Office for Nuclear Regulation

What is the Office for Nuclear Regulation?

The Office for Nuclear Regulation (ONR) is the UK’s independent regulator of the civil nuclear industry. It is a public corporation of the Department for Business and Trade. ²⁹ Office for Nuclear Regulation, ‘Office for Nuclear Regulation’, GOV.UK, no date, accessed 16 January 2026, www.gov.uk/government/organisations/office-for-nuclear-regulation  It employs over 600 staff and is headquartered in Bootle. ³⁰ Nuclear Graduates, ‘Office for Nuclear Regulation’, Nuclear Graduates, no date, accessed 15 January 2026, https://nucleargraduates.com/sponsors/office-for-nuclear-regulation

What does the ONR do?

The ONR’s mission is to protect society by ensuring the safety of all nuclear operations. It achieves this through its five statutory purposes: ³¹ Office for Nuclear Regulation, ‘Our role’, GOV.UK, no date, accessed 16 January 2026, www.onr.org.uk/about-us/our-role

1. nuclear safety (protecting people and the environment from nuclear-associated risks)
2. health and safety of nuclear sites
3. nuclear security (protecting against threats such as terrorism or sabotage targeting nuclear infrastructure)
4. nuclear safeguards (ensuring that material from civil nuclear programmes is used for peaceful purposes only)
5. safe transport of nuclear waste and materials.

The ONR’s remit extends to the 36 licenced nuclear sites in Great Britain (there are none in Northern Ireland). These sites include operational, defueling and decommissioned power stations; new and proposed reactors; manufacturing and decommissioning facilities; and defence sites.

While the ONR does regulate activities at Atomic Weapons Establishment (AWE) sites which provide and maintain nuclear warheads, it does not regulate the design of warheads themselves. Responsibility for this lies with the Defence Nuclear Safety Regulator (DNSR), a separate body within the Defence Safety Authority, part of the Ministry of Defence. ³² Office for Nuclear Regulation, ‘Weapons’, ONR, no date, accessed 16 January 2026, www.onr.org.uk/our-work/what-we-regulate/defence/weapons  

How does the ONR regulate?

The ONR regulates the nuclear industry through a combination of site licencing, inspection, formal enforcement and persuasive influence. ⁴¹ Office for Nuclear Regulation, ‘How we regulate’, ONR, no date, accessed 16 January 2026, www.onr.org.uk/our-work/how-we-regulate  Under the Nuclear Installations Act 1968, the ONR issues licences to corporate bodies to use sites for specified purposes. The licence, which is a legally binding document issued for the duration of a nuclear installation’s life cycle, sets out site-specific conditions necessary for its safe operation. Each licence is contingent on 36 conditions, which establish the safety responsibilities of the licensee surrounding construction, procurement, operation etc. ⁴² Office for Nuclear Regulation, Licence condition handbook, ONR, February 2017, www.onr.org.uk/media/gixbe2br/licence-condition-handbook.pdf

Before a licence is issued, the ONR assesses licensees’ safety cases to determine whether risks are understood and controlled. Then, once a licence has been granted, the ONR conducts regular compliance inspections, and can take enforcement action if conditions are not met. Enforcement ranges from providing advice through to prosecution. ⁴³ Office for Nuclear Regulation, Enforcement Policy Statement, ONR, March 2024, www.onr.org.uk/our-work/how-we-regulate/enforcement  The ONR also uses its influence to bring about improvements in areas which are “difficult to regulate”, such as health and safety culture and leadership. ⁴⁴ Office for Nuclear Regulation, ‘How we regulate’, op. cit.

What are the future opportunities for the ONR?

The UK’s nuclear regulatory landscape came under scrutiny in the Nuclear Regulatory Review 2025, led by economist John Fingleton. The review found that the nuclear regulatory landscape in the UK is overly complex and risk averse, which has led to the UK becoming “the most expensive place in the world to build nuclear projects”. ⁴⁵ Fingleton J, Nuclear Regulatory Review 2025, GOV.UK, 24 November 2025, www.gov.uk/government/publications/nuclear-regulatory-taskforce, p. 6.  Looking at the ONR alongside DNSR  and the Environment Agency, the report criticised “overlapping systems and multiple regulators” ⁴⁶ Fingleton J, Nuclear Regulatory Review 2025, GOV.UK, 24 November 2025, www.gov.uk/government/publications/nuclear-regulatory-taskforce, p. 20.  and called for a simplification of the regulatory landscape. 

To achieve this, the report recommended that the ONR assumes more of a leadership role across the nuclear regulation landscape. It called for a Commission on Nuclear Regulation to be set up to facilitate collaboration between regulators, with the ONR acting as the default lead regulator. The report also recommends that the DSNR be absorbed into the ONR, with the latter setting up a dedicated defence directorate.

In response to the Fingleton review, the government published a strategic steer for the nuclear industry which reiterated calls for more collaborative “one-team regulation” and less “wasteful gold-plating”. ⁴⁷ Department for Energy Security and Net Zero and Prime Minister’s Office 10 Downing Street, Prime Minister's strategic steer to the nuclear sector following the 2025 Nuclear Regulatory Taskforce's Review, GOV.UK, 26 November 2025, www.gov.uk/government/publications/prime-ministers-strategic-steer-to-the-nuclear-sector/prime-ministers-strategic-steer-to-the-nuclear-sector-follow…  The ONR’s chief executive Mike Finnerty was receptive to the review, stating that the ONR was “ready to implement recommendations that remove any unnecessary burden from the regulatory framework, while maintaining rigorous safety standards”. ⁴⁸ Department for Energy Security and Net Zero, Ministry of Defence, Miliband E and Pollard L, ‘Taskforce calls for radical reset of nuclear regulation in UK’, GOV.UK, 24 November 2025, www.gov.uk/government/news/taskforce-calls-for-radical-reset-of-nuclear-regulation-in-uk