ML20024B371
| ML20024B371 | |
| Person / Time | |
|---|---|
| Site: | Crane, Davis Besse  |
| Issue date: | 11/20/1979 |
| From: | Wallman D BABCOCK & WILCOX CO. |
| To: | |
| References | |
| TASK-02, TASK-06, TASK-09, TASK-2, TASK-6, TASK-9, TASK-GB 69-1106003-, 69-1106003-00-0, GPU-2467, NUDOCS 8307080573 | |
| Download: ML20024B371 (37) | |
Text
-
spy aySF
- e. '.s -<
t
\\
l a
ss.ticscas.03 i
Ma x.tw 1373 i
!d a.
t l :l
.,o E
9 i
i i
l e-
- l SMALL BREAK OPERATlHG GUIDEllHES
! 'i DAVIS-BESSE UNIT 1 -
i. r:
.t.4
{
1.I i4 '.
1
.a e
~:-
t iln
- b h, 1
CONFIDENTIAL i
COUNSEL ONLY lln
- . I t
n..
s5.,-
.T20127
-n i
- (
.. : ;-u.
a.. -... a.
.;}
.... ~ :
-.......: * ~
~~
d.-
.~-.
~~
- , Ba bc o ck & Wilcox i
4
~.,,
q 4,.
q.-
_., a:.._ __ _ _
~
- "~.'*'~~~~~-~--..,
83070BO573 791120
"" ~ * ' * '~m' :,
PDR ADOCK 05000289
~
P HOL
e..
s o
l g g
,{
S:T?-2000t. (6-76) err BABCOCX & WILCOX NUCD4 PCwit GENT 2AT:CM Devr5;CN TECHNICAL DOCUMENT e
~
E'4ERGENCY CPERATICN SPECIFICATION 69 1106003 - 00 Doc.10 - Serial No., Revision No.
fo.r SMALL 3REAK OPERATING GUIDELI ES DAVIS-BESSE UNIT 1
?
PAGE 1 Tg()128 i.
. o e
- (
.5 3'ai?-20005 (6-76)
SABCOCX & WILCOX Numett wuC.I.A4 PCwit CINta A004 Oiv'1:C N RECORD OF REVISION 69-no6 coa-co REY. NO.
-- CHANGE SECT / PARA.
OESCRIPTION/CH ANGE AUTH0212AT10N 00 Original Issue - D. A. Beckner Cus:c=er Serrices PRE?ARED SY /
/7 DATE Cp)
'(Ti:le)
M /
b DATE //
APPROVED 3Y
/
e Cit::Lej -
/ (Il:le)
APPROVED 3Y fb T/a.A-b Cw DATE Il ! Z,,, [') 9 f
~
a:E') "
- (Ti:le) s e
/ '!1 7 < Y
'.; f/M /%w/
DATE APPROVED ST (N e (Title)
APPROVED 3Y I,
DATE (Na=e)
(Tple) f l
T20123 DATE:
u-1-79 PAGE 2 OO*
- M g*
6 g
g e
l
.a
,l, D'.1::"-20006 (6-7G)
DACCOCK & WILCOX N u ita NbCLIA2 TOWkt GENtt A00N Civ$0N 69-u06003 00 TAS!.! 0F Cm' TENTS /EFFICT!"E PME UST SECTIOq
' TITLE PAGE 00 0. li0.
PART I OPERATING GUIDELINCS FCR SRALL UP.EAKS 4
69-1106003-00 1.0 SYMPT 03G AND INDICATIONS (ISSODIATE INDICATIONS) 4 69-1106003-00 2.0 ISDEDIATE ACTIONS 4
69-1106003-00 3.0 PRECAUTIONS S
69-1106003-00 6
69-1105003-00 7
69-1106003-00 8
69-1106003-00 4.0 FOLLCt.'UP ACTIONS 8
69-1106003-00 9
69-1106003-00 10 69-1106003-00 11 69-1106003-00 12 69-1100003-00 13 69-1106003-00 14 69-1106003-00 APPENDIX A LIP CCOLING 15 69-1106003-00 16 69-1106003-00 Figure 1 Pressure-Tempere:ure Lidit Curve to Preclude nesctor Vessol Crittle Frocture during RCS Depressuri:ation Eclicuin;;
Acciden: Conditicas 16-1 69-110'003-00 Figure 2
!!inimum Required HPI Flow vs.
RCS Pressure 16-2 69-1100003-0C Figure 3 Core Exit Thertoccuplc Tc perature for Inadequate Core Cooling 16-3 69-1106003-00 PART II SMALL CREAK PHENCSENA - L2SCRIPTICN OF PLANT BEHAVIOR 17 69-1106003-00 1.0 INTRCDUCTICN 17 69-1106003-00 2.0 IMPACT OF RC PU5@ CPERATION ON A SMALL.LCCA 17 69-1106003-00 18 69-1106003-00
, c
- 3. 0 SSMLL 3REAKS WITH AUXILIARY FEEDNATER 18 69-1106003-00 19 69-1106003-00 20 69-1106003-00 21 69-1106003-00 T20130 DATE:
11-20-79 PAGE 3
.m'heg44-g>ee
.[..._
e.)
(
3'.3P-20006 (6-76)
GAGCOCK & WILCOX sumata wuctru ecwee op.te..nos ems:c" 69-110e003-00 TMRE OF CC"iENTS/EFEECT!"E PSOE UST
$_EC Tin:!
TITLE PAGE 000. f!0.
S.O SMALL anEAKS 11ITICUT AUXILIARY FEED %ATER 21 69-1106003-00 22 69-1106003-00 23 69-1106003-00 6.0 TRANSIENTS T!!AT MICIIT INITIATE A LOCA 24 60-1106003-00 7.0 HPI/MU THROTTLING 24 69-1106003-00 25 69-1106003-00 FIGURE 1 BREAK SI' ECTR'JM-AVEP, ACE SYSTEM VOID FRACTION WITli Tile RC PtAtPS OPERATIVE AND 2 HPI PUMPS 26 69-1106003-00 FIGURE 2 PRESSURE VS TUS-SMALL BREAKS WITH AUXILIARY FEEDWATER 27 Q9-1106003-00 FIGURE 3 FRESSURIZER LEVEL VS TUlE - SMALL 3REAKS WITH AUXILIARY FEEDWATER 23 69-1106003-00 FIGURE 4 PRESSURIZER LEVEL VS TD2 FOR S MLL BREAK IN PRESSUR1!ER 29 69-1106003-00
~
FIGURE S SYSTEM PRESSUTE VS 702 - S:*.iLL CREAT.'s h*/0 AUXILIARY FEED; \\TF.R 30 69-1103003-00 FICL"'.E G PRESSU'IICR LE'EI. VS TD'E - CLASS 3 BREAKS ;-!/O AUXILIARY FEEDitATER 31 69-1106003-00 APPENDIX A INADEQUATE CORE COOLING - DESCRIPTION OF PLANT Si!!!AVIOR 32 69-1106003-00 2.0 LOSS 07 RCS INVENTORY WITH REACTOR CCOLANT PtriPS OPERATING 32 69-1106003-00 33 69-1106003-00 3.0 LOSS OF RCS INVENTORY WITHOUT REACTOR 8 COOLANT PUMPS OPERATING 33 69-1106003-00 34 69-1106003-00 4.0 INADEQUATE CORE C00 LING'RESULTING FROM LOSS OF STEAM GENERATOR HEAT SINK 35 69-1106003-00 s
T20131 s
DATE:
11-20-79 PAGE 3-1
+
r - 1 m
r r
^
.. _ ~..... ~....... ~.
e
(
3' N?-20007 (6-76)
SABCOCK & WILCCX u..t.
Nuct.44 Pcwit GEN EAAf;cm avtsicN TECHNICAL. 00CUMENT.
69-1106c03-00 PAPT I - OPERAT!NG GUIOELINES FCR SSMLL EREAKS
- 0 SWPTC5'S AW INDIGTICNS (I1 MEDIATE INDICATICNS) 1.1 Excessive, reae:c: coolant syste= (RCS) =ak eup -
1.2 Decreasing RCS pressure 1.3 Reac:c: trip 1.4 Decreasing pressuri:e: level
- 1.5 ESFAS actuatien*
1.6 Lew makeup tank level' i
1.7 Additional criteria during hestup and ecoldewn*
1.7.1 RCS te=perature increasing, mini =t=2 letdown and pressuri:e level
~
dec:essi=g.
1.7.2 With a ecoldewn of < 100*F/h: and cannot saintain level in makeup tank.
2.0 I. W Id*i ACT!CNS 2.1 If the 25FAS has been initiated aute=atically because of Icw.RC pres-sure, i:=ediately secure. all RC pt=ps.
2.2 Verify centrol recs indications support the ala=s received, verify au:=atic actions, and car:y cut standar:i post-trip actiens.
2.3 Balance high-pressure injection (HPI) flew between injection lines when HPI is initiated per 3.13.
2.4 Verify that app:cyria:e ence-th:cugh steam generator CCT5G) level is maintained by feedwater centrol (by ICS cent:cl ci main feedware: or a,pyriate level cent:ci cf auxiliary feedwater).
2.5 Menitor system pressure and temperature. If saturated condi:icns occur, initiate HPI.
2.6 If ESFAS has been bypassed due to hescup or ecoldewn, initiate safety injectica.
o CALTICN:,
TS 50 subecoling criteria is =et, *:.5:et:1e HPI ficw e
' to keep systes pressure within no=al technical speci-ficatica P-T curve limits. If RC3 is =c 50CF subecoled, centinue full safety injection until 50 F subccoling is C
attained or the P-T limits of Figure 1 are reached.
'May not occur on all s=all breaks.
i T20132 DATE:
11-20-79 PAGE 4
)
e s
' 1, 3'*NP-20007 (6-76)
\\
BABCCCX & WILCOX
. 224 Muc'.t.44 Powet otNitat;CN sivi$1oM 69-110600 00 2-TECHNICAL. DOCllMENT l
3.0 PRECAUTICNS 3.1 If :he ESFAS has been ini:iated on low RC presure, :emination of RC pu._p cperation takes precedence over all other imedia:e actions.
NOTE: If ESFAS has been actuated on high R3 pressure, then conitor RC pressure and trip RC pu=ps once pressure decreases below the ESFAS icw pressure se: point.
3.2 If ESFAS has been initiated, the RC pu:sp's tripped, and the RCS deter =ined :o be at least 50 F subcooled, the operator should establish, as cuickly as possible if the cause for the depressuri:2-tion is due to either a LOCA or non-LOCA (overcooling) event.
Proceed to step 4.4 for non-LOCA events.
3.3 If :he HPI system has actuated because of low pressure ccnditions, it
=ust re=ain in operation until one of the following criteria is satisfied:
1.
The LPI system is in operation and flowing at a rat'e in excess of 1000 GFM in each line and the situation has been stable for 20 =inutes, or 2.
All hot and cold leg te=peratures,are at least 50 F below the saturation :e=pera:ure for the existing RCS pressure and the action is necessary :o prevent the indicated pressuri:er level fr:s going off-scale high.
0 h -: If 50 F subccoling cannot be maintained, the HPI shall be reactivated.
NOTE: The degree of subcooling beyond 50 F and the length of ti=e HPI is in operation shall be limited by the pressure /
temperature censiderations for the vessel integrity (see Section 3.4).
3.4 When :he reactor c:olan: is > 50 ? subcooled, the reactor vessel downceser pressure / tempera: Te (P-T) c:=bination shall be kept below and to the right of the limit curve shown in Figure 1.
