ML15275A155

McGuire, Units 1 and 2 - Response to NRC Letter Dated August 27, 2015, Request for Additional Information Regarding License Amendment Request, Nuclear Service Water System Allowed Outage Time Extension

ML15275A155
Person / Time
Site:	McGuire, Mcguire
Issue date:	09/24/2015
From:	Capps S D Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
MNS-15-073, TAC MF2983, TAC MF2984
Download: ML15275A155 (13)

Text

DUKE Steven D. CappsDUKE Vice PresidentENERGYMcGuire Nuclear StationDuke EnergyMG01VP 1 12700 Hagers Ferry RoadHuntersville, NC 28078o: 980.875.4806f: 980.875.4809Steven.Capps@duke-energy.com10 CFR 50.90September 24, 2015Serial: MNS-1 5-073U.S. Nuclear Regulatory CommissionWashington, DC 20555-001ATTENTION: Document Control DeskDuke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station, Units 1 and 2Docket Nos. 50-369 and 50-370Renewed License Nos. NPF-9 and NPF-17Subject: Response to NRC letter dated August 27, 2015, "McGuire Nuclear Station, Units1 AND 2: Request for Additional Information Regarding License AmendmentRequest Nuclear Service Water System Allowed Outage Time Extension (TACNOS. MF2983 AND MF2984)"References:1. Duke Energy Letter dated June 30, 2015, "License Amendment Request for TemporaryChanges to Technical Specifications for Correction of an 'A' Train Nuclear Service WaterSystem (NSWS) Degraded Condition" (Agencywide Documents Access andManagement System (ADAMS) Accession No. ML15191A025).2. Nuclear Regulatory Commission (NRC) Letter dated July 27, 2015 "McGuire NuclearStation, Units 1 and 2 -Acceptance Review of License Amendment Request RE:Temporary Changes to Technical Specifications for Correction of Nuclear Service WaterSystem Degraded Condition (TAC NOS. MF6409 AND MF641 0)" (ADAMS AccessionNo. ML15202A661)3. Duke Energy Letter dated August 11, 2015, "Response to Request for AdditionalInformation Regarding License Amendment Request for Temporary Changes toTechnical Specifications for Correction of an 'A' Train Nuclear Service Water System(NSWS) Degraded Condition (TAC Nos. MF6409 and ME 6410)" (ADAMS AccessionNo. ML15247A066)4. NRC Letter dated August 27, 2015, "McGuire Nuclear Station, Units 1 AND 2: Requestfor Additional Information Regarding License Amendment Request Nuclear ServiceWater System Allowed Outage Time Extension (TAC NOS. MF2983 AND MF2984)"(ADAMS Accession No.ML15237A416)

US Nuclear Regulatory CommissionSeptember 24, 2015Page 2By letter dated June 30, 2015 (Reference 1), Duke Energy requested a license amendment forthe Renewed Facility Operating Licenses (FOL) and Technical Specifications (TS) for theMcGuire Nuclear Station, Units 1 and 2, to allow temporary changes to TS 3.5.2, EmergencyCore Cooling System (ECCS) -Operating; TS 3.6.6, Containment Spray System (CSS); TS3.7.5, Auxiliary Feedwater (AFW) System; TS 3.7.6, Component Cooling Water (CCW) System;TS 3.7.7, Nuclear Service Water System (NSWS); TS 3.7.9, Control Room Area VentilationSystem (CRAVS); TS 3.7.11, Auxiliary Building Filtered Ventilation Exhaust System (ABFVES),and TS 3.8.1, AC Sources- Operating.By letter dated August 11, 2015 (Reference 3), Duke Energy responded to NRC letter datedJuly 27, 2015 (Reference 2), request for additional information (RAI) needed for completion ofNRC staff review of the proposed LAR.By letter dated August 27, 2015 (Reference 4), the NRC provided Duke Energy a second RAIneeded for completion of the NRC staff review of the LAR. The enclosure provides DukeEnergy's responses to the RAI questions. Attachment 1 in the enclosure revises commitment13 and adds a new commitment 31 to the Regulatory Commitments described in Reference 1.The conclusions reached in the original determination that the June 30, 2013, LAR contains NoSignificant Hazards Considerations, and the categorical exclusion from performing anEnvironmental/Impact Statement have not changed as a result of the RAI responses inEnclosure the enclosurePursuant to 10OCFR50.91, a copy of this LAR has been forwarded to the appropriate NorthCarolina state officials.Please direct any comments or questions regarding this submittal to George Murphy at(980) 875-5715.I declare under