Regulatory Guide 1.48

Design Limits and Loading Combinations for Seismic Category I Fluid Systems Components

ML12298A124
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Issue date:	05/31/1973
From:	Office of Nuclear Regulatory Research
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RG-01.048
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May 1973U.S. ATOMIC ENERGY COMMISSIONR~ GULATO GiEDIRECTORATE OF REGULATORY STANDARDS,REGULATORY GUIDE 1.48DESIGN LIMITS AND LOADING COMBINATIONSFOR SEISMIC CATEGORY I FLUID SYSTEM COMPONENTSA. INTRODUCTIONGeneral Design Criterion 2, "Design Bases forProtection Against Natural Phenomena," of Appendix Ato 10 CFR Part 50, "General Design Criteria for NuclearPower Plants," requires, in part, that the design bases forstructures, systems, and components important to safetyreflect appropriate combinations of the effects ofnormal and accident conditions with the effects ofnatural phenomena such as earthquakes. This guidedelineates acceptable design limits and appropriatecombinations of loadings associated with normaloperation, postulated accidents, and specified seismicevents for the design of Seismic Category I fluid systemcomponents (i.e., water- and steam-containingcomponents). This guide applies to light-water-cooledreactors. The Advisory Committee on ReactorSafeguards has been consulted concerning this guide andhas concurred in the regulatory position.B. DISCUSSION'The design conditions and functional requirementsof fluid system components important to safety innuclear power, plants should be reflected in theapplication of appropriate design limits (e.g., stress orstrain limits) for the most adverse combination ofloadings to which these components may be subjected inservice.For components that are constructed in accordancewith Section III of the American Society of MechanicalEngineers (ASME) Boiler and Pressure Vessel Code,provision of a design specification which stipulates thedesign requirements for the component: (i.e., themechanical and 'operational loadings) and the Codeclassification of the component (e.g., Code Class 1, 2, or3) is required. However, neither Section III nor anyother published national code or standard providesadequate guidance for selecting code classifications andloading combinations for design or for identifyingSeismic Category I fluid system components. The lack ofadequate guidance: for selecting loading combinations isapparent from. a review of recent construction permitapplications which :reflect design requirements, ascontained in the code design specifications. Fore~sentially identical components designed for the sameplant conditions (i.e., operating conditions of the plantcategorized as normal, upset, emergency, and faultedplant conditions) and specified seismic events (i.e.,one-half the Safe Shutdown Earthquake (SSE) and theSSE) the. loading combinations and asso'ciated designlimits, vary considerably : among applications forconstruction permits. Regulatory Guides 1.26 and 1.29(Safety Guide 26 and 29) entitled "Quality GroupClassifications and Standards" and "Seismic DesignClassification," respectively, provide acceptable bases forclassifying fluid system components in relation toapplicable national codes (e.g.,Section III of the ASMECode) and for-identifying th6se striuctures, systems andcomponents that: should be designed to remainfunctional under the effects Of the SSE (i.e., SeismicCategory I structures, systems, and components).To further provide a consistent basis for design offluid system comipoiient's important to safety, this guidedelineates acceptable design limits and appropriatecombinations' of, loadings associated with applicableplant conditions arid specified seismic events. Theapproach set' forth in this guide is directly related toSection III of the ASME Code. Design limits as specifiedin Section III are extensively utilized to provideassurance of ýthie pressure-retaining integrity of vessels,piping, non:active pumps, and non-active valves of eachCode class; however',: for the particular case of activepumnIps and valves (i.e.,`pumps and valves that mustperforms a mechanical motion during' the course ofaccomplishing a 'syst'eni safety function), special designlimits and supplemental requirements are specified toprovide assurance of operability. These special designUSAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the divisionsdesired to the US. Atomic Energy Commission, Washington, D.C. 20545,Regulatory Guides are issued to describe and make available to the public Attention: Director of Regulatory Standards. Comments and suggestions formethods acceptable to the AEC Regulatory staff of implementing specific5parts of improvements in these guides are encouraged and should be sent to the Secretarythe Commission's regulations, to delineate techniques used by the staff in of the Commission, US-: Atomic Energy Commission, Washington, D.C. 20545,evaluating specific problems or postulated accidents, or to provide guidance to Attention: Chief, Public Proceedings Staff.applicants. Regulatory Guides are not' substitutes for regulations and compliance -"with them is not required. Methods and solutions different from those set out in The guides are issued in the following ten broad divisions:the guides will be acceptable if they provide a basis for the findings requisite tothe issuance or continuance of a permit or license by the Commission. 