The turbine hall and adjoining structures at the UK’s Sizewell NPP has been successfully demolished, Nuclear Restoration Services (NRS) announced. An area the size of a football pitch has been cleared ready for its next use, “creating a huge skyline change for the Suffolk coast”, NRS said.
Sizewell A’s two 210 MWe Magnox gas-cooled reactors operated from 1966 until 2006. Defueling began in 2009, and the fuel was placed in the site’s used fuel storage ponds before being packaged in transport containers for shipment to the Sellafield site in Cumbria for reprocessing. The last flask of fuel was shipped to Sellafield in August 2014, and the plant was declared completely fuel free in February 2015. This marked the removal of 99% of the radioactive hazard from the plant site. Planning consent was given to demolish the turbine hall and electrical annexe in August 2024. The Sizewell A site is expected to be completely cleared by 2077.
“This is an incredible achievement for NRS, our contract partners Erith, the Office for Nuclear Regulation (ONR) and the Nuclear Decommissioning Authority (NDA),” said Alan Walker, Sizewell A Site Director. “I would like to thank everyone including those involved and our neighbours for their continued support throughout, as well as the ONR for enabling us to push the boundaries of innovation in conventional demolition together. The learning from this will be applied to other NRS projects to continue delivering efficient, value for money decommissioning and restoration of nuclear sites.”
The project demonstrated technical innovation and set a new benchmark for the largest use of explosives on a UK nuclear site and the longest programmed detonation sequence in Europe, NRS noted. These were used to weaken the four gigantic concrete plinths that supported two 650-tonne turbogenerators. The use of explosives reduced the project schedule by four months, costs by £300,000 ($406,275) and minimised vibrations to negligible levels compared with the use of traditional mechanical percussion removal techniques. Some 40 tonnes of CO2 emissions were also avoided by minimising machinery fuel use.
The plinths were reduced to rubble paving the way for full clearance of the turbine hall basement and arrival of the high reach excavators to dismantle the structure. Two 90-tonne safe working load cranes, each weighing 65 tonnes, were removed from their rails onto a landing pad ready for metal recycling.
More than 17,000 tonnes of concrete and rubble were removed from the turbine hall, fire station and electrical annexe structures. This waste was processed through a mobile crusher to reduce its size to a specification that enabled it to be exported and re-used.
A scrap metal contract has raised over £3m to date from the sale of the 11,000 tonnes removed during the de-plant and demolition phases. This revenue will be used to offset decommissioning costs. The project achieved a 95% recovery rate for construction and demolition waste, much higher than recent industrial averages.
“The successful demolition of the turbine hall brings skyline change to the Sizewell A site. The innovative use of explosives provides valuable learning for future decommissioning activities, and the segregation and reuse of demolition material supports the NDA’s sustainability targets,” said David Rushton, NDA Programme Manager.
“We’ve worked very closely with NRS, adopting an enabling stance to allow the licensee to push forward with a modern, and at times, ground-breaking approach to accelerating this major dismantling project,” noted Andrew Bull, ONR’s Nominated Site Inspector at Sizewell. “ONR works hard to reduce unnecessary regulatory burden and add value. This has been no better demonstrated than for the removal of the Sizewell A turbine hall, where we have played a key role in this example of decommissioning the UK’s nuclear estate.”
