ML19011A109

Supplement to the Flooding Hazard Reevaluation Report

ML19011A109
Person / Time
Site:	Millstone
Issue date:	01/04/2019
From:	Mark D. Sartain Dominion Energy Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML19011A109 (3)

Text

• -Dominion Energy Nuclear Connecticut, Inc .

~ Dominion 5000 Dominion Boulevard, Glen Allen, V,A 23060 Dominion Energy.com January 4, 2019 P' Energy U.S. Nuclear Regulatory Commission Serial No.18-447 Attention: Document Control Desk NRA/MLW RO Washington, DC 20555 Docket Nos. 50-336 50-423 License Nos. DPR-65 NPF-49 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNITS 2 AND 3 SUPPLEMENT TO THE FLOODING HAZARD REEVALUATION REPORT On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued, "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 N~ar-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," to all power reactor licensees and holders of construction permits in active or deferred status. Flooding Recommendation 2.1 requires licensees to perform a flood hazard reevaluation and provide a final report documenting the results, as well as pertinent site information and detailed analysis.

In a letter dated March 12, 2015, Dominion Energy Nuclear Connecticut, Inc, (DENC) provided the Millstone* Power Station (MPS) Flooding Hazard Reevaluation Report (FHRR). The FHRR included both deterministic *and probabilistic storm surge analyses.

In a letter dated December 21, 2016, the NRC issued a summary of the NRC staff's assessment of the FHRR. The letter stated, "The NRC staff had been focusing its review on the deterministic methodology. During a November 3, 2016, teleconference held as part of the audit, the licensee informed the NRC staff that it intends to use the probabilistic storm surge analysis in its flood hazard reevaluation ... " and therefore did not include the staff's assessment of flooding due to storm surge.

On October 3, 2018, the NRC issued a Staff Assessment of Response to 10 CFR 50.54(f) Information Request-Flood-Causing Mechanism Reevaluation. The NRC staff assessment provided documentation supporting the staff's conclusions summarized in the December 21, 2016 letter. The staff assessment also stated, "The licensee's analysis of the storm surge flood-causing mechanism is not yet completed and is under ongoing review by staff. The NRC staff review of the storm surge hazard mechanism and assessment of plant response.will be finalized following submittal by the licensee of their final documentation of the analyses, which is currently anticipated in December 2018."

The purpose of this letter is to submit the documentation of the probabilistic MPS storm surge analyses by supplementing the relevant sections of the FHRR related to storm surge with the information provided in the enclosure to this letter.

Serial No.18-447 Docket Nos. 50-336/423 Supplement to the FHRR Page 2 of 3 If you have any questions regarding this information, please contact Michael Whitlock at (804) 273-3123.

Sincerely, Mark D. Sartain Vice President - Nuclear Engineering & Fleet Support COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Mark D. Sartain, who is Vice President - Nuclear Engineering & fleet Support of Dominion Energy Nuclear Connecticut, Inc. 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.

'[f~ day of J/)11uar1 , CRAIG D SLY Acknowledged before me this 2019.

Notary Public My Commission Expires: f)./3J /;O ~ Commonwealth of Virginia

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Reg.# 7518653 r~otablic My Commission Expires December 31, 2@.£ Commitments made in this letter: No new regulatory commitments

Enclosure:

Supplement to Dominion Flooding Hazard Reevaluation Report for Millstone Power Station Units 2 and. 3 in Response to 50.54(f) Information Request Regarding Near-Term Task Force Recommendatio n 2.1: Flooding

Serial No. 18-44 7 Docket Nos. 50-336/423 Supplement to the FHRR Page 3 of 3 cc: (electronic distribution)

U.S. Nuclear Regulatory Commission, Region I Regional Administrator 2100 Renaissance Blvd.

Suite 100 King of Prussia, PA 19406-2713 R. V. Guzman Senior Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C 2 11555 Rockville Pike Rockville, MD 20852-2738 F. G. Vega, P.E.

Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop_012F02 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station