Experiment and analysis on the creep-fatigue damage of a 316SS nonlinear structure in liquid metal reactor subjected to a cyclic loading with 1HR hold time

The high temperature environment of the Liquid Metal Reactor (LMR) may cause the creep-fatigue damage in the reactor structures and it is important 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 subjected to both a tensile loading and a high temperature loading. The creep-fatigue structural test of a cylindrical structure welded with a conical shell has been carried out with a 1MN IST actuator and a 50 kW induction heater with 1 hour hold time at 550 degree C. Total 400 cycles of testing were performed and the creep-fatigue damage in the discontinuous regions and the defect front, which were prepared by an electric discharge machining, were investigated using nondestructive methods. Also, the high temperature structural analysis program (NONSTA-VP) implementing Chaboche's unified viscoplasticity model into ABAQUS, developed to analyze creep-fatigue behavior, has been used to evaluate the creep-fatigue damage and the result has been compared with those of the structural test. The creep-fatigue crack initiation and growth behavior at the defect front were assessed and compared with the test results. (authors)