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Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.
Transactions of 26th International Conference on Structural Mechanics in Reactor Technology (SMiRT-26) (Internet), 10 Pages, 2022/07
In order to improve the seismic probabilistic risk assessment method, the authors are developing methods related to realistic response, realistic resistance and fragility assessment for buildings and equipment that are important for seismic safety. In this study, in order to identify of building damage mode subjected to large seismic motions, pushover analyses using multiple analysis codes were performed using a 3D FE model of a reactor building. We obtained the analysis results for the identification of local damage mode that contributes to the fragility assessment. In this paper, we report the progress of local damage mode and ultimate strength of the building by the pushover analysis. We also compared this result with the seismic response analysis results.
Choi, B.; Nishida, Akemi; Kawata, Manabu; Shiomi, Tadahiko; Li, Y.
JAEA-Research 2021-017, 174 Pages, 2022/03
JAEA-Research-2021-017.pdf:9.33MB
Standard methods such as lumped mass models have been used in the assessment of seismic safety and the design of building structures in nuclear facilities. Recent advances in computer capabilities allow the use of three-dimensional finite element (3D FE) models to account for the 3D behavior of buildings, material nonlinearity, and the nonlinear soil-structure interaction effect. Since the 3D FE model enables more complex and high-level treatment than ever before, it is necessary to ensure the reliability of the analytical results generated by the 3D FE model. Guidelines for assuring the dependability of modeling techniques and the treatment of nonlinear aspects of material properties have already been created and technical certifications have been awarded in domains other than nuclear engineering. The International Atomic Energy Agency performed an international benchmark study in nuclear engineering. Multiple organizations reported on the results of seismic response studies using the 3D FE model based on recordings from the Niigata-ken Chuetsuoki Earthquake in 2007. The variation in their analytical results was significant, indicating an urgent need to improve the reliability of the analytical results by standardization of the analytical methods using 3D FE models. Additionally, it has been pointed out that it is necessary to understand the 3D behavior in the seismic fragility assessment of buildings and equipment, which requires evaluating the realistic nonlinear behavior of building facilities when assessing their seismic fragility. In view of these considerations, a standard guideline for the seismic response analysis method using a 3D FE model was produced by incorporating the latest knowledge and findings in this area. The purpose of the guideline is to improve the reliability of the seismic response analysis method using 3D FE model of reactor buildings. The guideline consists of a main body, commentaries, and appendixes; it also provides standard procedures
Ichihara, Yoshitaka*; Nakamura, Naohiro*; Moritani, Hiroshi*; Horiguchi, Tomohiro*; Choi, B.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(1), p.1 - 14, 2022/03
In this study, we aim to approximately evaluate the effect of nonlinearity of reinforced concrete structures through seismic response analysis using the equivalent linear analysis method. A simulation analysis was performed for the ultimate response test of the shear wall of the reactor building used in an international competition by OECD/NEA in 1996. The equivalent stiffness and damping of the shear wall were obtained from the trilinear skeleton curves proposed by the Japan Electric Association and the hysteresis curves proposed by Cheng et al. The dominant frequency, maximum acceleration response, maximum displacement response, inertia force-displacement relationship, and acceleration response spectra of the top slab could be simulated well up to a shear strain of approximately 
=2.0
10
. The equivalent linear analysis used herein underestimates the maximum displacement response at the time of ultimate fracture of approximately =4.010. Moreover, the maximum shear strain of the shear wall could not capture the locally occurring shear strain compared with that of the nonlinear analysis. Therefore, when employing this method to evaluate the maximum shear strain and test results, including those during the sudden increase in displacement immediately before the fracture, sufficient attention must be paid to its applicability.
Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.
Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 7 Pages, 2021/08
In the seismic safety assessment of building structures in nuclear facilities, lumped mass models are conventionally used. However, they cannot possess the required high-accuracy evaluation of nuclear facilities, such as the local response at the equipment location in a reactor building. In this point of view, a seismic response analysis method using a three-dimensional finite element (3D FE) model is indispensable. Although, it has been reported that the analysis results obtained using 3D FE models vary greatly depending on the experience and knowledge of analysts, the quality of analysis results should be insured by developing a standard analysis method. In the Japan Atomic Energy Agency, we have developed a guideline for seismic response analysis methods that adopt 3D FE models of reactor buildings. The guideline consists of a main body, commentary, and several supplements; it also includes procedures, recommendations, points of attention, and a technical basis for conducting seismic response analysis using 3D FE models of reactor buildings. In this paper, the outline of the guideline and analysis examples based on the guideline are presented.
