ML12319A075

Catawba, Units 1 and 2, Proposed Technical Specifications (TS) and Bases Amendment TS and Bases 3.7.8, Nuclear Service Water System (Nsws) Response to NRC Request for Additional Information (RAI) (TAC Nos. ME7659 and ME7660)

ML12319A075
Person / Time
Site:	Catawba
Issue date:	11/12/2012
From:	Henderson K Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC ME7659, TAC ME7660
Download: ML12319A075 (24)

Text

Duke KELVIN HENDERSONCatawba Nuclear StationaEnergy Site Vice PresidentCarolinasDuke Energy Carolinas, LLC4800 Concord Rd.York, SC 29745803-701-4251November 12, 2012 10 CFR 50.90U.S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, D.C. 20555Subject: Duke Energy Carolinas, LLC (Duke Energy)Catawba Nuclear Station, Units 1 and 2Docket Numbers 50-413 and 50-414Proposed Technical Specifications (TS) and Bases AmendmentTS and Bases 3.7.8, Nuclear Service Water System (NSWS)Response to NRC Request for Additional Information (RAI)(TAC Nos. ME7659 and ME7660)References: 1. Letters from Duke Energy to the NRC, same subject, datedNovember 22, 2011 and July 9, 2012.2. Letter from the NRC to Duke Energy, same subject, dated October 9,2012.Reference 1 constitutes Duke Energy's request for amendments to the Catawba FacilityOperating Licenses and TS to modify the subject TS and Bases to allow singledischarge header operation of the NSWS (Duke Energy designation "RN") for a timeperiod of 14 days. The requested change will facilitate future maintenance of the Unit 2NSWS discharge headers in the Auxiliary Building. In Reference 2, the NRCtransmitted additional RAIs associated with this amendment request. The purpose ofthis letter is to provide responses to these RAls. The attachment to this letter providesthe responses. The format of each response is to restate the RAI question, followed bythe associated response.The original regulatory evaluation contained in Reference 1 is unaffected as a result ofthis RAI response supplement. As discussed in a telephone conference call betweenDuke Energy and the NRC on September 20, 2012, there is one regulatory commitmentassociated with this RAI response supplement. The pending procedural controls toprevent and mitigate the effects of flooding as discussed in the responses toQuestions 3 and 4 of the attachment represent a regulatory commitment.Pursuant to 10 CFR 50.91, a copy of this RAI response supplement is being sent to theappropriate State of South Carolina official.www. duke-energy. com U.S. Nuclear Regulatory CommissionPage 2November 12, 2012Inquiries on this matter should be directed to L.J. Rudy at (803) 701-3084.Very truly yours,Kelvin HendersonLJR/sAttachment U.S. Nuclear Regulatory CommissionPage 3November 12, 2012Kelvin Henderson affirms that he is the person who subscribed his name to theforegoing statement, and that all the matters and facts set forth herein are true andcorrect to the best of his knowledge.#KelnoHendeirson, S-e Vice Pr-esidentSubscribed and sworn to me: j!.a. 1 2... 0 / 2.DateNotary PublicMy commission expires: C_' ) III 2_ I -7DateSEAL U.S. Nuclear Regulatory CommissionPage 4November 12, 2012xc (with attachment):V.M. McCreeRegional AdministratorU.S. Nuclear Regulatory Commission -Region IIMarquis One Tower245 Peachtree Center Ave., NE Suite 1200Atlanta, GA 30303-1257G.A. Hutto, IIISenior Resident Inspector (Catawba)U.S. Nuclear Regulatory CommissionCatawba Nuclear StationJ.H. Thompson (addressee only)NRC Project Manager (Catawba)U.S. Nuclear Regulatory CommissionOne White Flint North, Mail Stop 8-G9A11555 Rockville PikeRockville, MD 20852-2738S.E. JenkinsManagerRadioactive & Infectious Waste ManagementDivision of Waste ManagementSouth Carolina Department of Health and Environmental Control2600 Bull St.Columbia, SC 292010 ATTACHMENTRESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION (RAI)

REQUEST FOR ADDITIONAL INFORMATIONBY THE OFFICE OF NUCLEAR REACTOR REGULATIONREGARDING LICENSE AMENDMENT RELATED TOREVISION OF THE TECHNICAL SPECIFICATION 3.7.8 TO ALLOWSINGLE DISCHARGE HEADER OPERATION OF THE NUCLEAR SERVICE WATER SYSTEMFORA TIME PERIOD OF 14 DAYSCATAWBA NUCLEAR STATION, UNITS 1 AND 2DOCKET NOS. 50-413 AND 50-414By letter dated November 22, 2011, (Agencywide Document Access and ManagementSystem Accession No. ML 11 327A1 49), Duke Energy Carolinas, LLC (Duke Energy, thelicensee), submitted a proposed license amendment request (LAR) in the form of changesto the Technical Specifications (TSs) for Catawba Nuclear Station, Units 1 and 2. Theproposed LAR would revise TS 3.7.8 to allow single discharge header operation of theNuclear Service Water System (NSWS) (Duke Energy designation "RN") for a time periodof 14 days.To complete its review, the U.S. Nuclear Regulatory Commission (NRC) staff requests thefollowing additional information:1. In the response to request for additional information (RAI) question 7, thelicensee stated that in the event of a failure of the common discharge line, thereturn to Lake Wylie can be realigned from the Control Room. 'The licensee didnot address what they would do to the supply side to NSWS if this eventoccurred.Duke Energy Response:In the event of a failure of the in-service common discharge line, the supply sideof the NSWS will be realigned to Lake Wylie, so that both the suction anddischarge of the NSWS will be aligned to Lake Wylie. Alignment of the NSWS intoand out of the Single Discharge Header alignment will be controlled by approvedstation procedures, including NSWS Operating Procedures (OP) and AbnormalOperating Procedures (AP).1

