Highly enhanced reduction of rare earth oxides in simulated oxide fuel in Li2O[sbnd]LiCl salt using lithium metal

Abstract

The reducibility of rare earth oxides (REOs) in electrolytic reduction of nuclear used oxide fuel is poor as a result of their high oxygen affinity and thermodynamic stability. We show that the reduction of REOs to rare earth metals in Li2OLiCl salt can be enhanced significantly by using lithium metal. Specifically, REOs in the fuel are reduced to a high extent in the electrolytic reduction of simulated oxide fuel in 1.0-wt% Li2OLiCl salt following the application of electrical charge in order to induce the production of Li metal. We also demonstrate that the low reduction levels of REOs in reduced simulated fuel with high uranium metal content, which is produced through another electrolytic reduction run, can be increased by the immersion of the reduced simulated fuel in fresh LiCl salt containing Li metal at 0.3 wt%.