GE Vernova Hitachi has reached a major regulatory milestone with its BWRX-300 modular reactor, now deemed suitable for construction in the United Kingdom. This follows the completion of Step 2 of the Generic Design Assessment (GDA) process, conducted by the Office for Nuclear Regulation, the Environment Agency and Natural Resources Wales. The consortium chose to follow a shortened two-step GDA path, making it the first to do so under the revised procedure.
A compact and standardised reactor model
The BWRX-300 is a 300 MWe boiling water reactor using passive safety systems and natural circulation. It is based on the design of the ESBWR reactor previously developed by General Electric Hitachi Nuclear Energy. According to regulators, there are no major gaps in safety, security or environmental protection that would prevent its deployment in Britain.
Step 1 of the GDA began in January 2024 and defined the scope of the evaluation. Step 2, now concluded, focused on reviewing technical documents relating to safety, security, nuclear safeguards and environmental protection. The accelerated assessment was enabled by the quality of the submitted materials and coordination between UK authorities and their counterparts in North America.
Regulatory acceptance without deployment plans
There are currently no plans to construct the BWRX-300 in the United Kingdom and no site has been identified. A further assessment would be required should a developer opt to proceed with this reactor design. This could be conducted through Step 3 of the GDA or as part of a site-specific review with a licence holder or constructor.
Regulators highlighted the rigour of the process despite its shorter timeline. It is the first project to benefit from the new two-step GDA structure, with the timeline shortened due to the maturity of the design documentation and learnings from previous assessments.
Increasing competition in the SMR market
Several other small modular reactor designs are currently undergoing assessment in the United Kingdom, including those from Rolls-Royce SMR Limited and Holtec International. Additional designs, such as Westinghouse’s AP300 and TerraPower’s Natrium, are also under review or have submitted for GDA consideration.
This regulatory momentum reflects growing interest in compact, standardised nuclear technologies, although future deployment remains subject to commercial and policy decisions.
