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Mitsuhara, Masatoshi*; Kurino, Koichi*; Yano, Yasuhide; Otsuka, Satoshi; Toyama, Takeshi*; Onuma, Masato*; Nakashima, Hideharu*
Tetsu To Hagane, 109(3), p.189 - 200, 2023/03
Times Cited Count：0 Percentile：0(Metallurgy & Metallurgical Engineering)Oxide Dispersion Strengthened (ODS) ferritic steel, a candidate material for fast reactor fuel cladding, has low thermal expansion, good thermal conductivity, and excellent resistance to irradiation damage and high temperature strength. The origin of the excellent high-temperature strength lies in the dispersion of fine oxides. In this study, creep tests at 700 or 750
C, which are close to the operating temperatures of fast reactors, and high-temperature tensile tests at 900 to 1350 C, which simulate accident conditions, were conducted on 9Cr ODS ferritic steels, M11 and MP23, and 12Cr ODS ferritic steel, F14, to confirm the growth behavior of oxides. In the M11 and F14 creep test samples, there was little oxide growth or decrease in number density from the initial state, indicating that dispersion strengthening by oxides was effective during deformation. After creep deformation of F14, the development of dislocation substructures such as dislocation walls and subgrain boundaries was hardly observed, and mobile dislocations were homogeneously distributed in the grains. The dislocation density increased with increasing stress during the creep test. In the high-temperature ring tensile tests of MP23 and F14, the strength of both steels decreased at higher temperatures. In MP23, elongation decreased with increasing test temperature from 900 to 1100 C, but increased at 1200 C, decreased drastically at 1250 C, and increased again at 1300 C. In F14, elongation decreased with increasing temperature. It was inferred that the formation of the 
-ferrite phase was responsible for this complex change in mechanical properties of MP23 from 1200 to 1300 C.
Wakai, Eiichi; Sato, Michitaka*; Okubo, Nariaki; Sawai, Tomotsugu; Shiba, Kiyoyuki; Jitsukawa, Shiro
Nihon Kinzoku Gakkai-Shi, 69(6), p.460 - 464, 2005/06
Times Cited Count：1 Percentile：16.27(Metallurgy & Metallurgical Engineering)no abstracts in English
Department of Materials Science; Department of Fusion Engineering Research (Tokai Site)
JAERI-Review 2004-018, 97 Pages, 2004/08
JAERI-Review-2004-018.pdf:18.92MB
Extensive efforts for evaluating the irradiation performances of a reduced activation ferritic/martensitic steel (RAF/M) of F82H* and other several RAF/Ms have been made in recent several years. They are, examinations of the effects of neutron irradiation on (1) Ductile to brittle transition temperature (DBTT) up to a damage level of 20 dpa to explore lower temperature limit, (2) Enhanced He effect on DBTT shift for Ni/B doped heats (isotopic tailoring method was used for B doping), (3) Susceptibility to environmentally assisted cracking by the slow strain rate tensile tests (SSRT) in a high temperature pressurized water and (4) Flow stress-plastic strain relation obtained by measuring the profile of the specimen during tensile testing, together with the activities of (5) the development of the test methods after neutron irradiation and (6) other supporting researches. Results are summarized in the present report. They clearly indicate the good applicability of RAF/Ms to fusion machines.
Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sakasegawa, Hideo*; Klueh, R. L.*; Sokolov, M. A.*; Shiba, Kiyoyuki; Jitsukawa, Shiro; Koyama, Akira*
Journal of Nuclear Materials, 329-333(1), p.283 - 288, 2004/08
Times Cited Count：19 Percentile：75.21(Materials Science, Multidisciplinary)Reduced-activation ferritic/martensitic steels (RAFs) were developed as candidate structural materials for fusion power plants. In a previous study, it was reported that ORNL9Cr-2WVTa and JLF-1 (Fe-9Cr-2W-V-Ta-N) steels showed smaller ductile-brittle transition temperature (DBTT) shifts compared to IEA modified F82H (Fe-8Cr-2W-V-Ta) after neutron irradiation up to 5 dpa at 573K. This difference in DBTT shift could not be interpreted as an effect of irradiation hardening, and it is also hard to be convinced that this difference was simply due to a Cr concentration difference. To clarify the mechanisms of the difference in Charpy impact property between these steels, various microstructure analyses were performed.
Tanigawa, Hiroyasu; Hirose, Takanori; Ando, Masami; Jitsukawa, Shiro; Kato, Yudai*; Koyama, Akira*
Journal of Nuclear Materials, 307-311(Part1), p.293 - 298, 2002/12
Times Cited Count：9 Percentile：51.46(Materials Science, Multidisciplinary)It has been a key issue to get the mechanical understanding of fracture process on microstructure basis, especially on neutron-irradiated materials, but not yet to be understood well enough as for the difficulty of making transmission electron microscope (TEM) thin film sample from mechanical-tested specimen. To solve this technical problem, the focused ion beam (FIB) micro-sampling system was installed to the Research Hot Laboratory of Japan Atomic Research Institute (JAERI), Japan. This system makes it possible to fabricate the TEM specimens from the critical points of mechanical-tested radioactive specimens, such as the crack initiation points of fatigue fracture on neutron irradiated specimen. In this paper, the microstructure of mechanical-tested specimen of Reduced Activation Ferritic/martensitic steels, RAFs are investigated focusing on the helium effects to fatigue fracture.
