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Okubo, Tsutomu; Iwamura, Takamichi; Takeda, Renzo*; Moriya, Kumiaki*; Yamauchi, Toyoaki*; Aritomi, Masanori*
Nihon Kikai Gakkai 2003-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.245 - 246, 2003/08
A design study on a 300MWe class small Reduced-Moderation Water Reactor (RMWR) has been performed, based on the experienced LWR technology. The core can be cooled by the natural circulation and can achieve a conversion ratio of 1.01, a negative void reactivity coefficient, a core average burn-up of 65 GWd/t and a cycle length of 25 months. The system has been simplified as much as possible by introducing the passive safety components, in order to reduce the construction cost per electric power output overcoming “the scale demerit" for a small reactor comparing with the large one. The results show a 1.35 times higher cost than for the ABWR case, but suggest the possible lower cost when the effects such as the mass production are taken into account.
Shimada, Shoichiro*; Kugo, Teruhiko; Okubo, Tsutomu; Iwamura, Takamichi
JAERI-Research 2003-003, 72 Pages, 2003/03
JAERI-Research-2003-003.pdf:3.82MB
As a part of the design study on PWR-type Reduced-Moderation Water Reactors (RMWRs), a light water cooled core with the seed-blanket type fuel assemblies has been investigated. An assembly with seed of 13 layers and blanket of 5 layers was selected by optimization calculations. The core was composed with the 163 assemblies. The following results were obtained by burn-up calculations with the MVP-BURN code; The cycle length is 15 months by 3-batch refueling. The discharge burn-up including the inner blanket is about 25 GWd/t. The conversion ratio is about 1.0. The void reactivity coefficient is about -26.1pcm/%void at BOC and -21.7pcm/%void at EOC. Effects of about 10% of MA or about 2 % of FP on core performances were investigated, and they were confirmred within the design margins. Capability of multi-recycling of plutonium was confirmed, using discharged plutonium for 4 cycles, if fissile plutonium of 15.5wt% is used.
Okubo, Tsutomu; Iwamura, Takamichi; Takeda, Renzo*; Yamauchi, Toyoaki*; Okada, Hiroyuki*
Proceedings of International Conference on Global Environment and Advanced Nuclear Power Plants (GENES4/ANP 2003) (CD-ROM), 8 Pages, 2003/00
A water-cooled reactor concept named Reduced-Moderation Water Reactor is under development for effective fuel utilization through plutonium multiple recycling based on the water-cooled reactor technology. The reactor aims at achievement of a high conversion ratio more than 1.0 with MOX fuel. Especially, the core performances during the Pu multiple recycling have been investigated for the advanced fuel reprocessing schemes with low decontamination factors than the current PUREX process, and are shown to achieve the conversion ratio more than 1.0 and the negative void reactivity coefficient.
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.
Okubo, Tsutomu; Iwamura, Takamichi; Yamamoto, Kazuhiko*; Okada, Hiroyuki*
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.571 - 574, 2002/00
Based on the experienced light water reactor technology, conceptual design studies on advanced water-cooled reactors have been performed. They are named “Reduced-Moderation Water Reactor" (RMWR) with the high conversion ratio more than 1.0 and the negative void reactivity coefficients. Several concepts have been successfully established for them based on the neutronics calculations. Based on these concepts, detailed investigations on such as plutonium multiple recycling and control rod planning have been performed as well as improvement on core performances. Through these detailed core design investigation, the feasibility of those designs has been confirmed step by step.
Iwamura, Takamichi; Okubo, Tsutomu; Yonomoto, Taisuke; Takeda, Renzo*; Moriya, Kumiaki*; Kanno, Minoru*
Proceedings of International Congress on Advanced Nuclear Power Plants (ICAPP) (CD-ROM), 8 Pages, 2002/00
Research and developments of reduced-moderation water reactor (RMWR) have been performed. The RMWR can attain the favorable characteristics such as high burn-up, long operation cycle, multiple recycling of plutonium and effective utilization of uranium resources, based on the matured LWR technologies. MOX fuel assemblies in the tight-lattice fuel rod arrangement are used to reduce the moderation of neutron, and hence, to increase the conversion ratio. The conceptual design has been accomplished for the small 330MWe RMWR core with the discharge burn-up of 60GWd/t and the operation cycle of 24 months, under the natural circulation cooling of the core. A breeding ratio of 1.01 and the negative void reactivity coefficient are simultaneously realized in the design. In the plant system design, the passive safety features are intended to be utilized mainly to improve the economy. At present, a hybrid one under the combination of the passive and the active components, and a fully passive one are proposed. The former has been evaluated to reduce the cost for the reactor components.
Hibi, Koki*; Shimada, Shoichiro*; Okubo, Tsutomu; Iwamura, Takamichi; Wada, Shigeyuki*
Nuclear Engineering and Design, 210(1-3), p.9 - 19, 2001/12
Times Cited Count：25 Percentile：84.32(Nuclear Science & Technology)no abstracts in English
Okubo, Tsutomu; Takeda, Renzo*; Iwamura, Takamichi
JAERI-Research 2001-021, 84 Pages, 2001/03
JAERI-Research-2001-021.pdf:11.26MB
no abstracts in English
Okubo, Tsutomu; Iwamura, Takamichi; Akimoto, Hajime; Araya, Fumimasa; Onuki, Akira; Yamamoto, Kazuhiko*
Dai-7-Kai Doryoku Enerugi Gijutsu Shimpojiumu Koen Rombunshu (00-11), p.250 - 253, 2000/11
no abstracts in English
Shimada, Shoichiro*; Akie, Hiroshi; Suzaki, Takenori; Okubo, Tsutomu; Usui, Shuji*; Shirakawa, Toshihisa*; Iwamura, Takamichi; Kugo, Teruhiko; Ishikawa, Nobuyuki
JAERI-Research 2000-026, 74 Pages, 2000/06
JAERI-Research-2000-026.pdf:4.07MB
no abstracts in English
Iwamura, Takamichi
Genshiryoku eye, 46(1), p.19 - 23, 2000/00
no abstracts in English
Hibi, Koki*; Kugo, Teruhiko; Tochihara, Hiroshi*; Shimada, Shoichiro*; Okubo, Tsutomu; Iwamura, Takamichi; Wada, Shigeyuki*
Proceedings of 8th International Conference on Nuclear Engineering (ICONE-8) (CD-ROM), p.11 - 0, 2000/00
no abstracts in English
Okubo, Tsutomu; Shirakawa, Toshihisa*; Takeda, Renzo*; Yokoyama, Tsugio*; Iwamura, Takamichi; Wada, Shigeyuki*
Proceedings of 8th International Conference on Nuclear Engineering (ICONE-8) (CD-ROM), p.7 - 0, 2000/00
no abstracts in English
; Nakajima, Ken; Yanagisawa, Hiroshi; ; ; *; *; Sakuraba, Koichi; Ono, Akio
Proceedings of 6th International Conference on Nuclear Criticality Safety (ICNC '99), 3, p.1277 - 1285, 1999/00
no abstracts in English
