ML17261A160

LER 79-023/01T-0:on 791207,during Inservice Insp of Pressurizer Relief nozzle-to-safe-end Weld,Liquid Penetrant Examination Showed Linear Indications.Possibly Caused by Original Fabrication Contamination or Chloride

ML17261A160
Person / Time
Site:	Ginna
Issue date:	12/21/1979
From:	CURTIS A E ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17249A361	List: ML17249A360 ML17261A160
References
LER-79-023-01T, LER-79-23-1T, NUDOCS 7912270442
Download: ML17261A160 (8)

Text

NRCFORM366I7.77+78CONTROLBLOCK:INYREG1Q2009LICENSEECODE141579-023/01T-0U.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTQi{PLEASEPRINTORTYPEALLREQUIREDINFORMATION)600000-00Q341111QE~QRLICENSENUMBER2526LICENSETYPE3057CAT58CON'T,~078~03~04~OS~06R"DRT~L~B0500024471207798122179QgSOURCE6061DOCKETNUMBEREVENTDATE7475REPORTDATE80EVENTDESCRIPTIONANDPROBABLECONSEQUENCESQ10Duringnormalinserviceinspectionofpressurizerreliefnozzle-to-safe-endweld,liquidpenetrantexa'mshowedlinearindicationsl-l/8"and3/8"long.(T.S.6.9.2.a(3))UTdidnotshowany.FollowupX-rayexamshowednovolumetricindications.Furtherliquidpenetrantandreplicationshowedareaofattack6-7"by1/8"consistingofafamilyoffinecrackssimilartointergranulartypeattack.Allpressurizerheadnozzle-to-safe-endweldareaswereexaminedwithUTandliquidpenetrantwithno~0878otherrelevantindicationsnoted.80~OgSYSTEMCAUSECAUSECOMP.VALVECODECODESUBCODECOMPONENTCODESUBCODESUBCODE~CBQ>>'~EQ12~DQTRP1PEXXQ14~BQEE~ZQs78910111213181920SEQUENTIALOCCURRENCEREPORTREVISIONLERIROEVENTYEARREPORTNO.CODETYPENO.Q17REPQRT~79+~023QX~01QT-QO2122232426272829303132ACTIONFUTUREEFFECTSHUTDOWNATTACHMENTNPRDXPRIMECOMP.COMPONENTTAKENACTIONONPLANTMETHODHOURS~22SUBMITTEDFORMSUB.SUPPLIERMANUFACTURER~BQTR~XPTg~APER~AP270416~YP23~YQ24~NQ25Y17120QER3334353637404'I42434447CAUSEDESCRIPTIONANDCORRECTIVEACTIONSQ270Possiblecauses:originalfabricationcontaminationorchlorideconcentrationoccurringduringoperation.Investigationincludesexaminingboatsamplewithscanningelectronmicroscopetodeterminecorrosivespecies,andinsulationleachinchemicalanalsis.34Clothcoverreplacedwithfiberglass.Reportofmetallurgicalanalysisresultstobesubmittedlater.Pressurizerheadnozzle-to-safe-endweldareastobereexaminedin1980AI&O.789FACILITYSTATUS%POWERs~GQEs~000PER789101213ACTIVITYCONTENTRELEASEDOFRELEASEAMOUNTOFACTIVITYQ3s6~~Q33~+Q34NA7891011PERSONNELEXPOSURESNUMBERTYPEDESCRIPTIONQ3g~77~000Q37ZQssNA78911'1213PERSONNELINJURIESLOCATIONOFRELEASEQB4445METHODOFOTHERSTATUSQDISCOVERYDISCOVERYDESCRIPTIONQ32NA~BQ3IRoutineISI444546808080807891112LOSSOFORDAMAGETOFACILITYQ43TYPEDESCRIPTIONg~ZQ42NA78910PUBLICITYISSUEDDESCRIPTION~XQ44NewsreleasewasmadeDecemberll,1979.78910A.E.CurtisIIINAMEOFPREPARER8080NRCUSEONLYEgI686980o16/546-2700,ext.2329,

