The results of flooding experiments with blocked arrays (FEBA) are presented, a program performed at Kernforschungszentrum Karlsruhe within the framework of the Project Nuclear Safety (PNS). Experiments performed out of pile show that coolant channel constrictions of up to 90% do not lead to significant core coolability problems during reflood. This is even true for low water injection rates corresponding to a flooding velocity of 2 cm/s for the cold bundle. The results of the thermal-hydraulic experiments cover rather widely the cladding temperature range below 1000°C. However, outlining the total range of heat transfer conditions in severely damaged rod bundle geometries, investigations performed within the framework of the PNS are mentioned as well. They provide information about the condition of rod bundles being exposed to temperatures of up to 2000°C prior to reflood.