Numerical analysis of natural convective heat transfer with porous medium using JUPITER

Uesawa, Shinichiro; Yamashita, Susumu; Sano, Yoshihiko*; Yoshida, Hiroyuki

Journal of Nuclear Science and Technology, 62(6), p.523 - 541, 2025/06

https://doi.org/10.1080/00223131.2025.2451023

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.

Mass production of NbSn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4801904_1 - 4801904_4, 2012/06

https://doi.org/10.1109/TASC.2011.2178053

Japan Atomic Energy Agency is the first to start the mass production of the TF conductors in Phase IV in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The conductor is cable-in-conduit conductor with a central spiral. A total of 900 NbSn strands and 522 copper strands are cabled around the central spiral and then wrapped with stainless steel tape whose thickness is 0.1 mm. Approximately 60 tons of NbSn strands were manufactured by the two suppliers in December 2010. This amount corresponds to approximately 55% of the total contribution from Japan. Approximately 30% of the total contribution from Japan was completed as of February 2011. JAEA is manufacturing one conductor per month under a contract with two Japanese companies for strands, one company for cabling and one company for jacketing. This paper summarizes the technical developments including a high-level quality assurance. This progress is a significant step in the construction of the ITER machine.

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

Pulse operation test of the ITER central solenoid model coil using the JT-60 power supply

Terakado, Tsunehisa; Okano, Jun; Shimada, Katsuhiro; Miura, Yushi; Yamashita, Yoshiki*; Matsukawa, Makoto; Hosogane, Nobuyuki; Tsuji, Hiroshi; Ando, Toshinari*; Takahashi, Yoshikazu; et al.

JAERI-Tech 2001-056, 24 Pages, 2001/08

JAERI-Tech-2001-056.pdf:1.17MB

no abstracts in English

A Proposal of revised method for determination of large positive reactivity

Kaneko, Yoshihiko*; Shimakawa, Satoshi; Nagao, Yoshiharu; Yamashita, Kiyonobu; ; Yamane, Tsuyoshi

JAERI-Research 97-003, 70 Pages, 1997/02

JAERI-Research-97-003.pdf:1.79MB

no abstracts in English

Development of numerical simulation method to evaluate heat transfer of fuel debris in air cooling, 7; Effect of porous internal structure of fuel debris on thermal behavior in PCV

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.

Analysis of the tectonic history of Mizunami area, 2; Kinematics of the Tsukiyoshi Fault

Yamada, Yasuhiro*; Yamashita, Yoshihiko*; Miyakawa, Ayumu*; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Tagami, Masahiko

no journal, , 

Tsukiyoshi fault displaces Toki granite and middle Miocene Mizunami group, and it was regarded as the reverse fault from apparent displacement. However, the arrangement of the Tsukiyoshi channel and several NNW-SSE trend faults between the right step region of ENE-WSW strike Tsukiyoshi Fault. This implies that right-lateral displacement created a pull-apart basin. In order to support this working hypothesis, we have designed analogue experiment and 3-D numerical simulation, to restore a similar structure around the southern side of Tsukiyoshi fault. It succeeded in reproducing similar structures of the present geological model in analogue experiment by dextral moving the reduced 3-D block model of the present Tsukiyoshi fault plane.