The downecmer temperature shall be determined as follows:
3.4.1 With one or more RC pumps operating use any cold leg RTD as an indica-tien of reactor vessel downcomer temperature.
T20133 DATE:
11-20-79 PAGE 5
i j
s l
3'4 ?-20007 (6-76) j l
1
~
SASCOCX & WILCOX suu t t, NuctAt PoWit etNilAfloN =m11oM 6
5' TECHNICAL. DOCUMENT l
3.4.2 With no RC pumps operating the RV downconer te=perature shall be determined by averaging :he five lowest incere ther=ccouple temperature readings and subtracting 150*F from the average incore thermocouple te=perature value.
5 IT.-
U
^
DWN =.
- 150 F T
a where TDWN = average RV dcwnce=er te=perature, F 5
IT,, = sum of the 5 lowest incore thermoccuple te=perature
^
readings.
hvis: Figure 1 is applicable only under LOCA conditions. The P/T curve in the technical specification'is valid for all other operating ccnditions.
NOTE: When the reactor coolant is less than 50 p subecoled, the reactor vessel downcomer pressure temperature ec=bination will inherently be below and to the right of the limit curve.
Therefore, no operator action will be recuired to prevent exceeding the reactor vessel integrity limits until after 0
a > 50 F subecoled margin exists.
Nure: When the reactor coolant is > 50 F subcooled, RC pressure can be reduced by reducing tee HPI flow rate to avoid exceeding the RV integrity limits.
3.3 Pressuri:er level. =ay be increasing due to RCS reaching saturated conditions or a break on top of the pressuri:er.
3.6 If high activity is detected in a steam generator, isolate the leaking generator. It is recommended that both steam generators not be isolated'.
3.7 Other indications which can confirm the existence of a LCCA:
3.7.L RC drain tank (c,uench tank) pressure (rupture disk may be bicwn).
?
3.7.2 Increasing reactor building sump level.
3.7.3 Increasing reactor building temperature.
- 3. 7. 4 Increasing reactor building pressure.
T20134 3.7.5 Increasing radiation monitor readings inside contairment.
3.7.6 Reactor c:olant system temperature beccming saturated relative to the RCS pressure.
UATE:
PAGE 6
i i
e
's s,
s s
ya;?-2CC07 (5-76)
BABCCCX & WILCOX suuen sucua powet casuanc~ :ms:en 69-1106003-00 TECHNICAL. 00CllMENT 3.7.7 Hot leg te=pera:=e equals er exceeds pressuri:er te=perature.
3.7.3 Increase in the execre neutren detector indica:icas.
NOTE: In conjunction with the indications in 3.10.1, this could he an indica:icn of inadequate core cooling.
3.3 HPI cooling require =ents ceuld deplete the borated water storage :ank, and initiation of LP1 ficw from the reactor building st=p to the HPI pu=ps would be required.
3.9 Alternate instru.=ent channels shculd be checked as available to cenfirs key para =eter readings (i.e., syste= te=peratures, pressures and pressuri:er level).
3.10 Maintain a te=peratr e versus time plot and a corresponding te=perature pressure plot en a saturation diagrs=. Using ho: leg RTD's and highest incere ther:occuple reading, these plots will =ake it possible :o ::ack the plant's condition through plant cooldown.
3.10.1 If either of the following indicati=ns of inadequa:e core cooling exist, go to Section 4.3.
1.
Hot leg RTDs read sdperheated for the existing RCS pressure.
2.
Incore ther=ccouple te=pera:=e reads superheated for the existing RCS pressure.
3.10.2 If pri=ary tempera =e and pressure indications correspond to sat =sted coolant conditicas prior :o er during plant ecold:wn, a ret =n to subcooled coolant condi: ions =ay occur.
3.11 Cc=penent c:oling water (CCW) and seal injectf en should be =aintained to the RC pu=ps to insure continued service or the ability :o restart the pt=ps at a later ti=e.
3.11.1 Nor=al li=its and precautions apply for RC m operation.
3.11.2 If the RC pu=ps are tripped for any reason, seal injection shculd be =aintained to ensure long ter:2 seal integrity.
3.12 If RCS pressure increases above the shutoff head of the HPI pu=ps, the MU syste= should be utilized and centro 11ed per Section 3.3.
3.1.T If action is necessary to balance HPI f1cw, then the following steps shculd be taken:
1.
If both HPI trains are available, balance flow between lines in each train.
2.
If only one HPI train is available, throttle the high flew line dcwn to but not belew Figure 2.
T20135 DATE:
11-20-79 7
3WP-20007 (6-76)
BABCOCK & WILCOX Numu NuctAa 7Cwit otNEAAnCM QtVl$ ion es-11cecos TECHNICAL 00C'JMENT l
3.14 If action is necessary to balance LPI flow, then the following steps r
I should be taken:
l 1.
If both LPI trains are available, throttle the control valves as necessary to prevent pu=p runout, per plant limits and precautions.
2.
If only one LPI train is available, open the LPI cross-connec and balance flows. Throttle the control valves as necessary to prevent pu=p runout, per plant limits and precautions.
4.0 FOLLChUP ACTICNS 4.1 Identification and Early Control 4.1.1 If HPI has initiated because cf low pressure, control HPI in
~
accordance with step 3.3.
4.1.2 If both HPI trains have not actuated on ESFAS signal, star: second HPI train if possible. Salance HPI flows.
4.1.3 If RC pressure decreases cen:inuously, verify that core flood tanks (CFTsl and low pressure injection (LPI) have actuated as needed, and balance LPI.
4.1.4 If cause for cooldown/depressuri:stion is detemined to be due to a non-LCCA overcooling event and the RCS is at least 50 F subccoled then proceed to section 4.4 4.1.5 Atte=pt to locate and isolate leak if possible. Letdown was isolated in step 2.2.
Other isolatable leaks are PCRV (close block valve) and between valves in spray line (close spray and block valve).
4.1.6 Determine availability of reactor coolant pu=ps (RCPs) and =ain and auxiliary feedwa:er systems.
If feedwater is not available, go to 4.2.
If feedwater is available, go to 4.3.
4.2 Actions if Feedwater is not Available 4.2.1 Throughout the follow g steps maintain =2xi=um HPI flow and restore feedwater as soon as possible. The electric startup feed-water pump is an alternate scur:e of feedwater, and shcuid be aligned and started as soon as possible.
4.2.1.1 If ESFAS has actuated due to low pressure, maintain steam generator r
1evel at 96 inches on the SU range instru=entation. If low pressure ESFAS has not actuated sain: sin level at greater than 35 inches.
4.2.2 If RCPs are operating, go to one pu=p per loop. If RCPs are not operating, go to step 4.2.3 below.
4.2.3 If RCS pressure increases above the HPI shutoff head, open PCRV and leave open: align / actuate MJ system per 3.12 and control per HPI instructions given in 3.3.
DATE:
PAGE 11-20-79 3
T201:36
. _ _. _. _.. _...... ~..._ -_.-
.--....._.e t
4 3WP-20007 (6-76)
BA3 COCK & WILCOX sua m sucua rowns ci.uAnen ems:c*
59-1106003-00 TECHNICAL DOCUMENT NCTE: If the PCRV canno: be actuated, :ne safeties will relieve pressure.
4.2.4 When auxiliary feedwa:e: is rec vered, restore CTSG 1evels in a centro 11ed =anner and establish app cpriate CTSG 1evel cent:cl.
Secure electric Su-74 pu=p if cpers:ing and close NRV or block valve, if possible. P: ceed to step 4.3.2.
4.2.5 If no RCPs are operating,' epen PCRV, =aintain HPI flow, and align / actuate MJ syste=.;e: 3.12.
NCTE: If the PCAV cannot be actua:ed, :ne safeties will relieve pressu:e.
4.2.6 When auxiliary feedwater ficw is restored, resu=e autematic CTSG 1evel c:ntrol at 96-inches indicated en the SU-range inst:n=entatica and close PCRV or block valve, if possible.
4.2.7 Verify natural ciretlation in the RCS by cbse:ving:
4.2.7.1 Cold let te=perature is saturatien te=perature ci sec..-dary side pressure within app:cxi=ately 5 minutes.
4.2.7.2 Pri=ary AT (~ECT-TCOI.D) bec =es c nstant.
4.2.3 Go to step 4.3.4.1.
4.3 Actiens with Feedwater Available to One or 3oth Ceners:::s 4.3.1 Raintain ene RCP : :nning per 10cp (s:cp other RCPs). If no RCPs operating (due to a loss of offsite power or due to manual securement per Sectica 2.0), go to step 4.3.4 below.
4.3.2 Allow RCS pressure to stabill:e.
4.3.3 Establish and =aintain OTSG c:oling by adjusting stea;.: pressure via turbine bypass and/or a:=cspheric d==ps.
Cooldewn c.t 100 F per hcur to achieve an RC pressure of 250 psig. Refer :o pre-cantien 3.10 fer development of temperature and pressure plo:s.
Isolate core fleed tanks when 30 7 sube:oling is at:alned and RC pressure is less than 700 PSIG. Go into LPI c:olin; per Appendix A.
4.3.4 If RCPs are not cperating:
4.3.4.1 Ye nfy stes: generato: level centrol a: app cpriate setpoint and verify the cenditic=s in step 4.2.7.
T T20137 DATE:
11-20-79 PAGE 9
66 94N"'
'*-M#9*N 8
e es g...et.em g o.
e..
&* eie 4"
- .6 N h
.gr.
ey e*
_to.
em N 8."
h-WW e
- 3 w
p._.
7,,,_.~
p
-,,s
's '
3'4i?-20007 (6-76) 3ASCOCK & WIiCOX sum.
NuCL144 Powlt otNE.tAffoN em34cM 69-060o3-00 TECHNICAL DOCUMENT 4.3.4.2 If RC pressure-is decreasing, wait until it stabili:es or begins increasing. If it begins increasing, go to step 4.3.4.4 4.3.4.3 Proceed with a centrolled cooldown at 100 F/hr by controlling stea:
generator secendary side pressure. Monitor RC pressures and te=pera.
tures during cooldown and proceed as indicated below:
4.3.4.3.1 If RC pressure centinues to decrease, following secondary side pressure decreases and'with primary system te=peratures indicating saturated conditions, continue cooldown until an RC pressure of 150 psi is reached, and proceed to step A.4 of Appendix A.
4.3.4.3.2 If RC pressure stops decreasing in response to secondary side pressure decrease and reactor syste= becc=es subcooled, check to see that the follcwing conditions are both satisfied:
A) All hot and cold leg te=peratures are below the saturation te=perature for the' existing RCS pressure.
and
- 3) The het and cold leg te=peratures are decreasing in response to steam generator secondary te=perature decrease.
If these conditions are satisfied and re=ain satisfied, g:n:inue cooldewn to achieve an RCS te=perature (cold leg) of 230 F, and pro-ceed to step A.1 of Appendix A.
NCTE: If the conditions above are =et beicw 700 PSIG, the core flood tanks should be isolated.
NOTE: If the pri=ary syste= is 50 F subecoled in both hot and cold legs and pri=ary syste= pressure is above 250 PSIG, starting a reactor coolant p *F subcooling in two minutes, trip m s.
is per=issible. If systes does not return to at least 50 If forced circulation is achieved, preceed to step 4.3.
4.3.4.3.3 If RC pressure steps decreasing and the conditions of 4.3.4.3.2 are no: set or cease to be set or if RC pressure begins to increase, then proceed to step 4.3.4.4 below.
