The Nuclear Regulatory Commission of the United States has issued a construction permit for the first BWRX-300 small modular reactor on American soil. The document was delivered on September 29, 2026, to the Tennessee Valley Authority (TVA), the federal utility planning to deploy the reactor at the Clinch River site near Oak Ridge, Tennessee. This marks only the second construction permit ever granted for an advanced reactor in the United States — the first was issued in March 2026, when Wyoming received authorization for TerraPower’s Natrium reactor.
The BWRX-300 is a 300-megawatt boiling water reactor developed by GE Vernova Hitachi Nuclear Energy. It draws from a well-established lineage of boiling water reactor designs, but requires significantly fewer materials than previous models and incorporates passive safety systems. Components are designed to be factory-fabricated and assembled on-site, reducing construction time and complexity. The Clinch River site has the physical capacity to host up to four modular reactors, and its proximity to Oak Ridge National Laboratory — one of the country’s leading nuclear research centers — makes it a strategic landmark for SMR development in the US.
TVA submitted its permit application to the NRC in May 2025, becoming the first American utility to formally apply for the BWRX-300 design. The regulatory review was completed in just over a year — a relatively short timeline by US standards. In December 2025, the Department of Energy had already awarded TVA a $400 million grant to support the project’s financing. An official construction start date has not yet been announced, as TVA is still negotiating cost-sharing arrangements with its industrial partners. When the application was filed, the utility indicated a target commercial operation date of around 2032.
Eric Gray, CEO of GE Vernova’s Power segment, described the permit as “an important moment for new nuclear in the United States.” Beyond the statements, the milestone carries real weight on the industrial front: the BWRX-300 is already under development in Canada, where Ontario Power Generation has selected it for the Darlington site, and it is among the options being evaluated in Poland and Sweden. A US construction permit significantly strengthens the project’s regulatory and commercial credibility on a global scale. Surging electricity demand — driven by data centers, artificial intelligence, and industrial electrification — is creating urgent pressure to add zero-emission baseload capacity, and SMRs are today among the few technologies capable of meeting that demand reliably.
If the Clinch River project stays on schedule, the American BWRX-300 could enter service before the end of the next decade. It will be the most visible proving ground for demonstrating that modular reactors can be built on time and within budget — the real challenge the industry must overcome to turn permits into actual megawatts.
