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Journal Articles

Development of evaluation method for variability of groundwater flow conditions associated with long-term topographic change and climate perturbations

Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06

In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.

Journal Articles

Preliminary results for natural groundwater colloids in sedimentary rocks of the Horonobe Underground Research Laboratory, Hokkaido, Japan

Sasamoto, Hiroshi; Onda, Shingo*

Geological Society Special Publications, 482, 13 Pages, 2018/09

 Times Cited Count:1 Percentile:24.18

Colloid concentration is an important parameter in models of colloid-facilitated transport. The purpose of present study is to characterize colloid concentrations and colloid stability in natural groundwater from the Horonobe Underground Research Laboratory (URL) as for development of a procedure. The particle sizes of colloids in groundwaters from the Horonobe URL range from several nm to ca. 500 nm, with a mode particle size of ca. 120 nm. Evaluation of colloid stability by DLVO theory suggests that larger colloids (i.e., $$>$$100 nm in diameter) would be more stable than smaller colloids in some groundwaters. The estimated colloid particle concentrations ranged from 2.33$$times$$10$$^{6}$$ to 1.12$$times$$10$$^{8}$$ pt/mL, and mass concentrations were estimated to range from 45 to 1540 $$mu$$g/L for diameters greater than 100 nm. Colloids in Horonobe groundwaters appear to be less stable, with a moderate potential for transport, than colloids investigated in similar international studies. This reduced stability may be due to relatively higher ionic strengths and moderate dissolved organic concentrations in Horonobe groundwaters compared to their international counterparts.

Journal Articles

Observation of simultaneous oscillations of bunch shape and position caused by odd-harmonic beam loading in the Japan Proton Accelerator Research Complex Rapid Cycling Synchrotron

Yamamoto, Masanobu; Nomura, Masahiro; Shimada, Taihei; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Sugiyama, Yasuyuki*; Yoshii, Masahito*

Progress of Theoretical and Experimental Physics (Internet), 2017(11), p.113G01_1 - 113G01_24, 2017/11

 Times Cited Count:1 Percentile:15.98(Physics, Multidisciplinary)

Two proton bunches circulates the accelerator ring in the J-PARC 3GeV synchrotoron (RCS). The accelerating voltage is also generated in twice of the revolution frequency. The major Fourier component of the wake voltage should become even harmonics. However, the odd harmonics grow and cause a large number of beam loss. The beam measurement suggests that the odd harmonic wake voltages promote oscillations of not only the bunch position but also the bunch shape. The oscillations continue because they amplify the odd harmonic beam components. A particle tracking simulation can reproduce these simultaneous oscillations. It is found that the odd harmonic wake voltages lead to severe rf bucket distortion that results in beam loss. As a result, introducing a beam loading compensation system for the minor harmonics can prevent the beam loss and it would contribute the stable accelerator operation with the reduction of the activation.

JAEA Reports

Synthesized research report in the second mid-term research phase, Mizunami Underground Research Laboratory Project, Horonobe Underground Research Laboratory Project and Geo-stability Project (Translated document)

Hama, Katsuhiro; Sasao, Eiji; Iwatsuki, Teruki; Onoe, Hironori; Sato, Toshinori; Fujita, Tomo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Takeda, Masaki; Aoyagi, Kazuhei; et al.

JAEA-Review 2016-014, 274 Pages, 2016/08


We synthesized the research results from the Mizunami/Horonobe Underground Research Laboratories (URLs) and geo-stability projects in the second midterm research phase. This report can be used as a technical basis for the Nuclear Waste Management Organization of Japan/Regulator at each decision point from siting to beginning of disposal (Principal Investigation to Detailed Investigation Phase).