2. The licensee is not consistent and clear as to which motor operated valves willhave power removed.a. The description on Attachment 1, page 3, is not consistent with thefigures and notes on Attachment 1, pages 5 and 6.b. The description for general design criterion (GDC) 44 on Attachment 1,page 11, does not define which valves have power removed.c. Attachment 1, pages 18, 19, and 21 have only the crossover valves withpower removed, whereas the associated figures on Attachment 1, pages20 and 22, have additional valves with power removed, i.e. returnisolation valves.d. The conclusion section in Attachment 1, page 23, is equally unclear bynot stating any specific valves will have power removed.e. Attachment 1, page 30, in the probabilistic risk assessment (PRA)section, is unclear regarding which valves have power removed.f. The licensee response to RAI question 7b states that the crossovervalves, the discharge isolation valve for the out of service NSWS train,and the discharge valve for the in-service NSWS train all will have thepower removed.Duke Energy Response:a. -f. The NSWS motor operated valves which are described in the NSWS SingleDischarge Header alignment License Amendment Request are positionedand powered as follows with Train A discharge isolated:1 RN63A Closed, power removed1 RN58B Open, power removed1RN53B Open, power removed1RN54A Open, power removed1RN843B Closed, powered1RN57A Closed, powered2RN148A Closed, power removed*The NSWS motor operated valves which are described in the NSWS SingleDischarge Header alignment License Amendment Request are positionedand powered as follows with Train B discharge isolated:1RN58B Closed, power removed1RN63A Open, power removed2 1 RN53B Open, power removed1 RN54A Open, power removed1RN843B Closed, powered1RN57A Closed, powered2RN229B Closed, power removed**The NSWS motor operated valves associated with the Containment SpraySystem heat exchangers on Unit 1 and Unit 2 (1RNI48A, 1RN229B,2RN148A, and 2RN229B) are normally closed. When NSWS Train Adischarge is isolated for the NSWS Single Discharge Header alignment,2RN148A will be closed with power removed. Likewise, when NSWS TrainB discharge is isolated for the NSWS Single Discharge Header alignment,2RN229B will be closed with power removed.3. In the licensee's response to RAI question 10, it stated that any passive leakageon valves 1 RN63A or 1 RN58B will be addressed depending on the amount ofleakage. When each valve is closed for the planned maintenance described inthe submittal, discuss the effects of complete valve failure or an operator errorwhich opens the valves. What equipment in the Auxiliary Building could getsplashed by incoming water and discuss the effects loss of the wettedequipment?Duke Energy Response:Failure of 1 RN63A or I RN58BComplete failure of 1RN63A or 1RN58B when the valve is closed can beaddressed by looking at the valve failure modes. A review of industry operatingexperience (OE) has shown that the primary failure mode of this type of butterflyvalve is the separation of the disc from the valve stem, usually due to a failure ofthe disc to stem taper pins. Other failure modes described in industry OE areassociated with a failure of the valve stem to remain mechanically connected tothe gearbox (i.e., shaft key, whereby the gearbox and motor operator rotate butthe disc does not).It is not credible for any of these failures to occur when the valve is closed andthe disc, stem, gearbox, and motor operator are not moving. If a tapered pin orstem to gearbox failure were to occur while the valve is being repositioned to theclosed position, then the valve disc will likely not close fully. The valve seatcould fail during disc repositioning.All of these failures would impact the ability of the piping to be drained anddepressurized, and released for work. If any of these failures occur while thevalve is being repositioned to the closed position and the valve went to the fullyclosed position, there would be no plausible way for the disc to reposition to theopen position due to the valve construction, as described previously. Valve discto stem taper pins on 1 RN63A and 1 RN58B can be verified to be installed frominside the pipe. If taper pins are intact, there is no credible mechanical failure3 that could cause disc and stem separation and disc repositioning once the valveis closed. The construction of the valve is such that the disc is centered on thevalve stem, and the valve body has an integral stop so the disc cannot rotatethrough the seat. It is not credible for any of these failures to occur when thevalve is closed and the disc, stem, gearbox, and motor operator are not moving.If a tapered pin or stem to gearbox failure were to occur while the valve is beingrepositioned to the closed position, then the valve disc will likely not close fully.In summary, valve failures typically occur when the isolation valve isrepositioned. If a failure were to occur, it would be evident because the pipingcould not be effectively isolated and drained, and the piping could not be releasedfor work because