鞍形管台溶接継手における超音波探傷試験のき裂深さ測定誤差
Ultrasonic Depth-sizing Errors of Crack-like Defects in Saddle-shaped Weld Joints
著者:
福冨 広幸 Hiroyuki FUKUTOMI 林 山 Shan LIN 緒方 隆志 Takashi OGATA
発刊日:
公開日:
Boiled Water ReactorsPrimarily Loop Recirculation PipingSaddle-shaped WeldsUltrasonic Depth-sizing
概要
In order to determine crack depth in primarily loop recirculation (PLR) piping of boiling water reactors, ultrasonic angle beam testing using time of flight measurement of the diffracted signal from the crack tip, is employed. There are some power stations in Japan having saddle-shaped weld joints at branch connections in PLR piping. If the angle beam testing is applied without considering curvature of saddle-shaped weld joints, unlike weld joints of straight piping, it can be predicted that determined depth by the typical technique mentioned above contains a geometrical error due to the curvature. This issue has never been discussed in welds of branch connections. This paper deals with this issue with a mockup and phased array inspection system. As a result, the geometrical error is negligibly small in comparison to underlying depth-sizing errors of stress corrosion cracks in authentic stainless steel welds.
