Specialist scuba divers are working to remove radioactive waste from Sizewell A’s nuclear fuel storage pond using new techniques which will mean they receive lower radiation doses.
The work to clear the ponds is likely to take 10 months with the divers tasked with cutting up the metal radioactive skips which once held the thousands of used nuclear fuel rods after they were discharged from the reactors.
After the last of the fuel was transported to Sellafield for reprocessing, the skips and a range of redundant items, including sludge, were left behind in the water.
Usually pond clean-outs are done using remotely-operated equipment to lift the skips clear of the water, exposing them to the air, where they are carefully cut up before decontamination, storage and eventual disposal. This process is slow with potential radiation dose risks for workers.
The team of American underwater experts, wearing full protective suits and shielded from radiation by the water, can cut up the skips more safely, access awkward areas more easily, making the whole process safer, faster and more productive.
Steve Franks, Sizewell A site ponds programme manager, said: “The scale of work to be delivered by the divers is huge. Although we only have one pond to decommission, the inventory of the ponds is larger than at Dungeness A but we will still be looking to speed up the work wherever it is safe to do so.”
The site is owned by the Nuclear Decommissioning Authority (NDA). Geoff Suitor, Head of the Magnox Programme for the NDA, said: “Magnox’s implementation of innovative approaches, such as the use of divers to handle radioactive waste in ponds, contributes to real progress in reducing risks and hazards at the Magnox sites.
“Together, we are successfully cleaning up and making safe the UK’s earliest nuclear sites on behalf of our communities and the environment.”
In addition to a reduction in the overall radiation dose for workers, compared with traditional methods, the diving technique has a lower environmental impact.
The first dive took place recently and focused on surveying the pond floor, transferring sludge into a purpose-built tank, setting up cutting equipment and cutting the first of 35 skips, which are classified as Intermediate Level radioactive waste.
During more than 250 dives at Dungeness A, a number of new ideas emerged including the use of lightweight plastic platforms for divers to stand on when exploring uncharted areas of the pond floor.
The team of 12 nuclear divers is supplied by US contractor Underwater Construction Corporation (UCC), which also carried out the Dungeness A project.
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