How do we define LEBF

It is necessary to satisfy both safety and economic at the same time in operating nuclear power plants. In order to implement it, USNRC encourages probabilistic risk assessment techniques to implement safety decision making and enhance regulatory efficiency and issues related regulatory guidelines. In domestic nuclear institutes and industries have started risk-informed regulations researches and regulation guidelines will be issued in short time. The paper provides the rationals and analysis method of LEBF, large early release frequence used in risk-informed regulation as a safety parameter. The proposed method for LERF is simple so that it is adaptable to risk-informed regulation while providing sufficient information on risk induced from severe accidents