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Kazama, Hiroyuki; Konashi, Kenji*; Suzuki, Tatsuya*; Koyama, Shinichi; Maeda, Koji; Sekio, Yoshihiro; Onishi, Takashi; Abe, Chikage*; Shikamori, Yasuyuki*; Nagai, Yasuyoshi*
Journal of Analytical Atomic Spectrometry, 38(8), p.1676 - 1681, 2023/07
Times Cited Count:1 Percentile:0.02(Chemistry, Analytical)Nemoto, Takahiro; Arakawa, Ryoki; Kawakami, Satoru; Nagasumi, Satoru; Yokoyama, Keisuke; Watanabe, Masashi; Onishi, Takashi; Kawamoto, Taiki; Furusawa, Takayuki; Inoi, Hiroyuki; et al.
JAEA-Technology 2023-005, 33 Pages, 2023/05
During shut down of the HTTR (High Temperature engineering Test Reactor) RS-14 cycle, an increasing trend of filter differential pressure for the helium gas circulator was observed. In order to investigate this phenomenon, the blower of the primary helium purification system was disassembled and inspected. As a result, it is clear that the silicon oil mist entered into the primary coolant due to the deterioration of the charcoal filter performance. The replacement and further investigation of the filter are planning to prevent the reoccurrence of the same phenomenon in the future.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.
JAEA-Review 2021-020, 42 Pages, 2021/10
The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.
Koyama, Shinichi; Nakagiri, Toshio; Osaka, Masahiko; Yoshida, Hiroyuki; Kurata, Masaki; Ikeuchi, Hirotomo; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Takano, Masahide; et al.
Hairo, Osensui Taisaku jigyo jimukyoku Homu Peji (Internet), 144 Pages, 2021/08
JAEA performed 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 and Thermal Behavior Estimation of Fuel Debris))" in 2020JFY. This presentation summarized briefly the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning and Contaminated Water Management.
Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Murakami, Hiroaki; Sasao, Eiji
JAEA-Research 2015-017, 54 Pages, 2015/12
This report is concerned with research to reconstruct more realistic near-field (NF) concept for the geological disposal of radioactive waste. This year is the final year of this committee activities. So we have carried out the summary on Re-thinking of NF concept and its technical basis. Cooperation between the study fields and combination of various science and technology and evaluation methods are one of the important technical bases of NF concept. In addition, since the "Great East Japan Earthquake 2011", the safety paradigm has shifted dramatically. In the reconstruction of realistic NF concept, it is necessary to analyze what security matters whether society has become unacceptable for geological disposal. Committee, we also exchange views on such matters and presented the direction of future research and development for geological disposal.
Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Ogata, Nobuhisa
JAEA-Research 2014-011, 43 Pages, 2014/09
This report is concerned with research to reconstruct more realistic near-field (NF) concept for the geological disposal. In previous year, we examined the realistic concept for near-field, including rock mass around the tunnel, particularly based on the nuclide migration scenario. The time-series change of the field was divided into five stages of 0 to IV through the process of geological disposal (Excavation, Operation and Post-closure). Then at each respective stage, post-closure stage in particular; we examined interaction between environmental factors and exhaustive extraction of those factors affecting the near-field, focusing on each scale-time cross-section. In the reconstruction of realistic near-field concept, it is necessary to analyze security matters are unacceptable by society, regarding geological disposal. We also exchanged views on those matters and presented the future direction of research and development for geological disposal.
Yamaoka, Shingo; Shimizu, Yuka*; Fukuda, Yoshihiro*; Shobu, Takahisa; Konishi, Hiroyuki
JAEA-Technology 2014-027, 21 Pages, 2014/08
At SPring-8 synchrotron radiation beamlines, it is essential to maintain a vacuum between the radiation source and the experimental station. This is achieved by using scroll pumps and turbo molecular pumps. However, scroll pump malfunctions have been reported at BL22XU. Since many of the pumps are located inside radiation-shielding hutches, malfunctions often go un-noticed. As a result, operations can continue despite the malfunction. To facilitate the early detection of scroll pump malfunctions, we have developed a "scroll pump operating status monitoring system (SCP-MS)". The system simultaneously measures motor current and vacuum pressure at the scroll pump. It is possible to monitor pumps from outside of the shielding hutch, something which was not possible until now. The (SCP-MS) has been installed to monitor scroll pumps in actual operation, to monitor the change of the motor current value and vacuum pressure. We report on the detail of the system.
