ML20024C420

Description of Reactor Vessel & Closure

ML20024C420
Person / Time
Site:	Crane
Issue date:	07/11/1983
From:	BABCOCK & WILCOX CO.
To:
References
TASK-06, TASK-6, TASK-GB GPU-2347, NUDOCS 8307120611
Download: ML20024C420 (49)

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SYSTCf CPTP,AT*C4 1.

Funda=estat oserat*ons_

De fo11 ewing subsee:1cas will describe the fand= ental operations The reader will note that many centrol functions a:s of the M54 For examples povided by interface sys:c s (see Figuee RCS-21).

p the Secondary Systes re==ves ' heat f:ss the RCS as a =eans of a) l contro11:=; the M 5 te=perature b) The M.deup Sys:es adds and re= oves Keactor Coolant as a mes:s l

of con::alling the Es wa:e inve::ory.

1.1 F er cost-o1 n e pews: output of the rea: or co61ss: systes is dependen: ~on the The energy released nu=her of nu: lear fissic.s in the rea::ct enre.

by nuclear fissicas =s. ifests itself in the for= of heat which is tisasferred to de reactor coolast then to the Seccadary Systes.

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Approxi=stely 80% of the '.ission energy originally appears as kinetic.

a Mas: of the remaining 20% appests energy of the fission fr:g=ents.the excited fission f sgue=ts and as kinetic as 8 and Y radistics f c:

energy of the fissies neu : ens.

The neutron fissien rate is controlled with control rod asse=blies.

axial power shaping red asse=blies a:d soluble boric acid.

The cost o1 Tod drive =echanis:s (CMM) =ove the control red asse:blies Ths.cen:rol r:d asser.blies and axial power shaping red asse=blies.

control rela:ively fas: reactivity effects such as the " power defect".

The axial' power shaping rods centrol senen osci!!a: ions.

The soluble boric acid is used to ec=pensate for slov res:.ivity effe::s such as fuel depletica, "teepera:ure defect", and axenen and sas riu="

,oisonin,.

Power cent o1 :y be ex hanged between the c. :o1 od asss=hiles and the snichle beric acid censistent vita "-4:sticas on ;cver pealist.

.the reae:c: ;;ver can be reduced by inse: in: c::::al.

For ex=ple:

zods, then the :ds can he sicwly withd: vn as beric acid is addsd to the reactor coolast.

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1.1 Teeperature control-(

' The reactor coolant ta=perature is controlled by balancing heat laput and re= oval. Severd acehods of heat inpuc and

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removal are esplayed.

Meat loput to the RCS is provided by the core decay heat, l

nuclear heat..and t,he RC pumpe.

The secondary system and decay heat removal systems are used for heat renoval.

1.2.1 Deesy seat When fission products are formed, they contain too many neutrons to be stable. Thus they decay with ar.ission of radiation - in particular $ and T radiation.

During p=ver op.e:ation, this radiation centribu:es is the recoverable energy since the bulk of this radiation doesn't es:spe from the In addition, since the decay of fission pr: ducts c:n-inues core.

after the reactor is shutdown it provides a continuing scurce of 1

heat.

1 During power operation, the a=omt of decay heat available vill deper.d on the power level and length of ti e at the power level.

After the reac c: is shu: deva, the a=omt of decay hea will depend

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i also an the length of ti== since shu:dcrn.

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g 1.2.2 Reactor C:stsat pt..._s Heat

3.,I Heat input f c= the RC pumps is 7:wvided whenever the pu=ps are tl operating. The heat is generated by pt. p work. The acom of heat input to de coolant will decrease as the coolant de..sity de:::ases.

The pt=p heat input can be varied only by va:ying the der of i

l operating pu=ps.

Pu=p heat is the major source 'of heat addition duri=g heat up of 3

the ACS to hot,:ero power. Even duria; ;ower ope s: ion the pu=ps add a significant a=omt of heat.

J 1.2.3 Hesttro at tev Cectant Te= erstu es The res= tor ccolant pu=ps cannot be operated below certain Ab pres.

sures due to the NPSH require =ests. 'D.orefore, the RCS pressure aust be increased to provide the required NPSH prio: to s.artir-g

,a reactor ecolant pu=p.

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1.2.4 Nuclear Resc 3, u..

h Nuclear heat *.s produced by nuclear fission. his heat source is (3. g used to increase the RC te=perature be: vees hot :ero power and 100:

yF De heat inpur is increased by increasing the nu=her of pever.

nuclear fissions by withdrawing control rods or remosing boron from

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- I(I the reactor coolant.

o Duclear heat provides the majority of the heat during power operation.

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1.2.5 Secondarv System

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ne reactor coolant sys:es is dependent es the secondary systes for

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tj beat re= oval between ICC* Power operation and a reactor coolant I

i temperature of approximately 250 F.

If the condesser is noe available

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to receive the steam generated is the steam geserators for removing 3CS heat, the steam can be vented to the at=osphere.

j Decav Mest Re=ovat Systes_

De decay heat removal system is used to remove decay heat den the i

thermal driving head of the reactor coolast systen is no longer

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adeguate to ge=arate steam in the Secondary System.

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j 1.3 Fressure centro 1'

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ne RCS pressure is cont s. led And maintained by the pressurizer asse=bly.

l his assembly has a power operated relief valve and a spray system for

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[kl reducing pressure ' and electric imersion heaters for increasing pressure.

In addition, the pressuriser is desig:ed with an inherent pressure

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1.3.1 Pnssu e Se -nssion_N is connected to the rese:c cro12nt 7 71:c 1

he pessurize; vessel The vessel,is partially filled with water at saturs:ics, by a surge pipe.

i tempe:sture so tha: theie=ainder of the space is illled with steam.

ne vessel acts as a surge cha=her whi:h acc===edates chs=:es in reac.or cocisa: volu e resulting f== a change in coolant de:81:7 I

During c olant outseles f:= the pess=i::: vessel the syste= ;;ess=e decreases and sc=e of :.he water in the pessur::e; flashes to stsas and limits the pressure decrease.

Durin's cec 13=: insurges, the increasing stea= pessure c=ses so=e of the steam to c= dense and li=it the pessu:e increase.

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he 3 Fay systac: psvides a relatively cool water s;:ny 1:to the vessel steam space wht:h cs.de.ses sc=.e. of the stess to reduce pessure.

The pressure diffennte he:veen the RC y=p disb.ar,.ge and the pes =

cvides the drivi 3 fc=e whi

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:uses some rese =r cool:nt to flov Babcock &Wilecx f:ca the RC pspe to the pessuri:e:.

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fi De spray flow is controlled' by an ele:::ic =ctor operated (DC) g1che L.

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Den in =snual a jog chi:

De valve has nr.ua.1 and auto control.is provided so that :he f1 q.

}f rate of depressuri:s:ica.

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Wen in auto control, ce valve vill op n at a high pressure set pois:

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t ec low and.aintain the vr.1ve open until tha pressure is reduced to a f!,9 i

ij pressure set Tsint.

only to a predeteruined i-The su o open signr.1 vill open the valve, bu:

The valve always b opening to 11ait the ra e of pressure redu: icn.can be opene is j/T fi desired.

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nited percent cpenins Provides a flew r

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arp lead chsagts. ye: provides a flev limisstien to prevent an J

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l excessive rate of pressure decrease in the even

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failed open.

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If the sp;ay valve failed open, an isolation valve in the spray line This valve l

can be closed to prevent an excessive pressure decrease.

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has only remote manual control and must mak.a full open and close

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If' o h of the RC pu=ps in the RC loop with the spray f i' p

the pressuri: : nay be insufficient to ;;cvide a spiny flow.

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Du:Ing the seccad sta:e of cooldown, i.e., after the RC peps have 27 ficW L

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been shut!.:nm and the Cec:y Hea:will be supplied by the Decay Heat Syste i

. tine which cor.nects to' the pressuri:e sprzy l ne.

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In order to use the auxiliary sp sy flow ce sp;=y valve d

toward the pressuri:e and not toward the RC inle: pipe.

The suailia:y spesy flow supplied by se decay heat sys: = is used during CH systen operation since ce RC y=ps are not operating at W

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l 1.3.4 Power coersted Relief valve.

j The power operated relief valve reduces pressure by opening and relieving steam from the pressurizer vessel.

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De valve has manual and auto control.

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The manual open signal vill open the valve at say desired pressure.

f' y Nu the switch is returned to th's auto position, the valve vill r

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, close if the pressure is below the auto open setpo h auto control viu open the valve at a high pressure setpoint and keep the valve open until the pressure is reduced.to a lov

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• Pressure setpoint.

The power operated relief valve is designed to prevent excessive i

Like the spray challenges to the pressurizar code safety valves.

valve, the pouer operated relief valve is provided with an isolation

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This valve has nanual, fun open and close control functions.

valve.

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1.3.5 Westers The pressurizer heater elenents electrically heat the water in tha (l

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ne heater elenents ll{i Pressurizer vessel to increase the pressure, are grouped into 5 banks of heaters. They have manual and auto f

control.

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'When in auto, a bank viu energime'at a low pressure setpoint and r-re=ain energsted untu the pressure is increased to a high pressure 4

12 The low pressure setpoints are such that each heater b-setpoint.

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bank will be energized at a different setpoint as the pressure

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'f Bank fl. 2 and 3 operates at and slightly below the tornal operating 3ank #1, 2 a=d 3 are con-

.h pressure and has a variable heat output.

-g trolled by a Pressure Indicator Controner which has an output pro-

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The Pressure Indicator Controller

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portional to syst'en pressure. controls a Silicon Control Rectifier Controner which varies j

I Therefore as the pressurizer lI, heat output of the heater bank.

Pressure decreases, the heater back heat output increases until at about 25 psi below nor=al operating pressure, the heaters are at

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fuen capacity.-

i When in manual, the Pressure Indicator controner is manually varied; whne in auto, the Pressure ladicator Controner receives input from

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the narrow range pressure instrumentation.

