UK nuclear regulators have determined GE Vernova Hitachi’s BWRX-300 small modular reactor design meets fundamental safety and environmental standards, clearing it for potential construction after completing Step Two of the Generic Design Assessment.
Regulators Approve SMR Design After Detailed Review
The Office for Nuclear Regulation, the Environment Agency, and Natural Resources Wales said the design poses no fundamental safety, security or environmental protection issues that would prevent its future use in Great Britain. The decision follows an in-depth review under the UK’s modernized GDA framework for new nuclear technologies.
The GDA is a voluntary assessment that evaluates reactor designs before site-specific approvals. Regulators said Hitachi’s BWRX-300 submissions were complete and aligned with parallel reviews underway in the United States and Canada.
“GE Vernova Hitachi opted for a shorter two-step GDA, making it the first requesting party to take advantage of the flexibility we introduced,” said Rob Exley, ONR head of Hitachi’s BWRX-300 assessment. “This is the quickest GDA engagement completed to date, driven by the company’s responsiveness and the maturity of its design documentation.”
Review Marks Milestone for Advanced Nuclear Technology
Hitachi’s BWRX-300 is a 300-megawatt electric, water-cooled modular reactor based on GEH’s ESBWR boiling water reactor. The UK opened the GDA process to advanced nuclear technologies in 2021. GE Vernova Hitachi applied for entry in December 2022, and regulators began Step one in January 2024, completing it last December.
Step two focused on evaluating the design’s fundamental adequacy across safety, security, safeguards, and environmental protection. With the process complete, regulators issued assessment reports confirming compliance with core requirements.
Saffron Price-Finnerty, the Environment Agency’s New Reactors Programme Manager, said the accelerated review reflected efficient planning and a full document set from the company at the start of Step two. “Our assessments were targeted and proportionate in ensuring there were no fundamental shortfalls in environmental protection,” she said. “It has been a considerable effort from both the Requesting Party and regulators.”
Natural Resources Wales also praised the coordinated regulatory approach. “Throughout Step two, we have worked closely with our partners toward the fundamental assessment of the GE Vernova Hitachi SMR,” said Paul Gibson, the agency’s nuclear team leader.
Next Steps Depend on Industry Interest and Site Selection
Regulators emphasized that no deployment plans are in place, and no UK sites have been identified for a BWRX-300. Any organization seeking to build the reactor would require a further detailed assessment before construction or environmental permitting could begin.
That next phase could proceed either as a generic Step three review with GE Vernova Hitachi or as a site-specific assessment with a licensee or constructor. Both paths would involve additional regulatory scrutiny on safety-significant systems.
Several other reactor designs are currently in the UK’s GDA pipeline, including Rolls-Royce SMR Limited’s modular reactor, Holtec International’s SMR-300 and Westinghouse’s AP300, which entered review last year. TerraPower’s Natrium fast reactor and energy-storage system recently submitted its GDA application, marking the company’s first step toward an international deployment.
Completed GDAs include the EDF/Areva UK EPR, Westinghouse AP1000, Hitachi-GE UK ABWR, and the CGN/EDF/GNI UK HPR1000 designs.
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