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-0 U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORTQi{PLEASEPRINTORTYPEALLREQUIREDINFORMATION) 600000-00Q341111QE~QRLICENSENUMBER2526LICENSETYPE3057CAT58CON'T,~078~03~04~OS~06R"DRT~L~B0500024471207798122179QgSOURCE6061DOCKETNUMBEREVENTDATE7475REPORTDATE80EVENTDESCRIPTION ANDPROBABLECONSEQUENCES Q10Duringnormalinservice inspection ofpressurizer reliefnozzle-to-safe-end weld,liquidpenetrant exa'mshowedlinearindications l-l/8"and3/8"long.(T.S.6.9.2.a(3))UTdidnotshowany.FollowupX-rayexamshowednovolumetric indications.

Furtherliquidpenetrant andreplication showedareaofattack6-7"by1/8"consisting ofafamilyoffinecrackssimilartointergranular typeattack.Allpressurizer headnozzle-to-safe-end weldareaswereexaminedwithUTandliquidpenetrant withno~0878otherrelevantindications noted.80~OgSYSTEMCAUSECAUSECOMP.VALVECODECODESUBCODECOMPONENT CODESUBCODESUBCODE~CBQ>>'~EQ12~DQTRP1PEXXQ14~BQEE~ZQs78910111213181920SEQUENTIAL OCCURRENCE REPORTREVISIONLERIROEVENTYEARREPORTNO.CODETYPENO.Q17REPQRT~79+~023QX~01QT-QO2122232426272829303132ACTIONFUTUREEFFECTSHUTDOWNATTACHMENT NPRDXPRIMECOMP.COMPONENT TAKENACTIONONPLANTMETHODHOURS~22SUBMITTED FORMSUB.SUPPLIERMANUFACTURER

~BQTR~XPTg~APER~AP270416~YP23~YQ24~NQ25Y17120QER3334353637404'I42434447CAUSEDESCRIPTION ANDCORRECTIVE ACTIONSQ270Possiblecauses:originalfabrication contamination orchlorideconcentration occurring duringoperation.

Investigation includesexamining boatsamplewithscanningelectronmicroscope todetermine corrosive species,andinsulation leachinchemicalanalsis.34Clothcoverreplacedwithfiberglass.

Reportofmetallurgical analysisresultstobesubmitted later.Pressurizer headnozzle-to-safe-end weldareastobereexamined in1980AI&O.789FACILITYSTATUS%POWERs~GQEs~000PER789101213ACTIVITYCONTENTRELEASEDOFRELEASEAMOUNTOFACTIVITYQ3s6~~Q33~+Q34NA7891011PERSONNEL EXPOSURES NUMBERTYPEDESCRIPTION Q3g~77~000Q37ZQssNA78911'1213PERSONNEL INJURIESLOCATIONOFRELEASEQB4445METHODOFOTHERSTATUSQDISCOVERY DISCOVERY DESCRIPTION Q32NA~BQ3IRoutineISI444546808080807891112LOSSOFORDAMAGETOFACILITYQ43TYPEDESCRIPTION g~ZQ42NA78910PUBLICITY ISSUEDDESCRIPTION

~XQ44NewsreleasewasmadeDecemberll,1979.78910A.E.CurtisIIINAMEOFPREPARER8080NRCUSEONLYEgI686980o16/546-2700,ext.

2329,

Attachnant tcLER79+3/01T-0 Rochester GasandElectricCorporation R.E.GinnaNuclearPowerPlant,UnitNo.1DocketNo.50-244EventDescritionOnFriday,December7,1979,duringanormalinservice inspection programexamination onthepressurizer reliefnozzle-to-safe-end weld,linearindications l-l/8"longand3/8"longwerenotedbytheliquidpene-trantexamination method.Theultrasonic examination performed didnotrevealanyindications.

OnSaturday, December8,1979,theareaoftheindications waspreparedbymechanical meanswithaflapperwheelandlightgrinding.

Areexamination withliquidpenetrant revealedanareaofattackapproximately 6-7incheslongby1/8"wide.Duetootherworkbeingperformed inthepressurizer headareasupplementary examinations werenotperformed untilSundaynight,December9,1979.Theseexamina-tionsincludedmoreliquidpenetrant examinations andradiographic g-ray)examination oftheareawheretheoriginalliquidpenetrant indication wasfound.Theradiographs oftheaffectedarearevealednoapparentvolumetric indications.

