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Journal Articles

Predoping effects of boron and phosphorous on arsenic diffusion along grain boundaries in polycrystalline silicon investigated by atom probe tomography

Takamizawa, Hisashi; Shimizu, Yasuo*; Inoue, Koji*; Nozawa, Yasuko*; Toyama, Takeshi*; Yano, Fumiko*; Inoue, Masao*; Nishida, Akio*; Nagai, Yasuyoshi*

Applied Physics Express, 9(10), p.106601_1 - 106601_4, 2016/10

 Times Cited Count:0 Percentile:0(Physics, Applied)

Journal Articles

Hydrogen generation by water radiolysis with immersion of oxidation products of zircaloy-4

Matsumoto, Yoshinobu*; Do, Thi-Mai-Dung*; Inoue, Masao; Nagaishi, Ryuji; Ogawa, Toru

Journal of Nuclear Science and Technology, 52(10), p.1303 - 1307, 2015/10

 Times Cited Count:3 Percentile:32.14(Nuclear Science & Technology)

Effects of zirconium oxides and oxidation products of zircaloy-4 on water radiolysis were investigated to predict the hydrogen generation from the water-immersed debris after a severe accident of a nuclear power plant. Observed yields of hydrogen in water containing the oxides were measured as a function of their weight fractions. Assuming that energies of Co-60 $$gamma$$-ray deposited to water and the oxides brought about the water radiolysis to generate hydrogen independently, the radiolysis showed an additional term of hydrogen generation due to the energy deposition to the oxides. This term seemed to be dependent on the specific surface area or particle size of oxides, but not on the crystal structure of oxides in our experimental results. The oxides in distilled water gave the strong enhancement of term. The enhancement tended to saturate with increasing the weight fraction of oxides and was not apparent in the seawater.

Journal Articles

Consideration of radiolytic behavior in diluted and concentrated systems of seawater for computational simulation of hydrogen generation

Nagaishi, Ryuji; Inoue, Masao; Hino, Ryutaro; Ogawa, Toru

Proceedings of 2014 Nuclear Plant Chemistry Conference (NPC 2014) (USB Flash Drive), 9 Pages, 2014/10

Since seawater has been used as a coolant for reactors and spent fuel pools in broken reactor buildings at Fukushima Daiichi NPS accident, radioactive contaminated water emitted following the accident has contained salt content of seawater at high concentrations, different from that at TMI-2 accident. Radiolysis of seawater leading to hydrogen generation and corrosion has been simulated and reported by several groups. However, the proposed radiolysis models cannot be always applied to water radiolysis at the wide range of salt concentrations present in the NPS, mainly because primary yields of radiolysis products of water and radiation-induced reactions are dependent on the salt concentration. In this study, the radiolytic behavior in diluted and concentrated systems of seawater was considered on the basis of results in steady state and pulse radiolysis experiments, in which the above salt effects were demonstrated from the obtained results.

Journal Articles

Origin of non-uniformity of the source plasmas in JT-60 negative ion source

Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Inoue, Takashi; Kashiwagi, Mieko; Grisham, L. R.*; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; et al.

Plasma and Fusion Research (Internet), 8(Sp.1), p.2405146_1 - 2405146_4, 2013/11

Distributions of H$$^{0}$$ and H$$^{+}$$ in the source plasmas produced at the end-plugs of JT-60 negative ions source were measured by Langmuir probes and emission spectroscopy in order to experimentally investigate the cause of lower density of the negative ions extracted from end-plugs in the source. Densities of H$$^{0}$$ and H$$^{+}$$ in end-plugs of the plasma grid in the source were compared with those in the center regions. As a result, lower density of the negative ion at the edge was caused by lower beam optics due to lower and higher density of the H$$^{0}$$ and H$$^{+}$$.

Journal Articles

Development of soil amendment by radiation processing and its application to sandy soil

Inoue, Mitsuhiro*; Nagasawa, Naotsugu; Tamada, Masao

Nohon Sakyu Gakkai-Shi, 59(2), p.61 - 70, 2012/11

no abstracts in English

Journal Articles

Role of safeguards in proliferation resistance for the future nuclear fuel cycle systems

Kuno, Yusuke; Senzaki, Masao; Seya, Michio; Inoue, Naoko

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 11 Pages, 2012/00

A large amount of plutonium as well as high $$^{239}$$Pu should be handled in the future fast reactor nuclear fuel cycle (FR-NFC), where very robust measures for nuclear proliferation-resistance (PR) may have to be taken to prevent nuclear proliferation. To find a good balance of extrinsic barrier and intrinsic one will come to be essential for NFC designers to optimize civilian nuclear technology with nuclear non-proliferation. International Safeguards including Comprehensive Safeguards Agreement and Additional Protocol is the most effective institutional barrier among other institutional measures in non-proliferation regime. The advanced Safeguards with high detectability can play a dominant role for PR in the states complying with full institutional controls. In this context, a new concept of differentiation in the intrinsic measures depending upon the level of Safeguards could be applied from the viewpoint of plant design rationalization.