JAEA Reports

Study on stability criterion of xenon oscillation based on analysis solution for HTGR design

Fukaya, Yuji; Tokuhara, Kazumi; Nishihara, Tetsuo

JAEA-Research 2016-008, 52 Pages, 2016/06


To investigate the xenon stability quantitatively, a study on stability criterion of xenon oscillation based on an analysis solution for HTGR design had been performed. Randall developed the stability criterion method of xenon oscillation based on an analysis solution. And, that have been employed for a LWR design. On the other hand, HTGR is also planted to design new type of reactors, such as Pu fueled reactor, and it is necessary to confirm the xenon stability of those new types of reactors. Then, we developed the criterion method based on the Randall's method termed D-XESC/A, and high xenon stability of HTGR and feasibility for Pu fueled reactor is confirmed by comparing with xenon stability of other types of reactors.

Journal Articles

Thermal stability of a magnetic domain wall in nanowires

Fukami, Shunsuke*; Ieda, Junichi; Ono, Hideo*

Physical Review B, 91(23), p.235401_1 - 235401_7, 2015/06

 Times Cited Count:14 Percentile:60.25(Materials Science, Multidisciplinary)

We study thermal stability of a magnetic domain wall pinned in nanowires made of Co/Ni multilayers, and analyze the effective volume that governs the thermal stability. We find that, above a critical wire width, the domain wall depinning is initiated by a subvolume excitation and that the critical width is dependent on the wire thickness. The obtained findings are supported by the distribution of critical current density for domain wall depinning and are qualitatively described by considering the balance between the Zeeman energy and domain wall elastic energy.

Journal Articles

Induction of genetic instability by transfer of a UV-A-irradiated chromosome

Urushibara, Ayumi*; Kodama, Seiji*; Yokoya, Akinari

Mutation Research; Genetic Toxicology And Environmental Mutagenesis, 766, p.29 - 34, 2014/05

 Times Cited Count:9 Percentile:38.15(Biotechnology & Applied Microbiology)

Journal Articles

Investigation of a model to evaluate the pyrolysis properties of zinc stearate

Abe, Hitoshi; Tashiro, Shinsuke; Miyoshi, Yoshinori

Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(1), p.10 - 21, 2007/03

In MOX fuel fabrication facility, zinc stearate will be added into the MOX powder as addition material. If the material is added in large excess by miss operation, criticality characteristics of the MOX fuel would be influenced because it has neutron moderation effect. If criticality condition should be induced by the excess addition, physical variations, such as melting and pyrolysis of the material, must be caused by the fission energy and dynamic characteristics of the MOX fuel must be affected. To contribute quantitative evaluation of the dynamic characteristics, thermal properties data such as exo/endothermic calorific values, reaction rates, etc. with the respective physical variations and release behavior of pyrolysis gas were measured. It was found the exo/endothermic behavior with rinsing temperature of the material could be divided into six regions and rapid pressure rise caused by the pyrolysis reaction over about 400 $$^{circ}$$C. Furthermore, on the basis of the results, evaluation model for the thermal properties under the criticality condition was also investigated.

Journal Articles

Suppression of neoclassical tearing modes towards stationary high-beta plasmas in JT-60U

Isayama, Akihiko; JT-60 Team

Plasma Science and Technology, 8(1), p.36 - 40, 2006/01

 Times Cited Count:3 Percentile:11.82(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Measurement of toroidal structure of electron temperature with electron cyclotron emission diagnostic in JT-60U

Isayama, Akihiko; Oyama, Naoyuki; Urano, Hajime; JT-60 Team

Proceedings of 21st IEEE/NPSS Symposium on Fusion Engineering (SOFE 2005) (CD-ROM), 4 Pages, 2006/00

no abstracts in English

Journal Articles

MHD instabilities leading to disruptions in low beta JT-60U reversed shear plasmas

Takechi, Manabu; Fujita, Takaaki; Ishii, Yasutomo; Ozeki, Takahisa; Suzuki, Takahiro; Isayama, Akihiko; JT-60 Team

Nuclear Fusion, 45(12), p.1694 - 1699, 2005/12

 Times Cited Count:7 Percentile:26.39(Physics, Fluids & Plasmas)

