AQUEOUS PROCESSES FOR DISSOLUTION OF URANIUM-MOLYBDENUM ALLOY REACTOR FUEL ELEMENTS [report]

L M Ferris
1961 unpublished
T h i s r o p o t t w a s p r e p u i e d u s u n account of G o v u r n m e n t s p o n s o r e d work. N e j t h c r t h e l l n i t c d S t a t e s , n o r t/,e C o r n i n i s s i o~, nor o r~y p c r s o n o c t i n g on b e h a l f o f t h e C o m m i s s i o n : A . M a k e s o n y w o r i o n t y or r e p r e s e n t a t i o n , e x p r e s s e d or implked, w i t h r e s p e c t t o t h e o c c u r a c y , c o m p l c t o n c s s , 01 v s c f u i n r s s of t h e i n ( o r i n o t i o n
more » ... ( o r i n o t i o n c o n t a i n e d ~n t h i s report, o r t h a t the u s e of oily i n f o r m a t i o n , a p p o i o t v s , method, o r p r o c e s s d n s c l o s e d in thts r e p o r t rnoy n o t i n f r i n g e p r i v a t e l y o w n e d i i q h t s ; or A s s v m c s n n y t n i a r n i o t i o n , n p p u r n t u r , method, or p r o c e s s d a s c l o s e d i n thds repost. 5 . o n y liabilities w i t h r a s p e c t t o t h e use of, o r for d o n i o g c r r e s u l t i n g f r o m t h e u s e o! A s u s e d i n t h e " h o v e , " p c r 5 o n acting o i l bchulf of t h e C u w m i s s i o n " i n c l u d e s a n y e m p l o y e e or c o n t r n c t o r of t h e C o~r~w s~~o n , or cnrployoc o f s u c h c o i i t r o c t n r , to tlic e x t e n t t h o t SUCII e m p l o y e e or c o n t r a c t o r of t h e C~n i i i i i s s~~n , 0 1 crnpluyec o f siich contcnctor prepares, d i s s c m i n o t e s , or p r o v i d e r O C C O S P to, u n y ~n f o r m o t i o i i p u i s u o n r t o lhfs e m p l o y m e n t or contract w i t h t h e C o m m i s s i o n , or his e m p l o y m e n t w i t h s u c h c o n t r u c t o r . ABSTRACT Methods for dissolving unirradiated uranium-molybdenum alloy reactor fuels in nitric acid, nitric acid-ferric nitrate,and nitric acid-phosphoric acid solutions were studied on a laboratory scale. the results propose dissolution of alloys containing 376 molybdenum in boiling 6 M HNO 3 to 4 Min nitric acid. and recovered in a conventional Purex-type tributyl phosphate solvent extraction process. in boiling 11 M HNO oxide, which carries 5-lO$ of the uranium, is removed by centrifugation and the acidity of the supernatant solution adjusted to allow recovery of the uranium by Purex-type solvent extraction procedures. The uranium carried by the molybdic oxide is recovered after the MOO warm 5 M -NaOH. Less than 0.1% of the uranium is solubilized during the caustic dissolution. Flowsheets based on to yield stable solutions that are 0.6 Min uranium and -3 The uranium can then be easily decontaminated Alloys containing 10% molybdenum would be dissolved allowing molybdic oxide to precipitate. The molybdic -3' is dissolved in 3 Alternative methods investigated involve dissolution in nitric acid containing 0.5 to 1 Mferric nitrate to complex the molybdenum. techniques lead to undesirably large volumes of high-level solvent extraction waste solutions. Phosphate ion is also effective in complexing molybdenum; however, its use in the dissolvent would be purposeless since it must be complexed with iron during solvent extraction. Rates of reaction of the various a l l o y s and the solubility of These molybdic oxide were determined in nitric acid, nitric acid-ferric nitrate, and nitric acid-phosphoric acid solutions. Y .& i J .
doi:10.2172/4022353 fatcat:pbqi434al5gp7iiteh2hykfm74