Regulatory Guide 1.124
| ML13350A273 | |
| Person / Time | |
|---|---|
| Issue date: | 11/30/1976 |
| From: | NRC/OSD |
| To: | |
| References | |
| RG-1.124 | |
| Download: ML13350A273 (6) | |
.a..: ..... .-,- .... * .,. .:,U.S. NUCLEAR REGULATORY COMMISSIONNovember 1976REGULATORY GU`DEOFFICE OF STANDARDS DEVELOPMENTREGULATORY GUIDE 1.124DESIGN LIMITS AND LOADING COMBINATIONSFOR CLASS 1 LINEAR-TYPE COMPONENT SUPPORTS[*A. INTRODUCTIONGeneral Design Criterion 2, "Design Bases for Protec- NF-1122 and NA-2134 of Section Ill of the ASMEion Against Natural Phenomena," of Appendix A, Boiler and Pressure Vessel Code imply that the classifica-'General Design Criteria for Nuclear Power Plants," to tion of component supports slhould, as a minimum, be0 CFR Part 50, "Licensing of Production and Utiliza- the same as that of the supported componets. Thision Facilities," requires, in part, that the design bases should be considered as a requirement. This guideor structures, systems, and components important to delineates design limits and loading combinations, inafety reflect appropriate combinations of the effects of addition to supplerientary criteria, for ASME Class Iormal and accident conditions with the effects of linear-type componmi.t supports as defined by NF.1213atural phenomena such as earthquakes. The failure of of Section Ill. Snubbers uistalled for protection againstaembers designed to support safety-related components seismic or dynamic loadings of other origins are notould jeopardize the ability of the supported component addressed in this guide.o perform its safety function.*Pu sit ..-, on. .NF ad Ap e cioIThis guide delineates acceptable design limits and Subsction NF and Appendix XVII of Section IIIppropriate combinations of loadings associated waith ..-' mpernit the use of four methods for the design of Class Iormal operation, postulated accidents, and specified liniear-type component supports: linear elastic analysis.pismic events for the design of Class load rating, experimental stress analysis, and limitanentsupportas defined in' ..cio N-pe -analysis. For each method, the ASME Code delineatessupportss SOlno n;ubsection NFP of "-.. , .,.. .,ction IlI of the American Society of M.echanic., allowable stress or loading limits for various Codengincers (ASME) Boiler and Pressure Vessel Code. This, operating condition categories as defined by NF.3113 of....... aSection III so that these limits can be used in con-ide applies to light-water-cooled reactors. " " junction with the resultant loadings or stresses fromthe appropriate plant conditions. However, the Codc'sB. DISCUSSION..`. operating condition categories are simply componentLoad-be members 'd " support design limits; they are not necessarily related toLoa-baring em rsclasslif. ;as component sup-. dforts are essential to th safety of nuclear power fined plant conditions. Since the Code does notants sine theysrentain como nents" i paceaurig ther specify loading combinations, guidance is required toants since they retain companents In place during the provide a consistent basis for the design of compoitent)adings associated with normal, upset, and emergency supports..0!ant counuiions unuer. me suess of specifieu seismicents, thereby permitting system components to func-n properly. They also prevent excessive componentovement during the loadings associated with a faultedpnt condition combined with the specified seismicent, thus helping to mitigate the consequences ofstem damage. Component supports are deformationnsitivc because large deformations in thenm may signifi-atly change the stress distribution in the supportfstem and its supported components.The component supports considered in this guide arelocated within containment and are therefore assumedto be protected against loadings froin natural phenoin-ena or man-made hazards other than the specifiedseismic events. Thus only the specified seismic eventsneed to be considered in combination with the loadingsassociated with plant conditions to develop appropriateloading combinations.