The Nuclear Decommissioning Authority

Work on-track to demolish Dounreay criticality building

20 August 2008

The clean up of Dounreay’s plutonium criticality research facility is now complete and building is scheduled for demolition by the end of summer 2008. The facility, named D8550, was built over 50 years ago to facilitate a major programme of criticality experiments on plutonium-bearing materials.

The building housed a seven metre high and eight metre wide cell in which the experiments took place and was heavily contaminated.

Workers wearing bulky air-fed suits had to make over 5,000 entries into the area to clean it up. Once the 13mm thick steel pressure vessel that lined the interior had been cut up using oxy-gas torches and removed, the cell was declassified and closed off awaiting final demolition.

Meanwhile cleaning up the remaining active areas of the facility involved demolishing contaminated concrete walls using a Brokk semi-robotic machine.

Now, the last original ventilation fan has been turned off, and the building will shortly be handed over to the site’s demolition experts.

Randall Bargelt, the NDA’s programme director for Dounreay, said: “The demolition of the building will mark yet another milestone in decommissioning Scotland’s biggest civil nuclear site.”

NDA Assurance Director Jim Morse was escorted round the facility by the Project team when he recently visited the site. Mr Morse (pictured fourth from left) said it was impressive it was to be able to stand in an area which had once been so highly contaminated it was only accessible in a bulky airline suit.