Preparations begin for capping UK repository

Monday, 12 August 2024

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. It will also include placing other construction materials to progress towards the final cap.

It will provide an engineered protective cover - comprising of layers of material - over the waste that has been disposed of in the trenches and vaults to permanently protect people and the environment.

Civil engineering firm Graham Construction has been awarded a four-year contract and will start work on the membrane this month, with major works commencing in February 2025.

NWS - a subsidiary of the Nuclear Decommissioning Authority - said it 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.

The contract for the rest of the work for the 10-metre thick cap will come later, 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," said NWS Repository Site Programmes Director Jonathan Evans. "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."

Graham Contracts Director Alastair Lewis added: "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."

The LLWR site has operated safely since 1959. Its role is to ensure that low-level waste generated in the UK is disposed of in a way that protects people and the environment. The repository site receives low-level solid waste from a range of customers, such as the nuclear industry, the Ministry of Defence, non-nuclear industries, educational, medical and research establishments.