Architecture and management of a geological repository - Andra

6 – Overall underground architectureVentilation flows, largely determined by operation and above all construction requirements, may reachor even exceed 500 m 3 /s and are an essential factor in the dimensioning of the undergroundinstallations.6.2 Overall design6.2.1 General organization of the repositoryPackages are isolated in different zones (B, C0, C waste and, if applicable, spent fuel) throughconcern, stated in Section 6.1.1.5, to ensure that different package categories are kept independent ofeach other [37].Figure 6.2.1General organization of the repository6.2.2 Modularity of the repository zonesIn response to the need for compartmentization to ensure long-term safety and the need for modularityin the interests of flexibility and a progressive approach to the construction and operation of therepository, the repository zones are subdivided into a tree structure comprising sub-zones, modules,operating units and cells.The need for a flexible approach to construction and operation has led to the division, depending onthe magnitude of the inventories of C packages and, where applicable, spent fuel, of eachcorresponding repository zone, into 2 to 4 sub-zones, each of which comprises several modules.The modules form the basic elements of repository compartmentization justified by long-term safety.Each zone is thus divided into at least ten modules. 104 .Where operational organization is concerned, the modules can be subdivided into operating units, inwhich only one type of activity is carried out (construction, operation or closure) for a period ofseveral months or years.104 In the case of zones with a small inventory, the number of modules may be less than 10.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM259/495