Improving design assessment for new nuclear power stations

Summary

We are improving how we assess the design of new nuclear power stations to support faster deployment of new nuclear in Great Britain.

This page explains how the regulators are streamlining design assessment processes, introducing greater flexibility in routes to licensing and permitting, and working towards completing reactor design assessments within two years - while maintaining our high standards for safety, security, safeguards and environmental protection.

Direction

The UK government has given clear direction through the Prime Minister’s strategic steer and its acceptance of the principles of the Nuclear Regulatory Review to accelerate new nuclear deployment. 

In response to this steer, and based on our own learning from recent Early Engagement (EE) activities and Generic Design Assessments (GDAs), the nuclear regulators (the Office for Nuclear Regulation (ONR), the Environment Agency, and Natural Resources Wales (NRW) are:

• setting out how our current arrangements support new nuclear facilities from early design through to construction highlighting the flexible options available in regulatory assessment of new nuclear reactors
• describing the approaches we are implementing now to improve these processes to support delivery of reactor design assessment within 2 years
• introducing our plans for a comprehensive and integrated update of our guidance by Spring 2027

None of these changes will affect our standards for safety, security, safeguards, and environmental protection (SSSE).

We have also developed a new joint policy on leveraging international judgements and assessments following the announcements under the UK-US Technology Prosperity Deal and  Atlantic Partnership for Advanced Nuclear Energy.

Regulatory control of new nuclear facilities

Building, operating, and decommissioning a nuclear reactor is complex and involves significant risk. Robust engineering, effective management, and proportionate regulatory oversight are essential to ensure SSSE.

In Great Britain, nuclear safety is assured through a statutory licensing system, where a company must obtain a nuclear site licence from ONR before installing or operating a nuclear reactor. In England and Wales, environmental protection is assured through environmental permits, which must be obtained from the relevant environmental regulator.

To get a licence or permit an applicant needs to demonstrate that it has organisational capability to conduct licensable and permitted activities on an identified site that is deemed suitable in compliance with the 36 conditions attached to a nuclear site licence as well as environmental permit conditions. The nuclear regulators work together to ensure that SSSE are appropriately balanced. Once a licence and permits are granted, the nuclear regulators regulate through these conditions.

Under the site licence ONR may apply legally binding hold points to apply regulatory control over safety significant activities. ONR implements hold points where there are significant changes in risk to ensure these are being controlled appropriately, for example the start of nuclear safety related construction. After a hold point is released ONR monitors performance through inspections, subsequent assessments, and takes enforcement as necessary if shortfalls are identified.

Similarly, the environmental regulators will assess permit compliance through regulatory interactions, inspections, and assessments. Permits can specify pre-operational conditions and requirements for further information, known as information or improvement requirements. In this way, environmental protection matters can be considered before the detailed design is finalised and throughout procurement, construction and commissioning. Where shortfalls are identified, enforcement action will be taken as necessary.

Prior to gaining a site licence or environmental permits, the regulators can provide advice through our voluntary EE and GDA processes. Although these processes are not mandatory, we apply consistent assessment standards proportionately to the design maturity and stability. This allows us to assess aspects of the design and SSSE case earlier, increasing confidence they can meet legal requirements, accelerating the future statutory licensing, permitting, and permissioning activities.

Approaches being implemented

Through this position statement, the regulators are improving our design assessment processes. This is intended to enable flexibility and shorten the duration of regulatory design assessment while maintaining consistent standards for SSSE. The measures we are implementing are described below.

Step 1 of GDA (Initiation) will take place as a distinct activity, with flexibility as to when this is conducted. This GDA preparation activity does not include design assessment, and the time required to complete it may depend on factors outside of the regulators’ control such as the Requesting Party’s (RP’s) organisational readiness and familiarity with UK regulatory expectations. GDA Initiation will therefore not form part of the regulators’ target two year design assessment period. Undertaking GDA Initiation as a distinct activity reinforces the opportunity for GDA preparation activities to be undertaken alongside early engagement activities, with potential for efficiencies, avoidance of duplication and for these to inform each other. For example, we could consider requests to undertake process and technical engagements and preliminary design reviews, as described in our early engagement process guidance, in parallel with GDA preparation before GDA Step 2 (Fundamental Assessment) or GDA Step 3 (Detailed Assessment) activities commence.

Similarly, following completion of a Step 2 GDA (Fundamental Assessment) the RP may continue to develop its SSSE case and receive advice in preparation for the readiness review to commence a Step 3 GDA (Detailed Assessment) or licensing or permitting applications. This advice could be received through additional early engagement or site-specific pre-licensing and pre-permit application activities.

As a key enabler to completing design assessment within two years, experience shows that regulatory assessment is most efficient when the design is stable and a full suite of documentation is submitted at the start of the assessment process. To support this, the entry criteria for commencing a Step 2 GDA (Fundamental Assessment) or Step 3 GDA (Detailed Assessment) are being strengthened, and we will review these submissions as part of the readiness review to confirm they will enable a meaningful regulatory assessment. Significant changes to the design or SSSE case during the regulatory assessment process, delays to delivery of documentation or poor quality documentation will result in longer timescales.

Licensing and permitting guidance has historically assumed completion of a Step 3 GDA (Detailed Assessment) before site licence and permit applications, but in practice some organisations are not undertaking any GDA assessments before applying for a nuclear site licence and operational permits. We recognise that the optimal route to licensing and permitting may vary between projects, and the flexibility in our processes is intended to enable this. For nuclear site licensing ONR must be confident that the design is suitable for deployment, even if it is not fully detailed. As this assurance broadly aligns with the expectations for a Step 2 GDA (Fundamental Assessment), these expectations are now being aligned into a common assessment process that will apply to GDA or to site-specific design being assessed as part of a site licence application. Information equivalent to a Step 3 GDA (Detailed Assessment) is required to support release of the ONR nuclear safety related construction hold point and currently for operational environmental permit applications.

Regardless of the route taken, the same ultimate expectations for demonstration of safety, security, safeguards and environmental protection apply before permission to construct or operate a new nuclear power station will be granted. We encourage regulatory engagement as early as possible to take full advantage of the benefits from early advice and guidance.

Planned future updates

Developing a reactor assessment framework

We will develop a single integrated regulatory framework and guidance to replace the existing ONR, Environment Agency and NRW guidance for EE and GDA by Spring 2027. This update will include the provision for a RP to transition to the updated guidance.

This new framework will build on the experience we have gained from EE, GDA, licensing, permitting and permissioning new reactors and will remove duplication, streamlining and simplifying the regulatory processes for reactor designs to undergo regulatory assessment up to the start of construction. We intend to implement arrangements to enable the issue of a single regulatory output describing our joint decision on design acceptability.

The framework will not change the regulatory standards for SSSE. Instead, it will provide clarity in voluntary and statutory pathways, with the main changes being the structure, naming, and transition arrangements between stages. It also aims to improve how judgements and evidence generated at one stage can be re-used for future assessments.

Improving public and stakeholder engagement

Public and stakeholder engagement has been central to GDA since the process was first developed. Using learning from GDAs the regulators are currently reviewing our public and stakeholder engagement approaches. This is with a view to identifying opportunities for improving how we interact with the public and other stakeholders, incorporating flexibility and seeking efficiencies in alignment with other regulatory processes.