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Chikhray, Y.*; Kulsartov, T.*; Shestakov, V.*; Kenzhina, I.*; Askerbekov, S.*; Sumita, Junya; Ueta, Shohei; Shibata, Taiju; Sakaba, Nariaki; Abdullin, Kh.*; et al.
Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.572 - 577, 2016/11
Application of SiC as corrosion-resistive coating over graphite remains important task for HTGR. This study presents the results of chemical interaction of the SiC gradient coating over the high-density IG-110 graphite with water vapor in the temperature up to 1673 K. The experiments at 100 Pa of water vapor showed that the passive reaction caused to form SiO
film on the surface of SiC coating. Active corrosion of SiC in 1Pa of water vapor leads to deposits of various carbon composites on its surface.
Shimazaki, Yosuke; Isaka, Kazuyoshi; Nomoto, Yasunobu; Seki, Tomokazu; Ohashi, Hirofumi
JAEA-Technology 2014-038, 51 Pages, 2014/12
JAEA-Technology-2014-038.pdf:3.84MB
The analytical models for the evaluation of graphite oxidation were implemented into the THYTAN code, which employs the mass balance and a node-link computational scheme to evaluate tritium behavior in the High Temperature Gas-cooled Reactor (HTGR) systems for hydrogen production, to analyze the graphite oxidation during the air or water ingress accidents in the HTGR systems. This report describes the analytical models of the THYTAN code in terms of the graphite oxidation analysis and its verification and validation (V&V) results. Mass transfer from the gas mixture in the coolant channel to the graphite surface, diffusion in the graphite, graphite oxidation by air or water, chemical reaction and release from the primary circuit to the containment vessel by a safety valve were modeled to calculate the mass balance in the graphite and the gas mixture in the coolant channel. The computed solutions using the THYTAN code for simple questions were compared to the analytical results by a hand calculation to verify the algorithms for each implemented analytical model. A representation of the graphite oxidation experimental was analyzed using the THYTAN code, and the results were compared to the experimental data and the computed solutions using the GRACE code, which was used for the safety analysis of the High Temperature Engineering Test Reactor (HTTR), in regard to corrosion depth of graphite and oxygen concentration at the outlet of the test section to validate the analytical models of the THYTAN code. The comparison of THYTAN code results with the analytical solutions, experimental data and the GRACE code results showed the good agreement.
Ueta, Shohei; Sumita, Junya; Shibata, Taiju; Aihara, Jun; Fujita, Ichiro*; Ohashi, Jun*; Nagaishi, Yoshihide*; Muto, Takenori*; Sawa, Kazuhiro; Sakaba, Nariaki
Nuclear Engineering and Design, 271, p.309 - 313, 2014/05
Times Cited Count：9 Percentile：57.01(Nuclear Science & Technology)A new concept of the high temperature gas-cooled reactor (HTGR) is proposed as a challenge to assure no event sequences to the harmful release of radioactive materials even when the design extension conditions (DECs) occur by deterministic approach based on the inherent safety features of the HTGR. The air/water ingress accident, one of the DECs for the HTGR, is prevented by additional measures (e.g. facility for suppression to air ingress). With regard to the core design, it is important to prevent recriticality accidents by keeping the geometry of the fuel rod which consists of the graphite sleeve, fuel compact and SiC-TRISO (TRIstructural-ISOtropic) coated fuel particle, and by improving the oxidation resistance of the graphite when air/water ingress accidents occur. Therefore, it is planned to develop the oxidation-resistant graphite, which is coated with gradient SiC layer. It is also planned that the experimental identification of the condition to form the stable oxide layer (SiO) for SiC layer on the oxidation-resistant graphite and on the SiC-TRISO fuel. This paper describes the R&D plan for un-irradiation and irradiation test under simulating air/water ingress accident condition to develop oxidation-resistant graphite and to investigate the oxidation behavior of SiC coated fuel particle.
