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Okubo, Tsutomu; Suzuki, Motoe; Iwamura, Takamichi; Takeda, Renzo*; Moriya, Kumiaki*; Kanno, Minoru*
Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 10 Pages, 2002/10
A small scale around 300 MWe reduced-moderation water reactor (RMWR) concept has been developed. For the core, a BWR type core concept with the tight-lattice fuel rod arrangement and the high void fraction is adopted to attain a high conversion ratio over 1.0. The negative void reactivity coefficients are also required, and the very flat short core concept is adopted to make the natural circulation cooling (NC) possible. The core burn-up of 60 GWd/t and the operation cycle of 24 months are also attained. For the system, simplification of the system with the passive safety features is a basic approach to overcome the scale demerit as well as the NC. For example, the HPCF system is replaced with the passive accumulator system resulting in the expensive emergency DGs reduction. The cost evaluation for concerned NSSS components gives about 20% reduction. Since MOX fuels in the RMWR contains Pu around 30 wt% and is irradiated to a high burn-up, the fuel safety evaluation has been performed and the acceptable results have been obtained from the thermal feasibility point of view.
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
Ochiai, Masaaki
Nihon Genshiryoku Gakkai-Shi, 43(11), p.1070 - 1074, 2001/11
no abstracts in English
Iwamura, Takamichi; Ochiai, Masaaki
Proceedings of 1st Asian Specialist Meeting of Future Small-Sized LWR Development, p.7_1 - 7_9, 2001/00
JAERI has developed two types of small and medium size Light Water Reactors to meet the goals of innovative nuclear reactors such as sustainability and diversification of energy utilization. One is the Reduced-Moderation light Water Reactor (RMWR) with passive safety features. The reactor core consists of MOX fuel assemblies with tight lattice arrangement to increase the conversion ratio by reducing the moderation of neutron energy. The core design of 330MWe output with the operational cycle of 26 months was accomplished. A breeding ratio of 1.01, negative void coefficient and natural circulation cooling of the core were realized under the discharged burn-up of 60GWd/t. The other is the Passive Safe small Reactor for Distributed energy systems (PSRD) to diversify the nuclear energy utilization. An innovative advanced marine reactor (MRX) is used to supply the small grid electricity or electricity and heat co-supply by installing it on a barge. A small integral LWR for underground deployment is also studied for exclusive use of heat supply to household or office.
JNC TN1400 2000-012, 250 Pages, 2000/11
JNC-TN1400-2000-012.pdf:10.18MB
no abstracts in English
Kusunoki, Tsuyoshi; Odano, Naoteru; Yoritsune, Tsutomu; Fukuhara, Yoshifumi*; Nakajima, Nobuya; Ochiai, Masaaki
Proceedings of the 4th JSME-KSME Thermal Engineering Conference, p.1_61 - 1_66, 2000/00
no abstracts in English
Hayashi, Hideyuki; ;
PNC TN9410 96-062, 186 Pages, 1996/02
A conceptual design study on a 1300MWe large FBR plant was performed with focusing on enhancing passive safety and capital cost reduction. Spectrum-adjusted mixed nitride fueled core in which zirconium hydride was added, was applied to enlarge Doppler reactivity coefficient. Breeding ratio of 1.2 was obtained only with one layer of radial blanket subassemblies by optimizing the content of the zirconium hydride. The optimization also lightened the burden to the reactor structure through the reduction of the core diameter. Reactor passive shutdown were performed in the ATWS events of ULOF and ULOHS, and UTOP caused by one control rod full runout was endurable under the criterion of the prevention of coolant boiling. The safety feature can be called as inherent safety, because the feature comes only from the reactivity characteristics of the core. The integrities of the reactor structures which characterize head-access loop type reactor were evaluated on the transient thermal stress at the loss of flow accident and on seismic strain. Vertical strain of core support plate at loss of flow condition was also evaluated on the passive shutdown at ULOF. The capital cost of the large FBR plant was estimated 1.3 to 1.4 times as high as that of the same scale LWR based on the weight of major components.
*; Akino, Norio; *; *; *; *; Takeda, Tetsuaki; *
Journal of Nuclear Science and Technology, 30(2), p.131 - 142, 1993/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
*; *; *; *; *; Akino, Norio; Takeda, Tetsuaki; *
Proc. of the 1st JSME/ASME Joint Int. Conf. on Nuclear Engineering,Vol. 1, p.101 - 107, 1991/00
no abstracts in English
Sekio, Yoshihiro; Sato, Isamu*; Kawashima, Masatoshi*; Morita, Koji*
no journal, ,
A proposed passive reactor shutdown device contains pins with fuels that are kept in the solid state during normal operation but melt into the liquid when its temperature exceeds a prescribed value under severe accidents. The device leads reactor to subcritical state by liquid fuel migration to low positions in the pins. In this study, the device structure for fast reactor core was proposed based on safety evaluation results. The liquid fuel is needed to migrate before the accident occurs, and the migration time would depend on the fuel viscosity. To obtain basic acknowledge for determination of fuel chemical components, the effect of material viscosities on fuel migration time was evaluated through visualization experiments using liquid samples with different viscosities.
Sekio, Yoshihiro; Sato, Isamu*; Kawashima, Masatoshi*; Morita, Koji*
no journal, ,
A proposed passive reactor shutdown device contains pins with fuels that are kept in the solid state during normal operation but melt into the liquid when its temperature exceeds a prescribed value under severe accidents. The device leads reactor to subcritical state by liquid fuel migration to low positions in the pins. In this study, for the purpose of obtaining basic knowledge for evaluating the engineering feasibility of the proposed device structure, we made a simulated device pin using a simulated solid fuel, a thin pipe and so on. The melting and migrating behaviors of the solid fuel in the pin were evaluated through visualization experiments.
Futagami, Satoshi; Ando, Masanori; Yamano, Hidemasa; Kasahara, Naoto*
no journal, ,
To improve resilience of next-generation nuclear power plants, the authors have performed structural analyses assuming a protected loss of heat sink event, which may cause all decay heat removal systems to lose their functions immediately after reactor shutdown. From the results of these analysis, the authors developed a passive safety structure under extremely high temperatures.
