Summary report of the 7th Reduced-Moderation Water Reactor Workshop; March 5, 2004, JAERI, Tokai

Akie, Hiroshi; Nabeshima, Kunihiko; Uchikawa, Sadao

JAERI-Conf 2005-009, 153 Pages, 2005/08

JAERI-Conf-2005-009.pdf:14.7MB

As a research on the future innovative water reactor, the development of Reduced-Moderation Water Reactors (RMWRs) has been performed in JAERI. The workshop on RMWRs is aiming at information exchange between JAERI and other organizations, and has been held every year since 1998. The program of the 7th workshop was composed of 5 lectures and an overall discussion time. This report includes the original papers presented at the workshop and summaries of the questions and answers for each lecture as well as of the discussion time. In addition in Appendix, there are included presentation handouts of each lecture.

Investigation of water-vapor two-phase flow characteristics in a tight-lattice core by large-scale numerical simulation, 3; Analysis of liquid film falling down on inclined flat plate

Yoshida, Hiroyuki; Nagayoshi, Takuji*; Ose, Yasuo*; Takase, Kazuyuki; Akimoto, Hajime

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(1), p.25 - 31, 2005/03

https://doi.org/10.3327/taesj2002.4.25

no abstracts in English

3D measurement of void distribution of boiling flow in a tight-lattice rod bundle by neutron tomography

Kureta, Masatoshi; Tamai, Hidesada

Proceedings of 5th International Conference on Multiphase Flow (ICMF 2004) (CD-ROM), 10 Pages, 2004/06

3D void fraction distribution of boiling flow in a tight-lattice 7-rod bundle was measured by neutron radiography 3D computed tomography (neutron tomography) to investigate the flow characteristics in tight-lattice rod bundles and to verify the numerical analysis codes. The test section simulates the fuel rod bundle of the RMWR and consists of 7 heater rods with gap of 1.0mm and with diameter of 12.0mm. In this paper, the neutron tomography system, experiments and comparison of the measured data with a subchannel analysis code, COBRA-TF, are reported. It was found from this experiment that water layer which surrounds the heater rod becomes thick between rods, narrow region, and steam accumulates at the center region among three rods. COBRA-TF code overestimates the void fraction in a tight-lattice bundle compared with the present data.

Visualization and measurement of boiling flow using neutron beam

Kureta, Masatoshi; Hoshi, Yoshiyuki; Yamada, Kazuyuki*; Sakamoto, Kiyotaka*

Nikkei Saiensu, 111 Pages, 2004/01

no abstracts in English

Design of small reduced-moderation water reactor

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.

Development of visualization technique of analysis results on thermal-hysraulics in a fuel bundle using AVS

Takase, Kazuyuki; Masuko, Kenji*; Ose, Yasuo*; Tamai, Hidesada; Kume, Etsuo

Kashika Joho Gakkai-Shi, 23(Suppl.1), p.363 - 364, 2003/07

no abstracts in English

Critical power in axially uniformly-heated tight-lattice rod bundles

Kureta, Masatoshi; Akimoto, Hajime

Nihon Kikai Gakkai Rombunshu, B, 69(682), p.1469 - 1476, 2003/06

https://doi.org/10.1299/kikaib.69.1469

no abstracts in English

Design study on PWR-type reduced-moderation light water core; Investigation of core adopting seed-blanket fuel assemblies

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.

Design study on Reduced-Moderation Water Reactor (RMWR) core for plutonium multiple recycling

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.

Summary of the 5th Workshop on the Reduced Moderation Water Reactor; March 8, 2002, JAERI, Toaki

Nakano, Yoshihiro; Ishikawa, Nobuyuki; Nakatsuka, Toru; Iwamura, Takamichi

JAERI-Conf 2002-012, 219 Pages, 2002/12

JAERI-Conf-2002-012.pdf:17.4MB

no abstracts in English