ML19253B436
| ML19253B436 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/20/1979 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 7910150685 | |
| Download: ML19253B436 (52) | |
Text
.
-q O t
[t
.m s
U Docket No. 50-346 gg License No. NPF-3 Serial No. 1-91 September 20, 1979 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Attachments A and b are Toleda Edison's follow-up responses to IE Bulletin 79-05C for the Davis-Besse Nuclear Power Station, Unit (DB-1) concerning reactor coolant pump operations. Ihese discuss the analyses and development of preliminary operator guidelines for reactor coolant pump operations.
Attac iment A is the continued evaluation of Short Term Action Item Number 2 discussed in Toledo Edison's letter of August 29, 1979 (Serial No. 1-85).
It is noted that this analysis was completed for a lowered loop reactor coolant system configuration and is a conservative evaluation for the raised loop DB-1 design.
Attachment B is a revision to Section III of the " Analysis Summary in Support of an Early RC Pump Trip" also transmitted in our August 29, 1979 letter. This revision replaces entirely the previously submitted Section III.
Very truly yours,
((
n = 7.
Richard P. Crouse Vice President - Energy Supply RPC/TJM cc:
Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 7
Os
. N Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission g
Washington, D. C.
20555 l
4
'f 115l 054 THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISOf J AVENUE TOLEDO. OHIO 43552 ~
7910150(JS
.i
't Docket No. 50-346 License No. NPF-3 Serial No. 1-91 September 20, 1979 ATTACIDIENT A SUPPLDiENTAL SMALL BREAK ANALYSIS 1151 055
f.
SUPPLEMENTAL SMALL BREAK ANALYSIS 1151 056 I.
' \\.
1 1
1.
Introduction Babcock & Wilcox has evaluated the effect of a delayed reactor coolant (RC) pump trip during the course of a small loss-of-coolant accident. The results of this evaluation are contained in Section II of the report entitled " Analysis Summary in Support of an Early RC Pump Trip."1 (Letter R.B. Davis to B&W 177 Owner's Group, " Responses to IE Bulletin 59-05C Action Items," dated August 21, 1979.)
The above letter demonstrated the following:
A delayed RC pump trip at the time that the reactor coolant system is at high a.
void fractions will result in unacceptable consequences when Appendix K evaluation techniques are used. Therefore, the RC pumps must be tripped be-fore the RC system evolves to high void fractions.
b.
A prompt reactor coolant pump trip upon receipt of the low pressure ESFAS signal provides acceptable LOCA consequences.
The following sections in this report are provided to supplement the information contained ir reference 1.
Specifically discussed in this report are:
The analyses to determine the time available for the operator to trip the a.
reactor coolant pu=ps such that, under Appendix K assumptions, the criteria of 10 CFR 50.46 would not be. violated.
b.
The RC pump trip times for a spectrum of breaks for which the peak cladding temperature, evaluated with Appendix K assumptions, will exceed 10 CFR 50.46 limits.
A realistic analysis of a typical worst case to demonstrate that the conse-c.
quences of a RC pump trip at any time will not exceed the 10 CFR 50.46 limits.
2.
Time Available for RC Pump Trip Under Appendix K Assumptions A spectrum of breaks was analyzed to determine the time available for RC pump trip under Appendix K assumptions. The breaks analyzed ranged from 0.025 to 0.3 ft2 As was demonstrated in reference 1, the system evolves to high void frac-tions early in time for the larger sized breaks.
Values in excess of 90% void 2 break.
For the fraction were predicted as early as 300 seconds for the 0.2 ft smaller breaks it takes much longer (hours) before the system evolves to high void fraction. Therefore, the time available to trip the RC pump is minimum for the larger breaks. However, as will be shown later, for the larger small breaks
(>0.3 ft ), a very rapid depressurization is achieved upon the trip of RC pumps 2
at high system void fraction. This results in early CFT and LPI actuation, and i15l 057
a subsequent rapid core refill. Thus, only a small core uncovery time will The following paragraphs will discuss the available time to trip the RC ensue.
pumps for differcat break sizes.
In performing this evaluation, only one HPI systen was oscuned available rather than the two HPI systems assumed in the ref-erence 1 analyses, Break - Figures 1 and 2 show the system void fraction and available 2
a.
0.3 ft liquid volume in the vessel versus time for RC pump trips at 95, 83, and 63%
2 break at the RC pump discharge. For the pump void fractions for a 0.3 ft trip at 95% void the system void fraction slowly decreases and then it drops faster following the CFT and LPI actuations. Following the RCP trip, the The core begins pressure drops rapidly and CFT is actuated at 250 seconds.
to refill at this time and, with LPI actuation at 300 seconds, the core is flooded faster and is filled to a liquid level of 9 feet (equivalent to The total core un-approximately 12 feet swelled mixture) at 370 seconds.
covery time is 170 seconds. Assuming an adiabatic heatup of 6.5*F/sec, as explained in reference 1, the consequences of a RC pumn trip at 95% void will not exceed the 22000F limit.
the As seen in Figure 2 for the RC pump trip at 63% or lower void fractions, available liquid in the core will keep the core covered above the 11 feet elevation for about 350 seconds, and above 12 feet elevation at all other Therefore, tripping the RC pumps at void fractions s 63% will not times.
result in unacceptable consequences as the core will never uncover.
A RC pump trip at 83% void fraction demonstrates an uncovery time of 350 However, previous detailed small break analysis (reference 2) have seconds.
shown that a 10 ft of mixture height in the core will provide sufficient core cooling to assure that the criteria of 10 CFR 50.46 is satisfied.
For this case, the 10 feet of mixtu-e height is provided by approximately 1600 ft3 liquid in the vessel. At this level in Figure 2, the core uncovery time is 220 seconds. Again, even with the assumption of adiabatic heatup It should be pointed over this period, the consequences are acceptable.
out that if credit is taken for steam cooling of the upper portion of the fuel pin, the resulting PCT will be significantly lower then that obtained from the adiabatic heatup assumption.
Fr?m Figure 2, it can be concluded that a RC pump trip at 120 seconds will For RC pumps trip at system void fractions result in little core uncovery.
1151 058
~
5 t
higher than 95% (at 200 seconds), the system will be at a lower pressure and with the CPT and LPI actuation there will be little or no core uncovery.
Although core uncoveries are predicted for trips at 83% and 95% system void fractions, as shown earlier, the consequences are acceptable.
Thus, a de-layed RC pump trip at anytime for this break will provide acceptable conse-quences even if Appendix K evaluation techniques are used.
