In a landmark moment for the American energy sector, the U.S. Nuclear Regulatory Commission (NRC) voted on March 4, 2026, to award TerraPower a construction permit for the Kemmerer Power Station Unit 1, making it the first commercial scale advanced nuclear plant to ever receive such approval and the first NRC construction permit for a non-light-water reactor in over 40 years. The NRC had completed its final safety evaluation in December 2025, a full month ahead of an already accelerated schedule and 11 percent under budget.

Steel in the Ground on Americas Energy Frontier

With regulatory clearance secured, TerraPower formally broke ground on nuclear construction at the Kemmerer site on April 23, 2026, a milestone that followed years of preparatory non-nuclear works that began in June 2024. The project had also completed the 30,000 sq ft Kemmerer Training Center by August 2025 to build a future workforce for the advanced nuclear industry. TerraPower has since signed agreements to explore additional Natrium deployments in Utah, Kansas, and with Sabey Data Centers, positioning Kemmerer Unit 1 as a commercial blueprint for a national fleet. This next-generation nuclear expansion is occurring alongside breakthroughs in nuclear medicine infrastructure, including TerraPower Isotopes’ US$450 million Bellwether Laboratory in South Philadelphia, which is designed to dramatically expand domestic production of Actinium-225 for targeted cancer therapies.

Project Overview

• Project Name: Kemmerer Power Station Unit 1 (Natrium Demonstration Plant)
• Location: Kemmerer, Wyoming, USA
• Developer/Owner: TerraPower (subsidiary: US SFR Owner LLC), co-founded by Bill Gates
• Total Cost/Value: Approximately USD 4 billion
• Scale/Capacity: 345 MW baseload capacity, scalable to 500 MW with molten salt energy storage
• Construction Start: June 2024 (non-nuclear works); April 23, 2026 (nuclear construction)
• Expected Completion: 2030 (operational target revised to 2031 per some sources)
• Funding/Financing: TerraPower (50%) and U.S. Department of Energy Advanced Reactor Demonstration Program (50%) under a seven-year USD 2 billion matching agreement signed in 2020
• Current Status: Full nuclear construction underway following NRC construction permit issued March 2026
• Key Milestone: First commercial scale advanced nuclear reactor to receive an NRC construction permit; first non-light-water commercial reactor permit in over 40 years

Project Team

• TerraPower — Project Developer and Owner
• GE Hitachi Nuclear Energy — Co-developer of the Natrium reactor design
• U.S. Department of Energy (Advanced Reactor Demonstration Program) — Co-funder and federal partner
• U.S. Nuclear Regulatory Commission (NRC) — Licensing and regulatory authority
• Wyoming Industrial Siting Council — State permitting authority (construction permit granted January 2025)
• PacifiCorp — Early project backer and prospective offtaker (power purchase agreement not yet finalised)
• Framatome — HALEU fuel metallization pilot development (Richland, Washington)
• North Americas Building Trades Unions (NABTU) — Skilled trades labour partner
• Meta — Strategic agreement for up to eight future Natrium plants (announced January 2026)
• Utah Office of Energy Development and Flagship Companies — MOU partners for potential second Natrium plant in Utah
• Evergy and State of Kansas — MOU partners for potential Natrium deployment in Kansas
• Sabey Data Centers — Strategic collaboration partner for wide scale Natrium deployment

Reported 19th November 2021: TerraPower, a start-up co-founded by Bill Gates to modernize nuclear reactor designs, has selected Kemmerer, a small coal-mining town in Wyoming, as the ideal location for its first demonstration reactor. It intends to construct the facility in the frontier-era coal town by 2028. According to TerraPower CEO Chris Levesque, the plant’s construction will employ 2,000 employees at its height from Kemmerer. In addition, it will create new clean-energy employment in an area dominated by the coal and gas industries. Today, a local power plant, a coal mine, and a natural gas processing facility give more than 400 employment – a sizable amount for a region with a population of just about 3,000 people.

Details on the Wyoming nuclear plant

TerraPower chose a location based on geological and technical variables like seismic and soil characteristics, as well as community support, according to Levesque. Once completed, the facility will have a baseload capacity of 345 megawatts with the ability to increase to 500 megawatts. The facility will cost roughly $4 billion to complete, with TerraPower funding half of the way and the US Department of Energy’s Advanced Reactor Demonstration Program funding the other half. The Kemmerer plant will be the first to deploy Natrium, an advanced nuclear design developed by TerraPower in collaboration with GE-Hitachi.

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Instead of water, natrium plants employ liquid sodium as a cooling agent. Because sodium has a greater boiling point and can absorb more heat than water, high pressure does not accumulate inside the reactor, lowering the chance of an explosion. “China and Russia are continuing to develop new facilities using sophisticated technology similar to ours, with the goal of exporting such plants to a variety of different nations across the world.” “As a result, the US administration was worried that the US had not been pushing forward in this manner,” Levesque explained.