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Nondestructive testing of the inner near-surface zones of nozzles, vessels and pipes from the outside

: Höller, P.; Hübschen, G.; Salzburger, H.J.

Nuclear Engineering and Design 87 (1985), pp.193-205
ISSN: 0029-5493
Journal Article
Fraunhofer IZFP ()

The most critical defects in pressure conducting components of nuclear power plants are cracklike defects at the inner surface of vessels, nozzles and pipes. This paper presents methods of testing the inner surfaces and the inner near-surface zones from the outside. Beside radiographic and radiometric methods the main point of this contribution treats ultrasonic testing methods. Especially results for testing the inner near-surface zones with electromagnetically excited SH-waves from the outside are presented. Using SH-waves the following phenomena contribute to an improvement of the testing quality: - nearly total transmission of the sound pressure at the interfaces base metal-weld metal in a wide angle range; - complete corner reflection; - small disturbing signals from roots and crowns of butt welds in thin-walled pipes when using the first symmetrical mode of guided SH-plate waves; - access of the inner radius of nozzles unaccessible with conventional ultrasonic methods.