Measurement of defect size and location of wall thinned pipe using ESPI and Shearography

To keep the safety of the nuclear reactor and prevent the destruction of the environment, it is important to evaluate integrity of piping used in the nuclear power plant. Many kinds of the non-destructive testing methods for the nuclear components have been developed. Especially, measurement techniques using laser provide the high accuracy, the high speed, and the convenience. ESPI and shearography are well known techniques as the optic-based non-destructive measurement method. The goal of this paper is to present the standard of measurement technique using laser for the wall-thinned pipes. In order to achieve this goal, the out-of-plane deformation of the wall-thinned pipes is quantitatively measured by using ESPI and shearography and the results are compared each other. Various kinds of specimen which have respect to the minimum thickness, the width, and the length of a wall-thinning defect are prepared. The size and the shape of a wall-thinning defect are measured by using ESPI and shearography. According to the comparison results, the applicability for the piping used in the nuclear power plant is verified and the measurable range is analyzed.