超音波計測による核燃料被覆管の酸化減肉量の評価

抄録

The purpose of this study is to develop an ultrasonic method for measuring the actual thickness of zircaloy-2 alloy tube with the thin surface oxide layer using a high frequency broadband foccused transducer which can produce a short-duration echo.
The main algorithm of signal processing technique for thickness measurements deals with the problem for separating of echoes very close to each other and calculating of the propagation time between these two echoes by using the cross-correlation method. A computer-implemented ultrasonic method based on this algorithm was established in this study. The results of thickness measurement in metal-wall of zircaloy tubes which were artificially plasma-sprayed with ZrO₂ were presented. The comparision of ultrasonically measured thickness with the metallographically determined ones showed that the proposed method has a reasonable accuracy for the measurements of actual thin metal-wall thickness in the oxided zircaloy tubes.