The U.S. Nuclear Regulatory Commission (NRC) issued on September 29, 2026 the first construction permit for a BWRX-300 small modular reactor on American soil. The recipient is the Tennessee Valley Authority (TVA), which becomes the first U.S. utility authorized to build this design developed by GE Vernova Hitachi Nuclear Energy. The chosen site is Clinch River, near Oak Ridge, Tennessee, in close proximity to the Department of Energy’s Oak Ridge National Laboratory.
The NRC completed its review of the application in just 14 months — four months ahead of its own schedule. A result that agency chair Ho Nieh described as proof that “the new NRC knows how to make rigorous and credible safety decisions, allowing major American nuclear projects to move forward.” TVA had submitted the permit application in April 2025, building the case on the Early Site Permit already obtained in 2019 for the Clinch River site, which authorizes up to 800 MWe of water-cooled modular reactors. The current project covers a single 300 MWe unit.
This permit is the second issued in the United States for an advanced commercial reactor in 2026, following the one granted to TerraPower‘s Natrium project in Kemmerer, Wyoming, last March. At the North American level, the BWRX-300 had already secured a similar authorization in Canada: the Canadian Nuclear Safety Commission approved construction of a unit of the same design for Ontario Power Generation‘s project at Darlington in 2025. The fact that two separate jurisdictions have validated the same design in quick succession sends a clear signal to the international SMR market.
TVA stated that the permit “establishes a clear and replicable licensing pathway for future BWRX-300 applicants, improving predictability and lowering barriers for subsequent developments.” Jason Cooper, CEO of GE Vernova Hitachi Nuclear Energy, stressed that “fleet deployment is essential to scaling nuclear energy in the United States” and that Clinch River brings that model meaningfully closer to reality. A construction start date has yet to be announced: TVA is continuing engineering work and negotiations with industrial partners to finalize cost-sharing arrangements.
The financial picture remains unresolved. TVA has made clear its intention to avoid placing the full burden of a first-of-a-kind commercial technology on its Valley ratepayers alone, given that the project’s value extends well beyond the regional level. The U.S. Department of Energy has committed $400 million in cost-sharing support for the project. If TVA succeeds in closing agreements with partners and locking in a construction timeline, Clinch River could become the definitive proving ground for serial SMR construction in the United States — a manufacturing model the nuclear industry has been pursuing for years.