*0USNRC REGULATORY GUIDESPguleory Guide* are Issued to describe and make oawilahl to the publica rthod acceptaeble ta the NRC stall of Iemplamsnting traincc pPAs of thetlmmslaion'i requlmitlons. to delneate tachpiques used by the stilt in vlmu.n9 Sptecific probiem's a' co-'atuted accidents, ot to provide quldanel to eppli-Ito. iegutetor Guids are not substitutes tor reguletions. and con-,lianceh h then I ncot required, Methods and ssitmtas difsroot tnom triosi %tr cut Inguides will be ccuptaible it they provide a beasi Io, the lCndhg ruuUiaite tOisuafnceilOof inIotuence of a l or liercense theth 1",ent2 and suggestions fur improwqnients In theseu fl-de, are incouraoed-s 0,45', efl guides will be ivied., s to *ccuotnnousat coat.*'tnd it %tflct new information or eApartence. H'eot, or comrmtent on" ' -i-d within ebout two ninnih$s After its isoasnee. will Dc par.a eValtuating the naed tot an aur;V rov.vion.1. Power Reactors2. Rauaatch and Teot Reectot,3. Fuels and 6.1stetoe Factiltjia4. Environmental and S;tlni5. MuArletIl end Plant ProltctiunS. Products7. Tianipott iion1. Occupational Health9. Antitrust Reviewto. en.eralComments sho-id be sent to the Secretary of the Commlssion. U.S. NuclearRegulatory Commission, Washington, D.C. 20566. Attention: Docketing andServi.e Soction.The guides ere Issued In the following ten braid disialone:Corolea of pubilihed gvilet mme be obtained by written request irdlcatitg l1.4divisiort deuied to -no U S. Nuclear Reguiatosry Commistlon. Washington. D.C.ME&. Attention; D;rector. Office of Standards Develorment.7.1 !7ý-ý. 77 7.-". 74.--7rerý__r,i. ., :. ..
1. Design by Linear Elastic Analysisa. S, at Temperature. When the linear elastic anal-ysis method is used to design Class I linear-typecomponent supports, material properties are given byTables 1-13.1 and 1-13.3 in Appendix I of Section III andTables 3 and 4 in Code Case 1644-4. These tables listvalues for the minimum yield strength Sy at varioustemperatures but only room temperature values for theultimate tensile strength Su. At room temperature, Syvaries from 50% to 87% of Su for component su-portmaterials.Design limits derived from either material propertyalone may not be sufficient to provide a consistentdesign margin. This is recognized by Section HI, sinceXVU-221 l(a) of Section I1l defines the allowable stressin tension on a net section as the smaller value of 0.6Syand O.5Su. To alleviate the lack of defined values of S,at temperatures above room temperature and to providea safe design margin, an interim method is given in thisguide to obtain values of Su at temperature.While XVII-221 1(a) specifies allowable tensile stressin terms of both Sy and Su, the rest of XVII-2000specifies other allowable design limits in terms of Syonly. This does not maintain a consistent design marginfor those design limits related only to material proper-ties. Modifications similar to XVII-2211(a) should beemployed for all those design limits.b. Increase of Design Limits. While NF-3231.1(a),XVII-21 10(a), and F-1370(a) of Section III all permitthe increase of allowable stresses under various loadingconditions, XVII-21 10(b) limits the increase so thattwo-thirds of the critical buckling stress for compressionand compression flange members is not excee:. d, andthe increase allowed by NF-3231.1(a) is for stres- range.Critical buckling stresses with normal design margins arederived in XVII-2200 of Section Ill. Since bucklingprevents "shakedown" in a load-bearing member, XVII-2110(b) must be regarded as controlling. Also, bucklingis the result of the interaction of the configuration ofthe load-bearing member and its material properties (i.e.,elastic modulus E and minimum yield strength Sy).Because both of these material properties change withtemperature, the critical buckling stresses should becalculated with the values of E and Sy of the componentsupport material at temperature. Allowable design limitsfor bolted connections are derived from tensile and shearstress limits and their nonlinear interaction; they alsochange with the size of the bolt. For this reason, theincreases permitted by NF-3231.1, XVII-2110(a), andF-1370(a) of Section Ill are not directly applicable toallowable shear stresses and allowable stresses for boltsand bolted connections.The range of primary plus secondary stresses shouldbe limited to 2Sy but not more than Su to ensureshakedown. For many allowable stresses above the valueof 0.6S%.. the increase permitted by NF-323 1.1 (a) will beabove t'he value of 2Sx and will thus violate the normalshakedown