Ultrasonic Testing for IDSCC in Small Radius U-bends of Steam Generator Tubes

摘要

Ultrasonic testing of standard straight 7/8" steam generator tubes can be carried out with a number of systems. The Nerason UT system is especially developed to measure straight tubes with an ID of 10-100 mm, but is also capable of testing bended tubes. The current UT probe for small radius U-bends has limitations of a minimum bend radius of 55 mm and a tube ID of 20 mm. Also two different probes have to be used to cover the complete 360 degree of the circumference of the tube. On customer request Nuson has developed a new probe which does not have the coverage limitation and is capable of examining tubes with an ID of 15 mm. This presentation will show an overview of the probe design, the test results and the current developments that are carried out to improve the sizing capabilities.