Experience of an engineering company in shallow land disposal of L/ILW

Technicatome was chosen by the Agence nationale pour la gestion des dechets radioactifs (Andra) as prime contractor for the realization of the Centre de stockage de l'Aube (CSA) near surface radioactive waste disposal facility, which is located in Aube, 200 km east of Paris. This facility has a capacity of 106 m3 and will be able to receive waste over a period of 30 years. The CSA began operation in two stages, the disposal module and container conditioning unit in January 1992 and the drum conditioning unit in January 1993. The objective of the CSA is to provide long term storage for low and intermediate level short lived radioactive wastes by isolating them from the environment. To prevent or delay the migration of radionuclides, intrinsic safety is based on the viability of the two engineered barriers and the natural barrier inherent to the site. The first engineered barrier is the physical and chemical form of the waste in its container. The second is the disposal module, a parallelepipedic concrete structure. The disposal modules are arranged in parallel rows on each part of the storage area. During operation, in order to prevent any contact of rainwater with the waste packages, the disposal module being filled and part of the preceding one are covered by a movable metallic structure. Inside the module, waste packages are embedded in concrete or 'blocked' with gravel. The module is closed by a concrete slab and covered by a waterproof clay cover. Waste passing through the stored wastes and the concrete structure may be collected by a separative water collection system for checking. Depending on their activity, the waste packages may be either blocked, for very low level waste, or embedded in concrete. For conditioning the waste packages received at the CSA, the waste conditioning workshop ensures the compaction of the waste drums and their immobilization by grout, and the embedding of waste metallic containers. (author). 7 figs, 1 tab