The first two of as many as six underground low-level radwaste stores have been handed over to Dounreay parent body, Cavendish Dounreay Partnership.
Graham Construction excavated a total of 243,000 cubic metres of rock during construction of the two vaults. Each vault is equivalent in volume to between 370 and 450 double-decker buses, with the floor 11 metres underground. A total of 7,600 cubic metres of concrete, 1,330 tonnes of reinforcement and 260 tonnes of structural steel were used during their construction.
Each underground vault has been designed to take low-activity waste. The waste is generated during the clean-out and dismantling of nuclear reactors, reprocessing plant and other radioactive facilities at the site. It is currently stored in containers on the site.
Low-active waste created during the operation of the site was disposed of in a series of shallow pits, until they became full in the 1990s. The site consulted in 2003 on what should happen to up to 175,000 cubic metres of low-active waste expected to arise during the decommissioning phase. Planning permission was granted in 2009 for up to six underground vaults adjacent to the eastern perimeter of the site, capable of taking the existing and future arisings of low-active waste as more of the site is decommissioned.
Subject to regulatory and other consents, the first containers of waste are due to be moved off the Dounreay site later this year, filled with grout and placed in the vaults. Once each vault is full, it will be back-filled with grout to create a monolithic block.
Photo: Ceremony marking the hand-over of LLW stores at Dounreay