Electrochemical reduction of MOX pellets in molten lithium chloride based on a practical operating condition

Kurata, Masaki* ; Yahagi, Noboru*; Kitawaki, Shinichi ; Nakayoshi, Akira  ; Fukushima, Mineo

Electrochemical reduction of MOX pellets was performed by using the pellets as a cathode, directly in a molten LiCl bath. Reduction was completed for 15 hours. This value compares closely to the previous values for UO particles or powders. Current efficiency was varied at 60%, which is slightly higher than in the previous one. The lower density of MOX allows better diffusion of the molten salt into the pellet and contributes to efficient electrolysis. After electro reduction, the U and Pu concentrations in the melt weren't detected. Although a small amount of Am was dissolved in the melt and gradually accumulated, the amount was 1% with respect to the initial amount. The oxygen concentration in the molten salt decreased gradually during electrolysis. These variations in the salt hardly affected the current efficiency and the actinide recovery ratio. These observations indicate that the electrochemical reduction of MOX pellets is applicable to industrial processes.