Regulatory Guide 1.27
| ML13038A084 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1974 |
| From: | US Atomic Energy Commission (AEC) |
| To: | |
| References | |
| RG-1.027, Rev. 1 | |
| Download: ML13038A084 (4) | |
- REGULATORYýGUIDE:1.27
_UT1MA~TE'H EAT S!NK
A. ;NTOUT~
-General -De ,Iec
"~Cooling 'Water" of Appendix A,"1~ na.'"to l'O:CFR'Part' "unJt
50, M'IJicensing tiization Facilotns," 'acc
.requires, in part i'dancyimn*features-be *the e:.:to assure -that sits it:equIesý I: .pan, LlUnIsIT*u tures, *snuiaiown cc Ind; ,co onenLs _important to safety ibe ,one untW :the IWithst Ithe:,effects ?of 'natural 'phenomena that accidei
)ss , of pability 'to -perform their "safety *shutdowni .a
"describes~>a basis acceptable to t'he .ma'intaini'all'
Thej.cara*o or.'the sink- sho
-itiy
,p'ovide'ýe66liitabot hafor the pefio'
nts. The Advisory -Cuminittee on R~.eactor oevaluateithce sjtuatinand for, the p has been consulited concelrnginghis guide and to take' corrective actio
n. A pej
-ed imithe fegulatory~position. considered- to be adequate -.or
'addition:-. roceCur es shoild 'be-avai]
lter -s,ýstenvz1s Mnat compiex' oi ~waLT .':Sources',
- i]l necessary retainiing 'ýstiuctures (e.g.,, a "pond cnai -a -lu-cdy. suvvly'M w t'cl -IýSeeabd m4; or -a river- with its'idam) - and the canals.or design bisis 'temperatuires of "safet/y-rel nnecting the sources not including,
,with.but' 'are not exceeded.-FoT heat sinks where water system intak-structure& 'for -a -nuclear' ,be timited anid/or 'thelen peyrat'uireof'I
tL, f coolinrg towersor '*ortions tfereof -are "from 'the sink bcrjcitic;abje~j becmy
'capability 'of the'
ions. -tAing into accoL
ecuiniment and li
'hesinik safety ziyflda on "mybetpfovided by ',Where -'ti'rf ru iaural or ýman made 'features More functions~~~~ b
- han one water .
he-anIs my or'cndiuits ~ are require;aIprt ,bflhe sinkrat-east Two should,'ýb-e]*provided,ýeienif only one source -may be involved, in the ultimate, ýheat sinki source of water has been demonstrated'to-be ade'quate;
'complex,;in performfingithese functions unde*rdifferentm -However, -iisingle canal may be-acceptable ift.s.....isfies.......
conditions, Because of* the"ýimportance 'of ýthe sinkto- The four conditions above. Where the sink i clu~des; -or safz*,y, these functions should be asured during and than ýone source of water he*
- ndividmuaatefi:so-rc -. es'
foillowingAhe-mnostsevere natural phenomnaempostulated may have -different des'ign requiremen'ts.',Mulitipwater'w Sfor,.te :siteýi(e~g the'-.safe ýshutdown, earthquake, ,design - sources, including their associated x iretaining sui6 urs
'basis-'totnado 'hurifiane,,flood, or diought?ý). ln addition' - - and'required canals ýand' conduits, shoul~d~bese' _'rated, ~'
thc~sifk safety functions ýshould'be assured,ýuriing ot~her -and-protected so-thatfailure of-any-one--wýillntndc applicable stread vnsta my-b-cue'by failure -n.zany 'other 'that woudld- pred~udeitauoomphishing natural phenom'na such as river blockage;. river the safdctfunctions of the sink.* The;ccompiex 1(ibut not divex'ýsion or'rreservoli depletion, or if applicable, other - necessarily its individialj/ea-tiuý.S) :rust Jberca0Able of accidents such a.s'transportation-accidentsrinvolving ship. withstandii eac -of th 'm~'e iat iral, phenmena
'collisions. airplane. crashes, or - oil .spills .-and fires. -'expected, otlher s-ite-rielat-ed .evenrts, reasonable
6 R, *a. combntieoo-s -of :less sever6;_atura1 ý'anL- ions of rnaturalj nomena.and /ior.ýste-.relatd.etI.,l
-:coibina
.acn ,or -. e nts;, :nd- a .bu le failure' of ; ,man ae stmact.ural-. .... *.* -,
- .onider-d extent,needed fora-consistent, vel'of' $features i*thout y'ossof 0 capability of -the sirik 'to -
-,
conservitism; for ýexaniple, -such- coijibinat-jons should be. - accompilish -its.,- safety -functions.-'The. rmostl isevere- evlntý ~iics~ilee1e'rbbiro-hieitn at -*he,_same4'imecand 'haiing -ignifcariit consequences is- phenomena .may be' considered rto occur undepen dently and -not simultaneouslyv.lnaddition the minglefafilure&of - .