penalty of perjury that the foregoing is true and correct. Executed onSeptember 24, 2015.Sincerely,Steven D. CappsEnclosure:Response to Request for Additional Information US Nuclear Regulatory CommissionSeptember 24, 2015Page 3cc wI/Attachments:V. M. McCreeAdministrator, Region IIU.S. Nuclear Regulatory CommissionMarquis One Tower245 Peachtree Center Ave., NE, Suite 1200Atlanta, GA 30303-1257J. ZeilerNRC Senior Resident InspectorMcGuire Nuclear StationG. E. Miller, Project ManagerU.S. Nuclear Regulatory Commission11555 Rockville PikeMail Stop 0-8 G9ARockville, MD 20852-2738W. L. Cox, Ill, Section ChiefNorth Carolina Department of Environment and Natural ResourcesDivision of Environmental HealthRadiation Protection Section1645 Mail Service CenterRaleigh, NC 27699-1 645 ENCLOSUREResponse to Request for Additional Information Response to Request for Additional InformationREQUEST FOR ADDITIONAL INFORMATIONBY THE OFFICE OF NUCLEAR REACTOR REGULATIONRELATED TO A LICENSE AMENDMENT REQUEST SUPPORTING CORRECTION OF ANUCLEAR SERVICE WATER SYSTEM DEGRADED CONDITIONDUKE ENERGY CAROLINAS. LLCMCGUIRE NUCLEAR STATION. UNITS 1 AND 2DOCKET NOS. 50-369 AND 50-370By letter dated June 30, 2015 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML15191A025), Duke Energy Carolinas, LLC (Duke Energy)submitted a license amendment request (LAR) to temporarily change McGuire Nuclear Station(MNS), Units 1 and 2, Technical Specifications (TSs) for correction of a degraded conditionaffecting the 'A' Train of the nuclear service water system (NSWS). The requested amendmentwould temporarily change the following TSs to allow the inoperability of the 'A' Train of theNSWS for a total of up to 14 days: TS 3.5.2, Emergency Core Cooling System (ECCS) -Operating; TS 3.6.6, Containment Spray System (CSS); TS 3.7.5, Auxiliary Feedwater (AFW)System; TS 3.7.6, Component Cooling Water (CCW) System; TS 3.7.7, Nuclear Service WaterSystem (NSWS); TS 3.7.9, Control Room Area Ventilation System (CRAVS); TS 3.7.11,Auxiliary Building Filtered Ventilation Exhaust System (ABEVES), and TS 3.8.1, AC Sources-Operating. The 'A' Train of the shared NSWS would be inoperable while the safety-relatedsupply from the MNS Nuclear Service Water Pond was drained and isolated to correct adegraded condition affecting that line.Based on the NRC staff's review of this amendment request, the NRC staff has determined thefollowing additional information is necessary to support completion of its technical review:SBPB-RAI-001The LAR included a potential activity to install a piping penetration in the drained section of theNSWS within the auxiliary building if required for personnel access to remove suspectedblockage. The LAR also included information indicating the opening in the pipe for personnelaccess establishes the potential for NSWS leakage into the auxiliary building. To ensureagainst the potential for significant leakage, the LAR indicated that the Standby Nuclear ServiceWater Pond (SNSWP) water source would be isolated by the installation of a bolted flange andthe Lake Norman water source would be isolated by closure of ORN-7A under proceduralcontrols. Dedicated personnel and procedures would be established to address excessiveleakage past the valve. However, the MNS Updated Final Safety Analysis Report includedinformation indicating the auxiliary building is a Category 1 structure that is sealed to provideprotection against external flooding. Although unlikely, the procedural control of valve 0RN-7Aposition creates the credible potential for inadvertent opening of the valve while the pipingpenetration in the auxiliary building is open that could cause flooding of the auxiliary buildingfrom Lake Norman.Please clarify how this approach is consistent with defense-in-depth, particularly the principal ofavoiding an over-reliance on programmatic activities. The programmatic control of the 0RN-7APage 2 of 5 Response to Request for Additional Informationvalve position and the programmatic response to significant valve leakage should have reliabilitycommensurate with the likelihood and consequences of significant leakage past valve 0RN-7Awith an opening in