The UK government has directed nuclear regulators to accept X-energy's Xe-100 Advanced Modular reactor design into the Generic Design Assessment (GDA), the formal review that leads to UK commercial licensing. The move came on the one-year anniversary of the Centrica X-energy partnership's September 2025 signing, under which the two companies intend to deploy up to 6 GW of new nuclear power capacity in the UK, enough for 10 to 20 Xe-100 stations depending on the size of each installation.
GDA acceptance triggers a formal assessment of whether the reactor design is acceptable for deployment and operation in the UK, ahead of the separate technical and environmental reviews needed for site-specific licensing and permitting. The UK Office for Nuclear Regulation, the Environment Agency and Natural Resources Wales will run the assessment, expected to take about three years. The submission is expected to benefit from expanded collaboration between UK regulators and the US Nuclear Regulatory Commission, which would let NRC-reviewed design documentation and safety analyses feed into the UK review.
What the executives said
Centrica group chief executive Chris O'Shea called the acceptance a milestone that reflects the partnership's progress over its first 12 months, and said nuclear "has a critical role to play" in the UK's energy and national security. O'Shea said deploying up to 6 GW of capacity would create "tens of billions" in economic value and thousands of skilled jobs, starting at Hartlepool. X-energy chief executive J. Clay Sell said the project is moving from a first plant at Hartlepool toward "a fleet of Xe-100 plants across the country," and pointed to the UK's "industrial capability, nuclear expertise and policy ambition to lead" advanced nuclear deployment. Minister of State for Energy Michael Shanks said the projects "will help us deliver clean, secure and homegrown energy" while bringing investment and jobs to Hartlepool and the UK supply chain.
Timeline and next steps
Centrica and X-energy signed their initial agreement in September 2025, announced during President Donald Trump's state visit to the UK. Since then the companies have carried out early project work, including formal engagement with nuclear regulators, site studies with specialist firms, and a proposal for entry into the UK government's Advanced Nuclear Pipeline, with results expected soon. The companies have also worked with local bodies in Hartlepool on workforce training, including opening a Nuclear and Electrical Trades Academy.
Reactor specs and other projects
Each Xe-100 unit is designed to generate 80 MW of electricity, or 200 MW of thermal heat for industrial use, and is built into multi-unit plants ranging from 320 MW to 960 MW. X-energy is also advancing an Xe-100 plant with Dow Inc. on the Texas Gulf Coast and developing a separate plant with Energy Northwest in collaboration with Amazon. The companies have framed the UK as a natural second market for the Xe-100 and its TRISO-X fuel, pointing to the UK's history in gas-cooled reactor technology and the regulatory experience of the ONR and Environment Agency in that area. TRISO fuel technology traces its origins to earlier British nuclear research, according to the companies.
