Radioactive waste exported to Peru from Scotland almost 10 years ago has been returned to the Dounreay nuclear plant in Caithness.
It cost £1.7m to return the material to Dounreay
It has emerged that 2.9 tonnes of thorium nitrate arrived safely at the site on Wednesday after a marathon sea and road trip from South America.
The waste was originally produced at the Caithness nuclear plant as a by-product of reprocessing.
It was exported to Peru in 1998 but could not be treated or disposed of.
Kukala, a company based in the Peruvian capital Lima, had originally planned to use the material to fuel gas mantles.
As Peru lacks any specialist treatment or disposal facilities, moves began last year to return the material to Scotland.
A team of 12 people from the Caithness site travelled to South America to prepare the waste for its month-long return journey.
The operation is thought to have cost the Nuclear Decommissioning Authority £1.7m.
The Dounreay plant's monthly bulletin stated: "The material was unused by the customer who did not have suitable facilities to process or dispose of it.
"A team from Dounreay travelled to Peru recently to package the material for shipment.
"It has now arrived back at Dounreay, where it will be conditioned along with other thorium held at the site to make it safe for long-term storage or disposal as intermediate-level waste."