Seismic Analysis Of A Reinforced Concrete Containment Vessel On Isolating Devices

Developing Nuclear Power Plant is our country's energy program. Becauseof fatalness of earthquake damage, it is very important for us to do earthquakeresistance research on Nuclear Power Plant(NPP). Comprise with the traditionalanti-seismic design approach, seismic isolation research on NPP is studiedseldom. Seismic isolated structure system is a passive active control system,which is different from traditional anti-seismic structure system. Through settingisolation layer, the characteristics of structure system which include freevibration frequency and damping are altered, and the system responses in shockare smaller than traditional structure system.In this paper, the following researches take some unclear power station asan example and have been done based on the up-to-date structural seismicdesign code and isolation technology.First, because of the complexity of the NPP's structure, the model of NPP isalso very complex. So some years before the multi-lumped mass model has beenusually taken and the three dimensional finite element model is seldom usedbecause of its assembling complexity and long calculation time. In this paper thethree dimensional finite element model is modeled, through ANSYS finiteelement software.Second, using the finite element model, the mode and frequency of theunclear power plant containment is calculated by using software, The resultsproofed that the stiffness of the containment is high and the isolation technologycan be applied to the containment of NPP. According to the up-to-date structuralseismic design code, the response spectrum and time-history response analysis istaken to study the earthquake response analysis of the containment model. Theresult about containment earthquake analysis which is gotten by the two methods is almost the same. The maximum stress is happened at the bottom ofthe cylinder.Third, two-dimensional isolation is taken in this paper. The isolation deviceis modeled by two elements: combin40 is adopted in horizontal direction andcombin14 is adopted in vertical direction in ANSYS software. The resultsshows that upper structure with isolation device is mainly overall translation, theacceleration still transmits upward, acceleration in the top is greatly reduced anddisplacement is incremented compared with the structure without isolationdevice.