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Journal Articles

Overview of environmental impact assessment studies on radioactive contamination after the Fukushima Daiichi Nuclear Power Plant accident

Iijima, Kazuki; Hayashi, Seiji*; Tamaoki, Masanori*

Global Environmental Research (Internet), 24(2), p.85 - 93, 2021/06

Environmental radioactive contamination by the Fukushima Daiichi Nuclear Power Plant accident has clearly been declining during the passage of almost 10 years from the accident. However, the prolongation of radioactive contamination in natural ecosystems probably derived from forested area without decontamination is pointed out by many studies, so more detailed examination will be needed for environmental dynamics of bioavailable radiocesium and its transfer to ecosystems. Also for influence of radiation to organisms, effects of evacuation on wild organisms are more pronounced than direct effect from radiation, especially in Fukushima evacuation area.

Journal Articles

Diffusion and retention behaviour of Cs in illite-added compacted montmorillonite

Ishidera, Takamitsu; Kurosawa, Seiichi*; Hayashi, Masanori*; Uchikoshi, Keiji*; Beppu, Hikari*

Clay Minerals, 51(2), p.161 - 172, 2016/05

 Times Cited Count:4 Percentile:14.61(Chemistry, Physical)

The sorption and diffusion behavior of Cs in illite-added compacted montmorillonite was investigated by through-diffusion experiment. The obtained distribution coefficient of Cs for the illite-added compacted montmorillonite was several times larger than that for the montmorillonite without illite, while no increase of effective diffusion coefficient was observed for the illite-added compacted montmorillonite. The dominant sorption site of Cs on illite is considered to be the frayed edge site (FES) considering the Cs concentration in this experiment. Therefore, the surface diffusion of Cs sorbing on the FES on illite surface was considered to be negligible in compacted montmorillonite.

Journal Articles

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03

The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.

Journal Articles

Development of advanced inductive scenarios for ITER

Luce, T. C.*; Challis, C. D.*; Ide, Shunsuke; Joffrin, E.*; Kamada, Yutaka; Politzer, P. A.*; Schweinzer, J.*; Sips, A. C. C.*; Stober, J.*; Giruzzi, G.*; et al.

Nuclear Fusion, 54(1), p.013015_1 - 013015_15, 2013/12

 Times Cited Count:29 Percentile:82.73(Physics, Fluids & Plasmas)

JAEA Reports

Studies about strength recovery and generalized relaxation behavior of rock, 5

Sanada, Masanori; Kishi, Hirokazu*; Sugita, Yutaka; Hayashi, Katsuhiko*; Takebe, Atsuji*; Okubo, Seisuke*

JAEA-Research 2012-025, 130 Pages, 2012/09


In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, by using the value of a suitable constant with the constitutive equation showing strength recovery, it was showed that change of the axial stress in a compacting test could be expressed. About the generalized relaxation, it examined by the air dried and the saturated condition. Visco-elastic behavior was more remarkable in saturated condition than the air dried. Moreover, when the loading rate up to the starting point of the generalized relaxation test was large, the influence on visco-elastic behavior was remarkable. About tensile characteristics, a splitting tensile strength test and a uniaxial tensile strength test were carried out. About splitting tensile strength, it turned out that the influence of the loading direction on a bedding plane is great.

JAEA Reports

Studies on the design method of multi tunnels in geological disposal facility, 5

Sanada, Masanori; Kishi, Hirokazu; Hayashi, Katsuhiko*; Takebe, Atsuji*

JAEA-Research 2011-055, 79 Pages, 2012/03


In order to refine and rationalize a design method of multi tunnels in the deep geological repository, various study have been conducted. In this study, an effect of procedure for excavating multi-tunnels on extent of EDZ was examined by 3D FEM analysis. In modeling the multi tunnels and setting cases of analysis, workability, cost and safeness under construction were considered. Results of 3D FEM analysis showed that 3D effect of procedure for excavating such as a gap of progress with tunnel faces can be considered by 3D FEM and extent of EDZ is demonstrated more practically compared with 2D FEM. Another 2D FEM analysis modeling for crystalline rock (granite) was executed and the results showed that plastic zone did not appear in all cases.

