Seismic mitigation performance and optimization design of NPP water tank with internal ring baffles under earthquake loads

The shield building of AP1000 is designed to protect the steel containment vessel of nuclear power plant. Therefore, the safety and integrity must be ensured during the plant life in any conditions such as earthquake. The purpose of this paper is to study the fluid-structure interaction of water in water tank and effects of internal ring baffle on the response of AP1000 shield building under strong ground motions. For this purpose, a fluid-structure interaction algorithm of finite element technique is employed to investigate the seismic response of water tank with internal baffles of different shapes and arrangements under artificial, El-Centro and Kobe earthquakes with peak acceleration of 0.3 g. Four optimal designed schemes of different ring baffle types are considered and the influences of various parameters such as vertical baffle height, arrangement locations, baffle height ratio and length of baffle on the dynamical response of shield building are discussed. The numerical results clearly show that the water tank with vertical ring baffle near the bottom of tank can limit the vibration of shield building and can more efficiently dissipate the kinematic energy of the shield building under different earthquake.