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Journal Articles

Validity of the source term for the Fukushima Dai-ichi Nuclear Power Station accident estimated using local-scale atmospheric dispersion simulations to reproduce the large-scale atmospheric dispersion of $$^{137}$$Cs

Kadowaki, Masanao; Furuno, Akiko; Nagai, Haruyasu; Kawamura, Hideyuki; Terada, Hiroaki; Tsuzuki, Katsunori; El-Asaad, H.

Journal of Environmental Radioactivity, 237, p.106704_1 - 106704_18, 2021/10

 Times Cited Count:0 Percentile:0(Environmental Sciences)

The source term of $$^{137}$$Cs for the Fukushima Daiichi Nuclear Power Station (FDNPS) accident was estimated from the results of local-scale atmospheric dispersion simulations and measurements. To confirm the source term's validity for reproducing the large-scale atmospheric dispersion of $$^{137}$$Cs, this study conducted hemispheric-scale atmospheric and oceanic dispersion simulations. In the dispersion simulations, the atmospheric-dispersion database system Worldwide version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI)-DB and oceanic dispersion model SEA-GEARN-FDM were used. Compared with the air concentrations of $$^{137}$$Cs measured by the Comprehensive Nuclear-Test-Ban Treaty Organization, overall, the WSPEEDI-DB simulation reproduced the measurements with some overestimation. Furthermore, the deposition amounts of $$^{137}$$Cs was investigated using concentrations of $$^{137}$$Cs in seawater. The simulated seawater concentrations of $$^{137}$$Cs were underestimated regionally in the North Pacific. The overestimation and underestimation could be improved without contradiction between the air and seawater concentrations of $$^{137}$$Cs using more realistic precipitation in atmospheric dispersion simulations. This shows that the source term validated in this study could reproduce the spatiotemporal distribution of $$^{137}$$Cs because of the FDNPS accident in both local and large-scale atmospheric dispersion simulations.

Journal Articles

Innovative measurement technique and evaluation method for unfilled portion in adhesive post-installed anchor

Ito, Michitane*; Mukai, Tomohisa*; Suzuki, Hiroshi; Nanbu, Yoshihito*; Suzuki, Junichi*; Matsuzawa, Koichi*; Kinugasa, Hideyuki*

Nihon Kenchiku Gakkai Gijutsu Hokokushu, 27(65), p.99 - 103, 2021/02

no abstracts in English

Journal Articles

Unusual redox behavior of ruthenocene confined in the micropores of activated carbon

Itoi, Hiroyuki*; Ninomiya, Takeru*; Hasegawa, Hideyuki*; Maki, Shintaro*; Sakakibara, Akihiro*; Suzuki, Ryutaro*; Kasai, Yuto*; Iwata, Hiroyuki*; Matsumura, Daiju; Owada, Mao*; et al.

Journal of Physical Chemistry C, 124(28), p.15205 - 15215, 2020/07

 Times Cited Count:4 Percentile:61.86(Chemistry, Physical)

Journal Articles

How different is the core of $$^{25}$$F from $$^{24}$$O$$_{g.s.}$$ ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

 Times Cited Count:9 Percentile:88.96(Physics, Multidisciplinary)

The structure of a neutron-rich $$^{25}$$F nucleus is investigated by a quasifree ($$p,2p$$) knockout reaction. The sum of spectroscopic factors of $$pi 0d_{5/2}$$ orbital is found to be 1.0 $$pm$$ 0.3. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus, and the core consists of $$sim$$35% $$^{24}$$O$$_{rm g.s.}$$, and $$sim$$65% excited $$^{24}$$O. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus. The result may infer that the addition of the $$0d_{5/2}$$ proton considerably changes the neutron structure in $$^{25}$$F from that in $$^{24}$$O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Journal Articles

Penetration of $$^{129}$$I released from Fukushima Daiichi Nuclear Power Plant accident in the western North Pacific Ocean

Suzuki, Takashi; Otosaka, Shigeyoshi; Kuwabara, Jun; Kawamura, Hideyuki; Kobayashi, Takuya

JAEA-Conf 2018-002, p.103 - 106, 2019/02

To investigate the dynamics of radionuclides in the ocean released by the accident at Fukushima Daiichi Nuclear Power Plant (1F), vertical distributions of $$^{129}$$ I at three stations in the western North Pacific was revealed. The 1F accident-derived $$^{129}$$ I existed within the mixed layer at 3 stations. The maximum layer of the 1F accident-derived $$^{129}$$ I existed at the depth of 370 m - 470 m at the most southern station. Considering the dissolved oxygen concentration and the current velocity arround the station, the maximum layer of the 1F accident-derived $$^{129}$$ I would be fromed that $$^{129}$$I which existed in the surface seawater at other area of observation point was carried to the depth of 370 m - 470 m by the fast downward flow.

