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Journal Articles

The Energy-resolved neutron imaging system, RADEN

Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Nakatani, Takeshi; Segawa, Mariko; Hiroi, Kosuke; Su, Y. H.; Oi, Motoki; Harada, Masahide; Iikura, Hiroshi; et al.

Review of Scientific Instruments, 91(4), p.043302_1 - 043302_20, 2020/04

 Times Cited Count:42 Percentile:96.38(Instruments & Instrumentation)

Journal Articles

Simulation study of the effects of buildings, trees and paved surfaces on ambient dose equivalent rates outdoors at three suburban sites near Fukushima Dai-ichi

Kim, M.; Malins, A.; Yoshimura, Kazuya; Sakuma, Kazuyuki; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko; Hasegawa, Yukihiro*; Yanagi, Hideaki*

Journal of Environmental Radioactivity, 210, p.105803_1 - 105803_10, 2019/12

 Times Cited Count:4 Percentile:17.11(Environmental Sciences)

To improve the accuracy of simulations for air dose rates over fallout contaminated areas, the distribution of the radionuclides within the environment should be modelled realistically, e.g. considering differences in radioactivity levels between agricultural land, urban surfaces, and forest compartments. Moreover simulations should model the shielding of $$gamma$$ rays by buildings, trees and land topography. Here we outline a system for generating three dimensional models of urban and rural areas in Fukushima Prefecture. The $$^{134}$$Cs and $$^{137}$$Cs radioactivity distribution can be set flexibly across the different components of the model. The models incorporate realistic representations of local buildings, based on nine common Japanese designs, individual conifer and broadleaf trees, and the topography of the land surface. Models are generated from Digital Elevation Model (DEM) and Digital Surface Model (DSM) datasets, and refined by users assisted with ortho-photographs of target sites. Completed models are exported from the system in a format suitable for the Particle and Heavy Ion Transport code System (PHITS) for the calculation of air dose rates and other radiological quantities. The system is demonstrated by modelling a suburban area 4 km from the Fukushima Daiichi Nuclear Power Plant that has yet to be decontaminated. Air dose rates calculated in PHITS were correlated with measurements taken across the site in a car-borne survey.

Journal Articles

Measurements of capture $$gamma$$ rays from the neutron resonances of $$^{74}$$Se and $$^{77}$$Se at the J-PARC/MLF/ANNRI

Hori, Junichi*; Yashima, Hiroshi*; Nakamura, Shoji; Furutaka, Kazuyoshi; Hara, Kaoru; Harada, Hideo; Hirose, Kentaro; Kimura, Atsushi; Kitatani, Fumito; Koizumi, Mitsuo; et al.

Nuclear Data Sheets, 119, p.128 - 131, 2014/05

 Times Cited Count:4 Percentile:33.13(Physics, Nuclear)

In this work, we measured the capture $$gamma$$ rays from the neutron resonances of $$^{74}$$Se and $$^{77}$$Se. A neutron time-of-flight method was adopted for the measurements with a 4$$pi$$ Ge spectrometer installed at the Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) in the J-PARC Material and Life science experimental Facility (MLF). The $$gamma$$-ray pulse-height spectra corresponding to the 27-eV resonance of $$^{74}$$Se and the 113-, 212-, 291-, 342-, 690- and 864-eV resonances of $$^{77}$$Se were obtained by gating on the TOF regions, respectively. The relative intensities of those primary transitions were derived and compared with the previous experimental data. For the 27-eV resonance of $$^{74}$$Se, a strong primary transition to the 293-keV state was observed. As for $$^{77}$$Se, the quite differences of the decay pattern were found between the resonances.

JAEA Reports

Safety demonstration test using the High Temperature Engineering Test Reactor (HTTR); Cold test of the loss of forced cooling

Shinohara, Masanori; Yanagi, Shunki; Tochio, Daisuke; Shimazaki, Yosuke; Nojiri, Naoki; Owada, Hiroyuki; Sato, Nao; Sagawa, Hiroshi; Umeda, Masayuki

JAEA-Technology 2011-029, 39 Pages, 2011/12

JAEA-Technology-2011-029.pdf:3.03MB

JAEA plans and performs the safety demonstration test using the HTTR to develop High Temperature Gas Reactor technologies. Cold test of the loss of forced cooling was conducted prior to the safety demonstration test, to check test procedure and plant behavior. Cold test consists of two phases, Phase1, 1 or 2 Vessel Cooling System (VCS) terminates, in the Phase2, all 3 Gas circulators and 1 VCS terminates. Cold test could confirm test process, and obtain data necessary to analysis and 2-dimensional horizontal sectional model analysis was verified to simulate actual measurement value.