range. A shakedown analysis is necessary tojustify the increase of stress above 2Sy or SU .For the linear elastic analysis method, F-1370(a) ofSection II permits increase of tension design limits forthe faulted operating condition category by a variablefactor which is the smaller value of i.2Sy/Ft or0.7S1,/Ft. Depending on whether the section consideredis a net section at pinholes in eyebars, pin-connectedplates, or built-up structural members, F1 may assumethe smaller value of 0.45Sy or 0.375Su (as recom-mended by this guide for a net section at pinholes, etc.)or the smaller value of 0.6Sy or O.5Su (for a net sectionwithout pinholes, etc.). Thus greater values of the factormay be obtained for sections at pinholes, which does notaccount for local stress and is not consistent withNF-3231.1 and XVII-2110(a) 6f Section I11. A pro-cedure to correct this factor is provided in this guide.2. Design by Load RatingWhen load-rating methods are used, Subsection NFand Appendix F of Section Ill do not provide a faultedcondition load rating. This guide provides an interimmethod for the determination of faulted condition loadrating.3. Design by Experimental Stress AnalysisWhile the collapse load for the experimental stressanalysis method is defined by 11-1430 in Appendix ii ofSection II, the design limits for experimental stressanalysis for various operating condition categories arenot delineated. This deficiency is remedied by themethod described in this guide.4. Large DeformationThe design of component supports is an integral partof the design of the system and its components. Acomplete and consistent design is possible only whensystem/component/component-support interaction isproperly considered. When all three are evaluated on anelastic basis, the interaction is usually valid becauseindividual deformations are small. However, if plasticanalysis methods are employed in the design process,large deformations that would result in substantiallydifferent stress distributions may occur.For the evaluation of the faulted operating conditioncategory, Appendix F of Section IlI permits the use ofplastic analysis methods in certain acceptable combina-tions for all three elements. These acceptable combina-tions are selected on the assumption that componentsupports are more deformation sensitive (i.e., theirdeformation in general will have a large effect on theStreSimdbutanimetfortheavoiS. IIinatibtakenornditicECCpropforcondideniSiAISCbuilt-steelindiscals amateisubstcequatmater6. DeSinload-bSectiofunctiDesignOnthsuppolthe strtions ithe de-7. DelDes,NF-311Vessel IEmetions thFaulassociatprobabi"" Nornin the c1.124-2 stress distribution in the systemSK Since large deformations always aononai( ( bution, care should be exercisedLary to ' analysis method is used in the )methodology combination. This isfor identifying buckling or instab0(a) of the change of geometry should benits for avoid erroneous results,ariable/Ft or 5. Function of Supported Systemrideredand its components).ffect the stress ditri-even if tht, plasticAppendix F-approvedespecially importantility problems wheretaken into account to'I:nnnectedassume.recom-les, etc.): sectionle factor:oes notnt withA pro-jide.:tion NFa faultedi interimtion load.tal stressidix II oftal stressiodes areby tka(In selecting design limits for different loading combi-.nations, the function of the supported system must betaken into account. To ensure that systems whosehormal safety-related function occurs during plant con-ditions other than normal or upset (e.g., the function ofECCS during faulted plant conditions) will operateproperly regardless of plant condition, the design limitsfor the design, normal, and upset plant operatingcondition categories of Subsection NF (which areidentical) should be used.Since Appendix XVII deriyed all equations fromAISC rules and many AISC.compressior equations havebuilt-in constants based on mechanical properties ofsteel at room temperature, to use these equationsindiscriminately for all NF and Code Case 1644 materi-als at all temperatures would not be prudent. Formaterials other than steel and working temperaturessubstantially different from room temperature, theseequations should be rederived with the appropriatematerial properties.6. Deformation LimitsSince component supports are