High-Frequency Ultrasonic Characterization of ZrO2 Layer Thicknesses Using Digital Spectral Analysis
Embrittlement of Zr−2.5%Nb pressure tubes from CANDU nuclear reactors has recently become a concern in the Canadian nuclear industry. While a full understanding of the mechanisms involved has not yet been achieved, it is known that hydrogen/deuterium, liberated through oxidization of the tube’s inner surface, is absorbed into the metal where it eventually precipitates out as weak, brittle hydride platelets. Knowledge of the nature and extent of oxide formation may thus give indications about the degree of hydrogen uptake and embrittlement in the tubes. In particular, a reliable, nondestructive technique for determining the thickness and integrity of these oxide layers is needed. Theoretically, such an evaluation is possible using ultrasonic spectroscopy.
KeywordsReflection Coefficient Acoustic Impedance Pressure Tube Magnitude Spectrum Ontario Hydro
Unable to display preview. Download preview PDF.
- 1.L. Paradis, R. Saglio and Y. Serruys, “Ultrasonic Signal Processing for Thickness Measurement and Detection of Near-Surface Defects”, Materials Evaluation 44, Oct. 1986.Google Scholar
- 2.C. J. Bell, N. F. Haynes and P. J. McIntyre, “The Application of Broadband Ultrasonic Spectroscopy to the Study of Layered Media”, J. Acoust. Soc. Am., vol. 64, no. 1, pp 1645–51, Dec. 1978.Google Scholar
- 3.G. S. Kino, Acoustic Waves: Devices, Imaging and Analog Signal Processing, (Prentice-Hall, Englewood, New Jersey, 1987 ).Google Scholar