Fatigue Crack Propagation Experimental Evaluation and Modeling in an Austenitic Steel Elbow From a LMFBR Primary System Piping

Abstract

In this work the behavior of high temperature (400C) low-cycle fatigue crack propagation during in-plane bending of an elbow from Monju Liquid Metal Fast Breeder Reactor (LMFBR) is presented in three stages. First, experimental measurements made in a real-size laboratory specimen are presented. This test was carried out under displacement-controlled conditions, with artificial defects introduced in the crown parts, where the maximum stress arises. Second, the experimental setup is simulated making use of Finite Element Analysis (FEA), in order to obtain the actual stress distribution through the loaded elbow. Finally, based on the FEA data, deterministic fatigue crack propagation based on the J-integral criterion is compared with the experimental data. Overall a good agreement was observed between experimental and analysis results, highlighting our capacity to evaluate such phenomena without necessarily incurring into extensive experimental work. In the future these tools will keep supporting the cost-efficient acceleration and improvement of LMFBR design and inspection criteria.