The Clinch River Nuclear Project has secured a major US regulatory approval after receiving a construction permit for its proposed 300MW small modular reactor in Tennessee. The Nuclear Regulatory Commission (NRC) issued the permit to the Tennessee Valley Authority (TVA) on September 28, 2026.
The approval clears a significant licensing hurdle for the proposed BWRX-300 nuclear generating unit. However, TVA has yet to make a final investment decision authorising full construction. The development carries an estimated investment of up to $5.4 billion, although TVA has not confirmed the final construction budget. The project will occupy TVA’s Clinch River Nuclear Site near Oak Ridge, Tennessee.
Clinch River Nuclear Project receives federal construction approval
The NRC issued Construction Permit No. CPAR-2 for Clinch River Nuclear Unit 1. The approval followed extensive safety and environmental assessments of TVA’s construction permit application.
TVA submitted its application in April 2025 and completed the required submission in May 2025. Subsequently, the regulator conducted technical assessments and environmental reviews.
The NRC completed its final Supplemental Environmental Impact Statement in April 2026. It also completed its final safety evaluation in June 2026.
Furthermore, the regulator conducted a mandatory public hearing on August 13, 2026. The review process concluded with the construction permit’s issuance in September.
According to the Federal Register notice published October 5, the permit authorises TVA to construct the proposed nuclear facility. It confirms that the regulator found TVA technically and financially qualified to undertake the authorised construction activities.
However, the permit does not automatically commit TVA to building the reactor. The utility must still secure its board’s final approval and complete commercial arrangements.
Engineering and planning activities will continue as TVA negotiates cost-sharing arrangements with industry partners. Bechtel, Sargent & Lundy and GE Vernova Hitachi Nuclear Energy support the project.
Clinch River Nuclear Project advances BWRX-300 construction preparations
The proposed facility will use GE Vernova Hitachi Nuclear Energy’s BWRX-300 boiling-water small modular reactor.
The reactor will generate approximately 300MW of electricity. Its design incorporates natural circulation and passive safety systems to simplify operations.
Additionally, the modular design allows manufacturers to fabricate major components before transporting them to the construction site. This approach aims to reduce construction complexity and improve project execution.
TVA has already undertaken preliminary site preparation. The utility cleared approximately 150 acres, constructed a five-lane bridge and improved access roads.
It also installed onsite electricity and water infrastructure. The NRC previously granted an exemption allowing excavation before construction permit issuance.
Nevertheless, nuclear construction has not officially commenced. TVA has not authorised new construction packages, long-lead procurement or expanded contractor scopes following the permit approval.
The project currently has a potential commercial operation target in the early 2030s. However, TVA has not reaffirmed its earlier 2032 operating target.
The utility has authorised $350 million for Clinch River development activities. Additionally, the Department of Energy selected TVA for up to $400 million in cost-shared federal funding.
TVA continues negotiations with industry partners to distribute project costs and financial responsibilities. The utility wants to protect electricity customers from excessive exposure to first-of-a-kind nuclear technology costs.
Clinch River Nuclear Project strengthens US small reactor pipeline
The construction permit creates an important regulatory precedent for BWRX-300 deployment in the United States. It represents the first US construction permit for this particular reactor design.
The development also adds momentum to America’s expanding small modular reactor pipeline. Other developers are advancing different reactor technologies through separate regulatory pathways.
For instance, the Cascade Advanced Energy Facility in Washington is progressing towards regulatory approval for its initial 320MW nuclear power plant. Energy Northwest, X-energy and Amazon are developing the facility around four 80MW Xe-100 reactors.
Unlike Clinch River, Cascade remains in pre-application discussions with the NRC. Its developers target a construction permit application by the end of 2026.
Meanwhile, TVA’s Clinch River approval demonstrates progress towards commercial deployment of another SMR technology. Both developments seek to provide reliable electricity as demand increases across American industries and data centres.
The next major milestone at Clinch River will involve TVA’s final investment decision. The utility must also complete engineering, procurement and construction preparations before full-scale building activities commence.
Clinch River nuclear project reaches licensing milestone
The NRC received TVA’s first application section in April 2025. TVA submitted the second and final section on May 20, 2025. The submission covered the proposed BWRX-300 construction permit application.