isolation could not be effectively accomplished.Operator error resulting in the opening of IRN63A or IRN58BValves 1 RN63A and 1 RN58B will be closed with power removed when theirassociated NSWS Train is out of service. In order for 1RN63A or IRN58B to beinadvertently repositioned, multiple operators would have to make multipleerrors. The Safety Tagging process requires multiple Operations personnel,including a Senior Reactor Operator, to clear tags and return equipment toservice. Additionally, valves 1RN63A and 1RNP19 will have locks and red tagsinstalled on the handwheels when the NSWS Train A return header is isolated, sothat personnel do not inadvertently manually operate the valves. Likewise, whenthe NSWS Train B return header to the SNSWP is isolated for Single DischargeHeader alignment, valves 1RN58B and 1RNP20 will have locks and red tagsinstalled on the handwheels. The installation and removal of locks on thehandwheels will be controlled by station procedures.The above measures ensure that it will not be possible for a single operator tomake a single error to reposition either 1 RN63A or 1 RN58B while in the NSWSSingle Discharge Header alignment.Equipment qualification and submergence qualificationIn the unlikely event that a failure of 1 RN58B or I RN63A were to occur, acalculation of the buried 42-inch piping downstream of 1 RN58B or I RN63A andthe 10-inch buried NSWS piping from the diesel generators shows that the totalvolume of NSWS that could drain into the Auxiliary Building is approximately170,000 gallons. The equipment in the affected rooms of the Auxiliary Building onthe 577' elevation, 560' elevation, 543' elevation, and 522' elevation has previouslybeen analyzed and qualified for the consequences of pipe rupture, including atleast 6 inches of submergence. If the entire 170,000 gallons were to drain to the522' elevation, it would drain to the Residual Heat Removal/Containment SpraySump. This sump has a capacity of approximately 218,000 gallons before thenuclear safety related RHR minimum flow instrumentation could be impacted.Additionally, there are floor drains which could affect the Auxiliary FeedwaterSump. The flow rate into this sump is limited by piping, and is approximately 250gpm. The AFW sump capacity is calculated to be approximately 23,675 gallons at4 the 544' 6" elevation, where water begins to overflow the curb into the AFW pumppits. Based on this flow rate and capacity, the time required for operators to takeaction per the Abnormal Operating Procedure for flooding and address a failure of1RN58B, IRN63A, 1RNP19, or IRNP20 is approximately 90 minutes. Thisassumes that 100% of the water reaching the AFW pump room overflows into theroom up to the 544' 6" level. No credit is taken for the Liquid Radwaste Systemsump pumps, although each of the two sump pumps is rated at 50 gpm.In summary, the total volume of the 42-inch and 10-inch NSWS buried dischargepiping to the SNSWP that could drain into the Auxiliary Building was calculatedabove at approximately 170,000 gallons. The volume of the Residual HeatRemoval/Containment Spray Sump is greater than the piping volume; therefore,the RHR miniflow instrumentation would not be submerged if IRN58B or IRN63Awere to open while the NSWS is aligned in the Single Discharge Headeralignment. To address the impact on the AFW sump, operators will have to takeaction per the station Abnormal Operating Procedure on flooding within 90minutes. This procedure will specifically address the NSWS while aligned in theSingle Discharge Header alignment.4. In the licensee's response to RAI question 10, they stated that valves 1RNP19and 1 RNP20 have redundant isolation valves that could be repositioned toisolate valve failure and mitigate flooding. Describe what valves could berepositioned and discuss the effects of flooding that could occur until theredundant valves are closed. How long would it take to shut the redundantvalve(s)?Duke Energy Response:Failure of 1RNP19 or IRNP20As discussed above, valve failures typically occur when the isolation valve isrepositioned. If a failure were to occur, it would be evident because the pipingcould not be effectively isolated and drained, and the piping could not be releasedfor work because isolation could not be effectively accomplished.Operator error resulting in the opening of 1RNPI9 or 1RNP20Valves 1RNP19 and 1RNP20 are manual valves which will be closed and have redtags on their handwheels with their associated NSWS Train out oiF service. Inorder for 1RNP19 and 1RNP20 to be inadvertently repositioned, multiple operatorswould have to make multiple errors. The Safety Tagging process requiresmultiple Operations personnel, including a Senior Reactor Operator, to clear tagsand return equipment to service. In addition, when the NSWS Train A returnheader to the SNSWP is isolated for Single Discharge Header alignment, valves1RN63A and 1RNP19 will have locks and red tags installed on the handwheels, sothat personnel do not inadvertently manually operate the valves. Likewise, whenthe NSWS Train B return header to the SNSWP is isolated for Single DischargeHeader alignment, valves 1RN58B and 1RNP20 will have locks and red tags5 installed on the handwheels. The installation and removal of locks on thehandwheels will be controlled by station procedures.The