The Nuclear Regulatory Commission (NRC) has issued the Bill Gates-backed nuclear reactor company TerraPower a construction permit for its Natrium reactor in Kemmerer, Wyo.
TerraPower, based in Bellevue, Wash., said in a Wednesday press release that it is the first commercial-scale advanced nuclear power plant to ever receive this permit. This is the first commercial reactor NRC approved for construction in nearly a decade and the first approval of a non-light water reactor in over 40 years, NRC said in its press release.
The company plans to convert an old coal-powered plant in Kemmerer, Wyo. into a nuclear plant, Kemmerer Unit 1. The plant will have the Natrium design, a 345-megawatt sodium fast reactor, with a molten salt-based energy storage system. The energy storage technology can boost the system’s capacity to 500-megawatts of power when needed, according to the release.
The project is expected to be completed by 2030, the company said. TerraPower President and CEO Chris Levesque said the company will start reactor construction in the coming weeks. TerraPower already started non-nuclear construction at the Kemmerer site in July 2024 after awarding two rounds of vendors to work on the project.
The first round of Natrium vendors were selected in August 2023 and the second round in February 2024.
“Today is a historic day for the United States’ nuclear industry,” Levesque said. “We are beyond proud to receive a positive vote from the Nuclear Regulatory Commissioners to grant us our construction permit for Kemmerer Unit One. Our team has worked relentlessly for over 4 years with the NRC staff to get to this moment.”
The company filed its construction permit application for the project in March 2024, and it was accepted for review in May 2024. NRC originally planned to complete the application review by August 2026 but pivoted to an accelerated schedule of Dec. 31, 2025.
NRC completed TerraPower’s final environmental impact statement in October 2025 and its final safety evaluation in December 2025. Before operation begins, the company still needs to submit a separate operating license application, NRC said.
Pro nuclear Sens. John Barrasso (R-Wyo.) and Cynthia Lummis (R-Wyo.) issued statements applauding NRC approval for TerraPower’s reactor.
“Today is a landmark day for Wyoming,” Lummis said in her Wednesday statement. “Wyoming has long powered this nation and I’m proud that we are leading the next generation of nuclear energy. TerraPower’s advanced reactor will bring economic opportunity to Kemmerer and western Wyoming, while proving that America can build the technologies of the future right here at home.”
“Wyoming is the energy capital of America. We are also the number one producer of uranium in the country,” Barrasso said.“That’s why Wyoming is the right place to build modern nuclear energy infrastructure that provides safe, affordable, and reliable energy. This groundbreaking project is another way to help diversify Wyoming’s already strong energy economy.”
Though Wyoming does not currently have an operating nuclear reactor, it has the largest reserve of uranium ore in the United States, according to the Energy Information Administration. TerraPower’s Natrium reactor will use high-assay low-enriched uranium (HALEU) for its fuel.
Kemmerer will be developed through the Department of Energy’s Advanced Reactor Demonstration Program. Through this public-private partnership, DOE will financially support the Natrium reactor’s technology and commercial viability.