A Comprehensive Comparison of Creep-Fatigue Life Assessment Through Leading Industrial Codes

Creep-fatigue damage has been recognized as a critical failure mode for high-temperature structures. In fusion power reactors, plasma-facing components endure complex loading conditions, resulting in high thermomechanical stresses. These components, often made from 316L material, joined to ferritic-martensitic steels, face significant challenges due to the interaction of various loads affecting their material properties and structural integrity. This paper compares internationally recognized methods for creep-fatigue assessment: the R5 procedure and the RCC-MRx code.

The study evaluates the differences and similarities in creep-fatigue assessments between these procedures, providing a global overview and a detailed comparison. The conservatism of both approaches are assessed by comparing the material properties dataset, total strain calculations, and lifetime estimates for 316L at 550 °C. Additionally, the welding assessment approaches of RCC-MRx and R5 are compared and applied to similar metal welds (316L-to-316L). Further, dissimilar Electron Beam Welded metals (316L-to-10CrMo9-10) are prepared, investigated and characterized using creep-fatigue experiments to compare the predicted service life using RCC-MRx.