Fatigue Damage Analysis of Reactor Vessel Model Under Repeated Thermal Loading

摘要

The local approach to fracture based on continuum damage mechanics and the finite element method has been applied to the low-cycle fatigue damage and fracture behavior of a nuclear reactor vessel model subjected to repeated thermal loading due to the alternate inflow of high-temperature and low-temperature liquid sodium. The viscoplastic strain based on the creep plasticity isotropic hardening theory with damage evolution is used in the analysis. The calculated results for the neibourhood of intake nozzle and the conical body have been compared with the experimental results. The calculated results considering the difference of mechanical properties of parent metal, weld metal and heat-affected zone have corresponded well with the experimental results for the initiation and propagation of thermal fatigue cracks.