The magnitude of the thermal stress in the first wall system is one of the key factors affecting the safe operation of the fusion reactor.

This study aims to investigate the effect of a rough substrate on the thermal stress in the W/316L stainless steel first wall system.

The finite-element analysis software Ansys Workbench was employ to analyze the distribution of thermal stree in a W/316L stainless steel first wall system with a rough substrate. Depth analysis was conducted on factors such as the temperature, coating thickness, and substrate thickness that affect the magnitude of thermal stress. Meanwhile, starting from the interface shear stress in the system, the influence of rough substrate on the bonding strength of coatings was simultaneously investigated.

The simulation results indicate that the thermal stress in the rough substrate system increases with the the increase of temperature and substrate thickness, but decreases with the increase of coating thickness. The maximum thermal stress and the adhesive strength between the coating and the substrate are raised by the introduction of the rough substrate.

Results of this study can provide reference for the development of high-adhesive strength first wall coating systems.