deformation-sensitiveload-bearing elements, satisfying the design limits ofSection III will not automatically ensure their properfunction. Deformation limits, if specified by the CodeDesign Specification, may be the controlling criterion.On the other hand, if the function of a componentsupport is not required for a particular plant condition,the stresses or loads resulting from the loading combina-tions under that plant condition do not need to satisfythe design limits for that plant condition.7. DefinitionsDesign Condition. The loading condition defined byNF-3112 of Section III of the ASME Boiler and PressureVessel Code.Emergency Plant Condition. Those operating condi-tions that have a low probability of occurrence.refueling, and shutdown tither than upset, emergency, orfaulted plant conditions.Operating Basis Earthquake (OBE). As defined inAppendix A to 10 CFR Part 100.Operating Condition Categories. Categories of designlimits for component supports as defined by NF-3113 ofSection [i1 of the ASME Code.Plant Conditions. Operating conditions of the plantcategorized as normal, upset, emergency, and faultedplant conditions.Safe Shutdown Earthquake (SSE). As defined inAppendix A to 10 CFR Part 100.Specified Seismic Events. Operating Basis Earth-quake and Safe Shutdown Earthquake.System Mechanical Loadings. The static and dynamicloadings that are developed by the system operatingparameters, including deadweight, pressure, and othernon-self-limiting loadings, but excluding effects resultingfrom constraints of free-end movements and thermal andpeak stresses.Ultimate Tensile Strength. Material property basedon engineering stress-strain relationship.Upset Plant Conditions. Those deviations from thenormal plant condition that have a high probability ofoccurrence.C. REGULATORY POSITIONASME Codel Class I linear-type component supportsexcluding snubbers, which are not addressed herein,should be constructed to the rules of Subsection NF ofSection [If as supplemented by the following:21. The classification of component supports should,as a minimum, be the same as that of the supportedcomponents.2. Values of Su at a temperature t should beestimated by either Method I or Method 2 on an interimbasis until Section III includes such values.a. Method 1. This method applies to componentsupport materials whose values of ultimate strength Suat temperature have been tabulated by their manufac-turers in catalogs or other publications.lAmerican Society of Mechanical Engineers Boiler andPressure Vessel Code, Section Ill. Division 1, 1974 Edition,including the 1974 Winte; Addenda thereto.21i the function of a component support Is not requiredduring a plant condition, the design limits of the support for thatplant condition need not be satisfied, provided excessivedeflection o: failure of the support will not result in the loss offunction of any other safety-related system.ýgpal partnents. Aly whenaction isted on anI becauseif plasticIprocess,stantiallyconditionthe use ofcombina-.combina.urnj~entS*ie IerMLt on theFaulted Plant Condition. Those operating conditionsassociated with postulated events of extremely lowprobability.Normal Plant .condition. Those operating conditionsin the course of system startup, operation, hot standby,1.124-3 Su Sur .but not greater than SurwhereSu = ultimate tensile strength at temperature t to beused to determine the design limitsSur= ultimate tensile strength at room temperaturetabulated in Section IN, Appendix i, or CodeCase 1644-4Sý =ultimate tensile strength at temperature t tab-ulated by manufacturers in their catalogs orother publications* SLr .ultimate tensile strength at room temperaturetabulated by manufacturers in the same publi-cations.b. Method 2. This method applies to componentsupport materials whose values of ultimate tensilestrength at temperature have not been tabulated by theirmanufacturers in any catalog or publication.SU =Sur SSyrwhereSu = ultimate tensile strength at temperature t to beused to determine the design limitsSur = ultimate tensile strength at room temperaturetabulated in Section 111, Appendix I, or CodeCase 1644-4Sy = minimum yield strength at temperature t tab-ulated in Section III, Appendix I, or Code Case1644-4Syr minimum yield strength at room temperature,tabulated in Section III, Appendix 1, or CodeCase 