Architecture and management of a geological repository - Andra

The robot is traversed similarly to the robot used for emplacement purposes. The principle consists ina step-by-step forward movement by means of a longitudinal cylinder and side cylinders. Oneadvantage of this system is that it is rather insensitive to a damage sleeve surface condition. It alsoprovides an opportunity to exert a significant thrust if necessary.Pick-up of the package top section–a function specific to retrieval operations–is carried out using twovertical hydraulic cylinders located at the head of the retrieval carriage which slightly lift the packagetop section to facilitate the retrieval operations (Figure 10.4.12).Figure 10.4.12Pickup and retrieval principles of disposed packagesThe retrieval winch considered is capable of producing a tensile strength of about 160 kN for packagesC and 800 kN for spent fuel packages. The tensile force is transmitted to the robot and to the packageto be retrieved via a multi-cable pulley system.Like for installation, all the operations are carried out semi-automatically under the supervision of anoperator located in the control station of the docking shuttle by following a reverse procedure fromthat used for installation.10.4.2.3 Retrieval conditions at the “After cell closure” stageThe "after closure" stage corresponds to the configuration in which the cell is sealed by a plug ofswelling clay mechanically constricted by a concrete plug (Figure 10.4.13). The access drift is stillaccessible.At this stage, package retrieval remains technically feasible. However, like in the previous stage, thisoperation shall be preceded by a cell head section reconditioning phase.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM429/495