TerraPower Breaks Ground on Wyoming’s First Nuclear Reactor Near Kemmerer
Why It Matters
Wyoming is poised to become a landmark in American energy history. The groundbreaking of TerraPower’s Natrium nuclear power plant near Kemmerer marks the first time the state — long synonymous with coal, oil, and natural gas — will host a commercial nuclear reactor, and represents a potential turning point for domestic energy production across the Mountain West.
For Kemmerer and the surrounding region, the project promises hundreds of construction jobs, long-term employment, and a source of electricity that developers say will be competitive with the cheapest power generation available today.
What Happened
On Wednesday, April 22, 2026, construction crews officially broke ground on the nuclear components of TerraPower’s Natrium power plant just south of Kemmerer, Wyoming. The site sits near the existing Naughton natural gas-fired power plant, chosen years ago for its available land, water access for cooling, and electrical transmission infrastructure.
High winds gusting past 30 miles per hour slowed some activity on the day — cranes and smaller lifts were lowered as a precaution to prevent siding panels from acting as sails. Even TerraPower President and CEO Chris Levesque missed the groundbreaking ceremony in person when his plane was unable to land in Salt Lake City due to the weather.
“It’s really historic,” Levesque told WyoFile by phone. “Wyoming is really the center of this. It will have benefits for Wyoming: cheap electricity and jobs.”
The Bill Gates-backed company, based in Bellevue, Washington, selected the Kemmerer site nearly five years ago. Construction on non-nuclear components of the facility began in 2024. The nuclear construction now underway follows two major regulatory milestones: a Wyoming Industrial Siting Council permit obtained in early 2025 and a U.S. Nuclear Regulatory Commission construction permit awarded in March 2026.
By the Numbers
- 345 megawatts — the expected power output of the Natrium plant upon completion
- 42 months — the projected construction timeline, targeting a 2031 completion
- ~1,300 construction jobs expected during the build phase
- 250 long-term positions projected once the plant is operational
- ~1,000 engineers spent more than three years designing the plant to secure federal regulatory approval
- 60 acres — the total footprint of the Natrium facility site
Next-Generation Technology
The Natrium plant takes its name from the Latin word for sodium, which serves as the reactor’s cooling agent. Unlike conventional nuclear plants that rely on water-based cooling — which generates high pressure and requires extensive steel and concrete containment — the sodium-cooled design reduces material requirements and construction complexity.
The reactor will also be built underground, further distinguishing it from the 94 existing nuclear reactors currently operating across the United States.
“We say it’s not your grandfather’s power plant,” Levesque said. “It’s a totally different design.”
Levesque said the Natrium reactor is expected to be economically competitive with combined-cycle natural gas plants, widely considered among the most cost-efficient electricity sources available. The original project cost was billed at approximately $4 billion, though Levesque acknowledged that figure has risen due to increased construction labor and steel costs, declining to specify a new estimate.
Zoom Out
The United States has not opened a new commercial nuclear power station in over a decade. Following the partial meltdown at Three Mile Island in 1979, the nuclear industry stagnated for decades, with more plants being retired than built. Only three reactors have come online in the 21st century — Tennessee Valley Authority’s Watts Bar Unit 2 in 2016, and two reactors added to Georgia’s Plant Vogtle in 2023 and 2024.
“It’s a big deal for the industry,” Levesque said. “This is America’s next commercial nuclear power station.”
The Kemmerer project arrives as Wyoming and other Western states wrestle with long-term energy planning. Some Wyoming communities have called for more time to consider how nuclear energy fits into their futures as the federal government moves quickly to expand the industry. Meanwhile, at least one Wyoming electric utility has moved away from wind and solar in its long-term planning, signaling a regional appetite for reliable, dispatchable power sources like nuclear.
If the Natrium plant reaches completion on schedule, the project will have gone from announcement to grid contribution in approximately one decade — a remarkable timeline for an industry not known for speed.
What’s Next
Construction is expected to continue over the next 42 months, with a targeted completion date of 2031. TerraPower leadership has indicated the project will proceed despite elevated material costs, citing the long-term economic and energy independence benefits of bringing next-generation nuclear power online in Wyoming.
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