ステンレス鋳鋼の超音波伝搬解析のための基礎検討

抄録

Cast stainless steel (CASS) is widely used in primary coolant piping of nuclear power plants because of its high corrosion resistance and high strength. An in-service inspection based on ultrasonic testing (UT) has to be conducted for weld joints of primary coolant piping on the basis of JSME Rules on Fitness-for-Service for Nuclear Power Plants. However, it is difficult to detect and size flaws in CASS components with high accuracy because of the following reasons: Ultrasonic waves are scattered and attenuated due to coarse grains, and anisotropic and heterogeneous properties in CASS lead to ultrasonic beam splitting and skewing. In order to solve such problems, it is effective to simulate wave propagation in CASS. In this study, statically cast stainless steel is focused as a first step to simulate wave propagation in CASS. We applied the cellular automaton coupled finite element model to predict the microstructures of CASS and carried out wave propagation simulation taking into account microstructures predicted.