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Lu, K.; Takamizawa, Hisashi; Li, Y.; Masaki, Koichi*; Takagoshi, Daiki*; Nagai, Masaki*; Nannichi, Takashi*; Murakami, Kenta*; Kanto, Yasuhiro*; Yashirodai, Kenji*; et al.
Mechanical Engineering Journal (Internet), 10(4), p.22-00484_1 - 22-00484_13, 2023/08
Li, Y.; Katsumata, Genshichiro*; Masaki, Koichi; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Journal of Pressure Vessel Technology, 143(4), p.041501_1 - 041501_8, 2021/08
Times Cited Count:3 Percentile:23.50(Engineering, Mechanical)Li, Y.; Hirota, Takatoshi*; Itabashi, Yu*; Yamamoto, Masato*; Kanto, Yasuhiro*; Suzuki, Masahide*; Miyamoto, Yuhei*
JAEA-Review 2020-011, 130 Pages, 2020/09
For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in Japan Atomic Energy Agency based on the latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressure thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to perform verification activities, and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL module and the source program of PASCAL was released to the members of working group. This report summarizes the activities of the working group on the verification of PASCAL in FY2016 and FY2017.
Lu, K.; Katsuyama, Jinya; Li, Y.; Miyamoto, Yuhei*; Hirota, Takatoshi*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Mechanical Engineering Journal (Internet), 7(3), p.19-00573_1 - 19-00573_14, 2020/06
Lu, K.; Katsuyama, Jinya; Li, Y.; Miyamoto, Yuhei*; Hirota, Takatoshi*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 9 Pages, 2019/05
Li, Y.; Katsumata, Genshichiro*; Masaki, Koichi*; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 10 Pages, 2017/07
In Japan, a PFM analysis code PASCAL (PFM Analysis of Structural Components in Aging LWR) has been developed by the Japan Atomic Energy Agency to evaluate the through-wall cracking frequencies of Japanese reactor pressure vessels (RPVs) considering neutron irradiation embrittlement and pressurized thermal shock transients. In this study, as a part of the verification activities, a working group was established in Japan, with seven organizations from industry, universities and institutes voluntarily participating as members. The source program of PASCAL was released to the members of the working group. Through one year activities, the applicability of PASCAL for structural integrity assessments of domestic RPVs was confirmed with great confidence. This paper presents the details of the verification activities of the working group including the verification plan, approaches and results.
Li, Y.; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Kanto, Yasuhiro*; Suzuki, Masahide*; Masaki, Koichi*
JAEA-Review 2017-005, 80 Pages, 2017/03
For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in JAEA based on latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressurized thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to verify the probabilistic variables, functions and models incorporated in the PASCAL and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL3 which is a PFM analysis module of PASCAL, and the source program of PASCAL3 was released to the members of working group. Through one year activities, the applicability of PASCAL in structural integrity assessments of domestic RPVs was confirmed with great confidence. This report summarizes the activities of the working group on the verification of PASCAL in FY2015.
Kanto, Yasuhiro*; Onizawa, Kunio; Osakabe, Kazuya*; Yoshimura, Shinobu*
Proceedings of 10th International Workshop on the Integrity of Nuclear Components (ASINCO-10), p.189 - 194, 2014/04
The international Round Robin (RR) activity was performed in PFM sub-committees in JWES in conjunction with Korea and Taiwan research groups. The purposes of this program were to establish reliable procedures to evaluate fracture probability of reactor pressure vessels during pressurized thermal shock and to maintain the continuous cooperation among Asian institutes in the probabilistic approach to nuclear safety. The results of this work were summarized at the previous ASINCO workshop in 2010. Here, as the phase 2 of the program, a new international round robin activity is planned. This paper describes the outline of the problem. The aims of the program and the matters to be noticed is presented.
Kanto, Yasuhiro*; Jhung, M.*; Ting, K.*; He, Y.*; Onizawa, Kunio; Yoshimura, Shinobu*
International Journal of Pressure Vessels and Piping, 90-91, p.46 - 55, 2012/02
Times Cited Count:15 Percentile:67.94(Engineering, Multidisciplinary)The International Round Robin (RR) activity was performed by the Probabilistic Fracture Mechanics (PFM) sub-committees of the Atomic Energy Research Committee of the Japan Welding Engineering Society (JWES) in conjunction with Korean, Taiwanese and Chinese research groups. The purposes of this program are to establish reliable procedures for evaluating the fracture probability of reactor pressure vessels (RPVs) during pressurized thermal shock (PTS) and to maintain the continuous cooperation among Asian institutes in the probabilistic approach to nuclear safety. This paper describes the outline of the problems and summarizes the results from all participant countries. The RR activity consists of two parts; deterministic analyses on stress and temperature in the reactor pressure vessel wall during PTS, and probabilistic analyses on vessel fracture probability due to PTS transients. The differences caused by the selection of analyzing programs and some input parameters are discussed.
