Dow gets EA/FONSI for Seadrift project

At the end of April, TerraPower announced that it had officially begun construction on its Natrium power plant in Kemmerer, Wyo.-one of the two full-scale demonstration projects in the Department of Energy's Advanced Reactor Demonstration Program.

Now, the second ARDP-backed demonstration project, which aims to see the deployment of X-energy's Xe-100 at a Dow chemical facility, has reached a new milestone of its own. On May 18, X-energy announced that the Nuclear Regulatory Commission has completed its environmental assessment of the proposed Long Mott Generating Facility and issued a finding of no significant impact (FONSI).

A significant change: Despite their similar names, an EA is markedly different than an environmental impact statement, with the former representing a significantly smaller workload than the latter. An EA assesses whether any environmental impact exists, while an EIS entails a longer, full-fledged review.

According to X-energy, this is the first time a commercial advanced reactor project with a 10 CFR Part 50 construction permit application has received an EA rather than an EIS.

Robert Taylor, X-energy's vice president of regulatory affairs and licensing, explained to Canary Media that "the conservative approach has always been to just start with an [EIS], because the perception was the impacts will be big. That's probably true for large light-water reactors, but it's not necessarily true for small modular reactors like us."

The NRC stated in its own May 18 announcement that an EA "better addresses the project's limited environmental footprint at an existing industrial location" and allowed for "more efficient review while maintaining rigorous environmental standards."

The NRC previously stated that if a FONSI had not been reached, it would have commenced the preparation of an EIS. With the determination of a FONSI, however, the regulator has officially achieved a new milestone. NRC Executive Director for Operations Mike King said that this development "demonstrates that we can complete our reviews efficiently, enabling new reactor projects while upholding our responsibility to protect people and the environment."

What comes next: The NRC docketed Dow's construction permit application on May 13, 2025. Per Executive Order 14300, the NRC has an 18-month review timeline for new construction permit applications. The NRC stated that it "expects to complete its safety review of the construction permit application later this year," keeping to that deadline, and that a "final agency decision on the permit would follow."

The NRC also clarified that, if approved, "the construction permit would authorize building the facility but not its operation. The company would need to submit a separate application for operating licenses."

Neither X-energy nor Dow commented on their expected timelines for the submission of an operating license or on the construction or eventual commercial operation of the facility. Notably, last June, Dow media relations director Sarah Young said that Dow "does not expect to make a final investment decision on the project before 2028."

Some background: X-energy frames the Long Mott project as what will become "the first grid-scale advanced nuclear reactor deployed to serve an industrial site in North America." The company wants to build four Xe-100 reactors at Dow's UCC Seadrift Operations, a chemical production facility in Seadrift, Texas, that produces more than 4 billion pounds of materials per year. Those materials include a variety of plastics used in everything from food containers to automotive parts, as well as chemicals used in the pharmaceutical and beauty industries. On-site reactors would provide the plant with both electricity and high-temperature steam.

The Xe-100 is a high-temperature, gas-cooled reactor cooled with pressurized helium gas. Each individual unit is rated at 80 MWe, with a four-pack deployment being rated at 320 MWe. HTGRs like the Xe-100 can produce heat up to 600°C and use TRISO fuel. X-energy, and subsequently Dow, has been involved in preapplication engagement with the NRC regarding the Xe-100 since 2018.