Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2022-060, 91 Pages, 2023/02
JAEA-Review-2022-060.pdf:3.95MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Challenge to investigation of fuel debris in RPV by an advanced Super Dragon articulated robot arm" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. Through this research from FY2019 to FY2021, we will closely cooperate with each research item under the principal investigator as well as with CLADS, etc., to advance the research while exchanging opinions/information with the site and promote the research implementation plan in order to apply the technology to the actual equipment at the 1F site. Meetings and conferences were held to promote the research implementation plan, with the aim of realizing a technology …
Collaborative Laboratories for Advanced Decommissioning Science; i-lab*
JAEA-Review 2022-042, 67 Pages, 2023/01
JAEA-Review-2022-042.pdf:7.42MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Challenge to advancement of debris composition and direct isotope measurement by microwave-enhanced LIBS" conducted in FY2021. The present study aims to increase the emission intensity of LIBS (laser-induced breakdown spectroscopy) by superimposing MW (microwave) and apply it to uranium isotope measurement. In FY2021, after confirming that there was no problem in terms of specifications including noise leakage by downsizing the semiconductor MW oscillator and evaluating it as a single unit, the possibility of uranium isotope measurement was examined by applying it to the LIBS experiment. In addition, the optimized design of the MW antenna was carried out. By applying them, we confirmed the actual performance, …
Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2021-045, 65 Pages, 2022/01
JAEA-Review-2021-045.pdf:3.41MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Challenge to investigation of fuel debris in RPV by an advanced super dragon articulated robot arm" conducted in FY2020. The present study aims to develop the implementation techniques of the remote sensing method on a robot arm for monitoring the structure status in the reactor and the distribution of nuclear materials by a long-articulated robot arm with controlling and grasping the position and posture of the robot arm hand. In FY 2020, we have conducted fundamental operation check of the robot arm in the simulated environment, prototype construction of telescopic articulated arm and cable storage mechanism, investigation of drive wire specifications, improvement of LIBS probe, prototype construction …
Collaborative Laboratories for Advanced Decommissioning Science; i-lab*
JAEA-Review 2021-027, 62 Pages, 2021/11
JAEA-Review-2021-027.pdf:3.06MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Challenge to advancement of debris composition and direct isotope measurement by microwave-enhanced LIBS" conducted in FY2020. Although LIBS (laser-induced breakdown spectroscopy) is commercially available for application to remote composition measurement, it is not suitable for high radiation environment due to loss in optical fibers derived from the influence of radiation, reduction in laser transmission output, and nuclear fuel debris properties. There are general concerns of the signal strength decrease. In addition, since LIBS is generally considered to be unsuitable for isotope measurement, there are problems to be improved.
Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2020-040, 55 Pages, 2021/01
JAEA-Review-2020-040.pdf:3.95MB
JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2019, this report summarizes the research results of the "Challenge to Investigation of Fuel Debris in RPV by an Advanced Super Dragon Articulated Robot Arm" conducted in FY2019.
Akaoka, Katsuaki; Oba, Masaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo
JAEA-Research 2020-001, 142 Pages, 2020/03
JAEA-Research-2020-001.pdf:4.0MB
Laser Induced Breakdown Spectroscopy (LIBS) method is an attractive technique because real-time, in-situ and remote elemental analysis is possible without any sample preparation. The LIBS technique can be applied for analyzing elemental composition of samples under severe environments such as the estimation of impurities in the next generation nuclear fuel material containing minor actinide (MA) and the detection of fuel debris in the post-accident nuclear core reactor of TEPCO's Fukushima Daiichi Nuclear Power Station. For applying LIBS to the analysis of nuclear fuel materials, it is indispensable to identify the emission spectrum and its intensity on impurities intermingled within complex emission spectra of matrix elements such as uranium (U) and plutonium (Pu). In the present study, an echelle spectrometer with a resolving power of 50,000 was employed to identify spectra of plutonium of wavelength ranging from 350 to 670nm. The 465 atomic spectra and 341 ionic spectra can be identified. We have confirmed that the measured wavelength of spectra is consistent with published values.
Miyabe, Masabumi; Oba, Masaki; Akaoka, Katsuaki; Kato, Masaaki*; Hasegawa, Shuichi*; Wakaida, Ikuo
Applied Physics A, 126(3), p.213_1 - 213_10, 2020/03
Times Cited Count：6 Percentile：38.95(Materials Science, Multidisciplinary)The dynamic behavior of an ablation plume in low pressure rare gas ambient was investigated with laser-induced fluorescence imaging spectroscopy for three refractory metals, i.e. titanium, zirconium and hafnium. A comparison of the plume expansion behaviors for the species of these elements revealed an atomic weight effect on the plume structure formation. A hemispherical thin layer and cavity structure reported previously for gadolinium were observed also for these elements. It was found that the plume size increases as well as the layer thickness decreases with increasing atomic weight. For ground state atoms of Ti, substantial amount of atoms were observed even at the center of the plume. Also, the persistence of the Ti atomic plume was as long as 300 
s, which was significantly longer than the other species studied. Furthermore, the mass-dependent elemental separation was observed in the ablation plume produced from a multielement sample. These results suggest that the observed plume structure arises from the ion-electron recombination process and the recoil of the ablated species during the multiple collisions with gas atoms.
