ML19257C285
| ML19257C285 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/01/1980 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | |
| Shared Package | |
| ML18044A457 | List: |
| References | |
| PROC-800101, NUDOCS 8001250508 | |
| Download: ML19257C285 (39) | |
Text
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ATTACHMEtlT BEST ESTIl%TE ftSL3 A!!ALYSIS TO ASSESS flSSS Aft 0 C0ITAIt:ME?iT RESP 0:lSE MITH AUT0ttATIC AUXILIARY FEEDWATER ACTUATICil i809 260' Combustion Engineering January, 1980 8001250 EOY
l.0 ItlTR00UCTt0:1 s
A set of calculations has been performed on a generic basis with plant characteristics representative of CE operatinq plants to nodel containment building pressure and temperature response and overall flSSS behavior, including core reactivity, following a liain Stean Line Break (liSLB) inside containment. The intent of these calculations is to deternine if the containment building response (pressure) and the core reactiv'ty response (return to power) are acceptable following a fiSLB whn auxiliary feed-water is added without regard to the identification of the affected stean generator. The auxiliary feedwater flow is assumed to be activated at the initiation of the transient to maximize its effects. fiain feedwater flow including post trip rampdown is simulated. fio isolation of main or auxiliary feedwater is considered unless a high water level condition is reached.
2.0 ASSUit?TI0 tis A:D CA3ES Assunptions for the analyses are given.in Table 1.
The four cases analyzed are listed in Table 2.
3.0 ~ DISCUSSICil 0F D.ESULTS
!!aximum containment pressure and least negat.ve core reactivity for the four cases are listed in Table 3.
Both the containment pressure and the reactivity (return to power) values are within acceptable limits, liain feedwater flow, auxiliary feedwater ficw, core reactivity chance, core power, containment pressure, primary loop temperatures, and steam generator secondary temperatures for the four cases are detailad in Figures A-1 through A-7, 3-1 through B-7, C-1 through C-7, and 0-1 through D-7, respectively.
The results of the analyses using best estimate codels for steam generater moisture carryover and containnent cassive heat sink heat transfer demonstrate that the additional auxiliary feedwater has a negligible impact on containment peak pressure.
The containnent peak pressure is detemined primarily by the initial inventory in the ruptured unit.
This 1809 261
inventory is released within the first few minutes, dependng upon the 5
break si:e, so that the contribution of auxiliary feedwater flcu to the ruptured unit over this tire frame is small. Over the lancer time franc, the secondary inventory is boiled off at essentially the decay heat rate which the containnent a,tive heat removal systems can accc=odate while reducing containment p11ssure. The excess feedwater which is not boiled off remains in the steam generater, causing the secondary level to rise.
Ti. centainnent peak pressure is essentially an initial inventory limited phenomenon.
The results of the analyses also shcw that the additional auxiliary feed-water has a negligible impact en core reactivity.
Cases A and C assune no stuck rods and a best estinate moderator cooldown curve.
For cenparisen, Cases B and 0 assume that the most reactive red is stuck and that the moderater cooldcwn curve is a licensing curve. All cases took credit for boron injection via three charging pumps; hcwever, safety injection boron credit was not taken. These cases do not have a return to power for the follcwing. reason. The initial prinary loop temperature decreases are limited 2
by' the two-phase blowdown process associated with large break P2 f t ),
since much of the break flow is saturated liquid which has not absorbed significant amounts of energy frca the prinary loop, tor staller break 2
areas (c2 ft ), the blowdown is pure steam which does require large amounts of energy per unit mass to boil via primary to secondary heat transfer; however, the rate of primary-to-secondary heat transfer is controlled by the blowdown ficwrate which in turn is limited by the small break area.
The net result is that over approximately the first 100 seconds of the event, the amount of ccre and loop cooldown is about the sace regardless of break size. This time frame is most important since.the presence of delayed neutrons minimizes the amount of cooldewn needed to produce a core criticality problem.
Without a return to power (via primary loop cooldewn and delayed neutrons),
the remainder of the transient is a gradual increase in reactivity due to loop cooldewn which is coupled to the centainnent pressure, plus a decrease in reactivity due to boren injeccien.
In time (aporeximately KO sccends),
the reactivity decrease due to beration overtakes the reactivity increases due to loop cocidewn; thereafter, the total reactivity steadily decreases.
The ruptured steam generator is at the containment backpressure and with 1809 262
RCPs operating the sensible heat from the non-ruptured unit is quickly removed resulting in RCS and SG secondary temperatures essentially in equilibrium with the containment conditions in about 10 minutes.