JAEA Reports

Studies about strength recovery and generalized relaxation behavior of rock, 4

Sanada, Masanori; Hayashi, Katsuhiko*; Kishi, Hirokazu; Takebe, Atsuji*; Okubo, Seisuke*

JAEA-Research 2011-028, 102 Pages, 2011/11


In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, recovery of failed rocks in strength and hydraulic conductivity were observed under a certain condition. We believe this result is very important for the stability evaluation of underground space in the bedrock that needs good sealing up characteristic, isolation characteristic, safety and high reliability for long term. Generalized stress relaxation test was conducted submerging samples in water. Experimental results showed comparatively smaller scatter than those in air-dried condition. It was also found that testing results were affected by strain rate up to the starting point of generalized relaxation test. Indirect and uniaxial tensile strength tests were also conducted submerging samples in water and smaller tensile strength with smaller scatter were obtained than those in air-dried condition.

Journal Articles

Recent activities of R&D on effects of tritium water on confinement materials and tritiated water processing

Yamanishi, Toshihiko; Hayashi, Takumi; Iwai, Yasunori; Isobe, Kanetsugu; Hara, Masanori*; Sugiyama, Takahiko*; Okuno, Kenji*

Fusion Engineering and Design, 86(9-11), p.2152 - 2155, 2011/10

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

It is quite significant subject how to confine the tritium in a fusion reactor. Especially, it is strongly desired to get the data for tritiated water. This is because tritiated water is much hazardous than the hydrogen form of tritium. As for the behavior of high concentration tritium water, we could get a series of valuable data for the corrosion of the tritiated water against metal materials. In the case where a metal material is in water, an oxidized layer is formed at the surface of the metal. The oxidized layer functions as a passive layer for the corrosion. However, it has been observed that the formation of the oxidized layer was prevented by the presence of tritium in water (0.23 GBq/cc). The chemical exchange column has been applied in ITER as the tritium recovery system from tritiated water. A set of data for an advanced chemical exchange column has been obtained.

Journal Articles

Recent progress in blanket materials development in the Broader Approach Activities

Nishitani, Takeo; Tanigawa, Hiroyasu; Nozawa, Takashi; Jitsukawa, Shiro; Nakamichi, Masaru; Hoshino, Tsuyoshi; Yamanishi, Toshihiko; Baluc, N.*; M$"o$slang, A.*; Lindou, R.*; et al.

Journal of Nuclear Materials, 417(1-3), p.1331 - 1335, 2011/10

 Times Cited Count:14 Percentile:72.54(Materials Science, Multidisciplinary)

As a part of the Broader Approach (BA) activities, the research and development on blanket related materials and tritium technology have been initiated toward DEMO by Japan and EU. Recently, those five R&D items have progressed substantially in Japan and EU. As a preparatory work aiming at the RAFM steel muss-production development, a 5-ton heat of RAFM steel (F82H) was procured with the Electro Slag Re-melting as a secondary melting. The result of the double notch tensile test method for the NITE-SiC$$_{f}$$/SiC specimen indicated notch insensitivity and very minor size effect on proportional limit tensile stress and fracture strength. For the fabrication technology development of beryllide neutron multiplayer pebbles, Be- Ti inter-metallic pebbles have been sintered directly from the mixed powder of Be and Ti in Japan.

JAEA Reports

Document collection of the 22nd Technical Special Committee on Fugen Decommissioning

Kutsuna, Hideki; Matsumori, Akira*; Izumi, Masanori; Hayashi, Hirokazu; Higashiura, Norikazu

JAEA-Review 2011-025, 43 Pages, 2011/07


In planning and carrying out our decommissioning technical development, "Technical special committee on Fugen decommissioning", which consists of the members well-informed, is established, aiming to make good use of Fugen as a place for technological development which is opened inside and outside the country, as the central point in the energy research and development base making project of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report compiles presentation materials "Current Situation of Fugen Decommissioning", "Radioactive Corrosion Products (CP) Decontamination Experiment with Heavy Water System Equipment", "Application of management data evaluation system to Fugen", "Preparatory Situation for Operation of Clearance System" of the 22nd Technical special committee on Fugen decommissioning which held on September 14, 2010.

