AN EXPERIMENTAL STUDY ON AN ELECTROCHEMICAL REDUCTION OF AN OXIDE MIXTURE IN THE ADVANCED SPENT-FUEL CONDITIONING PROCESS

An electrochemical reduction of a mixture of metal oxides was conducted in a LiCl molten salt containing 3 wt% Li₂O at 650℃. The oxide reduction was carried out by applying a current to an electrolysis cell, and the Li₂O concentration was analyzed during each run. The concentration of Li₂O in the electrolyte bulk phase gradually decreases according to Faraday’s law due to a slow diffusion of the O₂- ions. A hindrance effect of the unreduced metal oxides was observed for the reduction of the uranium oxide. Cs, Sr, and Ba of high heat-load fission products were diffused into and accumulated in the salt phase as predicted with thermodynamic consideration.