Study of the Electrolytic Reduction of Uranium Oxide in LiCl-Li2O Molten Salts with an Integrated Cathode Assembly

The electrolytic reduction of uranium oxide in a LiCl-Li2O molten salt system has been studied in a 10 g U3O3 /batch-scale experimental apparatus with an integrated cathode assembly at 650 .deg. C. The integrated cathode assembly consists of an electric conductor, the uranium oxide to be reduced and the membrane for loading the uranium oxide. From the cyclic voltammograms for the LiCl-3 wt% Li3O system and the U3O3-LiCl-3 wt% Li2O system according to the materials of the membrane in the cathode assembly, the mechanisms of the predominant reduction reactions in the electrolytic reactor cell were to be understood; direct and indirect electrolytic reduction of uranium oxide. Direct and indirect electrolytic reductions have been performed with the integrated cathode assembly. Using the 325-mesh stainless steel screen the uranium oxide failed to be reduced to uranium metal by a direct and indirect electrolytic reduction because of a low current efficiency and with the porous magnesia membrane the uranium oxide was reduced successfully to uranium metal by an indirect electrolytic reduction because of a high current efficiency.