Research on FSI effect and simplified method of PCS water tank of nuclear island building under earthquake

Water tank is one of the most important components of passive containment cooling system (PCS) in advanced nuclear power plant. Moreover, the dynamic characteristics of shield building and auxiliary building might be changed because of fluid-structure interaction (FSI) of the PCS. Therefore, FSI between cooling water and the shield building should be considered in the dynamic analysis of the nuclear island building. To study the FSI effect and propose an effective and simplified method, three numerical models were established and analyzed under three-dimensional seismic loadings. Acceleration time histories of reference points in the shield building and auxiliary building were got and floor response spectra were calculated. The results show that FSI effect could not be regarded to decrease the seismic response simply but it should be considered in structure design and analysis. A simplified model is proposed in this study and proved to have a good agreement with the FSI model in the curves of floor response spectra. The conclusions could provide reference for further study in the field of nuclear island building. (C) 2017 Published by Elsevier Ltd.