NRC Completes Safety Review for Xe-100 Plant in Texas, Clearing Path to Construction Permit
Safety Review Milestone Reached
The US Nuclear Regulatory Commission released its Final Safety Evaluation Report for the Long Mott Generating Station construction permit application on 30 October. The report covers the NRC staff's assessment of the plant's principal design criteria, preliminary design, safety analyses, probabilistic risk assessment, and associated research and development programmes. The staff concluded that the proposed plant and site provide an adequate safety basis to proceed with construction under applicable US nuclear regulations.
The NRC had previously completed its environmental review in May, when it issued an Environmental Assessment and Finding of No Significant Impact. With both the safety and environmental reviews now finalised, the project has advanced to the final stages of the NRC's construction permit review process. The regulator indicated via its social media channels that a construction permit announcement should be expected shortly.
Project Overview
Long Mott Energy, a wholly owned subsidiary of The Dow Chemical Company, submitted the construction permit application in March 2025. The proposed facility would consist of four Xe-100 high-temperature gas-cooled reactors with a combined thermal output of 800 MWt, equivalent to 320 MWe of electrical capacity. The plant is intended to supply electricity and process steam to Dow Chemical's Seadrift Operations in Texas, with any surplus power exported to the wider electrical grid.
X-energy has described the project as the first grid-scale advanced nuclear reactor proposed for deployment at an industrial facility in US history. The Xe-100 is also the first high-temperature gas-cooled reactor construction permit application to be reviewed under the NRC's technology-inclusive, risk-informed, and performance-based licensing framework, a regulatory pathway designed to accommodate non-light-water reactor designs.
Regulatory and Technical Background
X-energy's commercial licensing effort has been supported by pre-application engagement with the NRC dating back to 2018, alongside decades of US Department of Energy research into high-temperature gas-cooled reactor technology. The combination of early regulator engagement and a novel licensing framework has shaped the review process for the Xe-100 application.
Dragan Popovic, Chief Global Operating Officer at X-energy, noted that the NRC's completion of the safety review reflects sustained effort by both the company's team and NRC staff, and that the foundations established through this process are intended to support future Xe-100 applications as the technology moves toward broader deployment.