ICONE-22 July 7, 2014 Prague, Czech Republic Slide 1 SPEAKERS Dr. - PowerPoint PPT Presentation

Forthcoming Seismic PRA for US Operating Plants Following Fukushima Event ICONE-22 July 7, 2014 Prague, Czech Republic Slide 1

SPEAKERS § Dr. Sanj Malushte smalusht@bechtel.com § Dr. Annie Kammerer amkammer@bechtel.com § Dr. Farhang Ostadan fostadan@bechtel.com Slide 2

Contents 1. Introduction 2. Near-Term Task Force (NTTF) Recommendations 3. Recommendation 2.1: Seismic (R2.1) 4. Additional R2.1-Related Activities 5. Ground Motion Response Spectrum (GMRS) Development 6. Validation of Existing Structural/SSI Models 10 Minute Break (10:50 - 11:00) Slide 3

Contents 7. Seismic Fragility Evaluations 8. Advanced Structural Analysis Approaches 9. Plant Response Models 10. Seismic Risk Calculations and Deaggregation 11. Time Line and Current Status 12. Questions (12:10 - 12:30) Slide 4

Fukushima Near Term Task Force (NTTF) Recommendations Near-Term Task Force (NTTF) Recommendations Slide 5

NTTF Recommendations § In July 2011, NRC ’ s Near Term Task Force (NTTF) provided a report (http://pbadupws.nrc.gov/docs/ML1118/ML111861807.pdf) containing 12 overarching recommendations addressing principles of defense-in- depth, protection, mitigation and emergency preparedness (encl./SECY 11-0093) § SECY 11-0124 (http://pbadupws.nrc.gov/docs/ML1124/ML11245A127.pdf) contains NRC ’ s assessment of the NTTF recommendations that can and, in NRC ’ s judgment, should be initiated, in part or in whole, without delay § SECY 11-0137 (http://pbadupws.nrc.gov/docs/ML1126/ML11269A204.pdf) contains NRC ’ s prioritization of the NTTF recommendations, including: recommended regulatory actions, implementation challenges, technical and regulatory bases, additional recommendations, schedule and milestones

Focus Areas of NTTF Recommendations § Regulatory framework (1 recommendation) § Defense-in-depth philosophy (total 10 recommendations) § Protection from natural phenomena (2 recommendations) § Mitigation for long-term station blackout (5 recommendations) § Emergency preparedness (3 recommendations) § NRC programs (1 recommendation) § Many of the 12 NTTF recommendations were further divided into more detailed actions. In all, a total of 35 actions were identified

Broad Description of NTTF Recommendations § Recommendation 1: Enhance NRC framework for regulating beyond design basis (BDB) events and severe accidents § Recommendation 2: Update seismic and flooding analysis to protect plants from BDB events * § Recommendation 3 (Long Term Evaluation Topic): Evaluate potential enhancements to prevent or mitigate seismically induced fires and internal floods § Recommendation 4: Strengthen coping mechanisms for prolonged station blackout (SBO) events § Recommendation 5: Require reliable hardened vent designs in BWRs with Mark I and Mark II containments * Items marked in red are the focus of this presentation

Broad Description of NTTF Recommendations § Recommendation 6: Identify insights about hydrogen control and mitigation inside containment or in other buildings § Recommendation 7: Enhance spent fuel pool instrumentation and makeup capability § Recommendation 8: Strengthen and integrate onsite emergency response capabilities (EOPs, SAMGs, and EDMGs) § Recommendation 9: Require that facility emergency plans (EP) address prolonged SBO and multi-unit events

Broad Description of NTTF Recommendations § Recommendation 10: Additional EP topics related to multi-unit events and prolonged SBO (Protective equipment for emergency responders, decisionmaker qualifications, command and control, and Emergency Response Data System (ERDs)) § Recommendation 11: Additional emergency preparedness issues (offsite emergency response, EP decisionmaking, radiation monitoring, public education on radiation safety and use of potassium iodide) § Recommendation 12: Strengthen regulatory oversight of licensee safety performance (ROP) by focusing more attention on defense-in-depth requirements

Prioritization of NTTF Recommendations § SECY 11-0137 provided detailed prioritization order for all NTTF actions by organizing them into three tiers § Tier 1: Recommendations are those which the staff determined should be started without unnecessary delay and for which sufficient resource flexibility, including availability of critical skill sets, exists § Tier 1 includes eight actions, the seven identified in SECY 11-0124 plus one additional item (7.1 SFP Instrumentation) § Tier 1 actions are: 2.1, 2.3, 4.1, 4.2, 5.1, 7.1, 8, and 9.3

