U-233 GRADED SAFEGUARD REQUIREMENTS

The Department of Energy (DOE) is currently storing Uranium-233 (U-233) material, which has been determined to be excess material. Work is being planned to convert the U-233 into a form that can be more easily and inexpensively stored. Chemical processing will also be used to extract the Th-229 (U-233 decay product) to support cancer research and treatment. The U-233 materials will potentially be mixed with varying quantities of depleted or natural uranium in order to “downblend” the U-233 to a level of reduced safeguards and security requirements (e.g., DOE Manual 474-1.1A Table I-4, Graded Safeguards: Category IV, Attractiveness Level E). The DOE U-233 safeguards requirements were evaluated to determine if a domestic policy basis could be established to reduce the safeguard requirements on U-233 by treating it on an isotopic basis (as is currently done for U-235). The methodology, policy basis, security implications, and lessons learned will be discussed.