ML13217A002

Oconee, Units 1, 2, & 3 - Additional Information Regarding License Amendment Request to Clarify the Application of the 45-day Completion Time of Technical Specification 3.8.1 Required Action C.2.2.5 License Amendment Request No. 2012-14, Su

ML13217A002
Person / Time
Site:	Oconee
Issue date:	07/26/2013
From:	Batson S L Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13217A002 (6)

Text

DU.KE Scott L. BatsonENERGY. Vice President Oconee Nuclear StationDuke EnergyONOIVP 1 7800 Rochester HwySeneca, SC 29672o: 864.873.3274 f 864.873.4208 Scott.Batson@duke-energy.com 10 CFR 50.90July 26, 2013U. S. Nuclear Regulatory Commission Attn: Document Control DeskWashington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLCOconee Nuclear Station (ONS), Units 1, 2, and 3Docket Numbers 50-269, 50-270, and 50-287Additional Information Regarding License Amendment Request to Clarify theApplication of the 45-day Completion Time of Technical Specification 3.8.1Required Action C.2.2.5License Amendment Request (LAR) No. 2012-14, Supplement 2On October 30, 2012, Duke Energy Carolinas, LLC (Duke Energy) submitted a LicenseAmendment Request (LAR) requesting the Nuclear Regulatory Commission (NRC) approve aTechnical Specification (TS) change to allow the 45-day Completion Time of TS 3.8.1 RequiredAction C.2.2.5 to be applied cumulatively over a 3-year time period for each Keowee Hydro Unit(KHU). By letter dated June 17, 2013, the NRC requested Duke Energy to submit additional information associated with the LAR. Duke Energy responded to this request by letter datedJuly 16, 2013. During conference calls with NRC staff on July 9 and July 11, Duke Energyagreed to provide additional information to address the risk significance of dual KHU outages.The enclosure provides the requested information.

This license amendment is needed to allowwork associated with the Protected Service Water (PSW) System tie-in to the KHU emergency power to proceed on schedule.

This work is scheduled to begin on September 3, 2013;therefore, approval no later than August 15, 2013, is requested.

There are no newcommitments being made as a result of this letter.If there are any additional questions, please contact Boyd Shingleton, ONS Regulatory Affairs,at (864) 873-4716.

www.duke-energy.com Nuclear Regulatory Commission License Amendment Request No. 2012-14, Supplement 2July 26, 2013 Page 2I declare under penalty of perjury that the foregoing is true and correct.

Executed onJuly 26, 2013.Sincerely, Scott L. BatsonVice President Oconee Nuclear StationEnclosure Response to NRC Request for Additional Information Regulatory Commission License Amendment Request No. 2012-14, Supplement 2July 26, 2013 Page 3cc w/

Enclosure:

Mr. Victor McCree, Regional Administrator U. S. Nuclear Regulatory Commission

-Region IIMarquis One Tower245 Peachtree Center Ave., NE, Suite 1200Atlanta, GA 30303-1257 Mr. John Boska, Senior Project Manager(by electronic mail only)Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 11555 Rockville PikeMail Stop O-8G9ARockville, MD 20852Mr. Ed CroweSenior Resident Inspector Oconee Nuclear SiteMs. Susan E. Jenkins, ManagerRadioactive

& Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control2600 Bull St.Columbia, SC 29201 ENCLOSURE Duke Energy Response toNRC Request for Additional Information (RAI)

EncIpsure

-Duke Energy Response to NRC RAILicense Amendment Request No. 2012-14, Supplement 2July 26, 2013 Page 1Background Information NRC requested Duke Energy to respond to 8 RAI questions by letter dated June 17, 2013. Duringphone calls to discuss Duke Energy responses to the RAI questions on July 9 and 11, 2013, NRCcontinued to express concern that allowing the 45-day Completion Time of Technical Specification (TS) Required Action C.2.2.5 to be applied cumulatively over a three year period versus one timeover a three year period will result in an additional number of extended dual Keowee Hydro Unit(KHU) outages.

Duke Energy's response to RAI 8, which was intended to address this concern,proposed to restrict the cumulative time allowed in dual KHU outages by adding a secondCompletion Time to TS 3.8.1 Required Action H.2 that restricts the time allowed in Condition Hover a three year period to 240 cumulative hours when in the 45 day Completion Time of RAC.2.2.5.

This is equivalent to the maximum time that could be incurred during one continuous 45-day outage for each KHU with two 60-hour dual KHU outages (one to isolate a KHU formaintenance and one to restore a KHU from maintenance).

Limiting the dual KHU outage time inthis manner precludes increasing the duration of dual KHU outage time over what is currently allowed.The NRC Staff acknowledged that the proposed change limits the time in a dual KHU outage butindicated that NRC would like to get an understanding of the risk significance of these dual KHUoutages and asked Duke Energy to calculate the Incremental Conditional Core DamageProbability (ICCDP) and Incremental Conditional Large Early Release Probability (ICLERP)incurred due to 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> of dual KHU outage time over a three year period. Duke Energy agreedto perform this calculation using a method identified as acceptable by NRC Staff.Summary of PRA resultsThe risk evaluation was conducted for the dual KHU outage configuration using the following assumptions:

" Maintenance unavailability values for all plant systems were set to zero for all plantsystems except for Keowee.* The tornado initiating event frequency was set to zero and the weather-related Loss ofOffsite Power (LOOP) initiating frequency was reduced to reflect risk management actionsthat preclude entering a dual KHU outage when the potential for severe weather existsduring the outage period. This assumption is based on administrative controls and riskmanagement plans that require review of the weather forecast prior to the beginning of thedual KHU outage and do not allow the outage to begin if any weather conditions arepredicted that could adversely affect the availability of offsite power from the switchyard.

" Operator actions in the Probabilistic Risk Assessment (PRA) model to align backup powerfrom transformer CT5 following a LOOP event were removed from the model. Theseactions are not required during the Keowee outages because the Standby Buses will beenergized from a Lee Combustion Turbine (LCT) using a dedicated transmission line asrequired by TS 3.8.1 Condition H.* Seismic events were neglected from the analysis.

-Encl9sure

-Evaluation of Proposed ChangeLicense Amendment Request No. 2012-14, Supplement 2July 26, 2013 Page 2The analysis results determined that a total dual KHU unit outage time of 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> (10 days)corresponds to an ICCDP of approximately 6E-08. Approximately half of this risk contribution wasdue to LOOP initiating events and half from fire-related events. When this unavailability isaveraged over a 3 year period, the equivalent ICCDP is 2E-08 which represents an insignificant impact on average annual plant risk.The ICLERP value was not specifically computed.

However, it was concluded that the ICLERPimpact is also insignificant given that the Large Early Release Frequency (LERF) is a subset of theCore Damage Frequency (CDF) and that the ICCDP value is very low.