above measures ensure that it will not be possible for a single operator tomake a single error to reposition either 1RNP19 or IRNP20 while ýin the NSWSSingle Discharge Header alignment.Redundant isolation valvesIn the unlikely event that a failure of 1RNP19 or IRNP20 were to occur, the flowrate through the open isolation valve could be in the 15,000 to 20,000 gpm range,assuming that one Nuclear Service Water pump is in service. To !isolate thisfailure, one of the return header crossover valves 1 RN53B or 1 RN54A would haveto be closed. Both of these valves will be open with power removed for the NSWSSingle Discharge Header alignment, so the station Abnormal Operating Procedurefor flooding will direct the restoration of power to either valve, and the manualand automatic operation to place either valve in the closed position. Additionally,the Abnormal Operating Procedure for flooding will direct the closing of theappropriate motor operated supply isolation valve from the Control Room toisolate flow to the NSWS Train IA or 1B, as appropriate. The timeframe forisolation of the failure depends upon the time it takes for operators to diagnosethe failure. The motor operated supply isolation valve is positioned from theControl Room. The effects of flooding on equipment in the Auxiliary Buildinguntil these redundant isolation valves are closed have been discussed previouslyin the response to Question 3.5. The RAI question 12 discussed inconsistencies in the licensee's submittal. In itsresponse, the licensee still appears to have inconsistencies. The licensee statesthat both trains of NSWS are OPERABLE [conflicts with the table on Attachment1, page 17]. That would mean that the limiting condition of operation (LCO) forTS 3.7.8 is met and that a new condition C would not be applicable. You cannotbe in a TS Condition and meet the LCO at the same time. You cannot have theNSWS discharge header inoperable with the corresponding NSWS trainOPERABLE. Note the updated final safety analysis report in Section 9.2.1.2.4"ensures two independent, redundant supplies and returns, satisfying the singlefailure criteria."Duke Energy Response:Refer to the revised reprinted TS and TS Bases pages which now indicate that theaffected NSWS train is inoperable while in the single Auxiliary Buiilding dischargeheader configuration.6. Discuss why notes [similar to NOTES 1 and 2 of Required Action A.1] are notprovided for Required Action C.1.6 Duke Energy Response:Notes 1 and 2 of Required Action A.1 state the following:1. Enter applicable Conditions and Required Actions of LCO 3.8.1, "ACSources-Operating," for emergency diesel generator made inoperable byNSWS.2. Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCSLoops-MODE 4, " for residual heat removal loops made inoperable byNSWS.Proposed Condition C contains the following three Notes:1. Entry into this Condition shall only be allowed for Unit I and for pre-planned activities as described in the Bases of this Specification. Entryinto this Condition shall not be allowed while Unit 2 is in MODE 1, 2, 3, or 4.2. Immediately enter Condition A of this LCO if one or more Unit I requiredNSWS components become inoperable while in this Condition and oneNSWS train remains OPERABLE.3. Immediately enter LCO 3.0.3 if one or more Unit I required NSWScomponents become inoperable while in this Condition and no NSWS trainremains OPERABLE.The proposed Condition C Bases discussion for these three Notes is as follows:Condition C is modified by three Notes. Note I states that entry into thisCondition shall only be allowed for Unit I and for pre-planned activities asdescribed in the Bases of this Specification. Condition C is only allowed to beentered in support of planned maintenance or modification activities associatedwith the Auxiliary Building discharge header that is taken out of service. Anexample of a situation for which entry into this Condition is allowed isrefurbishment of an Auxiliary Building discharge header. Entry into thisCondition is not allowed in response to unplanned events or for other eventsinvolving the NSWS. Examples of situations for which entry into this Condition isprohibited are emergent repair of discovered piping leaks and other componentfailures. For unplanned events or other events involving the NSWS, Condition Amust be entered. In addition, Note 1 states that entry into this Condition shall notbe allowed while Unit 2 is in MODE 1, Z 3, or 4. Entry into this Condition is onlyallowed while the LCO is not applicable to Unit 2. Note 2 requires immediateentry into Condition A of this LCO if one or more Unit I required NSWScomponents become inoperable while in this Condition and one NSWS trainremains OPERABLE. With one remaining OPERABLE NSWS train, the NSWS canstill perform its safety related function. However, with one inoperable NSWStrain, the NSWS cannot be assured of performing its safety related function in theevent of a single failure of another NSWS component. While the loss of anyNSWS component subject to the requirements of this LCO can result in the entry7 into Condition A, the most common example is the inoperability of an NSWSpump. This occurs during periodic testing of the emergency diesel generators.Inoperability of an emergency diesel generator renders its associated NSWSpump inoperable. Note 3 requires immediate entry into LCO 3.0.3 if one or moreUnit I required NSWS components become inoperable while in this Condition andno NSWS train remains OPERABLE. In this case, the NSWS cannot perform itssafety related function.Based on the above information, it is therefore unnecessary to add Notes similarto Notes 1 and 2 of Required Action A.1 into Required Action C.1. If any emergentsituation were to occur while Unit 1 is in Condition C, then Unit I would beimmediately required to enter LCO 3.7.8 Condition A or LCO 3.0.3, as applicable.