ML17261A139

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LER 79-008/03X-1 on 790406:during Maint on Boric Acid Flow Control Valve,Leaks Noted on Valve Outlet 1-inch Nipple. Caused by External Caustic Pitting.Actions to Minimize Caustics & Chlorides Are Being Taken
ML17261A139
Person / Time
Site: Ginna Constellation icon.png
Issue date: 08/21/1979
From: SPECTOR S
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17244A791 List:
References
LER-79-008-03X, LER-79-8-3X, NUDOCS 7908280731
Download: ML17261A139 (4)


Text

lINRCFORM366I7377ILER79-008/03X-1 I~!0178CONTROLBLOCK:INYREG1Q2009LICENSEECODE'1415U.S.NUCLEARREGULATORY COMMISSION UpdateReport-PreviousReportDate5/7/79~ENSEEEVENTREPORT~(CAR2229)Qi(PLEASEPRINTORTYPEALLREQUIREDINFORMATIONI 0-00Q'4PE~QELICENSENUMBER'2526LICENSETYPE3057CAT58<<CON'Ti~Oi78~LQB050002447040679s082179Q6061DOCKETNUMBER6869EVENTDATE7475REPORTDATE80EVENTDESCRIPTION ANDPROBABLECONSEQUENCES Q10Duringmaintenance onboricacidflowcontrolvalveleakswerenotedonvalveoutlet1~031nipple(T.S.6.9.2.b.(4)).TwoflowpathsfromboricacidtankstoRCSwere4verified.

Nipplewasreplacedwithsch40nipple.Later,nipples,checkvalveand<<~couplingfromcontrolvalvetocouplingwerereplaced.

~~<<0e(~O7I~os.78980I~Osanalysisidentified thiscombinedwiththroughwall chloridestresscorrosion cracking.

SYSTEMCAUSECAUSECOMP.VAI.VECODECODESUBCODECOMPONENT CODESUBCODESUBCODE~PCQ<<1EQ12UcQ13PIPEXXQ<<4UAP<<6~ZQ1678910111213181920SEQUENTIAL OCCURRENCE REPORTREVISIONLER)ROEVENTYEARREPORTNO.CODETYPENO.Q17REPORTL77I.UUOOOSJUH~03UXU12122232426272829303132ACTIONFUTUREEFFECTSHUTDOWNATTACHMENT NPRDQPRIMECOMP.COMPONENT TAKENACTIONONPLANTMETHODHOURSQ22SUBMITTED FORMSUB.SUPPLIERMANUFACTURER UcPT.UcPE UzPEUZP21oooo~XP23UNQ24UNP>>z999P263334353637404142434447CAUSEDESCRIPTION ANDCORRECTIVE ACTIONSQ27oSevereexternalcausticpittingprobablystartedprocesscausingleaks.Metallurgical 3Otherheattracedpipingareasinvolving similarconditions examined; noproblemsfound.Actionstominimizecausticsandchlorides onpipeduetoinsulation, heat4traceandothermaterials arebeintaken.'.789FACILITYSTATUS%POWEROTHERSTATUS7~18EQ28~092Q28NA78910121344ACTIVITYCONTENTRELEASEDOFRELEASEAMOUNTOFACTIVITY(~16~ZP33~ZP,NA789101144PERSONNEL EXPOSURES NUMBERTYPEDESCRIPTION Q39~000Q37~ZQ38NA789111213PERSONNEL INJURIESNUMBERDESCRIPTIONQ l~<<8~000Q46NA7891112LOSSOFORDAMAGETOFACILITYQ43TYPEDESCRIPTION LzIQENA8910PUBLICITY 4ISSUEDDESCRIPTION

~'H~ZPJQ44NA8910METHODOFDISCOVERY DISCOVERY DESCRIPTION Q32~AQ31Noticeddurinmaintenance onadacent4546vve80LOCATIONOFRELEASEQ8080458080790838073 (80NRCUSEONLY68698048PHoNE.716546-2700ext.291-215S.SpectorNAMEOFPREPARERj~j2The1"nippleis3-',"longsch10SS,heattraced,normaloperating pressure100psig.

1 Attachment toLER79-008/03X-1 Rochester GasandElectricCorporation R.E.GinnaNuclearPowerPlant,UnitNo.1DocketNo.50-244W9ileperforming maintenance onboricacidflowcontrolvalvePCV-llOA, aleakwasnotedontheadjacentpiping.TwoflowpathsfromtheboricacidtankstotheReactorCoolantSystemwereverified.

Theleakingpipesectionwasa3-',"long1"schedule10stainless steel.Itisheattracedandnormaloperating pressureis100psig.Theexternalsurfaceexhibited numerousdeeppittingholes.Thenipplewasreplaced, andlaterthe.nipple,adjacentcheckvalve,nippleandcouplingwerereplaced.

Metallurgical analysishasidentified themechanism causingtheleakstobeseverecausticpittingcombinedwiththroughwall chloridestresscorrosion cracking.

Seventeen sectionsofheattracedstainless steelpiping,containing varyingconcentrations ofboricacid,havebeenrandomlyselectedforexternalvisualinspection todetermine theextentoftheproblem.Parti-cularinterestwasgiventoareasofhighstressandareasthatmayhavehadnumerouswetting/drying cyclesduetoaccidental spillsorleakingvalves.Theseinspections revealedthatallthepipingwasinexcellent condition, withnosignsofthisphenomenon.

Thesefindingsindicatethatlocalexternalcausesprobablyinitiated thisprocess,andthereplacement ofpiping,valveandfittingsinthisareashouldresolvetheproblem.Actionstofurtherminimizechlorideandcausticsonthepipingduetoinsulation, heattracingandothermaterials arebeingtaken.