Sellafield: Nuclear waste dustbin is cleaning up its act. Dorothy Gradden is standing in front of a tall, algae-covered concrete wall in the heart of Sellafield, Britain’s biggest and most hazardous nuclear waste site. “That’s the outside of the pond,” she explains. On the other side of the wall, beneath the surface of the water, lie 1,500 tonnes of radioactive sludge and 1,300 skips that contain corroding spent nuclear fuel. Known as B30, or unofficially as “Dirty Thirty”, this pond, cased in decaying 1950s concrete and open to the elements, is widely regarded as the most dangerous industrial installation in Europe. The algae coating its outside? That’s the least of the concerns. “What we don’t want to do is start pressure-washing the walls,” Ms Gradden, Sellafield’s head of legacy ponds, says. “You really don’t want to be prodding and poking and taking the top layer s of the concrete off. If we had a crack in our pond wall and we lost water, the water would obviously contaminate all the facilities around it. But if the fuel or radioactive sludge dried out, there’s a risk of airborne contamination and that could take the [contamination] activity off site. We wouldn’t need to evacuate West Cumbria but we would certainly be going to shelter for many days.” Reprocessing is now winding down as the last of the fuel from the Sixties Magnox reactors is dealt with and it no longer makes commercial sense to keep processing fuel from the Seventies and Eighties AGR reactors (whether it was ever a good idea is a moot point – Britain has yet to find a use for the plutonium stockpile). From 2021 the focus will shift solely to decommissioning, which on current forecasts will take at least another century and cost £90 billion. Now though, aided by technology, things are picking up. From a vantage point on the roof overlooking the rust-stained B30, our personal dosimeters chirping away at the radiation, Ms Gradden points down to a series of coloured cables snaking across the pool, between the seagulls, and down into its depths. “All of these lines you can see have ROVs [remotely operated vehicles] on the end of them,” she says. Initially ROVs designed for submarine rescues were used but “they would last in some instances hours because the electronics were affected by the radiation”. New models had to be developed; these ones have extensions a bit like an elephant’s trunk. “They’re like a nuclear vacuum cleaner,” Ms Gradden says. “They’re hoovering sludge.” The new technology has also brought new skills into demand. In the building adjoining the B30 pool, we enter a small room that looks at first glance like a student living room: three young men are sat clutching joysticks, huddled around TV screens. Luke, Ash and Jack, all in their early twenties, are taking it in turns to “fly” another ROV. Skills honed in computer gaming? Luke smiles: “It helps.” By 2022 Ms Gradden aims to have removed 90 per cent of the sludge and by 2024 “we will be in a much safer position” with remaining items washed of radiation; by the early 2030s the pond could be drained and on current plans it may be demolished in the 2050s. Technological advances are helping to make some savings but another more fundamental change also appears to be bearing fruit. Management of Sellafield Ltd was outsourced in 2008 but taken back under NDA control in 2016 after a series of failings. Executives say this approach allows it to adapt to the challenges as they unfold rather than sticking to strict commercial targets.
Times 8th May 2018 read more »