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Journal Articles

IAEA support for nuclear facilities in Ukraine during Russia's invasion

Kobayashi, Naoki

Dai-44-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 5 Pages, 2023/11

no abstracts in English

JAEA Reports

Physical property investigation of gloves for glove boxes in nuclear fuel reprocessing plants; Physical properties of used gloves and estimation of its life-time

Yamamoto, Masahiko; Nishida, Naoki; Kobayashi, Daisuke; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kitao, Takahiko; Kuno, Takehiko

JAEA-Technology 2023-004, 30 Pages, 2023/06

JAEA-Technology-2023-004.pdf:1.94MB

Glove-box gloves, that are used for handling nuclear fuel materials at the Tokai Reprocessing Plant (TRP) of the Japan Atomic Energy Agency, have an expiration date by internal rules. All gloves are replaced at a maximum of every 4-year. However, degrees of glove deterioration varies depending on its usage environment such as frequency, chemicals, and radiation dose. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured and technical evaluation method for the glove life-time is established. It was found that gloves without any defects in its appearance have enough physical properties and satisfies the acceptance criteria values of new gloves. Thus, it was considered that the expired gloves could be used for total of 8-year, by adding 4-year of new glove life-time. In addition, the results of extrapolation by plotting the glove's physical properties versus the used years showed that the physical properties at 8-year is on the safer side than the reported physical properties of broken glove. Also, the data are not significantly different from the physical properties of the long-term storage glove (8 and 23 years). Based on these results, life-time of gloves at TRP is set to be 8-year. The frequency of glove inspections are not changed, and if any defects is found, the glove is promptly replaced. Thus, the risk related to glove usage is not increased. The cost of purchasing gloves, labor for glove replacement, and the amount of generated waste can be reduced by approximately 40%, respectively, resulting in more efficient and rationalized glove management.

Journal Articles

Investigation of physical properties of glove for glove-box and estimation of its life-time

Kobayashi, Daisuke; Yamamoto, Masahiko; Nishida, Naoki; Miyoshi, Ryuta; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kato, Keisuke; Nishino, Saki; Kuno, Takehiko; Kitao, Takahiko; et al.

Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.237 - 240, 2022/07

All gloves attached to glove-box in Tokai Reprocessing Plant have a fixed expiration date and have to be replaced every 4-year. However, degrees of glove deterioration are different depending on its usage environment (frequency, chemicals, radiation, etc.), because of rubber products. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured, and the life-time of gloves are estimated. As a result, gloves without any defects in its appearance have enough physical property for acceptance criteria of new glove. The extrapolated physical property of glove is sufficiently larger than the reported values of damaged glove. No deterioration in physical properties of gloves, that are periodically replaced without any defects in its appearance, is observed and the usable life-time of the glove is estimated to be 8 years.

Journal Articles

Age-hardening mechanisms of heterogeneous-nanostructured SUS316LN stainless steel fabricated by heavy cold rolling

Miura, Hiromi*; Watanabe, Chihiro*; Aoyagi, Yoshiteru*; Oba, Yojiro; Kobayashi, Masakazu*; Yoshinaga, Naoki*

Materials Science & Engineering A, 833, p.142531_1 - 142531_12, 2022/01

 Times Cited Count:3 Percentile:48.15(Nanoscience & Nanotechnology)

Journal Articles

Autoradiography system with phosphor powder (ZnS:Ag) for imaging radioisotope dynamics in a living plant

Kurita, Keisuke; Sakai, Takuro; Suzui, Nobuo*; Yin, Y.-G.*; Sugita, Ryohei*; Kobayashi, Natsuko*; Tanoi, Keitaro*; Kawachi, Naoki*

Japanese Journal of Applied Physics, 60(11), p.116501_1 - 116501_4, 2021/11

 Times Cited Count:1 Percentile:8.23(Physics, Applied)

Radioisotope tracer imaging is useful for studying plant physiological phenomena. In this study, we developed an autoradiography system with phosphor powder (ZnS:Ag), "Live-autoradiography", for imaging radioisotope dynamics in a living plant. This system visualizes the element migration and accumulation in intact plants continuously under a light environment. An imaging test was performed on point sources of $$^{137}$$Cs, with a radioactivity of 10-100 kBq of being observed; this indicates satisfactory system linearity between the image intensity and the radioactivity of $$^{137}$$Cs. Moreover, dynamics imaging of $$^{137}$$Cs was performed on an intact soybean plant for four days. The serial images indicated $$^{137}$$Cs accumulation in the node, vein, and growing point of the plant. The developed system can be used for studying plant physiological phenomena and can be employed for quantitative measurement of radionuclides.

