Analysis of Nuclear Power Plants Involving Failure-Correlation of SubsystemsCaused by Earthquake

摘要

Earthquakes are unavoidable natural hazards and difficult to predict. Their damaging potential must be considered forrnsensitive constructions including dams, mines, nuclear power plants (NPPs), underground depositories for radioactive wastes.rnAll seismically induced failures could be with common causes. There are many causes that induce dependent failures amongrncomponents and subsystems. In probabilistic safety assessments (PSAs) of NPPs, many different practical techniques havernbeen developed to handle correlations among structures and components.rnAnother important PSAs issue concerned in NPPs is the assessment of aging effects, which degrade the performance ofrncomponents, systems and structures. This kind of degradation is time-dependent and comes from the interactions of manyrnfactors.rnThe treatments of dependent failures and aging effects are two comprehensive issues involved in PSAs of NPPs. Manyrnstudies and programs developed on seismic fragility evaluations include dependent failures but where aging effects are notrninvolved. Virtually, these two aspects need to be incorporated into seismic PSAs of NPPs. In the present paper, an approachrntreating dependent failures among components is developed. That is applied to seismic fragility evaluation of a subsystem,rnwhere the aging effects on capabilities of components and subsystems are taken into account. An example is given tornillustrate the approach developed.