ML22132A299
| ML22132A299 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2022 |
| From: | David Heeszel, Clifford Munson, Scott Stovall, Jacqueline Thompson, Thomas Weaver NRC/NRR/DEX, NRC/NRR/DEX/EXHB, NRC/RES/DE |
| To: | |
| Jenise Thompson 301-415-0381 | |
| References | |
| Download: ML22132A299 (30) | |
Text
Seismic Hazard Updates Cliff Munson, David Heeszel, Jenise Thompson NRR/DEX Scott Stovall, Thomas Weaver RES/DE May 17, 2022
Contents
- Background
- Overview of Process
- Example Site Implementation
- Screening
- Project Schedule
- References
- Questions
=
Background===
- In response to 10 CFR 50.54(f) request licensees developed updated seismic hazard curves and GMRS for each NPP
- CEUS NPP sites used CEUS-SSC and EPRI (2013) seismic models and SPID
- WUS NPP sites developed SSHAC L3 seismic models
- Most recent seismic hazard characterizations are found in NUREG/KM-017 published this year
- NRC staff re-evaluated site geology to develop updated GMRS
- Under the POANHI framework NRC staff is evaluating
- new seismic ground motion model NGA-East for the CEUS NPP sites
- Updated approaches from recent site response analyses SSHAC research project
POANHI Framework
- Ongoing staff effort to collect and integrate external hazard information for operating nuclear fleet
- Currently in the aggregation and assessment phases
POANHI Seismic Hazard Update
- Reference rock seismic hazard curves using CEUS/SSC and NGA-East
- Re-evaluate site response analyses to capture SSHAC Site Response Lessons Learned
- Expand logic tree to consider wider range of epistemic uncertainty
- Consider comments on NUREG/KM-017 geologic interpretations
- Control point hazard curves and GMRS
- Seismic hazard update report with data sets available in ADAMs
- Screening evaluation
Example Site Prioritization Savannah River Test Site Reference Rock Hazard and NUREG/KM-017 Site Response Analysis GMRS
Implementation of Seismic Source and Ground Motion Models and Site Response Analysis
- Run CEUS-SSC seismic source (NUREG 2115) models
- Extend radius for source zones out to 500 km
- Include repeated large magnitude sources out to 1000 km
- Run EPRI GMM (2013)
- Run NGA-East ground motion model (PEER, 2018)
- Convolve reference rock hazard with NUREG/KM-017 site response analysis to determine control point hazard and GMRS
Seismotectonic Zones CEUS-SSC + NGA-East
Mmax Zones CEUS-SSC + NGA-East
Repeated Large Magnitude Earthquakes Charleston Rift Zone Sources CEUS-SSC + NGA-East
NUREG/KM-017 Site Response Analysis SAF
GMRS Comparison Used for Prioritization
RG 1.174 Acceptance Guidelines
SCDF for Test Site
= 0.4 50 = 0.76 Calculate SCDF
- 1. EPRI-GMM control point hazard
- 2. NGA-East control point hazard
- 3. Convolve hazard with fragility curves for 1, 5 and 10 Hz
- 4. Average SCDF1Hz SCDF5Hz SCDF10Hz
Distribution of C50 and C Across the Fleet
50 = 0.55
= 0.4 Using GI-199 dataset
SCDF For Alternative C50 Values
= 0.4
Updated Site Response Analysis and PSHA Savannah River Test Site Updated Site Response Analysis and PSHA
Implementation of Latest Site Response Analyses Models and Methods
- For each CEUS NPP site develop site response logic tree that incorporates latest methods and models from SSHAC Site Response Project
- Overall lesson learned from SSHAC Site Response Project is to carefully consider multiple alternative models and parameters
- Widen epistemic uncertainty if warranted for
- Site response methods
- Site Vs profiles
- Treatment of nonlinear response of soil and rock
- Important site parameters such as site kappa
- Final Site Adjustment Factors
Example Site Response Logic Tree
Site Adjustment Factors
Development of Control Point Hazard Curves and GMRS
- Combine reference rock hazard curves with site response results to develop control point hazard curves
- Use Approach 3 PSHA to convolve rock hazard curves with site adjustment factors
- Develop mean Uniform Hazard Response Spectra and then GMRS
- Prepare seismic hazard update and publish in ADAMS
- Description of site geology, site response analysis, and PSHA
- Tables of rock hazard curves, site adjustment factors, control point hazard, and GMRS
Screening Evaluation
Screening Evaluation
- Changes in hazard with respect to previous GMRS
- Other factors such as plant SSE and overall hazard level between 1 and 10 Hz
- Delta risk with respect to previous plant risk assessments
- Further risk considerations
GMRS Comparisons
Further Considerations in Screening Review
- Licensing basis for approved risk-informed applications
- Insights from SPRAs submitted in response to NRCs post-Fukushima efforts
- Principles of risk-informed decision making (embodies Be riskSMART framework)
- 10 CFR 50.109 and Management Directive 8.4 (Backfitting), as applicable
References NRC, 2005, Screening Analysis for GI-199, Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants, ADAMS Accession No. ML073400504.
NRC, 2012. Central and Eastern United States Seismic Source Characterization for Nuclear Facilities, NUREG-2115, ADAMS Accession No. ML12048A776.
NRC, 2018. An Approach for Using Probabilistic Risk Assessment in Rik-Informed Decisions on Plant-Specific Changes of the Licensing Basis, Regulatory Guide (RG) 1.174, ML17317A256.
NRC, 2019. Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests, Management Directive (MD) 8.4, ADAMS Accession No. ML18093B087.
NRC, 2019. Process for the Ongoing Assessment of Natural Hazard Information, NRR LIC-208, ADAMS Accession No. ML19210C288.
NRC, 2021. Be riskSMART, Guidance for Integrating Risk Insights into NRC Decisions, NUREG/KM-0016, ADAMS Accession No. ML21071A238 NRC, 2021. Documentation Report for SSHAC Level 2: Site Response, RIL 2021-15, ADAMS Accession No. ML21323A056 NRC, 2021. Seismic Hazard Evaluations for U.S. Nuclear Power Plants: Near-Term Task Force Recommendation 2.1 Results, NUREG/KM-0017, ADAMS Accession No. ML21344A126.
Pacific Earthquake Engineering Research Center, 2018. PEER Report No. 2018/08 Central and Eastern North America Ground-Motion Characterization - NGA-East Final Report.
EPRI, 2012. EPRI Report 1025287 Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic November 27, 2012, ADAMS Accesion No.
EPRI, 2013. EPRI Ground Motion Model Review Final Report, June 3, 2013, ADAMS Accession No. ML13155A553.
Project Schedule Task Initial Milestone Revised Milestone NRC development and verification of seismic analyses computer code Q1FY22 Completed 3/31/22 Run NRC computer codes for operating plants in CEUS Screen Prioritize hazard updates using NUREG/KM-0017 results Q2FY22 Ongoing (8/50 sites completed 3 more running)
Q4FY22 Public Meeting - stakeholder interaction Q2FY22 5/17/22 Run advanced site response analyses for screened all sites Screen updated site seismic hazard GMRS relative to previous results Develop seismic hazard update report for each site Q3FY22 Ongoing Q1FY23 Public Meeting - stakeholder interaction Q3FY22 Q4FY22 Assessment of screened sites for risk significance Q4FY22 Q1FY23 Public Meeting - stakeholder interaction Q4FY22 Q1FY23
Sharing comments and information
- Staff will create a resource email to accept comments and information
- Staff will consider public comments and new information submitted through this email
- POANHI annual report will summarize comments received on POANHI projects
Questions