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Kim, B. K.*; Tan, L.*; Sakasegawa, Hideo; Parish, C. M.*; Zhong, W.*; Tanigawa, Hiroyasu*; Kato, Yutai*
Journal of Nuclear Materials, 545, p.152634_1 - 152634_12, 2021/03
Times Cited Count：1 Percentile：15.7(Materials Science, Multidisciplinary)Ando, Masami; Nozawa, Takashi; Hirose, Takanori; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R. E.*; Myers, J.*
Fusion Science and Technology, 68(3), p.648 - 651, 2015/10
Times Cited Count：4 Percentile：32.95(Nuclear Science & Technology)Pressurized tubes of F82H and B-doped F82H irradiated at 573 and 673 K up to 
6dpa have been measured by a laser profilometer. The irradiation creep strain in F82H irradiated at 573 and 673 K was almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of 
BN-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573 K irradiation. For 673 K irradiation, the creep strain of some BN-F82H tubes was larger than that of F82H tubes. It is suggested that a swelling caused in each BN-F82H because small helium babbles might be produced by a reaction of B(n, 
) 
Li.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Sato, Masayasu; Isono, Takaaki; Sakurai, Shinji; Nakamura, Hirofumi; Sato, Satoshi; Suzuki, Satoshi; Ando, Masami; et al.
Fusion Engineering and Design, 81(8-14), p.1151 - 1158, 2006/02
Times Cited Count：124 Percentile：99.05(Nuclear Science & Technology)no abstracts in English
Nishio, Satoshi; Omori, Junji*; Kuroda, Toshimasa*; Tobita, Kenji; Enoeda, Mikio; Tsuru, Daigo; Hirose, Takanori; Sato, Satoshi; Kawamura, Yoshinori; Nakamura, Hirofumi; et al.
Fusion Engineering and Design, 81(8-14), p.1271 - 1276, 2006/02
Times Cited Count：20 Percentile：78.77(Nuclear Science & Technology)The design guideline for the blanket is decided to meet the mission of the DEMO plant which is expected to use technologies to be proven by 2020 and present an economical prospect of fusion energy in the operational time of the reactor. To moderate the technological extrapolation, the structural material of reduced activation ferritic steel (F82H), ceramic tritium breeder of Li
TiO
and neutron multiplier of Be are introduced. To improve the economical aspect, the coolant material of the supercritical water with inlet/outlet temperatures of 280/510
C, coolant pressure of 25 MPa is chosen. Resultantly the thermal efficiency of 41% is achieved. To obtain higher plasma performance, MHD instabilities suppressing shell structure is adopted with structural compatibility to the blanket structure. To meet higher plant availability requirement (more than 75%), the hot cell maintenance approach is selected for the replaceable power core components.
Okubo, Nariaki; Wakai, Eiichi; Matsukawa, Shingo; Tanigawa, Hiroyasu; Sawai, Tomotsugu; Jitsukawa, Shiro; Onuki, Somei*
Materials Transactions, 46(8), p.1779 - 1782, 2005/08
Times Cited Count：1 Percentile：16.26(Materials Science, Multidisciplinary)no abstracts in English
Okubo, Nariaki; Wakai, Eiichi; Matsukawa, Shingo*; Furuya, Kazuyuki; Tanigawa, Hiroyasu; Jitsukawa, Shiro
Materials Transactions, 46(2), p.193 - 195, 2005/02
Times Cited Count：1 Percentile：16.26(Materials Science, Multidisciplinary)no abstracts in English
Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Matsukawa, Shingo; Naito, Akira*; Jitsukawa, Shiro; Oka, Keiichiro*; Tanaka, Teruyuki*; Onuki, Somei*
JAERI-Review 2004-025, TIARA Annual Report 2003, p.159 - 161, 2004/11
The objectives of this study are to evaluate radiation hardening on ion-irradiated F82H up to 100 dpa and to examine the extra component of radiation hardening due to implanted helium atoms (up to 3000 appmHe) in F82H under ratio of 0, 10, 100 appmHe/dpa.The ion-beam irradiation experiment was carried out at the TIARA facility of JAERI. Specimens were irradiated at 633 K by 10.5 MeV Fe ions with/without 1.05 MeV He ions. Micro-indentation tests were performed at loads to penetrate about 0.40 mm in the irradiated specimens using an UMIS-2000. The results are summarized as follows:1) As a result of the single irradiated F82H, the micro-hardness tended to increase about 30 dpa. 2) The extra radiation hardening was obviously caused by co-implanted helium atoms more than 1000 appm in F82H irradiated at 633 K. 3) In the dual-beam (100 appmHe/dpa) irradiated microstructure, nano-voids and fine defects were observed. It is suggested that the formation of nano-voids causes the extra radiation hardening by helium co-implantation.
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.
Hirose, Takanori; Shiba, Kiyoyuki; Sawai, Tomotsugu; Jitsukawa, Shiro; Akiba, Masato
Journal of Nuclear Materials, 329-333(Part1), p.324 - 327, 2004/08
Times Cited Count：55 Percentile：94.79(Materials Science, Multidisciplinary)Reduced activation ferritic/martensitic steel, RAFs is the leading candidates for the structural materials of breeding blankets. HIP is examined as a near-net-shape fabrication process for this structure. The HIP requires heating above the normalizing temperature and the final microstructural features depends on the HIP processing conditions. Conventional HIP process caused a prior-austenite grain (PAG) coarsening of RAFs and subsequent increase of ductile brittle transition temperature. Japanese RAFs F82H and its modified steels were investigated by metallurgical method after isochronal heat treatment up to 1473K simulating HIP equivalent thermal hysteresis. Although Conventional F82H IEA heat showed significant grain growth after conventional solid HIP conditions (1313K 
2hr.), F82H with 0.1wt.% tantalum kept fine grain after the same heat treatment. On the other hands, conventional RAF/Ms with coarse grain were recovered by the post HIP normalizing at temperature below TaC dissolution temperature. This process can refine the PAG size of F82H more than ASTM grain size number 7.