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:14 Percentile:74.77(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

Upgrade and Replacement of Plant Dynamics Test Loop (PLANDTL)

Uchiyama, Naoki*; Ozawa, Tatsuya*; Sato, Koji*; Kobayashi, Jun; Onojima, Takamitsu; Tanaka, Masaaki

FAPIG, (194), p.12 - 18, 2018/02

no abstracts in English

Journal Articles

Vibrational states of atomic hydrogen in bulk and nanocrystalline palladium studied by neutron spectroscopy

Kofu, Maiko; Hashimoto, Naoki*; Akiba, Hiroshi*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; Iida, Kazuki*; Nakamura, Mitsutaka; Yamamuro, Osamu*

Physical Review B, 96(5), p.054304_1 - 054304_7, 2017/08

 Times Cited Count:12 Percentile:58.67(Materials Science, Multidisciplinary)

The vibrational states of hydrogen atoms in bulk and nanocrystalline palladium were examined in a wide energy region $$0 le hbar omega le 300$$ meV using neutron spectroscopy. In bulk PdH$$_{0.73}$$, the vibrational excitations of H atoms were roughly reproduced by the quantum harmonic oscillator (QHO) model. In PdH$$_{0.42}$$ nanocrystals with a diameter of 8 nm, however, additional vibrational excitations were found at energies above 80 meV. The energies and intensities of the additional states were not explained by QHO but reasonably described as vibrations in a highly anharmonic trumpet-like potential. The additional excitations are attributed to the vibrations of H atoms at tetrahedral sites in the subsurface region stabilized by surface effects. This is an experimental work which clearly detects hydrogen vibration ${it inside}$ metal nanoparticles.

Journal Articles

Good practices in provision of nuclear security training courses at the integrated support center for nuclear nonproliferation and nuclear security

Naoi, Yosuke; Noro, Naoko; Kobayashi, Naoki; Robertson, K.

Proceedings of INMM 58th Annual Meeting (Internet), 10 Pages, 2017/07

More than six years have passed since the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) was established under the Japan Atomic Energy Agency (JAEA) in December 2010 and started its activities, in response to the commitment of Japan at the Nuclear Security Summit in Washington D.C.. ISCN has been vigorously involved in the capacity building assistance on nuclear nonproliferation (safeguards) and nuclear security, mainly in the Asian region. It has provided 120 training courses with 3,257 participants in total up to January 2017. ISCN has been playing a major role in strengthening nuclear nonproliferation and nuclear security in this region, and this can be considered as one of the great results of the Nuclear Security Summit process. Particularly, ISCN's nuclear security training courses, primarily two-week course on physical protection of nuclear material and nuclear facilities, have been building up its own instructors in cooperation with the U.S. Department of Energy/National Nuclear Security Administration and Sandia National Laboratories. It has also been providing the courses with emphasis on universalization of the IAEA INFCIRC/225/Rev.5 and nuclear security culture. Furthermore, ISCN has provided the training courses for the experts in Japan making the best use of our knowledge and experience of organizing international training courses. The total number of the Japanese experts participating in ISCN courses reached to more than 1200. In addition to that ISCN conducted a special lecture on nuclear security culture at the thirteen-nuclear power plant (NPP) sites in Japan, and three thousand workers at NPPs joined the lecture. This shows that the ISCN has been recognized as an expert organization of nuclear security training support in Japan. This paper will describe the good practices at ISCN through six years activities mainly the progress in our nuclear security training.

Journal Articles

Development of human resource capacity building assistance for nuclear security

Noro, Naoko; Nakamura, Yo; Hirai, Mizuki; Kobayashi, Naoki; Kawata, Norio; Naoi, Yosuke

Modern Environmental Science and Engineering, 3(5), p.309 - 313, 2017/05

The paper introduces methodologies of ISCN for nuclear security training curricula development. The paper focuses on the contribution of ISCN for curriculum development of IAEA transport security training course which ISCN hosted in 2015.