For breaks larger than 0.3 ft2, a delayed RC pump trip at any time during the transient is also acceptable as the faster depressurization for these breaks will result in smaller delays between the pump trip and CFT and LPI actuation. Therefore, core uncovery times will be smaller than that shown for the 0.3 ft2 break.
b.
0.2 ft2 Break - Figures 3 through 5 show the system void fraction and avail-able liquid volume in the vessel versus time for RC pump trips at 98, 73, 60 and 45% void fraction for a 0.2 ft2 break at the RC pump discharge.
As seen in Figure 5, the RC pump trip at 45 and 60% void fraction does not re-sult in core uncovery. The available liquid volume is sufficient to keep the core covered above the 10 ft elevation at all times.
For the trip at 98% void fraction in Figure 4, the core is refilled very rapidly with the actuation of CFT and LPI at approximately 420 and 450 seconds, respectively.
The core is refilled to an elevation of 9 feet at 460 seconds. The core un-covery time is in the order of 60 seconds, and the consequences are not sig-nificant. The RC pump trip at 73% void fraction as seen in Figure 4, re-sults in a 450 seconds core uncovery time. Although a 450 seconds uncovery time seems to result in unacceptable consequences, if credit is taken for steam cooling and using the same rationale as that given for the RC pump trip at 83% system void in section 1.a. it is believed t, hat the consequences will not be significant.
Should the RC pumps be tripped at system voids less than 70%, there vill be little or no core uncovery. However, for void fractions between 73% and 98%, there is a potential for a core uncovery depth and time which might be unacceptable. Thus, a time region can be de-fined in which a RC pump trip, evaluated under Appendix K assumptions, could result in peak cladding temperatures exceeding the 10 CFR.50.46 cri-
~
teria. This window is narrow and extends from 180 seconds (73% void) to 400 seconds (98% void) after ESEAS. A RC pump trip at any other time will not result in unacceptable conbequences.
(
o 1151 059
c.
0.1 ft2 Break - Figures 6 and 7 shows system void fractions and available liquid volume for trips at 90, 60, and 40% system void fractions for a 0.1 ft2 break at the RC pump discharge.
The same discussions as those presented in sections 2.a and 2.b can be applied here. However, due to slower depres-surization of the system for this break, complete core cooling is not pro-vided until the actuation of LPI's.
As seen in Figure 7, the time to trip the RC pumps without any core uncovery is approximately 250 seconds.
In Figure 6, with the RC pumps operating the LPI's are actuated at approximately 2350 seconds.
Tripping the RC pumps at any time before 2350 seconds will actuate the LPIs earlier in time. Therefore, unacceptable consequences are predicted for a delayed RC pump trip in a time range of 250 seconds to 2350 seconds.
For any other time, all the consequences are acceptable.
d.
0.075, 0.05 and 0.025 ft2 Breaks - Figures 8 and 9 show a comparison of system void fractions for pumps running and pumps tripped 3 conditions. As seen in Figure 8, with the RC pumps tripped coincident with the reactor trip, in the short term, the evolved system void fraction is greater than that with the RC pumps operative. The two curves cross at about 300 seconds.
Before this time, a RC pump trip will not result in unacceptable consequences since the system is at a lower void fraction than RC pumps trip case. There-fore, the time available for RC pumps trip with acceptable results is esti-mated at 300' seconds. As the system depressurizes and LPI's are actuated, the core will be flooded, and a RC pump trip after this time will have ac-ceptable consequences.
From the analyses performed, the LPI actuation time is estimated at approximately 3000 seconds.
Therefore, the region between 300 and 3000 seconds defines the time region in which a RC pump trip could result in unacceptable consequences.
For a 0.05 ft2 break, the same argument can be made using Figure 9.
As seen from this figure, the time available to trip the RC pumps is approximately 450 seconds.
The LPI actuation time for this break size is estimated at approximately 4350 seconds. Therefore, the unacceptable times for RC pump trip is defined between 450 and 4350 seconds.
As discussed in reference 1, the system evolves to high void fractions very slowly for 0.025 ft2 or smaller breaks. The system depressurization is very slow and it takes on the order f hours before the LPI's are act.uated. A RC pump trip at 2400 seconds for the 0.025 ft2 break results in a system l!51 060
t void fraction below 50% and the core remains completely covered. A study of the 0.025 ft break with 2 HPI's available shows with the RC pumps op-2 erative the system void fraction never exceeds 61%. The CFT is actuated at approximately 4800 seconds and the system void starts to decrease and available liquid volume in the RV starts to increase. Thus, the core will remain completely covered for any RC pump trip time and, thus, will result in acceptable consequences. With one HPI available, a slower depressuriza-tion is expected but the system evolution to high void fraction will still be very slow. Thus, the conclusion that a RC pump trip at any time yields 2
acceptable consequences for the 0.025 ft break holds whether one or two HPI's are assumed available.
2 break can be extrapolated using The LPI actuation time for the 0.025 ft the available data of the other breaks.
Figure 10 shows the extrapolated LPI actuation time at approximately 8000 seconds. Thus, a conservative unacceptable time region for punp trip can be defined between 2500 and 8000 2
seconds for the 0.025 ft break under Appendix K assumptions.
3.
Critical Time Window for RC Pumps Trip As discussed in section 2, there is a time region for each break size in which the consequences of the RC pump trip could exceed the 10 CFR 50.46 LOCA limit.
These critical time windows were defined in section 2.
Figure 11 shows a plot of the break size versus trip time RC pump which results in unacceptable conse-
" e region indicated by dashed lines represent a boundary in which quences.
unacceptable consequences may occur if the RC pumps are tripped. However, this region is defined using Appendix K assumptions.
It should be recognized that this region, even under Appendix K assumptions, is smaller than what is shown in Figure 11 as the 0.2 and 0.025 ft breaks may not even have an unacceptable 2
region. The time available to trip the RC pumps can be obtained from the lower bound of this region and is on the order of two to three minutes after ESFAS.
4.
" Realistic" Evaluation of Impact of Delayed RC Pump Trip for a Small LOCA
.a.
Introduction As discussed in the previous sections, there exists a combination of break sizes and RC pump trip times which will result in peak cladding temperatures in excess of 2200F if the conservative requirements of Appendix K are utilized in the analysis. The analysis discussed in this section was performed utilizing
" realistic" assumptions and demonstrates that a RC pump trip at any time will not result in peak cladding temperatures in excess of the 10 CFR 50.46 criteria.
t i151 061
e.
b.
