The U.S. Nuclear Regulatory Commission has issued a construction permit for Dow's Long Mott Generating Station in Seadrift, Texas, a 320 MWe project built around four X-energy Xe-100 reactors, the American Nuclear Society's Nuclear Newswire reported on November 10, 2026. The permit went to Long Mott Energy, a Dow subsidiary.
The decision carries several firsts. It is the first construction permit for a high-temperature gas-cooled reactor in nearly 60 years, the first U.S. approval of a pebble-bed design of that type, and the first NRC construction permit for a reactor located at an industrial site.
Each Xe-100 unit is rated at 80 MWe and 200 MWt. The reactors use HALEU TRISO fuel particles packed into graphite pebbles and are cooled with helium. The plant would supply both electricity and high-temperature steam to Seadrift, Dow's second-largest site in Texas, and the companies expect the reactors to serve the site for 60 years.
The NRC reached the decision within its 18-month review target. "This is an important day," said X-energy chief executive Clay Sell.
A permit does not guarantee construction. Dow and X-energy say a final decision has not been made, and engineering work and a review by Dow's board of directors remain. A preliminary investment decision is expected in 2027, with commercial operation possible in the early 2030s if the project moves forward. An NRC operating license would also be required.
Long Mott is one of two full-scale demonstrations under the Department of Energy's Advanced Reactor Demonstration Program, alongside TerraPower's Natrium plant in Wyoming, and has received roughly $2.15 billion in cost-shared DOE funding. It is the third NRC construction permit of 2026, following Natrium in March and a GE Vernova Hitachi BWRX-300 at the Clinch River site in Tennessee in September.
Source: ANS Nuclear Newswire -- https://www.ans.org/news/2026-11-10/article-8573/nrc-issues-construction-permit-for-dowxenergy-long-mott-project/