A project to bury tonnes of radioactive waste from Dounreay in massive underground vaults has completed its first phase.

Two giant holes have been excavated near the site of the nuclear plant in Caithness.

They will be used to house huge specially constructed concrete vaults designed to hold low-grade radioactive waste from the nearby nuclear power plant, including contaminated paper and clothing.

Around 200,000 cubic metres of rock has been removed to accommodate the structures.

Once inside the vaults the waste will be monitored for 300 years, by which time its radioactivity will have dropped by 95%.

The decommissioning of Dounreay has been ongoing for almost a decade, and it hit the headlines earlier this year when it was labelled "the world's nuclear dustbin".

That came after it was revealed the site operators had taken ownership of waste from other countries for treatment but then were unable to return it.

Bosses say the latest stage of the project is proceeding on schedule.