Porous UO₂sintered pellet for electroreduction process, and preparation method thereof

摘要

Porous UO2 sintered pellets to be fed into an electrolytic reduction process for the purpose of metallic nuclear fuel recovery, include one or more hollow spaces formed from the surfaces toward the interiors thereof. When the porous UO2 sintered pellets are used in the electrolytic reduction process, the efficiency increases.

主权项

1. A method for fabricating porous UO2 sintered pellets to be fed into an electrolytic reduction process for the purpose of metallic nuclear fuel recovery, the porous UO2 sintered pellets having one or more hollow spaces formed in a surface of the pellets, the one or more, hollow spaces extending inwardly from the surface toward interiors thereof, the method comprising the steps of:
forming a powder containing U3O8 by oxidizing spent nuclear fuel containing uranium dioxide (UO2) (step 1); compacting the powder formed in step 1 into green pellets with hollow spaces formed therein (step 2); fabricating UO2+x sintered pellets by sintering the porous U3O8 green pellets fabricated in step 2 at 1200 to 1600° C., in an atmospheric gas (step 3); and forming UO2 sintered pellets by cooling the UO2+x sintered pellets in step 3 to room temperature, and reducing the same at 1000 to 1400° C., in a reducing atmosphere (step 4).