Quantitative calculations on the reoxidation behavior of oxide reduction system for pyroprocessing

Reoxidation reaction of metallic uranium in the oxide reduction system for pyroprocessing of used nuclear fuels is quantitatively investigated via calculating thermodynamic equilibrium compositions. The calculations consider three operating parameters; LiCl/U ratio, Li 2 O concentration, and excess metallic Li. The results suggest that decreasing LiCl/U ratio and Li 2 O concentration reduce the extent of the reoxidation reaction. The presence of excess metallic Li suppresses the reoxidation reaction more effectively; the calculated amount of reoxidized U from pure metallic U is merely 0.6% with 9 wt% (vs. Li 2 O) of excess Li. Excess Li can be synthesized in situ during the oxide reduction operation.