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Takaya, Shigeru; Nagae, Yuji; Yoshitake, Tsunemitsu; Nemoto, Yoshiyuki; Nakano, Junichi; Ueno, Fumiyoshi; Aoto, Kazumi; Tsukada, Takashi
E-Journal of Advanced Maintenance (Internet), 1(1), p.44 - 51, 2009/05
As the result of comparing the magnetic flux density and the IASCC susceptibility evaluated by SSRT test on neutron irradiated model alloys, it was shown that there is the relation without depending on dose level and chemical compositions as long as the contribution of neutron irradiation to SCC was seen. Furthermore, measuring the magnetic flux density of unirradiated simulated degraded materials indicates that not only change in chemical compositions but also some defects are needed for the magnetic flux density to increase. These results show the possibility of non-destructive estimation of susceptibility to IASCC by measuring magnetic flux density.
Tagawa, Akihiro; Fujiki, Kazunari*; Yamashita, Takuya
Proceedings of 13th International Symposium on Applied Electromagnetics and Mechanics (ISEM-13), p.243 - 244, 2007/09
Until now, in Japan, the safety of nuclear power plants (NPP) has been secured by performing a time based maintenance. However, recently, NPPs were taking into consideration a new procedure using a condition based maintenance, aiming to improve both reactors safety and reactors operation ratio. Therefore, it is needed to develop new sensors that can monitor in the same time, during reactor operation, the integrity of both piping system and pressure vessel. Two measurements techniques have been employed using a new developed sensor, depending on the required purpose. The 1st technique is based on the Pulse echo method. The 2nd technique is based on EMAR that is usually used for a material fatigue assessment. The developed sensor measures at 200 degrees C a minimum plate thickness 5mm 
0.03mm using pulse echo, and 2mm 0.003mm using EMAR.