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Journal Articles

Diffusion and sorption behavior of HTO, Cs, I and U in mortar

Akagi, Yosuke*; Kato, Hiroyasu*; Tachi, Yukio; Sakamoto, Hiroyuki*

Progress in Nuclear Science and Technology (Internet), 5, p.233 - 236, 2018/11

A large amount of radioactive contaminated concrete will be generated from the decommissioning in the Fukushima Dai-ichi Nuclear Power Plant (NPP). For developing the plans of decommissioning and waste management including decontamination and disposal, it is important to estimate radionuclides inventory and concentration distribution in the concrete materials. In this study, effective diffusivities (De) and distribution coefficients (Kd) of HTO, Cs, I and U in OPC mortar were measured by through-diffusion and batch sorption experiments. De values derived were in the sequence of HTO, I, Cs, U, implying that cation exclusion effects may be important mechanisms in OPC mortar. Kd values derived by batch tests were higher by more than one order of magnitude than the diffusion-derived Kd values, indicating that crushing of samples had a strong influence on sorption. Diffusion and sorption mechanisms in OPC mortar were evaluated to predict the penetration behavior of these radionuclides.

Journal Articles

Design study of a neutral beam injector for fusion DEMO plant at JAERI

Inoue, Takashi; Hanada, Masaya; Kashiwagi, Mieko; Nishio, Satoshi; Sakamoto, Keishi; Sato, Masayasu; Taniguchi, Masaki; Tobita, Kenji; Watanabe, Kazuhiro; DEMO Plant Design Team

Fusion Engineering and Design, 81(8-14), p.1291 - 1297, 2006/02

 Times Cited Count:10 Percentile:59.81(Nuclear Science & Technology)

Requirement and technical issues of the neutral beam inejctor (NBI) is discussed for fusion DEMO plant. The NBI for the fusion DEMO plant should be high efficiency, high energy and high reliability with long life. From the view point of high efficiency, use of conventional electrostatic accelerator is realistic. Due to operation under radiation environment, vacuum insulation is essential in the accelerator. According to the insulation design guideline, it was clarified that the beam energy of 1.5$$sim$$2 MeV is possible in the accelerator. Development of filamentless, and cesium free ion source is required, based on the existing high current/high current density negative ion production technology. The gas neutralization is not applicable due to its low efficiency (60%). R&D on an advanced neutralization scheme such as plasma neutralization (efficiency: $$>$$80%) is required. Recently, development of cw high power semiconductor laser is in progress. The paper shows a conceptual design of a high efficiency laser neutralizer utilizing the new semiconductor laser array.

Journal Articles

First wall and divertor engineering research for power plant in JAERI

Suzuki, Satoshi; Ezato, Koichiro; Hirose, Takanori; Sato, Kazuyoshi; Yoshida, Hajime; Enoeda, Mikio; Akiba, Masato

Fusion Engineering and Design, 81(1-7), p.93 - 103, 2006/02

 Times Cited Count:12 Percentile:65.95(Nuclear Science & Technology)

This paper presents an R&D activity on the plasma facing components (PFCs), such as first wall and divertor, for the fusion power plant. The PFCs of the power plant will be subjected to heavy neutron irradiation and high heat/particle flux from plasma during the continuous operation. In the present design of the PFCs, the candidate structural material is a reduced activation ferritic-martensitic steel, F82H, from the viewpoints of low activation and high robustness against neutron irradiation, and the candidate armor material is tungsten from the low sputtering yield and low tritium retention points of view. To realize the PFCs using such materials, JAERI has bee extensively conducting R&Ds on; (1) high performance cooling tube, (2) tungsten armor materials, (3) selection of a bonding technique for F82H and tungsten materials and (4) evaluation of structural integrity. Recent achievements on these R&Ds are presented.

Journal Articles

An Approach for development of technical structural standard in ITER

Nakahira, Masataka; Takeda, Nobukazu

Hozengaku, 4(4), p.47 - 52, 2006/01

The technical structural standard for ITER (International Thermonuclear Experimental Fusion Reactor) should be innovative because of their quite different features of safety and mechanical components from nuclear fission reactors, and the necessity of introducing several new fabrication and examination technologies. Recognizing the international importance of Fusion Standard, Japan and ASME has started the cooperation development of the Fusion Standard. This paper shows the special features of ITER from view points of safety, design and fabrication, and proposes approach for development of the fusion standard.

JAEA Reports

Annual report of Naka Fusion Research Establishment from April 1, 2004 to March 31, 2005

Naka Fusion Research Establishment

JAERI-Review 2005-046, 113 Pages, 2005/09

JAERI-Review-2005-046.pdf:24.35MB

This annual report provides an overview of research and development activities at Naka Fusion Research Establishment, including those performed in collaboration with other research establishments of JAERI, research institutes, and universities, during the period from 1 April, 2004 to 31 March, 2005. The activities in the Naka Fusion Research Establishment are highlighted by researches in JT-60 and JFT-2M, theoretical and analytical plasma researches, research and development of fusion reactor technologies towards ITER and fusion power demonstration plants, and activities in support of ITER design and construction.

