Final safety evaluation completed for Wyoming advanced reactor

The evaluation records the technical review by US Nuclear Regulatory Commission (NRC) staff of the construction permit application submitted by TerraPower for a Natrium reactor plant proposed to be built at the site in Lincoln County. The reactor is intended to demonstrate the Natrium sodium-cooled fast reactor technology, including a molten salt energy storage system that enables the plant to vary its supply of energy to the grid.

The NRC staff began its formal review of TerraPower's application in May 2024. It had originally set a target date of August 2026 to complete the review, but earlier this year announced plans to accelerate the process, aiming to complete it by the end of this year.

This is the first use of a fully risk-informed, performance-based (RIPB) approach to establish the licensing basis for a commercial power reactor, according to information from the NRC. The NRC’s Advisory Committee on Reactor Safeguards independently reviewed those aspects of the application that concern safety, providing the results of the review to the Commission in mid-November. The evaluation concludes there are no safety aspects that would preclude issuing the construction permit.

“We’ve finished our technical work on the Kemmerer review a month ahead of our already accelerated schedule, as we aim to make licensing decisions for new, advanced reactors in no more than 18 months,” said Jeremy Groom, acting director of the NRC’s Office of Nuclear Reactor Regulation.

The NRC completed the Environmental Impact Statement, which evaluates the environmental impacts of the proposed plant, in October. The licensing process is now in its final phase when the Commission will determine whether the staff's review supports the findings necessary to issue the permit, after which the commissioners will vote on whether to direct the staff to issue the permit.

"Today is a momentous occasion for TerraPower, our project partners and the Natrium design," TerraPower President and CEO Chris Levesque said, adding that the NRC's safety evaluation "reflects years of rigorous evaluation, thoughtful collaboration with the NRC, and an unwavering commitment to both safety and innovation".

If approved, the licence would only cover construction of the plant: TerraPower subsidiary US SFR Owner, LLC would need to submit a separate operating licence application before it would be authorised to operate the facility. Construction of the non-nuclear portions of the site are already under way.

The first Natrium project is being developed through the US Department of Energy’s Advanced Reactor Demonstration Program. The Natrium reactor is a TerraPower and GE Vernova Hitachi Nuclear Energy technology.