TerraPower, backed by Bill Gates, wins approval to build next-generation nuclear reactor

The Nuclear Regulatory Commission this week cleared TerraPower to proceed with construction of a new nuclear reactor adjacent to an ageing coal-fired power plant in Wyoming.

The permit granted to TerraPower is the first the NRC has issued in nearly 10 years. The startup, founded by Bill Gates in 2015 and backed by Nvidia, has been developing its Natrium reactor with GE Vernova Hitachi. The completed plant is expected to produce 345 megawatts of power, making it about two-thirds smaller than today’s full-size nuclear reactors, while still several times larger than many small modular reactor concepts pursued by other startups.

Natrium stands apart from other reactors not only for its scale but also for its design. Specifics. While most nuclear reactors built over the last half-century have relied on water for cooling, Natrium uses molten sodium, which TerraPower says offers improved safety. It is the first commercial reactor approved by the NRC in more than 40 years that does not use ordinary water as its coolant.

The reactor is designed to operate with excess molten sodium, which will be stored in large, insulated tanks. That setup allows the atom-splitting process to continue even when electricity demand is low, while the heated sodium stores that energy for later use. The stored heat can then help cover dips in wind and solar generation. Because nuclear plants operate most efficiently near full capacity, storing surplus energy as heat could help reduce overall generation costs.

The NRC’s decision is significant in part because TerraPower used the long-standing licensing pathway, which gives it authority to build on private land. The Department of Energy recently eased some of its safety requirements, but the updated rules apply only to land owned by the department.

TerraPower is one of several nuclear startups that have received support from technology companies or their founders. As data centres push electricity demand higher, the Trump administration has faced increasing pressure to expand generating capacity, including by constructing new nuclear reactors.

Investors have also taken notice of both trends, and nuclear startups have attracted well over $1 billion in funding in recent months. TerraPower by itself has raised $1.7 billion in total, including a $650 million round that closed in June, according to PitchBook.

Even with the growing momentum, nuclear energy continues to face major challenges. So far, it remains one of the costliest sources of new power generation. That is partly due to overruns on large nuclear projects, but it also reflects how much solar, wind, and battery technologies have reduced costs over time.

Nuclear startups are betting that mass manufacturing will help reduce capital costs, though this has not yet been proven in practice. And while manufacturing at scale can eventually reduce expenses, it often takes a decade or more for those savings to materialise fully.