Regulatory Guide 1.124: Difference between revisions

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{{#Wiki_filter:.a..: ..... .-,- .... * .,. .:, U.S. NUCLEAR REGULATORY  
{{#Wiki_filter:. : ..... . -,-   .... * .,. :..-.*.- .:,
COMMISSION
            .a.
November 1976 REGULATORY  
 
GU`DE OFFICE OF STANDARDS  
U.S. NUCLEAR REGULATORY COMMISSION                                                                                                                                           November 1976 REGULATORY GU`DE
DEVELOPMENT
              OFFICE OF STANDARDS DEVELOPMENT
REGULATORY  
                                                                                                      REGULATORY GUIDE 1.124 DESIGN LIMITS AND LOADING COMBINATIONS
GUIDE 1.124 DESIGN LIMITS AND LOADING COMBINATIONS
                                                                            FOR CLASS 1 LINEAR-TYPE COMPONENT SUPPORTS
FOR CLASS 1 LINEAR-TYPE  
COMPONENT  
SUPPORTS[*


==A. INTRODUCTION==
==A. INTRODUCTION==
General Design Criterion  
General Design Criterion 2, "Design Bases for Protec-                                                           NF-1122 and NA-2134 of Section Ill of the ASME
2, "Design Bases for Protec- NF-1122 and NA-2134 of Section Ill of the ASME ion Against Natural Phenomena," of Appendix A, Boiler and Pressure Vessel Code imply that the classifica-
                ion 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, be 0 CFR Part 50, "Licensing of Production and Utiliza- the same as that of the supported componets.
              'General Design Criteria for Nuclear Power Plants," to                                                             tion of component supports slhould, as a minimum, be
                0 CFR Part 50, "Licensing of Production and Utiliza-                                                             the same as that of the supported componets. This ion Facilities," requires, in part, that the design bases
              [                                                                                                                  should be considered                as a requirement. This guide or structures, systems, and components important to                                                                delineates design limits and loading combinations, in afety reflect appropriate combinations of the effects of                                                          addition to supplerientary criteria, for ASME Class I
                ormal and accident conditions with the effects of                                                                linear-type componmi.t supports as defined by NF.1213 atural phenomena such as earthquakes. The failure of                                                            of Section Ill. Snubbers uistalled for protection against aembers designed to support safety-related components                                                              seismic or dynamic loadings of other origins are not ould jeopardize the ability of the supported component                                                            addressed in this guide.


This ion Facilities," requires, in part, that the design bases should be considered as a requirement.
o perform its safety function.


This guide or structures, systems, and components important to delineates design limits and loading combinations, in afety reflect appropriate combinations of the effects of addition to supplerientary criteria, for ASME Class I ormal and accident conditions with the effects of linear-type componmi.t supports as defined by NF.1213 atural phenomena such as earthquakes.
*Pu                                                                                  ,..-
                                                                                                                                              sit on.. NF ad Ap e dx.V*ofS cioI
                      This guide delineates acceptable design limits and                                                               Subsction NF and Appendix XVII of Section III
                ppropriate combinations of loadings associated waith ..-'                                                              mpernitthe use of four methods for the design of Class I
                ormal operation, postulated accidents,                                                and   specified          liniear-type       component supports: linear elastic analysis.


The failure of of Section Ill. Snubbers uistalled for protection against aembers designed to support safety-related components seismic or dynamic loadings of other origins are not ould jeopardize the ability of the supported component addressed in this guide.o perform its safety function.*Pu sit ..-, on. .NF ad Ap e cioI This guide delineates acceptable design limits and Subsction NF and Appendix XVII of Section III ppropriate combinations of loadings associated waith ..-' mpernit the use of four methods for the design of Class I ormal operation, postulated accidents, and specified liniear-type component supports:
.0          pismic
linear elastic analysis.pismic events for the design of Class load rating, experimental stress analysis, and limit anentsupportas defined in' ..cio N-pe -analysis.
                *omponn events anentsupportas for supportss defined in'
 
                  ,ction IlI of the American Society of M.echanic.,
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 Code ngincers (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 from the appropriate plant conditions.
                                                                    the     design     of   Class
 
                                                                                                ..
However, the Codc's  
                                                                                                SOlno n;ubsection  cio N-pe NFP of load     rating,     experimental stress analysis, and limit
                                                                                                                            "-..-analysis. For each method,         ,   . the,.. ASME Code delineates allowable stress or loading limits for various Code
                                                                                                                                                                                                              .
                  ngincers (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 from the appropriate plant conditions. However, the Codc's  


==B. DISCUSSION==
==B. DISCUSSION==
..`.  
..`.                                                 operating condition categories are simply component Load-be Loa-baring members                     em rsclasslif.          'd ;as "component sup-.                    support df          design limits; they are not necessarily related to
operating condition categories are simply component Load-be members 'd " support design limits; they are not necessarily related to Loa-baring em rsclasslif.
              !    orts are essential to th safety of nuclear power ants sine theysrentain como nents"i paceaurig ther ants since they retain companents In place during the
                  )adings associated with normal, upset, and emergency ant counuiions unuer. me suess of specifieu seismic ents, thereby permitting system components to func- n properly. They also prevent excessive component ovement              during combined    the loadings            associated        with a seismic faulted fined plant conditions. Since the Code does not specify loading combinations, guidance is required to provide a consistent basis for the design of compoitent supports.


;as component sup-. df orts are essential to th safety of nuclear power fined plant conditions.
The component supports considered in this guide are located within containment and are therefore assumed pnt            condition                                      with      the specified to be protected against loadings froin natural phenoin- ent, thus helping to mitigate the consequences of                                                              ena or man-made hazards other than the specified stem damage. Component supports are deformation                                                                seismic events. Thus only the specified seismic events nsitivc because large deformations in thenm may signifi-                                                      need to be considered in combination with the loadings atly change the stress distribution in the support                                                              associated with plant conditions to develop appropriate fstem and its supported components.                                                                              loading combinations.


Since the Code does not ants sine theysrentain como nents" i paceaurig ther specify loading combinations, guidance is required to ants 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 seismic ents, thereby permitting system components to func-n properly.
USNRC REGULATORY GUIDES                                                              Comments sho-id be sent to the Secretary of the Commlssion. U.S. Nuclear Regulatory Commission, Washington, D.C. 20566. Attention: Docketing and Pguleory Guide* are Issued to describe and make oawilahl to the public Servi.e Soction.


They also prevent excessive component ovement during the loadings associated with a faulted pnt condition combined with the specified seismic ent, thus helping to mitigate the consequences of stem damage. Component supports are deformation nsitivc because large deformations in thenm may signifi-atly change the stress distribution in the support fstem and its supported components.
a rthod acceptaeble ta the NRC stall of Iemplamsnting traincc pPAs of the tlmmslaion'i requlmitlons. to delneate tachpiques used by the stilt in vlmu.


The component supports considered in this guide are located within containment and are therefore assumed to be protected against loadings froin natural phenoin-ena or man-made hazards other than the specified seismic events. Thus only the specified seismic events need to be considered in combination with the loadings associated with plant conditions to develop appropriate loading combinations.
The guides ere Issued In the following ten braid disialone:
                  n9 Sptecific probiem's a' co-'atuted accidents, ot to provide quldanel to eppli- Ito. iegutetor            Guids are not substitutes tor reguletions. and con-,liance h then I ncot required, Methods and ssitmtas difsroot tnom triosi %trcut In                                    1. Power Reactors                      S. Products
                                                                                                                                  2. Rauaatch and Teot Reectot,         


*0 USNRC REGULATORY
===7. Tianipottiion===
GUIDES Pguleory Guide* are Issued to describe and make oawilahl to the public a rthod acceptaeble ta the NRC stall of Iemplamsnting traincc pPAs of the tlmmslaion'i requlmitlons.
  *0
                    guides will be ccuptaible it they provide a beasi Io, the lCndhg ruuUiaite tO
                    isuafnceilOof        inIotuence of a              orl    liercense    theth aomn*,ssin.,.
                                                                                                                                  3. Fuels and 6.1stetoe Factiltjia     


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.
===1. Occupational Health===
                                                                                                                                  4. Environmental and S;tlni           


and con-,liance h h then I ncot required, Methods and ssitmtas difsroot tnom triosi %tr cut In guides will be ccuptaible it they provide a beasi Io, the lCndhg ruuUiaite tO isuafnceilOof inIotuence of a l or liercense theth
===9. Antitrust Review===
1",ent2 and suggestions fur improwqnients In theseu fl-de, are incouraoed-s 0,4 5', efl guides will be ivied., s to *ccuotnnousat coat.*'tnd it %tflct new information or eApartence.
                    1",ent2 and suggestions fur improwqnients In theseu fl-de, are incouraoed                                     5. MuArletIl end Plant Proltctiun      to. en.eral
                        ',-s 5    0,4 guides will be ivied.,
                                    efl                                        s pr*pproittri.    to *ccuotnnousat coat.


