The 110m structure – the scene of Britain’s worst nuclear accident – will begin to disappear later this year.
A 152m crane – just six metres shorter than the Blackpool Tower – has been constructed to bring it down.
It will begin work this autumn, removing and lowering chunks of the chimney cut out using diamond wire saws.
Duncan Thompson, the Nuclear Decommissioning Authority’s Sellafield programme director, explains: “The complex task of decommissioning and demolishing the Windscale Pile One Stack has reached an important stage.
“It is another example of the ingenuity that goes into solving the UK’s decommissioning problems. Once demolition begins it will be a very visible demonstration of the work being done to make Sellafield a safer place.”
The Windscale Pile One chimney, with its distinctive top-heavy appearance, has dominated the Sellafield skyline for nearly 70 years. Its filtration system was a last-minute addition, placed unusually at its summit.
The first piece to go will be the square-shaped ‘diffuser’ at the top. As buildings containing nuclear material surround the stack, traditional demolition techniques like explosives cannot be used.
George Frost, project engineering manager, adds: “We’re making visible progress on this demolition, and it won’t be long now until we start to see the diffuser removed. The chimney is one of the iconic legacies of Sellafield’s past, so the skyline change as the chimney is removed will be significant.
“This has been a challenging piece of work, so everyone is pleased to see work progressing. This is thanks not only to the Sellafield and supply chain teams involved now, but over more than a generation.”