Dynamic Simulation Of A Nuclear Polar Crane's Seismic Isolation Device

A nuclear polar crane(NPC)is important equipment of a nuclear island.Possessing a large number of nuclear power plants,China is refining the NPC used in the domestic,third-generation nuclear power plants.A horizontal seismic isolation device will enhance the anti-seismic capability of an NPC.The dynamic performance of an NPC horizontal seismic isolation device determines its design load and also has effects on the containment vessel that the NPC is located,Therefore,the research on a horizontal seismic isolation device's dynamic simulation is meaningful to the anti-seismic design of a third-generation NPC as well as a containment vessel.A seismic isolation device used for the third-generation NPC was researched.System level horizontal vibrational dynamic equations were built involving containment vessel stiffness coupling.A simplified dynamic simulation model was established in AMESim software.Wheel force calculated by time history analysis method was entered to the simulation system.The model could well simulate the NPC's response under the vertical and horizontal coupling input after being equipped with seismic isolation devices.The influence of the horizontal seismic isolation device's parameters on the system's performance was obtained and the method to calculate stiffness of the device was discussedThe main work of the dissertation includes:(1)Main components of an NPC's horizontal seismic isolation device and different kinds of isolation devices were summarized.(2)The system's horizontal vibrational equations were obtained through Lagrange Equations.A system level simulation model was developed in AMESim.Equivalence stiffness of the containment vessel,trucks,et al was obtained by FEM.Swing load was modeled as a pendulum model.The corresponding parts were modeled in the simulation system.(3)Working process and principles were analyzed.In order to acquire the equivalent stiffness and damping coefficient of the device,the stiffness of a single disc spring was obtained by FEM and the damping load coefficient of stacked springs was calculated by equations.The device's simulation model was built.(4)The NPC's vertical vibrational equations were deduced and bridge wheel's force time history with load at different heights and bridge positions was calculated.(5)The influence of the isolation device's stiffness,pre-load and damping on the system's response were discussed.Simulations of several load combination cases identified the corresponding cases of the isolation device's largest compression and the containment vessel's max response force.An experimental model was built and it verified the validity of the simulation model.Finally,the method used to determine an applicable range of isolation stiffness is provided.Conclusions and future study's direction were described at the end of the paper.