Wakaida, Ikuo; Hasegawa, Shuichi*; Tadokoro, Takahiro*
Nihon Kikai Gakkai-Shi, 122(1211), p.18 - 20, 2019/10
no abstracts in English
Abe, Yuta; Otaka, Masahiko; Okazaki, Kodai*; Kawakami, Tomohiko*; Nakagiri, Toshio
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 7 Pages, 2019/05
Since the hardness of fuel debris containing boride from B
C pellet in control rod is estimated to be two times higher as that of oxide, such as UO
and ZrO, it is necessary to select the efficient and appropriate operation for removal of fuel debris formed in the severe accident of nuclear power plants. We focused on the characteristics of LIBS, an innovative rapid chemical in-situ analysis technology that enables simultaneous detection of B, O, and other metal elements in fuel debris. Simulated solidified melt specimens were obtained in the plasma heating tests (CMMR-0/-2, performed by JAEA) of simulated fuel assembly (ZrO is used to simulated UO pellet, other materials such as stainless steel, BC are same as fuel assembly). The LIBS signals of (B/O)/Zr ratio showed good linear relationship with Vickers hardness. This technique can be also applied as in-situ assessment tool for elemental composition and Vickers hardness of metal-oxide-boride materials.
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.
Khumaeni, A.; Miyabe, Masabumi; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi; Kato, Masaaki; Otobe, Haruyoshi; Oba, Hironori; Khumaeni, A.
no journal, ,
In Japan Atomic Energy Agency (JAEA), research and development of quick analysis for next-generation MOX fuel without chemical analysis and neutron measurement had been carried out as the entrusted project by MEXT, and basic performances by using un-irradiated MOX fuel were demonstrated. In elemental analysis by Laser Induced Breakdown Spectroscopy (LIBS) with high resolution spectrometer, relative error of 2.9% at 30% Pu and the detection lower limit of 2,500 ppm in U oxide were demonstrated with the operation time of 5 min.. In isotope ratio analysis by Ablation Resonance Absorption Spectroscopy, tunable semiconductor laser system was constructed, and the relative deviation less than 1% in the ratio of 
Pu/
Pu and sensitivity of 30-100 ppm in U were also accomplished within 5min. operation. As for an analysis in liquid sample, ultra-thin laminate flow was experimented as LIBS target, and the sensitivity comparable to conventional ICP-AES was confirmed.
Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi; Khumaeni, A.; Oba, Hironori; Ito, Chikara
no journal, ,
In the new concept of next generation nuclear fuel cycle for long lived radioactive waste disposal by use of Accelerator Driven Subcritical reactor (ADS Cycle) and by a fast breeder reactor (FBR Cycle), utilization of low-decontaminated fuel with TRU will be promoted. Simultaneous analysis of element and isotope by the combination of Laser Induced Breakdown Spectroscopy (LIBS) and Ablation Resonance Absorption Spectroscopy was demonstrated by MOX fuel. For elemental analysis, detection lower limit of 1000 ppm of Pu in U oxide and relative error under 5% have been obtained within 5 min. For isotope analysis, Pu and Pu have been observed separately, and detection lower limit of several 10 ppm and error under 1% have been accomplished. A simple antenna coupled microwave assisted LIBS was performed and the enhancement of emission intensity of several 10 times was demonstrated. For liquid sample, ultra-thin laminate flow as the laser focused target was accomplished high sensitivity of ppb. For in-situ monitoring, Optical Fiber LIBS Probe by radiation resistant optical fiber is under construction.
Akaoka, Katsuaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo
no journal, ,
no abstracts in English
Miyabe, Masabumi; Oba, Masaki; Akaoka, Katsuaki; Kato, Masaaki; Wakaida, Ikuo
no journal, ,
no abstracts in English
Akaoka, Katsuaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo
no journal, ,
no abstracts in English
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.
Akaoka, Katsuaki; Oba, Hironori; Otobe, Haruyoshi; Oba, Masaki; Miyabe, Masabumi; Wakaida, Ikuo
no journal, ,
For analysis of fuel debris in Fukushima Daiichi Nuclear Power Station, the emission spectra for uranium and plutonium by laser-induced breakdown spectroscopy were measured. The spectra through the irradiated fiber of 
ray was simulated.
Ruas, A.; Oba, Hironori; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
Akaoka, Katsuaki; Oba, Masaki; Miyabe, Masabumi; Wakaida, Ikuo
no journal, ,
For quantitative analysis of the fuel debris using Laser Induced Breakdown Spectroscopy (LIBS), great deal of analysis and identification of spectra are necessary. Therefore, we tried "the analysis of the LIBS spectrum by the least-squares method" as quantitative analysis without identification and analysis of the spectra. As a result, the calibration curves for quantitative analysis could be got without them.
