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Journal Articles

Evaluation of gamma-ray strength function based on measured gamma-ray pulse-height spectra in time-of-flight neutron capture experiments

Iwamoto, Nobuyuki; Nakamura, Shoji; Kimura, Atsushi; Katabuchi, Tatsuya*; Rovira, G.*; Hara, Kaoru*; Iwamoto, Osamu

EPJ Web of Conferences, 239, p.17016_1 - 17016_4, 2020/09

Journal Articles

Research on activation assessment of a reactor structural materials for decommissioning, 2

Seki, Misaki; Ishikawa, Koji*; Sano, Tadafumi*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Hanakawa, Hiroki; Ide, Hiroshi; Tsuchiya, Kunihiko; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2019, P. 279, 2020/08

no abstracts in English

Journal Articles

Manipulation of saturation magnetization and perpendicular magnetic anisotropy in epitaxial Co$$_{x}$$Mn$$_{4-x}$$N films with ferrimagnetic compensation

Ito, Keita*; Yasutomi, Yoko*; Zhu, S.*; Nurmamat, M.*; Tahara, Masaki*; Toko, Kaoru*; Akiyama, Ryota*; Takeda, Yukiharu; Saito, Yuji; Oguchi, Tamio*; et al.

Physical Review B, 101(10), p.104401_1 - 104401_8, 2020/03

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

Journal Articles

Research on activation assessment of a reactor structural materials for decommissioning

Seki, Misaki; Ishikawa, Koji*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Hanakawa, Hiroki; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURNS Progress Report 2018, P. 257, 2019/08

no abstracts in English

Journal Articles

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71, p.9_1 - 9_10, 2019/01

 Times Cited Count:4 Percentile:29.28(Geosciences, Multidisciplinary)

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of $$<$$10 keV.

Journal Articles

Liquid-like thermal conduction in intercalated layered crystalline solids

Li, B.; Wang, H.*; Kawakita, Yukinobu; Zhang, Q.*; Feygenson, M.*; Yu, H. L.*; Wu, D.*; Ohara, Koji*; Kikuchi, Tatsuya*; Shibata, Kaoru; et al.

Nature Materials, 17(3), p.226 - 230, 2018/03

 Times Cited Count:45 Percentile:3.45(Chemistry, Physical)

Journal Articles

Neutron scattering study of yttrium iron garnet

Shamoto, Shinichi; Ito, Takashi; Onishi, Hiroaki; Yamauchi, Hiroki; Inamura, Yasuhiro; Matsuura, Masato*; Akatsu, Mitsuhiro*; Kodama, Katsuaki; Nakao, Akiko*; Moyoshi, Taketo*; et al.

Physical Review B, 97(5), p.054429_1 - 054429_9, 2018/02

 Times Cited Count:5 Percentile:44.54(Materials Science, Multidisciplinary)

Nuclear and magnetic structure and full magnon dispersions of yttrium iron garnet Y$$_3$$Fe$$_5$$O$$_{12}$$ have been studied by neutron scattering. The lowest-energy dispersion below 14 meV exhibits a quadratic dispersion as expected from ferromagnetic magnons. The imaginary part of $$q$$-integrated dynamical spin susceptibility $$chi$$"($$E$$) exhibits a square-root energy-dependence in the low energies. The magnon density of state is estimated from the $$chi$$"($$E$$) obtained on an absolute scale. The value is consistent with a single chirality mode for the magnon branch expected theoretically.

JAEA Reports

Mizunami Underground Research Laboratory Project annual report for fiscal year 2016

Ishibashi, Masayuki; Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Takeuchi, Ryuji; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Iyatomi, Yosuke; et al.

JAEA-Review 2017-026, 72 Pages, 2018/01

JAEA-Review-2017-026.pdf:18.23MB

The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami, Gifu Prefecture, central Japan. On the occasion of the research program and management system revision of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). The R&D on three important issues have been carrying out on the MIU project. In this report, the current status of R&D activities and construction in 2016 is summarized.

Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Current R&D status of thermochemical water splitting iodine-sulfur process in Japan Atomic Energy Agency

Kasahara, Seiji; Iwatsuki, Jin; Takegami, Hiroaki; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Onuki, Kaoru; Kubo, Shinji

International Journal of Hydrogen Energy, 42(19), p.13477 - 13485, 2017/05

 Times Cited Count:23 Percentile:19.04(Chemistry, Physical)

Current R&D on the thermochemical water splitting iodine-sulfur (IS) process in Japan Atomic Energy Agency is summarized. Reactors were fabricated with industrial materials and verified by test operations: a Bunsen reactor, a H$$_{2}$$SO$$_{2}$$ decomposer, and a HI decomposer. Reactors of industrial materials showed corrosion stability. Demonstration of the test facility verified integrity of process components and stability of hydrogen production. An 8 hours continuous operation of the total IS process was performed in February 2016 with H$$_{2}$$ production rate of 10 L/h.

