ML18004A007

2018/01/02 Seabrook La -

ML18004A007
Person / Time
Site:	Seabrook
Issue date:	01/02/2018
From:	NRC
To:	Division of Operating Reactor Licensing
References
17-953-02-LA-BD01
Download: ML18004A007 (14)

Text

1SeabrookLANPEm ResourceFrom:SeabrookLAHearingFile ResourceSent:Tuesday, January 02, 2018 2:42 PMTo:SeabrookLANPEm ResourceAttachments:170444-L-001 Rev. 0.pdf Hearing Identifier: Seabrook_LA_NonPublic Email Number: 1341 Mail Envelope Properties (8d5e0168125e4699b25984c1e541eb8d)

Subject:

Sent Date: 1/2/2018 2:41:42 PM Received Date: 1/2/2018 2:41:52 PM From: SeabrookLAHearingFile Resource Created By: SeabrookLAHearingFile.Resource@nrc.gov Recipients: "SeabrookLANPEm Resource" <SeabrookLANPEm.Resource@nrc.gov>

Tracking Status: None Post Office: HQPWMSMRS01.nrc.gov Files Size Date & Time MESSAGE 3 1/2/2018 2:41:52 PM 170444-L-001 Rev. 0.pdf 619783 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

6 November2017Mr. EdwardCarleyEngineering Supervisor - License RenewalNextEra Energy Seabrook, LLC.

P.O. Box 300, Lafayette RoadSeabrook, NH 03874Project170444 - License Amendment Request & NRC Review Support, NextEra Energy Seabrook Station,Seabrook,NHReference - Evaluation of Containment Enclosure VentilationArea (CEVA), Calculation160268-CA-05(FP101122),22 March 2017 Document Number: 170444-L-001

DearMr. Carley:

The structural evaluation of the Containment Enclosure Ventilation Area (CEVA), referenced above, showed that its north wall between EL +3 and +19 ft was bowed outward with a maximum out-of-plumbness of 1.25 in., measured during SGH field observation in February 2017. The referenced calculation showed that the wall can move by anadditional 25% (reaching to 1.5 in.

at the point of maximum bowing) before conducting a more robust analysis or repairing the wall becomes necessary. The bowing limit of 1.5 in. was calculatedconservatively in the referenced calculation by neglecting the compression reinforcement in calculating themoment-curvaturebehavior ofthe wall. The limit of bowing is recalculated as shown in Attachment A consideringthe compression reinforcement in the moment-curvature calculation, and including the effects of upward vertical movement of CEVA.The upward movement of CEVA can imposevertical tension inthe north wall of CEVA. Accordingly, moment-curvature relationships are calculated at different levels of tension.At each level of axial force, a limiting curvature is determined to avoid unacceptable behavior. As explained in Attachment A, the curvature value of 0.003 1/in. corresponds either to the buckling of compression reinforcement (for cases with low level of axial tension) or rupture of tension reinforcement (for cases with high level of axial tension). Conservatively, 90% of this curvature value (0.0027 1/in.) is selected for computing the maximum bowing that the wall can resist. The computed moment-curvature relationships are assigned to afinite element model of the wall, and nonlinear analyses are performed to determinethe lateral displacement at which the curvature of the wall at the point of maximum bowing reaches the limiting curvature. Figure A2 in AttachmentA shows that 2 in. of lateral wall deformation induces curvature of0.00271/in.in the wall with alow level of axial force, while the same displacement induces curvature of 0.0023 1/in.

in the wall with ahigh level of axial tension.Therefore, the wall can resist alateral bowing of 2in.

Mr. Edward Carley - Project170444 6 November2017Document No. 170444-L-001Revision 0 before buckling or rupture of the vertical reinforcement will occur(with 10% margin), andit is recommended that the wall beretrofittedprior to itexperiencing 2 in. of bowing. Thesite visit report (170444-SVR-01-R0, FP101192-00) for the recent measurements indicates that the wall moved outwardsince the previous measurements;bulging has increased to 1-7/16 in. Additionally, at alocalized area, hammer sounding indicated portions of the concrete coverpotentiallysusceptible to separation, especially atareas with larger horizontal cracks. Therefore, sensitive equipment or processes shouldbe protected againstpossible fallingpieces of concrete cover fromthis wall before it is retrofitted.Sincerely yours,Said BolourchiMichael Mudlock, P.E.Senior PrincipalSenior Project ManagerNH License No. 14808I:\BOS\Projects\2017\170444.00-LARS\Workspace\CEVA North Wall\170444-L-001 Rev. 0.docx PROJECTNO:170444DATE:Nov2017CLIENT:NextEraEnergySeabrookBY:MR.M.Gargari