1. Power Reactors 6. Products2. Research and Test Reactors 7. Transportation-3. Fuels and Materials Facilities a. Occupational HealthPublished guides will be revised periodically, as appropriate, to accommodate 4. Environmental and Siting 9. Antitrust Reviewcomments and to reflect new information or experience. 5. Materials and Plant Protection 10. General limits and supplemental requirements are provided foractive pumps and valves because the rules forconstructi6n of Section II1 apply to the assurance ofpressure-retaining integrity but do not assure that pumpsand valves designated to perform a system safetyfunction will operate when required. This conclusion issupported by B-1223.4(b) of Appendix B to Section III,"Owner's Design Specification;' which states, "AlthoughCode requirements for the acceptability of a componentare not intended to assure the functional adequacy ofthe component, the higher stress limits permitted forEmergency and Faulted Condition evaluation may resultin deformations which preclude operability during orafter the event. The. Owner may wish to provide morerestrictive limits for components which require closedimensional control and which must operate during andafter the event. Such requirements are beyond the scopeof this Section (i.e., Section I11)." Footnote 1 toNB-35 10 of Section III also expresses this limitation bystating that, "These requirements for the acceptabilityof a valve design are not intended to assure thefunctional adequacy of the valve."In addition, design limits augmenting Section III ofthe ASME Code are selected for Code Class 2 and 3components and certain Code Class 1 components in theabsence of design limits for other than the normal plantcondition (e.g., the emergency and faulted plantconditions). It is emphasized that the design limitsdelineated in this guide are intended to apply to all fluidsystem components (vessels, piping, pumps, and valves)that are relied upon to cope with the effects of specifiedplant conditions.Loading combinations are defined as those loadingsor combinations thereof-that are associated with eachplant condition or specified seismic event. Theseloadings result from'the various transients or events thatare included within each plant condition and themagnitude of the specified seismic events associated withthe nuclear power plant site. Identification of theparticular transients or events to be evaluated for eachplant condition will be addressed in a future guide;however, only the most adversejloadings resulting fromthose transients or events associated with each plantcondition and specified seismic event as combined hereinshould be considered for design (e.g., thosecombinations of loadings that result in the limiting orcontrolling design condition). The combinations ofloadings are based upon information contained in recentapplications for construction permits, the anticipatedsequence of' occurrences which produ'ce loadings, andthe most limiting combination of low-probabilitypostulated accidents or events (i.e., the concurrentloadings associated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition).Although the loadings associated with each plantcondition and specified seismic event delineated in thisguide are combined in the same maniner for all classes ofcomponents, the design limits 'and specific loadingsassociated with each plant condition-are not the samefor all classes of components (e.g., the dynamic loadingsassociated with the faulted plant condition may not bepresent for all Code Class 2 and 3 components becausepiping ruptures may be postulated to occur only- forcertain Code Class 2 and 3 piping). However, a failure inany system or component should be evaluated for its.effects on all other systems and components.ASME Code Class 1 ComponentsCode Class I components, except for pumps andvalves, benefit from the most complete design coveragethat Section III of the ASME Code provides. Designrules and design limits are available for other than thenormal plant condition (e.g., for the severe