JAEA Reports

Mizunami Underground Research Laboratory Project annual report for fiscal year 2015

Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Mikake, Shinichiro; Ishibashi, Masayuki; Onoe, Hironori; Takeuchi, Ryuji; Nohara, Tsuyoshi; Sasao, Eiji; Ikeda, Koki; et al.

JAEA-Review 2016-023, 65 Pages, 2016/12

JAEA-Review-2016-023.pdf:47.32MB

The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami City in Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modelling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). These R&D on three important issues have been carrying out on the MIU project. In this report, the current status of R&D activities and construction in 2015 is summarized.

Journal Articles

Verification of a quantitative method of uranium 238 in the radioactive waste using photon occurred by Compton effect

Yokoyama, Kaoru; Hata, Haruhi; Naganuma, Masaki; Ohara, Yoshiyuki; Ishimori, Yuu

Radioisotopes, 64(11), p.687 - 696, 2015/11

Authors developed the new analysis technique (hereinafter referred to as the equivalent model) which calculates the amount of uranium by correcting the influence of uneven distribution of the uranium. Two $$gamma$$ rays different in the shelter effect are used in the equivalent model. The $$gamma$$ rays (766 keV, 1001 keV ) released from $$^{rm 234m}$$Pa are used for uranium quantitative determination. The quantity error is decided by the $$gamma$$ ray with the small calculation rate. The way to get the high calculation rate is considered to reduce the quantity error. Many $$gamma$$ rays are scattered by the Compton effect in radioactive waste, and scattered photons occur. We applied the scattered photon with the big count rate to equivalent model. It was effective to apply the count rate of the scattered photon by the Compton effect to equivalent model.

JAEA Reports

Research and development on chemical reactors made of industrial structural materials and hydriodic acid concentration technique for thermochemical hydrogen production IS process

Kubo, Shinji; Iwatsuki, Jin; Takegami, Hiroaki; Kasahara, Seiji; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Onuki, Kaoru

JAEA-Technology 2015-028, 32 Pages, 2015/10

JAEA-Technology-2015-028.pdf:23.69MB

JAEA has been conducting a study on IS process for thermochemical hydrogen production in order to develop massive hydrogen production technology for hydrogen society. Integrity of the chemical reactors and concentration technology of hydrogen iodide in HIx solution were studied. In the former study, the chemical reactors were trial-fabricated using industrial materials. A test of 30 times of thermal cycle test under circulating condition of the Bunsen reaction solution showed integrity of the Bunsen reactor made of fluororesin lined steel. Also, 100 hours of reaction tests showed integrity of the sulfuric acid decomposer made of silicon carbide and of the hydrogen iodide decomposer made of Hastelloy C-276. In the latter study, concerning electro-electrodialysis using cation-exchange membrane, sulfuric acid in the anolyte had little influence on the concentration performance. These results suggest the purification system of HIx solution can be simplified. Based on the Nernst-Planck equation and the Smoluchowski equation, proton transport number, water permeance, and IR drop of the cation exchange membrane were formulated. The derived equations enable quantitative estimation for the performance indexes of Nafion membrane and, also, of ETFE-St membranes made by radiation-induced graft polymerization method.

Journal Articles

Application of support vector machine to rapid classification of uranium waste drums using low-resolution $$gamma$$-ray spectra

Hata, Haruhi; Yokoyama, Kaoru; Ishimori, Yuu; Ohara, Yoshiyuki; Tanaka, Yoshio; Sugitsue, Noritake

Applied Radiation and Isotopes, 104, p.143 - 146, 2015/10

 Times Cited Count:4 Percentile:53.24(Chemistry, Inorganic & Nuclear)

We investigated the feasibility of using support vector machine (SVM), a computer learning method, to classify uranium waste drums as natural uranium or reprocessed uranium based on their origins. The method was trained using 12 training datasets were used and tested on 955 datasets of $$gamma$$-ray spectra obtained with NaI(Tl) scintillation detectors. The results showed that only 4 out of 955 test datasets were different from the original labels-one of them was mislabeled and the other three were misclassified by SVM. These findings suggest that SVM is an effective method to classify a large quantity of data within a short period of time. Consequently, SVM is a feasible method for supporting the scaling factor method and as a supplemental tool to check original labels.

