Effect of Ce ions on MOX codeposition in oxide-electrowinning reprocessing

Abstract An experiment of MOX codeposition from U–Pu–Ce containing molten salt in oxide -electrowinning reprocessing was performed. Composition of O 2 /Cl 2 /Ar mixed gas, Ce concentration and U/Pu concentration in the salt were chosen as variable parameters. Ten tests were performed in this experiment. Current efficiency in each test was about 60–99%, and apparent dependence of the current efficiency on concentration of Ce in the salt was not seen in this experiment. Recovered MOX deposits contained about 5–19 wt% of Pu and 0.5–2 wt% of Ce. Concentration of Pu and Ce in the MOX deposit was influenced by O 2 /Cl 2 /Ar mixed gas composition and Ce concentration in the salt, respectively. Microphotographs of cross-section show that the MOX deposit was a complex of small columnar crystals. Some parts of the cross-section were analyzed by EPMA. These results indicated that a U rich region (concentration of U: about 80 wt%) exists in central part of the crystal and Pu rich regions (concentration of Pu: about 80 wt%) scatter on its surface and Ce is distributed rather uniformly.