Regulatory Guide 1.61: Difference between revisions

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{{#Wiki_filter:Structures, systems, and components of a nuclear power plant that are designated as Seismic Category I are designed1to withstand the effects of the safe shutdown earthquake (SSE) and remain functional, see Regulatory Guide 1.29,"Seismic Design Classification."Appendix S to 10 CFR Part 50 applies to applicants for a design certification or combined license pursuant to210 CFR Part 52, "Early Site Permits; Standard Design Certifications; and Combined Licenses for Nuclear Power Plants,"or a construction permit or operating license pursuant to 10 CFR Part 50 after January 10, 1997However, for eitheran operating license applicant or holder whose construction permit was issued before January 10, 1997, the earthquakeengineering criteria in Section VI of Appendix A to 10 CFR Part 100 continue to apply.The U.S. Nuclear Regulatory Commission (NRC) issues regulatory guides to describe and make available to the public methods that the NRC staffconsiders acceptable for use in implementing specific parts of the agency's regulations, techniques that the staff uses in evaluating specific problemsor postulated accidents, and data that the staff need in reviewing applications for permits and licensesRegulatory guides are not substitutesfor regulations, and compliance with them is not requiredMethods and solutions that differ from those set forth in regulatory guides will be deemedacceptable if they provide a basis for the findings required for the issuance or continuance of a permit or license by the Commission.This guide was issued after consideration of comments received from the public.  The NRC staff encourages and welcomes comments and suggestionsin connection with improvements to published regulatory guides, as well as items for inclusion in regulatory guides that are currently being developed. The NRC staff will revise existing guides, as appropriate, to accommodate comments and to reflect new information or experienceWritten commentsmay be submitted to the Rules and Directives Branch, Office of Administration, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.Regulatory guides are issued in 10 broad divisions:  1, Power Reactors; 2, Research and Test Reactors; 3, Fuels and Materials Facilities;4, Environmental and Siting; 5, Materials and Plant Protection; 6, Products; 7, Transportation; 8, Occupational Health; 9, Antitrust and Financial Review;and 10, General.Requests for single copies of draft or active regulatory guides (which may be reproduced) should be made to the U.S. Nuclear Regulatory Commission,Washington, DC 20555, Attention: Reproduction and Distribution Services Section, or by fax to (301) 415-2289; or by email to Distribution@nrc.gov. Electronic copies of this guide and other recently issued guides are available through the NRC's public Web site under the Regulatory Guides documentcollection of the NRC's Electronic Reading Room at http://www.nrc.gov/reading-rm/doc-collections/ and through the NRC's Agencywide DocumentsAccess and Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html, under Accession No. ML070260029.U.S. NUCLEAR REGULATORY COMMISSION
{{#Wiki_filter:Stru ctures, sy stem s, and com po nent s of a nuclear pow er plant th at are designated as Seism ic Cate gory I are designed 1 to w iths ta nd the e f f ec ts of the s af e shut dow n e ar thqua k e (SS E) and re m ai n f unct iona l, se e Re g ula tory G uide 1.29,"S ei sm ic D es ig n Cl as si f ic at ion."A ppendi x S t o 10 C FR Part 50 a pplie s to a pplic ant s f or a de si g n c er tif ic at ion or c om bine d li ce nse purs uant to 2 10 CF R Par t 52, "Ea rly Sit e Perm its; St anda rd D es ig n Ce rti f ic at ions; a nd Com bine d L ic ens es f or N ucl ea r Pow er Plant s,"or a constru ction perm it or op erating license pu rsuant to 10 CFR P art 50 af ter Ja nu ary 10, 199 7Howe ver, f or either an op era ti n g li cen se ap p li can t o r h o ld er who se co n st ru ct io n pe rmit w as i ssu ed be for e Jan u ary 10 , 1 9 9 7 , t h e ear th q u ake e n g i n e e r i n g c r i t e r i a i n S e c t i o n V I o f Ap p e n d i x A t o 1 0 C F R P a r t 1 0 0 c o n t i n u e t o a p p l y.T h e U.S. N u c le a r R e g u la to ry C o m m is s io n (N R C) i s s u e s re g u la to ry g u id e s to d e s c rib e a n d m a k e a v a il a b le to th e p u b li c m e th o d s th a t t h e N R C s ta ff con si der s acc ept abl e f or us e i n i m pl em ent i ng spe ci f i c par t s of t he age ncy's r egu l at i ons , t ech ni que s t hat t he st af f us es i n e val uat i ng spe ci f i c pr obl em s or po st ul at ed acc i den t s, an d d at a t hat t he st af f ne ed i n r evi ewi ng app l i cat i ons f or pe r m i t s and l i cen sesRegul at or y gu i des ar e n ot s ubs t i t ut es f or r egu l at i ons , an d c om pl i anc e wi t h t hem i s not r equ i r edMet hod s and s ol ut i ons t hat di f f er f r om t hos e s et f or t h i n r egu l at or y gu i des wi l l be de em ed acc ept abl e i f t hey pr ovi de a b asi s f or t he f i ndi ngs r equ i r ed f or t he i ss uan ce or c ont i nua nce of a per m i t or l i cen se by t he C om m i ss i on.T hi s gui de was i ss ued af t er c ons i der at i on of c om m ent s r ece i ved f r om t he pub l i c.  The N R C s t af f en cou r age s and wel com es com m ent s and s ugg est i ons in c o n n e c ti o n w it h i m p ro v e m e n ts to p u b li s h e d re g u la to ry g u id e s , a s w e ll a s i te m s fo r i n c lu s io n i n re g u la to ry g u id e s th a t a re c u rre n tl y b e in g d e v e lo p e d. T h e N R C s ta ff w il l re v is e e xis ti n g g u id e s , a s a p p ro p ria te , t o a c c o m m o d a te c o m m e n ts a n d to re fl e c t n e w i n fo rm a ti o n o r e xp e rie n c eW rit te n c o m m e n ts m ay be s ubm i t t ed t o t he R ul es and D i r ect i ves Br anc h, O f f i ce of Adm i ni st r at i on, U.S. N ucl ear R egu l at or y C om m i ss i on, W ash i ngt on, D C 20 555-000 1.R egul at or y gui des ar e i ssued i n 10 br oad di vi si ons:  1, P ow er R eact or s; 2, R esear ch and T est R eact or s; 3, Fuel s and M at er i al s Faci l i t i es;4, Env i r on m en t al a nd Si t i ng; 5 , Ma t er i al s a nd Pl an t Pr ot ec t i on; 6 , Pr od uc t s; 7 , Tr an s po r t at i on; 8 , Occ up at i on al Hea l t h; 9 , Ant i t r us t a nd F i na nc i al Rev i ew;a n d 1 0 , G e n e ra l.R equ est s f or s i ngl e c opi es of dr af t or ac t i ve r egu l at or y gu i des (whi ch m ay be r epr odu ced) s hou l d b e m ade t o t he U.S. N ucl ear R egu l at or y C om m i ss i on, W ash i ngt on, D C 20 555 , At t ent i on: R epr odu ct i on and D i st r i but i on S er vi ces Sect i on, or by f ax t o (301) 41 5-228 9; or by em ai l t o D i st r i but i on@nr c.gov. E l ect r oni c cop i es of t hi s gui de and ot her r ece nt l y i ss ued gu i des ar e a vai l abl e t hr oug h t he N R C's pub l i c W eb si t e u nde r t he R egu l at or y G ui des do cum ent c o ll e c ti o n o f t h e N R C's E le c tro n ic R e a d in g R o o m a t ht t p://w w w.nr c.gov/r eadi ng-r m/doc-col l ect i ons/ a n d th ro u g h th e N R C's A g e n c yw id e D o c u m e n ts A c c e s s a n d M a n a g e m e n t S ys te m (A D A M S) a t h ttp://w w w.n rc.g o v/re a d in g-rm/a d a m s.h tm l, un der Acces si on N o. ML0702 600 29.U.S. N UC LEA R RE GU LA TO RY C OM MI SSIO N
March 2007Revision 1REGULATORY GUIDEOFFICE OF NUCLEAR REGULATORY RESEARCHREGULATORY GUIDE 1.61(Draft was issued as DG-1157, dated October 2006)DAMPING VALUES FOR SEISMIC DESIGNOF NUCLEAR POWER PLANTS
M ar ch 2007 R ev i si on 1 RE GUL AT ORY GUI DE OFFICE OF NUCL
EA R REGULA TORY RESEA RCH R E G U LA TO R Y G U I D E 1.61 (D r af t w as i ssued as DG-1157, dat ed O ct ober 200 6)DA MPI NG VA L UE S F OR SE I SMI C D ES I GN O F N U C LE A R P O W E R P LA N TS A.  INT ROD UC TIONThis reg ulatory g uide is bein g rev ised to up date th e g uidanc e for applican ts and licens ees reg arding the acceptab le dam ping v alues that the U.S. N uclear Reg ulatory C om m ission (NR C) staff use d in the seism ic resp onse analy sis of Seism ic C ateg ory I nu clear p owe r plan t structu res, sy stem s, 1 and com pone nts (S SC s) in accord ance with Title 10, Part 5 0, of the Cod e of Fede ral R egulatio ns (1 0 C F R P ar t 5 0), "D om es ti c L ic en si ng o f P ro du ct io n an d U ti li z at io n F ac il it ie s" [R ef. 1].Spec ifically , G eneral Desig n C riterion 2 , "Desig n B ases fo r Pro tection Ag ainst N atural P heno m ena,"of A ppen dix A , "Gen eral D esig n C riteria for Nuc lear P owe r Plan ts," to 10 C FR Pa rt 50 requires that SSC s im portant to safe ty be desig ned to w ithstand the effe cts of natural phen om ena such as ea rthquak es witho ut los ing the ability to perform their safety fun ctions.  S uch SSC s m ust also be desig ned to a cc om m od at e th e ef fe ct s of a nd b e co m pa ti bl e w it h th e en v ir on m en ta l c on di ti on s as so ci at ed w it h norm al op eration and postula ted ac cidents.  A ppen dix S , "Earthq uak e E ng ineering C riteria for Nuc lear Po we r Pl a nt s ," to 10 CFR Pa r t 50 sp e c i f i e s th e re qu i r e men t s fo r th e impl e men t a t i on of Ge ne r a l De s i gn Criterion 2 with respect to earth quak es.2 Rev. 1 of RG 1.61, Pa g e 2Thi s re g ul at or y g ui de s pe ci fi es th e da m pi ng v al ue s th at th e N R C s ta ff c on si de rs a cc ep ta bl e for co m ply ing w ith the ag ency's reg ulations and g uidanc e for seism ic ana ly sis.  The sp ecified dam ping v alues are inte nded for elastic m odal dy nam ic seism ic ana ly sis w here energ y dissip ation is acco unted for by v is co us d am pi ng (i.e., th e da m pi ng f or ce is p ro po rt io na l t o th e v el oc it y).Thi s re g ul at or y g ui de c on ta in s in fo rm at io n co ll ec ti on s th at a re c ov er ed b y th e re qu ir em en ts of 1 0 C FR Pa rt 50, w hich the O ffice of Manag em ent an d B udg et (O MB) a pprov ed u nder OMB con trol num ber 3 150-0011.  The NR C m ay neith er co nduc t nor spon sor, and a pe rson is no t requ ired to respo nd to, an in fo rm at io n co ll ec ti on r eq ue st o r re qu ir em en t u nl es s th e re qu es ti ng d oc um en t d is pl ay s a cu rr en tl y v al id O MB c on tr ol n um be r.B.  DISC US SION Bac kgr oundD am pi ng is a m ea su re o f th e en er g y d is si pa ti on o f a m at er ia l o r st ru ct ur al s y st em a s it r es po nd s to dy nam ic exc itation.  I t is a term use d to assist in m athem atically m odeling and solv ing dy nam ic equ ations of m ot io n fo r a v ib ra to ry s y st em in w hi ch e ne rg y is d is si pa te d.  W he n pe rf or m in g a n el as ti c dy na m ic seism ic ana ly sis, one can accou nt for the en erg y dissip ated b y spe cify ing the am ount of v iscous dam ping (i.e., d am pi ng f or ce p ro po rt io na l t o th e v el oc it y) in th e an al y ti ca l m od el.C ur re nt N R C g ui da nc e on d am pi ng v al ue s to b e us ed in th e el as ti c de si g n of n uc le ar p ow er p la nt s is pres ented in this reg ulatory g uide, w hich was first issued in Octo ber 1 973 [Ref. 2].  L ik e the orig inal ver s i on of th i s gui de , t hi s re vis i on sp e c i f i e s eq ui val e nt vis c ou s m od a l da mpi ng val ue s as a p e r c e nt a ge of critical dam ping for Seism ic C ateg ory I SS Cs.  H owe v er, the sta ff base d the orig inal d am ping v alues on li m it ed da ta , expe rt opin ion , and ot her inf ormati on avail abl e in 19 73.  Sinc e tha t ti m e, th e NRC an d in du st ry h av e be en in v ol v ed in v ar io us s tu di es , r es ea rc h w or k , a nd te st in g to p re di ct a nd e st im at e dam ping v alues of S SC s.  I n v iew of the av ailable d ata, the d am ping v alues prov ided in the orig inal v ersion of R eg ulatory G uide 1.6 1 m ay no t reflect realistic da m ping v alues for S SC s.  A lso, it is rec og niz ed that ad ditional g uidanc e is neede d to address issue s, such as co rrelation betw een dam ping and structu res stress lev el, a nd dam ping v alues for m aterials n ot inc luded in the orig inal v ersion of R eg ulatory G uide 1.6 1 (e.g., e le ct ri ca l d is tr ib ut io n sy st em s an d re in fo rc ed m as on ry s tr uc tu re s).Ov er the past th ree d ecades , th e nu clear in dustry has pro posed dam ping v alues and discuss ed these v alues during v arious m eeting s an d rev iews of licen sing issue s.  N uclear industry g roups and licensees ha v e su g g es te d th at th e N R C o ug ht to a cc ep t m or e re al is ti c da m pi ng v al ue s fo r se is m ic d es ig n an d an al y si s of S SC s, in pla ce o f the dam ping v alues prov ided in the orig inal R eg ulatory G uide 1.6 1.St r uc tu r al D am pingI n 1 993, the NR C com pleted an in v estig ation of the ade quacy of orig inal R eg ulatory G uide 1.6 1 structure dam ping v alues and other recom m endatio ns, and reported the results in N UR EG/CR-6011 [R ef. 3]. Data were analy z ed to iden tify the param eters tha t sig nificantly influe nced structure dam ping.  Base d o n t ha t st ud y, t he NRC de t e r min e d t ha t th e or i gin a l Re gul a t or y Gui de 1.61 da mpi ng val ue s fo r st r uc t ur e de s i gn were adequ ate bu t requ ired o ne s ig nificant rev ision.  S pecifically , R eg ulatory G uide 1.6 1 sh ould disting uish betw een "friction- bolted" and "be aring-bolted" con nection s for steel stru ctures.  F riction-bolted conn ections a r e al s o r e f e r r e d t o a s "s l i p-cr i t i c a l" co nn e c t i on s.  I n t he s e co nn e c t i on s , t he bo l t pr e l oa d i s hi gh e no ugh to e ns ur e th at f ri ct io n is n ot o v er co m e, a nd th e bo lt d oe s no t e xp er ie nc e sh ea r lo ad in g.  R eg ul at or y Position 1 in S ection C of this rev ised g uide prov ides th e up dated structural dam ping v alues.