H'eot, or comrmtent on" ' -i-d within ebout two ninnih$s After its isoasnee.
*'tnd it %tflct      new information or eApartence. H'eot,                   or comrmtent on           Coroleaof pubilihed gvilet mme be obtained by written request irdlcatitg l1.4
                                  "'     -i-d within ebout two ninnih$s After its isoasnee. will Dc par.


will Dc par.a eValtuating the naed tot an aur;V rov.vion.1. Power Reactors 2. Rauaatch and Teot Reectot, 3. Fuels and 6.1stetoe Factiltjia
a eValtuating the naed tot an aur;Vrov.vion.                                               divisiort deuied to -no U S. Nuclear Reguiatosry Commistlon. Washington. D.C.
4. Environmental and S;tlni 5. MuArletIl end Plant Proltctiun S. Products 7. Tianipott iion 1. Occupational Health 9. Antitrust Review to. en.eral Comments sho-id be sent to the Secretary of the Commlssion.


U.S. Nuclear Regulatory Commission, Washington, D.C. 20566. Attention:
ME&. Attention; D;rector. Office of Standards Develorment.
Docketing and Servi.e Soction.The guides ere Issued In the following ten braid disialone:
Corolea of pubilihed gvilet mme be obtained by written request irdlcatitg l1.4 divisiort deuied to -no U S. Nuclear Reguiatosry Commistlon.


Washington.
--                        7rerý__r,                                                                        7.1 !7ý-ý.
                                                                                                                                                                                                          77 7.-".74.


D.C.ME&. Attention;
i. ., :. ..
D;rector.


Office of Standards Develorment.
1. Design by Linear Elastic Analysis                          shakedown. For many allowable stresses above the value            Stre of 0.6S%.. the increase permitted by NF-323 1.1 (a) will be      Simd a. S, at Temperature. When the linear elastic anal-        above t'he value of 2Sx and will thus violate the normal          but ysis method is used to design Class I linear-type              shakedown range. A shakedown analysis is necessary to            ani component supports, material properties are given by            justify the increase of stress above 2Sy or SU .                  met Tables 1-13.1 and 1-13.3 in Appendix I of Section III and                                                                        for Tables 3 and 4 in Code Case 1644-4. These tables list              For the linear elastic analysis method, F-1370(a) of          the values for the minimum yield strength Sy at various            Section II permits increase of tension design limits for          avoi temperatures but only room temperature values for the          the faulted operating condition category by a variable ultimate tensile strength Su. At room temperature, Sy          factor which is the smaller value of i.2Sy/Ft or                  S. I
varies from 50% to 87% of Su for component su-port              0.7S1,/Ft. Depending on whether the section considered materials.                                                      is a net section at pinholes in eyebars, pin-connected                Ii plates, or built-up structural members, F1 may assume            natib Design limits derived from either material property        the smaller value of 0.45Sy or 0 .3 7 5 Su (as recom-            take alone may not be sufficient to provide a consistent            mended by this guide for a net section at pinholes, etc.)        norn design margin. This is recognized by Section HI, since          or the smaller value of 0.6Sy or O.5Su (for a net section        ditic XVU-221 l(a) of Section I1l defines the allowable stress        without pinholes, etc.). Thus greater values of the factor        ECC
in tension on a net section as the smaller value of 0.6Sy      may be obtained for sections at pinholes, which does not        prop and O.5Su. To alleviate the lack of defined values of S,        account for local stress and is not consistent with              for at temperatures above room temperature and to provide          NF-3231.1 and XVII-2110(a) 6f Section I11. A pro-                cond a safe design margin, an interim method is given in this        cedure to correct this factor is provided in this guide.        ideni guide to obtain values of Su at temperature.


7.1 !7ý-ý. 77 7.-". 74.--7rerý__r, i. ., :. ..
2. Design by Load Rating                                            Si While XVII-221 1(a) specifies allowable tensile stress                                                                      AISC
1. Design by Linear Elastic Analysis a. S, at Temperature.
in terms of both Sy and Su, the rest of XVII-2000                  When load-rating methods are used, Subsection NF              built- specifies other allowable design limits in terms of Sy          and Appendix F of Section Ill do not provide a faulted          steel only. This does not maintain a consistent design margin          condition load rating. This guide provides an interim            indisc for those design limits related only to material proper-       method for the determination of faulted condition load          als a ties. Modifications similar to XVII-2211(a) should be          rating.                                                           matei employed for all those design limit


When the linear elastic anal-ysis method is used to design Class I linear-type component supports, material properties are given by Tables 1-13.1 and 1-13.3 in Appendix I of Section III and Tables 3 and 4 in Code Case 1644-4. These tables list values for the minimum yield strength Sy at various temperatures but only room temperature values for the ultimate tensile strength Su. At room temperature, Sy varies from 50% to 87% of Su for component su-port materials.
====s. substc====
                                                                3. Design by Experimental Stress Analysis                        equat b. Increase of Design Limits. While NF-3231.1(a),                                                                          mater XVII-21 10(a), and F-1370(a) of Section III all permit              While the collapse load for the experimental stress the increase of allowable stresses under various loading        analysis method is defined by 11-1430 in Appendix ii of          6. De conditions, XVII-21 10(b) limits the increase so that          Section II, the design limits for experimental stress two-thirds of the critical buckling stress for compression      analysis for various operating condition categories are              Sin and compression flange members is not excee:. d, and            not delineated. This deficiency is remedied by the              load-b the increase allowed by NF-3231.1(a) is for stres- range.       method described in this guide.                                  Sectio Critical buckling stresses with normal design margins are                                                                        functi derived in XVII-2200 of Section Ill. Since buckling            4. Large Deformation                                            Design prevents "shakedown" in a load-bearing member, XVII-                                                                             Onth
2110(b) must be regarded as controlling. Also, buckling            The design of component supports is an integral part        suppol is the result of the interaction of the configuration of        of the design of the system and its components. A                the str the load-bearing member and its material properties (i.e.,      complete and consistent design is possible only when            tions i elastic modulus E and minimum yield strength Sy).              system/component/component-support interaction is              the de- Because both of these material properties change with          properly considered. When all three are evaluated on an temperature, the critical buckling stresses should be          elastic basis, the interaction is usually valid because        7. Del calculated with the values of E and Sy of the component        individual deformations are small. However, if plastic support material at temperature. Allowable design limits        analysis methods are employed in the design process,                 Des, for bolted connections are derived from tensile and shear      large deformations that would result in substantially          NF-311 stress limits and their nonlinear interaction; they also        different stress distributions may occu


Design limits derived from either material property alone may not be sufficient to provide a consistent design margin. This is recognized by Section HI, since XVU-221 l(a) of Section I1l defines the allowable stress in tension on a net section as the smaller value of 0.6Sy and O.5Su. To alleviate the lack of defined values of S, at temperatures above room temperature and to provide a safe design margin, an interim method is given in this guide to obtain values of Su at temperature.
====r. Vessel I====
change with the size of the bolt. For this reason, the increases permitted by NF-3231.1, XVII-2110(a), and                For the evaluation of the faulted operating condition            Eme F-1370(a) of Section Ill are not directly applicable to                                                                        tions th category, Appendix F of Section IlI permits the use of allowable shear stresses and allowable stresses for bolts        plastic analysis methods in certain acceptable combina-            Faul and bolted connections.                                        tions for all three elements. These acceptable combina-        associat tions are selected on the assumption that component            probabi The range of primary plus secondary stresses should        supports are more deformation sensitive (i.e., their be limited to 2Sy but not more than Su to ensure                deformation in general will have a large effect on the      ""    Norn in the c
                                                          1.124-2


While XVII-221 1(a) specifies allowable tensile stress in terms of both Sy and Su, the rest of XVII-2000 specifies other allowable design limits in terms of Sy only. This does not maintain a consistent design margin for those design limits related only to material proper-ties. Modifications similar to XVII-2211(a)  
stress distribution in the system and its components).         refueling, and shutdown tither than upset, emergency, or SK  Since large deformations always affect the stress ditri-       faulted plant conditions.
should be employed 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 permit the increase of allowable stresses under various loading conditions, XVII-21 10(b) limits the increase so that two-thirds of the critical buckling stress for compression and compression flange members is not excee:. d, and the increase allowed by NF-3231.1(a)
is for stres- range.Critical buckling stresses with normal design margins are derived in XVII-2200
of Section Ill. Since buckling prevents "shakedown" in a load-bearing member, XVII-2110(b) must be regarded as controlling.