SUBJECT:

EvaluationofAdditionalDisplacementfortheNorthWallofCEVAVERIFIER:I.BaigATTACHMENTAMOMENTCURVATURERELATIONFORTHECEVANORTHWALLA1.REVISIONHISTORYRevision0:Initialdocument.A2.OBJECTIVEOFCALCULATIONTheobjectiveofthiscalculationistocomputemoment-curvaturediagramsforthenorthwallofContainmentEnclosureVentilationArea(CEVA)structuresubjectedtodifferenttensileforce.A3.RESULTSANDCONCLUSIONSFigureA2presentsmoment-curvaturediagramforthewallsectionsubjectedtodifferenttensileforce.Ascanbeseenfromthefigure,byincreasingthemagnitudeoftensileforce,thefailuremodechangesfrom compressiverebarbucklingtotensilerebarrupture.Forallcases,thepointofseveredamageinitiation approximatelycorrespondstocurvaturevalueof0.003(1/in.).Accordingly,thispointisselectedasalimitingcurvatureandthewallisallowedtodeformuptothiscurvature.FigureA3providesacomparisonbetweentwocases,onewithaccountingfortheeffectofcompressiverebarsandtheotheronewithoutconsideringthecompressiverebars.Ascanbeseenfromthefigure,includingtheresistanceofferedbycompressivereinforcementdoesnotaffecttheultimatecapacitynoticeably,however,itincreasestheductilityofasection.A4.DESIGNDATA/CRITERIASeeSection4ofthecalculationmainbody(160268-CA-05Rev.0).A5.ASSUMPTIONSA5.1JustifiedassumptionsTherearenojustifiedassumptions.A5.2UnverifiedassumptionsTherearenounverifiedassumptions.AttachmentA-A Revision0 A6.METHODOLOGYTocalculatethemoment-curvaturediagrams,sectionalanalysisbasedonfibersectionmethodforintegratingoverthecrosssectionisused.Inthismethod,thecrosssectionisdiscretizedintofibers(orlayerssubjectedtounidirectionalbending),andanappropriatematerialmodelisassignedtoeachfiber.FigureA1demonstratesatypicalfibersectiondiscretization.Inthisstudy,eachsectionisdiscretizedinto20fibers/layers.TheconcretematerialisrepresentedbyKentandPark[A5]modelincompressionand Steven'sexponentialsofteningmodelintension[A3].Reinforcingsteelbarsaremodeledusingelastic perfectlyplasticmaterialwithstraincutoffof0.007intensionandaccountingforinelasticbucklingmodelofKashanietal.[A4]incompression.Moment-curvaturediagramsarethencalculatedforaxialtensionof0,10,30and60kips.Eachpointisderivedbyselectinganaxialforce,andthenchangingcurvaturevalueandcalculatingthemoment.FigureA2presentsthecomputedmoment-curvaturediagrams.Anadditionalstudyisconductedtoshowtheeffectofincludingorexcludingcompressivereinforcement.Thestudyshowsaccountingfortheeffectofcompressiverebarsincreasestheductilityofamemberas presentedinFigureA3;therefore,themembercanaccommodatemoredisplacement.A7.REFERENCES[A1]SimpsonGumpertz&HegerInc.,EvaluationofContainmentEnclosureVentilationArea,160268-CD-05Rev.1,Waltham,MA,Mar.2017.[A2]UnitedEngineers&ConstructorsInc.,SeabrookStationStructuralDesignDrawings.

