First Industrial Advanced Reactor Permit in Decades
The U.S. Nuclear Regulatory Commission approved a construction permit on November 9, 2026, for Dow and X-energy's Long Mott Generating Station at Dow's Seadrift chemical site in Texas. The decision represents the first advanced nuclear facility authorized at a U.S. industrial site. It is also the first NRC construction permit for a high-temperature gas-cooled reactor in over 50 years and the first-ever approval for a pebble-bed core design. The permit covers four X-energy Xe-100 small modular reactors, each rated at 80 megawatts of electricity or 200 megawatts of thermal energy; together, the units can supply up to 320 megawatts of power and industrial steam over a projected 60-year lifespan. The facility is designed to replace aging fossil-fueled power and steam assets.
The NRC completed its review in 18 months. NRC Chairman Ho K. Nieh said the agency delivered on its 18-month schedule while maintaining rigorous safety evaluations. Backed by the Energy Department's Advanced Reactor Demonstration Program, the facility uses TRISO-X coated particle fuel spheres designed to retain radioactive material under extreme conditions. In September 2026, X-energy subsidiary TRISO-X finished vertical construction on its Oak Ridge, Tennessee, fuel fabrication plant, the first commercial-scale high-assay low-enriched uranium fuel facility approved in the United States.
Obtaining the construction permit clears a major regulatory hurdle, though actual groundbreaking remains contingent on corporate capital decisions. Dow is expected to evaluate a preliminary investment decision in 2027, followed by a final investment decision before full-scale building starts. A separate NRC operating license will also be required before generating power. Initial energy delivery is targeted for the early 2030s. Beyond Texas, Maryland-based X-energy is pursuing nuclear projects in Washington state alongside Fluor and in the United Kingdom with Centrica, where the Xe-100 entered generic design assessment in September 2026.
