Information Notice 2000-20, Potential Loss of Redundant Safety Related Equipment Due to Lack of a High-Energy Line Break Barriers: Difference between revisions
StriderTol (talk | contribs) Created page by program invented by StriderTol |
StriderTol (talk | contribs) Created page by program invented by StriderTol |
||
| Line 39: | Line 39: | ||
1.0x10-6/year.TwoofthesefourissuesinvolvedpostulatedHELBscenariosthatmayleadtofailureofredundantsafety-relatedsystems(seeLicenseeEventReports(LERs)316/98-005 and315/99-026fordetails).Withinthesetwoissuestherearethreescenariosthataredescribedbelow: | 1.0x10-6/year.TwoofthesefourissuesinvolvedpostulatedHELBscenariosthatmayleadtofailureofredundantsafety-relatedsystems(seeLicenseeEventReports(LERs)316/98-005 and315/99-026fordetails).Withinthesetwoissuestherearethreescenariosthataredescribedbelow: | ||
ÿAbreakinaUnit2mainsteamlineormainfeedwaterlinecoulddegradetheabilityofthecomponentcoolingwater(CCW)pumpsofbothunitstoperformtheirfunction.All | ÿAbreakinaUnit2mainsteamlineormainfeedwaterlinecoulddegradetheabilityofthecomponentcoolingwater(CCW)pumpsofbothunitstoperformtheirfunction.All | ||
| Line 57: | Line 58: | ||
Therefore,bothtrainsofsafety-related600Vbusesmayfailonexposuretothehigh | Therefore,bothtrainsofsafety-related600Vbusesmayfailonexposuretothehigh | ||
humidityandhightemperaturesofaHELB.ÿAHELBintheturbinebuildingcoulddegradetheabilityofallthreeauxiliaryfeedwater(AFW)pumps.Thedoortotheturbine-drivenAFWpumpisnormallyopenandmaynot | humidityandhightemperaturesofaHELB. | ||
ÿAHELBintheturbinebuildingcoulddegradetheabilityofallthreeauxiliaryfeedwater(AFW)pumps.Thedoortotheturbine-drivenAFWpumpisnormallyopenandmaynot | |||
closeintheeventofaHELB.Thetwomotor-drivenAFWpumpsareinroomswhose | closeintheeventofaHELB.Thetwomotor-drivenAFWpumpsareinroomswhose | ||
| Line 65: | Line 68: | ||
environment.Therefore,allAFWpumpsmayfailonexposuretothehighhumidityand | environment.Therefore,allAFWpumpsmayfailonexposuretothehighhumidityand | ||
hightemperaturesofaHELBintheturbinebuilding.DiscussionConditionsconducivetoarisk-significantconfiguration:Fourconditionsmustcoexisttoproducearisk-significantconfigurationlikethatatCook.Thesefourconditionsare(1)lackofaHELBbarrierbetweentheredundanttrainsofasystemthatis | hightemperaturesofaHELBintheturbinebuilding. | ||
DiscussionConditionsconducivetoarisk-significantconfiguration | |||
:Fourconditionsmustcoexisttoproducearisk-significantconfigurationlikethatatCook.Thesefourconditionsare(1)lackofaHELBbarrierbetweentheredundanttrainsofasystemthatis | |||
neededtomitigateaccidents,(2)thelackofenvironmentalqualificationfortheredundant | neededtomitigateaccidents,(2)thelackofenvironmentalqualificationfortheredundant | ||
| Line 116: | Line 123: | ||
documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's | documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's | ||
PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted | PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html | ||
.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted | |||
below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation | below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation | ||
| Line 138: | Line 147: | ||
documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's | documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's | ||
PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted | PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html | ||
.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted | |||
below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation | below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation | ||
| Line 151: | Line 162: | ||
CP=ConstructionPermitAttachmentIN2000-20 | CP=ConstructionPermitAttachmentIN2000-20 | ||
NoticeNo. | ===Page1of1LISTOFRECENTLYISSUEDNRCINFORMATIONNOTICES=== | ||
_____________________________________________________________________________________InformationDateof | |||
===NoticeNo.SubjectIssuanceIssuedto=== | |||