Journal Articles

Vertical distribution of $$^{129}$$I released from the Fukushima Daiichi Nuclear Power Plant in the Kuroshio and Oyashio current areas

Suzuki, Takashi; Otosaka, Shigeyoshi; Kuwabara, Jun; Kawamura, Hideyuki; Kobayashi, Takuya

Marine Chemistry, 204, p.163 - 171, 2018/08

 Times Cited Count:1 Percentile:9.75(Chemistry, Multidisciplinary)

To investigate the penetration of radionuclides released from Fukushima Daiichi Nuclear Power Plant (FDNPP), depth profiles were revealed at Kuroshio current, transition, and Oyashio current areas. The FDNPP-derived $$^{129}$$I was found in surface layer at Oyashio current and transition areas and in sub-surface layer at Kuroshio current area. Moreover, it was found that the FDNPP-derived $$^{129}$$I/$$^{134}$$Cs ratios in the Oyashio current and transition areas were higher than that in the FDNPP reactor. The higher FDNPP-derived $$^{129}$$I/$$^{134}$$Cs ratios suggest three potential mechanisms for the migration of radionuclides in the environment: (1) radioiodine was released more easily than radiocesium by the FDNPP accident, (2) $$^{129}$$I was supplied from the atmosphere by re-emitted $$^{129}$$I from contaminated areas around Fukushima, (3) leaked water that removed radiocesium reached the sampling stations. The FDNPP-derived $$^{129}$$I in sub-surface layer would be transported by the meander of the Kuroshio Extension current.

Journal Articles

Rapid separation of zirconium using microvolume anion-exchange cartridge for $$^{93}$$Zr determination with isotope dilution ICP-MS

Asai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*

Talanta, 185, p.98 - 105, 2018/08

 Times Cited Count:7 Percentile:45.32(Chemistry, Analytical)

Estimating the risks associated with radiation from long-lived fission products (LLFP) in radioactive waste is essential to ensure the long-term safety of potential disposal sites. In this study, the amount of $$^{93}$$Zr, a LLFP, was determined by ICP-MS after separating Zr from a spent nuclear fuel solution using a microvolume anion-exchange cartridge (TEDA cartridge). The TEDA cartridge achieved highly selective separation of Zr regardless of its small bed volume of 0.08 cm$$^{3}$$. The time taken to complete the Zr separation was 1.2 min with a flow rate of 1.5 mL/min, which was 10 times faster than that for a conventional anion-exchange resin column. Almost all the other elements were removed, leading to accurate measurement of $$^{93}$$Zr. The result connects experimental value to theoretical prediction provided by ORIGEN2, which requires verification. With the measured value, we demonstrated that the theoretical value is reliable enough to estimate radiation risks.

Journal Articles

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

Ikeda, Yoshimasa*; Taketani, Atsushi*; Takamura, Masato*; Sunaga, Hideyuki*; Kumagai, Masayoshi*; Oba, Yojiro*; Otake, Yoshie*; Suzuki, Hiroshi

Nuclear Instruments and Methods in Physics Research A, 833, p.61 - 67, 2016/10

 Times Cited Count:29 Percentile:97.29(Instruments & Instrumentation)

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by the large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 minutes. The minimum resolution of the 110 reflection for RANS is approximately 2.5 % at 8 $$mu$$s of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 $$mu$$s, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenite phase was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS was proved to be capable for neutron engineering diffraction aiming for the easy access measurement of the texture and the amount of retained austenite.

Journal Articles

Texture evaluation in ductile fracture process by neutron diffraction measurement

Sunaga, Hideyuki*; Takamura, Masato*; Ikeda, Yoshimasa*; Otake, Yoshie*; Hama, Takayuki*; Kumagai, Masayoshi*; Suzuki, Hiroshi; Suzuki, Shinsuke*

Journal of Physics; Conference Series, 734(Part B), p.032027_1 - 032027_4, 2016/09

 Times Cited Count:0 Percentile:0.03

A neutron diffraction measurement was performed to reveal microstructural aspects of the ductile fracture in ferritic steel. The diffraction patterns were continuously measured at the center of the reduced area while a tensile specimen was loaded under tension until the end of the fracture process. The measurement results showed that the volume fraction of (110)-oriented grains increased when the texture evolved as a result of plastic deformation. But the mechanism of texture evolution may be changed during necking, decreasing an increase rate of the volume fraction.

