ML21126A315

Proposed License Amendment Request to Battery Surveillance Requirements - Response to Request for Additional Information

ML21126A315
Person / Time
Site:	North Anna
Issue date:	05/06/2021
From:	Mark D. Sartain Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
21-137
Download: ML21126A315 (8)

Text

I VIRGINIAELECTRIC AND POWERCOMPANY RICHMOND,VIRGINIA 23261 I

May6,2021 ATTN:

Document Control Desk Serial No.:

21-137 U.S.Nuclear Regulatory Commission NRA/ENC:

RO Washington, DC20555-0001 Docket Nos.:50-338

/

50-339 I

I License Nos.:NPF-4 NPF-7 I

V NORTHANNAPOWERSTATION UNITS 1AND2 I

II Byletter dated December 17,2020(Agencywide Documents AccessandManagement System(ADAMS)

Accession No.ML20352A394),

Virginia Electric andPowerCompany (Dominion Energy Virginia) requested changes tothe Technical Specifications (TS) for i

North AnnaPowerStation (NAPS)

Units 1and2.Specifically,the proposed amendment I

revises NAPSTS 3.8.4, "Electrical PowerSystems, DC Sources Operating,"

Surveillance Requirements (SRs) 3.8.4.2 and3.8.4.5 byadding newacceptance criteria foreachsafety-related battery thatspecify a total connection resistance value as f

established byNorth Annacalculations.

j Theinter-cell connection resistance value of1.5E-4 Ohmcurrently specified inTS 3.8.4 i

isnon-conservative

ifall, oraconsiderable

number, oftheconnections are postulated to E

beattheTSlimit

value, since theacceptable total battery connection resistance value wouldbeexceeded.

Thenewacceptance criteria will confirm thatthetotal battery

/

connection resistance iswithin pre-established limits andensures that thebatteries will perform their specified safety function bymaintaining required battery terminal voltage under designed loadconditions.

I Byemail datedMarch26,2021,NRCstaff indicated thatadditional information was I

necessary tocomplete their review oftherequested changes.

TheNRCrequested a

l response totheir request foradditional information (RAl) byMay7,2021.TheEnterprise Project Identifier (EPID) referenced forthis request isL-2020-LLA-0275.

Dominion Energy Virginia's response totheNRCsRAIiscontained intheEnclosure to this letter.

g i

Serial No.:

21-137 Docket Nos.:

50-338/339 Page2of3 Please contact Erica N.Combsat804-273-3386 ifyouhaveanyquestions regarding this submittal.

Sincerely,

-.a MarkD.Sartain VicePresident

- Nuclear Engineering & Fleet Support COMMONWEALTH OFVIRGINIA

))

COUNTYOFHENRICO

)

Theforegoing document wasacknowledged before rne,inand for theCounty andCommonwealth aforesaid, today byMr.MarkD.Sartain, whoisVicePresident Nuclear Engineering andFleet

Support, ofVirginia Electric andPowerCompany.

Hehasaffirmed before methat he isduly authorizedtoexecute andfile theforegoing document inbehalf ofthat

company, andthat thestatements inthedocument are truetothebestofhisknowledge andbelief.

Acknowledged before methisfo dayof

, 2021.

MyCommission Expires:

0Na PDu i

Commonwealth ofVirginia Reg.# 7518653 MyCommission ExpiresDecember 31,2023 N tary P

ic

Enclosure:

,Response toNRCRequest forAdditional Information Commitments madebythis letter:

None

References:

1 Letter fromDominion Energy Virginia toNRC,"North AnnaPowerStation Units 1and 2, Proposed License AmendmentRequesttoChangeBattery Surveillance Requirements,"

dated December 17,2020.[ADAMS Accession No.ML20352A394)

Serial No.:

21-137 Docket Nos.:

50-338/339 Page3of3 cc:

Regional Administrator, Region II U. S.Nuclear Regulatory Commission Marquis OneTower 245Peachtree CenterAvenue, NE,Suite 1200 Atlanta,Georgia 30303-1257 Mr.G.E.Miller Senior Project Manager

- North AnnaPowerStation U.S.Nuclear Regulatory Commission MailStop09E-3 OneWhiteFlint North 11555Rockville Pike Rockville, Maryland 20852-2738 Mr.Marcus Harris OldDominion Electric Cooperative Innsbrook Corporate Center 4201Dominion Boulevard, Suite 300 GlenAllen, Virginia 23060 NRCSenior Resident Inspector North AnnaPowerStation

Serial No.:21-137 Docket Nos.:

50-338/339 ENCLOSURE Virginia Electric andPowerCompany (Dominion Energy Virginia)

NorthAnnaPowerStation Unit 1andUnit 2

Serial No.:

21-137 Docket Nos.:

