Extreme earthquake response of nuclear power plants isolated using sliding bearings

Kumar, Manish; Whittaker, Andrew S.; Constantinou, Michael C.

doi:10.1016/j.nucengdes.2017.02.030

Cited by 39 publications

(22 citation statements)

References 10 publications

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“…The UHRS was calculated for a return period of 10,000 years. Complete details on the ground motions are presented in Kumar et al 32 . One of the ground motions (NGA‐72, Lake Hughes, 1971 San Fernando earthquake) was used to generate response spectra at different locations and damping models.…”

Section: Seismic Hazardsupporting

confidence: 91%

Damping implementation issues for in‐structure response estimation of seismically isolated nuclear structures

Kumar

2021

Earthq Engng Struct Dyn

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Seismic (base) isolation of a nuclear power plant (NPP) is a viable strategy to reduce seismic demands in structural elements and nonstructural systems and components. Accurate estimation of in‐structure response of base‐isolated NPPs is critical to the analysis and design of safety‐related structural components. Damping models and their implementation in contemporary analysis platforms play a significant role in the numerical response estimation of a nonlinear system. Most of the recent damping studies cater to moment frame buildings for which nonlinearities are modeled using massless rotational springs. There are unique challenges associated with the implementation of damping to numerical models of the base‐isolated NPPs due to the broad frequency range of interest and the markedly different damping characteristics of the isolators and the superstructure. In‐structure response spectra of a base‐isolated NPP are sensitive to the chosen numerical and modeling techniques, both of which are investigated in this paper. Three representations of base‐isolated NPP are considered: (1) a two‐node macro model, (2) a lumped‐mass stick model, and (3) a detailed finite element model. Rayleigh damping, modal damping, uniform frequency damping, and several combinations thereof were used with the three NPP models to obtain the median response of the base‐isolated NPP subject to 30 sets of three‐dimensional ground excitations. The results allow informed decisions regarding the selection of a numerical model and damping implementation to different analysis platforms needed to obtain a reliable in‐structure response of base‐isolated NPPs subject to earthquake shaking.

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Section: Seismic Hazardsupporting

confidence: 91%

Damping implementation issues for in‐structure response estimation of seismically isolated nuclear structures

Kumar

2021

Earthq Engng Struct Dyn

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“…Finally, when none of the modes exhibit substantial vertical motion and yet the V component of GM is still required for RHA (e.g. stiff nuclear power plants as in Kumar et al (2017)), only one multicomponent Composite Spectrum (Equation 6) is needed for selecting multicomponent GMs.…”

Section: The Cms-uhs Composite Spectrummentioning

confidence: 99%

“…For many buildings, the horizontal (H) components of GM alone may be sufficient (Haselton et al, 2017; Pacific Earthquake Engineering Research Center: Tall Buildings Initiative, 2017) but for other structures (e.g. buildings with cantilevers, bridges, dams, nuclear power plants), the H components alone may be insufficient because the seismic response may be influenced significantly by the vertical (V) component of GM (see, for example, Bernier et al, 2016; Gülerce and Abrahamson, 2010; Harrington and Liel, 2016; Kumar et al, 2017). Therefore, conducting nonlinear RHAs of complex 3D structures requires the selection of input GMs that are consistent with respect to the hazard defined in terms of all three orthogonal components of GM.…”

Section: Introductionmentioning

confidence: 99%

“…cable-stayed bridges as in Figure 6 of Brownjohn and Xia (2000)). Second, the V component of GM can be selected as an afterthought by first selecting GMs considering the H component(s) alone and then choosing the V component of the corresponding record (Bernier et al, 2016; NEHRP Consultants Joint Venture, 2011) or selected by separately matching against the TS for the V component (American Society of Civil Engineers, 2016; Kumar et al, 2017). The latter approach contradicts with the fact that all components of a multicomponent GM should come from the same earthquake scenario 2 (Bommer et al, 2011), as all components are simultaneously applied in an RHA of a complex 3D structure.…”

Section: Introductionmentioning

confidence: 99%

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Selecting, scaling, and orienting three components of ground motions for intensity-based assessments at far-field sites

Kwong

Chopra

2020

Earthquake Spectra

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This article develops a methodology for selecting, scaling, and orienting three orthogonal components of ground motion (GM) when conducting intensity-based assessments of structures. Target spectra for selecting multicomponent GMs are critically examined and strategies for selecting hazard-consistent GMs are investigated. The Conditional Mean Spectrum–Uniform Hazard Spectrum (CMS-UHS) Composite Spectrum is proposed as an alternative to several Conditional Mean Spectra for selecting multicomponent GMs when conducting intensity-based assessments of complex three-dimensional (3D) structures. To ensure hazard consistency, multicomponent GMs should be selected using (a) the target spectrum for the vertical component of GM, (b) a wide range of vibration periods, and (c) scale factors that are constrained. With constrained scale factors, all three components of a GM can be reasonably scaled either by the same scale factor or by different scale factors.

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“…In response to these issues, various solutions have been proposed by researchers. Specifically, Kumar et al (2017) and Hu et al (2018) proposed using unfavorable earthquakes for BIS NPPs. This may protect BIS NPPs structures to a certain extern but increase the economic cost.…”

Section: Introductionmentioning

confidence: 99%

Innovation structure combining inter-story isolation with passive cooling effect for AP1000 nuclear power plants

Hou¹,

Liu

Wang³

et al. 2021

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PurposeAn inter-story isolation structure (IIS) for AP1000 nuclear power plants (NPPs) is provided to resolve the conflict of seismic safety and the optimal location of air intakes.Design/methodology/approachThe effect of passive cooling system (PCS) is better with lower altitude of air intakes than that in the original design of AP1000 NPPs. Seismic performances of IIS NPPs, including the seismic responses, damping frequency bandwidth and seismic reduction robustness, are improved by combining the position of air intakes lower and the optimal design method.FindingsTheoretical analysis and numerical simulation are illustrated that the seismic reduction failure of IIS NPPs is the lowest probability of occurrence when PCS has highest working efficiency.Originality/valueThe IIS NPPs can transfer the contradiction between PCS work efficiency and seismic safety of NPPs to the mutual promotion of them.

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Extreme earthquake response of nuclear power plants isolated using sliding bearings

Cited by 39 publications

References 10 publications

Damping implementation issues for in‐structure response estimation of seismically isolated nuclear structures

Damping implementation issues for in‐structure response estimation of seismically isolated nuclear structures

Selecting, scaling, and orienting three components of ground motions for intensity-based assessments at far-field sites

Innovation structure combining inter-story isolation with passive cooling effect for AP1000 nuclear power plants

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