==A. INTRODUCTION==
Rev. 1 of RG 1.61, Pa g e 3 P iping Da m pingI n 1 986, the Am erican Society of Mechanica l En g ineers (AS ME) esta blished C ode Case N-411,"A l t e r n a t i ve Da mp i n g V a l u e s f o r Re s p o n s e Sp e c t r a An a l ys i s o f Cl a s s 1 , 2 , a n d 3 Pi p i n g," i n Se c t i o n I II , Div ision 1, of the A SME Boiler and Pressu re Vessel C
This regulatory guide is being revised to update the guidance for applicants and licenseesregarding the acceptable damping values that the U.S. Nuclear Regulatory Commission (NRC) staff usedin the seismic response analysis of Seismic Category I nuclear power plant structures, systems,1and components (SSCs) in accordance with Title 10, Part 50, of the Code of Federal Regulations(10 CFR Part 50), "Domestic Licensing of Production and Utilization Facilities" [Ref. 1].Specifically, General Design Criterion 2, "Design Bases for Protection Against Natural Phenomena,"of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50 requires thatSSCs important to safety be designed to withstand the effects of natural phenomena such as earthquakeswithout losing the ability to perform their safety functionsSuch SSCs must also be designedto accommodate the effects of and be compatible with the environmental conditions associated withnormal operation and postulated accidentsAppendix S, "Earthquake Engineering Criteria for NuclearPower Plants," to 10 CFR Part 50 specifies the requirements for the implementation of General DesignCriterion 2 with respect to earthquakes.2 Rev. 1 of RG 1.61, Page 2This regulatory guide specifies the damping values that the NRC staff considers acceptablefor complying with the agency's regulations and guidance for seismic analysisThe specified dampingvalues are intended for elastic modal dynamic seismic analysis where energy dissipation is accounted forby viscous damping (i.e., the damping force is proportional to the velocity).This regulatory guide contains information collections that are covered by the requirementsof 10 CFR Part 50, which the Office of Management and Budget (OMB) approved under OMB controlnumber 3150-0011The NRC may neither conduct nor sponsor, and a person is not required to respond to,an information collection request or requirement unless the requesting document displays a currentlyvalid OMB control number.
ode [Ref. 4].  The NR C staff use d C ode Case N-411, with certain lim itations specified in R eg ulatory G uide 1.8 4 [R ef. 5], to rev iew operatin g reacto r issue s until C ode Case N-411 expired in 2000.  The staff also app rov ed th e us e of alternate dam ping v alues for the G eneral Electric Adv anced B oiling Water R eactor Desig n in 1994 [R ef. 6], Com bustion En g ineering S y st em 8 0+ D es ig n in 1 99 2 [R ef. 7], a nd We st in g ho us e A P 60 0 D es ig n in 1 99 8 [R ef. 8].  R eg ul at or y Position 2 in S ection C of this rev ised g uide prov ides th e pip ing dam ping v alues that resu lted from the sta ff's exp erience with AS ME C ode Case N-411 and app lication rev iews of n ew reactor desig ns.Ele c tr ic al D ist r ibut ion Sys te m Da m pingReg ulatory G uide 1.6 1 d id no t orig inally pro v ide d am ping v alues for cab le tray or cond uit sy stem s. H is to ri ca ll y , th e nu cl ea r po w er in du st ry u se d th e da m pi ng v al ue s fo r bo lt ed s te el s tr uc tu re s fo r se is m ic de si g n of c ab le tr ay a nd c on du it s y st em s.  I n th e la te 1 98 0s , h ow ev er , th e N R C s ta ff r ev ie w ed th e re su lt s of the cab le tray test at the Com anche Pe ak Stea m Ele ctrical S tation [R ef. 9]R eg ulatory Po sition 3 in S ection C of this rev ised g uide prov ides th e da m ping v alues that resu lted from the staff's rev iew of d at a fr om th e C om an ch e P ea k te st [R ef. 1 0] a nd tw o sa fe ty e v al ua ti on r ep or ts [R ef s. 9 , 1 1].He at ing Ve nt ila ti on a nd A ir Co ndit ion ing Duc t D am pingThe dam ping v alues for he ating v entilation and air con ditioning (H VAC) sy stem s are consisten t with the g uidanc e pro v ided for bo lted stee l structu res.  B ecause no tests of w elded duct constru ction ha v e be en id en ti fi ed , th e da m pi ng v al ue s ar e th e sa m e as f or w el de d st ee l s tr uc tu re s, a nd R eg ul at or y Posi ti on 4 in Se ct ion C of thi s re vised g uid e pro vides thes e same dam pin g valuesI n addi ti on, th e NRC prov ides re lated in form ation on HVAC du ct dam ping in NU RE G/C R-6919 , "Reco m m endatio ns fo r R ev is io n of S ei sm ic D am pi ng Va lu es in R eg ul at or y G ui de 1.61" [R ef. 1 2].M e c hani c al a nd Ele c tr ic al C om pone nt Da m pingNU RE G/C R-6919 [R ef. 12] consid ers g uidanc e in Am erican Society of Civ il En g ineers (AS CE)Stand ard 4 3-05, "S eism ic D esig n C riteria for Structu res, Sy stem s, and Com pone nts in N uclear Facilities"
[Ref. 13], a nd Non-Mandatory A ppen dix N , "Dy nam ic A naly sis Metho ds," to Section I I I , D iv ision 1, of the A SME Boiler & Pressu re Vessels Cod e [R ef. 14]I n ad dition, N UR EG/CR-6919 [R ef. 12]prov ides re com m endatio ns a nd com m entary on dam ping v alues for (1) contain m ent stru ctures, contain m ent in ternal stru ctures, and othe r Se ism ic C ateg ory I structu res; (2) piping; (3) electrical distribution sy stem s (i.e., cable tray or cond uit sy stem s); (4) HVAC; and (5) m echan ical an d elec trical com pone ntsR eg ulatory Po sition 5 in Section C of this rev ised g uide prov ides th e da m ping v alues that resu lted from the staff's rev iew of this industry g uidanc e.


==B. DISCUSSION==
Rev. 1 of RG 1.61, Pa g e 4 CR EGU LAT ORY PO SITIONThe f ol lo w in g r eg ul at or y p os it io ns p ro v id e ac ce pt ab le d am pi ng v al ue s to b e us ed in th e el as ti c dy nam ic seism ic ana ly sis an d d esig n o f SS Cs, w here energ y dissip ation is app roxim ated b y v iscous dam ping unless otherw ise sp ecifiedD am ping v alues hig her th an th ose prov ided m ay be used if doc um ented te st d at a su pp or t t he h ig he r v al ue sD am pi ng v al ue s as so ci at ed w it h so il-st ru ct ur e in te ra ct io n an al y si s are n ot w ithin th e sco pe o f this reg ulatory g uide.1.
BackgroundDamping is a measure of the energy dissipation of a material or structural system as it responds todynamic excitation. It is a term used to assist in mathematically modeling and solving dynamic equationsof motion for a vibratory system in which energy is dissipated.  When performing an elastic dynamicseismic analysis, one can account for the energy dissipated by specifying the amount of viscous damping(i.e., damping force proportional to the velocity) in the analytical model.Current NRC guidance on damping values to be used in the elastic design of nuclear power plantsis presented in this regulatory guide, which was first issued in October 1973 [Ref. 2]Like the originalversion of this guide, this revision specifies equivalent viscous modal damping values as a percentageof critical damping for Seismic Category I SSCs.  However, the staff based the original damping valueson limited data, expert opinion, and other information available in 1973.  Since that time, the NRCand industry have been involved in various studies, research work, and testing to predict and estimatedamping values of SSCs.  In view of the available data, the damping values provided in the originalversion of Regulatory Guide 1.61 may not reflect realistic damping values for SSCs.  Also, it is recognizedthat additional guidance is needed to address issues, such as correlation between damping and structuresstress level, and damping values for materials not included in the original version of Regulatory Guide 1.61(e.g., electrical distribution systems and reinforced masonry structures).Over the past three decades, the nuclear industry has proposed damping values and discussedthese values during various meetings and reviews of licensing issuesNuclear industry groups and licenseeshave suggested that the NRC ought to accept more realistic damping values for seismic design and analysisof SSCs, in place of the damping values provided in the original Regulatory Guide 1.61.Structural DampingIn 1993, the NRC completed an investigation of the adequacy of original Regulatory Guide 1.61structure damping values and other recommendations, and reported the results in NUREG/CR-6011 [Ref. 3]. Data were analyzed to identify the parameters that significantly influenced structure damping.  Based onthat study, the NRC determined that the original Regulatory Guide 1.61 damping values for structure designwere adequate but required one significant revisionSpecifically, Regulatory Guide 1.61 should distinguishbetween "friction-bolted" and "bearing-bolted" connections for steel structures.  Friction-bolted connectionsare also referred to as "slip-critical" connections. In these connections, the bolt preload is high enoughto ensure that friction is not overcome, and the bolt does not experience shear loading.  RegulatoryPosition 1 in Section C of this revised guide provides the updated structural damping values.


Rev. 1 of RG 1.61, Page 3Piping DampingIn 1986, the American Society of Mechanical Engineers (ASME) established Code Case N-411,"Alternative Damping Values for Response Spectra Analysis of Class 1, 2, and 3 Piping," in Section III,Division 1, of the ASME Boiler and Pressure Vessel Code [Ref. 4]. The NRC staff used Code Case N-411,with certain limitations specified in Regulatory Guide 1.84 [Ref. 5], to review operating reactor issuesuntil Code Case N-411 expired in 2000.  The staff also approved the use of alternate damping valuesfor the General Electric Advanced Boiling Water Reactor Design in 1994 [Ref. 6], Combustion EngineeringSystem 80+ Design in 1992 [Ref. 7], and Westinghouse AP600 Design in 1998 [Ref. 8].  RegulatoryPosition 2 in Section C of this revised guide provides the piping damping values that resulted fromthe staff's experience with ASME Code Case N-411 and application reviews of new reactor designs.Electrical Distribution System DampingRegulatory Guide 1.61 did not originally provide damping values for cable tray or conduit systems. Historically, the nuclear power industry used the damping values for bolted steel structures for seismicdesign of cable tray and conduit systemsIn the late 1980s, however, the NRC staff reviewed the resultsof the cable tray test at the Comanche Peak Steam Electrical Station [Ref. 9].  Regulatory Position 3in Section C of this revised guide provides the damping values that resulted from the staff's reviewof data from the Comanche Peak test [Ref. 10] and two safety evaluation reports [Refs. 9, 11].Heating Ventilation and Air Conditioning Duct DampingThe damping values for heating ventilation and air conditioning (HVAC) systems are consistentwith the guidance provided for bolted steel structures.  Because no tests of welded duct constructionhave been identified, the damping values are the same as for welded steel structures, and RegulatoryPosition 4 in Section C of this revised guide provides these same damping values.  In addition, the NRCprovides related information on HVAC duct damping in NUREG/CR-6919, "Recommendationsfor Revision of Seismic Damping Values in Regulatory Guide 1.61" [Ref. 12].Mechanical and Electrical Component DampingNUREG/CR-6919 [Ref. 12] considers guidance in American Society of Civil Engineers (ASCE)Standard 43-05, "Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities"[Ref. 13], and Non-Mandatory Appendix N, "Dynamic Analysis Methods," to Section III, Division 1,of the ASME Boiler & Pressure Vessels Code [Ref. 14].  In addition, NUREG/CR-6919 [Ref. 12]provides recommendations and commentary on damping values for (1) containment structures,containment internal structures, and other Seismic Category I structures; (2) piping; (3) electricaldistribution systems (i.e., cable tray or conduit systems); (4) HVAC; and (5) mechanical and electricalcomponents.  Regulatory Position 5 in Section C of this revised guide provides the damping valuesthat resulted from the staff's review of this industry guidance.
St r uc tu r al D am ping 1.1 Acce ptab le Str uctu ral D amping V alues f or C onta inment Stru ctures, Con tainment Intern al S tructu res, and Other Seismic C atego ry I Str uctu res 1.1.1 Saf e-Shut down Ear thq uake (SSE)Table 1 prov ides a cceptab le dam ping v alues for the SS E a naly sis.Tab le 1.  S SE D amping V alues St ru ct ur al M at er i al D ampi ng (% of C ri t i cal D am p i ng)Rei n f or ce d Conc r et e
7%Rei n f or ce d M as on r y
7%Pre s t r es s ed Conc r et e
5%W el ded St ee l or B ol t ed St ee l w i t h Fr i ct i on Conn ec t i on s
4%B ol t ed St ee l w i t h B ea r i n g Conn ec t i on s
7%Note:
For steel structures w ith a com bin ation of diff erent conn ection ty pes, use the lowe st specif ied dam pin g v alue, or as an alternative, use a "w eighted av erag e" dam pin g v alue based on th e num ber of e ach ty pe present in th e structure.


