Modeling of fatigue-type seismic damage for nuclear power plants

Assessment of the safety of the nuclear power plants and evaluation of the plant condition after an earthquake require the knowledge of the fragility of structures and components. In the paper options for improvement of existing methods of the modelling of plant fragilities are outlined based on the interval and p-box theories, use of cumulative absolute velocity as damage indicator and first-passage description the fatigue type failure mode of the components.