Development of the Phenomenological Uncertainty Analysis Methodology using MELCOR code for the Containment Failure Probability of Level 2 PSA

The severe accident considering nuclear power plants has extremely low occurrence probability. But if the severe accident occurs, hazards influenced to public are very large. So it is necessary that quantitative analysis of the severe accident occurrence probability, phenomenological analysis of the accident progression process, and the prediction of outcomes were necessary. Therefore the severe accident analysis using MELCOR code has been performed around the regulatory body, the Korea institute of nuclear safety (KINS). But the severe accident analysis has been done conservatively, because the severe accident phenomena have large uncertainties