A rendering of the Natrium plant. (Image: Terrapower)
The U.S. Nuclear Regulatory Commission has formally accepted TerraPower’s small modular reactor construction permit application and is scheduling it for review.
The company’s Natrium reactor demonstration project—the nation’s first commercial advanced reactor of its kind—would be built on land in Wyoming near one of the state’s retiring coal plants. Kemmerer Power Station Unit 1 would operate as a 345-MW sodium-cooled reactor in conjunction with molten salt–based energy storage.
If approved, the construction permit will be the first ever issued by the NRC for a commercial non–light water power reactor. (For clarification purposes, the Atomic Energy Commission—predecessor to the NRC—issued a construction permit in 1962 for Peach Bottom-1, a high temperature gas reactor, and in 1968 for the Fort St. Vrain nuclear power plant, also an HTGR. Both of these were non-LWR reactors that operated commercially.)
Support for the project: Natrium is one of two advanced reactor demonstration projects selected for competitive funding through the Department of Energy’s Advanced Reactor Demonstration Program. (X-energy’s Xe-100 is the other.) TerraPower received $1.6 billion in funding from the Bipartisan Infrastructure Law signed by President Biden in November 2022, which is to be used to ensure the completion of the plant. The Bill Gates–backed company has also raised more than $1 billion in private funding.
Earlier this year, TerraPower announced the second round of contracts for long-lead suppliers supporting the development of the Natrium reactor.
A complex design: Natrium will use liquid sodium as a coolant instead of water. According to TerraPower, the reactor features improved fuel utilization, enhanced safety features, and a streamlined plant layout that will require fewer overall materials to construct. The power plant’s storage technology enables boosting of the system’s output to 500 MWe for more than five and a half hours when needed to meet additional grid demand.
Given the complexity of the design, TerraPower worked through preapplication materials with the NRC before submitting its formal application. Its submission applied new technology-inclusive guidance recently issued by the NRC to ensure consistency, quality, and uniformity of reviews for non–light water reactor applications. The guidance is part of the Licensing Modernization Project, an effort in collaboration with the nuclear industry and the DOE.
“During the acceptance review, the NRC staff identified several technical topics that were previously identified in the March 2024 Preapplication Readiness Assessment Report for Kemmerer Power Station Unit 1 Preliminary Construction Permit Application,” the agency wrote in its acceptance notice to TerraPower, adding, “Several topics continue to require additional clarity or information and will likely require an increased focus by [TerraPower] and the NRC staff to ensure a timely completion of the review. The NRC staff will also take these issues into consideration when developing the review schedule,”
TerraPower plans to get ahead on the project by starting nonnuclear construction at the site this summer.
