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Sano, Naruto; Yamashita, Naoki; Watanabe, Masaya; Tsukada, Manabu*; Hoshino, Kazutoyo*; Hirai, Koki; Ikegami, Yuta*; Tashiro, Shinsuke; Yoshida, Ryoichiro; Hatakeyama, Yuichi; et al.
JAEA-Technology 2023-029, 36 Pages, 2024/03
JAEA-Technology-2023-029.pdf:2.47MB
At the Waste Safety Testing Facility (WASTEF), the gamma ray irradiation device "Gamma Cell 220" was relocated from the 4th research building of the Nuclear Science Research Institute in FY2019, and the use of gamma ray irradiation has begun. Initially, Fuel Cycle Safety Research Group, Fuel Cycle Safety Research Division, Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness, the owner of this device, conducted the tests as the main user, but since 2022, other users, including those outside the organization, have started using it. The gamma ray irradiation device "Gamma Cell 220" is manufactured by Nordion International Inc. in Canada. Since it was purchased in 1989, the built-in 60Co radiation source has been updated once, and safety research related to nuclear fuel cycles, etc. It is still used for this purpose to this day. This report summarizes the equipment overview of the gamma ray irradiation device "Gamma Cell 220", its permits and licenses at WASTEF, usage status, maintenance and inspection, and future prospects.
Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Koike, Yuko; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; Nagai, Shinji; et al.
JAEA-Review 2023-046, 164 Pages, 2024/03
JAEA-Review-2023-046.pdf:4.2MB
The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2022 to March 2023 and the results of dose calculations for the surrounding public due to the release of radioactive materials into the atmosphere and ocean. In the results of the above environmental radiation monitoring, many items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016), which occurred in March 2011. Also included as appendices are an overview of the environmental monitoring plan, an overview of measurement methods, measurement results and their changes over time, meteorological statistics results, radioactive waste release status, and an evaluation of the data which deviated of the normal range.
Nakada, Akira; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Futagawa, Kazuo; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; et al.
JAEA-Review 2022-078, 164 Pages, 2023/03
JAEA-Review-2022-078.pdf:2.64MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2021 to March 2022. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.
KEK Proceedings 2022-2, p.61 - 66, 2022/11
The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09
Times Cited Count：3 Percentile：45.99(Nuclear Science & Technology)A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 
s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion (CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after CF reaction.
Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08
Times Cited Count：3 Percentile：45.99(Nuclear Science & Technology)A muon () having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by and form a muonic hydrogen molecular ion, dt. Due to the short inter-nuclear distance of dt, the nuclear fusion, d +t
+ n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion (CF). Recently, the interest on CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of CF in a two-layered hydrogen isotope target.
without stacking disorder by evacuating hydrogen from hydrogen hydrateKomatsu, Kazuki*; Machida, Shinichi*; Noritake, Fumiya*; Hattori, Takanori; Sano, Asami; Yamane, Ryo*; Yamashita, Keishiro*; Kagi, Hiroyuki*
Nature Communications (Internet), 11, p.464_1 - 464_5, 2020/02
Times Cited Count：45 Percentile：87.08(Multidisciplinary Sciences)Water freezes below 0
C at ambient pressure ordinarily to ice I
, with hexagonal stacking sequence. Under certain conditions, ice with a cubic stacking sequence can also be formed, but ideal ice I without stacking-disorder has never been formed until recently. Here we demonstrate a route to obtain ice I without stacking-disorder by degassing hydrogen from the high-pressure form of hydrogen hydrate, C
, which has a host framework isostructural with ice I. The stacking-disorder free ice I is formed from C via an intermediate amorphous or nano-crystalline form under decompression, unlike the direct transformations occurring in ice XVI from neon hydrate, or ice XVII from hydrogen hydrate. The obtained ice I shows remarkable thermal stability, until the phase transition to ice I at 250 K, originating from the lack of dislocations. This discovery of ideal ice I will promote understanding of the role of stacking-disorder on the physical properties of ice as a counter end-member of ice I.
Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Furumoto, Kenichiro*; Sato, Hisaki*; Ishibashi, Ryo*; Yamashita, Shinichiro
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.670 - 674, 2019/09
Ishibashi, Ryo*; Tanabe, Shigetada*; Kondo, Takao*; Yamashita, Shinichiro; Nagase, Fumihisa
Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09
For improving the corrosion resistance of silicon carbide (SiC) in boiling-water-reactor environments, corrosion-resistant coatings on SiC were evaluated. Due to its hydrogen-generation rate and reaction heat being lower than those of conventional Zircaloy, SiC is expected to be an appropriate material for accident-tolerant fuels. However, there are still many critical issues with the practical application of SiC fuel cladding and fuel channel boxes, one of which is hydrothermal corrosion. Silicon carbide is chemically stable, but silicon oxide formed by oxidation of SiC dissolves in high temperature water. Although the rate of SiC dissolution is very small, the dissolution must be suppressed to comply with regulations for dissolved silica concentration in reactor coolant. In this study, the corrosion behavior of candidate coatings for SiC substrates were evaluated before and after exposure to unirradiated high-purity-water environments.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Tanno, Takeo*; Sanada, Hiroyuki; Sato, Toshinori
JAEA-Research 2013-040, 51 Pages, 2014/03
JAEA-Research-2013-040.pdf:6.86MB
For the research and development about high-level radioactive waste disposal, it is important to evaluate the mechanical stability of the excavation and the long-term behavior of in situ rock. However, from the limited information such as the bowling core before the excavation, it is difficult to evaluate the mechanical properties of in situ rock containing cracks. For this reason, evaluation of rock properties based on Specific Energy using mechanical data from an excavation machine is carried out. This report describes the results of the joint research carried out in FY 2010 to FY 2012.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.247 - 248, 2013/08
no abstracts in English
Hirayama, Ryoichi*; Uzawa, Akiko*; Takase, Nobuhiro*; Matsumoto, Yoshitaka*; Noguchi, Miho; Koda, Kana*; Ozaki, Masakuni*; Yamashita, Kei*; Li, H.*; Kase, Yuki*; et al.
Mutation Research; Genetic Toxicology And Environmental Mutagenesis, 756(1-2), p.146 - 151, 2013/08
Times Cited Count：24 Percentile：62.77(Biotechnology & Applied Microbiology)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.
Niizato, Tadafumi; Imai, Hisashi*; Maekawa, Keisuke; Yasue, Kenichi; Kurikami, Hiroshi; Shiozaki, Isao*; Yamashita, Ryo*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 10 Pages, 2011/10
A critical issue for building confidence in the long-term safety of geological disposal is to demonstrate the stability of the geosphere, taking into account its likely future evolution. This study aims to establish comprehensive techniques for characterising the overall evolution of coastal sites through studying the palaeohydrogeological evolution in the coastal system around the Horonobe area, Hokkaido, northern Japan. Information on natural events and processes related to the palaeohydrogelogical evolution of the area have been integrated into the conceptual models that indicates the temporal and spatial sequences of the events and processes, such as climatic and sea-level changes, palaeogeography, and geomorphological and geological evolution in the area. The groundwater flow simulation, which is based on the conceputualisation of the long-term geosphere evolution, shows the sensitivities of natural events and processes on groundwater flow properties in a coastal setting.
Hikima, Ryoichi; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*
Heisei-23 Nendo (2011 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.265 - 266, 2011/09
no abstracts in English
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：80.39(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.
