When the plant was operating, the ‘amber’ area housed equipment to dissolve uranium in acid to recover the reusable material and remove the waste products.
The nature of the work caused high levels of contamination and workers were forced to don cumbersome air-fed suits before they could enter.
Industry regulators the Nuclear Installations Inspectorate placed a high priority on the decontamination of the amber area. The Nuclear Decommissioning Authority who own the site were also keen to see the clean-up take place.
A team of 12 workers from DSRL, NDSL, Doosan Babcock, and Nuvia, managed by DSRL, carried out the work. They were assisted by health physics operators from Nuvia, and were able to call on their colleagues in other facilities when necessary.
Before any clean-up work could start, the ventilation system had to be upgraded. Redundant glove boxes and solvent extraction plant were stripped out, cleaned up and size-reduced.
Four-inch thick slab tanks that once held radioactive liquid were removed, and the team employed a remotely-operated Brokk to help them demolish the 32 reinforced concrete plinths that separated the tanks.
Approximately 130 tonnes of concrete rubble was sentenced as low level waste.
DSRL project manager David Manson described the project as a “daunting task”.
“The amber area was vast, and full of equipment, as well as being highly contaminated,” he said.
“We tackled the work a bit at a time, and made steady progress. We have proved that we can take on large decommissioning jobs and get them done.”