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Rolls-Royce SMR design progresses to next step of safety assessment

07 Apr 2023 4 minute read
Image Rolls-Royce

The Office for Nuclear Regulation (ONR), the Environment Agency, and Natural Resources Wales (NRW) have announced that they are moving on to the next phase of their assessment of Rolls-Royce’s MW Small Modular Reactor (SMR) design.

The SMR is a small, modular nuclear reactor that is designed to be cheaper and easier to build than traditional nuclear power plants. Rolls-Royce says that its SMRs will be able to generate 470 megawatts of electricity, enough to power around 150,000 homes.

Last November Rolls-Royce announced Wylfa and Trawsfynydd were on a shortlist of potential locations to site the new ‘small’ nuclear reactors.

Deeside was also shortlisted, along with two sites in England, as the potential location for the first factory to supply parts for its proposed fleet of mini-nuclear reactors.

Rolls-Royce’s SMR is going through the process, known as Generic Design Assessment (GDA), which allows the regulators to begin assessing the safety, security, safeguards, and environmental aspects of new reactor designs before site-specific proposals are brought forward.

The first phase of the GDA began in April 2022 and has now been successfully completed following preparatory work by the company and the regulators. Step two, which commenced on Monday, is expected to last for 16 months.

The first phase of the process involved agreeing the scope of the assessment, which was based on information supplied by the manufacturer to ONR, the Environment Agency, and NRW.

This information was used by the regulators to undertake a meaningful assessment of the design.

During the past year, Rolls-Royce SMR Ltd has completed all the requirements for Step 1 from the regulators’ guidance. They have also made good progress in developing their organisation and arrangements to support GDA.


Rolls-Royce SMR has also launched a comments process on its new website.

This process 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 the responses to these issues, will be used to help inform the regulators’ assessments throughout the rest of the GDA process.

Rob Exley, ONR’s Head of Generic Design Assessment, said: “The purpose of GDA is to determine whether the design meets our robust safety, security, safeguards, and environmental protection standards in Great Britain.

“We are working together with the Environment Agency and NRW to ensure Rolls-Royce SMR Ltd understand and meet our regulatory expectations for its proposed reactor design.

“As nuclear regulators, we recognise that we are acting in the interests of the public and, as such, this period of scrutiny will be open, transparent, and provide regular opportunities for meaningful engagement with interested parties throughout the GDA process.

“ONR is satisfied that Rolls-Royce SMR Ltd has adequate arrangements to support GDA. We have agreed an appropriate scope for GDA, for which the company has provided an appropriate submission schedule and a resourced organisation to deliver it.

“As regulators, we can now begin our technical assessment phase.”

A spokesperson for Natural Resources Wales said: “We are pleased that the GDA process for the Rolls-Royce SMR is progressing well. We will continue to work with the regulators and Rolls-Royce SMR to ensure that the design meets our high environmental standards.”


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

At the end of the process a Design Acceptance Confirmation (DAC) or Statement of Design Acceptability (SoDA), from ONR and the environmental regulators respectively, will only be issued at if the design meets the safety, security, safeguards, environmental protection and waste management standards set out in the 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 for the construction of a power station based on the Rolls-Royce SMR design at a particular site.

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Mab Meirion
Mab Meirion
1 year ago

Are these reactors compatible with an independent Cymru?

max wallis
max wallis
1 year ago

Both planning and waste disposal are devolved matters. Can wales require the exemption from energy efficiency – and from beneficial use of the waste heat – is ended?
As for independence, the use of nuclear power plants in the Ukraine as strong-bases to against bombing and shelling, and for attacking the locality. As it can be seized by terrorist or invaders, a nuclear plant forms a point of vulnerability. Not good !

Peter Cuthbert
Peter Cuthbert
1 year ago
Reply to  max wallis

Some good points. Don’t forget that the Consultation (See link in the text) is still open and anybody can comment. I have done so and pointed out that the erection of such plant on ‘remote’ sites rather undermines their USP that these are such safe reactors. There is also the issue that Wales does not need the power they will produce and so will be forced to suffer the transmission lines back to England where it is needed. Finally, the Company ought to think again as those of us who live in Cymru and are not Tories see this aa… Read more »

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