RELEASE: The NRC Approves Construction Permit for TVA’s Clinch River Small Modular Reactor

WASHINGTON, DC, September 29, 2026 — Today, the U.S. Nuclear Regulatory Commission (NRC) issued a construction permit to the Tennessee Valley Authority (TVA) for a BWRX-300 small modular reactor at the Clinch River Nuclear Site in Tennessee—the first construction authorization for a commercial small modular reactor in the United States. 

The NRC completed its review in 14 months—four months ahead of schedule—after concluding that TVA’s application met applicable safety requirements. The permit is the NRC’s second major new-reactor construction approval in 2026, following the Terrapower Natrium construction permit issued in March. Both reviews were completed ahead of schedule, signaling improved licensing efficiency across different advanced reactor designs as the agency works to execute its new mission to enable nuclear technologies for the benefit of society.

The efficient review was enabled in part by TVA previously receiving an Early Site Permit for the Clinch River site with a combined limit of 800 MWe. An Early Site Permit allows the owner to pre-qualify a site for later development when a reactor design has been selected.

“Clinch River shows that pre-qualifying a site with an Early Site Permit can be an effective approach. Future applicants and even states can leverage this tool when they know where they need power,” said Adam Stein, Director of Nuclear Energy Innovation at the Breakthrough Institute. “This shortens the future permitting review, while driving site selection to the preferred locations.” 

“Clinch River is an important signal toward efficient reviews becoming routine rather than the exception. But predictability matters as much as speed,” Stein said. “Applicants need to know what information the NRC expects, when decisions will be made, and that the review will remain focused on what issues matter to public health and safety. The next challenge is making efficient licensing repeatable across a growing pipeline of various kinds of reactor applications.”

The decision allows TVA to move forward with construction of the 300 MWe reactor but does not authorize TVA to operate the reactor. TVA must complete construction and obtain a separate operating license from the NRC before it can load fuel or begin operation.

###

Media Contact:

Adam Stein

Director of Nuclear Energy Innovation

adam@thebreakthrough.org