. i h•' ••;;
w i t h x * 0 . 4 . T h e X - r a y p o w d e r p a t t e r n of t h e i n t e r m e d i a t e s a r ^
g i v e n in T a b l e - 1 5 . In t h e K - C r - 0 s y .= t%;nr t .JO n o n -
s t o i c h i o m e t r ic o x i d e s K x C r 0 2 w i t h x v a l u e s co-. r-Ti-.poi-i'iin;; >* <_•
0.7 < x < 0.77 and 0.5 < x < 0.6 have been r e p o r t e d ^ ' Icrdin;;
s u p p o r t to t h e a b o v e c o m p o s i t i o n . T h e r e s u l t s of thn rfiriij-rlic1
a n d o x i d a t i o n s t u d i e s a r e s u m m a r i s e d in Table? - i ̂.
Table - 15
X-ray Powder Diffraction Data on CsxCr0"2 3tv' ^b xC;O,
C s x C r 0 2 Rb.-C-.O,,
Intensity d Intensity c
m 3.479 m 3. ,93
m 2.549 m J.S'^.1
m 2.270 v 2.392in 2.29 w 2.14)m 2.085 m 2r.:biw 1.563
46
StartingMaterial
Cs2Cr04
Cs2Cr04
CS2Cr04
(x * 0.4)
Rb2Cr04
Rb2Cr04
Rb2Cr04
IK** 0.4)
Atra.
"2
H2
H2
Air
H2
"2
H2
Air
Table - 16
Thermal Behaviour of Cs2Cr04
Temp.°C
650
800
1200
500
675
900
1200
500
Overal1composi tionof sol idproducts
C S 2Cr0 3
(x "0 0.4)
Cr 20 3
Cs2Cr207+ Cr 20 3
Rb 2Cr0 3
(x % 0.4)
Cr 20 3
+ Cr 20 3
and Rb2Cr04
Wt loss/gainobserved
- 4
- 67.5
- 80
+ 3
- 6
* 60
- 74
+ 3.5
Ut loss/gaincalculated
(%l
- 4.2
- 66.7
- 80
+ 3.2
- 5.6
* 61
- 73.5
+ 3.5
TG of Cs2Cr207 in Ar-736 H2 showed that weight loss of around
was observed above 500°C followed by rapid volatilisation.
207 behaved similarly. XRD of reduction products showed
presence of Cs2Cr04 and 0^03 and Rb2CrO4 and Cr2C>3 • No new
phases could be identified. Heating at higher temperatures gave
only
T.M.Bumann and C.E.Johnson,J.Nucl.Mater.
References
1. T.B.Lindemer,100,178(1981).
2. C. Delmas, M. Dovalette, C. Fouassier and P. HagenmulIer,Mater.Res. Bulletin 10,393(1975).
47
2.2 SOLUTION CHEMISTRY
2.2.1. STUDIES ON SOLVENT EXTRACTION OF Pu(IV) BY D2EHPA
D.G. Phal, S. Kannan, V.V. Ramakrishna and S.K. Patil
A. The nature of Pu(IV) complex extracted by D2EHPA from
sulphuric-nitric acid solutions.
Previous studies have shown^•^'that the composition of the
Pu(IV) species extracted by D2EHPA in toluene from sulphuric
and nitric acids was Pu'r^Yg and Pu(N03)2H2Y^ respectively.
In the presence of controlled amounts of nitrate ion the
species Pu(N03)H2Y5 was identified in the extraction of
Pu(IV) from sulphuric acid , using different diluents viz.
toluene, dodecane and chloroform.
With a view to find out the maximum number of Y groupings in
PUH2Y5 that are replaceable by nitrate or TTA anions,
experiments on the extraction of Pu(lV) from sulphuric acid
were carried out (i) in presence of higher concentration of
nitrate ions (ii) by the addition of thenoyItrif1uoro acetone
(HTTA) to the organic phase, and (iii) by completely replacing
sulphuric acid with nitric acid.
The D values of Put IV) obtained using 1M sulphuric acid and
higher nitrate concentrations are given in Table -17. It is
seen that the values of (D.F/DO - 1)/[NO§] (where F is the
aqueous nitrate complex ing factor of Put IV)) remained almost
constant with [NO3] with dodecane as the diluent and increase
linearly using toluene and chloroform as the diluents. This
suggests that predominantly, only mononitrate species is
extracted in dodecane whereas the dinitrate species are also
48
involved in the other two diluents. The data were also
obtained on the extraction of Put IV) as a function of the
D2EHPA from nitric acid concentrations of 1,3 and 6M. They
suggested the dominance of the mononitrate species at 1 M HNO3
and that of the dinitrate species at high HNO3 concentration
when dodecane was the diluent. In case of toluene and
chloroform diluents dominant presence of the dinitrato species
was observed under all the conditions studied. It is
significant to note that in no case, the extraction of Put IV)
species with more than two nitrate ions is indicated.
B. Synsrgism in the extraction of Put IV) by mixtures of D2EHPA
and HTTA.
It was felt that if the Y groupings in PuY2(HY2'2 a r e
replaceable by nitrate ions, such a substitution may also be
possible with anion such as TTA~. The extraction of Put IV)
from aqueous sulphuric acid by mixtures of D2EHPA and HTTA was
studied. The data obtained on the variation of sulphuric acid
concentration with a constant concentration of D2EPHA, HTTA and
a mixture of them using the diluents dodecane, toluene and
chloroform revealed that in each case, appreciable synergism
was observed in the Put IV) extraction with the mixture. If the
rynergism is due to the replacement of the Y by the TTA
groupings, according to
+ HTTA > PuH 2Y 5(TTA) + 1/2 H 2 Y 2 - (1)
and PuH 2Y 6 + 2HTTA — > P u H 2 Y 4 ( T T A ) 2 + H 2 Y 2 - (2)
it can be shown that the plot of (D/DQ - 1)/[HTTA] Vs. CHTTA]
where D and D Q are the distribution ratios of Put IV) obtained
with a fixed concentration of H 2 Y 2 and aqueous medium in the
presence and absence of varying concentration of HTTA,
49
respectively, would be a straight line with positive values for
both the intercept and the slope . Data obtained with dodecane
and toluene as diluents are given in Table - 18.
The plots of (D/D o - 1)/[HTTA3 Vs CHTTA3) for all the three
diluents studied were found to be straight lines. Equilibrium
constants for equations (1) and (2) were calculated and the
values obtained are summarised in Table - 19. The fact that
only two Y groupings in P u ^ Y g are replaceable by either
N0§ or TTA" anions suggests that the formula PuY 2<HY2>2 i s
preferred over PUY42HY for the species Put-^Yg extracted from
aqueous sulphuric acid.
C. Antagonistic extraction of Put IV) by mixtures of D2EHPA and
TQPO from sulphuric acid.
It was shown earlier^-' that Pu(IV) species extracted from
H2SO4 medium by D2EHPA taken in three diluents dodecane,
toluene and chloroform was PuH2Yg . Probable structural
formulae for this composition are:
(i) PuY 4.2HY or (ii) PuY 2(HY 2)2
Synergism in the extraction of Put IV) by D2EHPA in the presence
of TOPO is expected due to the formation of species like
(i) PuY 4.HY.T0P0 or tii) PuY 2<HY 2>2•TOPO
.he data obtained on the variation of the distribution ratio
of Put IV) under different conditions are given in Table - 20.
The observed antagonism in dodecane and toluene is obviously
due to an interaction between the extractants. <j-donors like
alcohols monomerize D2EHPA and hence a similar role is expected
from TOPO. The antagonism is not observed in chloroform and
this is probably due to its strong interaction with TOPO by
H-bonding. The reasons for the lack of synergism in these
systems are being investigated.
50
References.
1. D.G.Phal, S.Kannan and V.V.Ramakrishna, DAE Radiochem. Radiation Chem.Symposium,Bombay!1988), paper CT- 18.
2. Ibid. Paper CT- 203. Ibid Paper CT- 19
Table -17
Extraction of Pu(IV) by D2EHPA(HY) from 1M sulphuric acid and nitrate ionconcentration.
CNO3] D of Pu(IV) with (D.F/DO-1)+ [NO3] withM Dodecane Toluene Chloroform
[HY] CHY] CHY] F Dodecane Toluene Chloroform= 0.4 F = 0.2 F = 0.2 F xlO xlO xlO
0
0.
0.
0.
0.
0.
1
2
3
4
5
0.
15
26
34
43
52
0720
. 1
.2
.4
. 1
.5
0.0121
2.55
5.00
7.14
9.43
11.5
0.00417
0.0879
0.205
0.340
0.438
0.543
1.
1.
1.
1.
1.
1.
00
33
56
77
87
95
2.
2.
2.
2.
2.
74
80
78
76
81
2.
3.
3.
3.
3.
79
22
47
63
70
2.
3.
4.
4.
5.
75
85
86
98
15
51
Table -18
Variation of the distribution ratio D of Pu(IV) with concentration of HTTAAqueous medium - 0.224(1 sulphuric acid.Organic medium - D2EHPA + HTTA in various diluents.
CHY)=O.
[HTTA]M X
0
2
4
6
8
10
12
16
20
005F in
D
0.0723
0.276
0.746
1.39
2.07
3.17
dodecane [HY]
(D/Do-1)
IHTTA]xlO
-
1.41
2.33
3.05
3.45
4.28
=0
0
0.
0.
0.
1.
2.
.04F in
D
.0355
,157
486
869
53
37
toluene
(D/Do-1)
[HTTA]xlO
-
-
0.856
-
1.59
-
1.96
2.63
3.29
[HY]=0.05F
D
-4
0.0116
0.265
0.902
1.95
3.45
5.40
in chloroform
(D/Do-1)
CHTTA1xlO
-
1.09
1.92
2.79
3.70
4.64
52
Table -19
Equilibrium constant data determined for different
encountered in the Pu(IV) extraction by D2EHPA+HTTA.
Aqueous medium - Sulphuric acid.
equiibria
Equi1ibriumlog equilibrium constant
dode- tolu- chloro-cane ene fora
Pu 7.99 5.18 4.29, , • ""z-z, > —>PuY2(HY2)2l .+ 4(aq) z Mo l c ^ Mo)
PuY2(HY2))2(o)+ "TTA(o) —>PuY(TTA)(HY2)2 + 0.5H2Y2(o) 2.57 2.55 2.20
PuY 2(HY 2) 2 ( o J + 2HTTA(Q) ->Pu(HY2)2(TTA)2{•, H 2Y 2 ( o ) 4.95 5.48 5.06
+ 4Pu, ,+2.5H2Y2,+1HTTAI . —>PuY(TTA)
(aq) z ^(o) (o) '(aq)
Pu+4( a q )
+ 2 H 2 Y 2 ( o ) + 2HTTA (o)->Pu(TTA.2(HY2.2
10.56 7.73 6.49
12.94 10.66 9.35
53
Table -20
Variation of the distribution ratio D of Put IV!Aqueous phase : 0.224 to 1.02 M Sulphuric acidOrganic phase : D2EHPA + TOPO in various diluents.
CH2S04]
Di iuent
0.2240.4230.6220.8211.02
Diluent
0.2240.4230.6220.8211.020
Oi1uent
0.2240.4230.6220.8211 J2
DA
- Dodecane, A
2.310.2420.05980.02110.00931
- Toluene, A
2.930.2940.06610.02230.00998
- Chloroform, A
4.050.4110.09110.03000.0145
- ID2EHPAJ
0.07100.05790.05720.07060.0597
- [D2EHPA]
0.2080.1630.1450.1530.160
- CD2EHPAJ
0.1010.08690.06890.05800.0563
(DA+DB)
= 0.02F; B - 1
2.380.3000.1170.09170.0690
= 0.2F; B -
3.140.4570.2110.1750.170
D(A+B)
[TOPO] = 0.02M
0.6160.1450.08150.05660.0507
[TOPO] = 0.1M
0.9960.2780.1500.1150.0999
= 0.4F; B-IT0P01 = 0. 1M
4. 150.4980.1600.08800.0708
3.660.4930. 1790.09570.0648
D(A+B>c -
<DA+DB)
0.260.480.700.620.73
0.320.610.710.660.59
0.880.991.121.090.92
2.2.2. SOME STUDIES ON THE EXTRACTION BEHAVIOUR OF
ACTINIDES BY LONG-CHAIN SECONDARY AMINES.
A.G. Godbole, Rajendra Swarup and S.K. Patil.
Extraction of actinides by long chain secondary amines is
considerably weaker as compared to the tertiary and quarternary
amines ^1 , 2 ] . However, it has two major advantages:
(i) a high decontamination factor for the more common
fission products and
(ii) an easy back-extraction.
A programme on the extraction of actinides by Jong-chain
secondary amines has been initiated with a view to explore the
possibility of using it for the recovery of uranium and
plutonium from the scrap obtained during fuel fabrication,
their separation from each other and from other impurities
if any. In the present work, experiments were carried
out on the extraction of Pu(IV) and U(V1) by Amberlite
LA- 1 ( N -Dodecany 1 trialkyl- rnethy 1 ami ne ) in benzene from aqueous
nitric acid and the results obtained are reported.
Put IV) was prepared by extracting Pu into TTA from iM HNO3 and
back extracting into 8M HNO3 . Sodium nitrite was used as the
holding oxidant. Amine was preequiIibra ted with corresponding
nitric acid concentration. An equilibration time of 30 minutes
was chosen. 233|j w a s u s e d as tracer for the experiments with
U ( V [ ) .
P r e l i m i n a r y e x p e r i m e n t s s h o w e d t h a t the d i s t r i b u t i o n r a t i o s (D>
o b t a i n e d by t a k i n g the met a l ion i n i t i a l l y in e i t h e r
p h a s e w e r e s a m e s h o w i n g t h e r e b y the r e v e r s i b i l i t y of t h e
e x t r a c t i o n s y s t e m . D i s t r i b u t i o n r a t i o d a t a of P u ( l V ) a n d U < V I )
a s a f u n c t i o n of n i t r i c a c i d c o n c e n t r a t i o n a r e g i v e n in
55
Table -21. It is seen from the table that D values for Put IV)
increase initially with a maximum around *7M HNO3 . In the
case of U(V1) the D values obtained were almost constant with
the increase in HNO3 concentration. Distribution data for
Pu(IV) and U(V I ) were also obtained at higher temperatures
which indicated decrease in D of PuilV) with increase in
temperature. However, there was no sifnificant change in D of
U(V I ) at higher temperatures.
Attempts were made to back-extract Pu from the amine phase by
using very dilute nitric acid. It was observed that the
stripping was not complete. However, quantitative stripping
was obtained when ammonium oxalate was used as the stripping
agent. From these results, it is indicated that separation
betwen Pu and U is more favourable around 7M ;iitric acid.
However, more work is required to substantiate this.
References.
1. P.R. Danesi, F. Orlandini, G. Scibona, RT/CH I 65. 21(1965).2. Boyd Weaver and D.E. Horner, J. Chem. Eng. Data 5_ ,266(1960)
56
Table - 21
Variation of Distribution Ratio of Pu(lV) and U(VI! with nitric acidconcentration.
Organic phase LA-IX in benzene
H N 0 3
(MlDistribution Ratio !P)
Pu( I V) I" (VI -
6789
10
5.58 .9
14.214.711.0*
9. 4««
16.75-
9 .26.4
---
0 . 6 1o.r,3»0.52**0.7V.0. 740 .670 . 7 00 .64
* At 40 °C** At 50°C
2.2.3. POLVFN1' F'.'. TRACT I ON S T U D l t S Oi- '("l
F'l. ("1) BY Di-2 ETHYLHEXYL PHOSPHORIC ACID iO
/-NO
r,. V . Chet ty , P . M. Mapara, R.Swarup, V . V . Ramakr i shna aiui
S.K.Pati1
1}_1 ion by D2EHPA
The solvent extraction studies of hexavalent plutonium and
uranium ions were carried out rising the extractant
D 2 E H P A ( H 2 Y 2 ) from 0.1M and 0.2M aqueous sulphuric acid. The
d i s t r i b u t i o n ratio (D) data obtained as a function of [H2Y2;)
and C H + ] were plotted on a log-log plot which gave slopes of
+ 2 and - 2, respectiveIy and the slope values were independent
of diluents used viz. dodecane, toluene and chloroform. From
57
the data (Table 22) it may be inferred that the extraction
mechanism appears to be similar to that reported earlier for
HCIO4 medium.
Extraction by mixture of H2Y2 and TOPU
The extraction studies of both Pu(Vl) and U ( V I ) were carried
out from 0.2M H2SO4 using mixtures of H2Y2 and TOPO at
constant TOPO. The D values were obtained as a function of
[H2SO4] by keeping the concentrations of [H2Y2] and [TOPO]
constant (Tables 23 and 2 4 ) . The log-log plots of /\_D Vs. [H + ]
gave straight lines with slopes close to -2. The log-log plots
of /_\D Vs. CH 2V2] a n d £AP V s- CTOPO] (Tabl es 25 and 26) gave
straight lines with slopes of 1.8 and 0.6 respectively. The
interaction between H2Y2 anc' TOPO is probably responsible for
the lower slopes than the expected values of 2 and 1
respectively. From the data it may be concluded that
the species responsible for synergism probably is
M0 2[H<D2EHP>2]2 •TOPO where M stands for plutonium or uranium.
Studies on absorption spectra
The absorption spectral work was carried out for U(V1) with a
view to infer the nature of species extracted into the organic
ph.de. The absorption spectra of U(V1) extracted into H2V2 in
different diluents from different acids were recorded in the
range of 350-500 nm. The extraction was carried out from two
different concentrations of HCIO4 , HNO3 or HC1. In case of
toluene as the di1uent.sharp peaks were observed for the U(VI)
species extracted from higher acidities than those obtained
from lower acidities suggesting the species extracted in these
two cases are probably different. However, the spectra of
U(VI) solutions using dodecane as diluent extracted from HC1
medium and chloroform as diluent extracted from HNO3 were
independent of acid concentrations.
58
Table -22
Variation of distribution ratios of Pu(VI) and U (V1 ) with C l ^ ^ in differentdiluents.
Aq. phase = 0.1M H2SO4 .
(D2EHPA) D ValuesC _
Pu(VI) U(V1)
1. Dodecane
0.0010.0020.0030.0040.005
II. Toluene
0.0040.0080.0100.0120.0160.020
I I!.Chioroform
0.0100.0200.0300.0400.050
0.01780.07050. 1570.2870.459
0. 1440.2120.2710.5530.905
0.06780.2640.5881.011.66
0.04630.2010.4630.8501.46
0.04220. 171
0.3710.6831.01
0. 1410.5631.252.203.39
59
Variation ofOrganic Phase
Diluent :
Table - 23
D of0.020 F0.025 M TOPO0.020 F H2Y2
Toluene
PulVI> with [H+]H2Y2 <DA)
(DB)0.02511 TOPO (DAB1
[H2SO4] DAB /\D
0.1980.3940.5900.7860.982
0.9400.2450.1100.06510.0406
0.2990.07360.03190.02040.0108
0.
0.0.0.
00585-
006130049200329
0.6350. 1710.07200.03980.0265
Table - 24
Variation of D of U(VI) with CH+IOrganic Phase : 0.020 F H2Y2 <DA>
0.025 n TOPO (DB>0.020 F H2Y2 + 0.025M TOPO (DAB)
Diluent : Toluene
[H2SO4)M
0. 1980.3940.5900.7860.982
DAB
18.05.702.901.711.08
DA
0.7370. 1800.07900.04400.0263
0.0.0.0.0.
(
0235015401200097100926
/\D
17.5.2.1.1.
250816604
60
Table -25
Variation in D of Pu(VI) and U(VI > with CH2Y2] in presence of
Aq.Phase: 0.2M H2SO4 Diluent: Toluene (TOPO) : 0.0025 M
TOPO
£H2Y2J
F
0.0000.0020.0040.0060.0080.009
DAB
_0.01080.03680.07770.1120.158
Pu(VI)
DA
_
0.003260.01270.02800.04550.0703
A D
_
0.007540.02410.04970.06650.0877
U< VI )
DAB
0.0007470.1800.6661.502.362.91
DA
_0.007340.02840.06510.1110. 145
AD
_
0.1720.6371.432.252.77
Table -26
Variation in D of PulVI) and U(VI) with [TOPO] in presence of H 2Y 2
Aq.Phase: 0.2H ff2SO4 Diluent: Toluene CH2V23 : 0.0025 H
CTOPO]
DAB
Pu(Vl)
DA
IHV
AD DAB AD
0.000r'.0020.0040.0060.0080.010
0.0 .0 .0 .0 .
-505693787892962
0.292 1.080.2130.4010.4950.6000.670
7.11141617
46. 5. 3. 1. 8
6.3810.413.215.016.7
61
2.2.4. ION-EXCHANGE STUDIES OF URANIUM AND PLUTONIUM FROM
MIXED SOLVENT MEDIA
P. M. Hapara, K. V. Chetty, Rajendra Swamp and S.K.Patil
Ion-exchange in solutions containing water miscible organic
solvents such as alcohols, ethers, ketones etc. offer several
advantages in the separation of metal ions^1^. With a view to
find out the possibility of separation of plutonium and uranium
using macroporous (MP) anion exchange resins from the mixed
aqueous-organic solvent media, a systematic study for uranium
and plutonium was undertaken. These studies were carried out
using two quaternary-amine-type MP resins Tulsion A-27 (TA-27)
and Amberlyst A-26 (AA 26) and a tertiary-amine-type Amberlite
XE-270 (AXE-27O>. Out of these, TA-27 is manufactured locally.
Because of the larger surface area, these MP resins combine the
advantage of selectivity offered by high cross linkage with
fast exchange rates therby making them superior to classical
gel-type resins. The batch data obtained for U(V I ) and Pu(lV)
using these resins under different conditions are reported
here.
