The Nuclear Regulatory Commission has issued a construction permit for Dow’s proposed four-unit Xe-100 facility at Seadrift, Texas, while Dow continues its phased review ahead of an expected preliminary investment decision in 2027.
Published by Allstream Insiders
Allstream Insiders Summary
Dow subsidiary Long Mott Energy has received a U.S. Nuclear Regulatory Commission construction permit for the proposed Long Mott Generating Station at Dow’s UCC Seadrift Operations site in Calhoun County, Texas. According to X-energy’s November 9 announcement, the project would use four Xe-100 advanced small modular reactor units to provide electricity and high-temperature steam to the industrial site.
The permit completes the NRC’s safety and environmental review of the construction-permit application. It is a material regulatory milestone, but it does not authorize operation, establish a final investment decision or confirm that full-scale construction has begun.
Dow and X-energy said they will next continue design standardization, supply-chain development for long-lead materials and components, and operating-license work. Dow is expected to consider a preliminary investment decision in 2027; full-scale nuclear construction would follow a later final investment decision, according to the companies.
Long Mott Generating Station at a Glance
| Item | Company- or regulator-reported detail |
|---|---|
| Permit recipient | Long Mott Energy, LLC, a wholly owned Dow subsidiary |
| Location | Dow UCC Seadrift Operations site in Calhoun County, Texas |
| Plant configuration | Four proposed Xe-100 high-temperature gas-cooled reactor units |
| Unit rating | 80 MWe and 200 MWt per reactor, according to X-energy |
| Proposed total output | Up to 320 MWe and 800 MWt across four units, calculated from X-energy’s stated unit ratings |
| Intended use | Electricity and high-temperature steam for Dow’s Seadrift industrial site |
| Next investment milestone | Dow expects to consider a preliminary investment decision in 2027 |
| Full-scale construction | Would follow Dow’s final investment decision; no start date was disclosed |
What the construction permit authorizes
The construction permit gives Long Mott Energy federal approval to build the proposed facility in accordance with the design approved in the permit. The NRC’s Long Mott project record identifies the application as a four-reactor Xe-100 facility at the Dow Chemical Seadrift site.
That authorization is distinct from permission to operate the plant. Before fuel loading and startup, the project would need an NRC operating license. X-energy said Dow and its technical teams will use the next phase to advance engineering, construction readiness and the operating-license application.
The companies characterized the permit as the first approval of an advanced nuclear facility at a U.S. industrial site. X-energy also said it is the first NRC construction-permit approval for a high-temperature gas-cooled reactor in nearly 60 years. Those are milestone claims from the companies’ announcement, not a declaration that the facility is already under full-scale construction.
The project is designed for industrial power and steam
Long Mott is proposed as an industrial energy-and-steam project rather than solely a grid-power plant. The four-unit facility is intended to replace existing energy and steam assets near the end of their operating life at Dow’s Seadrift complex.
X-energy describes each Xe-100 as an 80-megawatt-electric, 200-megawatt-thermal reactor. On that basis, the four-unit proposal equates to 320 MWe of electric capacity and 800 MWt of thermal capacity. The companies did not disclose the project’s total cost, a unit-by-unit construction sequence, a detailed steam-integration scope, an equipment list or commercial terms for the proposed facility.
Investment decision and schedule remain ahead
The permit does not replace Dow’s internal capital-approval process. X-energy said Dow is expected to consider a preliminary investment decision in 2027, while full-scale nuclear construction would occur only after a final investment decision. The companies continue to cite first delivery in the early 2030s as their established target.
Those milestones remain forward-looking. The announcement does not provide a final investment decision date, construction-start date, commercial-operation date, project budget or construction contract awards. It also does not confirm that all suppliers, financing arrangements or operating-license requirements are in place.
Allstream perspective: Regulatory clearance creates a clearer path to execution
Allstream perspective: The construction permit is a meaningful transition from regulatory review into construction readiness for a first-of-a-kind industrial nuclear project. If Dow advances to final investment decision, potential work categories could include detailed engineering and design; long-lead nuclear and conventional-island equipment; structural steel and concrete; electrical and instrumentation systems; high-temperature steam integration; piping, valves and fittings; modular fabrication; civil work; insulation and coatings; quality assurance; testing; and commissioning.
These are potential categories for a project of this type—not awarded scopes or confirmed procurement packages for Long Mott. The most important next signals for the industrial market will be Dow’s investment decisions, operating-license progress, final design milestones, named suppliers, engineering awards, long-lead purchase orders and a confirmed construction schedule.