Supplemental ultrasonic examinations oftheareaalsorevealednoapparentvolumetric indications.

Inplacemetallography wasattempted withoutmuchsuccessduetotherestrictions imposedbythepipingsystemthatattachestothereliefnozzle.Replication usingaplasticmaterialrevealedafamilyofveryfinecracks.Ina2inchlongareatheindications wereground*out ahabout1/8inchdepth.Confirmation ofthisfindingoccurredwheninanadditional 3inchlongareatheindications weregroundoutafterlessthan1/8ofaninchofmaterialwasremoved.OnWednesday, December12,1979,aboatsamplewasremovedforfurtherinvestigation andanalysisofthecracks.Theresultsoftheinvestigations madeinthefieldrevealedthatthecrackswereinthe309weldmaterialthatwasusedforthedissimilar weldbetweenthecarbonsteelnozzle(SA-216-GR.WCC) andthestainless steel'safe-end material(SA-182TP,316)andnotthesafe-endmaterialasoriginally thought.Therepairprocedure includedremovaloftheremaining crackedmate-rial,preparing theexcavated areaforweldrepairandweldingwiththeGasTungstenArcWeldingProcessutilizing ER-309basefillermetal.Postprep-aration,firstweldpassandfinalweldliquidpenetrant examinations wereperformed.

Afinalweldpreservice ultrasonic examination oftherepairedareawasalsoperformed.

Theresultsofallexaminations didnotrevealanyindications

.Alsoexaminedduringthisinvestigation wereallthenozzle-to-safe-endweldareasonthepressurizer headutilizing theliquidpenetrant andultrasonic examination methods.Theultrasonic examinations includedanormalinservice inspection technique andaspecialstresscorrosion tech-

~+

Attachment toLER79-3/01T-02.nique.Weldsinassociated pipingofthefournozzleswerealsoexaminedutilizing theliquidpenetrant methodwithnofurtherrelevantindications noted.Therewerenohealthorsafetyconsequences tothepublicortoplantpersonnel duetothisevent.CauseDescritionReplication oftheaspolishedweldsurfacerevealedaverytightcrackpattern,similartoanintergranular stresscorrosion.

Theboatsampleanalysisrevealedthreecracksasfollows:Crack41-1.4mmfromcarbonsteelfusionline0.4mmindepthCrack42-2.3mmfromcarbonsteelfusionline0.7mmindepthCrack43-3.5mmfromcarbonsteelfusionline1.1mmindepthtouchingcarbonsteelbevelFurtheranalysisutilizing thescanningelectronmicroscope isongoingtodetermine ifanycorrosive speciescanbeidentified.

Presently onlyspeculation canbemadeonthecauseofthiscracking.

Itmayhavebeencausedbyoriginalfabrication contamination orbyachlorideconcentration thathasoccurredduringoperation.

Aspartofthisinvestigation achemicalanalysisofleachable contaminants fromthethermalinsulation thatsurrounded thereliefnozzlewasperformed asprescribed inRegulatory Guidel.36,Nonmetallic ThermalInsulation forAustenitic Stainless Steel.Theresultsofthisanalysisareasfollowsforsample1-wovenclothcoverandsample2-glassfibrouslayeredmaterial:

SamplePPMPPMCIFPPMPPMCI+FNaPPMSi03PPMNa+Si03989.4107.4100207307301.631.64099139Basedonthisanalysisaccording toFigureIofRegulatory Guide1.36,Sample2-theglassinsulation isacceptable, howeverSample1-theclothcoverisnotwithintheacceptable region.Althoughitwouldbelogicaltoassumethattheinsulating clothprovidedthechlorides thatmighthavecausedthiscrackingphenomena, theclothcouldhavebeencontaminated duringthehandlingofremoval.Therefore, theresultsofthescanningelectronmicro-scopewillhavetobefurtheranalyzedbeforeconfirming theinsulation involvement.

n Attachment toLER79-3/01T-0Aspartofthecorrective actiontheinsulation materialwaschangedonthepressurizer nozzlestoassurethatpotential leachable contaminants frominsulating materialwillrequirenofurtherconsideration.

Alsoeachnozzle-to-safe-end areawascleanedtoremoveanycontaminants priortoreinsulation.

Afullreportonthefinalresultsofthemetallurgical analysiswillbesubmitted whentheinvestigations arecomplete.

Thesenozzle-to-safe-endweldareaswillbereexamined duringthe1980refueling andmain-tenanceoutage.