ML20063L380
| ML20063L380 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/25/1994 |
| From: | SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML20063L373 | List: |
| References | |
| NUDOCS 9403040313 | |
| Download: ML20063L380 (5) | |
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ENCLOSURE 2 Proposed Bases Units 2 & 3 5
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-i 9403040313 940225
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PLANT SYSTEMS BASES 3/4.7.1.2 AUXILIARY FEEDWATER SYSTEM
-The-OPERABILITY cf the auxiliary feedwater system en',ures that-the Reaetor Coolant-System can be cooled down to le';; than-M0 F from narmal operet4eg-eendition'; in the-event-of-a-tete -4ess-of-eff ';ite pcwcr.
In add +t4en 4he-f4ew-paths are automatical1y aligned tc suppeet-en-Emergeney r
feedwatee-Aeteat-ien-Signal-er a Main Steam--Iselation-54 aab 9
Each electWe-de4ven-euxiliary feedwater pump is capable of delivering-e tetel-feedwater-f4ew-ef-700 gpm at a pres' ure of 1170 p';ig to the entrance of the-eteam-9enerators. ThMteam-de4ven-auxiliary feedwater pump i'; capable of demenng-e-tete 4-feedwater flow-ef-700 gpm at a pressure of 1170 psig to the entrance of the steam geneeaters. Thi'; capacity i'; ';ufficient tc cnsure that
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adequate fecdwater flow i';' available to remove decay heat and reduce the Reaetor Coolant System temperature to le';; than 350*F vhen the-shutdown cooling 1
system may be placed into operation.
The ~0PERABILITY of the? Auxiliary? Feedwater ~(AFW)1 System ensure's that the' Reactor Coolant System (RCS)Tcan be' cooled.down tolthe temperature:andLpressure which allows the1 Shutdown lCoolingi:(SDC) System to' belplaced:in operatio.nito(continue
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RCS cooling _.to-cold shutdown conditions.1Thet AFWisystem is:: designed 1to" accomplish this function from: full l power operating conditions 7consideringia totaliloss of offsite poweri ;In!additionc the-flow)pathsifor thej AFW systemiarb automatically aligned to support an. EmergencyjFeedWater Actuation Signahor, a MaintSteam IsolationLSignal EachLAFW: pump andiits associated flow path lisicapable"ofiprovidingfsufficient feedwater to ' stabilize :thef plantifollowing'.a design; basis event,:and to_ remov'e c
decay-heat:atia nominal! rateLequiv'alentf to a 75?F/houricooldown-totshutdown ~
f cooling. : The1 design basis : assumes :th'aticooldown:would commence 130 minutes
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following-reactor trip. :' AFW system flow curves /are used intthegafetyianalysis
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3 for the. spectrum;ofJ accidents 1and eventsidescribed in~ the; Updated Final? Safety' Analysis _ Report. These flow.' curves, whichlcontainfsdfficient margin tojprovide allowance forJsystem modification _siand pump: degradation,:(demo {nstrateLcomplianc withthe'designfrequirements.;Supveillancetestprocedurssl ensure (thatiactual' I
system performance; exceeds these:a'nalysistlimitsi "
i Two' electric? niotoridriven hand Lone;turbineT driven AFW pumps ~ ape; required 1to1be t
operable. This5 configuration can accommodate 1a: feedwaterlline~ break eventiwith single failure loftthe motorfdriven'AFW pump toftheiintact; steam generator. rI_n~
l this case, the turbi.ne driven phmp?is relied:upon for waterisupply;to the:Jintact generator to maintain' decay, heat removal'until;SDC: entry conditionsCare' peached)
Each electric driven auxiliary feedwater pump is powered from an independent 1E power supply, and feeds one steam generator through a set of 4
valves powered from the same lE source. 'The AC-powered valves associated with the same train electric driven auxiliary feedwater pump defines that flow path.
SAN ONOFRE-UNIT 2 8 3/4 7-2 AMENDMENT NO.
