Nuclear fuel reprocessing and actinide chemistry

Reprocessing of spent nuclear fuels from PWR type reactors is supposed to separate TRU and fission products from recovered U and Pu for future reutilization. Besides Purex process combined with Chop and Leach, dry electrolytic processes of molten metal or oxide fuels have been already proposed. This paper summarizes the features of TRU-related chemistry in each reprocessing method and compares their merits and demerits with each other. The oxidation state of U, Pu, Np, and Am among others in nitric acid solution, molten salts (LiCl-KCl, NaCl-2CsCl), and metallic Bi in presence or absence of such oxidizing agents as oxygen or chlorine is used to classify chemical reactions to be used for mutual separation. Excess free energy and enthalpy changes of lanthanide and actinide elements in liquid metals are systematically examined and proposed to further development of this research. (S. Ohno)