U.S. NRC Completes Safety Review of Dow's 320 MW Long Mott Nuclear Project

en.Wedoany.com Reported - On October 30, U.S. nuclear technology company X-energy confirmed that the U.S. Nuclear Regulatory Commission (NRC) has completed the Final Safety Evaluation Report (FSER) for the construction permit application of Dow Chemical's Long Mott nuclear project. Located in Calhoun County, Texas, the project plans to build four Xe-100 high-temperature gas-cooled reactors with a total design electrical output of 320 MW and thermal output of 800 MW. With the completion of this safety evaluation, the project has entered the final stage of construction permit review, pending a formal licensing decision by the NRC.

The Long Mott nuclear project is being developed by Long Mott Energy LLC, a wholly-owned subsidiary of Dow Chemical, and is planned for construction at Dow's Seadrift chemical production site, with X-energy responsible for supplying the Xe-100 reactor technology. Each of the four reactors has a design electrical output of approximately 80 MW and a thermal output of 200 MW. The project plans to use nuclear energy to supply electricity and industrial heat to chemical production facilities.

The Final Safety Evaluation was conducted in accordance with Title 10, Part 50 of the U.S. Code of Federal Regulations. NRC staff reviewed the principal design criteria of the reactors, preliminary design, safety analyses, probabilistic risk assessment, and related research and development programs. The Final Safety Evaluation Report concludes that the proposed plant and its site provide an adequate technical basis to support a safety determination for the construction permit, providing the basis for the project to proceed to the final licensing decision process.

The U.S. Advisory Committee on Reactor Safeguards (ACRS) has independently reviewed the NRC staff's safety evaluation and supports issuance of the construction permit. The committee's review findings, together with the NRC staff's Final Safety Evaluation, constitute an important basis for the project's construction permit decision.

The Xe-100 features a helium-cooled, pebble-bed core design with TRISO-X coated particle fuel. In this licensing review, X-energy proposed an emergency planning zone of approximately 400 meters and incorporated fuel coating layers, passive safety features of the reactor, and defense-in-depth measures into its safety case. The company believes these design conditions can support a relatively compact industrial site layout. The emergency planning zone scope remains related to the safety evaluation and regulatory decision of the specific project and cannot be directly applied to other Xe-100 projects.

The environmental review of the Long Mott project was completed in May 2026, with the NRC issuing a Finding of No Significant Impact (FONSI). With the completion of the Final Safety Evaluation, both major technical reviews—safety and environmental—involved in the construction permit application have been concluded. The NRC still needs to complete the final licensing decision, and subsequent operation of the project will require a separate operating license.