Architecture and management of a geological repository - Andra

9 – Nuclear operating resources in the repository9.3.4.1 Justification for principle chosen• Required functionsThere are two types of disposal package. CU1 packages are characterised by a weight of about43 tonnes and a length of about 5.40 metres. CU2 packages are characterised by a weight of about10 tonnes and a length of about 4.60 metres.The installation of these heavy and large-sized disposal packages in a horizontal cell of circularsection requires, as for C packages, a remote-controlled machine capable of being contained in theshielded transfer cask and of transferring the package to its final position with a functional clearancebetween the package and the cell as small as possible.• Choice of the package handling principleIn the same way as for the installation of C waste packages, three principles have been identified forthe transfer of the disposal package (SeeFigure 9.3.17):- transfer by a self-propelled pusher robot with jacks with sliding of the package (principle similarto that chosen for C packages),- transfer by a self-propelled robot with rolling of the package requiring the incorporation of wheelsinto the container structure,- transfer of the package by a robot using the air cushion principle.Figure 9.3.17The handling principles envisaged for spent fuelsIn the case of CU1 packages, the air cushion principle was preferred to the other two alternativesenvisaged. The weight of CU1 packages (43 t) is in fact almost incompatible with the principle ofpushing by sliding which would require the production of a very high thrust force. The optionconsisting of including wheels in the container structure would complicate its manufacturing processand would significantly increase the length of the package and its weight.The air cushion principle has been the subject of a representative test by the Swedish agency SKBusing a demonstration model of similar dimensions to the packages in question. [81]. More recently,DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM359/495