Prioritization of NTTF Recommendations § Tier 2: The second tier consists of those recommendations which could not be initiated in the near term due to factors that include the need for further technical assessment and alignment, dependence on Tier 1 issues, or availability of critical skill sets § Tier 2 recommendations do not require long-term study and can be initiated when sufficient technical information and applicable resources become available § Tier 2 Actions are: 7.2, 7.3, 7.4, 7.5, 9.3

Prioritization of NTTF Recommendations § Tier 3: Recommendations that require further NRC study to support a regulatory action, have an associated shorter-term action that needs to be completed to inform the longer-term action, are dependent on the availability of critical skill sets, or are dependent on the resolution of Recommendation 1 § Once the staff has completed its evaluation of the resource impacts of the Tier 1 and Tier 2 recommendations, it will be able to more accurately address the Tier 3 recommendations § Tier 3 Actions: 2.2, 3, 5.2, 6, 9.1, 9.2, 10, 11, 12.1, 12.2

Fukushima Near Term Task Force (NTTF) Recommendations Recommendation 2.1 NRC 50.54f Request for Information letter u Screening u Individual Plant Examination for External Events (IPEEE) u Phase 2 Risk-Informed Upgrade Decisions u EPRI and Industry Response u Slide 14

NTTF Recommendations NTTF Recommendations Slide 15

R2.1: Seismic Hazard and Risk Reevaluation NRC 50.54(f) Request for Information Letter § In August 2010, the NRC issued a report on Generic Issue 199 (GI-199), which demonstrated that the ground motions calculated using current techniques exceeded the ground motions used in design for a significant number of US plants (the report also noted that plants are designed with significant seismic margin) [ Fukushima accident occurs ] § On August 23, 2011, the North Anna Power Station was shut down by beyond-design-basis ground motions from the Mineral VA earthquake § On December 23, 2011, the Consolidated Appropriations Act, Public Law 112-074, was Signed into law. Section 402 of the law also requires a reevaluation of licensees' design basis for external hazards, and expands the scope to include other external events. Slide 16

R2.1: Seismic Hazard and Risk Reevaluation NRC 50.54(f) Request for Information Letter § Issued March 12, 2012 § Addressed recommendations 2.1:seismic in Enclosure 1: seismic hazard and risk reevaluation § Requested specific deliverables and process u Hazard evaluation information u Risk evaluation information (if necessary) u Spent fuel pool analysis Slide 17

R2.1: Seismic Hazard and Risk Reevaluation Seismic Guidance Development EPRI 1025286 NRC Seismic Margin EPRI 1025287 Seismic Walkdown Assessment Guidance Screening, Prioritization Guidance JLC-ISG-2012-04 and Implementation (SPID) Slide 18

R2.1: Seismic Hazard and Risk Reevaluation NRC 50.54(f) Request for Information Letter § Phase 1 includes hazard and risk reevaluation § Hazard evaluation information u Hazard curves, ground motion response spectra (GMRS), SSE used in design, and comparison of the GMRS and SSE u GMRS is a probabilistically-based, risk-targeted ground motion used in current plant design (see Regulatory Guide 1.208 and ASCE 43-05). Basis of the site-specific SSE. u Any additional insights (such as from walkdowns) gained, actions planned or taken, selected risk evaluation method (SMA or SPRA), as necessary Slide 19

R2.1: Seismic Hazard and Risk Reevaluation NRC 50.54(f) Request for Information Letter § Any additional insights (such as from walkdowns) gained, actions planned or taken, selected risk evaluation method (SMA or SPRA), as necessary Expedited Seismic Evaluation Process • Short term actions to demonstrate ability of plants to address seismic hazard while longer-term actions are ongoing • EPRI 1025286 Report provides guidance Slide 20

R2.1: Seismic Hazard and Risk Reevaluation Screening Approach EPRI SPID 1025287 Figure 1.1 Slide 21

R2.1: Seismic Hazard and Risk Reevaluation Screening Approach Seismic hazard analysis performed, GMRS developed and compared with SSE High frequency Only low frequency exceedance exceedance in low Exceedance in hazard area 1 to 10 Hz range (with or without 1 to 10 Hz exceedance) --------------- ---------------- No exceedance ------------------ Analyze low- SPRA with some frequency sensitive exceptions Addressed through components EPRI testing program Exceptions include: GMRS<1.3 x SSE at all points (SMA allowed) Very narrow band frequency exceedance Spectrum from demonstrated IPEEE HCLPF >GMRS and adequate quality demonstrated Slide 22

Screening exceptions Only low frequency Only high frequency exceedance exceedance From EPRI 1025287 ( SPID) Slide 23

Screening exceptions Narrow band exceedance 1-10Hz From EPRI 1025287 ( SPID) Slide 24