High performance reversed shear discharges with strong internal transport barrier (ITB) and flat pressure profile in the plasma core region disrupt frequently even with low beta. We analyzed MHD instabilities leading to low beta disruption with measuring fluctuations and current profile with MSE measurement. We mainly observed two type of disruptions. One is the disruption without precursor at $$qeff~integer$$. The other is the disruption with n=1 precursor of $$gamma$$$$>$$100 ms. To explain these characteristics of disruption, we introduce the simple model such as, disruption occurs when the both MHD instabilities at plasma surface and at safety factor being equal to surface mode are unstable. This simple model can explain almost all observed disruption by two process. One is the surface mode triggered disruption, which occurs when qeff change, corresponding q surface at ITB layer changes discretely. The other is the internal mode triggered disruption, which occurs when corresponding q surface become unstable gradually.

Journal Articles

Conversion of endohedral $$^{133}$$Xe-fullerene to endohedral $$^{133}$$Xe-fullerenol to be used in nuclear medicine

Watanabe, Satoshi; Ishioka, Noriko; Sekine, Tsutomu*; Kudo, Hiroshi*; Shimomura, Haruhiko*; Muramatsu, Hisakazu*; Kume, Tamikazu

Journal of Radioanalytical and Nuclear Chemistry, 266(3), p.499 - 502, 2005/11

 Times Cited Count:9 Percentile:55.69(Chemistry, Analytical)

no abstracts in English

Journal Articles

How far does the area of superheavy elements extend?; Decay modes of heavy and superheavy nuclei predicted by a mass formula

Koura, Hiroyuki; Tachibana, Takahiro*

Nihon Butsuri Gakkai-Shi, 60(9), p.717 - 724, 2005/09

no abstracts in English

Journal Articles

Tritium accounting stability of a ZrCo bed with "In-bed" gas flowing calorimetry

Hayashi, Takumi; Suzuki, Takumi; Yamada, Masayuki; Nishi, Masataka

Fusion Science and Technology, 48(1), p.317 - 323, 2005/07

 Times Cited Count:10 Percentile:59.2(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Magnetic field stabilization at the JAERI AVF cyclotron

Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Nakamura, Yoshiteru; et al.

Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.745 - 747, 2005/07

no abstracts in English

Journal Articles

Development of an innovative integrator being resistant to an excessive high voltage input at plasma instabilities

Kawamata, Yoichi; Yonekawa, Izuru; Kurihara, Kenichi

Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03

no abstracts in English

Journal Articles

Introduction of plasma characteristics for fusion reactor design

Kamada, Yutaka

Nihon Genshiryoku Gakkai-Shi, 47(1), p.45 - 52, 2005/01

no abstracts in English

Journal Articles

Nonlocal energetic particle mode in a JT-60U plasma

Todo, Yasushi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao

Physics of Plasmas, 12(1), p.012503_1 - 012503_7, 2005/01

 Times Cited Count:45 Percentile:81.96(Physics, Fluids & Plasmas)

Energetic-ion driven instability in a JT-60U plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat and the spatial profile consists of a single primary harmonic m/n = 2/1. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic ion orbit width and energetic ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles.

Journal Articles

Super heavy elements

Koura, Hiroyuki

Uchu, 21(10), p.4 - 9, 2005/01

no abstracts in English

Journal Articles

Escaping fast ion diagnostics for the fast particle transport analysis

Isobe, Mitsutaka*; Shinohara, Koji

Purazuma, Kaku Yugo Gakkai-Shi, 80(12), p.1036 - 1043, 2004/12

Escaping energetic ion diagnostics in magnetically confined plasma experiments are described in this lecture note. Experimental results from escaping energetic ion diagnostics in TFTR, JFT-2M, CHS and W7-AS are shown. In addition to mechanism of energetic ion loss from a viewpoint of particle orbit, effect of MHD activity on energetic particle transport is reviewed.

300 (Records 1-20 displayed on this page)