The chimney stack is on top of the first generation reprocessing plant and provided ventilation to a fleet of reprocessing plants.
The 60-year-old structure no longer meets modern construction standards and therefore has to be removed. Its position on one of the most congested nuclear sites in the world has made this a complicated and lengthy process.
At 61 metres tall, on top of a 61-metre building, it was the tallest structure on the site, until a modern replacement was built. Conventional demolition techniques like explosives and cranes cannot be used in such a crowded, hazardous environment.
Sellafied Ltd has worked with Nuvia and Delta International, who have brought specialist demolition expertise and innovative ideas to the project. A self-climbing platform has been designed, engineered and installed to act as a podium so that workers can access the chimney.
Using hand tools like drills, hydraulic breakers, concrete crunching jaws and plasma steel cutting torches, workers will remove each piece of concrete and steel from the stack by hand to a waiting waste skip.
The demolition started in October, with workers accessing it from the circular platform, which is held in place by friction, and moves up and down the barrel of the stack.
Stuart Latham, head of remediation at Sellafield, said: “Cleaning up our legacy facilities safely, quickly and cost-effectively is our absolute priority, so are delighted to now see the stack coming down after four years of preparation.
“Given the structural integrity of the stack, its location in the heart of the site and the fact that this new technique has never been used here before, the planning has been comprehensive. The project demonstrates the challenges of decommissioning the Sellafield site.
“We couldn’t move a crumb of this chimney without building a modern replacement first, so this has been a complicated project, made easier by working closely with our supply chain.”