the pipe within the auxiliary building. The NRC staff requests additionalinformation that addresses these considerations. As appropriate, these considerations may beaddressed by eliminating the need for a piping penetration within the auxiliary building,establishing by analysis that the consequences of flooding through the auxiliary buildingpenetration would be small (e.g., passive barriers within the auxiliary building would protectessential equipment from flooding through that path), or providing independent additional pipingisolations (e.g., a freeze seal in the NSWS piping between valve ORN-7A and Lake Norman).Duke Energy Response to SBPB-RAI-0010RN-7A will be used as the isolation barrier between Lake Norman and the new NSWS pipingmanway in the auxiliary building. Isolation will be controlled via the plants clearance and tag outprocess. The tag out process requires Senior Reactor Operator (SRO) approval for changes inplant component configuration. For defense-in-depth, Operations will utilize the concurrent dualverification process that requires an additional parallel verification of plant/system conditions,hands on the correct component, and an understanding of the intent of actions prior to actualoperation of 0RN-7A. Additionally, control of the new manway will be under the clearance andtag out process for 0RN-7A such that 0RN-7A cannot be opened unless the manway is closed.The tag out process will place danger tags on the 0RN-7A actuator motor operator breaker aswell as the hand wheel. The tag out process will maintain the 0RN-7A actuator motor breakerlocked in the off position and the mechanical hand wheel will be locked closed with a restrainingdevice to prevent inadvertent operation via bumping of 0RN-7A.In summary, the programmatic control of 0RN-7A under the clearance and tag out programensures that ORN-7A will be maintained closed during periods when the new NSWS pipingmanway is open. This includes the tagging and locking of the Motor Control Center breaker for0RN-7A and the placement of a restraining device with a lock on the hand wheel of 0RN-7A.The reliability of this programmatic control will be enhanced by the addition of concurrent dualverification for any operation of 0RN-7A during the LAR activity, a step in the tag out checklistfor verification that the new NSWS manway is closed prior to opening ORN-7A.Zero leakage cannot be guaranteed for 0RN-7A. Prior to performing the activities described inthe LAR, the motor operator will be tested and adjusted for the optimum closure position andtorque for minimal seat leakage. If the new manway is required for access to remove theblockage, then prior to cutting the pipe for access, an evaluation of leakage will be performed tovalidate proper isolation and ensure that 0RN-7A leakage is within expected limits.0RN-7A is a motor operated butterfly valve with its actuator stem in the approximate center ofthe valve disk. This design (stem in center of disk), results in application of pressure on thebutterfly disk due to natural forces (head pressure of Lake Norman), which keeps the butterflydisk against its closed valve seat when the valve is in the closed position.A review of operating experience and of manufacturer information for failure modes andconcerns with valves like 0RN-7A has yielded no information that would challenge theexpectation for 0RN-7A to be a reliable isolation point for protection against unacceptableleakage into the auxiliary building while the auxiliary building NSWS manway is open. NoPage 3 of 5 Response to Request for Additional Informationcredible failures have been identified that would suggest a failure resulting in a leak scenariooutside the scope of discussion described in this response.During periods when the new NSWS manway is open, dedicated personnel havingcommunication to the main control room with procedures to continuously monitor and respondto 0RN-7A leakage will be in place. If leakage increases and reaches the pre-determined leakrate limit, the repair activity will be stopped, and the manway will be closed. If conditionsprevent the prompt closure of the manway, then operations will place