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Machida, Masahiko; Yamada, Susumu; Kim, M.; Tanaka, Satoshi*; Tobita, Yasuhiro*; Iwata, Ayako*; Aoki, Yuto; Aoki, Kazuhisa; Yanagisawa, Kenichi*; Yamaguchi, Takashi; et al.
RIST News, (70), p.3 - 22, 2024/09
Inside the Fukushima Daiichi Nuclear Power Plant (1F), there are many locations with high radiation levels due to contamination by radioactive materials that leaked from the reactor. These pose a significant obstacle to the smooth progress of decommissioning work. To help solve this issue, the Japan Atomic Energy Agency (JAEA), under a subsidy from the Ministry of Economy, Trade, and Industry's decommissioning and contaminated water management project, is conducting research and development on digital technologies to improve the radiation environment inside the decommissioning site. This project, titled "Development of Technology to Improve the Environment Inside Reactor Buildings (Enhancing Digital Technology for Environment and Source Distribution to Reduce Radiation Exposure)," began in April of FY 2023. In this project, the aim is to develop three interconnected systems: FrontEnd, Pro, and BackEnd. The FrontEnd system, based on the previously developed 3D-ADRES-Indoor (prototype) from FY 2021-2022, will be upgraded to a high-speed digital twin technology usable on-site. The Pro system will carry out detailed analysis in rooms such as the new office building at 1F, while the BackEnd system will serve as a database to centrally manage the collected and analyzed data. This report focuses on the FrontEnd system, which will be used on-site. After point cloud measurement, the system will quickly create a 3D mesh model, estimate the radiation source from dose rate measurements, and refine the position and intensity of the estimated source using recalculation techniques (re-observation instructions and re-estimation). The results of verification tests conducted on Unit 5 are also presented. Furthermore, the report briefly discusses the future research and development plans for this project.
Yamashita, Kiyoto; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2023-023, 97 Pages, 2024/03
JAEA-Technology-2023-023.pdf:8.21MB
The incinerator adopted to incineration room, Plutonium Waste Treatment Facility had been demonstrated since 2002 for developing technologies to reduce the volume of fire-resistant wastes such as vinyl chloride (represented by Polyvinyl chloride bags) and rubber gloves for Radio Isotope among radioactive solid wastes generated by the production of mixed oxide fuels. The incinerator, cooling tower, and processing pipes were replaced with a suspension period from 2018 to 2022, which fireproof materials on the inner wall of the incinerator was cracked and grown caused by hydrogen chloride generated when disposing of fire-resistant wastes. This facility consists of the waste feed process, the incineration process, the waste gas treatment process, and the ash removal process. We replaced the cooling tower in the waste gas treatment process from March 2020 to March 2021, and the incinerator in the incineration process from January 2021 to February 2022. In addition, samples were collected from the incinerator and the cooling tower during the removing and dismantling of the replaced devices, observed by Scanning Electron Microscope and X-ray microanalyzer, and analyzed by X-ray diffraction to investigate the corrosion and deterioration of them. This report describes the method of setting up the green house, the procedure for replacing them, and the results from analysis in corrosion and deterioration of the cooling tower and incinerator.
Yamashita, Kiyoto; Yokoyama, Aya*; Takagai, Yoshitaka*; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2022-020, 106 Pages, 2022/10
JAEA-Technology-2022-020.pdf:4.77MB
Radioactive solid wastes generated by Fukushima Daiichi Nuclear Power Station disaster may contain high levels of salt from the tsunami and seawater deliberately released into the area. It is assumed that polyvinyl chloride (PVC) products may be used for decommissioning work and for containment of radioactive wastes in the future. Among the method of handling them, incineration is one method that needs to be investigated as it is good method for reduction and stabilization of wastes. But in order to dispose of Trans-Uranic (TRU) solid waste containing chlorides, it is necessary to select the structure and materials of the facility based on the information such as the movement of nuclides and chlorides in the waste gas treating system and the corrosion of equipment due to chlorides. Therefore, we decided to get various data necessary to design a study of the incineration facilities. And we decided to examine the transfer behavior of chlorides to the waste gas treatment system, the corrosion-resistance of materials in the incineration facilities, and the distribution survey of plutonium in them obtained using the Plutonium-contaminated Waste Treatment Facility (PWTF), Nuclear Fuel Cycle Engineering Laboratories, which is a unique incinerating facility in Japan. This report describes the transfer behavior of chlorides in the waste gas treatment system, the evaluation of corrosion-resistance materials and the distribution survey of plutonium in the incineration facilities obtained by these tests using the Plutonium-contaminated Waste Treatment Facility, Nuclear Fuel Cycle Engineering Laboratories.
