All that now remains of the first generation reprocessing plant stack is a nine-metre stub.
The 61-metre high stack had to be demolished by hand because of its proximity to hazardous nuclear buildings on the Sellafield power station site.
Instead of using explosives or big machinery, workers had to cut away the concrete and steel stack using only hand tools. And they did it while standing on a platform which clung to the chimney using friction alone.
It took 10 months for the platform to inch its way to the peak to enable demolition work to start. It began its 61-metre ascent in November 2016 and arrived nine months later in August 2017.
Demolition work started in October 2017. 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.
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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.)
It is a collaboration between Sellafield Ltd, demolition partner Nuvia, steeplejack Delta International, and lift operator Alimak. Another dozen or so companies also provided specialist skills and equipment.
Construction manager John Daniel 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.”
Having done its job, the Alimak 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.
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