Journal Articles

Multi-layered parallel plate ionization chamber for cross-section measurements of minor actinides

Hirose, Kentaro*; Otsuki, Tsutomu*; Shibasaki, Yoshinobu*; Iwasa, Naohito*; Hori, Junichi*; Takamiya, Koichi*; Yashima, Hiroshi*; Nishio, Katsuhisa; Kiyanagi, Yoshiaki*

Nuclear Instruments and Methods in Physics Research A, 621(1-3), p.379 - 382, 2010/09

 Times Cited Count:3 Percentile:28.87(Instruments & Instrumentation)

Journal Articles

Design of the pulse bending magnet for switching the painting area between the MLF and MR in J-PARC 3-GeV RCS

Takayanagi, Tomohiro; Yoshimoto, Masahiro; Watanabe, Masao; Saha, P. K.; Ueno, Tomoaki; Togashi, Tomohito; Yamazaki, Yoshio; Kinsho, Michikazu; Fujimori, Hiroshi*; Irie, Yoshiro*

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3293 - 3295, 2010/05

It has been designed the pulse bending magnet for switching the painting area to the MLF and MR, which is located in injection line area in J-PARC 3-GeV RCS. After upgrading the linac energy to 400 MeV, the two pulse magnets switch the injection beam orbit to change the each painting area by each shot of 25 Hz. The magnetic field strength switching by 25 Hz are required for the painting injection. Furthermore, in the case of the beam commissioning of the 3-GeV RCS, the center injection is performed. Therefore, the wide range of the beam bending angle from 3 mrad to 38 mrad is required for the pulse magnets.

Journal Articles

Antiferromagnetic bipolar semiconductor LaMnPO with ZrCuSiAs-type structure

Yanagi, Hiroshi*; Watanabe, Takumi*; Kodama, Katsuaki; Iikubo, Satoshi*; Shamoto, Shinichi; Kamiya, Toshio*; Hirano, Masahiro*; Hosono, Hideo*

Journal of Applied Physics, 105(9), p.093916_1 - 093916_8, 2009/05

 Times Cited Count:47 Percentile:83.41(Physics, Applied)

Electronic and magnetic properties of a layered compound LaMnPO are examined in relation to a newly discovered iso-structural superconductor LaFeAs(P)O. Neutron diffraction measurements, together with temperature dependent magnetic susceptibility, clarify that LaMnPO is an antiferromagnet at least up to 375 K. The spin moment of a Mn ion is determined to be 2.26 $$mu_{B}$$ at room temperature, and the spin configuration is antiparallel in the Mn-P plane and parallel to between the Mn-P planes, which is rather different from that of LaFeAsO. Optical absorption spectra, photoemission spectra, and temperature dependent electrical conductivity indicate that LaMnPO is a semiconductor. Furthermore, nominally undoped LaMnPO exhibits $$n$$-type conduction while the conduction type is changed by doping of Cu or Ca to the La sites, indicating that LaMnPO is a bipolar conductor. Density functional calculation using the GGA+U approximation supports the above conclusions; the electronic band structure has an open band gap and the antiferromagnetic spin configuration is more stable than the ferromagnetic one.

Journal Articles

New JMTR irradiation test plan on fuels and materials

Nakamura, Takehiko; Nishiyama, Yutaka; Chimi, Yasuhiro; Sasajima, Hideo; Ogiyanagi, Jin; Nakamura, Jinichi; Suzuki, Masahide; Kawamura, Hiroshi

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

In order to maintain and enhance safety of light water reactors in long-term and up-graded operations, proper understanding of irradiation behavior of fuels and materials is essentially important. Japanese government and the Japan Atomic Energy Agency have decided to refurbish the JMTR and to install new tests rigs, in order to play an active role for solving irradiation related issues on plant aging and high-duty uses of the current LWRs and on development of next-generation reactors. New tests on fuel integrity under simulated abnormal transients and high-duty irradiation conditions are planned in the JMTR. Power ramp tests of new design fuel rods will also be performed in the first stage of the program, which is expected to start in year 2011 after refurbishment of the JMTR. Combination of the JMTR tests with simulated reactivity initiated accident tests in the NSRR and loss of coolant accident tests in hot laboratories would serve as the integrated fuel safety research on the high performance fuels at extended burnups, covering from the normal to the accident conditions, including abnormal transients. For the materials irradiation, fracture toughness of reactor vessel steels and stress corrosion cracking behavior of stainless steels are being studied in addition to basic irradiation behavior of nuclear materials such as hafnium. The irradiation studies would contribute not only to solve the current problems but also to identify possible seeds of troubles and to make proactive responses.

