An experimental study on an electrochemical reduction of an oxide mixture in the advanced spent-fuel conditioning process

Abstract

An electrochemical reduction of a mixture of metal oxides was conducted in a LiCl molten salt containing 3 wt% Li2O at 650°C. 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 Li 2O 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.