The US Nuclear Regulatory Commission has granted TerraPower permission to begin building its innovative sodium-cooled nuclear reactor in Kemmerer, Wyoming. Backed by Bill Gates, the Natrium project marks the first such approval in nearly a decade and aims to integrate energy storage for better compatibility with renewables. Construction is expected to wrap up by 2030, though an operating license remains pending.
On March 4, 2026, the US Nuclear Regulatory Commission (NRC) issued its first construction permit for a nuclear reactor in almost a decade, allowing TerraPower to start work on a site in Kemmerer, Wyoming. The company, founded and financially supported by Bill Gates, is developing the Natrium reactor in partnership with GE Hitachi Nuclear Energy as part of the Department of Energy's Advanced Reactor Demonstration Program.
The Natrium design features liquid sodium cooling, which keeps the coolant liquid without the high-pressure challenges of traditional water-cooled reactors. However, sodium's reactivity with air or water poses potential risks. As a fast-neutron reactor, it can process certain isotopes that might otherwise become radioactive waste. The plant's capacity is 345 megawatts, smaller than typical one-gigawatt facilities, and includes salt-based thermal storage to hold heat for later electricity generation. This setup enables temporary output up to 500 megawatts and supports operation alongside variable renewable energy sources.
TerraPower selected the Kemmerer site in 2021 and submitted its application in early 2024, just before the ADVANCE Act passed in June 2024 to streamline nuclear approvals. The NRC completed its review nearly 10 months ahead of schedule. Globally, only about 25 significant sodium-cooled reactors have been built, with the US last constructing one in the 1960s and operating one in the 1990s.
The project, a public-private partnership, is projected to cost at least $4 billion and finish by 2030, though delays are anticipated for this first-of-its-kind build. It arrives too late for the near-term surge in data center power needs driven by AI. An operating license is still required, and while the current administration favors simplifying such processes, the timeline may extend into the next one.
Advocates highlight nuclear power's role in providing low-carbon energy without the emissions of coal or gas plants, especially amid rising demands from technology infrastructure. Critics, however, emphasize safety concerns and challenges in managing nuclear waste, questioning the net environmental benefits.
