Systems and methods are provided for reducing the storage time of spent nuclear fuel. In one embodiment, a method is provided that includes providing a sample of spent nuclear fuel and irradiating the spent nuclear fuel with substantially collimated gamma ray photons having energy levels of about 10 MeV to about 15 MeV for a predetermined time period to initiate a photofission reaction in the remaining fertile fissile material in the spent nuclear fuel.

A method for fabricating porous UO.sub.2 sintered pellets to be fed into the electrolytic reduction process for the purpose of metallic nuclear fuel recovery is provided, which includes forming a powder containing U.sub.3O.sub.8 by oxidizing spent nuclear fuel containing uranium dioxide (UO.sub.2) (step 1), fabricating green pellets by compacting the powder formed in step 1 (step 2), fabricating UO.sub.2+x sintered pellets by sintering the porous U.sub.3O.sub.8 green pellets fabricated in step 2 at 1200 to 1600 C., in an atmospheric gas (step 3), and forming UO.sub.2 sintered pellets by cooling the UO.sub.2+x sintered pellets to room temperature, and reduction the same at 1000 to 1400 C., in a reducing atmosphere (step 4).

A method for fabricating porous UO.sub.2 sintered pellets to be fed into the electrolytic reduction process for the purpose of metallic nuclear fuel recovery is provided, which includes forming a powder containing U.sub.3O.sub.8 by oxidizing spent nuclear fuel containing uranium dioxide (UO.sub.2) (step 1), fabricating green pellets by compacting the powder formed in step 1 (step 2), fabricating UO.sub.2+x sintered pellets by sintering the porous U.sub.3O.sub.8 green pellets fabricated in step 2 at 1200 to 1600 C., in an atmospheric gas (step 3), and forming UO.sub.2 sintered pellets by cooling the UO.sub.2+x sintered pellets to room temperature, and reduction the same at 1000 to 1400 C., in a reducing atmosphere (step 4).