4.3.4.4 Restore RCP ficw (one per loop) when possible per the instructions below. If RC pu=ps cannot be Operated and pressure is increasing, go to step 4.3.4.6.
4.3.4.4.1 If pressure is increasing, starting a pu=p is permissible at RC pressure greater :han 1600 pSIG.
T20138 DATE:
11-20-79 PAGE 10 e
~~
sg' a
3'.NP-20007 (5-76)
BABCOCK & WILCOX e us sucma mwas casuanom : msec" 69-1106003-00 TECHNICAL 00CljMENT 4.3.4.4.2 If reactor ecolant systen pressure exceeds steam generator secondary pressure by 600 PSIG or = ore "btc:p" one reactor coolant pu=p for a period of approxt=ately 10 seconds (preferably in operable stes=
generator loop). Allow reactor coolant system pressure to stabilize.
Continue cooldown. If reactor coolant system pressure again exceeds secondary pressure by 600 psi, wait at least 15 minutes and repeat the pump " bump".
Bu=p alternate pe=ps so that no pe=p is b= ped
= ore than once in an hour. This may be repea:ed, wi:h an interval c:,
15 =inutes, up to 5 ti=es.
After the fifth "bu=p", allow the reactor coolant pu=p to continue in operation.
4.3.4.4.3 If pressure has stabili:ed for greater than one hour, secondary pressure is less than 100 PSIG and primary pressure is greater than 250 PSIG, bu=p a pu=p, wai: 30 sinutes, and start an alternate pu=p.
4.3.4.5 If forced ficw is established, go to step 4.3.3.
4.3.4.6 If a reactor coolant pu. p cannot be operated and reactor coolant systes pressure reaches 2300 PSIG, cpen pressuri:er PCRV to reduce reactor coolant systes pressure. Reclose PCRV when RCS pressure falls to 100 psi above the secondary pressure. Repeat if necessary. If'PCRV is not cperable, pressuri:er safety valves will relieve overpressure.
4.3.4.7 Maintain RC pressure as indicated in 4.3.4.6 if pressure increases.
Maintain this cooling sede until an RC pu.'p is started or steam generator cooling is established as indicated by establishing con-diciens described in 4.3.4.3.1 or 4.3.4.3.2.
When this occurs, proceed as. directed in those steps. Go to step 4.3.2 if forced flow is established.
4.4 Non-LCCA Overcooling Transien; with Feedwater Available 4.4.1 Immediately restart a RC m in each locp if the RCS is 50 F subcooled.
4.4.2 Control steam pressure via turbine bypass or atmospheric du=p valves to stabili:e or cont cl plant hea: p.
NOTE: Considerable HPI :nay have been added to the RCS. Therefore, to prevent RCS frem going solid, the above action =ay be necessary.
4.4.3 As long as the RCS is =aintained 50 F subcooled, throttle HPI/MU and letdown ficw to =aintain pressuri:er level at s.100 inches.
- 4. 4. 4.
Using turbine bypass valves and feedwater system, control steam generators as needed to lisi: plan: heatup until RC pressure control can be re-established with the pressuri:er.
NOTE: Cold RCS water =ay have been added to 'the pressuri:er; there-fore, a period of ti=e =ay elapse before nor=al RC pressure control can be established with the pressuri:er heaters.
T20139 DATE:
11-20-79 PAGE 11
S gs 3's ?-20007 (6-76)
BA3COCX & Wit.COX Nu. o NUCL!.At PewH GINDAT:CN OlVi$iCN TECHNICAL. DOCUMENT 4.4.5 Cnce pressure centrol is re-established, u;e ac=al hea:up/c:cidewn procedure to establish desired plant c:ndi:icns.
4.5 Actiens for Inadecuate C re Cooling 4.5.1 I=ediate steps for inadequate core cooling NOTE: If RC pu=ps are : :nning, do not ::ip pu=ps.
This super:edes inst:uctions in section 2.1.
4.5.1.1 Verify HPI systen are E:n::icning properly with maxi. us flew. St ar
=akeup pt=p(s), if possible, to increase injection flew.
4.5.1.2 Verify stem generator level is being controlled at 95's on cperate range.
NOTE: Fc TECo ste n generato: level should be at 96 inches indicated en the startup range.
CATICN: Reference leg boiling could give false level indicati:n.
4.5.1.3 Depressuri:e cperative stem genera:c:Cs) to establish a 100 F/h:
0 dec sase in sec=nda:y saturation te=pera:ure.
4.5.1.4 Ensure core fleed tank isciation valves are open and tha LPI actua:es if pressure reaches 420 psi.
4.5.1.5 If reae:cr c olant syste= pressure increases to 2500 PSIG (1500 PSIG for DB-1) cpen pressuri:e PCRV to reduce reactor coolan systes pressure. Reclose PCRV when PCS falls :o 100 PSIG abeve the see ndary Pressure. Repeat if necessary. If PCRV is not cperabic, pressuri:e safety valves will relieve pressure.
4.5.1.6 P ceed i=ediately :.: 4.5.2.
4.5.2
'dhen the indicated incere the=cccuple te=peratures c: het leg RID temperatures are superheated fer the existing RCS pressure, cperator action shall be based en c nditions dete=ined f::m Figure 3, by a sample of the highest incere the=cccuple temperature readings to dete=nine the core exi: the=ccouple te=perature.
NOTE: More than ene the=oc:uple :e=perature reading should be used (for example use the average of 5).
4.5.3
'dhen the incere the=cccuple te=perature has been dete=ined per Sectica 4.5.2, go to the section indicated belcw.
T20140 DATE:
11.gg.79 PAGE g;
- 4See O
___,__e
\\
3',i:.7-IO007 (6-76) 1 BABCOCX & WILCOX uuun l
sucma rewn ce.uar:cu ms: "
.59-1106003 00 TECHNICAL. 00Cl] MENT Incore Ther:ccoucle Te=rerature Section Incore Tc 1 Saturation 4.1.6 Carte 11 Incore Tc < Curve 2 Figure 3 4.5.4 j
Incore Tc > Curve 2 Figure 3 4.5.5 NOTE: The incore ther=occuule :emperatre readings shall be continuously monitored until the indicated incore thermo-couple tempera:=es return to saturation :e pers:=e for the existing RCS pressure.
4.5.4 Actions for curys 11 Incore Tc < Curve 2 Figure 3 4.5.4.1 If RC pucps are not operating, start ene pu=p per loop (if possible).
This instruction supersedes previous instructions to trip RC pu=ps.
NOTE: Do not bypass nor=al interlocks.
4.5.4.2 Depressurizer operative steam generator (s) as rapidly as possible to 400 PSIG or as far as necessary to achieve a 100*F decrease in secondary saturation temperature.
4.5.4.3 Open the FCRY, as necessary, to maintain RCS pressure within 50 psi of steam generator secondary side pressure.
NOTE: If steam generator depressuri:aticn was not possible, open FCRV and leave open.
4.5.4.4 I=:ediately continue plant cooldewn by =aintaining 100 F/hr.
Decrease in secondary saturation te=perature to achieve 150 PSIG RCS pressure.
CAleTICN: If auxiliary feed pt:=p 'is supplied by =ain steas, do not decrease pressure belcw 50 psia for auxiliary feed pu_7 operation.
4.5.4.5 If the average incere ther=occuple temperature increases to Curve 2 Figure 3 proceed is=ediately to Section 4.5.5.
4.5.4.6 When RCS pressure reaches,150 PSIG, go to Appendix "A".
4.5.5 Actiens for Incore Tc > Curve 2 Figure 3 4.5.3.1 If possible, start all RC p eps.
NOTE: Starting interlocks should be defeated if necessa.y, but in order to sinisi:e the possibili:7 of a fire due to bypassing seme interlocks, the fo11cwing precautions shculd be obser/ed:
- 1) Do not defea: the overload trip circuit and 2) if CCW is not restored to the =ctor within 30 minutes, trip the RC pt=p.
T20141 DATE:
11-20 ~9 EAGE 13
. l
_w,
.m
's \\
3'a?-20007 (6-76)
S A3 COCK & WILCOX
,.um Nucu.AA PCwit CINERADCN Om$ ION 69-110600,-00 2
TECHNICAL DOCUMENT I: should b'e reccgni:ed : hat starting the RC pu=ps without ecoling and/or injection water will p:cbably fail the pump seals and say cause the pu=p shai: :o break. How-ever, sc=e core cooling will be p;cvided prio: to dest:ucticn ci the pump. Breakage cf the pu=p shaf: shculd not caus e censequential da= age cu: side of the pump.
4.5.5.2 Depressuri:e the operative steam generator (s) as quickly as possible to between 30 to 75 psia.
CAUTICN: If auxiliary fee,d pu=p is supplied by main ste::m, do not decrease pressure belew 50 psia or stea= driven auxilia:y feedwater pu=p will not deliver wate: to the stea= generators.
-4.5.5.3 Cpen the pressurizer PCRV and leave cpen.
NCTE: The RCS will depressuri:e and the LPI systes should restore core cooling.
4.5.5.4 When incere the:=occuple te=peratures retu:n to the sa:dratien ta=perature ic: the existing RCS pressure; and the LPI syste= is delivering flow, p:cceed as felicws:
4.5.5.4.1 Cicse the pressuri:e: PCTsV; reopen if RCS pressure increases abeve 150 PSIG.
4.5.5.4.2 Decrease to two (2) AC pu=p cperatien (ene per Icep).
4.5.5.4.3 Isolate the core ficod tanks.
4.5.5.4.4 Maintain steam generato: pressure-between 50 and 75 psia. Do not icwer belew 50 psia for auxiliary feed pu=p operation.
4.5.5.4.5 Cent:ci HPI per 3.5.
4.5.5.4.6 3!cniter 3* DST level as ic-lo level li=its are app cached, align LPI system fer suctica frem RB su=p.
C1cse the LPI 3NST suctica valves.
NOTE: If HPI is recuired per 3.3, align LPI and HPI in piggyback mode. Shut off mini =um recirculatica lines to SWST.
CAUTICN: Do not deadhead HPI pu=ps when =i.'i-m recirculation lines are closed. This may damage pu=ps.
~
4.5.5.4.7 Go to Appendix "A".
T20142 11-20-79 DATE:
pggg 14
~
~
~
. ~.
N 1 k*
e.
3*A7-20007 (5-76)
SABCOCK & WILCOX
,,y.. n sucu4a rown ce.uance. emsson TECHNICAL DOCUMENT 69-tt06003-c0 APPENDIX A LPI CCOLING A.1 Dete$::ine if pri=ary coolan: is at least 50 F subecoled. If not, go to step A.3.
A.1.1 Star LPI pu :ps.
If both pu=ps are operable, go to step A.2.
For one LPI pu=p operable =aintain OTSG cooling and proceed as fo11cws.
The operable LPI pu :p will be used to maintain syste= inventory.
A.I.2 Cbtain pri=ary syste= conditions of < 230 F ond < 250 PSIG.
A.1.3 Align the discharge of the operable LPI pu=p to the suctions of the HPI pu=ps and take suction frc= the SWST If the BWST is at the low level alar =, align LPI suction fro = the RS su=p and shu: suction. fro: 3WST.
A.I.4 Start the operable LPI pu=p specified above. The HPI-LPI systems will now be in " piggy back" and HPI flow is maintaining syste pressure.
A.I.S Go to single RC pu=p operation.
A.1.6 Mien the second LPI pu=p is available, align it in the decay hes
= ode and cc==ence decay heat re= oval. (Decay heat syste= flew greater than 1000 GFM). Secure remaining RC pu=p when decay heat re= oval is established.
