Abstract: Based on the analysis of the structure features, the heat transfering characteristics of the nuclear reactor molten core and the cooling treatment strategy for the molten core, according to the analysis and comparison of the treanment measures for the molten cores of four type nuclear power plants, which are AP1000, EPR, VVER1000 and the boilingwater reactor in Fukushima, Japan, it was confirmed that to cool and to contain the molten core in a pressure vessel have very important function for mitigating serious accidents. The difference in treatment mode of molten core influences the range of application of reactor unit power in a certain degree. The treatment mode of molten core of new reactor pattern is improved obviously comparing with the previous one. The difference in measures of different reactors for treatment serious accident reflect the difference in design concept of different reactor patterns. The remedial measures of molten core for various reactor patterns were researched in depth, which has important value for ensuring the safety of nuclear power plants.

Key words: nuclear power plant, molten core, mitigating measure, serious accident