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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.; Oi, Motoki; Harada, Masahide; Iikura, Hiroshi; et al.

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

 Times Cited Count:15 Percentile:96.95(Instruments & Instrumentation)

Journal Articles

Sedimentation behavior of mixed solid particles

Sheikh, Md. A. R.*; Son, E.*; Kamiyama, Motoki*; Morioka, Toru*; Matsumoto, Tatsuya*; Morita, Koji*; Matsuba, Kenichi; Kamiyama, Kenji; Suzuki, Toru*

Journal of Nuclear Science and Technology, 55(6), p.623 - 633, 2018/06

 Times Cited Count:5 Percentile:64.98(Nuclear Science & Technology)

During core-disruptive accidents in sodium-cooled fast reactors, the sedimentation behavior of fragmented debris is crucial for in-vessel retention. The height of the beds formed may influence both the cooling of the bed and the neutronic characteristics. To develop an experimental database of bed formation behavior, a series of experiments using simulant materials, namely, Al$$_{2}$$O$$_{3}$$, ZrO$$_{2}$$, and stainless steel, were performed under gravity-driven discharge of solid particles from a nozzle into a quiescent cylindrical water pool. The bed height was measured for particles of different size, density, and sphericity, and an injection nozzle with varying diameter, injection velocity, and injection height. From these experiments, an empirical correlation was established to predict the bed height for both homogeneous and mixed particles for the different properties. This correlation reproduces reasonably well the experimental trend in bed height.

Journal Articles

Measurements of neutronic characteristics of rectangular and cylindrical coupled hydrogen moderators

Kai, Tetsuya; Kamiyama, Takashi*; Hiraga, Fujio*; Oi, Motoki; Hirota, Katsuya*; Kiyanagi, Yoshiaki*

Journal of Nuclear Science and Technology, 55(3), p.283 - 289, 2018/03

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Journal Articles

Experimental study on debris bed characteristics for the sedimentation behavior of solid particles used as simulant debris

Shamsuzzaman, M.*; Horie, Tatsuro*; Fuke, Fusata*; Kamiyama, Motoki*; Morioka, Toru*; Matsumoto, Tatsuya*; Morita, Koji*; Tagami, Hirotaka; Suzuki, Toru*; Tobita, Yoshiharu

Annals of Nuclear Energy, 111, p.474 - 486, 2018/01

 Times Cited Count:7 Percentile:77.16(Nuclear Science & Technology)

Journal Articles

Experimental database for bed formation behaviors of solid particles

Sheikh, M. A. R.*; Son, E.*; Kamiyama, Motoki*; Morioka, Toru*; Matsumoto, Tatsuya*; Morita, Koji*; Matsuba, Kenichi; Kamiyama, Kenji; Suzuki, Toru

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 10 Pages, 2016/11

During the material relocation phase of core disruptive accidents in sodium-cooled fast reactors, the sedimentation behavior of fragmented debris leading to the formation of debris beds is crucial for in-vessel retention by debris bed cooling. In this study, a series of experiments using simulant materials was performed to develop an experimental database of bed formation behavior by gravity driven discharge of solid particles from a nozzle into a quiescent cylindrical water pool. The bed height as well as the bed shape was measured. Three types of spherical and non-spherical particles, namely Al$$_{2}$$O$$_{3}$$, ZrO$$_{2}$$ and stainless steel with different size were employed to study the effect of key experimental parameter on debris bed mound shape. Based on the experimental results, an empirical correlation as experimental database was proposed to predict the particle bed height. The proposed correlation reasonably reproduces the experimental trend of the bed height variation on the crucial factors. This result demonstrates a wide applicability of the proposed empirical model to predict the bed height in terms of all crucial factors with reasonable accuracy.

