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Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Karino, Takahiro; Shibata, Takuya; Taira, Takunori*; Wakaida, Ikuo
Journal of Nuclear Science and Technology, 8 Pages, 2024/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Masaki; Ito, Chikara; Saeki, Morihisa; Kato, Masaaki
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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; Oba, Masaki; Ito, Chikara; Kato, Masaaki
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Laser Induced Breakdown Spectroscopy (LIBS) for elemental analysis and Laser Ablation Resonance Absorption Spectroscopy (LARAS) for isotope analysis have been developed as an analytical technique for Low-decontaminated MOX fuel with fissionable Miner Actinide elements (MA) and as for one of the diagnostic tool of nuclear fuel debris and polluted materials in the decommissioning of the severe accident nuclear power station. Specialized glove box with auto and remote arraignment system for LIBS and LARAS was constructed, and the detection limit of Pu in MOX to be several 1000 ppm and some hyper fine structures of 
Pu were demonstrated. For the diagnostic tool in the decommissioning of damaged core, optical fiber based portable LIBS probe made by radiation resistant optical fiber is under construction, and just now, some specific spectra from the simulated sample of molten debris made by sintered oxide of Zr and U is successfully observed under water condition or strong radiation field.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Saeki, Morihisa; Oba, Masaki; Ito, Chikara; Kato, Masaaki
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Wakaida, Ikuo; Oba, Hironori; Oba, Masaki; Matsumoto, Ayumu; Ruas, A.; Toshimitsu, Masaaki; Akaoka, Katsuaki; Miyabe, Masabumi
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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*
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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*
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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*
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Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Tamura, Koji; Saeki, Morihisa; Oba, Masaki; Shibata, Takuya; Ikeda, Yuji*; Sakka, Tetsuo*; et al.
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Wakaida, Ikuo; Oba, Hironori; Nakanishi, Ryuzo; Akaoka, Katsuaki; Shibata, Takuya
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Wakaida, Ikuo; Oba, Hironori; Nakanishi, Ryuzo; Akaoka, Katsuaki; Shibata, Takuya
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Wakaida, Ikuo; Oba, Hironori; Nakanishi, Ryuzo; Akaoka, Katsuaki; Shibata, Takuya; Karino, Takahiro
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Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Nakanishi, Ryuzo; Shibata, Takuya; Karino, Takahiro
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Wakaida, Ikuo; Oba, Hironori; Oba, Hironori*; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*
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Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Sakamoto, Kan*; Nakanishi, Ryuzo*; Kashiwakura, Shunsuke*; Taira, Takunori*; Ikeda, Yuji*; Deguchi, Yoshihiro*
no journal, ,
We are developing remote in-situ analysis by laser induced breakdown spectroscopy (LIBS) for simple in-situ screening analysis of fuel debris in the decommissioning of the Fukushima Daiichi Nuclear Power Station. For various application scenarios, microchip laser based LIBS for ultra-long distance analysis, microwave assisted LIBS for signal enhancement, and long/short double pulse laser LIBS for water-containing samples are developing as the fiber-optic LIBS system. To have the reliability, valuation with nuclear fuel materials and spent fuel, and radiation resistance test by 
Co irradiation will be planed. As a challenging trial, a development of Machine learning technique has introduced for automatically analysis of LIBS spectra.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*
no journal, ,
For the safe and efficient decommissioning of Fukushima Daiichi Nuclear Power Station, development of in-situ remote analysis of nuclear fuel debris under extreme high radiation environment has been indispensable. Optical Fiber Coupled Laser Induced Breakdown Spectroscopy (OFC-LIBS) has been developed and performed up to delivery length about 50m. For more longer delivery length, "TILA" has been developed as a laser built-in remote LIBS probe and enable radiation hardened ultra-long remote analysis of 100m. In the presentation, performance of analysis and radiation hardness will be discussed.
