WASHINGTON (December 2, 2025)—Yesterday, the Nuclear Regulatory Commission (NRC) announced that its technical staff had completed an expedited safety review of an application to construct a $10 billion, 345-megawatt experimental sodium-cooled fast nuclear reactor in Kemmerer, Wyoming. The Natrium reactor was designed by TerraPower, a company co-founded by billionaire Bill Gates, and is the recipient of a 50-50 cost-share grant (up to $2 billion) from the U.S. Department of Energy’s Advanced Reactor Demonstration Program.
Review of the construction permit application, which was submitted in March 2024, was originally scheduled to be completed in August 2026. However, as the result of political pressure from both Congress and the White House, NRC staff curtailed their review and issued a safety evaluation nine months early, conforming to the 18-month review timeline mandated by President Donald Trump’s Executive Order 14300. If NRC commissioners approve the permit, as expected, then TerraPower will be able to begin construction of the reactor shortly thereafter.
Below is a statement by Dr. Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists.
“The NRC’s rush to complete the Kemmerer plant’s safety evaluation to meet the recklessly abbreviated schedule dictated by President Trump represents a complete abandonment of its obligation to protect public health, safety and the environment from catastrophic nuclear power plant accidents or terrorist attacks. The only way the staff could finish its review on such a short timeline is by sweeping serious unresolved safety issues under the rug or deferring consideration of them until TerraPower applies for an operating license, at which point it may be too late to correct any problems. Make no mistake, this type of reactor has major safety flaws compared to conventional nuclear reactors that comprise the operating fleet. Its liquid sodium coolant can catch fire, and the reactor has inherent instabilities that could lead to a rapid and uncontrolled increase in power, causing damage to the reactor’s hot and highly radioactive nuclear fuel.
“Of particular concern, NRC staff has assented to a design that lacks a physical containment structure to reduce the release of radioactive materials into the environment if a core melt occurs. TerraPower argues that the reactor has a so-called ‘functional’ containment that eliminates the need for a real containment structure. But the NRC staff plainly states that it ‘did not come to a final determination of the adequacy and acceptability of functional containment performance due to the preliminary nature of the design and analysis.’ Even if the NRC determines later that the functional containment is inadequate, it would be utterly impractical to retrofit the design and build a physical containment after construction has begun. The potential for rapid power excursions and the lack of a real containment make the Kemmerer plant a true ‘Cowboy Chernobyl.’”