, comparabie to that associated wi -the most --severe . -.man-made st'r-uctural features need not be c'onsidCeedALo -
phenomena..- occur-sirnuiltaneously with severe natural phenomena or
Th fe;h tld'bea -high 'level ~o~fýassurance 1that:the--sieeledvnt, - -
.. waterces< of thesink* Willbe'availableht hen'needed, . For -example, it,-would be acceptabeif Water'Soure"'....
For 'natural ,sources.historical experienrceindicates'that -. No. I-. (say a man-made pond with a dam) and
'river blockage or :diversion may -be',possible, as well as connecting conduit -were capable.of withstanding thc ,.*.
changes'in -,ocean ior lake levels as -a result -of -severe safeeshutdown earthquake, tornado, and drought and -'
inalural :.events. For 'man-made .portions, par.ticularly 'Water ,SourdceNo..22(say -3river-With an: existing dam)
structures 'above 'ground, failures -are -not uncommon. and its-connecting conduit were ýcapable-,oof:withstznlding ,ýtý
ýBecause of ýthese fatos cosdrto'hudb~ie the 'probable. maximium flood -,How Ahe tlecomiplex~as
,
4theksjiiik 6cmprisi1g-t ' *aaewhoue r 'mustachalso -,be cpable:, of hsandiii; an
0,igtteast.ýtwoý,a- asucee wwieinut. tc d-fny':-
kcJ fp fonk~fn fnls it -a-reasobf probable" zorfiibination ~ofntir]o
',,can 'bdemonstrated'-hit there is an ictremelyi lowv accidental* phenomena .without loss of the sinik
'probability of losing ~ the capabilitiy :of a sinle source functions.
-For 'thotse -cases in:-whichlan aplic*in believes a single S, waiter source -may be acceptable it should be The ultimate heat sink, as a -comp]ex, should be demostated that the source can withstand, without shown to be highly reliable' ,tshig nnh tger S- -- lo~ss ~ofrthe ssink~ safety functions -the following -events: -'conditions -are satisfied. 'For-.example, x onsideritWater- s¢:vere, e~fai atura mhenomiena .efaected,ta.ken, ,Source satbove Noa- nig*: 'Suchcon'difionsewo*and'included
- howi gufcnlyt haý,Crtii) .. .:
~~~~ ~~.site-,Teiated eins' at~hve . thie river canLnotbdvetdo4lke 7
-ocd ;ibed or-tht.-i ocunayuigt ep ,tlfa ,' affect the availability ofv-water at the connecting reasonably -Probable, combinations of less severe ýnatural conduits; (2) no, serious ýtransportation -accidents, have
- pheno mena :and/or sile-related events, and"(4)--a single occurred-or canbe reasonably expected-, and (3) the dam -
failuieof, man-made Struct-ural features. -Inapplying this- a designed to appropriately conservative"s requirements.
"single ýfailure, various mechanistic failure modes 'has functioned properly over, it-s lifetimrel, and (balsed oln
. h - be-hpostulated -One may choose 'to* assume a oprojectn te b will fnction o ee'colb !bnt-:tsAsoi :eme*he!sa i.-' properly -for the Aifetimeonof- the ~nncleori.powero its.. it
' "
- rev qir
- ... i~e-asum86i iiw owveosa h..neuneso s, but ths sntnecessaf! ~otua eu r~e:,l* ,...... _serves.
