Life Assessment of Metals Used in Fusion Using R5 and RCC-MRX

In the European DEMOnstration Fusion Power Plant (DEMO) fusion reactor, in-vessel components face significant thermomechanical loads. They can experience severe damage due to high thermal load cycles, coupled with severe electromagnetic loading and unprecedented levels of irradiation damage. Cooling fluids are used to extract the heat to reduce operating temperatures and for energy production. Other elements, like the shielding liner and reflector plate supports, may also experience severe creep-fatigue and irradiation damage. To assess the high-temperature structural integrity of such components, procedures in R5 and RCC-MRx are used to assess creep-fatigue, whereby fatigue is assumed from pulsed reactor operation and creep from sustained load at high temperatures. This project aims to conduct a creep-fatigue assessment of a representative joint, tungsten-to-tungsten via copper brazing (WCu). However, due to a lack of data on such fusion-specific joints, two more conventional joints are studied: a 316L similar metal weld; and a 316L-to-10CrMo9-10 dissimilar metal weld Methodologies used for creep-fatigue assessments within R5 and RCC-MRx are detailed and compared, then applied to each material using the appropriate materials data. The two procedures share similar underlying approaches however, some subtle differences may become important within an assessment.