Architecture and management of a geological repository - Andra

5 – Repository ModulesThe internal sleeve of the spent fuel cells is of the same type as that of type C cells. Its thickness isadapted to the diameter of the packages. It would be possible to install fittings to make it easier toguide and retrieve packages (for example rails or shims or ceramic linings).Figure 5.3.12Internal equipment of the CU1 sleeve• Components and functions of the cell head in the operating configurationThe metal lining is identical to that described on the inside of the cell, except that there are noperforations in the head of the cell.The swelling clay buffer rings in the future sealing zone are identical to the rings around thepermanent sleeve.The prefabricated concrete rings are the same size as the swelling clay rings. These rings support thetemporary sleeve during package insertion. They participate in radiological protection. They confinethe clay during its re-saturation and transfer the clay swelling thrust to the access drift.• Description of the access driftThe size of the access drift depends on the spent fuel package handling requirements. Due to theirlength, the packages are transported lengthwise in the drift. Consequently, they have to be turned orpivoted in order to insert them in the cell.For the current section, the size of the passage for the package transporter is approximately 4 m by4 m. Its inclusion in a roughly circular section requires an internal diameter of approximately 6 m.This figure is close to that of the drift for type C modules; the support and lining can thus be thesame 94 : support by 4 m rock bolts and shotcrete, metre thick B60 concrete lining poured in-situ.94The excavated section should be optimised: the useable section given, elliptical in shape, minimises stresses and, thereforer, thethicknesses of the coating; however, a shape more akin to the transporter’s square cross section would allow a smaller useable section.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM241/495