Also, buckling is the result of the interaction of the configuration of the load-bearing member and its material properties (i.e., elastic modulus E and minimum yield strength Sy).Because both of these material properties change with temperature, the critical buckling stresses should be calculated with the values of E and Sy of the component support material at temperature.
ononai(    (  bution, care should be exercised even if tht, plastic Lary to      '  analysis method is used in the )Appendix F-approved Operating Appendix    A toBasis
                                                                                                        10 CFR  Part 100. (OBE). As defined in Earthquake methodology combination. This is especially important for identifying buckling or instab ility problems where            Operating Condition Categorie


Allowable design limits for bolted connections are derived from tensile and shear stress limits and their nonlinear interaction;
====s. Categories of design====
they also change with the size of the bolt. For this reason, the increases permitted by NF-3231.1, XVII-2110(a), and F-1370(a)
  'I0(a) of          the change of geometry should be taken into account to          limits for component supports as defined by NF-3113 of nits for        avoid erroneous results,                                       Section [i1 of the ASME Code.
of Section Ill are not directly applicable to allowable shear stresses and allowable stresses for bolts and bolted connections.


The range of primary plus secondary stresses should be limited to 2Sy but not more than Su to ensure shakedown.
:n ariable
                    5. Function of Supported System                                    Plant Conditions. Operating conditions of the plant
    /Ft or                                                                          categorized as normal, upset, emergency, and faulted ridered In selecting design limits for different loading combi-      plant conditions.


For many allowable stresses above the value of 0.6S%.. the increase permitted by NF-323 1.1 (a) will be above t'he value of 2Sx and will thus violate the normal shakedown range. A shakedown analysis is necessary to justify the increase of stress above 2Sy or SU .For the linear elastic analysis method, F-1370(a)  
nnected assume.         .nations, the function of the supported system must be                Safe Shutdown Earthquake (SSE). As defined in recom-           taken into account. To ensure that systems whose                Appendix A to 10 CFR Part 100.
of Section II permits increase of tension design limits for the faulted operating condition category by a variable factor which is the smaller value of i.2Sy/Ft or 0.7S 1 ,/Ft. Depending on whether the section considered is a net section at pinholes in eyebars, pin-connected plates, or built-up structural members, F1 may assume the smaller value of 0.45Sy or 0.3 7 5 Su (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 section without pinholes, etc.). Thus greater values of the factor may be obtained for sections at pinholes, which does not account for local stress and is not consistent with NF-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 Rating When load-rating methods are used, Subsection NF and Appendix F of Section Ill do not provide a faulted condition load rating. This guide provides an interim method for the determination of faulted condition load rating.3. Design by Experimental Stress Analysis While the collapse load for the experimental stress analysis method is defined by 11-1430 in Appendix ii of Section II, the design limits for experimental stress analysis for various operating condition categories are not delineated.


This deficiency is remedied by the method described in this guide.4. Large Deformation The design of component supports is an integral part of the design of the system and its components.
les, etc.)          hormal safety-related function occurs during plant con- ditions other than normal or upset (e.g., the function of           Specified Seismic Events. Operating Basis Earth-
: section ECCS during faulted plant conditions) will operate              quake and Safe Shutdown Earthquake.


A complete and consistent design is possible only when system/component/component-support interaction is properly considered.
le factor
:oes not            properly regardless of plant condition, the design limits          System MechanicalLoadings. The static and dynamic nt with            for the design, normal, and upset plant operating                loadings that are developed by the system operating A pro-          condition categories of Subsection NF (which are                parameters, including deadweight, pressure, and other jide.                identical) should be used.                                      non-self-limiting loadings, but excluding effects resulting from constraints of free-end movements and thermal and Since Appendix XVII deriyed all equations from              peak stresses.


When all three are evaluated on an elastic basis, the interaction is usually valid because individual deformations are small. However, if plastic analysis methods are employed in the design process, large deformations that would result in substantially different stress distributions may occur.For the evaluation of the faulted operating condition category, Appendix F of Section IlI permits the use of plastic analysis methods in certain acceptable combina-tions for all three elements.
AISC rules and many AISC.compressior equations have built-in constants based on mechanical properties of                Ultimate Tensile Strength. Material property based
:tion NF
                    steel at room temperature, to use these equations                on engineering stress-strain relationship.


These acceptable combina-tions are selected on the assumption that component supports are more deformation sensitive (i.e., their deformation in general will have a large effect on the Stre Simd but ani met for the avoi S. I Ii natib take norn ditic ECC prop for cond ideni Si AISC built-steel indisc als a matei substc equat mater 6. De Sin load-b Sectio functi Design Onth suppol the str tions i the de-7. Del Des, NF-311 Vessel I Eme tions th Faul associat probabi"" Norn in the c 1.124-2 stress distribution in the system SK Since large deformations always a ononai( ( bution, care should be exercised Lary to ' analysis method is used in the )methodology combination.
a faulted i interim            indiscriminately for all NF and Code Case 1644 materi-               Upset Plant Conditions. Those deviations from the tion load           als at all temperatures would not be prudent. For                normal plant condition that have a high probability of materials other than steel and working temperatures              occurrence.


This is for identifying buckling or instab 0(a) of the change of geometry should be nits for avoid erroneous results, ariable/Ft or 5. Function of Supported System ridered and its components).
substantially different from room temperature, these
ffect the stress ditri-even if tht, plastic Appendix F-approved especially important ility problems where taken into account to'I:n n nected assume.recom-les, etc.): section le factor:oes not nt with A pro-jide.:tion NF a faulted i interim tion load.tal stress idix II of tal stress iodes are by tka (In selecting design limits for different loading combi-.nations, the function of the supported system must be taken into account. To ensure that systems whose hormal safety-related function occurs during plant con-ditions other than normal or upset (e.g., the function of ECCS during faulted plant conditions)
              (      equations should be rederived with the appropriate material propertie
will operate properly regardless of plant condition, the design limits for the design, normal, and upset plant operating condition categories of Subsection NF (which are identical)
should be used.Since Appendix XVII deriyed all equations from AISC rules and many AISC.compressior equations have built-in constants based on mechanical properties of steel at room temperature, to use these equations indiscriminately for all NF and Code Case 1644 materi-als at all temperatures would not be prudent. For materials other than steel and working temperatures substantially different from room temperature, these equations should be rederived with the appropriate material properties.


6. Deformation Limits Since component supports are deformation-sensitive load-bearing elements, satisfying the design limits of Section III will not automatically ensure their proper function.
====s.     ====


Deformation limits, if specified by the Code Design Specification, may be the controlling criterion.
==C. REGULATORY POSITION==
.tal stress                                                                              ASME Codel Class I linear-type component supports idix II of          6. Deformation Limits                                            excluding snubbers, which are not addressed herein, tal stress                                                                            should be constructed to the rules of Subsection NF of iodes are                Since component supports are deformation-sensitive          Section [If as supplemented by the following: 2 by tka          load-bearing elements, satisfying the design limits of Section III will not automatically ensure their proper              1. The classification of component supports should, function. Deformation limits, if specified by the Code           as a minimum, be the same as that of the supported Design Specification, may be the controlling criterion.          components.


On the other hand, if the function of a component support 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 satisfy the design limits for that plant condition.
On the other hand, if the function of a component support is not required for a particular plant condition,           2. Values of Su at a temperature t should be
ýgpal part          the stresses or loads resulting from the loading combina- nents. A                                                                            estimated by either Method I or Method 2 on an interim ly when          tions under that plant condition do not need to satisfy         basis until Section III includes such values.


7. Definitions Design Condition.
action is            the design limits for that plant condition.


The loading condition defined by NF-3112 of Section III of the ASME Boiler and Pressure Vessel Code.Emergency Plant Condition.
ted on an                                                                                  a. Method 1. This method applies to component I because            7. Definitions                                                  support materials whose values of ultimate strength Su if plastic                                                                          at temperature have been tabulated by their manufac- Iprocess,                Design Condition. The loading condition defined by           turers in catalogs or other publications.


