Electrodeposition Characteristics of Uranium in Molten LiCl-KCl Eutectic and its Salt Distillation Behavior

Abstract

Electrorefining experiments with a crucial anode containing U, elemental rare earths; Gd, Nd and Ce or Nd2O3 were carried out in KCL-LiCL eutectic melt at 500°C. Partitioning behavior of the components according to the applied voltage or current was investigated at various initial U concentrations in a molten salt. Elemental REs concentrations in the cathode deposits increased as the applied voltage decreased at a low initial UCl3 concentration, while they were maintained at a very low level at a higher concentration than ∽6 wt%. Nd2O3 also shows a similar electrochemical behavior with the elemental REs. This means that rare earth oxides which are inherently incorporated in a U ingot can be partitioned during an electrorefining. The dependency of the applied current on the microstructure of the deposit was also discussed. From a variation of the cell resistance according to the rotation speed of the anode, a concentration polarization was detected below 3 wt% of UCl3 in the molten salt, but not above 6 wt%. Pure uranium ingot was obtained after a distillation of the salt from the deposit.