50-338/339 Enclosure Page1of4

RESPONSE

TONRCREQUEST FORADDITIONAL INFORMATION REGARDING PROPOSED LICENSEAMENDMENTREQUEST TO CHANGE BATTERY SURVEILLANCE REQUIREMENTS Byletter dated December 17, 2020(Agencywide Documents Access andManagement System(ADAMS)

Accession No. ML ML20352A394),

Virginia Electric andPower Company(Dominion EnergyVirginia) requested changes totheTechnical Specifications (TS) forNorth AnnaPower Station (NAPS) Units 1and2.Specifically, theproposed amendmentrevises NAPSTS 3.8.4, "Electrical PowerSystems, DC Sources Operating,"

Surveillance Requirements (SRs) 3.8.4.2and3.8.4.5 byadding new acceptance criteria foreachsafety-related battery thatspecify a total connection resistance value asestablished byNorth Anna calculations.

Theinter-cell connection resistance value of1.5E-4 Ohm specifiedinTS3.8.4 isnon-conservative

ifall, oraconsiderable

number, oftheconnections arepostulated tobeat theTSlimit

value, since theacceptable total battery connection resistance valuewould beexceeded.

Thenewacceptance criteria will confirm that the totalbattery connection resistance iswithin pre-established limits andensures that the batteries will perform their specified safety function bymaintaining required battery terminalvoltage underdesigned loadconditions.

InaMarch26,2021e-mail fromMr.EdMiller (NRC Senior Project Manager) toMs.Erica Combs(Dominion EnergyVirginia Corporate Licensing),

theNRC technical staff requested additional information regarding theproposed changes byMay7,2021.

The Enterprise Project Identifier (EPID) referenced forthis request isL-2020-LLA-0275.

Dominion's response totheNRCrequest foradditional information (RAI) isprovided below.

RAl

- Question No.1 W:

Theregulations at10CFR50.36, "Technical specifications,"

establish therequirements related tothecontent oftheTS.Pursuant to10CFR50.36(c),

TSarerequired toinclude items infive specific categories related tostation operation:

(1)

Safety

limits, limiting safety system

settings, andlimiting control

settings, (2)

Limiting conditions foroperation (LCOs),

Serial No.:21-137 Docket Nos.:

50-338/339 Enclosure Page2of4 (3) Surveillance requirements (SRs),

(4)Design features; and (5)

Administrative controls.

Theproposed changes inthis LARrelate totheSRcategory.

10CFRPart 50.36(c)(3),

"Surveillance requirements,"requires surveillance relating to

test, calibration, orinspection toassurethatthenecessary quality ofsystems and components ismaintained, that facility operationwill bewithin safety

limits, andthat the limiting conditions foroperationwill bemet.

E519115185L.

IntheLAR,Section 3.2,Technical Analysis, the licensee states:

Alorth Annavoltage profile calculations for the Class 1Ebatteries provide a

basis forthemaximumallowable total connection resistance values(to include theinter-cell, inter-jar, andcable termination connectors) that would ensure proper operation ofthe125VDCVital Busin Design Basis Accident andSBO[station blackout) scenarios.

Theinter-rack and inter-tier cable resistance isnotincluded within thebasis oftotal connection resistance values.

Theperiodic tests measure fromthecell post to thecable termination forthecable termination connectors.

Theinter-rack and inter-tier cables areseparately included inthecalculation analysis, and any configuration changethatwouldimpact thesecables would require an update totheanalysis.

Please provide asummary ofassumptions, design basis andmargins consideredfor total circuit resistances including battery internal resistance, battery system connection resistance, external conductor andconductor connection resistances.

Besponse:

Calculations EE-0857, "NAPSStation Battery 1-Ill Voltage Profile Calculation" andEE-0858,"NAPSStation Battery 1-ll Voltage Profile Calculation,"

provide thebasis forthe total Intercell Connection Resistance (ICR) ofallNorth Anna125VDCVital BusStation Batteries.

Analyses inbothcalculations wereperformed using theElectrical Transient Analyzer Program(ETAP) software.

TheEnersys/Exide 2GN-23stationary batteries wereoriginally installed underDesign Change DC85-29 andconsist of60cells residing in30jars secured tofourbattery racks.

Serial No.:21-137 Docket Nos.:

50-338/339 Enclosure Page3of4 Calculation EE-0857, Revision 0provides anallowable maximumICRof2,502micro-Ohmsbased ontheresults ofETAPvoltage dropanalysis forthe125VDCdistribution system ofthe 1-Ill 125VDCVital Bus.Thisanalysis isconsidered bounding forbatteries 1-I, 2-I, and2-Ill based onbattery dutycycle loading (amp-hours removed) andcontrol circuit lengths.