Preliminary studies carried out on the determination of the
distribution ratio of Pu(IV) using the resins and mixtures of
nitric acid and a number of organic solvents such as alcohol,
acetone and dioxane revealed a high adsorption of Pu(IV) on
these resins with the methanol and acetone. Subsequent
experiments were carried out from HNO3 + methanol
mixtures. The test experiments showed that the plutonium
remained as Pu(IV) in the mixed media. For experiments with
U(V I ) , U-233 was used as tracer.
62
The time of equilibration studies were carried out by
determining the distribution ratio as a function of time. It
was observed that equilibrium was not attained even after six
hours. However, an equilibration time of 3 hours was
arbitrarily chosen for all the experiments.
Variation of nitric acid concentration at a fixed methanol
concentration.
The distribution ratios for Pu(IV) and U(VI) were determined as
a function of nitric acid concentration at 50% methanol
concentration. From the data it was observed that the D values
increased with the increasing acidity upto 3M HNO3 and then
decreased in the case of all the resins used.
Variation of niethanol concentration at a fixed HNO3
concentration.
The distribution data for Put IV) and U<VI ) for the resins
TA-27, AA-26 and AXE-270 were obtained as a function of
methanol concentration keeping nitric acid concentration at 1M.
The distribution ratios were found to decrease initially and
then increase. In order to know the effect of high HNO3
concentration, distribution ratio data were obtained at 7M HNO3
which showed initial increase and then decrease with methanol
concentration. This behaviour was opposite to the one obtained
at 1M HNO3 .
Separation Factor.
From the results it was revealed that the distribution ratio of
U(VI ) was very low as compared to that Pu(IV). Based on the
data separation factors for Pu/U were calculated at different
methano1/HNO3 concentrations for all the resins and are given
in Tables 27 and 28 along with the distribution ratio* data.
High separation factors were obtained at 1M HNO3 towards the
higher concentration of methanol. The separation factors in
63
the case of Amberlyts XE-270 were found to be the lowest as
compared to the other two resins. The results indicate that a
reasonably good separation of plutonium from uranium could be
achieved. Column experiments are being planned to substantiate
this work.
Reference.
1. J.Korkisch.Progr.Nucl.Energy Ser.IX Eds.D.C.Stewert and H.A.Elion,Pergamon Press, 6., 1 (1966 I.
64
Table - 27
Variation of Distribution ratios of Pu(IV) and U(V1) between ion-exchangeresins and (HNO3 + CH3OH) as a function of methanol concentration.
Methanol 1.X
0102030405060708090
0102030405060708090
0102030405060708090
DPu(lV)
53.954.547.61351472524521471653111468
37.030.028.782.688.81733991177471613334
1.820.922.419. 1113.026.361.0193760
3375
0M HNO3values for
U(V1)
1.080.7540.7680.5062.326.492.645.489. 1219.6
2.142.102.940.7321.161.592.868.299.3218.4
0.9420.7730.4060.7390.6660.4181.726.787.818.02
S.F
TULSION
507262
2676339171268716585
AMBERLYST
171410
11377109139142506725
AMBERLYTE !
1.91.25.912.319.563352897
421
3.D
Pu(lV)
A-27
5758901390222335965620648553195545
-
A-26
376616631142421183613457346576437
KE-270
683391131339741126615932073
_
OM HNO3values for
U(VI)
2.733.934.436.308.3011.012.715.315.3-
3.023.374. 186.468.9610.412.914.214.4-
2.603.323.304.735.516.687.617.776.97_
S.F
211226313353433511511248362-
124183199220236347354328447-
269.9
272861111166205297
„
65
Table - 28
Variation of Distribution ratios of Pu(IV) and U(VI) between ionresins and (HNO3 + CH3OH) as a function of methanol concentration.
exchange
fiethanol
X
01020304050576070
Pu(IVI
205428494239529151654057-
33003076
5.0M HNO3D values for1 UIVII
8.088.9110.611.612.713.3--_
S.F
TULSION
254320400456407305--
7.
DPu(lV>
A-27
4417566243983686237720391826-
on HNO3values for
U(VI)
11.411.810.1-
9.759.849.01-_
S.F
387460435-
244207203-_
AHBERLYST A-26
01020304050576070
0102030
4050576070
117522052874353735102931-
22402378
1375174920332161
17871651-
11881150
7.679. 139.27
100.12.112.1-
10. 110. 1
5.735.957.456.89
7.767.43-
5.966.59
153241310354290242-222235
AMBERLYTE
240294273314
230222-199174
2756334232512420166812591086--
XE-270
1881196916131322
922691647
_
10.11.59.6-
8.788.408.40--
7.027.866.27-
6.025.605.96
265290338-190150129--
268250257-
153123108_
66
2.2.5. STUDY ON THE FLUORIDE COMPLEXES OF ACTiNIDES:
MEASUREMENT OF THE STABILITY CONSTANTS OF THE
FLUORIDE COMPLEXES OF U ( I V ) AND Pu(IV) USING
FLUORIDE ION-SELECTIVE ELECTRODE
R.M. Sawant, N.K. Chaudhuri and S.K. Patil
The development of a procedure for the measurement of stability
constants of the fluoride complexes of actinides using a
fluoride ion selective electrode and the values obtained for
pentavalent, hexavalent and trivalent actinides were reported
earl i e r ^ " 3 1 , It was also demonstrated' 4 1 using Th ( 1 V )-f 1 uor i de
system, that the high acidity required for preventing
polymerisation and maintaining the oxidation states of some
tetravalent actinides would not have any adverse effect on the
measurement of the stability constants. The study was then
extended to U(IV) and PulIV) fluoride complexes.
U(IV) perchlorate was prepared by cathodic reduction.
Plutonium was purified by anion exchange and Pu(IV)-
perchlorate was prepared by coulometric reduction.
Concentrations of U ( I V ) and Put IV) were determined by
potentiometry and coulometry, respectively. For the
determination of stability constants, potentials of the
i luoride electrode were measured in the solutions prepared by
adding suitable aliquots of standard fluoride solution to the
mixture containing NaC10/4 , HCIO4 and U(IV) or Pu(IV)
perchlorates using all plastic labwares.
Free F~ and n-bar values, i.e. the average number of F~ ions
attached to metal ion were calculated from the experimental
data following the procedure reported earl ier"-' . The
stability constants were obtained by nonlinear least square
fitting to Bjerrum's function. When the number of constants in
67
t h e f i t t i n g p r o g r a m w a s v a r i e d t h e b e s t f i t , a s m e a s u r e d by
l e a s t v a l u e of c h i - s q u a r e , w a s o b t a i n e d by f o u r c o n s t a n t s . T h e
c o n c e n t r a t i o n s t a b i l i t y c o n s t a n t ; o b t a i n e d i n d i f f e r e n t s e t s
a r e s h o w n i n T a b l e - 2 9 a l o n g w i t h t h e v a l u e s r e p o r t e d i n
l i t e r a t u r e . T h e 6* v a l u e s r e p o r t e d i n t h e l i t e r a t u r e a r e
c o n v e r t e d t o 6 v a l u e s u s i n g d j = 8 8 9 f o r c o m p a r i s o n .
R e f e r e n c e s
1. R.M. Sawant , G.H. R i z v i , N.K. Chaudhur i and S.K. P a t i l , J . R a d i o a n a l .and Nuc l . Chem. 8 9 , 3 7 3 ( 1 9 8 5 ) .
2 . R.M. Sawant , G.H. R i z v i , N.K. Chaudhur i and S.K. P a t i l , J . R a d i o a n a l .and Nuc l . Chem. 9± , 4 1 ( 1 9 8 5 ) .
3 . M.A. Mahajan, R.M. Sawant , N.K. Chaudhur i and S.K. P a t i l , Radiochem. andR a d i a t i o n Chem. Symp., T l r u p a t i , Dec. 1986.
4 . R.M. Sawant and N.K. C h a u d h u r i , Radiochem. and R a d i a t i o n Chem. Symp.Bombay, Feb ( 1 9 8 8 ) .
5 . B. Noren, Acta Chem.Scand . , 2 1 , 9 3 1 ( 1 9 6 9 ) .6. I . G r e n t h e and J . V a r f e l d f , Acta Chem. S c a n d . , 2 3 , 9 8 8 ( 1 9 6 9 )7. V.N. Krylov and E.V. Komarov, Rad iokh imiya , U_, 1 0 1 ( 1 9 6 9 ) .8. S.V. Bagwade, V.V. Ramkrishna and S.K. P a t i l , J . l n o r g . N u c l . Chera.
38_, 1 3 3 9 ( 1 9 7 6 ) .
68
Stability constantsperchlorate medium.
Metal Ionic Strengthion /method*
U(IV) 1M (H,NaC104)/Fe
1M (H,NaCI04)/Fe
1M (H,NaCI04l/Fe
1M (H,NaC104)/Fe
1M (H,NaClO4)/Fe
4M HC104/Fe
4M <H,NaCI04)/Red
Put(V) 1M <H,NaCI04>/Fe
1H (H,MaCI04l/Fe
2H HCI04/Dis
2M HCI04/Cix
1M HC104/Cix
of Ui
log 6]
8.48
8.45
8.50
8.40
8.47
8.49
8.32
7.61
7.64
7.59
7.40
7. 15
Table •
1 IV) fc
L log
14.
14.
14.
14.
14.
14.
14.
14.
14.
13.
-
-
- 29
Pu(lV)
B2
,66
59
72
69
52
62
19
77
69
51
Fluoride
log fi3
19.51
19.34
19.59
19.59
19.37
19.53
18.30
20. 11
20.23
-
-
-
log
23
23
23
23
23
26.
25.
-
complexes
64
.92
.50
.75
.75
.88
07
94
Ref
This work
•
1
II
f
5
6
This work
•
8
7
7
in
*Fe-F!uoride electrode, Red-Redox,Dis-Distribution, Cix-Cation exchange.
69
2.2.6 STUDIES ON THE EFFECT OF TBP AND n-OCTANOL ON THE
EXTRACTION OF Pu(IV) BY MOPPA
P.D.Mithapara, V.Shivarudrappa,S.G. Marathe and H.C.Jain
During the studies on the recovery of plutonium from phosphoric
acid waste solutions using MOPPA, back extraction of
Plutonium was achieved by the addition of TBP or n-octanol and
contacting with H2SO4 . Studies were therefore, carried out to
understand the effect of TBP and n-octanol on the extraction of
Pu(IV) by MOPPA from H2SO4 solutions.
Distribution ratios (D-values) were measured as a function
of TBP or n-octanol concentrations at different MOPPA
concentrations. The results are given in Fig 3. It was observed
that at low concentration of the synergists (when the ratio of
the synergist/MOPPA was about 0.4), a maximum in the D-values
was observed which decreases with further increase in the
concentration. The effect of variation of D-values as a
function of H2SO4 concentration at different synergist/MOPPA
ratios for both TBP and n-octanol is given in Fig 4. A minimum
in the D-values was observed at about 2M H2SO4 in the case of
TBP and at about 5M H2SO4 in the case of n-octanol when ratio
3f the synergist/MOPPA was 100. A large decrease in the D-
vaiues of the order of lO^-lO4 indicated a large negative
synergism which is responsible for the back extraction of
plutonium. It is reported that at high concentrations of the
synergist,deactivat ion of the active hydrogen atoms by
increased hydrogen bonded interaction between the synergist and
the extractant is responsible for the observed negative
synerg i sm.
1.1
O '
A 0.00i)5FMOn-A *; I . - J ' I A N C L
D 0.005F.V,O?vA - TBP . " , 4
O 0.005FMCPPA + n-CCTANO:. ̂
I 1 ' 2
1.0- r — -
" • JJ,0.8
i_ J _ JO. 6
SYNERGIST CONC. 10
F i g 3 . V A R I A T I O N OT L(JU U f;f- l ' w ( l V ) WiTIiS Y N E R G I S T ' S CONCliNTHAT J'.)N .AQUEUUS IMIABE : 1MORGAN
EUUS IMIABE : 1M H^JOA,A N I C I ' H A i i E : M()p: 'A IN X Y L F N H .
O 0.00 5FMCTA • ^ .•:.•..r ; - r
O 0.005^ MOf'I'A + 0..M- IHi- |
• 0.005F MOPPA + 0 5 f r.-GCTANQI
0.005F MOPPA + G.5F n -OC1A' ;QL !
.. ._ j
CONC.(M)
0 . VARIATION PI- LOT, 1) ;JI- i ' u ( I V ) W I1\ii i^^O/i fONcr.NTKAT i > JN A'i D I F ; : L K L - N T
SYNERCi I . ' T / r i O r P A RAT I OH.
70
References.1. V. Shivarudrappa, P.D. Mithapara, S.G. Marathe and H.C.Jain,
CT-7, Preprint volume, Radiochem. and Rad. Chem. Symp.,Bombay(1988).
2. G.W. Mason, S. McCarty and Peppard,D.F., J.Inorg. Nucl.Chem.24, 967<1962>.
3. T.K.S. Murthy, V.N. Pai and R.A. Nagle, Rep.IAEA-SM-135/11(1971).
2.2.7 Solvent Extraction Studies of U ( V 1 ) by MOPPA.
P.D. Mithapara, V. Shivarudrappa and H.C. Jain.
Work has been initiated to study the extraction behaviour of
U(VI) by MOPPA from different acidic media using 2 3 3 U tracer.
Distribution ratios (D-values) of U(V1) were measured as a
function of extractant concentration and H + concentration using
a solution of MOPPA in toluene as the diluent. The plot of log
D Vs log MOPPA concentration is shown in Fig 5. A slope of +3
was obtained with ail the acids indicating a direct third order
dependancy of D values on the extractant concentration. The
dependancy of D on H + concentration is shown in Fig 6. A
slope -2 indicated an inverse second order dependancy of
-values on H + concentration. Based on these results, an
expression for the equilibria involved may be written as
foilows :
UO^"1" + 3H 2Y > U0 2(HY)^H ?Y + 2H +
where H2Y = MOPPA. Further work is in progress in order to
study the extraction in different diluents.
10
Q 1.0
0.1
A
o
•
: HCIO4 ( 1.0 M )
: HCl (1.0 M)
: HNO3
SLOPE= ~3.0
J L J ! I 1
20
F i g 5 . V A R I A T I O N OF D WITH MOPPA CONCENTRATION,
4 6 8 10
20
10
a : HCLO4
o : HCl
A : H N O o
: H2SO4
SLOPE = 2.0
j L
0.1 0.2 0.4 0.6 1.0 2.0
jt. G. V A R I A T I O N O P D W I T H II C U H C 1 - N T K A T I ON .
71
2.2.8. RECOVERY AND PURIFICATION OF PLUTONIUM FROM PLUTONIUM
DIOXIDE SCRAP AND MIXED OXIDES AND CARBIDES.
H.S. Sharma, J.V. Kamat, N. Gopinath, N.B. Khedekar,
R.K. Duggal and H.C. Jain.
Plutonium dioxide scrap (280 g) was generated during the course
of dissolution of large quantities of sintered plutonium
dioxide in nitric- hydrofluoric acid mixture and contained 50%
by weight of plutonium. Analyses indicated that the scrap
material also contained 12% by weight of carbon and 1200 ppm of
f1uor ide.
Dissolution experiments indicated that it was not possible to
dissolve the scrap material directly in boiling sulphuric acid-
nitric acid mixture (1:1). Carbon was removed by heating the
scrap at 900°C. Further dissolution was tried in sulphuric-
nitric-perchloric acids mixture. The scrap in lots of 10 g was
dissolved in boiling 15M nitric acid,9M perchloric acid,and IBM
sulphuric acid mixture (5 ml + 5 ml + 40 ml) under reflux.
Plutonium thus recovered was precipitated as oxalate in lots of
50g. Plutonium oxalate was finally converted to oxide by
heating at 500°C. About 160 g of plutonium from scrap was
recovered.
About 30 g of plutonium was recovered by dissolving mixed oxide
and oxidised mixed carbide material in 15M nitric acid and
nitric - perchloric - sulphuric acids mixture respectively.
The recovered plutonium was converted to oxalate and finally to
oxide form.
72
2.2.9. RECOVERY AND PURIFICATION OF PLUTONIUM FROM
ANALYTICAL WASTE.
R.B. Manolkar, S.P. Hasilkar, Keshav Chander and
S.G. Marathe.
20g of plutonium was recovered from different types of
analytical wastes. The plutonium present in about 20 litres of
waste was precipitated as hydroxide. After dissolution of the
hydroxide in HN03; plutonium was purified by anion exchange
technique. Plutonium in the purified solution was precipitated
as oxalate which was heated at 500°C to get pure
2.2. 10. SEPARATION OF PLATINUM FROM PLUTONIUM-PLATINUM SOLUTIONS
S.P. Hasilkar, Keshav Chander and S.G. Marathe.
It was felt necessary to have a simple procedure by which
platinum associated with plutonium in solution could be
separated in pure form without significant alpha contamination.
Very little is known about the separation of platinum from
plutonium and other radioactive solutions. Studies were
therefore carried out to see whether separation, of platinum
could be achieved through its precipitation in a suitable
med ium.
The redox potentials data indicated that Tit III) can reduce
platinum present in any oxidation state, to platinum metal.
Therefore to the Pt-Pu solution, Ti(II I) was added in HC1
medium. Platinum was precipitated as metal. The experiments
have shown that the metal precipitation is quantitative and
very small amount of plutonium is associated with the
precipitate. Quantitativeness of the metal precipitation as
73
well as decontamination from plutonium was checked as follows:
about a milligram of platinum was irradiated in the reactor
APSARA under the neutron flux of 1012/cm2/sec. Known activity
(107dpm) of 197Pt(18.3h> was taken and added in solution
containing varying amounts of platinum (5-25mg). After the
precipitation, activity in the supernate as well as in the
precipitate was assayed by the peak area measurements
corresponding to 191.4 kev gamma ray energy. Negligible counts
were obtained in the supernate and nearly all the activity
added was carried in the precipitate. Also metal precipitate
was weighed on a preweighed Whatman filter paper No. 541.
The observed weights of platinum metal precipitate compared
well with the expected value. The platinum metal
precipitate was washed repeatedly (4-5 times) with 1M -
2M HNO3 and then employing ultrasonic cleaning. The
decontamination factor of 107, as observed by alpha-
scintillation counting, could be obtained. This scheme of
separation is proposed to be employed for the solutions
containing gram levels of Pt-Pu. Dissolution of the
precipitate in HC1 and reprecipitation of the same was observed
to give high decontamination from plutonium.
2.2.11. RECOVERY OF HEXAMETHYLENE TETRAM1NE AND UREA FROM WASTE
SOLUTION GENERATED FROM THE AMMONIA WASHING OF U0 3 GEL
PARTICLES PREPARED BY INTERNAL GELATION PROCESS.
S.K.Mukerjee, J.V. Dehadraya, T. U.Vithairao, V.N.Vaidya
and O.D. Sood.
Work on extraction of HMTA and urea from wash solution
containing HMTA, urea, NH4NO3 , HCHO and methylol urea has been
initiated. Since NH4NO3 and HMTA, when present in high
concentration react vigorously (explosive reaction) on hsating,
74
waste volume cannot be reduced just by distillation. Hence it
was decided to remove nitrate by ion exchange,using DOWEX 1 x 4
anion exchange resin. Resin in the OH form was used to avoid
contamination from any more constituent. Resin was
regenerated by IN NaOH. The eluent containing HMTA, urea,
HCHO, methylol urea and NH4OH was distilled under vacuum.
Distillate contained NH4OH and some HCHO. The concentrated
solution was analysed for free and bound formaldehyde by
Iodometric estimation. From the total amount of formaldehyde
present in the wash solution it was found that about 94% of
HMTA that was initially present in the feed solution remains
unused. About 2% of HCHO was present in the concentrated wash
solution. Efforts to remove HCHO by vacuum distillation
failed,as removal of HCHO was accompanied by hydrolytic
decomposition of HMTA and the amount of HCHO in solution
remained about 2%. Work is being carried out. to bring down
HCHO further.
Estimation of HMTA and Urea in Solution.
HMTA solution in water gives an analytical peak in UV region at
197nm, but urea peak at 191nm causes interference. However, at
205 nm, HMTA can be easily estimated in presence of urea.
Urea is estimated from the knowledge of total nitrogen and
nitrogen from HMTA.
75
2.2.12. STUDIES ON THE BEHAVIOUR OF PLUTONIUM IN ALKALINE MEDIA
A.V. Kadam, M. Ray, I.C. Pius, M.M. Charyulu,
C.K. Sivaramakrishnan and S.K. Patil.
The data on the distribution of Put IV) and Pu(VI) between AJ2O3
or Amberlyst A-26 (MP) and carbonate medium had indicated
feasibility of removal of plutonium from aqueous alkaline waste
streams. Preliminary column experiments were carried out tooi
explore the feasibi1ity^removal of plutonium from carbonate
medium. Two ion exchange columns were prepared, one with 5ml
of chromatographic grade A 1 2O3 and the other with 5ml of a
strong base anion exchange macroporous resin Amberlyst
A-26(MP). Feed solution containing 9.7ng/ml of piutonium(IV) in
0.25M carbonate was prepared and its pH was adjusted to 9.5.
This feed solution was passed through above two columns
separately at a flow rate of 0.5 ml/min. Samples from the
column effluents were collected at regular intervals and
plutonium content was determined radiometrically. Loading was
continued till 10% plutonium breakthrough was obtained in the
effluents. The 10 percent plutonium break-through capacity was
found to be 2.5 mg/ml for A12O3 and 0.6 mg/ml for Amberlyst A-
26 (MP) under the experimental conditions used.
Similar experiments were carried out with Pu(VI) in carbonate
medium with Amberlyst A-26 (MP). A feed solution of 100ng/mI
of plutonium (VI) in 0.25M Na£C03 at pH-12 was passed
through the anion exchange column of 5 ml bed volume at the
flow rate of 0.5 ml/min until 25% plutonium breakthrough was
reached. Potassium persulphate was used as holding oxidan.t for
Pu(VI). The 25% plutonium breakthrough capacity was found to
be 12 mg/ml of resin bed indicating the feasibility of removal
of plutonium from carbonate medium by using Amberlyst A-26
res i n.
