The decontamination and waste handling facility, code named D1207, was built to serve Dounreay’s chemical plants and the next door Vulcan site. The electrical overhead travelling (EOT) gantry crane, which had a 7.5 ton capacity, was used to move large items of equipment such as flasks.
The lift was the culmination of a year’s work by a team of workers from site licence company DSRL and its decommissioning sub-contractors.
Before it could take place, the team decontaminated the entire surface of the ceiling and removed the redundant ventilation extract ducting from the building.
A roof hatch was also installed to give access to the mobile crane positioned outside the building.
The team waited for a relatively calm day to carry out the manoeuvre, as there was little margin for error in lifting the 8 tonne crane, which spanned the entire width of the building.
Once the cross-travel bogie had been lifted off the crane and lowered to the floor, riggers wearing radiation protection clothing and respirators fixed scaffold poles to the crane to prevent the slings slipping during the lift.
In one smooth move, the crane was lifted off its rails, turned ninety degrees and lowered to the floor.
The crane and bogie were cut up and sprayed with two coats of metal paint before being loaded into ISO containers for consignment as low level waste.
DSRL senior project manager Robbie Manson said that the removal of the crane was part of reducing the radioactive hazard in the building, and another step towards its eventual demolition.
“The next phase of work will be removing the contaminated floor and some of the walls,” he explained.
“We expect to be in a position early next year to begin de-sheeting the building and then to size-reduce the steel framework.”