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Takano, Kazuya; Oki, Shigeo; Doda, Norihiro; Chikazawa, Yoshitaka; Maeda, Seiichiro
Proceedings of 2023 International Congress on Advanced in Nuclear Power Plants (ICAPP 2023) (Internet), 7 Pages, 2023/04
The MOX fueled SMR-SFRs with lower linear heat rating of 100 W/cm and 50 W/cm, whereas the linear heat rating at rated power is around 400 W/cm in general, were designed to decrease the fuel temperature during its rated power state in order to pursue the inherent core safety for MOX fueled SMR-SFRs. The transient analyses for Anticipated Transient Without Scram (ATWS) events represented by an Unprotected Loss of Flow (ULOF) accident on the lower linear heat rating cores were performed considering their inherent feedback reactivity. Through the transient analysis, the inherent core safety performances for the lower linear heat rating cores were discussed based on the evaluated maximum coolant temperature and Cumulative Damage Fraction (CDF) as criteria to maintain the core and fuel integrity. The feasible design window for MOX fueled SMR-SFRs with the inherent core safety focusing on the linear heat rating was identified based on the transient analysis results.
Takata, Takashi; Aoyagi, Mitsuhiro; Sonehara, Masateru
IAEA-TECDOC-1972, p.224 - 234, 2021/08
Sodium fire is one of the key issues for plant safety of sodium-cooled fast reactor (SFR) regardless of its size. In general, a concrete structure, which includes free and bonging water inside, is used in a reactor building. Accordingly, water vapor will release from the concrete during sodium fire incident due to temperature increase resulting in a hydrogengeneration even in a dry air condition. The probability of hydrogen generation will increase in accordance with a decrease of a dimension of compartment that corresponds to a small and medium sized or modular reactor (SMR). A numerical investigation of a small leakage sodium pool fire has been carried out by changing a dimension of compartment. Furthermore, numerical challenges to enhance a prediction accuracy of hydrogen generation during sodium fire has also been discussed in the paper.
Nakajima, Nobuya; Takahashi, Hiroki; Kusunoki, Tsuyoshi; Mitomo, Nobuo
JAERI-Tech 2005-057, 54 Pages, 2005/09
JAERI-Tech-2005-057.pdf:4.27MB
Availability using small reactor sited in deep underground cave was examined as a district heat supply system.From the viewpoint of a social acceptability, the contact points with a distributed small reactor system were examined to resolve a social structure-subject of a big city through investigation of the city environmental issue and city calamity. In order to estimate the scale of the heat source of a district heat supply system, a virtual city model was set up about 100,000 populations. It became clear that the heat can be supplied by installing two reactors with thermal-power 100MWt (MR-100G) in caves. Moreover, it turns out that the system will also function effectively for more than 40 years. The economic efficiency of this system was compared with the natural-gas boiler, and we confirmed that the district heat supply system by the small reactor is excellent especially for the case of long-term system operation.
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.
Yoritsune, Tsutomu; Ishida, Toshihisa
JAERI-Tech 2003-022, 118 Pages, 2003/03
JAERI-Tech-2003-022.pdf:18.03MB
no abstracts in English
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
Yoritsune, Tsutomu; Ishida, Toshihisa; Imayoshi, Sho*
Journal of Nuclear Science and Technology, 39(8), p.913 - 922, 2002/08
Times Cited Count：4 Percentile：29.25(Nuclear Science & Technology)no abstracts in English
Ochiai, Masaaki
Nihon Genshiryoku Gakkai-Shi, 43(11), p.1070 - 1074, 2001/11
no abstracts in English
Odano, Naoteru; Ishida, Toshihisa; Ochiai, Masaaki
JAERI-Research 2001-044, 53 Pages, 2001/10
JAERI-Research-2001-044.pdf:2.35MB
A very small reactor, MR-1G with a thermal output of 1 MW, is the integral-pressurized type reactor to be used for heat supply to an office building in a city. Neutronic study has been carried out for design of the MR-1G, the core of which could achieve continuous long-term operation without refueling for 10 years assuming a load factor of the core of 44 %. In the present study, arrangement of fuel rods and 
U enrichment of UO
fuel rods were surveyed as design parameters. The U enrichment was determined to be 8.5 wt% to satisfy design requirement. Reactor physics parameters including reactivity coefficients and power distributions were evaluated for the determined core specifications. Reactor physics parameters related to core safety were also analyzed. Results of the safety analysis indicated that the determined core specifications satisfied design conditions. Reactor shutdown performance by dropping the reflector, which was adopted as a passive reactor shutdown system, was analyzed and confirmed it's availability from a viewpoint of reactor physics.