With licensing assumptions, the peak in the reactivity transient is calculated to be within the first two minutes of the event.
A 3 minute time delay, if added to the automatic actuation circuit, would justify a statement that automatic auxiliary feedwater actuation will not impact existing SAR core cooldown MSL3 analyses.
4.0 COMPARISC:1 WITH LICE:ISI m CALCULATIO!is The following items are important in comparing the results contained herein with those obtained with traditional licensing models and assumptiens:
1.
The moisture carryover model used is a best estimate model which gives a two-phase blowdown for large break areas. The two-phase binwdown results in a lower containment pressure and less initial primary loop cooldown than a pure steam blowdown.
Chapter 15 analyses assume a pure steam blowdown regardless of break size.
2.
Chapter 15 analyses assume that the most reactive rod is stock.
Itoreover, the remaining rod worth is assicned a conservative value in conjunction with a conservative moderator cooldown curve.
3.
A best estimate containment heat transfer model provides containment pressurization results significantly lower than those provided in Chapter 6 analyses.
.4 1809 263-
TABLE 1 i
ASSUMiTIC*iS 0@@
f(SSS Initial Conditiens
- 2700 f t'.!';
Power Core Inlet Temperature 548 F Primary Pressure 2250 PSIA Secondary Pressure 875 PSIA Secondary Temperature 529 F Containment Data 6
3 Free Volume 2.5 x 10 ft Design Pressure 44 psig Heat 3 inks SAR values Heat Transfer Model Best estinate codel ilumber of Fan Coolers 4 (no single failure) 6 Fan Cooler Capacity, each 68 x 10 3/hr at 250'F containment tencerature
~
100 F CC'l Temperature Fan Cooler Actuation Setpoint Fans are operational 0t=0 fiumber of Sprays 2 (no single failure)
Spray rate, each 2700 GPit Spray Actuation Setpoint 10 PSIG + 50 seconds Other Data Steam Generator Isolation Signal (MSIS) setpoint 500 psia Decay Heat Curve AftS-5 Main Feedwater Flow Ruptured Unit:
Ramped to 105 over 60 sec:nd-folicwing React:r Tria: (10; represents twice tr.e bycass ncminal value of 51, tais accounts for puro run-cut wi-reduced back:ressure),
temperature is reduced to ic, to account for turnine off_
line.
Flev ter ina:c: if tr.;
elevation of u :01:evel ta:
is reached.
ce ru;ures A_1, 1809 264 B-1. c-1, and o-i-
TABLE 1 ---- continued Main Feedwater Flcw -- continued Unaffected Unit:
Same as ruptured unit except that ficw is ranced to 55.
See Figures A-1, B-1, C-1 and 0-1..
Auxiliary Feedwater Flew Ruptured Unit:
Initiated at t = 0.
Flow rate is a function of unit pressure.
All control valves assumed to be fully opened.
Unaffected Unit:
No flow; all ficw is totally diverted to the ruptured unit.
Reactor Ccolant Pumps Operating during the transient.
CEA Insertion Ucrth All rods in (ARI)
-8.9%
(no stuck rod)
!!ost reactive rod stuck
-7.12%
(bestestimate)
Moderator Ucrth SAR Value See Figure 1 Best Estimate Value See Figure 2 Doppler Morth See Figure 3 Moisture Carryover On Steam Generator Secondary Side Best Estimate Model
~
Baron Injection Parameters Safety Injection Credi.t Hot Taken Charging Pumps Number of Purps 3
Flow Rate 44 GP!1 per pucp Actuaticn Time SIAS 8% by weight Boric Acid Concentration Boron Worth 00 PP!1/5 Boric Acid Conversion Factor 1749 PPl1 boron /5 by weight boric acid liixing Model Used Slug Flcu Model Loop Transit Time 10.5 seconds 9
1809 265
TABLE 2 CASES 2
!!cderator Curve Creak Area (Ft )
A
-8.9 Figure 2 6.63(I)
B
-7.12 Figure 1 6.63(I)
C
-8.9 Figure 2 1.99( }
D
-7.12 Figure 1 1.99(2)
(1) Couble-ended severance of main steam line (two-phase bicudewn).
(2) Largest break area corresponding to pure steam blowdown.
G
'l809 266 e
4 TABLE 3
~RESULTS e Least flecative -
Case Containr.ent Peak Pressure (PSIG)
Core Reaciivity" A
29.7/83.0 (sec.)
-4.31 B
29.7/83.0 (sec.)
-2.34 C
35.0/231.9 (sec.)
-3.54 0
35.0/231.9 (sec.)
