The US Nuclear Regulatory Commission announced in December that it has authorised the issuance of an Early Site Permit for Tennessee Valley Authority’s (TVA’s) Clinch River site near Oak Ridge, Tennessee.

The permit closes several site-related issues, including many environmental impacts, for small modular reactors at the site. NRC authorised the agency’s Office of Nuclear Reactor Regulation to issue the permit following a hearing in August.

The Commission found the staff’s review of TVA’s application adequate to make the necessary regulatory safety and environmental findings. The permit, which will be valid for up to 20 years, does not authorise any NRC-regulated construction activities. TVA would need to apply separately for an NRC licence to build and operate a reactor at the site.

The permit includes additional provisions, including approved analysis methods, that deal with  NRC’s emergency preparedness regulations. This could allow a future licence applicant at the Clinch River site to request an emergency preparedness zone smaller than those found at current US nuclear plants.

NRC’s technical review also covered issues such as how the site’s characteristics could affect plant safety and environmental protection considerations. A final environmental impact statement for the permit was issued in April and a final safety evaluation in June.

Potentially, TVA could be the first US utility approved to build and operate small modular reactors (SMRs). However, TVA said it has no plans to build such a reactor, although the permit "will give [it] flexible options to prepare for future energy needs”. “The early site permit is a significant step in the potential development of small modular reactor technology,” Dan Stout, director of nuclear technology innovation at TVA, said in a statement. TVA applied for the permit in 2016, and NRC began its formal review in January 2017.

TVA has until 2039, with the possibility of an extension, to decide whether to go ahead with SMR construction. “The decision to build will be based on energy needs and economic factors,” said TVA chief nuclear officer Tim Rausch. “SMRs are more attractive where load growth is slow, and they provide a more affordable option than the higher up-front capital costs associated with larger nuclear facilities,” Stout explained.

The Nuclear Energy Institute (NEI) welcomed the development. “By revising its process for establishing the size of the emergency planning zone based on the type of advanced reactor developed, the NRC is demonstrating its commitment to evolving regulations, so they align with the size and inherent safety features of advanced nuclear technologies," the NEI's chief nuclear officer Doug True said in a statement.

Photo: NRC Commission holding a mandatory hearing on the Tennessee Valley Authority’s application for an Early Site Permit at the Clinch River site in Tennessee in Rockville, Md.