Tome Architecture and management of a geological repository - Andra
Tome Architecture and management of a geological repository - Andra
Tome Architecture and management of a geological repository - Andra
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7 - Spent fuel <strong>repository</strong> zone7.6 Disposal process as part <strong>of</strong> the reversibility rationale7.6.1 Characterisation <strong>of</strong> the granite blocks <strong>and</strong> construction <strong>of</strong> the modulesThe same host block exploration <strong>and</strong> module construction methods are used as for vitrified C waste<strong>repository</strong> structures given the close similarities between them <strong>and</strong> spent fuel <strong>repository</strong> structures.Exploration relies on drift <strong>and</strong> borehole work. Modules are constructed using blasting techniques <strong>and</strong>drifts using drilling techniques with a micro-tunnel boring machine adapted to vertical operation (seechapters 6.6.1 - 6.6.4).7.6.2 Operation <strong>of</strong> a cell as part <strong>of</strong> the reversibility rationaleThe equipment design <strong>and</strong> spent fuel cell emplacement process have been transposed from SKBdemonstration carried out in the Äspö laboratory [56].7.6.2.1 Description <strong>of</strong> the transfer <strong>and</strong> cell emplacement equipment• The transfer caskThe spent fuel transfer cask comprises a cylindrical shielded vessel ("steel <strong>and</strong> neutron-absorbingmaterial"), with walls about 200 mm thick. It is made up <strong>of</strong> two parts that are screwed together for thetime <strong>of</strong> transport [57].The upper part (on the right <strong>of</strong> Figure 7.6.1) is fitted with a grapnel to grip the disposal package. Thedimensions <strong>of</strong> the transfer cask are about 6 m long, a diameter <strong>of</strong> about 1.70 m with an unloaded mass<strong>of</strong> about 30 tonnes <strong>and</strong> 75 tonnes when loaded.Figure 7.6.1Radiological protection cask for CU packages• The transfer vehicleTransfer <strong>of</strong> the cask from the surface installations to the underground installations is carried out usingexactly the same approach as described earlier for B <strong>and</strong> C waste. Once the transfer cask is at the<strong>repository</strong> level, it is placed on a transfer vehicle that carries it to the emplacement equipment locatednear the host cell.The vehicle is fitted with independent multi-directional wheels giving a very tight turning circle. Thevehicle’s onboard mechanical equipment enables the transfer cask to be pulled or pushed horizontallyDossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY214/228
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