loadingsassociated with the emergency and faulted plantconditions and specified seismic events). These severeloadings are accomodated by application of the designlimits for the emergency and faulted operating conditioncategories (as defined in NB-3113 of Section 111) whichpermit design limits in excess of those allowed for thenormal operating condition category. Loadingsassociated with the normal plant condition and loadingsassociated with the upset plant condition (i.e.,anticipated operational occurrences as defined inAppendix A to 10 CFR Part 50) are sustained byapplication of the design limits specified for the normaloperating condition category and the upset operatingcondition category of Section III, respectively.ASME Code Class 1 Vessels and PipingTo provide assurance of pressure-retaining integrity,the upset, emergency, and faulted operating conditioncategory design limits given in NB-3200, "Design byAnalysis," and NB-3600, "Piping Design," of Section IIIof the ASME Code should be applied to design vesselsand piping for the combination of loadings delineated inregulatory positions l.a., 1.b., and l.c., respectively.Non-Active ASME Code Class 1 Pumps and Valves(Designed by Analysis)As permitted by Section III of the ASME Codewithin the limitations of NB-3400 and NB-32 11, CodeClass I pumps may be designed by analysis (i.e., thedesign procedures specified in NB-3200 of Section III).Case 1552 (Interpretations of ASME Boiler and PressureVessel Code) allows design by analysis of Code Class Ivalves if additional requirements are met. Non-activepumps and valves are those pumps and valves thatare,pot required to perform a mechanical motion during the-course of accomplishing a system safety function. Since-non-active pumps and valves need only be assured ofpressure-retaining integrity, the upset, emergency, andfaulted operating condition category design limits ofNB-3200 should be designated for the combination ofloadings delineated in regulatory positions 2.a., 2.b., and2.c., respectively.Non-Active ASME Code Class 1 Valves (Designed byStandard or Alternative Design Rules).01.48-2 Standard or alternative design rules for Code Class 1valves are specified by, NB-3512 and NB-3513 of SectionIII of the ASME Code. These design rules encompass theuse of pressure-temperature ratings of valves. The designlimits specified in, this guide are in terms of Pr whichdiffers from the definition given by Section III in that Pris related to maximum transient temperature in lieu ofthe design temperature.. Pr is defined in this guide. as theprimary-pressure rating corresponding to the maximumtransient temperature for each plant condition asspecified in Tables NB-3531-1 to NB-3531-7 of Section.III..Therefore, the maximum transient temperature foreach plant condition should be determined before thepressure rating of, the valve is. selected (e.g., Class 600,900, or 1500). In order to provide assurance ofpressure-retaining integrity, Pr should not be exceeded,by more than 10, 20, and 50 percent when the valve issubjected. to the combination of loadings delineated inregulatory positions 3.a., 3.b., and 3.c., respectively. Onehundred ten percent and 120 percent ,of Pr, respectively,are analogous to the upset and emergency operatingcondition category limits of NB-3200 of Section III. Onehundred fifty percent of Pr is analogous to thehydrostatic test pressure specified for Code Class 1valves in Section III.Active ASME Code Class 1 Pumps and Valves (Designedby Analysis)The normal operating condition category designlimits given by NB-3222 of Section III should be appliedto design active pumps and valves for the combination ofloadings delineated in regulatory positions 4.a.(l),4.a.(2), and 4.a.(3). The design limits of NB-3222 areselected because the primary stress intensities associatedwith those limits are in the elastic range and thus providegreater assurance of operability for pumps and valves(i.e., less probability of unacceptable deformations thatwould impede or prevent operation) than the designlimits for the upset, emergency, and faulted operatingcondition categories of Section Ii. Secondary effects(stresses and deformations,) in components whosc function is pressure retention are not usually evaluatedfor the loading combinations delineated in regulatorypositions '4.a.(2) and 4.a.