Method of Analysis There are three overriding conservatisms in an Appendix K small break evalua-tion which maximizes cladding temperatures. These are:
(1) Decay heat must be based on 1.2 times the 1971 ANS decay heat curve for in-finite operation.
(2) Only one HPI pump and one LPI pump are assumed operable (single failure cri-terion).
The local (3) The axial peaking distribution is skewed towards the core outlet.
heating rate for this power shape is assumed to be at the LOCA limit value.
In performing a realistic evaluation of the effect of a delayed RC pump trip following a small LOCA, the conservative assumptions described above were modi-fied. The evaluation described in this section utilized a decay heat based on 1.0 times the 1971 ANS standard and also assumed that both HPI and LPI systems were available. The axial peaking distribution was chosen to be representative of normal steady-state power operation.
Figures 12 and 13 show the axial peaking distributions utilized in this evalua-tion.
These axial distributions were obtained from a review of available core follow data and the results of manuvering analyses which have been performed for the operating plants. A radial peaking factor of 1.651, which is the maxi-mum calculated radial (without uncertainty) pin peak during normal operation, was utilized with these axial shapes. As such, the combination of radial and worst axial peaking are expected to provide the maximum expected kw/ft values for the top half of the core for at least 90% of the core life.
Since the worst case effect of a delayed RC pump trip is to result in total core uncovery with a subsequent bottom reflooding, maximum pin peaking towards the upper half of the core will produce the highest peak cladding temperatures. Thus, this evaluation is expected to bound all axial peaks encountered during steady-state power operation for at least 90% of core life.
2 The actual case evaluated in this section is a 0.05 ft break in the pump dis _
charge piping with the RC pump trip at the time the RC system average void fraction reaches 90%. As discussed in reference 1, RC pump trips dt 90% syetem void fraction are expected to result in approximately the highest peak cladding The CRAFT 2 results for this case and the evaluation techniques temperatures.
utilized are discussed in section II.B.5 of reference 1.
A realistic peak i151 062
cladding temperature evaluation of this case, which is discussed below, is ex-pccted to yield roughly the highest peak cladding temperature for any break size and RC pump trip time. As shown in reference 1, uaximum core uncovery times of 2
approximately 600 seconds occur over the break size range of 0.05 ft through 2 and 0.1 ft2 using 1.2 times the ANS curve. Break sizes smaller than 0.05 ft 2
larger than 0.1 ft will yield smaller core uncovery times as demonstrated in reference 1 and the preceeding sections.
Use of 1.0 times the ANS decay heat curve would result in a similar reduc. 7 in core uncovery time, approximately 2
200 seconds, for breaks in the 0.05 through 0.1 ft range.
Thus, the core re-2 fill rate, uncovery time, and peak cladding temperatures for the 0.05 ft case is typical of the worst case values for the break spectrum, c.
Results of Analysis 2
Figurs 14shows t ie liquid volume in the reactor vessel for the 0.05 f t break with a RC pump trip at the time the system average void fraction reaches 90%.
The core initially uncovers and recovers approximately 375 seconds later. Using the previously discussed realistic assumptions the peak cladding temperature for this case is below1900F.
Therefore, the criteria of 10 CFR 50.46 is met.
The temperature response given above was developed in a conservative manner by comparing adiabatic heat up rates to maximum possible s:.eady-state cladding temperatures.
First, a temperature plot versus time is made up for each loca-tion on the hottest fuel assembly assuming that the assembly heats up adiabati-4 cally.
Second, a series of FOAM runs are made to produce the maximum steady-state pin temperatures at each location as a function of core liquid volume.
FOAM calculates the mixture level in the core and the steaming rate from the portion of the core which is covered.
Both the mixture height and steaming rate calculations are based on average core power. Fluid temperatures in the uncovered portion of the fuel rod are obtained by using the calculated average core steaming rate and by assuming all energy generated in the uncovered portion of the hot rod is transferred to the fluid.
The surface heat transfer coaffi-5 cient is calculated, based on the Dittus-Boelter correlation, from the fluid temperature and steaming rate and the steady-state clad temperature is obtained.
The FOAM data are then combined with the core liquid inventory history (derived from Figure 14.) to produce a maximum possible cladding temperature as a function of time. This graph might be termed ma imum steady-state cladding temperature as a function of time and decreases in,value with time because the core liquid 1151 063
inventory is increasing.
By c oss plotting the adiabatic heat up curve with the maximum steady-state curve a conservative peak cladding temperature predic-tion is obtained.
5.
Conclusions From this analysis, and the results in reference 1, the following conclusions have been drawn:
Using Appendix K evaluation techniques, there exists a combination of break a.
size and RC pump trip times which result in a violation of 10 CFR 50.46 limits.
b.
Prompt tripping of the RC pumps upon receipt of a low pressure ESEAS signal will result in cladding temperatures which meet the criteria of 10 CFR 50.4'y.
The minimum time available for the operator to perform this function is 2 to 3 minutes.
c.
Under realistic assumptions, a delayed RC pump trip following a small break will result in cladding temperatures in compliance with 10 CFR 50.46.
115l 064
/
e
REFERENCES,
" Analysis Summary in Support of an Early RC Pump Trip,"Section II of letter
~
1 R.B. Davis to B&W 177 Owner's Group, Responses to IE Bulletin 79-05C Action Items, dated nagust 21, 1979.
Letter J.H. Taylor (B&W) to Robert L. Baer, dated April 25, 1978.
2 3 Letter J.H. Taylor to S.A. Varga, dated July 18, 1978.
B.M. Dunn, C.D. Morgan, and L.R. Cartin, Multinode Analysis of Core Flooding 4
Line Break for B&W's 2568 MWt Internals Vent Valve Plants, BAW-10064, Babcoc}
& Wilcox, April 1978.
R.H. Stoudt and K.C. Heck, THETAl-B - Computer Code for Nuclear Reactor Core 5
Thermal Analysis - B&W Revisions to IN-1445, (Idaho Nuclear, C.J. Hocevar and T.W. Wineinger), BAW-10094, Rev. 1, Babcock & Wilcox, April 1975.
1151 065 e
b
t 2
Figure 1 : 0.30 FT BREAK e P.D., SYSTEM VOID FRACTION VS TIME 100
~~'%
/
y f,0 0
~Oe lW A.ue Om O-1..* = w - ~ m x 80 n
I 4.l I/
R V
PUMPS RUNNING u.
v 60 I
Y f
PUMPS OFF @ 95% VOID I
e B
I I
PUMPS OFF e 83% VOID N
40
-O I I
I l
-y-x PUMPS OFF e 63% VOID 20 0
i e
i i
i O
200 400 600 800 1000 T1me, sec
.1 o
1151 066
Figure 2: 0.30 FT2 BREAK @ P.D.,AVAILABLE LIQUID VOLUME IN RV VS TIME, 1 HPI AVAI!43LE s
3000 O
M*
a
/
8
$3-~/
/[
/
o ci 4q S M
e; 2
/*!
