NUMERICAL CALCULATION OF FATIGUE CRACK GROWTH FOR THE STRUCTURES OF ELBOW AND TEE PIPE BASED ON RCC-MR A16 CODE

摘要

As the transport artery for the reactor coolant, high-energy piping systems are the links that maintain the normal operation of each system and play a crucial role in ensuring the normal operation and safety of the reactor in nuclear power plants. During the long-term operation of the reactor, stress concentration may be induced at the weak links in the pipeline systems, such as the elbow and the tee pipe structures, under the loads of high temperature, high pressure, flow-induced vibration and so on, and finally resulting in crack defects. Due to the continuous fatigue load during the lifetime, the defects in the inner surface of the pipes may propagate rapidly and even penetrate through the wall thickness, leading to the leakage of coolant and seriously affecting the safe operation of the reactor. In order to ensure the normal function of the pipeline system and meet the service requirements, this paper studies the fatigue crack propagation problems in elbows and tee pipe in the reactor pipe systems to ensure the safe operation of the pipeline. According to the RCC-MR A16 code, the fatigue crack propagation calculation program is compiled for the elbow and tee pipe made of austenitic steel to study the fatigue crack growth process and the influencing factors of crack propagation.