Journal Articles

Research on vitrification technology to immobilize radioactive sludge generated from Fukushima Daiichi Power Plant; Enhanced glass medium

Amamoto, Ippei; Kobayashi, Hidekazu; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*; Fukayama, Daigen*; Nagano, Yuichi*; Jantzen, T.*; Hack, K.*

Journal of Nuclear Science and Technology, 53(10), p.1467 - 1475, 2016/10

 Times Cited Count:2 Percentile:28.38(Nuclear Science & Technology)

The iron phosphate glass (IPG) medium is known to be a high-efficiency glass medium, therefore we try to evaluate its applicability to immobilize sludge bearing radioactive nuclides arising from treatment of contaminated water at the stricken Fukushima Daiichi Nuclear Power Plant. For this study, many physical and chemical properties of target materials are necessary to evaluate the behaviours of IPG medium and its waste forms. Inevitably, it will entail the need for many and varied types of experiments to be carried out under high temperature. It is therefore rational to apply appropriate theoretical analysis first so as to reduce the number of experimental run. For this reason, some necessary thermodynamic values for theoretical analysis were estimated by CALPHAD approach followed by making up the calculated phase diagrams. By comparison with experimental results, they were found to be reliable for evaluating the behaviours of IPG medium and its waste forms.

Journal Articles

Development of human resource capacity building assistance for nuclear security

Noro, Naoko; Nakamura, Yo; Hirai, Mizuki; Kobayashi, Naoki; Kawata, Norio; Naoi, Yosuke

Proceedings of 18th International Symposium on the Packaging and Transport of Radioactive Materials (PATRAM 2016) (DVD-ROM), 7 Pages, 2016/09

The paper describes the methdologies ISCN has adopted to develop its training curricula on nuclear security. ISCN has been working closely with the international partners to build its own capacity, especially with the Sandia National Laboratories of the United States. The paper then focuses on the joint course development between IAEA and ISCN on the International Training Course on Transport Security which ISCN hosted in 2015.

Journal Articles

Effect of magnetism on lattice dynamics in SrFe$$_2$$As$$_2$$ using high-resolution inelastic X-ray scattering

Murai, Naoki*; Fukuda, Tatsuo; Kobayashi, Tatsuya*; Nakajima, Masamichi*; Uchiyama, Hiroshi*; Ishikawa, Daisuke*; Tsutsui, Satoshi*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.

Physical Review B, 93(2), p.020301_1 - 020301_5, 2016/01

 Times Cited Count:7 Percentile:34.33(Materials Science, Multidisciplinary)

Journal Articles

2016 Professional Engineer (PE) test preparation course "Nuclear and Radiation Technical Disciplines"

Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.

Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00

no abstracts in English

JAEA Reports

Report of "The 2014 International Forum on Peaceful Use of Nuclear Energy, Nuclear Non-proliferation and Nuclear Security; Future direction toward promoting non-proliferation and the ideal method of developing human resources using Centers of Excellence(COEs) following the New Strategic Energy Plan"

Yamaga, Chikanobu; Tomikawa, Hirofumi; Kobayashi, Naoki; Naoi, Yosuke; Oda, Tetsuzo; Mochiji, Toshiro

JAEA-Review 2015-023, 108 Pages, 2015/10

JAEA-Review-2015-023.pdf:15.22MB

The JAEA held "International Forum on Peaceful Use of Nuclear Energy, Nuclear Non-proliferation and Nuclear Security -Future direction toward promoting non-proliferation and the ideal method of developing human resources using COEs following the New Strategic Energy Plan -" on 3 December 2014. In the Forum, officials and experts from Japan, the United States explained their efforts. Discussion was made in two panels, entitled "Effective and efficient measures to ensure nuclear non-proliferation based on domestic and foreign issues and the direction and role of technology development" and "Roles of nuclear security COEs and future expectations". In Panel Discussion 1, how to implement effective and efficient safeguards was discussed. In Panel Discussion 2, panelists discussed current status of NSSCs and COEs, new role for COEs and regional cooperation. This report includes abstracts of keynote speeches, summaries of two panel discussions and materials of the presentations in the forum.

Journal Articles

Overview of activities and outcomes at ISCN related to Japanese commitment at nuclear security summit process

Naoi, Yosuke; Kobayashi, Naoki; Mochiji, Toshiro; Senzaki, Masao; Seya, Michio

Proceedings of 37th ESARDA Annual Meeting (Internet), p.100 - 110, 2015/08

In April 2010 at the Nuclear Security Summit in Washington, D.C., Japan made a commitment to establish a center of excellence on nuclear nonproliferation and security. This center would support capacity building for strengthening nuclear nonproliferation and security mainly in the Asian region and also would engage in development of technology related measurement and detection of nuclear material including nuclear forensics based on international cooperation. According to this statement, Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) was established under Japan Atomic Energy Agency (JAEA) in December 2010. Since its establishment four years ago, ISCN has developed its activities, having already conducted 74 training courses for the nuclear nonproliferation and security fields and having trained 2,096 participants from 49 countries (including Japan) and three international organizations. As for technical development on detection and measurement of nuclear material, ISCN has carried out substantial outcome with the international cooperation of U.S. and EU/JRC. It can be said that it is a significant achievement of the Nuclear Security Summit process. This paper will overview the outcome of ISCN's activities over the past four years.

