LASER-ULTRASONIC TESTING AND ITS APPLICATIONS TO NUCLEAR REACTOR INTERNALS
- Power and Industrial Sys. R and D Center, Toshiba Corp., 8, Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa 235-8523 (Japan)
- Isogo Nuclear Engineering Center, Toshiba Corp., 8, Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa 235-8523 (Japan)
A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.
- OSTI ID:
- 21210234
- Journal Information:
- AIP Conference Proceedings, Vol. 975, Issue 1; Conference: 34. annual review of progress in quantitative nondestructive evaluation, Golden, CO (United States), 22-27 Jul 2007; Other Information: DOI: 10.1063/1.2902663; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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