Architecture and management of a geological repository - Andra

5 – Repository ModulesTable 5.2.1Functions and main components of the C waste cell and moduleFunctionsPeriodMetal sleevePlug and metal shielded trapdoorCell plugSpacersModule sealingAccess drift backfillTransfer the packages to theirdisposal locationOperations XMechanically support the structuresOperation andobservationXProtect persons against irradiationOperation andobservationX xEnable the disposal packages to be Operation andretrievedobservationX xPrevent circulation of water After closure x XLimit release of radionuclides andimmobilise them in the repositoryAfter closure x XDelay and attenuate migration ofradionuclidesAfter closurexLimit mechanical deformation in theCallovo-Oxfordian argilitesAfter closure x x x x XDissipate heat All x XDivide the repository After closure XCaptions: X component essential to performance of a functionx component contributing to a function* Module separation of the repository does not constitute, strictly speaking, a safety function, but is a device adopted with safett objectivesin mind5.2.2.3 Solutions adopted abroadA number of countries are examining underground repositories for waste similar to French category Cwaste.In Belgium, the ONDRAF is looking at concepts for disposal in plastic clay (Boom clay) at a depth ofabout 200 m.The SAFIR 2 (2001) file [63] presents a concept in which the disposal packages are placed in astainless steel sleeve centred in the cell. The cell is a circular drift 2.4 m in diameter (see Figure 5.2.3).The packages are surrounded by a swelling clay barrier about 80 cm thick consisting of prefabricatedblocks of swelling clay mixed with sand and graphite. A concrete lining about 25 cm thick supportsthe ground. The drifts housing the packages are either through-passages or dead-ends (see Figure5.2.4). At emplacement, the packages have to be translated over about 200 m through the stainlesssteel tube.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM198/495