Architecture and management of a geological repository - Andra

5 – Repository ModulesSome foreign concepts mentioned above include filling in spaces, whilst others, like Andra's, favourminimizing such spaces through a suitable choice of disposal cell geometry and means ofmaintenance.5.1.3 Description and dimensioning of the cell and access driftThis section is devoted to describing the cell and its equipment in operating configuration, togetherwith the access drift. It also sets out the main results of the mechanical dimensioning calculations andshows how considerations relating to the integrity of the geological medium, the physical andchemical environment of the packages, the emplacement of the packages and the safety of therepository are taken into account in the choice of materials and design [61].5.1.3.1 Overall characteristicsThe description of the design principles of the B waste disposal cell given previously highlighted theexistence of three parts:- the useful part (or body) containing the disposal packages,- the head, which is dedicated to extracting the packages from their transfer transfer cask and to theradiological protection of personnel during repository emplacement operations 64 ,- the access drift where the cell seal will be placed.The useful part comprises three main elements (Figure 5.1.11). The ground support and lining 65 ensurethe stability of the cell. The slab and its equipment enable the transporter to move and take up theweight of the packages. Finally, the tubes set in the top part of the lining are used for ventilating thecell.The cell’s dead end consists of a tympanum and a porous wall for ventilation. The cell head isequipped with an airlock for the transfer of packages between the radiological protection transfer casksand the irradiating cell body inaccessible to personnel.Figure 5.1.11B cell in operation64Except for cells containing less irradiating packages, which do not need an airlock.65 The ground support, fitted as the excavation progresses, ensures the stability of the excavation during the construction work. The purposeof the lining is to maintain this stability over a long period (several centuries)DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM172/495