X-energy, the Maryland-based small modular reactor developer that went public on Nasdaq under the XE ticker, submitted an application on June 2, 2026 to enter the United Kingdom's Generic Design Assessment process for its Xe-100 high temperature gas-cooled reactor. Subject to acceptance, the filing kicks off the formal multi-year UK licensing path for what X-energy and Centrica have agreed will be up to 6 gigawatts of fleet-scale nuclear capacity in Britain.
What The GDA Means
Generic Design Assessment is the UK's established regulatory pathway for licensing new reactor designs, evaluating safety, security, safeguards and environmental impact independent of site-specific considerations. The assessment is administered jointly by the Office for Nuclear Regulation, the Environment Agency, Natural Resources Wales and the Department for Energy Security and Net Zero. X-energy expects the review to conclude by the end of 2029. The Xe-100 is an 80 MWe HTGR designed to deploy in four or twelve-unit plants and is capable of producing high temperature heat and steam for industrial loads, not just electricity.
NRC Data Carries Across The Atlantic
Alistair Black, X-energy's UK market lead, said the company has been in active dialogue with British regulators since 2024 through the Early Engagement process. The UK submission builds on the design's progress under the U.S. Nuclear Regulatory Commission and is expected to benefit from an expanded ONR-NRC cooperation agreement that allows direct transfer of design documentation and safety analyses between the two regulators. That is a quietly significant detail. It means X-energy will not have to re-create its safety case from scratch in Britain, which has historically been one of the bigger costs of pursuing parallel licensing tracks.
Centrica, Hartlepool And A 6 GW Plan
The submission is the next concrete step in the X-energy and Centrica Joint Development Agreement signed in September 2025. The partners are targeting 6 GW of new nuclear nationwide, with Hartlepool identified as the preferred first site for a twelve-unit, 960 MWe Xe-100 plant. The project is advancing through the UK Government's Advanced Nuclear Pipeline assessment. In 2024 X-energy was selected for DESNZ's Future Nuclear Enabling Fund, and subsequent studies estimated at least 40 billion pounds in lifetime economic value, including 12 billion from the first project alone. The push also fits into a broader U.S. SMR commercial cycle that has included X-energy's Kentucky and Pennsylvania utility agreements and SPAC-route plans like Newcleo's Nasdaq SPAC listing.
Reporting based on coverage from X-energy, GlobeNewswire, World Nuclear News and BusinessWire.