Tome Architecture and management of a geological repository - Andra

5 – B waste repository zoneOn the access drift side, the shielded cask (that delivers each disposal package from the surfaceinstallations) docks at the first gate. This gate protects the operators working in the access drift fromradiation.The dual-gate system is fitted with a mobile travelling floor and a rotary table to enable the fork-lift truckto retrieve the disposal package out of the cask and move it into the disposal chamber (see section 5.6.3).The sliding door on the disposal chamber side allows this fork-lift truck through to place the packages inthe disposal tunnel.The space between the system’s two gates is about ten metres long – enough to park the fork-lift truckduring maintenance operations (the sliding door thus offers radiological protection for the maintenancestaff).The cell head accommodates the drainage water collection and pumping installation either under theslab or in a side recess.Ventilation in the dual-gate system zone is provided firstly by ducts linked to the disposal tunnelreturn air pipes, and secondly by shielded twists & turns at the gates.Figure 5.4.2Cell head5.4.1.3 The access driftThe access drift links the module connecting drifts to the cell head. Its useful section, approximately30m 2 , enables the tunnel construction machinery and then the package transfer cask trolley to accessthe disposal chamber.The entrance drift length is adapted so that a seal can be constructed in a zone that is slightly damagedor undamaged by the excavations works. This zone is located some ten metres from the connectingdrift and the cell head. The access drifts are designed to be about forty metres long.Dossier 2005 Granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY130/228