CAITTICN: Verify that adequate NPSH exists for the decay heat pu=p in the DH re= oval =ede.
If inadequate, transfer to LPI =ede.
A.I.7 Reduce reacter ecolant pressure to 150 PSIG by throttling HPI flow.
Centrol RC te=perature using the decay heat syste= ccoler bypass to
=aintain syste= pressure at least 50 psi above satur:. ion pressure, to assure that NPSH require =ents for the decay heat pu=p are =aintained.
A.1.3 Secure the FPI pu=p and shift the LPI pu=p supplying it to the LPI injection =cde.
A.1.9 Reduce reactor coolant te=perature to 100 F by centrolling the decay heat syste= cooler bypass.
NOTS: If one of the LPI/ decay heat pu=us is lost, return to OTSG cooling using natural circulation br one reactor c= clan: pu=p.
Go to A.1.1.
A.2 Ccoldewn en Two LPI Pu::ms A.2.1 Maintain RCS pressure at < 250 PSIG and reduce RCS te=cerature to
~~
< 230 F.
~
A.2.2 Align one LPI pu=p in the decay heat remov:a1 mode.
DATS:
11-20-79 pAgg 15
-ang
.a
..-~.
- A, M'P-20007 (5-76)
B ABCOCX & Wit.COX Nu su NuCLt.AA powet c(N{#AT!oN OlVI$loN
" -
- 6 5-TECHNICAL DOCUMENT A.2.3 Secure one C pu=p if two are cperating.
A.2.4 Start the decay heat pu=p in the decay heat re=cval = ode, and when decay heat syst.e= ficw is greater than 1000 GPM, sec c e the running RC pu=p.
A.2.5 Reduce RC pressure te 150 'PSIG by throttling HPI flow. Control RC te=perature to =ain: sin 2: less: 50 psi =argin to saturation pressure.
A'.2.6 Star: the second LPI pu=p in the LPI injection =ede.
Secure HPI pu=p.
A.2.7 Shift LPI suction frc= the SWST to the reactor building su...p when sufficient NPSH is available.
NOTE: This is riesirable to avoid unnecessary quanti:les of water in contain=ent.
A.2.3 Reduce reactor coolant te=pera =e to 100 F by controlling the decay heat syste= cooler bypass.
NOTE: If one of :n. LPI/ decay heat pu=ps is lost, return to OTSG cooling usir.; naturs1 circulatica or one RC m. Go to A.1.1.
A.3 Cool Down RC Syste:- at Saturation A.3.1 Maintain RC pressura at < 250 PSIG.
A.3.2 Align ene LPI pu=r to suction of the HPI pumps and the suction to the reac:cr building su=p.
(Shut 3WST suction valve for this pump.)
A.3.3 When the 3h3T level reaches the lo-lo level li=its, start the LPI m and shut the HPI pu=p suction fr== the SWST.
A.3.4 When pri=ary syste= te=perature becc=e4 subcooled by at least 50 F, go to A.1.1.
A.4 Ccoldown withcut Reteter Ceolant Pu=rs A.4.1 RCS initial conditiens are: pressure 150 psi, te=perature at satura-
-tien.
A.4.2
- Align Icw pressure injection syste= for suction frc= reactor building sump and place in.o service, r
A.4.3 Balance LPI injection and control RC te=perature with decay heat coolers.
A.4.4 Isolate core flood -anks.
A.4.5 Go to st.p A.1.1 and follow the precedure given there, ignoring the instructions rela-ing to RC pu=p cperation.
T20144 D/.TE :
11-20-79 PAGE 16
.=
Mw-
,,y 4--+.
-.e-%
.s y
e
---m.
--r g
7
e4 BtC?-20007 (6-70 i
i BABCOCK & WILCOX suusu sucun rewn otruiecr4 omsic,,
Tr on o n..r.sr.a l t,1.L p ihn 2 h !
69-110600a 00
.,. n., -. i J
i c.
i
.. ::...:.... :...]......:. l... l.....
Lj
..n:
.I.
m^
- a
.l l
i:l::'
~
._ t 1:
....!... li
- e.-
o,
e o., o i.I......ir
.e n., s2. < e o o.
...a n
i.
u pb M N Et i
e f')
._.L
.i l
-i...
N"
- t m m l
t.
i
.1 :-
a I
' i' o
I
..g.
...
- I..e
.i. l -
eC,,,
C c..o.c o.o o m
. }c i-c o
l c*
~.oaNN u
4
..I..
Sie i
W
- x: I t_
n
.l.e
. i I q I. \\l. I. - l ali i l " l " l ' :i ~ l. l I ~l: Is' I i
N "E
i f
-oo
. l " (" l. :1.
l :-i.-
" t i'.
.m u o
.. t..
[" ji t ::i: : ;
- $::n.:. i.:l :i i ::$:: i.
3
- $ $ D Fl l
- "li: I: l' I : b.
4:-si Mi i ML '
h l ' !"; l l'
! : "l" -E l
- l -*i l l 'i l w.$-5 l
l' i'nt :t""l
! - l
- ! i'.
,o2 o-=
t.:i l
. ! ~ j ;. _l :.l".l ; $ :
- t. j.i
.i w uo l:
l
(+-6:-
ou:
__ ' l:.."' l.::.i:..l - ' :
i;!:"t' __
,=
- li
- : j :
- p.
- - l. ' :.l.. *
$ <,8
. [.
P.. l ;i l.'
" $=
I, *
! l :t: :l a:;:"..l..
- .1.. a i.t..
i.:
. h.
4 i J. u. :. j +. l 'ne".. l. j :
.s y
3g3 i
<i" p ; 'j. it: j- :l: ;.:i-l
- j
- l::
- ia j: - p "! ~ ~j:
j g
3
~Z2
[- - - -- l. 4 : l. i'.:4. ii.. l.::nj -
).N l.
l
..i.... j, !. t
- Y, ooo l-
.l
. l.; - l.-
l"
. : u. l.. :l
.l-I.
. D :.
.,a w a c.
n x
o c
o o o 'u
- :l
'-[
- [:
i i..
..j.
j j.
i l.
w w.* c s...
..r;. -..
i.*
- i... -
.. o n+
o.,
1-x
- s u
- a a
u a.,
1:
- a o, w:
c.s 7.l -
j.: i". j.:ti:.y :.. :l -
- t.
m s - :.:.
._ U80
~
e n
m3 a n :a u
e i -
.. r.u.+
. i,
- i. s.
.c
.. a u
aa
""" E38 l
nW 3
4J M
- c. Et 3 -
3*-l I.-
u i
. ?
"h
'4 9 W O
.I,h. e d,
.lu. l
- l.
l ' I l~
., l ~
5h
..z s.
- c. s a.*
e 3
c t
I e
i m
0 w e (J
..g
...I.
l g
3' t. u o
58
't A d -- - :,!
l,.,'.
Q.w
.1 i
- i u
am.
- s u.=
o
u
.)
-l gj W Cd f3
$ g *' "I ;.j..
.l-I.:t:ri-l.
.. l :-
-.g
..g..".-
. I:. :
t.
(J u
%. c se s j.
6 t.3.m o-e
. i l
. g +"
.l l-4.:.
O r3 8.s t
g g a
u-
.n, g g.....
M
.j *w =-
coa =.
l u
n.=
-. u -.
W j
ou os<
t i iaq l
- < i t 3Ji.
- p. n.
ts
- a.-
1 i (
6 oQ
.=.
2 d.-e O
u r..
_- -..i u.,
3
..f....
C w a.*
4 e
,-*-,.a.
c uu u
2..
3 l
= !.; t -
4
-l
- . I i
-ibu l. '
.e :
o o
22 i
I
- Wl.. ; }-
l l
r: i:.
~
g,, g j
P-
-j-l-
-l.
- je ;.l l, J
- . p-i g
[.... l "..
t-l.
II I-N;iil ' i'" l l i la!n~l J P l~ "iurl.:: l !_
_i
. l":!.uf +-]_n i:-
n : i l t.- l
- l : l.:l..
"inhl.
?
3 o
o o
o o
o o
o o
o o
.o
.oe e
e o
e N
N a
STsd 'oanss324 tueTeoo :c:scay anc.sotty ::r:::;:mg Tood.d.5 D ATF. :
11-20-79 pAcg 16-1 4
j
% NP-20007 (6-N BADCOCK & WILCOX man mm rown cien: 4 :msion r1 m e e 69-1106003-00
" r..n a. t e. !. *.ri.a.
- A:m. s.
e t =1
)
4 e a w..
- v..
Figure.2 Mir.imum Required IIPI Flow vs. RCS Pressure
,. i- >
....o
.i:....
K00 -- ~..,.
- - - ~ ~ - - - '
.L.,.
.l..:,a
- 1 L. 3
,l-
"I
,:. Eb.
'* - - g"~.
. ;;= - -- :
4....g. *
"..r.
.e:
... =. --...-..
2.
..t..
.-*-...t. :........ ~.... -
.........l...
^^
, g,;
.-~
[.
b -
.t..
. a. -.. :'-- :.. : g-
. j :. -
1400 --..:
r
.:1..
.-..:"..........1.*
..2".**g.."
..,.....s
~
. *.. :.;. _ :=
. "g'.-.
- .t.
.: L
.. - i:.i n:
l
.....a. 1 r..d... :. !..:.
....... n..r.
M. n....'.d
.. t i. t'. :
u
- ..:: p.t..
g.
- n n. e u n f. r.n. r. :.:.
a. ::.
..t..
1200
. a.- m...c. c.:....
...... r.. l;.
~.2. : i, u.
- . n....
.. n..'...r. : t :. l.:...... :dr:..:
r.
- r-
. j..
u..l : ::..n \\.r::: :
=-- &:.u:.:..
-. l - ta
- c-un..s.. -
- ...r
- c. :.
_._.1
. _l s.
.nrn rIn: _
..i...::. n. ::.. :
1... b..n.:.e
- r. i.. l a.
n..
..,"...........r:
...e Tr:::
8~
- ..... ~... l.... l.. - : l... p...
..s...
s.
.....w._
. f.......p:...l 7
~
,..t 10 0 it... a-*. i%..'..*;i:iw.EI* l*N:.! : i I Efi,.. blis d
.- - n.-.- :l ni: : :- : g - s=. :.,=.r ::n:t-- :. [..
o.
- r;-.
...". -lu._ :.:
- p: u.;. :.. n. : p. ::.:.,.,..
n
.g.
D 5.M....i l.# W"l E I. 25i!..:d I.9 4.~ i."*.:i
- d.N.8d...i.ii.i.d.
r: :.,l. --.
. -....-.:..a. ;:. :: r_.r. ;... a...
. g
... l:.
r:
.,. p ;..:.
h 800 r-.
-- - - - - - - -.;, q
..._.. :: r. ' n....;: l........ -..
.m.
... p:t.:: r_ h...
._:g. n..... 5:
,n,
. :;:. :-.n.. a. e c.... --...
- :- :- r -. :. : = = l:.....,:..... i.. \\. 8.: :u. :
r
.2 :..
- u..:.::1.:
, : - n..-
- n. ::.:.:.-. \\..
r
.=.._:::
- 4...-
n.
.. n.:.~L.... :. nn.; -
.r - -. " - r a :..
. :.... : ~...... ::....... n. :
- a. i... :. r.
.......a. :. :... :: r.. n_. r............ -.....- :.
- n. : :
- - n-t- - "..