Journal Articles

Experimental investigation on characteristics of mixed particle debris in sedimentation and bed formation behavior

Sheikh, M. A. R.*; Son, E.*; Kamiyama, Motoki*; Morioka, Toru*; Matsumoto, Tatsuya*; Morita, Koji*; Matsuba, Kenichi; Kamiyama, Kenji; Suzuki, Toru

Proceedings of 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-11) (USB Flash Drive), 12 Pages, 2016/10

This paper reports an experimental evaluation on debris bed formation characteristics in core-disruptive accidents cogitating the heterogeneous mixture of particles. In the present study, to appraise the characteristics, a series of experiments was accomplished by gravity driven discharge of solid binary mixtures of particles as simulant debris from a nozzle into a quiescent water pool in isothermal condition at room temperature. Currently, two types of spherical particles, namely Alumina and stainless steel with different diameter are employed to study the effect of key experimental parameters on bed mound shape. In experimental investigation both convex and concave mound shapes were perceived based on the effect of particle size and nozzle diameter. The present outcomes could be useful to validate numerical models and simulation codes of particulate debris sedimentation.

Journal Articles

Energy resolution of pulsed neutron beam provided by the ANNRI beamline at the J-PARC/MLF

Kino, Koichi*; Furusaka, Michihiro*; Hiraga, Fujio*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Furutaka, Kazuyoshi; Goko, Shinji*; Hara, Kaoru; Harada, Hideo; Harada, Masahide; et al.

Nuclear Instruments and Methods in Physics Research A, 736, p.66 - 74, 2014/02

 Times Cited Count:22 Percentile:90.45(Instruments & Instrumentation)

Journal Articles

Neutron resonance imaging of a Au-In-Cd alloy for the JSNS

Oi, Motoki; Teshigawara, Makoto; Kai, Tetsuya; Harada, Masahide; Maekawa, Fujio; Futakawa, Masatoshi; Hashimoto, Eiko*; Segawa, Mariko; Kureta, Masatoshi; Tremsin, A.*; et al.

Physics Procedia, 43, p.337 - 342, 2013/04

 Times Cited Count:6 Percentile:91.93

The Japan Spallation Neutron Source (JSNS) at the Japan Proton Accelerator Research Complex (J-PARC) had been developed as a 1-MW spallation neutron source. A Au-In-Cd alloy has been proposed as a new decoupler material. Recently, we successfully produced the ternary Au-In-Cd alloy. The alloy composition is 74.9 at% Au, 0.5 at% In, and 24.6 at% Cd. We used the pulsed neutron imaging techniques to measure the elements in the Au-In-Cd alloy. Both a time gated camera system and a multi-channel plate (MCP) detector were used as detectors. Measurement was performed at BL10 in the JSNS. A Au-In-Cd specimen, In foil and two Au foils are used as a sample. As a results, we could obtain distribution of Au, In and Cd in the Au-In-Cd specimens distinctly.

Journal Articles

Experimental studies of the effect of the ortho/para ratio on the neutronic performance of a liquid hydrogen moderator for a pulsed neutron source

Oi, Motoki; Ogawa, Hirotatsu*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*

Nuclear Instruments and Methods in Physics Research A, 659(1), p.61 - 68, 2011/12

 Times Cited Count:8 Percentile:58.2(Instruments & Instrumentation)

Liquid hydrogen is a realistic cold moderator material for high-power spallation neutron sources. The neutronic performance of a hydrogen moderator depends on the ortho/para ratio of the hydrogen, and thus experimental data are needed that will clarify the ortho/para ratio effects on neutronic performance. In this study, we measured the neutronic performance of a liquid hydrogen moderator at several para-hydrogen ratios. The neutron energy spectra changes within 20%, depending on the para-hydrogen ratios. With increasing para-hydrogen ratio, the pulse peak intensity increases and the pulse width becomes narrower. With a decoupled moderator, the pulse decay becomes faster. In comparison with the figure of merit (FOM), the para-hydrogen moderator showed almost the same performance as that of the methane moderator considered to be the best moderator for the pulsed neutron source.

Journal Articles

Measurement of energy spectra and spatial distributions of neutron beams provided by the ANNRI beamline for capture cross-section measurements at the J-PARC/MLF

Kino, Koichi*; Furusaka, Michihiro*; Hiraga, Fujio*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Furutaka, Kazuyoshi; Goko, Shinji*; Harada, Hideo; Harada, Masahide; Kai, Tetsuya; et al.