JAEA Reports

Introduction to the Revision 5 of Evaluation Methodology for Proliferation Resistance and Physical Protection of Generation IV Nuclear Energy Systems

Kawakubo, Yoko; Inoue, Naoko; Senzaki, Masao

JAEA-Review 2011-024, 75 Pages, 2011/12

JAEA-Review-2011-024.pdf:3.61MB

Revision 5 of the "Evaluation Methodology for Proliferation Resistance and Physical Protection of Generation IV Nuclear Energy Systems" is also known as the Rev. 5 report. The Rev. 5 report provides an important evaluation framework that was developed with consensus-based discussions, and published by the OECD-NEA in November, 2006. The activities of PR&PP WG has contributed to establish PR&PP culture. Japan has to develop the future nuclear cycle system with sufficient proliferation resistance and physical protection features and demonstrate and explain about its effectiveness to the domestic and international society. For these reasons, and recognizing the usefulness of the Revision-5 Report, it was translated and published here as a Japanese-language edition with the concurrence of the OECD-NEA. The original report in English language can be downloaded at the OECD-NEA website.

Journal Articles

Progress in development and design of the neutral beam injector for JT-60SA

Hanada, Masaya; Kojima, Atsushi; Tanaka, Yutaka; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; et al.

Fusion Engineering and Design, 86(6-8), p.835 - 838, 2011/10

 Times Cited Count:8 Percentile:58.2(Nuclear Science & Technology)

Neutral beam (NB) injectors for JT-60 Super Advanced (JT-60SA) have been designed and developed. Twelve positive-ion-based and one negative-ion-based NB injectors are allocated to inject 30 MW D$$^{0}$$ beams in total for 100 s. Each of the positive-ion-based NB injector is designed to inject 1.7 MW for 100s at 85 keV. A part of the power supplies and magnetic shield utilized on JT-60U are upgraded and reused on JT-60SA. To realize the negative-ion-based NB injector for JT-60SA where the injection of 500 keV, 10 MW D$$^{0}$$ beams for 100s is required, R&Ds of the negative ion source have been carried out. High-energy negative ion beams of 490-500 keV have been successfully produced at a beam current of 1-2.8 A through 20% of the total ion extraction area, by improving voltage holding capability of the ion source. This is the first demonstration of a high-current negative ion acceleration of $$>$$1 A to 500 keV. The design of the power supplies and the beamline is also in progress. The procurement of the acceleration power supply starts in 2010.

Journal Articles

Development of the JT-60SA Neutral Beam Injectors

Hanada, Masaya; Kojima, Atsushi; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; Kazawa, Minoru; et al.

AIP Conference Proceedings 1390, p.536 - 544, 2011/09

 Times Cited Count:5 Percentile:77.65

no abstracts in English

Journal Articles

Achievement of 500 keV negative ion beam acceleration on JT-60U negative-ion-based neutral beam injector

Kojima, Atsushi; Hanada, Masaya; Tanaka, Yutaka*; Kawai, Mikito*; Akino, Noboru; Kazawa, Minoru; Komata, Masao; Mogaki, Kazuhiko; Usui, Katsutomi; Sasaki, Shunichi; et al.

Nuclear Fusion, 51(8), p.083049_1 - 083049_8, 2011/08

 Times Cited Count:42 Percentile:88.1(Physics, Fluids & Plasmas)

Hydrogen negative ion beams of 490 keV, 3 A and 510 keV, 1 A have been successfully produced in the JT-60 negative ion source with three acceleration stages. These successful productions of the high-energy beams at high current have been achieved by overcoming the most critical issue, i.e., a poor voltage holding of the large negative ion sources with the grids of 2 m$$^{2}$$ for JT-60SA and ITER. To improve voltage holding capability, the breakdown voltages for the large grids was examined for the first time. It was found that a vacuum insulation distance for the large grids was 6-7 times longer than that for the small-area grid (0.02 m$$^{2}$$). From this result, the gap lengths between the grids were tuned in the JT-60 negative ion source. The modification of the ion source also realized a significant stabilization of voltage holding and a short conditioning time. These results suggest a practical use of the large negative ion sources in JT-60SA and ITER.