The total heater espacity is designed to allav an average 50*T/Er hestup rate with a normal pressuri:er vater level.

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Low Level incerlock_

low-level 1 3.6 The pressuriser heaters are protected by a pressurizerT i

r the heaters from being energized if they a e l is below approxi-S interlock.

The interlock is initiated when the water leve e

antaly 6 inches above the top heater.

i 5_etootut stenals r operated 1.3.7 The ' signals for auto operation of the spray valve, powe pressure

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relief valve and heaters co=e from the narrow range,,

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1.3.8 Sprav Svstes_

i To depressurizer the RCS during cocidown operat ons,

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f To limit pressure increase during load change s.

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s To limit pressure increases during step load decrease.

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To counteract slov. pressure decay resulting from pres-3 suriser heat losses during steady state operation.

l ing To restore pressure to normal operating ~value fol ev

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load change transients.To pressu:izer the RCS during heatop o

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Reactor cocisa flow is maintained either by forced pu=p flev a 1.4 b,.

I natu=al circular, ion.

is varied since the RC pu=ps are constant speed, the forced flowrate can caly by changing the n==ber of pt_-.ps stich are operating.

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During natural circula:ima the flew can be varied by c'..ang ng 1

of heat re=cral.

is achieved Contrel of flew distribution through the reactor vessel by arrangensat and design of the core inte==als.

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Flow Co=:re! *'hrouch Reseter 7

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la the reactor vessel, ce internals have a major role in' directing coolant flow. ifos: of de flow is directed down along the core strpport shield then up through i flow distributor head whl=h eve.ly distributes the now into the c=re. After passing th ough the core, the coolan:

is direc.ed i:p a:ound.he control red guide :thes and then out of the vessel.

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Although =est of the reac:c; coolas: flow is dire =:ed through the core, ePProxi=stely.n (= x.) of.he total flow is dire::ed up be: ween the core suppe:: shield and the core basket. This flew allevs =ixing cf I

the va:er in this area and helps to re=ove gar..a ine.::ed heat fica the reactor in:::.als.

In addition, the flow eli=inates any pocketing of i

non.condensible gases.

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The remainder of ce flow which by-passes the core has the following flow pa.hs:

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a. m Approxime ely 2.0% (==z.T of :=.al' flow leaks around the i

j conne=: ion be:veen the ou-le: =c::les and the core support f

asse=bly.

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Apprezi=auly 1.M (=ax.') of the to:a1 flow passes creugh da incere inst:.=:catatica sad control rod d.-ive

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This bypass flow provides coolant flow to the area tader the

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closure head..Nex: this flow passes through holes in the Plenum cover to the resc or outle: no:..le, s

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Reverse flow vill o::ur through idle res::or coolan: pu=ps whenever one or ec:a :eactor coolan M s are operating.

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When one pu=p is idle, only the flow through that inle: pipe is Teversed. Bu: if both Ms of one loop are idle the flow through l

the whole locp is reversed.

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1.4.3 RC h==o Coas:down 71ow' I

Iach pu=p has a f1 wheel so tha: if all RC pt ps lose drive power

-3 sufficier.:===en:== ~will be available to per= : the flow to " coast.

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down", thus providing a tr=.nsition frem forced circuis: ion to natural circulation and preventing the D.N3R from ex eeding design li=its.

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1.4.4 Natu at circulation g'

The natural cirr=la:ics flow rate will depend on the a=ount of decay

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F heat l' the core and the ra:e of heat re= oval by the stes= generstars.

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After shutdown fr:s power operation,' the c re prod==es enougn decsy j-( t.

. hest so ths: sufficient natural,circula: ion is preda:ed if the s:::=

g 3enerators remove only enough hes: to keep the K:3 te=perature c=nstant.

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However, with a new core (no de'esy hen:), the RCS should be cooled r

1, at s200F/hr by :he steam generators in c; der to =sintain sufficien:

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natural cir:ulstion.

he na =ral ciren12:ica is sufficient l

to prevent cold seal injectica water frem accu =lating in the cold

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In addition, a con:inueus natural cir:nistion flow should be main-tained to assure a p:cper tube to shell lll in the steam genera: ors.

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4 1.4.5 Eiz ole 0:eratine M ::lons

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During cocidon,n, one RC pu=p in es:h loce_ is no:= ally used to a..

pu=p coolas: thrcugh the steam genera: ors.

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When ven ing 'the K:S, he pu=ps are each operated to renove

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non-condensible gases f the loops.

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i water Invente:v Centrol.

1.5 The RCS vate; invents:y is ce=: rolled by balan:ing water ad h,

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pu:p sca'l injectica of the ysheup and N ificati=a Syste=.

and remval.

t and by is removed via the 1e:down line a the 111 and P Syste=

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RCS leakage.

j The pressuri:e; level is used as an indication of the RCS va s.

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p taining the pressuri e level at a desired level.

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p tiuring ac =al e-e:3:ica ce water re=oved through the 1e:down line 1'

c is is kep: c: stan't while the wate; added th cugh de =akeup line The seal autc=atically varied to ec=pensate for density chan es.

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injection is kept constant.

t Pakeen t.ine 1.5.1 Constant speed =akeup p=ps of de }UIP Syste= drive water thrcugh P

The water flow I

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the =akeup line to the RCS fr== the 301p Sys:e=.

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l The th:cugh the line is :egulated b> a =aleu-ficw control va v i

level within.a specified band throughcut all p.ases of,reacto:

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operation.

The flow control valve is provided with =an=al and auta=atic c=ntrol.

While in :.anual centrol, ce =akeup valve ay be re=

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makeup flowrate.

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In au c=a:ic c=:rel, the valve vill cperate to =si= sin a Fesstiri:e c:n be =anur.11y var.ed on the = sin h

level set point. The se: poin:

Any level dev.atica f := the se*

control canal to a desired level.

point will be au:c=ati::lly c::: ::ed by adjus:=en of the =akeup

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flow :ste with the =akeup control valve.

The signal to de controlier en ce =akeup val've which positicas the valve ce=es f:c= the pessuriser level inst:.=:estatica. -

i level to p,

Small variations in RCS te=pers:=e cause the pressurizelevel ch=ge is dep F.

-l change; the a=cun: cf pressuri:eLead ch=:es i=pesed upon the reacts:

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coolant systeh will cause these te=perat=e vart.atio=s and will cause sr: cunt of te=eerature ca nge.

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action of the =akeup valve.

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In addi:Icn to the water added th.cu:h the =akeup line, water is added by the RC p=p seal injectisn. his f1w is set to see:

b he varied Ioad de= ands c'f the RC pt=ps, and :nerefare, canno:

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Hewever, the total water added by 1

to control the wa:er inventery.

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the seal infection is a major portion of the =akeup va: : added to

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the RCS.

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I 1.5.3 f.etdow F!ce 4

The letdown line of the MJ3P Syste=.is used for remos-ing the reacter.*

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The driving for:e is the higher pressure of the reactor coolan:

I, coolant. Cu: side the reae:c: building. the 1e:down line has a reso:eThis valve is no rys t'e=.

manually cperated flow con:rol valve.This valve also allows for very large to maintain a c:nst:st flovra:e.

flowrates su:h as d=ing hestup when the reactc; coolant is expanding and for ve:y s=all flow rates su:h as during cooldoen.

I 1.5.4 R:' h=s Con: olled 11eedef' The centro 11ed bleedeff lines re: eve the water which is staged thrcugh This flow rate is genera.11y c=ns:snt. E:vever, i

the RC p=p seals.

.i it will va,y wi h seal injection pressure and the conditica of the RC i

This controlled bleedsff is a'ssail portica of the seal l

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injection flew.

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1.6 Che=ist-v Centre 1_

'The reac:c: coolan: water che=istry is main.alned within certain 11=its to mini =ize t:. desirable che. ical reac. ions be:veen the =etallic eca-

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ponen.s in the. reactor coolant system and the reac:or coolant.

7 In additica, radioactive conhtituents of the reactor ecolast are continually rs=cved.

The reactor ecolant chemist:y is =eni:cred h taking sa=ples.A sampling line f== the 1e de.7s line of the Makeity and Purifica:Icn System provides sa=ples of the reac:c coolant system.

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The pressuri:er has two sa=ple lines, ene for the steam phase and one fer the wa er phase. The sa=ple' line fre= the stea= space per=it:

It also detection of nen.conde sible gases in the stean s, ace.

provides a method of re=oving non-condensible gases.

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d.d chemistry of ce pessuri:e v..ter will not vary cen ::i:antly with j'*

the Ts=ainder o' the rese:or coolant due to de semi-s:a:ic cenditica j

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Vja Contro'1 of the R:5 che=istry is provided by de Che=ical Addition t

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The rese:o coolant

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1stdown water is : ea:ed in de Makeup and Furificati:n Systen pio

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to being restored to the R S and chen:cals are added to n.e RCS f:ca

-R the Chenical Addi' tion Systes v,ia the Makeup and Purification Sys:sa.

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• De chemist:y control is mostly cone'erned with controlling oxygen e

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pH, ci and 7' and dissolved solids.

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instances as described below.

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Ih :ing RCS cooldown when the possuri:e pessure reaches }ppo-J.

is added to the pressuri:e through ne vent ximately 50 psig. N:

The N. Will =aintain an ove presa=e while the possuri:e j,;g

' nozzle.

is cooled by t5e auxilia:y sp;sy. The ove pessure is required q

'to keep the high point of each RC ou.let pipe in a solid,wa:e

!g

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een'.L: ion.

NOTE: The 50 psig value is a censervative value. The actual pessure squired will depend on ce water ta=perature in the RC pipe il and the pessuri ar level.

3 4

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i 2.

When draining the reactor ceolant systa=. N; is added to each

'j The 4

RC loop and the press = :e: at a:=osphe:ic pess=e.

reactor coolant is drained fe; the following situssions:

.]

