ONS-2017-059, Transmittal of Response to March 12, 2012 Request for Information, Recommendation 2.1 Flooding, Required Response 3, Flooding Focused Evaluation Summary

Transmittal of Response to March 12, 2012 Request for Information, Recommendation 2.1 Flooding, Required Response 3, Flooding Focused Evaluation Summary

ML17222A068
Person / Time
Site:	Oconee
Issue date:	07/31/2017
From:	Teresa Ray Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML17222A065	List: ONS-2017-059, Transmittal of Response to March 12, 2012 Request for Information, Recommendation 2.1 Flooding, Required Response 3, Flooding Focused Evaluation Summary
References
ONS-2017-059
Download: ML17222A068 (3)

Text

Enclosure Contains Security Sensitive Information. Withhold From Public Disclosure Under 10 CFR 2.390.

• • fl DUKE ThomasD Ray

~~ENERGY Vice President Oconee Nuclear Station Duke Energy ON01 VP I 7800 Rochester Hwy Seneca, SC 29672 ONS-2017-059 o: 864.873.5016

f. 864.873. 4208 Tom.Ray@duke-energy.com July 31, 2017 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 10 CFR 50.54(f)

Duke Energy Carolina, LLC (Duke Energy)

Oconee Nuclear Station (ONS), Unit 1, 2 and 3 Docket Numbers 50-269, 50-270, 50-287 Renewed License Numbers DPR-38, DPR-47, and DPR-55

Subject:

Response to March 12, 2012 Request for Information, Recommendation 2.1, Flooding, Required Response 3, Flooding Focused Evaluation Summary

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 (Accession No. ML12053A340).

2. Duke Energy Letter, Revised Flood Hazard Reevaluation Report per NRC's Request for Additional Information, dated March 6, 2015 (Accession No. ML15072A106).

3. NRC Letter, Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50. 54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 1, 2013 (Accession Number ML13044A561 ).

4. NRC Letter, Coordination of Requests for Information Regarding Flooding Hazard Reevaluations and Mitigating Strategies for Beyond-Design-Basis External Events, dated September 1, 2015 (Accession Number ML15174A257).

5. Nuclear Energy Institute (NEI) Report, NEI 16-05, Revision 1, External Flooding Assessment Guidelines, dated June 2016 (Accession Number ML16165A178)

6. NRC Letter, Oconee Nuclear Station, Units 1, 2, and 3 - Interim Staff Response to Reevaluated Flood Hazards Submitted in Response to 10 CFR 50. 54(f) Information Request Flood-Causing Mechanism Reevaluation, dated September 24, 2015 (Accession No, ML152398243).

7; NRC Letter, Oconee Nuclear Station, Units 1, 2, and 3 - Staff assessment of Response to Request for Information Pursuant to 10 CFR 50.54(f) Flood-Causing Mechanisms Reevaluation (GAG nos. MF1012, MF1013, and MF1014) and Path Forward on Confirmatory Action Letter, dated April 14, 2016 (Accession No, ML15356A158). lO Ladies and Gentlemen pb~~(\

On March 12, 2012, the NRC issued Reference 1 to request information associated with Near Term Task Force (NTTF) Recommendation 2.1 for Flooding. One of the required responses directed licensees to submit a Flood Hazard Reevaluation Report (FHRR). The final FHRR for Oconee Nuclear Station (ONS) was submitted on March 6, 2015 (Reference 2). The NRC stated Enclosure Contains Security Sensitive Information. Withhold From Public Disclosure Under 10 CFR 2.390.

(Upon removal of the enclosure, this cover letter is uncontrolled)

Enclosure Contains Security Sensitive Information. Withhold From Public Disclosure Under 10 CFR 2.390.

ONS-2017-059 July 31, 2017 Page 2 of 2 in Reference 3 that it considers the reevaluated flood hazard to be "beyond the current design/licensing basis of operating plants."

The NRC issued Reference 4 to inform the industry that new guidance regarding flood hazard responses would replace existing integrated assessment instructions and would provide "a graded approach to flooding reevaluations and would provide for more focused evaluations of local intense precipitation and available physical margin in lieu of an integrated assessment."

The NRC has endorsed NEI 16-05, Revision 1 "External Flooding Assessment Guidelines."

• (Reference 5) which directs that for each flood-causing mechanism not bounded by a Design Basis (DB) flood (using only stillwater and/or wind-wave run-up levels), evaluations should follow one of the following five assessment paths:

Path 1: Demonstrate Flood Mechanism is Bounded Through Improved Realism, Path 2: Demonstrate Effective Flood Protection, Path 3: Demonstrate a Feasible Response to LIP, Path 4: Demonstrate Effective Mitigation, Path 5: Scenario Based Approach.

The required response for non-bounded* flood-causing mechanisms assessed by Paths 1, 2, or 3 calls for performance of a Flooding Focused Evaluation. ONS had three flood causing mechanisms that were not bounded by a DB flood and used Path 2 for its Focused Evaluation assessment; The enclosure to.this letter provides the ONS Floodin~ Focused Evaluation Summary Report which followed NEI 16-05, utilizing Appendix B and C for guidance to evaluate the site protection features.

The flooding analysis documented in References 6 and 7 were utilized as input to this Flooding Focused Evaluation. The Flooding Focused Evaluation reaffirms that the ONS has reliable, passive protection of Key Structures, Systems, and Components (SSCs) to main.tain Key Safety Functions (KSFs) for the three flood causing mechanisms. ONS does not require human actions to protect Key SSCs, so an evaluation of the overall site response is not necessary.

This submittal completes the actions related to external flooding required by the Reference 1 letter.

This letter contains no new or revised Regulatory Commitments.

Should you have any questions regarding this submittal, please contact Laura Todd with Oconee Regulatory Affairs, at (864) 873-6774.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on July 31, 2017 Thomas D. Ray Vice President Oconee Nuclear Station 1=:nclosure:

!Oconee Nuclear Station Flooding Focused Evaluation Summary Report El"lclosure Contains Security Sensitive Information. Withhold From Public Disclosure Under 10 CFR 2.390.

(Upon removal of the enclosure, this cover letter is uncontrolled)

ONS-2017-059 July 31, 2017 cc:

Ms. Catherine Haney, Regional Administrator- Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. Brian Holian, Director, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike M/S 0-13H16 Rockville, MD 20852-2738 Ms. Audrey Klett, Project Manager (ONS)

(by electronic mail only)

U.S. Nuclear Regulatory Commission 11555 Rockville Pike M/S 0-0881 A Rockville, Maryland 20852 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Station