Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nozawa, Takashi; Tanigawa, Hiroyasu; Park, J.-S.*; Koyama, Akira*
Proceedings of 33rd International Conference on Advanced Ceramics and Composites (CD-ROM), p.65 - 76, 2009/09
SiC/SiC composites are promising candidate materials for various energy industries. One of key issues for their practical application is to develop design basis of quasi-ductile composites. Understanding the crack propagation behavior is therefore essential. For this purpose, determining a fracture resistances undoubtedly important and this paper aims to evaluate this using various types of notched specimens. With the preliminary analysis by the authors, a new methodology to determine the fracture resistance has been developed based on the non-linear fracture mechanics, separately discussing the effect of irreversible energies. By adopting this method for nano-infiltration transient-eutectic-phase sintered (NITE) SiC/SiC composites, several key findings were obtained: (1) notch insensitivity, (2) no significant size effect, and (3) superior crack tolerance.
Kim, S.-W.; Tanigawa, Hiroyasu; Hirose, Takanori; Koyama, Akira*
Journal of Nuclear Materials, 386-388, p.529 - 532, 2009/04
Times Cited Count：13 Percentile：64.74(Materials Science, Multidisciplinary)Low cycle fatigue (LCF) results at ambient temperature under diametral strain controlled conditions of the reduced activation ferritic/martensitic steel, F82H IEA heat before and after neutron irradiated samples are reported. The results show that cyclic softening behavior is the main mechanical feature observed in this material. A detailed analysis for the hysteresis loops was carried out to determine the friction and back stresses. The friction stress is equivalent to the resistance which the dislocations have to overcome to keep moving in the lattice. The back stress depends on the density of long-range impenetrable obstacles that are created by the dislocations movement such as pile-ups. The cyclic softening of F82H IEA heat is related with the decrease of the friction stress. Moreover, the friction and back stress behavior of neutron irradiated samples show significantly different behavior than those of unirradiated samples.
Tanigawa, Hiroyasu; Hirose, Takanori; Shiba, Kiyoyuki; Kasada, Ryuta*; Wakai, Eiichi; Serizawa, Hisashi*; Kawahito, Yosuke*; Jitsukawa, Shiro; Kimura, Akihiko*; Kono, Yutaka*; et al.
Fusion Engineering and Design, 83(10-12), p.1471 - 1476, 2008/12
Times Cited Count：78 Percentile：97.72(Nuclear Science & Technology)Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. F82H, which were developed and studied in Japan, was designed with an emphasis on high temperature properties and weldability. The database on F82H properties is currently the most extensive available among the existing RAFMs. The objective of this paper is to review the R&D status of F82H and to identify the key technical issues for the fabrication of an ITER Test Blanket Module (TBM) suggested by recent achievements in Japan.
Nozawa, Takashi; Hinoki, Tatsuya*; Koyama, Akira*; Tanigawa, Hiroyasu
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10
Silicon carbide composites (SiC/SiC) are promising candidate materials for fusion reactors with advanced features such as high thermal efficiency. This paper will provide a present status in development of design basis for quasi-ductile SiC/SiC as a structural application. For that purpose, failure behavior, i.e., matrix cracking behavior, of a new class of radiation-resistant SiC/SiC, e.g., a nano-infiltration transient-eutectic phase (NITE) SiC/SiC, was evaluated. With a fact of the notch-insensitivity and very minor size effect on the failure behavior, a stress criterion is suggested in failure of NITE-SiC/SiC.
Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Hirose, Takanori; Kasada, Ryuta*; Wakai, Eiichi; Jitsukawa, Shiro; Kimura, Akihiko*; Koyama, Akira*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 6 Pages, 2007/03
The status of research and development of reduced activation martensitic steels (RAMs) in Japan are reviewed and key issues suggested from recent achievements in Japan since the last conference are highlighted, with the aim of the fabrication for the ITER Test Blanket Module (TBM) and application for the DEMO reactor. It was pointed out that international collaboration would be desirable for research on key issues such as precipitate stability under irradiation or Ta effects which are common for all RAMs and require an extensive research effort.
Yoshikawa, Kiyoshi*; Takiyama, Ken*; Onishi, Masami*; Yamamoto, Yasushi*; Nagasaki, Kazunobu*; Masuda, Kai*; Toku, Hisayuki*; Horiike, Hiroshi*
JAERI-Tech 2005-006, 116 Pages, 2005/03
JAERI-Tech-2005-006.pdf:24.79MB
no abstracts in English
Kim, S.-W.*; Kim, D.-H.*; Tanigawa, Hiroyasu; Hirose, Takanori; Koyama, Akira*; Narui, Minoru*
no journal, ,
no abstracts in English
Miwa, Shuhei; Donomae, Takako; Hinoki, Tatsuya*
no journal, ,
no abstracts in English
Miwa, Shuhei; Donomae, Takako; Hinoki, Tatsuya*
no journal, ,
no abstracts in English
Donomae, Takako; Miwa, Shuhei; Park, J. S.*; Hinoki, Tatsuya*
no journal, ,
Characteristics of the composite fuel assembly for the high burn-up fuel for the gas cooled fast breeder reactor were evaluated. By observing the microstructure from the viewpoint of the interface between SiC matrix in composite fuel assembly and buffer material, it became clear that there was the correlation between auxiliary segregation situation and strength characteristic. In addition, SiC matrix after the intensity test was also examined on the relation between microstructure and stress loading situation. As the result, there was the correlation in the growth agree with of existence and crystal grain of the stress loading.
Nozawa, Takashi; Park, J.-S.*; Tanigawa, Hiroyasu; Koyama, Akira*
no journal, ,
For evaluation on quasi-ductile SiC/SiC composites with failure behavior with irreversible energy consumption, determining a criterion for the failure initiation is important. This study aims to develop a methodology to evaluate failure strength using notched specimens. Results of double-notch tensile tests indicate notch insensitivity of SiC/SiC composites regardless of specimen size. This implies unique failure strength regardless of the presence of notches, giving a good correlation between the strength and energy in composite failure.
Tanigawa, Hiroyasu; Nakata, Toshiya*; Kim, D.-H.*; Ando, Masami; Shiba, Kiyoyuki; Hirose, Takanori; Komazaki, Shinichi*; Kono, Yutaka*; Koyama, Akira*
no journal, ,
Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems, as they have been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. F82H (Fe-8Cr-2W-V, Ta) is the RAFM which is designed with emphasis on high temperature property and weldablility. Fusion blanket system will be suffer from high temperature/high pressure of its coolant, heat flux of fusion plasma etc., which cause creep and fatigue load on blanket system. On the other hand, the current blanket system design have complicated structure to achieve its function, and require long weld to fabricate its structure. In this paper, unirradiated creep and fatigue properties of base metal and weldments of F82H will be reviewed, and critical issues for design will be discussed.
Nozawa, Takashi; Choi, Y.-B.*; Hinoki, Tatsuya*; Tanigawa, Hiroyasu
no journal, ,
no abstracts in English
Kikuchi, Mitsuru; Takizuka, Tomonori*
no journal, ,
Based on the recent main plasma transport, divertor power and particle physics, its implication will be discussed for the future fusion reactor. Especially, physical meaning of narrow SOL width in H-mode will be discussed.
Kikuchi, Mitsuru; Nagasaki, Kazunobu*; Shaing, K.*
no journal, ,
Analytical formula on effect of impurity toroidal viscosity on offset toroidal rotation is given. Non ambipolar flux of impurity is included and the solution is obtained by successive approximation.
