The US Nuclear Regulatory Commission (NRC) has approved a construction permit for the Tennessee Valley Authority (TVA) to build the country’s first commercial small modular reactor (SMR) at the Clinch River site in Tennessee. The project will use GE Vernova Hitachi’s 300MW BWRX-300 boiling-water reactor, marking a major step toward commercial SMR deployment in the United States.
The NRC completed its review in 14 months, four months ahead of its scheduled timeline. The approval is the NRC’s second major new-reactor construction permit of 2026, following TerraPower’s Natrium reactor in Wyoming. TVA had already received an early site permit for Clinch River in 2019, helping to accelerate the latest review.
The BWRX-300 uses a natural-circulation design and passive safety systems, and the same technology is already under construction at Ontario Power Generation’s Darlington site in Canada. TVA has not yet announced a construction start date, although the project has been targeting commercial operation in December 2033. The project has also received $400 million in US Department of Energy support.
The permit does not allow TVA to load fuel or operate the reactor. After construction, TVA will need a separate NRC operating licence before electricity generation can begin. Nevertheless, the decision provides an important US regulatory milestone for the BWRX-300 and could help establish a pathway for future fleets of SMRs as electricity demand rises from data centres, industrial activity and electrification.