(Note that if Unit I were in LCO 3.0.3 as a result of two inoperable NSWS trains,then Unit 1 would also be in LCO 3.7.8 Condition A for one inoperable NSWS train,since all Conditions and LCOs must be immediately entered when they becomeapplicable.) In this situation, Notes 1 and 2 of Required Action A.1 wouldimmediately become applicable.It should also be noted that entry into Condition C by itself does riot render anyemergency diesel generator or residual heat removal loop inoperable, since theNSWS is capable of providing flow through the normal flow paths with return toboth the normal Lake Wylie return and the Standby Nuclear Service Water Pond(SNSWP) return lines.7. For the case when NSWS Train A or Train B is out of service, the licenseeshould prove by calculation that NSWS pump 1A provides sufficient flow tosafety related components in Train 1A considering that the flow combines withthe flow from NSWS pumps 1 B and 2B in the discharge header and returns tothe SNSWP through the B loop (for Train A through 1 RN58B) or through the Aloop (for Train B through 1 RN63A).Duke Energy Response:A calculation has been performed that demonstrates that when the NSWS isaligned in the Single Discharge Header alignment and the Train A dischargeheader to the SNSWP is out of service, the NSWS Train 1A components willreceive sufficient flow. In this alignment, Train 1A NSWS discharge flowcombines with the Train 1B and Train 2B NSWS discharge flow and dischargesthrough the Train B header to the SNSWP.Likewise, a calculation has been performed that demonstrates that when theNSWS is aligned in the Single Discharge Header alignment and the Train Bdischarge header to the SNSWP is out of service, the NSWS Train 1 B componentswill receive sufficient flow. In this alignment, Train 1B NSWS discharge flowcombines with the Train 1A and Train 2A NSWS discharge flow and dischargesthrough the Train A header to theSNSWP.8 NSWS3.7.8ACTIONS (continued)CONDITION REQUIRED ACTION COMPLETION TIMEB. --------NOTES------1. Entry into thisCondition shall onlybe allowed for pre-planned activities asdescribed in theBases of thisSpecification.2. Immediately enterCondition A of thisLCO if one or moreNSWS componentsbecome inoperablewhile in thisCondition and oneNSWS train remainsOPERABLE.3. Immediately enterLCO 3.0.3 if one ormore NSWScomponents becomeinoperable while inthis Condition andno NSWS trainremainsOPERABLE.B.1Restore NSWS supplyheader to OPERABLEstatus.30 daysOne NSWS supplyheader inoperable dueto NSWS being alignedfor single supply headeroperation.(continued)Catawba Units 1 and 23.7.8-2Amendment Nos.

NSWS3.7.8ACTIONS (continued)CONDITION REQUIRED ACTION COMPLETION TIMEC. --------NOTES------1. Entry into thisCondition shall onlybe allowed for Unit 1and for pre-plannedactivities asdescribed in theBases of thisSpecification. Entryinto this Conditionshall not be allowedwhile Unit 2 is inMODE 1, 2, 3, or 4.2. Immediately enterCondition A of thisLCO if one or moreUnit 1 requiredNSWS componentsbecome inoperablewhile in thisCondition and oneNSWS train remainsOPERABLE.3. Immediately enterLCO 3.0.3 if one ormore Unit 1 requiredNSWS componentsbecome inoperablewhile in thisCondition and noNSWS train remainsOPERABLE.C.1 Restore NSWS train toOPERABLE status.14 daysOne NSWS traininoperable due toNSWS being aligned forsingle Auxiliary Buildingdischarge headeroperation.(continued)Catawba Units 1 and 23.7.8-3Amendment Nos.

NSWS3.7.8ACTIONS (continued)CONDITION REQUIRED ACTION COMPLETION TIMED. Required Action and D.1 Be in MODE 3. 13 hour1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />sassociated CompletionTime of Condition A, B, ANDor C not met.D.2 Be in MODE 5. :36 hoursSURVEILLANCE REQUIREMENTSSURVEILLANCE FREQUENCYSR 3.7.8.1 -----------------------NOTE ---------------Isolation of NSWS flow to individual components doesnot render the NSWS inoperable.Verify each NSWS manual, power operated, and In accordance withautomatic valve in the flow path servicing safety related the Surveillanceequipment, that is not locked, sealed, or otherwise Frequency Controlsecured in position, is in the correct position. ProgramSR 3.7.8.2 ---------------------NOTE ------------------Not required to be met for valves that are maintained inposition to support NSWS single supply or dischargeheader operation.Verify each NSWS automatic valve in the flow path that In accordance withis not locked, sealed, or otherwise secured in position, the Surveillanceactuates to the correct position on an actual or simulated Frequency Controlactuation signal. ProgramSR 3.7.8.3 Verify each NSWS pump starts automatically on an In accordance withactual or simulated actuation signal. the SurveillanceFrequency ControlProgramCatawba Units 1 and 23.7.8-4Amendment Nos.