Nuclear Instruments and Methods in Physics Research A, 626-627, p.58 - 66, 2011/01

 Times Cited Count:37 Percentile:94.9(Instruments & Instrumentation)

We measured the energy spectra and spatial distributions of the neutron beam of ANNRI beamline at the Japan Proton Accelerator Research Complex / Materials and Life Science Experimental Facility (J-PARC/MLF). Our research team designed and built this beamline to measure nuclear data with high precision. The measurements were performed on three types of beams provided by the beamline in the neutron energy range of 1.5 meV to 10 keV. The energy spectra show a typical feature of para-hydrogen moderator, and the absolute intensities almost agree with predictions based on both a simulation calculation of the JSNS (Japan Spallation Neutron Source) and a neutron transmission calculation of the beamline. The available neutron intensities at 21.5 m are 7.5$$times$$10$$^{5}$$, 1.6$$times$$10$$^{4}$$, and 1.1$$times$$10$$^{5}$$ n/cm$$^{2}$$/sec in the energy ranges of 1.5-25 meV, 0.9-1.1 eV, and 0.9-1.1 keV, respectively, under the 17.5 kW JSNS operation. The measured spatial distributions of the beams formed by three different collimators are consistent with those expected from the collimator-system design of the beamline. The beam sizes in FWHM are about 29, 14, and 11 mm for the three different beam collimators. The edges of the spatial distributions are relatively sharp, enabling us to measure the nuclear data successfully.

Journal Articles

First neutron production utilizing J-PARC pulsed spallation neutron source JSNS and neutronic performance demonstrated

Maekawa, Fujio; Harada, Masahide; Oikawa, Kenichi; Teshigawara, Makoto; Kai, Tetsuya; Meigo, Shinichiro; Oi, Motoki; Sakamoto, Shinichi; Takada, Hiroshi; Futakawa, Masatoshi; et al.

Nuclear Instruments and Methods in Physics Research A, 620(2-3), p.159 - 165, 2010/08

 Times Cited Count:63 Percentile:97.68(Instruments & Instrumentation)

The J-PARC 1-MW pulsed spallation neutron source JSNS was successfully launched on 30th of May 2008. To demonstrate the unique features of the moderator design and the neutronic performance of JSNS the neutron spectral intensity, absolute neutron flux, and time structure of the neutron pulse shapes etc have been measured using several neutron instruments since then. The measured energy spectra clearly revealed the feature of the para-hydrogen, as expected when designing the moderator. The measured neutron flux below 0.4 eV agreed with the corresponding design value within $$pm$$20%, thus suggesting that the JSNS design calculations to have been reliable. World-class high-resolution diffraction data could be recorded due to the suitability of design of the moderators and the instruments. Another world-class high-intensity neutron flux was also capable of being demonstrated due to the unique design of the large cylindrical coupled moderator.

Journal Articles

Distinctive features in neutronic performance of JSNS

Maekawa, Fujio; Oikawa, Kenichi; Harada, Masahide; Teshigawara, Makoto; Kai, Tetsuya; Kasugai, Yoshimi; Meigo, Shinichiro; Oi, Motoki; Futakawa, Masatoshi; Watanabe, Noboru*; et al.

Proceedings of 19th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-19) (CD-ROM), 8 Pages, 2010/07

Efforts have been made to characterize neutronic performance of JSNS. A NOBORU instrument was mainly used for this purpose while some other instruments were used when needed. The followings were confirmed. (1) Judging from a measured spectral shape, a para-hydrogen fraction in the hydrogen moderator was very close to unity as expected due to introduction of catalyst in a hydrogen circulation system. (2) Measured data for absolute spectral intensity and pulse shapes agreed very well with simulation calculations, and suggested adequacy of the neutron source designs. (3) The world's highest resolution of 0.035 % was recorded at the powder diffractometer SuperHRPD. (4) A total neutron flux of 3 $$times$$ 10$$^{9}$$n/s/cm$$^{2}$$ was confirmed at the chopper instrument 4SEASONS when it was normalized to 1 MW. The flux is the world's highest among existing spallation neutron sources, and is comparable to fluxes at intense reactor sources even in time-averaged value.

