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Iwamura, Takamichi; Okubo, Tsutomu; Akie, Hiroshi; Kugo, Teruhiko; Yonomoto, Taisuke; Kureta, Masatoshi; Ishikawa, Nobuyuki; Nagaya, Yasunobu; Araya, Fumimasa; Okajima, Shigeaki; et al.
JAERI-Research 2004-008, 383 Pages, 2004/06
JAERI-Research-2004-008.pdf:21.49MB
The present report contains the achievement of "Research and Development on Reduced-Moderation Light Water Reactor with Passive Safety Features", which was performed by Japan Atomic Energy Research Institute (JAERI), Hitachi Ltd., Japan Atomic Power Company and Tokyo Institute of Technology in FY2000-2002 as the innovative and viable nuclear energy technology (IVNET) development project operated by the Institute of Applied Energy (IAE). In the present project, the reduced-moderation water reactor (RMWR) has been developed to ensure sustainable energy supply and to solve the recent problems of nuclear power and nuclear fuel cycle, such as economical competitiveness, effective use of plutonium and reduction of spent fuel storage. The RMWR can attain the favorable characteristics such as high burnup, long operation cycle, multiple recycling of plutonium (Pu) and effective utilization of uranium resources based on accumulated LWR technologies.
Sakaba, Nariaki; Nakazawa, Toshio; Kawasaki, Kozo; Urakami, Masao*; Saishu, Sadanori*
JAERI-Tech 2003-041, 106 Pages, 2003/03
JAERI-Tech-2003-041.pdf:6.58MB
In the second stage of the research and development for a high-temperature helium-leak detection system, the temperature sensor using optical fibres was studied. The sensor detects the helium leakage by the temperature inclease surrounded opitical fibre with or without heat insulator. Moreover, the applicability of high temperature equipments as the HTTR system was studied. With the sensor we detected 5.0-20.0 cm
/s helium leakages within 60 minutes. Also it was possible to detect earlier when the leakage level is at 20.0 cm/s.
Sakaba, Nariaki; Nakazawa, Toshio; Kawasaki, Kozo; Urakami, Masao*; Saishu, Sadanori*
JAERI-Review 2002-041, 86 Pages, 2003/03
JAERI-Review-2002-041.pdf:3.21MB
In High Temperature Gas-cooled Reactors (HTGR), the detection of leakage of helium at an early stage is very important for the safety and stability of operations. Since helium is a colourless gas, it is generally difficult to identify the location and the amount of leakage when very little leakage has occurred. The purpose of this R&D is to develop a helium-leak detection system for the high temperature environment appropriate to the HTTR. This system can shorten the time of detection to several hours from about one week in the current detection time. In addition, it can also identify easily the leak location using the optical fibre network. As the first step in the development, this paper describes the result of surveying leakage events at nuclear facilities inside and outside Japan and current gas leakage detection technology to adapt optical fibre detection technology to HTGRs.
Sakaba, Nariaki; Nakazawa, Toshio; Kawasaki, Kozo; Urakami, Masao*; Saishu, Sadanori*
JAERI-Research 2003-006, 65 Pages, 2003/03
JAERI-Research-2003-006.pdf:2.89MB
In the final third stage of the research and development for a high-temperature helium-leak detection system, the radiation sensor was developed in order to detect very small helium leakage. Applying the radiation sensor, we proposed not only the direct detection method which uses the detection of FP gas in helium, but also the active method which uses the difference in the radiation absorption between helium and air. From obtained data it was found that we can detect 0.2 cm/s leakage within 10 minutes by the active method.
Kondo, Masaya; Nakamura, Hideo; Anoda, Yoshinari; Saishu, Sadanori*; Obata, Hiroyuki*; Shimada, Rumi*; Kawamura, Shinichi*
Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 9 Pages, 2002/00
no abstracts in English
Onuki, Akira; Nakamura, Hideo; Kawamura, Shinichi*; Saishu, Sadanori*
Nihon Kikai Gakkai Netsu Kogaku Koenkai Koen Rombunshu, p.31 - 32, 2001/11
A passive containment cooling system (PCCS) is under planning to use in a next-generation-type BWR for long-term cooling by condensing steam using horizontal heat exchangers. Heat transfer behavior in a secondary water pool is one of important phenomena governing heat removal performance of the PCCS. Boiling and condensation can be supposed under high heat flux regions and the characteristics of the two-phase natural circulation should be evaluated. This study investigated effects of pool size on the characteristics by multi-dimensional two-fluid model code ACE-3D. It was found from the analyses that the pool size gives no significant influences for the characteristics in tube bundle under local-boiling mode.
Yamagishi, Hideshi; Soyama, Kazuhiko; Kakuta, Tsunemi; Ochiai, Masaaki; Iwamura, Takamichi; Saishu, Sadanori*; Urakami, Masao*; Masuda, Naohiro*; Yamauchi, Yuki*; Otani, Junichi*; et al.
JAERI-Tech 2001-053, 19 Pages, 2001/08
JAERI-Tech-2001-053.pdf:2.48MB
no abstracts in English
Onuki, Akira; Nakamura, Hideo; Anoda, Yoshinari; Obata, Hiroyuki*; Saishu, Sadanori*
Proceedings of 9th International Conference on Nuclear Engineering (ICONE-9) (CD-ROM), 10 Pages, 2001/00
A passive containment cooling system (PCCS) is under planning to use in a next-generation-type BWR for long-term cooling by condensing steam using horizontal heat exchangers. Heat transfer behavior in a secondary water pool is one of important phenomena governing heat removal performance of the PCCS. Boiling and condensation can be supposed under high heat flux regions and the two-phase natural circulation might enhance the heat transfer due to an increase of flow rate and a flow agitation. However, some heat transfer tubes might be covered only by steam and the heat transfer is degraded in such region (Steam-blanket effect). This study evaluated the characteristics of the heat transfer behavior in the secondary water pool by multi-dimensional two-fluid model code ACE-3D. It was found from the analyses that no any heat transfer tubes are covered only by steam and the heat transfer is enhanced due to the nucleate boiling and the increase of local liquid flow rate.