The Ultimate Strength of Cylindrical Liquid Storage Tanks Under Earthquakes: Evaluation of Dynamic Buckling Behavior of Tanks Used in PWR Plants

Abstract

The new seismic design guideline for nuclear power plants, which was established in September 2006 in Japan, requires the consideration of residual risk for earthquakes beyond the design base. Seismic Probabilistic Safety Assessment (PSA) is the current available method to evaluate the residual risk of the nuclear power plant. Since 2002, Japan Nuclear Energy Safety Organization (JNES) has been carrying out seismic capacity tests for several types of equipment whose malfunction would significantly affect core damage frequency. The primary purpose of those tests is to obtain seismic capacity data and use them to increase the reliability of the seismic PSA. In this study, some elastic-plastic analyses considering the dynamic buckling behavior were performed to evaluate previous seismic capacity test results. The study confirmed that response displacement, residual deformation of the elephant-foot bulge (EFB) and local strain of tank after the EFB occurred could be evaluated analytically. Besides, a 3D FEM elastic-plastic buckling analysis using kinematic hardening law could simulate the behavior in the early stage of the dynamic buckling. In addition to those analyses, dynamic response reduction factor (Ds) of the actual material tanks, and influence of different materials on the energy absorption and seismic capacity were evaluated by using previous seismic capacity tests results.

A benchmark shaking table test on the seismic responses of an extra‐large LNG storage tank

“…Based on previous experimental results of the storage tanks, some researchers investigated the mechanical properties of storage tanks. Mikami et al [20] and Iijima et al [21] studied damage and failure mechanisms of the storage tanks in the limit state. Chalhoub et al, [22] Angelis et al, [23] among others, [24][25][26] carried out experimental studies on base-isolated steel tanks of different scales and structural types.…”

“…[ 20 ] and Iijima et al. [ 21 ] studied damage and failure mechanisms of the storage tanks in the limit state. Chalhoub et al., [ 22 ] Angelis et al., [ 23 ] among others, [ 24–26 ] carried out experimental studies on base‐isolated steel tanks of different scales and structural types.…”