ML17244A374

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Forwards Review of Safety Actuation Circuits W/Manual Override.Reset Operation Does Not Prevent Equipment from Operating,Which Is Necessary to Mitigate a Postulated Accident
ML17244A374
Person / Time
Site: Ginna Constellation icon.png
Issue date: 02/16/1979
From: WHITE L D
ROCHESTER GAS & ELECTRIC CORP.
To: ZIEMANN D L
Office of Nuclear Reactor Regulation
References
TASK-06-04, TASK-6-4, TASK-RR NUDOCS 7902210226
Download: ML17244A374 (8)


Text

NOTES.tBEGULAT(g INFORMATION DISTBIBUTIONyYSTEM (RIDE>ACCESSION NBR-7902210226 DOC.DATEi 79/02/16NOTARIZED~

NODOCKET0FACILt50-244 RobertEmmetGinnaNuclear.PowerPlant,UnitI,Roches05000244AUTH.NAMEAUTHORAFFILIATION WHITE,L.D.

Rochester Gas8,ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION ZIEMANN,.D.L.

,Operating Rector+Branch2SUBJECTSForwardsreviewofsafetyactuation..circuits w/manualoverride.

Concludes resetoperation doesnotpreventequipment from.operating

.whi'chisnecessary tonitigateapostulated accident.

eDISTBIBUTI(>N CODEFAOOISCOPIESRECEIVED(LTR MENCL~SIZE<~TITLE(GENERALDISTRIBUTION FOBAFTERISSUANCEOFOPERATING LIC~((-~ll~~a<o45RFCIPIENTIDCODE/NAME ACTION-05BCA@6+~INTERNAL-t 03.EGFILE1.215KORE,PERF BR.I7ENGRBR019PLANT.SYSBR21EFLTTRT.SYSEXTERNAL.i 03LPDR23ACRSCOPIESLTTRENCL77.II22.I.I,I~1II.I,II1616RECAPIENTID'ODE/NAME 02NRCPDRI'((ITA/ED()16AD5YS/PROJ18REACSFTYBR20EEB22BRINKMAN04NSICCOPIESLTTRENCL.III.III.II.II.II.II~((UfgQt6Ad~sgagric~TOTALNUMBER.OFCOPIESREQUIRED'TTR 38ENCL38 IE1IIr,rr

~Pr~*February16,1979DirectorofNuclearReactorRegulation Attention:

Mr.DennisL.Ziemann,ChiefOperating ReactorBranchNo.2U.S.NuclearRegulatory Commission Washington, D.C.20555

Subject:

ReviewofSafetyActuation CircuitswithOverrides R.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Ziemann:

4YourletterdatedNovember29,1978requested restrictions beplacedoncontainment purgingduringnormaloperation andthatareviewofallsafetyactuation signalcircuitswhichincorporate manualoverridefeaturesbemade.TheRochester GasandElectricCorporation (RGB)letterdatedJanuary2,1979transmitted theRG6Ecommitments onpurgingduringnormaloperation andstatedthattherequiredreviewofoverridefeatureswouldbecompleted bymidFebruary1979.Thepurposeofthisletteristotransmittheresultsofthatreview.Detailsofthereviewarepresented inAppendixA.Thereviewofallsafetyactuation signalcircuitswhichincorporate amanualoverridefeatureindicates thatactuating aparticular override(reset)doesnotcausethebypassofothersafetyactuation signals.Theresetswitchesdescribed inAppendixAarepushbuttonswitcheslocatedonthecontrolboardwithnophysicalrestraints.

Inallcaseswherethesafetyactuation signalisgenerated automatically andtheresetswitchisactuated, thesafetyactu-ationsignalwillbeinhibited untilalllogicpathsforauto-matically generating thesafetyactuation signalhaveopened.Oncealllogicpathsopen,theparticular safetyactuation signalresetrelaysde-energize andre-establish theabilitytoauto-matically generatethesafetyactuation signal.Sincetheresetremainsactuatedonlyiftheinputsignalscausingtheautomatic safetyactuation signalpersistandtheseinputsignalsareannunciated, noseparateannunciation fortheresetactuation isnecessary.