A.

for reactor closure head removal 3.

for reacter closure head replacanes:

C.' for maintenance such as RC pt p re= oval, steam generator tube repair and core flood che:k valve : pai;.

This nitterer. cover gas povides p:::ection' fro = corrosica.

3.

Nhen the rea or teol:n: sys:s= is bel =g filled, ce pressuri:::

vent is closed causing the nitrogen in the pessu::: : to be compressed and ic :e :ne fill us: = up into the R ou.le pipes.

When the wate level in the pressuri::: reaches a pedeter i..ed j

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.d 1evel, the filling is s =pped and 30 to 50 psig of nitrogen is H.

added to the pressurizer. This will force the wa e down in d

the pressuri:e; and up to the' top of the ho: les pipes. At coupletion, -he p:essuri:e; wa:er level should be below the jj O.

normal operating level and above the hester low level interlock

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level. This prephres the RCS for fo=ing the pressuri:e; steam j

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kubble,

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, g-i Escess hydrogen is malatained in the na: tor coolant tu mini =1:e I *!

oxygen cor:cs'ica by co=hin:ng f;se oxygen resulting from radiolytic l

I :{

dissociation of (water) selecules, I

t The hyd: ogen is added to the rese:oi coolant by =sintaining a hydr gen

,Il overpressure in the sake up tank of the WT.? system.

Degasification during power operation is done to re=ove fission product gases and other undesirable non.condensible gases ".~ the 6

' t d

pressuri:e: steas space and the reactor coolant.

.-1 i, t Degasifi a: ion'~to a reduced hydrogen concent:stion f=

RCS shutdown where the RCS is to be opened is desirabic in order to preven:

explosive hs:ards due to evolu. ion of hydrogen and radiological ha:a:ds due to the release of radioac.ive gases."

the coolan i

into the vactor bsilding.

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DegasifiC3:1Cn should be dOne prior to CooldoWR to take advantage of.

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,,,the diluting affect caused by adding gas free aske up during cooldown

' for water c=::2:: ion. However, degasifiestica can be done con-4 currently with cooldown.,.

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The hydrogen con =ent:stien should be redu=ed to.,...zinately 7 std.

ec/kg prio; to renoving the resetor vessel closure head. This will prevent the possibility of r.n explosive =ixture fo =ing ur. der the reactor clesure head.

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Open p;ess.:;i:e; gas ss=ple line to letdown 11st

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the. le:do ;. !!cw to the degasifie; f'

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,e,ase ee.am.-. <- =a:e -.._v-x hr4=:e= ~=-

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p; essure to assure sufficien: hydrogen addition to :ne =akeup n'I{'

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che=ist;y ; qu.;e=en-s.

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- water to caintain the reactor coolas:

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With no degasifie; the RCS H; concentra:lon is educed by l

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lowe;ing :he esieup tank H2 E

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Using W tank vent.

in the coolant to the P;ior to the cocido.n. redute the H lower end of the 25-:0 c:/Xg spe:ifin-ica range by adjus-1' the Hg partial pressu;e in de }"J tank to de ; equi;e=en.s to maintain d e lower H2 88"::" 72:10" 1* D* ** 1**t*

t According to Henry's law, sa H: par:ial pressu;e o.,:13.., psis t

However - Vill t

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(.1 psig) cc:;esponds to 15 c:/Eg water. partial pressure probably be necessa:y to use a higher H:

,I

'l in the W :sak to aihtain 13 c:/Kg in the coolant.

Afte; the ezeto; has been placed in has shutdewn ccaditions.

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2.

i.e.. the ::ac o; is suberitical. displace ne H 2

p, _

as follows:

the HJ tank with N2 Cpen p;essu;i:e; gas sample line to le:down line.

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The p;essuri:e; can also be u.111:ed for dezasing the gases in the g7T1:

by using the sp;ay valve to colle :

pressu;L:e; stes= space and den venting ce stessCf cou;se, in using this

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space to de quench tank.

the method, the cperstions =ust be a;-anged so 22:

pressu;i:e; 7; essure is maintained v'cin de f. f e; This can be done by balancin; ce a=ount limits.

of sp;sy flow used with the heating capability of t

i the electric heaters.

g C1cse all gas supply valves to de makeup tank.

b.

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c.. Cpen the =akeup ssk vent.

5 to main *

• 1.init de gas discharge 6;ough de ven:

NerE:

necessa:y tank pressu;e for ce.akeup p NFSH.

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Raise the zakeup tank wate level to push out th's 9{I

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Lower the wate level'. adding M2 (vish the ven: valve

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closed).

l These above operaticas are perfer=ed as =any ti=es as required to e

t if}s reduce the.lg pr:ist possure to about one psia in the >11 tank.

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B.

Degasing with Gas S::ipper I

than using only Degasihg with a gas stripper is sere effician:The :ste of gas rc= oval s-ill dep the >1l tank ven:.

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1stdom flovrate through the gas stripper.

E Perfc = the steps of section A above and in addition, the y

'II 1.

following step.

j Establish a letdown flow path through the prefilter.

.h';t de=inerali:::(s) to the gas stripper and then from the 2.

i gas st:1pper back through the de-anerali:e post filter

{l to the PJ tank. Adjust to a large 1e:down flow rate and maintain this flow rate as long as pasible to,,revide y

for,-~4-"- degasing capability.

.j 1.9 Vedtin* the RCS Durine Sht: dew

,t Du:ing shutdown of the ES, nen-ccadensible ' gases will came out of 4

t These are ha:ardous gases and should be removed before So=e of the gas will be hydrogen which

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,bresching the Es in:egri:y.

The system also l,

was not recoved'd=ing degnsificatier. of the RC5.

contains radi=se:ive gases which would be a hes1 h ha:ard if releassi

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Therefore.

to the resh.o building and delay refueling ope:2:icns.

E

',these gases should be properly vented to the resetor waste system.

1 F The RCS is also vented during system fill and during startup to re dve l ;

~

In additica,- the KS is vented fc11ow".; an occur e=ce 4

l entrained gases.

dich migh: result in gas ent sin =ent.

1

. lollowing is a s-*-y of when the RC5 is vented:

4 Followi=g fill c refill of the RC system.

Followir.g the first 13 mi=utes of RC p=p cperation af:e filling.

s.

Following loss of level indication in the pessuri::: if ni::cgen.

p b.

c.

g was thi ;;essurizing =edi= in the pess=1:cr.

If the RC pessure is below the r.ir.:== peasure rectired to keep d.

dissolved :ses in solution, such as dur n; c after ecoidova.

Following loss of level in either core faced tank if RC p;esaure

'w e.

is below core flood..ank possure.

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f..Following dr:ining and nfill of any piping syste= connected o l

the reactor which has evented high point esc =:.r.ica:ing with the RCS.

j 3

Following 1 css of level in the 1e:doen storage task taless valved off dwing drain and refill.

h.

Prior,to removi=g reac:cr clesce head.

/

1.9.1 Venting the R 3 Ou.rier P!:.n: Shu:d:mi After cooldown with the RCS ta=rpers:=e apprezi=a:ely 1.*0'; and nitrogen overpressure.heing tais:Ained, al? the CK*.2f's, presseizer and steam

. generater an vented t'o the reactor waste sys.es. After this ve=ti=g

+

the RCS is ready to be drained.

j 1.9.2 Ven:8nr the P05 Du-int Ti!! int and P!:.: 5:artus

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I After refuell'ng and during plan: startup, the RCS will have three-I periods of vesting.

he firs: ven.i: vill oc = when filli=g he

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205. The secer.d ve :ing will be =ade after :he ;ress=i:er steas i

bubble is fo=ed and bef:re ce RCS te=pers:=e reaches *12,7.

j De third ves:ing vill occ= when the reac:c coolan: 7,s are in 8

operation.

0 1

Before the final venting the pressuri:er =ust be ver.:ed and the RCS total gas concen::::is: =us: be reduced. :n the te:hr.ical specification

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limit. The pressuri:er cas be vented =encurrently vid heating the pressurizer water to for= the steam bubble. After ce pressurizer stars bubble is fe:=ed and.the reacts coolant systa=,. esstrre becomes sufficies to sup;1y the ret;uired p=p.NPSH, the res= :: coolant 7.=ps can be operated to =ir==.12:e the reactor coolas and eld-4-s:e gas pockets in ten-ve :ible areas. Also when ce pressurizer s.eam bubble is for=ed, the =1::= gen c ver gas is vented frs= the pressuri:er eliminating a soc =s of non.csadensible gas. The pressuri:er ten-i Perature can *oe =saswed conc =ressly with se ven.ing.

[

The RCS is vented before reahr 21:*p 23 prevent flashing i= the vent lines.

Following is a s-- y of when the RCS is vented:

The a.

From the presswi:er vant if in a solid water conditions.

pressuri:er has t w ven: paths. One path is for ve= ting non-l condcasible :ses. The c:her f1r. path cos.sists of a line connecti : to the p essuri:er relief line. This' pa h is used I

for venting s:ea=, since 1: takes adeas age of the s eas quenchi=g capability of the relief line to the 10 drais task.

e-NCTE: De power coerated relief valve cannne he used for venting because it recu.:res a =i.**- t.P across the valve of a= pro.

aimately 50 psid o operate'.

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F:ca the top of each outlet pipe. This is done only during..the first ver.:1:; af:e filling the RC syste=.

j 7:na each centrol drive mechanism. Flexible heses are used for

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venting de control rod d: ves zer.hasism and di ecting the gases'.

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to the waste disposal system.

~

If the rods, when trip;ed, are not vented they will drop with saceptionally fast drop ti=es and the hydrau18e buffering device i

will no: fm etion. This sudden deceleration could be de::imental

'to the cont;o1 :ods.

d.

