Numerical simulation of the solid particle sedimentation and bed formation behaviors using a hybrid method

Sheikh, M. A. R.*; Liu, X.*; Matsumoto, Tatsuya*; Morita, Koji*; Guo, L.*; Suzuki, Toru*; Kamiyama, Kenji

Energies (Internet), 13(19), p.5018_1 - 5018_15, 2020/10

https://doi.org/10.3390/en13195018

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 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 AlO, ZrO 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.

Assessment report of research and development activities in FY2014; Activity "Research and development on high-temperature gas-cooled reactor and related hydrogen production technology"

Tatematsu, Kenji; Matsumoto, Hiroyuki

JAEA-Evaluation 2015-001, 91 Pages, 2015/06

JAEA-Evaluation-2015-001.pdf:14.25MB

President of Japan Atomic Energy Agency consulted with the "Evaluation Committee of Research Activities for High-Temperature Gas-Cooled Reactor and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee"), which consists of specialists in the fields of the evaluation subjects of high-temperature gas-cooled reactor and related hydrogen production technology. The evaluation concludes that an overall judgment is A, because the outcome of the 2nd midterm plan has been obtained as planed in terms of advancing the safety and the practical use in each of the high-temperature gas-cooled reactor technology and the hydrogen production technology. As a result the technological goal has been achieved. Another key outcome obtained is that the achievement for a part of the next midterm plan has been accelerated with the construction of a continuous hydrogen production test facility. In addition, the contents of the 3rd period mid- to long- term plan (draft) are acceptable because they sufficiently reflect the interim report of the high-temperature gas-cooled reactor technical research and development working group organized by the MEXT. This report lists the members of the Evaluation Committee and outlines the method and procedure of the assessment. The results of the assessment by the Evaluation Committee are attached from Page 7.

Giant cadherins Fat and Dachsous self-bend to organize properly spaced intercellular junctions

Tsukasaki, Yoshikazu*; Miyazaki, Naoyuki*; Matsumoto, Atsushi; Nagae, Shigenori*; Yonemura, Shigenobu*; Tanoue, Takuji*; Iwasaki, Kenji*; Takeichi, Masatoshi*

Proceedings of the National Academy of Sciences of the United States of America, 111(45), p.16011 - 16016, 2014/11

https://doi.org/10.1073/pnas.1418990111

Assessment report of research and development activities; Activity "Research and development on high-temperature gas-cooled reactor and related hydrogen production technology"

Tatematsu, Kenji; Matsumoto, Hiroyuki

JAEA-Evaluation 2014-003, 131 Pages, 2014/09

JAEA-Evaluation-2014-003.pdf:26.08MB

Japan Atomic Energy Agency consulted with "Evaluation Committee of Research Activities for High-Temperature Gas-Cooled Reactor and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee") which consists of specialists in the fields of the evaluation subjects of high-temperature gas-cooled reactor and related hydrogen production technology. The evaluation concludes that Japan needs to have the high-temperature gas-cooled reactor and hydrogen production technology because it is important that the nuclear energy be utilized to meet heat demand in order to contribute to the emission reduction of carbon dioxide in industry and transportation sectors. Therefore, the research and development should continue with the use of the High Temperature Engineering Test Reactor and the aim of establishing the basic technology. This report lists the members of the Evaluation Committee and the Expert Committee and outlines the method and procedure of the assessment. The result of the assessment by the Committees are attached from page 7.

Magnetic properties of single crystalline YbFeO

Yoshii, Kenji; Mizumaki, Masaichiro*; Matsumoto, Keisuke*; Mori, Shigeo*; Endo, Naruki; Saito, Hiroyuki; Matsumura, Daiju; Kambe, Takashi*; Ikeda, Naoshi*

Journal of Physics; Conference Series, 428, p.012032_1 - 012032_5, 2013/04

https://doi.org/10.1088/1742-6596/428/1/012032

We have investigated a single crystal of multiferroic YbFeO. Its magnetic transition temperature was 250 K. The magnetization along the c-axis was much larger than that within the ab plane, indicating the Ising character of this system. The field-cooled magnetization became negative below 10 K. This was explained in terms of an antiparallel coupling between Yb and Fe moments. Magnetocaloric effects were also observed. The change of entropy was found to show a broad peak with a width of 100 K, which is favorable to application.

Experimental studies and empirical models for the transient self-leveling behavior in debris bed

Cheng, S.*; Tanaka, Yohei*; Gondai, Yoji*; Kai, Takayuki*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.

Journal of Nuclear Science and Technology, 48(10), p.1327 - 1336, 2011/10

https://doi.org/10.3327/jnst.48.1327

To clarify this behavior, a series of experiments have been performed in which nitrogen gas has been percolated uniformly through a particle bed. In these experiments, solid particles and water contained in a rectangular tank simulate respectively fuel debris and coolant. Based on the data obtained, an empirical model was developed to describe the transient variation in the bed inclination angle during the self-leveling process. Good agreement has been obtained between calculated and experimental values. Verification of the model has been confirmed through detailed analysis of the effects of experimental parameters such as particle size, particle density, and gas flow rate. Its applicability to extended conditions was further discussed by performing modeling simulations and comparing results against experimental data obtained from a larger-scale experimental system that employed a conventional boiling method.

Collapsing processes of charge ordered structure in charge- and spin- frustrated ferrite YbFeO

Matsumoto, Keisuke*; Koyama, Tsukasa*; Mori, Shigeo*; Yoshii, Kenji; Ikeda, Naoshi*

Journal of Physics; Conference Series, 320, p.012085_1 - 012085_5, 2011/09

https://doi.org/10.1088/1742-6596/320/1/012085

In order to clarify the stability of charge ordered structure (CO) in charge- and spinfrustrated ferrite YbFeO, we have investigated changes of the CO structure by partial substitution of Mn for Fe in YbFeO by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that subtle substitution of Mn for Fe in YbFeO destroyed drastically the CO structure with the wave vector of q=1/3 1/3 1/2 and, instead, induced polar clustering structure characterized by honeycomb shaped diffuse scatterings in the reciprocal space. The formation of polar clustering structure should be responsible for the characteristic dielectric dispersion.

Experimental investigation on self-leveling behavior in debris beds

Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu

Nuclear Engineering and Design, 241(1), p.366 - 377, 2011/01

https://doi.org/10.1016/j.nucengdes.2010.11.013