Journal Articles

Non-destructive texture measurement of steel sheets with compact neutron source "RANS"

Takamura, Masato*; Ikeda, Yoshimasa*; Sunaga, Hideyuki*; Taketani, Atsushi*; Otake, Yoshie*; Suzuki, Hiroshi; Kumagai, Masayoshi*; Hama, Takayuki*; Oba, Yojiro*

Journal of Physics; Conference Series, 734(Part B), p.032047_1 - 032047_4, 2016/08

 Times Cited Count:4 Percentile:87.32

Neutron diffraction is well known to be a useful technique for measuring a bulk texture of metallic materials taking advantage of a large penetration depth of the neutron beam. However, this technique has not been widely utilized for the texture measurement because large facilities like a reactor or a large accelerator are required in general. In contrast, RANS (Riken Accelerator-driven Compact Neutron Source) has been developed as a neutron source which can be used easily in laboratories. In this study, texture evolution in steel sheets with plastic deformation was successfully measured using RANS. The results show the capability of the compact neutron source for the analysis of the crystal structure of metallic materials, which leads us to a better understanding of plastic deformation behavior.

JAEA Reports

Decommissioning activities and R&D of nuclear facilities in the second midterm plan

Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.

JAEA-Review 2016-008, 98 Pages, 2016/07


Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.

Journal Articles

Preparation of microvolume anion-exchange cartridge for inductively coupled plasma mass spectrometry-based determination of $$^{237}$$Np content in spent nuclear fuel

Asai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*

Analytical Chemistry, 88(6), p.3149 - 3155, 2016/03

 Times Cited Count:7 Percentile:34.85(Chemistry, Analytical)

Neptunium-237 ($$^{237}$$Np) is one of the major long-lived radionuclides found in spent nuclear fuel. To evaluate the long-term safety of a HLW repository, the $$^{237}$$Np content in spent nuclear fuel must be determined. In this study, micro-volume anion-exchange porous polymer disk-packed cartridges were prepared for Am-Np separation, which is required prior to the measurement of $$^{237}$$ Np with ICP-MS. Disks with a volume of 0.08 cm$$^{3}$$ were cut out from porous sheets having triethylenediamine (TEDA)-containing polymer chains densely attached on the pore surface. The resulting TEDA-introduced disk cartridge was applied to a spent nuclear fuel sample. The chemical yield of Np was 90.4%, which is sufficiently high for ICP-MS measurement of $$^{237}$$Np. Compared with the conventional separation technique using commercially available anion-exchange resin columns, the time required to adsorb, wash and elute Np using the TEDA-introduced disk cartridge was reduced by 75%.

Journal Articles

High power laser developments with femtosecond to nanosecond pulse durations for laser shock science and engineering

Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.

Reza Kenkyu, 42(6), p.441 - 447, 2014/06

We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.

Journal Articles

Biological significance of fluorine-18-$$alpha$$-methyltyrosine (FAMT) uptake on PET in patients with oesophageal cancer

Suzuki, Shigemasa*; Kaira, Kyoichi*; Ohshima, Yasuhiro; Ishioka, Noriko; Soda, Makoto*; Yokobori, Takehiko*; Miyazaki, Tatsuya*; Oriuchi, Noboru*; Tominaga, Hideyuki*; Kanai, Yoshikatsu*; et al.

British Journal of Cancer, 110(8), p.1985 - 1991, 2014/04

 Times Cited Count:20 Percentile:61.85(Oncology)

Journal Articles

High-resolution crystal structure of copper amine oxidase from ${it Arthrobacter globiformis}$; Assignment of bound diatomic molecules as O$$_{2}$$

Murakawa, Takeshi*; Hayashi, Hideyuki*; Sunami, Tomoko; Kurihara, Kazuo; Tamada, Taro; Kuroki, Ryota; Suzuki, Mamoru*; Tanizawa, Katsuyuki*; Okajima, Toshihide*

Acta Crystallographica Section D, 69(12), p.2483 - 2494, 2013/12

 Times Cited Count:9 Percentile:60.68(Biochemical Research Methods)

The crystal structure of a Cu amine oxidase from ${it Arthrobacter globiformis}$ was determined at 1.08 ${AA}$ resolution with the use of low-molecular-weight polyethylene glycol (LMW PEG; average molecular weight $$sim$$200) as a cryoprotectant. The final crystallographic $$R$$-factor and $$R$$$$_{rm free}$$ value are 13.0% and 15.0%, respectively. Several molecules of LMW PEG were found to occupy cavities in the protein interior including the active site, which resulted in the marked reduction of the overall ${it B}$ factor and consequently led to a sub-atomic resolution structure for a relatively large protein with a monomer molecular weight of $$sim$$70,000. About 40% of all the presumed hydrogen atoms were observed as clear electron densities in the $$F$$$$_{rm o}$$ - $$F$$$$_{rm c}$$ difference map. Multiple minor conformers were also identified for many residues. Anisotropic displacement fluctuations were evaluated in the active site that contains a post-translationally derived quinone cofactor and a Cu atom. Furthermore, diatomic molecules, most likely molecular oxygen, are bound to the protein, one of which is located in the region that has been previously proposed as an entry route for the substrate dioxygen from the central cavity of the dimer interface to the active site.