-1.55 O
/
e e
e e
~
~1809 267
7 i
i i
i 4
FIGURE 1 REACTIVITY VS l'0DEPATOR TEliPERATURE 6
(SAR VALUE) 7 q
15,*
Z O
P e
. w e D
).
Z
.=
H h
w
~
seo2
<w x
1 0
-1 i
i e
i 300 350 400 450 500 550 600 N,O D m.3..T'm^.:.o. ". 0 3 7..'.'.,, 0 c
i809 268
.s.
7 4
.i i
i i
FIGUP,E 2 P.EACTIVITY VS l'OCEPATCP, TE!'PEPATUP.E (BEST ESTI!! ATE VALUE) 5 s
o.<
a.
.s 7
o p
M
. W' n
w o.-
2 m
}--
H>
s
}--
2 0
g m
x
~
1
~
1809 269'
-1 i
300 350 400 450 500 550 609 MO D E R..,,,. -..., -,. _,, :., o,-
u u ::...r n.
r
6.v FIGURE 3 1.8.l I
DOPPLER REACTIVITY VS FUEL TE",PERATURE i
._. 3,5,
e 1.4 f
- ~ *. -
\\
.D D
.., 3,2 1.0 -
g,g.
g O
g*5 1 l
e g
o,4 :
8 l
+..
s
=
o 0.2 i W
x s
w l
en 0.0 00 1000 1E00 2000 2500 l
b
-0.21
~
g u
-0.4 -
..m.
uw 3,
0.G -
2
.-. 0,g.i F
b
- -. ~. -... ~
. -3,o
.p l
.. I, 4
.t i
1809 270 l
l FUEL TEl:PERATURE *F
J 1800 1500 o
FIGURE A-1 g
v)
N i4gr
~
itAIN FEECIATER r
C FLO'.! V5 III'E 2
O J
u.
1200 cc w
s-
.C 1oww ICCC u.
z
-cr 800 SCO 400 1809 271 200 AFFECTED U; LIT i
Ut!AFF,ECTE0 U::IT I
i i
C I
f f
I J
C 200 400 6CC SCC CCC
- 200 T I tE 5 E : :
wvu 360
_.[
FIGUREA-E 320 Et1ERGEtlCY FEE 0' DATER FLO'J VS TIttE 110 FL0ll TO U.':AFFECTED Ut!IT 280 u
w v3
%r co d
240__
=
O-s 12 cc w
200 s
C 2oww l
u.
160 L
>-o=w o
ce ti.1 5
120
~
l 80 1.
40 ~i 1809 272 1
l I
0 O
200 400 500 SCO l000
- 20:
TIME fSEC]
LU FIGURE.A-3 REACTI'/ITY CHA.'!GES 1
VS-g TIttE 6
n00ERATOR 4
~
2 l
z Lu LJ k
I to D0PPLER CL
~
0
>-u
-2!
C to 50R0tl Cd
-4 TOTAL
-6 ai' il.
t 18'09 273' t
-10 t
I
-- i-0 200 400 SCO S00
,C00
.on-TIME (SEC1
i.w
+
O.T FIGURE A-4 0.30
~
CORE P0uEn vs TIr:E 0.70 0.60 0.50 u:
i w
2o o_
w M
0.4 0.'_
ou I
l l
0L 0.3 I
1 0.2 0 j_
0.10 L 1809 274' i
- 0. 0 0
,ncr
.,, c.
0 200 400 500 ouu v""
TIME ESEC)
FIGURE A-5 55 cottTAIrmENT PnESSURE VS TIf!E 50 45 C
E 40 wx Omaw 35 x
G.
F-zwrz 30 1.
C F-z au 25 20 15 1809 275
~
10 I
0 200 400 SCC 8CO 1C00 120:
TIME (SEC)
600.
FIGURE A-6 pp.It ARY LOOP TEt'PERATURES k
540 Ji
'/s o
)
. TIf tE j r ll, 480 e
COLD LEG OF U_l!.A. F..F.ECTED U LIT
~~*
420
_ HOT.. LEG s
360 ewa en w
E 300 COLD LEG 0F
/
3 AFFECTED U:!IT, '
Cewa-t ww 2A 0 c_
O O
J 180 120 60 1809 276 d7 OL~
I 4~
0 200 400 600 SCO c-
, e. : e.
~
FIGURE A-7 540 STEA!! GEttEMTOR TEttPEMTURES VS TI!!E 480 420 u
Ow Q
UttAFFECTED UtlIT 360.!.
w Wo H
C
&w csi 300 w
e AFFECTED UtlIT o
C M
240 _
wz We r
CW 180 _
en 120 _
60 _
1809 277 j
l 0
i L
I I
O 200 400 800 800 1000 120:
TIME ISEC1
~
s
.)