NSWSB 3.7.8B 3.7 PLANT SYSTEMSB 3.7.8 Nuclear Service Water System (NSWS)BASESBACKGROUND The NSWS, including Lake Wylie and the Standby Nuclear ServiceWater Pond (SNSWP), provides a heat sink for the removal of processand operating heat from safety related components during a DesignBasis Accident (DBA) or transient. During normal operation, and anormal shutdown, the NSWS also provides this function for various safetyrelated and nonsafety related components. The safety related function iscovered by this LCO.The NSWS consists of two independent loops (A and B) of essentialequipment, each of which is shared between units. Each loop containstwo NSWS pumps, each of which is supplied from a separate emergencydiesel generator. Each set of two pumps supplies two trains (1A and 2A,or 1 B and 2B) of essential equipment through common discharge piping.While the pumps are unit designated, i.e., 1A, 1B, 2A, 2B, all pumpsreceive automatic start signals from a safety injection or blackout signalfrom either unit. Therefore, a pump designated to one unit will supplypost accident cooling to equipment in that loop on both units, provided itsassociated emergency diesel generator is available. For example, the 1ANSWS pump, supplied by emergency diesel 1A, will supply post accidentcooling to NSWS trains 1A and 2A.One NSWS loop containing two OPERABLE NSWS pumps has sufficientcapacity to supply post loss of coolant accident (LOCA) loads on one unitand shutdown and cooldown loads on the other unit. Thus, theOPERABILITY of two NSWS loops assures that no single failure willkeep the system from performing the required safety function.Additionally, one NSWS loop containing one OPERABLE NSWS pumphas sufficient capacity to maintain one unit indefinitely in MODE 5(commencing 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> following a trip from RTP) while supplying thepost LOCA loads of the other unit. Thus, after a unit has been placed inMODE 5, only one NSWS pump and its associated emergency dieselgenerator are required to be OPERABLE on each loop, in order for thesystem to be capable of performing its required safety function, includingsingle failure considerations.Additional information about the design and operation of the NSWS,along with a list of the components served, is presented in the UFSAR,Section 9.2.1 (Ref. 1). The principal safety related function of the NSWSis the removal of decay heat from the reactor via the CCW System.Catawba Units 1 and 2B 3.7.8-1Revision No. 5 NSWSB 3.7.8BASESAPPLICABLESAFETY ANALYSESThe design basis of the NSWS is for one NSWS train, in conjunctionwith the CCW System and a containment spray system, to remove coredecay heat following a design basis LOCA as discussed in the UFSAR,Section 6.2 (Ref. 2). This prevents the containment sump fluid fromincreasing in temperature during the recirculation phase following aLOCA and provides for a gradual reduction in the temperature of this fluidas it is supplied to the Reactor Coolant System by the ECCS pumps.The NSWS is designed to perform its function with a single failure of anyactive component, assuming the loss of offsite power.The NSWS, in conjunction with the CCW System, also cools the unitfrom residual heat removal (RHR), as discussed in the UFSAR,Section 5.4 (Ref. 3), from RHR entry conditions to MODE 5 during normaland post accident operations. The time required for this evolution is afunction of the number of CCW and RHR System trains that areoperating. Thirty six hours after a trip from RTP, one NSWS train issufficient to remove decay heat during subsequent operations inMODES 5 and 6. This assumes a maximum NSWS temperature, asimultaneous design basis event on the other unit, and the loss of offsitepower.The NSWS satisfies Criterion 3 of 10 CFR 50.36 (Ref. 4).LCOTwo NSWS trains are required to be OPERABLE to provide the requiredredundancy to ensure that the system functions to remove post accidentheat loads, assuming that the worst case single active failure occurscoincident with the loss of offsite power.While the NSWS is operating in the normal dual supply and dischargeheader alignment, an NSWS train is considered OPERABLE duringMODES 1, 2, 3, and 4 when:a. 1. Both NSWS pumps on the NSWS loop are OPERABLE; or2. One unit's NSWS pump is OPERABLE and one unit'sflowpath to the non essential header, AFW pumps, andContainment Spray heat exchangers are isolated (orequivalent flow restrictions); andb. The associated piping, valves, and instrumentation and controlsrequired to perform the safety related function are OPERABLE.Catawba Units 1 and 2B 3.7.8-2Revision No. 5 NSWSB 3.7.8BASESLCO (continued)The NSWS system is shared between the two units. The shared portionsof the system must be OPERABLE for each unit when that unit is in theMODE of Applicability. Additionally, both normal and emergency powerfor shared components must also be OPERABLE. If a shared NSWScomponent becomes inoperable, or normal or emergency power toshared components becomes inoperable, then the Required Actions ofthis LCO must be entered independently for each unit that is in theMODE of applicability of the LCO, except as noted in a.2 above foroperation in the normal dual supply header alignment. In this case,sufficient flow is available, however, this configuration results ininoperabilities within other required systems on one unit and theassociated Required Actions must be entered. Use of a NSWS pumpand associated diesel generator on a shutdown unit to support continuedoperation (> 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) of a unit with an inoperable NSWS pump isprohibited. A shutdown unit supplying its associated emergency powersource (1EMXG/2EMXH) cannot be credited for OPERABILITY ofcomponents supporting the operating unit.APPLICABILITY In MODES 1, 2, 3, and 4, the NSWS is a normally operating system thatis required to support the OPERABILITY of the equipment serviced bythe NSWS and required to be OPERABLE in these MODES.In MODES 5 and 6, the requirements of the NSWS are determined by thesystems it supports.ACTIONS A.1If one NSWS train is inoperable, action must be taken to restoreOPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In this Condition, the remainingOPERABLE NSWS train is adequate to