Rev. 1 of RG 1.61, Page 4
1.1.2 Oper ati ng-Basi s Eart hquak e (OBE)I f th e de si g n-ba si s O B E g ro un d ac ce le ra ti on is s el ec te d to b e le ss th an o r eq ua l t o on e-th ir d of th e de si g n-ba si s S S E g ro un d ac ce le ra ti on , th en a s ep ar at e O B E a na ly si s is n ot r eq ui re d.  H ow ev er , if th e de si g n-ba si s O B E g ro un d ac ce le ra ti on is s el ec te d to b e g re at er th an o ne-th ir d of th e de si g n-ba si s S S E g ro un d ac ce le ra ti on , th en a s ep ar at e O B E a na ly si s sh ou ld b e co nd uc te d.  Ta bl e 2 pr ov id es a cc ep ta bl e dam ping v alues for the O BE ana ly sis.Tab le 2. OBE D amping V alues St ru ct ur al M at er i al D ampi ng (% of C ri t i cal D am p i ng)Rei n f or ce d Conc r et e
4%Rei n f or ce d M as on r y
4%Pre s t r es s ed Conc r et e
3%W el ded St ee l or B ol t ed St ee l w i t h Fr i ct i on Conn ec t i on s
3%B ol t ed St ee l w i t h B ea r i n g Conn ec t i on s
5%
Rev. 1 of RG 1.61, Pa g e 5 1.2 Spe cial C onsid eration for In-S tructu re R espo nse Spe ctra Gen erationThe SS E d am ping v alues specified in Table 1 for linear d y nam ic ana ly sis of structures hav e be en s elected based on the expec tation th at the structural respon se attribu ted to load com bination s that inc lude SSE w ill be close to ap plicable code stress lim its, a s de fined in S ection 3.8 of NU RE G-0800[R ef. 1 5].How ev er, there m ay be cases whe re the predicted structu ral resp onse to loa d co m bination s that inc lude SSE is s ig nificantly belo w the ap plicable code stress lim its.  Beca use equiv alent v iscous da m pi ng r at io s ha v e be en s ho w n to b e de pe nd en t o n th e st ru ct ur al r es po ns e le v el , it is n ec es sa ry to co nsider that the SS E d am ping v alues specified in Table 1 m ay be incons istent w ith the predicted st ru ct ur al r es po ns e le v el.For structural ev aluation, this is no t a c oncern , b ecause the stresses resulting from the use of d am ping-com patible structural respon se w ill still be less tha n the app licable c ode stress lim its, as d ef in ed in S ec ti on 3.8 of N U R E G-08 00 [R ef. 1 5].H ow ev er , f or in-st ru ct ur e re sp on se s pe ct ra g en er at io n, it is n ec es sa ry to u se th e da m pi ng-co m pa ti bl e structural respon se.  C onseq uently , th e follo wing add itional g uidanc e is prov ided for an aly ses u sed to de term ine in-structure respon se sp ectra: (1)
U se th e O B E d am pi ng v al ue s sp ec if ie d in Ta bl e 2, w hi ch a re a cc ep ta bl e to th e st af f wit hout fur the r re view.(2)
Sub m it a p lant-specific technica l basis for us e of dam ping v alues hig her th an th e O BE dam ping v alues specified in Table 2 , b ut no t g reater tha n the SS E d am ping v alues specified in Table 1 (e.g., see N UR EG/CR-6919 , S ection 3.2.3), sub j ect to staff rev iew on a cas e-by-case basis.I n g en er al , f or c er ti fi ed s ta nd ar d pl an t d es ig ns w he re th e de si g n-ba si s in-st ru ct ur e re sp on se s pe ct ra represen t the env elope of the in-structure respon ses o btained from m ultiple a naly ses co nduc ted to c on si de r a ra ng e of e xp ec te d si te s oi l c on di ti on s, it is n ot n ec es sa ry f or c om bi ne d li ce ns e ap pl ic an ts to ad dress this issu e.  H owe v er, if plan t-specific seism ic ana ly ses are con ducted for Categ ory I structu res and/or structures not in cluded as part o f the standard plan t desig n, then the ap plicant is exp ected t o a dd r e s s th i s is s ue ac c or di ngl y.


==C. REGULATORY POSITION==
Rev. 1 of RG 1.61, Pa g e 6 2.
The following regulatory positions provide acceptable damping values to be used in the elasticdynamic seismic analysis and design of SSCs, where energy dissipation is approximated by viscous dampingunless otherwise specified.  Damping values higher than those provided may be used if documentedtest data support the higher values.  Damping values associated with soil-structure interaction analysisare not within the scope of this regulatory guide.1.


Structural Damping1.1 Acceptable Structural Damping Values for Containment Structures,Containment Internal Structures, and Other Seismic Category I Structures1.1.1 Safe-Shutdown Earthquake (SSE)Table 1 provides acceptable damping values for the SSE analysis.Table 1SSE Damping ValuesStructural Material Damping (% of Critical Damping)Reinforced Concrete
P iping Da m pingTable 3 presents the constan t dam ping v alues specified for S SE and OB E (w here required)analy ses o f pipin g sy stem sThese v alues are ap plicable to tim e-history , re spon se sp ectra, and equiv alent s tatic ana ly sis pro cedure s for structural qualification
7%Reinforced Masonry
.T ab le 3D am p in g V al u es for Pip in g S ys te ms C ategory D ampi ng V al ue S S EO B E > S S E/3 Pi pi n g S y s t e ms 4%3%As an a lternativ e for respon se sp ectrum ana ly ses u sing an env elope of the SS E o r O BE respo nse spe ct ra at al l su ppor t poi nts (uni for m suppo rt m oti on), fre que ncy-dep end ent dam pin g values shown in F ig ure 1 m ay be used, sub j ect to the fo llowin g restriction s:*
7%Prestressed Concrete
Frequ ency-depen dent dam ping sho uld b e us ed c om pletely and con sistently , if at all. (Dam ping v alues specified in R eg ulatory G uide 1.6 1 are to be u sed for eq uipm ent other than piping.)*
5%Welded Steel or Bolted Steel with Friction Connections
Use of the spe cified d am ping v alues is lim ited o nly to respon se sp ectral an aly ses. Acce ptance of the use of the sp ecified dam ping v alues with other ty pes of d y nam ic ana ly ses (e.g., tim e-history ana ly ses o r inde pend ent su pport m otion m ethod) requires further j ustification.
4%Bolted Steel with Bearing Connections
 
7%Note:
*
For steel structures with a combination of different connection types, use the lowest specified damping value, or asan alternative, use a "weighted average" damping value based on the number of each type present in the structure.1.1.2 Operating-Basis Earthquake (OBE)If the design-basis OBE ground acceleration is selected to be less than or equal to one-thirdof the design-basis SSE ground acceleration, then a separate OBE analysis is not required. However,if the design-basis OBE ground acceleration is selected to be greater than one-third of the design-basisSSE ground acceleration, then a separate OBE analysis should be conductedTable 2 provides acceptabledamping values for the OBE analysis.Table 2. OBE Damping ValuesStructural Material Damping (% of Critical Damping)Reinforced Concrete
When used for reco nciliation or su pport optim iz ation of ex isting des ig ns, the effe cts of increased m otion on existing clearan ces a nd online m ounted equ ipm ent sh ould be c heck ed.*
4%Reinforced Masonry
Frequ ency-depen dent dam ping is n ot ap propriate for an aly z ing the dy nam ic resp onse of p iping s yst e ms us i ng s up po r t s de s i gne d t o d i s s i pa t e en e r gy by yi e l di ng.*
4%Prestressed Concrete
Frequ ency-depen dent dam ping is n ot ap plicable to pip ing in whic h stres s co rrosion crack ing ha s oc cu rr ed , u nl es s a ca se-sp ec if ic e v al ua ti on is p ro v id ed a nd r ev ie w ed a nd f ou nd a cc ep ta bl e by th e N R C s ta ff.
3%Welded Steel or Bolted Steel with Friction Connections
3%Bolted Steel with Bearing Connections
5%
Rev. 1 of RG 1.61, Page 51.2 Special Consideration for In-Structure Response Spectra GenerationThe SSE damping values specified in Table 1 for linear dynamic analysis of structureshave been selected based on the expectation that the structural response attributed to load combinationsthat include SSE will be close to applicable code stress limits, as defined in Section 3.8 of NUREG-0800[Ref. 15].However, there may be cases where the predicted structural response to load combinationsthat include SSE is significantly below the applicable code stress limits. Because equivalent viscousdamping ratios have been shown to be dependent on the structural response level, it is necessaryto consider that the SSE damping values specified in Table 1 may be inconsistent with the predictedstructural response level.For structural evaluation, this is not a concern, because the stresses resulting from the useof damping-compatible structural response will still be less than the applicable code stress limits,as defined in Section 3.8 of NUREG-0800 [Ref. 15].However, for in-structure response spectra generation, it is necessary to use the damping-compatiblestructural response.  Consequently, the following additional guidance is provided for analyses usedto determine in-structure response spectra:(1)
Use the OBE damping values specified in Table 2, which are acceptable to the staffwithout further review.(2)
Submit a plant-specific technical basis for use of damping values higher than the OBE dampingvalues specified in Table 2, but not greater than the SSE damping values specified in Table 1(e.g., see NUREG/CR-6919, Section 3.2.3), subject to staff review on a case-by-case basis.In general, for certified standard plant designs where the design-basis in-structure response spectrarepresent the envelope of the in-structure responses obtained from multiple analyses conductedto consider a range of expected site soil conditions, it is not necessary for combined license applicantsto address this issue.  However, if plant-specific seismic analyses are conducted for Category I structuresand/or structures not included as part of the standard plant design, then the applicant is expectedto address this issue accordingly.


Rev. 1 of RG 1.61, Page 62.
Rev. 1 of RG 1.61, Pa g e 7 3.


Piping DampingTable 3 presents the constant damping values specified for SSE and OBE (where required)analyses of piping systemsThese values are applicable to time-history, response spectra,and equivalent static analysis procedures for structural qualification.Table 3Damping Values for Piping SystemsCategoryDamping ValueSSEOBE > SSE/3Piping Systems4%3%As an alternative for response spectrum analyses using an envelope of the SSE or OBE responsespectra at all support points (uniform support motion), frequency-dependent damping values shownin Figure 1 may be used, subject to the following restrictions:*
Ele c tr ic al D ist r ibut ion Sys te m Da m pingTable 4 presents the constan t dam ping v alues specified for S SE and OB E (w here required)an al y se s of c ab le tr ay a nd c on du it s y st em sTh es e v al ue s ar e ap pl ic ab le to r es po ns e sp ec tr a and equiv alent s tatic ana ly sis pro cedure s for structural qualification.  The dam ping v alues specified in Table 4 are applicab le to all ty pes of su pports, inclu ding w elded supp orts. The us e of hig her d am ping val ue s fo r ca bl e tr a ys wi t h f l e xi bl e su pp or t sys t e ms (e.g., r od-hu ng t r a pe ze s yst e ms, st r ut-hu ng t r a pe ze sy st em s, a nd s tr ut-ty pe c an ti le v er a nd b ra ce d ca nt il ev er s up po rt s y st em s) is p er m is si bl e, s ub ject to obtainin g N RC rev iew for acc eptance on a case-by-case basis.The analy sis m ethodo log y sho uld c onside r the flexibility of supp orts in determ ining the sy stem respon se to seism ic exc itation.
Frequency-dependent damping should be used completely and consistently, if at all. (Damping values specified in Regulatory Guide 1.61 are to be used for equipmentother than piping.)*
Use of the specified damping values is limited only to response spectral analyses. Acceptance of the use of the specified damping values with other types of dynamic analyses(e.g., time-history analyses or independent support motion method) requires further justification.*
When used for reconciliation or support optimization of existing designs, the effects of increasedmotion on existing clearances and online mounted equipment should be checked.*
Frequency-dependent damping is not appropriate for analyzing the dynamic response of pipingsystems using supports designed to dissipate energy by yielding.*
Frequency-dependent damping is not applicable to piping in which stress corrosion crackinghas occurred, unless a case-specific evaluation is provided and reviewed and found acceptableby the NRC staff.


