ML17206A516

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Requests Relief from ASME Code Requirements Re Ultrasonic Examinations of Piping Welds.Recording & Eval Indications at 20% DAC Is Impractical.Primary Reference level(100% DAC) Criteria for UT Exam Provides Comparable Safety Level
ML17206A516
Person / Time
Site: Saint Lucie, Turkey Point  NextEra Energy icon.png
Issue date: 11/15/1978
From: UHRIG R E
FLORIDA POWER & LIGHT CO.
To: STELLO V
Office of Nuclear Reactor Regulation
References
L-78-361, NUDOCS 7811210338
Download: ML17206A516 (6)


Text

QvOb..REGULATOR INFORMATION DISTRIBUTION TEMDOCKETNBR.-50-250/251~RKEY PT3/4DQCDATE:781115RECIPIENT:

ACCESSION NBR:7811210338 ORIGINATOR-UHRIG,R.E.COPIESRECEIUED:

COMPANY.FLPVR&LIGHTLTR3ENCL

SUBJECT:

SIZE:4RequestsrelieffromASMECodeReqsreUltrasonic Examinations ofPipingWelds.Recording

&evalindications at20%DACisimpractical.

Primaryreference level(100%DAC)criteriaforUTexamination providescomparable'afety'evel.'1 STRTPIITIQN COOEt800bQIST@IPLITI()N TITLE'!RFa(IESTSFOREXEI.PTIOTAS(ALITYPES)NOTARIZED BRCHIEF'ROJ v(:RF'4RCPrRLEJI"ILI.E>T~BELLI.PDRACRSTOT>LN(jPHERENCL7w/ENCLHIE'>CL'w/ENCLiu/ENCLw/FNCL>'/2ENCLW/ENCLw/P'NCL~~Al2.6Hc~w/1bENCLQFCOPIESREQUIRED!

LTRENCLIFORACTIONDEISENHUTORB//1BGRIMESORB(f4BCPERICKSONORB(/4LA2b26IOY2pHieNOTES:

P.O.BOX013100,MIAMI,FL33101FLORIDAPOWER&LIGHTCOIiIPANY OfficeofNuclearReactorRegulation Attention:

Mr.VictorStella,DirectorDivisionofOperating ReactorsU.S.NuclearRegulatory Commission Llashington, D.C.20555

DearMr.Stello:

November15,1978L-78-361Re:TurkeyPointUnits3&4,St.LucieUnit1DocketNos.50-250,50-251&50-33510CFR50.55a(g)

(5),RequestforReliefUltrasonic Examinations ofPiinMeldsFloridaPower&LightCompanyhasdetermined thatconformance withcertaincoderequirements concerning ultrasonic examination ofpipingweldswouldbeimpractical forTurkeyPointUnits3&4andSt.LucieUnitl.Therefore, pursuantto10CFR50.12and10CFR50.55a(g)

(5),arequestforrelieffromthecoderequirements, including information insupportofourdetermination, isattached.

Additional requestsforreliefarebeingconsidered, buthavenotbeencompletely formulated atthistime.Forexample,asaresultofmeetingswiththeNRCstaffatourcorporate headquarters duringtheperiodMay3-5,1978,itwasdetermined thatsomevalvesinthevalvetestingprogramwerenosafetyrelated,sotheyweredeletedfromtheprogram.Therefor, weareconsidering arequesttoexemptthesystemsandcomponents contiguous withthesenon-safety relatedvalvesfromtheexamination requirements oftheinservice inspection program.Additional requestsforreliefwillbeforwarded toyourofficeastheyaredeveloped.

Veryt1yours,RobertE.UhrigVicePresidentREU/MAS/cpc Attachment cc:Mr.JamesP.O'Reilly, RegionIIHaroldF.Reis,EsquiregalV811210'~&iqPEOPLE...SERVINGPEOPLE ATTACHi~1ENT Re:TurkeyPointUnits3&4andSt.LucieUnit1DocketNos.50-250,50-251,and50-335ReuestforRelieffromAS?4ECodeReouirements I.APPLICABILITY FloridaPower&LightCompanyrequestsrelieffromthebelowlistedCodeRequirements astheyapplytoultrasonic examination ofpipingweldsatTurkeyPointUnits3&4andSt.LucieUnit1(Class1&2).II.CODEREQUIREMENTS A.ASNECodeSectionXI(1974Edition),

Paragraph IWA-2232, Ultrasonic Examination:

"Ultrasonic examination shallbeconducted inaccordance withtheprovisions ofAppendixI.WhereAppendixI(I-1200)isnotapplicable, theprovisions ofArticle5ofSectionVshallapply."B.ASNECodeSectionV(1974'Edition),

Paragraph T-537,Evaluation ofIndications:

"Allindications whichproducearesponsegreaterthan20percentofthereference levelshallbeinvestigated totheextent.thattheoperatorcanevaluatetheshape,identity, andlocationofallsuchreflectors intermsoftheacceptance-rejection standards ofthereferencing CodeSection."