______________________________________________________________________________________2000-19ImplementationofHumanUseResearchProtocolsInvolving | |||
===U.S.NuclearRegulatory=== | ===U.S.NuclearRegulatory=== | ||
| Line 184: | Line 198: | ||
reactorvessel2000-16PotentialHazardsDuetoVolatilizationofRadionuclides10/5/2000AllNRClicenseesthatprocessunsealedbyproductmaterial2000-15RecentEventsResultinginWholeBodyExposures | reactorvessel2000-16PotentialHazardsDuetoVolatilizationofRadionuclides10/5/2000AllNRClicenseesthatprocessunsealedbyproductmaterial2000-15RecentEventsResultinginWholeBodyExposures | ||
ExceedingRegulatoryLimits9/29/2000Allradiographylicensees2000-14Non-VitalBusFaultLeadstoFireandLossofOffsitePower9/27/2000AllholdersofOLfornuclearpowerreactors2000- | ExceedingRegulatoryLimits9/29/2000Allradiographylicensees2000-14Non-VitalBusFaultLeadstoFireandLossofOffsitePower9/27/2000AllholdersofOLfornuclearpowerreactors2000-13ReviewofRefuelingOutage | ||
Risk9/27/2000AllholdersofOLfornuclearpowerreactors2000-12PotentialDegradationofFirefighterPrimaryProtective | |||
Garments9/21/2000Allholdersoflicensesfornuclearpower,research,andtest | Garments9/21/2000Allholdersoflicensesfornuclearpower,research,andtest | ||
reactorsandfuelcyclefacilities | reactorsandfuelcyclefacilities}} | ||
}} | |||
{{Information notice-Nav}} | {{Information notice-Nav}} | ||
Revision as of 16:12, 31 August 2018
| ML003760571 | |
| Person / Time | |
|---|---|
| Issue date: | 12/11/2000 |
| From: | Marsh L B Operational Experience and Non-Power Reactors Branch |
| To: | |
| References | |
| IN-00-020 | |
| Download: ML003760571 (5) | |
UNITEDSTATESNUCLEARREGULATORYCOMMISSIONOFFICEOFNUCLEARREACTORREGULATIONWASHINGTON,D.C.20555December11,2000NRCINFORMATIONNOTICE2000-20:POTENTIALLOSSOFREDUNDANTSAFETY-RELATEDEQUIPMENTBECAUSEOFTHELACK
OFHIGH-ENERGYLINEBREAKBARRIERS
Addressees
Allholdersofoperatinglicensesorconstructionpermitsfornuclearpowerreactors.
Purpose
TheU.S.NuclearRegulatoryCommission(NRC)isissuingthisinformationnoticetoalertaddresseestothediscoveryofseveralhigh-energylinebreak(HELB)concernsabout
redundantsafety-relatedequipmentatD.C.CookNuclearPlant,Units1and2.Afailureof
redundantsafety-relatedequipmentmayresultinrisk-significantconfigurations.Itisexpected
thattherecipientswillreviewtheinformationforapplicabilitytotheirfacilitiesandconsider
correctiveactions,asappropriate.However,suggestionscontainedinthisinformationnotice
arenotNRCrequirements;therefore,nospecificactionorwrittenresponseisrequired.BackgroundAsaresultofthenumeroussafetyissuesidentifiedatCook1and2sinceAugust1997,theNRCanalyzedtherisksignificanceofCookissuesusingtheAccidentSequencePrecursor
(ASP)programmethodology.Ofthe141issuesanalyzed,fourwerefoundtobeaccident
sequenceprecursorssincetheirconditionalcoredamagefrequenciesweregreaterthan
1.0x10-6/year.TwoofthesefourissuesinvolvedpostulatedHELBscenariosthatmayleadtofailureofredundantsafety-relatedsystems(seeLicenseeEventReports(LERs)316/98-005 and315/99-026fordetails).Withinthesetwoissuestherearethreescenariosthataredescribedbelow:
ÿAbreakinaUnit2mainsteamlineormainfeedwaterlinecoulddegradetheabilityofthecomponentcoolingwater(CCW)pumpsofbothunitstoperformtheirfunction.All
fiveCCWpumpsforCook1&2areinthesameroom.Thepumpsarenotqualifiedfor
theharshenvironmentofaHELB.Therefore,allofthepumpsmayfailonexposureto
thehighhumidityandhightemperaturescausedbyamainsteamlineoramain
feedwaterlinebreakinthepipechaseadjoiningtheroom.ML003760571 IN2000-20Page2of3ÿAbreakinthehigh-pressurefeedwaterheatersorassociatedpipingnearthedoortotheswitchgearroomcoulddegradetheabilityofbothtrainsof600Vsafety-relatedbuses.
Thedoorbetweentheswitchgearroomandtheturbinebuildingisnormallyopenand
maynotcloseintheeventofaHELB.Bothtrainsof600Vsafety-relatedbusesarein
theswitchgearroomandthebusesarenotqualifiedforaharshenvironment.
Therefore,bothtrainsofsafety-related600Vbusesmayfailonexposuretothehigh
humidityandhightemperaturesofaHELB.
