Analysis of reduction behavior of oxide fuels by lithium using UO2 and simulated material

Reduction of oxide fuels by lithium was studied by using both simulated materials and uranium dioxide. Fine powder of uranium dioxide (av. φ∼25μm) was reduced completely by lithium in a few hours at 650degC. Reduced uranium formed small aggregations by holding at 650degC even without the progress of reduction and existence of Li, Li2O. This aggregation was not observed at 550degC. Preliminary study for evaluating the reduction behavior of granular oxide was also carried out using TiO grains (4-10 mmφ). It was suggested that the diffusion of Li in Ti metal was the rate determining step. (author)