y12

Y-12 National Security Complex is a United States Department of Energy national security facility located in Oak Ridge, Tennessee. It originated during World War II as part of the Manhattan Project, where it housed calutrons—electromagnetic separators used to enrich uranium-235. After the war, Y-12’s mission shifted toward production and maintenance of components for the U.S. nuclear weapons stockpile and secure storage of nuclear materials.

Today, Y-12 conducts uranium processing and fabrication, material characterization, and surveillance of weapons components in support of national defense and nonproliferation objectives. The site is notable for its storage facilities for highly enriched uranium, including the Highly Enriched Uranium Materials Facility (HEUMF), opened in the 2010s as a modern, secure storage complex. Y-12’s operations emphasize safety, security, and environmental stewardship in handling sensitive nuclear materials.

Management of the site is provided under the National Nuclear Security Administration. The Y-12 complex is operated by Consolidated Nuclear Security, a partnership led by Lockheed Martin, Jacobs Engineering, and Bechtel. The facility employs thousands of workers and collaborates with other DOE offices, national laboratories, and defense programs to maintain the security and reliability of the U.S. nuclear weapons stockpile and related nonproliferation efforts.