perform the heat removalfunction. However, the overall reliability is reduced because a singlefailure in the OPERABLE NSWS train could result in loss of NSWSfunction. Due to the shared nature of the NSWS, both units are requiredto enter a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Action when a NSWS Train becomes inoperable oneither unit. Required Action A.1 is modified by two Notes. The first Noteindicates that the applicable Conditions and Required Actions ofLCO 3.8.1, "AC Sources-Operating," should be entered if an inoperableNSWS train results in an inoperable emergency diesel generator. Thesecond Note indicates that the applicable Conditions and RequiredActions of LCO 3.4.6, "RCS Loops-MODE 4," should be entered if aninoperable NSWS train results in an inoperable decay heat removal trainCatawba Units 1 and 2B 3.7.8-3Revision No. 5 NSWSB 3.7.8BASESACTIONS (continued)(RHR). An example of when these Notes should be applied is with bothunits' loop 'A' NSWS pumps inoperable, both units' 'A' emergency dieselgenerators and both units' 'A' RHR systems should be declaredinoperable and appropriate Actions entered. This is an exception toLCO 3.0.6 and ensures the proper actions are taken for thesecomponents. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the redundantcapabilities afforded by the OPERABLE train, and the low probability of aDBA occurring during this time period.B.1While the NSWS is operating in the single supply header alignment, oneof the supply headers is removed from service in support of plannedmaintenance or modification activities associated with the supply headerthat is taken out of service. In this configuration, each NSWS train isconsidered OPERABLE with the required NSWS flow to safety relatedequipment being fed through the remaining OPERABLE NSWS supplyheader. While the NSWS is operating in the single supply headeralignment, an NSWS train is considered OPERABLE during MODES 1, 2,3, and 4 when:a. The associated train related NSWS pumps are OPERABLE; andb. The associated piping (except for the supply header that is takenout of service), valves, and instrumentation and controls required toperform the safety related function are OPERABLE.If one NSWS supply header is inoperable due to the NSWS being alignedfor single supply header operation, the NSWS supply header must berestored to OPERABLE status within 30 days. Dual supply headeroperation is the normal alignment of the NSWS. The Completion Time of30 days is supported by probabilistic risk analysis. While in Condition B,the single supply header is adequate to perform the heat removalfunction for all required safety related equipment for both safety trains.Due to the shared nature of the NSWS, both units are required to enterthis Condition when the NSWS is aligned for single supply headeroperation. In order to prevent the potential for NSWS pump runout, thesingle NSWS pump flow balance alignment is prohibited while the NSWSis aligned for single supply header operation.Catawba Units 1 and 2B 3.7.8-4Revision No. 5 NSWSB 3.7.8BASESACTIONS (continued)Condition B is modified by three Notes. Note 1 states that entry into thisCondition shall only be allowed for pre-planned activities as described inthe Bases of this Specification. Condition B is only allowed to be enteredin support of planned maintenance or modification activities associatedwith the supply header that is taken out of service. An example of asituation for which entry into this Condition is allowed is refurbishment orinspection of a supply header. Entry into this Condition is not allowed inresponse to unplanned events or for other events involving the NSWS.Examples of situations for which entry into this Condition is prohibited areemergent repair of discovered piping leaks and other component failures.For unplanned events or other events involving the NSWS, Condition Amust be entered. Note 2 requires immediate entry into Condition A ofthis LCO if one or more NSWS components become inoperable while inthis Condition and one NSWS train remains OPERABLE. With oneremaining OPERABLE NSWS train, the NSWS can still perform its safetyrelated function. However, with one inoperable NSVVS train, the NSWScannot be assured of performing its safety related function in the event ofa single failure of another NSWS component. The most limiting singlefailure is the failure of an NSWS pit to automatically transfer from LakeWylie to the SNSWP during a seismic event. While the loss of anyNSWS component subject to the requirements of this LCO can result inthe entry into Condition A, the most common example is the inoperabilityof an NSWS pump. This occurs during periodic testing of the emergencydiesel generators. Inoperability of an emergency diesel generatorrenders its associated NSWS pump inoperable. Note 3 requiresimmediate entry into LCO 3.0.3 if one or more NSWS componentsbecome inoperable while in this Condition and no NSWS train remainsOPERABLE. In this case, the NSWS cannot perform its safety relatedfunction.C.1While the NSWS is operating in the single Auxiliary Building dischargeheader alignment, one of the Unit 2 Auxiliary Building discharge headersis removed from service in support of planned maintenance ormodification activities associated with the Auxiliary Building dischargeheader that is taken out of service. In this configuration, thecorresponding (train related) Unit 1 NSWS train is inoperable and therequired NSWS flow to safety related equipment is discharged throughthe remaining OPERABLE NSWS Auxiliary Building discharge header.When in the single Auxiliary Building discharge header alignment with theNSWS Train A discharge header inoperable, the NSWS piping betweenCatawba Units 1 and 2B 3.7.8-5Revision No. 5 NSWSB 3.7.8BASESACTIONS (continued)valves 1RNP19 and 1RN63A is isolated. Likewise, when in the singleAuxiliary Building discharge header alignment with the NSWS Train Bdischarge header inoperable, the NSWS piping between valves 1 RNP20and 1RN58B is isolated.Operation of the NSWS in the single supply header alignment and thesingle Auxiliary Building discharge header alignment at the same time isprohibited.If one NSWS train is inoperable due to the NSWS being aligned forsingle Auxiliary Building discharge header operation, the