(3). However, these effectsshould be considered for active Class I pumps and valvesso that unacceptable' deformations do not result. Localeffects (peak stresses) 'need not be evaluated for theseloading combinations. In addition to compliance withthe design limits specified, demonstration of operabilityas outlined by Note 6 to the regulatory position shouldalso be provided. Note 6 suggests appropriate testing,analysis, or combinations of those measures that shouldbe implemented to demonstrate the operability of activepumps and valves under all design loadinig'combinations.However, Note 6 states that the design limits fornon-active pumps and valves designed by analysis may beused if assurance is provided by detailed stress anddeformation:analyses that operability is not impairedwhen designed to these limits.Active ASME Code Class 1 Valves (Designed byStandard or Alternative Design Rules)To provide greater assurance of operability, theprimary pressure rating (Pr) for Code Class 1 activevalves designed by standard or alternative rules shouldnot be exceeded when the valve is subjected to thecombination of loadings delineated in regulatorypositions 5.a.(1), 5.a.(2), and 5.a.(3). This design limit isselected on the same basis as that designated for activepumps and valves that are designed by analysis and isanalogous to design limits specified for the normaloperating condition category of Section III of the ASMECode. Note 6 to the regulatory position also applies.However, in the case of pressure-related valves, Note 6states that the primary-pressure ratings (Pr) fornon-active valves designed by standard or alternativedesign rules may be used for the applicable loadingcombinations if appropriate testing demonstrates thatoperability is not impaired when the valve is so rated.Since detailed analytical techniques are not used todesign pressure-temperature rated valves, demonstrationof operability by test is'indicated.ASME Code Class 2 and 3 ComponentsWith one exception, no distinction is made betweenCode Class 2 and 3 components since the designrequirements of Section III of the ASME Code are thesame for both classes of components. The design rulesfor Code Class 2 and 3 components do not provide fordesign by analysis (except for Code Class 2 vesselsdesigned in accordance with Section VIII, Division 2, ofthe ASME Code) and do not yet provide any design rulesfor pumps. Furthermore, no design limits for other thanthe normal plant condition are available (the oneexception to this is piping). Generally, Class 2 and 3components are of somewhat lower quality as related t0'material, fabrication, and. nondestructive examinationrequirements than Code Class I components. Because ofless stringent design requirements and a lower qualitylevel in comparison to Code Class 1 components; thedesign limits selected for Code Class 2 and 3 non-activecomponents are, on a comparable basis, lower for thecombination of loadings associated With the emergencyand faulted plant conditions than for Code Class 1non-active components. The same considerations thatapply to Code Class I active pumps and valves apply toCode Class 2 and 3 active pumps and valves.ASME Code Class 2 and 3 Vessels (Designed to Division1 of Section VIii)To provide assurance of pressure-retaining integrityfor Code Class 2 and 3 vessels, the allowable stress valueS should not be exceeded by more than 10 percent forthe combination of loadings delineated' in 'regulatorypositions 6.a.(1), and 6.a.(2), and S should not beexceeded by more than 50 percent-for the combination1.48-3, of loadings specified by regulatory position 6.b. Onehundred ten percent of S is analogous to the upsetoperating condition category design limitsspecified forCode Class I components, while 150 percent of S iscomparable to the membrane stress that would occur ina cylindrical or spherical shell during hydrostatic testing.Both limits are within the elastic stress range for ferriticmaterials. If a more detailed analysis is performed. noloe9 to the regulatory position provides limits for prinoarymembrane and primary bending stresses.ASME Code Class 2 Vessels (Designed to Division 2 ofSection VIII)Section III of the ASME Code allows Code Class 2vessels to be designed in accordance with the rules ofDivision 2 to Section VIII of the ASME Code. Division 2to Section VIII provides rules for design by analysis thatare equivalent to those of Section III for Code Class Ivessels. In addition, the quality level for Division 2vessels is comparable to that for Code Class I vessels ofSection III. Therefore, the design limits for the loadingcombinations delineated in regtilatory position 7. shouldbe tile same as those for Code Class I vessels inregulatory position I.ASME Code Class 2 and 3 PipingNC-3600 of Section ill of the ASME Code land byreference ND-3600) provides design limits for pipingunder "Upset Conditions" and "Emergency Conditions"which are analogous to tile upset and emergencyoperating condition category design lilmits specified inNB-3600 for Code Class I piping. In utilizing thesedesign limits'for assurance of pressure-retaining integrity,the "Upset Condition" limits should not be exceeded forthe combination of loadings delineated in regulatorypositions 8.a.