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Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09
Times Cited Count:1 Percentile:63.33(Instruments & Instrumentation)Ebihara, Kenichi; Iwamoto, Takashi*; Matsubara, Yukio*; Yamada, Hiroki*; Okamura, Tsukasa*; Urushihara, Wataru*; Omura, Tomohiko*
ISIJ International, 54(1), p.153 - 159, 2014/01
Times Cited Count:13 Percentile:52.84(Metallurgy & Metallurgical Engineering)For understanding the mechanism of hydrogen embrittlement that is one cause of stress corrosion cracking, it is necessary to identify the location of hydrogen segregation (hydrogen existing state) in steels. The thermal desorption spectrum of hydrogen that is obtained by measuring hydrogen desorbing from specimens heated at a constant rate is a useful data for identifying the hydrogen existing state. In the paper, using the numerical simulation, we examined the difference of the thermal desorption spectra between two specimens of pre-strained high-strength steel, one was charged with hydrogen by the method used widely in laboratories, the other was by the method simulating hydrogen penetration in real environment. As a result, it was found that the difference results from the difference of the initial hydrogen distribution caused by the amount of charged hydrogen. If the amount of charged hydrogen is small, the thermal desorption spectrum is more sensitive to the initial distribution.
Ebihara, Kenichi; Iwamoto, Takashi*; Miwa, Noriaki*; Yamada, Hiroki*; Okamura, Tsukasa*; Urushihara, Wataru*; Omura, Tomohiko*
"Suiso Zeika Kenkyu No Kiban Kochiku" Kenkyukai Hokokusho, p.21 - 26, 2013/10
In order to explore the properly hydrogen-charging method for the estimation of hydrogen embrittlement of steels, in the workshop of Fundamental construction for hydrogen embrittlement supported by the Iron and Steel Institute of Japan of which I took part for understanding the mechanism of hydrogen embrittlement which is one cause of stress corrosion cracking, the thermal desorption spectrum of hydrogen and the amount of charged hydrogen were estimated among various kinds of steels charged with hydrogen by various methods. The presentation is a part of a series of the final report about the results obtained in the workshop. In the presentation, I talk about the numerical estimation of the desorption spectrum of low alloy steel mainly on the basis of the paper which is going to be published in the ISIJ International. Particularly, the kind of defects in the steel that capture hydrogen forming the spectrum and the experimental method for identifying the defects are explained in details.
Chikazawa, Yoshitaka; Enuma, Yasuhiro; Kisohara, Naoyuki; Yamano, Hidemasa; Kubo, Shigenobu; Hayafune, Hiroki; Sagawa, Hiroshi*; Okamura, Shigeki*; Shimakawa, Yoshio*
Proceedings of 2012 International Congress on Advances in Nuclear Power Plants (ICAPP '12) (CD-ROM), p.677 - 686, 2012/06
Evaluation of Earthquake and Tsunami on JSFR has been analyzed. For seismic design, safety components are confirmed to maintain their functions even against recent strong Earthquakes. As for Tsunami, some parts of reactor building might be submerged including component cooling water system whose final heat sink is sea water. However, in the JSFR design, safety grade components are independent from component cooling water system (CCWS). The JSFR emergency power supply adopts a gas turbine system with air cooling, since JSFR does not basically require quick start-up of the emergency power supply thanks to the natural convection DHRS. Even in case of long station blackout, the DHRS could be activated by emergency batteries or manually and be operated continuously by natural convection.
Okamura, Hiroyuki; Sakae, Hiroki*; Kidani, Keiji*; Hirayama, Naoki*; Aoyagi, Noboru; Saito, Takumi*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
Polyhedron, 31(1), p.748 - 753, 2012/01
Times Cited Count:29 Percentile:88.00(Chemistry, Inorganic & Nuclear)Okamura, Hiroki*; Tsuchida, Takashi*; Okada, Masao*; Yamagata, Ryohei; Seito, Hajime; Haruyama, Yasuyuki; Kaneko, Hirohisa
2011 Nen (Dai-29-Kai) Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.367 - 368, 2011/09
no abstracts in English
Okamura, Hiroyuki; Sakae, Hiroki*; Kidani, Keiji*; Hirayama, Naoki*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
no journal, ,
Kato, Atsushi; Chikazawa, Yoshitaka; Yamano, Hidemasa; Kubo, Shigenobu; Hayafune, Hiroki; Sagawa, Hiroshi*; Okamura, Shigeki*; Nakata, Shuhei*
no journal, ,
Earthquake and Tsunami proof of the Sodium-cooled Fast Reactor (SFR) has been evaluated. As for seismic design, safety grade components are confirmed to maintain their functions even against recent strong earthquakes. As for Tsunami, in the SFR design, safety grade components are independent from component cooling water system. A gas turbine system with air cooling is adopted for emergency power supply, since the SFR does not basically require quick start-up of the emergency power supply thanks to the natural convection Decay Heat Removal System (DHRS). Even in case of long station blackout, the DHRS could be activated by emergency batteries or manually and be operated continuously by natural convection.
Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
no journal, ,