X-Energy this week submitted an application for its Xe-100 small modular reactor to the United Kingdom’s Generic Design Assessment process.
The company is developing the Xe-100 reactor, which is a high-temperature gas-cooled SMR capable of producing 80 megawatts of electricity. The reactor, which is also being reviewed by the Nuclear Regulatory Commission in the United States, is designed to operate as a four-pack power plant that generates 320 megawatts.
Xe-100 SMR will also use tri-structural isotropic, also known as TRISO, fuel to power it.
“[The] GDA [Generic Design Assessment] submission marks an important milestone in bringing our technology to the UK on a fleet-scale, with the potential to create thousands of high-quality jobs where needs are greatest,” Alistair Black, X-Energy vice president and UK market lead, said in its Tuesday press release.
“We welcome the regulators’ recent steps towards a more efficient GDA process, and look forward to working collaboratively to support an efficient, thorough review,” Black added.
The Generic Design Assessment is the UK’s regulator pathway for licensing new nuclear technologies. The evaluation is governed by the UK Office for Nuclear Regulation, Environment Agency, Natural Resources Wales and the Department for Energy Security and Net Zero and is expected to be completed by the end of 2029, according to the release.
X-Energy said it has been in contact with UK regulatory authorities since 2024 through the early engagement process. The company added that the submission builds on the progress the company has made in the NRC’s review process.
The company also expects to further benefit from “expanded collaboration between ONR [UK Office of Nuclear Regulation] and the U.S. Nuclear Regulatory Commission that allows for direct transfer of design documentation and safety analyses,” according to the release. This streamlined approach allows applicants to leverage NRC-approved technical documents throughout the assessment.
X-Energy pursues regulatory approval in the UK for its reactor after announcing plans in September 2025 with Centrica to bring up to 6,000 megawatts in generation for a planned fleet at Eléctricité de France (EDF) and Centrica’s Hartlepool nuclear power plant site in Hartlepool, England.