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Furusawa, Akinori; Nishimura, Akihiko; Takenaka, Yusuke; Muramatsu, Toshiharu
Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05
The aim of this work presented here is to demonstrate the potential of our method for remote controllable systematization, of testing reinforced concrete based on ultrasonic guided-wave on rebar. In order to investigate how the deteriorated phenomena has the effects on the ultrasonic guided-wave propagating on the rebar, following experiments are conducted. Test pieces used for the experiments are made of bare steel rod and cylindrically pored mortar to be representing the actual reinforced concrete. Irradiating the end face of the rod with nanosecond pulsed laser makes the ultrasonic guided-wave induced, at the other end face, the guided wave signal is measured with ultrasonic receiver. One test piece is with no damage and the other is deteriorated test piece. The deterioration is made by electrolytic corroded method. The guided-wave signal from the deteriorated test piece is measured with respect to each energization time, the change in the waveform is investigated. Analyzing the results from the experiments above, it is found that the deterioration of rebar has remarkable effects on the guided-wave signal. The signal from test piece with no damage has strong peak at both specific frequency and lower region, on the other hand, signals from deteriorated test piece has only at the specific frequency depending on the diameter of the steel rod. Finally, discussion concerning with the experimental results and future perspective for remote controllable systematization of our method is carried out.
Hoken Butsuri, 29, p.460 - 462, 1994/00
no abstracts in English
-UO fuel assemblies; ; Matsuura, Shojiro
Journal of Nuclear Science and Technology, 14(1), p.43 - 53, 1977/01
Times Cited Count：4no abstracts in English
Wakui, Takashi; Wakai, Eiichi; Naoe, Takashi; Kogawa, Hiroyuki; Haga, Katsuhiro; Takada, Hiroshi
no journal, ,
A mercury target vessel has been used for the spallation neutron source at J-PARC. It has a complicated triple-walled structure, which is assembled with thin plates (minimum thickness of 3 mm) by welding. A structural analysis of the new vessel evaluated that allowable defect size not to influence structural integrity was 0.4 mm at a highest stress region. Radiographic testing using the sample with triple-walled structure could not detect the defect within allowable detection size. On the other hand, a non-contact immersion ultrasonic method, which is insensitive to distorted surface of the vessel after welding, was able to detect the defect of 0.2 mm by using a high frequency sensor. We inspected all welding lines (total length of ca. 17 m) of newly fabricated vessel, detecting only six defects and evaluated that their sizes never influence on the structural strength. The present development of the non-destructive inspection technique has improved the reliability of the vessel.