Onizawa, Kunio; Kanto, Yasuhiro*; Yoshimura, Shinobu*
Proceedings of 8th International Workshop on the Integrity of Nuclear Components 2010, p.137 - 146, 2010/04
The international Round Robin (RR) activity was established in PFM sub-committee in the Japan Welding Engineering Society. This paper summarizes the results from six Japanese participants in the international RR on probabilistic fracture mechanics (PFM) analyses on reactor pressure vessel integrity during pressurized thermal shock (PTS). The RR activity consists of two parts; deterministic analysis on temperature and stress during PTS, and probabilistic analysis on vessel fracture probability. The results from deterministic analysis by five participants were agreed well with among others. One exceptional case was calculation results based on a newly-developed finite difference method. For probabilistic analysis all participants used the same PFM analysis code PASCAL2. Results from five participants were compared with regard to the effects of inspection performance, Cu content and initial reference temperature on fracture probability. The results gave a reasonable agreement although slight differences among participants were found. The differences caused by the selection of some inputs and simulation method are discussed.
Kanto, Yasuhiro*; Onizawa, Kunio; Machida, Hideo*; Isobe, Yoshihiro*; Yoshimura, Shinobu*
International Journal of Pressure Vessels and Piping, 87(1), p.11 - 16, 2010/01
Times Cited Count:11 Percentile:61.34(Engineering, Multidisciplinary)JAEA had sponsored research committees on probabilistic fracture mechanics (PFM) organized by the Japan Welding Engineering Society (JWES) for more than a decade. This work still continues with the same members in JWES. The purpose of the continuous activity is to provide probabilistic approaches in several fields of integrity problems of nuclear power plant. This paper shows some of the newest results of the JWES research committee. First topic is evaluation of the new JSME code case with rules of fitness-for-service from the view of PFM, including reactor pressure vessel subject to pressurized thermal shock loading, piping with a crack of the allowable size and effect of sizing accuracy for piping integrity. Another is development of new PFM techniques including reliability assessment of piping with domestic SCC data and maintenance optimization of LWRs based on risk and economic models. The last topic is the international round robin program just starting from 2008.
Kanto, Yasuhiro*; Onizawa, Kunio; Machida, Hideo*; Isobe, Yoshihiro*; Yoshimura, Shinobu*
Proceedings of 7th International Conference on the Integrity of Nuclear Components, p.219 - 228, 2008/07
This paper describes a review of recent Japanese activities on probabilistic fracture mechanics (PFM) analyses. JAEA had sponsored research committees on PFM organized by the Japan Society of Mechanical Engineers and the Japan Welding Engineering Society (JWES) for more than a decade. This work still continues with the same members in JWES. The purpose of the continuous activity is to provide probabilistic approaches in several fields of integrity of reactor components. This paper summarizes some of the latest results of this activity. First topic is evaluation of the JSME rules on Fittness-For-Service from the view of PFM, including reactor pressure vessel with a crack of the allowable size, and effect of sizing accuracy in inspection. The next one is development of new PFM techniques including piping reliability assessment on domestic SCC data and maintenance optimization based on risk and economic models. The last is the international round robin program just starting from 2008.
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
Shibata, Katsuyuki; Onizawa, Kunio; Li, Y.*; Kanto, Yasuhiro*; Yoshimura, Shinobu*
Nihon Kikai Gakkai M&M 2003 Zairyo Rikigaku Bumon Koenkai Koen Rombunshu, No.03-11, p.939 - 940, 2003/00
no abstracts in English
Kanto, Yasuhiro*; Onizawa, Kunio; Yoshimura, Shinobu*
no journal, ,
In this paper, Japanese research activities on probabilistic fracture mechanics (PFM) are introduced; which purpose is to provide probabilistic approaches in several fields of integrity problems for the reactor components in nuclear power plants. The research activities include the evaluation of the new JSME code case with rules of Fitness-For-Service from the view of PFM, including reactor pressure vessel subject to pressurized thermal shock loading, so on. The international round robin analysis on probabilistic fracture mechanics conducted with a nuclear power advanced nations in Asia, Korea, Taiwan and China, is also presented as well as future research plan.
Kanto, Yasuhiro*; Onizawa, Kunio; Yoshimura, Shinobu*
no journal, ,
The international Round Robin (RR) activity on probabilistic fracture mechanics (PFM) analysis was performed in conjunction with Korea, Taiwan and Chinese research groups. The purposes of this program are to achieve the enhancement of PFM analysis technology and to maintain the continuous cooperation among Asian institutes in this field. The common problem for round robin was set to the evaluation of fracture probability of reactor pressure vessels during pressurized thermal shock event. This paper describes the outline of the problem and typical analysis results on the crack detection ability in in-service inspection. The importance in PFM analysis techniques and status in the participating countries are shown.