Oak Ridge Thermal Diffusion Plant

The S-50 Plant at Oak Ridge was constructed in 1944 to enrich uranium feed material for the Y-12 electromagnetic facility using a liquid thermal diffusion process. The process was originally developed at the Naval Research Laboratory in Washington, DC, and tested on a pilot plant level at the Philadelphia Naval Shipyard. Located near the K-25 gaseous diffusion facility, the S-50 Plant operated for a limited period during 1944-1945. The plant was closed in September 1945 because the thermal diffusion process was not as efficient as the gaseous diffusion.
The S-50 plant was reopened in 1946 as part of the joint Air Force/AEC project to investigate the possibility of developing a nuclear-powered airplane. This project, known as Nuclear Energy for the Propulsion of Aircraft (NEPA), was housed at S-50 and the contractor was the Fairchild Engine and Aircraft Corporation. Fairchild’s NEPA Division at S-50 conducted a number of experiments involving beryllium powder during the time period 1946-1951.

Alternative Names

• S-50

Type of Facility

• Department of Energy

Covered by EEOICPA

• Part B and Part E

EEOICPA Covered Years

• 1944-1951

DOE

• DOE Facility List by Name

DOL

• Tracking your DOL Claim Status
• Advisory Board on Toxic Substances and Worker Health
• Ombudsman’s Office
• Resource Center
• DOL Case and Claim Statistics
• Bulletin 07-08: Processing Claims for S-50 Oak Ridge Thermal Diffusion Plant Special Exposure Cohort (SEC) Class, July 9, 1944 through December 31, 1951

NIOSH

• FAQs About Your Case
• Advisory Board on Radiation and Worker Health
• NIOSH Case Statistics
• Special Exposure Cohort Status Table
  • Petition 060: “Employees of the Department of Energy predecessor agencies and their contractors or subcontractors who were monitored or should have been monitored while working at S-50 Oak Ridge Thermal Diffusion Plant (S-50) for a number of work days aggregating at least 250 work days during the period from July 9, 1944 through December 31, 1951, or in combination with work days within the parameters established for one or more other classes of employees in the SEC.”
• Work Site Information