ML12005A089
| ML12005A089 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/15/2011 |
| From: | Quattlebaum B SCANA Corp |
| To: | Carol Gallagher Division of Administrative Services |
| References | |
| 76FR54507 00025 | |
| Download: ML12005A089 (2) | |
Text
Docket ID: NRC-2011-0204 Draft Generic Letter on Seismic Risk Evaluations for Operating Reactors Page 1 of 2 Re Reply
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1: 0Help From:
sarabeth.quattlebaum@scana.com Sent:
Thursday, December 15, 2011 3:26:17 PM To:
Carol.Gallagher@nrc.gov L-h)
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BTHOMPSON@scana.com ERUMFELT@scafia.6mo-r, GLOIGNON@scana.com, DKRAUSE@scana.com, RWHORTON@scana.com, RFOWLKES@scana.com, SZARANDl@scana.com
Subject:
Docket ID: NRC-2011-0204 : Draft Generic Letter on Seismic Risk Evaluations for Operating Reactors R Digital Signature is VALID SCE&G's V.C. Summer Nuclear Station Unit I appreciates the opportunity to provide comments on the draft generic letter on seismic risk evaluations for operating reactors. Comments are provided below.
The U.S. Nuclear Regulatory Commission has issued a draft generic letter (GL) in an effort to resolve Generic Issue 199, "Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern U.S. for Existing Plants." The draft letter (which solicits comments) requests that addressees evaluate their facilities to determine the current level of seismic risk and requests additional information to facilitate resolution of the issue. Prior to the issuance of the draft generic letter, NEI created a seismic task force to assist in relaying industry comments. This task force drafted a comment letter which included an improved timeline for plant implementation, a concept of pilot plants to develop the process and necessary guidance for conducting new seismic analyses, identified several areas in which guidance criteria needed to be established, and expressed concerns over the amount of resources needed for licensees to perform the Work.
SCE&G supports the NEI task force and agrees with the comments provided by NEI for the industry. The development of an integrated, performance-based approach to optimize the implementation of lessons learned from the Fukushima Daiichi accidents will help identify diverse and flexible capabilities and strategies that could be implemented in the near term to mitigate the effects of extreme natural events. In the long term, it will be important to have an established process for evaluating the effects of new seismic hazard information and methodologies to determine whether additional safety enhancements are appropriate.
The process described in the GI-199 draft generic letter is one possible approach for such evaluations. SCE&G further agrees with NEI that there is an insufficient timeframe to address the requested amount of work. In addition there are inconsistencies in the order of activities requested be completed and concerns over establishing a consistent criteria for performing system walkdowns, and generating a Ground Motion Response Spectrum (GMRS) for comparison with SSE.
Based on the timeline and phases of completion listed in the draft generic letter, V.C. Summer (VCS) has three plant specific responses;
- 1)
Phase 1 (90 days) - VCS will need to provide a summary of the IPEEE results, including plant enhancements, vulnerabilities, etc. This response should include updated High Confidence Low Probability of Failure (HCLPF) assessments. It will also contain a review of our historical data from 20 years ago. A timeframe of 180 days is more realistic for a task of this nature.
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Docket ID: NRC-2011-0204 : Draft Generic Letter on Seismic Risk Evaluations for Operating Reactors Page 2 of 2
- 2)
Phase 2 (180 days) - Using the forthcoming CEUS seismic source characterization model, develop site-specific seismic hazard curves and GMRS with a comparison to the SSE. The timeframe of 180 days for completion of Phase 2 is not sufficient to address the scope of these activities. This timeframe is based on the issuance of EPRI plans and CEUS seismic source characterization which are still uncertain.
- 3)
Phase 3 (1 year) - Re-evaluation of the IPEEE Seismic Margins Analysis (SMA). The scope of this effort cannot be effectively defined until the completion of Phase 2. Additional resources, contractor support and vendor training will be necessary to support this effort. Availability of these resources makes the proposed timeframe too short. SCE&G estimates the Phase 3 efforts will require upward of two to two and a half years to complete.
Thank you and Happy Holidays, Nuclear Licensing Engineer 803-345-4723 V.C. Sumniner Nuclear Station Unit 1
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