The comparison of frequency-consequence (F-C) criteria in evaluating the risk of new or existing reactor

The main purpose of this paper is to review and analyze specific or technology neutral risk assessment tools known as frequency-consequence (F-C) criteria in new reactors licensing or existing reactors. Several countries have stipulated, proposed or are developing various F-C criteria for new reactors and existing reactors. This paper summarizes the comparisons of F-C criteria for new reactors licensing or existing reactors in various countries. In general, three types of F-C criteria were represented, i.e. multi-stepped conservative F-C criteria, limit-to-objective buffed F-C criteria, and practical dose sign F- criteria. The F-C criteria proposed by NUREG-1860 are generally more conservative than those of any other guidelines except those of several countries infrequency ranges above 10-4. In addition, these criteria are less conservative than those of any other countries except for ICRP 64's and HSE's limit in frequency ranges below 10-4. In the frequency ranges below 10-4 each country especially has very different consequence level. Therefore, the method on determining each consequence of this rare event or accident sequence needs to be properly selected in specific risk evaluation, based on safety features of new reactors. These comparisons could be usefully utilized in determining or selecting technology- neutral or specific F-C criteria for new reactors or existing reactors. (authors)