1 5
4
/
h \\
/
2 W. I
[f u
2000 p-bX7 x#
LIQ. LEVEL AT TOP OF CORE y
3 A
i J
l 1__
o Y
'[Sof LIQ. LEVEL AT 9 CORE ELEVATION M
If So A
A
[I
~
II I
a y ji l
PUMPS OFF e 95% VOID 1000 l \\ I o
x s
y l
-o-o-PUMPS OFF @ 83% VOID I
S g
-x-y PUMPS OFF @ 63% VOID E
I h
I a-t Iv O
0 400 800 -
1200 1600 2000 Time, sec 1151 067
2 Figure 3 : 0.20 FT BREAK e P.D., SYSTEM VOIO FRACTION VS TIME 100 -
f,- o-o s,**-
,s 8
t g
I hl 9
s I
$#N%
t E
I
- g Jor i
/h g
. ~,
g
,,+
\\
I 70
\\
l
\\
i N
i z
I*
s t,
'g 60 p
y a
f n.
8 PUMPS ON gf 50
.......... PUMPS OFF e 98% VOIO Pr
-x x- -XX-PUMPS OFF e 73% VOIO 40 PUMPS OFF e 60% VOIO
-X X-PUMPS OFF e 45% VOIO 30 20 0
400 800 1200 1600 2000 Time, sec IISI 068
t 2 BREAK e P.O.,AVAILABLE LIQ. VOL.
Figure 4 : 0.20 FT IN RV VS TIME 1 HPI AVAILABLE 3000 S
S
/
/
9 9
m n
I 0
y
, f
/
n b
e Sv /
xx m
r r
f-h h
l M
i e
e l
/
-x a
2000 I
LIQ. LEVEL AT TOP OF CORE
,o
\\
3 x
2
/
LIQ. LEVEL AT 9' CORE ELEVATION f
k l
4 i
.s i
/
- - - PUMPS OFF e 98% VOIO a
'[
F j
N y
1
-X-X-PUMPS OFF e 73% VOIO 4
3 I
1000 g
i l
l l
i I
i I
i 1
0
.I 0
400 800~
1200 1600 2000 Time, sec 1151 069
2 BREAK e P.D. AVAILABLE LIQ. VOL.
Figure.5 0.20 FT IN RV VS TIME 1 HPI AVAILABLE 3200 -
3000 I
- W- -x- -x PLNPS OFF e 2800 I
45% VOID
\\
PUMPS OFF e E
I a
60% VOIO g
g 2600
.R a
i 3
i
(
e I
2400 N
\\
A
\\
\\
2200 I
\\
/
I
/
\\
4 2000 y___/
y LIQ. LEVEL e TOP OF CORE Ny 1800 LIQ. LEVEL AT 9' CORE ELEVATION 1600 e
i O
400 800 1200 1600 2000 Time, sec 115l 070 WW N,9W -
wi-,
-,y,=
n.
Figure 8 : 0.1 FT2 BREAK 9 P.D.,AVAILABLE LIQUID VOLUME
- IN RV VS TIME, 1 HPI AVAILABLE s%
3000
\\
\\
\\
\\
/
f o'
o s
s i
9 9 A\\
/
4\\
\\
t x
a
@ '+
\\,
g g
s o
e e
E S t
\\
l
\\
m t
E E
- \\
t s
o..
s
\\
2000 l
\\+
g s'
o as
~~~____p LIQ. LEVEL e l
ua
.+\\
S 9' ELEVATION l
o l
+\\M-g gw3*j##
j I
a Io 1TO l
S j
-o-o-PUMPS OFF 9
{
e 90% VOID o
-X-X-PUMPS OFF e 60% VOIO
/o e
PUMPS OFF o
n.
h
/
e 40% VOID S
~o\\ o,o eg o_,
[..'
O i
i i
0 400
.800 1200 1600 2000 Time, see h$Nl 0l}
Figure 7 : 0.1 FT2 BREAK e P.D., SYSTEM VOID FRACTION VS TIME LPI 100 l
p:::gr-nc-r.y - - - - - ~ -
/
h l\\
ae 80
/
j./
s g
g'
/
- ej ;~'
s o-o
/ /
,o'o
,,o**,,,.
I
\\
p
/
o 3
\\
N /
60 l
5 l'/
O PUMPS RUNNING
.E x x PUMPS TRIP e 90% VOID i
40 o
l
-.-PUMP TRIP e 60% VOID 1
/
-o-o PUMP TRIP e 40% VOID 20 0
I i
i O
500 1000 1500 2000 2500 Time, sec 4
1151 072
Figure 8 : SYSTEM V010 FRACTION VERSUS TIME g.1 9-6
/
40 -
%g
/
9
%f
/
35
/
3/
30
.s%
&/
g/
Af
&7 25 s+ /
_5 s%7 5
20 R/
/
/
A = ESFAS ON
/
15 a
10 d
5 0
O 50 100 150 200 250 300 Time, sec O
1.151 073
Figure 9 : SYSTEM V010 FRACTION VERSUS TIME PUMPS RUNNING AND PUMPS TRIPPE0 MODEL 40 Q
3 4
q-35 E
4 Q
30 p*p-S
-4 /
,0 a
20 E
15 A = ESFAS ON 10 f
5 0
O 100 200 300 400 500 Time, sec I151 074 i
u>
n c.
-4 Figure 10 : BREAK SIZE VS LPI ACTUATION TIME
[
0.4 N
[
0.3 i
N m
2
@ 0.2 m
0.1 EXTRAPOLATED LPI. FOR 0.025 BREAK 1
e a
O 1000 2000 3000 4000 5000 6000 7000 8000 9000 Time, sec 9
Figure 11 : CRITICAL REGION FOR HC PUMPS TRIP, BREAK SIZE VS TIME O.3 b
i_5N m
t
\\~ ~ \\ N
\\
s j 0.2 is a
w CRITICAL REGION NOTE:
TIME T = 0.IS REACTOR TRIP TIME 0.1 en o
sq w
i i
....i 0
..ii..
l0000 100 1000 TW m
Figure 12 : " REALISTIC" CORE AXIAL PEAKING DISTRIBUTION-CASE 1 1.6 1.4 x
E a.
a 1.2 3
X*
1.0 Fu
.M s
0.8 E
az 0.6 0.4 0.2 tn 0
i i
e i
i c3 0
20 40 60 80 100 120 140 160
.~ 4 Core Ht., in sa
i i
m N
ca 6
Figure 13
" REALISTIC" CORE AXIAL PEAKING DISTRIBUTION-CASE 2 LO
~
N 1.6 g 1. 4 E'
g 1.2 0
< 1.0 A 0.8
' ~ ~ '
E r
8 f
z 0.6 t
0.4 i
t, 0.2 0
0 20 40 60 80 100 120 140 160 Core Elevation (inches) e e
Figure 14 : AVAILABLE LIQUID VOLUME VS TIME 2 BREAK WITH 1.0 ANS FOR 0.05 FT DECAY CURVE 3000 u-2500 ci 5s O
R 9
3 2000 LIQ.LEVELeCOREh j
9' ELEVATION 1500 E5 v>
an.
