Fragility evaluation of nuclear containment structure subjected to earthquake and subsequent internal pressure

Abstract

Strong earthquake may lead to the rupture of pipeline inside the nuclear containment structure, which leads to overpressure of the nuclear containment structure. Therefore, nuclear containment structure suffers from the risk of subjected to earthquake and internal pressure sequence. However, studies on the performance evaluation of the nuclear containment structure subjected to earthquake and subsequent internal pressure sequence is very rare. This study presents fragility evaluation of the nuclear containment structure subjected to earthquake and subsequent internal pressure sequence. Firstly, detailed nonlinear finite element model of the nuclear containment structure is developed with layered shell element and concrete damage plasticity model. Then, 20 far-fault ground motion records are selected and scaled to different intensity levels to simulate different damage states of the nuclear containment structure. Nonlinear response of maximum strain, displacement and fragility of the nuclear containment structure subjected to earthquake and subsequent internal pressure sequence is analyzed. Results reveal that distribution of maximum strain and displacement of the nuclear containment structure subjected to earthquake and subsequent internal pressure are significantly different. Maximum displacement distribution of the nuclear containment structure subjected to earthquake is related to the ground motion intensity level. The variation of the median pressure capacity and logarithmic standard deviation presents a quadratic form with the increase of ground motion intensity level.