Froa each incere monitoring tube. 'this is required only during l

first venting af:e: :sfilling.

i

. A p

l 1.9.3 Procedure l

Venting is done while observing vent path pressure and temperature linits, es;ecially these per:aining to.r.e control rod drives.

l-Venting limits are based m avoidi:g stea=i=g in ce vest line under i

atmospheric condi.icas.

5 If ve'.nting is required and the reactor is above the a'llowable 11=its

[

for venting, the ACS is cooled down t=:11 the li=its are met. If

.the RCS is cooled down with two RC pu=ps opera:ing, the other two t,

satst be rm in sequence prio; to vesting. If the ACI is cooled

+

p dow1 by natt al circulatica, all the RC pu=ps (no = ore thas.hree p

at a time) =st be run prior to venting.

I Per further venting during shutdown and. filling, refer to the draining i

f and filling operation descripcions.

w r

L.

pollowing is the procedure for vesting during system heacup.

t b

During system bestup and prior to :ea i a ~,,, of 118, the M is vented as follows:

1.

The RCS pressure is increased to the p sssure required to operate

[

.the RC ptarps.

2.

Operate one RC pu=p s*- 1:aneously is leap A and loop B for i

y app;cxi=stely 15 nir.utes.

l

.During the above 15 mi==:e period, cperate the 3rd and.ith puI:ps 3.

I in sequenes. Note: Wait at least one =isu:e after steppi=g r

the 3rd pt=p before starting the 4 h pump.

d.

Vent each CRma.

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• s 69-t 1.10 Fittine the R:3 The RC3 is filled by 6, WCP system th::v;h a line that bnasses I

the zakeup tank. Durin: fillia:. the hi:h points of the RCS are ve=ted to the Reac.c Sulldin: =:11 a va:er level is indicated is de pressuri:er. At this time, ce pressuri:er ve..: is closed and thea l

water is agais added':n de systa= while es= pressing the nitrogen g

i in,the pressurizer.

t 1.10.1 Procedure L

1.

Prepare )CCP system to fill RC5 f-L

'2'.

Open the center CTI.M vent, the pressuri::: vast and the vent i

in each R:3 he: leg pipe.

3.

Start filling the RCS vith berated va:e and add hydra-ine

.as required.

4.*

Close the center C7Ct. when water issues from it, s

5.

Vent any high points in CH, WCP, and C7 sys:e=s. Also fill and vest 1:str=en lines.

l i

. 6.

Close de presswi er vent when water level is indicated is pressuri:er.

8 l

a 7.

Continue filling until the' pressuri:er water level reaches jL

~

the specified level. At this.ise N is added to the j

h, pressuri:er until va:ar issues from the vents in the ho: leg i

s pipes. Then close the has leg ' ipe ver.:s.

i 1.11 Drainin; the P 3 7

The RCS must be partially drained for various inspections, main.

-1[

tenance and repairs. The compone=:s a:d water volme to be drained will depend on wha: vill be done. Following is a list of ite=s which

..h, require draining cf the RC3.

, g i

A.

Refueling 3.

CRD! Re=cval C.-

RC Pu=p Re= oval D..

Pressuri::: Relief Yalve Removal i'

E.

CTSC h be Repair

~

F.

Pressuri::: Hester Removal C.

RC Terper ture De:ce : Re.-oval (non-well type)

H.

Core Flood Check Valve Repair 1.

Some Inse:vice Inspection P

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P I

Babcock & Wilcox.

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ne entire p.c3 c:n be drained ex:ept fc the por:iza of the reac or

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vessel belev the veactor inle: pipe no::les. nis water a:.:st re= sin f

for radistica shielding and care cooling.

t 1.11.1 Initiat C Editie.s

/

Before drai.1 g, the RC3 =ust be in a cold shutdown condition and

{.

bo hted to d e requi.ed shu.do.:.oncent:stion.

.s 2n' addition, the R:r pressure and te=pera:== :.ast be 7,duced to sonditions ac:eptable to the vaste disposal systen and de vaste l,

disposal systa= :us be p;c;ared to accep: tae volu=e of water to

,be drainee.

g ;

I 1.11.2 RCS Draining I

l 3efore d sir.ing the RC3.1: =ust be vented of radioactive gases ll and the press =e =ust be reduced to ce reactor building (RS) g f

P essure.

i De RCS is drained by opening de drai.u on the reactor i=les pi;es.

However, additiona' draining =ight be required using the press = :::

l surge line and CTSC drains. As.he coolan: is drained. N: is supplied r

th:c:gh esch reactor cutle: pipe vent and the ;;ess=i::: vent a facilitate draining. Nitrogen is used to inhibit c=: esir.n. De f-nitrogen press== is =sistained at s reac:c; building pressure.

Each R cu.1e: pipe vent has a p;cvision fer connecting a pressure r

or level indicate for guidance.

. E After wate level reaches % the top of the RC p=p casing, open vents

.r en the seal injection line to pre:1ude ce for=a: ion of a vac=:.:::

,p

.in th.e. puzy casing d=ing draining.

P 1.11.3 Addittena! D-sir.ier na R:s drains ;;cvide draining of the entire RCS except for ce t

following areas:

y l

a.

De sectien of reactor coolant inlet pipe f ca the RC pu=p to I

the reae c: vessel.

b. ne section of reactor coolant au.let pipe f:=n the reactar l

vessel to an elevation ecuiva. lent to ce RC p.=:p bew1.

De reactor vessel below he elevation of the RC pu=p bowl.

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L E

Making a,terport:y d sin c=nne::ica to te low p; essure tap

CTZ: 21s is ce pressure a.

on the cac::: :: alan: ou le: pipe.

T tap us'ed for level indication.

/

By opening the DH Systen drais.By directing sc== CH System flow to de b.

r s.,

opening the surge line desin.

t only partial _ drainin; cf de above areas is ever required and his is wa:e: fr:s rieshing i=:n the RC pu=p bwl by DH Systaa I

'to preven:

surges when perfo:=i=g the following operations:

I Removing a RC Pt=ry a.

b.

Plugging (TISC W oes Repairing Core Flood Check Valvsa.

, c.

i Draining this area is restricted by hPSH res: ire:ents of the DHHowever, these pu=ps and vertex fe:=ation in the DH suction no::le.

require =ents will vary with the required DH flow. '

I I

1.11.4 Level Menitoring h

When d.m*** g the RCS, pressure indica:s:s. are attached which meas.rreIndicators are locate static wa:e: head and provide level indication.d::in and one is Icetted on the rea: or T

on each reac.o cuolast inle:

a coolant inle: pipe.

Additional level indica: ion is y:m-ided by the pe==anent pressuri:e 1evel inst:.=:entation.

t

." 1.11.5 Precedu=e_

A.-

Initial Cenditions_

1.

RC5 in cold shu: dews 2.

OTSG in we: or dry layup en secondary side

[

Waste disposal syste= prepared 3.

4.

, Level indication available t

r-B.

Vent RCS-b Ven: CL"M to 'gasecus waste ven header 1.

Isolate gaseous waste ven: header fr:: res:.s wasts systes i

2.

Ven pressur :er.sg cever gas to ven: header

.l 3.

4.

Vent RCS hot leg to vent header r-f I

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Drain Syste= (Pa-: Il l

Part.! is sufficient for delag the following:

i f

a.

CR2f Removal

^

b.

• Refueling c.

Press = i::: relief valve repair

• d.

RC ta=pers:=e detec.or removal (non-well type) s.

RC Pu=p Ra= oval.

2 to reactor crola=t ou.let pipe vents and i

1.-

Supply N pressurizer vent.

2.

Open RC inlet pipe demias. Continue to add N2 at reactor building pressure 3.

Stop,draini=g nea water levei rese5. :s desired level.

D.

Drain syste.= (Part II)

Part ! 4 II is suffielest fer pressuri:e heater re= oval.

1.

Open the pressuri::: surge 11== drais.

- W..

E.

Drain Systen (Ps : III)

.*; m +1:,3.:x,

. ? art I & III are required for CTSC tihe plugging, core flood check valve repairs and re=cving an RC pu=p.

30!E For OTSC tube plugging. the OTSG drain trill also be openek -.

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.. 2.

No =s! Srsten Cee ation H t

This section vill describe how all the basic RCS operations inork' together to fe:= an operating system.

f The systa= e;erstions dese:ibed in this section reflect sorsal opersticas of an.NSSS.

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2.1 Resetor Conlan: Sv :e= Heatus Heatup cf the na::cr cool'as: 'systes %[ss the systes f :s a cold 7

shutdown candit:=n to a he's.sh :dow c=diti:n. The proced=e requires heatin: the reactor coolas with reac:c: coolant pu=p f

heat' while sais: sir.ing d e 'coola.mi a.6cocied by si=ultaneously f

p-increasing coolant pressure. Is addi:1 :,. par: cf the coolast is removed as it emp nds due to the increasing :sgerature.

[

L l

4 2.1.1 hatus Rate l

the'n the reae:c 'ceo! ant te=perature is below 300';, cutly three l

~

.pu=ps are alleved.to operate. This is :n preves: hydraulic lif.isg i

?

of the fuel asse=blies by the denser water. H:vever, the three pu=ps l

provide a sufficies: hea:up ra:e because the denser va::: requires I

more pq verk fer circulation resulting is a higher p==p heat i.put I

to the coolas:.

5 l

The avera t hes:=p, rate will be between 30 and 30';/hr. The higher g [

l the RC te=;erature the slower the hea:vp ra:e due to the==al losses i

to the savir r.=est and the decreasi g ;;=:p heat imput.

L 2.1.2 Pressure f.i=1:s L

• During heatup the coolant pressure must be regulated to st' y between a

high add lov' pressure boundaries. The boundaries vary with ta=pera.ure.

?

The high pressure boundary is 1= posed by 27, li=ics of the reacco

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vessel.

