The US Nuclear Regulatory Commission (NRC) has published its final safety evaluation report on Tennessee Valley Authority's (TVA's) application for an early site permit (ESP) for the potential use of a site at Clinch River for two or more small modular reactors. The regulator concluded there are no safety concerns to prevent issuing such a permit.

The proposed Clinch River site in Tennessee (Image: TVA)

An ESP certifies that a site is suitable for the construction of a nuclear power plant from the point of view of site safety, environmental impact and emergency planning, but does not specify the choice of technology. The permit is valid for ten to 20 years, renewable for an additional ten to 20 years.

TVA submitted its ESP application for the Clinch River site to the NRC in May 2016. The application is for two or more small modular reactor (SMR) modules of up to 800 MWe at the 1200 acre (486 hectare) site near the Department of Energy's (DOE's) Oak Ridge National Laboratory. The proposed site hosted the former Clinch River Breeder Reactor Project. The NRC accepted the application for regulatory review in December of that year. It was the first SMR-related application of any type to be received by the NRC.

The NRC has now published its final safety evaluation report (FSER) on TVA's application. This, it said, "documents the staff's conclusions with respect to the ESP safety review and identifies items to be addressed by a future COL or construction permit applicant referencing the Clinch River Nuclear Site ESP."

Earlier this year, the NRC concluded there are no environmental impacts that would preclude issuing an ESP for Clinch River. With the publication of its safety review, the NRC's technical review of TVA's application is now complete.

SMR units, typically with a capacity of 300 MWe equivalent or less, are designed using modular technology and factory fabrication. This allows for economies of series production and short construction times. Multiple units can be installed at one location to provide the total required capacity. Such reactors are seen as potentially offering improved safety and security, as well as more standardisation, more site options and lower financing costs compared to conventional light-water reactors. TVA says SMRs could provide an important option for clean baseload energy for its generation portfolio.

The DOE is supporting the development and commercialisation of SMRs, which it sees playing an important role in addressing the country's energy security, economic and climate goals. TVA's ESP application has been developed with the support of the DOE SMR Licensing Technical Support program, which has also provided cost-shared financial assistance through an interagency agreement. The five-year agreement, finalised in July 2015, will also support a combined construction and operating licence (COL) application.

US government-owned TVA operates the Browns Ferry, Sequoyah and Watts Bar nuclear power plants.