Imai, Hisashi*; Yamashita, Ryo*; Shiozaki, Isao*; Urano, Kazuhiko*; Kasa, Hiroyoshi*; Maruyama, Yoshio*; Niizato, Tadafumi; Maekawa, Keisuke
JAEA-Research 2009-001, 116 Pages, 2009/03
JAEA-Research-2009-001.pdf:32.12MB
Evaluation of long-term geological evolution and its impact on groundwater flow is one of the major themes within the frame of Horonobe Underground Research Laboratory Project. For the purpose of development of a groundwater flow modeling methodology considering the effects of long-term geological evolution, following three items were studied: (1) Upgrade of SMS (Sequential Modeling System of geo-environmental evolution impact on groundwater flow) which was developed in 2006 FY; (2) Groundwater flow simulation under more realistic conditions of geological structures and hydrogeological conditions; and (3) Sensitivity study of geo-environmental evolution impacts on groundwater flow. The studies showed following suggestive results. (1) Development of a precise time step setting enabled to narrow the gaps in simulated head between time steps in which the model configuration used to deformed. (2) Several aspects have been found from studies on impact factors such as deposition on pore pressure, recharge rate and difference in density of saline groundwater. For evaluation of pore pressure induced by deposition, it is necessary to model the porosity and permeability variation considering the exceed pore pressure change. The setting of recharge rate during the Ice Age influence the characteristics of groundwater flow in coastal and hilly areas. The density of groundwater is not so influential as topological potential factors, however it is effective for the characteristics of groundwater flow in coastal area and intrusion of recharge water from ground surface. (3) The sensitivity study on faulting characteristics indicated that the two types of fault configuration and the hydraulic conductivity setting considered are not influential on the nature of groundwater flow above the depth of 500 m.
Yamazaki, Yuji*; Tamada, Taro; Kasai, Noriyuki*; Urakawa, Itaru*; Aono, Yukiko*; Hasegewa, Hisashi*; Fujita, Toshiro*; Kuroki, Ryota; Yamashita, Takeyoshi*; Fukumoto, Seiji*; et al.
Journal of Bone and Mineral Research, 23(9), p.1509 - 1518, 2008/09
Times Cited Count：150 Percentile：94.53Fibroblast growth factor (FGF)23 is proposed to play a physiological role in the regulation of phosphate and vitamin D metabolism; deranged circulatory levels of FGF23 cause several diseases with abnormal mineral metabolism. We developed two antibodies (FN1 and FC1) that recognize the N- and C-terminal regions of FGF23, respectively. Both FN1 and FC1 inhibited FGF23 activity in a cell-based Klotho-dependent reporter assay. The present study using neutralizing antibodies confirms that FGF23 is a physiological regulator of phosphate and vitamin D metabolism. Then, we addressed the mechanism of action for these neutralizing antibodies. Structural analysis of the FGF23/FN1-Fab complex revealed that FN1 masked putative FGF receptor-binding sites in the N-terminal domain of FGF23, while biochemical analyses showed that FC1 interfered with the association between FGF23 and Klotho by binding to the C-terminal domain of FGF23. Taken together, our results suggest that the N- and C-terminal domains of FGF23 are responsible for association with cognate FGF receptors and Klotho, respectively, and that these interactions are indispensable for FGF23 activity.
Kurikami, Hiroshi; Yasue, Kenichi; Niizato, Tadafumi; Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*
Chikasui Ryudo Kaiseki To Moderuka Ni Kansuru Shimpojium Happyo Rombunshu, p.59 - 66, 2007/01
no abstracts in English
Hiroki, Akihiro; Maekawa, Yasunari; Katakai, Ryoichi*; Yamashita, Takashi*; Muroya, Yusa*; Katsumura, Yosuke*; Yoshida, Masaru
Macromolecules, 39(12), p.4132 - 4137, 2006/06
Times Cited Count：5 Percentile：16.83(Polymer Science)Hydrogels, which were synthesized by radiation-induced polymerization and cross-linked reactions of acryloyl-L-proline methyl ester at 0C in aqueous alcohol solutions, exhibit ultraslow volume change in response to variations in external temperature. The shrinking speed of the hydrogels prepared in aqueous alcohol is 1000 times slower than that of the hydrogel prepared in pure water; e.g., the hydrogel prepared in aqueous 1-propanol at 0C shrank in 6 months. It is revealed that the ultraslow thermo-response consists of quick-shrinking and slow-shrinking periods; the ratio between the duration of the two periods depends on the alcohol molecules in the solution. The generation of hydroxyl group at the side chain of the polymer by the coupling reaction between -hydroxyalkyl radicals of alcohols and -radical of proline moiety was confirmed by GC/MS analysis of the radiation products. The hydrogen bonding domain containing the hydroxyl groups is proposed to be responsible for the ultraslow response.
