Above: The Low-Level Waste Repository, near the village of Drigg, in West Cumbria, has been the main disposal site for the UK’s low-level radioactive waste since 1959 Source: Amentum
manage radioactive waste in accordance with the Waste Hierarchy for 14 years.
The importance of capping With a 65-year legacy of receiving low-level radioactive waste, the site is now ready to transition to final disposal, marking a key phase in the repository’s lifecycle. Currently, the focus for the repository site is on Capping Operations. Capping is a key part of the disposal lifecycle and will
provide an engineered protective cover over legacy disposal trenches and vaults, which house low–level radioactive waste – making it ready for final disposal and permanent closure. The end result will be to install an engineered cap of up to 15 metres thick over the legacy trenches and Vaults when they are finally closed. Comprising of multiple layers of different materials, this
‘cap’ will permanently protect people and the environment. Primarily by layering natural aggregates, such as gravel, sand, stones and rocks, as well as engineered materials like geotextile fabrics and bentonite-enriched soil, these multiple layers of material will gradually form a dome-like shape over the trenches and vaults. This will serve as an impermeable barrier above the waste and once complete to anyone passing by will simply look like a small hill, planted and grassed, blending into the adjacent SSSI on the edge of the Lake District fells. From an engineering standpoint, this is quite an
undertaking. When full construction begins, it will involve gradually bringing a large amount of materials to site by rail
using existing rail sidings. This material with then be moved onto the capping site and placed precisely in the various layers needed to build up the protective engineering. It’s vital to be able to build the cap in layers because
each layer will provide a different function. Some will allow gases like methane to escape, others will help form the right shape of the cap, and some will help water drain away. Using natural materials builds confidence in the cap working for longer as evidence obtained over centuries of construction activities has shown that these materials have proven longevity. There will also be a layer to deter human intrusion, made up of large stones. This layer is designed to discourage future generations from digging through the cap, in the event that societal evolution means the understanding of what is under the cap has been lost. Constructing the cap protects the environment and people now and in the future from radioactivity. It will allow us to keep the waste dry and puts in place key requirements from our Environmental Safety Case and fulfils our obligations under the Repository’s Environmental Permit from the Environment Agency (EA). The journey to capping goes back over a decade to the development of the 2011 Environmental Safety Case. Since then, the design of the cap has matured and NWS has obtained planning permission to build it. In addition, NWS has completed a multi-million pound ‘enabling works’ phase (to ensure the Repository site is ready for construction activities), as well as procuring the contract for the first stage of the works.
Above: A location near Threddlethorpe in Lincolnshire is one of three UK sites engaging in the programme to explore hosting a GDF Source: Visit Lincolnshire
www.neimagazine.com | January 2025 | 15
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45
