The 61-metre high chimney no longer meets modern standards but – being on top of an old nuclear reprocessing plant and surrounded by buildings containing hazardous material – it cannot be blown down or smashed with a wrecking ball. Instead it is being brought down by hand, with the debris removed by tipping buckets.
The demolition is being delivered via a collaboration between Sellafield Ltd, supply chain partner Nuvia, and its subcontractors Delta International and Alimak Hek.
Demolition work started in October 2017 and a quarter of it is now down. It is due to disappear completely by 2020.
Sellafield head of operations Simon Rowe said: “We’ve safely demolished 15 metres of the stack, taking a quarter off its height. That means it no longer poses a risk to any of the active plants around it.
“It’s a major achievement and removes the radiological risk associated with this landmark of the Sellafield skyline.”
As part of the contract Nuvia designed, built, tested and commissioned a self-supporting, climbing platform. The platform can climb the chimney at the speed of 5mm per second and its diameter can be adjusted to fit the taper of the chimney.
The self-climbing platform is similar to the method used to demolish chimneys at London’s Battersea Power Station. It is held in place by 84 rubber pads which press against the barrel of the chimney. Only friction prevents it from falling.
To move upwards, half of the pads are released, raised and tightened. The others are then raised and the platform inches up to the top of the stack.
It began its 61-metre ascent in November 2016 and arrived nine months later in August 2017.