Journal Articles

Design and construction of septum magnets at 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Ueno, Tomoaki; Togashi, Tomohito; Takeda, Osamu; Kanazawa, Kenichiro; Watanabe, Masao; Yamazaki, Yoshio; Kamiya, Junichiro; Takayanagi, Tomohiro; Kuramochi, Masaya; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.297 - 300, 2008/06

 Times Cited Count:4 Percentile:30.92(Engineering, Electrical & Electronic)

Journal Articles

Impression on attending The 20th Anniversary International Symposium in Honor of J.G. Bednorz and K.A. Muller

Arai, Masatoshi; Ando, Yoichi*; Oyanagi, Hiroyuki*; Kamimura, Hiroshi*; Takashige, Masaaki*; Maeno, Yoshiteru*

Kotai Butsuri, 41(8), p.529 - 539, 2006/08

no abstracts in English

Journal Articles

Design of thick septa magnets based on 3D field calculation for the 3 GeV rapid cycling synchrotron of J-PARC

Watanabe, Masao; Irie, Yoshiro; Kamiya, Junichiro; Shimada, Taihei; Takayanagi, Tomohiro; Fujimori, Hiroshi*; Igarashi, Susumu*; Kawakubo, Toshimichi*; Nakayama, Hisayoshi*

IEEE Transactions on Applied Superconductivity, 16(2), p.1350 - 1353, 2006/06

 Times Cited Count:2 Percentile:18.9(Engineering, Electrical & Electronic)

Thick septa are used in the injection and extraction section of the 3 GeV rapid cycling synchrotron of the J-PARC. We have been designing seven thick septum magnets, two for injection, two for beam dump and three for extraction, respectively. These septa require low-loss operations. For the mechanical stability they are operated by direct current. The yoke is made of the soft-iron block. We have been designing them by using the three-dimensional magnet static field calculation code, TOSCA. In this presentation, we discuss about magnetic field flatness in the gap and effects of the leakage fields in the synchrotron.

Journal Articles

Study of long-term behavior of engineered and geological barrier system

Aoyanagi, Shigeo; Oda, Yoshihiro; Sasamoto, Hiroshi; Shibata, Masahiro; Tanai, Kenji; Taniguchi, Naoki; Nishimura, Mayuka; Fujisaki, Kiyoshi; Kikuchi, Hirohito*; Matsumoto, Kazuhiro*

Hoshasei Haikibutsu Anzen Kenkyu Nenji Keikaku (Heisei-13-Nendo$$sim$$Heisei-17-Nendo) Kenkyu Seika Hokokushu, p.179 - 203, 2006/03

no abstracts in English

JAEA Reports

Cross-field flow of plasma produced by electron beam evaporation

Takayanagi, Tomohiro*; Ikehata, Takashi*; Mase, Hiroshi*; Oba, Hironori; Shibata, Takemasa

JAERI-Research 2005-024, 14 Pages, 2005/09

JAERI-Research-2005-024.pdf:1.71MB

A weakly ionized plasma contained in the gadolinium atomic beam produced by electron beam heating was passed led to a magnetic field of 0$$sim$$$$pm$$1.5kG between iron cores. When the magnetic field was applied, the instability appeared in the ion saturation current. With increasing the magnetic field, the ions detected by the ion collectors decreased and no ions were detected at all. The magnetic field intensity at which the plasma does not flow and ions are not detected does not depend on plasma ion density. At this magnetic field, Larmor radius of ions are two times wider than plasma width. In addition, it is found that the plasma contained in the atomic beam can be removed by the magnetic field.