O" 1000 500 1600 1800 2000 2200 2400 2600 Time, sec e
e e
llSi 079
Docket No. 50-346 License No. NPF-3 Serial No. 1-91 September 20, 1979 ATTAC11 MENT B IMPACT ASSESSMENT OF A RC PUMP TRIP ON NON-IDCA EVENTC 1I51 080
' 99-as c
% V77 LA M.1IUPACT ASSESS!!E"T OT A IC PUMP T):7P 0" !!ON-LOCA EVD:TS III.
A.
Introduction Some Chapter 15 cvents are characterized by a primary system The Section 15.1 response similar to the one following a LOCA.
events that result in an increase in heat removal by the secondary system cause a primary system cooldown and depresnurization, much like a small break LOCA. Therefore, an asressment of the conse-quences of an imposed RC puup trip, upon initiation of the low RC pressure ESF/.S, was made for these events.
of Pu,p Trip in Non-LOCA Events B.
General Assessment that Several concerns have been raised with regard to the eff ect exhibit LOCA an carly pu=p trip would have on non-LOCA events that Plant recovery would be more dif ficult, dependence, characteristics.
on natural circulation mode while achieving cold shutdown wo*uld be highlighted, manual fill of the steam generators would be required, However, all of these drawbacks can be accommodated since and so on.
- Also, none of them will on its own lead to unacceptabic consequences.
restart of the pumps is recommended for plant control and cooldown Out of this scarch,
'once controlled operator action is assumed.
three najor concerns have durfaced which have appeared to be sub-stantial enough as to require analysis:
A pu=p trip could reduce the time to system fill /repressurization 1.
If or safety valve opening following an overcooling transient.
the time availabic to the operator for controlling HPI flow and the margin of subcooling were substantially reduced by the pump trip to where timely and effective operato,r action could be questionable, the pump trip would become less desirabic.
In the event of a large steam line break (maximb overcooling), the 2.
blevdown may induce a steam bubble in the RCS which could impair natural circulation, with severe consequences on the core, es-pecially if any degree of return'to power is experienced.
A more gencral concern exists with a large steam line break at EOL 3.
conditions and whether or not a return to power is experienced If a return to critical is experienced, following the RC pump trip.
natural circulation flow may not be suf ficient to remove heat and to avoid core damage. ll51 (J81
\\
j
Owerheating events were not considered in the impact of the RC puanp trip since they do not initiate the low RC pressure ESFAS, In addi-end therefore, there would be no coincident pump trip.
i tion, these events typically do not result in an c=pty pressur zer Reactivity or the formation of a steam bubble in the primary system.
In addi-transients were also not considered for the same reasons.for tion, for overpressurization, previous analyses have shown that the worst case conditions, an RC pump trip will mitigat_e the precourc This results from the greater than 100 psi reduction in rise.
pressure at the RC pump exit which occurs after trip.
Analvsis of Concerns and Results_
C.
System Renressurization 1.
In order to resolve this concern, an analysis was perforced for a 177 FA plant using a MINITRAP m.odel based on the case Figure 3.1 shows the noding/ flow path set up for TMI42, scheme used and Tabl,c20 provides s description of the nod and flow paths. This case assumed that, as the result of a s=all stea= line break (0.6 ft, split) or of some combination of - aondary side valve f ailure, secondary side heat demand This increase was increased from 100% to 138% at time zero.
in secondary. side heat dc=and is the smallest which results in a (high flux) reactor trip and is ;'ery similar to the worst moderate frequency overcooling event, a failure of the In the analysis, it was assumed steam pressure regulator.
that following EPI actuation on low RC pressure ESFAS, main and the auxiliary feedwater is ramped down, MSIV's shut, This action was feedwater initiated with a 50-second delay.
taken to stop the cooldown and the depressurization of the system as soon as possible af ter EPI actuation, in order to minimize the time of refill and repressurization of the Both HPI pumps were assumed to function.
system.
The calculation was performed twice, once assuming two of the four RC pumps running (one loop), and once assuming RC pump The analysis shows that the trip right after HPI initiation.
In system behaves very similarly with and without pumps.
both cases, the pr.essurizer refills in about 14 to 16 ninutes from initiation of the transients, with the natural circula-1151 082 -
w MW
tion case refilling about one minute before the case with two of f our pumps running (Sce Figures 3.2,3.3). In both cases, the system is highly subcooled, f rom a minimum of 30*F to 120*F and increasing at the end of 14 minutes (ref er to Figure 3.4).
It is concluded that an RC pump trip following ILPI actuation increase the probability of causing a LOCA through will not the pressurizer code safeties, and that the operator will have ac well as a large margin of subcooling, to the same lead time, Although no case control HPI prior to saf ety valve opening.
with all RC pu=ps was made, it can be inf erred f rom the one loop case (with pu=ps running) that the subcooled margin will The be slightly larger for the all pumps running case.
should do so by 16 pressuriser will take longer to fill but minutes into the transient. Figure 3.t shows the coolant temperatures (hot leg, cold leg, and core) as a function of time for the 3 RC pumps case.
Bubhbc on Natural Circulation Cooling 2.
Effect of Ster:
For this concern, an analysis was perf ormed f or the same assuming that generic 177 FA plant as outlined in Part 1, but DER), the as a result of an unmitigated large SLB (12.2 f t.
excessive cooldown would produce void f orcation in the primary The intent of the analysis was to also show the system.
As ir extent of the void formation and where it occ trred.
the case analyzed in Part 1, the break was symmetric to both Benerators such that both would blow down equally, caximizing break on each the cooldown (in this case there was a 6.1 ft.
There was no MSIV -losure during the transient on loep).
either steam generator to maxim!ze cooldown.