76
2.3 PROCESS CHEMISTRY
2.3.1. STUDIES ON THE EVALUATION OF DIFFERENT ANION EXCHANGE
RESINS FOR PLUTONIUM PROCESSING
D.G. Phal, S. Kannan, Kum. N.N. Mirashi,
R.D. Bhanushali, V.V. Ramakrishna and S.K. Patil.
In continuation of the work on the evaluation of different
resins for plutonium processing1 *-1, some more resins were
procured and the results of the investigations carried out with
these are reported here.
Measurement of Distribution Ratios
The experimental procedure adopted for measuring the
distribution ratio (D) values is the same as described earlier.
Among the macroporous (MP) resins studied earlier, the
indigenously available Tulsion A-27 (MP) with the particle size
in the range of 0.3 to 1.2 mm, (15-50 mesh) gave the best
performance with reference to plutonium breakthrough capacity
as well as separation of plutonium from uranium. Since this
resin gave a higher plutonium breakthrough capacity when the
loading was done at a higher temperature and/or a longer
residence time; it was decided to study the variation of D
values of Put IV) with time and temperature. The results
obtained are given in Table -30. It is seen that the D values
for similar equilibration times at two temperatures are quite
close to each other suggesting that the better kinetics is
responsible for a better loading at high temperature rather
than any change in equilibrium conditions.
Anticipating that the same resin (Tulsion A-27, MP) with a
smaller particle size may give an overall improved performance,
the resin in 50-100 mesh size was procured and studies were
conducted with it. The U(VI) D values were obtained for this
77
resin as well as the normally used Dowex 1x4 gel type resin and
they are compared in Table - 31 with those of Tulsion A-27, MP
<15-50 mesh) obtained earlier. It is seen that practically
there is no change in the LI (VI ) D values with tha change in the
particle size of the resin. Though the gel type resin gave
slightly lower U(V1) D values, its performance from uranium
separation point of view was already demonstrated^1^ to be poor
as compared with the macroporous resins.
The results on a comparison of the distribution ratios of
Put IV) obtained with A-27(MP) of two mesh sizes are given in
Table - 32. It is seen that there is a marked improvement in
the equilibrium D values with smaller particle size resin.
The distribution ratio data for Pu(IV) obtained with some more
resins are given in Tables 33 and 34. All these resins seem to
have a good absorption power for Pu(lV) except for Tulsion
A-12X. However the local gel-type resin Tulsion, A-35 (gel)
gave the highest D values and further study is planned with the
same.
Study of the Plutonium breakthrough capacity and elution
behaviour of Tulsion A-27, MP (50-100 mesh) resin.
Using a 10 ml resin bed of this resin and a feed solution with
the composition of 1 g/1 of plutonium and 7 g/l of uranium in
7M nitric acid the 10% plutonium breakthrough capacity was
found to be 102 g/l with a residence time of 15 minutes and
110 g/l with a residence time of 30 minutes. These values are
much higher than the corresponding figures of 37 g/I and 58 g/l
with this resin with a bigger particle size [ 1^. With 0.5 M
nitric acid 99% of the ptutonium held on the resin could be
eluted in 5 bed volumes. Though these features were found to
be very satisfactory for plutonium recovery the studies
revealed that the resin with a smaller particle size crumbled
78
after a couple of runs to become like powder, thus preventing
the flow of liquid through the resin bed. Efforts are on to
procure a physically and more stable product otherwise
equivalent to this resin.
Studies on Plutonium recovery by anion exchange from HF
containing nitric acid solutions.
Addition of HF to nitric acid was found to improve the leaching
plutonium from the gloves and PVC sheet used in the boxes used
for fabrication of piutonium-bearing fuels. It is known that
the presence of fluoride ion decreases the distribution ratio
of Pu(IV) between nitric acid and anion exchange resin thereby
reducing the plutonium breakthrough capacities of the resin
columns. Addition of Alt I I I), which complexes flouride ion
effectively, is reported to help in arresting the fall in the
plutonium breakthrough capacities. Using three macroporous and
one gel-type anion exchange resins experiments were conducted
to study the feasibility of plutonium recovery the results of
which are presented here. Distribution ratios of Put IV) from 7M
nitric acid, in the absence and the presence of HF were
measured with alI the four resins and the data obtained are
given in Table - 35. As expected, the presence of HF
decreased the values due to the complexing of Put IV) by
fluoride ions in aqueous solution. Addition of Alt I II) is seen
to improve the D values of Put IV). From the data it is seen
that all the four resins studied may, more or less, behave
similar to one another for plutonium recovery. The breakthrough
capacities for Put IV) for these resins were obtained using
10 ml beds and a feed solution containing 7.5M nitric acid,
0.31 mg/ml of plutoniuni and 0.03M each of HF and aluminium
nitrate with residence time 15 minutes.
The plutonium breakthrough (bt) capacities obtained under the
experimental conditions were: 14.7mg of Pu/ml resintlOX bt) for
79
Amberlite XE-270 MP.weak base,27.2mg of Pu/ml resin (2% bt) for
Amberlyst A-26 MP strong base,3O.5mg of Pu/ml resin (2.5% bt)
for Tulsion A-27 MP strong base, and 53.9 mg of Pu/ml resin
(0.5% bt) for Biorad AG-1X4, strong base, gel type resin.
The loadings for the last three beds coutd not be continued
upto 10% bt due to the problem of choking of the resin beds,
apparently due to the presence of some fine solids in the feed
solution. Such a problem was not encountered with the resin
AXE-270 and this may be due to its different packing
characteristics. As a result this resin was chosesn for the
recovery purpose inspite of its poor capacity as compared with
others.
Using a 500 ml resin bed of AXE-270, about 4.3 g of plutonium
in 15 litres of nitric acid, containing HF, was quantitatively
recoverd.
Reference.
1. FCD Annual Report 1986.
80
Table -30
Variation of the distribution ratio (D) of Put IV) with equilibration time[HN03 ] = 7.5M
Initial Aq [PuUVI] = Spg/mlResin : Tulsion A-27 IMP), 15-50 mesh
Equi1ibriumTime, min.
102030405060
* Reference [1]: Table 30.
25°
331646899-
10901213
D of PuC*
( IV) at40°C
2415647 9496510631140
Variation ofconcentration.
Table - 31
the distribution ratio(D) of UIVI;
Initial Aq CUIVN = lOjjg/m!Time of equilibration = 3 hours.
with nitric acid
CHNO3]
23456789
10
Tuls ion(15-50
1.3.5.8.11.11.11.9.7.
A-271MP)mesh) *
216600026
D of U(VI) with
Tulsion A-27IMP)(50-100 mesh)
0.973.64.98.811.013.011.09.210.0
Dowex 1x4(gel)(50-100 raesh)
_--
6.36.8
10.08.25.95.9
« Ref. El], Table 27.
81
Table - 32
Variation of the distribution ratio (D) of Pu(IV) with nitric acidconcentration
Initial Aq [PutlVIl = 5>»g/mlTime of equilibration = 3 hours. Resin-Tulsion A-27(MP)
£HN03] D of Pu(lV) with the mesh size
(15 - 50)« (50-100)
12345678910
135813529760510401610186016101150
35211531960151022802700286026902130
* Ref. [11, Table 28.
Table - 33
Variation of the distribution ratio (D) of Pu(lV) with nitricconcentrationInitial Aq tPu(IV)] = 5jtg/ml Resin: Strong base,Time of equilibration = 3 hrs. Type I*
D values of Pu(IV) with the resins[HN03]M Duolite Duolite Duolite Amberlyst Tulsion
A-113 A-161 A-101D A-26 A-35(MP) (MP) IMP) (HP) (Gel)
1 14 30 15 36 262 46 87 47 116 933 109 291 145 449 3324 262 390 330 530 6595 592 1050 586 832 13106 1230 1290 1150 1050 19807 1420 1550 1690 1780 24308 1600 1630 1850 2210 48309 1090 1470 1790 1950 369010 734 923 846 1580 1280
Resin Type 1* _ > R-N+(CH3>3
acid
82
Table - 34
Variation of the distribution ratio <D> of Put IV) with nitric acidconcentration
Initial Aq CPuUV)) = 5jig/m(Tine of equilibration = 3 hrs.Resins - All macroporous,Type II
D values of Pu(IV) with the resins
CHNO3] Strong base, Type II Ueak-base .
n - -Duolite Duolite Tulsion DuoliteA-162 A-102D A-12X A-368
1 13 11 3.7 322 68 42 6.5 1193 153 102 19.0 2444 230 205 25.0 3105 381 448 37.0 5366 565 742 56.0 5857 723 U40 79,0 7038 838 1330 79.0 8189 684 982 73.0 53510 . 578 408 53.0 424
Resin Type 11 — > R - N+(CH3>2CH20H
Table - 35
Distribution ratios of Pu(IV) from 7M nitric acid in the presence of HF andA H N 0 3 ) 3 .
Time of equilibration = 3 hours; Temperature = 25*C
Resin [HF1=O tHF]=0.025M tHFJ=0.05M CHFJ=0.05M £HF)=0.025M{AI(NO3)3J £A1(NO3)3 j
=0.05M =0.025H
Amber 1iteXE-270CMP)AmberlystA-26(MP)TulsionA-27(MP>BioradAG 1x4(GEL)
1120
1680
2140
2560
738
880
1240
1140
726
823
1160
948
792
934
1180
1340
1010
1250
1930
1330
83
2.3.2. RECOVERY AND PURIFICATION OF PLUTONIUM FROM FUEL
FABRICATION SCRAP FOR RECYCLING
M.M.Charyulu, N.K.Chaudhury, D.R.Ghadse, A.R.Joshi,
A.V.Kadam, U.M.Kasar, M.A.Mahajan, M.S.Oak, S.M.Pawar,
I.C.Pius, R.K.Rastogi, M.Ray, V.B.Sagar, R.M.Sawant,
C.K. Sivaramakrishnan and S.K. Patil.
Scrap generated during the fabrication of plutonium bearing
nuclear fuels has to be necessarily processed for recovery and
recycling of valuable plutonium. During the fabrication of
uranium - plutonium mixed carbide fuels by carbothermic
reduction, part of the plutonium volatilises and gets
deposited on various components of the furnace. The quantities
of p l u t o n i u m v o l a t i l i s e d are s i g n i f i c a n t , p a r t i c u l a r l y in case
of FBTR fuel, which has high (70%) plu t o n i u m c o n t e n t . The
p l u t o n i u m thus d e p o s i t e d being highly r e a c t i v e , it is normally
leached w i t h a n o n - o x i d i s i n g m e d i u m like H C 1 . As a part of the
p l u t o n i u m recovery and r e c y c l e o p e r a t i o n for fuel f a b r i c a t i o n ,
large v o l u m e s of HC1 s o l u t i o n c o n t a i n i n g 4-50 g/1 of plu t o n i u m
along with U, W, Cr, Mo etc. received from R a d i o m e t a 1 1 u r g y
Division was processed for plutonium recovery/purification.
Such large volumes of HC1 containing significant quantities of
Plutonium have not been encountered in our laboratory in the
past, and a suitable method had to be evolved for recovery and
purification of this plutonium. Large volumes and the corrosive
nature of the medium demanded that the method to be developed
should aim at (a) minimum operations (b) minimum waste
generation and !c) the product of required purity.
BA
2.3.2.1. Preliminary trial experiments.
Direct precipitation of oxalate from HC1 medium.
Preliminary trial experiments were carried out using T h M V ) as
a stand-in for plutonium, to develop a suitable method for
processing the large volumes of HC1 medium. Since the final
product required for recycling is PuO£ produced through the
oxalate route, direct precipitation of Th(IV) as oxalate from
HC1 medium and its subsequent conversion to oxide was
attempted. Analysis of ThO2 thus produced indicated the
presence of 1000-1200 ppm of chloride in the product which is
rather too high to accept. A hydroxide precipitation and
dissolution of hydroxide precipitate in nitric acid was
considered desirable to remove the bulk of chloride prior to
oxalate precipitation.
Precipitation of Plutonium oxalate from HNO3 med ium.
A trial experiment with 2 litres of HCI solution containing
about 20g of plutonium was therefore carried out. In this,
the plutonium was precipitated as hydroxide using sodium
hydroxide,, and the resulting plutonium hydroxide was dissolved
in nitric acid after several washings of the precipitate with
dilute ammonium nitrate solution. Having thus eliminated the
bulk of chloride, oxalate precipitation was carried out in a
stainless steel container. Prior to addition of H2O2 for
adjusting the oxidation state of plutonium and addition of
oxalic acid for precipitation, the solution was heated to 55-
60°C. During this heating process, the solution started
reacting with the container, as seen by the effervescence,
probably due to the presence of chloride ions, indicating the
non- compatibility of stainless steel vessel with the plutonium
solution.
85
Precipitation of oxalate from HNO3 medium after double
hydrox ide preci pi tat ion.
In view of this, a third trial experiment was carried out
wherein after the initial conversion of the medium from HCi to
HNO3, plutonium was precipitated as oxalate in a plastic
container kept in a waterbath which was heated to have the
temperature of plutonium solution to «* 55-60°C during oxalate
precipitation. The oxalate produced was washed, dried and
finally converted to PuG"2 by heating at 500°C in a stream of
oxygen. Analysis of the PuO2 still showed the presence of 260
ppm of chloride. In yet another experiment, one more hydroxide
precipitation of plutonium from the HNO3 medium was
incorporated for further elimination of chloride impurity
before oxalate precipitation in a plastic container. The oxide
obtained from this oxalate still showed the presence of 150 ppm
of chloride and also 5 ppm of boron, indicating need for
further purification to meet the specification of PUO2 powder
used for fuel fabrication. In view of this, an anion exchange
purification process for plutonium was incorpoated prior to
oxalate precipitation.
2.3.2.2 Anion exchange purification of plutonium.
For this, the entire HC1 solutions were converted to HNO3
medium through plutonium hydroxide precipitation and
redissolution of the resulting hydroxide in HNO3 in several
batches. Concentration of plutonium in 7M HNO3 medium,
varied between 30-60g/litre along with l-10g/litre of uranium.
The use of conventional gel type anion exchange resins like
Dowex 1x4 for purification of plutonium from such solutions has
certain limitations due to rather slow kinetics of plutonium
uptake by the resin. Literature survey indicated that the
raacroporous resins have faster kinetics compared to gel type
resins, resulting in better uranium washing and better
86
p l u t o n i u m e l u t i o n . In v i e w of t h i s , a s t r o n g b a s e m a c r o p o r o u s
a n i o n e x c h a n g e r e s i n A m b e r l y s t A - 2 6 w a s c o n s i d e r e d m o r e
s u i t a b l e f o r p u r i f i c a t i o n of p l u t o n i u m f r o m s o l u t i o n s
c o n t a i n i n g f a i r l y h i g h c o n c e n t r a t i o n s of p l u t o n i u m . T h e
l i t e r a t u r e s u r v e y r e v e a l e d t h a t t h i s r e s i n h a s n o t b e e n
e x p l o r e d s o f a r f o r l a r g e s c a l e p l u t o n i u m p u r i f i c a t i o n .
Ion e x c h a n g e c o l u m s e t - u p .
S i n c e l a r g e v o l u m e s a r e i n v o l v e d , a l a r g e s i z e g l a s s c o l u m n of
d i m e n s i o n s 1 0 0 m m d i a & 3 5 0 m m long, f i t t e d w i t h a G - l g l a s s f r i t
a t t h e b o t t o m a n d a 1 0 0 0 ml r e s e r v o i r b u l b w i t h a g r o u n d g l a s s
s t o p p e r ( B - 3 4 / 3 5 ) a t t h e t o p w a s f a b r i c a t e d a n d s e t u p . T w o
l i t r e s of A m b e r l y s t A - 2 6 r e s i n w a s p a c k e d i n s i d e t h e c o l u m n .
In v i e w of t h e long c o n t i n u o u s o p e r a t i o n e n v i s a g e d m o s t of t h e
• o p e r a t i o n s l i k e l i f t i n g of the f e e d / w a s h / e l u a n t e t c . f r o m t h e
fsed bottle to the column head were automised using suction.
The entire line from the closed feed/wash eluant container to
the column head down the column connection to the receiving
b o t t l e w e r e a l l a i r t i g h t a n d o n e s i n g l e a i r s u c t i o n p o i n t
c o n n e c t e d t o t h e f i n a l r e c e i v i n g b o t t l e p r o v i d e d t h e r e q u i r t d
l i f t o f t h e s o l u t i o n a n d s m o o t h r u n n i n g o f t h e c o l u m n . A
s c h e m a t i c d i a g r a m o f t h e e n t i r e s e t u p i s p i v e n in F i g 7 . A f e u
l e a k t i g h t v a l v e s i n c o r p o r a t e d a t t h e b o t t o m o f t h e g l a s s c o l u m n
a n d t h e s u c t i o n t u b e s p r o v i d e d g o o d c o n t r o l o f f l o w r a t e s .
S i n c e t h e f e e d s o l u t i o n h a d s o m e u n d i s s o l v c d m a t e r i a l , a
c y l i n d r i c a l t u b e p a c k e d w i t h q u a r t z w o o l w a s i n c c r p o r a t e d
b e t w e e n t h e f e e d b o t t l e a n d t h e c o l u m n h e a d w h i c h r •? I..-, i n c d a l l
t h e s o l i d p a r t i c l e s , p a s s i n g o n l y t h e c l e a r p l u t o n i u m s o l u t i o n
to t h e ion e x c h a n g e c o l u m n .
C o l u m n O p e r a t i o n s .
C h l o r i d e f o r m o f t h e r e s i n w a s c o n v e r t e d t o n i t r a t e f o r m b y
c o n t i n u o u s w a s h i n g s w i t h H N O 3 u n t i l t h e e f f l u e n t w a s e n t i r e l y
f r e e f r o m c h l o r i d e . T h e e n t i r e p l u t o n l u m w a s p r o c e s s e d i n s i x
GLASSWOOL
-I .D. » 10 cms.h = 26 cms.
I.D. = 7cms.K = 22 cms.
PEEDSOLUTION
-SAMPLINGSYSTEM
TO
SUCTION^
GI-FRIT
Gi-FRIT
F i g 7.SCHEMATIC DIAGRAM OF ION EXCHANGE COLUMN SET-UP.
87
r u n s , o n e a f t e r the o t h e r u s i n g the s a m e r e s i n , a f t e r
r e c o n d i t i o n i n g a f t e r e a c h run. P l u t o n i u m in 7tt H N O 3 feed
s o l u t i o n w a s a d j u s t e d to Pu( IV ) u s i n g NaNC>2 and w a s c o n f i r m e d
by its e x t r a c t i o n by 0.2M H T T A f r o m 1M H N O 3 . P l u t o n i u m
s o l u t i o n w a s c a r r i e d at flow r a t e of 1 litre per h o u r . L o a d i n g s
w e r e c o n t i n u e d until the e n t i r e bed of ion e x c h a n g e resin w a s
n e a r l y loaded to its c a p a c i t y as i n f e r r e d by the a n a l y s i s of
the c o l u m n e f f l u e n t for p l u t o n i u m c o n t e n t . W a s h i n g s w i t h 7M
H N O 3 w e r e c a r r i e d o u t at the rate of 1 litre per h o u r . A total
of 6 bed v o l u m e s (12 l i t r e s ) w a s h i n g s w e r e c o l l e c t e d . E l u t i o n
of loaded p l u t o n i u m w a s c a r r i e d out w i t h 0.5M H N O 3 at the
r a t e of 0.25 l i t r e s per hour (8 h o u r s per bed v o l u m e ) .
F o r e c u t s at the s t a r t i n g of e l u t i o n w e r e col lee ted s e p a r a t e l y ,
s i n c e m o s t of the p l u t o n i u m w a s e l u t e d in the f i r s t two bed
v o l u m e s . F u r t h e r e l u t i o n (from 3rd bed v o l u m e o n w a r d s ) w e r e
c a r r i e d o u t at the r a t e of 0.5 litres per h o u r . Total S bed
v o l u m e s e l u t i o n w a s used in e a c h run.
S a m p l e s w e r e c o l l e c t e d at f r e q u e n t i n t e r v a l s d u r i n g l o a d i n g ,
w a s h i n g and e l u t i o n . L o a d i n g and w a s h i n g s a m p l e s w e r e a n a l y s e d
by r a d i o m e t r i c a s s a y and the c o n c e n t r a t e d f r a c t i o n s of the
e l u t e d p l u t o n i u m w e r e a n a l y s e d by redox t i t r i u e t r y ^
O n e e n t i r e c o l u m n o p e r a t i o n right from s t a r t i n g to the end of
e l u t i o n took a b o u t 6 0 h o u r s of n o n - s t o p o p e r a t i o n s f o l l o w e d by
a n o t h e r 15 h o u r s for a n a l y s i s of a!1 the s a m p l e s . T h i s is in
a d d i t i o n to the time taken for p r e p a r a t i o n of the c o l u m n for
e a c h run ( c o n d i t i o n i n g ) as well as for the d i s p o s a l of l a r g e
v o l u m e s of liquid w a s t e g e n e r a t e d .
88
Performance characteristics of the ion exchange column.
At the end of the first run with the Amberlyst A-26 anion
exchange column, the following observations were made.
Amberlyst A-26 (M.P) resin gave satisfactory results with
75-80g of plutonium per litre capacity under experimental
cond i t ions.
Channelling was observed, but this did not result In loss
of appreciable amounts of plutonium to loading effluents.
A high degree of decontamination from uranium was achieved
in the product as confirmed by mass spectrometric
analysis of the feed and product solution for uranium.
Loading and washing effluent contained a total of 3 g of Pu
alongwith all Uranium in 16 litres and had to be processed
for further recovery of plutonium.
