The Office for Nuclear Regulation (ONR), the Environment Agency, and Natural Resources Wales (NRW) have announced their advancement to the next phase of evaluating Rolls-Royce SMR Ltd's 470 MWe Small Modular Reactor (SMR) design.

The Generic Design Assessment (GDA) process allows the regulators to begin assessing the safety, security, safeguards and environmental aspects of new reactor designs before site-specific proposals are brought forward.

GDA is an enabling and efficient way of helping to ensure that new nuclear power stations will meet high standards of safety, security, environmental protection and waste management while providing the Requesting Party with the means to reduce overall project risks and gain increasing levels of regulatory confidence in their design.

The Rolls-Royce SMR GDA began in April 2022 with a year-long initiation step, followed by Step 2, a 16-month assessment looking at the fundamentals of the design.

Step 2 has now been successfully completed following significant work by Rolls-Royce SMR Ltd and the regulators, leading to the granting, for the first time since the modernised GDA process was launched, of Step 2 GDA statements.

Today also marks the start of Step 3 for the Rolls-Royce SMR Ltd GDA.

Step 2 is the first substantive technical assessment step of GDA, building upon the work to agree the scope and project arrangements undertaken during Step 1.


The focus of the assessment was towards the fundamental adequacy of the design and safety, security, safeguards and environment cases, and the suitability of the methodologies, approaches, codes, standards and philosophies which form the building blocks for the generic design.

During the Step 2 process, Rolls-Royce SMR Ld has completed all the requirements from the regulators' guidance.

Rob Exley, ONR's Head of Generic Design Assessment, said: "The Rolls-Royce SMR GDA is one of firsts. We are the first regulators to assess this reactor design, determining whether it meets our robust safety, security, safeguards and environmental protection standards in Great Britain. It is also the first time we have followed the modernised GDA process, looking at an SMR design.

"ONR is satisfied that Rolls-Royce SMR Ltd are progressing and as regulators, we can now continue into Step 3 assessing in more detail the evidence that supports the claims made about the design in the Step 2 submissions.

"We will continue working together with the Environment Agency and Natural Resources Wales to ensure Rolls-Royce SMR Ltd understands and meets our regulatory expectations for its proposed reactor design.

"Based on our work during Step 1 and 2, the generic Rolls-Royce SMR design can proceed to Step 3 of the GDA.”

Rolls-Royce SMR Ltd’s comments process continues through Step 3. It enables anyone to submit comments and questions about the reactor design to the company for its response.

Relevant issues raised during the comments process, and Rolls-Royce SMR Ltd’s responses to these issues, will continue to be used to help inform the regulators’ assessments throughout the rest of the GDA process.

The GDA process focuses on the design of a generic nuclear power station and is not site-specific.

The process is systematic and contains a number of steps, with the assessment getting increasingly detailed as the process develops.

A Design Acceptance Confirmation (DAC) or Statement of Design Acceptability (SoDA), from ONR and the environmental regulators respectively, will only be issued at the end of Step 3 of the GDA if the design meets the high safety, security, safeguards, environmental protection and waste management standards expected by our regulatory frameworks.

These regulatory judgements do not guarantee the granting of a site licence or subsequent permissions issued under the conditions of a site licence or environmental permits for the construction of a power station based on the Rolls-Royce SMR design at a particular site in Great Britain.