Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Satou, Akira; Wada, Yuki; Shibamoto, Yasuteru; Yonomoto, Taisuke
Nuclear Engineering and Design, 354, p.110164_1 - 110164_10, 2019/12
Times Cited Count:8 Percentile:65.94(Nuclear Science & Technology)JAEA has conducted a series of experimental researches on the Post-boiling transition heat transfer, transient critical heat flux and rewetting for BWRs. Experimental data bases covering the anticipated operational conditions was developed; the significance of the precursor cooling was identified. This paper presents approaches of the present research focusing on the anticipated transient without scram, effects of the spacer and physical understanding of the phenomena for development of mechanistic model together with promising results obtained so far.
Satou, Akira; Wada, Yuki; Le, T. D.; Shibamoto, Yasuteru; Yonomoto, Taisuke
Proceedings of ANS International Conference on Best Estimate Plus Uncertainties Methods (BEPU 2018) (USB Flash Drive), 12 Pages, 2018/00
Experiments were performed under the condition of AOO for BWRs to obtain Post-BT heat transfer rate, deposition rates of liquid droplets, and the rewetting behavior after the core dryout. Rewetting behavior was analytically investigated and a relation among the rewetting velocity, the hot wall temperature, and the heat transfer rates in the precursory cooling and wetted regions were obtained. In addition, experiments simulating the condition of ATWS were newly performed with simulated ferrule spacers especially to investigate the spacer effect. It was found that the heat transfer rates were enhanced by the spacers, which were compared with existing prediction models for the validation. The spacers also appeared to increase the rewetting velocity slightly. Since the precursory cooling was found to play an important role on the rewetting behavior through the series of prior experiments, new experiments are conducted focusing on the precursory cooling. In those experiments, the behaviors of liquid film and droplets around the rewetting front were observed to investigate the mechanism of the precursory cooling.
Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Thermal Science and Engineering, 25(4), p.65 - 74, 2017/10
no abstracts in English
Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 7 Pages, 2017/07
Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Nagatake, Taku; Yoshida, Hiroyuki
Konsoryu, 31(2), p.162 - 170, 2017/06
no abstracts in English
Yoshida, Hiroyuki; Uesawa, Shinichiro; Yamashita, Susumu; Nagase, Fumihisa
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11
Takase, Kazuyuki
Proceedings of OECD/NEA & IAEA Workshop on Application of CFD/CMFD Codes to Nuclear Reactor Safety and Design and their Experimental Validation (CFD4NRS-5) (Internet), 11 Pages, 2014/09
When devising the thermal design of supercritical water reactors, it is necessary to develop an analysis method that correctly predicts the turbulent heat transfer characteristics in subchannels of fuel bundles. Spacers are set into the subchannels to maintain the distances between adjacent fuel rods. The turbulent heat transfer is generally enhanced by the spacers' reduction of the cross-sectional area in the subchannels. However, since the thermophysical properties of supercritical fluids drastically change in the vicinity of a pseudocritical point, the enhancement of the turbulent heat transfer depends on the thermal design. To this end, the Japan Atomic Energy Agency is developing an analysis method that will predict the thermal-hydraulic characteristics of supercritical fluids. The heat transfer calculations were performed using a newly developed code under conditions of a subchannel with a spacer. The enhancement of the turbulent heat transfer coefficient in the subchannels with spacers was analyzed numerically.
Aso, Tomokazu; Monde, Masanori*; Sato, Hiroshi; Hino, Ryutaro; Tatsumoto, Hideki; Kato, Takashi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 5(3), p.179 - 189, 2006/09
no abstracts in English
Tatsumoto, Hideki; Kato, Takashi; Aso, Tomokazu; Hasegawa, Shoichi; Ushijima, Isamu*; Otsu, Kiichi*; Ikeda, Yujiro
LA-UR-06-3904, Vol.2, p.426 - 434, 2006/06
In JSNS, Cadmium has been selected as a poison material in a hydrogen moderator to obtain narrow neutron pulse. The concern to adopt to Cd is how to bond Cd and Al alloy plate. R&Ds for bonding have been performed. But good bonding has not been obtained. Consequently, heat transfer between Cd poison and cryogenic hydrogen was studied for the case of insufficient bonding. The heat transfers for various bonding ratios were analyzed by CFD code (STAR-CD) without any turbulence model. The temperature rise in Cd poison for insufficient bonding was estimated. As a result, even the case of the bonding ratio of only 5 %, the maximum temperature of Cd is around 75K. Therefore, the expected heat transfer between the Cd poison and the hydrogen should be sufficient for insufficient bonding. Then, it is found that the any bonding method should be available for manufacturing method of Cd poison.
