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Ho, H. Q.; Honda, Yuki; Motoyama, Mizuki*; Hamamoto, Shimpei; Ishii, Toshiaki; Ishitsuka, Etsuo
Applied Radiation and Isotopes, 135, p.12 - 18, 2018/05
Times Cited Count：7 Percentile：57.59(Chemistry, Inorganic & Nuclear)Uchikawa, Sadao; Okubo, Tsutomu; Kugo, Teruhiko; Akie, Hiroshi; Nakano, Yoshihiro; Onuki, Akira; Iwamura, Takamichi
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
no abstracts in English
Onuki, Akira; Takase, Kazuyuki; Kureta, Masatoshi*; Yoshida, Hiroyuki; Tamai, Hidesada; Liu, W.; Nakatsuka, Toru; Misawa, Takeharu; Akimoto, Hajime
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
R&D project to investigate thermal-hydraulic performance in tight-lattice rod bundles for Reduced-Moderation Water Reactor (RMWR) is started at Japan Atomic Energy Research Institute in collaboration with power company, reactor vendors, universities since 2002. The RMWR can attain the favorable characteristics such as effective utilization of uranium resources, multiple recycling of plutonium, high burn-up and long operation cycle, based on matured LWR technologies. The confirmation of thermal-hydraulic feasibility is one of the most important R&D items for the RMWR because of the tight-lattice configuration. In this paper, we will show the R&D plan and describe some advances on experimental and analytical studies. Steady-state and transient critical power experiments have been conducted with two 37-rod bundle test facilities (Gap width between rods: 1.3mm and 1.0mm) and the experimental data reveal the feasibility of RMWR.
Iwamura, Takamichi; Uchikawa, Sadao; Okubo, Tsutomu; Kugo, Teruhiko; Akie, Hiroshi; Nakatsuka, Toru
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 8 Pages, 2005/05
In order to ensure sustainable energy supply in the future based on the matured Light Water Reactor (LWR) and coming LWR-Mixed Oxide (MOX) technologies, a concept of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been investigated in Japan Atomic Energy Research Institute (JAERI). The concept consists of two parts in the chronological sequence. The first part realizes a high conversion type core concept, which is basically intended to keep the smooth technical continuity from current LWR without significant gaps in technical point of view. The second part represents the Reduced-Moderation Water Reactor (RMWR) core concept, which realizes a high conversion ratio over 1.0 being useful for the long-term sustainable energy supply through plutonium multiple recycling based on the well-experienced LWR technologies. The key point is that the two core concepts utilize the compatible and the same size fuel assemblies, and hence, the former concept can proceed to the latter in the same reactor system, based flexibly on the fuel cycle circumstances.
Onuki, Akira; Takase, Kazuyuki; Kureta, Masatoshi*; Yoshida, Hiroyuki; Tamai, Hidesada; Liu, W.; Nakatsuka, Toru; Akimoto, Hajime
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 8 Pages, 2005/05
R&D project to investigate thermal-hydraulic performance in tight-lattice rod bundles for Reduced-Moderation Water Reactor (RMWR) is started at Japan Atomic Energy Research Institute in collaboration with power company, reactor vendors, universities since 2002. The RMWR can attain the favorable characteristics such as effective utilization of uranium resources, multiple recycling of plutonium, high burn-up and long operation cycle, based on matured LWR technologies. The confirmation of thermal-hydraulic feasibility is one of the most important R&D items for the RMWR because of the tight-lattice configuration. In this paper, we will show the R&D plan and describe some advances on experimental and analytical studies. The experimental study is performed mainly using large-scale (37-rod bundle) test facility and the analytical one aims to develop a predictable technology for geometry effects such as gap between rods etc. using advanced 3-D two-phase flow simulation methods. Steady-state and transient critical power experiments are conducted with the test facility (Gap width between rods: 1.3mm and 1.0mm) and the experimental data reveal the feasibility of RMWR.
Onuki, Akira; Takase, Kazuyuki; Kureta, Masatoshi; Yoshida, Hiroyuki; Tamai, Hidesada; Liu, W.; Akimoto, Hajime
Proceedings of 2004 International Congress on Advances in Nuclear Power Plants (ICAPP '04), p.1488 - 1494, 2004/06
We start R&D project to develop the predictable technology for thermal-hydraulic performance of Reduced-Moderation Water Reactor (RMWR) in collaboration with power company/reactor vendor/university since 2002. The RMWR can attain the favorable characteristics such as effective utilization of uranium resources based on matured BWR technologies. MOX fuel assemblies with tight lattice arrangement are used to increase the conversion ratio by reducing the moderation of neutron energy. Increasing the in-core void fraction also contributes to the reduction of neutron moderation. The confirmation of thermal-hydraulic feasibility is one of the most important R&D items for the RMWR. This series presentation focuses on the feasibility study and shows the R&D plan using large-scale test facility and advanced numerical simulation technology.
Sato, Tatsuhiko; Tsuda, Shuichi; Sakamoto, Yukio; Yamaguchi, Yasuhiro; Niita, Koji*
Radiation Protection Dosimetry, 106(2), p.137 - 144, 2003/11
Times Cited Count：19 Percentile：75.71(Environmental Sciences)Radiological protection against high energy heavy ions has been an essential issue in the planning of long-term space missions. We calculated fluence to effective dose conversion coefficients for heavy ions using the Particle and Heavy Ion Transport code System PHITS coupled with an anthropomorphic phantom of the MIRD5 type. The calculations were performed for incidences of protons and typical space heavy ions with energies up to 3 GeV/A in the isotropic and anterior-posterior irradiations. Based on the results, we propose a simple fitting formula that can predict the effective dose from almost all kinds of space heavy ions below 3 GeV/A within an accuracy of 30%.