Plutonium elution behaviour was excellent with about
355b of piutonium being eluted in just 2 bed volumes.
However, the remaining 5X of plutonium needed 3 more bed
volumes for complete elution of plutonium (Fig 8)
Spectrographic analysis indicated that the eluted plutonium
is free from metallic and boron impurities.
The concentration of plutonium in the product solution was
suitable for precipitation of plutoniuni as oxalate.
Incorporation of weak base Macroporous anlon exchange resin,
Amberllte XE-27O column In series.
As mentioned above, the plutonium escaping to the effluents
from the 1st Amberlyst A-26 resin column during plutonium
loading had to be recovered. A weak base macroporous anion
exchange resin, Amberlite XE-27O was chosen for this, which
had shown favourable recovery characteristics, earlier for
solutions containing low plutonium concentrations and higher
Uranium concentrations. A 220 mm long, 70 mm dla glass column
3
UJ
100 h
80 -
6 0
4 0 -
2 0 -
-
-
1.32
4 6 . 33
94. 87 98. 22 99 38 99 89 100
FORE.CUT 1
ELUTION RATE0 . 2 5 L / H r( FOR FIRST 2
BED VOLUMESAND 0 . 5 L / H rSUBSEQUENTLY
VOLUME ELUTED ( I N TERMS OF BED VOLUMES)
QUJt—Z>in
OV
40
30
2 0
10
r\
-
-
1.32
45.01 %
7B.77g
48.
84.
547.
95 g
3.35 7.5.87g
1.16 7o2.04g
0.0.
517-89g
0.0
11 7.21g
)S t B V 2ndB.V. 3 rdB.V 4 fhB.V 5 t h B.V 6 t KB.V
VOLUME ELUTED ( IN TERMS OF BED VOLUMES)
F i g 0 . ELUTION OF f 'u FROM AMBEKI-YST A - 2 b ( M D COLUMN(BED-VOLUME : 2 L I T R E S ) .
89
fitted with * 800 mi of Amberlite XE-270 resin was incorporated
in series to the Amberlyst A-26 column after the 1st run. The
effluent from the 1st column passed through the second column
at the same rate and the concentration of plutonium in the
effluent of second column was low enough to permit their direct
disposal. During the elution, these two columns were
disconnected and plutonium from each column was eluted
separately. Dilute plutonium solution', in the tailing part of
these columns were used as the eluant in subsequent runs to get
as much concentrated plutonium as possible which will be useful
for the subsequent oxalate precipitations.
From the results of all the six runs, the following
observations could be made.
Inspite of channelling observed in all the runs, by careful
control, loss of significant amounts of Pu in the
effluents could be prevented.
Capacity of the Amberlyst A-26 resin for plutonium loadi 1^
remained nearly the same inspite of repeated use.
Elution characteristics were also retained by this resin
after repeated use.
Resultant concentration of plutonium in the first two beJ
volumes of each run were high enough (> 30 g Pu/litre)
for direct precipitation of Pu(IV) oxalate.
Elution data of all the six runs are summarised In
Table -36. Thus, the entire plutonium in HC1 medium receivesd
from RMD was processed as detailed above. The set-up and
operations which was more or less 1 ike a plant run, was
continued In a single glove box. This successful operation has
shown for the first time the feasibility of anion exchange
recovery and purification of plutonium in large quantities
using a macroporous anion exchange resin Amberlyst A-26.
90
References.1. V.V.Ramakrighna and S.K.Patil, Paper IT-4, Radiochemistry and Radiation
Chemistry Symposium,Bombay,Feb.19882. L. Drummand and R.A. Grant, Talanta, 13., 477 (1966 ).
Table - 36
ELUTION DATA FOR AMBERLYST A-26 IMP) RESIN RUNS,BED VOLUME 2 LITRES
BED VOLUME
FORECUT
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
Volumedit)
XPu eluted
Volumedit)
XPu eluted
Volumedit)
XPu eluted
Volumedit)
XPu eluted
Volumedit)
XPu eluted
Volume!1 it)
XPu eluted
Volumedit)
XPu eluted
10
244(44,
2.52.(97.
0.1.
(99.
2.0.
(99.
1.0.
1
.2
.33
.0
.29
.62)
.05,82,44)
,79337)
05592)
7508
(1001
RUN No.
11
245(46
248(94.
2.3,
(98.
2.1.
(99.
2.0.
(99.
2.0.
2
.3
.32
.0
.01
.33)
.0
.54
.87)
.0
.35,82)
01638)
05189)
011
(100)
10
248(49
2,47.
(96,
0.2.
(98.
2.1.
(99.
2.0.
(99.
2.0.
3
.5
.29
.0
.96
.25)
.0
. 34,59)
,5,0261)
01172)
02496)
004
(100)
10
227(28
23"(67,
2,30,(98.
2.1.
(99.
2.0.
(99.
2.0.
4
. 4
.36
.0
.65
.01)
.0
.25)
,0.00.05)
05661)
02788!
012
(100)
5
1.20.43
2.042.e8(43.31)
2.0
(86.54)
2.011.42(97.96)
2.01.06
(99.02)
2.00.50
(99.52)
2.00.48
( 100)
10
239(39
24 i),
(88,
2.9.
197.
2.1.
(99.
2.0.
(99.
2.0.
6
.5
.05
.0
.30
.35)
.0
. 18
.53)
.022,751
04823)
04972)
028
(100)
Figures in brackets refer to cumulative X of plutonium eluted.
91
2.3.3. STUDIES ON THE RECOVERY OF U-233 FROM PHOSPHATE
CONTAINING AQUEOUS WASTE USING DBDECMP AS EXTRACTANT.
V.B. Sagar, M.S. Oak, S.M. Pawar, C.K. Sivaramakrishnan
and S.K. Patil.
2.3.3.1. 1 introduction
Uranium-233 bearing nuclear fuels are routinely analysed for
their uranium content by Davies & Gray method '*'. The
analytical waste generated, contains phosphoric acid alongwith
metallic impurities such as Fe, V, Mo etc. Uranium-233 being a
valuable fissile material, it has to be recovered from such
wastes for recycling. Conventional methods, such as TBP
extraction or anion exchange can not be used for recovery
of U-233 from such solution.
During the last few years, various neutral bifunctional
organophosphorus compounds have been synthesized'2) and some
of their physical and chemical properties have been
characterized. Schulz and Me 1 ssac^" 6 ̂ following an earlier
suggestion of Siddall'-^ demonstrated that certain neutral
bifunctional organophosphorus reagents are particularly
suitable for removal and recovery of actinide ions from various
highly acidic nuclear fuel cycle waste solutions.
Recently the CMP group of compounds (dialkyl N,N-diethyl-
carbamoyl- methyl phosphonates) are being explored for their
suitablity as the extractants for actinides [ 8 ]. The extraction
of selected transplutoniurn (III) and lanthanide (III) ions
and of Th(IV) and U(V I ) from aqueous nitrate media by DHDECMP
(Di-hexyJ N, N diethyl carbamoyImethyI phosphonate) has ben
reported t9.10]. x n e extraction of AmlNl), Pu(lV) and U(V1)
by DBDECMP from aqueous nitric acid solutions haa also been
92
reported ^ 11 ] .
Present work describes the use of DBDECMP for the extraction of
Uranium(VI) with a view to develop a method for the recovery of
U from an analytical waste containing HNO3, H2SO4 and H3PO4 .
2.3.3.2 Exper imental
Materials:
Uranium-233 was purified by anion-exchange from chloride
medium,fo11 owed by TBP-extraction method. The radiochemica1
purity of U-233 was then ascertained by alpha spectrometry
using a silicon surface barrier detector coupled with a 4K
analyzer. DBDECMP was obtained as 99% pure compound from
Columbia Organic Chemicals Co. Inc. Camden, SC.USA and was used
as such. All other chemicals used were of A.R. Grade.
Procedure:
Stock solutions of known concentrations of HNO3, H2SO4
and H3PO4, were prepared by dilution of concentrated acids and
standardizing them by tirating with standard NaOH solution.
DBDECMP solution of desired concentration was prepared by
diluting measured volume with xylene. Uranium-233 stock
solution was prepared in 1M HNO3 .
Extraction experiments with U-233 (VI):
5 ml each of aqueous solution of desired composition
containing «* 5 ng/ml of U-233 (VI) and DBDECMP solution in
xylene (unequi1ibrated) were pipetted in ground glass stoppered
tubes. The tubes were equilibrated for 30 minutes using a
mechanical shaker at 25°C(±0. 1°C ) . At the end of
equilibration, the phases were allowed to settle and
appropriate aliquots from both the phases were withdrawn to
measure the U-233 concentration radlometrleally. The
93
concentrations of U-233 in both the phases were determined
by alpha- liquid scintillation counting using a dioxane based
scinti11ator.
Extraction of U-233 from analytical waste.
The analytical waste produced during Davies and Gray method has
an approximate composition: HNO3-O.5M + H2SO4-IM + H3PO4-3M,
U-233 0.2 - 0.4 rag/ml, Fe 2mg/ml, Mo 0.15mg/ml. It was
adjusted in HNO3 concentration to 5M by adding appropriate
amount of concentrated HNO3. 100 ml of this aqueous feed
solution, with approximate composition H2SO4 - 0.5M, H3PO4 - 1M
and HNO3 - 5M, was contacted 3 times with 50 ml of 30%
DBDECMP-xylene (Preequi1ibrated with 8M HNO3) each time. 150 ml
of the organic phase was collected together and washed twice
with 50 ml of distilled water each time to remove the
extracted nitric acid. Uranium-233, from this organic extract
was back-extracted with 100 ml of 1M!NH4)2CO3 . Initial and
final concentration of U-233 was determined by alpha-liquid
scintillation counting. The concentration of the impurities was
assayed by spectroscopic methods.
Extraction of impurities.
A synthetic mixture of U, Fe, V and Mo was prepared in an acid
mixture of 0.5M H 2S0 4 + 1M H 3P0 4 + 5M HN03 . The
concentrations of these metal ions were in the same range as
expected in the actual analytical waste. The extractions,
washings and the back extractions were carried out following
the same prjcedure as is described above. The extraction
studies were carried out in the presence and in the absence of
uranium. The analysis of the impurities was carried out by
spectroscopic methods.
94
Absorption spectral studies.
Milligram amounts of natural U(V1) were extracted into 30%
DBDECMP- xylene from 5M HNO3 and also from an acid mixture
containing 0.5M H2SO4 + 1M H3PO4 + 5M HNO 3 . The spectra of
the organic extracts containing U(VI) were recorded on a
Beckman Du-7 recording spectrophotometer using the respective
organic solutions preequi1ibrated with the corresponding
aqueous phase without U < V I ) as blanks, with 1 cm path length
quartz cell.
2.3.3.3 Results and Discussion.
Distribution ratio of I) (V1 ) from various aqueous media:
The data obtained on the extraction of U(VI) by 10% DBDECMP-
xylene from varying concentrations of nitric acid (0.5M to 5M)
are given in Table - 37. It is seen that the distribution
ratio of U(VI) increases with nitric acid concentration and
U(V I ) is almost quantitatively extracted when the nitric acid
concentration is 2 3M. The data obtained for the extraction of
U(VI) from an aqueous phase containing 2M HNO3 + varying
concentrations of H2SO4 ( . 25M to 2M) are included in Table -37.
It is seen that the extraction decreases with increase in H2SO4
concentration. This may be attributed to stronger complexing
of U(VI) with sulphate. The data obtained on the extraction
from 0.5M H2SO4 varying concentrations of HN03(0.5 to 5M) are
also included in Table - 37, which show that the extraction of
U(V1) can be enhanced by increasing the HNO3 concentration of
the aqueous medium. The data were also obtained for the
extraction of U(VI) from 0.5M H 2 S 0 4 + 3M HNO3 + Varying
concentrations of H3PO4 (Table - 3 8 ) , which show a further
decrease in the extraction of U with increasing H3PO4
concentration. This again may be attributed to stronger
complexing of U(V1) with phosphate. In order to optimise the
conditions for the quantitative extraction of U ( v11 ) from a
95
mixture of H2SO4 , H3PO4 and HNO3 , D values of U ( V I )
were determined from an aqueous medium containing
0.5M H2SO4 + 1M H3PO4 + HNO3 concentration varying from 1M to
5M. The data obtained are also listed in Table - 38 and these
indicate ~ 50% extraction of U(VI) from 4M and above with 10%
DBDECMP - xylene.By increasing the concentration of DBDECMP toe,
30% and by resorting to multiple extration, if required, it was
felt that U(VI) could be quantitatively extracted.
Extraction of U-233 from actual analytical waste.
The approximate composition of the actual analytical waste
produced during Davies and Gray method is mentioned earlier.
HNO3 concentration was adjusted to 5M by addition of
concentrated HNO3 before extraction of U-233. Results of the
recovery of U-233 from the adjusted analytical waste are
presented in Table - 39. It is seen that "95% of U-233 is
recovered by this method.
Extraction of impurities.
Fe, V and Mo are the major impurities introduced in the system
during the analysis. The extraction of these impurities by
using the above extraction procedure was investigated to find
out the decontamination achievable for uranium. For this, the
extraction of Fe, V and Mo from a synthetic mixture was studied
in the presence and in the absence of U(V1) and also from the
analytical waste generated. From the organic extracts,
Fe,V,and Mo were back-extracted and their concentrations were
measured by spectroscopic method. It was observed that the
decontamination factor for Fe and Mo was better than 10 and
that for V was 25. It can therefore, be inferred that by
using the present method, U-233 can be recovered and purified
from the impurities present.
96
A b s o r p t i o n s p e c t r a l s t u d i e s :
A b s o r p t i o n s p e c t r a of t h e o r g a n i c e x t r a c t s of U ( V 1 ) e x t r a c t e d
f r o m 5M H N 0 3 a n d f r o m 5M HNO3 + 0 . 5 M H 2 S n 4 + 1M H3PO4 w e r e
r e c o r d e d a n d a r e c o m p a r e d i n F i g 9 . T h e a b s o r p t i o n s p e c t r a a r e
i d e n t i c a l w i t h r e s p e c t t o a b s o r p t i o n m a x i m a a s w e l 1 a s m o l a r
a b s o r p t i o n c o e f f i c i e n t s ( 3 9 a n d 3 8 r e s p e c t i v e l y f o r e x t r a c t i o n
f r o m 5M H N 0 3 a n d f r o m 5M HNO3 + 0 . 5 M H 2 S 0 4 + 1M H3PO4 )
i n d i c a t i n g t h a t t h e U ( V I ) s p e c i e s e x t r a c t e d f r o m t h e a c i d
m i x t u r e i s p r o b a b l y t h e s a m e a s t h e o n e e x t r a c t e d f r o m o n l y
n i t r i c a c i d . S p e c t r a a r e a l s o i d e n t i c a l w i t h t h a t r e p o r t e d i n
t h e 1 i t e r a t u r e ^ " . H e n c e i t c a n b e i n f e r r e d t h a t o n l y
U 0 2 < N 0 3 ) 2 . 2 D B D E C M P i s t h e s p e c i e s of U ( V 1 ) e x t r a c t e d e v e n f r o m
a q u e o u s m e d i u m c o n t a i n i n g a m i x t u r e of H2SO4 , H 3 P O 4 a n d HNO3 .
R e f e r e n c e s
1. W. Dav ies and U. Gray, Ta 1 a n t a , H_, 1203(1964 ) .2 . W.W. S c h u l z and J . D . N a v r a t i l Sep. Sci and Tech. 19., pp927-94 i ( 1 9 8 4 - 8 5 ) .3 . W.W. S c h u l z , U.S.ERDA Repor t ARH-SA-203, A t l a n t i c R i c h f i e l d Hanford Co,
R i c h l a n d , Washing ton , 1974.4 . W.W. Schu lz and L.D. M c l s s a c , in T r a n s p l u t o n i u m 1975 (U .Mul l e r and R.
L i n d n e r , e d s . ) Nor th H o l l a n d , Amsterdam, 1976, p . 4 3 3 .5 . U.W. S c h u l z and L.D. M c l s s a c , i n P r o c . 1SEC 77 , Canad ian i n s t . Min. Met . ,
T o r o n t o , Canada, 1978.6. L.D. M c l s s a c , J . D . Baker , and J.W. Tkachyk, U.S. ERDA Repor t ICP-1080,
A l l i e d Chemical C o . , Idaho f a l l s , Idaho. 1975.7. T.H. S i d d a l J r . , U .S . P a t e n t 3 , 243 , 254 (19661 .8. U.U. S c h u l z and J . D . N a v r a t i l , "Recent d e v e l o p m e n t s in Sep . S c i . 1 ,
V o l . V I I , Li N.N. Ed. CRC p r e s s , Boca Ra tan , F l a . , 1982 C h a p . 2 .9. t . P . H o r w i t z , D.G. K a i i n a and A.C. M u s c a t e l l o , Sep. Sci and Tech.
16_, p p 4 0 3 - 4 1 6 ( 1 9 8 1 l .10. E . P . H o r w i t z , A . C . M u s c a t e l l o , D.G. K a i i n a and L. Kaplan , Sep. S c i .
Tech. IJL.pp 4 1 7 - 4 2 6 ( 1 9 8 1 ) .11 . A.V. J a d h a v , V.K. Goyal , S.N. P a t t a n a i k , P . S . Shankaran and S.K. P a t i l ,
J . R a d i o a n a l . Nuc) . Chem., A r t i c l e s , 8 2 , 2 2 9 - 2 4 5 ( 1 9 8 4 1 .
1.0
1 : [U] =1.771 xlO M
2 : [U] • 1.592 *10"2M - 1.0
350 425
WAVELENGTH, nm
500
Fig 9. ABSORPTIONINTO 30X(1) 5M HN03
SPECTRA OP U<V I ).EXTRACTEDDBDECMP-XYLENE FROMAND (2) 0.5M H2SO4+1M H3P04+5M HNO3.
97
Table - 37
Variation of Distribution Ratio of U(VI) with Aqueous Phase CompositionOrganic Phase: 10% DBDECMP-XyIene
A B C
Aqueous phase D Aqueous phase D Aqueous phase D
0.5M HN03 2.6 2M HNO3 + 0.25M H2S04 8.1 0.5M H2S04 + 0.5M HNO3 0.8
1.0M HNO3 5.0 2M HNO3 + 0.5M H2S04 6.7 0.5M H2S04 + 1.0M HNO3 2.2
2.0M HNO3 10.8 2M HNO3 + 0.75M H2SO4 5.4 0.5M H2S04 + 2.0M HNO3 5.9
3.0M HNO3 15.9 2M KMO3 + 1.0M H2S04 4.7 0.5M H2S04 + 3.0M HN03 9.4
4.0M HNO3 21.7 2M HNO3 + 1.5M H2S04 3.8 0.5M H2SD4 + 4.0M HNO3 13
5.OH HNO3 27.2 2M HNO3 + 2.0M H2S04 2.7 0.5M H2S04 * 5.0M HNO3 17
Table - 38
Variation of Distribution Ratio of U(VI) with Aqueous Phase CompositionOrganic Phase : 10X DBDECHP - Xylene.
A B
Aqueous phase D Aqueous phase D
0.5M H2S04 +3M HNO3 +0.25M H3P04 3.8 0.5M H2SO4 U H H3P04 +1H HNO3 0.2
0.5M H2S04 +3M HNO3 +0.50(1 H3P04 2.1 0.5M l!2S04 +1M H3P04 +2M HNO3 0.6
0.5M H2S04 +3M HNO3 +0.75M H3PO4 1.3 0.5M H2S04 +1H H3PO4 +3M HNO3 0.8
0.5M H2S04 +3M HNO3 +1.0 M H3PO4 0.9 0.5M H2S04 +1M H3P04 +4M HNO3 1
0.5M H2S04 +3M HNO3 +1.5 ti H3P04 0.4 0.5M H2SO4 +1M H3P04 +5M HNO3 1.1
0.5M H2S04 +3M HNO3 +2.0 M.H3PO4 0.3
98
Table - 39
Extraction of U-233 from analytical waste generated during Davies and Gray
method:Aqueous phase - adjusted to 0.5M ^SO^.IM H3PO4 and 5M HNO3
Organic phase - 30% DBDECMP - Xylene
(Preequi1ibrated with 8M HN03)
Total U-233 taken = 13.2 rag
Unextracted U-233 = 0.27 rag i" 2%)
Loss in washings = 0.14 mg I" 1%)
Back-extracted U-233 = 12.7 mg (~ 96X)
(with (NH4>2C03 solution)
99
3. CHEMICAL QUALITY CONTROL OF NUCLEAR FUELS.
3.1 ANALYTICAL METHODS
3.1.1 DISSOLUTION OF Pu-Al-Zr ALLOY FOR THE POTENT IO11ETR IC
DETERMINATION OF PLUTONIUM
R.B. Manolkar, S.P. Hasilkar, Keshav Chander and
S.G.Marathe
Accurate knowledge of plutonium in Pu-Al-Zr alloy becomes
necessary in its fabrication. Known methods C1.23 of
.dissolution employ either 6M HC1 or HNO3 containing Hg(II) in
trace amounts. Solutions obtained by these methods cannot be
directly used for the potentiometric determination of plutonium
using AgO oxidants^ 3 3. Therefore a method has been developed
for the dissolution of Pu-Al-2r alloy that could be directly
employed for the determination of plutonium.
Various reagents like Cone. HNO3, Conc.H 2S0 4, HCIO4, Conc.H 2S04
-1M HNO3 etc. were tried for dissolution. HCIO4 and cone.
H2SO4-IM HNO3 gave clear solutions but the latter was preferred
for the dissolution of the samples as this does not involve the
heating step and the use of hazardous HCIO4 is avoided. The
presence of concentrated H2SO4 not only provides the heat of
dilution but also prevents the formation of the oxide layer.
