Electrolytic reduction of fast reactor MOX fuel at bench scale

A series of five electrolytic reduction runs with irradiated mixed uranium and plutonium oxide (MOX) fuel was performed with bench-scale equipment in a hot cell at Idaho National Laboratory. Select low and high burn-up MOX fuel elements were cut, and the fuel was removed from its cladding by crushing or oxidation. The fuel was sieved, and particles larger than 0.045 mm and less than 4 mm were loaded into one of four stainless steel mesh baskets, ranging from 53 to 56g of fuel per basket. Sixteen grams of fuel fines (less than 0.045 mm) were loaded into a sintered stainless steel basket. A molten salt solution of LiCl-1 wt% Li2O was prepared at 650 .deg. C. The reduction of MOX fuel in each basket was performed by submersing, a basket in the molten salt along side a platinum coil, as illustrated. An electrically conductive rod in the center of the basket and in contact with the fuel was configured as a cathode, and the platinum coil was configured as an anode across a power supply. A controlled current was passed through the anode and cathode, effecting the conversion of metal oxides to metal at the cathode and the simultaneous oxidation of oxygen ions in the salt to oxygen gas at the anode. Anode and cathode potentials relative to a Ni/NiO reference electrode were monitored along with current