A nuclear first: TerraPower officially starts construction on next-gen Natrium plant in Wyoming

TerraPower announced Thursday that it has started construction on its Natrium plant, making it the first company in the U.S. to break ground on an advanced nuclear power facility.

“This is the moment our industry has been working toward for a generation. We’re not just breaking new ground on a first-of-a-kind nuclear plant in Wyoming; we’re building the next generation of America’s energy infrastructure,” said Chris Levesque, CEO of TerraPower, in a statement.

The Bellevue, Wash.-based company began building its demonstration plant in Kemmerer, Wyo., in 2024, starting with construction of non-nuclear features. Last month, TerraPower received unanimous approval from the Nuclear Regulatory Commission (NRC) to proceed with the nuclear components.

The facility includes a 345-megawatt, sodium-cooled fast reactor paired with a system that holds excess heat inside of molten salt. Tapping the thermal salt battery can boost the plant’s power output to 500 megawatts for more than five hours. By comparison, Seattle uses around 2,000 megawatts during extreme weather events.

TerraPower aims to have the reactor splitting atoms by the end of 2030. Roughly 1,600 workers will be hired during construction, with approximately 250 full-time staff employed once the facility is operational.

The Wyoming plant was estimated in 2021 to cost about $4 billion; no updated figures have been provided. Levesque previously told GeekWire that private investments from Bill Gates and others as well as $2 billion federal grant mean “we’re building that project without burdening the ratepayers.”

The milestone comes as America’s nuclear sector has surged back to life after decades of stagnation, driven by tech giants scrambling to power data centers nationwide and rising energy demands across commercial, residential and industrial sectors.

Founded 20 years ago, TerraPower plans to build hundreds of its reactors, which are smaller and less costly than conventional facilities. Using prefabricated components, the company believes it can compress construction timelines to just three years — a fraction of the time required for traditional plants. The most recently completed conventional nuclear facility in the U.S. — the Plant Vogtle site in Georgia — took more than a decade to build.

TerraPower is already signing customers. In January, the company reached a deal with Meta to build up to eight Natrium reactors in the U.S. with the first two targeted to come online by 2032. If the full order is fulfilled, the additional reactors will be operating by 2035. The company also has memorandums of understanding with government agencies in Utah and Kansas to explore potential sites in those states.

“The start of construction on TerraPower’s Natrium plant in Kemmerer marks a major milestone not just for Wyoming, but for the future of American energy,” said Wyoming Gov. Mark Gordon. “I want to thank everyone at TerraPower for their work getting to this day.”