Reactor and Material Supply

Y-12 has processed highly enriched uranium for more than 60 years in support of the nation’s defense. The end of the Cold War and ensuing strategic arms control treaties have resulted in an excess of HEU materials. In 1994, approximately 174 metric tons of weapons-usable HEU was declared surplus to defense needs.

The HEU disposition program was established to make the surplus HEU unsuitable for use in weapons by blending it down to low-enriched uranium and to recover the economic value of the materials to the extent practical. In 2005, the Secretary of Energy announced that an additional 200 metric tons of HEU would be removed from further use as fissile material in U.S. nuclear weapons. Approximately 20 metric tons of this material will be downblended to LEU for eventual use in power reactors, research reactors or related research.

Managing the downblending of these materials is the responsibility of the Reactor and Material Supply group at Y-12. R&MS receives its funding through NNSA’s Office of Fissile Materials Disposition. While Y-12 has processed HEU over many decades for defense needs, the majority of the downblending for non-defense needs is being performed by commercial facilities, with a portion at government facilities.

Over the past decade, NNSA’s Surplus U.S. HEU Disposition Program has eliminated 134 metric tons of surplus U.S. weapons-usable HEU by downblending it to LEU for use in power and research reactors in the United States and abroad. Several major downblending projects have been used to eliminate the proliferation potential of the 134 metric tons of HEU. These projects include disposition through the U.S. Enrichment Corporation, the Tennessee Valley Authority, the Reliable Fuel Supply and its successor the American Assured Fuel Supply, and the Mixed Oxide LEU Backup Inventory project. Additional HEU material is being downblended for research reactors around the world.