Underwater experts tasked with cutting up former fuel storage skips and other equipment at the Sizewell A plant in Britain have completed their work nearly two months ahead of schedule, Magnox Ltd. announced last week.
Magnox said, "the team of underwater experts explored new depths at Sizewell A."
There were 12 divers from Underwater Construction UK Ltd involved in the project. A video clip shows them in action.
"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 company said.
The are shielded from radiation by the water in the ponds. The team used cutting techniques to ‘size reduce’ all of the 35 skips left in Sizewell A’s pond, according to the statement.
During the dives, the team also cut up around 100 metric tons of other redundant equipment before removing all the radioactive sludge from the pond floor.
The ponds had been used to store thousands of used nuclear fuel elements, held in metal skips, after they were discharged from the reactors. After the last of the 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 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 of decommissioning the waste items in air.
As well as a reduction in the overall radiation dose for workers, the diving technique has a lower environmental impact, is quicker and more efficient -- a benefit to taxpayers, Magnox said..
Steve Franks, Sizewell A Site Ponds Programme Delivery Manager, called the project "a major success for the site, using this technique has saved time on the project and money for the UK tax payer and provided a significant reduction in dose to workers."
Franks applauded the technical know-how that was originally obtained at Dungeness A. The same techniques were used at Sizewell A "and we have been able to now share our further learning across the Nuclear Decommissioning Authority estate which could, in future, provide yet more cost savings," he said.
David Rushton, Program Manager for the Nuclear Decommissioning Authority who own Sizewell A and 16 nuclear sites in the UK, said the milestone "marks another successful step towards cleaning up the UK’s earliest nuclear sites.”
Now that the divers have left, the next phase of work is to take the waste out of the ponds where it will be treated and safely packaged. The ponds are set to be completely emptied and drained by the end of 2019.
Here's the clip:
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