[800 e
1600 d
FIGURE B-1 m
N 14 g r-
!!Alti FEEC'.lATER r
3 FLO',l VS TIllE
- ~'
2o LL.
1200 c:w s-C 3
aw W
ICOC u.
z Cr 800 t
600 400 1809 278' 200 AFFECTED UMIT I
UtiAFF,ECTED U :IT 1
1 0
i f
i I
O 200 400 SCO 80u
'200
.-ev TIME '5:.C;
360__
FIGURE B-2 320
~~
El1ERGEflCY FEEDt!ATEi! FL0tl VS TIl1E fl0 FL0ll TO UilAFFECTED 280 UNIT b
m N
Ee d
240
=
O J
LL CCw 200 H
CC 3
O W
W O
Cd W
5 120 80.I 40 1809 279 II O ff f
i i
i 0
200 400 600 800 1000
- 20f TIME fSEC)
FIGUP.E B-3 REACTIVITY CHAi!GES VS 8
TIl1E 6
t:00ERATOR 4
~
2 H
z l
W u
I x
n W
I #
c.
D0PPLER
~
0 W
Hu 5
-2 x
____.... _=
TOTAL TOTAL
-4 i
BORO?!
.l
-6 CEA
-8 _
1809 280
-10 I
i L_
O 200 400~
600 800 1000
'20C Tite (SEC)
FIGURE 3-4 0.90
.C0RE POWER VS
, TIliE,
0.[G 0.70 0.60 0_
0.5 e
toz O
CL.
Lt.Je 0.40 oo 0.30 c-1 0_
0.2 7 0.10 r
1809 281 1
010 0 i
i I
O 200 400 600 500 000
- 200 TIME (SE01
l FIGURE B-5 55 C0t!TAlftf1EllT PRESSURE VS TIllE 50 45 N
C m
4O C.
toeam m
to 35 e
c Hz tuzz 30 E
h z
ou 25 20 i
15
~
180c) 282 10 f
O 200 400 500 800 1000 120:
TIhE (SEC1
... ~. ;r...z. =..... : --- - - -
-....----.........=:s--:_
..L"" ~~
- * ~ ~
600 3
FIGURE B-6 540 PRIllARY LCOP TEi:PERATURES
<VS
.TIIE t.
II 480 COLD LEG OF UtlAFFECTED UtlIT 420 HOT LEG '
u_
360 o
wa en a w
e
/
O 300 _
COLD LEG 0F Hg AFFECTED UtlIT, ewar
.: 1 H
2A 0 c.
Oo
_a 180 120 SC 1809 283 0
I 0
200 400 600 800 1000
'2C:
,..c,
vvv FIGURE B-7 540 STEAtt GE?lEPATOR TEl'PEPATURES VS TItt:
(
l 480,_
420 u.
ow UilAFFECTED UttIT O
360 w
e:
D F--
C CCwa.r 300 w
l-AFFECTED UtlIT n
Ce 240 wzw o
r C
W l80 tn 120 60 1809 284'-
0----
i 0
200 400 600 6en
'000
- 2c-TIME ? SEC 1
.~ ~.-.
1800 _
FIGURE C-1 itAIII FEED'.!ATER FLC'.l VS tit:E i
1600 1400 uw en 2
1200 a
1o d
100C cc W
F--
C 1
OW 80C w
u_
z Cr 600 400 -
200 AFFECTED Ui!IT 1809 285 Ut!AFFECTED U'!IT i
0 I
I J
~
0 200 400 500 SCO
'CCC
'20:
TIME (SEC1
,ve 360 FIGURE C-2 320 ECI,0C 'C'I i:CC'.;f,T C.n. FL0tt VS TI."e
}
280 tl0 FL0tl TO VilAFFECTED UllIT uW m
N=
d 240N; m
=
O
.J LL W
200 _
C 2
CW m
LL 160 u
z LA.J O
LAJ 5
120 80 40 809 286 i
0 i
-J 0
200 400 60C Sau 5000
'2C.
TIi1E (SEC
FIGURE C-3 8
REACTIVITY CHAiMES VS TIf E 6
fiODERATOR 4
[
~2 z
ta U
D0PPLER 0
F-
>-u BOR0ft c:
-2 ge
-4 TOTAL i
-6 J
J
~*
~~
i809 287 CEA
-10 I
f
___ ' I 0
200 400 600 600
'000
'2C:
TIME J5EC:
FIGURE C-4
- 0. 9 0 --
CORE POWER VS.
