CRACK GROWTH MONITORING BY STRAIN MEASUREMENT OF THE EXTERNAL SURFACE OF CRACKED PIPES: A FEASIBILITY STUDY
The cracks detected by in-service inspection are not always removed when they are not hazardous according to fitness-forservice evaluations. In such cases, it is important to monitor the growth of these cracks in order to assess the validity of their integrity assessment. However, due to the limitation of the accuracy of size determination by ultrasonic testing, it is difficult to know how much the cracks have grown since the previous measurement. In this study, a method for crack growth monitoring during plant operation is proposed. When a pipe is deformed elastically due to internal pressure, the strain at its external surface increases. By measuring the change in strain for the outside of the cracked pipe continuously, it is possible to determine how much the crack size changes. Elastic finite element analyses were performed for cracked pipes under internal pressure. From the analyses under various crack sizes, the accuracy and resolution of the proposed monitoring method were evaluated. It was revealed that the method could detect crack growth of less than several hundred micrometers.
Masayuki Kamaya Koji Miyoshi
Institute of Nuclear Safety System, Inc.64 Sata, Mihama-cho, Fukui 919-1205,JAPAN Institute of Nuclear Safety System, Inc.64 Sata, Mihama-cho, Fukui 919-1205, JAPAN
国际会议
18th International Conference on Nuclear Engineering(第18届国际核能工程大会 ICONE 18)
西安
英文
1-6
2010-05-17(万方平台首次上网日期,不代表论文的发表时间)