The UK’s nuclear industry maintained high standards of safety, security, and safeguards in 2024/25, the Chief Nuclear Inspector (CNI) has today announced.
The overall performance of the sector remained satisfactory, with most Office for Nuclear Regulation (ONR) inspections confirming good levels of compliance, the CNI annual report shows.
There was a slight drop in reported significant events on nuclear sites, and a small rise (16%) in incidents overall, with notable improvements in performance across Ministry of Defence sites and some increased regulatory attention required at operating reactors and specific decommissioning sites.
Nuclear site health and safety (NSHS) has remained a regulatory priority area during the past year due to variable and declining performance in 2023.
ONR adopted a strategic and targeted approach to NSHS and a small decrease in the number of Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) events has been recorded during 2024/25 which is positive progress.
Cyber security at nuclear sites has also received sustained focus from ONR's inspectors which has helped achieve a deeper understanding of cyber security capability at both the dutyholder and sector-wide levels.
Both cyber security and nuclear site health and safety will be retained as priority regulatory areas for the year ahead, with conventional health and safety and fire safety chosen as the topic for our 2026-27 CNI Themed Inspection.
The Chief Nuclear Inspector’s annual report highlights many positive achievements across the sector during 2024/25 including:
- ONR granting the nuclear site licence for Sizewell C
- ONR permissioning the installation of the Unit 1 reactor pressure vessel at Hinkley Point C, the first such activity in the UK for 30 years
- Withdrawal of 98 regulatory specifications from former Magnox decommissioning sites, delivering both cost and time benefits to the dutyholder and ONR
- Permissioning the docking of two nuclear submarines at Devonport Royal Dockyard ahead of required timescales
The completion of the CNI Themed Inspection on climate change which showed no fundamental issues in relation to the current safety of nuclear sites against external hazards
There has been a significant step forward in the government's nuclear energy ambitions during the last year, with the sector in an ever more dynamic operating environment aligned to the UK's drive to maintain energy security, achieve net zero and deliver successful major investment in nuclear defence.
As a proportionate regulator, ONR recognises its key role within that climate and is committed to keep working in an increasingly enabling and collaborative way - supporting cost-effective, efficient nuclear operations and technological advancements while protecting workers and the public.
The government’s ongoing regulatory taskforce review is an opportunity to examine the strengths and challenges within the current framework and ONR continues to provide expertise to help inform the taskforce’s final report.
During the past year, ONR has worked with EDF on its lifetime extension ambitions for its operating reactors (Heysham 1 and Hartlepool, and Heysham 2 and Torness prolonging generating lives until March 2028 and March 2030, respectively), adopting an enabling regulatory approach while addressing any ageing effects across the operating AGR stations.
At Sellafield, ONR has sought improvements in the site’s high hazard and risk reduction activities with progress at the legacy ponds and silos slowing due to technical difficulties, supply chain issues and equipment reliability challenges.
There has been noteworthy steps forward, however, with waste being retrieved from all of the legacy facilities and the BEPPS-DIF facility becoming fully operational to store waste from the high hazard Pile Fuel Cladding Silo, one of Sellafield’s biggest challenges in recent years.
In areas where performance did not meet the expected standards during 2024-2025, ONR held the industry to account to influence improvements.
This included a focus on sites that were subject to enhanced or significantly enhanced regulatory attention - with the current attention levels detailed in this year’s report.
Mike Finnerty, ONR's Chief Nuclear Inspector, said:
"We’ve seen satisfactory standards of safety, security, and safeguards across the nuclear sector in the UK in 2024/2025, and the improvements secured back up why the UK industry is highly regarded globally.
"However, we cannot be complacent, given the substantial growth in both the civil and defence nuclear spheres, and it's vital to maintain high performance that ensures that local communities and workers are protected.
"We will need to embrace an increasingly enabling and collaborative approach that will be crucial in driving progress and to uphold the strong track record of high standards across the nuclear industry.
"I'm calling on dutyholders to continue to learn from experience so that activities of construction, operations and decommissioning - throughout the whole nuclear lifecycle - support the successful, safe and secure delivery of UK energy and defence ambitions."