Study on dryout and rewetting during accidents including ATWS for the BWR at JAEA

Satou, Akira; Wada, Yuki; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 354, p.110164_1 - 110164_10, 2019/12

https://doi.org/10.1016/j.nucengdes.2019.110164

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.

Study on fundamental process of seawater pool nucleate boiling heat transfer

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Thermal Science and Engineering, 25(4), p.65 - 74, 2017/10

no abstracts in English

Study on forced-convective boiling heat transfer of seawater with sea salt deposition

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Nagatake, Taku; Yoshida, Hiroyuki

Konsoryu, 31(2), p.162 - 170, 2017/06

https://doi.org/10.3811/jjmf.31.162

no abstracts in English

Numerical simulation of turbulent heat transfer behind a spacer with small-ribs in a subchannel

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.

Numerical analysis for heat transfer from a Cd poison in cryogenic hydrogen

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.

Estimation of heat transfer in moderators filled with cryogenic hydrogen for proton beam power of 1 MW

Tatsumoto, Hideki; Kato, Takashi; Aso, Tomokazu; Ushijima, Isamu*; Hasegawa, Shoichi; Otsu, Kiichi*

JAERI-Tech 2005-019, 16 Pages, 2005/03

JAERI-Tech-2005-019.pdf:1.29MB

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.

Heat transfer phenomenon of natural convection in an open vessel and its infrared sensing

Inagaki, Terumi*; Kaneko, Toshinobu*; Hatori, Masakazu*; Shiina, Yasuaki

Nihon Kikai Gakkai Rombunshu, B, 70(699), p.279 - 286, 2004/11

no abstracts in English

Advanced fusion technologies developed for JT-60 superconducting Tokamak

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

https://doi.org/10.1088/0029-5515/44/2/015

no abstracts in English

Thermal-hydraulic experiments and analyses of coupled moderator vessel for spallation neutron source

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

Effect of porous medium on heat transfer and flow in a circular tube

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.