UK nuclear waste site set for major upgrade as Graham secures £49.6M deal
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Graham Construction has secured a £49.6 million contract to deliver a critical phase of infrastructure works at the United Kingdom’s Low Level Waste Repository (LLWR) near Drigg, Cumbria. The project represents the most ambitious nuclear infrastructure job awarded to the firm to date and is central to the country’s strategy for long-term radioactive waste containment.
The contract covers the delivery of the Southern Trench Cap Interim Membrane (STIM), a major engineering operation that will see an impermeable capping system installed over a series of historic disposal vaults and trenches. These areas contain legacy low-level radioactive waste, much of it deposited during the early nuclear power era.
The LLWR site, managed by Nuclear Waste Services (NWS), plays a crucial role in the UK’s nuclear decommissioning programme. Since operations began in 1959, the repository has served as the primary location for disposing of low-level waste from nuclear, medical and industrial sources. The STIM project represents a step-change in the UK’s approach to containment, offering a long-term engineered solution that meets modern safety and environmental standards.
First-of-its-kind engineering to cap legacy waste
Nuclear Waste Services has stated that this is the first time the United Kingdom has implemented an engineered cap of this scale and complexity at a radioactive waste repository. The project is intended to provide both physical containment and visible assurance of the site’s long-term stability and safety.
The technical specification involves creating a barrier up to 10 metres thick using compacted clay, geomembranes and soil to seal and stabilise the area. This containment strategy is designed to significantly reduce water infiltration, a key risk factor for waste migration into surrounding land and water systems.
Coordinating rail deliveries and long-term investment
Logistics will be a critical part of the delivery. Earlier this year, the first of approximately 280,000 tonnes of capping aggregate began arriving at the site via rail. Working with Direct Rail Services, NWS has implemented a delivery schedule of up to eight trainloads per week. This heavy freight operation is intended to minimise disruption to local roads and communities while supporting efficient, bulk delivery of essential materials.
Looking ahead, Nuclear Waste Services has issued further procurement notices for follow-on works including vault optimisation and additional engineered capping for Vault 8 and other parts of the site. These activities form part of a longer-term strategy to manage the UK’s radioactive waste, which could span over a century.
For Graham, the project reinforces its growing role in high-integrity infrastructure delivery across complex and highly regulated environments. Within the broader UK nuclear sector, it reflects meaningful progress in transitioning legacy disposal sites towards safer and more permanent closure.