Wakai, Eiichi; Miwa, Yukio; Hashimoto, Naoyuki*; Robertson, J. P.*; Klueh, R. L.*; Shiba, Kiyoyuki; Abiko, Kenji*; Furuno, Shigemi*; Jitsukawa, Shiro
Journal of Nuclear Materials, 307-311(Part.1), p.203 - 211, 2002/12
Times Cited Count：26 Percentile：82.31(Materials Science, Multidisciplinary)no abstracts in English
Harada, Yuhei; Maruyama, Yu; Maeda, Akio*; Chino, Eiichi; Shibazaki, Hiroaki*; Kudo, Tamotsu; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun
Journal of Nuclear Science and Technology, 37(6), p.518 - 529, 2000/06
no abstracts in English
; Yamagata, Ichiro; Donomae, Takako; Akasaka, Naoaki
JNC TN9400 2000-046, 24 Pages, 2000/02
lt is well known that solute atoms are segregated on surface, grain boundary, etc. and composition changed partially in irradiated austenitic stainless steel. For understanding radiation induced segregation (RIS), we adopt a Fe-15Cr-20Ni-x (x: Si, Mo) which is basically alloy system in PNC1520, and size of Si, Mo are different from matrix atoms to investigate RIS behaviors. The specimens were irradiated by "Joyo" fast reactor that irradiation condition is 3.5 
10
n/m
(E>0.1Mev) at 476C. After irradiation, the specimen were observed and analyzed with EDS (Energy Dispersive X-ray Spectroscope) of 400kV TEM (Transmission Electron Microscope). The behavior of RIS depends on size of solute atoms of alloy. For example, oversized atoms are decreased and undersized atoms are increased in sink. RIS of voids are as same as or more than grain boundaries and smaller than precipitates. The void denuded zone was existed nearby G.B. in case of combinations between the grains from G.B.0ne of the reasons in this, the voids swepted by moving G.B. in radiation induced G.B. migration.
CWakai, Eiichi; Hashimoto, N.*; J.P.Robertson*; Sawai, Tomotsugu; Hishinuma, Akimichi
Fusion Materials, 313(25), p.197 - 201, 1999/04
no abstracts in English
B and F82H+
Ni steelsWakai, Eiichi; Hashimoto, N.*; Shiba, Kiyoyuki; Miwa, Yukio; J.P.Robertson*; R.L.Klueh*
Fusion Materials, 313(25), p.161 - 169, 1999/04
no abstracts in English
O
containing CrO or TiO*; Katano, Yoshio; Noda, Kenji
Journal of Nuclear Materials, 258-263, p.1831 - 1835, 1998/00
Times Cited Count：1 Percentile：15.03(Materials Science, Multidisciplinary)no abstracts in English
O irradiated with multiple ion beams of H,He and O and after annealingKatano, Yoshio; ; Yamaki, Daiju; Aruga, Takeo; Noda, Kenji
Journal of Nuclear Materials, 258-263, p.1842 - 1847, 1998/00
Times Cited Count：6 Percentile：49.22(Materials Science, Multidisciplinary)no abstracts in English
Hamada, Shozo; Miwa, Yukio; Yamaki, Daiju; Katano, Yoshio; ; Noda, Kenji
Journal of Nuclear Materials, 258-263, p.383 - 387, 1998/00
Times Cited Count：18 Percentile：79.15(Materials Science, Multidisciplinary)no abstracts in English
O irradiated with multiple beams of H,He and O ions and after annealing at 1273KKatano, Yoshio; ; Yamaki, Daiju; Aruga, Takeo; Noda, Kenji; Yamamoto, Shunya
Nuclear Instruments and Methods in Physics Research A, 140(1-2), p.152 - 158, 1998/00
no abstracts in English
O irradiated with triple beams of O,H and He ionsKatano, Yoshio; Hojo, Kiichi; ; Yamaki, Daiju; Aruga, Takeo; Noda, Kenji
Nuclear Instruments and Methods in Physics Research B, 141(1-4), p.411 - 418, 1998/00
Times Cited Count：6 Percentile：49.22(Instruments & Instrumentation)no abstracts in English
Hamada, Shozo
JAERI-Tech 97-041, 180 Pages, 1997/08
no abstracts in English
Nihon Genshiryoku Gakkai-Shi, 39(5), p.10 - 13, 1997/00
no abstracts in English
Hamada, Shozo; Y.C.Zhang*; Miwa, Yukio; Yamaki, Daiju
Radiation Physics and Chemistry, 50(6), p.555 - 559, 1997/00
Times Cited Count：9 Percentile：59.76(Chemistry, Physical)no abstracts in English
Genshiryoku Kogyo, 42(6), p.24 - 27, 1996/00
no abstracts in English
CB.J.Marsden*; ; R.Charles*
Proc. of meeting: Open Discussion on Current Issues in Nuclear Graphite and Carbon Topics, 0, 1 Pages, 1996/00
no abstracts in English
