The interactions of molten core with different types of concretes in EPR severe accident

Sacrificial concrete is very important in the advanced European pressurized water reactor (EPR). To compare the behaviors of different kinds of sacrificial concretes in the EPR reactor pit, several sacrificial concretes were adopted in the calculation of molten core–concrete interaction molten core-concrete interaction (MCCI), i.e. the “FeSi” concrete, the siliceous concrete, and the limestone concrete. Using a computer code MELCOR, the main parameters, i.e. concrete ablation depth and rate, hydrogen generation mass and rate and temperature in a typical small break loss of coolant severe accident in EPR were calculated. The results indicate that the ablation rate decreased in the order of the “FeSi” concrete, siliceous concrete and limestone concrete. Meanwhile, the generated hydrogen mass of the “FeSi” concrete is 13% less than that of the siliceous concrete. In addition, as the basemat of reactor pit is melt through, the temperature of melt pool is the lowest for the limestone concrete and the temperature of siliceous concrete is slightly higher than that of “FeSi” concrete.