Als o,,
the tur-bine bypass system was assumed to operate, upon rupture, until isolation on ESFAS.
ESFAS was initiated on low RC pressure and also actuated HPI (both pumps), tripped RC The AFU pumps (when applicabic) and isolated the 11FWIV's.
^
was initiated to both generators on the low SC pressure signal, with minimum delay time (both pumps operating).
This ana ysis was performed twice, once assuming all RC pumps running, once with all pumps being tripped on the !IPI In actuation (after ESFAS), with a short (s5 second) delay.
both cases, voids were formed in the hot legs, but the dura-
- U51 083
tion and cize were smaller for the case with no RC pump trip (refer to Figure 3.7).Althouch the RC pu:np operatir.g case had a higher cooldown rate, thcre was less void forma-The tion, result:ng f rom the additional system mixing.
coolant temperatures in the pressurizer loop hot and cold legs, and the core, are shown for both cases in Tigures 3.5, The cere outlet pressure and SG and pressurizer 3.6.
levels versus time are given for both cases in Figures 3.S, 3.9.
This analysis shows that the system behaves similarly with and without pumps, although maintaining The RC pump flow does seem to help mitigate void formation.
pu=p flow case shows a shcrter time to the start of pres-surizer refill than the natural circulation case (Figure 3.9),
although the ti=c dif f erence does not seem to be very large.
Since the volume of the hot Icg locp above the lowest point in the candy cane portion is about 63 cubic feet, these steam fgrmatiens Icg have the potential for blocking natural circulation in the hot As a result of these findings and sinec TRAP had not been loops.
programmed to closely follow this specific condition, an additional It is based on the unmitigated 12.2 f t steam TRAP case was run.
line break with RC pump trip, since this case represented the bound-ing event for steam formation. This case included a more detailed noding schene and conservative bubble rise velocities (5.0 f t/sec) to the upper regions of the hot legs such that the effect of steam fomation on natural circulation in the loops could be observed.
The noding and flow path scheme used in this model is shown in Figure 3.10.
Table 3.2 provides a description of these nodes and flow paths. Figure 3.11 details the hot leg - candy cane -
upper steam generator shroud noding and flow path model superimposed over a scaled figme of those regions. The flow path positions anu sizes were carefuCy chosen to allow for countercurrent steam and This model is consistent liquid flow at the tcp of the candy cane.
with that used for the small break LOCA analyses descr9.ed in Sec-tion 6.2.4.2 of Ref. 5.
The results of this analysis showed steam formation only in the pressurizer loop (refer to Figure 3.12).
These steam d umes are ince they include all of the steam that vac calculated conservative r,
as being entrained as bubbles in the liquid. The additional steam volumes calculated for this loop, compared with those shown in Figure 3.7, are due to the additional boiling and steam separation that occurs in the candy cane as the liquid flow rates are reduced by steam formation and aided by metal heating., The lack of steam forma-
~
tion in the non-pressurizer loop 'B' is attributed to a correction in the metal heat transf er and metal heat capacities calculated f or the hot 1 cgs. The previous analysis erroneously included half of the steam generator tubes, based on the calculations from the ECCS Since the TRAP code aircady accounts for the tube metal CRAFT model.
in its steam generator model, this represented an unnecessary conser-vatism and it was deleted f rom the model for this case.
This case showed that the natural circulation flow was temporarily reduced. This flow reduced
_in the pressurizer loop to 45 to 100 lb/sec from 250 to 360 seconds (refer to Figure 3.13), with flow steadily increasing after this time period. The flow in the 10CD 1b/sec non-pressurizer loop remained relatively unchanged at about (ref er to Figure 3.14). Core flow was maintained from 1000 to 2000 lb/sec and no void fomation occurred (ref er tc Figures 3.15 and 3.16). The steam bubble was collapsed, natural circulation fully restored, and a greater than 50*F subcooled margin achicu.d in the pressurizer loop (refer to Figure 3.16).
Both steam generators and the pressurizer established level and the system pressure was turned cround from the HPI flow by 14 minutes into the transient (refer to Figures 3.17 and 3.18).
3.
Effect of Return to Power There was no return to power exhibited by any of the BOL cases analyzed above. Previous analysis experience (ref. Midland FSAR, Seetion 15D) has shown that a RC pump trip will mitigate the consequences of an EOL return to power condition by reducing the cooldown of the primary system. The reduced cooldown substan-tially increases the subcritical margin which, in turn, reduces or eliminates return to power.
D.
Conclusions and Summary A general assessment of Chapter 15 non-LOCA even'to identified three areas that warranted further investigation for impact of a RC pump trip on ESFAS low RC pressure signal.
It was found that a pump trip does not significantly shorten the time 1.
to filling of the pressurizer and approximately the same time interval for operator action exists.
)131 085 g
2.
For the maximum overcooling case analyzed, the RC pump trip increased the amount of void f'ormation in the hot leg ', candy canc' of the pressurizer loop; however, natural circulat' ion was not completely blocked. The steam bubble was collapsed and full natural circulation was restored. Core cooling was maintained throughout the transient and no void formation occurred in the core.
3.
The suberitical return-to-power condition is alleviated by the RC rump trip case due to the reduced overcooling effect.
e Based upon the above assessment and analysis, it is concludcd that the consequences of Chapter 15 non-LOCA events are not increased due to the addition of a RC pump trip on ESFAS low RC pressure signal, for all 177 FA lowered loop plants. Although there were no specific analyses performed for TECO, the conclusions drawn from the analyses for the lowered loop plants are applicable.
1151 086 e
e O S 4
e
-19a-
HINITRAP2 NODE DESCRIPTION NODE NU!!BER DESCRIPTION Reactor Vessel, Lower Plenum 1
Reactor Vessel, Core 2
Rea. or Vessel, Upper Picnum 3
Hot Leg Piping and Upper S. G. Shroud 4,10 Primary, Steam Generator Tube Region 5-7,11-13 Cold Leg Piping 8,14 Reactor Vessel Downconer 9
Pressurizer 15 Steam Generator Downcomer 16,24 Stcas Generator Lower Plenum 17,25 secondary, Stec= Generator Tube Region 18-20,26-28 Stcan Riscrs 21,29 Main Steam Piping 22,30 Turbine 23 Containment 31 MINITRAP2 PATH _ DESCRIPTION DESCRIPTION PATH NUMBER Core 1
Core Bypass 2
Upper Plenum, Reactor Vessel 3
Hot Leg Piping 4,11 Hot Leg Piping and Upper S. G. Shroud 5,12 6,7,13,14 Primary, Steam Generator RC Pumps 8.15 Cold Leg Piping 9,16 Downcomer, Reactor Vessel 10 Pressurizer Surge Line 17 Steam Generator Downcomer 18,19,26,27 secondary, steam Generator 20,21,28,29 Aspirator 22,30 T
Steam Riser, Steam Generator 23,31 Main Steam Piping 24,32 Turbine Piping 25,33 Break (or Leak) Path 34,35 HPI 36,37 AFW 38,39,43,44 Main Feed Pumps 40,41 LPI 42 Tabic 3.1.