ÿAHELBintheturbinebuildingcoulddegradetheabilityofallthreeauxiliaryfeedwater(AFW)pumps.Thedoortotheturbine-drivenAFWpumpisnormallyopenandmaynot
closeintheeventofaHELB.Thetwomotor-drivenAFWpumpsareinroomswhose
ventilationintakeisfromtheturbinebuilding.AFWpumpsarenotqualifiedforaharsh
environment.Therefore,allAFWpumpsmayfailonexposuretothehighhumidityand
hightemperaturesofaHELBintheturbinebuilding.
DiscussionConditionsconducivetoarisk-significantconfiguration
- Fourconditionsmustcoexisttoproducearisk-significantconfigurationlikethatatCook.Thesefourconditionsare(1)lackofaHELBbarrierbetweentheredundanttrainsofasystemthatis
neededtomitigateaccidents,(2)thelackofenvironmentalqualificationfortheredundant
componentsoftrainslocatedinthesamearea,(3)thepresenceofhigh-energypipingin
adjacentareas,and(4)thelackofaHELBbarrierbetweenadjacentpipingandtheredundant
safetysystemtrains.Relationshipoftherisk-significantconfigurationtoregulatoryguidance:Section3.6.1oftheStandardReviewPlan(SRP)andNRRPlantSystemsBranchTechnicalPositionSPLB3-1(formerlyAPCSB3-1)provideregulatoryguidanceontheplantdesignfor
protectionagainstpostulatedpipingfailuresoutsidecontainment.WhenSPLB3-1isusedasa
guidetomeettherequirementsoftheGeneralDesignCriterion4of10CFRPart50,
AppendixA,themethodusedtoconformwiththatregulatoryguidancedependsuponwhenthe
constructionpermitapplicationsweretenderedandtheoperatinglicensesissued.SectionB.4 ofSPLB3-1providesdetailsonthedependenceofitsapplicabilitytothedatesonwhich
constructionpermitsweretenderedoroperatinglicenseswereissued.GenericLetter87-11,issuedonJune11,1987,transmittedRevision2oftheMechanicalEngineeringBranch(MEB)TechnicalPositionMEB3-1.Thisrevisionprovidedadditional
guidanceonlocationswherepipebreaksshouldbepostulated.Revision2ofMEB3-1allows
theeliminationofpipe-whiprestraints,jet-impingementshields(placedtomitigatetheeffectsof
arbitraryintermediateruptures),andotherrelatedchanges.However,therevisiondoesnot
relievelicenseesfromtheneedtoconformtotheguidancerelatingtoHELBeffectsonessential
systemsandcomponents.Essentialsystemsandcomponentsaresystemsandcomponents
requiredtoshutdownthereactorandmitigatetheconsequencesofapostulatedpipingfailure, withoutoffsitepower.EventhoughapplicationofRevision2oftheMEB3-1pipebreakcriteria
maynotrequirepostulatingbreaksnearareasthathousetheredundantequipmentand
installingpiperestraints,licenseesareexpectedtocomplywiththeirlicensingbasisand
regulatorycommitmentsforpostulatingacrackatthelocationmostdamagingtothe
IN2000-20Page3of3essentialstructuresandsystems.Forexample,theGiambussoletterof1972(NUREG-0800,StandardReviewPlan3.16.1,AppendixB,Rev.2,October1999)specifiesthatwherepipes
carryinghigh-energyfluidsareroutednearstructuresandsystemsnecessaryforsafe
shutdownoftheplant,supplementalprotectionofthosestructuresandsystemsshallbe
providedtocopewiththeenvironmentaleffects(includingtheeffectsofjet-impingement)ofa
singlepostulatedopencrackatthelocationmostdamagingtothoseessentialstructuresand
systems.NUREG-1728,"AssessmentofRiskSignificanceAssociatedWithIssuesIdentifiedatD.C.CookNuclearPowerPlant,"Volumes1&2werepublishedinOctober2000.Thisreport
documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's
PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html
.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted
below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation
(NRR)projectmanager./RA/LedyardB.Marsh,ChiefEventsAssessment,GenericCommunicationsandNon-PowerReactorsBranchDivisionofRegulatoryImprovementPrograms
OfficeofNuclearReactorRegulationTechnicalcontacts:S.D.Weerakkody,RESY.C.Li,NRR301-415-6374301-415-2772 E-mail:sdw1@nrc.govE-mail:ycl@nrc.govC.D.Petrone,NRR301-415-1027 E-mail:cdp@nrc.govAttachment:ListofRecentlyIssuedNRCInformationNotices