Sato, Yuji*; Tsukamoto, Masahiro*; Shobu, Takahisa; Funada, Yoshinori*; Yamashita, Yorihiro*; Hara, Takahiro*; Sengoku, Masanori*; Sakon, Yu*; Okubo, Tomomasa*; Yoshida, Minoru*; et al.
Applied Surface Science, 480, p.861 - 867, 2019/06
Times Cited Count：41 Percentile：85.79(Chemistry, Physical)Sato, Yuji*; Tsukamoto, Masahiro*; Shobu, Takahisa; Yamashita, Yoshihiro*; Yamagata, Shuto*; Nishi, Takaya*; Higashino, Ritsuko*; Okubo, Tomomasa*; Nakano, Hitoshi*; Abe, Nobuyuki*
Applied Physics A, 124(4), p.288_1 - 288_6, 2018/04
Times Cited Count：18 Percentile：61.71(Materials Science, Multidisciplinary)The dynamics of titanium (Ti) melted by laser irradiation was investigated in a synchrotron radiation experiment. As an indicator of wettability, the contact angle between a selective laser melting (SLM) baseplate and the molten Ti was measured by synchrotron X-rays at 30 keV during laser irradiation. As the baseplate temperature increased, the contact angle decreased, down to 28 degrees at a baseplate temperature of 500
C. Based on this result, the influence of wettability of a Ti plate fabricated by SLM in a vacuum was investigated. It was revealed that the improvement of wettability by preheating suppressed sputtering generation, and a surface having a small surface roughness was fabricated by SLM in a vacuum.
Ohgama, Kazuya; Ando, Yoko; Yamaguchi, Mika; Ikuta, Yuko; Shinohara, Nobuo; Murakami, Hiroyuki; Yamashita, Kiyonobu; Uesaka, Mitsuru*; Demachi, Kazuyuki*; Komiyama, Ryoichi*; et al.
JAEA-Review 2013-004, 76 Pages, 2013/05
JAEA-Review-2013-004.pdf:13.53MB
JAEA together with the Japan Nuclear Human Resource Development Network (JN-HRD Net), the University of Tokyo (UT) and the Japan Atomic Industrial Forum (JAIF) cohosted the IAEA-Nuclear Energy Management School in Tokai Village, aiming that Japan will be the center of nuclear HRD in the Asian region. In the school, not only lectures by IAEA experts, but also lectures by Japanese experts and technical visits were included for foreign participants. The school contributed to the internationalization of Japanese young professionals, development of nuclear human resource of other countries, and enhancement of cooperation between IAEA and Japan. Additionally, collaborative relationship within JN-HRD Net was strengthened by the school. In this report, findings obtained during the preparatory work and the school period are reported for future international nuclear HRD activities in Japan.
Kanamori, Masashi; Shirakawa, Yusuke; Yamashita, Toshiyuki; Okuno, Hiroshi; Terunuma, Hiroshi; Ikeda, Takeshi; Sato, Sohei; Terakado, Naoya; Nagakura, Tomohiro; Fukumoto, Masahiro; et al.