Phe. -Compliance with~'these, tt suceconditions
-ohnp~iayo. wouldý
,.ae,*e1 ino r-
'ma4~~ratue o-~- d 6diin i -hixeitd ioever,-remo-61th'neediforf another sour oloIng ce D
.- - ffect of forces in~mne :tthe ti e of riip'ture) should water if a' sigefiueotedmcudr'lýi'oiv
-be assurnedý however, 'it is notr-'ecessar-ily. required that the coln 'iait fti, uco wt el one. assume th dan iitgrates instant'aneously with- constructed-features, not ~required to ýbe desingedt A
'total>-Is offnto---s-nte eapethe withstand 'the safe' shutdown earthquake or the -Probable' --
consequences of a postulated slide of earthen canal walls maximum -flood ,shotild at -least,'be designed- and- ':
should' be assuredL; however, it is not necessarily constructed to withstand;,the effects of the maximum rrequxe!ire at~ba neý assume wate~r~fow ceases ,completely, , .earthquake'deterri-mined~oti -the basis of historic seisnCity-~
1'. 7-
'*d*£ .&
- ,' : * b : ." ,: :.A , ; . gf.= , "5: " " . ; , *) :: f : '"' = : , ': , ,r: ,* ;* -*}r .j
a- iea&WtTfo bsdon~'everehiistorical
-fi'7 events in4ihe ýregicn. i speeds 'occurring' sirmltaneously results in the in:~
-maximum-amourjt -f-evaporafio nand drift loss.
Ihe :importance of -the sink to safety-is such that, if, rduring plant operation, the -cappability ok the si . -is b. -Analysis-of-the temperature problem should use -
" ,iiretened,: as- for example 4t6 permit riecessary the ýworst I--day and -w'orst- 30-day .'periods of maintenance or as a result of damage, restrictions should meteorological record in -the region . :ulting tre in
-be -lLaced p rniriimum '-heat'transfer to .the- atmosphere"and maximum on plant operation.- The -technidal
'specificafio'ns'-should statae'Thea-c ti ons Io-b etakeni inthe plant intake -temiperature. .. urthe',. 'thewos l-y
- event ,-.thc-,.,required capability -of -tfie--srik is -temporarily -period ofrecod-Soud~hld- be assumred'tb Te-the fiksday CI f unavailable during ;plant ;operation. For example, the -the worst .30-day :period -of ',record. For'transient temperature -analysis, diurnal variations intemperature -.
Atechnical s pecifications. should require-, that (1) the
ýClommission 'be -notified-Af the sinkd does -not should :be used fo6r the 1-day and 30-day periods' of satisfy -the analysis. These -variations are readily- estimated: from liniiting conditioni for -opetation-and,(2)-if its capability cannot be restoredto- this condition,.within z reasonable 'local-,weather;,-r~ecord~s. App~tlicants -should-1be ;assufredthat either a-normal-oreniergency shutdown during theý worst
.period oftime, all-units- served:by the sink -L -hut down
- {7
- -....and--emainshut -1-day and 30-day period -;of -record will not iresult in
,a;
donunfil:this ctap~biliti: is-,x es tore d.- -
plant intake water temperatures-'exceeding Aesin basis temperatures.--
C. REGULATORY POSITION
-
- -The above -analysis related .to 'the,30-day cooling -
1. The ualtimate bheat sink should -ýbe capable 'of -supply .and .the excess,* tempnerature should 'include
.providing' sufficient -cooling for at, least :30 days to -- sufficient 'information
'(a)
permit simultaneous safe shutdown and cooldown of all ',to 'substantiate t'he- assumrpt'ions- and-analytical -methods used- hismnformation should, nuclea-reactor units that it Serves and to maintain'them in, aý'.ife:shutdown -condition and- (b)-ntd*vnt Of an-; -include' actual, erformance ýdata -for a'siiriil4),coiluing K
- mnethod:operating 'under-load ýnear rthe specifi:deSg "...
accdent, imnc'uie, uii~t:;tolimit tbe -e'ffectý oftha-ajccidu~nf y,,to 'errhiit simultarcous and safeshutdown ofe ~conditions,-or justification, that-- conserva-tive -drift 'loss
-ri:d'" heat transfer viues'h ,,'eb'eniused. , - -:
remaining -units, sand to maintain them in a safe shutdown.aondition-.-procedures .for:assuringa continued,
- A co6ling capacity. of less than 30 days may be
- capabiity*-after 30.days should~beavailabl
e. acceptable
=e if-it -can' be:.demonstrated :that,, replenisiiment: .
