[en] Full text: The Swiss utilities have chosen two different ways for the management of their spent fuel after initial on-site cooling: either reprocessing at La Hague plant (COGEMA) and Sellafield plant (COGEMA); or interim storage at the Central Interim Storage Facility called 'Zwischenlager Wuerenlingen AG' ( ZWILAG). Following international call for tenders, COGEMA LOGISTICS were awarded contracts for the supply of dual-purpose transport and storage casks for the interim storage of various spent fuel assemblies. All these casks belong to the family of the TN 24 dual purpose spent fuel storage casks in operation in the USA and in Belgium as well. They offer utilities a modular solution for the interim storage of spent fuel in robust metal casks which are fully suitable for off site transports. This flexible product can be readily adapted to suit individual user needs. The Leibstadt Nuclear Power Plant (KKL) has purchased six licensed dual-purpose TN97L spent fuel casks (97 BWR type fuel assemblies capacity). Three of them are already in operation at ZWILAG. COGEMA LOGISTICS has also delivered a dual-purpose TN52L spent fuel casks (52 BWR type fuel assemblies capacity) presently used for transport of spent fuel for reprocessing. The Goesgen Nuclear Power Plant (KKG) has purchased four licensed dual-purpose TN24G spent fuel casks (37 PWR type fuel assemblies capacity). They are all in operation at ZWILAG. The Muehleberg Nuclear Power Plant (BKW/KKM) has purchased 2 TN24BH spent fuel casks (69 BWR type fuel assemblies capacity). At the time of this abstract, cold trials are carried out involving the shuttle transport cask TN9/4 procured by COGEMA LOGISTICS as well. This paper will present the main features of these casks and the main steps of their development and implementation: 1) Main features of the casks: - The basic structure is a thick steel cylindrical forging with a welded on forged bottom and two forged steel lids. Containment and gamma shielding features of the cask are mainly provided by this basic structure. - 4 or 6 trunnions are attached to this structure for handling, tilting and tie down. - Inside the cylindrical cavity, a Boron aluminium basket is fitted and provides a structural support for the fuel assemblies and criticality control. - Surrounding the cylindrical cavity, a resin layer is encased in an outer shell and provides the neutron shielding features of the cask. Heat conductors ensure the thermal evacuation of the heat from the main shell to the outer shell of the cask. - A leak tightness monitoring system and an anti-aircraft crash cover (when needed) are installed during the storage period of the cask. - A set of shock absorbing covers is fitted to the flask for transport operation, as well as lateral impact limiters for some cask design. 2) Main steps of their development and implementation: - manufacturing and licensing (transport and storage) - transport and on-site handling cold trials using the ancillary equipment and the real vehicle - spent fuel loading and transport to the storage site - storage. (author)