Rev. 1 of RG 1.61, Page 73.
Rev. 1 of RG 1.61, Pa g e 8 T ab le 4.  D am p in g V al u es for E le ct ri ca l D is tr ib u ti on S ys te ms C ategory D ampi ng V al ue S S EO B E > S S E/3 C abl e Tray Syst em 4 M axi m um C ab l e Lo ad i ng 1 E m p ty 2 Spray ed-on Fi r e Ret ar dant or ot her ca b l e-restraini ng m ec ha nism 3 10%7%7%7%5%5%C on du i t S ys t e ms 4 M a x im u m C a b le fi ll 1 E m p ty 2 7%5%5%3%Notes: 1.


Electrical Distribution System DampingTable 4 presents the constant damping values specified for SSE and OBE (where required)analyses of cable tray and conduit systems.  These values are applicable to response spectraand equivalent static analysis procedures for structural qualification.  The damping values specifiedin Table 4 are applicable to all types of supports, including welded supports.  The use of higher dampingvalues for cable trays with flexible support systems (e.g., rod-hung trapeze systems, strut-hung trapezesystems, and strut-type cantilever and braced cantilever support systems) is permissible, subject toobtaining NRC review for acceptance on a case-by-case basis.The analysis methodology should consider the flexibility of supports in determining the systemresponse to seismic excitation.
Maxim um ca ble load ings, in accordance w ith th e plant design specif ication , are to be utilized in con jun ction w ith th ese dam pin g v alues.2.


Rev. 1 of RG 1.61, Page 8Table 4Damping Values for Electrical Distribution SystemsCategoryDamping ValueSSEOBE > SSE/3Cable Tray System4Maximum Cable Loading1Empty2Sprayed-on Fire Retardant or othercable-restraining mechanism310%7%7%7%5%5%Conduit Systems4Maximum Cable fill1Empty27%5%5%3%Notes:1.
Spa re c abl e tra y a nd c onduit, ini tia lly e m pty , m ay be a nal y ze d w ith ze ro c abl e loa d a nd the se da m ping v al ues(Not e:  R e-ana ly si s is e x pec te d w hen put i nto s er v ic e.)3.


Maximum cable loadings, in accordance with the plant design specification, are to be utilizedin conjunction with these damping values.2.
Res tr ai n t o f th e free re la ti ve m o vement of th e cab le s in si d e a tr ay red u ces t h e system dampi n g.4.


Spare cable tray and conduit, initially empty, may be analyzed with zero cable load and these dampingvalues.  (Note:  Re-analysis is expected when put into service.)3.
W hen ca ble loa ding s of le ss-tha n m ax im um a re s pec if ie d f or de si g n c al cul at ions , t he appl ic ant or licensee is e xpected to justify the selec ted dam pin g v alues and ob tain NRC rev iew f or acce ptan ce on a c ase-by-case basis.4.


Restraint of the free relative movement of the cables inside a tray reduces the system damping.4.
He at ing , V e nt ila ti on, and A ir Co ndit ion ing Duc t D am pingTable 5 presents the constan t dam ping v alues specified for S SE and OB E (w hen required)analy ses o f H VAC duct sy stem s.  These v alues are ap plicable to resp onse spectra and equiv alent static an aly sis pro cedure s for structural qualification
.The analy sis m ethodo log y m ust co nsider the flex ibility of supp orts in determ ining sy stem respon se to seism ic exc itation.T ab le 5.  D am p in g V al u es for HV A C D u ct S ys te ms Type of D uc t C ons t ru ct i on D ampi ng V al ue S S EO B E > S S E/3 Pock et Loc k10%7%Compan i on An g l e7%5%W el ded4%3%
Rev. 1 of RG 1.61, Pa g e 9 5.


When cable loadings of less-than maximum are specified for design calculations, the applicantor licensee is expected to justify the selected damping values and obtain NRC review for acceptanceon a case-by-case basis.4.
M e c hani c al a nd Ele c tr ic al C om pone nt Da m pingTab le 6 p re se nt s th e da m pi ng v al ue s fo r m ec ha ni ca l a nd e le ct ri ca l c om po ne nt s, w hi ch a re ap pl ic ab le to p as si v e su bc om po ne nt s th at c an b e se is m ic al ly q ua li fi ed b y a na ly si s.  A ct iv e su bc om po ne nt s do n ot r ea di ly le nd th em se lv es to s ei sm ic q ua li fi ca ti on b y a na ly si s, a nd r eq ui re q ua li fi ca ti on b y te st , as d es cr ib ed in S ec ti on 3.10 o f N U R E G-08 00 [R ef. 1 5].T ab le 6.  D am p in g V al u es for Me ch an ic al a n d E le ct ri ca l C om p on en ts C ompone nt Type D ampi ng V al ue S S EO B E > S S E/3 M o t o r, Fan, and C
o m p res sor H o usi ngs (p ro te c tio n , stru c tur a l sup p o rt)3%2%P ressu re V esse l s, H ea t E xc ha ng ers, an d P um p an d V alve B o d i es (p re ssu re b o u n d a ry)3%2%W el d ed Ins t rume nt R acks (s tru c tur a l sup p o rt)3%2%El ec t r i ca l Cabi n et s , Pan el s , a n d M ot or C o ntro l C en t ers (M C C s)(p ro te c tio n , stru c tur a l sup p o rt)3%2%M et al A t m o spheri c Storage T
anks (contai nm ent , pro t ect i o n) - I mpu l s i v e M ode - Sl os h i n g M ode 3%0.5%2%0.5%
Rev. 1 of RG 1.61, Pa g e 10 D.  IMP LEM ENT ATIONThe purp ose of this section is to prov ide in form ation to ap plicants and licensees reg arding th e N R C s ta ff's p la ns f or u si ng th is r eg ul at or y g ui de.  N o ba ck fi tt in g is in te nd ed o r ap pr ov ed in conn ection with the issu ance of this g uide.Exce pt in those cases in w hich an a pplican t or licensee propo ses o r has prev iously estab lished an a cceptab le alterna tiv e m ethod for co m ply ing w ith sp ecified portion s of the N RC's reg ulations, th e N R C s ta ff w il l u se th e m et ho ds d es cr ib ed in th is g ui de to e v al ua te (1) s ub m it ta ls in c on ne ct io n w it h applicatio ns fo r con struction perm its, sta ndard plan t desig n ce rtifications, op erating licens es, early site perm its, a nd com bined licenses;
and (2) su bm ittals from op erating reacto r license es who v oluntarily pro pose to initiate sy stem m odification s if th ere is a clear nexu s be tween the propo sed m odification s an d the sub j ect for whic h g uidanc e is prov ided herein.R EG U LA TO R Y A N A LY SI S / B A C KF IT A N A LY SI SThe r eg ul at or y a na ly si s an d ba ck fi t a na ly si s fo r th is r eg ul at or y g ui de a re a v ai la bl e in Draft Reg ulatory G uide DG-1157 , "Dam ping Values for S eism ic D esig n o f N uclear Pow er P lants"(R ef. 1 6).  Th e N R C is su ed D G-11 57 in O ct ob er 2 00 6 to s ol ic it p ub li c co m m en t o n th e dr af t o f th is Rev ision 1 o f R eg ulatory G uide 1.6 1.


Heating, Ventilation, and Air Conditioning Duct DampingTable 5 presents the constant damping values specified for SSE and OBE (when required)analyses of HVAC duct systemsThese values are applicable to response spectra and equivalentstatic analysis procedures for structural qualification.The analysis methodology must consider the flexibility of supports in determining systemresponse to seismic excitation.Table 5Damping Values for HVAC Duct SystemsType of Duct ConstructionDamping ValueSSEOBE > SSE/3Pocket Lock10%7%Companion Angle7%5%Welded4%3%
A ll NR C r eg ula tions li st ed her ei n a re a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on t he NR C's 3 public W eb si te , a t http://w w w.nrc.g ov/re adi ng-r m/doc-c olle ct ions/c f r/pa rt050.  C opie s ar e al so av ai la ble f or i nspe ct ion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room a t 11555 Roc k v ill e Pike , R ock v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555; te le phone (301) 415-4737 or (800) 397-4209; f ax (301)415-3548;
Rev. 1 of RG 1.61, Page 95.
em ai l PDR@nrc.g ov.A ll re g ula tory g uide s lis te d he re in w er e publis hed by the U.S. Nuc le ar Re g ula tory Com m is si on or its pre dec es sor , 4 the U.S. A tom ic Ene rg y Com m is si onM ost a re a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on the N RC's publi c W eb si te , a t http://ww w.nrc.gov/readin g-rm/do c-collection s/reg-g uid es/. S ing le c opie s of re g ula tory g uide s m ay a ls o be obta ine d f re e of c har g e by w rit ing the Re produc tion and Di st ribut ion Se rv ic es Se ct ion, A DM, U SN RC , W as hing ton, DC 20555-0001, by f ax to (301) 415-2289, or by e m ai l t o DI ST RI BU T IO N@nrc.g ov. A ct iv e g uide s m ay a ls o be purc has ed f rom the N at iona l T ec hnic al Inf orm at ion Se rv ic e (N T IS)D et ai ls m ay be obta ine d by c onta ct ing N T IS at 5285 Port R
oy al Roa d, Spr ing f ie ld, Virg inia 22161, onl ine a t http://w w w.nti s.g ov , by te le phone at (800) 553-N T IS (6847) or (703) 605-6000, or by f ax to (703) 605-6900.


Mechanical and Electrical Component DampingTable 6 presents the damping values for mechanical and electrical components, which areapplicable to passive subcomponents that can be seismically qualified by analysisActive subcomponentsdo not readily lend themselves to seismic qualification by analysis, and require qualification by test,as described in Section 3.10 of NUREG-0800 [Ref. 15].Table 6Damping Values for Mechanical and Electrical ComponentsComponent TypeDamping ValueSSEOBE > SSE/3Motor, Fan, and Compressor Housings(protection, structural support)3%2%Pressure Vessels, Heat Exchangers,and Pump and Valve Bodies (pressure boundary)3%2%Welded Instrument Racks(structural support)3%2%Electrical Cabinets, Panels, and MotorControl Centers (MCCs)(protection, structural support)3%2%Metal Atmospheric Storage Tanks(containment, protection) - Impulsive Mode - Sloshing Mode3%0.5%2%0.5%
C opie s ar e al so av ai la ble f or ins pec tion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room (PDR), w hic h is loc at ed at 11555 R ock v ill e P ike, Rock ville, Mary land; the P DR's m ailing address is USNRC
Rev. 1 of RG 1.61, Page 10
P DR, W ashington , DC 205 55-00 01T he P DR ca n a ls o be re ac hed by te le phone at (301) 415-4737 or (800) 397-4209, by f ax a t (301) 415-3548, a nd by e m ai l to PDR@nrc.g ov.A ll NU RE G-s er ie s re ports li st ed her ei n w er e publis hed by the U.S. Nuc le ar Re g ula tory Com m is si onC opie s ar e 5 ava ilable f or in spection or copying f or a f ee f rom the NRC's Pu blic Docume nt Ro om at 115 55 Rockv ille P ike, Roc k v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555; te le phone (301) 415-4737 or (800) 397-4209; f ax (301) 415-3548;
e m ai l PDR@nrc.g ov.  C opie s ar e al so av ai la ble a t c urr ent ra te s f rom the U.S. G ov er nm ent Printi ng O f f ic e, P.O. Box 37082, W as hing ton, DC 20402-9328, te le phone (202) 512-1800;
or f rom the N at iona l T ec hnic al Inf orm at ion Se rv ic e (N T IS) a t 5285 Port Roy al Roa d, Spr ing f ie ld, Virg inia 22161, online a t http://w w w.nti s.g ov, by te le phone at (800) 553-N T IS (6847) or (703) 605-6000, or by f ax to (703) 605-6900.


==D. IMPLEMENTATION==
NU RE G-0800 a nd N UR EG/C R-6919 a re a ls o a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on the N RC's publi c W eb si te , a t http://ww w.nrc.gov/ reading-rm
The purpose of this section is to provide information to applicants and licensees regardingthe NRC staff's plans for using this regulatory guide.  No backfitting is intended or approved inconnection with the issuance of this guide.Except in those cases in which an applicant or licensee proposes or has previously establishedan acceptable alternative method for complying with specified portions of the NRC's regulations,the NRC staff will use the methods described in this guide to evaluate (1) submittals in connection withapplications for construction permits, standard plant design certifications, operating licenses,early site permits, and combined licenses; and (2) submittals from operating reactor licenseeswho voluntarily propose to initiate system modifications if there is a clear nexus between the proposedmodifications and the subject for which guidance is provided herein.REGULATORY ANALYSIS / BACKFIT ANALYSISThe regulatory analysis and backfit analysis for this regulatory guide are available inDraft Regulatory Guide DG-1157, "Damping Values for Seismic Design of Nuclear Power Plants"(Ref. 16).  The NRC issued DG-1157 in October 2006 to solicit public comment on the draft of thisRevision 1 of Regulatory Guide 1.61.
/do c-collection s/nu regs/.Cop ies m ay be obt ained from the A m erican Society of Mechanical Engineers, T
hree P ark A venue, New York, NY 6 10016-5990.


