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Journal Articles

Development of simple method to incorporate out-of-core cooling effect on thorium conversion in multi-pass fueled reactor and investigation on characteristics of the effect

Fukaya, Yuji

Annals of Nuclear Energy, 81, p.301 - 305, 2015/07

 Times Cited Count:1 Percentile:10.86(Nuclear Science & Technology)

Development of a simple method to incorporate the out-of-core cooling effect on the thorium conversion in multi-pass fueled reactors and investigation on characteristics of the effect have been performed. For multi-pass fueled reactors, such as Molten Salt Breeder Reactor (MSBR) and Pebble-Bed Modular Reactor (PBMR), fuel moves in the core and exits from the core. The nuclides decay also out of the core, and it should be also considered if it is important for core characteristics. In the present study, $$^{233}$$Pa is considered to evaluate the thorium conversion accurately. To take the effect into account, in the present study, an effective decay constant is proposed to make equilibrium concentration of $$^{233}$$Pa without out-of-core cooling equal to that of out-of-core cooling. With the effective decay constant, the out-of-core cooling effect can be incorporated even with the code system using macroscopic cross sections generated by cell burn-up calculations without any code modification. In addition, the characteristic of out-of-core cooling effect for the thorium conversion is evaluated for thorium fueled reactors of MSBR and PBMR. It is concluded that the out-of-core cooling effect is suitable for MSBR to enhance thorium conversion because of the fast flow rate of fuel salt. On the other hand, the effect is not important and not realistic to employ for PBMR because the in-core residence time of approximately 100 days is longer than the half-life of $$^{233}$$Pa of 27.0 days, and the effect cannot improve the conversion ratio drastically.

Journal Articles

Master plan and current status for feasibility study on thermal/hydraulic performance of reduced-moderation water reactor

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.

Journal Articles

Advances of study on thermal/hydraulic performance in tight-lattice rod bundles for reduced-moderation water reactors

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.

Journal Articles

Development of predictable technology for thermal/hydraulic performance of reduced-moderation water reactors, 1; Master Plan

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.

Journal Articles

Designing of reduced-moderation water reactor and related development issues

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.

Journal Articles

Research and development of Reduced-Moderation Water Reactor (RMWR)

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.

Journal Articles

Development of Reduced-Moderation Water Reactor (RMWR) for sustainable energy supply

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.

JAEA Reports

Research on reduced-moderation water reactor (RMWR)

Iwamura, Takamichi; Okubo, Tsutomu; Shimada, Shoichiro*; Usui, Shuji*; Shirakawa, Toshihisa*; Nakatsuka, Toru; Kugo, Teruhiko; Akie, Hiroshi; Nakano, Yoshihiro; Wada, Shigeyuki*

JAERI-Research 99-058, p.61 - 0, 1999/11

JAERI-Research-99-058.pdf:3.3MB

no abstracts in English

Journal Articles

Conversion of JRR-4 fuel to LEU

Watanabe, Shukichi; Nakajima, Teruo; Kaieda, Keisuke

JAERI-Conf 99-006, p.119 - 124, 1999/08

no abstracts in English

Journal Articles

Status of JRR-4 modification works

Nakajima, Teruo; Bamba, Masao; ; ; Horiguchi, Yoji; Kaieda, Keisuke

Proc. of 6th Meeting of the Int. Group on Research Reactors, p.51 - 56, 1998/00

no abstracts in English

Journal Articles

Measurement of flux tilt and eigenvalue separation in axially decoupled core

Ando, Masaki; *; Nishina, Kojiro*; *

Journal of Nuclear Science and Technology, 34(5), p.445 - 453, 1997/05

 Times Cited Count:6 Percentile:48.7(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Journal Articles

Experimental study on reactivity worth for absorber material in high conversion light water reactor using FCA-HCLWR core fueled with enriched uranium

Okajima, Shigeaki; Osugi, Toshitaka; Sakurai, Takeshi; *

Journal of Nuclear Science and Technology, 27(10), p.950 - 959, 1990/10

no abstracts in English

JAEA Reports

Conceptual design study of high conversion light water reactor

Okumura, Keisuke; ; Mori, Takamasa; Nakakawa, Masayuki;

JAERI-M 90-096, 169 Pages, 1990/06

JAERI-M-90-096.pdf:5.02MB

no abstracts in English

JAEA Reports

Measurement of reaction rates in FCA XIV-cores simulating high conversion light water reactor

Obu, Makoto; ; Sakurai, Takeshi; Iijima, Susumu; *; Osugi, Toshitaka

JAERI-M 90-052, 52 Pages, 1990/03

JAERI-M-90-052.pdf:1.31MB

no abstracts in English

JAEA Reports

Thermal-Hydrauluc Analysis of Loss-of-Coolant Accident in the JMTR

;

JAERI-M 85-001, 33 Pages, 1985/02

JAERI-M-85-001.pdf:0.74MB

no abstracts in English

JAEA Reports

Computed results on the IAEA benchmark problems at JAERI

; *; ;

JAERI-M 9174, 78 Pages, 1980/11

JAERI-M-9174.pdf:2.23MB

no abstracts in English

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