Creep and Fatigue Analysis of Alloy 625 Tube in Molten Salt Solar Receiver

Abstract As one of the most core equipment in the solar thermal power generation, the molten salt solar receiver needs to undergo high temperature and daily cyclic loadings. The Nickel alloy materials are generally used for the construction of molten salt solar receiver to ensure its structural integrity under severe operating conditions. Compared to other failure modes, the combination of creep and fatigue is more worthy of attention. In recent years, Alloy 625 tube has gradually been used in molten salt solar receiver for its cost-effectiveness and good performance in high temperature. However, the study on creep and fatigue failure of Alloy 625 tube in molten salt solar receiver has been rarely reported. In this work, the thermal-mechanical coupling stress analysis for a molten salt solar receiver is conducted using finite element code, the creep and fatigue failure are assessed based on the calculated stress results and high temperature creep and fatigue data in literature. In addition, the creep and fatigue damage for different loading conditions and tube sizes are studied. The results are discussed and some conclusions are provided for engineering design.