Choi, B.; Nishida, Akemi; Muramatsu, Ken*; Takada, Tsuyoshi*
Nihon Jishin Kogakkai Rombunshu (Internet), 20(2), p.2_1 - 2_16, 2020/02
no abstracts in English
Choi, B.; Nishida, Akemi; Muramatsu, Ken*; Takada, Tsuyoshi*
Proceedings of 12th International Conference on Structural Safety & Reliability (ICOSSAR 2017) (USB Flash Drive), p.2206 - 2213, 2017/08
In order to clarify the influence of the difference of modeling method on the variation of the result of seismic response analysis of nuclear facility, seismic response analysis using various simulated input ground motions was carried out and the sensitivity analyses of the variations in seismic response was conducted. In particular, we focused on the maximum acceleration response of reactor building shear walls, the effect of modeling method on response result and the factors of response variation were described and discussed.
Takeda, Nobukazu; Shibanuma, Kiyoshi
Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.988 - 990, 2004/11
The simplified analytical model of the support structure composed of complicated structures such as multiple flexible plates was proposed for the dynamic analysis of the ITER major components of VV and TF coil. The support structure composed of flexible plates and connection bolts was modeled as a spring model composed of only two spring elements including the effect of connection bolts. The stiffness of both spring models for VV and TF coil agree well with that of shell models simulating actual structures such as flexible plates and connection bolts. Using the proposed model, the dynamic analysis of the VV and TF coil for the ITER were performed to estimate the integrity under the design earthquake at Rokkasho, a candidate of ITER site. As a result, it is found that the maximum relative displacement of 8.6 mm between VV and TF coil is much less than 100 mm, so that the integrity of the major components are ensured for the expected earthquake event.
Uchiyama, Tomoaki; Oikawa, Tetsukuni; Kondo, Masaaki; Watanabe, Yuichi*; Tamura, Kazuo*
JAERI-Data/Code 2002-011, 205 Pages, 2002/03
JAERI-Data-Code-2002-011.pdf:8.52MB
This report is a user's manual of seismic system reliability analysis code SECOM2 developed at the JAERI for system reliability analysis, which is one of the tasks of seismic probabilistic safety assessment (PSA) of nuclear power plants (NPPs). The SECOM2 code has many functions such as calculation of component and system failure probabilities for given seismic motion levels at the site of an NPP based on the response factor method, calculation of accident sequence frequencies and the core damage frequency (CDF), importance analysis using various indicators, uncertainty analysis, and calculation of the CDF taking into account the effect of the correlations of responses and capacities of components. These analyses require the fault tree (FT) representing the occurrence condition of the system failures and core damage, information about responses and capacities of the components which compose the FT, and seismic hazard curve for the NPP site as input. This report presents calculation method used in the SECOM2 code and how to use those functions in the SECOM2 code.
JAERI 1322, 157 Pages, 1991/04
no abstracts in English
JAERI-M 90-003, 129 Pages, 1990/02
no abstracts in English
; *
Nihon Genshiryoku Gakkai-Shi, 27(2), p.145 - 158, 1985/00
Times Cited Count：2 Percentile：37.64(Nuclear Science & Technology)no abstracts in English
;
Nucl.Eng.Des., 60, p.297 - 309, 1980/00
Times Cited Count：2 Percentile：33.89(Nuclear Science & Technology)no abstracts in English
JAERI-M 8273, 38 Pages, 1979/06
no abstracts in English
JAERI-M 5166, 29 Pages, 1973/02
no abstracts in English
Morishita, Masaki; Otani, Akihito*
no journal, ,
The JSME Code Case N-CC-008 provides design rules for piping seismic design by inelastic response analysis and strain-based fatigue criteria. The Code Case uses the Rainflow method for cycle counting. The Rainflow method is used for identifying pairs of peaks/valleys of the representative strain and their occurrence times. On the other hand, ASME Code reads "The Rainflow cycle counting method is recommended but not applicable for non-proportional loading." The authors analyzed the behavior of multi-axial strain of piping systems to test the non-proportionality. The analysis results showed that the multi-axial strain in piping systems induced by seismic excitation is almost proportional. Based on this result, the authors concluded that the Rainflow cycle counting method is well applicable for the piping seismic fatigue evaluation. In addition to these numerical analyses with the IS method, some discussions are also made in this paper from the viewpoint of the relation between vibration mode and strain components to support the conclusion that the piping strain by seismic loads is proportional.
Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.
no journal, ,
no abstracts in English
