Architecture and management of a geological repository - Andra

7 – The shafts and the drifts7.3.4.2 Package transfer rampPackages are lowered and transfer casks raised by means of a ramp with electric vehicles similar tothat used for the horizontal transfer of packages in the repository (see chapter 9). Such a structurewould allow eliminating the risks of falling from a great height. In the example given, the drift issloped 10%. It general shape is helical. Each spiral is square shaped and consists of straight sections80 m long and curves having an inner radius of approximately 10 m. The section length was limited inthis example in order to reduce the potential speed (50 km/h at most) of a package transfer vehicle incase its braking system should fail. At each turn an escape way would allow stopping the vehicle incase it misses the turn. The drift has a usable diameter of approximately 7 m. A 3 m dia. vertical airshaft interconnects the various spirals and ensures an air circuit specific to the ramp independent fromthe repository’s ventilation.During closure, the assembly is also sealed in a way similar to that of the construction ramp.Figure 7.3.6Ramp for the transfer of packagesDOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM299/495