' 3/4.7 PLANT SYSTEMS BASES 3/4.7.1.2AbXILIARYFEEDWATERSYSTEM(Continued)
The steam-driven auxiliary feedwater pump can feed each steam generator through two sets of valves powered from 125VDC IE power sources.
Each set of valves aligned to a steam generator from the steam driven auxiliary feedwater pump, are powered from the opposite train from the valves from the corresponding electric driven auxiliary feedwater pump.
For purposes of identifying the appropria+e action statement, the steam-driven auxiliary feedwater pump. flow path is defined as both sets of valves aligned to steam generators.
Loss of Operability of one or more of the DC powered valves constitutes loss of the steam-driven auxiliary feedwater flow path.
If the steam generators are used for decay heat removal in Mode 4 under the provisions of Technical Specifications 3/4.4.1.3, at least one motor-driven auxiliary feedwater pump and associated flow path per steam generator is required to be OPERABLE to provide decay heat removal.
3/4.7.1.3 CONDENSATE STORAGE TANKS The OPERABILITY of the condensate storage tank T-121 with the minimum water volume ensures that sufficient water is available to maintain the RCS at HOT STANDBY conditions for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> followed by cooldown.to shutdown cooling initiation, with steam discharge to atmosphere with concurrent loss of offsite power and most limiting single failure. The OPERABILITY of condensate storage tank T-120 in conjunction with tank T-121 ensures that sufficient water is available to maintain the RCS at HOT STANDBY conditions 'for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> including cooldown to shutdown cooling initiation, with steam discharge to_ atmosphere with concurrent loss of offsite power and most limiting single failure. The contained water volume limits are specified relative to the highest auxiliary feedwater pump suction inlet in the tank for T-121, and to the T-121 cross connect siphon inlet for T-120. (Water volume below these datum levels is not considered recoverable for purposes of this specification.) Vortexing, internal structure, and instrument error are considered in determining the tank levels corresponding i
to the specified water volume limits.
Prior to achieving 100% RATED THERMAL POWER, Figure 3.7-1 is used to determine the minimum required water volume for T-121 for the maximum power level (hence maximum decay heat) achieved.
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i SAN ON0FRE-UNIT 2 B 3/4 7-2a AMENDMENT NO.
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1 PLANT SYSTEMS BASES 3/4.7.1.2 AUXILIARY FEEDWATER SYSTEM
-The OPERAM14TY of the auxiliary feedwater system ensure; that the Reactor Whnt System can-be cccled down to less than 350*F from normal operat4eg tennt4en :n-the event of-a total loss of offsite power In addi44cn, the flow pates-are-automatically aligned to support an Emergeney Feedwater Actuation M9aal or Main Steam 1;clatica Signal-Each electric driven auxiliary feedwater pump is capable of delivering a total feedwater flov; cf 700 gpm at a pressuec cf 1170 ps49 to the entrance of the+tcam generators. The steam driven auxiliary feedwater pump i; c-apable of delivering a total feedwater flew of 700 gpm at a pressure of 1170 psig to the entrance of the tcam generators. This capaeity i; sufficient to casure that adequate feedwater ficw is available to remove decay heat and reduce the Reactor b lant System temperatere to less than 350+F shen the shutdown cooling system may-be placed into Operation.
