Tome Architecture and management of a geological repository - Andra

7 - Spent fuel repository zoneTable 7.4.1Functional axial dimensions of disposal cellsComponent Description CU2Cell head backfillingHeight of the backfill inthe disposal boreholeCU1"Short" "Long""Court" "Long"1 mCell plug Plug thickness 1.5 mDisposal package Total length 4.5 m 4.5 m 5.25 mEB at the baseConcrete baseEB thickness under thepackageThickness of theconcrete base0.35 m0.15 mDisposal borehole Total "length" 7.50 m 7.50 m 8.25 m7.4.2 Description of a handling driftThe disposal cells are arranged along handling drifts, whose axial dimensions are governed by thegeometry of the host block. These drifts are of the same design as the vitrified C waste repositorymodule drifts.They are dimensioned to be mechanically stable with no need for systematic rock supports. Driftsection is adapted for use by similar construction and operating machinery to that planned by SKB.They are linked two by two by interconnecting drifts installed roughly at 200 m intervals.Figure 7.4.3Cross section of a handling drift7.4.2.1 Handling drift dimensioning elementsBy using a tilting machine to emplace the packages in the cell, drift height can be limited to lowervalue. The required drift dimensions are about 4-6 m wide and 5.5 m high right above the appliancefor a fairly similarly designed machine to the one selected by SKB (see chapter 7.6.2).The geometry of the handling drift sections as in the case of the other drifts, is adapted to themechanical characteristics of the granite for long term stability with no other rock support than therequired one for operator safety. "Inverse U" geometry adapted to the technological dimensioningelements (heights at walls and at the arch, width) is adopted as the reference.Dossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY211/228