SYMPOSIA PAPER Published: 01 January 1999

Detection of Radiation Damage in Low Alloy Steel Using a Squid Sensor


The magnetic properties of A533B low alloy steel irradiated up to 3 x 1023 n/m2 in a nuclear reactor were measured using a SQUID sensor. The SQUID sensor used in the test is the type with a first-order axial gradiometer. Test specimens were irradiated to 0.5 x 1023 and 3.0 x 1023 n/m2, and then magnetized in a 0.2 T field until saturation before measurement. The specimens were put on a scanning table in a hot laboratory and the SQUID output was recorded while each specimen was gradually moved in a horizontal direction under the SQUID sensor. A superconducting magnet was used to put the test specimen under a magnetic field that changed from +0.01 T to -0.01 T to observe the relation between magnetic field intensity and coercive force (B-H curve). The B-H curve shows a definite tendency towards a higher coercive force for test specimens with higher neutron fluence. The test result also shows a good relation between mechanical properties, such as yield strength, tensile strength, and the Charpy impact test result, with SQUID output. This proves that there is a very good chance of developing a non-destructive evaluation system for nuclear reactor structure. This kind of evaluation system would be a great help in making plant life management even more reliable and reasonable.

Author Information

Otaka, M
Mechanical Engineering Research Laboratory, Hitachi Ltd., Ibaraki, Japan
Shimizu, S
Hitachi Works, Hitachi Ltd., Ibaraki, Japan
Morinaka, R
Hitachi Works, Hitachi Ltd., Ibaraki, Japan
Maeda, N
JAPEIC Research Center, Japan Power Engineering and Inspection Corporation, Yokohama, Japan
Yamaguchi, A
JAPEIC Research Center, Japan Power Engineering and Inspection Corporation, Yokohama, Japan
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Developed by Committee: E10
Pages: 568–575
DOI: 10.1520/STP13888S
ISBN-EB: 978-0-8031-5395-0
ISBN-13: 978-0-8031-2614-5