1644-4.3. The design limits for component supports de-signed by linear elastic analysis for the design conditionand the normal or upset operating condition categories,3when these limits are related to Sy alone, should meetthe appropriate stress limits of Appendix XVII ofSection Ill but should not exceed the limit specifiedwhen the value of 5/6 Su is substituted for Sy. Examplesare shown .below in a and b. The bearing stress limitspecified by XVII-2461.2 should be modified by c(below).3Code operating condition categories only specify designlimits. They are not necessarily related to corresponding plantconditions.a. The tensile stress limit Ft for a net section asspecified in XVII-2211(a) of Section Ill should be thesmaller value of 0.6S, or O.5S at temperature. For netsections at pinholes in eye-bars, pin-connected plates, orbuilt-up structural members, F, as specified in XVII-2211(b) should be the smaller value of 0.45Sy or0.375SU at temperature.b. The shear stress limit F. for a gross section asspecified in XVII.2212 of Section 111 should be thesmaller value of OASy ir 0.33S, at temperature.c. The bearing stress limit F, on the projected areaof bolts in bearing-type connections as specified in XVf.U-2461.2 of Section I1l should be the smaller value of1.35Sy or 0.9Su at temperature, where Sy and S, arematerial properties of the connected part.Many Lmits and equations for compression strengthspecified in Sections XVII-2214, X'" 2224, XVII-2225,XVII-2240, and XVII-2260 have bi.-.: -in constants basedon Young's Modulus of 29,000 Ks: Ftr materials withYoung's Mlodulus at working temperatures substantiallydifferent from 29,000 Ksi, these constants sihould be re-derived with tie appropriate Young's Modulus unlessconservatism .of using these constants as specified can bedemonstrated.4. Component supports designed by linear elasticanalysis may increas, titeir design limits according to theprovisions of NF-3231.1(a), XVII-2110(a), andF-1370(a) of Section IlI. The increase of design limitsprovided by NF-3231.l(a) is for stress range. Theincrease of design limits provided by F-1370(a) for thefaulted operating condition category should be thesmaller factor of 2 or 1.167Su/Sy, if Su > 1.2S., or 1.Aif Su < 1.2Sy, where Sy and Su are component-supportmaterial properties at temperature.7)However, all increases [i.e., those allowed byNF-3231.1(a), XVII.2110(a), and F-1370(a)] shouldalways be limited by XVII-21 10(b) of Section III. Thecritical buckling strengths defined by XVII-21 10(b) ofSection III should be calculated using material propertiesat temperature. This increase of design limits does notapply to design limits for bolted connections and shearstresses. Any increase of design limits for bolted con-nections and shear stresses should be justified.If the increased design limit for stress range byNF-3231.1(a) is more than 2Sy or Su, it should belimited to the smaller value of 2Sy or Su unless it can bejustified by a shakedown analysis.S. Component supports subjected to the most ad-verse combination of the vibratory motion of the OBE1~~1.124-4-A and system mechanical loadings4 associated with eitherthe Code design condition or the normal or upset plantconditions should be designed within the followinglimits:5.6a. The stress limits of XVII-2000 of Section iflanf Regulatory Position 3 of this guide should not beexceeded for component supports designed by. the linearelastic analysis method. These stress limits may beincreased according to the provisions of NF-323 L.1(a) ofSection I11 and Regulatory Position 4 of this guide wheneffects resulting from constraints of free-end mechanicaland seismic displacements are added to the loadingcombination.b. The normal condition load rating or the upsetcondition load rating of NF-3262.3 of Section Ill shouldnot be exceeded for component supports designed bythe load-rating method.c. The lower bound collapse load determined byXVII-4200 adjusted according to the provision ofXVII-41 10(a) of Section III should not be exceeded forcomponent supports designed by the limit analysismethod.d. The collapse load determined by 11-1400 ofSection III divided by 1.7 should not be exceeded forcomponent supports designed by the experimental stressanalysis method.6. Component supports subjected to the most ad-verse combination of system mechanical loadings4 asso-ciated with the emergency plant condition should bedesigned within the following design limits except whentheir normal function is required during the emergencyplant condition (at which time Regulatory Position 8applies):S.6a. The stress limits of XVII-2000 of Section IlIand Regulatory Positions 3 and 4, increased according tothe provisions of XVII-2110(a) of Section Ill andRegulatory Position 4 of this guide, should not beexceeded for component supports designed by the linearelastic analysis method.