The NRC unanimously voted to issue a construction permit to TerraPower's subsidiary US SFR Owner on March 4, 2026 — the first commercial non-light-water reactor construction permit in more than 40 years and the first commercial reactor construction permit in nearly a decade. TerraPower submitted its Part 50 application in March 2024 (docketed May 2024). The NRC completed its safety review in December 2025, eight months ahead of its initial August 2026 target and 11% under budget. TerraPower began nuclear-related construction on April 24, 2026. TerraPower CEO Chris Levesque: "This is a historic day for the United States' nuclear industry." The Natrium is a 345 MWe sodium-cooled fast reactor with a molten salt energy storage system enabling flexible output of up to 500 MWe. Site: Kemmerer Power Station, Kemmerer, Wyoming, adjacent to the retiring Naughton coal plant. Non-nuclear site construction began in June 2024 at the site of PacifiCorp's retiring Naughton coal plant, Wyoming granted all required construction and operating permits in January 2025, and Kiewit Nuclear Solutions is also named as a project participant. The project is co-funded by the DOE Advanced Reactor Demonstration Program with up to $2 billion in federal cost-share, matched by TerraPower, and the reactor design builds on GE Hitachi's PRISM reactor. TerraPower targets power dispatch by the end of 2030 and describes the plant as America's first utility-scale advanced nuclear power plant. DOE's May 2026 one-year nuclear renaissance report highlighted the project's progress.