Seismic fragility analysis of vertical water-storage tanks for nuclear power plants

Large-scale vertical water-storage tanks are important safty facilities of nuclear power plants. As the tanks have sometimes failed with loss of contents during strong earthquake shaking, their seismic fragility analysis play important roles in probabilitic safty assessments for nuclear power plants. This paper reviewed various failure modes and then the general procedures of seismic fragility analysis were introduced. The methods for evaluation of seismic response, seismic capacity and their uncertainties were also presented. (authors)