Liquid Ejection Through Orifices by Sparging Gas: The PERCOLA Program

Corium coolability after a severe PWR accident involving core meltdown and RPV failure is one of the main items in nuclear safety. The case considered here is a situation in which the corium is supposed to spread over a concrete floor and is flooded by water. In this frame, many researches are performed to study the physical phenomena which may enhance the heat transfer between the corium and the water pool. Among them, the melt entrainment above the corium crust by the sparging gas released by the concrete ablation appears as a potentially efficient cooling mechanism. The main target of the experimental program PERCOLA is to provide qualitative and quantitative information on this entrainment phenomenon. The first part of this paper is devoted to a general description of the experimental program and to the presentation of the main results. In a second part, the attention is focused on the modelling of the liquid entrainment phenomenon and to the comparison between the experimental data and the calculation results of two different entrainment models.