(I), and 8.a.(2). and the "EmnergencyCondition" limits should not be exceeded for thecombination of loadings specified in regulatory position8.b. However, only equation 9 of NC-3651 need he metfor the loadings designated in regulatory position 8.a.(2)since thermal expansion effects of piping are not usuallyevaluated for these loadings.Non-Active ASME Code Class 2 and-3 PumpsDesign limits were selected for Code Class 2 and 3pumps in the absence of Section III of the ASME Codedesign rules for these components. These design limitsrelate to both primary membrane and primary bendingstresses~and are derived on a basis that is comparable tothe design limits for Code Class I components designedby analysis. One hundred ten percent of S and 120percent of S (and the limilts for primary membrane plusprimary bending) are analogous to the design limits forthe upset operating condition category and theemergency operating condition category, respectively,given in NB-3200 of Section 11I. Therefore, to assurepressure-retaining integrity, the primary membrane stressshould not be exceeded by more than 10 percent of S,and the sumn of the primary membrane plus primarybending stresses should not be exceeded by more than65 percent of S for the combination of loadingsdelineated in regutlatory positions 9.a.(]), and '9.a.(2).The primary membrane stress and thfe surn of theprimary membrane plus primary bending stresses shouldnot be exceeded by nlore than 20 percent and 80percent of S. respectivel'. for the combination ofloadings delilneated in regulatory position 9.b.Active ASME Code Class 2 and 3 PumpsFor active Code Class 2 and 3 pumps the primaryllemllbrane stress should not exceed S. and tile surnof the primary membrane plus primary bending stressesshould not be exceeded by more than 50 percentof S fbr the combination of loadings delineated inregulatory positions 10.a.( I ), 10.a.(2), and 10.a.(3).These limits are analogous to tile normal operatingcondition category design limits of NB-3200 of SectionIll of the ASME Code and thus provide increasedassurance that unacceptable deformations affectingoperability of active Code Class 2 and 3 pumps will notresult. In addition to compliance with the design limitsspecified. demonstration- of operability as outlined byNote I1 to tl1e reCulatory position should also beprovided. Note II is identical to Note 6 to theregulatory position except that the design limits fornon0-active pumps and valves may be used for theapplicable loading combinations if appropriate analysesand/or testing confirnms that operability will not beimpaired when the component is designed to theselimits.Non-Active ASME Code Class 2 and 3 ValvesThe design of Co de Class 2 and 3 valvesencompasses the use of pressure-temllperature ratings.The design limits (Oven herein are in terms of Pr which isthe prinlary-pressure rating corresponding to themaximunm transient temperature for each plantcondition as specified in NC-3511 and ND-351 I forCode Class 2 and 3 valves, respectively. This definition'of Pr differs froim the Section III of the ASME Codeof Pr in tile same manner 'as that for CodeClass I valves and the same considerations apply. Toassure pressure-retainiung integrity, the limits for Pr arelower than those given for Code Class 1 valves for thesame loading combinationis involving emergency andfaulted plant conditions. Pr should n6t be exceeded bymore than 10 percent for the combination of loadingsdelineated in regulatoiy positions I i.a.(1), and I l.a.(2),and Pr should not be exceeded by more than 20 percentfor the combination of loadings delineated in regulatoryposition 1I .b.Active ASME Code Class 2 and 3 ValvesTo provide greater assurance of operability foractive valves of Code Class 2 and 3, Pr should not beexceeded for the comnbination of loadings delineated in -regulatory positions 12.a,(i), 12.a.(2), and 12.a.(3).Note I I to ,ie regulatory position applies. However, asI .48-4 allowed! by' Note 11, if the design limits for non-activevalves are used, appropriate testing should demonstrateoperability in lieu of analysis since detailed analyticaltechniques are. not applied to designpressure-temperature rated valves.C. REGULATORY POSITIONSeismic Category I fluid system components shouldbe designed to withstand the following loadingcombinations within the design limits ' specified.1. ASME Code2.Class 1 vessels and piping:a. The design limits specified in NB-3223 andNB-3654 of the ASME Code for vessels and piping,respectively, should not be exceeded when thecomponent is subjected to concurrent loadingsassociated with either the normal plant condition or theupset