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：75.17(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.
Ogawa, Hiroaki; Yamauchi, Yuji*; Tsuzuki, Kazuhiro; Kawashima, Hisato; Sato, Masayasu; Shinohara, Koji; Kamiya, Kensaku; Kasai, Satoshi; Kusama, Yoshinori; Yamaguchi, Kaoru*; et al.
Journal of Nuclear Materials, 329-333(Part1), p.678 - 682, 2004/08
Times Cited Count：4 Percentile：29.18(Materials Science, Multidisciplinary)no abstracts in English
Tsuzuki, Kazuhiro; Shinohara, Koji; Kamiya, Kensaku; Kawashima, Hisato; Sato, Masayasu; Kurita, Genichi; Bakhtiari, M.; Ogawa, Hiroaki; Hoshino, Katsumichi; Kasai, Satoshi; et al.
Journal of Nuclear Materials, 329-333(1), p.721 - 725, 2004/08
Times Cited Count：7 Percentile：45.06(Materials Science, Multidisciplinary)no abstracts in English
Shiba, Kiyoyuki; Enoeda, Mikio; Jitsukawa, Shiro
Journal of Nuclear Materials, 329-333(Part1), p.243 - 247, 2004/08
Times Cited Count：53 Percentile：94.41(Materials Science, Multidisciplinary)no abstracts in English
Wakai, Eiichi; Taguchi, Tomitsugu; Yamamoto, Toshio*; Kato, Yoshiaki; Takada, Fumiki
Materials Transactions, 45(8), p.2638 - 2640, 2004/08
Times Cited Count：1 Percentile：12.41(Materials Science, Multidisciplinary)no abstracts in English
Kurihara, Ryoichi
JAERI-Tech 2004-052, 39 Pages, 2004/07
The problems in the thermal structural design of the plasma facing component such as the blanket first wall and the divertor plate which receives very high heat flux were examined in the design of the fusion power reactors. Compact high fusion power reactor must give high heat flux and high-speed neutron flux from the plasma to the first wall and the divertor plate. In this environmental situation, the micro cracks should be generated in material of the first wall. Structural integrity of the first wall would be very low during the operation of the reactor, if those micro-cracks grow in a crack having significant size by the fatigue or the creep. The crack penetration in the first wall can be a factor which threatens the safety of the fusion power reactor. This paper summarizes the problems on the structural integrity in the first wall made of the SiC/SiC composite material or the ferritic steel.
Matsukawa, Makoto; JT-60SC Design Team
IEEE Transactions on Applied Superconductivity, 14(2), p.1399 - 1404, 2004/06
Times Cited Count：4 Percentile：28.61(Engineering, Electrical & Electronic)no abstracts in English
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Hashimoto, Naoyuki*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.33 - 36, 2004/04
Extraction replica samples were prepared from F82H-IEA, F82H HT2, JLF-1 and ORNL9Cr to analyze the precipitate distribution. The samples were examined to obtain precipitate size distribution with TEM and to analyze chemical composition distribution with SEM. Back-scattered electron imaging was found to be the effective way to separate Ta-rich precipitate from other precipitates. Results showed that most of the precipitates were M23C6, and the shape is a round ellipsoid in F82H-IEA and HT2, but was a long ellipsoid in JFL-1 and ORNL9Cr. It was also found that MX precipitates were few and large and contain Ti in F82H-IEA and HT2, but a lot of fine MX precipitates without Ti were observed in JLF-1 and ORNL9Cr.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.30 - 32, 2004/04
Extraction residue was made from several HFIR 11J-irradiated RAFs, and the mass change was measured to investigate the irradiation-enhanced change in precipitation. Two different types of filter with coarse and fine pores were used in order to separate the difference of irradiation effects between larger and smaller precipitates. Unirradiated specimens were examined as well. Results suggest that during irradiation the mass of larger precipitates increased in F82H-IEA, Ni-doped F82H, JLF-1 and ORNL9Cr, fine precipitates disappeared in JLF-1, and fine precipitates increased in Ni-doped F82H.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Payzant, E. A.*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.37 - 40, 2004/04
XRD analyses were performed on the extraction residue of HFIR 11J-irradiated RAFs to investigate the overall precipitate character. Un-irradiated and aged specimens were examined as well. Results suggested that the distinctive peaks of M23C6 (M; Cr, Fe, W) were observed on all specimens. Peaks possibly related to MX (M;Ta,Ti,V : X ; C, N) were observed on the specimens extracted from un-irradiated JLF-1 and ORNL9Cr, but those peaks were not observed on irradiated specimens.
Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sokolov, M. A.*; Klueh, R. L.*; Ando, Masami
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.58 - 60, 2004/04
1TCT fracture toughness specimens of F82H-IEA steel were fatigue precracked and sliced in specimen thickness wise for microstructure analysis around the precrack. The microstructure around the precrack was observed by optical microscopy (OM), scanning electron microscopy (SEM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM). TEM samples around the crack front were prepared by focused ion beam (FIB) processor. The fracture surfaces of tested 1TCT specimens were also observed. OM observation showed that the precrack penetration was straight in the beginning, and then tended to follow a prior austenite grain boundary and to branch into 2 to 3 directions at the terminal. SEM and OIM observations revealed that the both microstructures around the precracks and ahead of the precrack had turned into cell structure, which is the typical microstructure of fatigue-loaded F82H. TEM images and inverse pole figures obtained from the crack-front region confirmed this structure change.