,7-
- -.,.... y z- :..- t -
000
-.c n:2.;::.... l. ::...:. :.._.: u_m_.i n.. e - "
a_. c
- n. : i. m:.:
--- \\. n.;;..: -
- .-... e_r _..- ::
- :- :r: r:n-.. c-r:::
=;2a-_l a... :.:..p. +--.. l :.m.. - j
..n =.. :;b. -n..u.. ;.-.
E re _ ::.- r. : : -- r
. n r-- :.: n.
_- t.-. ls. ;.. s.m"'! n.:.. n:::r j :. 8:.::.h. n.a. rj-
..r :*,t *..
- 2. f
- a..
2
- n. 2.L-~. :n.r ": ~j?
T - :" f-- ~- :...... :.-*; :
g*
. 2 ;!:;" t ** 0.. f.-
n P..}.......l". :::.-.:;- * *:
?: P T : -'"_.. I.... I:.
- 2.. ;t.",:,. r. ;,.,;... : ;.t. r.
-":=..........:-n.:r. ::r. ;.:. :. :..:.:..w: n
- 4'r..:s.v.. n:u.(... B..: t.
r j. s ". 3,.....?.
n..
....I.
r f*. :*
- .g g... g:..' r".'.".
. ". l...r....... * * * - -.
..,4.
s 4
........l..
g.
9 C ~a.p;...
- .l.-
- " " ~ ;- : ::
o g-- -
4.
..I.
.".'-...l..g.....:.....".l........
.... 8 7.
- :... t.; ;. )
p
..7.
d=
.... [.=. -. l.. \\..
- ..n
.......g...
- e. _::.:p:r w..... :
......n : :.... :: -
- .u:1.r... : :n_--.........
-in::;r
.e ::: -.
c~:.n -
ne'
.. ;.. : i.....u-
- n. [ n. 3n
..,.n t y : 7p...
.:n;..a:.e.ln.... -.
".a.;.
..po-p-
..i :
.y*
. y g.... g..
s.
,..l :
H.;. t g:....g : : -.
f: ' * ::.
8.1'.. -..." "... l".
l ~ l......, i.
...: I:-
n.
=.=.
8...
- l..-
' g "--
~-
r
- j~ '... ~ ~ " ' -
0 u._.
a.
..~.4.....;
.. a
....,.ca-......
0 100 200 200 t,00
!!rl Flow (Or:!)
T2^1 M DATE: 20-79 PAGE 16-2
.a.-...........-....-.
D'.:::F-2000 7 (6-76)
BASCOCK & WitCOX NUNJ t 3 NUC'.! A2 70'.wt2 CLN t2AliCN OtV!$ ION r
69-1106003-00 J:a.r t". l.".9. [.h.;) p,'i n e'H' I um -;.
... L.. i t.
Figure 3 Core Exit Thermoccuple Temperature for Inadequate Core Ccoling 12:3 11C3 Ctavt v2
=
1 3.a TCLAD LESS T m 1:02*;
3 1000
.-2 3
3 SC3 c
/
s
=
/
/
E03
/
Ct.7.YE il 2
/
/
O Tgtg L2II i::Js i4:c*r 7:3 603 -
-j sac 1
403 2C3 603 1033 1433 13C3 2:33 Pr:ssure. ;iss.1 T20147 s
DATE:
11-20-79 PAGE 16-3 g
h
.D.W 4
p
+ - -
+e-
...~. _ -....-.-.-.~.--_......
3WP-20007 (6 =-75)
SABCOCK & WILCOX we acwa scwti ci uaos oms' "
o9-1105003-C0 TECHNICAL. DOCUMENT PART II: SMALL 3REAK PH.ENCSENA - DESCRI?TICN CF PLANT 3EFX/ICR 1*0 INTROCUCTICN A less-of-coolant accident is a condition in which liquid inventory is lost frem the reactor coolant system. Due to the loss of mass frem the reactor coolant system, the =os: significant short-term symptom of a less-of-ccolan: accident is an uncontrolled reduction in the reactor coolant system pressure. The reactor protec icn system is designed to trip the reactor on low pressure. This.should occur before the reactor coolant system reaches saturation conditiens.
The existence of saturated conditions within the reactor system is the principal longer-term indication of a LCCA and requires special consideration in the development of operating precedures.
Following a reac:cr trip, it is necessary to re=ove decay heat frem the reactor core to prevent da= age. However, so long as the reactor core is kept covered with cooling water, core damage will be avoided. The ECCS systems are designed to respond auto =a:ically to low reactor coolant pressure conditiens and take the initial actions to protect the reactor core. They are si:ed :o provide sufficisnt water to keep the reactor core covered even with a single failure in the ECCS systems. Subsequent operator actions are required ulti=ately to place the plant in a long-te:m cooling =cde.
The overall objective of the au:cmatic emergency core ecoling system and the follewup operator :.criens is to keep the reactor core cool.
A detailed discussicn of the small break LCCA phencmenalogy is pre-sented in this sectien. This discussien represents Part II of the operating precedure guidelines fer the development of de:siled eperating precedures. Part I presents the = ore detailed step-by-step guidelines.
The response of the pri=ary system to a small break will greatly depend on break si:e, its location in the systen, operation of the reacter ecolant pu=ps, the nder of ECCS trains functioning, and the availability of secondary side ecoling. RCS pressure and pressuri:er level histories for various ccmbinations of parameters are presented in order to indicate the wide range of system behavior which can occur for small LCCA's.
2.0 IMPACT CF RC PDiP CPERATICN CN A SMALL LCCA With the RC pumps operating during a scall break, de steam and water will remain mixed dt ring the ::ansient. This will result in li uid i
q being discharged cut the break centinucusly. Thus, the fluid in the RCS can evolve to a high void fracticn as shewn in Figure 1.
The maxi =um void fracticn : hat de system evolves :o, and the time 1:
occurs, is dependent on the break si:e and location. Centinued RC pump operation, even at high system void fractiens, will previde sufficient core flow to keep cladding te=perat tres within a few degrees of the saturated fluid temperature.
T20148 D AT*~ ~-
PAGE 11-20-79 17 a
n.
p.e.
9 m-s, Q
sgm.
e w'-
4
- mM
-.--.y mV'~r
'~
3*u?-20007 (5-76)
BABCOCK & WILCOX r.u-s e n
%uc'.!A4 PCwit CINilAf;cN Olvi$icN TECHNICAL DOCUMENT 69-1106o03-00 Since the RCS can evolve to a high void fractien for certain small breaks wi-h :he RC pumps on, a RC pu=p : rip by any means (i.e., loss of offsite power, equip =ent failure, etc.) at a high void fraction during the small break ::ansient =ay lead to inadequate core ecoling. That is, if the RC pu=ps trip at a time period when the syste= void fraction is greater than approxi=ately 70%, a cor hea:up will occur because the a= cunt of water left in the RCS would not be sufficient :o keep the core covered. The cladding te=pera:ure would increase until core cooling is re-established by the ECC syste=s. For certain break si:es and times of RC pu=p trip, acceptable peak cladding te=per-atures during the event could not be assured and the cere could be da= aged. Thus, prompt operator action to trip the RC pu=ps upon receipt of a low pressure ESFAS signal is required in order to ensure that adequate core cooling is provided. Following the RC pump ::ip, the small break ::ansient will evolve as described in the subsequent sections.
3.0 SIALL 3RF_AKS WITH AUXILIARY FEEDWATER
~
There are four basic classes of break response for small breaks with auxiliary feedwater. These are:
1.
LCCA large encugh to depressuri:e the reactor coolant syste:
2.
LCCA which stabili:es a: approximately secondary side pressure 3.
LCCA which =ay repressuri:e in a saturated condition 4
Small LCCA which stabili:es at a primary syste: greater than secondary syste= pressure.
The syste= transients for these breaks are depicted in Figure 2.
3.1 LCCA Large Encuch to Deeressuri:e Resetor Coolant Syste=
Curves 1 and 2 of Figure 2 show the respense of RCS pressure to breaks that are large encugh in ec=bination with the ECCS to de-pressurize the syste= to a stable low pressure. ECCS injection easily exceeds core boil-off and ensures core cooling. Cu:ves 1 and 2 of Figure 3 show the pressuri:er level transient. Rapidly falling pressure causes the hot legs to saturate quickly. Cold leg te=perature reaches saturatica sc=ewha: later as RC pu=ps coast e
down or the RCS depressuri:es below the secondary side saturation pressure. Since these breaks are capable of depressuri:ing the RCS without aid of the steam generators, they are essentially unaffected by the availability of auxiliary feedwater. Ucon receipt of a icw pressure ESFAS signal, the operator must': rip all RC pumps and verify that all ESFAS actions have been ce=pleted.
The operator =ust also verify tha: the HPI ::ain flew is balanced th: ugh each injection line.
T20149 DATE:
11-20-79 PAGE 13
- N
+
e e go q ee e ee se
.m e.eo m.4 m r
-w-
.. _.... ~.... - _. _
3WP-20C07 (6-76) i BABCOCK & WILCOX uuuta muctua rowen castunoN 3M$iCN 69-1106003-00 TECHNICAL. 00Cl] MENT The operator should also balance LPI flows, should :he sys tem be actuated, to ensure flow through both lines. The operator needs to :ake no further actions to bring the system to a safe shu:down condition. Rapid depressuri:ation of the steam generators would only act to accelerate RCS depressuri:stion.
It is, however, not necessary. Restarting of the RC pu=ps is not desirable for this class of break.
Leng-term cooling will require the operator to shift the LPI pu=p suction to the reactor building su=p.
3.2 LCCA which Stabili:es at Aer-eximatelv Secendary Side Pressure Curve 3 of Figure 2 shews the pressure transient for a break which is too s=all in ecmbination with the operating HPI to depressuri:e one RCS. The steam generators are, therefore, necessary to re= eve a portion of core decay heat. Although the system pressure will initially stabilize near the sec ndary side pressure, RCS pressure =sy even:ually begin falling as the decay hea: level decreases. Curve 3 of Figure 3 shews pressuri:er level behavior. The hot leg tempers':ure quickly equalizes to the sat =sted temperature of the secondary side and centrols pri=ary system pressure at saturation. The cold leg te=pera-ture may re=ain slightly subecoled. If the HPI refills and repressuri:es the RCS, the ho: legs can beceme subcooled. The i= mediate cperator acti:n i.s to trip the RC pu=ps upon receipt of the low pressure ESFAS signal and then verify ESFAS functions. The operator =us: then verify that the HPI train flow is balanced through each injection line.
Follewup action by the cperator is to verify CTSG 1evel control at 96 inches on SU range and check for established natural circula:ian.
This is done by gradually depressuri:ing the steam generators. If this test fails, interr.itten bu= ping of a RC pump should be perfor ed as soon as one is available. Continued depressuri:ation of the steam generators with n : ural circulation leads to cooling and depressurization of the RCS. The operator's goal is to depressuri:e the RCS to a pressure that enables the ECCS to exceed core boil-off, possibly refill the RCS, and to ulti=a:ely establish icng-ters cooling.
3.3 LCCA which may Retressuri:e in a Saturated Condition Curve 4 of Figure 2 shows the behavier of a small break dat is too small, in ecmbination wi-Ji the HPI, to depressuri:e de primary system.
j A1 heugh steam generater.feedwater is available, the loss of pri=ary system coolant and -he resultant RCS voiding will eventually lead to interruptien of natural circulation. This is followed by gradual reeressuri:ation of de primary system. It is possible that the Primary system could repressuri:e as high as the pressurizer safety valve setpoint before the pressurs stabilizes. This is shewn by de dashed,line in Curve 4 Once encugh inventory has been lost f cm the i
primary system to allow direct steam condensation in the regions of the steam generators c:ntacting secondary side coolant, the pri=ary system is forced to depressuri:e to the saturation pressure of the secondary
- side, i
T901 Mn l
DATE:
PAGE 11-20-79 19 7 _..