The alloy samples (200-300 mg) were dissolved in concentrated
H2SO4- 1M HNO3 as well as in conventionally employed 6M HCl
also. The solutions obtained by dissolution in 6M HCl were
fumed with concentrated H2SO4 in order to remove the chloride
ion prior to the plutonium determination. The results are
given in Table - 40 for comparison sake. It can be seen that
100
the results obtained by cone. H2SO4-IM HNO3 dissolution are in
good agreement (within ± 0.4%) in comparison to those obtained
by 6M HC1 dissolution method. This method of dissolution was
employed for the determination of plutonivim in Pu-Al-Zr alloy
fuel samples during fabrication campaigns.
References:
1. O.J. Wick Ed. "Plutonium Hand-Book", 2,728(1980)
2. W.W. Schulz, BNWL-204 (1966).
3. J. L. Drummond and R.A. Grant, Talanta, JJ3 ,477(1966).
Table - 40
Comparison of Pu-values in the alloy Pu-Zr-Al using the
present and conventional methods of dissolution.
SI. No. % Plutonium dissolution in % Deviation
SM HC! Present Method
1 38.41 ± 0.02
2 39.39 ± 0.03
3 38.71 ± 0.08
4 38.31 ± 0.01
5 23.09 ± 0.03
6 23.51 ± 0.01
38.56 ± 0.05
39.35 ± 0.01
38.69 ± 0.01
38.43 ± 0.02
23.09 ± 0.04
23.54 ± 0.02
+ 0. 39
-0. 10
-0.05
+ 0.31
+ 0.01
+ 0. 13
101
3.1.2 ELECTROCHEMICAL METHODS
3.1.2.1 COULOMETRtC DETERMINATION OF URANIUM BY SUCCESSIVE
ADDITIONS METHOD
N. Gopinath, J.V. Kamat, H.S. Sharma, S.G. Marathe and
H.C. Jain
The successive addition method involves the analysis of new
aliquot added successively to the same electrolyte medium
containing previously analysed aliquots. Main advantages of
this method are the reduction in analytical waste volume and
also in overall analysis time. Efforts were, therefore, made
for developing this method for uraniun determination in UO.?.'
UN, UC type fuels. During the course of this study, 10-12
aliquots of a. solution were analysed for uranium and the
accuracy 'and precision of better than ± 0.2% was achieved. it
may be emphasised that only 20ml of analytical waste was
generated including washings after analysis of 10 aliquots
while by the conventional coulometric and potentiomet.i.-
methods the volume of waste is normal ly 100 and 30Cir.!
respectively. Results of uranium analysis by this method are
presented in Table - 41.
The influence of time delay on the analytical value of uranium
in a fresh aliquot analysed in the same electrolyte containing
uranium!(VI, accumulated from previously analysed ai'quots. was
also investigated.
The values were found to be positively biased and the bias
increased with time delay (03% for 30 minutes,0.6% for 60
minutes and 1.6% for 90 minutes) but decreased with the
increase in sulphuric acid concentration. On the basis oi
102
studies carried out, the positive bias was attributed to the
oxidation of U( IV) by mercurous ions produced in the
coulometric cell by dissolution of mercury in electrolyte
medium. The positive bias could be eliminated when the
electrolyte containing small amount of uranium <VI) was re-
electrolysed at -0.320 V Vs SCE after delayed interval prior to
the addition of a fresh aliquot for analysis. This
particular observation shall be useful for the analyst whan
aliquots are likely to be analysed at delayed intervals.
Results of uranium analyses at delayed intervals are glvan in
Table -42.
Table - 41
Results of U analysis by successive addition Method in H2SO4(U-Content per aliquot : 3 to 4 ag>
No. of Total U Analysis Total waste(H2SD4] determi- accumulated Tiae voluae generated R.S.D
M nations (rag) (ain) lal) X
0.1
0.1
0.1
0.1
0.5
1
2
3
6
6
13
8
20.18
22.05
35.89
24.03
72
75
150
100
6
6
9
7
103
Table - 42
Uraniumelapsed
[H2S04]
0.5
1.0
2.0
3.0
analystime
is byinterval
U, Expected
mg/g
16.70
16.70
16.70
35.72
successivefol1 owed
30
16.
16.
35.
by
u,
rain
,70
72
68
additions methodre-electrolysis.
Determined mg/g
60
16,
16.
16.
35.
min
,75
69
71
69
90
-
16
16
35
after the
min
.72
.72
.71
104
3.1.2.2 CONTROLLED POTENTIAL COULOMETRIC DETERMINATION OF
URANIUM IN PRESENCE OF IRON OR PLUTONIUM USING
PLATINUM WORKING ELECTRODE
U.M.Kasar,A.R.Joshi,C.K.Sivaramakrishnan and S.K.Patil
Coulometric determination of uranium is conventionally carried
out using mercury electrode. Use of mercury as working
electrode requires critical control over purity of mercury,
stirring conditions and purity of inert atmosphere during the
determination of uranium. Use of solid working electrodes
minimises some of these difficulties. Moreover by using solid
electrode in gauze form, larger surface area of the working
electrode can be easily achieved and unlike mercury electrode
it can be maintained constant during the electrolysis without
much difficulty. Philips and Grossley'-l^ have reported a
controlled potential coulometric method for the determination
of uranium using solid working electrode. In their method
uranium is chemically reduced to U(IV) by eIectrolytical1y
generated hydrogen and U(IV) thus produced is determined by
electrolytic oxidation at platinum working electrode using
Fe(III) as an intermediate. Fardon and McGowan^] have used
Ti(lll) for chemical reduction of U(VI ) and U(IV) thus produced
is oxidised at gold working electrode. Interferences from iron
or plutonium in the above methods were overcome by the
determination of both U+Fe or U+Pu by simultaneous oxidation in
the first electrolysis step followed by the determination of
only iron or plutonium in subsequent reduction step. The amount
of uranium in such samples is computed from the difference in
the charge collected in the two electrolysis steps.
The major disadvantage in these methods is that they give rise
to large errors in uranium values particularly when iron or
plutonium is present in large quantities. An alternate method
was,therefore, developed for the determination of uranium in
105
presence of large quantities of iron or plutonium in which
consideration was given to selective oxidation of Fe(II) or
Pu(lII) prior to determination of U(IV) to reduce time and
errors in the analysis.
Analytical procedure.
The method consists of reduction of uranium and iron or
plutonium in the aliquot to U(fV) and Fe(II) or Pu(III) in
8-9 fi H2SO4 by Tit 111). The destruction of excess Tit I N ) and
the selective oxidation of Fe(Il) or Put II I) was carried out by
adding a few drops of 7-8 M HNO3 followed by addition of a few
drops of 1.5 M sulfamic acid within 10-15 seconds after nitric
acid addition. Uranium (IV) was then oxidised e1ectro1yticaI 1y
at 0.75 V vs SCE after diluting the solution to 2-3 M H 2 S 0 4
and adding 4-5 mg of Fe( I I I I. The charge collected in this
electrolysis step was used to calculate the amount of uranium
in the aliquot.
Results.
The method was employed for the determination of uranium in
pure uranyl sulphate solution and the results obtained are
summarised in Table - 43. During the application of this method
for the determination of uranium in presence of iron or
plutonium, it was observed that after destruction of excess
Ti(III) and selective oxidation of Fe(ll) or Pu(lII) by
7-8 M HNO3, sulfamic acid must be added within 10-15 seconds.
The time delay in the addition of sulfamic acid can result in
catalytic oxidation of U(1V) by iron or plutonium giving lower
values for uranium. The results obtained on the determination
of uranium in the synthetic mixtures of U+Fe and U+Pu at
varying ratios of U/Fe and U/Pu a:e summarised in Tables 44 and
45 respectively. It was observed from the results that the
method gives reproducibi1ity of < ± 0.25% and the uranium
values are in excel lent agreement with corresponding values
106
o b t a i n e d u s ing Davies and Gray
Reference.
1. G. Phillips and D. Grossley, Proc. of Int. Symp. on Nuclear materialssafeguards, IAEA, Vienna, 1978, IAEA -SM-231/56.
2. J.B. Fardon and I.R. McGowan, Talanta,1£, 132K1972).3. W. Davies and V. Gray, Talanta,n,120311964).
Table - 43
Determination of uranium in pure urany1 sulphate solutions.
5.No.
1.2.3.4.5.6.7.8.9.
10.11.12.13.14.15.16.17.18.19.20. .
Mean = 32.98 mg/gR.S.D. = ± 0.2%
Concentration determined by Davies and Gray method = 32.95 mg/g
Amount of uranium<mg)
4.0074.7837.9824.3394.1564.9035.0524.8844.0084.9903.7814.1975.0493.2453.8943.3523.5003.4643.2083.552
Concentration of uranium(mg/g)
32.8832.9832.9033.0332.9032.9432.9032.9333.0732.8533.0932.9933.0832.9933.0232.9832.9733.0532.9733.03
107
Table - 44
Determination of uranium in presence of varying amounts of Iron.
S.No. U/Fe ratio Concentration of R.S.D.uranium mg/g '%
1. 10 : 1 32.94 (11) ± 0.18
2. 6 : 1 32.96 (10) ± 0.23
3. 4 : 1 32.97 (11) ± 0.20
4. 2 : 1 32.93 (12) ± 0.21
5. 1 : 1 32.93 (10) ± 0.18
Concentration determined by
Davles and Gray method 32.95 mg/gFigures in parentheses indicate the number of determinations.
Table - 45
Determination of uranium in presence of varying amounts of plutonium
S.No. U/Pu ratio Concentration of R.S.D. * Expected cone.
uranium (mg/g) % (mg/g)
1.
2.
3.
4.
5.
6.
Pure
25
15
5
1
1
uranium
: 1
: 1
: 1
: 1
: 5
31.
176.
156.
59.
109.
109.
82
21
22
443
36
16
(4)
IE)
(5)
(6)
(6)
(8)
± 0.
+ 0.
+ 0.
± 0.
± 0.
± 0.
06
08
13
11
24
22
31
176
156
59
109
109
.87
.25
.50
.484
.41
.41
Concentration determined by Davies and Gray methodFigures in parentheses indicate the number of determinations
108
3.1.2.3 A NEW APPROACH FOR THE DETERMINATION OF URANIUM BY
CONTROLLED POTENTIAL COULOMETRY BY MAKING USE OF
COULOMBS VS TIME RELATIONSHIP
P.K. Kalsi, L.R. Sawant and S. Vaidyanathan.
In the earlier work, measurement of coulombs at particular
current intervals was made use of to calculate the total
coulombs due to the reduction of U < V I ) to U(IV).The measurement
of current manually has some uncertainty whereas time and
coulombs can be automatically recorded and stored in a
multimeter. Hence a relationship of coulombs Vs time has been
derived simplifying Lingane's equation. The equation derived
is given by
Q R = (Qoo - Q t ) = Remaining coulombs at time t^
Q R ^ = (Qoo - Qto' = Remaining coulombs at time t2
Q w = total coulombs ; Q^. = Coulomb at time tj
and Q^_ = Coulomb at time t2
This is a transcendental equation. It is solved by
computational iterative method. This method is applicable to
all reversible and irreversible ions provided they obey the
Lingane's equation. In addition to the advantages like
reduction in electrolysis time and background correction, the
present technique needs less operator's attention, since both
coulombs and time are automatically stored in the multimeter at
intervals of one minute each.Subsequent 1y, the values of Q^
1at time t± and Q t at time t2 are recalled for calculating the
2total coulombs Q. The mean value for the determination of 20
109
aliquots from the uranium stock solution was 11.71 mg/g with an
RSD of 0.14% (expected value being 11.72 mg/g).
3.1.2.4 DETERMINATION OF URANIUM BY TI(III) REDUCTION AND
BIAMPEROMETRIC TITRATION
P. R. Nair, K. V. Lohitakshan, Mary X"av ier, S. G. Marathe, and
H.C. Jain
A novel method for the determination of uranium in presence of
iron by Til III) reduction was reported earl ier'-^, During the
period of this report, further studies on the fo!lowing aspects
were carried out:
Determination of uranium in presence of Plutonium
Studies on uranium determination in presence of plutonium have
shown that the method works satisfactorily. Pu(tll) formed
during the reduction by Til III), gets selectively oxidised by
HNO2 generated during Tit 111) destruction, in the same way as
Fe(11), and does not cause any interference. The amount of
uranium per aliquot was varied from 1 mg to 7 mg and plutonium
from 1 mg to 3 mg. The proportion of plutonium in the samples
varied from 20-70%. Satisfactory results are obtained when the
amount of plutonium per aliquot is kept below 4mg. There is a
tendency for negative bias when the plutonium amount exceeds
4mg. This may be due to the increasing prominence of the
reaction between U(1V) and Pu(lV) giving rise to Pu(lll) before
the destruction of the excess HNO2. This results in
oxidation of Pu(III) by HNO2 instead of dichromate. As
long as the amount of plutonium is less than 4mg
there is no detectable bias. The precision of 37
determinations was jetter than 0.2 percent as can be seen
110
from Table - 46. The method thus can be adopted
oxide, mixed carbide or mixed nitride samples.
for mixed
S.No.
Table - 46
Determination of U in presence of Pu by Till 11) reduction
No. ofdetmns.
Pu-range(X) (rag>
U-range<mg)
U conelmg/g)
RSD Devi.(X)
123456
668881
20-3031-4041-5051-6061-7071-80
(77)
1-31-31-21-72-3.12 . 9
2.4-7.2.4-6.
1-30.8-4.1.2-1.0.85
24
75
13.82613.80713.83313.81613.81413.818
0.130.. 120.130, 130.17
-
+0.01-0.13+0.06-0.07-0.08-0.05
Expected U Cone.=13.825 mg/g;0veralI mean value for 37 detmns.=13.819 mg/goverall RSD = 0.15% Deviation = -0.04%
Ill
Determination of uranium at microgram levels.
The accuracy and precision of the method for microgram amounts
of uranium was evaluated using uranium standard solution. At
BQOng, 3OOj4g, lOOjjg and 50>ig levels, the respective precisions
were 0.25%, 0.43X, 0.8% and 0.9%. A few experiments were also
carried out in the presence of plutonium. The percentage of
plutonium in these aliquots varied from 73%-94% and the
uranium amounts varied in the range of 100pg-500>jg. The overall
precision was 0.4% from 11 determinations as shown in
Table -47. As the method works satisfactorily for ng amounts
of uranium in presence of plutonium, it is worth testing its
feasibility for determination of uranium in dissolver
so Iut ions.
Effect of foreign ions.
The effects of chloride, sulphate, fluoride, oxalic acid,
mellitic acid, Pd, Ru and Al were studied. Large amounts of
chloride and sulphate do not have any effect. Also the
presence of other ions 300>ig of F, 20mg of Al, 200ug of Pd,
50>jg of Ru did not affect the results. Mellitic acid did not
have any effect even when present at lmg level while oxalic
acid gave a positive bias.
1 1 2
Tab le - 47
D e t e r m i n a t i o n of U in microgram l e v e l s in p r e s e n c e of Pu by T i ( I I l )r e d u c t i o n method
S. No.
1234567891011
PIutoniumrag <
1.901.631.481.551.451.591.511.581.521.571.55
(X)
73737374737584858593.593.6
U rani urnrag
0.7090.5950.5380.5330.5230.5240.2760.2760.2620. 1100. 106
mg/g
1.2811.2871.2811.2841.2761.2831.2921.2911.2791.2801.287
Mean Value = 1.284 mg/g; RSD = 0.39% Expec ted v a l u e = 1.282 mg/g
R e f e r e n c e .
1. FCD Annual Report,1987.
3. 1.3 TfTRIMETRIC METHODS
3.1.3.1 EFFECT OF AgO AND EDTA ON Fe( I I )/K 2Cr 20 7 T1TRAT10N FOR
THE DETERMINATION OF PLUTONIUM
S.P. Hasilkar, Keshav Chander and S.G. Marathe
Requisite concentrations of thorium and plutonium are among
the important specifications for thorium-plutonium oxide which
is a potential fuel for the future generation reactors and an
accurate knowledge of these becomes essential. The dissolution
of ThO2~PuO2 can be carried out in HNO3-HF mixture of
appropriate compositon. The determination of thorium in
presence of plutonium can be done by complexometric titration
113
with standard ethy1enediamine tetraacetic acid (EDTA) solution
and that of plutonium by AgO-oxidation method. These
determinations have to be carried out in separate aliquots.
Experiments in our laboratory, in connection with sequential
determination of plutonium by AgO-oxidation method following
the determination of thorium, gave irreproducib1e and higher
values of plutonium. With a view to understand the role of
various reagents, which can possibly affect the determination
of plutonium, systematic investigations were carried out and
the details are given here.
Effect of AgQ
The results of the studies on the effect of varying amounts of
AgO on Fe(1 I)/K2Cr207 titre value (amount of K2Cr 2O 7 solution
equivalent to Ig Fe<ll) solution) are given in Table - 48. It
can be seen from the Table that the dichromate titre value
goes on decreasing with increasing amounts of AgO. It is
lowered to the extent of 1.5% When 200mg AgO is added. The
lowering may be either due to some Ag( I 1) left undestroyed by
sulphamic acid but subsequently getting reduced by Fe(II) or a
fraction of Ag(I) ions getting further reduced by Fe<[[) to
metallic silver Ag(O). Investigations carried out in our
laboratory to look into these aspects revealed that only
when sulphamic acid is used for the destruction of AgO, the
titre value is lowered. This indicates that either Ag(II) does
not get quantitatively reduced to Ag(I) by sulphamic acid or a
fraction of it gets bound in the form of some complex with
Ag( I I ).
Further experiments were carried out using various amounts of
sulphamic acid for the same amount of AgO (200mg). It can be
seen from Table 49 that there is a steady increase of negative
bias in the titre value when more quantity of sulphamic acid
is added. In fact/ reverse would be expected as Ag(Il) should
114
be destroyed more effectively with increasing amount of
sulphamic acid. These observations suggest the formation of
Ag! I I) -sulphamic acid complex. Incidental ly it was observed
that by allowing some time interval between sulphamic acid
addition and start of the titration, the bias decreased and
practically vanished after 90 minutes (Table 50). This shows
that complex formed is not stable in the medium of titration.
Effect of EDTA
Effect of varying amounts of EDTA (0.05M) was studied on
Fe( I I )/K2Cr20"7 titre value. A positive bias was observed in
the titre value and was found to increase with increase in
EDTA amount added. It exceeded even 4% for 15mg of EDTA.
Effect of EDTA on Fe! I I )/KzCrz0y titre value in
presence of AgO (200mg) was also studied. Known amount of EDTA
(equivalent to that required for the determination of 5-10mg
Th) was taken in 1M H2SO4 AgO was added and excess of it was
destroyed by sulphamic acid. Known amount of Fe(Il) was added
and it was titrated against standard K ^ C ^ O ^ . The titre value
was lower by 1-1.5% than expected which is similar to the one
obtained when only 200mg AgO was involved. Fuming with HCIO4
eliminated the bias and the results for plutonium are
reproducible, but this may not be a practical approach as
large volume of solution is needed for the treatment with
HCIO4.
The results of these studies show that many complexities are
involved when EDTA, AgO, sulfamic acid etc. are present in the
titration system. The presence of oppositely acting parameters
in varying amounts coupled with the unstable nature of complex
species leads to inconsistent values in the FeI 1 I )-K2CT207
redox reaction making a precise sequential determination of
115
Table - 48
Effect of AgO on the Fet(Medium 1M H 2S0 4
titre value0.4M HN03)
S.No. AgO added<mg)
DichromateExpected
Titre valueobtained
Dev iation
12345
02575150200
1.5101.5101.5101.5101.510
1.5101.5091.5021.4971.490
-- 0.07- 0.53- 0.86- 1.32
Table - 49
Effect of varying amounts of sulphuric acid on the Fe( I 1 ) /K-?Cr?07 titre valu-.(Medium : 1M H 2S0 4 + 0.4M HNO3 + 200rag T
S.No.
123
Su1phamicAcidt1.5M)
(ml )
3.06.010.0
Dichromateexpected
1.7841.7841.784
Table -
t
50
itre valueobtained
1.7641.7b31.747
Dev iat i on(%)
-1. 12-1.74-2.03
Effect of time of analysis on the Fe(1 I)/I^Cr^Oy titre valueIHedium : 1M H 2SO 4 • 0.4M HNO3 + 200mg AgO)
S.No.
1•c
34
T i me (min. I
52590180
Dichromateexpected
1.5981.5981.5981.590
Titre valueobtai ned
1.5691.5861.5961.598
Dev iat i onit)
-1.81-0.63-0. 13-
116
3 . 1 . 3 . 2 D E T E R M I N A T I O N OF N I T R O G E N IN URANIUM N I T R I D E
M I C R O S P H E R E S .
H . R . M h a t r e , M . A . M a h a j a n , R . K . R a s t o j> i , N . K . C h a u d h u r i .