Journal Articles

JAEA-ISCN development programs of advanced NDA technologies of nuclear material

Seya, Michio; Kobayashi, Naoki; Naoi, Yosuke; Hajima, Ryoichi; Soyama, Kazuhiko; Kureta, Masatoshi; Nakamura, Hironobu; Harada, Hideo

Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03

JAEA-ISCN has been implementing basic development programs of the advanced NDA technologies for nuclear material (NM) since 2011JFY (Japanese Fiscal Year), which are (1) NRF (Nuclear resonance fluorescence) NDA technology using laser Compton scattered (LCS) $$gamma$$-rays (intense mono-energetic $$gamma$$-rays), (2) Alternative to $$^{3}$$He neutron detection technology using ZnS/B$$_{2}$$O$$_{3}$$ ceramic scintillator, and (3) NRD (Neutron resonance densitometry) using NRTA (Neutron resonance transmission analysis) and NRCA (Neutron resonance capture analysis). These programs are going to be finished in 2014JFY and have demonstration tests in February - March 2015.

Journal Articles

Basic technology development of advanced non-destructive detection / Measurement of nuclear material for nuclear security and nuclear nonproliferation

Seya, Michio; Naoi, Yosuke; Kobayashi, Naoki; Nakamura, Takahisa; Hajima, Ryoichi; Soyama, Kazuhiko; Kureta, Masatoshi; Nakamura, Hironobu; Harada, Hideo

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/01

The Integrated Support Center for Nuclear Non-proliferation and Nuclear Security (ISCN) of Japan Atomic Energy Agency (JAEA) has been conducting (based on collaborations with JAEA other centers) the following basic technology development programs of advanced non-destructive detection/measurement of nuclear material for nuclear security and nuclear non-proliferation. (1) The demonstration test of the Pu-NDA system for spent fuel assembly using PNAR and SINRD (JAEA/USDOE(LANL) collaboration, completed in JFY2013), (2) Basic development of NDA technologies using laser Compton scattered $$gamma$$-rays (Demonstration of an intense mono-energetic $$gamma$$-ray source), (3) Development of alternative to He-3 neutron detection technology, (4) Development of neutron resonance densitometry (JAEA/JRC collaboration)This paper introduces above programs.

Journal Articles

Activities at the integrated support center for nuclear nonproliferation and nuclear security, and trilateral harmonization among Japan, ROK, and China

Naoi, Yosuke; Kobayashi, Naoki; Senzaki, Masao

Proceedings of INMM 55th Annual Meeting (Internet), 9 Pages, 2014/07

Within the Asian region, China and ROK also committed at the 2010 Security Summit to establishing similar training centers. ROK established one in February 2014, and China started construction on its center in October 2013, aiming to commence activities in 2015. In 2013, the International Atomic Energy Agency (IAEA) started discussions with these three countries for the harmonization of the contents of their centers' training activities. The purpose of these discussions is to avoid duplication of effort, since three centers of a similar kind will be established in the Asian region. In these discussions, ISCN has taken the lead to find ways to make this harmonization a reality. This paper will present the result of ISCN's activities over the past three and a half years; the current situation of the cooperation among the three countries, Japan, China, and ROK; and the future efforts to be made.

Journal Articles

Observation of a $$p$$-wave one-neutron halo configuration on $$^{37}$$Mg

Kobayashi, Nobuyuki*; Nakamura, Takashi*; Kondo, Yosuke*; Tostevin, J. A.*; Utsuno, Yutaka; Aoi, Nori*; Baba, Hidetada*; Barthelemy, R.*; Famiano, M. A.*; Fukuda, Naoki*; et al.

Physical Review Letters, 112(24), p.242501_1 - 242501_5, 2014/06

 Times Cited Count:83 Percentile:94.33(Physics, Multidisciplinary)

no abstracts in English

93 (Records 1-20 displayed on this page)