.Over a period of time, the mNm pressure ?'-8 for each heastp ~

~

,d

ste gradually be:=es less due :o the ac=.=:ulated radiation dose to the reacter vessel =etal. The radi'atica displaces a =s is.he l

crysta111:e structure of the vessei =etal maki=g the me.a1 acre r.

i

brittle, r

h The minim = ;; essure botadary is pri=arily igesed by reactor coola=2 g

pu=p h'PSH require =ests.

(

In additica,.ini=:= pressure requirements are i= posed by the press =re i i necessa:7 to keep gases in solution and to keep fuel pins is co=pressics i

to ensure hat c:=pressive cladding stresses esi.st a: reac.or ta=pers:t=:e l

F conditions f:: which hydride fo:. nation =ay oc==.

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74-r Appedix C to 10 CFR 50 spe:ifies the ini== fra :ure tough. ness requirements for ferritic =sterials o' pessure-re:sining c==pc=e=:s k

f of the R'*?5.

These reouirements are povided in the Te:anical Specifications for nor=al and test conditions as a pressure limi which varies as a function of rese:or coolas se=pers..tre and rate 6

of te=pera:ure change.

/

Overpress=e protection against exceeding these li=its is povided by (1) the pess=i:er safety valves and (:) the power opera:ed f

• /**"

i relief valves.

The pressure li=it is relatively low at low reactor coolant teep-eratures and thes increases to higher 11=its at higher reactor coolant ta=peratures. The Appendiz G li=ic was determined using the following:

1.

The me: hods outlined in topical reper: 3AW-10046, 'Hethods of Co=pliaace with Frac:=e Toughsess and operational Require =ests of of 10 CFR 50, Appendix G."

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RT shift predictions fron Regulatory Guide 1.99.

g 3.

Actual base metal and weld wire =aterial data (typical).

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Predicted acc:=ulated radiation.

I 5.

Design hestup and cooldown rates.

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2.1.3 Coolan

Pa-Eceter !nd! cation Durine Westus 6

g 3

+

The coolant dessure will be monitored by the narrow ra=ge and vide E.

. I range pressure,1ss trumentation.

The coola :: te=ee-ste e is monitored by the reactor inlet wide range te= sera:ure ns::. men:a:ics.

Te=pera:ure indications at other locations are not necessary (exce; is the pessuri:er) because the coolant t

will be in essentially an isother=al condition when at :ero power and forced co=1r.n: flow. In ether words, the te=perature will be p

assentially the sa:e throughou: the BCS ez=ep in the pessu.izer.

Pressuri:e; level inst:.anentation is used as as indication of k

coolant volu e.

3

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2.1.4 Paraneter C -t ol *

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The hes::3 -ste can be varied by regula:ing heat' renoval using the Seconcary 5ys:es.

wi.h the feedwater main sining the proper steam generator levels, the turbine hvpass valve or at=ospheric d:_.p valve saa be opera:ed to provide steam flow to. rs=sve hea: through.he steza i

generators.

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N The coolant e essure is remote manually con: rolled with the pressuri:er heate s as: spray.

is controlled by the Makeup and Purification Systes.

j I

The va:er 1. venter f

To acc =plass :::s, the flow through he 1e d:n li=e is se ather:a1 e.tps..sion of thet a

greater rate than necessary to ce=pensate f: Den the akeup flow is auta=a:ically con: r coolant.

a constar.t coolant volume by keeping the pressuf.:er Ievel cons ant.

s 2.1.5 AT 1.inits AT limits exis: be: ween the steam generator shell and tuireir an'd

)

D e tempera ures must.

between the pressuri:er and reactor coolant.

be centrolled to maintain the AT withis the specified li=its.

During hea up at lov Itc te=peratu es a vacuu= is created in the

. secondary side of the stes= generator ta pic s:e low te=perature This flow of stes= to the steam gesers:c; shell li=its boiling.

large tube to shell AT's.

=

=

. 2.1.6

$7A5 and'Co-e Flood Systes During These syste=s are isolated below certain R".S pressures.

heatup, after the pressure is above the actuation se: poi =:s of the War. 'sg

. systems. the syste=s are to be removed frs= isolation.

alar:s sound when he syste=s sust be reinsta:ed.

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1 2.1.7 Procedure t-1 l

As Initial Conditiens Prio: :o heatup. the R:5 is filled' and ve=:ed and th e a-

8* y and inst:t= en:stica syste=s are ; epared, of parti =ular i=per:ance are the Makeup and P.:.rification Systen and seconda.y Syste=s.

[

The Mr & P Sys:en boren con =en::ation =E-be adjus.ed to =a ch the RCS concent:stion. If the concentratica is less, the RC3 r

would be diluted when the makeug flow is est:blished. Also, all ion enchangers which can re=ove borea==st be isola:ed and.

the hyd:c. gen cover gas =ust be es:ablished for osygen scavenging of the coolant <

and In addition, the decsy heat systen is re=oving decay hea:

holding the RCS te=perature constant. The RCS pressure is app:nr estely 10 psig. nis pressure is provided by a nitragsn i

a i

This pressure =sists. ins the coclant supply to the pressuri:er.

at the top of the reactor outle: pipes sub=coled, thereby allowing circ'ulati'en of coolant through the locys whi=h is d.-iven by,

the Decay Heat Systen.

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3.

Prenare Pressur.*:e fo-P esru-, con::al ~

r bthelowlevelindication..

,,_1., Adjust the pressu=i::: level When the ICS power is increased from 0 to 15. 'the pressurizer level vill be allowed to increase to accommodate coolant a-p===faa.

,,,,.r 2.

Open the pressuri:e==11ef valve 50 isola: ion valve.

3 3.

Place the pressurizer sp;sy valve made svi:=h in manual.

r-1 r

d.

Energi:e all pressuri:e; heaters. When the pressuri:er wate: reaches satura:ica te=perature for the exis.ing pressure bleed off the si:rogen cover gas.

l C.

Preoare Wate Invento-y Ce= ol 1.

Establish a r all =akeup flow using the askeup flow cent:31

[<

valve bnass needle valve.

r 2.

Establish the 1e:dewn flow te et pensate fo: the RC pt p t

, seal in-leakage and the =akeup flow and system swelling.

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Place the pressurize level cont = aller in auscantic and

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set at the initial fill level.

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Start Coolsat Hestus g

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3. - t Reducs decay. heat syste3: cooling capacity.

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1.

Since :he ; essur-:er level centro 11er 1

Increase 1e:down flow.

2.

"is in auto, the saleup flow will autora:ically increase to 7

compensate fer the increased le:dow:. flow.

i Increase reac:c; coolan: ;; essure with pressu-izer heaters to f*

the pressure required to provide the NpSH for the RC pt=ps.

3.

Isolate the De:ay Heat System and secuestislly s: art" the F

Note before s:ar:i=g the RC pt=p or before 4..

three RC p=ps.

th's RC te=peratu;e rea hes ISC*F. seal inje::ica and c==ponent cocaing wa:er flow =ust be established to the ; p-=otor assc=bly.

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E.

Durin: Heatus'-

RCS te=perature and pressure and main:ala Monitor and ple:

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proper ;; essure-:c=perature relaticaship and hestup rate, 1

If desired during heatup, a bcron dilutica can be 'st.arte,d.

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. - 2.

Safety rods must be inserted prior to any dilucion. Operate pressurizer spray to maincais pressurizer boron concentration Addi:1cual heate'rs withis 500 pps'of the Reactor coolast.

b

.should be energized to c.aincain pressure during spray valva

+

operations.

Prior to reaching 200"F, vent all the contr:1 red drive r

3. ' mechar.is=s. (The RC pt=ps are required to be vented prior to sta::up.

~48' nen the coolant te=perature reachas 300%, start the

d. ' fourth RC pt=p.

t k

Circletien of Mest:5-i F.

non the soolant pressure approa:hes operating ;: essure, 1.

place pressu:i:er heaters is au::=atic control.

2.

Set secends:7 syste:f c:ndenser steam dt p valve to mLintain the RCS a: the requirec C*. power :c=pera:ure.

j 2.2 Ace;esch to Criticality __

- The approach to criticality brings the resctor coolant systa= from a hot shu:dewn c nditica to a ho: :ero power condition. The ; sced:...e 1

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requires rer:: i= neu: en poison f=s= the reac.or core t:stil the fission I

process beco==s self-sustaisis;. The neu::en poisen will be ce heric I-2 acid which is dissolved in ce reac:c: ccolas: and de centrol rod

[

asse=blies.

2 5.

Prior to dilutio= and before the reactor is critic 1, the safety rod r

groups (1 thru 4; =ust be vii.drwn.

2.2.1 Me.ite-in: C-i:ieal A= -each i

I.

P Neut:c sour:es are provided for sscritical==.1:1;11ca:ien and

. a monitored : itical ap;;cach.

2.2.2 Bo-en Re eval l

I

(

Baron is re=oved from the 105. This process requires adding da=ineralized water

.to the RCS @ ile re==ving rea :or c=olan: to =ais: sin de wa:e inven: cry ti constant. Du-ing this ;;o:ess, the rese:c coolas: ;- ps pro.-ide

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g 1

sufficies: =i=i=g to keep a ho=ogeneous.berca =cace= :stion. The re-y.

sulting bore: de:: case will be a 1cgarith=ic fun :ima.

2.2.3 Cent el Rsd h*ithdraval '

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.The control :cds are withd:=wn in a g sup sequence. The sequence F

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requires vicd::ui=- the control rods =eares: ce care peri;he y firs l

then the nes closes: e::. The sequence is to ;;; vent rod shadowing i

of the neu.:en date:: ors which are loca:cd ex:ernally to the reactor vessel.

2.2.4 Precedure A.

Initial Cenditiens g

1.

The reactor is in a ho shutdown canditica.

l [

2.

Record intitial data for the sde:itical :szitiplication, j

3.

3:a-: Critie:1 A.. ach L

1.

3:ar re=oving boren or c"ca:=31 rod asse=blies, k

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Du-inr C-itical AM-each r-

.a 1.

