KEMMERER, Wyo., April 23, 2026 —TerraPower officially commenced construction on its flagship Natrium plant, Kemmerer Unit 1, in Kemmerer, Wyoming on April 23, 2026 — a milestone that makes it the first utility-scale advanced nuclear power plant to begin construction in the United States.
The groundbreaking follows the U.S. Nuclear Regulatory Commission’s issuance of a construction permit for the project, and caps years of engineering, site preparation and regulatory review.
Non-nuclear site work has been underway since TerraPower broke ground on the greenfield site in June 2024.
“This is the moment our industry has been working toward for a generation,” said Chris Levesque, President and CEO of TerraPower.
“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.”
A Next-Generation Design
The Kemmerer plant features a 345-megawatt sodium-cooled fast reactor paired with an integrated molten salt-based energy storage system — a combination unique among advanced reactor designs.
The storage system allows output to be boosted to 500 MW when demand peaks, equivalent to powering around 400,000 homes, while keeping the base reactor output steady.
The technology was developed by TerraPower and GE Vernova Hitachi Nuclear Energy.
The project is being delivered by Bechtel as the engineering, procurement and construction contractor.
“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,” said Dena Volovar, President of Bechtel’s Nuclear, Security and Environmental business.
Jobs and Community Impact
TerraPower is mobilising approximately 1,600 workers for peak construction, with around 250 permanent full-time positions once the plant is operational.
The project is sited near a retiring coal-fired power plant in Lincoln County — part of a broader coal-to-nuclear transition the company describes as the only such project currently under development in the world.
Wyoming Governor Mark Gordon welcomed the milestone: “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.”
Federal Backing and Commercial Ambitions
Kemmerer Unit 1 is being developed through the U.S. Department of Energy’s Advanced Reactor Demonstration Program, a public-private partnership.
“Today’s construction milestone is a testament to the Department of Energy’s investment in American innovation,” said Dr. Rian Bahran, Deputy Assistant Secretary for DOE’s Office of Nuclear Energy.
“When government and private industry work together, we can build a bright future for our country powered by nuclear.”
Beyond Kemmerer, TerraPower is already moving to commercialise the technology at scale, including an agreement with Meta for up to eight Natrium plants by 2035.
Construction at Kemmerer is expected to span five years, with the plant targeting operational status around 2030–2031.
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