1151 087
MINITRAP2 NODE DESCRIPTION DESCRIPTION NODE NUMBER o
Reactor Vessel, Lower Plenum 1
Reactor Vessel, Core 2
Reactor Vessel, Upper Plenum Hot Leg Piping (including ' Candy Cane')
3 4,10
' Candy Cane' and Upper S. G. Shroud 32,33 Primary, Steam Generator Tube Region 5-7,11-13 Cold Leg Piping 8,14 Reactor Vessel Downcomer 9
Pressurizer 15 Steam Generator Dowrcomer 16,24 Steam Generator Lower Plenum 17,25 Secondary, Steam Generator Tube Region 18-20,26-28 Steam Risers 21,29 Main Steam Piping 22,30 Turbine 23 Containment 31 MINITRAP2 PATH DESCRIPTION DESCRIPTION PATH NUMBER Core 1
Core Bypass 2
Upper Plenum, Reactor Vessel 3
Hot Leg Piping 4,11 Upper Steam Generator Shroud 5,12 Top of Hot Leg ' Candy Cane' 45,'46,47,48 Primary Heat Transf er Region, S. G.
6,7,13,14 RC Pumps 8,15 Cold Leg Piping 9,16 Downcomer, Reactor Vessel 10 Pressurizer Surge Line 17 Steam Generator Douncomer and Plenum 18,19,26,27 Secondary Heat Transfer Region, S. G.
20,21,28,29 Aspirator 22,30 Steam Riser, Steam Generator 23,31 Hain Steam Piping 24,32 Turbine Piping 25,33 Break (or Leak) Path 34,35 HPI 36,37 AFW 38,39,43,44 Main, Feed Pumps 40,41 LPI 42 1151 088 Table 3.2
-23a-
l
'W 6
,v
~-V<
A a
r.~~.~~~~.
M l
3r j
g.
3o
..... _ _......... -... -- -. q'
'r-----------~-----~~~~~
b O
jg.,f PADV g
1 Etnov-4+
1 e
mvh 15 Q
- ll e1.w N-y g
S Jo pg y
e(>
e.
~e e.i s
4 g-
,e o
g, L
J L
6 m
37 l2.
O*
O Ib M
5 e
--e.
G CIT a
3
o.) 2f 6
L 15 ps t.
s.
7 n
@'l j@
'O
.ts*
m@,
l 17 O
e
,j 1
2 H
g O'
O e
to 1
e 1
e Figure 3.1 HIN2 TRAP 2 Noding and I
I FkowPathScheme i
1151 089 40 -
t
~
I J
J LIC'JiD LEVEL. V !303 li'l1SIEf!I ll!'E ri!LSSC::12;R !.:.3 Si!!,:' C5::Ent.1Ei:
2 ST;;,",LI::E E.7. l.i' (CDU::D!LG LEl!.lTi (102 Fi, Ei:D 0F LITE,0.0 FT F l:E U. ). ( RC l>ll/ ' 'i H I P )
1 S.C. 1UDE RECID!!
o o e o fj o O
"O FULL F
o m
e t,
PRZR. FULL
[
49 g
g D
C O
O E
e U
g o
D e
o S
D a
y, 30 g
g 6
o g
0 ge e
E D
5 e o U
b
$. 20 "-
D D
O r
D e
e o
6 KEY y
e D:
PRESSURIZER 10 b@
STEl,L' gel:Elt!, TOR ' A' o:
OQ 6:
STEAtt GENERI, TOR 'B' I
-f l
I t
t t
Y 0
2 4
6 8
10 12 14 16 Transient Time (1,linutes)'
Ficure 3.2 a
c 115l 090 u-
e e
e L
,.'e e
m LO LM ti' ce ce o o
>= >-
= n #.
Ee
\\
ts>
LJ
.J
\\
w :: ::
W --
.s
- w w I
R N,
~l 1 o
\\
- o G :s To :: :c ce <>
i.e cc tu eu tu En o.C
.xT.
O' N
V eg
\\
sc *- >-
\\
n.
g
"- M M gg
\\
l\\g g
\\
m.:
^
e w s
b b
~ U uJ K l
ks p
- t S
g ga
- 2 J 40 g
s x
-c w z s
s g
s n.
s s
\\
e s
w _,
w s
s u.1
.s
\\
s s
e.a s
'b.
9 o
r o ia
't3's
\\.
= m c.
N E, m E
=
ss o
s c.
s s
c u.
o s
N
\\
m g
s
's g
ce o
o o a:
s cc s N
E gg h)N - W t" --.-Tq\\
3
^
n
(
o o v.
w w o o,-
m.s.-
o.
_s 2 z
u-
\\
-- o w
\\\\
o
\\
o s us o'
s~mo
\\s A
s u-o s
s
= o o m
b a
w
~ o s
N s
N w = -
N s'ta%
O e5^
E=a s
i s
o w s't b
b e w m w o u.
~
.w cc a.
o k out m
c:
OG O
m a w w ~ o cc o o o.
-s G
0 m
G G
O O
G O
CD o
i t
-- p_ _
i-o o
e o
o En es m
()j) Inol pint:!1 Jo'r: uti) rii'ais Jazi.iiiss3Jd Figure 3.3 1151 091 u-
5 OO G
e n
t
^
a OD c
o-co l
a.
o w cr l
OD G
o
..: ~
~'
i OD c
m
~
- cc w -
N
.g I
OO O
w m a m
cc o.
u-s'-
e m w
I OO G
o v
o e
s
- o. O C
e w.,_
ca.
m
.e-
,z w
u I
D:
OO G
^
.R.-
o a
a-n
.J Q
n e--
w a
6-ce
_a u
I oO c
o o o a e
cc m m u o m m o E
w
.~
m w o g
oO 4
55*
I o o-o 5
>s m
OD C l
Oc c
W I
e m
o u
~
w m o I
Oo c.
x E
= - o
= m c I
Oe c
Os I
c m - m OO c
w w r.:
g c.
o I
OO C
i?