C from irradiated graphite materials, 1; Oxidation behaviors and the changes in pore structure of Q1 and IG-110 graphite due to the air reaction (Joint research)Fujii, Kimio
JAERI-Tech 2005-048, 108 Pages, 2005/09
JAERI-Tech-2005-048.pdf:25.05MB
The graphite-moderated power reactor was shut down in 1998 and its decommissioning program is being planned. Various graphites are used in the core of magnox-type reactors and HTTR as core-support structural materials and moderating materials of fast neutrons. For the nuclear graphite disposal, it is necessary to determine especially the treatment of long-lived nuclides, such as C which are generated in the graphite components during reactor operation. As a research, which solves the problem of the C concentration, the cooperative research is concluded between JAERI and Japan Nuclear Power Corp. in 1999, and the research for the basic data acquisition has been advanced up to the present. To find the optimum conditions for C reduction, basic data on oxidation reaction and the structure of graphite materials are indispensable. In the present experiment, we measure the air oxidation characteristics in the temperature range 450
800
C in Quality1 graphite and IG-110 graphite. Changes in pore diameter and pore size distribution due to air oxidation are discussed.
Nath, K. G.; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Baba, Yuji
Applied Surface Science, 234(1-4), p.234 - 239, 2004/07
Times Cited Count：7 Percentile：37.61(Chemistry, Physical)Here we report oxidization properties of Si nanostructures grown on graphite. Si 1s X-ray photoemission spectra using synchrotron radiation are used in order to understand the oxidization pathways. Several Si films, such as 0.4, 2, 5.5 & Aring; were grown on highly oriented pyrolitic graphite (HOPG). In the case of a 0.4 & Aring; Si on HOPG, where different types of Si nanostructures in the form of nanoclusters are present, oxygen reactivity is nearly zero. In contrast, the thick film (5.5 & Aring;), where a bulk-type phase is present, shows a higher degree of reactivity. The results are discussed on the basis of nanostructure geometry, number of constituting Si atoms and cluster size.
Shibata, Taiju; Ishihara, Masahiro
Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2003 (ATEM '03) (CD-ROM), 5 Pages, 2003/09
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
Ishihara, Masahiro; Shibata, Taiju
Dai-4-Kai Kozobutsu No Anzensei, Shinraisei Ni Kansuru Kokunai Shimpojiumu Koen Rombunshu, p.101 - 108, 2000/00
no abstracts in English
Fujii, Kimio
JAERI-Research 99-050, 99 Pages, 1999/08
JAERI-Research-99-050.pdf:5.37MB
no abstracts in English
Ishihara, Masahiro; Iyoku, Tatsuo; Futakawa, Masatoshi
Nucl. Eng. Des., 148, p.91 - 100, 1994/00
Times Cited Count：4 Percentile：42.34(Nuclear Science & Technology)no abstracts in English
Ishihara, Masahiro; Iyoku, Tatsuo; Futakawa, Masatoshi
Zairyo, 42(472), p.15 - 21, 1993/01
no abstracts in English
Fujii, Kimio; Nakano, Junichi; Shindo, Masami
Journal of Nuclear Materials, 203, p.10 - 16, 1993/00
Times Cited Count：16 Percentile：80.76(Materials Science, Multidisciplinary)no abstracts in English
Fujii, Kimio; Nomura, Shinzo; *; Shindo, Masami
Journal of Nuclear Materials, 187, p.32 - 38, 1992/00
Times Cited Count：7 Percentile：57.42(Materials Science, Multidisciplinary)no abstracts in English
Fujii, Kimio; *; Nomura, Shinzo; Shindo, Masami
Journal of Nuclear Materials, 187, p.204 - 208, 1992/00
Times Cited Count：13 Percentile：74.71(Materials Science, Multidisciplinary)no abstracts in English
*; Ohashi, Kazutaka*; Iyoku, Tatsuo
FAPIG, 0(129), p.13 - 21, 1991/11
no abstracts in English
Eto, Motokuni; Oku, Tatsuo; Konishi, Takashi*
Carbon, 29(1), p.11 - 21, 1991/01
Times Cited Count：24 Percentile：73.73(Chemistry, Physical)no abstracts in English
Iyoku, Tatsuo; Shiozawa, Shusaku; Ishihara, Masahiro; ; Oku, Tatsuo*
Nucl. Eng. Des., 132, p.23 - 30, 1991/00
Times Cited Count：23 Percentile：89.72(Nuclear Science & Technology)no abstracts in English
;
Journal of Nuclear Materials, 151, p.202 - 208, 1988/00
Times Cited Count：2 Percentile：31.31(Materials Science, Multidisciplinary)no abstracts in English
; ;
Nihon Genshiryoku Gakkai-Shi, 29(7), p.651 - 655, 1987/07
Times Cited Count：7 Percentile：60.01(Nuclear Science & Technology)no abstracts in English
; ; ;
JAERI-M 87-056, 49 Pages, 1987/03
no abstracts in English
