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Kakiuchi, Kazuo; Yamauchi, Akihiro*; Amaya, Masaki; Udagawa, Yutaka; Kitano, Koji*
Proceedings of TopFuel 2022 (Internet), p.409 - 418, 2022/10
Kakiuchi, Kazuo; Udagawa, Yutaka; Yamauchi, Akihiro*
JAEA-Research 2022-001, 21 Pages, 2022/06
JAEA-Research-2022-001.pdf:1.84MB
The primary cause of cladding embrittlement during loss-of-cool ant accident (LOCA) is the increase in oxygen concentration in the metallic layer and associated microstructural change due to oxidation. In the case of cladding high temperature rupture, inner surface oxidation by the steam ingress and the consequent increase in hydrogen partial pressure result in hydrogen absorption (secondary hydriding) localized in the axial direction at the distance apart from the rupture opening as is well known from preceding studies. In order to understand the effect of cladding microstructural changes on mechanical property of a fuel rod under LOCA conditions in a more precise and quantitative manner, the nanoindentation method has been applied to evaluation of mechanical properties of a cladding specimen after a LOCA simulated test; results for two samples taken from the rupture opening part and secondary hydriding part were compared with each other. The fraction of plastic work during the indentation was evaluated from the load-displacement curve in addition to hardness and Young's modulus. The plastic work fraction at the secondary hydriding part was found to be clearly lower than that at the rupture opening part and rather close to that in the ZrO
and 
-Zr(O) layers, suggesting the significant ductility reduction of the secondary hydriding part despite its relatively low oxygen concentration.
Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.
Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03
Times Cited Count：1 Percentile：0(Materials Science, Multidisciplinary)The layered perovskite PrBaCoO
demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCoO is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.
Udagawa, Yutaka; Yamauchi, Akihiro*; Kitano, Koji*; Amaya, Masaki
JAEA-Data/Code 2018-016, 79 Pages, 2019/01
JAEA-Data-Code-2018-016.pdf:2.75MB
FEMAXI-8 is the latest version of the fuel performance code FEMAXI developed by JAEA. A systematic validation work has been achieved against 144 irradiation test cases, after many efforts have been made, in development of new models, improvements in existing models and the code structure, bug-fixes, construction of irradiation-tests database and other infrastructures.
Yamauchi, Akihiro*; Amaya, Masaki
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 7 Pages, 2018/10
Differential scanning calorimetry (DSC) measurements on pre-hydrided cold worked, stress relieved and recrystallized Zry-4 cladding were performed in a temperature range between 50 and 600
C in order to elucidate the effect of final heat treatment at fabrication of Zircaloy-4 (Zry-4) cladding on the terminal solid solubility during the dissolution of zirconium hydrides at heating up (TSSD). Obtained DSC curves and Metallography indicate that the initial state of hydrides affects the dissolution behavior of hydride. The Arrhenius plots of the TSSD temperatures and hydrogen contents obtained from this study revealed that cold worked samples exhibited the largest TSSD and followed by stress relieved and recrystallized samples. The results of this study indicated that the difference in microstructure due to final heat treatment at fabrication of Zry-4 cladding affects the dissolution behavior of hydrides.
Hiraishi, Masatoshi*; Iimura, Soshi*; Kojima, Kenji*; Yamaura, Junichi*; Hiraka, Haruhiro*; Ikeda, Kazutaka*; Miao, P.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Miyazaki, Masanori*; et al.
Nature Physics, 10(4), p.300 - 303, 2014/04
Times Cited Count：101 Percentile：95.69(Physics, Multidisciplinary)Saito, Junichi; Ara, Kuniaki; Sugiyama, Kenichiro*; Kitagawa, Hiroshi*; Yamauchi, Miho*; Yamashita, Akihiro*; Oka, Nobuki*; Yoshioka, Naoki*
no journal, ,
no abstracts in English
Otomo, Manabu; Yamauchi, Yasushi*; Yamamura, Noyuri*; Avramov, P.; Matsumoto, Yoshihiro; Entani, Shiro; Koide, Akihiro*; Naramoto, Hiroshi*; Amemiya, Kenta*; Fujikawa, Takashi*; et al.
no journal, ,
no abstracts in English
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Ishida, Akihiro*; Yamashita, Tomohiro*; Katahira, Kei*; Pikuz, T.; Faenov, A.*; Esirkepov, T. Z.; Pirozhkov, A. S.; et al.
no journal, ,
We will tell about the measurement methods of the electron temperature from the laser-driven acceleration.
Sakai, Seiji; Matsumoto, Yoshihiro*; Entani, Shiro; Naramoto, Hiroshi*; Koide, Akihiro*; Fujikawa, Takashi*; Yamauchi, Yasushi*; Amemiya, Kenta*
no journal, ,
no abstracts in English
Yamauchi, Akihiro*; Amaya, Masaki
no journal, ,
no abstracts in English
Yamauchi, Akihiro*; Amaya, Masaki
no journal, ,
no abstracts in English
Yamauchi, Akihiro*; Kakiuchi, Kazuo; Udagawa, Yutaka; Kitano, Koji*
no journal, ,
no abstracts in English
Rekimoto, Masafumi; Ando, Masato; Chikazawa, Yoshitaka; Kato, Atsushi; Hamano, Tomoharu; Shiohama, Yasutaka; Miyagawa, Takayuki*; Uzawa, Masayuki*; Hara, Hiroyuki*; Yamauchi, Kanau*; et al.
no journal, ,
no abstracts in English
Kakiuchi, Kazuo; Yamauchi, Akihiro*
no journal, ,
no abstracts in English