Journal Articles

Integrated modeling of steady-state scenarios and heating and current drive mixes for ITER

Murakami, Masanori*; Park, J. M.*; Giruzzi, G.*; Garcia, J.*; Bonoli, P.*; Budny, R. V.*; Doyle, E. J.*; Fukuyama, Atsushi*; Hayashi, Nobuhiko; Honda, Mitsuru; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

Journal Articles

Progress of IFERC project in the Broader Approach activities

Araki, Masanori; Sakamoto, Yoshiteru; Hayashi, Kimio; Nishitani, Takeo; Ouchi, Rei*

Fusion Engineering and Design, 85(10-12), p.2196 - 2202, 2010/12

 Times Cited Count:10 Percentile:56.7(Nuclear Science & Technology)

For contributing to the ITER project and promoting a possible early realization of DEMO, the IFERC project shall perform the activities on (1) DEMO Design and R&D Coordination, (2) Computational Simulation Centre, and (3) ITER Remote Experimentation Centre in the framework under the BA agreement. The DEMO design activity aims at establishing a common basis for DEMO design, including design features of DEMO, a possible common concept of DEMO, a roadmap for DEMO, and so on. Based on the common interest toward DEMO, the DEMO R&D activities have been planned and carried out for the following five areas which are relevant to blanket development: (1) SiC/SiC composites, (2) tritium technology, (3) materials engineering for DEMO blanket, (4) advanced neutron multiplier for DEMO blanket, and (5) advanced tritium breeders for DEMO blanket. In the activity of the Computational Simulation Centre, the objective is to provide and exploit a supercomputer for large scale simulation activities to analyse experimental data on fusion plasmas, prepare scenarios for ITER operation, predict the performance of the ITER facilities and contribute to the DEMO design. At the initial phase, high-level benchmark codes in the fusion research field have been selected through Special Working Group.

Journal Articles

Incommensurate spin correlations induced by magnetic Fe ions substituted into overdoped Bi$$_{1.75}$$Pb$$_{0.35}$$Sr$$_{1.90}$$CuO$$_{6+z}$$

Hiraka, Haruhiro*; Hayashi, Yoichiro*; Wakimoto, Shuichi; Takeda, Masayasu; Kakurai, Kazuhisa; Adachi, Tadashi*; Koike, Yoji*; Yamada, Ikuya*; Miyazaki, Masanori*; Hiraishi, Masatoshi*; et al.

Physical Review B, 81(14), p.144501_1 - 144501_6, 2010/04

 Times Cited Count:15 Percentile:55.36(Materials Science, Multidisciplinary)

Journal Articles

International Fusion Energy Research Centre

Araki, Masanori; Hayashi, Kimio; Tobita, Kenji; Nishitani, Takeo; Tanigawa, Hiroyasu; Nozawa, Takashi; Yamanishi, Toshihiko; Nakamichi, Masaru; Hoshino, Tsuyoshi; Ozeki, Takahisa; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 86(4), p.231 - 239, 2010/04

The Broader Approach Activities, which support the ITER Project and implement activities to aim early realization of fusion energy, is an EU-Japan collaborative project to carry out various kinds of researches and developments during the period of the ITER construction phase. In this special topic, achievements and prospects of the projects on the International Fusion Energy Research Centre (IFERC) is described.

Journal Articles

Tritium science and technology for fusion reactor, 6; Studies on chemical phenomena of high concentration tritium water and organic compounds of tritium from viewpoint of the tritium confinement

Yamanishi, Toshihiko; Hayashi, Takumi; Iwai, Yasunori; Isobe, Kanetsugu; Hara, Masanori*; Sugiyama, Takahiko*; Okuno, Kenji*

Purazuma, Kaku Yugo Gakkai-Shi, 85(10), p.716 - 725, 2009/10

In a fusion reactor, tritium must be handled in a vacuum vessel, a fuel cycle, and other systems. It is quite significant subject how to confine the tritium in these systems. ITER is the first machine in the world where the tritium confinement would be demonstrated. It is essential to establish a series of database for tritium handling technology to analyze the data obtained at ITER. Especially, it is strongly desired to get the data for tritium water. This is because tritium water is much hazardous than the hydrogen form of tritium. For these reasons, our attention is focused on the study on the behavior of tritium water in the fuel cycle system and structural materials of the system. As for the behavior of high concentration tritium water, we could get the first series of valuable data for the corrosion of the tritium water against metal materials in the world. The behavior of tritium in a surface area of metal and organic compounds was also discussed. As for tritium recovery from tritium water, we could get the data on an advanced chemical exchange column. The chemical exchange column has been applied in ITER as the tritium recovery system from tritium water. Our data showed that the column performance could be remarkably improved. Tritium durability and catalyst tests have also been carried out for the chemical exchange column. Some other possible method for the tritium recovery has also been studied such as an advance adsorption method.

