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Preparation of Curium-Americium Oxide Microspheres by Resin-Bead Loading F. R. CHATTIN, D. E . BENKER, M . H. L L O Y D , P. B. R. G. ROSS, and J. T. WIGGINS
ORR,
Oak Ridge National Laboratory, Oak Ridge, T N 37830
A resin-bead l o a d i n g and c a l c i n a t i o n technique developed at the Transuranium P r o c e s s i n g P l a n t (TRU) of the Oak Ridge N a t i o n a l Laboratory (ORNL) is used r o u t i n e l y f o r producing u n i form p a r t i c l e s of curium-americium oxide in the s i z e range d e s i r e d f o r the f a b r i c a t i o n of t a r g e t s f o r i r r a d i a t i o n in the High Flux Isotope Reactor (HFIR). TRU is the storage, product i o n , and d i s t r i b u t i o n center f o r the heavy-element research program of the U. S. Department of Energy. Target rods are remotely f a b r i c a t e d at TRU, i r r a d i a t e d in the HFIR, and then processed c h e m i c a l l y at TRU f o r the s e p a r a t i o n and p u r i f i c a t i o n o f the heavy a c t i n i d e elements. Berkelium, c a l i f o r n i u m , e i n s t e i n i u m , and fermium are d i s t r i b u t e d t o r e s e a r c h e r s . Curium and americium t h a t are recovered during the chemical p r o c e s s i n g are r e f a b r i c a t e d i n t o t a r g e t s f o r a d d i t i o n a l i r r a d i a t i o n . About 200 g of curium-americium oxide are produced annually f o r use in f a b r i c a t i n g HFIR t a r g e t s . D e t a i l e d d e s c r i p t i o n s of TRU and the o v e r a l l production program have been p u b l i s h e d p r e v i o u s l y (1,2, 3,4,5), and a summary of the program is presented in another paper at this symposium (6). A HFIR t a r g e t is a 9.4-mm-diam by 0.89-m-long aluminum rod encased in a c y l i n d r i c a l aluminum tube which serves t o channel the flow of c o o l i n g water in the r e a c t o r . The c e n t r a l t a r g e t rod contains some end hardware p l u s t h i r t y - f i v e 6.3-mm-diam by 14-mm-long p e l l e t s that c o n t a i n a blend of curium-americium oxide (~15% by volume) and aluminum powder encased in an aluminum j a c k e t . A p e l l e t is made by p l a c i n g a weighed amount of blended a c t i n i d e oxide—aluminum powder in a l i n e r of aluminum t u b i n g that has had one end c l o s e d with aluminum powder pressed t o t h e o r e t i c a l d e n s i t y . Then c l e a n aluminum powder is added t o form a top cap, and the p e l l e t is cold-pressed in a p e l l e t d i e . The s i z e of the curium-americium oxide p a r t i c l e s is an important c r i t e r i o n in the production of HFIR t a r g e t s because of the r e l a t i v e l y high oxide content in the blend. The oxide part i c l e s must be uniformly d i s p e r s e d in the aluminum p e l l e t s , and the pressed p e l l e t s must have a continuous aluminum phase t o 0097-6156/81/0161-0173$05.00/0 © 1981 American Chemical Society
Navratil and Schulz; Transplutonium Elements—Production and Recovery ACS Symposium Series; American Chemical Society: Washington, DC, 1981.
TRANSPLUTONIUM
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174
ELEMENTS
ensure adequate heat t r a n s f e r during i r r a d i a t i o n . When oxide p a r t i c l e s at some s i z e smaller than 10 ym in diameter are mixed with -325 mesh (