All NRC regulations listed herein are available electronically through the Electronic Reading Room on the NRC's3public Web site, at http://www.nrc.gov/reading-rm/doc-collections/cfr/part050.  Copies are also available for inspectionor copying for a fee from the NRC's Public Document Room at 11555 Rockville Pike, Rockville, MD; the PDR'smailing address is USNRC PDR, Washington, DC 20555; telephone (301) 415-4737 or (800) 397-4209; fax (301)415-3548; email PDR@nrc.gov.All regulatory guides listed herein were published by the U.S. Nuclear Regulatory Commission or its predecessor,4the U.S. Atomic Energy Commission.  Most are available electronically through the Electronic Reading Roomon the NRC's public Web site, at http://www.nrc.gov/reading-rm/doc-collections/reg-guides/.  Single copies ofregulatory guides may also be obtained free of charge by writing the Reproduction and Distribution Services Section,ADM, USNRC, Washington, DC 20555-0001, by fax to (301) 415-2289, or by email to DISTRIBUTION@nrc.gov. Active guides may also be purchased from the National Technical Information Service (NTIS).  Details may beobtained by contacting NTIS at 5285 Port Royal Road, Springfield, Virginia 22161, online at http://www.ntis.gov,by telephone at (800) 553-NTIS (6847) or (703) 605-6000, or by fax to (703) 605-6900.  Copies are also available forinspection or copying for a fee from the NRC's Public Document Room (PDR), which is located at 11555 RockvillePike, Rockville, Maryland; the PDR's mailing address is USNRC PDR, Washington, DC 20555-0001.  The PDRcan also be reached by telephone at (301) 415-4737 or (800) 397-4209, by fax at (301) 415-3548, and by emailto PDR@nrc.gov.All NUREG-series reports listed herein were published by the U.S. Nuclear Regulatory Commission.  Copies are5available for inspection or copying for a fee from the NRC's Public Document Room at 11555 Rockville Pike,Rockville, MD; the PDR's mailing address is USNRC PDR, Washington, DC 20555; telephone (301) 415-4737or (800) 397-4209; fax (301) 415-3548; email PDR@nrc.gov.  Copies are also available at current rates fromthe U.S. Government Printing Office, P.O. Box 37082, Washington, DC 20402-9328, telephone (202) 512-1800;or from the National Technical Information Service (NTIS) at 5285 Port Royal Road, Springfield, Virginia 22161,online at http://www.ntis.gov, by telephone at (800) 553-NTIS (6847) or (703) 605-6000, or by fax to (703) 605-6900. NUREG-0800 and NUREG/CR-6919 are also available electronically through the Electronic Reading Roomon the NRC's public Web site, at http://www.nrc.gov/ reading-rm/doc-collections/nuregs/.Copies may be obtained from the American Society of Mechanical Engineers, Three Park Avenue, New York, NY610016-5990.  Phone (212)591-8500; fax (212)591-8501; www.asme.org.Rev. 1 of RG 1.61, Page 11REFERENCES1.
Phone (212)591-8500; f ax (212)591-8501;  
w w w.a sm e.org.Rev. 1 of RG 1.61, Pa g e 11 REF ERE NC ES 1.


U.S. Code of Federal Regulations, Title 10, Part 50, "Domestic Licensing of Productionand Utilization Facilities," U.S. Nuclear Regulatory Commission, Washington, DC.32.
U.S. Cod e of Fede ral R egulatio ns , Title 10 , P art 50 , "Dom estic L icensing of Prod uction and Util izat ion Faci li ti es," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.3 2.


Regulatory Guide 1.61, "Damping Values for Seismic Design of Nuclear Power Plants,"U.S. Atomic Energy Commission, Washington, DC, October 1973.43.
Reg ulatory G uide 1.6 1, "Dam ping Values for S eism ic D esig n o f N uclear Pow er P lants,"U.S. Atom ic E nerg y C om m ission, Washin g ton, DC , O ctober 1973.4 3.


NUREG/CR-6011, "Review of Structure Damping Values for Elastic Seismic Analysis ofNuclear Power Plants," U.S. Nuclear Regulatory Commission, Washington, DC, March 1993.54.
NU RE G/C R-6011 , "Rev iew of S tructure Dam ping Values for E lastic S eism ic A naly sis of Nuc lear P owe r Plan ts," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , March 19 93.5 4.


"ASME Boiler and Pressure Vessel Code, Code Case N-411-1, Alternative Damping Valuesfor Response Spectra Analysis of Class 1, 2 and 3 Piping," Section III, Division 1,American Society of Mechanical Engineers, New York, New York, February 20, 1986.65.
"AS ME B oiler an d P ressure Vessel C ode, C ode Case N-411-1, Alterna tiv e D am ping Values for R espon se S pectra Ana ly sis of Class 1, 2 an d 3 Pip ing ," Section I I I , D iv ision 1, Am erican Society of Mechanica l En g ineers, N ew York , N ew York , F ebruary 20 , 1 986.6 5.


Regulatory Guide 1.84, "Design, Fabrication, and Materials Code Case Acceptability -ASME Section III," U.S. Nuclear Regulatory Commission, Washington, DC.36.
Re gul a t or y Gui de 1.84 , "De s i gn, Fa br i c a t i on , a nd Ma t e r i a l s Co de Ca s e Ac c e pt a bi l i t y -ASME Se ct ion I I I ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.3 6.


NUREG-1503, "Final Safety Evaluation Report Related to the Certification of the AdvancedBoiling-Water Reactor," U.S. Nuclear Regulatory Commission, Washington, DC, July 1994.4 Copies are available for inspection or copying for a fee from the NRC's Public Document Room at 11555 Rockville Pike,7Rockville, MD; the PDR's mailing address is USNRC PDR, Washington, DC 20555 (telephone:  301-415-4737or 800-397-4209; fax:  301-415-3548; email:  PDR@nrc.gov).Copies may be purchased from the American Society for Civil Engineers (ASCE), 1801 Alexander Bell Drive,8Reston, VA 20190 [phone: (800) 548-ASCE (2723)].  Purchase information is available through the ASCE Web siteat http://www.pubs.asce.org.Draft Regulatory Guide DG-1157 is available electronically under Accession #ML062680189 in the NRC's9Agencywide Documents Access and Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html. Copies are also available for inspection or copying for a fee from the NRC's Public Document Room (PDR), which islocated at 11555 Rockville Pike, Rockville Maryland; the PDR's mailing address is USNRC PDR, Washington, DC20555-0001.  The PDR can also be reached by telephone at (301) 415-4737 or (800) 397-4209 by faxat (301) 415-3548, and by email to PDR@nrc.gov.Rev. 1 of RG 1.61, Page 127.
NU RE G-1503 , "Final Safety Ev aluation Rep ort R elated to the C ertification of the A dv anced Boilin g-Water R eactor," U.S. N uclear Reg ulatory C om m ission, Washin g ton, DC , July 19 94.4 Cop ies a re av ailable f or in spection or copying f or a f ee f rom the NRC's Pu blic Docume nt Ro om at 115 55 Rockv ille P ike, 7 Roc k v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555 (te le phone:  301-415-4737 or 800-397-4209;  
f ax:  301-415-3548; e m ai l:  PDR@nrc.g ov).Cop ies m ay be purch ased f rom the A m erican Society f or Civil Engineers (A
SCE), 1 80 1 A lexa nd er Be ll Drive, 8 Re st on, VA 20190 [phone: (800) 548-A SCE (2723)].  Purcha se inf orm at ion i s av ai la ble thr oug h the A SCE W eb si te at http://w w w.pubs.a sc e.org.Dr af t R eg ula tory G uide D G-1157 i s av ai la ble e le ct ronic al ly unde r A cc es si on #ML 062680189 in the N RC's 9 A g enc y w ide D ocum ent s A cc es s and Ma nag em ent Sy st em (A DA MS) a t ht tp://w w w.nrc.g ov/re adi ng-r m/a dam s.htm l. Copi es a re a ls o a v ai la ble f or i nspe ct ion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room (PDR), w hic h is located at 115
55 Rockv ille P ike, Rock ville Mary land; the P DR's m ailing address is USNRC  
P DR, W ashington , DC 20 55 5-0 00 1.  The PDR can also be reac hed b y telepho ne at (301) 415-47 37 or (80 0) 39 7-4 20 9 by f ax at (301) 415-3548, a nd by e m ai l t o PDR@nrc.g ov.Rev. 1 of RG 1.61, Pa g e 12 7.


NUREG-1462, "Draft Safety Evaluation Report related to the Design Certification of the System 80+Design," U.S. Nuclear Regulatory Commission, Washington, DC, September 1992.48.
NU RE G-1462 , "Draft Safety Ev aluation Rep ort related to the D esig n C ertification of the Sy stem 80+Desig n," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , S eptem ber 1 992.4 8.


NUREG-1512, "Final Safety Evaluation Report related to Certification of the AP600 StandardDesign," U.S. Nuclear Regulatory Commission, Washington, DC, September 1998.49.
N U R E G-15 12 , "F in al S af et y E v al ua ti on R ep or t r el at ed to C er ti fi ca ti on o f th e A P 60 0 S ta nd ar d Desig n," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , S eptem ber 1 998.4 9.


NUREG-0797, "Safety Evaluation Report Related to the Operation of Comanche Peak SteamElectric Station, Units 1 and 2," Supplement No. 16, U.S. Nuclear Regulatory Commission,Washington, DC, July 1988.410.
NU RE G-0797 , "Safety Ev aluation Rep ort R elated to the O peration of Com anche Pe ak Stea m Electric Station, U nits 1 and 2," S upplem ent N o. 16, U.S. N uclear Reg ulatory C om m ission, Washing ton, DC , July 19 88.4 10.


Ware, A.G., and C.B. Slaughterbeck, "A Survey of Cable Tray and Conduit Damping Research,"Idaho National Engineering Laboratory, Report No. EGG-EA-7346, Rev. 1, prepared forthe U.S. Nuclear Regulatory Commission, Washington, DC, August 1986.711.
Ware, A.G., a nd C.B. Slau g hterbeck , "A Surv ey of Cab le Tray and C ondu it Da m ping R esearch,"I daho N ational Eng ineering La boratory , R eport No. EG G-EA-7346 , R ev. 1 , p repared for the U.S. N uclear Reg ulatory C om m ission, Washin g ton, DC , A ug ust 1 986.7 11.


NUREG-0847, "Safety Evaluation Report for Watts Bar Nuclear Plant, Units 1 and 2,"Supplement No. 8, U.S. Nuclear Regulatory Commission, Washington, DC, January 1992.412.
NU RE G-0847 , "Safety Ev aluation Rep ort for Watts B ar N uclear Plant, U nits 1 and 2,"Sup plem ent N o. 8, U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , January 19 92.4 12.


NUREG/CR-6919, "Recommendations for Revision of Seismic Damping Values for the SeismicDamping Values in Regulatory Guide 1.61," U.S. Nuclear Regulatory Commission, Washington,DC, November 2006.413.
N U R E G/C R-69 19 , "R ec om m en da ti on s fo r R ev is io n of S ei sm ic D am pi ng Va lu es f or th e S ei sm ic Dam ping Values in R eg ulatory G uide 1.6 1," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , N ov em ber 2 006.4 13.


American Society of Civil Engineers, ASCE Standard 43-05, "Seismic Design Criteriafor Structures, Systems, and Components in Nuclear Facilities," Reston, VA, 2005.814.
A m er ic an S oc ie ty o f C iv il E ng in ee rs , A S C E S ta nd ar d 43-05 , "S ei sm ic D es ig n C ri te ri a for S tructures, Sy stem s, and Com pone nts in N uclear Facilities," R eston, VA, 20 05.8 1 4.


American Society of Mechanical Engineers, "Boiler and Pressure Vessel Code," Section III,Division 1, Non-Mandatory Appendix N, "Dynamic Analysis Methods," New York, New York,2004.515.
A me r i c a n So c i e t y o f M e c h a n i c a l En gi n e e r s , "B o i l e r a n d Pr e s s u r e V e s s e l Co d e ," Se c t i o n I II , Di vis i on 1, Non-M a nd a t or y App e nd i x N, "D yna mic Ana l ysi s Me t ho ds ," Ne w Yo r k, Ne w Yo r k, 2004.5 15.


NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for NuclearPower Plants," U.S. Nuclear Regulatory Commission, Washington, DC.416.
NU RE G-0800 , "Stand ard R ev iew Plan for the R ev iew of S afety A naly sis R eports for N uclear Power Plan ts ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.4 16.


