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Location
Lexington, Kentucky
Start Date
7-5-2026 11:00 AM
End Date
7-5-2026 11:30 AM
Description
Selection of appropriate seismic design ground motions remains a key challenge for seismic stability assessments of coal combustion residual (CCR) impoundment facilities, particularly where regulatory guidance does not specify a required hazard model. This paper examines the implications of using Uniform Hazard Spectra (UHS) derived from the 2014 versus the 2018 U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) for seismic amplification and stability evaluations of the Tennessee Valley Authority (TVA) Widows Creek Fossil (WCF) Plant CCR Management Units. The 2018 NSHM incorporates updated understanding of seismicity in the central and eastern United States and generally predicts higher ground motions than the 2014 model. To quantify the potential impact of this update, a simplified comparative stability assessment was performed using data from a previously analyzed TVA CCR facility with similar seismic setting and geometric characteristics. Results indicate that adoption of 2018 UHS-based motions leads to only marginal reductions in computed seismic stability for the representative case evaluated, with differences comparable to inherent modeling uncertainties. The findings suggest that use of the 2018 NSHM provides a more current and realistic representation of seismic hazard without materially altering stability conclusions for similar facilities, supporting its application in ongoing seismic assessments while maintaining the technical validity of prior evaluations based on the 2014 NSHM. Simplified assessment of existing structures under 2018 NSHM provides guidance to the asset owner to manage their assets for long term conditions and it is a very good baseline to determine if more complicated further analysis is needed or not.
Document Type
Presentation
Archival?
Archival
Included in
Energy Systems Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Simplified Approximate Procedure for Assessing the Implications of Updated USGS Seismic Hazard Models on Seismic Stability Assessments of CCR Impoundment Facilities
Lexington, Kentucky
Selection of appropriate seismic design ground motions remains a key challenge for seismic stability assessments of coal combustion residual (CCR) impoundment facilities, particularly where regulatory guidance does not specify a required hazard model. This paper examines the implications of using Uniform Hazard Spectra (UHS) derived from the 2014 versus the 2018 U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) for seismic amplification and stability evaluations of the Tennessee Valley Authority (TVA) Widows Creek Fossil (WCF) Plant CCR Management Units. The 2018 NSHM incorporates updated understanding of seismicity in the central and eastern United States and generally predicts higher ground motions than the 2014 model. To quantify the potential impact of this update, a simplified comparative stability assessment was performed using data from a previously analyzed TVA CCR facility with similar seismic setting and geometric characteristics. Results indicate that adoption of 2018 UHS-based motions leads to only marginal reductions in computed seismic stability for the representative case evaluated, with differences comparable to inherent modeling uncertainties. The findings suggest that use of the 2018 NSHM provides a more current and realistic representation of seismic hazard without materially altering stability conclusions for similar facilities, supporting its application in ongoing seismic assessments while maintaining the technical validity of prior evaluations based on the 2014 NSHM. Simplified assessment of existing structures under 2018 NSHM provides guidance to the asset owner to manage their assets for long term conditions and it is a very good baseline to determine if more complicated further analysis is needed or not.