Journal Articles

Iodine-129 concentration in seawater near Fukushima before and after the accident at the Fukushima Daiichi Nuclear Power Plant

Suzuki, Takashi; Otosaka, Shigeyoshi; Kuwabara, Jun; Kawamura, Hideyuki; Kobayashi, Takuya

Biogeosciences, 10(6), p.3839 - 3847, 2013/06

 Times Cited Count:20 Percentile:60.11(Ecology)

no abstracts in English

Journal Articles

Ultra-intense, high spatio-temporal quality petawatt-class laser system and applications

Kiriyama, Hiromitsu; Shimomura, Takuya; Mori, Michiaki; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Esirkepov, T. Z.; Hayashi, Yukio; et al.

Applied Sciences (Internet), 3(1), p.214 - 250, 2013/03

 Times Cited Count:13 Percentile:53.78(Chemistry, Multidisciplinary)

This paper reviews techniques for improving the temporal contrast and spatial beam quality in an ultra-intense laser system that is based on chirped-pulse amplification (CPA). We describe the design, performance, and characterization of our laser system, which has the potential for achieving a peak power of 600 TW. We also describe applications of the laser system in the relativistically dominant regime of laser-matter interactions and discuss a compact, high efficiency diode-pumped laser system.

Journal Articles

ITER project; Status of procurement activities in domestic agency of Japan and application of HIP technology

Takatsu, Hideyuki; Enoeda, Mikio; Suzuki, Satoshi; Hirose, Takanori; Koizumi, Norikiyo; Takahashi, Koji

Proceedings of International Conference on Hot Isostatic Pressing (HIP '11), p.35 - 40, 2011/04

ITER is a mega-science fusion project, under an international collaboration of seven Members, to construct, operate, exploit and decommission a tokamak-type experimental reactor at Cadarache site with a mission to demonstrate the scientific and technological feasibility. The ITER Project started technical activities in 2007 and is now in a serious construction phase. Domestic Agencies of the seven member countries are in the process of manufacturing long lead-time components. Some of the ITER components apply HIP technology in manufacturing processes in view of a number of potential advantages. In this paper, examples and status of application of HIP technology by the Domestic Agency of Japan are overviewed.

Journal Articles

Geostatistical modeling of groundwater properties and assessment of their uncertainties

Yamamoto, Shinya*; Honda, Makoto*; Sakurai, Hideyuki*; Suzuki, Makoto*; Sanada, Hiroyuki; Sugita, Yutaka; Matsui, Hiroya

Proceedings of 14th Annual Conference of the International Association for Mathematical Geosciences (IAMG 2010) (CD-ROM), 12 Pages, 2010/09

The distribution of groundwater properties is important for understanding of the deep underground hydrogeological environments in the design of the HLW disposal facilities. This study proposes a geostatistical system for modeling the chemical properties of groundwater which have a correlation with the resistivity data obtained from widespread and exhaustive survey. The proposed system is consists of two methodologies (resistivity data integration using Simple Kriging with varying local mean (SKlm) and 3D distribution modeling of hydro-chemical properties of groundwater estimated by SKlm algorithm). 2 types of uncertainty are considered: (1) Aleatory uncertainty; (2) Epistemic uncertainty. As a result, the uncertainties of the proposal model have been estimated lower than other traditional model's.

Journal Articles

Geostatistical modeling of groundwater properties and assessment of thier uncertainties

Honda, Makoto*; Yamamoto, Shinya*; Sakurai, Hideyuki*; Suzuki, Makoto*; Sanada, Hiroyuki; Sugita, Yutaka; Matsui, Hiroya

Doboku Gakkai Rombunshu, C, 66(3), p.609 - 624, 2010/08

This paper proposes a geostatistical system for modeling the groundwater properties which have a correlation with the ground resistivity data obtained from widespread and exhaustive electromagnetic survey. That is, the methodology for the integration of resistivity data measured by various methods and the methodology for modeling the groundwater properties using the integrated resistivity data has been developed. The proposed system has also been validated using the data obtained in the surface-based investigations of the Horonobe URL project. Additionally, the quantification of uncertainties in the estimated model has been tried by numerical simulations based on the data. As a result, the uncertainties of the proposal model have been estimated lower than other traditional model's.

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