Theoperatorhassufficient information todeducea~certainsystemisintheresetmode.p0v80zzaoww4 e,'g~(g',

ROCHFST=R GwSAiVOL=CTR)CCORP.February16,1979TcMr.D.L.Ziemann,ChiefryEET,VO1Znnocasedoesactuation ofaparticular resetswitchpreventtheoperatorfrommanuallyoperating theequipment fromthecontrolboard.Therefore, operation ofaresetdoesnotpreventequipment fromoperating whichisnecessary tomitigatetheconsequences ofapostulated accident.

Verytrulyyours,~~+L.D.White,Jr.LDW:npAttachment AppendixAReviewofSafetyActuation SignalCircuitsIncorporating manualOverrides Thefollowing summaxizes theresultsofareviewofsafetyactu-ationsignalcircuitswhichincorporate amanualoverridefeature.Thepurposeofthereviewistoensurethatoverriding ofonesafetyactuation signaldoesnotalsocausethebypassofanyothersafetyactuation signals:SAFETYINJECTION CIRCUIT:Thiscircuithasaresetswitchwhichgivestheoperatorthemeansofresetting safetyinjection one-minuteorlongerafterinitiation.

Actuation ofthereset.swatchinitselfdoesnotchangethestateofanyequipment, butpermitstheoperatortoplacetheequipment affectedbysafetyinjection tothepositiondesired.Ifsafetyin]ection iscausedbyautomatic actuation, andtheresetswitchisactuated, automatic safetyingection willbeinhibited untilalllogicpathsforautomatic safetyinjection haveopened.Oncealllogicpathsopen,thesafetyinjection resetrelaysde-energize andre-establishes automatic safetyinjection capabilities.

Manualsafetyinjection initiation isavailable atalltimes.Thereisnoannunciation ofthesafetyxngection circuitbeingintheresetmode.Thepurposeoftheresetswitchonthesafetyinjection systemistoallowequipment toberealigned fortherecirculation phaseofapostulated LOCA.2.CONTAINMENT VENTILATION ISOLATION CIRCUIT:Thiscircuithasaresetswitchwhichgivestheopexatorthemeansofresetting containment ventilation isolation.

Oncetheresetswitchhasbeenactuated, most'oftneequipment.

willautomatically returntothestateselectedpriortotheisolation signal.Ifcontainment ventilation isolation wascausedautomatically, eitherbysafetyinjection orhighradiation alarmoncontainment gasand/orparticulate

monitors, andthiscondition continues toexist:afterthexesetswitchhasbeenactuated, thencontainment ventilation isolation cannotbeachievedautomatically orbythemanualisolation switchesuntilth'islogicclears.Oncetheautomatic logicclears,thecontainment ventilation isolation resetrelaysde-energize andre-establishes automatic ormanualisolation capabilities.

Manualoperation ofthevalvesfromthecontrolboardisavailable atalltimes.Thereisnoannunciation oftheautomatic containment ventilation isolation systembeingintheresetmode.IJThepurposeoftheresetswitchonthecontainment venti-lationisolation systemistoallowpurgingofcontainment inordertolimitpotential hydrogenconcentration buildupfollowing apostulated LOCAwhenhighcontainment activityandsafetyinjection signalscouldbepresent.3.CONTAINMENT ISOLATION CIRCUIT:Thiscircuithasaresetswitchwhichgivestheoperatorthemeansofresetting containment

.isolation.

Oncetheresetswitchhasbeenactuated, someequipment willreturn,automatically tothepositionselectedpriortotheiso-lationsignal.Ifcontainment isolation wascausedautomatically byanautomatic safetyinjection signal,andcontainment iso-lationresetswitchisactuatedwithoutresetting safetyinjection, containment isolation cannotbeobtainedbythemanualcontainment isolation switchesuntilsafetyinjec-tionisreset.Actuation oftheresetpermitstheoperatortoplacethevalvesaffectedbythecontainment isolation signalintheposition~desired.

Thiscapability isnecessary sothattheoperatorhasflexibility indealingwithpostaccidentconditions withincontainment.

