TerraPower starts building first utility-scale advanced nuclear power plant in the US 

Bill Gates – backed TerraPower has started of construction on its flagship Natrium plant in Kemmerer, Wyoming, which it says is on track to be the first utility-scale advanced nuclear power plant in the United States. 

The news follows the issuance of a construction permit by the U.S. Nuclear Regulatory Commission (NRC) and is the culmination of years of innovation, engineering and disciplined site preparation, the company said. 

The plant features a 345-megawatt (MW) sodium-cooled fast reactor with an integrated molten salt-based energy storage system. The storage technology can boost energy output to 500 MW of power when needed, equivalent to the amount of energy needed to power around 400,000 homes, TerraPower said. 

The energy storage capability is designed to keep base output steady, ensuring constant reliability, and can quickly ramp up when demand peaks, the company said, adding that it is the only advanced reactor design with this unique feature. 

“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,” TerraPower CEO Chris Levesque said in an April 23 news release.  

“The Natrium plant will deliver reliable and dispatchable power to the grid and Kemmerer Unit 1 serve as a commercial blueprint to mobilize a fleet of Natrium plants across the country and around the world.” 

TerraPower is mobilizing a workforce of roughly 1,600 workers to begin plant construction, bringing the first Natrium reactor and energy storage system one step closer to fruition. 

“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 Governor Mark Gordon. “Wyoming has long powered this country, and today we are leading again, this time in next-generation nuclear technology. This project reflects our commitment to reliable energy, good-paying jobs, and a future built on innovation and Wyoming values.” 

The first Natrium plant is being developed through the U.S. Department of Energy’s Advanced Reactor Demonstration Program (ARDP), a public-private partnership. When complete, the project will be the first utility-scale advanced nuclear power plant in the U.S. and Wyoming’s first-ever commercial nuclear generating station.  

The project has been under active development since TerraPower broke ground on the greenfield site in June 2024 and began construction on non-nuclear support facilities. 

TerraPower is rapidly commercializing the Natrium technology; which includes an agreement with Meta for up to eight Natrium plants by 2035.