the 'B' NSWS train inoperation, secure 'A' NSWS operations and isolate the 'A' NSWS train to stop the leakagewithin 30 minutes. Existing commitment 13 will be revised to include the additional actionsdescribed above.The Unit 2 Auxiliary Feedwater pumps and Auxiliary Shutdown Panel equipment are physicallylocated in the room where the new NSWS manway opening will be installed. This room drainsto the auxiliary building Ground Water Drainage (WZ) sump, which has the capability ofremoving up to 500 gpm via two 250 gpm capacity WZ pumps that have emergency powersupplies and are also located in the same room as 0RN-7A.The design basis flood elevation for the affected room is 12 inches above the floor elevation.The Auxiliary Feedwater pumps and Auxiliary Shutdown Panel are not affected by flooding untilwater level exceeds 20 inches above the floor elevation in the room.It would take approximately 21,000 gallons of water in the Unit 2 Auxiliary Feedwater pumproom to exceed the design basis flood level of 12 inches. It would take approximately thirtyminutes to reach this volume of water assuming that 0RN-7A leakage is 700 gpm with no creditfor mitigation by the WZ sump pumps. Leakage for 0RN-7A is not expected to exceed a worstcase leak rate of 50-100 gpm. Assuming a 0RN-7A seat leakage limit of 100 gpm, the timeavailable to isolate NSW would be approximately three and a half hours.If manway closure is not possible then leakage from 0RN-7A via the new manway could bestopped with the use of dedicated personnel and procedural guidance well within the timebefore exceeding the design basis flood elevation in the Unit 2 Auxiliary Feedwater pump roomof 12 inches.Page 4 of 5 Response to Request for Additional InformationSBPB-RAI-002The LAR describes activities and design features that provide protection against macro-foulingof the NSWS from Lake Norman (i.e., inspection of fish barrier) and the SNSWP (i.e., fishpopulation controls, fish population survey, and fish barrier). Please describe how thetimeliness of these activities in managing the potential for macro-fouling will be verified prior toremoving the SNSWP supply to 'A' NSWS Train from service.Duke Energy Response to SBPB-RAI-002Historically, the potential for macro-fouling at the Low Level Intake (LLI) structure is higherduring the months of July to August when the alewife fish are drawn to higher levels of dissolvedoxygen caused by a natural lake cycle with cold water in the hypo limnetic layers. BySeptember, the higher dissolved oxygen levels are gone, and the fish move out of the hypolimnetic layers. During the July to August period, McGuire monitors the fish movement withacoustic surveys performed weekly. In addition, underwater live cameras were installed in June2015 and are used to monitor fish concentrations in the area above the LLI structure.The activities discussed in the LAR will not be performed during the seasonal conditions thatcause alewife macro-fouling phenomena. Existing Regulatory Commitment 25 in Reference 1states: "Prior to entering the 14 day CT perform an evaluation to ensure that there will be noanticipated impact to 'A' NSWS water supply from the LLI from alewife fish the during 14 dayCT". This evaluation will review the timing of the LAR activities to ensure that they will not beperformed during the seasonal time interval (July through August) when the alewife fishcongregate at the LLI. The timing of the LAR activities is also bounded by existing RegulatoryCommitment 19, which excludes the performance of the LAR activities during the months ofJune through October due to the rise in potential for tornados.Page 5 of 5 ATTACHMENT 1Regulatory Commitments REGULATORY COMMITMENTSThe following table identifies those actions committed to by Duke Energy in this document. Anyother statements made in this licensing submittal are provided for informational purposes onlyand are not considered to be regulatory commitments. Please direct any questions you mayhave in this matter to George Murphy at 980-875-5715.