CHARACTERIZATION OF ZIRCONIUM HYDRIDE ORIENTATIONS IN ZIRCALOY CLADDING TUBES WITH A LASER ULTRASOUND TECHNIQUE

This research is focused on characterizing Zircaloy cladding tubes with different concentration ratios between radially(R) orientated hydrides and circumferential(C) ones. A procedure corporate with an experimental technique and an inversion algorism is used to investigate the effects of R/C ratio on the dispersion spectra of GW. A laser ultrasound technique (LUT) is used to measure the dispersions of circumferentially guided waves (CGW) propagating along the circumferential direction of the cladding tubes. An inversion algorism based on simplex method is used to extract interested properties from the measured GW dispersion spectra. It is shown that the procedure introduced in the current research is able to relate the phase velocities with hydrogen concentration. In the meanwhile, this procedure is able to distinguish the R/C ratio in a quantitative way as well. It is also found out that the bulk elastic modulus increases as the R/C ratio increases.