In the context of severe accidents, large R&D efforts throughout the world are currently directed towards ex-vessel corium behaviour. Among the mitigation means which can be envisaged, the European industries and utilities are considering the implementation of a core-catcher outside the reactor pressure vessel in order to prevent basemat erosion and to stabilize and control the corium within the containment. The CSC project focused on two key phenomena for external core-catcher efficiency, reliability and safety : spreading and coolability. An experimental programme, covering different scenarios and including both simulant and real materials provided a lot of results which constitute now a large database and which enabled the qualification of 2 computer codes. After a brief presentation of the project, this paper presents the results obtained.