Thermal Ratcheting Behavior of a Cylindrical Structure with Plate-to-Shell Junction

Abstract

In this study the progressive inelastic deformation behavior of the 316L stainless steel cylindrical structure with plate-to-shell weld junction under cyclic thermal loads was carried out by structural test and analysis. This structural test intends to simulate the thermal ratcheting behavior occurring at the thermal liner of the liquid metal reactor as free surface of hot sodium pool moves up and down under plant heat-up, cool down and other thermal transients. A thermal ratchet load that heats the cylindrical structure up to 550°C was applied cyclically and residual deformation was measured. The temperature distribution of the test specimen along the axial direction was measured and was used for the ratcheting analysis. The thermal ratchet deformations were analyzed with the constitutive equation of the non-linear combined hardening model and the analysis results were compared with those of the test. The ratcheting deformations for different plate thickness in plate-to-shell junction and different traveling lengths obtained by the analysis using the combined hardening model were in reasonable agreement with those of the structural tests.