Centrica (LSE:CAN) and X-Energy (NASDAQ:XE) said the Xe-100 small modular reactor has been accepted into the UK’s Generic Design Assessment process, beginning a regulatory review expected to take approximately three years.
The Generic Design Assessment, or GDA, examines whether a nuclear reactor design is acceptable for deployment in the UK before site-specific licensing and permitting can proceed.
The review will be carried out by the Office for Nuclear Regulation, the Environment Agency and Natural Resources Wales.
Centrica and X-energy Target Up to 6 GW
Centrica and X-energy entered into a partnership in September 2025 covering the potential deployment of up to 6 gigawatts of new nuclear capacity in the UK.
The companies estimate this could involve between 10 and 20 Xe-100 power stations, depending on the configuration and capacity of individual sites. Hartlepool has been identified as the proposed location for the first project.
Since signing the agreement, the companies said they have started site studies and planning work in Hartlepool alongside workforce-development initiatives, including a Nuclear and Electrical Trades Academy.
Xe-100 Designed for Electricity and Industrial Heat
The Xe-100 is a high-temperature gas-cooled reactor. Each unit is designed to produce 80 megawatts of electricity or 200 megawatts of thermal energy for industrial applications.
X-energy plans for the reactors to operate in multi-unit configurations providing between 320 MW and 960 MW of capacity.
The companies said the UK assessment is expected to draw on cooperation between British regulators and the US Nuclear Regulatory Commission, including the transfer of previously reviewed design documentation and safety analyses between the two jurisdictions.
X-energy Developing US Projects
X-energy is separately working on an initial Xe-100 project with Dow Inc. on the Texas Gulf Coast.
The company is also developing another project with Energy Northwest in collaboration with Amazon.
UK Minister of State for Energy Michael Shanks described acceptance into the regulatory process as “another important step towards bringing advanced nuclear technologies to the UK”.
He said projects of this type could provide “clean, secure and homegrown energy” while supporting investment and employment in Hartlepool.