* 4System mechanical loadings include all non-self-Limitingloadings and do not include loadings resulting from constraintsof frec-end displacements and thermal or peak stresses.S$ince component supports are deforma'ion sensitive in theperformance of their service requirements, satisfying thesecriteria does not ensure that their functional requirements will6e futrlibd. Any deformation limits specified by the designspecification may be controlling and should be satisfied.6Since the design of component supports is an integral partof the design of the system and the design of the component, thedesigner must make sure that methods used for the analysis ofthe system, component, and component support are compatible(see Table F-1322.2-1 in Appendix F of Section ill). Largedeformations in the system or compohnnts should be consideredin the design of component supports.b. The emergency condition load rating ofNF-3262.3 of Section [it should not be exceeded forcomponent supports designed by the load-ratingmethod.c. The lower bound collapse load determined byXVII-4200 adjusted according to the provision ofXV 1-4110(a) of Section Ill should not be exceeded forcomponent supports designed by the limit analysismethod.d. The collapse load detcrmined by 11-1400 ofSection III divided by 1.3 should not be exceeded forcomponent supports designed by the experimental stressanalysis method.7. Component supports subjected to the most ad-verse combination of the vibratory motion of &S-E andsystem mechanical loadings4 associated simultaneouslywith the faulted plant condition and the normal plantcondition should be designed within the following designlimits except when their normal function is requiredduring the faulted plant condition (at which timeRegulatory Position g applies):3.5.,6a. The stress limits of XVII-2000of Section IIIand Regulatory Position 3 of this guide, increasedaccording to the provisions of F-1370(a) of Section IIIand Regulatory Position 4 of this guide, should not beexceeded for component supports designed by the linearelastic analysis method.b. The smaller value of T.L. X 2S/S, orT.L. X 0.TSu/Su should not be exceeded, where T.L., S,and S, are defined according to NF-3262.1 of Sectionl1l, and Su is the minimum ultimate tensile strength ofthe material at service temperature for componentsupports designed by the load-rating method.c. The lower bound collapse load determined byXVII-4200 adjusted according to the provision ofF-1370(b) of Section III should not be exceeded forcomponent supports designed by the limit analysismethod.d. The collapse load determined by 11-1400 ad-justed according to the provision of F-1370(b) ofSection III should not be exceeded for componentsupports designed by the experimental stress analysismethod.8. Component supports whose normal function isrequired during an emergency or faulted plant conditionand that are subjected to loading combinations describedin Regulatory Positions 6 and 7 should be designedwithin the design limits described in Regulatory Position5 or other justifiable design limits.1.124-5 D. IMPLEMENTATIONThe purpose of this section is t,, provide guidance toapplicants and liceiisces regarding tile NRC staff's plansfor using this regulatory guide.Except in those cases in which the applicant proposesan acceptable alternative method for complying with thespecified porlions of the Commission's regulations, themethod described herein will be used in the evaluationof submittals for construction permit applications dock-eted after JAly 1, 1977. If an applicant wishes to usethis regulatory guide in developing submittals forconstruction permit applications docketed on or beforeJuly 1. 1977, the pertinent portions of the applicationwill be evaluated on the basis of this guide.N.)I~1.124-6