Great Britian’s nuclear industry has continued to operate safely and securely throughout the 2025/26 reporting period, the Chief Nuclear Inspector (CNI) announced today.
However, the CNI's annual report also highlights variability of performance between dutyholders and areas where sustained regulatory focus is still required such as cyber security and nuclear site conventional health and safety.
During the past year, the nuclear sector has operated against a backdrop of rapid technological advances, wider environmental pressures and geopolitical uncertainty which has meant the industry and regulators having to adapt and change. The publication of the Nuclear Regulatory Review 2025 was welcomed by the Office for Nuclear Regulation (ONR) which remains committed to supporting the safe and timely delivery of nuclear projects.
The government's nuclear energy ambitions have grown in recent years, and ONR will support this through its new rolling strategy, ONR Together, published in July 2026. This commits to delivering proportionate, enabling regulation that supports innovation and growth, while maintaining public confidence in safety and security.
Accelerated delivery will require a cultural shift and a greater focus on outcomes across the industry. ONR recognises its key role in enabling progress within the sector while maintaining rigorous safety and security standards.
Nevertheless, the CNI report highlights many positive achievements across the sector during 2025/26 including:
- Devonport Royal Dockyard Ltd’s return to routine regulatory attention for safety
- Progress in cyber security performance at Sellafield leading to a change in regulatory attention level
- Progress in EDF’s cyber security arrangements
- The successful transfer of Hunterston B Nuclear Power Station licence to Nuclear Restoration Services to formally enter the decommissioning phase
- Stronger industry engagement in nuclear sector innovation and improved supply chain performance
During the past year, ONR has overseen the continued safe and secure operation of the UK’s operating reactor fleet, following EDF’s lifetime extension decisions.
At Sellafield, ONR has sought improvements in the management of high hazard facilities and risk reduction activities. Progress at the legacy ponds and silos programme has remained slower than planned due to technical challenges, asset reliability issues and ageing infrastructure.
However, despite these challenges, waste is now being retrieved from all the legacy ponds and silos, a significant milestone in the long-term work to transfer historic stores of material using more fit-for-purpose and modern solutions. For the remediation area a risk-informed approach is being developed and piloted to support more efficient decommissioning.
Where performance fell short of expected standards during 2025/26, ONR held the industry to account to drive improvement. This included a focus on sites subject to enhanced or significantly enhanced regulatory attention, with current attention levels detailed in this year's report.
Nuclear site conventional health and safety has remained a key regulatory priority. Incident rates remain above the long-term average, indicating that sustained improvement has been limited.
The topic has therefore been chosen for this year’s Chief Nuclear Inspector’s Themed Inspection, with a particular focus on construction activity across the sector. The findings will be reported towards the end of next year.
Ensuring robust cyber security across the nuclear sector was a core regulatory priority last year, and ONR’s inspection programme showed an improving baseline capability in this area. However, it also confirmed that overall cyber security maturity remains below the level expected which will require continued regulatory focus.