RELEASE: The NRC Issues Construction Permit for Terrapower’s Natrium Reactor

WASHINGTON, DC, March 4, 2026 — The U.S. Nuclear Regulatory Commission (NRC) has voted to issue a construction permit to TerraPower’s subsidiary, US SFR Owner, for its Natrium advanced reactor project in Kemmerer, Wyoming. The permit authorizes TerraPower to begin nuclear-related construction activities for the sodium-cooled fast reactor and a molten salt-based energy storage facility at the Kemmerer site.

The construction permit represents a major regulatory milestone for the Natrium project and the first approval for a commercial Generation IV advanced reactor under the NRC’s existing 10 CFR Part 50 licensing framework. According to the NRC, this is the first commercial reactor construction approval in nearly a decade and the first approval for a non-light-water reactor in more than 40 years. This is also the first application to use a fully risk-informed, performance-based licensing basis for a power reactor. The Commission’s decision follows the NRC staff’s detailed safety and environmental reviews pursuant to the Atomic Energy Act and the National Environmental Policy Act.

The Kemmerer construction permit application was accepted for docketing on May 14, 2024. In its initial review schedule, the NRC projected completing the final safety evaluation in August 2026, reflecting an estimated 27‑month review timeline. The agency ultimately issued its final safety analysis on December 1, 2025, approximately eight months ahead of the originally projected schedule. The Commission review, hearing, and vote process took another three months.

“Today’s vote marks an important step forward for advanced reactor deployment in the United States,” said Adam Stein, Director of Nuclear Energy Innovation at the Breakthrough Institute. “Completing a complex advanced reactor licensing review significantly ahead of schedule reflects improvements in the efficiency of the NRC’s review process while maintaining the agency’s rigorous safety and environmental standards. Predictable, risk-informed licensing processes are essential if the United States is to expand nuclear energy capacity at the pace required to meet national goals.”

The permit also validates TerraPower's separation of the nuclear and energy islands, which significantly reduced the regulatory burden on the project, by exempting the energy storage and energy generation parts of the plant from NRC licensing. Issuance of a construction permit does not authorize operation of the reactor. TerraPower must still complete construction, submit an operating license application, and satisfy all applicable safety and regulatory requirements before loading fuel and beginning operations.

The Commission’s decision also reflects ongoing efforts to modernize nuclear licensing processes, including reforms enacted through the ADVANCE Act and related policy initiatives intended to enhance regulatory clarity and efficiency while preserving safety and security standards. Early licensing milestones such as the Kemmerer construction permit illustrate how improved regulatory efficiency can support the timely deployment of next‑generation nuclear energy systems.

“The significant improvement in efficiency, without major changes to the regulations, proves that the update to the NRC’s mission, mandated by the ADVANCE Act, was both necessary and effective.”

The Breakthrough Institute will continue to monitor the project’s licensing progression and broader implementation of advanced reactor regulatory reforms.

###

Media Contact:

Adam Stein

Director of Nuclear Energy Innovation

adam@thebreakthrough.org