Finite Element Simulation of Thermal Stress in Sic Coating as Tritium Penetration Barrier

As the tritium penetration barrier coating is used at high temperature, thermal stress is inevitably generated in the system. The thermal stress would cause the coating to delamination or cracking, which seriously affects the safety of the fusion reactor. In this work, a two-dimensional finite element model represented the SiC tritium barrier coating system was established. The relevant parameters that affected the magnitude of the thermal stress of the system, such as coating thickness, substrate thickness and ambient temperature, were discussed in detail. Furthermore, the reliability of simulation results was verified by analytical formulas. The outcomes showed that the influence of dimensions and service environment on thermal stress was sensitive. With the path of stress moving close to the edge of the model, the variation of the maximum radial stress in the system showed a gradual decrease trend. However, the maximum shear stress increased toward the edge. Since the adhesive strength of the coating mainly depended on the shear stress, these findings suggested that the coating detachment may initiate at the edge