TerraPower Receives First Non-Light-Water Reactor Permit in More Than 40 Years
The Kemmerer project will be built on a greenfield site near a retiring coal plant in southwest Wyoming
KEMMERER, Wyo. — The Nuclear Regulatory Commission on March 4 approved a construction permit for TerraPower's Natrium reactor near Kemmerer, making it the first commercial nuclear construction approval in nearly a decade and the first for a non-light-water reactor design in more than 40 years. The agency completed its safety review in December 2025, ahead of schedule and 11% under budget.
The Kemmerer project is notable as a greenfield nuclear site, meaning the reactor will be built on land that has never hosted a nuclear facility. While the site sits near a retiring coal-fired power plant, no nuclear infrastructure exists there. By contrast, the last reactors the NRC approved for construction — Vogtle Units 3 and 4 in Georgia — were built adjacent to two existing nuclear units on an already-licensed site. That distinction, known as brownfield development, typically streamlines the permitting process because environmental and safety reviews for the location have already been conducted.
TerraPower broke ground on non-nuclear site preparation in June 2024 and can now begin building the reactor itself. The company used the NRC's traditional two-step licensing process, which requires a separate operating license application before the facility can generate power. The last commercial construction permits the NRC issued, for the Vogtle expansion in 2012, used a newer combined license process that merges both steps into a single approval.
Once operational, Natrium will become the first commercial nuclear reactor in Wyoming and is expected to bring jobs, economic benefits and a reliable energy source to the state. The project is expected to be completed in 2030.
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