AttachnanttcLER79+3/01T-0RochesterGasandElectricCorporationR.E.GinnaNuclearPowerPlant,UnitNo.1DocketNo.50-244EventDescritionOnFriday,December7,1979,duringanormalinserviceinspectionprogramexaminationonthepressurizerreliefnozzle-to-safe-endweld,linearindicationsl-l/8"longand3/8"longwerenotedbytheliquidpene-trantexaminationmethod.Theultrasonicexaminationperformeddidnotrevealanyindications.OnSaturday,December8,1979,theareaoftheindicationswaspreparedbymechanicalmeanswithaflapperwheelandlightgrinding.Areexaminationwithliquidpenetrantrevealedanareaofattackapproximately6-7incheslongby1/8"wide.DuetootherworkbeingperformedinthepressurizerheadareasupplementaryexaminationswerenotperformeduntilSundaynight,December9,1979.Theseexamina-tionsincludedmoreliquidpenetrantexaminationsandradiographicg-ray)examinationoftheareawheretheoriginalliquidpenetrantindicationwasfound.Theradiographsoftheaffectedarearevealednoapparentvolumetricindications.Supplementalultrasonicexaminationsoftheareaalsorevealednoapparentvolumetricindications.Inplacemetallographywasattemptedwithoutmuchsuccessduetotherestrictionsimposedbythepipingsystemthatattachestothereliefnozzle.Replicationusingaplasticmaterialrevealedafamilyofveryfinecracks.Ina2inchlongareatheindicationswereground*outahabout1/8inchdepth.Confirmationofthisfindingoccurredwheninanadditional3inchlongareatheindicationsweregroundoutafterlessthan1/8ofaninchofmaterialwasremoved.OnWednesday,December12,1979,aboatsamplewasremovedforfurtherinvestigationandanalysisofthecracks.Theresultsoftheinvestigationsmadeinthefieldrevealedthatthecrackswereinthe309weldmaterialthatwasusedforthedissimilarweldbetweenthecarbonsteelnozzle(SA-216-GR.WCC)andthestainlesssteel'safe-endmaterial(SA-182TP,316)andnotthesafe-endmaterialasoriginallythought.Therepairprocedureincludedremovaloftheremainingcrackedmate-rial,preparingtheexcavatedareaforweldrepairandweldingwiththeGasTungstenArcWeldingProcessutilizingER-309basefillermetal.Postprep-aration,firstweldpassandfinalweldliquidpenetrantexaminationswereperformed.Afinalweldpreserviceultrasonicexaminationoftherepairedareawasalsoperformed.Theresultsofallexaminationsdidnotrevealanyindications.Alsoexaminedduringthisinvestigationwereallthenozzle-to-safe-endweldareasonthepressurizerheadutilizingtheliquidpenetrantandultrasonicexaminationmethods.Theultrasonicexaminationsincludedanormalinserviceinspectiontechniqueandaspecialstresscorrosiontech-

~+

AttachmenttoLER79-3/01T-02.nique.Weldsinassociatedpipingofthefournozzleswerealsoexaminedutilizingtheliquidpenetrantmethodwithnofurtherrelevantindicationsnoted.Therewerenohealthorsafetyconsequencestothepublicortoplantpersonnelduetothisevent.CauseDescritionReplicationoftheaspolishedweldsurfacerevealedaverytightcrackpattern,similartoanintergranularstresscorrosion.Theboatsampleanalysisrevealedthreecracksasfollows:Crack41-1.4mmfromcarbonsteelfusionline0.4mmindepthCrack42-2.3mmfromcarbonsteelfusionline0.7mmindepthCrack43-3.5mmfromcarbonsteelfusionline1.1mmindepthtouchingcarbonsteelbevelFurtheranalysisutilizingthescanningelectronmicroscopeisongoingtodetermineifanycorrosivespeciescanbeidentified.Presentlyonlyspeculationcanbemadeonthecauseofthiscracking.Itmayhavebeencausedbyoriginalfabricationcontaminationorbyachlorideconcentrationthathasoccurredduringoperation.AspartofthisinvestigationachemicalanalysisofleachablecontaminantsfromthethermalinsulationthatsurroundedthereliefnozzlewasperformedasprescribedinRegulatoryGuidel.36,NonmetallicThermalInsulationforAusteniticStainlessSteel.Theresultsofthisanalysisareasfollowsforsample1-wovenclothcoverandsample2-glassfibrouslayeredmaterial:SamplePPMPPMCIFPPMPPMCI+FNaPPMSi03PPMNa+Si03989.4107.4100207307301.631.64099139BasedonthisanalysisaccordingtoFigureIofRegulatoryGuide1.36,Sample2-theglassinsulationisacceptable,howeverSample1-theclothcoverisnotwithintheacceptableregion.Althoughitwouldbelogicaltoassumethattheinsulatingclothprovidedthechloridesthatmighthavecausedthiscrackingphenomena,theclothcouldhavebeencontaminatedduringthehandlingofremoval.Therefore,theresultsofthescanningelectronmicro-scopewillhavetobefurtheranalyzedbeforeconfirmingtheinsulationinvolvement.

n AttachmenttoLER79-3/01T-0Aspartofthecorrectiveactiontheinsulationmaterialwaschangedonthepressurizernozzlestoassurethatpotentialleachablecontaminantsfrominsulatingmaterialwillrequirenofurtherconsideration.Alsoeachnozzle-to-safe-endareawascleanedtoremoveanycontaminantspriortoreinsulation.Afullreportonthefinalresultsofthemetallurgicalanalysiswillbesubmittedwhentheinvestigationsarecomplete.Thesenozzle-to-safe-endweldareaswillbereexaminedduringthe1980refuelingandmain-tenanceoutage.