Kobayashi, Nobuyuki*; Nakamura, Takashi*; Kondo, Yosuke*; Tostevin, J. A.*; Utsuno, Yutaka; Aoi, Nori*; Baba, Hidetada*; Barthelemy, R.*; Famiano, M. A.*; Fukuda, Naoki*; et al.
Physical Review Letters, 112(24), p.242501_1 - 242501_5, 2014/06
Times Cited Count:90 Percentile:94.35(Physics, Multidisciplinary)no abstracts in English
Nakamura, Takashi*; Kobayashi, Nobuyuki*; Kondo, Yosuke*; Sato, Yoshiteru*; Tostevin, J. A.*; Utsuno, Yutaka; Aoi, Nori*; Baba, Hidetada*; Fukuda, Naoki*; Gibelin, J.*; et al.
Physical Review Letters, 112(14), p.142501_1 - 142501_5, 2014/04
Times Cited Count:62 Percentile:91.04(Physics, Multidisciplinary)no abstracts in English
Takasaki, Koji; Yasumune, Takashi; Onishi, Takashi; Nakamura, Keisuke; Ishimi, Akihiro; Ito, Chikara; Osaka, Masahiko; Ono, Masashi*; Hatakeyama, Shuichi*; Takahashi, Hiroyuki*; et al.
JAEA-Research 2013-043, 33 Pages, 2014/01
In the Fukushima Daiichi Nuclear Power Plant, it is assumed that the core fuels melted partially or wholly, and the normal technique of accounting for a fuel assembly is not applicable. Therefore, it is necessary to develop the transparent and rational technique of accounting in the process of collection and storage of fuel debris. In this research, an application of the superconducting phase Transition Edge Sensor microcalorimeter (TES microcalorimeter) is studied for the accounting of nuclear materials in the fuel debris. It is expected that the detailed information of nuclear materials and fission products in fuel debris is obtained by using a high-resolution characteristic of TES microcalorimeter. In this report, the principle of TES microcalorimeter, the measurement experiment using TES in JAEA, and the simulated calculation using the EGS5 code system are summarized.
Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Ogata, Nobuhisa
JAEA-Research 2013-015, 21 Pages, 2013/11
This report is concerned with research to reconstruct more realistic near-field concept for the geological disposal. In chapter, we examined the realistic concept for near field, including rock around the tunnel, based on the nuclide migration scenario in particular. The time-series change of the field was divided into five stages of 0IV through the process of geological disposal (Excavation, Operation and Post-closure). Then, for each stage respectively, we examined interaction between environmental factors and extraction of those factors changing the "field". The Goal of this year is to set up the state in the realistic "field" exhaustively, by focusing on the scale-time cross-section of each stage, especially post-closure stage, and to present the assignment of the next fiscal year.
Onishi, Yuki*; Takata, Takashi*; Yamaguchi, Akira*; Uchibori, Akihiro; Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki
Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 8 Pages, 2012/12
In the steam generator of sodium-cooled fast reactor (SFR), self-wastage phenomena is a crack enlargement on the heat transfer tube itself caused by sodium-water reaction, a quantification of the self-wastage phenomenon is of importance from the viewpoint of safety assessment. In this study, we propose a numerical approach to evaluate the self-wastage phenomena and investigate a crack enlargement using SERAPHIM code. In the analysis, two-dimensional initial crack is assumed based on SWAT-4 experiment. The wastage rate was estimated by Arrhenius type equation, and re-meshing arrangement was performed by cut down from a part of tube in the initial model with the wastage amount. After simulated again using the re-meshing models, the resulting SWR products were distributed not only circumferential direction but also radial direction.
Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.
JAEA-Research 2011-033, 126 Pages, 2012/02
The next advancements for the research of radioactive waste repository was started to improve and systematize the investigation and evaluation techniques on geological environment in consideration of intra-field of science and technology. Intra-field means the various fields among each study area of (a) geological environment, (b) design and engineering, (c) safety evaluation for radioactive waste repository, here. The following items were studied and discussed this year. (1) To Reconstruct Near Field (NF) Concept in consideration of coupled phenomena on geological environment. (2) To develop systematic investigation techniques on the geological environment in consideration of intra-field among each study area above mentioned (a), (b) and (c). Regarding (1), examination of NF concept focused on the realistic crystalline rock was carried out. Also through the overall discussion in the committee, comments from the all commissioners in relation to the intra-field of their study area were made to reflect on reconstruction of NF concept. Regarding (2), the research and development in consideration of NF and intra-field among each study area were conducted.
Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.
