Research On The Transient Dynamic Response Of The First Wall Of Z-FFR

The Z-pinch-driven fusion-fission hybrid reactor(Z-FFR)uses Z-pinch to generate energy from a large number of high-energy neutron-driven subcritical fission reactors.The resulting a ion energy will be in a time scale of less than a few milliseconds deposited inside the target chamber.The deposition of energy in the fusion target chamber on the surface of the first wall will bring about thermal effects such as ablation on the surface of the material,as well as mechanical effects such as thermal shock and thermal stress,and may produce material and structural responses such as yield,fracture,and spallation.The long-term effect of cyclic stress may have a significant effect on the life and structural strength of the first wall structure.In this paper,using the ANSYS program,the first wall model was established by the finite element analysis method,and the thermo-mechanical transient response analysis of the first wall under surface transient heat flow loading was simulated.Under a single transient pulsed heat flow loading,the heat flow impact energy is mainly concentrated on the tungsten layer portion of the first wall surface.The maximum temperature appears on the first wall surface is 409?.,and the temperature increase amplitude is 86?.The maximum temperature of the surface tungsten layer is lower than the recrystallization temperature(1300?)of the tungsten material,and the temperature gradually decreases as the depth increases.The temperature increase of the tungsten layer on the surface of the first wall at a frequency of 0.1 Hz is only a small part of the entire period,and the periodic loading does not lead to a cumulative effect of the first wall temperature.The thermal stress of the first wall is mainly distributed in the area with a large temperature gradient.The maximum Von mises stress at the surface of the tungsten layer is 140 MPa.The lower the temperature rise amplitude in the depth direction is,the smaller the stress is.The maximum stress and strain of the tungsten layer are in the elastic strain.The area does not exceed the yield strength of the tungsten material.The maximum tangential stress appears on the surface of the first wall,mainly compressive stress;the tangential stress on the first wall surface is dominated by the compressive stress.As the depth increases,the tangential stress in the middle of the first wall tungsten layer is converted into compressive stress.When the first wall surface is in a square wave configuration,stress concentration occurs at the square wave corners,and the maximum Von mises stress is 202 MPa.When the first wall surface has a sine wave configuration,stress concentration occurs at the trough,and as the surface roughness increases,the maximum stress and strain also increase.When the wave pitch is 20?m and the distance from the peak to the ideal surface is 20?m,the surface roughness is 12.7?m and the maximum Von mises stress is 473Mpa.When compared with the ideal surface,the temperature increase amplitude is increased by 25? and the maximum stress is increased by 333 MPa.