RADIOACTIVE material was accidentally released at Scotland’s Dounreay nuclear site in a major environmental breach, The National can reveal.
An investigation was launched in June 2024 after Nuclear Restoration Services (NRS) – the firm which is responsible for the north Caithness complex’s clean-up and demolition – informed the Scottish Environmental Protection Agency (Sepa) of a potential leak of contaminated water.
Scotland’s environmental regulator confirmed that a “small leak” from a carbon bed filter had occurred.
Three different radioactive substances – alpha-emitting Radionuclides, alpha-emitting Radionuclides and Caesium-137 – were all released, according to the Scottish Pollutant Release Inventory (SPRI) data.
Monitoring from NRS didn’t detect any increase in radioactivity in groundwater downstream.
But Sepa found that the firm had breached environmental regulations and has ordered it to review its groundwater monitoring arrangements and “establish the extent of contamination” which has arisen from the leak.
Dounreay was opened on the north Caithness coast almost 70 years ago and was the UK's centre of fast reactor research and development until 1994.
Hundreds of Scottish workers are now involved in its decommissioning.
Last year, a watchdog – the Office for Nuclear Regulation (ONR) – raised safety concerns about the state of some areas at Dounreay, including corroded steelwork in a building being used to store drums of radioactive sodium, and leaks from low-level radioactive waste pits.
The Scottish Greens have told The National that this leak is “deeply concerning”.
“It is a telling sign that we must move away from unstable, harmful, wasteful energy sources like nuclear immediately,” the party’s MSP for the Highlands and Islands, Ariane Burgess, said.
“There must be investigations carried out to find out why this happened, and what can be done to ensure nothing of this nature happens again, including making polluters pay for the damages to try and repair our natural environment.”
She added: “Harmful waste being released into the environment, accidentally or otherwise, has a knock-on effect on our own lives and the world around us.
“We need to use the abundance of clean, green, safe and affordable renewable energy sources that Scotland is so fortunate to have. It is the only way to put an end to these harmful emissions, spills and radioactive by-products that have the ability to wreck the health of both people and the planet.”
A NRS spokesperson, meanwhile, said: “Dounreay is permitted to release low levels of radioactive gaseous and liquid effluent during the site’s decommissioning via authorised discharge routes.
“During 2024, we detected a release of contaminated water from a disused underground facility via an unauthorised route and took action to stop the release. We informed SEPA and kept them updated on our findings.
“We estimate the release was a very small fraction of our normal discharges via authorised discharge routes.”
A spokesperson for SEPA said: “In June 2024, Nuclear Restoration Services Ltd (NRS) notified SEPA of a potential leak of radioactively contaminated water from a carbon bed filter on the Dounreay site.
“It was subsequently established that there was a small leak from the carbon bed filter. Monitoring by the operator has not detected any increase in radioactivity in groundwater downstream.
“SEPA’s investigation concluded that the operator had breached conditions of its Environmental Authorisations (Scotland) Regulations 2018 (EASR) authorisation.
“To secure compliance, we have issued a Regulatory Notice requiring NRS to take specified steps, including reviewing groundwater monitoring arrangements and undertaking characterisation to establish the extent of contamination which has arisen from the leak from the carbon bed filter.”
