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Nemoto, Takahiro; Arakawa, Ryoki; Kawakami, Satoru; Nagasumi, Satoru; Yokoyama, Keisuke; Watanabe, Masashi; Onishi, Takashi; Kawamoto, Taiki; Furusawa, Takayuki; Inoi, Hiroyuki; et al.
JAEA-Technology 2023-005, 33 Pages, 2023/05
JAEA-Technology-2023-005.pdf:5.25MB
During shut down of the HTTR (High Temperature engineering Test Reactor) RS-14 cycle, an increasing trend of filter differential pressure for the helium gas circulator was observed. In order to investigate this phenomenon, the blower of the primary helium purification system was disassembled and inspected. As a result, it is clear that the silicon oil mist entered into the primary coolant due to the deterioration of the charcoal filter performance. The replacement and further investigation of the filter are planning to prevent the reoccurrence of the same phenomenon in the future.
Sakaba, Nariaki; Nakagawa, Shigeaki; Furusawa, Takayuki; Tachibana, Yukio
JAERI-Tech 2004-045, 67 Pages, 2004/04
JAERI-Tech-2004-045.pdf:4.74MB
Safety demonstration tests using the HTTR are now underway in order to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to research and development for the VHTR, which is one of the Generation IV reactors. In the safety demonstration tests, the coolant flow reduction test by tripping one or two out of three gas circulators is being performed between FY2002 and FY 2005 and by tripping all the three gas circulators will be conducted after FY2006. This paper describes the structural integrity assessment of the primary pressurised water cooler after one and two gas circulators run down. Also, the possibility of natural convection in the primary coolant after all the three gas circulator stopped was evaluated by the operation data of the reactor-scram test performed during the rise-to-power tests.
Furusawa, Takayuki; Sumita, Junya; Ueta, Shohei; Nemoto, Takahiro; Oyama, Sunao*; Kamata, Takashi
JAERI-Tech 2004-024, 46 Pages, 2004/03
JAERI-Tech-2004-024.pdf:6.75MB
Primary helium circulators of the HTTR are the important component as the helium gas which is reactor coolant, and three circulators for the primary pressurized water cooler and one for the intermediate heat exchanger are installed in primary cooling system. In the upstream of these circulators, the filter has been installed in order to suppress that it is entrapped in the bearing in which fine particles in helium gas, support main shaft of the helium circulator. The differential pressure of this filter rose gradually during rise-to-power test. The rise of the filter differential pressure of the helium circulator may cause the problem for reactor operation. Therefore, the filters were newly manufactured, and replacement of the filter was carried out. In replacement of the filter, appearance confirmation was carried out and deposit of the filter was analyzed. This paper described replacement of the filter and filter differential pressure rise investigation of the causes.
Sakaba, Nariaki; Nakagawa, Shigeaki; Takamatsu, Kuniyoshi; Takada, Eiji*; Saito, Kenji; Furusawa, Takayuki; Tochio, Daisuke; Tachibana, Yukio; Iyoku, Tatsuo
JAERI-Tech 2004-014, 24 Pages, 2004/02
JAERI-Tech-2004-014.pdf:1.06MB
Safety demonstration tests using the HTTR are in progress to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to not only the commercial HTGRs but also the research and development for the VHTR one of the Generation IV reactors. This paper describes the reactivity insertion test and coolant flow reduction test by trip of gas circulator and partial flow loss of coolant planned in 2004 with detailed test method, procedure and results of pre-test analysis. From the analytical results, it was found that the negative reactivity feedback effect of the core brings the reactor power safely to a stable level without a reactor scram.
Sakaba, Nariaki; Nakagawa, Shigeaki; Takada, Eiji*; Tachibana, Yukio; Saito, Kenji; Furusawa, Takayuki; Takamatsu, Kuniyoshi; Tochio, Daisuke; Iyoku, Tatsuo
JAERI-Tech 2003-074, 37 Pages, 2003/08
JAERI-Tech-2003-074.pdf:1.83MB
Safety demonstration tests using HTTR are now underway in order to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to research and development for the VHTR, which is one of the Generation IV reactors. The first phase of the safety demonstration tests includes reactivity insertion tests by means of control-rod withdrawal and coolant flow reduction tests by tripping the gas circulators. In the second phase, accident simulation tests will be conducted. This paper describes the plan of coolant flow reduction tests by tripping of gas circulators planned in August 2003 with detailed test method, procedure and results of pre-test analysis. The analysis results of the steady state and transient behaviours of the reactor and the plant of the HTTR show that in the case of a rapid decrease of the coolant flow rate, the negative reactivity feedback effect of the core brings the reactor power safely to certain stable level without a reactor scram, and that the temperature transient of the reactor core is slow.
Nakagawa, Shigeaki; Sakaba, Nariaki; Takada, Eiji*; Tachibana, Yukio; Saito, Kenji; Furusawa, Takayuki; Sawa, Kazuhiro
JAERI-Tech 2003-049, 22 Pages, 2003/03
JAERI-Tech-2003-049.pdf:1.17MB
Safety demonstration tests in the HTTR (High Temperature Engineering Test Reactor) will be carried out in order to verify inherent safety features of the HTGR (High Temperature Gas-cooled Reactor). The first phase of the safety demonstration tests includes the reactivity insertion test by the control rod withdrawal and the coolant flow reduction test by the gas circulator trip. In the second phase, accident simulation tests will be conducted. By comparison of their experimental and analytical results, the prediction capability of the safety evaluation codes such as the core and the plant dynamics codes will be improved and verified, which will contribute to establish the safety design and the safety evaluation technologies of the HTGRs. The results obtained through its safety demonstration tests will be also utilised for the establishment of the safety design guideline, the safety evaluation guideline, etc. This paper describes the test program of the overall safety demonstration tests and the test method, the test conditions and the results of the pre-test analysis of the reactivity insertion test and the partial gas circulator trip test planned in March 2003.
Shimizu, Akira; Kato, Michio; Hayashi, Koji; Fujisaki, Katsuo; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Katanishi, Shoji; Takada, Shoji; Inaba, Yoshitomo; et al.
JAERI-Tech 2003-033, 105 Pages, 2003/03
JAERI-Tech-2003-033.pdf:8.35MB
no abstracts in English
Sakaba, Nariaki; Nakagawa, Shigeaki; Tachibana, Yukio
Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.293 - 299, 2003/00
Safety demonstration tests using the HTTR are now underway in order to verify the inherent safety features and to improve the safety design and evaluation technologies for HTGRs, as well as to contribute to research and development for the VHTR, which is one of the Generation IV reactors. The first phase of the safety demonstration tests includes the reactivity insertion test by means of control-rod withdrawal and the coolant flow reduction test by tripping the gas circulators. The coolant flow reduction tests are simulation tests of anticipated transients without scram (ATWS). In the second phase of the safety demonstration tests, accident simulation tests will be conducted. This paper describes the plan of the overall safety demonstration tests and coolant flow reduction tests with test method, test conditions, and analytical and experimental results. From the results, it was found that the negative reactivity feedback of the core brings the reactor power safely to a stable level without a reactor scram in the case of a rapid decrease of the coolant flow rate after tripping of gas circulators.
Takeda, Takeshi; Nakagawa, Shigeaki; Kunitomi, Kazuhiko
Proceedings of 7th International Conference on Nuclear Engineering (ICONE-7) (CD-ROM), 10 Pages, 1999/00
no abstracts in English