III.BASISFORRELXEFA.The20%DAC(distance-amplitude correction) criteriaofparagraph T-537ofSectionVisimpractical.

IV.B.Theprimaryreference level(100%DAC)criteriafortheultrasonic (UT)examination ofpipingweldsprovidesalevelofsafetycomparable totheSectionVstandards.

DISCUSSXON A.Recording andevaluating indications at20%DACisimpractical forthefollowing reasons:1.Theweldedjointsinnuclearpipingfrequently containCodeallowable wallthickness differences (12%ofnominalthickness) aswellassomewelddrop-through, counterbore taper,crownheight,etc.Theseconditions generateanextremely largenumberofgeometric reflectors whichproduceUTindications greaterthan20%DAC.

2.Weldmetalinstainless steelpipingcontainsreflect,-

orsduetothemetallurgical structure whichproducealargenumberofUTindications.

3.Althoughstresscorrosion crackinginstainless steelhasbeenfoundtoexistinlowlevelamplitudes, experience hasshownthatthetypicalmodeoffailureinthistypeofcrackingisnotintheweldmetalperse,butintheheataffectedzone(HAZ)andbasemetalofthepipe.Anexperienced UToperatorcandiscriminate stresscorrosion cracksfromgeometric andmetallurgical reflectors.

Thus,itisnotneces-sarytorecordandevaluateallreflectors asSectionVrequires, butonlythosewhicharerealflaws.Itshouldalsobenotedthattherecording ofrealflawsisdoneregardless ofCodeevaluation criteria(insofaraspercentage ofDACisconcerned) aspartofgoodexamination practice.

4.Allexamination personnel experience radiation ex-posureduringinservice examinations.

TheSectionVrequirement torecordandevaluateUTindications atthe20%DACplacesanunnecessary burdenonthelimit-ednumberofexperienced andqualified.

examiners=

available totheowner.B.Theprimaryreference evaluation (100%DAC)ofindications establishes anadequatelevelofinformation forthefol-lowingreasons:Historically, SectionXIestablishes the20%DACeval-uationcriteriabyreferencing otherSectionsotheASNECode.Forexample,Paragraph IS-213.2ofthe1970Codeandthe1971Codereferences AppendixIXofSectionIII.Also,asquotedaboveinpart.IIofthisAttachment, Paragraph IPlA-2232 ofthe=1974Codereer-encesArticle5ofSectionV.Until1976,.-.when 10CFR50.55a(g)requiredinservice inspection programstobeupgradedtothe1974EditionofSectionXI,mostoftheseprogramshadbeenconducted inaccordance withParagraph IS-213.2oftheSummer1971AddendatoSectionXI.Theseprogramsinvokedthe100%DACevaluation criteriaandtookexception tothe20%DACevaluation criteriaofAppendixIXofSectionIII.Suchprogramswereverysuccessful andprovidedacomprehensive safety,levelforthecomponents examined.

2.TheSummer1973AddendaandtheWinter1975Addenda,withtheintroduction ofAppendixIforvesselUTexamination andAppendixIIIforpipingUTexamination, confirmed theASNESectionXICommittee positionon50-:-DACrecording and100%DACevaluation ofUTindications.

Inaddition, the100%DACevaluation criteriaforindic-ationsfoundduringUTexamination ofpipingweldswasreconfirmed bythe1977EditionoSectionXI[Paragraph INA-2232(b)(l) andIII-4500(1)].

V.ALTERNATIVE EVALUATION CRITERIAA.Indications 50%ofDACorgreatershallberecorded.

B.Anyindication 100%ofDACorgreatershallbeinvest-igatedbyaLevelIIorLevelIIIexaminertotheextentnecessary todetermine theshape,identity, andlocationofthereflector.

C.Anynon-geometric indication, regardless ofDAC,discovered duringtheUltrasonic (UT)examination ofpipingweldsandbasemetalmaterials shallberecordedandinvestigated byaLevelIIorLevelIIIexaminertotheextentnecessary todetermine theshape,identity, andlocationofthereflector.

D.Theownershallevaluateandtakecorrective actionforthedisposition ofanyindication investigated andfoundtobeotherthangeometric innature.

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