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The Mini Robot Submarines Fishing for Nuclear Waste

A team in England is using the remote operated vehicles to pluck out medical isotope cartridges from a nuclear spent fuel storage pool.
​Screengrab: ​YouTube

​Somewhere in a deep pool in England, miniature submarine robots are delicately plucking up 60-year-old tubes of radioactive medical waste, one by one.

Nuclear storage pools are used to stash away the radioactive spent fuel from a plant until it is has cooled enough to be moved into dry storage (though we're still tryin​g to figure out what to do with it when we pull it up out of the pools). At tw​o of England's largest nuclear storage pools, that fuel includes cartridges of radioactive cobalt isotopes, most likely coba​lt-60, which is used in medicine for radiotherapy and the sterilization of medical supplies.

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Since cobalt isotopes have relatively short half-lives, the cartridges became less radioactive fairly quickly, but they've remained in the bottom of these pools since they were first deposited back in the 1950s and 60s. Now, a team at Sellafield Ltd, a nuclear decommissioning company, is using remotely-operated submarines (ROVs) to pull the cartridges up and place them in dry storage.

"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," Dorothy Gradden, the head of the First Generation Magnox Storage Ponds, one of the storage pools in question, said in a press release. "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."

The team estimates there are about 800 cobalt cartridges stored in open-top dumpsters on the floor of the pool. Each cartridge is about three feet long, weighs about 13 lbs, and has to be extracted individually.

Originally, the team only used ROVs to inspect the pools and make sure everything was secure, but eventually they realized the machines could do some actual manual labor, reducing the need for humans to put themselves at risk of exposure. Now, they're dreaming up even more ways the robot submarines can help out around the pool, including lifting entire dumpsters (or skips, as they're called in the UK) of fuel out of the storage pond.

"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?" Gradden said.