ML14160B128
| ML14160B128 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/05/2014 |
| From: | Stoddard D Dominion, Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 14-258 | |
| Download: ML14160B128 (5) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 June 5, 2014 U.S. Nuclear Regulatory Commission Serial No.14-258 Attention: Document Control Desk NL&OS/WDC RO Washington, DC 20555 Docket Nos. 50-280/281 License Nos. DPR-32/37 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
SURRY POWER STATION UNITS I AND 2 RESPONSE TO MARCH 12, 2012 INFORMATION REQUEST DESCRIPTION OF INTERIM EVALUATION RESULTS RELATED TO SEISMIC HAZARD AND SCREENING REPORT (CEUS SITES) FOR RECOMMENDATION 2.1
References:
- 1. NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012
- 2. Virginia Electric and Power Company Letter, "Response to March 12, 2012 Information Request Seismic Hazard and Screening Report (CEUS Sites) for Recommendation 2.1," dated March 31, 2014
- 3. NRC Letter, "Screening and Prioritization Results Regarding Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Re-Evaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated May 9, 2014
- 4. NRC Letter, "Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(F) Regarding Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated February 20, 2014
- 5. NEI Letter, "Seismic Risk Evaluations for Plants in the Central and Eastern United States," dated March 12, 2014
- 6. NRC Information Notice 2010-18, 'Generic Issue (GI) 199, "Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants,"' and NRC Memorandum from Patrick Hiland to Brian Sheron, "Safety/Risk Assessment Results for GI-199," September 2, 2010
Serial No.14-258 Docket Nos. 50-280/281 Page 2 of 5
- 7. Virginia Electric and Power Company Letter, "Surry Power Station, Units 1 and 2, Summary Report for Individual Plant Examination of External Events (IPEEE) -
Seismic," dated November 26, 1997
- 8. Virginia Electric and Power Company Letter, "Surry Power Station Units 1 and 2, Report in Response to March 12, 2012 Information Request Regarding Seismic Aspects of Recommendation 2.3," dated November 27, 2012
- 9. NRC Letter, "Surry Power Station, Unit 1 - Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima Dai-ichi Nuclear Power Plant Accident (TAC No. MF01 81)," dated April 9, 2014 10.NRC Letter, "Surry Power Station, Unit 2 - Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima Dai-ichi Nuclear Power Plant Accident (TAC No. MF01 82)," dated April 9, 2014 On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1 of Reference 1 requested each addressee in the Central and Eastern United States (CEUS) to submit a Seismic Hazard and Screening Report.
Reference 2 provided the Seismic Hazard and Screening Report for Surry Power Station (Surry) Units 1 and 2. In Reference 3, NRC requested plants identified as "conditional screen-in" to complete interim evaluations, identify any associated actions, and submit the results to the NRC no later than June 6, 2014. Although Surry "screened-out" based on the results provided in Reference 2, this letter provides the requested interim evaluation information because the NRC determined Surry to be "conditionally screened-in" in Reference 3.
Consistent with NRC letter dated February 20, 2014 (Reference 4), the seismic hazard reevaluations to be completed as part of the response to Reference 1 are distinct from the current design and licensing bases for Surry Units 1 and 2. Therefore, the results do not call into question the operability or functionality of plant structures, systems and components (SSCs) and are not reportable pursuant to 10 CFR 50.72, "Immediate notification requirements for operating nuclear power reactors," and 10 CFR 50.73, "Licensee event report system."
NEI letter dated March 12, 2014 (Reference 5) provides seismic core damage risk estimates using the same approach as used in Reference 6 with the updated seismic hazards for the operating nuclear plants in the Central and Eastern United States, including Surry. Dominion's estimates of the seismic core damage frequency (CDF) are consistent with the conclusions in Reference 5, i.e., the weighted (average of four frequencies) seismic CDF using the methods in Reference 6 for Surry is less than
Serial No.14-258 Docket Nos. 50-280/281 Page 3 of 5 1E-4 per year. These risk estimates continue to support the following conclusions of the NRC GI-1 99 Safety/Risk Assessment:
Overall seismic core damage risk estimates are consistent with the Commission's Safety Goal Policy Statement because they are within the subsidiary objective of 10 4 /year for core damage frequency. The GI-199 Safety/Risk Assessment, based in part on information from the U.S. Nuclear Regulatory Commission's (NRC's) Individual Plant Examination of External Events (IPEEE) program, indicates that no concern exists regarding adequate protection and that the current seismic design of operating reactors provides a safety margin to withstand potential earthquakes exceeding the original design basis.
A seismic probabilistic risk assessment (PRA) was performed for Surry to identify potential seismic vulnerabilities in response to NRC Generic Letter 88-20, Supplements 4 and 5. The results were submitted to the NRC in the IPEEE Summary Report (Reference 7). The seismic PRA quantification concluded that no severe accident vulnerabilities exist at Surry from a seismic event. The IPEEE program was run concurrently with the Unresolved Safety Issue (USI) A-46 program for Surry and resulted in comprehensive walkdowns of safe-shutdown equipment, detailed relay evaluations, and analyses of tanks, cable trays and conduit systems. As a result of these evaluations, several plant safety enhancements were made, as identified in the IPEEE Summary Report (Reference 7).
In addition, Surry recently performed walkdowns in response to NTTF Recommendation 2.3: Seismic and submitted the results to the NRC in a seismic walkdown summary report (Reference 8). There were no significant findings regarding Surry's ability to meet its seismic design basis. The IPEEE commitments were also confirmed to be met, as stated in the walkdown report. The NRC has reviewed the Seismic Walkdown Summary Report, and the results of the staff assessment conclude that sufficient information was provided to be responsive to the requirements of the 10 CFR 50.54(f) letter as documented in References 9 and 10.
As noted in Reference 3, the NRC staff considered a plant to be "conditionally screened-in" when the "staffs independent GMRS assessment could differ from the GMRS provided in the March 2014 submittals, and these differences need to be better understood before determining if a plant would screen out from further evaluation.
.... interactions with the licensees are needed to reach resolution." Such is the case with Surry. Accordingly, Dominion requests a meeting with the NRC staff to resolve differences between the NRC staff seismic assessment for Surry and the results provided in the Reference 2 submittal.
Based on the interim evaluations described above and pending resolution of GMRS differences, Dominion concludes that the current Surry seismic design continues to provide safety margins to withstand its design basis earthquake, as well as the GMRS
Serial No.14-258 Docket Nos. 50-280/281 Page 4 of 5 that was recently developed using probabilistic seismic hazard analysis and submitted in Reference 2.
If you have any questions regarding this information, please contact Mr. Gary D. Miller at (804) 273-2771.
Sincerely, Daniel G. Stoddard Senior Vice President - Nuclear Operations Virginia Electric and Power Company Commitments made in this letter: No new regulatory commitments COMMONWEALTH OF VIRGINIA )
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COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Daniel G. Stoddard, who is Senior Vice President - Nuclear Operations of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this 5"4 day of "3 ,-r- , 2014.
My Commission Expires: -31, -Z0 k WANDA6D.;RAF Notary Public v-.nonwealth of Virginia jNotar -DPuli Notary Public "
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Serial No.14-258 Docket Nos. 50-280/281 Page 5 of 5 cc: U.S. Nuclear Regulatory Commission, Region II Regional Administrator Marquis One Tower 245 Peachtree Center Ave. NE Suite 1200 Atlanta, Georgia 30303-1257 Dr. V. Sreenivas Project Manager - North Anna and Surry U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 G-9A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Surry Power Station 50.54fSeismic. Resource@nrc.gov