Nuclear Waste Services (NWS) has begun final capping of UK legacy disposal trenches and vaults at Drigg in Cumbria, which are now full and ready for permanent closure.
A key part of the disposal lifecycle, work is now starting on the Southern Trench Cap Interim Membrane (STIM) which will involve placing a membrane protective layer over the legacy disposal trenches up to 10m thick. It will also include placing other construction materials to progress towards the final cap.
The STIM will provide an engineered protective cover over the waste. Civil Engineering firm GRAHAM Construction, has been awarded a four year contract by NWS, which manages the disposal of the UK’s low level radioactive waste, and will start work this month, with major works commencing in February 2025.
NWS has also completed the design of the final cap, the extensive enabling works and the rail transport arrangements that are necessary for procuring, importing and emplacing thousands of tonnes of materials, whilst complying with the conditions imposed by the Planning Authority.
A key enabler of the project is having sufficient rail transport arrangements in place to move and emplace the thousands of tonnes of materials. NWS is working with Nuclear Transport Solutions (NTS), another subsidiary of the Nuclear Decommissioning Authority (NDA), to manage this process.
Commenting on the progress, Jonathan Evans, Repository Site Programmes Director, NWS, said: “Placing the engineered cap over the legacy radioactive waste disposal facilities at the UK’s Low Level Waste Repository (LLWR) is a first of its kind activity for the UK. The capping work is fully integrated with our ongoing disposal operations at the site.” He continued: “It is important that NWS caps the existing vaults and trenches to provide long-term protection of the environment for generations to come.”
Disposal of low-level radioactive waste at Drigg began in 1959 with waste being placed in lined trenches at the site. Disposal techniques evolved during the late 1980s and early 1990s which resulted in specially designed metal containers, which were placed in the engineered vaults at the repository.