Draft Regulatory Guide DG-1157, "Damping Values for Seismic Design of Nuclear PowerPlants," U.S. Nuclear Regulatory Commission, Washington, DC.9  
Draft Reg ulatory G uide DG-1157 , "Dam ping Values for S eism ic D esig n o f N uclear Pow er Pla nts ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.9}}
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Revision as of 07:21, 31 August 2018

Damping Values for Seismic Design of Nuclear Power Plants
ML070260029
Person / Time
Issue date: 03/12/2007
From:
NRC/RES/DFERR/DDERA/MSEB
To:
Graves HL (301)415-5880
Shared Package
ML070260020 List:
References
DG-1157 RG-1.061, Rev. 1
Download: ML070260029 (12)


Stru ctures, sy stem s, and com po nent s of a nuclear pow er plant th at are designated as Seism ic Cate gory I are designed 1 to w iths ta nd the e f f ec ts of the s af e shut dow n e ar thqua k e (SS E) and re m ai n f unct iona l, se e Re g ula tory G uide 1.29,"S ei sm ic D es ig n Cl as si f ic at ion."A ppendi x S t o 10 C FR Part 50 a pplie s to a pplic ant s f or a de si g n c er tif ic at ion or c om bine d li ce nse purs uant to 2 10 CF R Par t 52, "Ea rly Sit e Perm its; St anda rd D es ig n Ce rti f ic at ions; a nd Com bine d L ic ens es f or N ucl ea r Pow er Plant s,"or a constru ction perm it or op erating license pu rsuant to 10 CFR P art 50 af ter Ja nu ary 10, 199 7. Howe ver, f or either an op era ti n g li cen se ap p li can t o r h o ld er who se co n st ru ct io n pe rmit w as i ssu ed be for e Jan u ary 10 , 1 9 9 7 , t h e ear th q u ake e n g i n e e r i n g c r i t e r i a i n S e c t i o n V I o f Ap p e n d i x A t o 1 0 C F R P a r t 1 0 0 c o n t i n u e t o a p p l y.T h e U.S. N u c le a r R e g u la to ry C o m m is s io n (N R C) i s s u e s re g u la to ry g u id e s to d e s c rib e a n d m a k e a v a il a b le to th e p u b li c m e th o d s th a t t h e N R C s ta ff con si der s acc ept abl e f or us e i n i m pl em ent i ng spe ci f i c par t s of t he age ncy's r egu l at i ons , t ech ni que s t hat t he st af f us es i n e val uat i ng spe ci f i c pr obl em s or po st ul at ed acc i den t s, an d d at a t hat t he st af f ne ed i n r evi ewi ng app l i cat i ons f or pe r m i t s and l i cen ses. Regul at or y gu i des ar e n ot s ubs t i t ut es f or r egu l at i ons , an d c om pl i anc e wi t h t hem i s not r equ i r ed. Met hod s and s ol ut i ons t hat di f f er f r om t hos e s et f or t h i n r egu l at or y gu i des wi l l be de em ed acc ept abl e i f t hey pr ovi de a b asi s f or t he f i ndi ngs r equ i r ed f or t he i ss uan ce or c ont i nua nce of a per m i t or l i cen se by t he C om m i ss i on.T hi s gui de was i ss ued af t er c ons i der at i on of c om m ent s r ece i ved f r om t he pub l i c. The N R C s t af f en cou r age s and wel com es com m ent s and s ugg est i ons in c o n n e c ti o n w it h i m p ro v e m e n ts to p u b li s h e d re g u la to ry g u id e s , a s w e ll a s i te m s fo r i n c lu s io n i n re g u la to ry g u id e s th a t a re c u rre n tl y b e in g d e v e lo p e d. T h e N R C s ta ff w il l re v is e e xis ti n g g u id e s , a s a p p ro p ria te , t o a c c o m m o d a te c o m m e n ts a n d to re fl e c t n e w i n fo rm a ti o n o r e xp e rie n c e. W rit te n c o m m e n ts m ay be s ubm i t t ed t o t he R ul es and D i r ect i ves Br anc h, O f f i ce of Adm i ni st r at i on, U.S. N ucl ear R egu l at or y C om m i ss i on, W ash i ngt on, D C 20 555-000 1.R egul at or y gui des ar e i ssued i n 10 br oad di vi si ons: 1, P ow er R eact or s; 2, R esear ch and T est R eact or s; 3, Fuel s and M at er i al s Faci l i t i es;4, Env i r on m en t al a nd Si t i ng; 5 , Ma t er i al s a nd Pl an t Pr ot ec t i on; 6 , Pr od uc t s; 7 , Tr an s po r t at i on; 8 , Occ up at i on al Hea l t h; 9 , Ant i t r us t a nd F i na nc i al Rev i ew;a n d 1 0 , G e n e ra l.R equ est s f or s i ngl e c opi es of dr af t or ac t i ve r egu l at or y gu i des (whi ch m ay be r epr odu ced) s hou l d b e m ade t o t he U.S. N ucl ear R egu l at or y C om m i ss i on, W ash i ngt on, D C 20 555 , At t ent i on: R epr odu ct i on and D i st r i but i on S er vi ces Sect i on, or by f ax t o (301) 41 5-228 9; or by em ai l t o D i st r i but i on@nr c.gov. E l ect r oni c cop i es of t hi s gui de and ot her r ece nt l y i ss ued gu i des ar e a vai l abl e t hr oug h t he N R C's pub l i c W eb si t e u nde r t he R egu l at or y G ui des do cum ent c o ll e c ti o n o f t h e N R C's E le c tro n ic R e a d in g R o o m a t ht t p://w w w.nr c.gov/r eadi ng-r m/doc-col l ect i ons/ a n d th ro u g h th e N R C's A g e n c yw id e D o c u m e n ts A c c e s s a n d M a n a g e m e n t S ys te m (A D A M S) a t h ttp://w w w.n rc.g o v/re a d in g-rm/a d a m s.h tm l, un der Acces si on N o. ML0702 600 29.U.S. N UC LEA R RE GU LA TO RY C OM MI SSIO N

M ar ch 2007 R ev i si on 1 RE GUL AT ORY GUI DE OFFICE OF NUCL

EA R REGULA TORY RESEA RCH R E G U LA TO R Y G U I D E 1.61 (D r af t w as i ssued as DG-1157, dat ed O ct ober 200 6)DA MPI NG VA L UE S F OR SE I SMI C D ES I GN O F N U C LE A R P O W E R P LA N TS A. INT ROD UC TIONThis reg ulatory g uide is bein g rev ised to up date th e g uidanc e for applican ts and licens ees reg arding the acceptab le dam ping v alues that the U.S. N uclear Reg ulatory C om m ission (NR C) staff use d in the seism ic resp onse analy sis of Seism ic C ateg ory I nu clear p owe r plan t structu res, sy stem s, 1 and com pone nts (S SC s) in accord ance with Title 10, Part 5 0, of the Cod e of Fede ral R egulatio ns (1 0 C F R P ar t 5 0), "D om es ti c L ic en si ng o f P ro du ct io n an d U ti li z at io n F ac il it ie s" [R ef. 1].Spec ifically , G eneral Desig n C riterion 2 , "Desig n B ases fo r Pro tection Ag ainst N atural P heno m ena,"of A ppen dix A , "Gen eral D esig n C riteria for Nuc lear P owe r Plan ts," to 10 C FR Pa rt 50 requires that SSC s im portant to safe ty be desig ned to w ithstand the effe cts of natural phen om ena such as ea rthquak es witho ut los ing the ability to perform their safety fun ctions. S uch SSC s m ust also be desig ned to a cc om m od at e th e ef fe ct s of a nd b e co m pa ti bl e w it h th e en v ir on m en ta l c on di ti on s as so ci at ed w it h norm al op eration and postula ted ac cidents. A ppen dix S , "Earthq uak e E ng ineering C riteria for Nuc lear Po we r Pl a nt s ," to 10 CFR Pa r t 50 sp e c i f i e s th e re qu i r e men t s fo r th e impl e men t a t i on of Ge ne r a l De s i gn Criterion 2 with respect to earth quak es.2 Rev. 1 of RG 1.61, Pa g e 2Thi s re g ul at or y g ui de s pe ci fi es th e da m pi ng v al ue s th at th e N R C s ta ff c on si de rs a cc ep ta bl e for co m ply ing w ith the ag ency's reg ulations and g uidanc e for seism ic ana ly sis. The sp ecified dam ping v alues are inte nded for elastic m odal dy nam ic seism ic ana ly sis w here energ y dissip ation is acco unted for by v is co us d am pi ng (i.e., th e da m pi ng f or ce is p ro po rt io na l t o th e v el oc it y).Thi s re g ul at or y g ui de c on ta in s in fo rm at io n co ll ec ti on s th at a re c ov er ed b y th e re qu ir em en ts of 1 0 C FR Pa rt 50, w hich the O ffice of Manag em ent an d B udg et (O MB) a pprov ed u nder OMB con trol num ber 3 150-0011. The NR C m ay neith er co nduc t nor spon sor, and a pe rson is no t requ ired to respo nd to, an in fo rm at io n co ll ec ti on r eq ue st o r re qu ir em en t u nl es s th e re qu es ti ng d oc um en t d is pl ay s a cu rr en tl y v al id O MB c on tr ol n um be r.B. DISC US SION Bac kgr oundD am pi ng is a m ea su re o f th e en er g y d is si pa ti on o f a m at er ia l o r st ru ct ur al s y st em a s it r es po nd s to dy nam ic exc itation. I t is a term use d to assist in m athem atically m odeling and solv ing dy nam ic equ ations of m ot io n fo r a v ib ra to ry s y st em in w hi ch e ne rg y is d is si pa te d. W he n pe rf or m in g a n el as ti c dy na m ic seism ic ana ly sis, one can accou nt for the en erg y dissip ated b y spe cify ing the am ount of v iscous dam ping (i.e., d am pi ng f or ce p ro po rt io na l t o th e v el oc it y) in th e an al y ti ca l m od el.C ur re nt N R C g ui da nc e on d am pi ng v al ue s to b e us ed in th e el as ti c de si g n of n uc le ar p ow er p la nt s is pres ented in this reg ulatory g uide, w hich was first issued in Octo ber 1 973 [Ref. 2]. L ik e the orig inal ver s i on of th i s gui de , t hi s re vis i on sp e c i f i e s eq ui val e nt vis c ou s m od a l da mpi ng val ue s as a p e r c e nt a ge of critical dam ping for Seism ic C ateg ory I SS Cs. H owe v er, the sta ff base d the orig inal d am ping v alues on li m it ed da ta , expe rt opin ion , and ot her inf ormati on avail abl e in 19 73. Sinc e tha t ti m e, th e NRC an d in du st ry h av e be en in v ol v ed in v ar io us s tu di es , r es ea rc h w or k , a nd te st in g to p re di ct a nd e st im at e dam ping v alues of S SC s. I n v iew of the av ailable d ata, the d am ping v alues prov ided in the orig inal v ersion of R eg ulatory G uide 1.6 1 m ay no t reflect realistic da m ping v alues for S SC s. A lso, it is rec og niz ed that ad ditional g uidanc e is neede d to address issue s, such as co rrelation betw een dam ping and structu res stress lev el, a nd dam ping v alues for m aterials n ot inc luded in the orig inal v ersion of R eg ulatory G uide 1.6 1 (e.g., e le ct ri ca l d is tr ib ut io n sy st em s an d re in fo rc ed m as on ry s tr uc tu re s).Ov er the past th ree d ecades , th e nu clear in dustry has pro posed dam ping v alues and discuss ed these v alues during v arious m eeting s an d rev iews of licen sing issue s. N uclear industry g roups and licensees ha v e su g g es te d th at th e N R C o ug ht to a cc ep t m or e re al is ti c da m pi ng v al ue s fo r se is m ic d es ig n an d an al y si s of S SC s, in pla ce o f the dam ping v alues prov ided in the orig inal R eg ulatory G uide 1.6 1.St r uc tu r al D am pingI n 1 993, the NR C com pleted an in v estig ation of the ade quacy of orig inal R eg ulatory G uide 1.6 1 structure dam ping v alues and other recom m endatio ns, and reported the results in N UR EG/CR-6011 [R ef. 3]. Data were analy z ed to iden tify the param eters tha t sig nificantly influe nced structure dam ping. Base d o n t ha t st ud y, t he NRC de t e r min e d t ha t th e or i gin a l Re gul a t or y Gui de 1.61 da mpi ng val ue s fo r st r uc t ur e de s i gn were adequ ate bu t requ ired o ne s ig nificant rev ision. S pecifically , R eg ulatory G uide 1.6 1 sh ould disting uish betw een "friction- bolted" and "be aring-bolted" con nection s for steel stru ctures. F riction-bolted conn ections a r e al s o r e f e r r e d t o a s "s l i p-cr i t i c a l" co nn e c t i on s. I n t he s e co nn e c t i on s , t he bo l t pr e l oa d i s hi gh e no ugh to e ns ur e th at f ri ct io n is n ot o v er co m e, a nd th e bo lt d oe s no t e xp er ie nc e sh ea r lo ad in g. R eg ul at or y Position 1 in S ection C of this rev ised g uide prov ides th e up dated structural dam ping v alues.

