The team of underwater experts explored new depths at the former nuclear power station, with the task of cutting up old fuel storage skips and other redundant equipment as part of work to dismantle the site.
The team tackled their first UK ‘nuclear dive’ at Magnox’s Dungeness A Site in 2016. Bringing valuable learning from their work at Dungeness, the team arrived on site at Sizewell A in October 2017.
The divers, who wear full protective suits and are shielded from radiation by the water in the ponds, successfully cut up and ‘size reduced’ all 35 skips left in the ponds.
The team also cut up around 100 tonnes of other redundant equipment during the dives before removing all the radioactive sludge from the pond floor.
During the operational life of the power station, the ponds were used to store thousands of used nuclear fuel rods, held in metal skips, after they were discharged from the reactors. After the last fuel was transferred to Sellafield for reprocessing, the skips and a range of other waste items, including radioactive sludge, were left behind under the water.
Conventionally, pond clean-out is done using remotely operated equipment to lift the whole radioactive skips and other pond furniture clear of the water, exposing them to the air, where they are carefully cut up and decontaminated. This process is slow with potential radiation dose risks for workers.
Using this innovative underwater decommissioning technique, radiation levels for workers were around 20 times less than with conventional techniques. As well as reducing the overall radiation dose for workers, the diving technique has a lower environmental impact, is quicker and more efficient, resulting in greater value for the UK taxpayer.
Divers complete ponds mission at Sizewell A Site
David Rushton, Programme Manager for the Nuclear Decommissioning Authority which owns Sizewell A and 16 other UK nuclear sites, said:
Using divers at Sizewell is a fantastic example of Magnox taking an innovative approach to decommissioning and hazard reduction.
The end of the work to remove radioactive waste from Sizewell’s ponds will mark another successful step towards cleaning up the UK’s earliest nuclear sites. We’ve learned valuable lessons and gained some useful experience in ponds decommissioning which could help our work to reduce the hazards at the NDA’s other nuclear sites.
The ponds are set to be completely emptied and drained by the end of 2019.