Revision3July1990InserviceInspectionOfUngroutedTendonsinPrestressedConcreteContainmentsRegulatoryGuide1.35(TASKSC810-4)[DivisionIndex|RegulatoryGuideIndex|NRCHomePage]TableofContentsA.IntroductionB.DiscussionC.RegulatoryPositionD.ImplementationoRegulatoryAnalysisA.IntroductionGeneralDesignCriterion53,ProvisionsforContainmentTestingandInspection,ofAppendixA,General.DesignCriteriaforNuclearPowerPlants,to10CFRPart50,DomesticLicensingofProductionandUtilizationFacilities,requires,inpart,thatthereactorcontainmentbedesignedtopermit(1)periodicinspectionofallimportantareasand(2)anappropriatesurveillanceprogram.ThisguidedescribesabasisacceptabletotheNRCstafffordevelopinganappropriateinserviceinspectionandsurveillanceprogramforungroutedtendons(1)inprestressedconcretecontainmentstructuresoflight-water-cooledreactors.TheAdvisoryCommitteeonReactorSafeguardshasbeenconsultedconcerningthisguideandhasconcurredintheregulatoryposition.Anyinformationcollectionactivitiesmentionedinthisregulatoryguidearecontainedasrequirementsin10CFRPart50,whichprovidestheregulatorybasisforthisguide.Theinformationcollectionrequirementsin10CFRPart50havebeenclearedunder0MBClearanceNo.3150-0011.B.DiscussionFollowingtheissuanceforpubliccommentoftheproposedRevision3ofthisregulatoryguide(TaskSC810-4)andoftheaccompanyingproposedRegulatoryGuide1.35.1(TaskSC807-4)inApril1979,theNRCOfficeofResearchawardedacontracttoOakRidgeNationalLaboratory(ORNL).Thecontractworkincludedevaluatingactualinspectionsperformedbylicensees,themethodsofimplementingRevision2ofthisguide,andtheopinionsandproblemsofutilities,A/Es,vendors,etc.,relatedtoRevision2ofthisregulatoryguide.ThecontractoralsoconsideredthepertinentportionoftheJanuary1982draftversionofInserviceInspectionofConcretePressureComponents,developedbyaWorkingGroupofASMESectionXI,inmakingfinalsuggestionsformodifyingthisguide.ThesesuggestionswerepublishedinNUREG/CR-2719.(2)Thisguidehasbeenrevisedtoreflectpubliccomments,suggestionsfromORNL,andadditionalstaffreview.RegulatoryPosition1providesgeneralinformationontheapplicabilityoftheguide,frequencyofinserviceinspections,andinspectionswhentherearetwocontainmentsatasite.RegulatoryPosition2delineatesthemethodofdeterminingsamplesizeandemphasizesrandomsampling.Ifrandomsamplingcannotbeassured,itisacceptabletoselectrepresentativesamplesfrombetweenthepairsofbuttressesandfromvariousheights.Thesamplesforeachinspectionmaybeselectedanytimepriortotheinspection.Sinceinspectionscanbeperformedwhentheplantisoperating,theremaybecertainareaswhereinspectionofarandomlyselectedtendonmightresultinsomeradiologicalexposuretotheinspectingpersonnel.Thepositionprovidesforsubstitutingareadilyaccessibletendonforsuchatendon.RegulatoryPosition3describestheareasandextentofvisualexaminationsduringeachinspection.RegulatoryPosition4presentsthecriteriaforperformingprestressmonitoringtests.RegulatoryPosition5statestheextentandscopeoftendonmaterialtesting.RegulatoryPosition6listsitemsthatshouldbeconsideredintheinspectionofsheathingfillergrease.Inordertoassessthepotentialgreaseleakage,arecommendationismadetocomparetheamountofsheathingfillergreaseremovedwiththatbeingreplaced.RegulatoryPosition7discussestheindividualcriteriaforevaluatinginspectionresultsasfollows:InRegulatoryPosition7.1,prestressmonitoringcriteriahavebeendevelopedtoensurethatanysignsofsystematictendonforcedegradationaredetectedandinvestigated.Acceptanceof95%ofthepredictedforcefortwotendonsoutofthreeinRegulatoryPosition7.1.3isaslightlyrelaxedcriterionfromRevision2oftheguide.Itshouldberecognized,however,thattheprimaryobjectiveistocomparethemeasuredtendonforcesagainstthepredictedforcesatthetimeofthelift-offtesting.RegulatoryGuide1.35.1providesguidanceonestablishingthepredictedforces.Aprovisionhasbeenaddedtochecktheaverageofmeasuredforcesagainsttheminimumrequiredforceinanaverage(hypothetical)tendoninagroup.Thisprovisionisaddedasaresultofasuggestionfromthecontractor(ORNL)andpubliccomments.Itshouldberecognizedthateachindividualtendonforce(measured)willhavetobemodifiedtoreflecttheconditionofanaveragetendon.Thecontributingmodifyingfactorswouldbethedifferenceininstallationforcesandintheelasticshorteninglosses,assumingthetime-dependentcharacteristicsremainessentiallythesameforthegroupoftendons.Thelossofprestressfromcreepandshrinkageofconcreteandstressrelaxationofthetendonsteelaretime-dependentandarepredictedonsuchabasis.Thepredictedtendonforcemayberepresentedbyaslopedlineinasemi-logarithmicgraph.Thetrendoftheactualeffectivetendonforceisobtainedbyjoiningthepointsonthegraphrepresentingthemeasuredtendonforcesintwoormoresurveillancesofthesametendonortendonsinagroup.Byextendingthetrendline,onecandeterminewhentheeffectivetendonforcewillbebelowtheminimumrequired.RegulatoryPosition7.2providesameansoftrackingelongationsduringlift-offtesting.The10%toleranceinelongationsatspecificloadsofretensionedtendonsshouldincludetheeffectofdifferentialfriction(fromfullygreasedvs.coatedtendons)anderrorsattributedtocalibration,measurementprocedures,andequipment.RegulatoryPosition