Journal Articles

Demonstration of 500 keV beam acceleration on JT-60 negative-ion-based neutral beam injector

Kojima, Atsushi; Hanada, Masaya; Tanaka, Yutaka*; Kawai, Mikito*; Akino, Noboru; Kazawa, Minoru; Komata, Masao; Mogaki, Kazuhiko; Usui, Katsutomi; Sasaki, Shunichi; et al.

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

Hydrogen negative ion beams of 490keV, 3A and 510 keV, 1A have been successfully produced in the JT-60 negative ion source with three acceleration stages. These successful productions of the high-energy beams at high current have been achieved by overcoming the most critical issue, i.e., a poor voltage holding of the large negative ion sources with the grids of $$sim$$ 2 m$$^{2}$$ for JT-60SA and ITER. To improve voltage holding capability, the breakdown voltages for the large grids was examined for the first time. It was found that a vacuum insulation distance for the large grids was 6-7 times longer than that for the small-area grid (0.02 m$$^{2}$$). From this result, the gap lengths between the grids were tuned in the JT-60 negative ion source. The modification of the ion source also realized a significant stabilization of voltage holding and a short conditioning time. These results suggest a practical use of the large negative ion sources in JT-60 SA and ITER.

Journal Articles

The Status of proliferation resistance evaluation methodology development in GEN IV International Forum

Inoue, Naoko; Kawakubo, Yoko; Seya, Michio; Suzuki, Mitsutoshi; Kuno, Yusuke; Senzaki, Masao

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-31-Kai Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2010/12

The GIF Proliferation Resistance and Physical Protection (PR&PP) evaluation methodology has been developed for GEN IV nuclear energy systems under the international consensus. The PR&PP WG activities include development of the measures and metrics; establishment of the framework of PR&PP evaluation, the demonstration study using Example Sodium Fast Reactor (ESFR), which included the development of three evaluation approaches; the Case study using ESFR and four kinds of threat scenarios; the joint study with GIF System Steering Committees (SSCs) of the six reactor design concepts; and the harmonization study with the IAEA's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). This paper reviews the status of GIF PR&PP studies and identifies the challenges and directions for applying the methodology to evaluate future nuclear energy systems in Japan.

JAEA Reports

Development of measuring instruments for material irradiation tests

Kitagishi, Shigeru; Tanimoto, Masataka; Iimura, Koichi; Inoue, Shuichi; Saito, Takashi; Omi, Masao; Tsuchiya, Kunihiko

JAEA-Review 2010-046, 19 Pages, 2010/11

JAEA-Review-2010-046.pdf:2.51MB

The Japan Materials Testing Reactor (JMTR) has been utilized for the various neutron irradiation tests of fuels and materials, as well as for radioisotope production since achieving the first criticality in March 1968. The operation of JMTR was halted for the refurbishment in August 2006. The new JMTR is expected to contribute to many fields: the lifetime extension of LWRs and the expansion of industry use. To meet a wide range of users' needs, the development of new irradiation technologies has been carried out for the new JMTR. This report summarizes the present conditions of the development of FP gas pressure gauges, multi-paired thermocouples, ECP and ceramics sensors.

Journal Articles

Development and design of the negative-ion-based NBI for JT-60 Super Advanced

Hanada, Masaya; Akino, Noboru; Endo, Yasuei; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Kojima, Atsushi; Mogaki, Kazuhiko; et al.

Journal of Plasma and Fusion Research SERIES, Vol.9, p.208 - 213, 2010/08

A large negative ion source with an ion extraction area of 110 cm $$times$$ 45 cm has been developed to produce 500 keV, 22 A D$$^{-}$$ ion beams required for JT-60 Super Advanced. To realize the JT-60SA negative ion source, the JT-60 negative ion source has been modified and tested on the negative-ion-based neutral beam injector on JT-60U. A 500 keV H$$^{-}$$ ion beam has been produced at 3 A without a significant degradation of beam optics. This is the first demonstration of a high energy negative ion acceleration of more than one-ampere to 500 keV in the world. The beam current density of 90 A/m$$^{2}$$ is being increased to meet 130 A/m$$^{2}$$ of the design value for JT-60SA by tuning the operation parameters. A long pulse injection of 30 s has been achieved at a injection D$$^{0}$$ power of 3 MW. The injection energy, defined as the product of the injection time and power, reaches 80 MJ by neutralizing a 340 keV, 27 A D$$^{-}$$ ion beam produced with two negative ion sources.

