Work starts on capping radioactive waste trenches in Cumbria

Nuclear Waste Services (NWS), the organisation responsible for the UK's low-level radioactive waste disposal, is undertaking this crucial task as part of the final capping process for the now full and permanently closing legacy disposal trenches and vaults.

The focus of this phase is the Southern Trench Cap Interim Membrane (STIM), which involves laying a protective membrane up to 10m thick over the disposal trenches.

This membrane is composed of layers of materials that will safeguard the waste disposed of in the trenches and vaults.

GRAHAM Construction has been contracted for four years to carry out this work. Some of the work will start this month, with major operations starting in February 2025.

The planned capping diagram (Image: Nuclear Waste Services UK)

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.

"We are very pleased the initial work is progressing and we can move forward with this key phase, working collaboratively with GRAHAM Construction."

He added that the capping is essential to NWS’s mission to make the UK’s nuclear waste 'permanently safe, sooner.'

Alongside the capping, NWS has also completed the design for the final cap, the rail transport arrangements, and the extensive enabling works necessary for procuring, importing, and emplacing thousands of tonnes of materials.

Alastair Lewis, GRAHAM Construction's contracts director, said: "This is the largest nuclear project to date for the business.

"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."

NWS has committed to keeping the community informed about the project through drop-in sessions and site tours.

Martin Walkingshaw, chief operating officer at NWS, said: "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."

He added that plans are in place to minimise any associated noise, dust, traffic, ecological, and visual impacts.

The repository site near Drigg in West Cumbria began accepting low-level radioactive waste in 1959.

Disposal methods evolved in the late 1980s and early 1990s, leading to the construction of highly engineered concrete vaults.

These were part of a modern, innovative approach to the treatment and safe disposal of low-level nuclear waste in specially designed metal containers.

These containers were placed in the engineered vaults at the repository.

NWS is part of the NDA group, which oversees the safety and security of the UK’s former nuclear sites and facilities as they are decommissioned.

The UK has been producing and managing nuclear waste for many decades and will continue to do so for many more.

The UK Government views nuclear power as essential to the low-carbon energy mix and securing energy supplies in the future.