Maintain all pars =eters c=nst=t: which 'will affec. reac.ivi:7

(

escept for he c=s :mi roda or boron.

2.

Make a plot of inverse suberi.ical multiplication.

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_ _ _ _ _ _ _ _. - - _..,... _ _. -.. _.. _. _ _. _... _ _ _,.. - -.... _ _., _.. - _. - _. ~

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3.

During bc =n dilu.ica, frequen: rese:= coolan: be:=n cen-i l

centratica =cas=c=ents will have to be =nde.

In c de: to obtain good data, :.e hers-ion ;;ocess should be done with a cons: ant.le:d=vn flowra e.

i D.

Ce=cletic= cf critical A-- =ach t

E 1.

When the rea :c; is critical dis:en.1.ue barca re=cval o":

Control rod widd: wal and keep RCS in a Hot :ero pawer conditics.

2.3 Power One stien Power operation includes power in= cases anEl de= eases and steady t

state cperstics be:veen ci and 100*, power. A: ;ower levels above 15% power, de rea::o ushally is c=ntrolled auteca:ically by de I

Inte. rated Cent c1 Syste=.

However, -he reae:= can be =anually controlled, if desired.-

i During power operation, the pressuri:e; pressure and Icvel are

[

au:o a:ica!!y =a=..sined cor.stant. The rea ::: coolant eve see

. ae average ta=.perature cecreases linearly vid de::casi=g ;cwcr.

E te=se ::u e is.kep: ccas: ant dove 15% power. Selow 13*, p:.cr I

p f

During'pever cha=ges, the power defe: and Tecca and sa=ariun concen:: :icn is the c::e will change.

his will require c, pen-sation wi.h c=nt:ci rods and boren.

i When the RCS is being centrolled au:c=atica.117 by the Integrated

}

L

, Cont:cl Sys:c=, it will follow d e hes: load de= ands cf the Se:cnda:y t

Syste=.

Fc: exa=ple: if the secondary s:can flow is increased the t

R3 power level w:11 ir.=eas e to %eep the ave age te=pera:=e===s.a=:.

In addition, the RCS has feed fe:vard c=ntrol. In o.her w=rds the f

f ICS anticipates v..a: a :1:ns will have to be =ade and ini.ia:es i

E them early, dus redu:ing syste= pe::urca:icas.

i i

However, when the R 3 is being =anually cont :11ed the opposite is true. Fc exa=ple: the RCS power level is in:: cased den ce seconda. y stea= f!,=w will 'be in= eased to =aintain de RCS average 4

t te=perature cens ant. The average te=pe:a:ure is the average of t-the reac o: inle: and cu:le: ta=peratures.

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2.3.1 Pewer 7ne-ease Usin: 1*5 Con -ol_

2:ed Control Sys:s=

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With an innease in power de= nd, the Inte;:

ialtiates cc=: 31 end =c.ica, chage is feed ficw sad chs Ze in A: ce sa=,.1=e, ce res=:or t=bise th::::le v 14.e pesi lon.

syste= average,te=pers = e tends to de= esse due to the i: colas:

increased hea:

=sfer f:= the ssc.or coolas: ~.o ** seconda 7 L

Cn a dec: esse in res=:or ecol== te=pers:=e, the c=

oi F*

system.

systen soves reds to retu=n :ne syste= averste te=perature to no: al.

'"he deerease in na :or cools =: aversge s=pers:: e also causes an oussu ;e f: = the p essurizer'resul :ng in a de:nsse in

' pressure. This, in t=n, will energi:e ce press =i:e hes:ers to enintain systa= opers:1=g p; essure.

The extent of :od =otion, de= esse in pressure and.i=e to retu=n c: ditiens, a:e functic=s of the : :e of power change to equilibrit=:

and ti= dura.ics or ce si:e of the step increases 1: Power.

r.

2.3.2 Power Ine -ese with Pa-na! Centrol To increase the pews: output the centrol red asse::blies are withd.:pra or baron is re=oved fr:= the enolant caus1== a sli;ht increase in Al=os: si=ultaneous wi:h increasing RC5 pressure and ta=penture.the sec=nca.7 stess flow is 1.creas ed whim reduces the..m....*. -.-4,...

- p..

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the PCwe 3:5 pressure a=d : =pera:=s. Du:i== the chan e the pressur :e:

e

' pressure a=d level cent:cis will maintain the P.:5 press =e and I:

water invente:y ielatively no:=al. The power. cha=ge is done.in

~

several s=all step changes.

2.3.3 Power Deeresse Usin: TC3 g

For a decreasing power transient, the reduction in stes= flow and 3

increase in rea::c: co=12: te=pers: ce initiste sd i=se: tion.

I, A pressuri:e ins =:e occ=s whi=h c== presses the s:es= hub'cle and j[ ; )

The press =e increase a=: a:es the in=tases sysses pressure.

u::: in:o the y

pressuri::: spesy valves which spray reactor inle:

stea= space to c:noense stes= and -d-.ain the p-essure at the desired value.

C=i=

severe load dreys, the :.=bine bypass will L

open to assist in s: shill:i=4 s.ea= pressure.

l The most severe decreasing power t=sasient nor= ally encou=:end is 4,7:st!-

I l

that of a turbine :::p at full power. In this case, the cc=: o1 syste= will au:c==:ically run the nacto ;ower back to 13% full Ste= will flew th:cuih :ne :.-hine cypass to the c:= denser,

(

power.

and a:=espherie ven: valves, and if necessa:y, through stes= safe:y relief valves.

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2.3.7 Yater W.).eus to RCS Ikaring operatica, reac.or waier sust be added to the RC5 to cocpensate j

for leakage. The los: cf reac::: coolan: requires replace =ent by 4

adding a'nixture of berated'wa:er and de=ineralized water to the =akeup i.

sark. The por:icas are such 22-he r.ixt=s vall have 511th:17 less I

or the sa=e borsa c=ncentration as the rea :or coolt.nt. If the a=ot.nt ~

is slightly less. the rods will be alightly inser:ed each ti=e a makeup batch is added to the syste=. This will offse: the gradual rod with-

.f drawal required to co=pensa:e for fuel de;1stion.

2.3.8 Ventinc $len-Conde.sible Cases I

Non-condensible, ' gases vill eccumulate in the pressurizer durkng operacion. These sases cust be vented, otherwise the stcas volu= will gradually be diluted ':y the gases. If the

' pressuri:er stes.s space beca=e partially filled with non-condensible gases! the RC syste= would st be as capable of sustaining the load transients it is designed for, because the ability of the pressuri:er to behave as a, sur.e cha=ber would be reduced.

7

. To assure preper prHsuri:er perfor=sace. the total acn-condensible

. gases in the pressuri:er should have a par-isi pressure below 10 psia.

The non-condensible gases are vented through the pressuri:er steam sample line.

2.3.3

%enon and Sacarit=r T-r.sie.ts

'L Following a change in reactor power. the a=omt of Zenon and Sa=arium g'

poisoning will change wits ti=e.

Baron changes will have to be made to compensate for the resul.ing reactivity effects.

r After a newer reductien. the senen concentration increases to a

. value spram xenon) in about eight to ten h urs and then slowly decreases to 'a lower equilibriu: c= centratics ccrrespond1=g 7

to the new power level.

After a newer ine ense, the ze.on c=ncent :i=n first decreases to a value less : nan :ne ininal power ecr.ilibri== value and then slowly increases to a hip.e: equilibriu= concentrati=n.

The magnitude and dur:ti = of the menon i=duced reac ivity change I.

depends on the initial cperatihg power and he magnitude and duration of the power change.

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-2.3. 4 Dec easin: Pever w!:h P.nual Centrol t

L The control rod asse-blies are inserted into the reactor core or boron is added to ce rea::or coolast. This will result in a level.

sligh's de : ase in RCS pressun and ;::casurize:

As.the Reactor power is decreased, the seconda:y systen steam flow is reduced in everal s=all step changes.

/

t

. t

+

2.3.5 Pa 3=eter Behavior E

The RCS pressure and pressuri:e; level "are kept constant during.pcwer f,

i However, changes in reac:c: power level will cause case operation.

parameters to be slightly perturbed. Af:er being perturbed, the values t

will be retu:ned to their at:=al values.

E

• ~

The RCS volume flow rate is always cons ant unless the number of L

opera:ing pu=ps is changed.

'r The RCS inlet and' outlet te=peratures vary with power while the average ::=penture stays es..stant above 15*. pove as sh=en.12. Figure 1: ce power range between :ero and 15*. power, the average R05-22.

8 The inle: and cutle te=pers.

ta=perature inernases approxi=ately 3C..

This is because tures always change with a change in power level.

the axial LT across.he core changes proportional to power level.

F Mve 15% power, the average te=perature is kept constant because the level in the steas genera:or is allowed to vary, thereby changi.u

=sfer surfa:e of the sube o el d liquid re: ion. M the the hea:

RCS power level is increased. the stes= generator level is also in-creased 'so as to -ais.ain.he average to perature cons. ant.

[

,3elow 15% power, Se average te=perature will change in preportion The water 7

to power because the steam generator level is held cons. ant.

inventory L

level is not further reduced belcw 13*. power because a va:e margin =ust be available in the stea= genera:or far decay hea:

h" removal.

or for unexpected ::=nsie=:s in the low load range. Therefore, a constant surface is the boiling sectica of the steam generator is maintained.

s 2.3.6 Cc= e-satin: _'e-Feel De :letien f

During. steady state cperstion, the height o'f the regula.ing control tods is =sintained wi '-4 a specified band.

P As.the fuel depletes, the rods are withdrawn tntil they reach the high side of the band.

i At this 11:2. the opera:::s are reenized to dilute the RC system boron causing de cent::1 :ods to be inser:ed. The dilution is l

stopped when the rods reach the anzinal positica (=iddle of

[

band).

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l The sa=arim affee.s due to power chan:es are si=ila: to those caused by the zen:n..u.cwever. de s-a-it= effe::s are s= aller and occur over a period of days instead of hours as does the menon.

