Structural Dynamics Analysis Of Tokamak Device For Plasma Facing Components

As the transition zone between high temperature plasma and material,the design of the divertor system covers the frontier technology of fusion plasma physics,structure manufacturing technology and structural evaluation.The divertor plays an important role in discharging the heat and high-energy particle flow generated by the fusion reaction.Therefore,the divertor is one of the key factors related to the normal progress of the fusion reaction.In view of the harsh operating environment of the divertor,it is necessary to analyze the dynamic characteristics of the divertor,so as to provides a basis for improving the structure and materials of the divertor.Based on the introduction of structural dynamics and finite element theory,this paper analyzes the influence of vertical displacement event(VDE)and plasma large rupture event(MD)on the divertor during the fusion reaction of the tokamak device.Due to the complexity of the load type,the influence of the Halo current generated by the vertical displacement event on the divertor is mainly analyzed.The divertor model is simplified by means of finite element software.It is helpful to understand the natural frequency and vibration characteristics of the structure to avoid the resonance phenomenon of the divertor during operation.In order to reduce the complexity of the calculation,this paper uses the static elastoplastic analysis equivalent to dynamic elastoplastic analysis to judge the performance of the divertor under dynamic load.In the operation of the HL-2M device,due to the instability of the central plasma,transient events such as vertical displacement events often occur.The fast quench of the current leads to a large Halo current on the tokamak device,which interacts with the magnetic field to generate a high electromagnetic force and electromagnetic pulse load,which will cause fatal damage to the diverotr.First of all,the superposition method and the stepwise method were used as the comparison without considering the material plasticity to verify the credibility of the calculation results of the superposition method.Based on the modal analysis results of the divertor,the static analysis was equivalent to dynamic analysis,and this method was used to obtain the dynamic amplification factor ξ of the load.Finally considering the plastic properties of materials,the static load we applied is ξ times of the maximum dynamic load,the calculation results by the fourth strength theory and SDC-IC standard to judge,the divertor support block has produced the yield strain,but in more than one under cycle loading,the plastic strain values did not significantly increase,the maximum stay near 0.8%.It is estimated that the support block can withstand about 2500 cycles of load,which conforms to the engineering design requirements of HL-2M.