Those operating condi-tions that have a low probability of occurrence.
stantially          NF-3112 of Section III of the ASME Boiler and Pressure Vessel Code.


refueling, and shutdown tither than upset, emergency, or faulted plant conditions.
Emergency Plant Condition. Those operating condi- condition            tions that have a low probability of occurrence.                    lAmerican Society of Mechanical Engineers Boiler and the use of                                                                          Pressure Vessel Code, Section Ill. Division 1, 1974 Edition, combina-.              Faulted Plant Condition. Those operating conditions         including the 1974 Winte; Addenda thereto.


Operating Basis Earthquake (OBE). As defined in Appendix A to 10 CFR Part 100.Operating Condition Categories.
combina.         associated with postulated events of extremely low                  21i the function of a component support Is not required urnj~ent            probability.                                                    during a plant condition, the design limits of the support for that S*ie Ier                                                                          plant condition need not be satisfied, provided excessive Normal Plant.condition. Those operating conditions          deflection o: failure of the support will not result in the loss of MLton the                                                                            function of any other safety-related system.


Categories of design limits for component supports as defined by NF-3113 of Section [i1 of the ASME Code.Plant Conditions.
in the course of system startup, operation, hot standby,
                                                                              1.124-3


Operating conditions of the plant categorized as normal, upset, emergency, and faulted plant conditions.
a. The tensile stress limit Ft for a net section as Su  Sur  . but not greater than Sur                    specified in XVII-2211(a) of Section Ill should be the smaller value of 0.6S, or O.5S at temperature. For net sections at pinholes in eye-bars, pin-connected plates, or where                                                                built-up structural members, F, as specified in XVII-
                                                                          2211(b) should be the smaller value of 0.45Sy or Su = ultimate tensile strength at temperature t to be            0.375SU at temperature.


Safe Shutdown Earthquake (SSE). As defined in Appendix A to 10 CFR Part 100.Specified Seismic Events. Operating Basis Earth-quake and Safe Shutdown Earthquake.
used to determine the design limits Sur= ultimate tensile strength at room temperature                        b. The shear stress limit F. for a gross section as specified in XVII.2212 of Section 111 should be the tabulated in Section IN, Appendix i, or Code              smaller value of OASy ir 0.33S, at temperature.


System Mechanical Loadings.
Case 1644-4 Sý =ultimate tensile strength at temperature t tab-                      c. The bearing stress limit F, on the projected area ulated by manufacturers in their catalogs or              of bolts in bearing-type connections as specified in XVf.U-
                other publications                                      2461.2 of Section I1l should be the smaller value of
                                                                          1.35Sy or 0.9Su at temperature, where Sy and S, are


The static and dynamic loadings that are developed by the system operating parameters, including deadweight, pressure, and other non-self-limiting loadings, but excluding effects resulting from constraints of free-end movements and thermal and peak stresses.Ultimate Tensile Strength.
* SLr .ultimate tensile strength at room temperature                material properties of the connected part.


Material property based on engineering stress-strain relationship.
tabulated by manufacturers in the same publi- cations.


Upset Plant Conditions.
Many Lmits and equations for compression strength specified in Sections XVII-2214, X'" 2224, XVII-2225, XVII-2240, and XVII-2260 have bi.-.: -in constants based b. Method 2. This method applies to component                on Young's Modulus of 29,000 Ks: Ftr materials with support materials whose values of ultimate tensile                    Young's Mlodulus at working temperatures substantially strength at temperature have not been tabulated by their              different from 29,000 Ksi, these constants sihould be re- manufacturers in any catalog or publication.                          derived with tie appropriate Young's Modulus unless conservatism .of using these constants as specified can be SU =Sur S                                    demonstrated.


Those deviations from the normal plant condition that have a high probability of occurrence.
Syr where                                                                      4. Component supports designed by linear elastic Su = ultimate tensile strength at temperature t to be analysis may increas, titeir design limits according to the provisions of NF-3231.1(a), XVII-2110(a), and F-1370(a) of Section IlI. The increase of design limits
                                                                                                                                      7)
                used to determine the design limits provided by NF-3231.l(a) is for stress range. The Sur = ultimate tensile strength at room temperature              increase of design limits provided by F-1370(a) for the tabulated in Section 111, Appendix I, or Code              faulted operating condition category should be the Case 1644-4                                                smaller factor of 2 or 1.16 7Su/Sy, if Su > 1.2S., or 1.A
                                                                          if Su < 1.2S y , where Sy and Su are component-support Sy = minimum yield strength at temperature t tab- material properties at temperature.


C. REGULATORY
ulated in Section III, Appendix I, or Code Case
POSITION ASME Codel Class I linear-type component supports excluding snubbers, which are not addressed herein, should be constructed to the rules of Subsection NF of Section [If as supplemented by the following:
                1644-4 However, all increases [i.e., those allowed by Syr    minimum yield strength at room temperature,              NF-3231.1(a), XVII.2110(a), and F-1370(a)] should tabulated in Section III, Appendix 1, or Code            always be limited by XVII-21 10(b) of Section III. The Case 1644-4.                                              critical buckling strengths defined by XVII-21 10(b) of Section III should be calculated using material properties
2 1. The classification of component supports should, as a minimum, be the same as that of the supported components.
        3. The design limits for component supports de-                  at temperature. This increase of design limits does not signed by linear elastic analysis for the design condition            apply to design limits for bolted connections and shear
                                                                  3 and the normal or upset operating condition categories,               stresses. Any increase of design limits for bolted con- when these limits are related to Sy alone, should meet                nections and shear stresses should be justified.


2. Values of Su at a temperature t should be estimated by either Method I or Method 2 on an interim basis until Section III includes such values.a. Method 1. This method applies to component support materials whose values of ultimate strength Su at temperature have been tabulated by their manufac-turers in catalogs or other publications.
the appropriate stress limits of Appendix XVII of Section Ill but should not exceed the limit specified when the value of 5/6 Su is substituted for Sy. Examples                  If the increased design limit for stress range by are shown .below in a and b. The bearing stress limit                NF-3231.1(a) is more than 2 Sy or Su, it should be specified by XVII-2461.2 should be modified by c                      limited to the smaller value of 2Sy or Su unless it can be (below).                                                              justified by a shakedown analysis.


lAmerican Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section Ill. Division 1, 1974 Edition, including the 1974 Winte; Addenda thereto.21i the function of a component support Is not required during a plant condition, the design limits of the support for that plant condition need not be satisfied, provided excessive deflection o: failure of the support will not result in the loss of function of any other safety-related system.&#xfd;gpal part nents. A ly when action is ted on an I because if plastic Iprocess, stantially condition the use of combina-.combina.urnj~ent S*ie Ier MLt on the Faulted Plant Condition.
3 Code operating condition categories only specify design            S. Component supports subjected to the most ad- limits. They are not necessarily related to corresponding plant conditions.                                                          verse combination of the vibratory motion of the OBE          1~~
                                                                    1.124-4
- A


Those operating conditions associated with postulated events of extremely low probability.
and system mechanical loadings 4 associated with either                      b. The emergency condition load rating of the Code design condition or the normal or upset plant                NF-3262.3 of Section [it should not be exceeded for conditions    should be designed within the following                component      supports  designed      by the load-rating limits: 5. 6                                                          method.


Normal Plant .condition.
a. The stress limits of XVII-2000 of Section ifl anf Regulatory Position 3 of this guide should not be                        c. The lower bound collapse load determined by exceeded for component supports designed by. the linear              XVII-4200 adjusted according to the provision of elastic analysis method. These stress limits may be                  XV 1-4110(a) of Section Ill should not be exceeded for increased according to the provisions of NF-323 L.1(a) of            component supports designed by the limit analysis Section I11 and Regulatory Position 4 of this guide when              method.


Those operating conditions in the course of system startup, operation, hot standby, 1.124-3 Su Sur .but not greater than Sur where Su = ultimate tensile strength at temperature t to be used to determine the design limits Sur= ultimate tensile strength at room temperature tabulated in Section IN, Appendix i, or Code Case 1644-4 S&#xfd; =ultimate tensile strength at temperature t tab-ulated by manufacturers in their catalogs or other publications
effects resulting from constraints of free-end mechanical and seismic displacements are added to the loading                            d. The collapse load detcrmined by 11-1400 of combination.                                                          Section III divided by 1.3 should not be exceeded for component supports designed by the experimental stress b. The normal condition load rating or the upset              analysis method.
* SLr .ultimate tensile strength at room temperature tabulated by manufacturers in the same publi-cations.b. Method 2. This method applies to component support materials whose values of ultimate tensile strength at temperature have not been tabulated by their manufacturers in any catalog or publication.


