Cobalt isotopes that have been sitting in British storage ponds since the 1950s are finally being recovered, using miniature submarines. The project involves moving hundreds of the cartridges retrieved from Sellafield Ltd’s Pile Fuel Storage Pond and First Generation Magnox Storage Ponds.
“A few years ago remotely operated vehicles were thought of as expensive toys, but they are now becoming an integral part of our plan to clean up for our legacy fuel storage ponds. We are now seeing the removal of decades-old material from Sellafield’s legacy ponds on a daily basis, significantly reducing the hazard at these historic facilities,” Dorothy Gradden, head of the First Generation Magnox Storage Ponds, said in a press release.
Much of the waste currently being retrieved is made up of cobalt isotopes that were originally used in radiotherapy treatment and to sterilize of medical supplies. Some were also used for the defense industry, and in research. Cobalt has a fairly short half-life, which means the radiation naturally decays quickly, however this material still requires careful handling. ROVs are used to safely repackage the cartridges to minimize the radiation dose to the workers.
“We have developed the ROV capability to deal with underwater, hazardous problems that need to be dealt with remotely and I’m proud to say that even the US Navy has implemented some of our innovations developed here at Sellafiel,” Gradden said. “New potential uses for ROVs include floating fuel skips and large pieces of kit off the pond floor, after all if they can lift a sunken cruise ship from the sea bed, why can’t we lift skips that our in-pond crane can’t reach?”