The disposal of low level radioactive waste at the Repository began in 1959 with waste being placed in lined trenches at the site, which is located near the village of Drigg in West Cumbria. Disposal techniques evolved during the late 1980s and early 1990s which resulted in the construction of highly engineered concrete vaults for future disposals. This resulted in a more modern approach to the treatment and safe disposal of low level nuclear waste in specially designed metal containers, which were placed in the engineered vaults at the Repository.
Nuclear Waste Services (NWS), which manages the disposal of the UK’s low level radioactive waste, is carrying out work on the final capping of legacy disposal trenches and vaults which are now ready for permanent closure.
Capping is a key part of the disposal lifecycle and work is now starting on the Southern Trench Cap Interim Membrane (STIM) which will involve placing a new membrane, or 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.
It will provide an engineered protective cover over the waste that has been disposed of in the trenches and vaults. Comprising of layers of material to permanently protect people and the environment.
Civil Engineering firm Graham Construction has been awarded a four year contract and will start work this month, with major works commencing in February 2025.
Alongside this, NWS has also completed the design of the final cap, the 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.
Jonathan Evans, repository site programmes director at 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. We are very pleased the initial work is progressing and we can move forward with this key phase, working collaboratively with Graham Construction.
“It is important that NWS caps the existing vaults and trenches to provide long-term protection of the environment for generations to come. This work is integral to our mission, to make the UK’s nuclear waste permanently safe, sooner.”
Alastair Lewis, Graham contracts director said: "This is the largest nuclear project to date for the business and will continue on from previous works undertaken during the LLWR Scheme.
We recognise the critical importance of this work in ensuring the long-term environmental protection provided by the Repository and are fully committed to delivering a high-quality solution in partnership with NWS.”
Martin Walkingshaw, chief operating officer at NWS, added: “NWS has been and will continue to engage with the local community with drop-in sessions and site tours to share more details about what residents will see and hear during these works. Plans are in place to mitigate and minimise any associated noise, dust, traffic, ecological and visual impacts in line with planning conditions. For example, through the installation of noise barriers and visual screening walls, regular noise monitoring of activities and a commitment to bring the majority of materials to the site via rail. NWS will continue its commitment to proactively engage the local community.”