The complex demolition of Sellafield’s tallest stack, at the nuclear power plant’s first-generation reprocessing plant, is nearing completion with just a 9m stub remaining.
So far, 52 metres of the structure have been removed as a result of a 30-month collaboration between Sellafield Ltd, demolition firm Nuvia, steeplejacks Delta International, and lift operator Alimak.
The stack had to be demolished using hand tools because of its proximity to hazardous nuclear buildings on the Sellafield site.
Workers carried out the task while standing on a three-story platform which clung to the chimney using friction alone. Every time the platform needed to move down, it took an entire day to loosen, readjust, and then reattach the 84 pads that kept it in place. To climb the platform to the top of the tower to start with took 10 months.
The project is part of the 100-year Sellafield decommissioning programme being carried out by Sellafield Ltd on behalf of the Nuclear Decommissioning Authority (NDA.)
John Daniel, construction manager for the project, said: “The team have been working on this project for just over 1,000 days. This was a tough task, which had to factor in the Cumbrian weather. In fact, our plans were impacted by the weather on 300 days. Despite this, the team have delivered the project safely and effectively.
“They have removed over 400 tonnes of concrete and 30 tonnes of steel, while carrying out over 200,000 individual tasks, and 340,000 checks. Strong human performance behaviours have been an important part of this success.”
The climbing platform will now be dismantled. A decision will be taken soon on whether to remove the final few metres of the stack or whether to focus on other priorities and come back to job later.
Because the chimney provided ventilation to other buildings, a new stack had to be built elsewhere on the site and those ventilation lines re-routed. The new chimney – known as the Separation Area Ventilation project – began operating in 2016.
Image: Sellafield Ltd
