Separation and Recovery of Uranium Metal from Spent Light Water Reactor Fuel Via Electrolytic Reduction and Electrorefining

A series of bench-scale experiments was performed in a hot cell at Idaho National Laboratory to demonstrate the separation and recovery of uranium metal from spent light water reactor (LWR) fuel. The experiments involved crushing spent LWR fuel to particulate and separating it from its cladding. Oxide fuel particulate was then converted to metal in a series of six electrolytic reduction runs performed in succession with a single salt loading of molten LiCl-1 wt% Li₂O at 650°C. Analysis of salt samples following the series of electrolytic reduction runs identified the partitioning of select fission products from the spent fuel to the molten salt electrolyte. The extent of metal oxide conversion in the posttest fuel was also quantified, including a 99.7% conversion of uranium oxide to metal. Uranium metal was then separated from the reduced LWR fuel in a series of six electrorefining runs performed in succession with a single salt loading of molten LiCl-KCl-UCl₃ at 500°C. Analysis of salt samples following the series of electrorefining runs identified additional partitioning of fission products into the molten salt electrolyte. Analyses of the separated uranium metal were performed, and its decontamination factors were determined.