12 Although the fissica produe:1:n of %e ceases when the reactor is i

135 shutdog, his iso::pe c::i:inues to be ;:odu:ed as a, esult of I The Xe "

n=e=::a: ion

• i

' S decay (24,= 6.7 hr) present in the systa=.

L vi'11 increase to a peak value i= a,,...zi=a

ely 6-10 hours, afte:

ndLich its E de:ay (: = 9.2 hr) be==es the ;;ed--inan: factor.

The concentra:::r. then decreases vi.h a half life of 9.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

l 149 s

After shutdown 5:149 builds up as de a:c.= lated Ps decrys.

I

.i Sal 49 is stable and re=ains in the rea::or u.til :he reactor is I i ret 1.ed to the critical state, whereupon the 5al-3,.i.3 re=oved by P

neut:ca absor;;ica.

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2.3.10 Ie en oscilla:!cas t,.

i *

. Another phent=ena which occurs in relat ve y 12:Ze reactor cores i l is axial xen=n escilla:icas. This is controned by the axial powe:

!*r l

shaping rods.

2.3.11 Three reac:er e:alant.-._ =s ere-atin:

f-With three reactor cool:n: pu=ps operating, operation is si=ilar t'

to normal opera:ica except fe the power 1: balance between.he loops and the reverse flew.h = ugh the idle reactor ecolas: m.

t The load istic be: ween the stes= generators is c.nt:c11ed :o abou.

S

• 2.2:1 by cont:31 cf feed wa: : flow' to each steam generator.

L The nazi = = y=ver level in this mode of ope:stion is 73% of full g

Power.

2.3.12 Two reactor coo'.ta:==es ese stin: - cne in es=h loeo Steady stata c:ntitions for operating in his node are very sinilar h

to no:=al ope:s:i:n excep: fe: reverse flow 2 ough each idle reac:or coolant pu=p. The stes= gener::ces cperste wi.h balan:ed load.

The maxi =:= power level in this made of operation is 3M of f*uli r

m.

L 2.3.13 P: seedu e to Ine e:se Power N

'I A.

Initial Cenditien s

t Prior to increasing power, te rese:c is a: scue steady s. ate power level with the.Pressu=i:e pressure, level and ta=pers:ure being.ain--Ned f=1:1r cons.=.

I l

Babcock.Wilcox i

-- -~

r

~

- m

• m-

^,!

, - - =. - - - -., -

i G 0364 E _s rM i j

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__.._-.___.______.~.._.~_,I.

_,2 mu

._.m.

.m_

m an._

l' 84-e J.

Star: Power Ine-e se To initiate a power increase, a co==snd is given to the ICS g

h~nen below 134 power, it is to increase the power level, manually increased by withd: swing c:n rol rods.

~

/

C.

Durin-Pever Increase _

i When the power level is initia!!y above 13*. power the re1stier. ship bc:veen the rea= :: Power and 203 aver.. e te= pea:ure is c5 served.

If the reis:icaship dalls below the eiesired value. Iwer the f

If the relstionship is above the staan geners:c: water level.

This P

desir d value, raise.he s:esa geners:c: v-ter level.

will assure ths: he s:ess generstar liquid is at the prcper level when the reac:c: reaches 100% power.

t D.-. Co. ole:len of Pever Increase

[

The Pressurizer pressure, te=perature and level are brought to no:=s1 and the RC3 is as a higher power level.

i.

~

2.3.14 P seed:-e te Se:resse Pcwer...

k-A.

Initici Cenditica Peier to decreasing power, the reactor is at se=e steady siste power level with the Pressuri:er pressure, level and ta=perature m

being r. sin zined fairly cons. ant.

L 3.

3:::: P'ever Dee esse t

i To initiate a power decresse, a coe=2nd is given to the ICSHowever, belcw 1 to. decrease power.

-in enanual by insarting centrol red asse=blies.

L L-C.

Durin: Pever Dec ense 0

The pcwer is reduced at a :ste which main.sirJ the pressuri:ar

[

level at the specified level c: higher.

f.

.D.

Cer==letien of Pever Deeresse i lly

[.,

.The Pressuri:gr pressure, te=pera:ure and level are au:==st ca returned.o ac:=n1 sad the RCS is at a lower power level.

l r

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.j 2.d Brin:ine P.esete-sub -ities1 This p:o:sd=e brings the resetor from a Hot :ero powe cond ion to a Hot Shutdown c:nditi:n by insertin: =c= :31 rod asse=blies.

After bein; placed in a Mc: s.u.down condisson, the senen ccnce=:::: ion' i

in the reactor will chsa:e. T':.is say recuire addag =on neu:ron j

' poison to keep the RCS at least it, ak/k ascritical.

y I

- During this cpera:ics. the R:5 pressure and te=pera:ures and the

)

(

t pressuri:e: level is kep cons: ant.-

r

+

2.5 Resetor Coel== syste= cect Down j

r Cooldown of the rea :o coolan: system brin;s the sys cm fran

• hot shutdo.T. c=nditica to a cold shu.down c=nditien. The ;;ocedp, T

e P

recuires cooli:g the syste= using the stea= genera cre above 280 F

~3

,C5 and the Decay Hea systa= and steam generators below 280 T.

a

')

heat is co= posed of residual hes: and decay heat.

• ~ *

,h.

The pressuri:c is used to keep the coolant subcooled.

.h During the cocid:m p;cesss, pa::icular attentica =ust be made to the coolant bc :n cen:ent stion.. The baron c== ent :: ion w.st be s

E sufficies to ove.-- e ne core rea::ivi:Y in: s2se due to the

. l..

E decrease in coolas:

e= pen:=e and to sc=on decay.

.t 6

g E

In additica. water==st be added to the RCS to co=pensate for coolant

(

)

contraction due to the decreasing te=perature, i-

~

.il m

. 2.5.1 Cooldom s

The cooldown p;ocess is ac=o=p11shed ili :wo phases. The first phase f

5 reduces the reactor cocir.n: system te=perature using the stes= genea A

rators. This is or= ally dine with one RC pu=p de.eneg:sd in each locp to 11=1 heat i=put to the RC..The ms also provide

)

normal spray flow to the pressu:i:ar.

.s*

,h Below itS0?T the steam generate: can=ct effectively ecol the system.

j Therefore, the dicar hes: system is required fo: re=oving heat.

(

~

h Note that d:..ing c=oldown below 2'30'T the prl=a:y pu:,ese of the p

staan gener::crs is to s=ove heat f:en the RC loops by e=hanci=3 4

loop flow.

When the DHR$ opera: ion is established, the RCS temperature must be.

r held constant while re=oving decay heat with the steam senerators.

t This 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> hold is to reduce the staan generator tube to snell AT.

h.

=

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2.3.2

'*Swit ch-over?

/

r.

Prior to chan.-ing the cooling =ede f:c= ce stes= generators to the i

^

Syste=, ce RCS pressure m:s: be adjusted so : hat it is t

Decay Hea:

below the design pressure of the DH Syste= and above the N75H require-mes:s of the RC pt=ys.

2:ted to the he RC pt:ps should be ;s=sning then the DH flev is s:RC vessel so da-the i

~

n is will also the RC and li=i

.ht =al sheck to RV and internals.

Provide continuous Sc:ced flow through the core.

2.5.3 Cas Produ::len_

l.

As the pressure is reduced, non-condensible gases will co=e out of r

These gases should be re=oved by c:n.inuously ven ing solution.

thr= ugh the stes= ;hase sa=ple line and :he 1e:devn the priss =i:::

flow degased by the P.J5P systen.,

t 2.5.4 iann Additian_

s During. cocidown, the reactor is to be kept at least 1% Ak/k subcritical.

g his recuires adding bar:n to cocpensate for the ness:ive te=pera:=e In addi:i:n, if the cooldown follevs a period of power

• operatica, the xenon c ncentr:: ion will eventually decrease below its coefficient.

equilibrit= value (after s18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />).

' his also adds sac.ivity and needs to be.co-jensated with boren '

e addition.

However, the most ecc=c=ical The baron can be added ;;ior to cooldown.

This is true fo: two reasc=a.

sethod is to add bc :n Mng cooldown.

First, the bc::n c:a he added during the cocid:vn prozess to save Second, due to c:alant con:rse: ion, water will have to be If berated wa:er is added to cespensate for centes : ion, less time.

added.

g water pro: ssing win result.

2.5.5 Parseeeer coneral t

The cooldown rate is controued by the secondary systen and by the,

decay hea: system.

I P

The cooldown sressure is manuany controned with the pressurizar heaters and spray.

The water inve corv is controlled by the Makeup and Furification r

System wath ene pressurizer level controner in auto.

L Babcock & WHeox j

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2.5.6 STAS and core riood svste, seteoines t

During pressure reduction, these systems =ust be isolated before F

l i

reaching the actuation setpist.

L j

2.5.7 N Ad i t " ?"# "I C !J **

2 When pressuriser pressure is reduced te near, the saturation pres-g aure for the loop te=perature, nitrogen is added to the pressurizer E

steam space to provide systen pressure control. The N2 pressurs

?

'. maintains the high point of the reactor coolant loops subcooled l

l

and provides a driving force for the letdown flow..

g The nitrogen te=perature at the point of igjection must be no

, colder than the piping material minua $100 T.

t 2.5.8 sorav nov During cooldown to 250*T vith forced coolant circulation, pres-g L

surizer spray flow is provided by the driving head of the RC pu=ps.

[

Af ter the EC pu=ps are de-energized with the DE system in operation.

the pressuri:er spray is provided.hrough the auxiliary spray line from the DH system.

y When the E te=p'rature is reduced to refueling tenverature, the e

pressurizer spray flov is continued to remove the heat in the pressurizer metal.

o

• 5en cooling down to 280 F bv. natural circulation, the pressurizer 1

l j

spray is provided through the aim 1Sr7 spray line from the makeup and purification system.

