Generic Design Assessment (GDA) is a process carried out by the Office for Nuclear Regulation (ONR), the Environment Agency and Natural Resources Wales to assess the safety, security, and environmental protection aspects of a nuclear power plant design that is intended to be deployed in Great Britain. The GDA process is a voluntary, non-mandatory process. Successful completion of the three-step GDA culminates in the issue of a Design Acceptance Confirmation from the ONR and a Statement of Design Acceptability from the Environment Agency. In May 2021, the UK’s Department for Business, Energy and Industrial Strategy opened the GDA process to advanced nuclear technologies, including small modular reactors (SMRs).
GE Vernova Hitachi submitted a GDA entry application for its BWRX-300 SMR to the UK Department for Business, Energy and Industrial Strategy in December 2022. The BWRX-300 is a 300 MWe water-cooled, natural circulation SMR with passive safety systems that leverages the design and licensing basis of GEH’s ESBWR boiling water reactor.
Step 1 of the GDA of the BWRX-300 began in January 2024 and focused on agreeing the scope and schedule for Step 2. Step 1 was completed on 12 December 2024, when it then entered Step 2, which focused on evaluating the fundamental adequacy of the design and its safety, security, safeguards and environmental protection documentation. The regulators have now completed Step 2 of the GDA and issued their Step 2 statements and assessment reports on the GE Vernova Hitachi design.
There are currently no plans to deploy the GE Vernova Hitachi BWRX-300 design in Great Britain, and no sites have been identified for its deployment. Should an organisation decide to progress plans to deploy the BWRX-300 design, the regulators would need to undertake a further period of detailed design assessment before safety-significant construction could begin and environmental permits could be issued. This assessment could be conducted on a generic basis with GE Vernova Hitachi, should the company choose to return to the GDA process to complete Step 3. Alternatively, it could be undertaken with a licensee or constructor as part of a site-specific development.
“GE Vernova Hitachi opted for a shorter two-step GDA, making it the first requesting party to take advantage of the flexibility we introduced in our modernised GDA process,” said Rob Exley, ONR’s Head of the BWRX-300 GDA. “This means it is the quickest GDA engagement completed to date, facilitated by GE Vernova Hitachi’s responsiveness, the quality and maturity of its submissions, learning from previous GDAs, and our active collaboration with regulatory colleagues in the US and Canada who have been evaluating the BWRX-300 in parallel to our assessment.”
Saffron Price-Finnerty, the Environment Agency’s New Reactors Programme Manager, added: “The accelerated pace of this first two-Step GDA was enabled by the delivery of a complete set of documentation by GE Vernova Hitachi at the start of Step 2. This helped our assessment team to plan their work effectively and efficiently. Their assessments were targeted and proportionate in ensuring that there were no fundamental shortfalls in environmental protection. It has been a considerable effort from both the Requesting Party and regulators, resulting in a quality outcome in such a short timeframe. As the environmental regulator of nuclear sites and radioactive substances in England, the Environment Agency ensures that nuclear companies and the sites they operate meet high standards of environmental protection throughout the stages of design, construction, operation and decommissioning.”
“Throughout Step 2 we have worked closely with the Environment Agency and Office for Nuclear Regulation towards the fundamental assessment of the GE Vernova Hitachi SMR, resulting in the successful delivery of this first two-step GDA,” said Paul Gibson, Natural Resources Wales Nuclear Team Leader.
GDAs have previously been completed for the EDF/Areva UK EPR, the Westinghouse AP1000, the Hitachi-GE UK ABWR and the CGN/EDF/GNI UK HPR1000 designs. A GDA Step 3 assessment is currently ongoing for Rolls-Royce SMR Limited’s small modular reactor design. In August 2024 a Step 2 assessment began for Holtec International’s SMR-300. In August 2024, Westinghouse’s AP300 was accepted for a GDA review. Last month, TerraPower submitted its Natrium sodium-cooled fast reactor and energy storage system into the GDA process in the company’s first regulatory step to deploying the technology in an international market.
