'Small fire' dealt with at Dounreay nuclear site in Caithness
A small fire broke out in part of Dounreay's Prototype Fast Reactor facility in the early hours of Tuesday.
Dounreay Site Restoration Limited (DSRL) said the alarm was raised at 01:30.
The Caithness site's fire brigade extinguished the blaze in the PFR's sodium tank farm within 30 minutes.
DSRL said no-one was hurt in the incident and the Nuclear Decommissioning Authority and regulators had been informed.
The reactor ceased operating in 1994 and is more than halfway through a process of being decommissioned.
More than 1,500 tonnes of sodium, a material used when the reactor was in operation, has been safely destroyed so far.
Tuesday's fire occurred in a building where tanks are used to store sodium.
Work to dispose of the remaining sodium has been suspended to allow for an investigation into the fire.
Dounreay is being cleaned up and shut down in a £1.6bn project, which should be completed by 2025.