#__ REGULATORY COMMITMENTS1 The 'A' Train NSWS pumps will remain running and aligned to Lake Norman duringthe extended CT until the system is ready for post maintenance testing.2 Any maintenance that is performed on the remaining portions of 'A' Train NSWSduring the period in which the 'A' NSWS from the SNSWP supply piping is not___available will be limited to a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time3 The 'B' Train NSWS will be placed in its ESFAS alignment to the SNSWP watersource with the 'B' Train pumps in standby prior to starting the LAR activity andremain in this alignment until the 'A' Train NSWS SNSWP water source is restoredand ready for post maintenance testing.4 Procedures will be established to provide an additional defense in depth contingencythat could be used in the event of an extremely low probability of a loss of the LakeNorman water source due to a seismic event. The procedures will ensure that systemoperation is maintained within design limits (less than or equal to 2 NSWS pumpsrunning on a header), control of maximum system flow, and that system configurationprevents interaction of the degraded equipment with the functional equipment.5 Fukushima Response FLEX modifications will be installed and the FLEX strategieswill be available for implementation as additional defense-in-depth on both units.6 During the period in which the 'A' NSWS suction path from the SNSWP is non-functional, no discretionary maintenance or discretionary testing will be planned onthe following:a. 1A EDGb. 2A EDGc. The 'A' Train of NSWS excluding the activities described in the LAR for the'A' Train NSWS piping to the SNSWP.d. The 'B' Train of NSWS, ECCS, CSS, AFW, CCW, CRAVS, ABFVES orthe EDGse. The switchyard and other offsite power sourcesf. The SSF7 A condition in which repairs could impact the ability of an SSC to perform its SafetyFunction would result in termination of activities. The inspection may identify acondition that cannot be resolved within the 14 day completion time. Should such acondition be identified then the system will be restored to its current OBDN condition.If the ROV survey presents any opportunities for a less intrusive or less timeconsuming solution for addressing the OBDN condition, then these opportunities willbe pursued, as appropriate.8 In an activity planned to be performed this summer separate from the 14 daycompletion time repair activity, 0RN-7A will be tested for leakage and adjusted ifnecessary to minimize leakage.9 In an activity planned to be performed this summer separate from the 14 daycompletion time repair activity the SNSWP isolation flange will be test fitted to the 'A'SNSWP pipe.Page 2 of 5 10 Procedure guidance will establish controls to limit evacuation air pressure to less thanIa predetermined value in order to prevent air intrusion into the operatingj NSWS.11 Dedicated personnel with procedure guidance will be provided to close the pathwayfrom the auxiliary building on the affected 'A' Train NSWS piping from the SNSWP inthe event of any of the following:* An Engineered Safety Feature (ESF) actuation* Entry into RP/0/A/5700/006 Natural Disasters* Entry into RP/O/A/5700/O07 Earthquake12 This activity will be controlled under the Infrequently Performed Test or Evolution(IPTE) process defined in Fleet Directive AD-OP-ALL-i106, "Conduct of InfrequentlyPerformed Tests or Evolutions", and Duke Energy's Work Management andExecution procedures.un.nticipate leaag..roedra.acios.il provide guidance to stop the..leakage.During periods when the new NSWS manway is open, dedicated personnel havingcommunication to the main control room with procedures to continuously monitor andrespond to 0RN-7A leakage will be in place. If leakage increases and reaches thepre-determined leak rate limit, the repair activity will be stopped, and the manway willbe closed. If conditions prevent the prompt closure of the manway, then operationswill place the 'B' NSWS train in operation, secure 'A' NSWS operations and isolatethe 'A' NSWS train to stop the leakage.14 If the second personnel access opening is necessary, then prior to the opening of thesystem an evaluation of leakage will be performed to validate proper isolation andthat leakage is within expected limits.15 McGuire will communicate