The UK Office for Nuclear Regulation (ONR) has identified leaks from low-level radioactive waste pits in its latest inspection at the Dounreay site in Scotland. Dounreay was the UK’s former fast reactor test facility, which operated from 1955 to 1994. It is now being decommissioned. Ongoing clean-up and dismantling work is continuing.
Although the ONR statement was issued in March followed by an inspection in April that was published in July, it has only now become the focus of media attention, with The Scotsman, the BBC and the John O’Groats Journal all reporting on the situation, among others.
ONR said in March that it had served an improvement notice on Dounreay site operator Nuclear Restoration Services (formerly Magnox Ltd) for shortfalls in arrangements for storing alkali metals at the site. “Buildings used to store alkali metals, predominantly sodium, were leaking in rainwater – with pools observed where containers of these metals were being kept,” the statement said. “ONR inspectors judged that the prolonged period of exposure to moist and damp conditions is resulting in degradation of the barriers for safe storage of these chemicals.”
ONR added: “Although nobody was harmed as a result of these shortfalls and there were no radiological consequences, ONR has concluded there was the potential for serious personal injury, if workers had been exposed to these hazardous materials.”
Ian Phillips, ONR’s Head of Safety Regulation for Decommissioning, Fuel & Waste sites, said: “All nuclear site licensees have a legal requirement to ensure that hazardous materials are stored in suitable conditions. The storage arrangements for these materials were inadequate and fell below legal compliance and the high standards that we expect to see. We will be closely monitoring the Dounreay site’s response to this notice to ensure they take the required steps to improve their existing arrangements.”
ONR said it had issued the improvement notice to NRS which was required to provide details to ONR by 1 April “on the actions they intend to take to address these shortfalls with full compliance sought by 27 June 2025”.
ONR said its inspection of the site (Inspection ID: 52970) in April aimed “to conduct a series of interventions focusing on Dounreay’s ability to maintain its assets in a safe manner” over 2024-2025 and to “consider a number of elements of Dounreay’s asset management arrangements”. The purpose of the inspection was “to seek assurance of sustainable programmes for management of ageing assets against:
- Effective strategies for the characterisation, monitoring, trending and analysis of ageing, at facility, system and component level;
- Commitment to ensure that the right level of organisational capability to sustain specialist safety case and other technical capability to substantiate on-going safe operation;
- Methods to identify and manage obsolescence in facilities for their operation design life and any potential lifetime extensions;
- Sustained focus and commitment to ongoing investment in plant, people and processes concerned with ageing management.
ONR said the inspection was informed by previous walkdowns where significant deterioration of the Prototype Fast reactor (PFR) turbine hall building structure had been observed. “During the inspection we sampled Dounreay’s updated asset management strategy and value stream lifetime plans. We were content that these met the regulatory expectations detailed in the ONR Civil Engineering & Asset Management Technical Assessment Guides.”
The inspection included a walkdown of the PFR, the Dounreay Material Test Reactor (DMTR), and the D1208 Facilities that once held storage tanks of liquid radioactive waste, as well as a general walkdown of the secure Fuel Cycle Area (FCA). “The ONR Civil Engineering specialist inspector was content that the buildings in the FCA, DMTR, and D1208 were in good condition for their age with only minor defects noted which had suitable rectification plans to address.” However, “we noted that the conditions in PFR Steam Generator (SG) Hall and Turbine Hall were poor with significant corrosion of the steel structure”. On this basis we awarded an Inspection rating of AMBER and will issue formal Regulatory Advice to Dounreay on its regulatory duties to maintain the PFR buildings in suitable conditions.
ONR concluded that the DMTR and D1208 buildings’ condition meets expectations “and that Dounreay have adequate proposals and arrangements in place to ensure future asset care”. As to the PFR Turbine Hall, ONR said “these matters represent a departure from relevant good practice and corrective action is required”.
The ONR civil engineering specialist noted that Dounreay’s agency supplied civil engineering specialist had proposed a series of works to prevent further degradation. “These were described during the inspection, and the ONR civil specialist concluded these proposals would likely meet regulatory expectations subject to their being sufficient margin left in the civil engineering structure to substantiate the building through to its ultimate demolition in line with the site Lifetime Plan.” However, “Due to the poor condition of the steel structure of the PFR SG Hall and Turbine Hall we awarded an Inspection rating of amber and will issue formal Regulatory Advice to Dounreay on its regulatory duties to maintain the PFR buildings in suitable conditions.”
A spokesperson for NRS told The Scotsman that Dounreay is working closely with the regulator to implement the agreed action plan. It is not clear why the issue has become prominent now. Workers at Dounreay undertook strike action in May and June over pay supported by the Unite, Prospect and GMB unions. However, the action was called off on 5 July after union members accepted a revised deal and returned to normal working on 8 July.
At a recent meeting of Dounreay Stakeholder Group, Acting NRS Managing Director John Grierson admitted that about 95% of the decommissioning and hazard-reduction programme had been affected by the dispute but said he did not believe it would have any lasting effect on the length or cost of the clean-up.
In March, it was reported that the Dounreay decommissioning programme would now continue until the 2070s during which some £7.9bn ($10.4bn) would be spent on the work. This compares with previous end dates of 2023 and more recently 2033 published in Nuclear Decommissioning Authority business plans with costs put at £1.9bn and £2.9bn. A Dounreay spokesperson said at the time: “The estimate for delivering the revised lifetime plan to take the Dounreay site to its interim end point will form part of the Nuclear Provision, and be published in the NDA 2023/24 annual report in the summer. We are committed to delivering the Dounreay mission as effectively and efficiently as possible.”
