Sodium storage concerns remain at Dounreay amid ‘enhanced’ safety attention at former nuclear site
Concerns remain over the storage of sodium at Dounreay and long-term plans to dispose of it, according to a new report from the nuclear regulator.
The Chief Nuclear Inspector (CNI) published his annual report on the nuclear industry in Great Britain, covering the year from 2024 to 2025, on Monday.
In it, he outlines the performance of the sector as a whole, as well as highlighting particular issues at individual nuclear sites.
The Office for Nuclear Regulation says that in areas where performance did not meet the expected standards during 2024-2025, it held the industry to account to influence improvements.
This included a focus on sites – including Dounreay – that were subject to enhanced or significantly enhanced regulatory attention, with the current attention levels detailed in the report.
The CNI’s report explains that the timescales for the decommissioning of the prototype fast reactor (PFR) at Dounreay have been extended, with additional resources and regulation required.
“Dounreay has been focused on a number of key asset improvement projects to ensure their assets will support future mission delivery,” the report adds.
It also explains that industrial action which took place at the site during 2024 “had an impact” on work at the site, although it added that Dounreay’s “commitment to safety and security during this period has been maintained”.
The site is currently at “enhanced” regulatory attention level for nuclear safety.
The CNI report explains: “Dounreay is currently in enhanced regulatory attention for safety due to the current condition of a number of site assets (such as buildings, electrical systems, steam systems), management of conventional health and safety legislation (such as compliance with COMAH, DSEAR) and the level of management and organisational change affecting organisational safety culture.
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“These matters have been discussed with NRS and site management, who demonstrate an understanding that the route out of enhanced attention was not just about addressing the associated RIs, but in dealing with the root causes of why the regulator is identifying these issues.
“We continue to hold Dounreay to account in these areas, as well as establishing regulatory arrangements to support Dounreay to return to routine regulatory attention.”
It goes on to explain how in February 2024, an improvement notice was issued over how Dounreay stores bulk alkali metal in the PFR complex.
“Dounreay has now implemented improvements to the storage arrangements, including improved water protection and an enhanced monitoring regime which has enabled us to close out the improvement notice,” the report states.
“Notwithstanding the closure of the improvement notice, we still remain concerned about the interim storage of sodium at the site and the long-term plans to manage the final disposal, which is a factor in the site’s enhanced regulatory attention level.”
There were three “reportable injuries” noted at the site during the 12-month period covered by the report, up from two in the previous 12 months.
The report notes an incident at Dounreay that the ONR reported to the Department for Energy Security and Net Zero when water levels within a redundant carbon bed filter located in an external area near fuel cycle facilities showed water was leaking from the bed.
The report shows that around a litre of water a day was leaking in the incident, reported in July 2024. ONR and the Scottish Environment Protection Agency (SEPA) were notified and monitoring of the area was increased.
The report states: “We have confirmed that there were no immediate consequences from the water losses and consider that NRS Dounreay’s follow-up actions are reasonable.
“Dounreay has appropriately considered the health and safety aspects of this event and further follow-up on this event by us is not planned. No site workers have been harmed or exposed to radiation as a result of this issue.”
Overall, Dounreay’s security performance is described as “satisfactory” and it performs “adequately” in terms of cyber security. “Due to its remote geographical location, the Civil Nuclear Constabulary continues to employ a variety of methods to attract new recruits and retain the required officers to meet security requirements.”
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’d call 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.”