This week, the Nuclear Decommissioning Authority announced the completion of two major decommissioning projects. The last drums of Magnox Depleted Uranium (MDU) have been removed from Chapelcross site and a project to remove asbestos cladding from Calder Hall has ended.
Chapelcross saw the culmination of a GBP 6.5 million project when the last of more than 10,000 drums of MDU left the site. The 5000t of material, a product of reprocessing used Magnox nuclear fuel at Sellafield, was placed in interim storage at Chapelcross during the 1970s and 1980s.
A project to transfer the MDU from standard oil drums to modern stainless steel overpacks and transport them to Capenhurst began in 2005.
The NDA’s programme director for Magnox, Sara Johnston, said: “The transfer of MDU from Chapelcross addresses one of the major hazards that the NDA identified when it was established five years ago.”
Dave Wilson, Site Director at Chapelcross, said: “By ‘overpacking’ the MDU and transporting it to a specifically designed store at Capenhurst, we have removed many of the hazards associated with this material – this is great news and it marks a huge step towards decommissioning Chapelcross Site. This may not be as high profile as the demolition of the cooling towers, or removing asbestos from the heat exchangers, but it has been a major project and we're delighted to be able to complete it on behalf of our customer, the NDA.”
At Calder Hall, a GBP26 million project to strip out 2300t of asbestos cladding from heat exchangers, turbine halls and associated plant also came to an end. The project involved over one million man-hours of work and was completed on time and with a saving of over GBP 1 million on the estimated costs.
Ian Hudson, the NDA’s programme director for Sellafield site facing team said: “This is an excellent achievement for the Calder Hall team. The asbestos removal is a major step forward in the overall decommissioning programme and the success of this project demonstrates how hazards can be effectively reduced through well managed, safe operations.”
After Calder Hall ceased electricity production in 2003, a method of safely removing the asbestos in line with strict regulations was piloted and a contractor engaged.
One of the main challenges during the project was that much of the work had to be carried out at height. Scaffold towers over 36m tall had to be built around the sixteen heat exchangers on the outside of the reactors. These formed the structure for asbestos tents, which prevented the release of asbestos and ensured ventilation for the workers. Around 100 individuals worked in arduous and confined conditions during the project, but at no time were any workers exposed to asbestos.
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