An application of probabilistic risk analysis in nuclear criticality safety design

Current criticality safety practice requires a system design to meet the double contingency criteria. Since the probability of occurrence and the increments of the keff value resulting from the failure of each of the safety barriers are system dependent, a basis is needed to quantify the risk of the mitigative measures of a system design that follows the double contingency principle. This paper proposes a criticality risk assessment methodology which applies the probabilistic risk assessment to supplement the nuclear criticality assessment to provide a quantitative basis for the assessment of system risk and the criticality safety margin to achieve a safe design