Journal Articles

A Consideration on proliferation resistance of a FBR fuel cycle system

Inoue, Naoko; Kaji, Naoya; Suda, Kazunori; Kawakubo, Yoko; Suzuki, Mitsutoshi; Koyama, Tomozo; Kuno, Yusuke; Senzaki, Masao

Proceedings of INMM 51st Annual Meeting (CD-ROM), 10 Pages, 2010/07

Journal Articles

Technology development of K and N type multi-paired thermocouple for temperature measurement under neutron irradiation

Kitagishi, Shigeru; Inoue, Shuichi; Saito, Takashi; Omi, Masao; Tsuchiya, Kunihiko

UTNL-R-0475, p.2_5_1 - 2_5_9, 2010/03

no abstracts in English

JAEA Reports

Preliminary fabrication test of ceramic gas sensor for neutron irradiation tests

Kitagishi, Shigeru; Inoue, Shuichi; Saito, Takashi; Omi, Masao; Tsuchiya, Kunihiko

JAEA-Testing 2009-010, 14 Pages, 2010/02

JAEA-Testing-2009-010.pdf:6.12MB

It is important for neutron irradiation tests of materials and fuels to clarify the irradiation environment. Especially, the oxygen and hydrogen peroxide concentrations are required to measure for the analysis of corrosion mechanism of the structure materials in the light-Water Reactor (LWR) conditions. In this report, the trial fabrication tests of the ceramic gas sensor were carried out by the Spark Plasma Sintering (SPS) method and basic performance results of the sensor were described.

Journal Articles

Nuclear nonproliferation technology development program for future nuclear energy systems in Japan

Senzaki, Masao; Inoue, Naoko; Kuno, Yusuke; Namba, Takashi

Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.2128 - 2132, 2009/09

The development program of the FR cycle system incorporating nuclear nonproliferation technologies has been conducted in Japan mainly by the Japan Atomic Energy Agency (JAEA). Four areas which are critical in acquiring international acceptance are identified. They are (1) technology that enhances proliferation resistance, (2) advanced safeguards technology, (3) development of proliferation resistance evaluation methodology, and (4) nuclear security and physical protection technology. In each area, close communication between the nuclear energy system and process designers and experts on nuclear nonproliferation safeguards and proliferation resistance is critical for the developed system to be recognized to be proliferation resistant and robust against proliferation threats.

Journal Articles

Nuclear proliferation-resistance and safeguards for future nuclear fuel cycle

Kuno, Yusuke; Inoue, Naoko; Senzaki, Masao

Journal of Nuclear Materials, 385(1), p.153 - 156, 2009/03

 Times Cited Count:3 Percentile:26.15(Materials Science, Multidisciplinary)

Corresponding to the world nuclear security concerns, future nuclear fuel cycle (NFC) should have high proliferation-resistance (PR) and Physical Protection (PP), while promotion of the peaceful use of the nuclear energy must not be inhibited. In order to accomplish nuclear non-proliferation from NFC, a few models of the PR systems should be developed so that international community can recognize them as worldwide norms. To find a good balance of safeguard-ability (so-called extrinsic measure or institutional barrier) and impede-ability (intrinsic feature or technical barrier) will come to be essential for NFC designers to optimize civilian nuclear technology with nuclear non-proliferation, although the advanced Safeguards with high detectability can still play a dominant role for PR in the states complying with full institutional controls. Accomplishment of such norms in a good economic efficiency is a future key challenge.

Journal Articles

Advanced safeguards and proliferation resistance of the future nuclear fuel cycle systems

Kuno, Yusuke; Inoue, Naoko; Senzaki, Masao

Proceedings of INMM 50th Annual Meeting (CD-ROM), 10 Pages, 2009/00

International Safeguards including the Comprehensive Safeguards Agreement and the Additional Protocol is the most effective extrinsic measures. To find a good balance of safeguard-ability (so-called extrinsic measure or institutional barrier) and impede-ability (intrinsic measure or technical barrier) will come to be essential for nuclear fuel cycle designers to optimize civilian nuclear technology in terms of nuclear non-proliferation, although it is of importance that PR measures should economically be viable. Japanese primary challenge in nonproliferation for future nuclear fuel cycle is to accomplish robust Safeguards system to meet Safeguards criteria.

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