RETRAN Analysis of Boiling Water Reactor Accidents

System success criteria used in probabilistic risk assessments (PRAs) have typically been based on conservative licensing success criteria. The availability of best-estimate thermal-hydraulic computer codes such as RETRAN provides a means to review and determine if more realistic system success criteria can be justified. How RETRAN can be used to establish realistic system success criteria is demonstrated, and how realistic versus conservative system success criteria can significantly improve a PRA’s evaluation of plant risk is illustrated.