ML15352A207

(PUBLIC)- Staff Assessment of Response to Request for Information Pursuant to 10 CFR 50.54(f) Flood-Causing Mechanisms Reevaluation (CAC Nos. MF1012, 1013 and 1014)

ML15352A207
Person / Time
Site:	Oconee
Issue date:	04/14/2016
From:	Boland A, Jennifer Davis Division of Operating Reactor Licensing, Japan Lessons-Learned Division
To:	Batson S Duke Energy Carolinas
Uribe J, NRR/JLD/ 415-3809
References
CAC MF1012, CAC MF1013, CAC MF1014
Download: ML15352A207 (4)

Text

OFFIC JAL USE ONLY SECURITY RELATED INFORMATION UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 14, 2016 Mr. Scott Batson Site Vice President, Ocon e Nuclear Station Duke Energy Carolinas, L C 7800 Rochester Highway Seneca, SC 29672-0752 1

SUBJECT:

OCONEE ~UCLEAR STATION , UNITS 1, 2, AND 3-STAFF ASSESSMENT OF RESPONS q TO REQUEST FOR INFORMATION PURSUANT TO 10 CFR 50.54(f) FLcpOD-CAUSING MECHANISMS REEVALUATION (CAC NOS .

MF1012, Mf 1013, AND MF1014) AND PATH FORWARD ON CONFIRMATORY ACTION LE TER

Dear Mr. Batson:

The purpose of this letter i~ to provide the results of the staff's review of the Flood Hazard Reevaluation Report and t<D communicate the NRC's approach to address the regulatory J

matters associated with thJ Confirmatory Action Letter related to flooding at Oconee Nuclear Station.

By letter dated March 12, 012, the U.S . Nuclear Regulatory Commission (NRC) issued a request for information pur . uant to Title 10 of the Code of Federal Regulations, Section 50.54(f)

(hereafter referred to as th~ 50.54(f) letter). The request was issued as part of implementing lessons-learned from the abcident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter reque~ted licensees to reevaluate flood-causing mechanisms using present-day methodologieiand guidance. By letter dated March 12, 2013 (Agencywide Documents Access and M nagement System (ADAMS) Accession No. ML13079A227), Duke Carolinas, LLC (Duke, the icensee) submitted its flood hazard reevaluation report (FHRR) for Oconee Nuclear Station , U its 1, 2 and 3 (Oconee) . Duke also provided supplemental information resulting from rEquests for additional information and audits. The supplemental information included the licr.nsee's revised FHRR for Oconee and was submitted on March 6, 2015 (ADAMS Accession 10. ML15072A099).

By letter dated September ~4 , 2015 (ADAMS Accession No. ML15239B261), the NRC staff transmitted to Duke a sum rr ary of the staff's review of the licensee's reevaluated flood-causing mechanisms. The enclbse~ staff assessment provides the documentation supporting the NRC staff's conclusions sumhia ized in that letter1 . As stated in that letter, the 2015 reevaluated flood hazard results for lloc! I intense precipitation; rivers and streams; and dam failure, were not bounded by the current pla t design-basis analyses. In order to complete its response to to the 50.5~! (f) letter, the licensee is expected to submit an integrated assessment or a focused evaluation as appropriate, to address these reevaluated flood hazards, as described in the NRC's Se tember 1, 2015, letter (ADAMS Accession No. ML15174A257). The I

The Enclosures trans nitted herewith contain Security-Related Information. When separate~ from the Enclosures, this document is decontrolled.

OFFICIAL USE ONLY SECURITY RELATED INFORMATION

OFFICIAL ~SE ONLY SECURITY RELATED INFORMATION NRC staff has determined hat Duke has appropriately completed steps 1 through 6 of the 10-1 step process described in nclosure 2 of the 50.54(f) letter. This closes out the NRC's efforts associated with CAC N~s. F1012, MF1013, and MF1014. New CAC numbers will be assigned for future NRC re iew of the new information submitted to address the revised flood hazards.

Flooding hazards at the 0 ~onee site have been the subject of significant interactions between the NRC and Duke prior to he 10 CFR 50.54(f) letter issued in response to the Fukushima Dai-ichi accident. Enclosure 2 f this letter provides a summary comparison of Duke's 2015 flood hazards evaluation and Du e's prior flood hazards evaluation docketed in 2010, relative to a postulated Jocassee dam f ilure. The NRC staff has determined that the 2010 licensee evaluation reflects a boLnd; ng flood hazard analysis for Oconee based on conservative assumptions. The 20151ev

• luation reflects a reasonable analysis that removes some conservatism from the 201 analysis, and is consistent with recent Commission direction regarding licensees' flobd ~azard reevaluation in response to the 50.54(f) letter. Therefore, the NRC staff concluded thrt t ~ e licensee's estimated flood levels at the ONS are considered reasonable and satisfy the nformation requests for each letter. Further, the staff concludes that the revised 2015 FHRR pr vides an acceptable alternative flood hazard analysis for ONS for the purpose of meeting the terms of the June 22, 2010, NRC Confirmatory Action Letter (CAL).

Following the completion of the associated flooding modifications by June 2016, the NRC will evaluate whether the term of the CAL have been satisfied.

By letter dated January 8, 4016, Duke submitted supplemental information regarding the external flooding hazards fd>r Oconee. In that letter, Duke indicated its intent to maintain in effect certain compensato~ I actions implemented in response to the CAL. The NRC views these actions as an import nt element in Duke's overall strategy to mitigate the risks associated with a potential failure of th Jocassee Dam . Also in that letter, you stated your intent to revise the Oconee Updated Final afety Analysis Report to reflect the results of the revised FHRR and the related actions taken b Duke to resolve external flooding issues, in accordance with forthcoming NRC guidance. Going forward , the NRC staff will address ongoing external flooding issues for Oconee r ithin the framework of the Fukushima Near-Term Task Force Recommendation 2.1 proc, ss, to ensure consistency in the staff's approach to addressing these issues for all plants.

OFFICIAL JUSE ONLY SECURITY RELATED INFORMATION

OFFICIAJ USE ON LY SECURtTY RELATED INFORMATION S.Batson If you have any questions, please contact Juan Uribe or Randy Hall at (301) 415-3809 and (301 ) 415-4032 respeqtive y, or via e-mail at Juan.Uribe@nrc.gov and Randy.Hall@nrc.gov, respectively.

Sincerely,

~4,J/'-MJ  :/?}/

Jack R. Davis, Director Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-269 , 50-2 O and 50-287

Enclosures:

1 . Staff Assessment of Flo d Hazard Reevaluation Report

2. Comparison of 2010 and 2015 Jocassee Dam Failure Evaluations cc w/o encl : Distribution vi Listserv Ol'l'IClil.L I SE ONLY S&CURITV RELATED INFORMATION

Pkg. ML15356A161; Letter ML15352A207 (PUBLIC); Enclosures 1&2 ML15356A158 (NON-PUBLIC) *via email OFFICE NRR/JLD/JHMB/PM* NIRR/JLD/LA NRO/DSENRHM1/BC* NRR/JLD/JHMB/BC NRR/DRND NAME JUribe Silent I

CCook MS hams JGiitter DATE 03/24/2016 0 /07/2016 03/30/2016 03/24/2016 04/03/2016 I

OFFICE NRR/DE/D (A) OGC (NLO) NRR/DORUD NRR/JLD/D NAME MBailey (MJRoss-Lee for) B. Harris ABoland (E. Benner for) JDavis (G.Bowman for)

DATE 04/05/2016 0-' /04/2016 04/11/2016 04/14/2016