Seismic risk assessment for the CEUS nuclear power plant fleet based on the NGA-East ground motion model

2021 ◽  
pp. 875529302110246
Author(s):  
Mohamed M Talaat ◽  
Timothy J Graf ◽  
Abhinav Anup ◽  
Gregory S Hardy ◽  
John M Richards
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Nuclear Power ◽  
Assessment Tools ◽  
Specific Information ◽  
Valuable Insight ◽  
Motion Model ◽  
Ground Motion Model

Knowledge of seismic hazard at engineered facilities evolves with the growth in related technical fields. This presents challenges to stability and decision-making concerning safety that require effective assessment tools. Updated mean hazard estimates were developed at nuclear power plant (NPP) sites in Central and Eastern United States (CEUS) using the Next Generation Attenuation (NGA)-East ground motion model (GMM) and the latest available site amplification data. These estimates indicated that seismic hazard increases at several CEUS NPP sites, especially for spectral frequencies below 5 Hz. To assess the safety implications, updated mean seismic core damage frequency (SCDF) estimates were developed for the CEUS NPP fleet using the updated mean hazard estimates and updated plant-level fragilities (PLFs). The PLFs were developed from plant-specific information compiled by the U.S. Nuclear Regulatory Commission (USNRC) and recent seismic probabilistic risk assessments (SPRAs) completed by some NPPs. The SCDF quantification followed a method defined by the USNRC to combine risk contributions from different spectral frequencies. While not intended to provide a precise quantification of risk, such as that provided by a full SPRA, when the results are compared against other estimates using the same approach, this process provides valuable insight into the overall change in risk as the understanding of hazard changes. The assessment indicated no significant change in estimated risk for the majority of the CEUS fleet compared to the 2010 USNRC estimates—about 90% of the fleet risk distribution was lower, equal, or slightly higher. A few NPPs had SCDF estimates significantly larger than the 2010 estimates. The SCDF increases at these few NPPs have larger contributions from updated PLFs than updated hazard estimates. The majority of these NPPs have recently completed detailed SPRAs and have tools to develop more accurate estimates of the updated risk than can be achieved in this fleet-level study.

Simplified methods to estimate mean hazard due to updated ground motion model: Application to nuclear power plants in CEUS

2021 ◽  
pp. 875529302110074
Author(s):  
Mohamed M Talaat ◽  
Andrew Seifried ◽  
Abhinav Anup ◽  
Gregory S Hardy ◽  
John M Richards
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Nuclear Power ◽  
Power Plants ◽  
Site Response ◽  
Motion Model ◽  
Eastern United States ◽  
Logic Tree ◽  
Ground Motion Model ◽  
Good Agreement

Two methods were developed to estimate updated mean seismic hazard for existing probabilistic seismic hazard analyses (PSHAs) due to a change in the ground motion model (GMM). Both methods were used to estimate updated hazard at nuclear power plant (NPP) sites in the Central and Eastern United States (CEUS) for a change from the Electric Power Research Institute (EPRI) 2013 GMM to the Next Generation Attenuation (NGA)-East GMM. These methods present efficient tools to inform decisions on whether to perform a full PSHA revision or other detailed evaluations, especially when a large number of sites must be analyzed. A Simplified Hazard (SiHaz) method was developed to estimate mean hazard explicitly using a reduced PSHA logic tree that incorporates the updated GMM and potential changes in the site response model. An alternative scaling method was independently developed to be applied directly to current CEUS NPP hazard. Both methods were validated using updated PSHA results at several sites. Estimates at 46 NPP sites using both methods showed good agreement for mean annual frequencies of exceedance between 1E-4 and 1E-5/yr.

Research on Earthquake Acceleration Alarm of Nuclear Power Plant

2021 ◽  
Author(s):  
Li Liang ◽  
Pan Rong ◽  
Ren Guopeng ◽  
Zhu Xiuyun
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
False Alarm ◽  
Ground Motion ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Time History ◽  
Seismic Acceleration ◽  
Trigger Signal

Abstract Almost all nuclear power plants in the world are equipped with seismic instrument system, especially the third generation nuclear power plants in China. When the ground motion measured by four time history accelerometers of containment foundation exceeds the preset threshold, the automatic shutdown trigger signal will be generated. However, from the seismic acceleration characteristics, isolated and prominent single high frequency will be generated the acceleration peak, which has no decisive effect on the seismic response, may cause false alarm, which has a certain impact on the smooth operation of nuclear power plant. According to the principle of three elements of ground motion, this paper puts forward a method that first selects the filtering frequency band which accords with the structural characteristics of nuclear power plants, then synthesizes the three axial acceleration time history, and finally selects the appropriate acceleration peak value for threshold alarm. The results show that the seismic acceleration results obtained by this method can well represent the actual magnitude of acceleration, and can solve the problem of false alarm due to the randomness of single seismic wave, and can be used for automatic reactor shutdown trigger signal of seismic acceleration.

scholarly journals Probabilistic seismic hazard assessment for a new-build nuclear power plant site in the UK

2018 ◽  
Vol 17 (1) ◽  
pp. 1-36 ◽  
Author(s):  
Iain J. Tromans ◽  
Guillermo Aldama-Bustos ◽  
John Douglas ◽  
Angeliki Lessi-Cheimariou ◽  
Simon Hunt ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Hazard ◽  
Hazard Assessment ◽  
Nuclear Power ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Plant Site ◽  
The Uk

A Ground-Motion Logic-Tree Scheme for Regional Seismic Hazard Studies

2017 ◽  
Vol 33 (3) ◽  
pp. 837-856 ◽  
Author(s):  
Özkan Kale ◽  
Sinan Akkar
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Motion Prediction ◽  
Motion Model ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Logic Tree ◽  
Ground Motion Model ◽  
The One

We propose a methodology that can be useful to the hazard expert in building ground-motion logic trees to capture the center and range of ground-motion amplitudes. The methodology can be used to identify a logic-tree structure and weighting scheme that prevents the dominancy of a specific ground-motion model. This strategy can be useful for regional probabilistic seismic hazard since logic-trees biased by a specific ground-motion predictive model (GMPE) may cause disparities in the seismic hazard for regions represented by large number of sites with complex seismic features. The methodology first identifies a suit of candidate ground-motion prediction equations that can cover the center, body and range of estimated ground motions. The GMPE set is then used for establishing alternative logic-trees composed of different weighting schemes to identify the one(s) that would not be biased towards a particular GMPE due to its sensitivity to the weights. The proposed methodology utilizes visual and statistical tools to assess the ground motion distributions over large areas that makes it more practical for regional hazard studies.

Assessment of Aging of Nuclear Power Plant Civil Structures

2002 ◽  
Author(s):  
D. J. Naus ◽  
B. R. Ellingwood ◽  
H. L. Graves
Keyword(s):  
Reinforced Concrete ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Structural Reliability ◽  
Operating Experience ◽  
Assessment Tools ◽  
Background Information ◽  
Civil Structures ◽  
Age Related

Research is being conducted by ORNL for the USNRC to address aging of civil structures in light-water reactor plants. The importance and operating experience of nuclear power plant (NPP) civil structures is reviewed. Factors that can lead to age-related degradation of reinforced concrete structures and containment metallic pressure boundaries (i.e., steel containments and liners of reinforced concrete containments) are identified and their manifestations described. Background information and data for improving and developing methods to assess the effects of age-related degradation on structural performance are provided. Techniques for detection of degradation are reviewed and research related to development of methods for inspection of inaccessible regions of the containment pressure boundary presented. Application of structural reliability analysis methods to develop condition assessment tools and guidelines is described.

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