Developing a Methodology for Identifying Correlations between LERF and Early Fatality

One of the reasons to use the measures such as core damage frequency (CDF) and the Large Early Release Frequency (LERF) is to assess, from a risk perspective, the impact on the current licensing basis of any changes that may be proposed by various licensees. The use of CDF and LERF has been judged appropriate since the regulatory utilities have performed level-1 and level-2 Probabilistic Safety Assessments (PSA). Therefore, information on core damage frequency, containment failure likelihood, containment failure mode, and radiological releases, are readily available from these studies. Difficulties exist in defining 'large' release frequencies, since there are wide spectrums of fission product releases that are estimated as likely to occur following severe accidents, with their expected release quantities ranging over several orders of magnitude and occurring at various times following accident initiation. In this study MELCOR, MACCS, and AIMS code are used in sequence for evaluating source terms quantitatively regarding health effects, which depend on release characteristics of radioisotopes during severe accidents