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Seismic Evaluations and Walkdowns

This timeline outlines the milestones and actions related to seismic evaluations and walkdowns, along with recommendations and potential alternative courses of action. It also highlights the need for new GMRS development and the importance of meeting NRC guidelines.

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Seismic Evaluations and Walkdowns

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  1. Seismic Evaluations and Walkdowns April 6, 2012

  2. Recommendation 2.1 (Seismic)50.54(f) Letter Timeline (CEUS) • June 10 (90-day response): Licensees propose alternate approach if cannot meet requested dates in 50.54(f) letter • Nov 2012: NRC issue guidance • Jan 2013: Licensees commit to use endorsed guidance • Sept 2013: Licensees submit GMRS • Oct 2016: High priority plants compete risk evaluations • Oct 2017: Lower priority plants complete risk evaluations

  3. Recommendation 2.1 (Seismic)50.54(f) Letter Timeline (WUS) • June 10 (90-day response): Licensees propose alternate approach if cannot meet requested dates in 50.54(f) letter • Nov 2012: NRC issue guidance • Jan 2013: Licensees commit to use endorsed guidance • March 2015: Licensees submit GMRS • April 2018: High priority plants compete risk evaluations • April 2019: Lower priority plants complete risk evaluations

  4. Recommendation 2.3 (Seismic)50.54(f) Letter Timeline • May 31: NRC issue guidance • June 10 (90-day response): Licensees propose alternate approach if cannot meet requested dates in 50.54(f) letter • July 10: Licensees commit to use NRC procedure • Nov. 27: Licensee submit final response

  5. Strategy for 90-Day Response • 2.1 Evaluations • Commit to submit GMRS on schedule • 18 months for CEUS plants • 3 years for western plants • Cannot commit to schedule until SMA/SPRA guidance is finalized • Will commit to schedule 60 days after guidance is issued • If necessary, will recommend alternative course of action • 2.3 Walkdowns • Need for alternative scope/schedule will depend on whether NRC endorses our recommended guidance

  6. Recommendation 2.1 (Seismic)Primary Course of Action • Develop new GMRS • Based on GMRS-to-SSE comparison (GMRS-to-HCLPF for full-scope IPEEE SMA plants): • No additional work • Fault-space based “NRC” SMA, or • Significant resource load for NRC SMA - Most utilities would probably opt for SPRA • Seismic PRA • Technical resource issue - Need simplifications to meet NRC’s timeline • Structural analysis of spent fuel pool (not SPRA)

  7. Screening, Prioritization, and Implementation Details for Primary Course of Action to Meet Requested Timeline • Examples: • Use existing site characterization data • Compare GMRS to IPEEE HCLPF for screening • Use existing structural models • Allow reasonable treatment of high frequency • Evaluate failure modes associated with the reinforced concrete spent fuel pool enclosure (not failures of connected systems or seismically-induced flooding). • Requesting NRC agreement by May 25, 2012

  8. Need for an Alternative • Will NRC agree with screening, prioritization, and implementation details? • Develop potential Alternative Course of Action in parallel with pursuing screening, prioritization, and implementation details for the Primary Course of Action • Alternative would focus on Fukushima lessons learned first, then broader GI-199 type evaluation • Decide whether to pursue alternative based on risks/benefits of alternative and NRC’s approach

  9. Potential Alternative Course of Action • Part 1 – Functional SMA (by 2016) • Develop new GMRS • Perform success path type SMA to ensure that installed equipment needed for Phase 1 of FLEX can accommodate the GMRS • Part 2 – Seismic PRA (extending beyond 2016) • Develop implementation guidance • Perform SPRA pilot(s) • Resolve high frequency issue • Update SPRA guidance based on pilot(s) and latest data • Industry-wide implementation of SPRAs

  10. Near-term Actions • March 26: Send NRC 2.3 walkdown guide outline and 2.1 screening, prioritization, and implementation details • March 29: EPRI webcast for utilities • April 2-3: NRC meeting in Palo Alto • April 5-6: NEI workshop • April 30: Submit walkdown guidance to NRC • May 4: Submit 2.1 guidance to NRC • May 15: NRC meeting in Palo Alto • May 18: Steering Committee meeting at NEI • ~June 10: 90-day response

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