Journal Articles

Development of advanced Nb$$_{3}$$Al superconductors for a fusion demo plant

Koizumi, Norikiyo; Takeuchi, Takao*; Okuno, Kiyoshi

Nuclear Fusion, 45(6), p.431 - 438, 2005/06

 Times Cited Count:29 Percentile:69.28(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Development of advanced Nb$$_{3}$$Al superconductors for a fusion demo plant

Koizumi, Norikiyo; Takeuchi, Takao*; Okuno, Kiyoshi

Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11

no abstracts in English

JAEA Reports

Study on system integration of robots Operated in nuclear fusion facility and nuclear power plant facilities

Oka, Kiyoshi

JAERI-Research 2004-009, 225 Pages, 2004/07

JAERI-Research-2004-009.pdf:47.47MB

In the present paper, I describe the necessary approaches and elemental technologies to solve the issues on the system integration of the typical robot systems for maintenance in the nuclear fusion facility and rescue in the accident of the nuclear power plant facilities. These robots work under the intense radiation condition and restricted space in place of human. In particular, I propose a new approach to realize the system integration of the robot for actual use from the viewpoints of not only the environmental and working conditions but also the restructure and optimization of the required elemental technologies with a well balance in the robot system. Based on the above approach, I have a contribution to realize the robot systems working under the actual conditions for maintenance in the nuclear fusion facility and rescue in the accident of the nuclear power plant facilities.

Journal Articles

Electric power flow in a nuclear fusion power plant

Matsukawa, Makoto; Tobita, Kenji; Chikaraishi, Hirotaka*; Sagara, Akio*; Norimatsu, Takayoshi*

Purazuma, Kaku Yugo Gakkai-Shi, 80(7), p.559 - 562, 2004/07

Final purpose of the fusion energy development is to utilize the produced fusion power mainly as electric power for the easiness of transmission and conversion. In spite of the type of fusion power plant, large circulating electric power should exist in the plant for the plasma heating, current drive. This paper describes the electric power flow in the nuclear fusion power plants to be built as the DEMO reactor beyond ITER. Here, the necessity of the local energy storage and high efficient converter will be also discussed.

JAEA Reports

Annual report of Naka Fusion Research Establishment from April 1, 2002 to March 31, 2003

Naka Fusion Research Establishment

JAERI-Review 2003-035, 129 Pages, 2003/11

JAERI-Review-2003-035.pdf:13.55MB

This annual report provides an overview of research and development (R&D) activities at Naka Fusion Research Establishment in collaboration with other research establishment of JAERI, research institutes, and universities during the period from 1 April, 2002 to 31 March, 2003. The activities in the Naka Fusion Research Establishment are highlighted by high performance plasma researches in JT-60 and JFT-2M, R&D of fusion reactor technologies towards ITER and fusion power demonstration plants, and activities in support of ITER design and construction.

JAEA Reports

Measurement and evaluation of isotope effect between tritium and deuterium on diffusion and surface recombination in/on nickel using ion driven permeation method (Cooperative research)

Nakamura, Hirofumi; Nishi, Masataka; Sugisaki, Masayasu*

JAERI-Research 2003-018, 32 Pages, 2003/09

JAERI-Research-2003-018.pdf:1.32MB

Tritium transport behavior in materials, which is essential for the safety evaluation of the fusion reactor, has to be evaluated by either tritium properties or extrapolated value from protium or deuterium (D) to tritium (T) using the isotope effect theory. However, there are still some uncertainties on estimation of T behavior in materials, because there are only a few T transport properties data in materials, and it is not completely proven the application of the isotope effect theory to T due to the lack of T data. Therefore, in order to understand the tritium transport properties in materials, isotope effects on diffusion and surface recombination between T and D in/on nickel, whose hydrogen transport properties were well known, were investigated by comparing the obtained properties of T with those of D measured under the same conditions with the ion driven permeation method. Though obtained diffusion coefficient of T was larger than that of D, and activation energy of diffusion of T was smaller than that of D as the contrary to the classical diffusion theory, those were shown to be explained with a modified diffusion theory by introducing higher vibration temperatures in nickel than previous reported values. In addition, the isotope effect on surface recombination coefficient between D and T was shown to be explained using a modified solution model as well as diffusion.

Journal Articles

Development of supercritical pressure water cooled solid breeder blanket in JAERI

Akiba, Masato; Ishitsuka, Etsuo; Enoeda, Mikio; Nishitani, Takeo; Konishi, Satoshi

Purazuma, Kaku Yugo Gakkai-Shi, 79(9), p.929 - 934, 2003/09

no abstracts in English

Journal Articles

Present research status on divertor and plasma facing components for fusion power plants

Suzuki, Satoshi; Ueda, Yoshio*; Tokunaga, Kazutoshi*; Sato, Kazuyoshi; Akiba, Masato

Fusion Science and Technology, 44(1), p.41 - 48, 2003/07

 Times Cited Count:22 Percentile:81.33(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Exchange of tritium implanted into oxide ceramics for protium by exposure to air vapors at room temperature

Morita, Kenji*; Suzuki, Hironori*; Soda, Kazuo*; Iwahara, Hiroiku*; Nakamura, Hirofumi; Hayashi, Takumi; Nishi, Masataka

Journal of Nuclear Materials, 307-311(2), p.1461 - 1465, 2002/12

 Times Cited Count:2 Percentile:17.59(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Implantation driven permeation behavior of deuterium through pure tungsten

Nakamura, Hirofumi; Hayashi, Takumi; Nishi, Masataka; Arita, Makoto; Okuno, Kenji*

Fusion Engineering and Design, 55(4), p.513 - 520, 2001/09

 Times Cited Count:8 Percentile:54.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Impact of supersonic versus propeller wind data on dispersion estimates for nuclear plants

S.J.Hu*; ; Kobayashi, Hideo

Health Physics, 61(6), p.831 - 835, 1991/12

 Times Cited Count:2 Percentile:32.61(Environmental Sciences)

no abstracts in English

JAEA Reports

JAEA Reports

Data Compilation for Depth Distribution of Ion-Induced Damage and Ion-Implanted Atoms

*; *; Ozawa, K.

JAERI-M 84-092, 144 Pages, 1984/05

JAERI-M-84-092.pdf:2.61MB

no abstracts in English

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