ML15159B297

Near-Term Task Force Recommendation 2.1 (R2.1) Seismic Hazard Evaluation - Arizona Public Service, Palo Verde Nuclear Generating Station Public Meeting - June 9, 2015

ML15159B297
Person / Time
Site:	Palo Verde
Issue date:	06/09/2015
From:	Japan Lessons-Learned Division
To:
Vega F, NRR/JLD, 415-1617
References
Download: ML15159B297 (16)

Text

Near-term Task Force Recommendation 2.1 (R2.1)

Seismic Hazard Evaluation Arizona Public Service Palo Verde Nuclear Generating Station Public Meeting June 9, 2015

References and Logistics

• NRC Presentation Slides - ML15159B297

• NRC Technical Focus Area Questions -ML15147A068

• Licensee Presentation Slides - ML15156B331

• Licensee Hazard Report and Supplement -

ML15076A073; ML15105A076

• Screening and prioritization results -

ML15113B344

• Meeting Feedback Form (request from fgv1@nrc.gov or njd2@nrc.gov)

• Meeting Summary to be issued within 30-day 2

Meeting Purposes

• Gather additional information based on early identification of areas where additional technical information will support the staffs review

• Gain a better understanding of how the licensee conducted their evaluation 3

Outline

• Overview of Recommendation 2.1 -

Response to NRC 50.54(f) letter

• Screening and Prioritization results

• NRC approach to seismic hazard characterization reviews for Western US (WUS) sites

• Review schedules and timeline 4

Seismic R2.1 Process Ensures Clarity, Consistency, and Risk-Informed Regulatory Decisions PHASE 1 INFORMATION GATHERING STAGE 1 STAGE 2 PHASE 2 Screen and prioritize plants DECISION-MAKING Interact with Industry on for Risk Evaluation.

Hazard and Risk Review Interim Evaluations, Evaluation Guidance as needed NRC makes Regulatory (CEUS:5/2014; WUS:5/2015)

Decisions as Needed CEUS Licensees submit Screened-in plants Site Response (9/2013 &

• Safety Enhancements complete Expedited Interim 3/2014)

• Backfit Analysis Evaluation (CEUS:12/31/2014;WUS:1/2016)

• Modify Plant License and Risk Evaluation Licensees submit Hazard (Group 1: 6/2017)

Reevaluations and Interim Evaluations, as needed (CEUS:3/2014,WUS:3/2015) NRC reviews Risk Evaluation 5

Seismic Screening and Prioritization results

• NRC Letter issued for WUS sites on May 13, 2015 (ML15113B344)

• Palo Verde has been conditionally screened-in for seismic risk evaluation and limited scope evaluations

- Review Group 3 plant

• No immediate safety issues identified

• Information supports safety assurance allowing additional time to complete the seismic risk evaluation 6

NRC Review of SSHAC Studies for WUS Sites

• Did SSHAC process follow NRC guidance?

• How effective was the peer review panel?

• Have all applicable data been considered?

• Were data uncertainties identified and considered?

• Was an appropriate range of applicable models considered?

• How were models selected and weighted in the analysis?

• How were models assembled into the PSHA?

7

NRC Review of Source Models for WUS Sites

• How were seismic sources identified?

- Geologic mapping

- Geophysical observations

- Earthquake catalog

• How were seismic sources characterized?

- Geometry (location, length, dip)

- Range of magnitudes

- Faulting style (normal, reverse, strike-slip)

- Slip rate and recurrence models

- Complex rupture scenarios 8

NRC Review of Ground Motion Models and Site Response for WUS Sites

• Do final ground motion models capture a reasonable range of alternative models?

• How were sources of uncertainty captured in model development?

• How were ground motion models adjusted for local site geology?

• Does site response analysis cover a reasonable range of alternative soil/rock properties?

• How was uncertainty in site response analysis incorporated into final probabilistic hazard curves?

9

WUS Hazard Staff Review Timeline

• March 2015: WUS Hazard Submittals

• May: Screening and prioritization letter

• June: Public meetings

• Late summer/early fall: Staff questions

• Fall: NRC final screening letter including ESEP response

• December: GMRS suitability Letter

• Summer/Fall 2016: Document Hazard review

• December 2020: Risk Evaluation submittal (Grp 3) 10

Break for NRC Staff Alignment

• 5 - 10 minute planned break for NRC staff alignment to support meeting wrap-up 11

Opportunity for Public Questions or Comments

• Additional Questions?

Please ask us at:

JLD_Public.Resource@nrc.gov 12

List of Acronyms

• CEUS - Central and Eastern United States

• ESEP - Expedited Seismic Evaluation Process (for Interim Evaluation)

• GMRS - Ground Motion Response Spectrum

• NRC - U.S. Nuclear Regulatory Commission

• NPP - Nuclear Power Plant

• NTTF - Near-Term Task Force

• PSHA - Probabilistic Seismic Hazard Analysis

• SFP - Spent Fuel Pool

• SMA - Seismic Margins Analysis

• SPID - Screening, Prioritization, and Implementation Details SPID

• SPRA - Seismic Probabilistic Risk Assessment

• SSC - Structures, Systems and Components

• SSHAC - Senior Seismic Hazard Analysis Committee

• SSE - Safe Shutdown Earthquake

• SPID - Screening, Prioritization, and Implementation Details

• WUS - Western United States 13

Backup Slides 14

Guidance Documents

• Two main guidance documents proposed by industry and endorsed by the NRC

• Screening, Prioritization, and Implementation Details (SPID)

- Submitted by EPRI on November 2012

- Endorsed by NRC on February 15, 2013

- EPRI-1025287 (ML12333A170)

• Seismic Evaluation Guidance: Augmented Approach (aka Expedited Approach)

- Submitted by EPRI on April 9, 2013

- Endorsed by NRC on May 7, 2013

- EPRI-3002000704 (ML13102A142) 15

Schedule for Seismic Hazard and Risk Evaluations 2012 2013 2014 2015 2016 2017 2018 2019 2020 CEUS Hazard All plants Development WUS plant mods Expedited CEUS Interim plant mods Only plants WUS with new Evaluations seismic hazard exceeding Risk Evaluations design basis Group 1 Higher Priority Group 2 Group 3 (as needed)

Lower Priority Hazard Analyses Risk Evaluations Staff Assessment or Expedited Interim Staff acknowledgement to response Evaluations use GMRS for risk evaluation 16