The Office for Nuclear Regulation (ONR) has set out a significant programme of reform designed to speed up nuclear project delivery across the UK, in response to a letter from the Chancellor on the implementation of the Nuclear Regulatory Review.
In his reply, ONR's Chief Executive and Chief Nuclear Inspector, Mike Finnerty, describes how the regulator is transforming its approach to keep pace with a rapidly growing nuclear sector, while continuing to maintain strong safety, security and safeguards standards, protecting people and the public.
Central to this transformation is ONR Together, the regulator's new rolling strategy for becoming a more modern, agile and productive organisation.
ONR has taken concrete steps to turn this ambition into practice, including the creation of a Lead Nuclear Regulator Group to improve coordination between regulators and resolve issues earlier in major programmes, and an Industry CEO Forum bringing together senior leaders from across government, industry and regulation to tackle the behaviours that contribute to unnecessary delay.
Revised safety case guidance has been published to help industry produce clearer and more proportionate safety arguments without compromising standards, and a review of regulatory processes is identifying where decision making can be made more focused and streamlined.
The regulator is also modernising how it assesses new reactor designs, adopting a more flexible approach within Generic Design Assessment programmes and working towards fleet-based regulatory models for a range of reactor technologies.
Alongside this, ONR continues to prioritise high-hazard risk reduction at Sellafield and is investing in the data, digital tools and workforce capability needed to regulate an increasingly complex sector.
Looking ahead, ONR is supporting government proposals for a Commission for Nuclear Regulation and reforms to its charging model, while expanding international collaboration to enable mutual learning and the efficient deployment of proven nuclear technologies.
Mike Finnerty, ONR's Chief Executive and Chief Nuclear Inspector, said: "Nuclear has a critical role to play in the UK's energy future, and industry, government and regulators can work together with collaboration and confidence.
"The government has set its strategic direction for a growing nuclear sector, and so it's our job to regulate this industry so that it remains safe and new projects can be deployed without unnecessary delay.
"Our continuing commitment to risk-informed, outcome-focused regulation means we can be both more agile in enabling nuclear delivery and unwavering on safety, focusing our effort where it delivers the greatest benefit."
Letter to Rt. Hon John Healey MP, Chancellor of the Exchequer
10 September 2026
Dear Chancellor
Implementing the Nuclear Regulatory Review 2025
Thank you for the letter of 13 March 2026 regarding implementation of the Nuclear Regulatory Review 2025.
The expansion of the UK's nuclear energy and defence programmes presents a significant national opportunity. More effective nuclear regulation supports reindustrialisation by providing confidence, certainty and pace for investment in new nuclear - enabling innovation, high-value jobs and resilient UK supply chains while maintaining the highest standards of safety, security and safeguards. To realise its potential, government, regulators and industry must work with greater pace, clarity and alignment. For ONR, this means being ready to regulate a sector growing rapidly in scale and complexity while continuing to enable safe, secure and efficient delivery through timely and proportionate regulation.
Through our new strategy, ONR Together, we are undertaking a significant programme of change to ensure our approach remains effective and fit for the future. We are strengthening risk-informed decision making, simplifying regulatory expectations and focusing effort where it delivers the greatest value.
I fully support the Review's conclusions that radical reforms are needed. I have instructed my teams to focus on a more outcomes-based regulatory system, without compromising our role to protect people and the environment. The radical reforms we are implementing will maintain robust oversight where hazards are greatest, but will also reduce unnecessary bureaucracy, strengthen professional judgement and provide greater regulatory certainty to enable industry to accelerate its programmes.
Our response focuses on three priorities:
Creating a More Integrated Nuclear Regulatory System
To improve coordination across the nuclear landscape, I have established the Lead Nuclear Regulator Group (LNRG), bringing key regulators together to improve collaboration, reduce duplication and resolve issues earlier across major programmes. The LNRG is an important initial step towards a more integrated, outcome-focused regulatory system that in itself will reduce duplication and speed up decision-making, but will also provide a foundation for considering future arrangements that bring nuclear regulation together within a clearer framework.
We believe the Government’s consideration of a Commission for Nuclear Regulation will improve coherence, transparency, accountability and pace of delivery across the sector while maintaining standards and regulatory independence. Building on the integration of civil and defence nuclear regulation within ONR, this model could reduce complexity for investors and operators while strengthening system-wide effectiveness.
Drawing on international experience, I also believe that meaningful early community engagement should be a central feature of any future regulatory model. Giving communities a stronger voice can strengthen trust, enhance public confidence and maximise the long-term benefits of nuclear investment. Without this feature, the UK may face more protracted consultation processes, delays in decision-making, and increased schedule risk for major projects.
