Nuclear Containment Vessel Anti-seismic Capacity Affected By Orifice

Nuclear energy is a kind of clean and highly effective energy. However, when the nuclear power plant has been destroyed, it will bring very serious effect. So, it is very important to enhance the research about security of nuclear power plant. Earthquake, which is a king of general natural disasters, has ruinous power. So it needs us do aseismatic analysis on nuclear power plant.In this paper, the main work is to analyse the anti-seismic capability of nuclear containment affected by orifice on containment, to summarize the rule, and to provide some advice to anti-seismic design. The detailed content as follows:First, through finite element software ANSYS, we create the complete model of nuclear containment and model of it with orifice, calculate the natural vibration of structure and oscillation model, compare the frequency and oscillation model affected by orifice. Based on the calculated results, when the orifice's dimension reach to 7m X 4m, the effect by orifice on these two items of anti-seismic capability is little.Second, used the general methods on anti-seismic design, the Mode Superposition Response Spectrum Method, to analysed two different models, and find the most weakness place on containment. Based on the calculated results, the most weakness place is happened at the bottom of the cylinder, and the effect by orifice on bottom shear force and side-displacement is also little.Last, used the methods of Time History Analysis , choosing three kinds seismic wave to calculate. Our intention is also to find the most weakness place on containment. The result is same, which is happened at the bottom of the cylinder. Based on the calculated results on three kinds seismic wave, when the orifice's dimension reach to 7m×4m, the stress along the orifice change greatly, reaching to 14%. The influenced area is big, which along the cylinder away from orifice 14m, and with the height increase in vertical, the range decrease.