SU =Sur S Syr where Su = ultimate tensile strength at temperature t to be used to determine the design limits Sur = ultimate tensile strength at room temperature tabulated in Section 111, Appendix I, or Code Case 1644-4 Sy = minimum yield strength at temperature t tab-ulated in Section III, Appendix I, or Code Case 1644-4 Syr minimum yield strength at room temperature, tabulated in Section III, Appendix 1, or Code Case 1644-4.3. The design limits for component supports de-signed by linear elastic analysis for the design condition and the normal or upset operating condition categories, 3 when these limits are related to Sy alone, should meet the appropriate stress limits of Appendix XVII of Section Ill but should not exceed the limit specified when the value of 5/6 Su is substituted for Sy. Examples are shown .below in a and b. The bearing stress limit specified by XVII-2461.2 should be modified by c (below).3 Code operating condition categories only specify design limits. They are not necessarily related to corresponding plant conditions.
condition load rating of NF-3262.3 of Section Ill should not be exceeded for component supports designed by the load-rating method.                                                    7. Component supports subjected to the most ad- verse combination of the vibratory motion of &S-Eand c. The lower bound collapse load determined by              system mechanical loadings 4 associated simultaneously XVII-4200 adjusted according to the provision of                      with the faulted plant condition and the normal plant XVII-41 10(a) of Section III should not be exceeded for              condition should be designed within the following design component supports designed by the limit analysis                    limits except when their normal function is required method.                                                                during the faulted plant condition (at which time Regulatory Position g applies): 3 . 5.,6 d. The collapse load determined by 11-1400 of Section III divided by 1.7 should not be exceeded for                        a. The stress limits of XVII-2000of Section III
component supports designed by the experimental stress                and Regulatory Position 3 of this guide, increased analysis method.                                                     according to the provisions of F-1370(a) of Section III
                                                                      and Regulatory Position 4 of this guide, should not be
    6. Component supports subjected to the most ad-                  exceeded for component supports designed by the linear verse combination of system mechanical loadings4 asso-                elastic analysis method.


a. The tensile stress limit Ft for a net section as specified in XVII-2211(a)
ciated with the emergency plant condition should be designed within the following design limits except when                      b. The smaller value of T.L. X 2S/S,            or their normal function is required during the emergency                T.L. X 0.TSu/Su should not be exceeded, where T.L., S,
of Section Ill should be the smaller value of 0.6S, or O.5S at temperature.
plant condition (at which time Regulatory Position 8                  and S, are defined according to NF-3262.1 of Section applies):S. 6                                                          l1l, and Su is the minimum ultimate tensile strength of the material at service temperature for component a. The stress limits of XVII-2000 of Section IlI              supports designed by the load-rating method.


For net sections at pinholes in eye-bars, pin-connected plates, or built-up structural members, F, as specified in XVII-2211(b) should be the smaller value of 0.45Sy or 0.375SU at temperature.
and Regulatory Positions 3 and 4, increased according to the provisions of XVII-2110(a) of Section Ill and                            c. The lower bound collapse load determined by Regulatory Position 4 of this guide, should not be                    XVII-4200 adjusted according to the provision of exceeded for component supports designed by the linear                F-1370(b) of Section III should not be exceeded for elastic analysis method.                                              component supports designed by the limit analysis method.


b. The shear stress limit F. for a gross section as specified in XVII.2212 of Section 111 should be the smaller value of OASy ir 0.33S, at temperature.
*4 System mechanical loadings include all non-self-Limiting                d. The collapse load determined by 11-1400 ad- loadings and do not include loadings resulting from constraints      justed according to the provision of F-1370(b) of of frec-end displacements and thermal or peak stresses.               Section III should not be exceeded for component S$ince component supports are deforma'ion sensitive in the        supports designed by the experimental stress analysis performance of their service requirements, satisfying these criteria does not ensure that their functional requirements will      method.


c. The bearing stress limit F, on the projected area of bolts in bearing-type connections as specified in XVf.U-2461.2 of Section I1l should be the smaller value of 1.35Sy or 0.9Su at temperature, where Sy and S, are material properties of the connected part.Many Lmits and equations for compression strength specified in Sections XVII-2214, X'" 2224, XVII-2225, XVII-2240, and XVII-2260
6e futrlibd. Any deformation limits specified by the design specification may be controlling and should be satisfied.                 8. Component supports whose normal function is
have bi.-.: -in constants based on Young's Modulus of 29,000 Ks: Ftr materials with Young's Mlodulus at working temperatures substantially different from 29,000 Ksi, these constants sihould be re-derived with tie appropriate Young's Modulus unless conservatism .of using these constants as specified can be demonstrated.
    6 Since the design of component supports is an integral part      required during an emergency or faulted plant condition of the design of the system and the design of the component, the      and that are subjected to loading combinations described designer must make sure that methods used for the analysis of the system, component, and component support are compatible          in Regulatory Positions 6 and 7 should be designed (see Table F-1322.2-1 in Appendix F of Section ill). Large            within the design limits described in Regulatory Position deformations in the system or compohnnts should be considered        5 or other justifiable design limits.


4. Component supports designed by linear elastic analysis may increas, titeir design limits according to the provisions of NF-3231.1(a), XVII-2110(a), and F-1370(a)
in the design of component supports.
of Section IlI. The increase of design limits provided by NF-3231.l(a)
is for stress range. The increase of design limits provided by F-1370(a)
for the faulted operating condition category should be the smaller factor of 2 or 1.1 6 7Su/Sy, if Su > 1.2S., or 1.A if Su < 1.2 S y , where Sy and Su are component-support material properties at temperature.


7)However, all increases
1.124-5
[i.e., those allowed by NF-3231.1(a), XVII.2110(a), and F-1370(a)]
should always be limited by XVII-21 10(b) of Section III. The critical buckling strengths defined by XVII-21 10(b) of Section III should be calculated using material properties at temperature.


This increase of design limits does not apply to design limits for bolted connections and shear stresses.
==D. IMPLEMENTATION==
specified porlions of the Commission's regulations, the method described herein will be used in the evaluation        N.


Any increase of design limits for bolted con-nections and shear stresses should be justified.
of submittals for construction permit applications dock- The purpose of this section is t,, provide guidance to applicants and liceiisces regarding tile NRC staff's plans for using this regulatory guide.


If the increased design limit for stress range by NF-3231.1(a)  
eted after JAly 1, 1977. If an applicant wishes to use this regulatory guide in developing submittals for
is more than 2 Sy or Su, it should be limited to the smaller value of 2Sy or Su unless it can be justified by a shakedown analysis.S. Component supports subjected to the most ad-verse combination of the vibratory motion of the OBE 1~~1.124-4-A
                                                                                                                          )
and system mechanical loadings 4 associated with either the Code design condition or the normal or upset plant conditions should be designed within the following limits: 5.6 a. The stress limits of XVII-2000
                                                                construction permit applications docketed on or before Except in those cases in which the applicant proposes        July 1. 1977, the pertinent portions of the application an acceptable alternative method for complying with the         will be evaluated on the basis of this guide.
of Section ifl anf Regulatory Position 3 of this guide should not be exceeded for component supports designed by. the linear elastic analysis method. These stress limits may be increased according to the provisions of NF-323 L.1(a) of Section I11 and Regulatory Position 4 of this guide when effects resulting from constraints of free-end mechanical and seismic displacements are added to the loading combination.


b. The normal condition load rating or the upset condition load rating of NF-3262.3 of Section Ill should not be exceeded for component supports designed by the load-rating method.c. The lower bound collapse load determined by XVII-4200
I ~
adjusted according to the provision of XVII-41 10(a) of Section III should not be exceeded for component supports designed by the limit analysis method.d. The collapse load determined by 11-1400 of Section III divided by 1.7 should not be exceeded for component supports designed by the experimental stress analysis method.6. Component supports subjected to the most ad-verse combination of system mechanical loadings 4 asso-ciated with the emergency plant condition should be designed within the following design limits except when their normal function is required during the emergency plant condition (at which time Regulatory Position 8 applies):S.
                                                          1.124-6}}
 
6 a. The stress limits of XVII-2000
of Section IlI and Regulatory Positions
3 and 4, increased according to the provisions of XVII-2110(a)
of Section Ill and Regulatory Position 4 of this guide, should not be exceeded for component supports designed by the linear elastic analysis method.* 4 System mechanical loadings include all non-self-Limiting loadings and do not include loadings resulting from constraints of frec-end displacements and thermal or peak stresses.S$ince component supports are deforma'ion sensitive in the performance of their service requirements, satisfying these criteria does not ensure that their functional requirements will 6e futrlibd.
 
