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Yonomoto, Taisuke; Okubo, Tsutomu; Iwamura, Takamichi; Ishida, Toshihisa
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 8 Pages, 2003/04
An innovative concept of the pressure suppression system having functions of water injection and non-condensable gas confinement is developed for the next generation light water reactors (LWRs). The use of the system is advantageous for the mitigation of effects of the loss-of-coolant accidents (LOCAs) in (1) keeping the containment pressure as low as for the conventional LWRs, (2) injecting water to the containment for cooling the reactor pressure vessel (RPV) and/or flooding a break, and (3) confining the non-condensable gas in the drywell. The gas confinement function makes the system considerably suitable for reactor designs with passive cooling systems utilizing heat exchangers, such as the steam generator (SG) secondary side cooling system for an integral reactor, and the passive containment cooling system (PCCS), because it avoids adverse effects of non-condensable gas on the heat transfer performance during LOCAs. The usefulness of the developed concept is confirmed in the RELAP5/MOD3 code calculation.
Yoritsune, Tsutomu; Ishida, Toshihisa
JAERI-Tech 2003-022, 118 Pages, 2003/03
JAERI-Tech-2003-022.pdf:18.03MB
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
Ishida, Toshihisa; Yoritsune, Tsutomu
Nuclear Engineering and Design, 215(1-2), p.51 - 67, 2002/06
Times Cited Count：110 Percentile：98.41(Nuclear Science & Technology)no abstracts in English
Yoritsune, Tsutomu; Ishida, Toshihisa
JAERI-Research 2001-053, 45 Pages, 2001/12
JAERI-Research-2001-053.pdf:1.77MB
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.
Kobayashi, Takuya; Togawa, Orihiko; Odano, Naoteru; Ishida, Toshihisa
Journal of Nuclear Science and Technology, 38(8), p.658 - 663, 2001/08
Times Cited Count：2 Percentile：19.66(Nuclear Science & Technology)The collective dose to the Japanese population has been estimated from a hypothetical accident of a nuclear submarine if it sinks in an offshore region around Japan. A computer code system DSOCEAN has been used for assessing the collective dose due to radionuclides released to the ocean from a sunken nuclear submarine. The maximum of the estimated collective effective dose equivalent by the annual intake of marine products after radionuclide releases for one year is approximately 0.5% of the annual average dose by the natural radiation that is reported by UNSCEAR.
Ura, Tamaki*; Takamasa, Tomoji*; Nishimura, Hajime*; Aoki, Taro*; Ueno, Michio*; Maeda, Toshio*; Nakamura, Masato*; Shimazu, Shunsuke*; Tokunaga, Sango*; Shibata, Yozo*; et al.
JAERI-Tech 2001-049, 154 Pages, 2001/07
JAERI-Tech-2001-049.pdf:11.24MB
JAERI has studied on design and operation of a nuclear powered submersible research vessel, which will navigate under sea in the Arctic Ocean, as a part of the design study of advanced marine reactors. This report describes operation conditions and an operating system of the vessel those were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated assuming the observation activities in the Arctic Ocean. A submarine transponder system and an on ice communication buoy system were examined as a positioning and communication system supposing the activity under ice. Procedures to secure safety of nuclear powered submersible research vessel were discussed based on the investigation of accidents. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects fto be settled in the next step were clarified.
Kusunoki, Tsuyoshi; Takahashi, Teruo*; Nishimura, Hajime*; Tokunaga, Sango*; Odano, Naoteru; Yoritsune, Tsutomu; Ishida, Toshihisa
JAERI-Tech 2001-045, 68 Pages, 2001/07
JAERI-Tech-2001-045.pdf:5.33MB
A concept of a submersible research vessel navigating in 600 m depth and a compact nuclear reactor were carried out for the expansion of the nuclear power utilization. The mission of the vessel is the research of mechanism of the climate change. Through conditions of the Arctic Ocean and the sea at high latitude have significant impacts on the global environmental change, it is difficult to investigate those areas by ordinary ships because of thick ice or storm. By taking account of the research mission, the basic specifications of the vessel are decided; the total weight is 500 t, the submersible depth is 600 m, the maximum speed is 12 knots (22.2km/h), and the number of crews is 16. Nuclear power has an advantage in supplying large power of electricity in the sea for long period. Based on the requirements, it has been decided that two sets of compact nuclear reactor, SCR, which is light-weighted and of enhanced safety characteristics to supply the total electricity of 500 kW.
Odano, Naoteru; Ishida, Toshihisa; Wada, Koji*; Imai, Hiroshi*
JAERI-Research 2001-039, 59 Pages, 2001/07
JAERI-Research-2001-039.pdf:4.47MB
A very small reactor, SCR (Submersible Compact Reactor), whose thermal output is 1250 kW, is an integral-pressurized type reactor to be used as a power source for a scientific research vessel in medium depth region of the Arctic Ocean. Neutronic study has been carried out for design of the SCR core of which could achieve continuous long-term operation without refueling for 10 years considering 50 % of load factor of the core. In the present study, arrangement of fuel rods, U enrichment of UO fuel rods and reflector materials were surveyed. The U enrichment has been determined to be 9.5 wt% to satisfy design criteria. In the present study Be metal was adopted as a reflector material. 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 confirmed and the evaluated parameters indicated that the determined core specifications in this study satisfied design conditions.
Ishida, Toshihisa; Imayoshi, Sho*; Yoritsune, Tsutomu; Nunokaya, Hiroshi*; Ochiai, Masaaki; Ishizaka, Yuichi*
Journal of Nuclear Science and Technology, 38(7), p.557 - 570, 2001/07
Times Cited Count：18 Percentile：74.85(Nuclear Science & Technology)no abstracts in English
Nunokawa, Hiroshi*; Yoritsune, Tsutomu; Imayoshi, Sho*; Kasahara, Yoshiyuki*; Ochiai, Masaaki; Ishida, Toshihisa
JAERI-Tech 2001-040, 115 Pages, 2001/06
JAERI-Tech-2001-040.pdf:10.18MB
no abstracts in English
Saito, Kazuo*; Ishida, Toshihisa
JAERI-Tech 2001-039, 25 Pages, 2001/06
JAERI-Tech-2001-039.pdf:0.94MB
no abstracts in English
Saito, Kazuo*; Kusunoki, Tsuyoshi; Ishida, Toshihisa
JAERI-Tech 2001-038, 100 Pages, 2001/06
JAERI-Tech-2001-038.pdf:6.02MB
no abstracts in English
Odano, Naoteru; Ishida, Toshihisa
JAERI-Research 2001-004, 36 Pages, 2001/03
JAERI-Research-2001-004.pdf:1.51MB
no abstracts in English
Kusunoki, Tsuyoshi; Odano, Naoteru; Yoritsune, Tsutomu; Ishida, Toshihisa; Hoshi, Tsutao*; Sako, Kiyoshi*
Nuclear Engineering and Design, 201(2-3), p.155 - 175, 2000/10
Times Cited Count：46 Percentile：92.32(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
Odano, Naoteru; Ishida, Toshihisa
Journal of Nuclear Science and Technology, 37(Suppl.1), p.584 - 588, 2000/03
no abstracts in English
Odano, Naoteru; Yamaji, Akio*; Ishida, Toshihisa
Journal of Nuclear Science and Technology, 37(Suppl.1), p.78 - 82, 2000/03
no abstracts in English
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
