LAUSR

Abstract Direct electrolytic reduction (DER) of UO 2 utilizes a molten LiCl-Li 2 O electrolyte operating at 650 °C.Productive processes at the cathode are UO 2 and Li 2 O reduction (followed by metallothermic reduction of UO 2 by Li metal). Non-productive reduction current has been observed that could be attributed to impurities produced from interaction of the salt with water. Cyclic voltammetry (CV) scans of molten mixtures of LiCl containing Li 2 O, LiOH, and/or Li 2 O 2 indicate that LiOH is the primary cause of reduction current preceding UO 2 and Li 2 O reduction. LiOH reduction appears as a broad soluble-soluble transition and forms a pre-reduction plateau characteristic of micro-electrode reactions. Electrochemical response to LiOH in the salt is reduced with addition of Li 0 , providing a practical approach to eliminating LiOH from LiCl-Li 2 O salt before the DER process. Generation of H 2 gas was detected while heating Li 0 with LiCl-Li 2 O-LiOH, consistent with a reaction mechanism where LiOH reduction causes formation of Li 2 O and H 2 .