.. -. -. ~.... -
3WP-20007 (6-76) i BABCOCX & WILCOX Nuuta NuC'tA4 Powlt GENitar:oN Om$.oM S t1 60 3-00 TECHNICAL. DOCUMENT Since the cooling capabilities of the secondary side are needed to centinue to remove decay heat, RCS presse s will not fall below that en the secondary side. HPI flew is sufficient to replace the inventory los: to boiling in the core, and condensa:ica in the steam generators removes decay hea energy. The RCS is in a stable ther al conditien and it will re=ain there until the coerator takes further actien. The pressuri:er level response is cha'racteri:ed by Curve 3 of Figure 3 during the depressuri:ation, and Curve 4 of Figure 3 during the temporary repressuri:ation phase. The dashed line indicates the level Schavior if pressure is forced up to the pressuri:er safety valve setpoint. During this transient, hot leg te=perature will rapidly approach satura: ion with the initial system depressuri:ation, and it will remain saturated during the whole transient. Cold leg te=perature will appr:ach saturstion as circula-tion is lost, but =ay re=ain slightly subcooled during the repressuri:2-tien phase of the transient. Later RCS depressuri:stion could cause the cold leg temperatures to reach saturatien. Subsequent refilling of the pri=ary system by the HPI might cause te=porary inter uption of steam condensation in the steam generator as the pri=ary side level rises above the secondary side level. If the depressuri:stion capability of the break and the HPI is insufficien: to offset decay heat, the pri:ary system will once more repressei:e. This decreases HPI flow and increases loss through the break until enough RCS coolan: is lest to ence =cre alle direct steam condensation in the steam genera cr.
This cyclic behavier will s:07ence the HPI and break can balance decay heat or the opera:c takes some action.
The cuerstor's i: mediate acticn is to trip the RC pu=ps upon receip:
of th'e low pressure ESFAS signal and verify the cempletion of all ESFAS functions. The operater should then balance HPI ficw. Following tha:,
he shculd verify steam generater level con:rol at 96 inches indicated and check for natural circulation. If it is positive, he should depressuri:e the steam generaters, cool and depressuri:e the pri=ary system, and atte=pt to refill it and establish 1cng-term cooling.
If the system fails to go into natural circulatien, he should cpen the PCRY lcng enough to bring and hold the RCS near the secondary side pressure. Once natural circulation is established or a RC pu=p can be bu= ped, he will be able to continue depressuri:ing the RCS with the steam generators and establish long-term ecoling.
3.4 Small I.CCA which Stabilizes at P > Psec Curve 3 of Figure 2 shows the behavior of :he RCS pressure to a break f
for ichich high pressure injection is being supplied and exceeds the leak flew before the pressei:er has emptied. The pri=ary system s subcooled and natural circulation to the steam genera:c re removes core decay heat. The pressurizer never empties and centinues to control primary system pressure. The operator needs to trip the RC puses and ensure thar ESFAS actions have occurred. Fo11cwu actions include pressuri:er inventory centrol after the RCS is 50"p 1
?
subcooled and verification that natural circulation is established if the RC pumps are tripped. A restart of the RC p s under these conditions is desirable for plant control.
DATE:
11-20-79 PAGE goDM l
t
i
._.....---a._.-..."
l o
j i
3a?-20007 (6-76)
BASCOCK & Wil.COX
,,u w s:
e.ucitaa Powta etNEAAr:cN OivisioN
'6 3#
TECHNICAL DOCUMENT 3.5 Small 3reaks in Pressuri:er The system pressure transient for a small break in.:he pressuri:er will behave in a manner si=ilar to that previously discussed. The initial depressuri:ation, however, will be more rapid as the initial inventory loss is entirely steam.
The pressuri:er level response for these accidents will initially behave like a very small break without auxiliary feedwater. The initial rise in pressuri:er level shown in Figure 4 will occur due to the pressure reduction in the pressuri:er and an insurge of coolant into the pressurizer frem the RCS. Once the reactor trips, system contraction causes a decreasing level in the pressuri:er. Flashing will ulti=ately' occur in the hot leg piping and cause an insurge into the pressuri:er. This ultimately fills the pressuri:er. For the remainder cf the transient, the pressuri:er will remain full.
Towa-d the later stages of the transient, the pressuri:er =ay contain a two-phase mixture and the indicated level will show tha:
the pressuri:er is only partially full. Except for closing the PCRV block valve, operator actions and system response are the same for these breaks as for 'similar breaks in the loops.
4.0 SMALL 3REAXS WITHC17T AUXILIARY FEEDWATER There are th.ree basic classes of break response for small breaks without auxiliary feedwater. These are:
1.
Those breaks capable of relieving all decay heat via the break.
2.
Breaks that relieve decay heat with both the HPI injection and via the break.
3.
3reaks which do not automatically ac:': ate the HPI and result in system repressuri:ation.
The system pressure transients for these breaks are depicted in Figure 5.
4.1 LCCA's Large Enough to Deeressuri:e Reactor Coolant System Class 1 (Curve 1 of Figure 3), RC system pressure decreases smoothly throughout the ::ansient. For the larger breaks in this class, CFT act':ation and LPI injection will probably occur. For the s= aller r
breaks of this clas's only, CFT actuatien will occur. Auxiliary feedwater injection is not necessary for the short-term stabili:ation of these breaks. The pressuri:er level for this transient rapidly falls off scale. Operator acti:n and plant response are similar :o those described for this class of breaks with a feedwater supply.
T20152 DATE:
11-20-79 21 AE i
s-s 3WP-20007 (6-75)
SABCOCK & WILCOX e.um NUC'.1AE Powlt CENER AT:oM Olvi$iCN 69-tic 6cos co TECHNICAL DOCUMENT 4.2 LCCA's which Reach a Semi-Stabili:ed S:ste 1
For Class 2 (Curve 2 of Firre 5) breaks, the RC pressure will rapidly reach the icw pressure ESFAS trip si;nal (about two to three minutes).
With the HPI's on, a slow system depressuri:ation will be established coincident with the decrease in core decay heat. No CFT actuation is expected. Auxiliary feedwater is not necessary for the short-term stabili:stion of these breaks. The pressuri:er level for this tran-sient rapidly is11s off scale.
The operator needs :o trip the RC pu ps upon the low pressure ESFAS signal, verify co=pletion of all ESFAS functions, and try to establish secondary side cooling. Salancing of the HPI must also be perfor:ed.
If steam generator feedwater cannot be obtained and RCS pressure is increasing, the operator should open the FORV and provide all the HPI and =akeup capability possible. The goal is to depressurize and cool the core with the ECCS, the FCRV, and the break. If secondary side cooling is again established, the cperator should verify natural circulation, and if unavailable, bump a RC pu=p to complete RCS c eldown with the steam generators. A: this point, the PCRV can be closed, the sys:en refilled, and long-term cooling established.
4.3 S:211 LCCA's Which do not Actuate the ESFAS Automatic ESFAS acitation will not occur for Class 3 (Curve 3 of Firre 5) breaks. Once the SG secondary side inventory is boiled off, system repressuri:stion will occur as the break is not capable of re=cying all the decay heat being generated in the core. System repressuri:atica to the FCRV or the pressuri:er safety valves will occur for smaller breaks in this class. For :he ":ero" break case, repressuri:stion to the PCRV will occur in the first five =inutes. Cperator action is re-quired within the first 20 =inutes to ensure core coverage throughout the transient. For 03-1, this action is manual actuation of auxiliary feedwater for a small break. For a ":ero" break, the combined use of the MU system, startup feedwater pu=p, and FORY at high RC pressures (above the shutfeff head of the HPI) has also been shown to provide acceptable results. In all cases, AFW should be restored as quickly as possible.
The establishment of auxiliary feedwater will rapidly depressuri:e the RCS to the ESFAS actuation pressure, and syste:s pressure will stabili:e at either the secondary side SG pressure or at a pressure where the HPI equals the leak rate. Upon receipt of the low pressure ESFAS signal, the operator zus: trip :he RC pumps.
r For the Class 3 breaks, pressuri:er level response will be as shown in Figure 6.
The minimum refill ti=e. for the pressuri:er is that for the ":ero" break and is shown in Figure 6.
After initially drawing inventory from the pressuri:er, the system repressuri:stion will enuse
.he pressuri:er level to increase, possibly to full pressuri:er level.
Cnce :he operator action to restore auxiliary feedwater has been :sken, the system depressuri:stion will result and cause an outsurge frem the pressurizer. Ccmplete loss of pressuri:er level may result. For :he smaller breaks in Class 3 which result in a system repressuri:stion l
following the actuation of the HPI system, pressuri:er level will increase and then stabili:e.
i
____3 i - ma
^
DATE:
11-20-79 22 l
1
. J l
w
-~
y W ""'
3WP-20C07 (6-76)
SABCOCX & WILCOX e.u,.i n 3.uctea Pown casuar:cm omsio" 69-1106003-00 TECHNICAL DOCUMENT Without auxiliary feedwater, both the hot and cold leg temperatures will satu :e early in the ::ansient and, for the Class 1 and 2 breaks, will remain saturated. For the Class 3 breaks, once auxiliary feed-water is established, the cold leg tedperatures will rapidly decrease to approxi=ately the saturation tempers:ure corresponding to the SG secendary side pressure and will remain there threughout the remainder of the transient. Ho: leg te=peratures will remain saturated throughout the event. The operator needs to verify autc=atic actuation of all ESFAS actions on icw pressure, balance HPI flew and a::e=pt to restore secondary side cooling. In the =cantime, he should actuate the startup feedwater pump and =akeup pumps and open the PORY (if pressure increases) in order to cool the cere and limi: the RCS repressuri:stion. Once feedwater is available, he can close the PCRV and continue the RCS cooldown and depressuri:ation with the steam generators. If natural circulation has not been established, he can bump a RC m to cause forced circulation. The goal is to depressuri:e,.:o where the ECCS can refill the RCS and guarantee icng-term cooling. '
4.4 Small Breaks in Pressuri:er 9
See the writeup for small breaks in pressuri:er with feedwater.
Small breaks in the pressurizer will differ frem those in the Icops in the sa e manner as those previously described in the section addressing small breaks in the pressuri:er with auxiliary feed.
5.0 TRANSIENTS WI"E INITIAL RESFCNSE SIMILAR TO A SMALL 3REAK Several transients giv9 initial alarms similar to small breaks. These transients will be distinguished by additional alarms and indications or subsequent system tesponse.
Over:coling transients such as steam line breaks, increased feedwater flow, and steam generator overfill can cause RCS pressure decreases with low-pressure reactor trip and ES7AS actuation. Su: steam line breaks actuate icw steam pressure alarms for the affected steam generster, and steam generator overfills result in high steam generator level indica-tiens. The overecoling transients will repressuri:e the primary system and will result in a subccoled condition during repressuri:ation. The immediate actions for both overceoling and small break transients are the s=me, including tripping of the RC, pu=ps.
The operator will recognize overecoling events during repressuri:stion, if not scener, and is instructed to restart the RC pumps, if sube oled conditions are esrablished, by the small break operating instructions. -
A loss-of-feedwater transient will result in a high reactor system; pressure alarm but does not give an ESFAS actuation alarm.
