KNOXVILLE, Tenn. (WATE) — Three 1940s-era buildings on the Y-12 National Security Complex campus in Oak Ridge are up next for removal. All three will be worked on simultaneously, according to the Department of Energy’s Office of Emergency Management.

Contractor UCOR and its crews are deactivating Building 9201-2, also known as Alpha-2; Building 9401-1, aka the old steam plant; and Building 9213, aka the old criticality experiment laboratory after transitioning them to a “cold and dark” status in which all potential hazardous energy sources are isolated.

“These crews were part of the team that completed the first-in-the-world removal of a gaseous diffusion complex last year, and they also completed demolition prep for the Biology Complex at Y-12,” UCOR Oak Ridge Reservation environmental cleanup manager Dan Macias said. “The skills and training these workers bring to each project allow them to successfully complete our work safely and efficiently.”

More than 50% of the facilities throughout the National Nuclear Security Administration complex, which includes Y-12, are more than 40 years old, and 30% of them were built in the Manhattan Project age.

Alpha-2 is the largest building where deactivation is underway. The three-story, 325,000-square-foot facility was constructed to enrich uranium using an electromagnetic separation process, which ended in 1946. The facility was used for a variety of other missions until it was shut down in the 1990s.

The old steam plant is a single-story, 13,454-square-foot facility built-in 1943. This building has had multiple uses over the years. In the 1960s and 1970s, it was used to develop a dipping process for uranium parts. Subsequently, Oak Ridge National Laboratory used the facility to test fuels, and it later became a maintenance and storage facility.

The old criticality experiment laboratory was built in 1949. The two-story, 24,000-square-foot facility was home to more than 9,700 experiments from 1950 until 1961. It was later used to support ORNL’s High-Flux Isotope Reactor program. The building has been closed since 1992.