Journal Articles

Fusion materials development program in the Broader Approach activities

Nishitani, Takeo; Tanigawa, Hiroyasu; Jitsukawa, Shiro; Nozawa, Takashi; Hayashi, Kimio; Yamanishi, Toshihiko; Tsuchiya, Kunihiko; M$"o$slang, A.*; Baluc, N.*; Pizzuto, A.*; et al.

Journal of Nuclear Materials, 386-388, p.405 - 410, 2009/04

 Times Cited Count:31 Percentile:88.29(Materials Science, Multidisciplinary)

The establishment of the breeding blanket technology is one of the most important engineering issues on the DEMO development. For the DEMO blanket, developments of the structural materials and functional materials such as tritium breeder and neutron multiplier. Which should be used under the savior circumstance such as high neutron fluence, high temperature and strong magnetic field, are urgent issues. In the Broader Approach activities initiated by EU and Japan, developments of reduced activation ferritic martensitic steels as a DEMO blanket structural material, SiC/SiC composites, advanced tritium breeders and neutron multiplier for DEMO blankets, are planed as common interest issues of EU and Japan. This paper describes the overview of the development program.

Journal Articles

The 2008 public release of the international multi-tokamak confinement profile database

Roach, C. M.*; Walters, M.*; Budny, R. V.*; Imbeaux, F.*; Fredian, T. W.*; Greenwald, M.*; Stillerman, J. A.*; Alexander, D. A.*; Carlsson, J.*; Cary, J. R.*; et al.

Nuclear Fusion, 48(12), p.125001_1 - 125001_19, 2008/12

 Times Cited Count:35 Percentile:28.57(Physics, Fluids & Plasmas)

This paper documents the public release PR08 of the International Tokamak Physics Activity profile database, which should be of particular interest to the magnetic confinement fusion community. Data from a wide variety of interesting discharges from many of the world's leading tokamak experiments are now made available in PR08, which also includes predictive simulations of an initial set of operating scenarios for ITER. In this paper we describe the discharges that have been included and the tools that are available to the reader who is interested in accessing and working with the data.

Journal Articles

Geometric isotope effect on the N$$_2$$H$$_{7}$$$$^{+}$$ cation and N$$_2$$H$$_{5}$$$$^{-}$$ anion by ${it ab initio}$ path integral molecular dynamics simulation

Ishibashi, Hiroaki*; Hayashi, Aiko*; Shiga, Motoyuki; Tachikawa, Masanori*

ChemPhysChem, 9(3), p.383 - 387, 2008/02

 Times Cited Count:24 Percentile:64.74(Chemistry, Physical)

no abstracts in English

Journal Articles

Progress in the ITER physics basis, 6; Steady state operation

Gormezano, C.*; Sips, A. C. C.*; Luce, T. C.*; Ide, Shunsuke; Becoulet, A.*; Litaudon, X.*; Isayama, Akihiko; Hobirk, J.*; Wade, M. R.*; Oikawa, Toshihiro; et al.

Nuclear Fusion, 47(6), p.S285 - S336, 2007/06

 Times Cited Count:302 Percentile:77.19(Physics, Fluids & Plasmas)

This paper reviews recent world-wide progress in physics research towards International Thermonuclear Reactor (ITER). This chaper descrives on steady state operation with emphasis on: integrated scenarios, review of presently developed experimental scenarios, actuators for steady state operation, specific control issues to steady state operation, simulation of ITER steady-state and hybrid scenarios.

Journal Articles

H/D isotope effect on the dihydrogen bond by $$ab initio$$ path integral molecular dynamics simulation

Hayashi, Aiko*; Shiga, Motoyuki; Tachikawa, Masanori*

Molecular Simulation, 33(1-2), p.185 - 188, 2007/02

 Times Cited Count:3 Percentile:9.28(Chemistry, Physical)

Ab initio path integral molecular dynamics simulation has been performed to investigate the lithium-hydrogen bond and dihydrogen bond of C$$_2$$H$$_2$$$$cdot$$LiH complex. It has been found from the simulation that these unusual types of hydrogen bonds have large geometrical isotope effect which is similar to that of the conventional hydrogen bonding.

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