Work has begun on the "challenging" task of removing radioactive fuel elements stuck inside the most famous of Dounreay's reactors.
Closed since 1977, the Dounreay Fast Reactor is known for its dome-shaped exterior.
Almost 1,000 fuel elements have been in the reactor for years after the work to remove them was halted because they were swollen and jammed in.
New technology has now been developed to make it possible to remove them.
It could take three years to complete the job at the nuclear power site near Thurso in Caithness.
Ron Hibbert, senior project manager at Dounreay Site Restoration Limited, said: "Emptying the reactor vessel of this material is one of the biggest engineering challenges we face in decommissioning the site."
Once all the elements have been removed work can begin on dismantling the reactor.