' TIME 0.80 ' _.
l l
0.70 0.60 0.5 0 ew 1o o_
w M
0.0 ou 0.30
~
0.20 0.10 1809 288 0
I I
I l
0*0V
~
O 200 400 SCO SCO
'000 1200 TIME ISEC1
FIGURE C-5 4
COIITAIi;;'EilT PRESSURE 55 vs TIliE 50 _
45 e
40 m
Cd
'3 mom 35 e
C.
>--zm zz 30
-e
~z O
U 25 20
~
15 l
~
1809 289-10 i
i i
i 0
200 400 SCC 80G
- 000 120
TIME (SEC1
ovu FIGURE C-6 PRIt'ARY LOOP TEf'PERATURES 540 L'
vs
[
TIftE 4
480 420 COLD LEG OF UNAFFECTED Uili.T u.
,M0T LES/
360 aw Q
w v) w Cda 300 COLD LEG OF AFFECTED U!ITj Ccw CLz w
H 240 o'
a a
180 d
120 60 _
f809 290 0
l i
I f
0 200 400 6C0 800
'CCC
'200 TIME (SEC1
6UU FIGURE C.7 STENT GEilERATOR TEMPEMTurtES 540 VS.
TIftE fu
\\
480 420
.x O
Wo UtlAFFECTED UIIIT 360 weaw C
M w
CL 300 AFFECTED g
H UtlIT e
O C
e 240 w
Z W
O r
C d
180 m
120 s
60 1809 291
O i
i i
i i
0 200 400 600 800
- CCG 12 C ':
TIME fSEC1
'JUUU FIGURE 0-1 180G
~
tiAIN FEED'..'ATEF. FLO!!
VS TIltE 1600 1400 uu
<n s
1200 a_)
~
w
=
0
_.2 u_
1000 cr:
w H
C 2ow 800 w
11.
z Cr 600 s
400 200 AFFECTED UNIT 1809 292 UNAFFECTED UNIT l.,
0 I
I 0
200 400 SCO 800
!C00
- 2C
TrM-r c.
c :
400 e
360 FIGURE D-2 320 El1ERGE! ICY FEEC!lATER FLO!!
VS TIl1E (10 FL0tl TO UilAFFECTED Uf!IT 280
_I uwm Nr 1
e J
2 4 0 c, T
=
0 a
L Mw 200 C=
Q
- 1) m L.L.
160 3u Z
uJ 0e W
5 120 80 40 k809 293 i
O I
I O
200 400 SCC 800 1000
'23.
TIMF f c, F e 1
FIGURE 0-3 REACTIVITY CHAftGES VS TIliE 8
6 liODERATOR 4
~
2 wz u;
o DOPPLER o
O W
Hu 5
- 2 '-
TOTAL x
TOTAL BOR0tl
_4
- 6,_
-8 1809 294
-10 I
I I=
I O
200 400 600 800 1000 1200 TIME (SEC1
I.U V 4
s
+
0.90 ;
1 FIGURE 0-4 CORE POWER l
VS O.80 '._
- E 0.70._
0.60 0.50 zw 2:o a.
we 0.40 ou 0.30 0.20 0.10 l'809 295
~
0.00 i
i I
O 200 400 SCO SCO 1000 1200 TIME ('S E C )
FIGURE 0-5 C0:4TAItUiEtiT PRESSURE 55 vs TItiE 50 4
45
_ f\\
c E
40 w
Cdawnw 35 cc a_
2wr 2
30 c
sz Oo 25 20 t
15 l
1809 296 1 0 I
i O
200 400 600 SCC 1000 12CC TIME fSEC1
[-
FIGURE D-6 540 p
pRIltARY LOOP TEftPERATURES V
VS
. TItiE 480
)
COLD LEG OF UttA_FfECTED _U: LIT 420 u.
HOT L_EG 360 aw C
mw c::
COLD LEG OF a
300 n
AFFECTED UtiIi,
C cc:
u 2
w
~
240 c.o a
J 180 _
120 60 1809 297 0
I r
f 0
200 400 600 800
'000
'200 TIME (SEC1
600
,4.
FIGURE D-7 540 STEArt GEtiERATOR TE?1FERATURES VS TIttE v
,v,\\
_\\
480 t
420 _
u.
U!!AFFECTED U? LIT C
360 _
wxaw C
gw c_
r 300 AFFECTED H
UtlIT e
Q H
C e
240 wz u
o r
C d
180 m
120 SC 1809 298 O
I I
I O
200 400 600 800
!CCG
'2C:
T I M.C I SE C 1