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Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Karino, Takahiro; Shibata, Takuya; Taira, Takunori*; Wakaida, Ikuo
Journal of Nuclear Science and Technology, 61(8), p.1109 - 1116, 2024/08
Times Cited Count：1 Percentile：30.19(Nuclear Science & Technology)Oba, Hironori; Wakaida, Ikuo; Taira, Takunori*
Sumato Purosesu Gakkai-Shi, 13(2), p.51 - 58, 2024/03
no abstracts in English
Koyama, Shinichi; Ikeuchi, Hirotomo; Mitsugi, Takeshi; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Tsai, T.-H.; Takano, Masahide; Fukaya, Hiroyuki; Nakamura, Satoshi; et al.
Hairo, Osensui, Shorisui Taisaku Jigyo Jimukyoku Homu Peji (Internet), 216 Pages, 2023/11
In FY 2021 and 2022, JAEA perfomed the subsidy program for "the Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy, Thermal Bahavior Estimation, and Simplified Analysis of Fuel Debris)" started in FY 2021. This presentation material summarized the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning, Contaminated Water and Treated Water Management.
Tamura, Koji; Oba, Hironori; Saeki, Morihisa; Taguchi, Tomitsugu*; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo
Journal of Nuclear Science and Technology, 58(4), p.405 - 415, 2021/04
Times Cited Count：15 Percentile：83.18(Nuclear Science & Technology)Radiation dose rate effects on the properties of a compact fiber-optic laser-induced breakdown spectroscopy (LIBS) system with a monolithic Nd:YAG/Cr:YAG composite ceramics were investigated for remote analysis in hazardous environment. To investigate radiation effects on the LIBS signal, properties related to the Nd:YAG laser operation such as oscillation threshold, output energy, oscillation timing, temporal pulse shape, and beam profile were measured as a function of the radiation dose rate from 0 to 10 kGy/hr in view of their influences to the signal. LIBS spectra of zirconium metal were measured under irradiation. Although signal intensity decreased considerably by irradiation, informative spectra were well obtained even at the maximum radiation dose rate. From the comparison of the LIBS-related parameters among the laser properties, signal reduction was mainly ascribed to the pulse energy reduction. Scintillation emission spectra were also measured from the ceramics during the irradiation, where the signal intensity increased linearly with the dose rate. The results show that the developed system.
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Miyabe, Masabumi; Oba, Masaki; Matsumoto, Ayumu*; Sakka, Tetsuo*; Taira, Takunori*; Ikeda, Yuji*
no journal, ,
Wakaida, Ikuo; Sakka, Tetsuo*; Ikeda, Yuji*; Oba, Hironori*; Taira, Takunori*
no journal, ,
no abstracts in English
Wakaida, Ikuo; Oba, Hironori; Oba, Hironori*; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*
no journal, ,
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Taira, Takunori*; Sakamoto, Kan*; Ikeda, Yuji*
no journal, ,
no abstracts in English
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Eto, Yoshinori*; Ikeda, Yuji*; Taira, Takunori*
no journal, ,
no abstracts in English
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; Miyabe, Masabumi; Akaoka, Katsuaki; Tamura, Koji; Saeki, Morihisa; Oba, Masaki; Shibata, Takuya; Ikeda, Yuji*; Sakka, Tetsuo*; et al.
no journal, ,
Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa; Nakanishi, Ryuzo; Ikeda, Yuji*; Sakka, Tetsuo*; et al.
no journal, ,
no abstracts in English
Wakaida, Ikuo; Oba, Hironori; Taira, Takunori*; Ikeda, Yuji*
no journal, ,
no abstracts in English
Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*
no journal, ,
Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Wakaida, Ikuo; Tamura, Koji*; Nakanishi, Ryuzo*; Sakamoto, Kan*; Taira, Takunori*
no journal, ,
Development of remote inspection and elemental analysis methods in a harsh radiation environment is required, such as inspection of the nuclear fuel debris at the bottom of the post-accident nuclear reactor (Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant). Laser-induced breakdown spectroscopy (LIBS) has been utilized as an effective qualitative and quantitative analytical method for elemental analysis. Inspecting the damaged reactor vessels requires a longer fiber-optic (FO) cable, which significantly attenuates the delivered laser energy by absorption and scattering in the fiber. We report on the first trial of our FO-LIBS system using the microchip laser (MCL) to identify and quantify elements in surrogate nuclear fuel debris under gamma irradiation, the results of trials on surrogate debris analysis, containing uranium oxide, using the MCL, and the results of 100 m-long fiber-delivered LIBS.
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.
Ochi, Yoshihiro; Okada, Hajime; Nagashima, Keisuke; Kosuge, Atsushi; Tanaka, Momoko; Kiriyama, Hiromitsu; Mori, Michiaki; Yoshida, Fumiko; Kong, W.*; Taira, Takunori*
no journal, ,
At Kansai Photon Science Institute, we develop new laser system using Yb:YAG thin-disk as a driver for generating intense THz wave. Specifications of the laser are 1030 nm in wavelength, 1 kHz repetition, 1 ps duration, and 100 mJ in energy, respectively. The laser system consists of two amplifiers; the first is regenerative amplifier and the second is multi-pass amplifier. At the conference, I will present the current status of the regenerative amplifier.
Wakaida, Ikuo; Akaoka, Katsuaki; Oba, Masaki; Oba, Hironori; Tamura, Koji; Saeki, Morihisa; Matsumoto, Ayumu*; Sakka, Tetsuo*; Ikeda, Yuji*; Taira, Takunori*
no journal, ,
no abstracts in English