Stronger Leadership and Culture
Mindful of the key point that delay is not a neutral outcome; it carries its own risks, our new strategy ONR Together sets out our vision to become a more modern, agile and productive regulator, providing the clarity, confidence, proportionality and pace needed to support investment, and to enable safe and timely delivery across the sector.
We have set out a series of culture shifts that I believe are required across ONR to create an organisation with the right attributes to drive effective delivery. Implementation of these culture shifts is a key priority of our executive leadership team.
Additionally, and recognising that culture is a whole-system issue, I have established an Industry CEO Forum to enable alignment of industry culture to strengthen leadership, promote openness and learning, challenge behaviours that create unnecessary delay and foster collective accountability to expedite delivery of the UK's nuclear ambitions.
Smarter, Digital and Risk-Informed Regulation
We are driving a fundamental transformation of ONR's regulatory framework and delivery model to enable faster, more effective and more proportionate regulation. Through modernised Safety Assessment Principles (SAPs), streamlined safety case guidance, enhanced use of data and digital technologies, and more consistent decision-making, we are creating a regulatory system that is clearer, more predictable and focused on the issues that matter most.
We are also championing a step change in safety case practice, moving away from unnecessarily complex and voluminous documentation towards concise, evidence based safety arguments focused on significant risks and effective controls. By combining risk-informed decision-making with digital and data-enabled regulation, we will improve assessment efficiency, identify emerging risks earlier, target regulatory effort where it adds greatest value, and reduce unnecessary burden on dutyholders.
Together, these reforms represent the most significant programme of regulatory modernisation undertaken by ONR. They will create a regulatory environment that is clearer and more predictable while maintaining standards of nuclear safety, security and safeguards that underpin public trust.
None of this changes ONR's fundamental purpose: to protect people and society. Our ambition is not to lower standards, but to apply them more intelligently, proportionately and consistently, with regulatory effort focused where it delivers the greatest benefit.
The appendix provides examples of the reforms at the heart of ONR's transformation and demonstrates how we are responding decisively to the five questions raised in the letter of 13 March.
ONR is not seeking incremental improvement. We are transforming how regulation is delivered and how change is enabled across the nuclear sector. We will move beyond measuring success through activity and process, focusing instead on outcomes, impact and the value we create. Success will be reflected in the confidence our decisions inspire, the improvements our regulation enables and the lasting change we help deliver.
Yours sincerely,
Michael Finnerty
ONR Chief Executive and Chief Nuclear Inspector
Appendix
1. How ONR plans to improve the timely and cost-effective delivery of the Government's nuclear programme while maintaining safe outcomes
We are doing this through a combination of stronger regulatory coordination, smarter regulation and earlier engagement with dutyholders and developers.
We have established the Lead Nuclear Regulator Group (LNRG) to strengthen coordination between regulators, reduce duplication, and enable issues to be identified and resolved earlier across major programmes. Work is underway to implement Lead Regulator Models (LRMs) for Generic Design Assessment (GDA) and Low Level Waste Repository (LLWR) programmes, while early engagement with a major defence project is helping to test the model and demonstrate its potential benefits.
We are also contributing to the Government's consideration of a Commission for Nuclear Regulation, which could further simplify the regulatory landscape, improve coherence and accountability, and maintain regulatory independence. As experience and evidence from the LNRG continue to develop, we have advised Government that flexibility within the draft Bill is essential to accommodate emerging lessons and other insights before the Commission's final model and scope are determined to support the delivery of the UK's nuclear ambitions.
We recognise that meaningful early engagement with the public is essential to building trust, understanding and confidence in nuclear developments. By encouraging transparent dialogue early in the process, listening to community perspectives and addressing concerns proactively, the Commission would help ensure better-informed decision-making, strengthen public trust and confidence, and create the conditions for the timely and successful delivery of the UK's nuclear programmes.
Alongside this, we are modernising our regulatory approach through greater use of risk-informed decision making, increased proportionality and clearer expectations, including recognising proven technologies and operating experience where appropriate. This includes adopting a more agile, collaborative and transparent approach to GDAs, maintaining momentum on high-hazard risk reduction at Sellafield and supporting new fuel manufacturing capability, while focusing regulatory effort on activities that deliver demonstrable safety improvements.
We are also driving greater alignment across government, industry and international partners to support fleet-based approaches for European Pressurised Reactors and Small Modular Reactors, to strengthen the nuclear supply chain, expand international collaboration and enable the safe, timely delivery of critical civil and defence nuclear programmes. Enhanced use of data and digital tools will further improve planning, prioritisation and oversight, while maintaining robust standards and providing greater certainty for investors and developers.