The OPERABILITY:~ of-the5 Auxiliary; Feedwateri(AFW)2 System:^ ensures 1thatl the': Reactor CoolantTSystem.(RCS)2 can :be' cooled:down1to? ths:: temperature;: Land-; pressure.whichl allows the Shutdown Cool.ingA(SOC) SystemLto'be3placed i.nfoperation::-to' continue RCSLcoolingLto'coldishutdownconditions;;The?AFWsystemLis) design _e_dcto accomplish thisifunctionifrom~ full'powerfoperating; conditions 2consideringis totaliloss4 of offsite. power.. In: addition, the. flow l paths:;forlthe? AFW : system are automatically; aligned:totsupportfan EmergencyJFeedwater?: Actuation; Signa 11or a Main Steam Isolation; Signal 3 Each:AFW' pump?and1:1t'sfassoblatedl:' flow pathfis'capabisfof'proVidingis'uffi'cisnt decay heat at 'a nominal;.he{ plant: followingca de~ sign;basisf eventgandito' remove feedw'ater tofstabilize t rateLequivalent;to a 75*F/houricooldown!tojshutd6wn cooling. LThefdesignibasiscas sumes!: that :: cooldown; wouldi commenc'e s30? mi nutes ~
following 4 reactor trip _ --AFW; systemE flow 'curvestare7used Lin:1thefsafetifanalysis forL the ispectrumlof:' accidents': and events ; described inithei Updated 11~inal$ Safety '
r hichfcontainisufficientsmargin?to;; provide Analysis Report. These; flow; curves w
allowance forfsystem mo'dificationsland'pumpfdegradationrdemonstratel.co.mpliance with the design requirements. LSurveillance testiprocedur'.es:' ensure that. actual
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system performance:exceedsL.thesefanalysis limits. ~
Two t el ec t ri c motor d ri ven !and ton e j tu rbi ne d ri venTAFWfpumps L are Yequi reL to l be operable. :: Thisiconfigurationican':Laccommodatei a' feedwater 'l inelbreakl eventisi th 810" single,failurel:ofthemotor1 driven;AFW;pumpitolthefintactfsteamjgenerator) intact this' case, the turbineidriven' pump isLrelied?uponTforywaterssupply)to; thel generatorsto maintain' decay heat removal untilLSDC. entry;conditionsTarel reached.
Each electric driven auxiliary feedwater pump is powered from an independent lE power supply, and feeds one steam generator through a set of valves powered from the same 1E source.
The AC-powered valves associated with he same train electric driven auxiliary feedwater pump defines that flow path.
SAN ON0FRE-UNIT 3 B 3/4 7-2 AMENDMENT NO.
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i PLANT SYSTEMS SASES 3/4.7.1.2 AUXILIARY FEEDWATER SYSTEM (Continued)
The steam-driven auxiliary feedwater pump can feed each steam generator through two sets of valves powered from 125VDC IE power' sources.
Each set of valves aligned to a steam generator from the steam driven auxiliary feedwater pump, are i
powered from the opposite train from the valves from the corresponding electric driven auxiliary feedwater pump.
For purposes of identifying the appropriate action statement, the steam-driven auxiliary feedwater pump flow path is defined as both sets of valves aligned to steam generators.
Loss of Operability of one or more of the DC powered valves constitutes loss of the steam-driven auxiliary feedwater flow path.
If the steam generators are used for decay heat removal in Mode 4 under the provisions of Technical Specifications 3/4.4.1.3, at least one motor-driven auxiliary feedwater pump and associated flow path per steam generator is i
required to be OPERABLE to provide decay heat removal.
3/4.7.1.3 CONDENSATE STORAGE TANKS The OPERABILITY of the condensate storage tank T-121 with the minimum water volume ensures that sufficient water is available to maintain the RCS at i
HOT STANDBY conditions for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> followed by cooldown to shutdown cooling initiation, with steam discharge to atmosphere with concurrent loss of offsite power and most limiting single failure.
The OPERABILITY of condensate storage tank T-120 in conjunction with tank T-121 ensures that sufficient water is available to maintain the RCS at HOT STANDBY conditions fer 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> including cooldown to shutdown cooling initiation, with steam discharge to atmosphere with concurrent loss of offsite power and most limiting single failure.
The l
contained water volume limits are specified relative to the highest auxiliary feedwater pump suction inlet in the tank for T-121, and to the T-121 cross connect siphon inlet for T-120. (Water volume below these -datum levels is not -
considered recoverable for purposes of this specification.)
Vortexing, internal structure and instrument error are considered in determining the tank levels corresponding to the specified water volume limits.
Prior to achieving 100% RATED THERMAL POWER, Figure 3.7-1 is used to f
determine the minimum required water volume for T-121-for the maximum power i
level (hence maximum decay heat) achieved.
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SAN ON0FRE-UNIT 3 8 3/4 7-2a AMENDMENT NO.
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