Thereisnoannunciat'ion oftheautomatic containment isolation beingintheresetmode.4.CONTAINMENT SPRAYCIRCUIT:Thiscircuithasaresetswitchwhichgivestheoperatorthemeansofresetting containment spray.Oncetheresetswitchhasbeenactuatedthesprayadditivetankdischarge valveswillreturnautomatically tothepositioncalledforbythecontroller priortothecontainment spraysignal.Thecontainment spraypumpsandtheirdischarge valveswouldrequireoperatoractiontochangestate.Ifcontainment spraywascausedautomatically bythehighcontainment pressurelogic,andthislogiccontinues toexistafterreset,containment spraycannotbeinitiated bythemanualsprayswitches.

Oncethehighpressurelogichascleared,thecontainment sprayresetrelaysde-energize andre-establishes automatic ormanualcontain-mentspraycapabilities.

Actuation oftheresetpermitstheoperatortoplacethevalvesandpumpsaffectedbythecontainment spraysignalinthestatedesired.Thiscapability isnecessary sothattheoperatorhasflexibility indealingwithpostaccidentconditions withincontainment.

Thereisnoannunciation oftheautomatic containment spraysystembeingintheresetmode.5.FEEDNATER ISOLATION RESET:Thiscircuithasaresetswitchwhichgivestheoperatorthemeansofresetting theisolation signaltothefeed-waterbypassvalvesonly.Themainfeedwater valveswillremaincloseduntiltheisolation logicclears,andthentheyautomatically assumethepositionrequested bytheircontrolcircuit.Iffeedwater isolation iscausedbyhighsteamgenerator levellogic,andthiscondition stillexistsaftertheresetswitchisactuated,-a safetyinjection sign'alwouldnotcauseanisolation tothatparticular feedwater bypassvalve.Itshouldbenotedthatasafetyinjection signalalsocausesthemainfeedwater pumpstobetripped,therefore, closingthefeedwater bypassvalvesonasafetyinjection signalisredundant.

Thereisnoannunciation oftheautomatic feedwater iso-lationsystembeingintheresetmode.6NUCLEARINSTRUMENTATION SYSTEMDEFEAT~BYPASSgANDBLOCKSWITCHES:

~Thissystemhasseveralswitcheswhichareusedforthefollowing purposes:

(a)DefeatSwitches-Defeatsapermissive whichrein-statesatriplogic.(b)BypassSwitches-Bypassesatriporrunbackfunctionforcalibration ormaintenance purposes.

Protection isstillprovidedbyredundant channelorchannels.

(c)BlockSwitches-Blockstripsgenerated bysource,.intermediate, andpowerrangechannels.

Theseswitchesareactuatedaspermissive setpoints arereachedtopermittakingreactorcriticalandupinpower.Theseblocksautomatically resetaspowerisdecreased belowitsparticular setpoint.

Alltheaboveswitchesifactuated, areindicated byoneormoreofthefollowing:

statuslight,alarmonthecomputer, oractuateanannunciator.

7.INSTRUMENT ANDCONTROLDEFEATSWITCHES:

Thefollowing switchesandtheircircuitswerereviewedtoinsurethattheyareonlyperforming theirintendedfunction, andnoothersafetyfunctions arebeingbypassed.

The-purposefortheseswitchesistobeabletoswitchcontrolfromonesensorlooptoanotherfortesting,calibration andmaintenance purposes.

Inallcases,reactortripandsafetyinjection signalsaregenerated priortodefeatswitches, andarenotaffectedbyswitchposition.

(a)P/429APressurizer PressureSelectorSwitcn-Usedtoselecttwoofthefourpressurizer pressurechannelsforcontrolling pressurizer heaters,sprays,andpowerreliefvalvePCV-430.(b)L/428APressurizer LevelSelectorSwitch-Vsedtosele'cttwoofthethreepressurizer levelchannelsforcontrolling chargingpumpspeed,letdowniso-lation,andpressurizer heaters.(c)T/405EandT/405FDeltaTDefeatSwitches-Vsedtodefeatachannelfromtheovertemperature andoverpowerturbinerunbackcircuit,andtoremoveachannelDeltaTsignalfromtheinputofthesummerforgenerating theaverageDeltaTsignalortheRodInsertion LimitCircuit.(d)T/401AandT/401BTavgDefeatSwitches-UsedtodefeataTavgchannelfromtheinputtotheaverageTavgsummerwhichisusedforfulllengthrodcontrol,condenser steamdump,andpressurizer levelsetpoint.