NSWS trainmust be restored to OPERABLE status within 14 days. Dual AuxiliaryBuilding discharge header operation is the normal alignment of theNSWS. The Completion Time of 14 days is supported by probabilisticrisk analysis. While in Condition C, the single Auxiliary Buildingdischarge header is adequate to perform the heat removal function for allrequired safety related equipment for its respective safety train. Due tothe design of the NSWS, only the operating unit is required to enter thisCondition when the NSWS is aligned for single Auxiliary Buildingdischarge header operation. Pre-planned activities requiring entry intothis Condition are only performed with Unit 2 in an outage (MODE 5, 6, ordefueled).Condition C is modified by three Notes. Note 1 states that entry into thisCondition shall only be allowed for Unit 1 and for pre-planned activities asdescribed in the Bases of this Specification. Condition C is only allowedto be entered in support of planned maintenance or modification activitiesassociated with the Auxiliary Building discharge header that is taken outof service. An example of a situation for which entry into this Condition isallowed is refurbishment or inspection of an Auxiliary Building dischargeheader. Entry into this Condition is not allowed in response to unplannedevents or for other events involving the NSWS. Examples of situationsfor which entry into this Condition is prohibited are emergent repair ofdiscovered piping leaks and other component failures. For unplannedevents or other events involving the NSWS, Condition A must be entered.In addition, Note 1 states that entry into this Condition shall not beallowed while Unit 2 is in MODE 1, 2, 3, or 4. Entry into this Condition isonly allowed while the LCO is not applicable to Unit 2. Note 2 requiresimmediate entry into Condition A of this LCO if one or more Unit 1required NSWS components become inoperable while in this Conditionand one NSWS train remains OPERABLE. With one remainingOPERABLE NSWS train, the NSWS can still perform its safety relatedfunction. However, with one inoperable NSWS train, the NSWS cannotbe assured of performing its safety related function in the event of aCatawba Units 1 and 2B 3.7.8-6Revision No. 5 NSWSB 3.7.8BASESACTIONS (continued)single failure of another NSWS component. While the loss of any NSWScomponent subject to the requirements of this LCO can result in the entryinto Condition A, the most common example is the inoperability of anNSWS pump. This occurs during periodic testing of the emergencydiesel generators. Inoperability of an emergency diesel generatorrenders its associated NSWS pump inoperable. Note 3 requiresimmediate entry into LCO 3.0.3 if one or more Unit 1 required NSWScomponents become inoperable while in this Condition and no NSWStrain remains OPERABLE. In this case, the NSWS cannot perform itssafety related function.D.1 and D.2If the NSWS train cannot be restored to OPERABLE status within theassociated Completion Time, or if the NSWS supply header cannot berestored to OPERABLE status within the associated Completion Time,the unit must be placed in a MODE in which the LCO does not apply. Toachieve this status, the unit must be placed in at least MODE 3 within6 hours and in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.The allowed Completion Times are reasonable, based on operatingexperience, to reach the required unit conditions from full powerconditions in an orderly manner and without challenging unit systems.SURVEILLANCE SR 3.7.8.1REQUIREMENTSThis SR is modified by a Note indicating that the isolation of the NSWScomponents or systems may render those components inoperable, butdoes not affect the OPERABILITY of the NSWS.Verifying the correct alignment for manual, power operated, andautomatic valves in the NSWS flow path provides assurance that theproper flow paths exist for NSWS operation. This SR does not apply tovalves that are locked, sealed, or otherwise secured in position, sincethey are verified to be in the correct position prior to being locked, sealed,or secured. This SR does not require any testing or valve manipulation;rather, it involves verification that those valves capable of beingmispositioned are in the correct position. This SR does not apply tovalves that cannot be inadvertently misaligned, such as check valves.The Surveillance Frequency is based on operating experience,equipment reliability, and plant risk and is controlled under theSurveillance Frequency Control Program.Catawba Units 1 and 2B 3.7.8-7Revision No. 5 NSWSB 3.7.8BASESSURVEILLANCE REQUIREMENTS (continued)SR 3.7.8.2This SR verifies proper automatic operation of the NSWS valves on anactual or simulated actuation signal. The signals that cause the actuationare from Safety Injection and Phase 'B' isolation. The NSWS is anormally operating system that cannot be fully actuated as part of normaltesting. This Surveillance is not required for valves that are locked,sealed, or otherwise secured in the required position under administrativecontrols. The Surveillance Frequency is based on operating experience,equipment reliability, and plant risk and is controlled under theSurveillance Frequency Control Program.This SR is modified by a Note that states that the SR is not required to bemet for valves that are maintained in position to support NSWS singlesupply or discharge header operation. When the NSWS is placed in thisalignment, certain automatic valves in the system are maintained inposition and will not automatically reposition in response to an actuationsignal while the NSWS is in this alignment.SR 3.7.8.3This SR verifies proper automatic operation of the NSWS pumps on anactual or simulated actuation signal. The signals that cause the actuationare from Safety Injection and Loss of Offsite Power. The NSWS is anormally operating system that cannot be fully actuated as part of normaltesting during normal operation. The Surveillance Frequency is based onoperating experience, equipment reliability, and plant risk and iscontrolled under the Surveillance Frequency Control Program.REFERENCES 1. UFSAR, Section 9.2.2. UFSAR, Section 6.2.3. UFSAR, Section 5.4.4. 10 CFR 50.36, Technical Specifications, (c)(2)(ii).Catawba Units 1 and 2B 3.7.8-8Revision No. 5