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Title: Cerium-promoted dissolution of PuO/sub 2/ and PuO/sub 2/--UO/sub 2/ in nitric acid

Technical Report ·
DOI:https://doi.org/10.2172/7287768· OSTI ID:7287768

Several experiments were run to determine the feasibility of using cerium as an alternative to fluoride in promoting rapid dissolution of difficultly soluble PuO/sub 2/ in nitric acid. Results show that Ce/sup 4 +/, but not Ce/sup 3 +/, promotes dissolution with a maximum rate in boiling 4M HNO/sub 3/. Other strong oxidants, including ozone, permanganate, and persulfate, were tested but were shown to be ineffective. During dissolution, the Ce/sup 4 +/ is reduced to Ce/sup 3 +/, which must be reoxidized electrolytically or with ozone. Ruthenium also reduces the Ce/sup 4 +/ catalytically, being oxidized to the volatile RuO/sub 4/. Thus successful application to dissolution of irradiated fuel residues would require modification of the equipment or procedures in such a way as to encourage complete volatilization of ruthenium from the dissolver system. However, application of this method to the treatment of plutonium appears promising.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
7287768
Report Number(s):
ORNL/TM-4716
Country of Publication:
United States
Language:
English