ML11228A199

McGuire, Unit 1 & 2, Supplemental Response to Request for Additional Information Regarding a Revision to Commitment in Response to Notice of Violation EA-08-220 (NRC Inspection Report Nos. 05000369/2008009 and 05000370/2008009)

ML11228A199
Person / Time
Site:	McGuire, Mcguire
Issue date:	07/28/2011
From:	Repko R T Duke Energy Carolinas
To:	Document Control Desk, NRC/RGN-II, NRC/RGN-III
References
EA-08-220 IR-08-009
Download: ML11228A199 (4)

See also: IR 05000369/2008009

Text

1WDukeO EnergyREGIS T. REPKOVice PresidentMcGuire Nuclear StationDuke EnergyMG01 VP / 22700 Hagers Ferry Rd.Huntersville, NC 28078980-875-4111980-875-4809 faxregis. repko@duke-energy. cornJuly 28, 2011U.S. Nuclear Regulatory CommissionDocument Control DeskWashington, DC 20555-001Subject:Duke Energy Carolinas, LLCMcGuire Nuclear Station, Units 1 and 2Docket Nos. 50-369 and 50-370Supplemental Response to Request for Additional Information regarding arevision to Commitment in response to Notice of Violation EA-08-220 (NRCInspection Report Nos. 05000369/2008009 and 05000370/2008009)By letter dated December 7, 2009, McGuire responded to an NRC request for additionalinformation dated November 6, 2009.Enclosure 1 of the December 7, 2009 submittal addressed the request for information regardingcompensatory and other measures in place to assure operability of the Nuclear Service WaterSystem (NSWS) in case of a macro-fouling condition and provided justification for why thosemeasures were deemed adequate. Enclosure 2 provided a discussion of the schedule ofactivities to be completed and why these measures represented the first available opportunity torestore compliance.Please find attached a supplemental response to modification 2 -Pipe from Strainer Backwashto Groundwater Drainage System (WZ) Sump and modification 3 -Backwash pump dischargingto the RN system Return Header as documented in Enclosure 2 of the December 7, 2009submittal.This submittal contains no new regulatory commitments.Please direct any questions you may have in this matter to Kay L. Crane at (980) 875-4306.Regis T. Repkowww. duke-energy. con?

July 28, 2011Nuclear Regulatory CommissionPage 2V. M. McCreeRegional Administrator, Region IIU.S. Nuclear Regulatory CommissionMarquis One Tower245 Peachtree Center Ave., NE, Suite 1200Atlanta, GA 30303-1257John ZeilerNRC Senior Resident InspectorMcGuire Nuclear StationJ. H. Thompson, Project ManagerU.S. Nuclear Regulatory Commission11555 Rockville PikeMail Stop 0-8 G9ARockville, MD 20852-2738 AttachmentEnclosure 2 of the December 7, 2009 letter stated in part:"To address the operable but degraded non conforming condition McGuire is in the process ofdeveloping three modifications for the Nuclear Service Water System (NSWS). The threemodifications are described as follows:* The first modification includes the addition of an assured air source to the backwashinlet valves to allow the NSWS Strainers to automatically back wash for at least 8hours into a loss of Instrument air (VI) event. This will remove the time criticaloperator actions required to operate the back wash supply inlet valve during thepotential loss of VI event." The second modification re-routes the backwash return piping to provide a lessrestrictive flow path for backwash return to the Ground Water (WZ) sump via manualoperator actions." The third modification installs a new Nuclear Safety Related back wash dischargepump to the NSWS Return Header for each train of the NSWS. This phase ensuresthere will be no depletion of the SNSWP by routing the discharge back to thebackwash source of water."1- Assured Air to Strainer Backwash Inlet AOV completion in August 2010These modifications have been fully implemented.2 -Pipe from Strainer Backwash to WZ Sump completion in July 2011Enclosure 2 of the December 7, 2009 letter stated in part:"The scope of this Engineering Change includes flow modeling (to validate debris transport),piping support/stress analysis and design/fabrication of a basket to capture debris from thestrainer backwash outlet."The following status/change is provided:The portion of the modification to generate a flow model, perform piping support/stress analysis,and re-route the discharge piping to the groundwater sump has been completed on all fourtrains of the NSWS. Operational control of this flow path for all four trains has been accepted byOperations.The portion of the modification related to the design/fabrication of a basket to capture debrisfrom the strainer backwash outlet has not been completed. The design and fabrication of thebasket will be completed within the final phase (Modification #3) of the Backwash DischargePump installation which is scheduled for completion by December, 201 Attachunent3 -Backwash pump discharging to the RN System Return Header completion inDecember 2012Enclosure 2 of the December 7, 2009 letter included the following as part of the scope of thethird modification:"Delete the NSWS backwash return Air Operated Valve (1/2RN-22A, -26B) and inappropriatebackwash to WZ Sump piping, while maintaining the flow path for mimicking NSWS to theauxiliary feed water system flow for NSWS flow balance. Delete Safety Injection signal tothese valves. Also, remove the air operators and install manual hand wheels for 1/2RN-23/27."During final design development the following changes were identified:" Removing the air operators and installing manual hand wheels for 1/2RN 23/27 is notrequired. By removing 1/2 RN-22A, -26B, the flow path from the Condenser CirculatingWater (RC) discharge to the NSWS strainers will no longer exist. Therefore modificationof the air operators on 1/2RN 23/27 is no longer required for returning the straineroperation to its current licensing basis requirements." An interaction was identified between the 1A and 2A NSWS backwash pump dischargeflow path and the Standby Shutdown Facility (SSF) make-up to the Auxiliary Feedwater(CA) pump. For all plant conditions except for a Unit 1 Appendix R fire while operatingfrom the SSF, the backwash discharge pump will discharge to the NSWS return header.For this unique Unit 1 Appendix R event, the train 1A and 2A backwash dischargepumps will return to the RC discharge header. The flow path to the RC dischargeheader can potentially result in SNSWP depletion during the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Appendix R event.A preliminary assessment concluded the possible SNWSP impact is acceptable.