C . K . S i v a r a m a k r i s h n a n a n d S . K . ['at il
in c o n t i n u a t i o n w i t h t h e s t u d y o n t h e a n a l y s i s of n i t r o g e n i n
u r a n i u m n i t r i d e s a m p l e s i t w a s o b s e r v e d thi't r-:p;ne m o n o n i t r i d e
m i c r o s p h e r e s a m p l e s o b t a i n e d f r o m f u p l tlcvc i opnuMit. s p o t i o n w e r e
s u s c e p t i b l e t o o x i d a t i o n . T h e s u l p h u r i c a c i d - c c p p i - r s e ' e n a t e
m e t h o d r e c o m m e n d e d f o r d i s s o l u t i o n cf r. i t r i d e : * b v
M i l n e r e t a 1 ̂ * •* g a v e l o w r e c o v o r / c f t, i * r o f c;\l z ' . A d d i t i c n
o f f e r r i c s u l p h a t e , m e r c u r i c s u l p h a t e , h y d r o g e n p R r r. >: i d e e t c .
i n 6 M H 2 S O 4 e n h a n c e d t h e r a t e o f d i s s o l u t i o n b u t t h e r e c o v e r y
o f n i t r o g e n w a s l e s s . P h o s p h o r i c a c i d w a s f:.u:id ::. u i t a b l e f u r
t h e s e s a m p l e s . A b o u t 5 0 nig o f t h e s n m p i e w .-•<?• r a f l u x e d w i t h
a b o u t 3 m l o f c o n c e n t r a t e d p h o s p h o r i c a c i d r:Mxr?rj w i t h 1 ml o f
w a t e r . T h e s a m p l e d i s s o l v e d w i t h i n 2 !..-.ui-. A d u l t ; or. o f a f e w
d r o p s o f w a t e r w a s n e c e s s a r y a s yi.ii°rwis'.' cu rci?n t r 3 f i. •)
p h o s p h o r i c a c i d ( 8 5 % ) a t t a c k e d t h e gl;i';s V P S T P ! ;ri r s f l u x i n g
a n d p r o d u c e d a s o l i d f i r m l y £>(.ihKjr i n g wir^:-,.
A f t e r d i s u ' o l u t i u n t h y :; > 1 i!i ;.:..• w ;i ̂ ( 1 ..; 1 s , • . : • •'. !. 1 • .1 ;- •. : i ;' i e ri
K . e l d a h l a p p a r a t u s , 1 5 ::i I o f c c n c c n I rct * t.'d N^l'l' W T T - , a d d ^ i i a n d
t h e d i s t i l l e d a m m e n i a w ; < s c o i l e c t n d . r. 'i% P o r i c a c i d s o l u t i o n
w h i c h w a s s u b s e q u e n t l y t i I r a L f ? d w •. '. ; •.' .1 r. :'•< 1 • i '••"! ; •_. i;-, 5 i : i c t ! i y i
r e d - b r o n i o c r e s o 1 g r p y n m i >s u • I I I K ) : - H ! 1. r . i > . n j r a n i u i n n i t r i d e
s a m p l e ( C N - 1 3 ) f r o m P i i o i L.'.v -• e 1 1 p : !• ; i t :."•>'<:( i 1 i- >:•-•••. ••'', a n a l y s i s
o f N - c o n ter, t 5 . 1 7 p e r c e n t w i t h a s t a n d a r d d e v i a t i o.-, o f ± 0 . 0 7
i . e . 1 . 4 % i n 1 7 d e t e r m i n a t i o n s . T h e d i s s o l u t i o n tin-.' v.as m u c h
l e s s w h e n t h e s a m p l e w a s p o w d e r e d . B u t t h e s a m p l e g r o u n d it;
a i r a t m o s p h e r e g a v e l o w r e c o v e r y s u g g e s t i m j l o s s o f n i t r o g e n b y
o x i d a t i o n i n a i r . It w a s a l s o o b s e r v e d t h a t a d d i t i o n o f 1 d r o p
o f 1 0 % H F in t h e d i s s o l u t i o n m i x t u r e e n h a n c e d t h > r a t e o f
117
dissolution but led to 4-5% low recovery of ammonia after
disti1lation.
References.
1. G.W.C. Milner, G. Jones, D. Crossley and G. Phillips.,AERE-R 4713<1964).
2. M.A. Mahajan, H.R. Mhatre, R.K. Rastogi, N.K. Chaudhuri andS.K. Patilj Ann. Report of Fuel Chemistry Division, 1987.
3.1.4 MASS SPECTROMETRIC METHODS
3.1.4.1 SPARK SOURCE MASS SPECTROMETRY OF MOLECULAR IONS
B.P. Datta, V. A. Raman, V.L. Sant, C.S. Subbanna and
H.C. Jain.
The ion beam produced from an r.f. spark ion source consists
mainly of monoatomic ions of all the constituent elements
(major, minor and trace) of the sample and, therefore, spark
source mass spectrometry (SSMS) is commonly employed for
elemental analysis particularly for trace analysis. The multi-
atomic ions in the beam are generally low in abundance.
However, the studies of molecular ions are important for
following reasons :
(i) for making possible an unbiased trace elemental analysis;
(ii) to explore the types of molecules formed from a spark
ion source and
(iii) for understanding the processes which could be
responsible for their formation.
The studies of molecular ions, moreover, offer an opportunity
to compare the behaviour of material in an r.f. spark ion
source with that in the equilibrium vapours at high
temperatures, thereby complementing each other.
118
A. Experimental observations, discussion and conclusions.
The studies carried out are concerned mainly with the small
molecular ions such as the carbides (MC ' ), oxides (MO ' )n n
and some other matrix-sensitive ions for a number of elements
(M) of varying electronic configurations. Tables 51 and 52
give results of the intensity distributions for some of the
carbides and oxides respectively. By and large the MC ion
abundance pattern due to different metals M falls into two
groups, namely, (1) monotonic decrease in the yields of MC
ions as n increases, and (2) a zigzag abundance distribution of
MC ions as a function of n with the maxima appearing at even
values of n. For some elements such as antimony, the
successive odd-even pairs, e.g. SbC and SbC , SbC_ and
SbC , appear to be roughly equally stable. The oxide ions,
MO , due to any given element (M) show only the decreasing
trend in yields with n and the higher oxides ( n > 3) are
generally rare. Other molecular ions,such as metal hydride(MH),
hydroxide(MOH!, ha I ide(MX ) ,cyanide IMCN), polymeric species suchas M ,M C ,M 0 , M 0 H , M X etc. were also observed. The
n m n m n m n p m n
studies show that, unless the nature of the molecular mass
spectrum for a given matrix is predetermined, the elemental
analysis may turn out to be erroneous. The details of this work
programme are given elsewhere . Factors governing the
bundance yield of molecules in the recorded ion beam and the
probable processes of their formation have been discusssed.
The transfer of material from sol id electrodes to the gaseous
plasma in a spark ion source is basically a non-thermal
process, but it resembles what is commonly known as high
temperature mass spectrometry (HTMS) in two ways :
(i) a spark ion source generates many species which are not
formed in the low temperature range and thus the former serves
as a device for crossing over the energy barriers for
reac tions; and
119
(ii) the abundance distribution of molecules such as UC ions
in SSMS parallels the abundance trend among the same series of
molecules in HTMS, thereby indicating the importance of
thermodynamic parameters of molecular ions in SSMS.
I. The abundance correction factors for molecules:
The yield distribution of M ions due to a given multi-n
isotopic element (M) and given n.
Let us consider a simple case such as the dimer molecules M_
of any bi-isotopic element M. If the two isotopes of the
element are A and B, then two types of dimers are possible,
namely, two homonuclear molecules, A_ and B_ , and a
heteronuc1 ear AB molecule. In such cases, however, it is not
explicit in the literature how the abundance corrections for
the different M molecules of given M and n were carried out.
But to know the total concentration of M molecules for given
M and nJ it is essential to apply the abundance correction. For
an element M having J number of isotopes, the abundance
distribution of M for given n, among its different probable
component molecules is expected to be governed by the
express i on
where
JJx .i i
1)
is the fractional isotopic abundance for the ith
The mass of a particular M molecule will be giveni sotope.
Jby E jm. (j<J) where m., is the mass of the ith isotope and
the multiplier j stands for the number of atoms of the ith
isotope present in the particular M molecule.
In order to verify the statistical model (Eq.l)^ the relative
120
yields of different homonuclear and heteronuc1 ear M ions of+ n
g i v e n n and p a r t i c u l a r l y t h o s e of M M i o n s , of a g i v e n m u l t i -
i s o t o p i c e l e m e n t M h a v e b e e n e s t i m a t e d for e l e v e n e l e m e n t s
u s i n g d i f f e r e n t m a t r i c e s . T y p i c a l r e s u l t s a r e g i v e n in
T a b l e - 5 3 . T h e e l e v e n e l e m e n t s a c c o r d i n g to our o b s e r v a t i o n[ 2 ]
w h i c h h a v e b e e n p r e s e n t e d in d e t a i l , c o u l d be s p l i t into two
g r o u p s , n a m e 1y,
(a) C, C l , K, S r , A g (in its own m a t r i x ) , S b , Te and B a ;
and (b) N i , Z n , M o and Ag (in s i 1 v e r - g r a p h i t e m a t r i x ) .
T h e e x p e r i m e n t a l r e s u l t s for g r o u p (a) e l e m e n t s a r e in h a r m o n y
w i t h t he s t a t i s t i c a l p r e d i c t i o n , w h i l e e x p e r i m e n t a l l y
u n a c c o u n t a b l e v a r i a t i o n s from the s t a t i s t i c a l model a r e
r e g i s t e r e d for t h e g r o u p (b) e l e m e n t s . T h e o b s e r v a t i o n s c o u l d
b e r e g a r d e d as an i s o t o p i c e f f e c t on m o l e c u l e f o r m a t i o n ;
h o w e v e r t h e r e is an u r g e n t need for a p r o p e r e x p l a n a t i o n as the
o b s e r v a t i o n s a r e n o t m a s s - d e p e n d e n t . F u r t h e r i n v e s t i g a t i o n s en
thi s line a r e in p r o g r e s s .
C . C o m p o u n d M o l e c u l e s .
T h e a b u n d a n c e s of c o m p o u n d m o l e c u l e s s u c h a s A B C , w i l l b on P q
g o v e r n e d by t h e f o l l o w i n g s t a t i s t i c a l f o r m u l a :
n P qJEx .
where x.
xK
i ii ; x ( i ) = ;
y. a n d z. a r e t h e f r a c t i o n a l ir;o t o p i c a b u n d a n c e s of
t h e i t h i s o t o p e of e l e m e n t s , A, B a m i C, h a v i n g s l o t s I of J, K
a n d L n u m b e r s of i s o t o p e s r e s p e c t i v e l y .
In f a c t , in S S M S w h e r e t h e r e is n o s t r i n g e n t r u l e f o r
i d e n t i f y i n g t h e m o l e c u l a r p e a k s , t h e c o n s i d e r a t i o n of E q . 2 in
t h i s r e g a r d is v e r y i m p o r t a n t . O u r e x p e r i e n c e s f o r i d e n t i f y i n g
t h e c o m p o u n d m o l e c u l a r p e a k s h a v e b e e n d i s c u s s e d e l s e w h e r e
121
References.1. RF-Spark source mass spectrometric studies of molecular ions.
B.P.Datta, V.I. Sant, V.A.Raman, C.S.Subbanna and H.C. Jain. Int. J.Mass Spectrora. Ion Proc, 91., 241 (1989).
2. Yield distribution of M Ions due to a given multi-isotopic element (Mland given n in the beam produced from an RF-Spark ion source.B.P. Datta and H.C. Jain. Int. J.Mass Spectrom. Ion Proc., 91,241(1989).
Table - 51
Concentrations and charge distributions of MC molecules due to differentelements Mj yield ratio of MC to MC .[ ratio of the ntegrated concentrationof MC of a given element M in the ion beam to the carbon to metal ratio inthe sample, and concentration of C molecules-
Matrix Molecule
MCn
PPMa MC / EMC / Molecule PPMn n
nMC , (C/M) (C )
n-1 n
PuO,-C
ThC-r:
Ag-C
2nO-C
NiO-C
PuCPuC2PuC3PuC,PuC3PuCtPuC7PuC8
ThCThC,ThC,ThC,ThC,ThC.
AgCAgC3AgC,
ZnCZnC,
NiCNiC,NiC,NiC,
193260523166101814
40627722074-1-1
15.0.0.
136.
1283820.
.6
.6
38534
5
3
95.699.8
9198.4
13070102
6.0.3,
0.0.
0.
0.0.0.
.5
.009
.22
.06
.8
.09
.9
.83
.0072
.7
0564
5
300515
133.7
148.7
1.83
2.9
24
c,c.c,c»c,c.c.
cac,c.c,c.c,
C»c,c«
csc,c,c,c,c,
8585107554767281031724137
122789116.11.0.0.
1894155246
10781187
2339317181
:oo
44564
a: Concentrations (parts per million) of MCn(3rd column) and Cn (8th column)with reference to M and C, respectively, in the recorded beam.
122
Table - 52
Concentrations and charge distributions of M0n to
Matrix Molecule
(non )PPMa
U30B-Ag>(3:1 bywt.)
U30.-C
(UPu)oxide-C
ThO2-C
UOUO,U03
UOUO,
UOUO,PuOPuO,
ThOThO,
1.98x10'1.6 xlO4
19
1514176
2331125951
23
9368
99.99.
95
97
9 8 .
98
8997
5
0.080.0012
0.12
0.054
0.024
0.009
a: Concentrations (parts per million) of MO n in the recorded beam,b: Matrix sparked using a power amplifier anode voltage of 4 kV.
123
Table - 53
Experimental and predicted relative abundances of Mn molecules owing to agiven multi-isotopic eleraent(M).
Matrix Element Molecule Nominal Relative yield
mass Experimental PredictedIz) from Eq.i
z/y Dev.a
ratio i%)
Graphite
KNOs-C
SrC03-C
Sb-C
Sr
Sb
C,
C,
C,,
c,.
c,,
K,C2
Sr,
Sb2
363738606162727374108109
1*8121122168169170192193194228229
788082141
174175176242244246
1.00.03054xlO"4
1.00.0490.00141.00.0630.0021.00. 110.0043
0. 130.00621.00. 1730.01141.00.2040.0131.00. 181
1.00. 1370.00391.00.250
06121740391
0.561
1.0.3.1.0.0.1.0.0.1.0.0.1.0.0.1.0.0.1.0.0.
0033471xlO"4
00556001240066700186010010044501120055701560112601780148
1.00.9131.081.00.8811. 1381.00.9461. 1161.01.090.9631.01. 1491. 1061.01. 1081.0161.01. 1440.874
8.7.
11.13.
5.11.
9.3.
1510.
10.i.
14.12.
76
98
46
17
6
e6
442
1.00.211
1.00. 1440.005211.00.2166
1.00.6894.0661.01.4900.555
1.00.858 14.5
1.00.949 5.10.743 25.71.01.191 19. 1
1.01. 126 12.61.027 2.61.00.9331.010
6.71.0
a: Dev. is the percentage deviation of the experimental yield(z) from thepredicted yield(y).
124
3.1.4.2 ANALYSIS OF SLUDGE SAMPLES FROM STORAGE BAY OF THE
CiRUS REACTOR
K.L. Ramakumar, V.A. Raman, V.L. Sant, V.D.Kavimandan
and H.C.Jain.
Six sludge samples received from the storage pool of the CIRUS
reactor have been analysed for the trace constituents using
SSMS employing photoplate detection system. The powdered
samples were directly mixed with high purity graphite in 1:1
ratio by weight and homogenised. Table - 54 gives the typical
results obtained for one of the samples. It is seen that the
major constituents appear to be iron, Na, Mo, Ba and Pb with
iron being present at a level of about 6000 ppmw. P,Cr,Mn,Co,
Cu, Rb were also present but only at minor amounts.
Table - 54
Concentration of elements in sludge samples from CIRUS
Element Concentrationpg/g of U
Na 4696P 66Cr 82Mn 88Fe 6157Cu 62Rb 30Mo 216Ba 92Pb 213Pu 689
125
3.1.4.3 DETERMINATION OF ZIRCONIUM IN U-Zr-Al AND Pu-Zr-Al
SAMPLES BY THERMAL ION[SAT ION MASS SPECTROMETRY(TI MS)
K.L. Ramakumar, V.A. Raman, V.L. Sant, M.K. Saxena and
H.C. Jain.
Precise and accurate determination of Zr in alloy fuel
materials like U-2r-Al and Pu-Zr-Al is essential from the point
of view of its homogeneous distribution. Conventional methods
like spectrophotometry give results for Zr with accompanied
larger errors (5% or more). Other techniques like emission
spectroscopy and X-ray fluorescence also give results with
large uncertainties. An attempt has therefore been made to
standardise an isotope dilution method for the determination of
2r employing thermal ionisation mass spectrometry (TIMS).
Various parameters like sample dissolution, spike calibration,
proper chemical exchange between the sample and spike isotopes,
chemical separation of Zr and mass spectrometric analysis have
been investigated for achieving the optimum conditions-
Samples were dissolved in 6M HC1 + 0.1M HF. An enriched 9 1Zr
spike (atom percent ^ Z r = 95%) solution has been prepared by
dissolving enriched 9 1Zr02 in HC1 + HF. The spike was
calibrated against a standard solution of Zr obtained by
dissolving exactly known amount of ZrO2 in HC1+HF.
Concentration of the ^1 £r spike could be calculated with a
precision better than 0.2%.
A " Z r radioactive tracer has been employed to standardise the
conditions for the anion exchange separation of Zr from the
sample in HC1 medium. The sample solution was loaded on the
column in 10 M HC1. After washing down the Al with 10M HC1, Zr
was eluted in 2.5 ml of 3M HCI. The elution characteristics
126
were followed by counting the ^ 2 r activity on Nai(TI)
detec tor.
One of the critical parameters in the isotope dilution mass
spectrometry of Zr has been found to be the incomplete chemical
exchange between the zirconium in the sample and the spike.
Preliminary experiments carried out using Pu-Zr-Al sample
solutions resulted in large errors in the Zr concentration.
With a view to optimising the conditions for the complete
chemical exchange between the sample and spike, further
experiments were carried out with U-Al-2r samples.
It was found that proper chemical exchange could be ensured in
the presence of nascent hydrogen generated by the addition of
a small A) foil into the solution. Zirconium was then
separated employing conventional anion exchange separation
procedures in HC1 medium. The precision obtained in the mass
spectrometric analysis of 2r was about 1 percent.
Investigations are going on to improve the precision and also
to extend the method to Pu-2r-Al samples.
3.1.5 RADIOMETRIC ASSAY
3.1.5.1 DETERMINATION OF FLUORIDE BY RADIOMETRIC ASSAY
OF 1 8 1Hf BACK EXTRACTED FROM HTTA TN BENZENE.
M.A, Mahajan, R.K.Rastogi, N.K.Chaudhuri and S.K.Patil
In continuation with the study on back extraction of
from its thenoyl trifluoro acetone (HTTA) complex in benzene by
fluoride in aqueous solution, a method has been developed for
the determination of fluoride at low concentration level. A
0.01 M solution of HTTA in benzene was used for the extraction
127
of a suitable aliquot of 181Hf(IV) activity from aqueous
2M perchloric acid and a stock solution of *^Hf in benzene
solution of HTTA was prepared which could be used for several
experiments. 5 ml of this solution was equilibrated with 5 ml
of the aqueous solution containing varying concentrations of
fluoride. 2 ml of the aqueous phases were then gamma counted
for measurement of Hf(IV) back extracted.
Variation of time of equilibration showed that the equilibrium
was attained within 20 min. A shaking period of 30 mins. was
maintained in all subsequent experiments. Variation of the
acidity of the aqueous medium showed that 2 to 2.5 II in HCIO4
was most suitable. Hence acidity was maintained in this range
in subsequent experimets. When solutions containing varying
concentration of fluoride were equilibrated with equal volume
of the organic stock solution, the Hf(IV) back extracted showeda linear relation with the. concentration of fluoride in the
aqueous medium at least upto 10 microgram/ml. The range could
be extended by taking a higher initial concentration of Hf(IV)
in the organic phase. RSD in 11 replicate determinations at a
concentration level of 1.5 microgram/ml of fluoride was 2.2
percent.
One organic stock solution of l^Hf was used over a period of
one month without any adverse effect apart from the reduction
of activity level due to decay of *®*Hf. A study on the
effect of various foreign ions showed that 100 fold excess of
Cl-.NOjj, P O " ^ , 50 fold excess of SO" 2, and 100 fold excess of
biva l e n t cations like C a 2 + , H g 2 + , C d 2 + , N i 2 + etc. did not
interfere. Among the trivalent cations 50 fold excess of
C r 3 + , B i 3 + , and 10 fold excess of F e ^ + could be tolerated but
even 2 fold excess of A l 3 + interfered. Though 5 fold excess of
Z r 4 + could be tolerated, even 2 fold excess of T h 4 +
interfered. The distillate obtained by pyrohydrolysis of
128
nuclear fuel sample does not contain these interfering ions and
the sodium acetate buffer used for collecting the distillate
had no adverse effect. When a few unknown solutions were
determined using this method,the results agreed within 5
percent with those obtained by fluoride ion selective
electrode,
3.1.6 X-RAY FLUORESCENCE
3.1.6.1 X-RAY FLUORESCENCE ANALYSIS OF ZIRCONIUM
K.L. Chawla, N.D. Dahale and N.C. Jayadevan.
Plutonium-zirconium and uranium-zirconium alloys are important
metallic nuclear fuels. The chemical methods employed for the
analysis of zirconium include a gravimetric method using
selenius acid or mandelic acid and igniting to ZrO2-
Spectrophotometrica1 1y it is analysed us ;ng Arsenazo( I I I)
reagent for colour development. Fluoride ions which are used
to keep zirconium in solution interfere. These are either
expelled by evaporation or complexed with a 1 urniniurn( 1 I 1 ).
These procedures are time consuming. A rapid X-ray
fluorescence method for the analysis of zirconium in
solution was standardised. Yttrium was used as an internal
standard. Linear calibration plots between background
corrcted '2rK '''YK ratio and zirconium concentration were
obtained. Mo or W target X-ray tube was used. The precision
of the method was shout 1.3%.
Pure zirconium stock solution was made by dissolving zirconium
oxychloride in dilute HC1. Yttrium stock solution was made v.y
dissolving Y2O3 in HNO3 . Weighed amounts of these two
solutions were mixed in 5 ml volumetric flasks made up with
dilute HC1 to obtain a series of solutions for
129
c a l i b r a t i o n . 1 mi of t h e s o l u t i o n w a s t r a n s f e r r e d to a c e l l
a n d c o u n t e d a t e a c h of t h e t h r e e 2 0 ° a n g l e s c o n s i s t i n g of
b a c k g r o u n d ( 2 5 ° f o r M o t u b e s o u r c e a n d 2 2 ° f o r W t u b e
s o u r c e ) , 2 r K w l i n e ( 2 2 . 5 5 ° ) a n d Y K a line ( 2 3 . 8 0 ° ) . T h e
b a c k g r o u n d w a s c o r r e c t e d u s i n g t h e v a r i a b l e b a c k g r o u n d
m e t h o d c * -1.