T20154 DATE:
11-20-79 PAGE 23
l 3'T?-20007 (6-76)
SABCOCX & WILCOX su-su suc.ua nowna casuarcs oms;o" 69-1105003-00 TECHNICAL DOCUMENT A loss of in:egra ed control system power ::ansien; s: arts with a high RC pressure trip. After the reac:c: : ip, this beccmes an overecoling ::ansient and will give low reactor system pressure and possible ESFAS actuation. Steam generator le.els re= sin high and the systes becomes subccoled during repressuri:stien.
Design features of the 35W NSS provide automa:ic protection during the early par of small break ::ansients, :hereby providing adequate ti=e for small breaks to be identified and app cpriate action taken to protect the system. The only p cmpt =anual operator action required is to trip the RC pu=ps once the low pressure ESFAS signal is reached.
6.0 TRANSIENTS THAT MIGHT INITIATE A LCCA
' There are no anticipated ::ansients that might initiate a LCCA since the PCRV has been rese: to a higher pressure and will no actuate during anticipated ::ansients such as loss of main feedwater, turbine trip, c: loss of off:ite pcwer.
Mcwever, if the PCRV should lift and fail to reset, there are a nu=~cer of indicatiens which differentiate this ::ansient f cs the anticipa:ed transients identified above. These include:
o ESFAS actuation o-Quench tank pressure /te=perature alar =s o Saturated pri=ary systes o Rising pressuri:e level o High quench tank level o High centain=ent su=p level o High centain=ent pressure These additional signals will identify to the operator that in additien to the anticipated transient, a LCCA has occurred. In the unlikely event that s=all breaks other than a =alfunctioning PCRV occur after a ::ansient, they can be identified by initially decreasing RCS pressure and convergence to saturatien conditions in the reac:cr ecolant. Small break repressuri:2:icn, if it occurs, will follow satu 2:icn conditions.
By remaining aware of whether the reactor coolant remains subecoled or becemes saturated after ::ansients, the operator is able to recogni:e when a small break has occurred.
T. 0 HPIMM TURO'I LI M For s=all LCCA's, the HPI/W system is needed :o provide =akeup to the RCS and sust remain operable unless specific cri:eria are satisfied.
The basis for these criteria are described belcw.
T2015.5 DATE:
11-20-79 PAGE 24 eep
" dunkN ** N een g-o,.e.
m M
- 'O L
..-.... ~
c 3'A*P-20007 (5-76)
BABCOCX & WILCOX w,.. n WC'.1A4 Powlt otNUAT;oM DmhoM 69-1106003-00 TECHNICAL 00CUMENT For certain small breaks, system cepressuri:st:on w:11 result in LPI actuation. Since the LPI is deuigned to provide injection at a greater capacity than the HPI, temination of the HPI is allowed.
However, this action should only be taken if the flow rate through each line is 2: least 1000 gpn and the situation has been stable for 20 minutes. The 20-minute time delay is included to ensure that the
-system will not repressuri:e and result in a loss of the LPI fluid. In the event of a cere flooding line break, the LPI fluid entering the breken core flooding line will not reach the vessel. Thus, in order to ensure that fluid is continually being injected to the RV for all breaks, the LPI =ust be providing fluid through both lines. The 1000 gym is sufficient to re=ove decay hea: and ensures that upon terminatien of the HPI pc=ps, adequate flow is being delivered to the RV.
Throttling or ter=ination of the HPI/MU flow is also allowed if all the following criteria are met:
A.
Hot and cold leg te=peratures are at least 50*F below the saturation tempera: = es for the existing RCS pressure.
B.
The action is necessary to prevent the indicated p'ressuri:er level frem going off-scale high.
Under these conditions, the pri=ary system is solid. Continued HPI/MU flow at full capacity =ay result in a solid pressuri:er and continued
=akeup would result in a lifting of the PORY and/or the pressu-i:er code safety valves. This-cay in turn lead to a LCCA. Thus, flow shecid be thzettled to =aintain a stable inventory in the RCS. However, if the 50*F subcooling cannot be =aintained, the HPI/MU shall be i==ediately reactivated.
HPI/MU flows should also be throttled to prevent violation of the ail-ductility te=perature @UT) for the reactor vessel.
This concern can only arise if the fluid te=perature within the reactor g
vessel is at least 50 p subecoled. A curve of the allowable downc==er temperature for a given RCS pressure is provided within the operating guidelines. The downec=ber te=perature is deter =ined by one of two methods:
1.
If one or more RC pumps are operative, the cold leg RTD reading will be essentially the sa=e as the reactor vessel downce=er temperature.
2.
Without the RC pu=ps operating, the cold leg RTD's may not provide
.... temperature readings indicative of the actual-RV downcemer :espera-
- =e as a stagnant pool of water =ay exist at these locations. The incore ther= occupies will provide :he best indicator of the down-comer te=perature and should be utili:ed if no RC pu=ps are available.
In. order to acccunt for heat added to the fluid from :he core,150*p must be subtracted frem the incere the=occuple readings to reflect the downcomer te=perature. This method will result in temperatures which will be lower than the expected downce=er temperature. Thus, use of this sethodology assures that NDT will not be a p;cblem.
DATE:
11-20-79 PAGE 2ST20156 i
- w a
m.
v
.. - - -. - ~. -.. -..
4 3'7t?-20007 (6-76)
BASCOCK & WILCOX Num e t t NUC!.Aa PCwit GINt2AfiCN cm3.CN 69-6cos-co TECHNICAL DOCUMENT Figure 1 Break Spec::r.-Average Syster Void Frac: ion With the RC Pt=ps Cperative and 2 HPI Pt=ps 100
[ f 24- ~ ~ %,y --
~*'
- k / h/' 5//
~
///
8
~ ;,7,y 50 z
/
i
/
/
m v
/
40
/
/
1 Q.D1g 11/.#.#.
t /
3
/,/
/* /*
l, t
20 _/ /
/*/
/
0 0
400 500 1200 1500 2000 2400 2300 Time, sac l
T2015'7 DATE:
11-20-79 26 PAGE
==_e
,m y
..~..- __ _.._.._......._.
S'4s?-20007 (5-76)
BABCCCX & WILCOX
- m...
Nuc1A4 #Cwta GENEIAffcN cm1;CN TECHNICAL 00CllMENT 69-1106cas-co Figure 2 Pressure Vs Ti=e-Small Breaks wi:h Auxiliary Feedwater 2500 j--- 3
/l
\\
/
I
/
I
~
2000 e
s' I
=.
- 1 L}
l i
1500 1
=
g 3
4
\\
\\
a.
@/
1000 2
500 0
500 1000 1500 2000 2500 3000 3500 4000 Tiss, sac e
T2015S DATE:
11-20-79 PAGE
-~
mee g e e g N
+ - -
y.
,--.-w--
n
.--e.--
v
~
. ~. _
j 3WP-20007 (6-76)
SABCCCX & Wit.COX Nume NyctAa PCwt2 GENttAT;CN OlvtSicM 69-1106003-00 TECHNICAL DOCUMENT s
Figure 3 Pressuri:er Level Vs Time -
Small Breaks with Auxiliary Feedwater 1
i 100 F
5 I
l
)
g p.
80 f
g
\\
/
/
l
/
{
50
/
I
/
~
/
I 5
/
l-E 40
/
l E
=
I.
a
[
20 I
l 4
1 W
s
,1 g
0
' 500 1000 1500 2000 2500 3000 3500 l
l Time, sac f
P T20159 DATE:
11-20-79 PAGE
-~y eo e
w--,,.,,r m-s,_
~,me,,-wo-,,,.w-,,-,
y--
+--n-
I l
..y.t-.
\\
e 3'. :re-2cco7 (6-76) b e
BABCOCX & WILCOX
'I NUCIAA PCwit GEND AT:CM Olvt$iCN 6'~
6 3-TECHNICAL DOCUMENT Figure 4 Pressuri:er Level Vs Time for Small 3reak in Pressuri:er 100 m
p 75
"_=
_=
c' a
me
-=,.
- 0 9 e.
25 O
t 200 R3 500 300 1000 Time, sac i
T20160 DATE:
11-20-79 pggg 29
. - ~ ~.
--m
.~
9
---y
,,--y-
~-w,
SWP-20007 (6-76)
)
r 1
SABCOCX & WII.COX au-se muc 3a towns casuAr:os oms.
- 69-1106003-00 TECHNICAL. DOCUMENT Figure 3 System Pressure Vs Time -
Small Breaks w/o Auxiliary Feedwater
=,
2500
~
"Z5R0" fLIAK 3
gy3tt (7) l
/
2000
/
/
/- -
l a
/
- 1500 -
/
i s
W.
J V
~
" 1000
\\ URGE ($
500 i
0 0
500-1000
!!00 2000 2500 3000 3500 4000 J
l i
Time, sac l
l I
t l
T20161
. 79 00 DATE:
PAGE
.._...--....c..
.i v.
T4N?-20007 (6-76) 3ABCOCX & WILCOX mean NUCI.Aa Powta CINER.AT:CN Civt31CN TECHNICAL. DOCUMENT 6S-u ecos-co Figure 6 Pressuri er Level Vs Tir.e -
Class 3 Breaks w/o Auxiliary Feedwa er 100 "ZER0" F -
BRDX D
80 l
a I
3 60 l
5 l
QNLY FOR SMALL CLASS 3 "i
BRDXS l
1
/
4a I
p I
I 2G I
I Q
e i
1 e
e f
G 500 1000 1500 2000 2500 3C00 3500 4000 Time, sac T20162 31 DATE:
11-20-79 PAGE l
[
9
&e
-ge
-m m-.,wa
,----------c.
.%_.,r
. --,. ~,
,-w-7,,,w,.,,w,
,,y-,
,,.%-,m,.w..
. ~ _ _. _. _
stin -20007 (6-76)
BABCOCX & WILCOX a.u-s e NUC'!A4 POWER GENf2AUoM OiVl$iOM TECHNICAL DOCUMENT 68-1 6C 3-INADECUATE CORE CCCLING - CESCRIPTION CF PLGT BEHAVICR 1.0 INTRCCUCTICN Follcwing a less-of-c clant accident CI.CCA) in which the reactor trips, it is necessary to re=ove the decay heat f c= the reactor core to prevent da age. Core heat re= oval is acc:=plished by supplying cooling ware to the core. The water which is available for care cooling is a portion of the initial reactor coolant syste (ACS) water invento:y plus any water injected by the e=e:gency core cooling syste (ECCS).
The heat added to the cooling water is rs=oved via the stea generator and/or the breck.
As lcng as the reactor core is kept covered with a =ixture of water and stes=, cere ds= age will be avoided. If the supply of c cling water to the core is decreased c: inter:upted, a Icwer =ixture level in the core will result. If the upper po::icns of the es:e becc=es uncovered, c oling for these regiens will be by fe:ced ccnvectica to superheated stes= which is a 1:w hea: ::ansfe: regi=e. Conti = ed operation in the stes= cooling = ode will result in elevated core te=peratures and subsequent c= e ds= age.
2.0 LCSS CF RCS INVENTCRY WI~H PfACTOR CFCLE' PO!PS OPERATING With the RC pumps operating during a s=all break, the stes= and water will re=ain =ixed during the ::ansient. This will resul: in liquid being discharged cut the break centinucusly. Thus, the fluid in de RCS can evolve to a high void fraction. The void fraction of the RCS indicates t.".e ratio of the volt =e of stes= in the RCS to the total volt =e of the RCS.