Oral presentation

Measurement of neutronic performance of J-PARC type coupled moderator

Kai, Tetsuya; Kamiyama, Takashi*; Hiraga, Fujio*; Hirota, Katsuya*; Oi, Motoki; Maekawa, Fujio; Kato, Takashi; Kiyanagi, Yoshiaki*

no journal, , 

no abstracts in English

Oral presentation

Pulse neutron imaging experiments in the first year of J-PARC

Kai, Tetsuya; Harada, Masahide; Oikawa, Kenichi; Sakai, Kenji; Maekawa, Fujio; Oi, Motoki; Shinohara, Takenao; Aizawa, Kazuya; Takata, Shinichi; Arai, Masatoshi; et al.

no journal, , 

Development of imaging techniques with pulse neutrons were started using the NeutrOn Beam-line for Observation and Research Use (NOBORU) of J-PARC at December 2008. The results in the first three months, future research plans and discussions on a new imaging facility in J-PARC are shown.

Oral presentation

Development of pulsed neutron imaging technique at J-PARC

Shinohara, Takenao; Takata, Shinichi; Aizawa, Kazuya; Suzuki, Junichi; Kai, Tetsuya; Harada, Masahide; Oikawa, Kenichi; Maekawa, Fujio; Sakai, Kenji; Oi, Motoki; et al.

no journal, , 

no abstracts in English

Oral presentation

Recent developments of RITS code for Bragg edge imaging

Sato, Hirotaka; Shinohara, Takenao; Kiyanagi, Ryoji; Aizawa, Kazuya; Oi, Motoki; Harada, Masahide; Oikawa, Kenichi; Maekawa, Fujio; Iwase, Kenji*; Kamiyama, Takashi*; et al.

no journal, , 

Bragg edge imaging at a pulsed neutron source is a new tool to study engineering materials, which can simultaneously give crystalline structural information in a bulk specimen over wide area with good spatial resolution. In order to quantitatively deduce such information from the Bragg edge transmission spectrum at each pixel of a two-dimensional position sensitive detector, it is indispensable to analyze the shape of each Bragg edge in detail. Therefore, a comprehensive spectral analysis code "RITS" has been developed, and we have successfully demonstrated the quantitative imaging of not only crystal lattice strain but also crystallographic texture (preferred orientation) and crystallite block size. Furthermore, we are improving the code since it has not dealt with all crystal structures of 230 space groups, and not applicable to materials composed of multi crystalline phases. In the presentation, we will report the recent developments of the advanced Bragg edge imaging techniques.

Oral presentation

Feasible elements for resonance absorption radiography with pulsed neutrons

Kai, Tetsuya; Maekawa, Fujio; Kamiyama, Takashi*; Segawa, Mariko; Oi, Motoki; Harada, Masahide; Shinohara, Takenao; Sato, Hirotaka*; Kiyanagi, Yoshiaki*

no journal, , 

no abstracts in English

Oral presentation

Present status of a new pulsed neutron imaging instrument in J-PARC MLF

Shinohara, Takenao; Kai, Tetsuya; Segawa, Mariko; Oi, Motoki; Oikawa, Kenichi; Harada, Masahide; Nakatani, Takeshi; Sakai, Kenji; Iikura, Hiroshi; Aizawa, Kazuya; et al.

no journal, , 

no abstracts in English

Oral presentation

Present status of a new pulsed neutron imaging instrument at J-PARC

Segawa, Mariko; Shinohara, Takenao; Kai, Tetsuya; Iikura, Hiroshi; Oi, Motoki; Oikawa, Kenichi; Harada, Masahide; Sakai, Kenji; Soyama, Kazuhiko; Aizawa, Kazuya; et al.

no journal, , 

Oral presentation

Progress of constructing energy-resolved neutron imaging system at J-PARC MLF

Shinohara, Takenao; Oikawa, Kenichi; Segawa, Mariko; Iikura, Hiroshi; Harada, Masahide; Nakatani, Takeshi; Oi, Motoki; Sato, Hirotaka*; Kamiyama, Takashi*; Yokota, Hideo*; et al.

no journal, , 

Construction of the Energy-Resolved Neutron Imaging System (ERNIS) has started in 2012 at the Material and Life science experimental Facility (MLF) of J-PARC. Beam line shields, a new beam shutter, in-shield devices except a T0 chopper, sample stages and detector stages have been installed in the fiscal year ended March 2013. The first beam will be delivered in November 2014. After on-beam commissioning use programs are planned to start in 2015. In this presentation progress of the construction is introduced, and then characteristics of ERNIS are discussed.

28 (Records 1-20 displayed on this page)