Molten Salt Assisted Electrochemical Separation of Spent Fuel Surrogates by Partial Direct Reduction and Selective Anodic Dissolution

Pyrometallurgical reprocessing of spent nuclear fuels has experienced growing interest in recent years as it presents a desirable and proliferation resistant separation process capable of significantly reducing volumes of high level waste (HLW). Additionally, the use of molten salts in pyro-reprocessing is seen as forward compatible with the new GEN IV fast neutron nuclear reactors. In this work, the ability to selectively partition spent fuel surrogate species in solid phase by molten salt electrochemistry was assessed in a proof of concept experiment by the use of the 2NiO-CeO₂ binary. In a three electrode cell using potentiostatic electrolysis it was found that close to 80% of the Ni presence in the surface of the precursor was removed following a partial direct reduction of NiO by the FFC Cambridge Process, followed by anodic dissolution to remove the metallic Ni phase. The mixture of more analogous electrochemical surrogates ZrO₂ and CeO₂ to that of UO₂ and PuO₂ were then assessed to further confirm the application of this novel recycling technology.