JAEA-Review 2010-037, 60 Pages, 2010/09
JAEA-Review-2010-037.pdf:3.11MB
When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) provides technical support to the National government, local governments, police, fire station and license holder etc. They are designated public organizations conforming to the basic law on emergency preparedness and the basic plan for disaster countermeasures. The Nuclear Emergency Assistance & Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an off-site center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, provides for the dispatch of specialist as required, supplies emergency equipments and materials to the national government and municipal office. NEAT provide various lectures and training course concerning nuclear disaster prevention for those personnel taking an active part in emergency response organizations at normal time. And NEAT researches on nuclear disaster prevention and also cooperate with international organizations. This annual report summarized the activities of JAEA/NEAT in the fiscal year 2009.
resolutionYagi, Daichi*; Yamada, Taro*; Kurihara, Kazuo; Onishi, Yuki*; Yamashita, Masahiro*; Tamada, Taro; Tanaka, Ichiro*; Kuroki, Ryota; Niimura, Nobuo*
Acta Crystallographica Section D, 65(9), p.892 - 899, 2009/09
Times Cited Count：17 Percentile：79.90(Biochemical Research Methods)A neutron crystallographic analysis of phosphate-free bovine pancreatic RNase A has been carried out at 1.7 resolution using the BIX-4 single-crystal diffractometer at the JRR-3 reactor of the Japan Atomic Energy Agency. The high resolution structural model allowed us to determine that His12 acts mainly as a general base in the catalytic process of RNase A. Numerous other distinctive structural features such as the hydrogen positions of methyl groups, hydroxyl groups, prolines, asparagines and glutamines were also determined at 1.7 resolution. The protonation and deprotonation states of all of the charged amino-acid residues allowed us to provide a definitive description of the hydrogen-bonding network around the active site and the H atoms of the key His48 residue. Differences in hydrogen-bond strengths for the 
-helices and 
-sheets were inferred from determination of the hydrogen-bond lengths and the H/D-exchange ratios of the backbone amide H atoms. The correlation between the B factors and hydrogen-bond lengths of the hydration water molecules was also determined.
Yagi, Masahiro; Watanabe, Masanori; Oyama, Koji; Yamamoto, Kazuyoshi; Komeda, Masao; Kashima, Yoichi; Yamashita, Kiyonobu
Applied Radiation and Isotopes, 67(7-8), p.1225 - 1229, 2009/07
Times Cited Count：11 Percentile：58.64(Chemistry, Inorganic & Nuclear)Yang, X.; Tagawa, Akihiro; Ueda, Masashi; Yamashita, Takuya; Otsuka, Yusuke*; Osafune, Kazunori*; Nishikawa, Masahiro*
The Hellenic Society of N, 0 Pages, 2003/11
This paper describes a new structure of horizontally polarized shear(SH) wave electromagnetic acoustic transducer(EMAT). The EMAT with a Halbach magnet structure shows a stronger magnetic flux density as well as ultrasonic sound pressure than that of an EMAT with a general periodic permanent magnet(PPM) structure. The measured magnetic flux density and the ultrasound directivity distributions for both the Halbach and the PPM structure EMATs are in excellent agreement with those expected form a simulation calculation. The above EMATs were also used for inspection tests of many artificial slits; and it is found that the Halbach one performs a better detectability than the PPM one.
-chain compound [Ni(chxn)
Br]Br; Spin-charge separation in hybridized 
-
chainsFujimori, Shinichi; Ino, Akihiro; Okane, Tetsuo; Fujimori, Atsushi; Okada, Kozo*; Manabe, Toshio*; Yamashita, Masahiro*; Kishida, Hideo*; Okamoto, Hiroshi*
Physical Review Letters, 88(24), p.247601_1 - 247601_4, 2002/06
Times Cited Count：13 Percentile：60.16(Physics, Multidisciplinary)We report on the results of angle-resolved photoemission experiments on a quasi-one-dimensional -chain compound [Ni(chxn)Br]Br (chxn = 1
,2-cyclohexanediamine), a one-dimensional Heisenberg system with 
and 
K, which shows a gigantic non-linear optical effect. A "band" having about 500meV energy dispersion is found in the first half of the Brillouin zone 
, but disappears at 
. Two dispersive features, expected from the spin-charge separation, as have been observed in other quasi-one-dimensional systems like SrCuO
, are not detected. These characteristic features are well reproduced by the - chain model calculations with a small charge-transfer energy 
compared with that of one-dimensional Cu-O based compounds. We propose that this smaller is the origin of the absence of clear spin- and charge-seperation in the photoemission spectra and strong non-linear optical effect in [Ni(chxn)Br]Br.
