United Kingdom: Development of the Drigg LLW disposal site

British Nuclear Fuels plc (BNFL) owns and operates the Drigg disposal site, which is the UK's principal facility for the disposal of low level radioactive waste. This section describes the development of the Drigg site to date, in particular the upgrading of the site in the late 1980s and early 1990s, which centred around the phasing out of disposal into trenches and the introduction of a revised waste form and disposal into engineered vaults. The Drigg site is located on the West Cumbrian coast about 0.5 km inland and some 6 km to the southeast of the Sellafield site. The site was originally developed in 1939 as a Royal ordnance factory and some of the surface features date from this period. Ownership of the site subsequently passed to the Atomic Energy Authority, which was granted planning consent in 1957 for the disposal of LLW in the northern 40 ha of the site, referred to as the 'consented area'. In 1987 a major upgrade of disposal operations at the Drigg site commenced with the principal aims of improving waste management practices and the efficiency of space utilization, and enhancing the visual impact of disposal operations. This article first describes the interim cap and cut-off wall associated with the trenches and the upgrade to the leachate management system. The basis for the revised disposal strategy and associated waste form of high force compacted, containerized and grouted waste is then discussed, followed by a description of vault 8. The upgrading to the new waste form of some of the wastes initially placed in vault 8 and the retrieval of the PCM wastes currently stored at the Drigg site are then briefly discussed. Development has taken place from tipping of wastes into trenches to the orderly emplacement of compacted, containerized and grouted wastes in engineered vaults. Future operational facilities will consist of a series of vaults within the consented area. In the longer term, engineering measures associated with the eventual closure of the site are planned to include a final cap, groundwater cutoff wall and vertical drain. The plans for site development will be regularly updated to reflect both operational developments at the site and engineering and scientific developments and understanding. Engineering design work will be used to assess and optimize potential alternative development plans. These plans will continue to be discussed with regulatory authorities and other stakeholders