On September 29, 2026, the U.S. Nuclear Regulatory Commission issued the first construction permit in the United States for a GE Vernova Hitachi BWRX-300 small modular reactor to the Tennessee Valley Authority for installation at the Clinch River site in Oak Ridge, Tennessee. This milestone marks the first such permit for the BWRX-300 design in the U.S. and represents a significant step toward deploying a new generation of nuclear power. The Tennessee Valley Authority had submitted its construction permit application for the Clinch River project in April 2025, building on an existing Early Site Permit for the location within the Oak Ridge nuclear ecosystem near the U.S. Department of Energy's Oak Ridge National Laboratory.
This image depicts the signing of the construction permit described in the first paragraph, marking the NRC's issuance of the first US construction permit for the BWRX-300 design to the Tennessee Valley Authority.
The BWRX-300 is a 300-megawatt small modular reactor that relies on natural circulation for cooling, where water moves within the reactor core by convection without the need for electrical pumps, in contrast to most nuclear reactors that require active pumping systems. This design feature enables passive safety functions, allowing the reactor to maintain a safe state and remove decay heat even during power loss scenarios without external power or operator action, as described in technical references. The reactor design also leverages decades of boiling water reactor operating experience, evolving from earlier models like the Economic Simplified Boiling Water Reactor (ESBWR) and utilizing components of the Advanced Boiling Water Reactor (ABWR), to simplify construction and operation through a reduced-component configuration.
The NRC's decision adds to growing regulatory momentum for the BWRX-300 across North America, following Canada's issuance of a construction license to Ontario Power Generation for the Darlington New Nuclear Project in April 2025 and subsequent licensing progress, including the submission of a license to operate application in March 2026 currently under review. However, while GE Vernova Hitachi initially projected in 2019 that the first BWRX-300 unit could cost less than $1 billion to build, recent Canadian projects have shown significantly higher costs, with Ontario Power Generation's first unit forecast at CA$7.7 billion (approximately US$5.6 billion) and additional units estimated at CA$13.2 billion (approximately US$9.6 billion) for three further units, raising questions about the economic viability of small modular reactors despite their design simplifications.