PART of the Dounreay nuclear site that has been shut down for a week following a leak of radioactive fluid is due to reopen in the next few days.
A treatment plant destroying liquid coolant in the Dounreay Fast Reactor (DFR) was closed on 8 October after drips of caustic liquor from pipework in a shielded cell were detected by the monitoring systems.
The plant was immediately shut down and the leak isolated and stopped.
Dounreay Site Restoration Ltd (DSRL), the company in charge of the decommissioning of the plant, said there was no release of radioactivity to the environment and workers were not in danger.
It has since been revealed that about one litre of fluid leaked out through pinhole breaches of a pipe.
A DSRL spokeswoman said a piece of the stainless steel pipework has now been cut out and will be inspected to establish the cause of the leak. In the meantime a new piece of pipe will be fitted.
Workers had to wait for replacement parts to be delivered to the facility near Thurso before repairs can be completed, but the plant is expected to reopen early next week.
The amount of liquid released into the cell was extremely small and was contained in the cell. It posed no danger at any time to either staff or environment, the spokeswoman said.
She added that the leak would not delay the March 2012 deadline to destroy the liquid metal coolant in the reactor.
The Scottish Environment Protection Agency (Sepa), the Office for Nuclear Regulation and the Nuclear Decommissioning Authority were all informed immediately the leak was isolated.
DSRL said it will work with regulators on an investigation into the reasons for the leak.
A Sepa spokeswoman said officers carried out an inspection at the site and confirmed the seepage was contained within the plant and there was no release to the environment.
But Stan Blackley, chief executive of Friends of the Earth Scotland, said: “Once again, we receive more bad news from Dounreay.
“While this incident is reported to have been minor, and to have caused few problems, it highlights once again that Scotland’s nuclear infrastructure is growing old and unreliable, that the decommissioning of this infrastructure comes at enormous risk and cost, and that the ghost of Scotland’s nuclear past will be with us a long way into the future.
“It is a reminder that Scotland’s remaining nuclear power stations should be decommissioned as soon as possible, and that Scotland should move towards a renewable-powered future as a matter of urgency.”
Dounreay is being returned to a near-greenfield site at a cost of £2.6 billion including decommissioning the DFR by 2025 at a cost of £240 million.
The DFR was an experimental fast breeder reactor that operated from 1959 to 1977.
It was connected to the National Grid in the 1960s, when it was the world’s first fast reactor to produce electricity for public consumption.