Since the RCS can evolve to a high void fracticn f0: ce::ain s=all brer.ks with the RC pu=ps en, a RC pu=p ::ip by any =eaas (i.e., loss of effsite power, equip =ent failure, etc.) at a high void fractien during the small break ::ansient may lead to inadequate c=re c:oling.
That is, if the RC pu=ps ::ip at a ti=e peried when the syste void l
fraction is greater than app :xi=ately 30%, a core heatup will ec ur because the a=ount of wate: left in the RCS would not be sufficient to keep the core covered. The cladding te=perature would increase until core cooling is re-established by de ECC systems. For certain break si:es and ti=es ei RC pump dp, acceptable peak cladding te=peratures during the event could not be assured and the core could be da= aged. Thus, p c=pt cperato: action to ::ip de RC pu=ps upon receipt of a low pressure ES7AS signal is required in order to ensure that adequate core c cling is provided. policwing the RC pu..p ::ip, the s=311 break ::ansient c:ncerns abcut inadequa:e cere c: cling will be the sa=e as described in the previcus sec:icn.
T20163 DATE:
11-20-79 PAGE 32 en--*.N 4
N e.e ge Mg.
S p--
a m
9
-9 7,--e
--q_-
.,,,,.,?
,9 m
,9 e.
,ep.
...... ~.......
T U. i.
3WP-20007 (6-76)
B AB COCys & WILCOX suwu sucm rowa otsuces :msic" 69-1106003-00 TECHNICAL. DOCUMENT If the RC eunos 'can not be tripped by the operator, the continued forced circulation of fluid throughou: the RCS will keep,the core eccled. Mcwever, if little er no ECCS is being provided to the RCS, the fluid in the RCS will eventually bec:ce pure steam due to the continued energy additica to the fluid provided by the core decay heat. Under these circumstances, an inadequate core cooling si:uation will exist. Since the heat removal process under forced circulation is be::er than the steam cooling =cde described belcw for the pu=ps off situation, the operator actions and indications described in the subsequent section are sufficien: for inadequate core c oling with the RC pu=ps operating.
3.0 LOSS OF RCS INVENTCRY WITH0tr REACTOR CCOLWT POtPS OPERATING Without the RC pu=ps operating, the cooling of the core is acce=plished by keeping the core cevered with a s:eam-water sixture. As the fluid in the core is heated, sc=e of it er all of it =sy be tu ned to steam.
If insufficient cooling water is available to =sintain the steam-water mixture covering the core, the core exit fluid :e=peratures will begin to deviate frem the satura:icn temperature cor esponding to the pressure of the RCS. One i==ediate indication that inadequate core cooling =ay exist in the core is da: the te=peratu e of the core exit ther=ccouples and hot leg RTD's are superheated. At this condition inadequate core cooling is evident as the core will be partially unc=vered. However, the degree of uncovery is not severe encugh to cause core da= age. This condition is not expected to cccur but is not, by itself, a cause for extre=e action. If the ECCS systems are functioning nor ally, the temperatures should return to saturation without any actions beycnd th:se outlined for a small break. For inc:re ther=ccouple temperature indicating superheated conditions, the opera:cr ~ should (a) verify emergencv cooling water is being injected thrcugh all HPI no::les into the RCS, (b) initiate any additional scurces of ecoling water available such as the standby makeup pu=p, (c) verify the steam generator level is being enintained at the emergency level (d) if steam generator level is not at 95% of operating range (96 inches indicated on the startup range for raised Icep plants), raise level to the 95% level, (e) if the desired steam generator level cannot be achieved, actuate any additional available sources of feedwater such as star ue auxiliary feedwater pu=p, (f) establish 100 7/hr ecoldewn of RCS v3.2 steam generator pressure control, (g) cpen core flooding line isolation valves if previously isolated, and (h) if RC pressure increases to 2300 psig (1500 psig for 08-1) open the pressuri:e PCRV to reduce RC pressure and reclose PCRV when RC pressure falls to 100 psi above the secondary pressure. These actions are directed toward depres-suri:atien of the RCS to a pressure at which the ECCS water input exceeds core steam generation. The align =ent of other scurces of ecoling water is the recogni:icn tha: the injection of the HPI system alene is not sufficient to exceed core boil off.
T20164 DATE:
11-20-79 PAGE 33
. _... _ _. ~. _._
._...____e
- ..p SWP-20007 (5-75)
SABCOCX & WILCOX av=sem
~ucua rown ca euwes omsics 69-1106c03-co TECHNICAL 00CUMENT If the ince:e the=occuple indica:icas reach Curve #1 en Figure 3 in Par: I, de peak fuel cladding te=perature has reached app:cxima:ely 1400 F.
Above this te=perature level -here is a potential ic cladding C
rupture. Also, the :ircaloy cladding water rea : ion will begin to add a significm: a= cunt of hea: to de fuel cladding dereby greatly -
increasing the possibility of c :e st:.:ctural damage unless adequate
=
core cooling is res:cred. Ncn-cendensible gas fema: ion will increase,.
rapidly ihm dis level ei fuel clad te=perature.
For incere de=occuple te=perature indications at or exceeding Curve
- 1 en Figure 3 in Part I, the cperator shculd Ca) start ene RC pu=p in each loop. (b) depressuri:e the stes= generator as rapidly as C
possible to 400 psig c: as far as necessa:y to achieve a 100 F decrease in saturatien te=pera:ure, (c) i=ediately centinue the plant ecoldewn by maintaining a 100 7/n: decrease in secondary saturatien te=perature to achieve 150 psig RC pressure, (d) open the pressuri:e:
pilot cperated relief valve CPCRV), as necessa:y, to relieve RCS pressure and vent non-cendensible gases. The operator actien in T
starting the RC pu=ps will previde fe:ced flev ccre cooling and will
- tduce the fuel cladding te=pera:=es. The = pid depressurizatica of the stes= generators will help to depressuri:e de primary system to the point where de core f1 ceding tanks will actuate. S:cpping de depressurizatica at 400 psi; (c: at a reductien. in satura:icn te=perature of 100 7) will =aintain the tube to shell te=perature difference within 0
the 100 F design li=it.
The c:ntinued cooldewn to 150 psig will reduce the pri=ary syste= pressure to the point where the Low Pressure Inj ectica Syste= can supply ecoling. The cpening of the PCRV will also help to depressuri:e the pri=ary syste=. The PCRV shculd be closed when the pri=ary pressure is wicin 50 psi of de secondary pressure and then shculd enly be used as necessary to maintain the pri=a:y syste= pressure at no greater than 50 psi above the sec ndary syste= pressure. This
=ethed of cperatien will =inimi:e the Icss of water f c= de p:4m y syste=.h:cugh the PCRY.
If the incore de=occuple readings reach Cu:ve #2 en Figure 3 in Part I, C
the peak cladding te:.perature is app::xi=ately at de 1300 F level. This is a very sericus cenditien. At this level of clad te..perature, significant amcunts of sen-cendensible gas are being generated and c re ds= age may be unavoidable. Extre=e =easures are required by the cperater to prevent
=ajor core damage. The goal of these acticns is to depressurice de RCS to a level where the core f1=oding tanks will fully discharge and de LFI syste= can be ac.uated hus p cviding p c=pt core recovery. *he cperator shculd Ca) depressuri:e the stes= generators as rapidly as possible devn to 50 psia, (b). start the re=aining RC pu=p and (c) open the PCRY and leave it open.
1 T20165 DATE: 11 20. g PAGE 34 me4
- -8"
- --e
.e e y e
n.
e 4-me up
.m
..._.._r...-
_ ~..
O 9
- \\. '*
3W P-20007 (6-76)
+
9 BASCOCX & WILCOX w,n wcma ecwn casu4 ten smsic" 69-1106003-00 TECHNICAL DOCUMENT 4.0 INADEQUATE CCRE CCCLING RESULTING FRCM LCSS OF STE.Ut GENERATOR HEAT SINK For a very small or non-LCCA event, the core decay hes: removal is acco=clished via che steam generators. If that heat renoval is decre' sed or lost, the natural circulation of fluid within the RCS a
say be reduced er stopped. The loss of natural circulation for core cooling will eventually boil off the remaining water inventory in the core and lead :o inadequate core cooling and elevated core te=perature. Indications of loss of steas generator heat sink include (a) a low level in the stea: generator with low s:eam pressure, (b) temperature indicators in hot legs show saturated temperatures, (c) increasing RCS pressure. The opera:or should try to establish emergency feedwater as quickly as possible and i==ediately actuate the HPI system to restore natural circulation and RCS heat removal.
If auxiliary feedwater is no: available and :here is no break in the RCS, the system will repressuri:e and decay heat will be re=oved by opening the PCRV and =aximi:ing HPI addition.
For this plant, system repressuri:stion could result >in a loss of the HPI pu=ps because of the icw pressure (< 1300 psig) shutoff head.
For this plant, the ccebined use of the MU syste=, s:artup feedwater pu=p and the PCRV is required to ensure adequate core cooling.
T20166 I
i l
DATE:
11-20-79 PAGE 33
)
i 4
. ~..
='*-w
- wue ens.
g.
-eg8.**
b
- ..d' 6 e d.w.t.s.-.hw wh ee
% 4% e.i'
=M M heg-M**
- .-dD e
g..y.~.
o
,a e
S
- a.
- D
.. S I
e 9
i
<.e
,#.9
's e
'I.
f.3 g,,
- e*
I
(
af
'l3:
- r. e s
- a-s.
@.l'.
t
-4
.3 9.
4 g.
h a-g
.=
g" e.
).
5
..g.
e f
. 1 i
s.e.
.e I-,.r, 4
.,,e t
P 4.
et d
' 43 I
y{.e
-l
?
x V.
p
.-o
. v.
4 <.....
- s
.}..
t r-T t
_ g
..e
.*.Q
.H.e q
e.
e..
.8.9*
e e
,s:,
s.t 8
h e
O 4
I.
t M
4 g
.y 9
g
-n.
.g*..
e.
.o._
e -.
.o.
,..,s
.. (.
P-
..,.@.euj
).4 O M
- ..,..k...
.g
.S eb*f 8 O a
e eI
,g g
r.
.-.. '.e e
,.. '- e.
.g e
e..
..; 12.
.v.-..,,..
..m
..*~
.. g.w.. n n. _,
s
.m....g e
,..g.
...g-
.-.==s.
p.
.. A t..
p.
..e.
...e.
e e.,.
g
....wgw..
.e..=
".".*,,....e.
...e..
.ew e.
.o
- .NM*%..#
,..,t s
g g
. =...
. e.u.
p.
..gg.
..M.f
- b*
h '.* 4
..,M...e.O.-..
.M*e w..s.
e
.....*...=. _
g
..e.dg,.
6
. 6 g
g
.*..e*.e.e.h.--4**e s
.'.M..m. ee@%. ee
- g..'..........
....s...m.
s,
.g
=
e.
.... =.. =... -.........
.g3...e.e..... e.M a4M.....
- e.. - -....
..-.a
. + *.
J'......r--
1
- x. g fe ~*..
g.e av,*y
..em= :. <=
.s
. = =. =.
1
- a.....s.-
.1 w.==.
.. -_ =.. -.... -..................
A
.,.......,.y.....*
.ev.'M *.
- ...~ge.'*.L*.
...q,
- * *f '
1 * '.%.
.w.. ;*...: '
.r..
..3a er.
..'s..
..'.'a.
.p.
. < *....-J..p
. g *
- y...; s.+ m,--.....=7.
,,,, =.
r-2.-r....
.wr--..-
-w G.*.'
, e a.
- 'N"#'s.e.
e e we,._
.we
-