Odano, Naoteru; Ishida, Toshihisa
JAERI-Research 2001-004, 36 Pages, 2001/03
JAERI-Research-2001-004.pdf:1.51MB
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.
Kusunoki, Tsuyoshi; Odano, Naoteru; Nakajima, Nobuya; Fukuhara, Yoshifumi*; Ochiai, Masaaki
Nihon Genshiryoku Gakkai-Shi, 42(11), p.1195 - 1203, 2000/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
Kusunoki, Tsuyoshi; Fujimoto, Hiromi*; Nagata, Yutaka*; Takahashi, Teruo*; Ishida, Toshihisa
Kaiyo Chosa Gijutsu, 12(2), p.1 - 10, 2000/09
no abstracts in English
; Kawasaki, Nobuchika; ; *; ; ;
JNC TN9400 2000-063, 221 Pages, 2000/06
JNC-TN9400-2000-063.pdf:8.68MB
ln this paper, feasibility of the multipurpose small fast reactor, which could be used for requirements concemed with various utilization of electricity and energy and flexibility of power supply site, is discussed on the basis of examination of literatures of various small reactors. And also, a possibility of economic improvement by learning effect of fabrication cost is discussed for the modular-sized reactor which is expected to be a base load power supply system with lower initial investment. (1) Multipurpose small reactor (a) The small reactor with 10MWe
150MWe has a potential as a power source for large co-generation, a large island, a middle city, desalination and marine use. (b) Highly passive mechanism, long fuel exchange interval, and minimized maintenance activities are required for the multipurpose small reactor design. The reactor has a high potential for the long fuel exchange interval, since it is relatively easy for FR to obtain a long life core. (c) Current designs of small FRs in Japan and USA (NERI Project) are reviewed to obtain design requirements for the multipurpose small reactor. (2) Modular-sized reactor (a) ln order that modular-sized reactor could be competitive to 3200MWe twin plant (two large monolithic reactor) with 200k/kWe, the target capital cost of FOAK is estimated to be 260k/kWe for 800MWe modular, 280k/kWe for 400MWe modular and 290k/kWe for 200MWe by taking account of the learning effect. (b)As the result of the review on the current designs of modular-sized FRs in Japan and USA (S-PRISM) from the viewpoint of economic improvement, since it only be necessary to make further effort for the target capital cost of FOAK, since the modular-sized FRs requires a large amount of material for shielding, vessels and heat exchangers essentially.
Odano, Naoteru; Kusunoki, Tsuyoshi; Yoritsune, Tsutomu; Fukuhara, Yoshifumi*; Saito, Kazuo*; Takahashi, Teruo*; Ishida, Toshihisa
Proceedings of International Workshop on Utilization of Nuclear Power in Oceans (N'ocean 2000), p.164 - 169, 2000/02
no abstracts in English
Iwamura, Takamichi; Minato, Kazuo
Nihon Genshiryoku Gakkai-Shi, 42(1), p.25 - 27, 2000/01
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
Fune No Kagaku, 51(1), p.68 - 74, 1998/01
no abstracts in English
JAERI-Tech 97-045, 601 Pages, 1997/10
no abstracts in English
