Dynamic Analysis Of Steel Containment Vessel Under Pressure And Earthquake Action

Nuclear power has become an important energy sources for human use. The development of nuclear power construction in China is very rapid now, but China is also one of earthquake-prone countries, so the research on the seismic performance of the nuclear containment vessel which is the last safeguard of nuclear island is extremely important. As one of the most advanced nuclear power plant, advanced passive-safety 1000MW nuclear power plant (AP1000) is be introduced into China recently. In this paper, based on ANSYS software, the three dimensional finite element model refer to the steel containment vessel of AP1000 is established and the seismic performance and dynamic response of it when under pressure and earthquake action is analyzed. The main research contents and results as follows:Firstly, when steel containment vessel is under pressure, the equivalent stress value of theoretical calculations and numerical simulation analysis is worked out separately with ANSYS software. Compared with the two results above, the error is less. According to these results, they display that under design pressure, although the equivalent stress at the junction of upper head and cylinder body as same as lower head and cylinder body is large, the maximum value is less than the material yield stress, so the structure is in the elastic state with sufficient emergency capacity. In addition, the deformation of structure is small.Secondly, consider whether or not the steel containment is under pressure, the modal analysis is carry out. And its natural frequencies and modes which are from modal analysis under different situations are as the basis for dynamic analysis. The results demonstrate that natural frequencies exist always in pairs and mode shapes show symmetrical. Besides, the natural frequencies increase as the internal pressure increase, whereas the natural frequencies reduce as the external pressure increase.Thirdly, based on time-history analysis methods, this paper studies the dynamic response of steel containment structure motivated only by earthquake. Stimulated separately with one actual seismic wave and two different artificial seismic waves, this article found the corresponding displacement and acceleration time history results and the corresponding maximum equivalent stress. The results show that the response to seismic motivation is less and the structure has sufficient seismic margin, meeting the requirements of relevant specifications.At last, in order to contrast with the dynamic response results which only consider the action of earthquake, time-history analysis methods are used to analyze the dynamic response of steel containment structure considering the action of both pressure and earthquake action. It turned out that the main factor affected the mechanical performance is pressure, but the entire structure is in elastic state and the steel containment vessel has good anti-seismic performance.