This marks a key milestone in the review process for the proposed project which would see four X-energy Xe-100 high-temperature gas reactor units built at Dow’s Seadrift site, the US Nuclear Regulatory Commission (NRC) said.
Long Mott Energy LLC – a wholly owned subsidiary of Dow – submitted the construction licence application in March 2025, and the NRC began its environmental review in June. The regulator – which is working to streamline the route to deployment of advanced reactor technologies at the direction of executive orders signed by President Donald Trump last year – determined that an environmental assessment (EA), rather than a more extensive environmental impact statement (EIS), better addresses the project’s limited environmental footprint at an existing industrial location. This approach allows for a more efficient review while maintaining rigorous environmental standards, the NRC said.
“This milestone demonstrates that we can complete our reviews efficiently, enabling new reactor projects while upholding our responsibility to protect people and the environment,” said NRC Executive Director for Operations Mike King. “Using an environmental assessment in this case reflects the project’s relatively low potential for environmental impacts and helps provide a more predictable path forward.”
The NRC concluded that the potential environmental impacts from the construction of the Long Mott Generating Station “would not be significant” and has determined that a “Finding of No Significant Impact is warranted, and … the preparation of an EIS is not required”.
The Finding of No Significant Impact conclusion on the environmental assessment follows an extensive independent analysis by NRC staff, evaluating potential impacts to air quality, water resources, and local species habitats under globally recognised safety and environmental standards. The NRC’s environmental review, completed in less than a year, benefitted from X-energy’s pre-licensing work on the Xe-100 and the comprehensive construction permit application which included an in-depth environmental report supported year-long field surveys, groundwater monitoring wells with 12 months of water quality measurements, and engagement with multiple state agencies including the Texas Historical Commission, Texas Parks and Wildlife Department, and Texas General Land Office, X-energy said.
“This is a significant milestone for the Long Mott Energy project and we appreciate the comprehensive and efficient manner in which the NRC conducted its assessment,” said Edward Stones, business vice president, Energy & Climate, Dow. “We are another step closer to expanding access to safe, clean, reliable, cost-competitive nuclear energy in the US.”
The NRC said it expects to complete its safety review of the construction permit application later this year, consistent with the 18-month timeline required by Executive Order 14300. A final agency decision on the permit would follow. The construction permit would authorise building the facility, but the company would need to submit a separate application for licences to operate the plant.
Long Mott Generating Station is tipped to be the first grid-scale advanced nuclear reactor deployed to serve an industrial site in North America. The Xe-100 units are engineered to operate as a single 80MW electric unit, and are optimised as a four-unit plant delivering 320 MWe: the reactor can provide baseload power to an electricity system or support industrial applications with 200 MW thermal output per unit of high-pressure, high-temperature steam.
Dow is one of several tech giants and other major energy users to have signed the Large Energy End Users Pledge, supporting the goal of at least tripling nuclear energy by 2050. The Long Mott project is expected to reduce emissions from the Seadrift site – which manufactures more than 4,000,000 pounds (1816 tonnes) of materials per year for use in applications such as food packaging, footwear, wire and cable insulation, solar cell membranes and packaging for pharmaceutical products – by about the equivalent of 440,000 tonnes of carbon dioxide per year.
