ML12363A090
| ML12363A090 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/18/2011 |
| From: | Grobe J Office of Nuclear Reactor Regulation |
| To: | Gillespie P Duke Energy Carolinas |
| References | |
| TAC ME6133, TAC ME6134, TAC ME6135, FOIA/PA-2012-0128 | |
| Download: ML12363A090 (3) | |
Text
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ý,ý August 18, 2011 Mr. Preston Gillespie Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672
SUBJECT:
OCONEE NUCLEAR STATION, UNITS 1,2, AND 3, ASSESSMENT OF DUKE ENERGY CAROLINAS, LLC'S, APRIL 29, 2011, RESPONSE TO CONFIRMATORY ACTION LETTER REGARDING MODIFICATIONS TO ADDRESS EXTERNAL FLOODING CONCERNS (TAC NOS. ME6133, ME6134, AND ME6135)
Dear Mr. Gillespie:
By letter dated June 22, 2010, the U.S. Nuclear Regulatory Commission (NRC) issued a confirmatory action letter (CAL) to Duke Energy Carolinas, LLC (Duke, the licensee), associated with the mitigation of external flooding hazards at the Oconee Nuclear Station, Units 1, 2, and 3 (ONS) site, resulting from a postulated failure of the Jocassee Dam. The CAL confirmed your commitment to submit to the NRC by November 30, 2011, a list of all necessary modifications to enhance the capability of the ONS site to withstand the postulated failure of the Jocassee Dam.
In your letter dated November 29, 2010, you stated that you would provide the list of modifications to the NRC by April 30, 2011.
By letter dated April 29, 2011, you provided the required information to the NRC. The NRC reviewed the information provided, and found that additional information is necessary for the NRC to determine if the commitments in the CAL were met. Please provide the following information associated with your modifications and associated mitigation strategies:
Justification for the statement in your April 29, 2011, letter that the postulated failure of the Jocassee Dam is considered a beyond design basis event.
Clarification that natural phenomena are not design basis events at ONS (i.e., high winds, external flooding, and seismic events).
" Justification for the assumptions used in the development of the mitigating strategies and the entry conditions associated with each phase of the mitigation strategies.
A summary of the sequence of actions for achieving each phase of the mitigating strategies. Identify when each operator action has to be completed. In addition, demonstrate that the sequence of events would not result in unacceptable radiological consequences. Identify and justify the selected acceptance criteria, and provide a detailed description of the analyses performed to support the conclusion.
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" Justification for not installing the modifications, to enhance the capability of the ONS site to mitigate the postulated failure of the Jocassee Dam, in accordance with the Title 10 of the Code of Federal Regulations, Appendix B, quality assurance criteria.
0 A description of the standards used in the development of the calculations and the new procedures to support your mitigating strategies.
A schedule for the modifications with identification of key elements. include justification for time required to implement the modifications.
Based on the above, this CAL remains open. Provide a response to the above items within 45 days from the date of this letter.
If you have any questions, please call John Stang at 301-415-1345.
Sincerely, IRA/
John A. Grobe Deputy Director for Engineering and Corporate Support Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287 U
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