plant condition3 and the vibratory motion of 50percent of the Safe Shutdown Earthquake (SSE).b. The design limits specified in NB-3224 andNB-3655 of the ASME Code for vessels and piping,respectively, should not be exceeded when thecomponent is subjected to loadings associated with theemergency plant condition.c. The design limits specified in NB-3225 andNB-3656 of the ASME Code for vessels and piping,respectively, should not .'be exceeded when thecomponent is subjected to concurrent loadingsassociated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.2. Non-active ASME Code Class 1 pumps and valves4that are designed by analysis:a. The design limits specified in NB-3223s of theASME Code should not be exceeded when thecomponent is subjected to concurrent loadingsassociated with either the normal plant condition or theupset plant condition and the vibratory motion of 50percent of the SSE.b. The design limits. specified in NB-3224 of theASME Code should not be exceeded when thecomponent is subjected to loadings associated with theemergency plant condition.c. The design limits specified in NB-3225 of tileASME Code should not be exceeded when thecomponent is subjected to concurrent loadingsassociated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.3. Non-active ASME Code Class 1 valves that aredesigned by standard or alternative design rules:a. The primary-pressure rating Pr should not beexceeded by more than 10 percent when the componentis subjected to concurrent loadings associated with eitherthe normal plant condition or the upset plant conditionand the vibratory motion of 50 percent of the SSE.b. Pr should not be exceeded by more than 20percent when the component is subjected to the loadingsassociated with the emergency plant condition.c. Pr should not be exceeded by more than 50percent when the component is subjected to concurrentloadings associated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.4. Active ASME Code Class 1 pumps and valves4 thatare designed by analysis:a. The design limits6 specified in NB-32225 7,8 ofthe ASME Code should not be exceeded when thecomponent is subjected to either (1) concurrent loadingsassociated With either the normal plant condition or theupset plant condition and the vibratory motion of 50percent of the SSE, or (2) loadings associated with'theemergency plant condition, or (3) concurrent loadings"associated with the normal plant condition, the'vibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.5. Active ASME Code Class 1 valves that are designedby standard or alternative design rules:a. The primary-pressure rating Pr6 should not be'exceeded when the component iý subjected to either (1)concurrent loadings associated with either the normalplant condition or the upset plant condition and the'vibratory motion of 50 percent of the SSE, or (2)loadings associated with the emergency plant condition,or (3) concurrent loadings associated with the niormal'plant condition, the vibratory motion of the SSE, and'the dynamic system loadings associated with the faulted'plant condition.6. ASME Code Class 2 and 3 vessels 'designed to.Division 1 of Section VIII of the ASME Code:a. The allowable stress value S9 should not beexceeded by, more than 10 percent when the componentis subjected to either (1) concurrent loadings associated.with either the normal plant condition or the upset plantcondition and the vibratory motion of 50 percent of the..SSE, or (2) loadings associated with the emergency plantcondition.b. S should not be exceeded by more than 50percent when the component is subjected to concurrentloadings associated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.7. ASME Code Class 2 vessels designed to Division 2 ofSection VIII of the ASME Code:a. The design limits specified in NB-3223 of theASME Code should not be exceeded when thecomponent is subjected to concurrent loadingsassociated with either the normal plant condition or theupset plant condition and the vibratory motion of 50percent of the SSE.1.48-5 b. The design limits specified in NB-3224 of theASME Code should not be exceeded when thecomponent is subjected to loadings associated with theemergency plant condition.c. The design limits specified in NB-3225 of theASME Code should not be exceeded when thecomponent is subjected to concurrent loadingsassociated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.8, ASME Code Class 2 and 3 piping:a. The design limits specified inNC-361 1.1(b)(4)(c)(b)(1) of the ASME Code should notbe exceeded when the component is subjected to either(1) concurrent loadings associated with either thenormal plant condition or the upset plant condition andthe vibratory motion of 50 percent of the SSE, or (2)"0loadings