with the Transmission Control Center (TCC) to ensure thatthe McGuire Control Room is notified in the event of potential grid disturbances inorder that an appropriate plant response can be formulated.16 The Work Control Center or OCC will monitor weather forecasts and radar during theactivities that require the NSWS piping personnel access points to be open to assessthe potential for severe weather conditions (tornado, thunderstorms).17 Training will be provided in accordance with the Systematic Approach to Training(SAT) process to Operations personnel on this TS change and the associatedevolution to inspect and correct the degraded condition in the 'A' NSWS supply pipingfrom the SNSWP.18 Operations will review applicable abnormal operating procedures related to theresponse to an earthquake, the loss of the Lake Norman and the loss of NSWS priorto making 'A' NSWS suction path from the SNSWP inoperable and each shift until 'A'Train NSWS operability is restored.19 The repair work on the NSWS 'A' Train suction from the SNSWP will be scheduledduring a period in which hurricanes and tornadoes have a lower likelihood ofoccurrence.20 The Outage Command Center (OCC) will be manned while performing the activitiesauthorized by this amendment.Page 3 of 5 21The following list of equipment will be protected:a. 'B' Train NSWSb. 1B EDGc. 2B EDGd. 1B ECCSe. 2B ECCSf. 1B CSSg. 2B CSSh. 1BAFWi. 2B AFWj. 1BCCWk. 2B CCWI. B CRAVSm. B ABEVESn. Auxiliary Building WZ Sump and equipment supporting function of sump22 If required to be installed the new personnel access opening to be located on the 'A'Train NSWS piping in the auxiliary building will be designed and installed inaccordance with the Engineering Change Process.23 Foreign Material Exclusion (FME) will be controlled during the proposed activities inaccordance with AD-MN-ALL-0002, Foreign Material Exclusion (FME). Any debrisresulting from the obstruction removal activity will be mechanically cleaned out beforethe system is closed for return to service per EME plan developed in accordance withthe above procedure. The system will be video inspected and reversed flushed fromthe LLI to the SNSWP with isolation to downstream components to force anysediment back to the SNSWP.24 Following 'A' Train NSWS restoration, testing will be performed to verify that the asleft NSWS performance meets or exceeds pre-activity performance including 'A' TrainNSW pump NPSH conditions.25 Prior to entering the 14 day CT perform an evaluation to ensure that there will be noanticipated impact to 'A' NSWS water supply from the LLI from Alewife fish the during14 day CT.26 The new personnel access piping opening (in the auxiliary building) will be controlledby using procedures developed or revised for this purpose to maintain positive controlof the opening and to prevent an unmonitored release.27 The ERAT program includes the option to use a SSA (Safety Significant Activity)code which will cause the risk condition color to be "YELLOW". MNS will use thiscode during the activities described in this LAR.28 Designated operators will be available to execute the manual actions associated withaligning the affected unit's 'A' Train NSWS pump to the 'B' NSWS SNSWP via the___Main Supply Crossover piping.29If the contingency personnel access opening is installed, then Security personnel willestablish the proper controls and compensatory measures prescribed by securityprocedures and the security plan.Page 4 of 5 30 In support of the contingency the following conditions will be established before thestart of activities in the LAR:* The 'A' valve (0RN-14A) will be opened prior to the evolution and power willbe removed from the valve operator.* The 'B' valve (0RN-15B) will be maintained closed with the ESFAS signalfrom each unit blocked prior to the evolution. Maintaining 0RN-1 5B closedwith power removed satisfies operability requirements for the 'B' Train NSWS.The 'B' valve (0RN-15SB) can be opened from the control room after power isrestored if conditions warrant the use of this contingency.31 Operations will utilize the concurrent dual verification process when operating0RN-7A.Page 5 of 5