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Takaya, Shigeru; Yamagata, Ichiro; Ichikawa, Shoichi; Nagae, Yuji; Aoto, Kazumi
International Journal of Applied Electromagnetics and Mechanics, 33(3-4), p.1335 - 1342, 2010/10
Times Cited Count：8 Percentile：45.71(Engineering, Electrical & Electronic)We newly developed a vibrating sample magnetometer (VSM) for neutron irradiated materials to investigate the relationship between neutron irradiation damage and magnetic property. The magnetization curves of type 316 stainless steels irradiated in a fast reactor JOYO, a light water reactor JRR-3M or both of them were measured. The ranges of dose and He content were about 0.1-1.8 dpa and 0.5-35 appm, respectively. As the result, it was revealed that the magnetization at 5 kOe increases monotonously with dose regardless of He content. This result shows the possibility of nondestructive evaluation of dose of structural materials by VSM measurement of surveillance samples.
Oikawa, Ryota*; Uchimoto, Tetsuya*; Takagi, Toshiyuki*; Urayama, Ryoichi*; Nemoto, Yoshiyuki; Takaya, Shigeru; Keyakida, Satoshi*
International Journal of Applied Electromagnetics and Mechanics, 33(3-4), p.1303 - 1308, 2010/10
Times Cited Count：5 Percentile：35(Engineering, Electrical & Electronic)This paper discusses feasibility of non-linear eddy current method to evaluate material degradations of austenitic stainless steels associated with irradiation assisted stress corrosion cracking (IASCC). For the purpose, tensile test at elevated temperature was conducted using model alloys simulating radiation induced segregation (RIS), then magnetization curve of the specimens was measured by vibrating sample magnetometer (VSM), and microstructure of magnetization was observed by magnetic force microscopy (MFM). Moreover non-linear eddy current method was carried out. It was shown that the 3rd higher harmonic ration of the pick-up signal would relate to nominal strain of the specimens.
Mihalache, O.; Yamaguchi, Toshihiko; Ueda, Masashi; Miyahara, Shinya
International Journal of Applied Electromagnetics and Mechanics, 33(3-4), 6 Pages, 2010/00
In FBR, one of the techniques used in the ISI of magnetic steam generator (SG) tubes is the remote field eddy current technique (RF-ECT). The SG tubes, made of 2.25Cr-1Mo alloy, are very long, including several parts with helical, bent and straight shape. The longer parts of these tubes are fixed in a helical shape-structure using multiple support plates (SP) which are also ferromagnetic. The complicated shape of the SP and multiple connections of several tubes to the SP can be quantitatively analyzed only by a 3-dimensional analysis, in order to evaluate the influences in the ECT signal due to the close proximity of the SG tubes. Also, the tube curvature and additionally the presence of sodium on the outer tube surface induces supplementary effects. The paper presents 3D finite element simulations of the SG inspection using RF-ECT. It is evaluated the influences of the SG tubes curvature on the eddy current sensor signal.
Tagawa, Akihiro; Fujiki, Kazunari; Kojima, Fumio*
Proceedings of 14th International Symposium on Applied Electromagnetics and Mechanics (ISEM 2009), p.207 - 208, 2009/09
In the paper it was also investigated the defect detection using the electromagnetic acoustic transducer (EMAT). However, EMAT needs a different processing of defect detection signal. Until now, it was studied a small one EMAT unit that has a non-couplant characteristic and uses additionally mechanical scanning to detect defects. In the present paper it is investigated one EMAT unit with two separate coils for transducer and receiver, that can monitor for defects without any mechanical scanning.