associated with the emergency plant condition.b. The design limits specified inNC-361 1 .1(bX4Xc)(b)(2) of the ASME Code should notbe exceeded when the component is subjected toconcurrent loadings associated with the normal plantcondition, the vibratory motion of the SSE, and thedynamic system loadings associated with the faultedplant condition.9. Non-active ASME Code Class 2 and 3 pumps:a. The primary membrane stress should not beexceeded by more than 10 percent of the allowablestress value S, and the sum of the primary membraneand primary bending stresses should not be exceeded bymore than 65 percent of S when the component issubjected to. either (1) concurrent loadings associatedwith either the normal plant condition or the upset plantcondition and the vibratory motion of 50 percent of theSSE, or (2) loadings associated with the emergency plantcondition.b. The primary membrane stress should not beexceeded by more than 20 percent of S, and the sum ofthe primary membrane and primary bending stressesshould not be exceeded by more than 80 percent of Swhen the component is subjected to concurrent loadingsassociated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.10. Active ASME Code Class 2 and 3 pumps:a. The primary membrane stress should notexceed the allowable stress value S, and the sum of theprimary membrane and the primary bending stresses'should not be exceeded by more than 50 percent of Swhen the component is subjected to either (1)concurrent loadings associated with either the normalplant condition or the upset plant condition and thevibratory motion of 50 percent of the SSE, or (2)loadings associated with the emergency plant condition,or (3) concurrent loadings associated with the normalplant condition, the vibratory motion of the SSE, andthe dynamic system loadings associated with the faultedplant condition.11. Non-active ASME Code Class 2 and 3 valves:a. The primary-pressure rating Pr should not beexceeded by more than 10 percent when the componentis subjected to either (1) concurrent loadings associatedwith either the normal plant condition or the upset plantcondition and the vibratory motion of 50 percent of theSSE, or (2) loadings associated with the emergency plantcondition.b. Pr should not be exceeded by more than 20percent when the component is subjected to concurrentloadings associated with the normal plant condition, thevibratory motion of the SSE, and the dynamic systemloadings associated with the faulted plant condition.12. Active ASME Code Class 2 and 3 valves:a. The primary-pressure rating Pr1' should not beexceeded when the component is subjected to either (1)concurrent loadings associated with either the normalplant condition or the upset plant condition and thevibratory motion of 50 percent of the SSE, or (2)loadings associated with the emergency plant condition,or (3) concurrent loadings associated with the normalplant condition, the vibratory motion of the SSE, andthe dynamic system loadings associated with the faultedplant condition.01.48-6 DEFINITIONSActive Pumps and Valves. Components that mustperform a mechanical motion during the course ofaccomplishing a system safety function.Allowable Stress Value (S). As specified in Appendix Iof Section III of the ASME Boiler and Pressure VesselCode.Design by analysis for Class 1 Pumps and Class 1 Valves.For Class 1 pumps, the design procedures specified inNB-3200 of the ASME Boiler and Pressure Vessel Code,Section III. For Class, I valves, the requirements of Case1552 of Interpretations of ASME Boiler and PressureVessel Code.Dynamic System Loadings Associated with the FaultedPlant Condition. Refers to those dynamic loadings whichresult from the occurrence of a postulated rupture (e.g.,complete severance or equivalent longitudinal breakarea) of any reactor coolant pressure boundary piping orof any other piping not a part of the reactor coolantpressure boundary.Emergency Plant Condition. Those operating conditionswhich have a low probability of occurrence.Faulted Plant Condition Those operating conditionsassociated with extremely-low-probability postulatedevents.Normal Plant Condition. Those operating conditions inthe course of system startup, operation, hot standby,and shutdown other than upset, emergency, or faulted.plant conditions.Plant Conditions. Operating conditions of the plantcategorized as normal, upset, emergency, and faulted.plant condtions.Primary-Pressure Rating (Pr). The primary-presstirerating corresponding to the maximum transienttemperature for each plant condition, as specified inSection III of the ASME Boiler and Pressure VesselCode, Tables NB-3531-1 to NB-3531-7, for Code Class 1-valves or as specified in NC-3511 and ND-3511 for CodeClass 2 and 3 valves, respectively.Safe