Nuclear power plant's major accident countermeasure calculation and analysis methods

The present invention relates to nuclear power plant design technology, be specifically related to a kind of nuclear power plant major accident countermeasure calculation and analysis methods.The method is by carrying out computational analysis to the major accident evolution and principal phenomena that may cause major accident critical event sequence, system assesses the ability of nuclear power plant's reply major accident all sidedly, determine and prove the prevention and mitigation strategy in engineering, major accident actual capabilities taked, thus avoiding the npp safety shell caused due to major accident to lose efficacy.