EVALUATION OF SEISMIC CAPACITIES OF KOREAN NUCLEARPOWER PLANT STRUCTURES BY SEISMIC FRAGILITY ANALYSIS

摘要

Seismic fragility analysis (SFA) has been utilized as a tool to evaluate the actual seismic capacity ofstructures and equipments in nuclear power plant (NPP) industry. This paper presents a brief discussionabout the Korean practical method of SFA, focusing on the basic input variables. In order to obtain morereasonable SFA results, an improved definition of the response spectrum shape factor that is one of theimportant input variables is proposed. The new factor is expressed as a term of linear algebraic sum ofmodal responses reflecting different modal contribution of each mode to consider the multimode effect ofstructural response.The efficiency of the new factor has been validated to use in practice through the case studies. For thepurpose, the five representative NPP structures in Korea were selected as objective models. The seismiccapacities of the structures obtained by considering single mode response were compared to thoseobtained by considering multimode response. The analysis results showed that the proposed factor can bemore effectively applicable to multimode structures with composite modal damping.