高経年化配管エルボの破壊評価手法の検討

抄録

This paper evaluated a closed formed solutions of stress intensity factor K and J-integral for a flawed elbow of French Code, RSE-M, in order to introduce a flaw evaluation for aged elbows into the JSME Rules on Fitness-for-Service (JSME Rules), which have flaw evaluation procedures using K and J for only straight pipes and cylinder-shaped vessels in the current version. The stress distribution of an elbow is more complex than straight pipe and depends on not only flaw shape, flaw direction and radius/thickness but also bending radius, which may result in smaller allowable flaw size than that of a straight pipe. The authors performed K and J-integral calculation using FE analysis (FEA) focusing on an aged primary coolant pipe of PWR plant in Japan and compared with the solutions of the RSE-M code. As a result, it was confirmed that K and J solutions by the RSE-M code gave generally good result with conservativeness. Some cases of K showed large unconservative predictions by the RSE-M code and it was found that those were for the elbows with geometries out of the application range of the RSE-M code. The authors will develop a flaw evaluation for elbows with larger application range than that of the RSE-M code.