TerraPower begins construction on Natrium power plant in Kemmerer
Construction has officially begun on TerraPower’s first Natrium power plant, in Kemmerer, Wyo. The company expects this demonstration facility—featuring a 345-MWe sodium-cooled fast reactor with an integrated molten salt–based heat storage system, which can temporarily boost power output to 500 MWe—to become the first “utility-scale advanced nuclear power plant” in the United States.
The Nuclear Regulatory Commission approved the construction permit for Kemmerer-1 in early March, marking the NRC’s first approval for any commercial nuclear reactor in nearly a decade, and the first approval for a commercial non–light water reactor in more than 40 years.
Commercial blueprint: “This is the moment our industry has been working toward for a generation,” TerraPower CEO Chris Levesque said about the start of construction. “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. The Natrium plant will deliver reliable and dispatchable power to the grid, and Kemmerer Unit 1 [will] serve as a commercial blueprint to mobilize a fleet of Natrium plants across the country and around the world.”
The development of Kemmerer-1—which dates to 2021 when the site, near a retiring coal-fired facility, was selected—is being supported by the Department of Energy’s Advanced Reactor Demonstration Program (ARDP). TerraPower broke ground on a greenfield site that is part of the nonnuclear support facilities for the project in June 2024.
Bechtel has teamed with TerraPower as the engineering, procurement, and construction partner for the Natrium project. Of this “important step forward,” Bechtel’s president of nuclear, security, and environmental business Dena Volovar said, “We’re proud to partner with TerraPower on this first-of-a-kind project, and to help establish a blueprint for how advanced reactors can be delivered to support a cleaner, more reliable energy future.”
Prospects for Wyoming: According to TerraPower, the power plant’s construction will involve approximately 1,600 workers. Construction is expected to be completed by 2030. Once operational, the facility employ about 250 full-time staff. The facility will be Wyoming’s first-ever commercial nuclear power plant.
Wyoming Gov. Mark Gordon said, “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. I want to thank everyone at TerraPower for their work getting to this day. 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.”
PacifiCorp, an early backer of Natrium, has yet to announce a power purchase agreement for the project. TerraPower’s announcement of the construction start included a quote not from PacifiCorp, but from one of its subsidiaries: Rocky Mountain Power.
Rocky Mountain Power President Dick Garlish said his company “supports a balanced, all-of-the‑above energy strategy. Baseload power is critical to serve our customers, and advanced nuclear technologies like the Natrium project [are] a promising resource.”
Commercialization plans: TerraPower has ambitious plans to commercialize its Natrium technology well beyond the Kemmerer project. In January, the company signed an agreement with Meta to provide as many as eight Natrium units by 2035. The initial two units under that agreement are to be delivered as early as 2032.
In February, the United Kingdom’s Generic Design Assessment regulatory authorities also accepted the Natrium reactor for consideration.