Br]BrFujimori, Shinichi; Ino, Akihiro; Okane, Tetsuo; Fujimori, Atsushi; Okada, Kozo*; Manabe, Toshio*; Yamashita, Masahiro*; Kishida, Hideo*; Okamoto, Hiroshi*
Surface Review and Letters, 9(2), p.1065 - 1069, 2002/04
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)no abstracts in English
Metoki, Naoto; Koike, Yoshihiro; Matsuoka, Yuki; Kobayashi, Tatsuo*; Yamashita, Masahiro*
Journal of Magnetism and Magnetic Materials, 226-230(Part.1), p.414 - 416, 2001/05
no abstracts in English
Koike, Yoshihiro; Metoki, Naoto; Morii, Yukio; Kobayashi, Tatsuo*; Ishii, Tomohiko*; Yamashita, Masahiro*
Journal of the Physical Society of Japan, 69(12), p.4034 - 4042, 2000/12
Times Cited Count：6 Percentile：46.29(Physics, Multidisciplinary)no abstracts in English
Tanaka, Atsushi; Shimizu, Takashi*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Yamashita, Takao*; Watanabe, Hiroshi
JAERI-Conf 97-003, p.323 - 326, 1997/03
no abstracts in English
Ohara, Yoshihiro; Tanaka, Shigeru; Akiba, Masato; Araki, Masanori; Fujisawa, Noboru; Hanada, Masaya; Inoue, Takashi; ; Mizuno, Makoto; Okumura, Yoshikazu; et al.
JAERI-M 91-052, 176 Pages, 1991/03
no abstracts in English
Inoue, Takashi; Akiba, Masato; Araki, Masanori; Hanada, Masaya; ; Mizuno, Makoto; Okumura, Yoshikazu; Ohara, Yoshihiro; Seki, Masahiro; Tanaka, Shigeru; et al.
Fusion Engineering and Design, 18, p.369 - 376, 1991/00
Times Cited Count：3 Percentile：40.54(Nuclear Science & Technology)no abstracts in English
Yokomizo, Hideaki; Takeuchi, Hiroshi; Sugie, Tatsuo; Ogiwara, Norio; Sato, Masayasu; Nagashima, Akira; ; Nakamura, Yukiharu; Nishitani, Takeo; Neyatani, Yuzuru; et al.
Fusion Engineering and Design, 5, p.117 - 138, 1987/00
Times Cited Count：16 Percentile：80.77(Nuclear Science & Technology)no abstracts in English
Sumita, Junya; Shibata, Taiju; Mihashi, Masahiko*; Muto, Takenori*; Sato, Masahiro*; Yamashita, Ryo*; Sakaba, Nariaki
no journal, ,
The characteristics of graphite have been characterized as a function of porosity. In order to further reduce the characteristic variation and to characterize them with high accuracy, it is necessary to characterize them as a function of some detailed factors. Therefore, we focused on the open and closed pore of graphite and analyzed them based on two and three dimensional images to develop the prediction method for thermal conductivity of graphite. In the present study, it was reported analytical results of pore distribution and comparison result of predicted thermal conductivity to the experimental one.
Mihashi, Masahiko*; Muto, Takenori*; Sato, Masahiro*; Sumita, Junya; Shibata, Taiju; Sakaba, Nariaki; Yamashita, Ryo*
no journal, ,
The large size isotropic graphite is required to have small characteristic variation. Since characteristics of graphite are affected by porosity, in the first stage of improvement of large size graphite, porosity of large size isotropic graphite has been examined using mercury porosimeter.