Rev. 1 of RG 1.61, Pa g e 3 P iping Da m pingI n 1 986, the Am erican Society of Mechanica l En g ineers (AS ME) esta blished C ode Case N-411,"A l t e r n a t i ve Da mp i n g V a l u e s f o r Re s p o n s e Sp e c t r a An a l ys i s o f Cl a s s 1 , 2 , a n d 3 Pi p i n g," i n Se c t i o n I II , Div ision 1, of the A SME Boiler and Pressu re Vessel C

ode [Ref. 4]. The NR C staff use d C ode Case N-411, with certain lim itations specified in R eg ulatory G uide 1.8 4 [R ef. 5], to rev iew operatin g reacto r issue s until C ode Case N-411 expired in 2000. The staff also app rov ed th e us e of alternate dam ping v alues for the G eneral Electric Adv anced B oiling Water R eactor Desig n in 1994 [R ef. 6], Com bustion En g ineering S y st em 8 0+ D es ig n in 1 99 2 [R ef. 7], a nd We st in g ho us e A P 60 0 D es ig n in 1 99 8 [R ef. 8]. R eg ul at or y Position 2 in S ection C of this rev ised g uide prov ides th e pip ing dam ping v alues that resu lted from the sta ff's exp erience with AS ME C ode Case N-411 and app lication rev iews of n ew reactor desig ns.Ele c tr ic al D ist r ibut ion Sys te m Da m pingReg ulatory G uide 1.6 1 d id no t orig inally pro v ide d am ping v alues for cab le tray or cond uit sy stem s. H is to ri ca ll y , th e nu cl ea r po w er in du st ry u se d th e da m pi ng v al ue s fo r bo lt ed s te el s tr uc tu re s fo r se is m ic de si g n of c ab le tr ay a nd c on du it s y st em s. I n th e la te 1 98 0s , h ow ev er , th e N R C s ta ff r ev ie w ed th e re su lt s of the cab le tray test at the Com anche Pe ak Stea m Ele ctrical S tation [R ef. 9]. R eg ulatory Po sition 3 in S ection C of this rev ised g uide prov ides th e da m ping v alues that resu lted from the staff's rev iew of d at a fr om th e C om an ch e P ea k te st [R ef. 1 0] a nd tw o sa fe ty e v al ua ti on r ep or ts [R ef s. 9 , 1 1].He at ing Ve nt ila ti on a nd A ir Co ndit ion ing Duc t D am pingThe dam ping v alues for he ating v entilation and air con ditioning (H VAC) sy stem s are consisten t with the g uidanc e pro v ided for bo lted stee l structu res. B ecause no tests of w elded duct constru ction ha v e be en id en ti fi ed , th e da m pi ng v al ue s ar e th e sa m e as f or w el de d st ee l s tr uc tu re s, a nd R eg ul at or y Posi ti on 4 in Se ct ion C of thi s re vised g uid e pro vides thes e same dam pin g values. I n addi ti on, th e NRC prov ides re lated in form ation on HVAC du ct dam ping in NU RE G/C R-6919 , "Reco m m endatio ns fo r R ev is io n of S ei sm ic D am pi ng Va lu es in R eg ul at or y G ui de 1.61" [R ef. 1 2].M e c hani c al a nd Ele c tr ic al C om pone nt Da m pingNU RE G/C R-6919 [R ef. 12] consid ers g uidanc e in Am erican Society of Civ il En g ineers (AS CE)Stand ard 4 3-05, "S eism ic D esig n C riteria for Structu res, Sy stem s, and Com pone nts in N uclear Facilities"

[Ref. 13], a nd Non-Mandatory A ppen dix N , "Dy nam ic A naly sis Metho ds," to Section I I I , D iv ision 1, of the A SME Boiler & Pressu re Vessels Cod e [R ef. 14]. I n ad dition, N UR EG/CR-6919 [R ef. 12]prov ides re com m endatio ns a nd com m entary on dam ping v alues for (1) contain m ent stru ctures, contain m ent in ternal stru ctures, and othe r Se ism ic C ateg ory I structu res; (2) piping; (3) electrical distribution sy stem s (i.e., cable tray or cond uit sy stem s); (4) HVAC; and (5) m echan ical an d elec trical com pone nts. R eg ulatory Po sition 5 in Section C of this rev ised g uide prov ides th e da m ping v alues that resu lted from the staff's rev iew of this industry g uidanc e.

Rev. 1 of RG 1.61, Pa g e 4 C. R EGU LAT ORY PO SITIONThe f ol lo w in g r eg ul at or y p os it io ns p ro v id e ac ce pt ab le d am pi ng v al ue s to b e us ed in th e el as ti c dy nam ic seism ic ana ly sis an d d esig n o f SS Cs, w here energ y dissip ation is app roxim ated b y v iscous dam ping unless otherw ise sp ecified. D am ping v alues hig her th an th ose prov ided m ay be used if doc um ented te st d at a su pp or t t he h ig he r v al ue s. D am pi ng v al ue s as so ci at ed w it h so il-st ru ct ur e in te ra ct io n an al y si s are n ot w ithin th e sco pe o f this reg ulatory g uide.1.

St r uc tu r al D am ping 1.1 Acce ptab le Str uctu ral D amping V alues f or C onta inment Stru ctures, Con tainment Intern al S tructu res, and Other Seismic C atego ry I Str uctu res 1.1.1 Saf e-Shut down Ear thq uake (SSE)Table 1 prov ides a cceptab le dam ping v alues for the SS E a naly sis.Tab le 1. S SE D amping V alues St ru ct ur al M at er i al D ampi ng (% of C ri t i cal D am p i ng)Rei n f or ce d Conc r et e

7%Rei n f or ce d M as on r y

7%Pre s t r es s ed Conc r et e

5%W el ded St ee l or B ol t ed St ee l w i t h Fr i ct i on Conn ec t i on s

4%B ol t ed St ee l w i t h B ea r i n g Conn ec t i on s

7%Note:

For steel structures w ith a com bin ation of diff erent conn ection ty pes, use the lowe st specif ied dam pin g v alue, or as an alternative, use a "w eighted av erag e" dam pin g v alue based on th e num ber of e ach ty pe present in th e structure.

1.1.2 Oper ati ng-Basi s Eart hquak e (OBE)I f th e de si g n-ba si s O B E g ro un d ac ce le ra ti on is s el ec te d to b e le ss th an o r eq ua l t o on e-th ir d of th e de si g n-ba si s S S E g ro un d ac ce le ra ti on , th en a s ep ar at e O B E a na ly si s is n ot r eq ui re d. H ow ev er , if th e de si g n-ba si s O B E g ro un d ac ce le ra ti on is s el ec te d to b e g re at er th an o ne-th ir d of th e de si g n-ba si s S S E g ro un d ac ce le ra ti on , th en a s ep ar at e O B E a na ly si s sh ou ld b e co nd uc te d. Ta bl e 2 pr ov id es a cc ep ta bl e dam ping v alues for the O BE ana ly sis.Tab le 2. OBE D amping V alues St ru ct ur al M at er i al D ampi ng (% of C ri t i cal D am p i ng)Rei n f or ce d Conc r et e

4%Rei n f or ce d M as on r y

4%Pre s t r es s ed Conc r et e

3%W el ded St ee l or B ol t ed St ee l w i t h Fr i ct i on Conn ec t i on s

3%B ol t ed St ee l w i t h B ea r i n g Conn ec t i on s

5%

Rev. 1 of RG 1.61, Pa g e 5 1.2 Spe cial C onsid eration for In-S tructu re R espo nse Spe ctra Gen erationThe SS E d am ping v alues specified in Table 1 for linear d y nam ic ana ly sis of structures hav e be en s elected based on the expec tation th at the structural respon se attribu ted to load com bination s that inc lude SSE w ill be close to ap plicable code stress lim its, a s de fined in S ection 3.8 of NU RE G-0800[R ef. 1 5].How ev er, there m ay be cases whe re the predicted structu ral resp onse to loa d co m bination s that inc lude SSE is s ig nificantly belo w the ap plicable code stress lim its. Beca use equiv alent v iscous da m pi ng r at io s ha v e be en s ho w n to b e de pe nd en t o n th e st ru ct ur al r es po ns e le v el , it is n ec es sa ry to co nsider that the SS E d am ping v alues specified in Table 1 m ay be incons istent w ith the predicted st ru ct ur al r es po ns e le v el.For structural ev aluation, this is no t a c oncern , b ecause the stresses resulting from the use of d am ping-com patible structural respon se w ill still be less tha n the app licable c ode stress lim its, as d ef in ed in S ec ti on 3.8 of N U R E G-08 00 [R ef. 1 5].H ow ev er , f or in-st ru ct ur e re sp on se s pe ct ra g en er at io n, it is n ec es sa ry to u se th e da m pi ng-co m pa ti bl e structural respon se. C onseq uently , th e follo wing add itional g uidanc e is prov ided for an aly ses u sed to de term ine in-structure respon se sp ectra: (1)

U se th e O B E d am pi ng v al ue s sp ec if ie d in Ta bl e 2, w hi ch a re a cc ep ta bl e to th e st af f wit hout fur the r re view.(2)

Sub m it a p lant-specific technica l basis for us e of dam ping v alues hig her th an th e O BE dam ping v alues specified in Table 2 , b ut no t g reater tha n the SS E d am ping v alues specified in Table 1 (e.g., see N UR EG/CR-6919 , S ection 3.2.3), sub j ect to staff rev iew on a cas e-by-case basis.I n g en er al , f or c er ti fi ed s ta nd ar d pl an t d es ig ns w he re th e de si g n-ba si s in-st ru ct ur e re sp on se s pe ct ra represen t the env elope of the in-structure respon ses o btained from m ultiple a naly ses co nduc ted to c on si de r a ra ng e of e xp ec te d si te s oi l c on di ti on s, it is n ot n ec es sa ry f or c om bi ne d li ce ns e ap pl ic an ts to ad dress this issu e. H owe v er, if plan t-specific seism ic ana ly ses are con ducted for Categ ory I structu res and/or structures not in cluded as part o f the standard plan t desig n, then the ap plicant is exp ected t o a dd r e s s th i s is s ue ac c or di ngl y.

Rev. 1 of RG 1.61, Pa g e 6 2.

P iping Da m pingTable 3 presents the constan t dam ping v alues specified for S SE and OB E (w here required)analy ses o f pipin g sy stem s. These v alues are ap plicable to tim e-history , re spon se sp ectra, and equiv alent s tatic ana ly sis pro cedure s for structural qualification

.T ab le 3. D am p in g V al u es for Pip in g S ys te ms C ategory D ampi ng V al ue S S EO B E > S S E/3 Pi pi n g S y s t e ms 4%3%As an a lternativ e for respon se sp ectrum ana ly ses u sing an env elope of the SS E o r O BE respo nse spe ct ra at al l su ppor t poi nts (uni for m suppo rt m oti on), fre que ncy-dep end ent dam pin g values shown in F ig ure 1 m ay be used, sub j ect to the fo llowin g restriction s:*

Frequ ency-depen dent dam ping sho uld b e us ed c om pletely and con sistently , if at all. (Dam ping v alues specified in R eg ulatory G uide 1.6 1 are to be u sed for eq uipm ent other than piping.)*

Use of the spe cified d am ping v alues is lim ited o nly to respon se sp ectral an aly ses. Acce ptance of the use of the sp ecified dam ping v alues with other ty pes of d y nam ic ana ly ses (e.g., tim e-history ana ly ses o r inde pend ent su pport m otion m ethod) requires further j ustification.

When used for reco nciliation or su pport optim iz ation of ex isting des ig ns, the effe cts of increased m otion on existing clearan ces a nd online m ounted equ ipm ent sh ould be c heck ed.*

Frequ ency-depen dent dam ping is n ot ap propriate for an aly z ing the dy nam ic resp onse of p iping s yst e ms us i ng s up po r t s de s i gne d t o d i s s i pa t e en e r gy by yi e l di ng.*

Frequ ency-depen dent dam ping is n ot ap plicable to pip ing in whic h stres s co rrosion crack ing ha s oc cu rr ed , u nl es s a ca se-sp ec if ic e v al ua ti on is p ro v id ed a nd r ev ie w ed a nd f ou nd a cc ep ta bl e by th e N R C s ta ff.

Rev. 1 of RG 1.61, Pa g e 7 3.

Ele c tr ic al D ist r ibut ion Sys te m Da m pingTable 4 presents the constan t dam ping v alues specified for S SE and OB E (w here required)an al y se s of c ab le tr ay a nd c on du it s y st em s. Th es e v al ue s ar e ap pl ic ab le to r es po ns e sp ec tr a and equiv alent s tatic ana ly sis pro cedure s for structural qualification. The dam ping v alues specified in Table 4 are applicab le to all ty pes of su pports, inclu ding w elded supp orts. The us e of hig her d am ping val ue s fo r ca bl e tr a ys wi t h f l e xi bl e su pp or t sys t e ms (e.g., r od-hu ng t r a pe ze s yst e ms, st r ut-hu ng t r a pe ze sy st em s, a nd s tr ut-ty pe c an ti le v er a nd b ra ce d ca nt il ev er s up po rt s y st em s) is p er m is si bl e, s ub ject to obtainin g N RC rev iew for acc eptance on a case-by-case basis.The analy sis m ethodo log y sho uld c onside r the flexibility of supp orts in determ ining the sy stem respon se to seism ic exc itation.

Rev. 1 of RG 1.61, Pa g e 8 T ab le 4. D am p in g V al u es for E le ct ri ca l D is tr ib u ti on S ys te ms C ategory D ampi ng V al ue S S EO B E > S S E/3 C abl e Tray Syst em 4 M axi m um C ab l e Lo ad i ng 1 E m p ty 2 Spray ed-on Fi r e Ret ar dant or ot her ca b l e-restraini ng m ec ha nism 3 10%7%7%7%5%5%C on du i t S ys t e ms 4 M a x im u m C a b le fi ll 1 E m p ty 2 7%5%5%3%Notes: 1.

Maxim um ca ble load ings, in accordance w ith th e plant design specif ication , are to be utilized in con jun ction w ith th ese dam pin g v alues.2.

Spa re c abl e tra y a nd c onduit, ini tia lly e m pty , m ay be a nal y ze d w ith ze ro c abl e loa d a nd the se da m ping v al ues. (Not e: R e-ana ly si s is e x pec te d w hen put i nto s er v ic e.)3.

Res tr ai n t o f th e free re la ti ve m o vement of th e cab le s in si d e a tr ay red u ces t h e system dampi n g.4.

W hen ca ble loa ding s of le ss-tha n m ax im um a re s pec if ie d f or de si g n c al cul at ions , t he appl ic ant or licensee is e xpected to justify the selec ted dam pin g v alues and ob tain NRC rev iew f or acce ptan ce on a c ase-by-case basis.4.