[A3]YuanLu,andMariosPanagiotou."Three-dimensionalcyclicbeam-trussmodelfornonplanarreinforcedconcretewalls."JournalofStructuralEngineering,2013,140(3):04013071.[A4]MohammadM.Kashani,LauraN.Lowes,AdamJ.Crewe,NicholasA.Alexander,Phenomenologicalhystereticmodelforcorrodedreinforcingbarsincludinginelasticbucklingand low-cyclefatiguedegradation,ComputerandStructures,156(1),58-71,2015.[A5]Dudley.C.Kent,andRobertPark,Flexuralmemberswithconfinedconcrete,ASCEJournalofStructuralDivision,97(ST7),1969-1990,1971.AttachmentA-A Revision0 A8.COMPUTATIONGeometryRebardiameterdb1.128inReinforcementratio21in212in24in6.944103ConcreteMaterialModelCompressivestrengthofconcretefc3ksiKent&ParkModelStrainatPeakcompressivestrengthco0.002Strainat50%compressivestrength50u30.002fcpsifcpsi10004.5103ModelparameterZ0.550uco200Residualcompressivestrengthfc.resfc0.02575psiSteven'sModelYoung'smodulusofconcreteEc3120ksiTensilestrengthofconcreteft5fcpsi273.861psiStrainatcrackingcrftEc8.778105ModelparameterthatcontrolsresidualM75mmdb0.018Modelparameterthatcontrolssofteningslopet540M4.005103MATconc()minfc.resfc1Zcocoiffc2coco2co0ifEc0crifft1M()etcrMcrifConstitutivemodelforconcreteAttachmentA-A Revision0 0.0151030420StrainStress(ksi)MATconccksicSteelMaterialModelYieldstrengthofsteelfy60ksiYoung'smodulusofsteelEs29000ksiYieldstrainyfyEs2.069103Rupturestrainsr0.07AccountforbucklingBuckling1Put0toignore,put1toconsiderKashaniModel(buckling)Unbracedlength/DiameterLD15Slendernessratiopfy100MPaLD30.509Modelparameters14.572p74.4365.0572318.4e0.071p36.495star3.75fyLD15ksiAttachmentA-A Revision0 ConstitutivemodelforsteelMATsteel()fyBuckling0=ifstarfystare12yyotherwiseyiffyysrif0srifEsotherwise0.0500.0550050StrainStress(ksi)MATsteelsksisConcreteFibersWidthoffibersb12inRef.2,2ftthickwallTotalthicknessorheighth24inNumberoffibersConcNum20HeightoffibersConcHhConcNum1.2inConcretefibercoordinatesConcyansih2ConcH2i1()ConcHi1ConcNumforansConcretefiberstrainConcoansioConcyii1ConcNumforansAttachmentA-A Revision0 ConcretefiberstressConcoansiMATconcConcoii1ConcNumforansConcretefiberforceConcFoansiConcoibConcHi1ConcNumforansReinforcement/SteelfibersDepthtoreinforcementd20.5inRef.2,2ftthickwallAreaoftensilereinforcement(#9@12in.)As1in2Numberofreinforcementinrow,e.g.equalto2fortensileandcompressiveSteelNum2DepthtoreinforcementfiberSteely1dh28.5inSteely2dh28.5inAreaofreinforcementfiberSteelAs1As1in2SteelAs2As1in2SteelfiberstrainSteeloansioSteelyii1SteelNumforansSteelfiberstressSteeloansiMATsteelSteeloii1SteelNumforansSteelfiberforceSteelFoansiSteeloiSteelAsii1SteelNumforansAttachmentA-A Revision0 AxialEquilibriumForceoans10ans1ans1ConcFoii1ConcNumforans20ans2ans2SteelFoii1SteelNumforansans1ans2MomentEquilibriumMomentoans10ans1ans11ConcFoiConcyii1ConcNumforans20ans2ans21SteelFoiSteelyii1SteelNumforansans1ans2SolutionKnownparametersAxialforceP60kipIterationCurvature0.0031inSolveforstrainatcentroidAxialstrainatcentroid(initialguess)xo0.03RequiresiterationAxialforceequilibriumfx()Forcex()Pcentrootfxoxo0.027SectionalforcesForcecent60kipMomentcent48.079kipftAttachmentA-A Revision0 StressandstraininconcreteandsteelSteelfiberstressandstrainRebarSteelcent0.0521.266103RebarSteelcent6036.723ksiSteelFcent6036.723kipConcreteyConcyConcretefiberstressandstrainConcreteConccentConcreteConccentMaximumcompressivestraininconcretemax.compRebar2Rebar1Steely2Steely1h2Steely1Rebar19.234103AttachmentA-A Revision0 A9.TABLESTherearenotables.A10.FIGURESFigureA1:SchematicrepresentationoffibersectionmethodFigureA2:Moment-curvaturediagramsfordifferentaxialforceAttachmentA-A Revision0 FigureA3:Moment-curvaturediagramconsideringtheeffectofincludingorexcludingcompressiverebarsAttachmentA-A-10-Revision0