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Narukawa, Takafumi; Yamaguchi, Akira*; Jang, S.*; Amaya, Masaki
Journal of Nuclear Materials, 499, p.528 - 538, 2018/02
Times Cited Count：9 Percentile：58.49(Materials Science, Multidisciplinary)Sugino, Hideharu*; Ito, Hiroto*; Onizawa, Kunio; Suzuki, Masahide
Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(4), p.233 - 241, 2005/12
The purpose of this research is to establish the reliability evaluation method of aged nuclear power components for seismic events from a viewpoint of long-term use of the existing light water reactor nuclear power plants. For this purpose, we developed a piping failure probability evaluation code "PASCAL-SC" based on probabilistic fracture mechanics, and a probabilistic seismic hazard evaluation code "SHEAT-FM" for calculating the seismic occurrence probability of a plant site, paying attention to aging such as fatigue crack progress by the stress corrosion cracking and seismic load in primary coolant piping system. We proposed the reliability evaluation method of aged piping for seismic events by combination of these codes. Using this method, we evaluated the reliability of a weld line in the PLR(Primary Loop Recirculation system) piping of the BWR model plant for seismic events.
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kato, Daisuke*
International Journal of Pressure Vessels and Piping, 81(9), p.749 - 756, 2004/09
Times Cited Count：5 Percentile：33.31(Engineering, Multidisciplinary)The paper describes the procedure to evaluate the ductile crack extension, where an increase in fracture resistance by a ductile crack extension is considered. Two standard 
-resistance curves are prepared for applying the elasto-plastic fracture criterion. Case studies concerning the effect of elasto-plastic fracture criterion were carried out using a severe PTS transient. The introduction of the elasto-plastic fracture criterion significantly contributes to remove the over-conservatism in applying the linear elastic fracture criterion. It was also found that the algorithm of the re-evaluation of crack tip characterization also has a significant effect on the failure probability.
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kanto, Yasuhiro*; Yoshimura, Shinobu*
Pressure Vessel and Piping Codes and Standards (PVP-Vol.480), p.235 - 242, 2004/00
A screening standard of small flaws that have no significant influence on the structural integrity is prescribed in ASME Code Sec.XI. From the viewpoint of probabilistic methodology, there are some concerns that weather or not the failure probability is uniform for flaws with various aspect ratios and failure frequencies are small enough. Moreover, acceptable flaws may be determined more rationally based the failure probability. A study was performed on the failure probability of RPVs with a surface flaw specified in Sec.XI using the PFM code PASCAL. A PTS transient of NRC/EPRI Benchmark Study was used. Analysis results showed that the conditional failure probability of a RPV with an initial flaw of acceptable depth depended on the aspect ratio. For a circular flaw, the failure probability is high due to the increase in crack initiation at the surface point. The maximum difference in failure probability reaches one order of magnitude. A case study for determining the acceptable flaws based on failure probability was also carried out.
Shibata, Katsuyuki; Kanto, Yasuhiro*; Yoshimura, Shinobu*; Yagawa, Genki*
Proceedings of 5th International Workshop on the Integrity of Nuclear Components, p.99 - 117, 2004/00
no abstracts in English
Hanawa, Satoshi; Ishihara, Masahiro; Shibata, Taiju
Transactions of 17th International Conference on Structural Mechanics in Reactor Technology (SMiRT-17) (CD-ROM), 6 Pages, 2003/08
From a viewpoint of advanced design method of graphite components, it is important to apply the realistic fracture model in the design method. The applicability of the microstructure based brittle fracture model under multiaxial stress condition was, therefore, investigated. The fracture model is possible to treat grain size as well as pore size with fracture mechanics approach taking account of the crystal structure of the graphite. The model was applied to the biaxial strength prediction of near isotropic nuclear graphite using grain/pore related microstructural parameters. Prediction results were compared with biaxial strength data obtained by simultaneous loadings of inner pressure and longitudinal load with thin-walled cylindrical specimen. From this study, it was found that the fracture model predicted fairly good not only mean strength but also strength distribution under biaxial stress condition, and it was concluded that the microstructure based brittle fracture model would be applicable as the advanced design method.
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kato, Daisuke*
Proceedings of 4th International Workshop on the Integrity of Nuclear Components, p.31 - 41, 2002/00
no abstracts in English
Ishihara, Masahiro; Takahashi, Tsuneo*; Hanawa, Satoshi
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kato, Daisuke*
JAERI-Data/Code 2001-011, 233 Pages, 2001/03
JAERI-Data-Code-2001-011.pdf:7.42MB
no abstracts in English
Li, Y.*; Kato, Daisuke*; Shibata, Katsuyuki
JSME International Journal, Series A, 44(1), p.130 - 137, 2001/01
no abstracts in English
Y.Li*; Kato, Daisuke*; Shibata, Katsuyuki
Proceedings of 7th International Conference on Nuclear Engineering (ICONE-7) (CD-ROM), 10 Pages, 1999/00
no abstracts in English
