THE DECONTAMINATION AND DECOMMISSIONING OF THE GRAPHITESILOS AT VANDELLóS

摘要

The 500 MWe gas graphite reactor Vandellos 1 is being decommissioned to a Stage 2 status. The Stage 2 in this particular case involves the dismantling of almost all structures and components outside the reactor vessel. The vessel itself will remain, after removal of fuel, with its internals, until the end of the dormancy period. By achieving Stage 2, about 80% of the site will be released. During the operation of the plant, the graphite fuel sleeves were stored in three concrete silos on site which included about 1000 tonnes of graphite and activated metal pieces. ENRESA started the decommissioning of the graphite silos in 2000. Decommissioning involves the dismantling and removal of equipment from each cell, the decontamination for the cell walls, ceilings and floors and the dismantling of the ventilation system. These activities were followed by a complete radiological monitoring in order to obtain the release of the remaining structures and proceed with its demolition. This paper provides an overview of the decontamination and decommissioning activities related to the graphite silos at Vandellos 1 and describes the efforts made to improve safety through the use of innovative technologies. In addition, the strategy to be followed for the safe management of the graphite waste is also described.