Sellafield decommissioning fells tower

With the decommissioning of Sellafield well underway, the works have progressed to the demolition of its tallest hazard.

The chimney tower, which sits on top of the First Generation Reprocessing Plant, is being removed at a rate of one metre per week. When the final piece is removed in 2020, it will mark a permanent change to the Sellafield skyline.

As part of the oldest reprocessing plant on the nuclear site, the provided ventilation to a fleet of reprocessing plants. Now 60 years old, the structure no longer meets modern construction standards, and therefore must be removed as a priority. Sitting at 61m tall, on top of a 61m building, it was the tallest structure on the site, until a modern replacement was built.

Even with the added challenges of decommissioning a nuclear site, the location of the chimney in the heart of the site presents a series of unique hazards, making this a complicated and lengthy process. The crowded and hazardous environment has made conventional demolition techniques such as explosives and cranes impossible to use.

Sellafield Ltd brought on board two specialist companies to help develop innovative solutions to the problem; Nuvia Ltd and Delta International. They developed a self-climbing platform to act as a podium, giving workers safe access to the 650 tonne chimney, the circular platform is held in place by friction and moves up and down the stack.

This work saw Nuvia win the Technology Innovation Implementation award at the 2017 NDA Estate Supply Chain Awards.

Stuart Latham is head of remediation at Sellafield Ltd, he 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.

“Safety is the number one priority, so thorough testing has helped us ensure everything works as it should.”

Mina Golshan, Director of ONR’s Sellafield, Decommissioning, Fuel and Waste Division, said: “Starting demolition of this redundant stack is a key achievement by Sellafield and another important step towards reducing the risk and hazard posed by legacy facilities on site in order to further enhance safety. This is the focus of our regulatory strategy for the site.

“Our inspectors have engaged with Sellafield Ltd during the design, build, testing and commissioning phases and gathered evidence that assured us of the suitability of the proposed demolition activity and Sellafield’s supporting safety case.”

 

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