Sellafield has been called the most dangerous place in the UK, the most hazardous place in Europe and the world’s riskiest nuclear waste site. At its heart is a giant pond full of radioactive sludge, strewn with broken metal, dead animals and deadly nuclear rods. The solution to clearing up Sellafield’s nuclear waste and retrieving the missing nuclear fuel? Robots, of course. And to tackle this mammoth task, the robots are being forced to evolve. Sellafield’s First-Generation Magnox Storage Pond is a giant outdoor body of water that’s the same size as two Olympic swimming pools. It was built in the 1960s to store used fuel rods from the early Magnox reactors – which had magnesium alloy cladding on the fuel rods – as part of Britain’s booming nuclear program. In 1974, there was a delay in reprocessing; fuel rods started corroding and the pond became murky. The pool was active for 26 years until 1992 and is now finally being decommissioned as part of the £1.9 billion spent each year on Sellafield’s mammoth clean-up operation. The pond contains about six metres of radioactive water and half a metre of sludge, composed of wind-blown dirt, bird droppings and algae – the usual debris that builds up in any open body of water. Unlike other mud, it conceals everything from dropped tools and bird carcasses to corroded Magnox cladding and the remains of uranium fuel rods. A number of robotic creations have been used to get to the bottom of the pool’s sludge but struggle to break through the hostile environment. Tethered swimming robots do not have the sensors to find objects in the fine mud, and lack the leverage to lift chunks of metal. Experience at Fukushima has shown robots that are not well adapted to the environment are a waste of time. Enter Cthulhu, a tracked robot that can drive along the pond bed, feeling its way with tactile sensors and sonar. The robot, which is currently in development, is approaching Sellafield’s problem differently. The robot will be able to identify nuclear rods and then pick them up. “Rather than trying to mimic a human, we’re building a robot that can do things humans can’t do with senses that humans don’t have,” says Bob Hicks of QinetiQ, which is leading the project. The name stands for ‘Collaborative Technology Hardened for Underwater and Littoral Hazardous Environment,’ but it’s also a nod to Cthulhu, the godlike alien created by HP Lovecraft: both are amphibious, dwell in strange surroundings, and have sensory feelers.

Wired 14th June 2018 read more »


Published: 14 June 2018