JAEA Reports

Study on the System Development for evaluating Long-term Alteration of Hydraulic Field in Near Field (IV) (Summary)

Okutsu, Kazuo*; Morikawa, Seiji*; Shimbo, Hiroshi*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Murakami, Takeshi*; Aoyama, Yuji*

JNC TJ8400 2005-013, 117 Pages, 2005/02

JNC-TJ8400-2005-013.pdf:3.24MB

To integrate the system for evaluation of long-term hydraulic condition in near field of TRU waste disposal, the engineered barrier, which consists of bentonite buffer and cementitious materials, was employed in the series of laboratory tests. On the bentonite buffer, with the aim of investigating of the effect of (i) interlayer cation in bentonite, (ii) content of siliceous sand and (iii) the ionic strength of ground water on its mechanical and hydraulic properties, series of laboratory tests were conducted. The same lot of bentonite was used in the series of tests to obtain consistent data. In addition, the swelling test of the laminated bentonite with caliumization front was conducted for verification of the proposed constitutive model. On cementitious materials, the altered specimen that produced immersing was investigated the water permeation and also characteristics. The hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated.

JAEA Reports

Study on the System Development for evaluating Long-term Alteration of Hydraulic Field in Near Field (IV)

Okutsu, Kazuo*; Morikawa, Seiji*; Shimbo, Hiroshi*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Murakami, Takeshi*; Aoyama, Yuji*

JNC TJ8400 2005-012, 272 Pages, 2005/02

JNC-TJ8400-2005-012.pdf:7.05MB

To integrate the system for evaluation of long-term hydraulic condition in near field of TRU waste disposal, the engineered barrier, which consists of bentonite buffer and cementitious materials, was employed in the series of laboratory tests.On the bentonite buffer, with the aim of investigating of the effect of (i)interlayer cation in bentonite, (ii)content of siliceous sand and (iii)the ionic strength of ground water on its mechanical and hydraulic properties, series of laboratory tests were conducted. The same lot of bentonite was used in the series of tests to obtain consistent data. In addition, the swelling test of the laminated bentonite with caliumization front was conducted for verification of the proposed constitutive model.On cementitious materials, the altered specimen that produced immersing was investigated the water permeation and also characteristics. The hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated.

Journal Articles

Event notification system with the PLC

Kawase, Masato*; Yoshikawa, Hiroshi; Sakaki, Hironao; Takahashi, Hiroki; Sako, Hiroyuki; Kamiya, Junichiro; Takayanagi, Tomohiro; Hongo, Reiji*

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.537 - 539, 2004/08

When an interlock occurs in the equipment, it is required to notify the upper rank control system of the Interlock and receive information for apparatus information in the upper rank control system as at high speed as possible. In the apparatus using FA-M3, it can respond to this by using the notice function of an event. This report shows the event notification system with a PLC based Kicker electromagnet power supply for 3GeVRCS.

Journal Articles

Effects of He/Electron irradiation on microstructure evolution in Be$$_{12}$$Ti

Shibayama, Tamaki*; Nakamichi, Masaru*; Uchida, Munenori*; Kawamura, Hiroshi; Kinoshita, Hiroshi*; Kiyanagi, Yoshiaki*; Takahashi, Heishichiro*; Nomura, Naoyuki*

JAERI-Conf 2004-006, p.216 - 219, 2004/03

no abstracts in English

Journal Articles

Current status of the AGS spallation target experiment

Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.

Proceedings of 6th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-6), (OECD/NEA No.3828), p.27 - 36, 2004/00

no abstracts in English

Journal Articles

Research activities on neutronics under ASTE collaboration at AGS/BNL

Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.

Journal of Nuclear Science and Technology, 39(Suppl.2), p.1155 - 1160, 2002/08

no abstracts in English

JAEA Reports

Conceptual design of solid breeder blanket system cooled by supercritical water

Enoeda, Mikio; Ohara, Yoshihiro; Akiba, Masato; Sato, Satoshi; Hatano, Toshihisa; Kosaku, Yasuo; Kuroda, Toshimasa*; Kikuchi, Shigeto*; Yanagi, Yoshihiko*; Konishi, Satoshi; et al.

JAERI-Tech 2001-078, 120 Pages, 2001/12

JAERI-Tech-2001-078.pdf:8.3MB

This report is a summary of the design works, which was discussed in the design workshop held in 2000 for the demonstration (DEMO) blanket aimed to strengthen the commercial competitiveness and technical feasibility simultaneously. The DEMO blanket must supply the feasibility and experience of the total design of the power plant and the materials. This conceptual design study was performed to determine the updated strategy and goal of the R&D of the DEMO blanket which applies the supercritical water cooling proposed in A-SSTR, taking into account the recent progress of the plasma research and reactor engineering technology.

45 (Records 1-20 displayed on this page)