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Yamaguchi, Yoshihito; Nishida, Akemi; Li, Y.
Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 7 Pages, 2022/07
The wall-thinning is one of the most important age-related degradation phenomena in nuclear piping systems. Furthermore, in recent years, several nuclear power plants in Japan have experienced severe earthquakes. Therefore, failure probability analysis and fragility evaluation of piping systems, taking both wall-thinning and seismic response stresses into consideration, have become increasingly important in seismic probabilistic risk assessment. In Japan Atomic Energy Agency, in order to evaluate the failure probability of aged piping system with wall-thinning, a probabilistic analysis code PASCAL-EC was developed. In this study, to evaluate the seismic fragility of a wall-thinned pipe, a model of seismic response stress considering the wall-thinning effect, a failure evaluation method for wall-thinned pipes, and functions related to uncertainties treatment for important influence parameters have been introduced to PASCAL-EC. In this paper, the improved PASCAL-EC is outlined and preliminary results of the seismic fragility evaluation performed using this code are provided.
Yamaguchi, Yoshihito; Li, Y.
Haikan Gijutsu, 63(12), p.22 - 27, 2021/10
no abstracts in English
Yamaguchi, Yoshihito; Katsuyama, Jinya; Masaki, Koichi*; Li, Y.
JAEA-Research 2020-017, 80 Pages, 2021/02
JAEA-Research-2020-017.pdf:3.5MB
The seismic probabilistic risk assessment (seismic PRA) is an important methodology to evaluate the seismic safety of nuclear power plants. Regarding seismic fragility evaluations performed in the seismic PRA, the Probabilistic Fracture Mechanics (PFM) can be applied as a useful evaluation technique for aged piping with crack or wall thinning due to the age-related degradation. Here, to advance seismic PRA methodology for the long-term operated nuclear power plants, a guideline for the fragility evaluation on the typical aged piping of nuclear power plants has been developed taking the aged-related degradation into account.
Yamaguchi, Yoshihito; Mano, Akihiro; Katsuyama, Jinya; Masaki, Koichi*; Miyamoto, Yuhei*; Li, Y.
JAEA-Data/Code 2020-021, 176 Pages, 2021/02
JAEA-Data-Code-2020-021.pdf:5.26MB
In Japan Atomic Energy Agency, as a part of researches on the structural integrity assessment and seismic safety assessment of aged components in nuclear power plants, a probabilistic fracture mechanics (PFM) analysis code PASCAL-SP (PFM Analysis of Structural Components in Aging LWR - Stress Corrosion Cracking at Welded Joints of Piping) has been developed to evaluate failure probability of piping. The initial version was released in 2010, and after that, the evaluation targets have been expanded and analysis functions have been improved based on the state-of-the art technology. Now, it is released as Ver. 2.0. In the latest version, primary water stress corrosion cracking in the environment of Pressurized Water Reactor, nickel based alloy stress corrosion cracking in the environment of Boiling Water Reactor, and thermal embrittlement can be taken into account as target age-related degradation. Also, many analysis functions have been improved such as incorporations of the latest stress intensity factor solutions and uncertainty evaluation model of weld residual stress. Moreover, seismic fragility evaluation function has been developed by introducing evaluation methods including crack growth analysis model considering excessive cyclic loading due to large earthquake. Furthermore, confidence level evaluation function has been incorporated by considering the epistemic and aleatory uncertainties related to influence parameters in the probabilistic evaluation. This report provides the user's manual and analysis methodology of PASCAL-SP Ver. 2.0.
Yamaguchi, Yoshihito; Katsuyama, Jinya; Li, Y.
Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 10 Pages, 2016/07
Oikawa, Tetsukuni; Fukushima, Seiichiro*; Takase, Hidekazu*; Uchiyama, Tomoaki*; Muramatsu, Ken
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
Ebine, Noriya; Yamaguchi, Yoshihito; Katsuyama, Jinya; Nishida, Akemi; Li, Y.
no journal, ,
A probabilistic analysis code PASCAL-EC (PFM Analysis of Structural Components in Aging LWR - Erosion and Corrosion) have been improved for evaluating structural integrity of wall thinned pipes on the basis of the Monte Carlo method. In order to perform the fragility evaluation for wall-thinned pipes, several functions are introduced to PASCAL-EC in this work, such as probabilistic evaluation model to consider the uncertainty of seismic response stress, a simple evaluation model to considered the increase of the seismic stress due to wall thinning and failure evaluation methods for wall-thinned pipes. This paper provides some details of these models and preliminary results of fragility evaluation using improved PASCAL-EC code for wall-thinned pipes in nuclear power plants.
Itoi, Tatsuya*; Nishida, Akemi; Takada, Tsuyoshi*; Hida, Takenori*; Sato, Hiroyuki
no journal, ,
This research aims to establish a probabilistic risk assessment method for high temperature gas-cooled reactors fully utilizing their design and safety characteristics. The presentation will explain achievements in the development of fragility analysis method.
