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 Appendix A,"1~50, M'IJicensing.requires, in part"~Cooling
'Water" of na. ' "to l'O:CFR'Part'
tiization Facilotns,"
e:.:to assure -that sits ,Iec"unJt'acc*the Ind; ,co IWithst)ss , of it:equIesý
I: .pan, LlUnI tures, onenLs _important to safety ibe I the:,effects
?of 'natural 'phenomena pability 'to -perform their "safety"describes~>a basis acceptable to t'he*snuiaiown cc ,one untW :the that accidei*shutdowni .a.ma'intaini'all'
nts. The Advisory -Cuminittee on R~.eactor has been consulited concelrnginghis guide and-ed imithe fegulatory~position.-itiy or.'the sink- sho ,p'ovide'ýe66liitabot hafor the pefio'oevaluateithce sjtuatinand for, the p to take' corrective action. A p ej considered- to be adequate -. or'addition:
-.roceCur es shoild 'be-avai]RB: i]l lter -s,ýstenvz1s Mnat compiex' oi ~waLT .':Sources', necessary retainiing
'ýstiuctures (e.g.,, a "pond m4; or -a river- with its'idam)
-and the canals.or nnecting the sources ,with.but'
not including, water system intak-structure
& 'for -a -nuclear'tL, f coolinrg towersor tfereof -are cnai -a -lu-cdy. suvvly'M w t'cl -IýS eeabd design bisis 'temperatuires of "safet/y-rel
'are not exceeded.-FoT
heat sinks where ,be timited anid/or 'the len peyrat'uireof'I"from 'the sink becmy bcrjcitic;abje~j
'capability
'of the'-tAing into accoL ecuiniment and li ions.
'hesinik safety on "mybetpfovided by ',Where -'ti'rf ziyflda functions~~~~
~ my b he-anIs or'cndiuits are require;aIprt ,bflhe ru iaural or ýman made 'features More one water .sinkrat-east Two 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 -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; -orthese functions should be asured during and than ýone source of water 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 sui urs 6'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 The;c compiex 1(ibut not d ivex'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. combntieo o-s -of :less sever6;_atura1
ý'anL- -:coibina ions of rnaturalj nomena.and
/ior.ýste-.relatd.etI.,l
.acn ,or -. e nts;, :nd- a .bu le failure' of ; ,man ae stmact.ural-.
.... -,*.onider-d extent, needed fora-consistent, vel'of' $features 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 phenomena .may be' considered rto occur undepen dently at
'haiing -ignifcariit consequences is- 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 orTh fe;h tld'bea -high 'level ~o~f ýassurance
1that:the--sieeledvnt, --.. waterces<
of the 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, pa
r. ticularly
'Water ,SourdceNo..2
2(say -3 river-With an: existing dam)structures
'above 'ground, failures -are -not uncommon.
and its-connecting conduit w ere ýcapable-,oof:withstznlding
,ýtýýBecause of ýthese fatos cosdrto'hudb~ie the 'probable.
maximium flood -,How Ahe , tlecomiplex~as
4theksjiiik
6cmprisi1g-t r ' *aaewhoue
'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 l owv phenomena .without loss of the sinik'probability of losing ~ the capabilitiy
- of a sinle source functions.-For 'thotse -cases in:-whichlan 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' ,t shig nnh tger:howi g haý,Crti S- -- lo~ss ~ofrthe ssink~ safety functions -the following -events: -'conditions -are satisfied.
'For- .example, x onsideritWater- s¢: e~fai vere, atura mhenomiena .efaected, ta.ken, ,Source Noa -satbove 'Such i) .. .:~~~~ ~~.site-,Teiated eins' at~hve .thie river canLnotbdvetdo4lke ufcnlyt 7-ocd ;ibed or-tht.- i nay ocu uigt e p ,tlf a ,' 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. -In applying this- a "s designed to appropriately conservative requirements."single ýfailure, various mechanistic failure modes 'has functioned properly over, it-s lifetimrel, and (balsed oln h -.be-hpostulated -One may choose assume a oprojectn te b will fnction v ... i~e-asum8 owveosa s, but ths sntnecessaf!
eu ...... Phe. -ohnp~iayo.
tt suce o ee'colb !bnt-:tsAsoi i.-' ' properly -for the Aifetimeonof- the ~nncleor
i. powero
..its it ":re qir 6i iiw h..neuneso
~otua , _serves. -Compliance with~ 'these, conditions wouldý ino r-'ma4~~ratue o-~- d 6diin i -hixeitd ioever,-remo-61th'neediforf another sour ce D oloIng.- -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-: :
- b : " :.A gf , .& ,' .,: , ; ..= "5: " " .; , :: f : '"' = : , ': , ,r: .j a- -fi'7 iea&WtTfo bsdon~'everehiistorical events in4ihe ýregicn. in:~Ihe :importance of -the sink to safety-is such that, if, r during plant operation, the -cappability ok the .si -is" ,iiretened,:
as- for example 4t6 permit riecessary maintenance or as a result of damage, restrictions should-be p -lLaced on plant operation.-
The -technidal
'specificafio'ns'-should statae'Thea -c ti ons Io-b etakeni in the* event ,-.thc-,.,required capability -of -tfie--srik is -temporarily unavailable during ;plant ;operation.
