The NRC permit was issued earlier than the September 2026 timeline previously cited in ENR reporting, following completion of the agency’s safety evaluation and environmental review.

“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 TerraPower President and CEO Chris Levesque, describing the Kemmerer Unit 1 project as a commercial blueprint to mobilize a fleet of Natrium plants across the country and around the world.

Wyoming Gov. Mark Gordon (R) welcomed the milestone as a sign of the state’s continued energy leadership. “Wyoming has long powered this country, and today we are leading again, this time in next-generation nuclear technology,” he said, citing the project’s promise of reliable power and good-paying jobs.

Plant Design and Technology

The Kemmerer Unit 1 plant is designed around a sodium-cooled fast reactor paired with a molten salt energy storage system, a joint technology of TerraPower and GE Vernova Hitachi Nuclear Energy.

The system provides steady baseload generation at 345 MW and can boost output to 500 MW during peak demand—enough to power roughly 400,000 homes—enabling the plant to complement intermittent renewable resources on the grid.

The plant is being developed under the U.S. Dept. of Energy’s Advanced Reactor Demonstration Program, a public-private initiative supported by roughly $2 billion in federal funding matched by TerraPower.

“The Natrium reactor shows that when government and private industry work together, we can build a bright future for our country powered by nuclear,” said Rian Bahran, DOE’s deputy assistant secretary for nuclear energy.

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Construction Scope and Workforce

Bechtel is serving as the engineering, procurement and construction contractor for the project, a role it has held since 2020.

“The start of construction at Kemmerer Unit 1 marks an important step forward for the project and for the next generation of U.S. nuclear energy,” said Dena Volovar, president of Bechtel’s Nuclear, Security and Environmental business.

“By combining TerraPower’s reactor innovation with Bechtel’s processes, experience and execution model, we will deliver these nuclear projects consistently, safely and at scale,” she added.

Early work has included site preparation and construction of non-nuclear support facilities and infrastructure, with reactor construction now proceeding under federal authorization.

NRC spokesman Scott Brunell previously told ENR the project would be reviewed as a full commercial power plant, not a non-power demonstration facility, because it will produce electricity when completed.

With construction underway, TerraPower is mobilizing a workforce of about 1,600 craft workers at peak, with approximately 250 permanent employees expected once the plant becomes operational. The project is located at the site of PacifiCorp’s retiring Naughton coal-fired power plant and will supply electricity to the grid through Rocky Mountain Power, the project’s utility partner.

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Commercialization Push

TerraPower has advanced commercialization efforts for the Natrium design ahead of the Kemmerer plant’s projected completion by the end of the decade.

The company has an agreement with Meta for up to eight Natrium plants by 2035 and, in March 2025, announced a strategic alliance with professional services firm KBR to establish a replicable contracting framework for deployment in North America, the U.K. and the European Union.

TerraPower was the first U.S. developer to seek a construction and operating permit for a commercial-scale advanced reactor, filing its application with the commission in March 2024.

The start of nuclear construction at Kemmerer represents a key test of whether advanced reactor designs can move beyond pilot-scale development into repeatable commercial delivery—a threshold the U.S. nuclear sector has not crossed in decades—and signals a potential pathway for converting retiring coal assets into firm, dispatchable power generation.