Tallest historic chimney at Sellafield to be demolished

sellafield logoThe skyline at Europe’s oldest nuclear site will change forever when the 122 metre structure is removed.
The 61-metre chimney sits on top of an eleven-storey reprocessing plant and stands 122 metres from the ground in total, making it the tallest historic structure on the site since it was built in the 1950s – but not for much longer.
Sellafield Ltd’s demolition team is developing plans to safely dismantle it but, because of the location of the chimney right at the heart of one of the busiest areas of the most complex nuclear site in Europe, they’ll not be able to use explosives to bring it down.
Instead they’ll be using a special platform to remove the 600 tonnes of concrete and rebar, and over 25 tonnes of stainless steel that make up the huge structure.
Project manager Matthew Hodgson said: “The job of bringing down the stack is going to be a delicate operation to ensure 100 per cent safety of all personnel and surrounding nuclear plants.  We have employed Nuvia Limited who has been working with us and a number of other contractors, including Delta Steeplejacks, for the last three years on the demolition scheme.
“Obviously conventional demolition using explosives is not feasible therefore we will use an ingenious self-climbing platform which will bring the chimney down bit by bit in a controlled manner.”
This clever technique has recently been used in the demolition of the Battersea Power Station’s famous chimneys, which have actually then been re-built to preserve the appearance of the capital’s iconic building.  
Matthew added: “A mini-replica of the tapered chimney will be built to test the methodology as the diameter of the chimney increases the lower you go down, so the platform will correspondingly have to increase in size.  A specialist diamond wire cutting system will be used to remove large sections of the concrete structure and the internal metal flue, all of which will have to be lowered to the base of the stack for monitoring before disposal.”
Steve Slater, Head of Decommissioning said: “Demolishing this chimney will represent a very visual demonstration of our commitment to tackling one of the most guarded parts of Sellafield’s legacy.
“The plant was built in the shadow of the war to secretly produce nuclear materials for the UK’s defence programme.  It reprocessed fuel from the pile reactors and was then later used for commercial fuel reprocessing before the Thorp reprocessing plant took over.
“It’s going to be out with the old and in with the new, with the new Separation Area Ventilation (SAV) stack taking over. Work to construct that new replacement stack is continuing.”
Recent assessments of the 1950s stack have confirmed that it doesn’t meet modern design standards and its removal is considered a high priority for Sellafield Ltd, the Nuclear Decommissioning Authority and the Office for Nuclear Regulation (ONR).
Work on site will soon begin to install an industrial lift and a roof bridge structure, allowing access to the base of the chimney. The lift and bridge will then be used for the removal of waste materials when demolition starts.
The demolition will take several years to complete.

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