Journal of Nuclear Fuel Cycle and Waste Technology

Electrowinning process in pyroprocessing recovers U (uranium) and TRU (Trans Uranium) elements simultaneously from spent fuels using a liquid cadmium cathode (LCC). When the solubility limit of U deposits over 2.35wt% in Cd, U dendrites were formed on the LCC surface during the electrodeposition at 500℃. Due to the high surface area of dendritic U, the deposits were not submerged into the liquid cadmium pool but grow out of the LCC crucible. Since the U dendrites act as a solid cathode, it prevents the co-deposition of U and TRUs. In this study, the electrodeposition of U onto a LCC was carried out at 440 and 500℃ to compare the morphology and component of U deposits. The U deposits at 440℃ have a specific shape and were stacked regularly at the center of the LCC pool, while the U dendrites (i.e., α-phase) at 500℃ were grow out of the LCC crucible. Through the microscopic observation and XRD analysis, the electrodeposits at 440℃, which have a round shape, were identified as an intermetallic compound such as UCd11. It can be concluded that the LCC electrowinning operation at 440℃ achieves the co-recovery of U and TRU without the formation of U dendrites.

Keywords

Electrowinning,LCC(Liquid Cadmium Cathode),U dendrite,Intermetallic compound