Tome Architecture and management of a geological repository - Andra

6 – C waste repository zone• Thermal dimensioning elementsThermally, the distance between cells installed in two neighbouring handling drifts, must besufficiently far apart to avoid any thermal interference that might alter the evolution of a disposal cellin terms of the temperature criterion given earlier.Very close results have emerged from preliminary calculations to test the sensitivity of this distance atvarious foreseeable thermal characteristics for French granites. Thermal interference is at its maximumat the core of the pillar (less than 50 °C) fifty to one hundred years after the temperature peak in thecell [42] for distances approaching twenty metres and interim storage periods of 60-70 years(reference packages C1 and C2) to century-long (reference packages C3 and C4).• Hydraulic dimensioning elementsArchitectural adaptation of the module to the geometry of the host granite block includes a clearancedistance between the excavated openings and the potential water-conducting fractures at the blockboundaries.In principle this clearance distance cannot be predetermined. It essentially depends on the hydrauliccharacteristics of the fractures that delimit each block and their connectivity with the intermediatefracturing admitted in each block. At the current stage, it is considered that all foreseeable situations inthe French context can be covered by clearance distances of several tens of metres (up to one hundred)adapted to suit the type of fractures that set host block limits.6.5.2 Description of a repository moduleThe handling drifts of a module are served by a shared cluster of connecting drifts. The latter aredimensioned to enable successively exploration, construction and package emplacement operationsand finally, when the decision is taken to close the module, backfilling and sealing operations.Figure 6.5.1Schematic representation of a C waste moduleDossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY180/228