IN2000-20Page3of3essentialstructuresandsystems.Forexample,theGiambussoletterof1972(NUREG-0800,StandardReviewPlan3.16.1,AppendixB,Rev.2,October1999)specifiesthatwherepipes
carryinghigh-energyfluidsareroutednearstructuresandsystemsnecessaryforsafe
shutdownoftheplant,supplementalprotectionofthosestructuresandsystemsshallbe
providedtocopewiththeenvironmentaleffects(includingtheeffectsofjet-impingement)ofa
singlepostulatedopencrackatthelocationmostdamagingtothoseessentialstructuresand
systems.NUREG-1728,"AssessmentofRiskSignificanceAssociatedWithIssuesIdentifiedatD.C.CookNuclearPowerPlant,"Volumes1&2werepublishedinOctober2000.Thisreport
documentstheresultsofananalysisoftherisksignificanceatD.C.CookNuclearPowerPlant, Units1&2sinceAugust1997.ThisNUREGmaybeaccessedelectronicallyattheNRC's
PublicElectronicReadingRoomatwww.nrc.gov/NRC/ADAMS/index.html
.Thisinformationnoticerequiresnospecificactionorwrittenresponse.Ifyouhaveanyquestionsabouttheinformationinthisnotice,pleasecontactoneofthetechnicalcontactslisted
below,theappropriateregionaloffice,ortheappropriateOfficeofNuclearReactorRegulation
(NRR)projectmanager./RA/LedyardB.Marsh,ChiefEventsAssessment,GenericCommunicationsandNon-PowerReactorsBranchDivisionofRegulatoryImprovementPrograms
OfficeofNuclearReactorRegulationTechnicalcontacts:S.D.Weerakkody,RESY.C.Li,NRR301-415-6374301-415-2772 E-mail:sdw1@nrc.govE-mail:ycl@nrc.govC.D.Petrone,NRR301-415-1027 E-mail:cdp@nrc.govAttachment:ListofRecentlyIssuedNRCInformationNoticesDISTRIBUTION:INFilePUBLICAccessionNo.:ML003760571Toreceiveacopyofthisdocument,indicateintheboxC=Copyw/oattachment/enclosureE=Copywithattachment/enclosureN=NocopyOFFICEREXBTechEdDLPMEMEBSPSBRESC:REXBNAMECPetronePKleeneJStangEImbroRBarrettPBaranowsky*LMarsh
DATE//0010/10/00*11/18/00*11/30/00*12/4/00*12/5/0012/11/00OFFICIALRECORDCOPY
______________________________________________________________________________________OL=OperatingLicense
CP=ConstructionPermitAttachmentIN2000-20
Page1of1LISTOFRECENTLYISSUEDNRCINFORMATIONNOTICES
_____________________________________________________________________________________InformationDateof
NoticeNo.SubjectIssuanceIssuedto
______________________________________________________________________________________2000-19ImplementationofHumanUseResearchProtocolsInvolving
U.S.NuclearRegulatory
CommissionRegulated
Materials12/05/2000Allmedicaluselicensees2000-18SubstandardMaterialSuppliedbyChicagoBulletProof
Systems11/29/2000All10CFRPart50licenseesandapplicants.Allcategory1fuel
facilities.All10CFRPart72 licenseesandapplicants2000-17S1CrackInWeldAreaofReactorCoolantSystemHotLegPiping
AtV.C.Summer11/16/2000AllholdersofOLfornuclearpowerreactorsexceptthosewho
haveceasedoperationsandhave
certifiedthatfuelhasbeen
permanentlyremovedfromthe
reactorvessel2000-17CrackInWeldAreaofReactorCoolantSystemHotLegPiping
AtV.C.Summer10/18/2000AllholdersofOLfornuclearpowerreactorsexceptthosewho
haveceasedoperationsandhave
certifiedthatfuelhasbeen
permanentlyremovedfromthe
reactorvessel2000-16PotentialHazardsDuetoVolatilizationofRadionuclides10/5/2000AllNRClicenseesthatprocessunsealedbyproductmaterial2000-15RecentEventsResultinginWholeBodyExposures
ExceedingRegulatoryLimits9/29/2000Allradiographylicensees2000-14Non-VitalBusFaultLeadstoFireandLossofOffsitePower9/27/2000AllholdersofOLfornuclearpowerreactors2000-13ReviewofRefuelingOutage
Risk9/27/2000AllholdersofOLfornuclearpowerreactors2000-12PotentialDegradationofFirefighterPrimaryProtective
Garments9/21/2000Allholdersoflicensesfornuclearpower,research,andtest
reactorsandfuelcyclefacilities