Okubo, Tsutomu
Konsoryu, 17(3), p.228 - 235, 2003/09
The Reduced-Moderation Water Reactor is supposed to realize plutonium multiple recycling, and furthermore, plutonium breeding cycle, based on the well-established Light Water Reactor technologies. In the present paper, the overview of the design study is presented and the related R&D issues are introduced, especially focusing on the thermal hydraulic activities.
Iwamura, Takamichi; Okubo, Tsutomu
Proceedings of 2nd Asian Specialist Meeting on Future Small-Sized LWR Development, p.7_1 - 7_5, 2003/00
An innovative water-cooled reactor concept named Reduced-Moderation Water Reactor (RMWR) is under development at JAERI, aiming at effective fuel utilization through plutonium (Pu) multiple recycling based on the well-experienced water-cooled reactor technology. The reactor is able to achieve a high conversion ratio more than 1.0 with MOX fuel, to establish the sustainable Pu recycling. Such a high conversion ratio can be attained by reducing the moderation of neutrons, i.e. reducing the water fraction in the core. Detailed research and development activities have been performed on the core design, in conjunction with the other related studies such as on the thermal hydraulics in the tight-lattice core, the reactor physics and the fuel irradiation behavior, including the experimental activities. Also, for the total feasibility demonstration of the RMWR technologies, a design investigation for Reduced-Moderation Demonstration Reactor (RMDR) of 180MWt is being performed.
Iwamura, Takamichi; Okubo, Tsutomu; Kureta, Masatoshi; Nakatsuka, Toru; Takeda, Renzo*; Yamamoto, Kazuhiko*
Proceedings of 13th Pacific Basin Nuclear Conference (PBNC 2002) (CD-ROM), 7 Pages, 2002/10
In order to ensure sustainable energy supply in Japan, the reduced-moderation water reactor (RMWR) has been developed by JAERI since 1998. MOX fuel assemblies with tight lattice arrangement are used to increase the conversion ratio. In order to establish negative void reactivity coefficient, the core should be short and flat to increase neutron leakage from the core. The core designs were accomplished to a large core with 1,356MWe and a small core with 330MWe. For both cores, negative void coefficient and natural circulation cooling of the core were realized. To confirm thermal-hydraulic feasibility, critical heat flux experiments were performed using 7-rod bundles with the gap width of 1mm and 1.3mm. The results indicated that enough cooling was assured for the tight lattice core. Further R&D studies, including large scale thermal-hydraulic experiments, reactor physics experiments, development of high burn-up fuel cladding material and simplified reprocessing technology, are necessary to realize commercial introduction of RMWR by 2020's for the replacement of current generation LWRs.
Sasamoto, Nobuo; Nakashima, Hiroshi; Hirayama, Hideo*; Shibata, Tokushi*
Journal of Nuclear Science and Technology, 39(Suppl.2), p.1264 - 1267, 2002/08
no abstracts in English
Okubo, Tsutomu; Takeda, Renzo*; Iwamura, Takamichi; Yamamoto, Kazuhiko*; Okada, Hiroyuki*
Proceedings of International Conference on Back-End of the Fuel Cycle: From Research to Solutions (GLOBAL 2001) (CD-ROM), 7 Pages, 2001/09
An advanced water-cooled reactor concept named the Reduced-Moderation Water Reactor (RMWR) has been proposed to attain a high conversion ratio more than 1.0 and to achieve the negative void reactivity coefficient. At present, several types of design concepts satisfying both the design targets have been proposed based on the evaluation for the fuel without fission products and minor actinides. In this paper, the feasibility of the RMWR core is investigated and confirmed for the plutonium multiple recycling under advanced reprocessing schemes with low decontamination factors as proposed for the FBR fuel cycle.
Ando, Masaki; *; Nishina, Kojiro*; *
Journal of Nuclear Science and Technology, 34(5), p.445 - 453, 1997/05
Times Cited Count：6 Percentile：47.9(Nuclear Science & Technology)no abstracts in English
*; Furihata, Shiori*; Uehara, Takashi*; Yoshizawa, Nobuaki*; Iwai, Satoshi*; Tanaka, Shunichi; Sakamoto, Yukio
JAERI-M 93-147, 90 Pages, 1993/07
no abstracts in English
Nakakawa, Masayuki; Fujii, Sadao*; *; *
Journal of Nuclear Science and Technology, 29(11), p.1116 - 1119, 1992/11
no abstracts in English
*; Uehara, Takashi*; *; Iwai, Satoshi*; Tanaka, Shunichi
JAERI-M 92-126, 88 Pages, 1992/09
no abstracts in English
*; Okumura, Keisuke;
JAERI-M 92-067, 35 Pages, 1992/05
no abstracts in English
-UO fuel assemblyC-S.Gil*; Okumura, Keisuke;
JAERI-M 91-200, 61 Pages, 1991/11
no abstracts in English
Okajima, Shigeaki; Osugi, Toshitaka; Sakurai, Takeshi; *
Journal of Nuclear Science and Technology, 27(10), p.950 - 959, 1990/10
no abstracts in English
Okumura, Keisuke; ; Mori, Takamasa; Nakakawa, Masayuki;
JAERI-M 90-096, 169 Pages, 1990/06
no abstracts in English