He at ing , V e nt ila ti on, and A ir Co ndit ion ing Duc t D am pingTable 5 presents the constan t dam ping v alues specified for S SE and OB E (w hen required)analy ses o f H VAC duct sy stem s. These v alues are ap plicable to resp onse spectra and equiv alent static an aly sis pro cedure s for structural qualification

.The analy sis m ethodo log y m ust co nsider the flex ibility of supp orts in determ ining sy stem respon se to seism ic exc itation.T ab le 5. D am p in g V al u es for HV A C D u ct S ys te ms Type of D uc t C ons t ru ct i on D ampi ng V al ue S S EO B E > S S E/3 Pock et Loc k10%7%Compan i on An g l e7%5%W el ded4%3%

Rev. 1 of RG 1.61, Pa g e 9 5.

M e c hani c al a nd Ele c tr ic al C om pone nt Da m pingTab le 6 p re se nt s th e da m pi ng v al ue s fo r m ec ha ni ca l a nd e le ct ri ca l c om po ne nt s, w hi ch a re ap pl ic ab le to p as si v e su bc om po ne nt s th at c an b e se is m ic al ly q ua li fi ed b y a na ly si s. A ct iv e su bc om po ne nt s do n ot r ea di ly le nd th em se lv es to s ei sm ic q ua li fi ca ti on b y a na ly si s, a nd r eq ui re q ua li fi ca ti on b y te st , as d es cr ib ed in S ec ti on 3.10 o f N U R E G-08 00 [R ef. 1 5].T ab le 6. D am p in g V al u es for Me ch an ic al a n d E le ct ri ca l C om p on en ts C ompone nt Type D ampi ng V al ue S S EO B E > S S E/3 M o t o r, Fan, and C

o m p res sor H o usi ngs (p ro te c tio n , stru c tur a l sup p o rt)3%2%P ressu re V esse l s, H ea t E xc ha ng ers, an d P um p an d V alve B o d i es (p re ssu re b o u n d a ry)3%2%W el d ed Ins t rume nt R acks (s tru c tur a l sup p o rt)3%2%El ec t r i ca l Cabi n et s , Pan el s , a n d M ot or C o ntro l C en t ers (M C C s)(p ro te c tio n , stru c tur a l sup p o rt)3%2%M et al A t m o spheri c Storage T

anks (contai nm ent , pro t ect i o n) - I mpu l s i v e M ode - Sl os h i n g M ode 3%0.5%2%0.5%

Rev. 1 of RG 1.61, Pa g e 10 D. IMP LEM ENT ATIONThe purp ose of this section is to prov ide in form ation to ap plicants and licensees reg arding th e N R C s ta ff's p la ns f or u si ng th is r eg ul at or y g ui de. N o ba ck fi tt in g is in te nd ed o r ap pr ov ed in conn ection with the issu ance of this g uide.Exce pt in those cases in w hich an a pplican t or licensee propo ses o r has prev iously estab lished an a cceptab le alterna tiv e m ethod for co m ply ing w ith sp ecified portion s of the N RC's reg ulations, th e N R C s ta ff w il l u se th e m et ho ds d es cr ib ed in th is g ui de to e v al ua te (1) s ub m it ta ls in c on ne ct io n w it h applicatio ns fo r con struction perm its, sta ndard plan t desig n ce rtifications, op erating licens es, early site perm its, a nd com bined licenses;

and (2) su bm ittals from op erating reacto r license es who v oluntarily pro pose to initiate sy stem m odification s if th ere is a clear nexu s be tween the propo sed m odification s an d the sub j ect for whic h g uidanc e is prov ided herein.R EG U LA TO R Y A N A LY SI S / B A C KF IT A N A LY SI SThe r eg ul at or y a na ly si s an d ba ck fi t a na ly si s fo r th is r eg ul at or y g ui de a re a v ai la bl e in Draft Reg ulatory G uide DG-1157 , "Dam ping Values for S eism ic D esig n o f N uclear Pow er P lants"(R ef. 1 6). Th e N R C is su ed D G-11 57 in O ct ob er 2 00 6 to s ol ic it p ub li c co m m en t o n th e dr af t o f th is Rev ision 1 o f R eg ulatory G uide 1.6 1.

A ll NR C r eg ula tions li st ed her ei n a re a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on t he NR C's 3 public W eb si te , a t http://w w w.nrc.g ov/re adi ng-r m/doc-c olle ct ions/c f r/pa rt050. C opie s ar e al so av ai la ble f or i nspe ct ion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room a t 11555 Roc k v ill e Pike , R ock v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555; te le phone (301) 415-4737 or (800) 397-4209; f ax (301)415-3548;

em ai l PDR@nrc.g ov.A ll re g ula tory g uide s lis te d he re in w er e publis hed by the U.S. Nuc le ar Re g ula tory Com m is si on or its pre dec es sor , 4 the U.S. A tom ic Ene rg y Com m is si on. M ost a re a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on the N RC's publi c W eb si te , a t http://ww w.nrc.gov/readin g-rm/do c-collection s/reg-g uid es/. S ing le c opie s of re g ula tory g uide s m ay a ls o be obta ine d f re e of c har g e by w rit ing the Re produc tion and Di st ribut ion Se rv ic es Se ct ion, A DM, U SN RC , W as hing ton, DC 20555-0001, by f ax to (301) 415-2289, or by e m ai l t o DI ST RI BU T IO N@nrc.g ov. A ct iv e g uide s m ay a ls o be purc has ed f rom the N at iona l T ec hnic al Inf orm at ion Se rv ic e (N T IS). D et ai ls m ay be obta ine d by c onta ct ing N T IS at 5285 Port R

oy al Roa d, Spr ing f ie ld, Virg inia 22161, onl ine a t http://w w w.nti s.g ov , by te le phone at (800) 553-N T IS (6847) or (703) 605-6000, or by f ax to (703) 605-6900.

C opie s ar e al so av ai la ble f or ins pec tion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room (PDR), w hic h is loc at ed at 11555 R ock v ill e P ike, Rock ville, Mary land; the P DR's m ailing address is USNRC

P DR, W ashington , DC 205 55-00 01. T he P DR ca n a ls o be re ac hed by te le phone at (301) 415-4737 or (800) 397-4209, by f ax a t (301) 415-3548, a nd by e m ai l to PDR@nrc.g ov.A ll NU RE G-s er ie s re ports li st ed her ei n w er e publis hed by the U.S. Nuc le ar Re g ula tory Com m is si on. C opie s ar e 5 ava ilable f or in spection or copying f or a f ee f rom the NRC's Pu blic Docume nt Ro om at 115 55 Rockv ille P ike, Roc k v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555; te le phone (301) 415-4737 or (800) 397-4209; f ax (301) 415-3548;

e m ai l PDR@nrc.g ov. C opie s ar e al so av ai la ble a t c urr ent ra te s f rom the U.S. G ov er nm ent Printi ng O f f ic e, P.O. Box 37082, W as hing ton, DC 20402-9328, te le phone (202) 512-1800;

or f rom the N at iona l T ec hnic al Inf orm at ion Se rv ic e (N T IS) a t 5285 Port Roy al Roa d, Spr ing f ie ld, Virg inia 22161, online a t http://w w w.nti s.g ov, by te le phone at (800) 553-N T IS (6847) or (703) 605-6000, or by f ax to (703) 605-6900.

NU RE G-0800 a nd N UR EG/C R-6919 a re a ls o a v ai la ble e le ct ronic al ly thr oug h the El ec troni c Re adi ng Room on the N RC's publi c W eb si te , a t http://ww w.nrc.gov/ reading-rm

/do c-collection s/nu regs/.Cop ies m ay be obt ained from the A m erican Society of Mechanical Engineers, T

hree P ark A venue, New York, NY 6 10016-5990.

Phone (212)591-8500; f ax (212)591-8501;

w w w.a sm e.org.Rev. 1 of RG 1.61, Pa g e 11 REF ERE NC ES 1.

U.S. Cod e of Fede ral R egulatio ns , Title 10 , P art 50 , "Dom estic L icensing of Prod uction and Util izat ion Faci li ti es," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.3 2.

Reg ulatory G uide 1.6 1, "Dam ping Values for S eism ic D esig n o f N uclear Pow er P lants,"U.S. Atom ic E nerg y C om m ission, Washin g ton, DC , O ctober 1973.4 3.

NU RE G/C R-6011 , "Rev iew of S tructure Dam ping Values for E lastic S eism ic A naly sis of Nuc lear P owe r Plan ts," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , March 19 93.5 4.

"AS ME B oiler an d P ressure Vessel C ode, C ode Case N-411-1, Alterna tiv e D am ping Values for R espon se S pectra Ana ly sis of Class 1, 2 an d 3 Pip ing ,"Section I I I , D iv ision 1, Am erican Society of Mechanica l En g ineers, N ew York , N ew York , F ebruary 20 , 1 986.6 5.

Re gul a t or y Gui de 1.84 , "De s i gn, Fa br i c a t i on , a nd Ma t e r i a l s Co de Ca s e Ac c e pt a bi l i t y -ASME Se ct ion I I I ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.3 6.

NU RE G-1503 , "Final Safety Ev aluation Rep ort R elated to the C ertification of the A dv anced Boilin g-Water R eactor," U.S. N uclear Reg ulatory C om m ission, Washin g ton, DC , July 19 94.4 Cop ies a re av ailable f or in spection or copying f or a f ee f rom the NRC's Pu blic Docume nt Ro om at 115 55 Rockv ille P ike, 7 Roc k v ill e, MD; t he PDR's m ai ling a ddre ss is U SN RC PDR, W as hing ton, DC 20555 (te le phone: 301-415-4737 or 800-397-4209;

f ax: 301-415-3548; e m ai l: PDR@nrc.g ov).Cop ies m ay be purch ased f rom the A m erican Society f or Civil Engineers (A

SCE), 1 80 1 A lexa nd er Be ll Drive, 8 Re st on, VA 20190 [phone: (800) 548-A SCE (2723)]. Purcha se inf orm at ion i s av ai la ble thr oug h the A SCE W eb si te at http://w w w.pubs.a sc e.org.Dr af t R eg ula tory G uide D G-1157 i s av ai la ble e le ct ronic al ly unde r A cc es si on #ML 062680189 in the N RC's 9 A g enc y w ide D ocum ent s A cc es s and Ma nag em ent Sy st em (A DA MS) a t ht tp://w w w.nrc.g ov/re adi ng-r m/a dam s.htm l. Copi es a re a ls o a v ai la ble f or i nspe ct ion or c opy ing f or a f ee f rom the N RC's Public D ocum ent Room (PDR), w hic h is located at 115

55 Rockv ille P ike, Rock ville Mary land; the P DR's m ailing address is USNRC

P DR, W ashington , DC 20 55 5-0 00 1. The PDR can also be reac hed b y telepho ne at (301) 415-47 37 or (80 0) 39 7-4 20 9 by f ax at (301) 415-3548, a nd by e m ai l t o PDR@nrc.g ov.Rev. 1 of RG 1.61, Pa g e 12 7.

NU RE G-1462 , "Draft Safety Ev aluation Rep ort related to the D esig n C ertification of the Sy stem 80+Desig n," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , S eptem ber 1 992.4 8.

N U R E G-15 12 , "F in al S af et y E v al ua ti on R ep or t r el at ed to C er ti fi ca ti on o f th e A P 60 0 S ta nd ar d Desig n," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , S eptem ber 1 998.4 9.

NU RE G-0797 , "Safety Ev aluation Rep ort R elated to the O peration of Com anche Pe ak Stea m Electric Station, U nits 1 and 2," S upplem ent N o. 16, U.S. N uclear Reg ulatory C om m ission, Washing ton, DC , July 19 88.4 10.

Ware, A.G., a nd C.B. Slau g hterbeck , "A Surv ey of Cab le Tray and C ondu it Da m ping R esearch,"I daho N ational Eng ineering La boratory , R eport No. EG G-EA-7346 , R ev. 1 , p repared for the U.S. N uclear Reg ulatory C om m ission, Washin g ton, DC , A ug ust 1 986.7 11.

NU RE G-0847 , "Safety Ev aluation Rep ort for Watts B ar N uclear Plant, U nits 1 and 2,"Sup plem ent N o. 8, U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , January 19 92.4 12.

N U R E G/C R-69 19 , "R ec om m en da ti on s fo r R ev is io n of S ei sm ic D am pi ng Va lu es f or th e S ei sm ic Dam ping Values in R eg ulatory G uide 1.6 1," U.S. Nuc lear R eg ulatory C om m ission, Washin g ton, DC , N ov em ber 2 006.4 13.

A m er ic an S oc ie ty o f C iv il E ng in ee rs , A S C E S ta nd ar d 43-05 , "S ei sm ic D es ig n C ri te ri a for S tructures, Sy stem s, and Com pone nts in N uclear Facilities," R eston, VA, 20 05.8 1 4.

A me r i c a n So c i e t y o f M e c h a n i c a l En gi n e e r s , "B o i l e r a n d Pr e s s u r e V e s s e l Co d e ," Se c t i o n I II , Di vis i on 1, Non-M a nd a t or y App e nd i x N, "D yna mic Ana l ysi s Me t ho ds ," Ne w Yo r k, Ne w Yo r k, 2004.5 15.

NU RE G-0800 , "Stand ard R ev iew Plan for the R ev iew of S afety A naly sis R eports for N uclear Power Plan ts ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.4 16.

Draft Reg ulatory G uide DG-1157 , "Dam ping Values for S eism ic D esig n o f N uclear Pow er Pla nts ," U.S. Nucl ear Regulat ory Com m is si on, W ash ingto n, DC.9