For example, the Atechnical s pecifications.
should require-, that (1) theýClommission
'be -notified-Af the sinkd does -not satisfy -the liniiting conditioni for -opetation-and,(2)-if its capability cannot be restoredto- this condition,.within z reasonable.period oftime, all- units- served:by the sink -L -hut down;{7:-....and--emainshut ,a; donunfil:this ctap~biliti:
is-,x es tore d.-C. REGULATORY
POSITION 1. The ualtimate bheat sink should -ýbe capable 'of.providing'
sufficient -cooling for at, least :30 days '(a) to permit simultaneous safe shutdown and cooldown of all nuclea-reactor units that it Serves and to maintain'them in, aý'.ife:shutdown -condition and- Of an-;accdent, imnc'uie, uii~t:;tolimit tbe -e'ffectý
oftha-ajccidu~nf y, ,to 'errhiit simultarcous and safeshutdown ofe remaining -units, sand to maintain them in a safe shutdown.aondition-.-procedures .for:assuringa continued,
30.days should~beavailable.
i speeds 'occurring'
sirmltaneously results in the-maximum-amourjt -f-evaporafio nand drift loss.b. -Analysis-of-the temperature problem should use -the ýworst I- -day and -w'orst- 30-day .'periods of meteorological record in -the region .tre :ulting in rniriimum
' -heat'transfer to .the- atmosphere"and maximum plant intake -temiperature.
..urthe',. 'thewos l-y-period ofrecod-Soud~hld- be assumred'tb Te-the fiksday CI f-the worst .30-day :period -of ',record.
For'transient temperature -analysis, diurnal variations
-.intemperature should :be used fo6r the 1-day and 30-day periods' of analysis.
These -variations are readily- estimated:
from'local-,weather;,-r~ecord~s.
App~tlicants -should-1be
- assufredthat either a-normal-oreniergency shutdown during theý worst--1-day and 30-day period -;of -record will not iresult in plant intake water temperatures-'exceeding Aesin basis tem peratures.--
---The above -analysis related .to 'the,30-day cooling --supply .and .the tempnerature should 'include--sufficient
'information
',to 'substantiate t'he- assumrpt'ions- and-analytical -methods used- hismnformation should,-include'
actual, erformance
ýdata -for a'siiriil4),coiluing K-mnethod:operating
'under-load
ýnear rthe specifi:deSg
"...~conditions,-or justification, that-- conserva-tive -drift 'loss-ri:d'" heat transfer viues'h
,,'eb'eni used. , --:-A co6ling capacity.
of less than 30 days may be acceptable if-it -can' be:.demonstrated
- that,, replenisiiment:
.-~f =e n" O LL~1~gLm W 4Lr, I .:.u.pp1y. -can oe,-" 'erJrecr5o-to, --"" .....c.ent 'conservatism shouldbe provided to assure assure the 'continuous~capabili' the- *in ito -perfor'..
'that a 30-day- cooling supily is -available and that design .its ,s- et-y-functi iinto, i theo nt;t e avabilit yte-mperat 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 of--,.movement" .followng an limited and/or the 'temperature of plant intake -water accident or-the occurrence of severenatural phenomena.
-from the sink may eventually become- critical (. -..-cooling -towers, -or --other' sinks -where -2. 'The ultimate'heat-sink complex, -whether composed Srecirculation between 1lant .cooling and ' -.ofsingbeTormultiple water.,-sources, shouldbe intake -can occur), transient analyses -of.supply-and/or withstanding, without loss of sink-, saet functpnof
- " te: emperature should be-performed.
using the folowing:
specified in regulatory
.position C I, the following
--'- " ' --,events'.
-at., A~nalysis sup-porting
'the a,. -vailabi.ity of a 30-day -cool ing. should be: based. oii a. The most severe natural phenomena expected measurements combining the -worst irecorded
30-day takei individually, average) of maxlinumrdifference -between -" dry , temperature and .dewpoint
..temerature,.
AT, -- -b. -The -site-related- events' .(eg:, transportation
-!.and .the..ihest wind speeds recorded during the same accident, river-diversion) historically have ocdutrredý, 2.30-day ~period ýsuch-Ahat the combination of IoT and, orhat may'occurduring the-plant-lifetime, ........... ... ..eas na.ly .. 'able --combinations
'of less, nds,..&. se' r naturalphenomena
2ndfor-site-related events, Mayi "be-madc, 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,--
719I04- For sinks other than-small shallow nooling -3.* The -ultimate iheat .sink.should consist of a least two' --D mnuaransien. .analyses, should.,:be performed to sources of.water,, including-their--retaining st~uctures
1 -ýýde ion d/ortm'imor, ' "u mrnintakewater.
-,eacl-,w th the',cp~abiity -to perform the safety fn ct-ions -'spcfe-i reuator~yposition- C.-l. above, rýitcT-I. -' -p,. ---~ I- -'----------------------
31 -
DC GcmtM 0 Sta ed that thicm is an extremcly
'low 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 u.nts, unless. it cqan be demonstrated that 'Ihere ..is an c~treme~ly'ow probabilityvthat'a ,singleaqueduct can faIil entirelv-'ýs a'T6 Wi of natra peioea.1,Iwae sorces and their Lassuyciated aqueductSs hiouldb b-highfly diaie ndsholdbc separ-ated and pro tected~such'
that failure of any one1will not inducefaihiueof.t
4. The technical.:specifjica;tiofs include ,provisions for actions :to:th
a. conditions
4hrea~ten:
pýt i~dgil Ibe- Wi-niate, heat..sink or -IllieIsatisfy reg ulat ory. posit ions i:C..f-operation.'
~';' p'..-. ~ A, i,%5 * : I I': -'?i!