The Melt-Dilute Treatment Disposition Option for 233U

The U.S. Department of Energy has initiated a program for disposition of surplus weapons-usable fissile materials by making them inaccessible and unattractive for use in nuclear weapons. The program supports both the U.S. arms-control and nonproliferation policies of the government. Uranium-233 is a weapons-usable material like weapons-grade plutonium and high-enriched uranium. Oak Ridge has 233U stored in oxide form in stainless steel canisters, and they need to place the material in long-term safe storage that meets U.S. policies in a cost-effective manner. A proposed option for treatment of this material is the Melt-Dilute (MD) technology, now under developed at Savannah River Site for aluminum-base spent nuclear fuel. Using the MD process, unirradiated fissile material is first melted in an induction furnace and depleted uranium is added to dilute the 233U or 235U content to acceptable levels. Aluminum is added to control the alloy composition. After solidification the ingot is removed from the furnace and put into a storage canister for eventual shipment to a geologic repository