RELEASE: NRC Issues Construction Permit for X-energy's Advanced Reactor Project in Texas

WASHINGTON DC, November 9, 2026  — The Nuclear Regulatory Commission (NRC) has issued a construction permit for the Long Mott Generating Station in Texas, marking the first approval of a high-temperature gas-cooled reactor in nearly 60 years and the third advanced reactor construction permit issued in 2026. The four planned X-energy Xe-100 reactors will supply industrial steam and electricity to Dow's Seadrift Operations site, with excess electricity delivered to the grid.

Beyond the approval itself, the project demonstrates important progress in risk-informed licensing and regulatory efficiency. The NRC completed an Environmental Assessment tailored to the project’s actual impacts in May and issued a Finding of No Significant Impact, avoiding a time-intensive and costly Environmental Impact Statement. And, due to the functional safety features of the Xe-100 design, the NRC approved a substantially smaller emergency planning zone (EPZ) of 400 meters, compared with the traditional 10-mile EPZ for large light-water reactors. 

Importantly, the NRC completed its comprehensive safety evaluation in October, one month ahead of schedule, and issued the construction permit within its established 18-month review timeline. The approval also represents several regulatory firsts, including the agency's first approval of a pebble-bed core and online refueling design.

“This is an important milestone for X-energy and for the NRC,” said Adam Stein, Director of Nuclear Energy Innovation at the Breakthrough Institute. “With this review completed, the NRC has shown that it can execute rigorous safety and environmental evaluations for multiple new reactor designs on predictable and commercially viable timelines. These are important steps toward a regulatory framework that reflects the characteristics of advanced reactors. Making this approach routine will be essential to deploying advanced nuclear energy at scale for both electricity and industrial heat.”

Together, these milestones demonstrate that rigorous safety oversight, proportionate regulatory requirements, and predictable licensing timelines can be achieved simultaneously. The permit authorizes construction, with a separate operating license required before the reactors can begin operation.

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Media Contact:

Adam Stein

Director of Nuclear Energy Innovation

adam@thebreakthrough.org