The Portsmouth Gaseous Diffusion Plant

More than 2,400 workers are employed at the site, making it one of the largest employment drivers in the region. It consists of three main areas: the gaseous diffusion plant, centrifuge facilities and depleted uranium hexafluoride conversion (DUF6) facility.

The largest of the three areas is the gaseous diffusion plant, which consists of three main process buildings (X-333, X-330, and X-326) housing the gaseous diffusion process equipment, as well as hundreds of supporting facilities. The various support facilities include those needed for feed and transfer operations, maintenance, steam generation, chemical cleaning, decontamination, process heat removal, water supply, water storage, water distribution, electrical power distribution, and administration.

Most of the buildings are within an approximate 1,000-acre industrialized area that lies within the Perimeter Road. The remaining property outside of Perimeter Road is used for a variety of purposes, including a water treatment plant, sediment ponds, closed landfills, cylinder storage yards, open fields, and forested buffer areas.

Portsmouth Site regional map

The Portsmouth site is located in south central Ohio.


tour book cover

Tour Book cover

The United States Department of Energy (DOE) provides opportunities for members of the public to tour the Portsmouth Gaseous Diffusion Plant site on select dates. The bus tour circles the plant’s perimeter with one stop to visit inside the Plant Control Facility, the hub of the gaseous diffusion plant. The tour involves minimal walking, just a short distance from the bus to the building.  Participants must be U.S. citizens 18 years of age or older.

The tours provide a close-up view of the former uranium enrichment facilities before they are addressed under the Decontamination & Decommissioning (D&D) Project, and a unique opportunity to become oriented with the history of the plant, its current activities and its future missions.

For more information or to register for a tour email Jack Williams at, or call (740) 897-2964.