Journal Articles

Stabilization of a high-order harmonic generation seeded extreme ultraviolet free electron laser by time-synchronization control with electro-optic sampling

Tomizawa, Hiromitsu*; Sato, Takahiro*; Ogawa, Kanade*; Togawa, Kazuaki*; Tanaka, Takatsugu*; Hara, Toru*; Yabashi, Makina*; Tanaka, Hitoshi*; Ishikawa, Tetsuya*; Togashi, Tadashi*; et al.

High Power Laser Science and Engineering, 3, p.e14_1 - e14_10, 2015/04

 Times Cited Count:2 Percentile:81.74(Optics)

no abstracts in English

Journal Articles

Misassigned neutron resonances of $$^{142}$$Nd and stellar neutron capture cross sections

Katabuchi, Tatsuya*; Matsuhashi, Taihei*; Terada, Kazushi; Igashira, Masayuki*; Mizumoto, Motoharu*; Hirose, Kentaro; Kimura, Atsushi; Iwamoto, Nobuyuki; Hara, Kaoru*; Harada, Hideo; et al.

Physical Review C, 91(3), p.037603_1 - 037603_5, 2015/03

 Times Cited Count:4 Percentile:67.37(Physics, Nuclear)

Journal Articles

Response function for the measurement of (n,$$gamma$$) reactions with the ANNRI-Cluster Ge detectors at J-PARC

Hara, Kaoru; Goko, Shinji*; Harada, Hideo; Hirose, Kentaro; Kimura, Atsushi; Kin, Tadahiro*; Kitatani, Fumito; Koizumi, Mitsuo; Nakamura, Shoji; Toh, Yosuke; et al.

JAEA-Conf 2014-002, p.88 - 92, 2015/02

Journal Articles

Selector-valve failed fuel detection and location system for Japan Sodium-cooled Fast Reactor

Aizawa, Kosuke; Fujita, Kaoru; Kamide, Hideki; Kasahara, Naoto*

Nuclear Technology, 189(2), p.111 - 121, 2015/02

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Selector-valve mechanism is adopted in the design of JSFR for its failed-fuel detection and location (FFDL) system. JSFR has only two FFDL units for 562 core fuel subassemblies to reduce construction cost by decreasing the reactor vessel diameter. Consequently, one SV-FFDL unit must handle about 300 subassemblies. In addition, JSFR adopts an upper internal structure (UIS) with a slit above the core. Sampling performance for the subassemblies under the UIS slit has been evaluated to be lower than those under the normal UIS position in the previous water experiments and numerical simulation. In this paper, the outline of FFDL system is shown, which can be applied to so large number of fuel subassemblies in a compact reactor vessel. Detection capability of the FFDL system was studied to achieve the design conditions. Operation modes and procedure of the FFDL system also investigated.

Journal Articles

Current status of R&D activities and future plan and role of JAEA's two generic URLs

Koide, Kaoru; Osawa, Hideaki; Ito, Hiroaki; Tanai, Kenji; Semba, Takeshi; Naito, Morimasa; Sugihara, Kozo; Miyamoto, Yoichi

Annual Waste Management Symposium (WM 2015), Vol.5, p.3631 - 3645, 2015/00

JAEA has promoted R&D on HLW geological disposal technology. JAEA launched the Mizunami and the Horonobe URL Projects to cover the diversity of geological environments in Japan. The Mizunami URL Project is a geoscientific research project in the crystalline rock environment. The Horonobe URL Project consists of geoscientific studies and R&D on geological disposal technology in the sedimentary rock environment. Both URL projects have been planned to proceed in three overlapping phases, Surface-based investigation Phase, Construction Phase and Operation Phase. Currently, the construction of research galleries in both of the Mizunami and the Horonobe URLs has been completed to 500 m and 350 m depths, respectively. JAEA will promote R&D activities in Phase III including study of the long-term evolution of the geological environment, and contribute to international cooperation, development of human resources and communication amongst stakeholders through both URL projects.

JAEA Reports

Mizunami Underground Research Laboratory Project annual report for fiscal year 2013

Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Kawamoto, Koji; Yamada, Nobuto; Ishibashi, Masayuki; Murakami, Hiroaki; Matsuoka, Toshiyuki; Sasao, Eiji; Sanada, Hiroyuki; et al.

JAEA-Review 2014-038, 137 Pages, 2014/12

JAEA-Review-2014-038.pdf:162.61MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in fiscal year 2013. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2013, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.

259 (Records 1-20 displayed on this page)