Calculation EE-0858,Revision 0,provides anallowable maximumICRof902micro-Ohmsbasedontheresults ofETAP voltage dropanalysis forthe125VDCdistribution systemofthe1-ll 125VDC Vital Bus.AddendumG tothis calculation provides an allowable maximumICRof1,502 micro-Ohms basedontheresults ofETAPvoltage drop analysis forthe2-II 125VDCVital Bus.

Theanalysis ofthe2-II 125VDCVital Busis considered bounding forbatteries 1-IV and 2-IVbasedonbattery duty cycle loading.

A value of8.5micro-Ohms forinter-jarconnectors and9.5micro-Ohms forinter-cell connectors wasassumed present inthe manufacturer suppliedperformance databased onmanufacturer dataanda review ofstation battery resistance readings.

Perthe manufacturer,

Enersys, sixtoeight cells areconnected inseries toderive discharge curves forendcell voltage.

Therefore theimpact ofconnection plates isincluded inthe datasupplied.

Thevalues assumed werebasedonanaverage ofmeasured resistances fromallstation batteries andcompared toaverage resistance readings supplied by Enersys.

Thevalues assumed wereconservatively lower than the values supplied by Enersys.

Theresistance ofconnector endplates wasincluded as part oftheoverall battery systemconnection resistance andwasnotincluded aspart of the assumed inter-cell andinter-jar connection resistance.

Overall analyzed battery system connection plate resistance doesnot include the effects ofinstalled battery connector

cables, onlyconnected inter-cell, inter-jar,and end connector plates.

Theeffects ofcables areconsidered asa separate elementof the North Anna125VDCbattery ETAPmodel(s).

During performance ofperiodic teststhat measurebattery resistance, theconnection cablesarenotincluded infield measurements.

Forcells attheendofeachrack, measurements aretaken fromthe battery posttothebolted lugconnecting thebattery cable.

Thetotal sumofinter-cell, inter-jar, andendconnector plate resistance iscompared toavalue boundbytheanalysis performed inCalculations EE-0857 andEE-0858.

Cabletemperatures wereassumedtobeoperating ata maximumrating of750Cto conservatively increase theresistance ofall cables.

Forcables within theNorth Anna battery rooms,thehighest expected roomtemperature is29.40C, allowing thecables 45.60C oftemperature rise during operation.

Thiswasconsidered conservative when comparing theevaluated 750Campacity ofthe250MCMAluminum cables that connect

Serial No.:

21-137 Docket Nos.:

50-338/339 Enclosure Page4of4 thebattery bank totheir respective distribution panel tothehighest continuous current producedin the ETAPmodel(s).

Battery cables are maintained asscheduled cables withpull ticket lengths referenced via Dominion's Plant Data Management System(PDMS) forNorth Anna.Each125VDC battery iscomposed of 4racks forall 60cells.

Scheduled inter-rack cables connect cell 12tocell 13andcell48 to cell49.Anunscheduled inter-tier cable connects cell 30to cell 31.Cell 31resides on the rackdirectly belowcell 30andisconnected bya setof fourparallel 2/0Copper cables supplied bythemanufacturer, withtheexception of Battery 1-III, whichhasfour parallel 4/0Aluminum conductors asprovided fromthe manufacturer during theoriginalinstallation ofthe2GN-23batteries.

Thebattery analyzed inCalculation EE-0857 includes theuseofthe4/0Aluminum

cables, which boundstheuseof2/0Copper onall other batteries.

Battery Internal Resistance isapart ofthe included ETAP battery library fortheGNseries ofbatteries.

Itseffects arepresent inthewayETAP calculates terminal voltage based onapplication ofIEEE485AnnexCtomanufacturer performance data.

Margin foroverall battery connection resistance isnotincluded intheanalyses performed inCalculations EE-0857 andEE-0858.

Instead, a small margin loadisincluded in Calculation EE-0857 toallow forincreases toDCpowered loads over timeandinclude a

theimpacts ofthepotential increases inloadonvoltage drop.

Calculation EE-0858 credits asmall margin loadforthe2-II, 1-IV, and2-IV125VDCVital Bus Distribution Systems butdoesnotinclude anyfor1-II duetothevoltage analysisresults during1-ll i

Station Battery's dutycycle.

Themargin loads aretracked byCorporate Electrical/I&C Analysis inconjunction withtheNorth AnnaStation Electrical LoadList andany required g

calculation updates.

TheETAPbattery modelanalyzes thetotal connection plate resistance inseries with the battery cables toinclude their effects onvoltage dropwithin theNorthAnna125VDC l

battery modelbetween themodeled battery source andthemaindistribution panel.

The maximumallowable resistance fromthecalculations hasbeenusedasthebasis forthis d

License Amendment Request.

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