T h e r e s u l t s o n t h e c a l i b r a t i o n f o r z i r c o n i u m s o l u t i o n s u s i n g M o
t a r g e t t u b e a r e g i v e n in T a b l e - 5 5 . T h e i n t e n s i t y r a t i o
Ip (= ' Z r ̂ ' Y ' c o u l d b e r e l a t e d to t h e c o n c e n t r a t o n r a t i o
Y / Z r , w h e r e Zr a n d Y a r e t h e z i r c o n i u m a n d y t t r i u m
c o n c e n t r a t i o n s r e s p e c t i v e l y , t h r o u g h t h e l i n e a r r e l a t i o n :
I pj = m ( Z r / Y ) . T h e s l o p e m r e m a i n s a l m o s t c o n s t a n t for t h e
e n t i r e c o n c e n t r a t i o n r a n g e of 0.3 to l m g / m l of z i r c o n i u m a n d
h a s a p r e c i s i o n of 1.3%. L i n e a r c a l i b r a t i o n p i o t s p a s s i n g
t h r o u g h t h e o r i g i n in t h e c o n c e n t r a t i o n r a n g e of G . 3 to
lmg.'ml of z i r c o n i u m u s i n g M o or W t a r g e t t u b e s a r e
shov. in F i g . 1 0 . U s e of U t u b e i n c r e a s e s t h e s l o p e m f r o m
0 . 3 5 f o r ,'1o t u b e to 0 . 8 0 as e x p e c t e d w i t h i n c r e a s e in t h e
a t o m i c nu.nber of t h e t a r g e t m a t e r i a l . F u r t h e r , c h a r a c ter i •.. ' ; r
l i n e of M o t a r g e t l i e s on t h e long w a v e l e n g t h s i d e of the I''
a b s o r p t i o n e d g e of z i r c o n i u m .
W h e n s o l u t i o n s of P u - Z r - A l a l l o y s c o n t a i n i n g a b o u t 2% r i r c o n i u m
s o l u t i o n s w e r e a n a l y s e d no p e a k for z i r c o n i u m w a s o b s e r v e d .
P l u t o n i u m is f o u n d to a b s o r b 2 r K & i n t e n s i t y b e c i u s e
c o m p a r a t i v e l y s m a l l e r a m o u n t of z i r c o n i u m is p r e s e n t
a s s o c i a t e d w i t h l a r g e r a m o u n t s of p I u t o n i um m a t r i x h a v i n g
h i g h e r m a s s a b s o r p t i o n c o - e f f i c i e n t for riu as w e l l a s U
r a d i a t i o n . T h e m e t h o d d e s c r i b e d h e r p c a n be u s e d f o r s u c h
s o l u t i o n s o n l y a f t e r c h e m i c a l s e p a r a t i o n of p l u t o n i u m , s i n c e
in t h e s e e x p e r i m e n t s , 1 ml s o l u t i o n s w e r e u s e d to a v o i d
h a n d l i n g of l a r g e a m o u n t s of p l u t o n i u m . W e p l a n to u s e b i g g e r
4.0
uOu
CO
COI
3.0
A Mo TUBE
° W TUBE
2.0 3.0Zr CONCENTRATION, mg
Fig 10.CALIBRATQN PLOTS FOR ZIRCONIUM.
4.0 5.0
130
cells containing larger amounts of solution to obtain
calibration plots with different amounts of plutoniura, so as to
analyse zirconium without chemical separation of plutonium.
Reference.
1. D. Ertel, J. Radioanal. Chem., 2,205(1969).
Table - 55
Relationship between Intensity RatioConcentration ratio Y/2r
and
AmountZr
mg
1.4456
1.5275
1.8704
3.0129
4.4782
2
2
2
3
3
ofY
.8584
.5202
.4580
.6298
.0174
1 a tens i tyratio after
Bkg. correction
0.1759
0.2136
0.2750
0.2932
0.5303
'R
Mean
( l Rx(Y/Zr)
0.3478
0.3524
0.3614
0.3532
0.3573
0.3544• 1.3%
131
3.2 PRIMARY CHEMICAL ASSAY STANDARDS
3.2.1 PRIMARY CHEMICAL, ASSAY STANDARD FOR URANIUM
K.D. Singh Mudher, R.R. Khandekar, K. Krishnan, N.C.
J a y a d e v a n a n d D . D . S o o d
T h e a s s a y o f u r a n i u m i n n u c l e a r f u e l is vf.uy i m p o r t a n t f o r
q u a l i t y a s s u r a n c e f o r e n s u r i n g s t r i c t c h e m i e / ' l s p e c i f i c a t i o n s
r e q u i r e d f o r o p t i m u m p e r f o r m a n c e . O u t o f t h e f e w e v a l u a t e d
c h e m i c a l a s s a y s t a n d a r d s f o r u r a n i u m , U^flg is the? n n e c o m m o n l y
u s e d a n d i s a v a i l a b l e a s N I S T r e f e r e n c e m a t e r i a l . H o w e v e r , i t s
s t o i c h i o m s t r y d e p e n d s o n t h e s t a r t i n g c o m p o u n d . s a m p l e ? s i z e ,
t e m p e r a t u r e a n d d u r a t i o n o f i g n i t i o n . R u b i d i u m u r a n i u m
s u l p h a t e i . e . R b 2 U ( S 0 4 ) 3 h a s h e n e v a l u a t e d a s a p r i m a r y
c h e m i c a l a s s a y s t a n d a r d f u r u r a n i u m .
U r a n i u m d i o x i d e o b t a i n e d f r o m U r a n i u m N e t a i F I n n 1. , B A R C a a ?
d i s s o l v e d i n n i t r i c a c i d , p r e c i p i t a t e d a s a i E w o n i uni •! i u r a n g t n ,
f i l t e r e d , d r i e d a n d c o n v e r t e d t o U O 3 a t 3!H.i - -,00 ° C . It w a s
d i s s o l v e d i n 1 M H 2 . S O 4 a n d U ( V I ) r e d u c e d t o U < I V > i n ,->••,
e l e c t r o l y t i c c e l l u s i n f * p l a t i n u m P I P C U o d " ? a s r.hcwn i n
F i g . 1 1 . R b 2 C 0 3 (Rs 1 . 2 t i m e s ) w a s a d d e d t o I J ( 1 V ) s o l u t i o n w h i c h
wa::. e v a p o r a t e d u n d e r 1R l a m p t o g i v » g r e e n c o l o u r e d c r y s t a l s
f R b 2 U ( S 0 4 ) 3 w h i c h w e r e w a s h e d w i t h a b s o l u t e a l c o h o l
s e v e r a l t i m e s . S e v e n d i f f e r e n t l o t s o f 3-!5r; of R b v ' M S O / , ) ^
w e r e p r e p a r e d . T h e s a m p l e s p r e p a r e d v •--•;,• • •!; - r a." • c r i ?; e d l.iy
d i f f e r e n t c h e m i c a l a n d p h y s i c a l nu.'t Inul:;,
D o t h u r a n i u m a n d s u l p h a t e w e i •' 1 • h •-» ..1 i <.';, 1 i / <• n.. 1 y ;. ( • * . U r a n i u m w a s
a n a l y s e d b y t h e D a v i e s a n d G r a y m e t h o d . S u l p h a t e w a s
a n a l y s e d g r a v i m o t r i c a I 1 y sr, HciSD,, a i I < • 1 :; i.'pa 1 ;> t i 111; u r a n i u m b y
p r e c i p i t a t i n g it w i t h a m m o n i a . T h e r e s u l t s o f c h e m i c a l a n a l y s i s
o f s e v e n d i f f e r e n t l o t s a r e g i ven i n T a b 1 ? - 5 C . It i s s e e n
ANODE CATHODE(-)
1M H2SO4
Pt WIRE
Pt WIREMESH
URANYLSULPHATESOLUTION
FRlTJ
FIG.-11 ELECTROLYTIC CELL USED FOR REDUCTION OF URANIUM(YI)TO URANIUM(E?).
from the results that the deviations of the experimental values
from the expected values for both uranium and sulphate are
within the precision of the methods employed.
The purity of the material was determined by taking into
account the concentrations of trace metal lies obtained by AES
method. Thus total impurity content was found to be less than
0.03%, thereby giving the guarantee that the material can be
prepared in pure form.
The 1R spectrum of Rb2U(S04>3 (Fig. 12) shows that there is no
water of hyjration in the compound since the bands
due to 0-H stretch around 3500cm" 1 and H-O-H band around 1600
em'^-are absent. The appearance of (nue-3) V3 absorption
frequencies (S-0 stretching modes) at 1000- 1250cm~ *• which are
higher than those present in U(SO4)2-4H2O suggests that
3 contains chelating sulphate groups.
The cell parameters of Rb2U! 30.4)3 a s derived from single
crystal X-ray Weissenberg photographs and refined by least
squares methods are given in Table -b7. The compound belongs
to the monoclinic system.
Thermal analysis as shown in Fig.13 confirms the absence of
water of hydration. On heating in air there is no weight loss
upto 550°C, beyond which it decomposes at 6 50°C to form
Rb2U02(SO4 ) 2• On further heating, the compound decomposes above
800°C with 3 continuous loss to form K'"12'-)2(-'7 •
It is clear therefore that RI.^LMSO/.,^ is a stable, anhydrous
compound which can be easily prepared in a pure form. It is
also found to be easily soluble in common acids. Thus the
material meets most of the requirements of a primary chemical
assay standard.
UJo•z.<
COz:<Q:1- 4000 3000 2000 1600 1200
WAVE NUMBER (cm"1)
800 400
FIG.-12. IR SPECTRUM OF Rfc>2 U { S04> 3 .
WT. OF SAMPLE = 517.5mg \
TEMPERATURE ( C)
Fig 13. TG AND DTA CURVES OF Rb2U(S04)3.
133
LotNo.
1.2.3.4.5.6.7.
MeanR.S.D
34343434343434
340
Assay
. 14
.10
.07
. 13
.20
.07
. 13
.12
.13
of uranium
Deviationexpected
- 0,- 0.- 0.- 0.+ 0.- 0.- 0.
- 0.
.03, 15,23,06,152306
09
Table -
and sul
fromvat ue
56
phate ir
SO4"
*
41.41.41.41.
41.0.
1 Rb;
11262227
2218
2U(SO4J3
Deviation from+
expected value
- 0.- 0.- 0.- 0.
- 0.
,51,15,24,12
24
* expected value 34.15% + expected value 41.32%
a
b
c
6
Cell
0(A)
0(A)0(A)»( )
z
Table
Parameters
- 57
of Rb2U(S04
9.
16.
22.
114
454
487
959
1,8
12
>3
(5)
(8)
(9)
(1)
Density-* measured, g.cm_^ 4.17Density-* calculated, g. cm *" 4.27
134
3.2.2. PRIMARY CHEMICAL ASSAY STANDARD FOR PLUTONIUM
K.D. Singh Mudher, R.R. Khandekar, K.Krishnan,
N.C. Jayadevan and D.D. Sood
Out of several materials proposed and evaluated as primary
chemical assay standards for plutonium, Pu(SO4)2-4H2O has been
found to meet most of the requirements of primary standard and
has been prepared as an NIST standard. However, being a nuclear
material, it is not easily available. Double sulphates of
plutonium with alkali metals are known for quite some time.
Some of them are stoichiometric and can be easily prepared.
Anhydrous potassium plutonium sulphate K4Pu(S04>4 has been
evaluted as primary chemical assay standard for plutonium.
Plutonium was purified by loading on an anion exchange column
in 7M HNO3 . The plutonium in nitric acid was evaporated to
dryness and crystallised as Pu(SO4)2-AH2O by adding 4M H2SO4.
Crystals of Pu(SO4)2-4H2O were washed with alcohol and
dissolved in 1M H2SO4 and slight excess of K2SO4 solution than
required for stoichiometry was added. Green coloured crystals
of K4PU(SO4)4.2H2O were obtained on heating under an IR lamp.
The crystals were washed with absolute alcohol and dried in
air. These crystals were heated to 300°C for 3-4 hours to
obtain red coloured anhydrous !<4Pu(S04)4. Samples were prepared
in five lots at 2-5g level and stored in glass-stoppered
bottles. The anhydrous potassium plutonium sulphate was
characterised by chemical analysis, X-ray diffraction, infra-
red and thermogravimetric methods.
Analysis of plutonium was carried out by titrimetric methods
whereas sulphate was analysed gravimetrica11y as BaS04 . The
results of chemical analysis of five lots of anhydrous
l<4Pu(S04)4 prepared separately are given in Table -58. The
135
2-standard deviation calculated for Pu and SO4 analyses are
within the precision of the analytical methods. The total
impurity content as determined by spark source mass
spectrometric and emission spectrographic analysis was below
300 ppm. Anhydrous salt stored over a period of six months in
a desiccator has shown no weight change indicating that the
samples are stable to alpha radiolytic effects and atmospheric
cond i t i ons.
The inf rB.fed spectra of samples showed that the number of
absorption bands observed were more than that required for
even the lowest symmetry of the molecules, suggesting the
presence of two or more molecular groups in the unit cell.
Thermogravimetric patterns indicated that the compound is
•stable upto 700°C, beyond which it decomposes to give K2SO4
and
Thus anhydrous K4Pu(S04>4 has been found to meet most of the
requirements of a primary chemical assay standard for
plutonium. It has a defined stoichiometry and is easy to
prepare. It is easy to purify and dissolves easily in acid
solution. It is stable to atmospheric and alpha radiolytic
effects. It is stable as anhydrous salt upto 700°C. The
results of preparation at 2-5 gm level of Pu in five different
lots have shown quite satisfactory results. Studies are
planned with larger amounts of plutonium.
136
Table - 58
2-Assay of Pu and SO4 in K^Pu!504)4
Lots
12345
MeanR.S.D.
3030303030
300
Pu
.64
.68
.71
.71
.74
.69
.14
Deviation from ^expected value
+ 0. 12- 0.01+ 0.09+ 0.11+ 0.20
+ 0.10
SO4"
49. 1649.5049. 1349. 1349. 18
49.220.32
Deviation frora+expected value
- 0.26+ 0.42- 0.32- 0.32- 0.08
- 0.10
* expected value 30.66X + expected value 49.27%
3.2.3. CHARACTERISATION OF INDIGENOUSLY PREPARED CHEMICAL ASSAY
STANDARD FOR PLUTONIUM
K.L. Ramakumar, V.A. Raman, V.L. Sant, V.D. Kavimandan
and H.C. Jain
Double sulphate of potassium and piutoniurn,K4PU(SO4)4. has
been identified to be the prospective candidates for the
possible use as chemical assay standard. A test lot of
K4Pu(S04)4 prepared in the Division has been characterised for
the trace constituents by spark source mass spectrometry (SSMS)
employing photoplate detection system. With a view to
minimising the isobaric interferences at mass numbers of
interest, the photoplate exposure was carried out at higher
resolution (""40001. As both potassium and sulphur form
different molecular ions between themselves and also with
carbon and oxygen present in the sample, the identification of
the mass numbers for the impurity element was carefully arrived
at by checking the isotopic distribution as welI as the
137
p r e s e n c e o r a b s e n c e of any n o n - i n t e r f e r i n g m o l e c u l a r i o n n e a r
t h e s e mass n u m b e r s . At t i m e s more t h a n one i s o t o p e of t h e
e l e m e n t was m o n i t o r e d t o c r o s s c h e c k t h e r e s u l t s o b t a i n e d .
T a b l e - 59 g i v e s t h e c o n c e n t r a t i o n of t h e t r a c e c o n s t i t u e n t s
d e t e r m i n e d in K4Pu
This work is being carried out as part of the Divisional
efforts to prepare and characterise a chemical assay standard
for piutoni um.
Table - 59.
Concentration of trace constituents in K4Pu(S04>4
S.No. Element Concentration ppmw with
1. Sodium2. Aluminium3. Phosphorus4. Titanium5. Manganese6. Cobalt7. Nickel8. Copper9. Zinc
10. Molybdenum11. Tin12. Antimony13. Barium14. Tungsten15. Lead16. Bismuth17. Arsenic18. Silver19. Cesium20. Platinum21. Thorium22. Uranium
Note: For elements 1 to 18, the concent ra t ion has beenca l cu l a t ed by assuming the c a l i b r a t i o n fac to r s (RSF) determinedin U3O0 matrix. For elements 19 to 22, a uni t c a l i b r a t i o nfac tor iRSF) has been assumed.
Concentrat iorrespect to K̂
5 3 .1 4 .
1.8.1.1.9.4 .
16.10.2 .0 .7.1.2.1.0.3 .6.
39 .10.4 6 .
i ppmwjPulSO/,
7608506102391557682351
138
3 . 2 . 4 . S T U D I E S O N T H E S T O I C H I O M E T R Y A N D S T A B I L I T Y O F R U B I D I U M
URANIUM TRISULPHATE
A.U. Bhanu, L.R. Sawant.P.K. Kalsi and S. Vaidyanathan
Double sulphates of uranium and plutonium were prepared
as possible substitutes to primary chemical assay standards.
One of the compound under study is rubidium uranium sulphate
Rb2U(S04>3. To confirm its stoichiometry , it is proposed to
estimate uranium, rubidium and sulphate content individually.
The work was initiated to standardize the suitable methods for
sulphate and rubidium.
Sulphate estimation.
The major task was to remove uranium and then do an accurate
determination of sulphate. Gravimetry procedure of
precipitating sulphate as BaSO/^ was used. The results
obtained were ± 0.3% accurate. The parallel runs of sulphate
determination in sulphuric acid (standardised against Na2C03)
and K2SO4 were carried out. Both are showing the similar trend
in accuracy indicating the limitation of the accuracy level
that could be attained.
Rubidium estimation.
T o s t a n d a r d i s e t h e g r a v i m e t r i c m e t h o d f o r r u b i d i u m e s t i m a t i o n
p u r e R b C 1 w a s a n a l y s e d b y p e r c h l o r a t e p r e c i p i t a t i o n m e t h o d s .
T h e r e s u l t s o b t a i n e d w e r e o n t h e l o w e r s i d e a n d u p t o 9 9 . 4 % of
the values expected.
Stability of Rb 2U(S0 4) 3.
A study has been initiated to observe the stability of rubidium
uranium sulphate both in presence and absence of light, by
determinating the uranium content periodically. For this
purpose, two samples of Rb2U(S04)3 were taken. One cample was
139
kept in a dark container and the other sample in a transparent
glass weighing bottle. The uranium content is being determined
periodically by potentiometry. The uranium contents at the time
of storage were 34.24% and 34.22% respectively in the presence
and absence of light. The corresponding values after two
months were 34.14% and 34.14% respective1y.This work is being
con t i nued.
3.3 ANALYTICAL SERVICES
3.3.1 ANALYSIS OF NUCLEAR FUEL SAMPLES FROM RADIO-METALLURGY
DIVISION
760 samples of different types, like oxides, nitrides,
carbides etc. were received from Radio-metallurgy Division
for determination of various specifications, such as U,Pu, 0/M
ratio, isotopic composition etc. Table - 60 gives a summary of
the number and types of samples analysed for different
spec i f i cat ions.
3.3.2 ANALYSIS OF SAMPLES FROM OTHER DIVISIONS AND RESEARCH
GROUPS.
Analytical services have been rendered to various units of
D.A.E. and other Divisions of BARC towards their on-going
research and development activities. Table - 61 gives more
details on these analyses. Analytical services also included
distribution of samples received from various sources to
different Sections of FCD for carrying out the determinations
of the required specifications.
140
Table - 60
Analyses of Samples received from R(1D.
Pu 0/M 2 3 3U XRD 0 NSample UDescription
C Cl,F H20 Isot-opic
Total
Pu + HC1solutionUN(l/Pu)02(UPu)NU02Th02-Ti02
Zr-NiAl-Pu alloyAI-233U-ZrTh02-U02
Al-Pu-Zr alIThO2
Ti-Al alloyU3O8U02 +PuO2 +CUC
25
212108-----oy-- •
6: 24
NaOH solutionThO2 -Nb205
U02 + ZrO2
U02 +CaOU02 +MgOU02 + Nb205
U02 +Ti02
U02 +U205U02 +Y203
Etched NaOH
-1------1
31
-210---
20--
67--6263--------2
-
---
291---4-1-3---4-111111-
1
183
10_
190
104
—
-
6
-
6
33
8 B
57
3944
4065142033h
671
16154183411111113
Total 80 149 48 33 4 205 216 6 760
141
Table - 61
S. SampleNo. description
Number ofsamples
Units Analysed for
1.2.3.
4,
5.6.7.
8.9.10.
11.12.
13.14.
15.
16.
. Uraniumi Uranium, Uranium
, Uranium,piutoniumand dissolversolution samples.Boric anhydride
5111017
19
2Lithium pentaborate 2Plutonium and
(U.P'i)CSS samplesCs2Cr2C>7Molybdenum samples
Sludge samplesRare earth salts
YAG:NG CrystalWater
Steel and Iron
Titanium and2 irconium
3
318
63632516
42227
29
544
Ch.T.D.MDRSChemicalGroupFRD
A.Ch.D.NAPPRMD
RMDFCDUniv. ofMadrasC1RUSRCDRCDRCDChemicalGroupChDUCDTPPEDDEEDDFEDPhys icalMetallurgyMetal 1urgyMetal Iurgy
235y/238y a t o m r ati 0 s by TIMS.2 3 5U/ 2 3 8U atom ratios by TIMS.2 3 5U/ Z 3 8U atom ratios by TIMS.
