overview of nrc’s probabilistic flood hazard assessment
TRANSCRIPT
![Page 1: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/1.jpg)
1
Overview of NRC’s Probabilistic Flood Hazard Assessment
Research Program
5th Annual PFHA Research WorkshopNRC HQ, Rockville, MDFebruary 19 – 21, 2020
Thomas Aird*, Meredith Carr, Mark Fuhrmann, Joseph Kanney, Elena Yegorova
Fire and External Hazards Analysis BranchDivision of Risk Analysis
Office of Nuclear Regulatory Research
![Page 2: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/2.jpg)
Outline
• Objectives• Key Challenges• Research Approach• Selected Projects• Future Directions
2
![Page 3: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/3.jpg)
PFHA Research Objectives
• Address significant gap in technical basis for guidance for probabilistic assessment of external hazards– Probabilistic: seismic, high winds– Deterministic: flooding
• Develop resources, tools and selected guidance– Support risk-informed licensing and oversight activities
associated with flooding hazards and consequences• Licensing and oversight in operating reactor program• Design basis flood hazard assessments for new facilities
– Readiness for licensing of advanced reactors
3
![Page 4: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/4.jpg)
Key Challenges• Hazard Curve Development
– Range of annual exceedance probabilities (AEPs)
• Moderately rare to extreme floods– Multiple flooding mechanisms
• Coincident and correlated mechanisms– Uncertainty characterization and
estimation• Aleatory (e.g. storm recurrence rates)• Epistemic (e.g. model structure,
parameters)• Fragility Curve Development
– Information on reliability of flood protection features and procedures is sparse
– Cliff-edge effects
4
Magnitude
Load Intensity
Failu
re P
roba
bilit
y
![Page 5: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/5.jpg)
Phased Approach
• Phase 1 (FY15-FY19)– Technical basis research
• Phase 2 & 3 (FY20-FY22)– Selected draft guidance documents– Perform pilot studies – Finalize guidance
5
![Page 6: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/6.jpg)
6
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 7: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/7.jpg)
7
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 8: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/8.jpg)
Leverage Available Flooding Information
• Development of Natural Hazard Information Digests for Operating NPP Sites (INL)– Completed (continue with updates/maintenance)
• Application of State-of-Practice Flood Frequency Analysis Methods and Tools (USGS)– Completed – USGS Scientific Investigation Report– https://pubs.er.usgs.gov/publication/sir20175038– 2nd USGS SIR in publication
• Extreme Precipitation Estimates in Orographic Regions (USBR)– Completed - NUREG/CR report in publication
• Technical Basis for Extending Frequency Analysis Beyond Current Consensus Limits (USBR)– In progress (completion expected in FY20)
8
![Page 9: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/9.jpg)
• Eastern US Riverine Flood Geomorphology Feasibility Study (USGS) – Completed – USGS Scientific Investigations Report
• (https://doi.org/10.3133/sir20175052)• Eastern US Riverine Flood Geomorphology
Comprehensive Study (USGS) – In progress (completion expected FY20)
• Framework for Technical Review of Paleoflood Information (USGS)– In progress (completion expected FY20)
• Workshop summary: ML19200A281• Application of Point Precipitation Estimates to
Watersheds (ORNL)–Completed (NUREG/CR report in publication)
9
Leverage Available Flooding Information
![Page 10: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/10.jpg)
10
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 11: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/11.jpg)
PFHA Modeling Frameworks• Probabilistic Flood Hazard Assessment Framework
Development (USACE)– In progress (completion expected FY20)
• Structured Hazard Assessment Committee Process for Flooding (SHAC-F) for LIP & Riverine Flooding (PNNL)– In progress (completion expected FY20)
• Development of SHAC-F for Coastal Flooding (PNNL & USACE)– In progress (completion expected FY20)
• Methods for Estimating Joint Probabilities of Coincident and Correlated Flooding Mechanisms for Nuclear Power Plant Flood Hazard Assessments (ORNL)– In progress (completion expected FY20)