Any deformation limits specified by the design specification may be controlling and should be satisfied.
 
6 Since the design of component supports is an integral part of the design of the system and the design of the component, the designer must make sure that methods used for the analysis of the system, component, and component support are compatible (see Table F-1322.2-1 in Appendix F of Section ill). Large deformations in the system or compohnnts should be considered in the design of component supports.b. The emergency condition load rating of NF-3262.3 of Section [it should not be exceeded for component supports designed by the load-rating method.c. The lower bound collapse load determined by XVII-4200
adjusted according to the provision of XV 1-4110(a)
of Section Ill should not be exceeded for component supports designed by the limit analysis method.d. The collapse load detcrmined by 11-1400 of Section III divided by 1.3 should not be exceeded for component supports designed by the experimental stress analysis method.7. Component supports subjected to the most ad-verse combination of the vibratory motion of &S-E and system mechanical loadings 4 associated simultaneously with the faulted plant condition and the normal plant condition should be designed within the following design limits except when their normal function is required during the faulted plant condition (at which time Regulatory Position g applies): 3.5., 6 a. The stress limits of XVII-2000of Section III and Regulatory Position 3 of this guide, increased according to the provisions of F-1370(a)
of Section III and Regulatory Position 4 of this guide, should not be exceeded for component supports designed by the linear elastic analysis method.b. The smaller value of T.L. X 2S/S, or T.L. X 0.TSu/Su should not be exceeded, where T.L., S, and S, are defined according to NF-3262.1 of Section l1l, and Su is the minimum ultimate tensile strength of the material at service temperature for component supports designed by the load-rating method.c. The lower bound collapse load determined by XVII-4200
adjusted according to the provision of F-1370(b)
of Section III should not be exceeded for component supports designed by the limit analysis method.d. The collapse load determined by 11-1400 ad-justed according to the provision of F-1370(b)
of Section III should not be exceeded for component supports designed by the experimental stress analysis method.8. Component supports whose normal function is required during an emergency or faulted plant condition and that are subjected to loading combinations described in Regulatory Positions
6 and 7 should be designed within the design limits described in Regulatory Position 5 or other justifiable design limits.1.124-5
 
==D. IMPLEMENTATION==
The purpose of this section is t,, provide guidance to applicants and liceiisces regarding tile NRC staff's plans for using this regulatory guide.Except in those cases in which the applicant proposes an acceptable alternative method for complying with the specified porlions of the Commission's regulations, the method described herein will be used in the evaluation of submittals for construction permit applications dock-eted after JAly 1, 1977. If an applicant wishes to use this regulatory guide in developing submittals for construction permit applications docketed on or before July 1. 1977, the pertinent portions of the application will be evaluated on the basis of this guide.N.)I~1.124-6}}


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Revision as of 11:16, 4 November 2019

Design Limits and Loading Combinations for Class 1 Linear-Type Component Supports
ML13350A273
Person / Time
Issue date: 11/30/1976
From:
NRC/OSD
To:
References
RG-1.124
Download: ML13350A273 (6)


. : ..... . -,- .... * .,. :..-.*.- .:,

.a.

U.S. NUCLEAR REGULATORY COMMISSION November 1976 REGULATORY GU`DE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 1.124 DESIGN LIMITS AND LOADING COMBINATIONS

FOR CLASS 1 LINEAR-TYPE COMPONENT SUPPORTS

A. INTRODUCTION

General Design Criterion 2, "Design Bases for Protec- NF-1122 and NA-2134 of Section Ill of the ASME

ion 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, be

0 CFR Part 50, "Licensing of Production and Utiliza- the same as that of the supported componets. This ion Facilities," requires, in part, that the design bases

[ should be considered as a requirement. This guide or structures, systems, and components important to delineates design limits and loading combinations, in afety reflect appropriate combinations of the effects of addition to supplerientary criteria, for ASME Class I

ormal and accident conditions with the effects of linear-type componmi.t supports as defined by NF.1213 atural phenomena such as earthquakes. The failure of of Section Ill. Snubbers uistalled for protection against aembers designed to support safety-related components seismic or dynamic loadings of other origins are not ould jeopardize the ability of the supported component addressed in this guide.

o perform its safety function.

  • Pu ,..-

sit on.. NF ad Ap e dx.V*ofS cioI

This guide delineates acceptable design limits and Subsction NF and Appendix XVII of Section III

ppropriate combinations of loadings associated waith ..-' mpernitthe use of four methods for the design of Class I

ormal operation, postulated accidents, and specified liniear-type component supports: linear elastic analysis.

.0 pismic

  • omponn events anentsupportas for supportss defined in'

,ction IlI of the American Society of M.echanic.,

the design of Class

..

SOlno n;ubsection cio N-pe NFP of load rating, experimental stress analysis, and limit

"-..-analysis. For each method, , . the,.. ASME Code delineates allowable stress or loading limits for various Code

.

ngincers (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 from the appropriate plant conditions. However, the Codc's

B. DISCUSSION

..`. operating condition categories are simply component Load-be Loa-baring members em rsclasslif. 'd ;as "component sup-. support df design limits; they are not necessarily related to

! orts are essential to th safety of nuclear power ants sine theysrentain como nents"i paceaurig ther ants since they retain companents In place during the

)adings associated with normal, upset, and emergency ant counuiions unuer. me suess of specifieu seismic ents, thereby permitting system components to func- n properly. They also prevent excessive component ovement during combined the loadings associated with a seismic faulted fined plant conditions. Since the Code does not specify loading combinations, guidance is required to provide a consistent basis for the design of compoitent supports.

The component supports considered in this guide are located within containment and are therefore assumed pnt condition with the specified to be protected against loadings froin natural phenoin- ent, thus helping to mitigate the consequences of ena or man-made hazards other than the specified stem damage. Component supports are deformation seismic events. Thus only the specified seismic events nsitivc because large deformations in thenm may signifi- need to be considered in combination with the loadings atly change the stress distribution in the support associated with plant conditions to develop appropriate fstem and its supported components. loading combinations.

USNRC REGULATORY GUIDES Comments sho-id be sent to the Secretary of the Commlssion. U.S. Nuclear Regulatory Commission, Washington, D.C. 20566. Attention: Docketing and Pguleory Guide* are Issued to describe and make oawilahl to the public Servi.e Soction.

a rthod acceptaeble ta the NRC stall of Iemplamsnting traincc pPAs of the tlmmslaion'i requlmitlons. to delneate tachpiques used by the stilt in vlmu.

The guides ere Issued In the following ten braid disialone:

n9 Sptecific probiem's a' co-'atuted accidents, ot to provide quldanel to eppli- Ito. iegutetor Guids are not substitutes tor reguletions. and con-,liance h then I ncot required, Methods and ssitmtas difsroot tnom triosi %trcut In 1. Power Reactors S. Products

2. Rauaatch and Teot Reectot,

7. Tianipottiion

  • 0

guides will be ccuptaible it they provide a beasi Io, the lCndhg ruuUiaite tO

isuafnceilOof inIotuence of a orl liercense theth aomn*,ssin.,.

3. Fuels and 6.1stetoe Factiltjia

1. Occupational Health

4. Environmental and S;tlni

9. Antitrust Review

1",ent2 and suggestions fur improwqnients In theseu fl-de, are incouraoed 5. MuArletIl end Plant Proltctiun to. en.eral

',-s 5 0,4 guides will be ivied.,

efl s pr*pproittri. to *ccuotnnousat coat.

  • 'tnd it %tflct new information or eApartence. H'eot, or comrmtent on Coroleaof pubilihed gvilet mme be obtained by written request irdlcatitg l1.4

"' -i-d within ebout two ninnih$s After its isoasnee. will Dc par.

a eValtuating the naed tot an aur;Vrov.vion. divisiort deuied to -no U S. Nuclear Reguiatosry Commistlon. Washington. D.C.

ME&. Attention; D;rector. Office of Standards Develorment.

-- 7rerý__r, 7.1 !7ý-ý.

77 7.-".74.

i. ., :. ..

