Tome Architecture and management of a geological repository - Andra

7 - Spent fuel repository zoneA single package per borehole is envisaged given the foreseeable dimensions of the spent fuel disposalpackages. Furthermore limiting borehole capacity to a single package will also simplify control of celland module alteration (primarily thermal). Thus the option proposed is a borehole with a limitedlength of about 8 metres, and a diameter of less than 2 metres, to enable a clay engineered barrier to beplaced between the disposal package and the rock.7.2.1.2 Installing disposal modules in "blocks" of granite away from water-conductingfaultsThe spent fuel disposal modules, like the C waste modules, are installed in the granite away from thefaults usually of several hundreds metres in dimension; such faults are too water-conducting (Figure7.2.2) to be intersected by module drifts and in particular by handling drifts. This principle, leads tomodule separation in the repository zone architecture according to granite massif fracturing. Theadaptation of the architecture to this fracturing is once again based on the definition of criteria relatedto the properties of these faults and their on-going characterisation (cf. § 4.3.1).Figure 7.2.2Principle of the arrangement of a spent fuel disposal moduleDossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY200/228