Probabilistic seismic performance evaluation of nuclear containment structure subjected to far-fault ground motions

Abstract

This study presents probabilistic seismic performance evaluation of nuclear containment structure subjected to far-fault ground motions. To achieve this objective, refined finite element model of nuclear containment structure is established and incremental dynamic analysis (IDA) is performed automatically using pre-processing and post-processing scripts. Cracking status, roof drift, damage dissipated energy and floor acceleration of the nuclear containment structure is discussed. Furthermore, probabilistic seismic safety margin of nuclear containment structure is quantitatively evaluated by median value method and confidence interval method. Finally, a closed-form solution for the annual frequency of exceedance for the roof drift of the nuclear containment structure is derived, and the effectiveness of the closed-form solution is verified by the classical direct numerical integration method. Annual frequency of exceedance for the roof drift of the nuclear containment structure corresponding to different performance levels is analyzed. Results indicated that the bottom of nuclear containment structure is the most vulnerable location. In general, nuclear containment structure subjected to far-fault ground motions is dominated by shearing cracks. When the ground motion intensity level is less than 0.4 g, damage dissipated energy of the nuclear containment structure is very small. In general, with the increase of elevation, acceleration amplification factor of the nuclear containment structure increases rapidly. Probabilistic seismic safety margin of the nuclear containment structure evaluated by median value method tends to be conservative. Analytical and classical numerical integration method provides almost the same prediction of the annual frequency of exceedance for the roof drift of the nuclear containment structure, which indicates the effectiveness of the proposed closed-form solution.