1. Design by Linear Elastic Analysis shakedown. For many allowable stresses above the value Stre of 0.6S%.. the increase permitted by NF-323 1.1 (a) will be Simd a. S, at Temperature. When the linear elastic anal- above t'he value of 2Sx and will thus violate the normal but ysis method is used to design Class I linear-type shakedown range. A shakedown analysis is necessary to ani component supports, material properties are given by justify the increase of stress above 2Sy or SU . met Tables 1-13.1 and 1-13.3 in Appendix I of Section III and for Tables 3 and 4 in Code Case 1644-4. These tables list For the linear elastic analysis method, F-1370(a) of the values for the minimum yield strength Sy at various Section II permits increase of tension design limits for avoi temperatures but only room temperature values for the the faulted operating condition category by a variable ultimate tensile strength Su. At room temperature, Sy factor which is the smaller value of i.2Sy/Ft or S. I

varies from 50% to 87% of Su for component su-port 0.7S1,/Ft. Depending on whether the section considered materials. is a net section at pinholes in eyebars, pin-connected Ii plates, or built-up structural members, F1 may assume natib Design limits derived from either material property the smaller value of 0.45Sy or 0 .3 7 5 Su (as recom- take alone may not be sufficient to provide a consistent mended by this guide for a net section at pinholes, etc.) norn design margin. This is recognized by Section HI, since or the smaller value of 0.6Sy or O.5Su (for a net section ditic XVU-221 l(a) of Section I1l defines the allowable stress without pinholes, etc.). Thus greater values of the factor ECC

in tension on a net section as the smaller value of 0.6Sy may be obtained for sections at pinholes, which does not prop and O.5Su. To alleviate the lack of defined values of S, account for local stress and is not consistent with for at temperatures above room temperature and to provide NF-3231.1 and XVII-2110(a) 6f Section I11. A pro- cond a safe design margin, an interim method is given in this cedure to correct this factor is provided in this guide. ideni guide to obtain values of Su at temperature.

2. Design by Load Rating Si While XVII-221 1(a) specifies allowable tensile stress AISC

in terms of both Sy and Su, the rest of XVII-2000 When load-rating methods are used, Subsection NF built- specifies other allowable design limits in terms of Sy and Appendix F of Section Ill do not provide a faulted steel only. This does not maintain a consistent design margin condition load rating. This guide provides an interim indisc for those design limits related only to material proper- method for the determination of faulted condition load als a ties. Modifications similar to XVII-2211(a) should be rating. matei employed for all those design limit

s. substc

3. Design by Experimental Stress Analysis equat b. Increase of Design Limits. While NF-3231.1(a), mater XVII-21 10(a), and F-1370(a) of Section III all permit While the collapse load for the experimental stress the increase of allowable stresses under various loading analysis method is defined by 11-1430 in Appendix ii of 6. De conditions, XVII-21 10(b) limits the increase so that Section II, the design limits for experimental stress two-thirds of the critical buckling stress for compression analysis for various operating condition categories are Sin and compression flange members is not excee:. d, and not delineated. This deficiency is remedied by the load-b the increase allowed by NF-3231.1(a) is for stres- range. method described in this guide. Sectio Critical buckling stresses with normal design margins are functi derived in XVII-2200 of Section Ill. Since buckling 4. Large Deformation Design prevents "shakedown" in a load-bearing member, XVII- Onth

2110(b) must be regarded as controlling. Also, buckling The design of component supports is an integral part suppol is the result of the interaction of the configuration of of the design of the system and its components. A the str the load-bearing member and its material properties (i.e., complete and consistent design is possible only when tions i elastic modulus E and minimum yield strength Sy). system/component/component-support interaction is the de- Because both of these material properties change with properly considered. When all three are evaluated on an temperature, the critical buckling stresses should be elastic basis, the interaction is usually valid because 7. Del calculated with the values of E and Sy of the component individual deformations are small. However, if plastic support material at temperature. Allowable design limits analysis methods are employed in the design process, Des, for bolted connections are derived from tensile and shear large deformations that would result in substantially NF-311 stress limits and their nonlinear interaction; they also different stress distributions may occu

r. Vessel I

change with the size of the bolt. For this reason, the increases permitted by NF-3231.1, XVII-2110(a), and For the evaluation of the faulted operating condition Eme F-1370(a) of Section Ill are not directly applicable to tions th category, Appendix F of Section IlI permits the use of allowable shear stresses and allowable stresses for bolts plastic analysis methods in certain acceptable combina- Faul and bolted connections. tions for all three elements. These acceptable combina- associat tions are selected on the assumption that component probabi The range of primary plus secondary stresses should supports are more deformation sensitive (i.e., their be limited to 2Sy but not more than Su to ensure deformation in general will have a large effect on the "" Norn in the c

1.124-2

stress distribution in the system and its components). refueling, and shutdown tither than upset, emergency, or SK Since large deformations always affect the stress ditri- faulted plant conditions.

ononai( ( bution, care should be exercised even if tht, plastic Lary to ' analysis method is used in the )Appendix F-approved Operating Appendix A toBasis

10 CFR Part 100. (OBE). As defined in Earthquake methodology combination. This is especially important for identifying buckling or instab ility problems where Operating Condition Categorie

s. Categories of design

'I0(a) of the change of geometry should be taken into account to limits for component supports as defined by NF-3113 of nits for avoid erroneous results, Section [i1 of the ASME Code.

n ariable

5. Function of Supported System Plant Conditions. Operating conditions of the plant

/Ft or categorized as normal, upset, emergency, and faulted ridered In selecting design limits for different loading combi- plant conditions.

nnected assume. .nations, the function of the supported system must be Safe Shutdown Earthquake (SSE). As defined in recom- taken into account. To ensure that systems whose Appendix A to 10 CFR Part 100.

les, etc.) hormal safety-related function occurs during plant con- ditions other than normal or upset (e.g., the function of Specified Seismic Events. Operating Basis Earth-

section ECCS during faulted plant conditions) will operate quake and Safe Shutdown Earthquake.

le factor

oes not properly regardless of plant condition, the design limits System MechanicalLoadings. The static and dynamic nt with for the design, normal, and upset plant operating loadings that are developed by the system operating A pro- condition categories of Subsection NF (which are parameters, including deadweight, pressure, and other jide. identical) should be used. non-self-limiting loadings, but excluding effects resulting from constraints of free-end movements and thermal and Since Appendix XVII deriyed all equations from peak stresses.

AISC rules and many AISC.compressior equations have built-in constants based on mechanical properties of Ultimate Tensile Strength. Material property based

tion NF

steel at room temperature, to use these equations on engineering stress-strain relationship.

a faulted i interim indiscriminately for all NF and Code Case 1644 materi- Upset Plant Conditions. Those deviations from the tion load als at all temperatures would not be prudent. For normal plant condition that have a high probability of materials other than steel and working temperatures occurrence.

substantially different from room temperature, these

( equations should be rederived with the appropriate material propertie

s.

C. REGULATORY POSITION

.tal stress ASME Codel Class I linear-type component supports idix II of 6. Deformation Limits excluding snubbers, which are not addressed herein, tal stress should be constructed to the rules of Subsection NF of iodes are Since component supports are deformation-sensitive Section [If as supplemented by the following: 2 by tka load-bearing elements, satisfying the design limits of Section III will not automatically ensure their proper 1. The classification of component supports should, function. Deformation limits, if specified by the Code as a minimum, be the same as that of the supported Design Specification, may be the controlling criterion. components.

On the other hand, if the function of a component support is not required for a particular plant condition, 2. Values of Su at a temperature t should be

ýgpal part the stresses or loads resulting from the loading combina- nents. A estimated by either Method I or Method 2 on an interim ly when tions under that plant condition do not need to satisfy basis until Section III includes such values.

action is the design limits for that plant condition.

ted on an a. Method 1. This method applies to component I because 7. Definitions support materials whose values of ultimate strength Su if plastic at temperature have been tabulated by their manufac- Iprocess, Design Condition. The loading condition defined by turers in catalogs or other publications.

stantially NF-3112 of Section III of the ASME Boiler and Pressure Vessel Code.

