The delay tank system for the Steam Generating Heavy Water Reactor at Winfrith Site has been decommissioned, removing another significant part of the reactor system.
The two 70m3 tanks once held all the active liquid produced by the reactor before it was processed for disposal.
After the contaminated tanks were drained, the decision was made to encapsulate the remaining active material, including liners, silt and sludge, with grout.
A remotely-operated Brokk 330 vehicle was found to be the most effective method of breaking the tanks apart.
Project Manager Eddie Morrison said: “We successfully managed to reduce dose levels to operatives by changing the head of the Brokk to a bucket, ensuring that all rubble was pulled away from the contaminated tank.
“And all the Brokk operators had the same level of competence and were able to pre-empt machinery faults and replace parts without halting operations.”
By chipping away at the grout structure the first tank was reduced to 870 drums of waste material; and the second just over 800 drums.