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

https://doi.org/10.1080/00223131.2017.1419888

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, AlO, ZrO, 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.

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

https://doi.org/10.1016/j.anucene.2017.09.011

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.

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

https://doi.org/10.1016/j.nima.2013.09.060

Visibility estimation for neutron resonance absorption radiography using a pulsed neutron source

Kai, Tetsuya; Maekawa, Fujio; Oshita, Hidetoshi*; Sato, Hirotaka; Shinohara, Takenao; Oi, Motoki; Harada, Masahide; Uno, Shoji*; Otomo, Toshiya*; Kamiyama, Takashi*; et al.

Physics Procedia, 43, p.111 - 120, 2013/00

https://doi.org/10.1016/j.phpro.2013.03.014

A neutron imaging instrument is in construction at the pulsed neutron source of J-PARC. Some demonstration experiments in NOBORU/J-PARC have carried. To explore widespread applications of the newly built instruments it is indispensable to indicate the range of coverage of this technique. In the presentation, the authors describe the results of some of demonstration measurements, and then compare all elements with the values obtained by multiplying peak cross section and peak widths of neutron resonances in evaluated nuclear data libraries. This value is expected to be a good measure to exhibit visibility of each element in this technique.

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

https://doi.org/10.1016/j.nima.2010.10.076

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 7.510, 1.610, and 1.110 n/cm/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.

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 10n/s/cm 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.

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.

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.

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