Oxidative dissolution of spent nuclear fuel in aqueous alkaline solutions – an alternative to the PUREX process?

I&EC 111

Shane M. Peper1, Wolfgang H Runde1, Stephanie E. Field1, Ralph A. Zehnder1, Lia F. Brodnax1, William J. Crooks2, and Gordon D Jarvinen2. (1) C-INC, Los Alamos National Laboratory, MS J-514, Los Alamos, NM 87544, (2) NMT-11, Los Alamos National Lab, E546 LANL, Los Alamos, NM 87544
As an alternative to acidic reprocessing of spent nuclear fuel the oxidative dissolution of UO2 into aqueous alkaline solutions and subsequent separation of fission products is considered. A series of dissolution studies have been performed on UO2 and U3O8 in aqueous alkaline solutions applying various oxidants. Among the oxidative agents commonly used to transform low-valence actinides into their higher oxidation states H2O2 has proven to be the most effective in basic media. Consequently, we investigated the dissolution of UO2 and U3O8 in NaOH-H2O2 and Na2CO3-H2O2 solutions and determined the dissolution kinetics as a function of peroxide and hydroxide (carbonate) concentrations. The methods to remove the fission products, i.e. Cs, Sr, and Ba, from alkaline solutions will be evaluated based upon their decontamination factors. We will discuss the feasibility of using chemically oxidizing alkaline solutions as an alternative spent nuclear fuel reprocessing method based on results from experimental quantitative investigations.