The Portsmouth plant enriched uranium from 1954 until 2001 through a process called gaseous diffusion.

The Portsmouth Gaseous Diffusion Plant operated from 1954 to 2001. Located in Pike County, Ohio, the plant occupies about 1,200 acres of the 3,777-acre federally-owned Portsmouth Site. The plant was one of three large gaseous diffusion plants in the United States initially constructed to produce enriched uranium to support the nation’s nuclear weapons program and, in later years, enriched uranium used by commercial nuclear reactors. After the Cold War, weapons-grade uranium enrichment was suspended and production facilities were leased to the private sector. In 2001, enrichment operations were discontinued at the site. 

DOE's Office of Environmental Management began its environmental cleanup program at the site in 1989 and the effort continues today in cooperation with the U.S. and Ohio Environmental Protection Agencies.  Decontamination and decommissioning (D&D) of the plant commenced in 2011 and is ongoing.  



Portsmouth Excavations a Win for Waste Disposition, Cleanup, Site Reuse
August 31, 2021
Work is underway at EM’s Portsmouth Site on the first of five legacy groundwater plumes to be excavated for soil needed in the newly constructed On-Site Waste Disposal Facility (OSWDF).
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EM Building New Road to Deliver Portsmouth Demolition Debris to On-Site Disposal
March 30, 2021
Crews are working to finish construction of a dedicated road at EM’s Portsmouth Site that will be used to haul demolition material to the new On-Site Waste Disposal Facility (OSWDF).
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Oak Ridge, WIPP, Los Alamos, and PPPO Focus on Cleanup Progress
March 17, 2021
EM sites provided updates on their cleanup progress during individual sessions at Waste Management Symposia 2021.
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Portsmouth Site Launches New Science Education Program for Students
March 2, 2021
EM’s Portsmouth Site has launched a new education program aimed at getting local students to start thinking about careers in STEAM.
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