NRC Issues First US Construction Permit for a BWRX-300: TVA's Clinch River Unit 1

NRC Issues First US Construction Permit for a BWRX-300: TVA's Clinch River Unit 1

On September 29, 2026, the Nuclear Regulatory Commission issued the construction permit for Clinch River Unit 1 — a 300 MW GE Vernova Hitachi BWRX-300 small modular reactor at TVA's Clinch River Nuclear Site near Oak Ridge, Tennessee. Per ANS: "Today, the Nuclear Regulatory Commission approved the Tennessee Valley Authority's construction permit application for its planned GE Vernova Hitachi BWRX-300 at the Clinch River site in Oak Ridge, Tenn."

This is the first US construction permit ever issued for a BWRX-300, and per neutronbytes "only the second advanced reactor construction permit ever issued in the nation." The review path: an NRC safety evaluation completed in June "found that TVA's construction permit application met all regulatory requirements," and TVA already holds an early site permit for SMRs at Clinch River. World Nuclear News notes the commercial caveat: "although no construction date has been announced, it is now the first US utility permitted to construct the BWRX-300 small modular reactor."

Why it matters: this is the first concrete NRC authorization converting SMR paper into a buildable project, and TVA is emerging as the US nuclear deployment bellwether — the same utility anchoring the ENTRA1/NuScale 6 GW framework (watch: "NuScale and ENTRA1 sign definitive PPA with TVA"). The permit also gives the BWRX-300 line (GE Vernova Hitachi) a first-mover regulatory advantage over US SMR developers still in pre-permit stages, including Oklo and Nano Nuclear.¹