The NRC subsequently conducted detailed environmental and technical reviews. It issued the final supplemental environmental impact statement in April 2026. The document assessed construction and operation impacts for Unit 1.
NRC staff also recommended issuing the construction permit following their safety evaluation. The review found TVA’s application met key regulatory and technical requirements.
The regulator held a mandatory public hearing on August 13. Public comments remained open through August 27, according to the NRC.
Therefore, the anticipated permit would mark a significant step toward nuclear construction at Clinch River.
Clinch River nuclear project advances BWRX-300 construction
The BWRX-300 will generate approximately 300MW using boiling-water reactor technology. Its design uses natural circulation and passive safety systems.
The reactor also uses a modular construction approach. Manufacturers can produce components in factories before assembling them at the project site.
That approach aims to reduce construction complexity, project duration and costs. However, the technology remains relatively unproven commercially outside limited deployments.
Ontario Power Generation began construction of the first BWRX-300 in Canada last year. Meanwhile, only two small modular reactors remain under construction outside China and Russia.
The US project would become only the second commercial small modular reactor to receive a US construction permit. TerraPower received the first such approval for its Wyoming project in March.
The Hermes 2 nuclear reactor project in Oak Ridge is also advancing with support from Samsung C&T and a $100 million investment package. The development adds to Tennessee’s growing pipeline of advanced nuclear projects, alongside the Clinch River nuclear project, which is approaching a separate federal construction approval milestone.
Clinch River nuclear project targets early 2030s operation
TVA expects the initial reactor could enter commercial service in the early 2030s. Earlier project planning has identified 2032 as the potential operating target.
The Clinch River property covers about 1,200 acres along the Watts Bar Reservoir. The designated nuclear site occupies approximately 935 acres.
The site already benefits from existing transmission infrastructure and highway access. TVA also secured the nation’s first early site permit for SMR development there in December 2019.
TVA’s Board has authorized $350 million for Clinch River-related development activities. The Department of Energy separately selected TVA for up to $400 million in federal cost-shared funding.
The federal support will help advance the reactor and strengthen domestic supply-chain capabilities. TVA also plans to work with several nuclear manufacturing and supply-chain companies.
If approved, Clinch River would provide a major US construction test for factory-oriented nuclear technology. The project could also establish a model for subsequent BWRX-300 deployments.
Project Fact Sheet
Project: Clinch River Nuclear Site Unit 1.
Location: Oak Ridge and Roane County, Tennessee, United States.
Type: Small modular nuclear reactor construction.
Reactor technology: GE Vernova Hitachi BWRX-300.
Generation capacity: 300MW electric.
Technology type: Boiling-water small modular reactor.
Construction value: Up to $5.4 billion.
Wider site area: Approximately 1,200 acres.
Designated nuclear site: Approximately 935 acres.
Construction permit application: Submitted to the NRC in May 2025.
NRC environmental review: Final supplemental environmental impact statement issued April 2026.
NRC safety review: Staff recommended construction permit approval.
Early site permit: Issued by the NRC in December 2019.
Potential commercial operation: Early 2030s.
Potential operating target: 2032.
Federal support: Up to $400 million through the US Department of Energy.
TVA authorization: Up to $350 million for Clinch River development activities.
Development objective: Demonstrate deployment of the BWRX-300 in the United States.
Wider development plan: TVA is evaluating up to four BWRX-300 reactors.
Project Team
Owner and project developer: Tennessee Valley Authority (TVA).
Nuclear regulator: US Nuclear Regulatory Commission (NRC).
Reactor technology provider: GE Vernova Hitachi Nuclear Energy.
Project planning and construction partner: Bechtel.
Engineering partner: Sargent & Lundy.
Federal funding partner: US Department of Energy.
Nuclear supply-chain partners: Scot Forge, North American Forgemasters and BWX Technologies.
Additional supply-chain partner: Aecon.
Licensing responsibility: Tennessee Valley Authority and the Nuclear Regulatory Commission.
Site management: Tennessee Valley Authority.
Reactor technology: GE Vernova Hitachi BWRX-300.
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