On the independence of defense lines of a new nuclear power plant
Abstract
To ensure a good level of defense-in-depth and a very low risk, in new nuclear power plants, several defense lines are designed to prevent or to mitigate the consequences of an undesired event. To check the efficiency of these barriers and to avoid a simultaneous failure (or weakening) of several barriers, the non-existence of strong interdependencies between barriers has to be studied. The purpose of our work is to identify and to evaluate the impact of these interdependencies due to shared components between several defense lines. To reach this objective, several indicators based on PSA models have been defined and specific a computation procedure has been developed for each of them.