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Sellafield decommissioning reaches new heights

14 November 2017

The demolition of one of Sellafield’s tallest hazards has started.

A chimney on top of the oldest reprocessing plant on the nuclear site, will be crunched away at a rate of 1 metre a week.

The tower will be gone by 2020, resulting in a permanent change to the Sellafield skyline.

The stack sits on top of the First Generation Reprocessing Plant and provided ventilation to a fleet of reprocessing plants.

The 60 year old structure no longer meets modern construction standards, therefore must be removed as a priority.

At 61 metres tall, on top of a 61 metre building, it was the tallest structure on the site, until a modern replacement was built.

It’s position on one of the most congested nuclear sites in the world has made this a complicated and lengthy process.

Conventional demolition techniques like explosives and cranes can not be used in such a crowded, hazardous environment.

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 we 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.”

Sellafied Ltd has worked with principal contractors, Nuvia Ltd and steeplejacks, Delta International; who have brought specialist demolition expertise and innovative ideas to the project.

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

A self-climbing platform has been designed, engineered and installed to act as a podium so that workers can safely access the 650 tonne chimney.

Using hand held tools like drills, hydraulic breakers, concrete crunching jaws and plasma steel cutting torches, workers will remove each piece of concrete and steel from the stack by hand to a waiting waste skip.

The demolition started in October, with workers accessing it from the circular platform, which is held in place by friction, and moves up and down the barrel of the stack.

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.”

Ends

Notes to Editors

  • The chimney stack was built in the 1950s and is the separation area’s main ventilation discharge facility, serving many different plants and buildings in a congested area of the Sellafield site.
  • At 61m tall, atop a 61m building, the stack was the tallest building on the site until the building of the replacement ventilation stack.
  • The stack tapers from 6.1m diameter at bottom to 4.63m at its narrowest point. The tapered design was an important consideration when developing the self-climbing platform.
  • The concrete wall varies in thickness from 0.53m down to 0.15m.
  • The stack wasn’t built to modern day safety standards, and this, combined with its location at the heart of the Sellafield site, means that it needs to be removed.
  • The project to do this is one of the highest priorities for our regulators, and as such, progress is reported to the government on a regular basis.
  • As the stack is a crucial outlet for discharges, we had to build a replacement ventilation and discharge system before we could consider removing a single crumb of concrete.

For more information, please contact:

Ruth Hutchison: +44 (0)19467 86227  ruth.hutchison@sellafieldsites.com