[en] In future light water reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel meltthrough during a core meltdown accident. In the case of a postulated core melt down accident in the EPR (European pressurized water reactor) the ex-vessel melt shall be retained and cooled in a special compartment inside the containment to exclude significant radioactive release to the environment. After failure of the reactor pressure vessel the core melt is retained in the reactor cavity for ∝ 1 h to pick up late melt releases. The reactor cavity is protected by a layer of sacrificial concrete and closed by a steel gate at the bottom. After meltthrough of this gate the core melt should be distributed homogeneously in a special spreading room. A series of experiments has been performed to investigate the erosion of the sacrificial concrete as well as the gate ablation using alumina-iron thermite melts as a simulant for the core melt. Two different sorts of sacrificial concrete have been studied so far: boro-silicate glass concrete and a concrete based on Fe₂O₃/SiO₂. Erosion velocities of the sacrificial concrete, the homogeneity of the melt front and steel gate ablation results are presented in this report. (orig.)