.*r n" -~f O LL~1~gLm W '* 4Lr,I .:.u.pp1y. -can oe,-" 'erJrecr5o-to, - -'*:*'
-""
..... c.ent 'conservatism shouldbe provided to assure assure the 'continuous~capabili' *f the- *in
'that a 30-day- cooling supily is -available and that design . its ,s- et-y-functi ito -perfor'..
iiinto, *nofg theont;t avabilit e y
£baJs-* te-mperat uresr't* f'sfety--'elated,:equipment are -not - of replenishi ent.equipment'and 'limitations that may be
" exceeed.'
' -l-Fr "heat, sinks where -the iipply Vmay',
be -imposed on Treedom .followng of--,.movement"
limited and/or the 'temperature of plant intake -water
-
- an accident or-the occurrence of severenatural phenomena. -
from the sink may eventually become- critical (. -..
ponds,*,lak-es, -cooling -towers, - or --other' sinks -where 2. 'The ultimate'heat-sink complex, -whether
-
composed Srecirculation between 1lant .cooling wa*teidischarge and ' -.ofsingbeTormultiple water.,-sources, shouldbe catpaileo*o intake -can occur), transient analyses -of.supply-and/or withstanding, without loss of *fthe sink-, saet functpnof :" -~ I- -'
te:
emperature should be-performed. using the folowing: specified in regulatory . position C I, the following - -
'- - - " ' ,events'. -
at., A~nalysis sup-porting
-vailabi.ity 'the a,. of a 30-day -
cool ing.ýsuppl* should be: based. oii historical'region*al a. The most severe natural phenomena expected measurements combining the -worst irecorded 30-day takei individually, aprib:per'ý*30-day average) of maxlinumrdifference -between dry
- "
temperature
, and .dewpoint ..temerature,. AT,-- -b. -The -site-related- events' .(eg:,
.and .the..ihest wind speeds recorded during the same transportation - !
accident, river-diversion) *that historically have ocdutrredý,2.
30-day ~period ýsuch-Ahat the combination of IoT and, orhat may'occurduring the-plant-lifetime, . ..
........
,smallsallo*w,:eli'TC . .. . .eas .. na.ly nds,..&. se' r naturalphenomena 'able --combinationsevents,
2ndfor-site-related 'of less, Mayi"be-madc, or-*-the analytical -techniques andicomputer S-' prgams ",Contained iq "Generic Emergency- Cooling Pond . "
, Analy'sis,--"COO
- 2224-1 May'1972 -October 1972,preparedfor -- d.. -A single -failure of man-made struct ural -'
the' USAEC by :Uni'ersity of Pennsylvainia, School of features.
. Engiee-in.and App-lited Science, Civil Engineering, Philadelphia,
- - J*.Pennsylvania 719I04- For sinks other than-small shallow nooling - 3.* The -ultimate iheat .sink.should consist of a least two' --
ýýde ion Dmnuaransien.
- - .analyses, should.,:be performed to sources of.water,, including-their--retaining st~uctures1 -
d/ortm'imor,
' "u mrnintakewater. -,eacl-,w th the',cp~abiity -to perform the safety fn ct-ions -'
-I.
spcfe-i reuator~yposition- C.-l. above, rýitcT
-' - p,. - -
31 -
DC GcmtM 0 Sta ed that thicm is an extremcly 'low failure of any one1will not inducefaihiueof.t ptobability of losbig -,ie capabilhtytof -i single source.
fci'her should be a lattwo aqueducts connecting the SOurce('s)4.'ith thc intake structures of the-nuclear power 4. The technical.:specifjica;tiofs u.nts, unless. it cqan be demonstrated that 'Ihere ..is an include ,provisions for actions :to c~treme~ly'ow probabilityvthat'a ,singleaqueduct can faIil :tha. conditions 4hrea~ten: pýt i~dgil entirelv-'ýs a'T6 Wi of natra peioea.1,Iwae Ibe- Wi-niate, heat..sink or -IllieI'
sorces and their Lassuyciated aqueductSs hiouldbb-highfly 'satisfy reg ulat ory. posit ionsi:C..f- diaiendsholdbc separ-ated and pro tected~such' that operation.'
~';' p'.
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