The approaches on the determination of frequency-consequence criteria for risk assessment of new reactors

The risk is often expressed in terms of surrogate measures such as core damage frequency (CDF) or large early release frequency (LERF), even though the risk in LWR PRAs can be generally expressed as a consequences resulting from exposures. These surrogate measures and the criteria associated with them are LWR-specific and not applicable to all reactor designs. Therefore, a criterion that specifies limiting frequencies for a spectrum of consequences, from none to very severe, needs to be established for new reactors. Based on this concept, NRC proposed the Technology Neutral Framework's frequency-consequence (F-C) curve derived from current regulatory requirements. Each country has also proposed or stipulated various F-C criteria for new or existing reactors. In this paper, F-C criteria for new reactor licensing or existing LWRs in each country are systematically surveyed and analyzed in order reasonably to determine the appropriate F-C criteria