De-planting of four boiler houses at the Bradwell site in the UK was achieved below cost and ahead of schedule thanks to award-winning supply chain collaboration.
Bradwell is on target to enter the "care and maintenance" decommissioning phase – safe to be left passive for decades before the final clearance – by the end of 2015.
The decommissioning work has involved de-planting and weather-proofing the boiler houses, including the safe removal of asbestos.
Industrial services and access were provided by Deborah Services (DSL). David Hannon, DSL site manager for Bradwell, says: "We managed to deliver a two-and-a-half year programme a month ahead of schedule and seven per cent below target cost, as well as with no lost time accidents in more than 250,000 working hours."
DSL cut time and costs by using training, workshops and best practice taken from other sites and sectors to help de-plant four boiler houses at the site. Risk assessments, method statements for each element, a permit management plan and an integration schedule were all in place before the work started, while daily project planning meetings served to share information.
This combined delivery approach enabled problems to be solved more quickly. For example, instead of full access scaffolding, DSL used quickly deployed mobile towers and mobile elevated working platforms where practicable.
Steve Woolley was the special projects manager for DSL for four Magnox sites at Bradwell, Oldbury, Sizewell and Berkeley. He explains: "The risk/reward basis of our contract means we are penalised if we miss key performance indicators and rewarded should we save time or money.
“The fourth boiler house was delivered at 10% less cost and 30% faster than the first boiler house."
A ‘clean – create access – de-plant – remove access – clean’ process was put in place at Bradwell, where 400t of scaffolding was used to prepare the two 200ft high boiler houses in readiness for asbestos removal and access works for de-planting.
Detecting asbestos is difficult. It is not visible and has no chemical fingerprint but is harmful whether alone or in a mixture with other materials. The air was continually monitored and analysed, especially during the opening of previously sealed areas. Every team member was trained to work in an asbestos environment, and asbestos removal team members were trained in the use of mobile access towers.
Asbestos-bearing materials were removed by wetting, injection, spraying and controlled dry stripping. Using a ‘wrap and cut’ method, DSL was able to remove larger components – wetting the material and then wrapping it in polyethylene sheets before cutting it and removing it from site. Pipework, cabling and ducting were all suitable for ‘wrap and cut’ and handled more safely at the disposal site.
Size, weight and exit routes were all factored into the planning, in addition to transport.
“Your first priority is setting the job up right from the start, so you get the right equipment on site such as workwear and shower units. You ensure the showers are as near to the site as possible so the potential for contamination is minimised," says Woolley. "The team is briefed as to exactly how, where, when and who’s going to pull out what asbestos, because different types of asbestos call for different techniques."
Woolley adds: "At Sizewell,…by questioning the need to remove pipes and asbestos separately…we saved many hours by disposing of pipes with asbestos intact.
To the best of our knowledge, no one’s ever done it before in the nuclear environment. To transfer other industrial applications into our work with Magnox takes significant planning, preparation and management."
Steve Lock, head of framework contracts for all Magnox sites, says, "We refer to [DSL] as ‘access and insulation’ rather than ‘scaffolding and asbestos removal contractors’. That’s because they’ll often suggest a different way of doing things. So instead of erecting tonnes of scaffolding, they’ll often use rope or powered access to get a job done. The same site operatives are trained in other disciplines to enable multi-tasking so DSL can help us react quickly to changes in programmes.
“We’re no access experts. We tell DSL what we want and then they interpret what that means for what they’re doing and come back with what we need."
DSL’s David Hannon adds, "When decommissioning a site, the key is establishing rigorous working practice. But…the work means you spend most of your time adapting those practices as the project evolves…[It] can challenge your resourcing levels."
He says projects require a combination of meticulous planning and conscientious communication. For instance, the sheer logistics of bringing 4000 tonnes of scaffolding on to site requires scheduling so that you can store it appropriately.
Lessons learned at Bradwell have been used at Oldbury, Berkeley and Sizewell. Now DSL is also developing an integrated service delivery model, incorporating: site rescue systems for incidents at height and in confined spaces; inspections in potentially contaminated zones; and project management to maximise supply chain effectiveness.
The UK’s Nuclear Decommissioning Authority named the Doosan Keltbray consortium at Bradwell ‘Best example of supply chain collaboration led by a large company’ in 2013