Radiation source terms assessment for identifying correlations between LERF and early fatality

Abstract

The correlations between Large Early Release Frequency and Early Fatality need to be investigated for risk-informed application and regulation. The decision-making criteria using the measures of CDF (core damage frequency) and LERF (large early release frequency) are introduced in the RG-1.174, while there are no specific criteria on early fatality yet. Since a huge uncertainty and large cost are required for evaluating fatality, a simplified LERF assessment methodology needs to be developed. The first step to develop this methodology is to identify the factor with respect to two variables' correlation for the risk-informed decision-making. In this regards, the accident consequence analyses has been performed for assessing health effects caused by radioisotopes released from severe accidents of nuclear power plants. In this study, the MELCOR, the MACCS, and the AIMS code are used in succession for evaluating source terms quantitatively regarding health effects. This study also derived the conversion factor between early fatality and LERF. It has been obtained from each organ dose and whole body dose calculations using MACCS code with respect to the residential distance. The results of this study may contribute to defining the LERF and to developing a new measure for risk informed decision-making.