Emergency Plant Condition. Those operating condi- condition tions that have a low probability of occurrence. lAmerican Society of Mechanical Engineers Boiler and the use of Pressure Vessel Code, Section Ill. Division 1, 1974 Edition, combina-. Faulted Plant Condition. Those operating conditions including the 1974 Winte; Addenda thereto.

combina. associated with postulated events of extremely low 21i the function of a component support Is not required urnj~ent probability. during a plant condition, the design limits of the support for that S*ie Ier plant condition need not be satisfied, provided excessive Normal Plant.condition. Those operating conditions deflection o: failure of the support will not result in the loss of MLton the function of any other safety-related system.

in the course of system startup, operation, hot standby,

1.124-3

a. The tensile stress limit Ft for a net section as Su Sur . but not greater than Sur specified in XVII-2211(a) of Section Ill should be the smaller value of 0.6S, or O.5S at temperature. For net sections at pinholes in eye-bars, pin-connected plates, or where built-up structural members, F, as specified in XVII-

2211(b) should be the smaller value of 0.45Sy or Su = ultimate tensile strength at temperature t to be 0.375SU at temperature.

used to determine the design limits Sur= ultimate tensile strength at room temperature b. The shear stress limit F. for a gross section as specified in XVII.2212 of Section 111 should be the tabulated in Section IN, Appendix i, or Code smaller value of OASy ir 0.33S, at temperature.

Case 1644-4 Sý =ultimate tensile strength at temperature t tab- c. The bearing stress limit F, on the projected area ulated by manufacturers in their catalogs or of bolts in bearing-type connections as specified in XVf.U-

other publications 2461.2 of Section I1l should be the smaller value of

1.35Sy or 0.9Su at temperature, where Sy and S, are

  • SLr .ultimate tensile strength at room temperature material properties of the connected part.

tabulated by manufacturers in the same publi- cations.

Many Lmits and equations for compression strength specified in Sections XVII-2214, X'" 2224, XVII-2225, XVII-2240, and XVII-2260 have bi.-.: -in constants based b. Method 2. This method applies to component on Young's Modulus of 29,000 Ks: Ftr materials with support materials whose values of ultimate tensile Young's Mlodulus at working temperatures substantially strength at temperature have not been tabulated by their different from 29,000 Ksi, these constants sihould be re- manufacturers in any catalog or publication. derived with tie appropriate Young's Modulus unless conservatism .of using these constants as specified can be SU =Sur S demonstrated.

Syr where 4. Component supports designed by linear elastic Su = ultimate tensile strength at temperature t to be analysis may increas, titeir design limits according to the provisions of NF-3231.1(a), XVII-2110(a), and F-1370(a) of Section IlI. The increase of design limits

7)

used to determine the design limits provided by NF-3231.l(a) is for stress range. The Sur = ultimate tensile strength at room temperature increase of design limits provided by F-1370(a) for the tabulated in Section 111, Appendix I, or Code faulted operating condition category should be the Case 1644-4 smaller factor of 2 or 1.16 7Su/Sy, if Su > 1.2S., or 1.A

if Su < 1.2S y , where Sy and Su are component-support Sy = minimum yield strength at temperature t tab- material properties at temperature.

ulated in Section III, Appendix I, or Code Case

1644-4 However, all increases [i.e., those allowed by Syr minimum yield strength at room temperature, NF-3231.1(a), XVII.2110(a), and F-1370(a)] should tabulated in Section III, Appendix 1, or Code always be limited by XVII-21 10(b) of Section III. The Case 1644-4. critical buckling strengths defined by XVII-21 10(b) of Section III should be calculated using material properties

3. The design limits for component supports de- at temperature. This increase of design limits does not signed by linear elastic analysis for the design condition apply to design limits for bolted connections and shear

3 and the normal or upset operating condition categories, stresses. Any increase of design limits for bolted con- when these limits are related to Sy alone, should meet nections and shear stresses should be justified.

the appropriate stress limits of Appendix XVII of Section Ill but should not exceed the limit specified when the value of 5/6 Su is substituted for Sy. Examples If the increased design limit for stress range by are shown .below in a and b. The bearing stress limit NF-3231.1(a) is more than 2 Sy or Su, it should be specified by XVII-2461.2 should be modified by c limited to the smaller value of 2Sy or Su unless it can be (below). justified by a shakedown analysis.

3 Code operating condition categories only specify design S. Component supports subjected to the most ad- limits. They are not necessarily related to corresponding plant conditions. verse combination of the vibratory motion of the OBE 1~~

1.124-4

- A

and system mechanical loadings 4 associated with either b. The emergency condition load rating of the Code design condition or the normal or upset plant NF-3262.3 of Section [it should not be exceeded for conditions should be designed within the following component supports designed by the load-rating limits: 5. 6 method.

a. The stress limits of XVII-2000 of Section ifl anf Regulatory Position 3 of this guide should not be c. The lower bound collapse load determined by exceeded for component supports designed by. the linear XVII-4200 adjusted according to the provision of elastic analysis method. These stress limits may be XV 1-4110(a) of Section Ill should not be exceeded for increased according to the provisions of NF-323 L.1(a) of component supports designed by the limit analysis Section I11 and Regulatory Position 4 of this guide when method.

effects resulting from constraints of free-end mechanical and seismic displacements are added to the loading d. The collapse load detcrmined by 11-1400 of combination. Section III divided by 1.3 should not be exceeded for component supports designed by the experimental stress b. The normal condition load rating or the upset analysis method.

condition load rating of NF-3262.3 of Section Ill should not be exceeded for component supports designed by the load-rating method. 7. Component supports subjected to the most ad- verse combination of the vibratory motion of &S-Eand c. The lower bound collapse load determined by system mechanical loadings 4 associated simultaneously XVII-4200 adjusted according to the provision of with the faulted plant condition and the normal plant XVII-41 10(a) of Section III should not be exceeded for condition should be designed within the following design component supports designed by the limit analysis limits except when their normal function is required method. during the faulted plant condition (at which time Regulatory Position g applies): 3 . 5.,6 d. The collapse load determined by 11-1400 of Section III divided by 1.7 should not be exceeded for a. The stress limits of XVII-2000of Section III

component supports designed by the experimental stress and Regulatory Position 3 of this guide, increased analysis method. according to the provisions of F-1370(a) of Section III

and Regulatory Position 4 of this guide, should not be

6. Component supports subjected to the most ad- exceeded for component supports designed by the linear verse combination of system mechanical loadings4 asso- elastic analysis method.

ciated with the emergency plant condition should be designed within the following design limits except when b. The smaller value of T.L. X 2S/S, or their normal function is required during the emergency T.L. X 0.TSu/Su should not be exceeded, where T.L., S,

plant condition (at which time Regulatory Position 8 and S, are defined according to NF-3262.1 of Section applies):S. 6 l1l, and Su is the minimum ultimate tensile strength of the material at service temperature for component a. The stress limits of XVII-2000 of Section IlI supports designed by the load-rating method.

and Regulatory Positions 3 and 4, increased according to the provisions of XVII-2110(a) of Section Ill and c. The lower bound collapse load determined by Regulatory Position 4 of this guide, should not be XVII-4200 adjusted according to the provision of exceeded for component supports designed by the linear F-1370(b) of Section III should not be exceeded for elastic analysis method. component supports designed by the limit analysis method.

  • 4 System mechanical loadings include all non-self-Limiting d. The collapse load determined by 11-1400 ad- loadings and do not include loadings resulting from constraints justed according to the provision of F-1370(b) of of frec-end displacements and thermal or peak stresses. Section III should not be exceeded for component S$ince component supports are deforma'ion sensitive in the supports designed by the experimental stress analysis performance of their service requirements, satisfying these criteria does not ensure that their functional requirements will method.

6e futrlibd. Any deformation limits specified by the design specification may be controlling and should be satisfied. 8. Component supports whose normal function is

6 Since the design of component supports is an integral part required during an emergency or faulted plant condition of the design of the system and the design of the component, the and that are subjected to loading combinations described designer must make sure that methods used for the analysis of the system, component, and component support are compatible in Regulatory Positions 6 and 7 should be designed (see Table F-1322.2-1 in Appendix F of Section ill). Large within the design limits described in Regulatory Position deformations in the system or compohnnts should be considered 5 or other justifiable design limits.

in the design of component supports.

1.124-5

D. IMPLEMENTATION

specified porlions of the Commission's regulations, the method described herein will be used in the evaluation N.

of submittals for construction permit applications dock- The purpose of this section is t,, provide guidance to applicants and liceiisces regarding tile NRC staff's plans for using this regulatory guide.

eted after JAly 1, 1977. If an applicant wishes to use this regulatory guide in developing submittals for

)

construction permit applications docketed on or before Except in those cases in which the applicant proposes July 1. 1977, the pertinent portions of the application an acceptable alternative method for complying with the will be evaluated on the basis of this guide.

I ~

1.124-6