Electromagnetic acoustic transducer (EMAT) defect characterization of nuclear reactor piping welds. Phase I. Final report, October 1985-March 1986
The Phase I workscope was successfully completed. This work was directed at determining the most promising methods for application of EMATs to stainless steel piping examination. It consisted of a literature review, evaluation of shear and longitudinal wave inspection modes, and evaluation of several signal processing techniques to enhance signal/noise ratios. The work involved both hardware and software development. A high degree of success was obtained during the course of the work, indicating that further exploitation of the technique is fully warranted. Defects as small as 0.1 cm deep could be detected in wrought stainless piping, and the ability to detect defects in thick centrifugally cast stainless samples was demonstrated. In addition, the techniques showed promise for sizing the flaws. These results were achieved through a combination of synthetic aperture processing, temporal averaging and low frequency illumination. Additional techniques were evaluated, including frequency analysis, angle beam scanning and multimode inspection, but were shown to be of limited benefit for the samples available in Phase I. However, these techniques may offer potential for discriminating between cracks and geometric reflectors. 56 refs., 21 figs.
- Research Organization:
- Sigma Research, Inc., Redmond, WA (USA). Seattle Div.
- OSTI ID:
- 5568057
- Report Number(s):
- NUREG/CR-4631; ON: TI86901453
- Country of Publication:
- United States
- Language:
- English
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