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Ito, Chikara; Naito, Hiroyuki; Nishimura, Akihiko; Oba, Hironori; Wakaida, Ikuo; Sugiyama, Akira; Chiyatani, Keiji
Journal of Nuclear Science and Technology, 51(7-8), p.944 - 950, 2014/07
Times Cited Count:27 Percentile:90.9(Nuclear Science & Technology)In the Fukushima Daiichi Nuclear Power Station, it is necessary to survey the locations and conditions of fuel debris inside reactor pressure vessels or primary containment vessels under water and radiation environment in preparation for removing fuel debris. An optical fiber is well known for features such as signal transmission, light weight, superior insulation performance, water resistance and electromagnetic noise resistance. These features allow the optical fiber to simplify the instrumentation systems for in-vessel inspection, as long as provide that the optical fiber can be used under high radiation dose environment. The radiation resistance of an optical fiber was improved by increasing the amount of hydroxyl up to 1000 ppm in pure silica fiber. The improved optical fibers were irradiated with -ray up to 1 10 Gy using a Co source. They indicated a large peak around 600 nm and a peak tail from ultraviolet region, but no large absorption in infrared region except a hydroxyl absorption peak of 945 nm. We have confirmed that the optical fiber containing 1000 ppm hydroxyl has enough radiation resistance for radiation induced transmission losses and the infrared imaging is effective for observation under high radiation doses.
Ito, Chikara; Nishimura, Akihiko; Oba, Hironori; Wakaida, Ikuo; Naito, Hiroyuki; Sugiyama, Akira; Chiyatani, Keiji
no journal, ,
no abstracts in English
Ito, Chikara; Naito, Hiroyuki; Chiyatani, Keiji; Nishimura, Akihiko; Sugiyama, Akira; Oba, Hironori; Wakaida, Ikuo
no journal, ,
no abstracts in English
Ito, Chikara; Naito, Hiroyuki; Ito, Hideaki; Imaizumi, Kazuyuki; Nagai, Akinori; Ito, Keisuke; Nishimura, Akihiko; Oba, Hironori; Wakaida, Ikuo; Sugiyama, Akira; et al.
no journal, ,
no abstracts in English
Ito, Chikara; Nishimura, Akihiko; Oba, Hironori; Wakaida, Ikuo; Naito, Hiroyuki; Sugiyama, Akira; Chiyatani, Keiji
no journal, ,
no abstracts in English
Chiyatani, Keiji
no journal, ,
Japan Atomic Energy Agency (JAEA) established Collaborative Laboratories for Advanced Decommissioning Science (CLADS) in 2015. The main roles of JAEA/CLADS are to promote research and development (R&D) and human resource development towards the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F) of Tokyo Electric Power Company Holdings through collaborative efforts with academia-industry- government. Current R&D activities on risk reduction in decommissioning, accident progression evaluation and fuel debris characterization, remote system and sensing technology, and radioactive waste management for the decommissioning of the 1F are introduced.