Isotopic Composition andconcentration of uranium andPlutonium by TIMS.1 0B/ nB atom ratio by TIMS1 0B/ HB atom ratio by TIMSIsotopic Composition andconcentration of uranuim by TIMSB by SSMSTrace impurities by SSMSTrace impurities by SSMS
Trace impuritiesN i trogenX-Ra> DiffractionThermalX-Ray Diffraction
X-Ray DiffractionX-Ray DiffractionX-Ray Diffraction
FNC
HX-Ray Diffraction
Grand Total 766
142
4. NUCLEAR MATERIALS ACCOUNTING
4.1 NUMAC DATABASE
N. Maiti, P.N. Raju and S. Vaidyanathan.
During 1988, the NUMAC database has been augmented to include
the data on HEU from APSARA. Data from APSARA has been loaded
in the database from May 1987 to uptodate.
During this period, 563 accounting reports were received from
12 facilities. These were checked for internal consistency and
loaded in the NUMAC database. On the last day of each month an
inventory status report was prepared depicting the number of
accounting reports received, consolidated status of inventory
of nuclear materials, their location and form as well as
nuclear materials in transit, if any.
The increased use of PCs by almost all the fuel cycle
Facilities in the DAE is opening new avenues for the nuclear
materials accounting. It was felt useful to receive the data
from the Facilities through floppy discs instead of the
reporting forms. Receiving data through floppy discs has the
following advantages namely, (i) the confidentiality of the
data can be maintained ; (ii) time saving; and (iii) no chance
of transcription errors, etc.
This can also be extended to the safeguards data which are
being communicated to IAEA .
143
To equip ourselves for the implementation of this , a micro
computer system (QUANTUM AT) of 1 MB main memory with 20 MB
hard disk, 5 1/4" floppy disk drive and advanced link software
to communicate between the HP computer system and any other
computer system has been selected. To get the system,
necessary follow up work has been taken up.
4.2. TIME SERIES ANALYSIS
M.B. Yadav and Hari Singh.
A time series study of UCIL monthly production data for
uranium (1975-1988) has been carried out. Monthly production
data for uranium from March 1985 to December 1988 have been
used for this study. Multiplicative model of Time Series
Y = TCS1 has been used. Different components of time series
viz., Trend, Cyclic, Seasonal and regular have been
estimated. These estimates have been used in forecasting
the monthly uranium production upto the year 1995. Irregular
component has been used in estimating the error in
forecasting. The 95 percent confidence intervals for the
predicted values have been estimated. As part of this
jtudy, four computer programmes namely, TIMES, SEASON, CYCLE
and PRD were developed on HP-1000 system.
144
4.3. SOFTWARE DEVELOPMENTS
5. Jyothi and Hari Singh.
A Iibrary program GAUSS for determining the integral of a real
valued function on a given interval was developed based on a
recursive alogorithm employing the 20-point and 10-point GAUSS
quadrature formulas.
A number of computer programmes such as QUADM, PEARS, W-TEST,
KSTAT and PROBEQ developed earlier on the BESM-6 and ND-500
computer systems of BARC, have been modified so that they could
be run on the HP-computer system of NUMAC. These programmes
are useful in carrying out MUF analysis studies.
4.4. INSTRUMENTATION
D.B.Paranjape and S. Vikram Kumar
The procurement of various components of a 4096 channel
analyser is underway for assembling it in collaboration with
Health Physics Division. This MCA is 8085 based NIM compatible
system coupled through 100 MHz ADC. A gamma ray spectrum can be
acquired and analysed after proper shaping and amplification of
the detected signal. The ADC and the display units have yet to
be received. All the necessary units to set up a silicon
surface barrier based oc-spectrometry have been tested.
The pipe line that connects both the detector's vacuum chamber
and the thermocouple gauge to the vacuum pump is under
fabr ication.
145
A dehumidifier has been procured and this would
in the counting room for humidity-control.
be instal1ed
The electronic circuitry of a photovoltaic pressure
switch/gauge that will be connected to the glove boxes to
control/monitor the inside pressure has been modified according
to the user needs. Both the lower and upper set points
provide good control on the pressure. It has been modified to
latch the relay once the pressure inside the glove box is out
of the set pressure range.
146
5. LIST OF PUBLICATIONS DURING 1908
1. Thermodynamic properties of Cr(1_x)Tex for x - 0.546 and 0.526,R. Prasad, V.S. Iyer, Z. Singh, V. Venugopal, S. Mohapatra and D.D.Sood , J.Chem. Thermodynamics, 20.,319(1988).
2. Thermodynamics of FeTeg.g,R. Prasad, 5. Mohapatra, V.S. Iyer, V. Venugopal and D.D. Sood, J.Chem.Thermodynamics, 20.45311988).
3. Standard Gibbs molar free energy of formation of Na2ZrO3,V.S. Iyer, V. Venugopal, R. Prasad, Z. Singh, S. Mohapatra and D.D.Sood , J.Chem. Thermodynamics, 20.751(1985).
4. Vaporisation thermodynamics of CS2M0O4 ,R.P. Tangri, V. Venugopal, D.K. Bose and M. Sundaresan, Paper presentedat the International Symposium on Thermodynamics of NuclearMaterials held at Chicago, USA, September!1988).
5. Thermal properties of Cs2Cr207<s,I) by high temperature calorimetry,R. Prasad, Renu Agarwal, K.N. Roy, V.S. Iyer, V. Venugopal and D.D.Sood, Paper presented at the International Symposium onThermodynamics of Nuclear Materials held at Chicago, USA,September(19881.
6. Effect of lanthanum, neodymium, thorium, uraniun and plutoniumcompounds on graphite oxidation,S. Sampath, N.K.kulkarni, M.S. Subramanian and N.C. Jayadevan, Carbon,2J., 129(1988).
7. M2U4O12 compounds of potassium, rubidium and thallium,K.L. Chawla. N.L. Misra and N.C. Jayadevan. J. Nucl. Materials,154.181(1988).
8. Structural and thermal investigations on tetrasulphate complexes ofuranium)IV) and plutoniumtIV),K.D. Singh Mudher, K. Krishnan, D.M. Chakraburthy and N.C. JayadevanJ. Less Common Metals, 143.173(1988).
9. A Potentiometric method for the determination of uranium by stannouschloride reduction,Mary Xavier and N. Jayanthi, J. Radioanal. Nucl. Chen. Articles,122.65(1988).
10. Experimental evaluation of the characteristic features ofpassivated ion implanted and surface barrier detectors for alphaspectrometry on plutonium,S.K. Aggarwal, R.K. Duggal, P.M. Shah, R. Rao, and H.C. Jain, J.Radioanal. Nucl. Chem. Articles, 12011).22119B8I.
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11. Simultaneous determination of the 235y/23By isotope ratio andconcentration at nanogram levels of uranium employing a mixed spikein thermal ionisation mass spectrometry,S.K. Aggarwal, R.K. Duggal, P.M. Shah and H.C. Jain, Int. J. MassSpectrom. Ion processes, 85,13711968).
12. Determination of trace constituents in tellurium and zircaloy-2employing spark source mass spectrometry,K.L. Ramakumar, V.A. Raman, V.L. Sant, V.D. Kavimandan and H.C. Jain,J. Radioanal. Nucl. Chera. Letters,125(2). 467(1988).
13. Determinaton of uranium and plutonium in plutonium based fuels bysequential amperometric titration,P.R. Nair, K.V. Lohitakshan, Mary Xavier, S.G. Marathe and H.C. Jain,J. Radioanal. Nucl. Chem. Articles.12211).19t1988).
14. Complexometric determination of thorium in 2S.F. Hasilkar, N. Gopinath, Keshav Chander, S.G. Marathe and H.C. JainJ. Radioanal. Nucl. Chem. Letters.122(1).69(1988).
15. Spark source mass spectrometry in nuclear technology for traceanalysis,H.C. Jain and K.L. Ramakumar,Paper presented at the 11th International Mass SpectrometryConference, France, August-September(19881.
16. Iterative computational method for rapid analysis of Fe and Pu byCPC and some interesting observations on the coulogram of Pu(III),R.C. Sharma, P.K. Kalsi, L.R. Sawant, S. Vaidyanathan and R.H. Iyer,J. Radioanal. Nucl. Chem. Letters. 126, H1988).
17. Assay of uranium in scrap and waste produced at natural uranium metalproduction and fuel fabrication plants,A.U. Bhanu, P.C. Kalsi, S. Sahoo and R.H. Iyer,J. Radioanal. Nucl. Chem.Articles, 121.29-4511988).
18. Some obervations on the superconductivity in Tl-Ca-Ba-Cu-0 System.Ram Prasad, N.C, Soni, R.V. Kamat, V.N. Vaidya, C.V. Tomy and S.K.MalikPaper presented at the Solid State Physics Symposium held at BhopalDec 20-23,1988
19. Mass Spectrometry in Nuclear Technology : Two decades of ourexperience,H.C. Jain,Invited talk IT-4, Fourth National Symposium on Mass spectrometry,lISc, Bangalore, January 4-6(19881
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20. Diffused peaks in spark source mass spectrometry,K.L. Ramakumar, V.D. Kavimandan, C.S. Subbanna, V.A. Raman, V.L. Santand H.C. Jain, Paper No. 1-12, Ibid.
21. Comparison of relative sensitiviy factors in pure U3O8 and U3O3-Cmatrices,K.L. Ramakumar, V.A. Raman, V.L. Sant, V.D. Kaviraandan and H.C. Jain,Paper No. NT-6, Ibid.
22. Analysis of plutonium bearing fuel materials by spark source massspectrometry employing electrical detection system,K.L. Ramakumar, C.S. Subbanna, V.D. Kavimandan, V.A. Raman, V.L. Santand H.C. Jain, Paper No.1-13, Ibid.
23. Relative sensitivity coefficient in spark source mass spectrometry andits relation with element sensitive physico-chemical properties,B.P. Datta, V.L. Sant, V.A. Raman, V.D. Kavimandan and H.C. Jain,Paper No. NT-7, Ibid.
24. Determintion of isotopic composition of nanogram amounts ofuranium using U-233 as a spike,S.A. Chitambar, A.R. Parab, P.S. Khodade and H.C. Jain,Paper No.NT-8, Ibid.
25. Isotope fractionation factors in thermal ionisation massspectroraetric analysis of uranium and plutonium,S.A. Chitambar, P.S. Khodade, A.R. Parab and H.C. Jain,Paper No.NT-9, Ibid.
26. Sol gel process for fuel fabrcation,V.N. VaidyaInvited talk at Radiochemistry and Radiation chemistry Symposium,BARC;Bombay, Feb. 1988
27. Macroporous resins in actinide separations,V.V. Ramakrishna, Invited talk, Ibid.
..3. Dissoluton of UC for Coulometric determination of .1),N. Gopinath, J.V. Kamat, H.S. Sharma, S.G. Harathe and H.C. JainPaper No. CT-01, Ibid.
29. Recovery of Pu from phosphoric acid waste using mono octylphenyl phosphoric acid,V. Shivarudrappa, P.D. Mithapura, S.G. Marathe and H.C. JainPaper No. CT-07, Ibid.
30. Studies on the recovery of Pu from solutions containing thoriumand EDTAR.B. Manolkar, Keshav Chander, S.G. Marathe and H.C. Jain,Paper No. CT-08, Ibid.
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31. Studies on the sorption of plutonium on alumina from carbonate Media,A. Kadam, C.V. Karekar, M.M. Charyulu, C.K. SivaranakrishnanPaper No. CT-13, Ibid.
32. Measurment of stability constants of the F" complexes of tetravalentactinides using F~ ion selective electrode -A feasibility study ofTh(IV),R.M.Sawant and N.K. Chaudhuri, Paper No.CT-14, Ibid.
33. The extraction of U(V!) froraHCl acid by D2EHPA and nixtures ofD2EHPA and HTTA.R.D.Bhanushali, S.Negi and V.V.Ramakrishna, Paper No.CT-17, Ibid.
34. Extraction of Put IV) by D2EHPA from sulphuric acid medium,D.G.Phal,S.Kannan,V.V.Ramakrishna, Paper No. CTrf-18, [bid.
35. Influence of nitrate ion on the extraction of PuUVJby D2EHPA fro*sulphuric acid medium.S. Kannan, D.G. Phal and V.V. Ramakrishna, Paper No. CT-19, Ibid.
36. The extraction behaviour of Pu (IV) from nitric acid and- nitric-perchloric acid mixtures into D2EHPA,
D.G.Phal , S. Kannan, V.V. Ramakrishna, Paper No. CT-20, Ibid.
37. Synergic extraction of Pu((V) from nitric acid medium by D2EHPA withHTTA and TOPO,5. Kannan, D.G.Phal, V.V. Ramakrishna, Paper No. CT-21, Ibid.
38. The solvent extraction behaviour of Pu(VI) from perchloric acid byD2EHPA,K.V. Chetty, P.M. Mapara, Rajendra Swarup, V.V. Ramakrishna,Paper No. CT-22, Ibid.
39. Some studies on the extraction of Pu from phosphate containing HNO3solution using DBDECMP as extractant,V.B. Sagar, S.M. Pawar, M.S. Oak, C.K. SivaramakrishnanPaper No. CT-24, Ibid.
40. X-ray studies in Rb-U-Ca-0 system characterisation of a new nixedoxide phase,K.D. Singh Kudher, R.R. Khandekar, A.K. Chadha, N.C. Jayadevan,Paper No. CT-26, Ibid.
41. Reactions of rubidium and caesium with U02-Th02 oxides,K.L. Chawla, N.L. Mishra, N.C. Jayadevan, Paper No. CT-27, Ibid.
42. Engineering scale facility for the production of UO3 gel spheres,R.V. Kamat, J.V. Dehadraya, N. Kumar, T.V. Vittal Rao, V.N. Vaidya,D.D. Sood, Paper No. CT-28, Ibid.
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43. Synthesis of uranium raonocarbicte microspheres by sol-gel process,S.K. Mukerjee, J.V. Dehadraya, Y.R. Bamankar, V.N. Vaidya, D-D. Sood,Paper No. CT-29, Ibid.
44. Kinetics of nitrate leaching from UO3 gel particles prepared byinternal gelation process ,S.K. Mukerjee, V.N. Vaidya, D.D. Sood, Paper No. CT-30, Ibid.
45. Spectro-photometric studies on the behaviour of plutonium in basicmedia,M. Ray, l.C. Pius, M.M. Charyulu, C.K. Sivararaakrishnan,Paper No. CT-36, Ibid.
46. Studies for the electrodeposition of milligram amounts of uranium onelectropolished stainless steel disksS.K. Aggarwal, P.M. Shah, R.K. Duggal, H.C. Jain, Paper No. CT-39, Ibid.
a-47. Studies on the decontamination factors using oiicroporous anion exchange
resins,U.M. Kasar, l.C. Pius, V.B. Sagar, A.R. Joshi, C.K. Sivaramakrishnan,Paper No. CT-44, Ibid.
48. Absolute yields of fission products of ^^Mo and ^2je j n
spontaneous fission of "^Cf,V.K. Bhargava, M.S. Oak, A. Ramaswami, Satya Prakash,Paper No. NR-07, Ibid.
49. Determination of half life of 2 4 0Pu relative to half life of 2 3 3U,S.A. Chitambar, P.S. Khodade, A.R. Parab, H.C. Jain,Paper No. NR-09,Ibid.
50. Direct potentiometric determination of uranium in organic extractsusing Tit III) as reductant,A.K. Pandey, P.C. Kalsi, R.C. Sharma, S. Vaidyanathan, R.H. Iyer,Paper No. RA-01, Ibid.
51. Determination of U by Till II) reduction and biamperometric redoxtitration,P.R. Nair, K.V. Lohithakshan, Mary Xavier, S.G. Marathe, H.C. Jain,Paper No. RA-02, Ibid.
52. An improved method for the rapid determination of uranium bycontrolled potential coulometry using lingane's equation,R.C Sharma, P.K. Kalsi, L.R. Sawant, R.H. Iyer, Paper No. RA-03, Ibid.
53. Titrimetric determination of uranium in U-Pu- alloy,S.P. Hasilkar, Keshav Chander, S.G. Marathe, H.C. Jain,Paper No. kA-04, Ibid.
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54. Assay of uraniumAMgF2 slag generated in the magnesiothermic reductionof UF4 at the natural uranium concentrates,P.C. Kalsi, A.K.Pandey, R.H. Iyer, Paper iio. RA-07, Ibid.
55. Controlled potential coulometric deternination of Pu at aicrogramlevels,N.B. Khedekar, H.S. Sharma, S.G. tiarathe, H.C. Jain,Paper No. RA-09,Ibid.
56. Studies of controlled potential coulometric determination of plutoniuain mixed oxide samples,U.M. Kasar, V.B. Sagar, A.R. Joshi, V.K. Bhargava,Paper No. RA-24, Ibid.
57. Determination of sodium in cryolite,B.N. Patil, V. Shivarudrappa, S.G. Marathe, H.C. Jain,Paper No. RA-30,Ibid.
58. Alpha spectrometry for the determination cf 234u/238M r ati 0 in uraniumsamples,S.K. Aggarwal.P.M. Shah, R.K. Duggal, H.C. Jain, Paper No. RA-30, Ibid.
59. A comparative study of 239Pu, 2 3 8Pu and 2 3 3U spikes for determining Puconcentration,S.K. Aggarwal, R.K. Duggal, P.M. Shah, H.C. Jain, Paper No. RA-31, Ibid.
60. A new spectrophotometic method for the determination of nicroamountsof uranium,V.K. Bhargava, D.M. Naronha and J. Sharma, Paper No. RA-05, Ibid.
61. Determination of alpha specific activity and concentration of Pu indissolver solution of low burnup fuels by alpha spectrometry,G.Chourasiya, (/.A. Raman, P.A. Ramasubrananian, H.C. JainPaper No. RA-34, Ibid.
62. Chemistry of Nuclear Fuels.D.D. Sood,Invited talk at the 25th Annual Convention of Chemistry, Calcutta,1988.
63. Ion exchange in nuclear technology: some aspects.S.K. Patil.Invited talks, Ibid.
64. Synergic extraction of Pu(VI) by mixtures of HD2EHP and TOPO fromperchloric acid,K.V. Chetty, P.M. Mapara, R. Swarup, V.V. Ramakrishna, Ibid.
65. Synthesis of (U,Ce)C microspheres containing 20% Ce» by sol-gel process,S.K. Mukerjee, J.V. Dehadraya, Y.R. Bamankar, V.N. Vaidya, D.D. Sood,Ibid.
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66. Determination of uranium in presence of iron by controlled potentialcoulometry using platinum working electrode,U.M. Kasar, A.R. Joshi and C.K. Sivaramakrishnan,Ibid.
67. XRF analysis methods for actinide elements in nuclear fuels,N.C. Jayadevan,National workshop on X-ray emission spectrometry,lGCAR.Kalpakkarat1988).
68. X-ray diffraction study of the phases in K-Ba-U-0 system,A.K. Chadha, K.D. Singh Mudher and N.C. Jayadevan8th Annual Conference of Indian Council of Chemists, Tirupati(1988).
69. Influence of some parameters in the coulometric determination ofuranium by successive addition method,N. Gopinath, J.V. Kamat, H.S. Sharma, S.G. Marathe, H.C. JainPresented at the National seminar on electrode, CECR1,Karaikudi,Tamilnadu, July(1988l.
70. Studies on synergistic extraction of Pu(IV) by HTTA-DBDECMP mixturefrom perchloric acid medium,A.V. Jadhav, K. Raghuraman, K.A. Mathew, P.S. Nair, H.C. Jain,8th Annual Conference of Indian Council of Chemists, Tirupati(1988).
71. Effect of EDTA on ferrous-dichromate blank in the potentiometricdetermination of plutonium,S.P. Hasilkar, Keshav Chander and S.G. Marathe, Ibid.
72. Solvent extraction studiesof U(V1) and Pu(Vl) by D2EHPA and mixture ofD2EHPA and TOPO from sulphuric acid medium,K.V. Chetty, P.M. Mapara, R. Swarup, V.V. Ramakrishna, Ibid.
73. Preparation of copper sol by alkoxide route,R.V. Kamat, K.T. Pillai, N. Reghu, V.N. Vaidya, D.D. Sood,8th Annual Conference of Indian Council of Chemists, Tirupati(1988).
,. Synthesis of uranium mononitride microspheres by sol-gel process,S.K. Mukerjee, J.V. Dehadraya, Y.R. Bamankar, V.N. Vaidya, D.D. Sood,Ibid.
75. Chemical characterisation of plutonium fuels,D.D. Sood,Indo-German workshop on Techniques for Materials Characterisation,Hyderabad, 1988.
76. Experience in BARC on the preparation of gel microspheres of uranium,thorium and plutonium,D.D. Sood, V.N. Vaidya, An Invited talk at the International Symposiumon 'Nuclear fuel Fabrication-1988', Bombay, December 1988.
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77. Chemical quality control of nuclear fuels,S.K. Patil, Invited talk, Ibid.
78. Anubhati ke Indhan mein Rasayanaki ka yog,D.D. Sood,Seminar on ' Rasayanik Vigyan ke Lfbharte Kshitiz ', Bombay, Sept. 1968
79. Role of chemistry in nuclear technology,D.D. Sood,National Workshop on Nuclear and Radiation Chemistry, Poona,September(1988).
80. Sol-gel process for nuclear fuel fabrication - Experience at BARC,D.D.SoodInvited talk at the International Conference on ' Nuclear FuelFabrication ', BARC, Bombay 1988.
81. The role of chemistry in the fuel for nuclear power reactors,D.D. Sood,(Invited talk in Hindi) Hindi Symposium on Emerging Frontiers in
• Chemistry, Bombay(1988).
Published by : M. R. Balakrishnan Head, Library & Information Services DivisionBhabha Atomic Research Centre Bombay 400 085
