Disposition Pathways: Immobilization

Approximately one-third of the surplus U.S. plutonium is in the form of impure metal, oxides and reactor fuel, which are unsuitable for MOX use without extensive purification. To dispose of this material, we plan on using a “can-in-canister” approach for immobilization. Under this approach, this plutonium would be converted to oxide, immobilized with ceramic material, and placed in sealed steel cans, which would then be arrayed within large canisters. The canisters containing the cans of immobilized plutonium would then be filled with vitrified high-level radioactive waste. The heavy canisters of vitrified high-level radioactive waste provide a barrier that increases the proliferation resistance. Subsequently, the canisters would be disposed of in a planned geologic repository, pursuant to the Nuclear Waste Policy Act. While the United States has experience with immobilizing high-level wastes, the technological aspects of how to immobilize weapons plutonium on an industrial scale need to be resolved.