A major milestone for advanced nuclear energy in the United States has been reached after the Nuclear Regulatory Commission (NRC) voted to approve construction of key nuclear components for TerraPower’s next-generation power plant in Kemmerer, Wyoming. The project, backed by Microsoft co-founder Bill Gates, is expected to showcase new reactor technology designed to improve both safety and efficiency in nuclear power generation.
The NRC, an independent federal agency responsible for nuclear safety regulation, voted Wednesday to grant TerraPower a permit to construct the nuclear portions of its Natrium power plant. According to the agency, the official permit will be issued soon. NRC Chairman Ho Nieh described the decision as a significant step forward for the country’s nuclear energy ambitions, emphasizing that the approval reflects the commission’s commitment to timely decisions grounded in rigorous and independent safety evaluations.
TerraPower first broke ground at the Kemmerer site in 2024, but it had been awaiting regulatory approval to begin work on the nuclear elements of the facility. The company formally applied for the construction permit in March 2024. The review process included several regulatory steps, including the release of an environmental impact statement in October 2025 and a safety evaluation completed in December of the same year.
The Natrium reactor represents a new generation of nuclear technology designed to address some of the long-standing challenges associated with traditional nuclear plants. Unlike conventional reactors that rely on high-pressure water cooling, the Natrium system uses liquid sodium as a coolant. Because liquid sodium has a significantly higher boiling point than water, the system operates at lower pressure and is designed to reduce the risk of overheating. Engineers believe this approach could improve safety while also increasing operational efficiency.
Another defining feature of the Natrium design is its integrated molten salt energy storage system. This technology functions similarly to a large-scale battery, allowing the plant to store heat and release it later to increase power output when needed. While the plant is designed to produce 345 megawatts of electricity under normal conditions, the storage system can boost its capacity to 500 megawatts for up to five hours during periods of high demand.
According to the NRC, TerraPower’s reactor is notable for being the first commercial nuclear reactor approved for construction in nearly a decade. It also marks the first approval of a non–light water reactor design for commercial use in more than 40 years. While another company, Kairos Power, received permits in November 2024 to build components for its next-generation Hermes 2 reactor, those approvals were for a smaller demonstration-scale facility rather than a full commercial plant.
Regulators noted that their technical review of the Natrium reactor design was completed in less than 18 months. However, the approval has not been without criticism. Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists and a longtime critic of nuclear expansion, raised concerns about the safety of the reactor’s design and suggested that regulators may have rushed their review. At the same time, the NRC has frequently faced criticism from other stakeholders for what they describe as an overly bureaucratic approval process that can slow the development of new energy technologies.
The push to accelerate nuclear permitting has gained political attention in recent years. The Trump administration has advocated for faster approvals to help expand domestic nuclear power capacity, though efforts to streamline the regulatory process began prior to Trump’s most recent term in office. Industry groups, including the American Nuclear Society, have highlighted that TerraPower’s application was the first to use a “risk-informed, performance-based” licensing process. This regulatory approach is designed to focus on real safety risks while reducing unnecessary regulatory burdens.
TerraPower President and CEO Chris Levesque said the company had worked closely with NRC staff for several years leading up to the permit approval. According to Levesque, TerraPower spent four years engaging with regulators, sharing technical information and discussing the Natrium design before submitting its formal application.
Levesque welcomed the commission’s vote as a landmark moment for the company and the broader nuclear industry. He said TerraPower plans to move quickly to begin construction on the Natrium plant in the coming weeks.
“We are beyond proud to receive a positive vote from the Nuclear Regulatory Commissioners to grant us our construction permit for Kemmerer Unit One,” Levesque said. “This is the first commercial-scale, advanced nuclear plant to receive this permit.”
If completed successfully, the Natrium facility could serve as a model for a new generation of nuclear reactors designed to provide reliable, carbon-free electricity while addressing concerns about safety, flexibility, and grid stability. The project is being closely watched by policymakers, energy companies, and environmental advocates as the United States seeks new ways to meet growing energy demand while reducing greenhouse gas emissions.