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U.S. Department of Energy Releases Final Environmental Assessment for Molten Chloride Reactor Experiment

The U.S. Department of Energy (DOE) today released the final environmental assessment and proposed finding of no significant impact (FONSI) for the design, construction, and operation of the Molten Chloride Reactor Experiment (MCRE) at Idaho National Laboratory (INL). DOE invites the public to review the final environmental assessment and comment on the proposed FONSI for this project.

MCRE is an experiment scheduled to run for approximately six months at INL, after which it will be decommissioned. The results will provide data crucial to the development of TerraPower’s Molten Chloride Fast Reactor (MCFR) design. 

“MCRE will be the world’s first test of a fast-spectrum, salt-fueled reactor design,” said Assistant Secretary for Nuclear Energy Dr. Kathryn Huff. “This experiment will help advance an unexplored class of reactors and the environmental assessment is an important step toward demonstrating the technology.”

The MCFR would use liquid salts as both a coolant and fuel, allowing it to operate at high temperatures to produce heat or electricity more efficiently than today’s reactors. In December 2020, DOE selected a team led by Southern Company for an Advanced Reactor Demonstration Program (ARDP) Risk Reduction award to design, build, and test MCRE at INL.

As part of the ARDP project, the team will construct the experimental system offsite and ship it to INL, where it will be fueled using materials currently in storage at the laboratory.

The final environmental assessment released today details the review and analysis of alternatives DOE considered for MCRE based on the National Environmental Policy Act. DOE’s analysis determined the construction and operation of MCRE will have no significant environmental or human health impact. As a result, DOE has released a draft FONSI. DOE invites public comment the FONSI now through August 31, 2023, by mail or email at the following addresses:

Mail:     Willettia Amos

U.S. Department of Energy

Idaho Operations Office

1955 Fremont Avenue 

Idaho Falls, Idaho 83415-1235


For more information on MCRE and the Office of Nuclear Energy’s program visit

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