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Uesawa, Shinichiro; Yamashita, Susumu; Sano, Yoshihiko*; Yoshida, Hiroyuki
Journal of Nuclear Science and Technology, 62(6), p.523 - 541, 2025/06
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Japan Atomic Energy Agency (JAEA) has developed a numerical method with the JUPITER code with a porous medium model to calculate the thermal behavior in PCVs of 1F. In this study, we performed an experiment and numerical simulation of the natural convective heat transfer with the porous medium to validate JUPITER with the porous medium model. In comparison of the temperature and velocity distributions between the experiment and simulation, the temperature distribution in the simulation was in good agreement with the distribution in the experiment except the temperature near the top surface of the porous medium. The velocity distribution also agreed qualitatively with the experimental result. In addition, we also performed the numerical simulations with various effective thermal conductivity models to discuss the effect of the conductivity based on the internal structure of porous media on the natural convective heat transfer. The result indicated that the temperature distribution in the porous medium and the velocity distribution of the natural convection were significantly different for each model, and thus the conductivity of the fuel debris was one of the key parameters of in the thermal behavior analysis in 1F.
Uchida, Kazuto*; Masuda, Tsukuru*; Hara, Shintaro*; Matsuo, Yoichi*; Liu, Y.*; Aoki, Hiroyuki; Asano, Yoshihiko*; Miyata, Kazuki*; Fukuma, Takeshi*; Ono, Toshiya*; et al.
ACS Applied Materials & Interfaces, 16(30), p.39104 - 39116, 2024/07
Times Cited Count：2 Percentile：51.81(Nanoscience & Nanotechnology)Yamada, Ryuji*; Kimura, Takashi*; Kariya, Yoshihiko*; Sano, Masaki*; Tsushima, Akane*; Li, Z.*; Nakatsuka, Takeshi*; Kokubu, Yoko; Inoue, Kimio*
Sabo Gakkai-Shi, 73(5), p.3 - 14, 2021/01
We discuss the applicability of dating methods for determining landslide chronologies in relation to the type of samples and the sampling location. Case studies are carried out with fossil wood samples buried in the colluvial soil of large-scale landslides occurred in two areas of the Japanese Alps region. Ages are determined by accelerator mass spectrometry radiocarbon dating and dendrochronological analysis using the oxygen isotope composition of tree ring cellulose. Most of ages for Dondokosawa rock avalanche are concordant with the period of AD 887 Ninna (Goki-Shichido) earthquake. Ages for Ohtsukigawa debris avalanche are not concentrated in a specific period. In order to obtain accurate age of large-scale landslide, utilizing buried large diameter tree trunk or branches with the good preservation condition has a lot of advantages because it allows us to compare the landslide chronology with historical records of heavy rainfall and large earthquakes.
Al conductor with stainless steel conduitKoizumi, Norikiyo; Takahashi, Yoshikazu; Nakajima, Hideo; Tsuchiya, Yoshinori; Matsui, Kunihiro; Nunoya, Yoshihiko; Ando, Toshinari; Hiyama, Tadao; Kato, Takashi; Isono, Takaaki; et al.
Teion Kogaku, 36(8), p.478 - 485, 2001/08
no abstracts in English
Al conductorKoizumi, Norikiyo; Ando, Toshinari; Takahashi, Yoshikazu; Matsui, Kunihiro; Nakajima, Hideo; Tsuchiya, Yoshinori; Kikuchi, Kenji; Nunoya, Yoshihiko; Kato, Takashi; Isono, Takaaki; et al.
Senshin A15-gata Kagobutsu Chodendo Senzai Shimpojiumu Rombunshu, p.5 - 9, 2000/00
no abstracts in English
Al insert to be tested in ITER central solenoid model coilKoizumi, Norikiyo; ; ; Takahashi, Yoshikazu; Sugimoto, Makoto; Nakajima, Hideo; Kato, Takashi; Nunoya, Yoshihiko; Ando, Toshinari; Tsuji, Hiroshi; et al.
IEEE Transactions on Magnetics, 32(4), p.2236 - 2239, 1996/07
Times Cited Count：11 Percentile：63.49(Engineering, Electrical & Electronic)no abstracts in English
Ito, Koki*; Sano, Yoshihiko*; Kuwahara, Fujio*; Uesawa, Shinichiro; Yoshida, Hiroyuki
no journal, ,
To estimate the thermal behavior of fuel debris in the primary containment vessel of the Fukushima Daiichi Nuclear Power Station, we have developed a numerical simulation method for analyzing the thermal behavior of fuel debris during air cooling. Since fuel debris is assumed to be a porous material, by using a porous medium model, the numerical simulation was conducted to simulate the natural convection in a closed vessel with porous materials. The simulation was validated by comparing it with the experiment in JAEA.
Uesawa, Shinichiro; Ono, Ayako; Yamashita, Susumu; Sano, Yoshihiko*; Yoshida, Hiroyuki
no journal, ,
To evaluate the thermal behavior of fuel debris of porous media in primary containment vessels (PCVs) of TEPCO's Fukushima Daiichi nuclear power station for air cooling, JAEA has developed a numerical simulation method using JUPITER code with porous medium models. In this presentation, we report the numerical simulation results of the thermal behavior in the PCV considering three porous structures of fuel debris, such as bubble dispersion, truss structure, and particle packed bed types. The results showed the temperature of the fuel debris was different for each model. It is important to understand the porous structure of the fuel debris for the thermal behavior because the structure has a strong effect on it.