• Task 1 (Literature review) completed• Task 2 (Critical Assessment of Selected Methods and
Approaches) Completed.11
![Page 12: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/12.jpg)
12
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 13: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/13.jpg)
• Numerical Modeling of Local Intense Precipitation Processes (USGS/UC Davis)– Completed - NUREG-CR report in publication – Peer-reviewed papers: Mure-Ravaud, et al. (2019a,b)
https://www.sciencedirect.com/science/article/pii/S0048969719306734– https://www.sciencedirect.com/science/article/pii/S0048969719306291
• Quantifying Uncertainties in Probabilistic Storm Surge Models (USACE)– In Progress (completion expected FY20)– Task 1 (Literature Review) Completed. ERDC/CHL SR-19-1
• https://erdc-library.erdc.dren.mil/xmlui/handle/11681/32293– Task 2 (Storm Recurrence Rate Models) Completed. ERDC/CHL TR-19-4
• https://apps.dtic.mil/docs/citations/AD1073835• Erosion Processes in Embankment Dams (USBR)
– Completed - NUREG-CR report in publication • Convection-Permitting Modeling for Intense Precipitation Processes (NCAR)
– In Progress (completion expected FY21)13
Improved Modeling
![Page 14: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/14.jpg)
14
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 15: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/15.jpg)
• Modeling Plant Response to Flooding Events (INL)– Completed. NUREG/CR report in publishing
• Effects of Environmental Factors on Manual Actions for Flood Protection and Mitigation at Nuclear Power Plants (PNNL)– Completed. NUREG/CR report in publication process
• Critical Review of the State of Practice in Probabilistic Risk Assessment for Dams (ORNL, UMD)– Completed. ORNL report available at
https://www.osti.gov/biblio/1592163-current-state-practice-dam-safety-risk-assessment
• Performance of Flood Penetration Seals at NPPs (Fire Risk Management, Inc.)- Completed. NUREG report in publication process
• Flood Barrier Testing Strategies (INL/ISU)– In Progress. Public workshop to be held March 12 - 13
15
Reliability of Flood Protection
![Page 16: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/16.jpg)
16
Phase 1 Technical Basis
Projects
Leverage Available Flood InformationPFHA Modeling
FrameworksImproved ModelingReliability of Flood
ProtectionDynamic and Nonstationary
Processes
![Page 17: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/17.jpg)
Dynamic and Nonstationary Processes
• Regional Climate Change Projections: Potential Impacts to Nuclear Facilities (PNNL) – Year 1 (CONUS) – Complete
• published as a PNNL report (PNNL-24868)– Year 2 (Southeast US) - Complete
• published as a PNNL report (PNNL-26226)– Year 3 (Midwest US) – Complete
• published as a PNNL report (PNNL-27452 Rev1)– Year 4 (Northeast US) – Complete
• published as a PNNL report (PNNL-29079)
17
![Page 18: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/18.jpg)
18
Future Directions for PFHA
Phase 1 Technical
BasisProjects
Phase 2 Pilot ProjectsApplication Inform & update
Phase 3Guidance
![Page 19: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/19.jpg)
19
Future Directions for PFHA
Phase 1 Technical
BasisProjects
Phase 2 Pilot ProjectsApplication Inform & update
Phase 3Guidance
![Page 20: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/20.jpg)
Objective: Synthesize results from technical basis research– Multiple flooding mechanism contribution to hazard curves– Quantify key aleatory variabilities and epistemic uncertainties
LIP Flooding PFHA Pilot (PNNL) – Pilot study to inform development of guidance for
probabilistic assessment of flooding hazards at NPPs due to local intense precipitation events
Riverine PFHA Pilot (USACE/HEC)
Coastal Flooding Pilot PFHA Pilot (USACE/ERDC)
20
Phase 2 Pilot Studies
![Page 21: Overview of NRC’s Probabilistic Flood Hazard Assessment](https://reader030.vdocuments.net/reader030/viewer/2022032823/6213de7897c5c16fc34cbdce/html5/thumbnails/21.jpg)
• Revise guidance documents based on pilots• Stakeholder & Public Interactions• Finalize guidance
21
Phase 3 (FY22-?)
Questions? Contact: [email protected]
Phase 1 Technical
BasisProjects
Phase 2 Pilot ProjectsApplication Inform & update
Phase 3Guidance