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Hamamoto, Shimpei; Ohashi, Hirofumi; Iigaki, Kazuhiko; Shimazaki, Yosuke; Ono, Masato; Shimizu, Atsushi; Ishitsuka, Etsuo
Proceedings of 2021 International Congress on Advances in Nuclear Power Plants (ICAPP 2021) (USB Flash Drive), 6 Pages, 2021/10
Since the HTGR has a large amount of graphite material in the core, it is necessary to assume an accident in which the reactor pressure boundary is damaged and air flows into the core. It is important to state that at the time of this accident, graphite does not burn and the accident does not develop due to the heat of oxidation reaction. Therefore, in this study, in order to evaluate the combustibility of graphite materials, we propose a method to compare the calorific value and heat removal amount of the material. When calculating the calorific value, the structural material of HTTR, a high-temperature gas reactor in Japan, was used as a reference. The amount of air in contact with the structural material is a value determined from the chimney effect. The amount of heat release is the sum of convection and radiation. As a result of comparing the heat generation amount with the heat removal amount, it was shown that the heat release amount was always larger than the heat generation amount. This result shows that the graphite material does not depend on the state at the time of the air inflow accident, the temperature decreases and does not burn. It is important to clearly explain the non-flammability of graphite materials when deciding how to deal with severe accidents in HTGRs. This quantitative evaluation method based on a simple theory is considered useful.
Sato, Hiroyuki; Ohashi, Hirofumi; Nakagawa, Shigeaki
Mechanical Engineering Journal (Internet), 4(3), p.16-00495_1 - 16-00495_11, 2017/06
This paper intends to propose a practical solution to protect the HTR from severe oxidation against air ingress accidents without reliance on subsystems. Firstly, a change is made to the center reflector structure to minimize temperature difference during the accident condition in order to reduce buoyancy-driven natural circulation in the reactor. Secondly, a modified structure of the upper reflector is suggested to prevent massive air ingress against a rupture in standpipes. As a preliminary study, a numerical analysis is performed for a typical prismatic-type HTGR. The results showed that amount of air ingress into the reactor can be significantly reduced with practical changes to local structure in the reactor.
Sato, Hiroyuki; Ohashi, Hirofumi; Nakagawa, Shigeaki
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 8 Pages, 2016/06
This paper intends to propose a practical solution to protect HTGR from severe oxidation against air ingress accidents without reliance on subsystems. Firstly, a change is made to the center reflector structure to minimize temperature difference during the accident condition in order to reduce buoyancy-driven natural circulation in the reactor. Secondly, a modified structure of the upper reflector is suggested to prevent massive air ingress against a rupture in standpipes. As a preliminary study, a numerical analysis is performed for a typical prismatic-type HTGR to study the effectiveness of the proposed design concept using simplified lumped element models. The results showed that amount of air ingress into the reactor can be significantly reduced with practical changes to local structure in the reactor.
Takase, Kazuyuki
Fusion Engineering and Design, 51-52(Part.B), p.631 - 639, 2000/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
Takeda, Tetsuaki; Hishida, Makoto*
Nuclear Engineering and Design, 200(1-2), p.251 - 259, 2000/08
Times Cited Count：26 Percentile：82.67(Nuclear Science & Technology)no abstracts in English
Takase, Kazuyuki
Nihon Kikai Gakkai 2000-Nendo Nenji Taikai Koen Rombunshu, 1, p.607 - 608, 2000/00
no abstracts in English
*; Okamoto, Koji*; *; Fumizawa, Motoo
Nihon Kikai Gakkai Rombunshu, B, 63(615), p.82 - 89, 1997/11
no abstracts in English
Takeda, Tetsuaki; Takenaka, Satsuki*; Hishida, Makoto
Nihon Genshiryoku Gakkai-Shi, 38(2), p.154 - 162, 1996/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
Takeda, Tetsuaki; Takenaka, Satsuki*; Hishida, Makoto;
Nihon Genshiryoku Gakkai-Shi, 37(10), p.948 - 958, 1995/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
*; Okamoto, Koji*; *; Fumizawa, Motoo
Kashika Joho Gakkai-Shi, 14(SUPPL.1), p.39 - 42, 1994/07
no abstracts in English
*; *; *; *; Fumizawa, Motoo
Kashika Joho Gakkai-Shi, 13(SUPPL.2), p.87 - 90, 1993/10
no abstracts in English
Fujii, Sadao*; *; Igarashi, Minoru*; Fumizawa, Motoo; Kunugi, Tomoaki; Hishida, Makoto
Proc. of the 6th Int. Topical Meeting on Nuclear Reactor Thermal Hydraulics,Vol. 2, p.1498 - 1505, 1993/00
no abstracts in English
Fumizawa, Motoo; Ogawa, Masuro; Hishida, Makoto; Okamoto, Koji*
FLUCOME-91, p.333 - 338, 1991/00
no abstracts in English
Goto, Minoru; Inaba, Yoshitomo; Aihara, Jun; Ueta, Shohei; Tachibana, Yukio
no journal, ,
JAEA has performed the research and development of the SiC matrix fuel, which is an oxidation resistant fuel against an air ingress accident, to establish the fundamental technologies. In this study, a nuclear thermal design was performed for the HTGR with the SiC matrix fuel.