2. What changes ONR is making to improve pace, proportionality and coordination
ONR is undertaking a significant programme of regulatory change to improve pace, proportionality and coordination while ensuring regulatory attention remains focused on the areas of greatest risk.
Examples include:
- Revising Safety Assessment Principles (SAPs) to strengthen risk-informed and judgement-based regulation.
- Implementing revised safety case guidance that supports clearer, more proportionate and evidence-based safety arguments.
- Simplifying supporting guidance and streamlining regulatory processes where they add limited value.
- Strengthening coordination through the LNRG and exploring opportunities to simplify regulatory interfaces.
- Expanding the use of digital tools, data analytics and management information to support faster, more consistent decision making.
These changes are underpinned by a broader cultural shift that encourages professional judgement, accountability and a stronger focus on regulatory outcomes rather than process. The objective is a regulatory system that is easier for industry to navigate while maintaining confidence in safety outcomes.
3. What measures ONR will take to address the cultural issues identified in the Taskforce report
The Review rightly identifies culture and leadership as critical enablers of successful delivery. Through our ONR Together strategy, we are embedding changes designed to strengthen accountability, professional judgement and organisational effectiveness.
As a key architect of the G6 model that delivered significant change at Sellafield, I recognise both the opportunities and challenges presented by the nuclear renaissance. In response, I have carefully selected and strengthened the executive leadership of ONR, bringing together leaders with the mindset, capability and determination required to deliver meaningful change. Together, we will drive transformational change across ONR, ensuring the organisation is equipped to meet future regulatory demands with pace, agility and impact.
We are reinforcing the expectation that delay is not a neutral outcome and that regulatory decisions should be timely, evidence-based and focused on delivering outcomes. We are supporting this through leadership development, workforce capability programmes and improvements to decision-making processes.
Recognising that culture is a whole-system issue, I have established an Industry CEO Forum that brings together senior leaders from industry and the regulatory community. The forum provides a platform for leaders to collectively shape the cultural environment needed to deliver the UK's nuclear ambitions safely, securely and efficiently.
The forum will also challenge behaviours, incentives and ways of working that create unnecessary delay or hinder progress, encouraging a more collaborative and outcomes-focused approach to delivery. By strengthening collective accountability, sharing lessons and addressing systemic barriers, leaders can improve decision making, build organisational resilience and support the timely delivery of nuclear projects while maintaining the highest standards of safety, security and public trust.
These cultural reforms complement our wider work to improve regulatory coordination, simplify expectations and support a modern, delivery-focused nuclear sector.
4. How contractual arrangements could be modified to better support timely project delivery
While ONR does not determine dutyholder contractual arrangements, we can influence behaviours across the sector and help create conditions that support more effective delivery.
Experience suggests that some contractual models encourage increasing volumes of documentation and assurance activity without a corresponding improvement in safety outcomes. Through our programme of smarter regulation, we are promoting clearer, evidence-based safety cases that focus on understanding risks, demonstrating effective controls and enabling informed decision making.
Combined with stronger leadership across the sector and more integrated regulatory arrangements, these approaches can help reduce rework, improve decision quality and support more efficient programme delivery.
5. What savings are expected in terms of time and cost
We commissioned an independent initial economic assessment to evaluate the potential savings arising from the recommendations for which ONR has a lead role in delivery.
Our recent experience demonstrates the benefits that can be achieved through international collaboration and improvements to regulatory processes. For example, the most recently completed two-step GDAs for the GE Vernova Hitachi BWRX-300 and Holtec SMR-300 realised substantial efficiencies compared with equivalent stages of previous GDAs. Resource deployment was reduced by more than 35%, while maintaining the same scope and level of regulatory rigour. As a result, both GDAs were delivered several million pounds under budget.
The assessment also indicates that our work to clarify and embed simpler, more proportionate expectations for the development and assessment of safety cases, together with the review and revision of regulatory guidance, could deliver significant longer-term benefits. By eliminating duplication, reducing unnecessary analysis and restoring safety cases to practical documents that directly support dutyholders' operations, these reforms will help focus resources on the most significant risks. They should also support faster and more efficient project delivery across the nuclear sector.
In addition, the independent economic assessment identifies clear potential for both the lead regulator model and increased international collaboration to generate material annual savings for industry. These benefits are expected to arise through shorter and more predictable assessment timelines, lower regulatory charges, and reduced costs for requesting parties. The assessment suggests that the greatest savings are likely to come from improved efficiency, greater predictability, and a reduced regulatory burden across the sector, with reductions in regulatory charges representing a smaller proportion of the overall benefits.