Shutdown Earthquake (SSE). That earthquakewhich produces the vibratory ground motion for whichstructures, systems, and components important to safetyare designed to remain functional.Seismic Category I. Those structures, systems, andcomponents that are designed to remain functional if theSSE occurs.Standard or Alternative Design Rules for Class 1 Valves.As specified in NB-3512 and NB-3513 of the ASMEBoiler and Pressure Vessel Code,Section III.Upset Plant Condition. Those deviations from thenormal plant condition which have a high probability ofoccurrence.NOTESb. full-scale prototype testing.c. reduced-scale prototype testingd. detailed stress and deformation analyses (includesexperimental stress and deformation analyses).In the performance of tests or analyses to demonstrateoperability, the structural interaction of the entire assembly(e.g., valve-operator assembly and pump-motor assembly) shouldbe considered. If superposition of test results for other than thecombined loading condition is proposed, the applicability ofsuch a procedure should be demonstrated. The design limits fornon-active pumps and valves designed by analysis may be usedfor the applicable loading combinations if assurance is providedby detailed stress and deformation analyses that operability isnot impaired when designed to these limits. Similarly, theprimary-pressure ratings Pr for non-active valves designed bystandard or alternative design rules may be used for theapplicable loading combinations if appropriate testingdemonstrates that operability is not impaired when the valve isso rated.7Secondary effects (stresses and deformations) should beevaluated for the loading combinations designated by regulatorypositions 4.a.(2) and 4.a.(3). Local effects (peak stresses) neednot be considered for these loading combinations.Applies to all components (vessels, piping, pumps, andvalves) that are relied upon to cope with the effects of specifiedplant conditions.2Section III of the American Society of MechanicalEngineers Boiler and Pressure Vessel Code including the 1972Winter Addenda thereto.'Identification of the specific transients or events to beconsidered under each plant condition will be addressed in afuture regulatory guide.4The requirements of the Case 1552 (Interpretations ofASME Boiler and Pressure Vessel Code) should be met for allsizes of Code Class 1 valves designed by analysis.'The provisions of NB-3411 and NB-3413 may be appliedfor all sizes of Code Class 1 pumps designed by analysis.6'Inaddition to compliance with the design limits specified,assurance of operability under all design loading combinationsshould be provided by an appropriate combination of thefollowing suggested measures:a. in situ testing (e.g., preoperational testing after thecomponent is installed in the plant).1.48-7 I8Table 1-3.0, "Permanent Strain Limiting Factors," ofAppendix I of the ASME Boiler and Pressure Vessel Code,Section III, may be used as an aid in determining the relationshipbetween design stress and deformation (see note 2 to Table 1-1.2,of Sectiori Ill of the ASME Code).9Division 1 of Section VIII of the ASME Boiler andPressure Vessel Code does not provide rules for design byanalysis. If a detailed analysis is performed, Division 1 vesselsshould meet, as a minimum, equations a and b below. which arcapplicable to regulatory positions 6.a. and 6.b., respectively.a. om < 1.IS > m +Ob1.5b. am < 1.5S > Om +o bin 1.5where:urn = primary membrane stress;ob = primary bending stress;S = allowable stress value as specified in Appendix I ofSection III of the ASME Boiler and Pressure Vessel Code." For the loadings designated in regulatory position 8.a.(2),onlyequation 9 of NC-3651 need be met.In addition to compliance with the design limits qspecified, assurance of operability under all design loadingcombinations should be provided by any appropriatecombination of the following suggested measures:a. in situ testing (e.g., preoperational testing after thecomponent is installed in the plant).b. full-scale prototype testing.c. reduced-scale prototype testing.d. detailed stress and deformation analyses (includesexperimental stress and deformation analyses).In the performance of tests or analyses to demonstrateoperability, the structural interaction of the entire assembly(e.g., valve-operator and pump-motor assembly) should beconsidered. If superposition of test results for other than thecombined loading condition is proposed, the applicability ofsuch a procedure should be demonstrated. The design limits fornon-active pumps and valves may be used for the applicableloading combinations if appropriate analyses and/or testingcooifirms that operability is not impaired when designed to theselimits.1.48-8