JAEA-Research 2010-049, 282 Pages, 2011/02
This report summarizes studies that have been carried out with the aim of assessing and systemizing the technology used for the investigation and analysis of the deep underground geological environment in relation to the disposal of radioactive waste. The main studies were: (1) a study on the research and development (R&D) topics proven to have practical application for the investigation, and analysis and understanding of the deep underground geological environment, and, (2) a study on leading edge technology that can provide the advanced technical basis for the investigation, analysis and understanding of the deep underground geological environment. Regarding the R&D topics (1, above), specific investigations, measurements, numerical analyses and chemical analyses were performed and reviewed with respect to the topics, (a) Repository design, engineering technology (b) Geological environment and (c) Safety evaluation. Based on the result of the review, topics requiring collaboration research in overlapping research fields, including safety assessment, were identified. Also, the near field concept (NFC) was reconsidered in terms of its realistic construction model. Regarding advanced technology (2, above), based on the objectives of the JAEA (Japan Atomic Energy Agency) research project, the study was implemented considering previous R&D results and detailed research result at the research site and thus an assessment of the need for advanced technical basis for investigation and analysis. This study contributed to the R&D development and its practical application.
Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.
JAEA-Research 2009-055, 145 Pages, 2010/02
This report summarizes studies that were carried out with the aim of assessing and systemizing the technology used for the investigation and analysis of the deep underground geological environment in relation to the disposal of radioactive waste. The main studies were: (1) a study on the research and development (R&D) topics proven to have practical application for the investigation, analysis and understanding of the deep underground geological environment, and, (2) a study on leading edge technology that can provide the advanced technical basis for the investigation, analysis and understanding of the deep underground geological environment. The principal results obtained from the studies are as follows: Regarding the R&D topics (1, above), the specific investigations, measurements, numerical and chemical analyses were reviewed with respect to engineering technology and the geological environment in this year. Based on the results of the review, topics requiring collaboration research in overlapping research fields, including safety assessment, were identified. Also, the near field concept (NFC) was reconsidered in terms of both the generic model and for crystalline rock. Regarding advanced technology (2, above), based on the objectives of the JAEA (Japan Atomic Energy Agency) research project, the study was implemented considering previous R&D results and detailed research result at the research site and thus an assessment of the need for advanced technical basis for investigation and analysis. This study contributed to the R&D development and its practical application.
Okajima, Yuka; Matsumura, Daiju; Nishihata, Yasuo; Konishi, Hiroyuki; Mizuki, Junichiro
JAEA-Technology 2009-058, 45 Pages, 2009/12
From 2004 to 2006, the Dispersive XAFS system was constructed at JAEA beamline BL14B1 in SPring-8, and has been developed. Recently, the application of this system to materials science started. We report on the outline of this Dispersive XAFS system and explain its operations.
Nakamura, Takashi*; Kobayashi, Nobuyuki*; Kondo, Yosuke*; Sato, Yoshiteru*; Aoi, Nori*; Baba, Hidetada*; Deguchi, Shigeki*; Fukuda, Naoki*; Gibelin, J.*; Inabe, Naoto*; et al.
Physical Review Letters, 103(26), p.262501_1 - 262501_4, 2009/12
Times Cited Count:198 Percentile:97.52(Physics, Multidisciplinary)no abstracts in English
Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.
JAEA-Research 2008-099, 171 Pages, 2009/03
In this year, the following studies were carried out with the aim of systemizing the technology on the investigation and analysis to understand the deep underground geological environment in relation to the radioactive waste disposal. (1) The study on the research and development (R&D) subjects which turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis for the investigation and analysis of deep underground geological environment. The results obtained from the studies are as follows: Regarding (1), the specific investigations, measurements, numerical and chemical analyses were performed particularly for research subjects: (a) the repository design and engineering technology and (b) geological environment. Based on the results on (1), (c) tasks of collaboration research on niche area between the research fields, including the safety assessment field, were selected. Also subject's items of the NFC (Near Field Concept) redefinition were discussed. Regarding (2), based on the extraction tasks of JAEA (Japan Atomic Energy Agency) research project, the study was implemented with applying previous R&D results and detailed research at the research field was carried out. This study contributed to the R&D development for its practical application.
Rintsu, Yuko*; Serizawa, Shigeru*; Yamazaki, Tetsuo*; Umeyama, Nobuaki*; Moriuchi, Shigeru*; Handa, Hiroyuki*; Onishi, Ryoichi*; Takemura, Morio*; Chino, Masamichi; Nagai, Haruyasu; et al.
Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10
no abstracts in English