Aso, Tomokazu; Monde, Masanori*; Sato, Hiroshi; Tatsumoto, Hideki; Kato, Takashi; Ikeda, Yujiro
LA-UR-06-3904, Vol.2, p.385 - 394, 2006/06
no abstracts in English
Tatsumoto, Hideki; Kato, Takashi; Aso, Tomokazu; Ushijima, Isamu*; Hasegawa, Shoichi; Otsu, Kiichi*
JAERI-Tech 2005-019, 16 Pages, 2005/03
As one of the main experimental facilities in J-PARC, an intense spallation neutron source (JSNS) is constructed. In JSNS, cryogenic hydrogen with temperature of 20 K and pressure of 0.5 to 1.5 MPa was selected as the moderator. The total nuclear heating at the moderators is estimated to be 3.7 kW for proton beam power of 1 MW. A cryogenic hydrogen circulation system, which plays a role in cooling spallation neutron and moderators, has been designed. For a certain operation condition, it is possible to occur boiling in the moderators. The boiling phenomenon would have an influence on the neutronic performance and the safety of the moderators. The heat transfer mechanism of cryogenic hydrogen in the moderators needs to be estimated. However, the mechanism has not been clarified until now. In this paper, the heat transfer of cryogenic hydrogen was estimated by using properties of cryogenic hydrogen and the heat transfer correlations used in other fluids, and then the operation condition of the cryogenic hydrogen system has been considered.
Inagaki, Terumi*; Hatori, Masakazu*; Suzuki, Tomohiro*; Shiina, Yasuaki
Proceedings of International Conference on Advanced Optical Diagnostics in Fluids, Solids and Combustion (VSJ-SPIE '04) (CD-ROM), 9 Pages, 2004/12
no abstracts in English
Inagaki, Terumi*; Kaneko, Toshinobu*; Hatori, Masakazu*; Shiina, Yasuaki
Nihon Kikai Gakkai Rombunshu, B, 70(699), p.279 - 286, 2004/11
no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
Times Cited Count:7 Percentile:22.88(Physics, Fluids & Plasmas)no abstracts in English
Aso, Tomokazu; Sato, Hiroshi; Kaminaga, Masanori; Hino, Ryutaro; Monde, Masanori*
Kashika Joho Gakkai-Shi, 23(Suppl.2), p.13 - 16, 2003/10
no abstracts in English
Aso, Tomokazu; Sato, Hiroshi; Kaminaga, Masanori; Hino, Ryutaro; Monde, Masanori*
Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2003) Koen Rombunshu (No.030-3), p.45 - 46, 2003/09
no abstracts in English
Shiina, Yasuaki; Inagaki, Terumi*
Nihon Kikai Gakkai Rombunshu, B, 69(681), p.1233 - 1241, 2003/05
In order to reduce phase change time in latent heat technology, improvement of effective thermal conductivity of heat storage unit would be one of the techniques. Effect of effective thermal conductivity on melting time are studied analytically of circular composite heat storage capsules made by immersing phase change materials (PCM) into porous metals. Numerical and approximate analysis were made with the consideration of uniform and non-uniform heat transfer coefficients around the cylindrical surface. Four PCMs (HO,Octadecane, LiCO, NaCl) and three metals (copper, aluminum and carbon steel) were selected specific materials. Porosity of the metals were restricted larger than 0.9 in order to lessen decrease in latent heat. Results show that reduction in melting time was obtained for the above PCMs, especially for low conductivity PCMs. Melting time obtained by approximate analysis agrees well with numerical analysis. High Nusselt number and high thermal conductivity of heat transfer fluid would be more effective to reduce phase change time.
Uemura, Takuya*; Takeda, Tetsuaki; Ichimiya, Koichi*
Nihon Kikai Gakkai Yamanashi Koenkai Koen Rombunshu (020-4), p.49 - 50, 2002/10
A heat transfer experiment was performed using a horizontal circular tube to obtain the heat transfer and fluid flow characteristics in the tube inserted copper wire. From the results obtained in this experiment, it was found that an amount of heat removal in the tube with copper wire inserts increased about 20% comparing with a tube having a smooth wall. A heat transfer coefficient of the tube inserted copper wire also increased 30% to 50% under the constant pumping power condition.
Yonomoto, Taisuke; Otsu, Iwao; Nakamura, Hideo; Kondo, Masaya; Svetlov, S.*
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.215 - 220, 2002/06
no abstracts in English