The Office for Nuclear Regulation, along with the Environment Agency and Natural Resources Wales (NRW), has started a three step Generic Design Assessment (GDA) for TerraPower LLC’s Natrium reactor design.
The Department for Energy Security and Net Zero made the request to the regulators following its readiness review of the TerraPower entry application.
This review concluded that the design is ready to enter the GDA process and the regulators have now finalised arrangements with TerraPower, enabling the GDA to commence.
During the coming months, the ONR team will engage with the Requesting Party as well as the Environment Agency and NRW, to prepare and agree interface arrangements, undertake reactor familiarisation activities, and develop and define the GDA scope, project delivery strategy and assessment plans needed to guide future formal assessment activities.
GDA is a voluntary process that enables the regulators to assess the safety, security, safeguards and environmental implications of new nuclear power station designs before site-specific decisions are made.
By undertaking this assessment at the design stage, regulators can identify and enable the Requesting Party to address potential issues early, helping to support the safe and efficient deployment of new nuclear technologies in Great Britain. We also ensure alignment with nuclear security requirements and UK safeguards obligations.
Diego Fernandez Lisbona, ONR’s Head of Regulation for the TerraPower Natrium GDA and Advanced Nuclear Technologies, said:
“Confirming arrangements is an important enabling step for ONR to engage with and assess TerraPower’s Natrium design.
“Positive discussions with TerraPower in 2025, through our framework for Early Engagement, have provided early design familiarity and a head start for team mobilisation and development of our project delivery strategy.
“Our focus is on agile and timely delivery of a robust, risk-informed and proportionate assessment of the design’s safety, security and safeguards aspects, to ensure it meets UK regulatory requirements and expectations."
ONR will continue to work closely with the other regulators and TerraPower as the GDA progresses, and will look to explore opportunities to maximise the value of international regulatory collaboration and identify efficiencies in processes, maintaining its role as an independent regulator focused on protecting society by securing safe nuclear operations.