TY - GEN
T1 - An ECT probe with widely spaced coils for local wall thinning in nuclear power plants
AU - Yamamoto, Toshihiro
AU - Uchimoto, Tetsuya
AU - Takagi, Toshiyuki
PY - 2011
Y1 - 2011
N2 - Currently, local wall thinning on the inner surface of a pipe is evaluated mostly by ultrasonic thickness measurement from the outer surface of the pipe in nuclear power plants in Japan. However, it has been pointed out that there are two major issues of this evaluation method. Firstly, this method is not able to evaluate local wall thinning from the top of a reinforcing plate that covers the outer surface of a pipe because this two-layer structure hinders the propagation of ultrasound. Secondly, because ultrasonic thickness measurement of a pipe wall is conducted at certain intervals on the outer surface of the pipe, it may overlook a hole-like defect if the defect size is small compared to this interval. We propose an eddy current testing (ECT) method using widely spaced excitation and pick-up coils to alleviate these problems. Our experimental results show this method can be applied to inspection of a double plate that consists of two 8 mm-thick austenitic stainless steel plates, and a defect indication is observed in a much larger area than the defect.
AB - Currently, local wall thinning on the inner surface of a pipe is evaluated mostly by ultrasonic thickness measurement from the outer surface of the pipe in nuclear power plants in Japan. However, it has been pointed out that there are two major issues of this evaluation method. Firstly, this method is not able to evaluate local wall thinning from the top of a reinforcing plate that covers the outer surface of a pipe because this two-layer structure hinders the propagation of ultrasound. Secondly, because ultrasonic thickness measurement of a pipe wall is conducted at certain intervals on the outer surface of the pipe, it may overlook a hole-like defect if the defect size is small compared to this interval. We propose an eddy current testing (ECT) method using widely spaced excitation and pick-up coils to alleviate these problems. Our experimental results show this method can be applied to inspection of a double plate that consists of two 8 mm-thick austenitic stainless steel plates, and a defect indication is observed in a much larger area than the defect.
KW - Eddy current testing
KW - Local wall thinning
KW - Pancake coil
UR - http://www.scopus.com/inward/record.url?scp=84865406365&partnerID=8YFLogxK
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U2 - 10.3233/978-1-60750-750-5-241
DO - 10.3233/978-1-60750-750-5-241
M3 - Conference contribution
AN - SCOPUS:84865406365
SN - 9781607507499
T3 - Studies in Applied Electromagnetics and Mechanics
SP - 241
EP - 248
BT - Electromagnetic Nondestructive Evaluation (XIV)
A2 - Chady, Tomasz
A2 - Gratkowski, Stanislaw
A2 - Takagi, Toshiyuki
A2 - Udpa, Satish S.
ER -