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Takeda, Takeshi
International Journal of Nuclear Energy, 2014, p.803470_1 - 803470_17, 2014/00
Ohashi, Hirofumi; Sato, Hiroyuki; Goto, Minoru; Yan, X.; Sumita, Junya; Tazawa, Yujiro*; Nomoto, Yasunobu; Aihara, Jun; Inaba, Yoshitomo; Fukaya, Yuji; et al.
International Journal of Nuclear Energy, 2013, p.918567_1 - 918567_18, 2013/00
Japan Atomic Energy Agency (JAEA) has conducted a conceptual design of a 50 MWt small-sized high temperature gas cooled reactor (HTGR) for multiple heat applications, named HTR50S, with the reactor outlet coolant temperature of 750 
C and 900 C. It is first-of-a-kind of the commercial plant or a demonstration plant of a small-sized HTGR system to deploy it in developing countries in the 2020s. The design concept of HTR50S is to satisfy the user requirements for multipurpose heat application, to upgrade its performance compared to that of HTTR without significant R&D utilizing the knowledge obtained by the HTTR design and operation, and to fulfill the high level of safety by utilizing the inherent features of HTGR and a passive decay heat removal system.
Kaji, Yoshiyuki; Miwa, Yukio*; Shibata, Akira; Nakano, Junichi; Tsukada, Takashi; Takakura, Kenichi*; Nakata, Kiyotomo*
International Journal of Nuclear Energy Science and Engineering, 2(3), p.65 - 71, 2012/09
Crack growth rate (CGR) tests have been conducted with neutron irradiated compact tension (CT) specimens. The specimens were irradiated in the core region of the Japan Materials Testing Reactor (JMTR) in simulated BWR water environments at 288 C from 0.37 to 5.55
10
n/m
(E
1 MeV) (0.62 to 9.2 dpa). The CGRs of base metals in high electrochemical corrosion potential (ECP) condition with 10 
stress intensity factor, K 30 MPam
, increased with increasing neutron fluence until 2 dpa and the CGRs were almost the same from 2 to 10 dpa. We investigated the influence of microstructure on CGR by microstructure observation and local strain measurement around the precipitate. This paper will discuss the relationship between CGR and microstructure, radiation hardening, radiation induced segregation.
Yanagisawa, Kazuaki
International Journal of Nuclear Energy Science and Technology, 6(1), p.55 - 63, 2011/00
The Japan Materials Testing Reactor (JMTR) loaded the 4.8g/cc silicide fuel for the core conversion from the high to the low enrichment ( 20wt%). In the experiment, the reactivity insertion of 0.35% per s, caused by the by the abnormal withdrawal of the control rod at the start up of the JMTR was assumed. The value was about twice the EUREKA2 computer code used for the licensing. As a result, the test specimen (4.8g/cc silicide fuel) had the peak cladding surface temperature of 137 C. The test specimen did not fail by quench mechanism because the time to quench tq was 0.11s and the temperature drop was 28 C. Usually the quench failure occurs at the rapid tq ( 0.13s) and the high temperature drop ( 94 C). The safety margin of the JMTR against the accident induced by the abnormal withdrawal of control rod was assured.
Yanagisawa, Kazuaki
International Journal of Nuclear Energy Science and Technology, 4(2), p.97 - 110, 2008/00
The pulse irradiation tests were conducted on silicide mini-plate fuels, prepared for a peaceful application of nuclear energy. The major findings are: (1) Neither failure nor degradation of dimensional stability of the fuel occurred in the temperature below 400 C. Beyond that level a dimensional stability was gradually degraded with an increase of temperature. (2)The fuels were intact at energy depositions 82 cal/g but were damaged at energy depositions of 94 cal/g, where the failure mode is wither through-plate cracking or fuel melt. A failure threshold must be existed between the two values.
Yanagisawa, Kazuaki
International Journal of Nuclear Energy Science and Technology, 4(2), p.97 - 110, 2008/00
The pulse irradiation tests were conducted on silicide mini-plate fuels, prepared for a peaceful application of nuclear energy. The major findings are: (1) Neither failure nor degradation of dimensional stability of the fuel occurred in the temperature below 400 C. Beyond that level a dimensional stability was gradually degraded with an increase of temperature. (2) The fuels were intact at energy depositions below 82 cal/g but were damaged at energy depositions of above 94 cal/g, where the failure mode is wither through-plate cracking or fuel melt. A failure threshold must be existed between the two values.
