Cladding flaw detection and sizing by horizontally polarized shear wave ultrasonic EMAT transducers
Experiments were carried out on the use of the EMAT technique in the ultrasonic inspection of reactor vessel cladding. The work studied the space distribution of the ultrasonic beam generated by the flexible transducers developed previously, and inspection of the cladding of the JRC-Ispra PWR vessel 1:5 scale model. Two transducer pairs were used to take measurements on the clad and unclad test block sides with the aim of studying ultrasonic beam distribution. It was found that the cladding tended to confine the beam. If, however, the wavelength was equal to or greater than the cladding thickness, the confinement was not complete and became less and less evident with increasing wavelength. It was possible to pick up echoes produced by flaws located both within the cladding and in the underlying layers. The PWR vessel model cladding was then inspected in the neighbourhood of the welds, and a large number of flaws was found. The EMAT technique has proved to be suitable for the detection and rough location of flaws but less so for their sizing, although in some cases it was possible to assess the distance between the flaw and the cladding top.
Bibliographic Reference: EUR 13036 EN (1990) 54 pp., FS, ECU 5
ISBN: ISBN 92-826-1652-5
Record Number: 199110478 / Last updated on: 1994-12-02
Original language: en
Available languages: en