Impact of Ag on Electrochemical Recovery of UO2 in Molten LiCl-KCl Salt

To investigate the effect of fission element Ag on the electrochemical recovery of UO2, the electroreduction mechanisms of Ag+ and UO22+ kinetic property of Ag+/Ag couple were first studied on W electrode by different electrochemical techniques. The electrode reactions of Ag+ and UO22+ were found to be one-step and two-step reduction processes, respectively. The exchange current density of Ag+/ Ag couple was estimated to be 0.0431 similar to 0.0727 A cm(-2) in the temperature range of 723 similar to 798 K by LP technique, and its activation energy was evaluated to be 33.91 kJ mol(-1). The deposition products obtained by constant potential electrolysis (CPE) were characterized by XRD and SEM-EDS, which showed the formed Ag and UO2 having pine-branch and micron-scale polyhedral structure, respectively. The influence of Ag+ on the electrochemical behavior of UO22+ and morphology of UO2 were studied. The deposition potential of Ag+ was close to that of UO2+ to UO2. The changes of Ag+ concentration and scan rate had no effect on the electroreduction mechanism of 2 CPE was conducted, and the result indicated that UO2 and Ag could be co-deposited. The deposited Ag could change the morphology of recovered UO2. (c) 2023 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited. [DOI: 10.1149/1945-7111/ acf900]