Lace nov Suri.=t DR Re= oval 2.5.9 To help maintain loop f. low in the loop with the surge line, the following procedure is used.

+

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Prior to DH syste= operation the press =i::: level should be lowered to a' mini =:.m level bu. above hester interic.k. tihen re.,cving decay r,

heat by the CM systa= opers:ic the presse.:e wa: : level will be

(,

gradually increased. his will " ': the a=sm cf hot wa:e flowi=g ou. the s=ge line as water is added by the pressuri:e spray.

The het wa:e flowin ou: the s= 3 line has a tendency to s :p flow I

through that Icep by upse :ing the heat balance. The hot water tends 4

to try and reverse ha natural. r.everse flow rough the loops.

p i

2.5.10 Procedure i

3 i

.h.,,, Initial Conditie.s l

Prior to cocidews,. the RCS ta=perature is being =sintained constant by the secondsry systes while either four or two reac:or cocIss: pu=ps are operating. The WGP systa= is r.aintaining the required wa:e inventcry and the RCS bo ca concentra: ion is sufficien: !== keeping the cere 1% Ak/k i

suberitical. The pressuri:e is main.aining the system pressure.

h B.

Preot-e fer Pressure Reductica

~

g j

1...

Turn off all pressurizer h.aters.

i 2.

Put pressuri:er' spray valve in manual control.

i C.

Presare Vole =e Control j

increase pressu=i:e level to high level. The level wi.11 be L

l retu:ned to nor=al by coolsa: con::ac.ica during cooldown.

During cz=1 dows with the 5:es= Genera:crs, the p.=:ps are rening j

j which requires seal injection flow to pu::ps. However, du::ing J

the Decsy Hes: System eperatica, the makeup system can be. semed after the RCS te=perature is lowe:ed below the te=perature i

which is ha: 5.d to the RC pu=p seals

• 150*F.

i r

1 l

D.

Preea-e P--ssu-i er Vent'_nr 8 4

Open the ss=ple line to the pressu=i:e; staan phase and bleed i

to Kl47 systes.

i E.

Preeare 3eren Cen re!

~

Add boric acid to the RC system to p:oduco he desired RCS baron concen. ::ics at end of cooldown.

i

+

I i

l t

i i

I i*

l Babcock &Wilcox I

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m-

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v=t e-,-w--pw--ww-+-

--g+

ww, gr.w,r,-e

-.mry-g w

yw--mgea r - 7 e c y w n,.w vm---,--.----m--eww

--m---ew-+s-*w-+w-w-t-i-

i s

_.m_____

I n-I.

l

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l.

F.

_laisiate ceoide.

s 1.

3:op ene RC pt=:p in each loop to reduce hea: input to ecolant.

r 3'

L

/

2.

lac saae turbine'h>,.a.ss flow to achieve desired cooldown E

zate.

4 l

C.

Diarin: Ceo! dss 1.

Monitor and plo: RCS te.=pera:=e and pressure. Mjust l

l-pressure and te..pera:== :s s.sy vi.hin specified li=its.

I Before reaching lov RC ;;ess=e : 1p se: pein:

put I

RPS in shu:devn by;2ss and withdraw safe:y CEM (C oups 1-4).

..... Bora: ion and centractica =2ket:p should be c==pleted prio l' :t to placing CH syste= in service, thile conduc.ing bera ics.

e 3

and contra::i:n =akeup addition, "'a * nor=al operati.y;

[

u 1evel with auto con :al, 2.

Sa=ple and plo: RCS bor=n ec==en::ation to assure ?%at the

[ 7-%W5C:#M' 7/Ccr.m.;. i.RC5 is bein; =ain.ained a: least 1*, t.1/k scheriticai, y.

I

.'RI

3.

Below 280'T adjust pressure for switch-over".

I

~

I b

a.

Reduce pressuri:et level to.fus above hea:e i=:erlock.

l f Fist level cent:o1 is =m=us2 :hc:

level p*

during ceci d:wn.f := 250 to 140,:sise pressuri:e:

s.

7 to 21=it flow from i

pressuri:e to RC pipe.

b.

Ini.iate the Decay Hea: Systea

~,

c.

Stop al'. reactor coola=: ;=ps e.,.

p-d.

Ins er con :31 rods before ROI ta=perature/ pressure co=bina:ica approaches =1 required to hold the dissolved gases in solu::en.

When RC p;ssst. e and te=perature is below the CRCM venting e.

limits and C:c!'s are fully inserted, ves.isg of the CEM

~

may begis.

4.

Centi =ue to re=ove heat with the steam zenerators to augment coolant flav through the RC loops for loop cooling.

?

5.

Md nitrogen to press =ize; as necessary to pressuri:e RCS and e

to keep R:. Ic=ps su:c=oled.

r t

H.

Cor= le ics j

(

I l

1.

Sect:r and isolate )*.Jg? System f;os RC3.

I 2.

Use DH Systa= to red==e and :sta coolant ta=perature i

at desired value 1

• =

S..a. b.c.o.c.k a Wilcox b

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D

• The taactor Coolant System has been designed to be as compact 6

as possible which af a4+es the amount of energy that can be released k

5 during an hypothetict.1 loss of coo M t accident.

The co=ponents in the Reactor Coolant. System are designed sad i

L'-

I fabricated to AS.'fE Code Section III and ANSI 331.7.

g.

c t E The components are designed and analyzed considering all identi-fled mea u i"t, pressure and ther=al loads. This includes evaluation

)

for seismic and LOCA.

e The operation of the reactor coolant systes will be monitared to L

s p... j consider the effe,ets of radiation on the material in the reactor vessel and the associated shif t of the reference transition temp-l areture c=:g.

j ;

S

[ [

?I-Emactor coolant ta=perature controls both heat input and heat renoval.

s e l

Esat input is provided by decay heat, nuclear heat during power operation, p

8 t

a and reactor coolant ptszy operation. Beat removal'is provided by the g!;.

2

, secondary system (above 280T reactor coolant temperature) and the decay I'

heat renoval system (below 280F reactor coolant temperature).

t Emac,cor coolant pressure controls both pressure increases and decreases.

T I.t l

Increases are provided by the pressurizar heaters. Decressas are i [.

Provided by pressuriser spray /RC pumps (above 280T RC ta=p.), ~ 4147

{

pressurizer spray (below 2S07 RC ta=p.), and power operated relief

. n r

valve.

{. [

s L Isactor coolar.: flow is provided by EC pump operation when DERS is isolated and natural circulation when the reactor is suberitical.

+

s-RC isater is added by RC pu=y seal injection and nakaup flow from the r

makeup & purification system. Water is tenoved by leakage and letdown i

I flow to the MC&p system.

i During cooldows N is added to the pressurizer at about 35 to 30 2

pois to keep the EC bot les pipes subcooled.

I

~

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ti Excessive hydrogen is maintained in the resceor coolant systee to combine with oxygen. This gis must be. razoved, before opening,

((

the reactor vessel for refueling. The hydrogen is rs=oved through

~

4 the makeup tank veut as the reactor coolant passes through.

p e

il j

Noncondensible gases are vented just prior to draining the RCS and afcar filling the RC3. Vents are Incated at the top of the CEM.

e pressurizer and RC hog leg pipes.

=

e Chemistry control is pri=arily concerned with controlling oxygen, L

i a

r pH C1 and 7 and dissolved solids.

above 400*F and

~

(a) oxygen is controlled by adding H2 hydrazine below 4CO'F EC tenp.

~ :

(b) pH is controlled by adding Li.

(c) ' C1 and Y are rs=oved by the purification de=ineralizers

.r of the nakeup & purification system.

i (d)

Solids are renoved by the denineralizers and filters of J

r the HU&P system.

During beacup and cooldown the RC pressure must be kept below

~

the K! g of the reactor vessel and the DERS relief valve setpoint, l

when the EERS is engaged. 'It must he kept above he EC pu=p 3p53

, i J.

and seal staging pressure when opera-J.ng EC pu=pe, the fuel cocpres-sion limit, the limit to keep dissolved gases in solutien. and satura-h t

tion pressure (except pressurizer). _, _,

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l Figure Ecs,-14. Pressuri:ar Pipbg Arrangement /

t L.

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Reisef He ader~

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7,a.

Decay Heat Re moval t

4, System I

Y g

I V Ausiliary I

Jk SP.*ay Vatve -

F x

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Lin, m

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V Samplans Line i

a L

@~Sprav Line j

Nit e'egen -M Pre s sertse r st inimum L

1 I

><>-G-n. vaive v,.J un, _

l N

l-Heaters 3

,,7 7

9 7

valve Ng M2 I

i

= :*-

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8 Drain l

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. RC Cutlet p."-

(36. tach Lanet

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d' Figure ES-13. Fressuri:er Level and Te=per-r

}<

ature - Operating Fara=eters E.

i

=..

e

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Pressurizer 410

_ Upper Connection for Connection Level Transmitter i

r

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400"

-Maximum Level.

f i

Indication

=

315" High-High j i.

Level Alara p

I 260" High Level Alam F

{

220" Normal Operati=g Level i

,. ;. 7..

200" ' -

-. Low Level..A.laru

,e....-

t.

....y t

s go

,_, Low-Low Level Alarm acd Free-p a

surizer Hester Interlock l

63.5" Top of Pressurizer Hesters Pressuriser o"

_ Lower Connection for Connection Level Transsisters L

t L

Teen Nomal Alarm /loestion

(

648.

662/ computer Pressurizer (liquid), y Surge line. F 635 IEA/ computer Spray line, F 532 - 380 520/ computer

[.

ET discha'rge lines, F 120 200/ computer

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-E Figure RCS-16. Reactor Coolant System Arrangement.

Elevation i

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surttr NCllit e

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he Babcock.Wikcnt I

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Fis.ure c -17.j IleactorCoolancsystenA/rangement-Plan

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21' # ~

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