Creep-fatigue test of a SA 316SS structure and comparative damage evaluations based upon elastic and inelastic approaches

A creep-fatigue in the reactor structures of a liquid metal reactor needs to be dealt with from a structural integrity point of view. This paper deals with the creep-fatigue damage evaluation of a typical geometrical discontinuity structure made of 316SS based upon both an elastic approach and an inelastic approach. The creep-fatigue structural tests of a 7 mm thick cylindrical structure and a 5 mm thick cylindrical structure have been carried out with a 1MN actuator and a 50 kW induction heater with a 1 h hold time at 550 °C. The strain behaviors, by an analytical method, and the damage evaluations were compared with those by tests. For an inelastic analysis by using the developed code NONSTA-VP, by implementing Chaboche's unified viscoplasticity model into ABAQUS, the methods to determine the material parameters are presented. The current comparisons show satisfactory results, but more efforts are needed to verify them in full.