The explosive demolition was undertaken by Precision Demolition Company Ltd, which deployed the largest single use of electronic detonators and cartridge explosive ever used on a licensed UK nuclear site.
Main demolition contractor is Erith, working for Nuclear Restoration Services (NRS – formerly Magnox).
More than 1,200 holes were drilled into the plinth structures that bore the weight of two 605-tonne turbo generator units. The charges were then set and the plinths wrapped ready for detonation.
This method reduced the need for heavy machinery – saving time and money and reducing noise and dust. It means the turbine bases can now be completely razed to the ground using machinery within just two weeks, instead of deploying older and slower methods of drilling the structure apart which would have taken several months.
A series of test blasts were undertaken and the detonator timing sequence was specifically designed to meet stringent nuclear site requirements for air overpressure and ground vibration.
More than 7,100 tonnes of metal have been removed for recycling; more than 17,000 tonnes of demolition rubble will also be re-used and recycled.
An area the size of a football pitch will be available for future decommissioning use by NRS in or around March 2025.
The method, which saved time and money and reduced a prolonged period of noise and dust pollution, required special approval from the Office for Nuclear Regulation (ONR).
Sizewell A site director Alan Walker said: “It’s fantastic to see Nuclear Restoration Services (NRS), our contract partners and the Office for Nuclear Regulation pushing the boundaries of innovation in de-plant and conventional demolition together.
“The detailed planning and stakeholder engagement for this were exemplary. Everyone involved has done an outstanding job and this success demonstrates our commitment to achieving safe, efficient decommissioning processes.”
Andrew Bull, ONR’s nominated site inspector at Sizewell A, said: “This was a great example of joint working between regulator and dutyholder and everybody being open to considering and actioning novel and forward-thinking technological solutions to bring about efficiencies.
“ONR’s stance as a consistently enabling regulator means that we will always support proactive and innovative methods of working provided these are conducted safely and securely.”
NRS awarded Erith the contract in 2023 for the hazard removal, soft strip, de-plant, and demolition of the turbine hall complex, including associated cable tunnels and support structures. Operating under an NEC Option C target cost contract as the principal contractor, it is tasked with demolishing and clearing the site of all structures down to the top of the lowest ground-bearing slab.
Alan Cumming, chief assurance and performance officer at the Nuclear Decommissioning Authority, visited the site this week to see the progress. He said: “This is what mission delivery is all about. Decommissioning, knocking stuff down and dispatching the waste. It’s an incredible achievement and testament to the expertise, capability and innovative mindset each partner brought to the project.
“It showcases the power of collaboration and our capability as a sector to deliver groundbreaking progress, while still maintaining the most rigorous safety standards, paving the way for future advancements.
“This is a substantial step towards completion of the safe, secure and sustainable decommissioning of Sizewell A, leaving a positive legacy for the community and future generations.”
