X-Energy Inc. (NASDAQ: XE) submitted an application to enter the United Kingdom's Generic Design Assessment process for its Xe-100 High Temperature Gas-cooled Reactor, according to a company statement.

The Generic Design Assessment is the UK's regulatory pathway for licensing new nuclear technologies, evaluating safety, security, safeguards, and environmental impact. The assessment will be administered by the UK Office for Nuclear Regulation, Environment Agency, Natural Resources Wales and the Department for Energy Security and Net Zero. The process is expected to conclude by the end of 2029.

X-Energy has been in dialogue with UK regulatory authorities since 2024 through an Early Engagement process. The company said the submission builds on its U.S. licensing progress and is expected to benefit from expanded collaboration between the UK Office for Nuclear Regulation and the U.S. Nuclear Regulatory Commission that allows for direct transfer of design documentation and safety analyses.

The Xe-100 is an 80 MWe reactor deployed in four-or-twelve-unit plants, capable of providing electricity and high-temperature heat and steam for industrial applications. In September 2025, X-Energy and Centrica signed a Joint Development Agreement targeting 6 GW nationwide, with Hartlepool identified as the preferred first site for a 12-unit/960 MWe Xe-100 plant.

"Advanced Modular Reactors like the Xe-100 are the cornerstone of Britain's future energy security, and would bring clean, reliable power as well as renewed opportunities for British industry," said Alistair Black, Vice President and UK Market Lead at X-energy.

The United Kingdom currently operates eight Advanced Gas-Cooled Reactors. In 2024, X-Energy was selected for the Department for Energy Security and Net Zero's Future Nuclear Enabling Fund to develop UK-specific deployment plans.