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Otsuka, Satoshi; Kaito, Takeji; Inoue, Masaki; Asayama, Tai; Kim, S.-W.; Ukai, Shigeharu*; Narita, Takeshi*; Sakasegawa, Hideo*
Journal of Nuclear Materials, 386-388, p.479 - 482, 2009/04
Times Cited Count：19 Percentile：76.21(Materials Science, Multidisciplinary)This paper discusses the effects of small portion of Al contamination (
0.1wt%) on the high-temperature strength and microstructure of 9Cr-ODS steel. Increasing Al concentration is shown to provide small reduction of ultimate tensile strength as well as 0.2% proof stress at 973 K and 1073 K accompanied by reduction of elongated grains i.e. residual-
ferrite acting as reinforcement phase. Addition of Al appears to increase the proportion of ferrite phase, which is contrary to general behavior in conventional steels. This unique behavior could be peculiar to the non-equilibrium materials such as mechanically-alloyed alloy. Computer simulation on phase transformation suggests that the fine oxide dispersion in the elongated ferrite could be attributable to the preferential partitioning of Ti and W in ferrite than in austenite at hot-extrusion process at 1423 K.
Otsuka, Satoshi; Ukai, Shigeharu; Sakasegawa, Hideo; Fujiwara, Masayuki; Kaito, Takeji; Narita, Takeshi
Journal of Nuclear Materials, 367-370(1), p.160 - 165, 2007/08
Times Cited Count：59 Percentile：95.87(Materials Science, Multidisciplinary)This paper describes the effect on creep strength and microstructure of 9Cr-oxide dispersion strengthened martensitic steel (9Cr-ODS steel) brought by the differences in titanium concentration and consolidation temperature. The increase of titanium concentration to 0.30-0.35wt% was shown to provide remarkable improvement of creep strength accompanied by the increase of residual-alpha ferrite. The elevation of hot-extrusion temperature notably degraded the creep strength, however, appeared to increase the volume fraction of residual-alpha ferrite. Creep deformation process of 9Cr-ODS steel was discussed to explain these results based on microstructure observations.
Kamiyama, Takashi*; Seki, Naoki*; Iwasa, Hirokatsu*; Uchida, Tsutomu*; Ebinuma, Takao*; Narita, Hideo*; Igawa, Naoki; Ishii, Yoshinobu; Bennington, S. M.*; Kiyanagi, Yoshiaki*
Physica B; Condensed Matter, 385-386(1), p.202 - 204, 2006/11
Times Cited Count：7 Percentile：35.12(Physics, Condensed Matter)no abstracts in English
Saito, Kimiaki; Kunieda, Etsuo*; Narita, Yuichiro*; Kimura, Hideo; Hirai, Masaaki*; Deloar, H. M.*; Kaneko, Katsutaro*; Ozaki, Masahiro*; Fujisaki, Tatsuya*; Myojoyama, Atsushi*; et al.
Radiation Protection Dosimetry, 116(1-4), p.190 - 195, 2005/12
Times Cited Count：2 Percentile：17.6(Environmental Sciences)A dose calculation system for providing accurate dose distribution in a patient body is under developing for supporting radiotherapy using photons and electrons. In this system, a sophisticated human model, a precise accelerator head model, and a Monte Carlo calculation will be utilized to perform realistic simulation. The dose distribution is calculated by this system on the ITBL computer at the dose calculation center, and the related data are transferred through a network. This system is intended to support the quality assurance of current treatments carried out in Japan. Further, this system is planned to apply to advanced radiotherapy. The project started on November 2003 and is scheduled to continue for five years. Prototypes of some parts constituting the system have been already developed, and the fundamental features on the radiation fields have been investigated. On the basis of the fundamental investigation, the final system will be designed and constructed.
Yaita, Tsuyoshi; Narita, Hirokazu*; Suzuki, Shinichi; Shiwaku, Hideaki; Motohashi, Haruhiko; Ono, Hideo; Usami, Noriko*; Kobayashi, Katsumi*
Photon Factory Activity Report 1997, P. 81, 1997/00
no abstracts in English
Ukai, Shigeharu; Kaito, Takeji; Otsuka, Satoshi; Narita, Takeshi; Sakasegawa, Hideo
no journal, ,
The composition of martensitic 9Cr-ODS steels was optimized from the balancing of the residual alpha hard and F/M soft grains. The claddings with the optimized composition of 9Cr-0.14C-2W-0.3Ti-0.35Y
O
as well as standard were manufactured and their mechanical properties satisfied the design criteria for SFR fuel.
Otsuka, Satoshi; Ukai, Shigeharu; Fujiwara, Masayuki; Kaito, Takeji; Narita, Takeshi; Sakasegawa, Hideo
no journal, ,
Japan Atomic Energy Agency (JAEA) has gone ahead on with the research and development of the advanced type sodium (Na)-cooled fast reactors, and come to the conclusion that the high performance nuclear fuel resisting to high burn-up -250GWD/t: 250dpa- and high-temperature operation -700
C- is indispensable for adequate economical operation. JAEA has developed a manufacturing process of the cladding tube made of 9CrODS martensitic steel (9CrODS), and accumulated knowledge by fabricating several hundred of the tube. These activities have led to the resounding success in establishing a fabrication process of the 9CrODS tube having the target creep strength of 700C
120MPa (in hoop)10,000h. In recent years, our efforts have been made to develop a microstructure control technique that further improves the creep strength, a large scale manufacturing procedure, a database on environment effects including radiation damage and corrosion resistance, and so on. In addition, under the contribution to the Super ODS project sponsored by MEXT, the modification of the ODS steel has been started for the application to the high burn-up cladding tube of lead-bismuth eutectic (LBE)-cooled reactor and super critical pressurized water (SCW)-cooled reactor. In this presentation, we will report the current status on the 9CrODS development in JAEA, in particular the microstructure control procedure for high-temperature strength improvement as well as the compatibility of the 9CrODS steel with LBE.
Seki, Naoki*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Iwasa, Hirokatsu*; Hiraga, Fujio*; Uchida, Tsutomu*; Igawa, Naoki; Yamauchi, Hiroki; Ishii, Yoshinobu; Ebinuma, Takao*; et al.
no journal, ,
no abstracts in English
