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Tamura, Koji*; Toyama, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 62(5), p.268 - 271, 2020/05
The laser cutting technology is expected to be a promising candidate for the decommissioning measure of nuclear facilities, because it has a lot of advantage such as its high controllability and excellent suitability to remote handling by robot arm, etcetera. This report describes the recent result from laser cutting technology development for thick steel materials summarizing the cutting demonstration of 300 mm thick steels and dummy pressure vessel, the analysis of cutting condition of thick steel cutting, the observation of cutting process, remote controlled cutting system, the cutting in pile of steels by the system, and countermeasure for fume produce by cutting process.
Ito, Chikara; Naito, Hiroyuki; Ishikawa, Takashi; Ito, Keisuke; Wakaida, Ikuo
JPS Conference Proceedings (Internet), 24, p.011038_1 - 011038_6, 2019/01
A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels at the Fukushima Daiichi Nuclear Power Station. The tentative dose rate in the reactor pressure vessels is assumed to be up to 1 kGy/h. We developed a radiation resistant optical fiber consisting of a 1000 ppm hydroxyl doped pure silica core and 4 % fluorine doped pure silica cladding. We attempted to apply the optical fiber to remote imaging technique by means of fiberscope. The number of core image fibers was increased from 2000 to 22000 for practical use. The transmissive rate of infrared images was not affected after irradiation of 1 MGy. No change in the spatial resolution of the view scope by means of image fiber was noted between pre- and post-irradiation. We confirmed the applicability of the probing system, which consists of a view scope using radiation-resistant optical fibers.
Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa
Kogaku, 48(1), p.13 - 20, 2019/01
By Laser Induced Breakdown Spectroscopy and by related resonance spectroscopy, elemental and isotope analysis of Uranium and Plutonium for nuclear fuel materials and in-situ remote analysis under strong radiation condition for melt downed nuclear fuel debris at damaged core in "Fukushima Daiichi Nuclear Power Station", are introduced and performed as one of the application in atomic energy research field.
Oka, Kiyoshi
Reza Kenkyu, 31(9), p.612 - 617, 2003/09
no abstracts in English
Oka, Kiyoshi; Tada, Eisuke; Kimura, Seiichiro*; Ogawa, Tadashi*; Sasaki, Nami*
High-power Lasers in Manufacturing (Proceedings of SPIE Vol.3888), p.702 - 709, 1999/11
no abstracts in English
Oka, Kiyoshi; *; *; *; Takahashi, Hiroyuki*; Tada, Eisuke
JAERI-Tech 99-048, 222 Pages, 1999/07
no abstracts in English
Obara, Kenjiro; Kakudate, Satoshi; Nakahira, Masataka; *
J. Robot. Mechatron., 10(2), p.96 - 103, 1998/00
no abstracts in English
Yoshida, Hidetoshi; Naito, Osamu; Matoba, Toru; Yamashita, Osamu; Kitamura, Shigeru; Hatae, Takaki; Nagashima, Akira
Review of Scientific Instruments, 68(2), p.1152 - 1161, 1997/02
Times Cited Count：13 Percentile：68.1(Instruments & Instrumentation)no abstracts in English
Kihara, Takehiro; S.I.Sinkov*; Fujine, Sachio; Maeda, Mitsuru
Value Adding Through Solvent Extraction (Proc. of ISEC 96), 2, p.1603 - 1607, 1996/00
no abstracts in English
S.I.Sinkov*; Kihara, Takehiro; Fujine, Sachio; Maeda, Mitsuru
JAERI-Tech 95-016, 48 Pages, 1995/03
no abstracts in English
Kihara, Takehiro; *; Fujine, Sachio; Maeda, Mitsuru; *; *
JAERI-M 93-234, 47 Pages, 1993/12
no abstracts in English
Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Hironori; Saeki, Morihisa; Ito, Chikara; Oba, Masaki; Kato, Masaaki
no journal, ,
In the decommissioning of "Fukushima Daiichi Atomic Power Plant", it will be difficult work by the extremely high radioactivity from fission products and meltdown nuclear fuel debris. Technical innovations and some breakthrough will be indispensable for a safety accomplishment of this work. For the basic R&D on the decommissioning, Japan Atomic Energy Agency has opened the new research center "Collaborative Laboratories for Advanced Decommissioning Science". The development of onsite and in-situ analysis of fuel debris is one of the most important for the planning and working of the decommissioning. Quick, easy, non-contact, no-preparation, direct and remote analysis technique by Laser Induced Breakdown Spectroscopy (LIBS) based on radiation resistant optical fiber will be now under developing. Pulsed Nd:YAG laser will be propagated though an optical fiber and focused on the sample. Plasma emission produced by the laser on the surface of the sample is collected by the same focusing lens, propagated through the same optical fiber and put into the spectrometer. Elemental identification and the composition are evaluated by specific atomic emission line and its intensity. Under strong irradiation condition; dose rate of 10 kGy/h and after total dose of 2 MGy, radiation resistant optical fiber had good transmission, no damage by laser light propagation, and had good performance for plasma emission spectroscopy. In addition, we have successfully observed and identified the specific spectra of Zr and U from the simulated sample of molten debris made by sintered oxide of Zr and U which is the raw materials of the fuel assembly. Quantitative analysis of the composition ratio of Zr/U has been also evaluated from the intensity ratio of specific emission lines.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Masaki; Ito, Chikara; Saeki, Morihisa; Kato, Masaaki
no journal, ,
In nuclear engineering, especially for the decommissioning of severe accident atomic power plant, development of quick, easy, non-contact, no-preparation, direct, remote, onsite and in-situ analysis of nuclear fuel materials which has very complex and large amount of optical emission lines will be indispensable. In these R&D, it may be important how we realize high sensitivity and high resolution spectroscopy and perform the identification of the specific element among a large number of emission spectra. Various kind of technique, such as Double-pulse LIBS and Microwave assisted LIBS for multiply the emission intensity, high resolution LIBS by ultra-high resolution spectrometer or Laser Ablation Resonance Absorption Spectroscopy for isotope analysis, Ultra-thin Liquid flow LIBS for liquid phase application and LIBS based on radiation resistant optical fiber for onsite/in-situ monitoring of melt downed nuclear fuel debris, will have been under investigation. Japan Atomic Energy Agency has opened the new research center "Collaborative Laboratories for Advanced Decommissioning Science", and laser based spectroscopy will be restarted as one of the basic projects.
Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Hironori; Saeki, Morihisa; Ito, Chikara; Oba, Masaki; Kato, Masaaki
no journal, ,
For the decommissioning of "Fukushima Daiichi Nuclear Power Plant", development of onsite and in-situ remote diagnostic/analysis techniques under high radioactive environments will be strongly required. For the basic R&D on the decommissioning, Japan Atomic Energy Agency has opened the new research center "Collaborative Laboratories for Advanced Decommissioning Science". The concept of probing by light and diagnostic by light will be one of the powerful choices to accomplish these requirements. So, we are now developing the remote diagnostic technique for onsite, in-situ monitoring of nuclear debris. Optical Fiber based LIBS probe made by radiation resistant optical fiber was constructed, and we have successfully observed some specific spectra from the simulated sample of molten debris made by sintered oxide of Zr and U under the severe environment such as radioactive condition of 10 kGy/h and after total dose of 2 MGy.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Saeki, Morihisa; Oba, Masaki; Ito, Chikara; Kato, Masaaki
no journal, ,
Matsumoto, Ayumu; Oba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
Wakaida, Ikuo; Oba, Hironori; Oba, Masaki; Matsumoto, Ayumu; Ruas, A.; Toshimitsu, Masaaki; Akaoka, Katsuaki; Miyabe, Masabumi
no journal, ,
For the decommissioning of "Fukushima Daiichi Nuclear Power Station", Optical Fiber based LIBS probe is constructed, and under water condition, we have successfully observed some specific spectra from the simulated sample of molten debris made by sintered oxide of Zr and U. For the use of more longer optical fiber, long-pulse laser with the pulse duration about 100 ns will be introduced to compensate the delivery power loss and/or to enhance the emission signal to be about several times by the time integration of emission signal. As for the signal enhancement technique, microwave assisted LIBS technique coupled with simple antenna for the combination use with fiber LIBS will be under developing, and about ten times enhancement was observed under the atmosphere condition. For the application to the liquid phase sample, especially for the analysis of the polluted cooling water, the thin-sheet liquid jets will be also introduced as the convenience and high sensitive monitoring for dissolved elements of nuclear fuel debris.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Oba, Masaki; Matsumoto, Ayumu; Miyabe, Masabumi; Ikeda, Yuji*; Sakka, Tetsuo*; Taira, Takunori*
no journal, ,
For the decommissioning of "Fukushima Daiichi Nuclear Power Station (F1NPS)", widely basic R&D and matting for actual application for decommissioning technology will be strongly required. CLADS/JAEA is one of the key institute for strategic promotion of Decommissioning Science on F1NPS. As for the development of rapid, easy, onsite and in-situ remote diagnostic/analysis techniques under extremely high radioactive condition, the concept of probing by light and diagnostic by light with radiation resistant optical fiber will be one of the simple, powerful and applicable choices as the innovative development based on laser induced breakdown spectroscopy (LIBS) technology. Optical fiber based LIBS is developed for in-core and in-situ elemental analysis of debris and its activity is performed under severe environmental conditions such as high radiation field of about 10kGy/h and under water. Long pulse laser, microwave assisted LIBS and microchip laser are also introduced for more high sensitivity.
Wakaida, Ikuo; Oba, Hironori*; Ikeda, Yuji*; Sakka, Tetsuo*; Taira, Takunori*
no journal, ,
Radiation resistant optical fiber based laser induced breakdown spectroscopy (Fiber LIBS) is developed for in-core and in-situ elemental analysis of debris and its activity is performed under severe environmental conditions such as high radiation field of about 10kGy/h and under water. Long pulse laser, microwave assisted LIBS for more high sensitivity and micro-chip Laser will be also introduced for In-Core use optical source.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Masaki; Taira, Takunori*
no journal, ,