- o E
l Oo o
e--
.- a i
Os c
z m g
Oo G
- tgR I
Do o
8 "'
1 l
00 G
v i
a 4
I g
4 I
CD C
g
~
i e
4 t
T G I
CC 4
/
CO G
/
e s
a d
n b
h.
k (3,,) aJn3clartcol atteloo3 ficuit 3.4 iJl U/2
_ 43 -
?00R ORGINAL C'":LI':T II':?i!.~.i'. '.. i *i T I:5 !'3 1..! '
- ii '.i 1 ' :'.'
~
2 (1 ti2 IF, FF t: llc l' '. (:F l I f i, 12 7 f1 0 0 '! f E':r,, p,.Jit?'E,. S TT * ", i':: P':I.'..
('J'"' I T I C '.T L 9 :
gig fir
- fi" ' O } F5 t D )
]
700,
I Pi:E SSL'R IZEI' E*.:PT IES
' 't F'.1101 LE G P.[ Git:S TV'0-PP.f.SE
\\
)CDUF1000T*.!,5
- ON l
\\
SDD i
\\
's FLDiiS DEGil:S g
\\
l
\\
9 fl0T LEG SilDCOCLED g
h O
\\
l k\\
\\
E ~ 503 -
k\\s e
e' t
2s E
Iss a
ON
"'N
/'~\\
400
\\
'ss,,/
8
\\
\\
n
\\
Q
\\
o KEY B
\\
Q
\\
D
\\
0:
110T LEG (PRZP. LOOP) ng s
p$
300 e:
CORE a: COLD LEG (PRZR LOOP)
.--: SATURATIO!! LINE O
9 2oo D
2 4
6 8,
10 12 Transient Time (.fiinutes)I Figure 3.5 1151 093
k CGnt. A! 1 TE**iiiil.TU'.ES VEP305 1 :l. :S!E! 1 11:%
(107 ' FP, BEUlt"!,Il<G 0F LIFE,12.2 fi MU'di E;;3 n"i'iU::E,U::':1110!.TED SlEl."t.II:E DEE!.Y.,P.C I U U.P li:lP )
3g9 PRESSURIZEP El4 piles fHDTLEG BEGII:S T7iD-PHASE tt CLEE FLOC 0 TAIK 000
's' N FLD7! EECI::S sN I
0bb k
i HDT LEG SUCCDDLED g
s 1
o o
sq i
s o
o y
g 500 o
o A
s e
'Ds h
o D
bs o
o D
'o o
g E
b s%s T;
o o
b%/
0 400 o
o o
o g
0 o
D
.c U
o e
D KEY 3
o:
HOT LEG (PRZR LOOP) o 300 G:
CORE o
a:
COLD LES (PRZR t00P)
SATURATlDil LINE i
1 200 0
2 4
6 B
10 Transient Time (idintite:;)
Figiere 3.S
. 45 -
TOTAL STEAM BUBBLE VOLUME VERSUS TRANSIENT 'Till.E 2
(102% FP, 12.2 FT UNMITIGATED DOUBLE-ENDE0 STEAMLINE BREAK) 300 lO.4 o
's l
9 200
,P O
v b
t.
n 2
,0 l
O 3
d b'
KEY m
/
g
.i
,0 e: HOT LEG LOOP 'A'
/
,U ' 's (PRZR)-RC PUMP TRIP 100
/
O: HDT LEG LOOP 'B' -
o s
j g
j (RC PUMP TRIP) a: HOT LEG LOOP 'A' O' /Fg b
,s' ! /4,. \\
\\
(PRZR)-ND PUMP TRIP
~
n o
/
/
\\
N o
G: HOT LEG LOOP 'B' -
9 i
(N0 PUMP TRIP) i+b 0,
dN e
0 2
4 6
B Transient Time (minutes)
Figure 3.7 t
e b
1151 095 9
e
\\
ra Cf "E Di'!!! T Pii " "" Hi'5 US 13:* "'; 18. ill i I"!
2,;;",tg t
(1D2: IP EE01::':!:0 Of LITE.12.2 Il EliD liUr it ;ti,b:J:111LAlED 51L A.L I.E C ;Lt.K) 250C,
t'.
2000 -
O._'
mt 6
5 1500 -
h 6
e E
o KEY O:
RC PUMPS TRIP
~
S o
a:
NO PUMPS TRIP S
1000 0
6 O O
6 O
o O
500 0
0 6
O cP 6
oo ooO e
OfQO O
b a n a t
0 t
0 2
4 6
S 10 12 Transient Time (1:linutes) figure 3.8 t
115l 096
,w
,a e
x 3
e--c><
I
. r.
.....--.--..?...-'--.........;e------'0-------------
e i
g M
m ov 33 sc 4'
f 7
ErioV-N-I
'e G
r,wh 15
.21 f.y y
r.
g' 1
Ol 5
D
]
su r
~O O
~
i O J g.,
-p I
.g e
4 gb J
3 J
G L
It
?7 IL
/6 A4 3
^
CFT e
r Os (O Q O
@{
O a
15 2s 7
12 Gj b
l@
Q 2 S'
+
17 0
2 E
{-
E l 14
~.
lQ 9
Te>
l J'
G g
' Figure 3.3 0 t
I HIN'ITRAP2 Noding and Flow Path Scheme q
-48a-
.-p e
g
g-
- Y
}
rj
/
l.*
- mio... '
C.~7* X/(TYl')
/
TYh Fto;v tA~TCR NOT ZLT CufW:;a
/
3ECT ION V V' 3
kg
? W ' * ' b'*
f ray,t;, st O L
~IO 1
l2(g re.rs siet.
x,
~5' f
LCV. >'- 2 G__
\\f y
5.
j
~
l 0
T
}/nwww d ".*Q) g--
Q 3 x;n="
g 0
ip c e
[E
- l y
r 9_?l? P " ~ ~ i, Z. !v a esc 4 y>
jy3 t_. -
I
,g.
5
~i to U
.b..
5 l
5 i
.- % ; m e
m..C k
i sARY FE EDW ATER l
y,
^- g NLET NO7.7_t E t m mletRMA.WLte g
5 c
,v
{
'U tt41 ATION EF LMG tao.I S.
k E
,u 0
Y
'L, E L E V. G 4 E'- O$.
(4
' /l
_ y
(
^'
< KEF V %./
i f*- $
\\
~
0-(
/
gg g
n I
1 A
j t.
) CEcv Gas-wE,I z.
.gi___\\
j ggeyc.
i y
T}-d__..).u'itE__R l_. - _.
are
/
"m=aur t
I
/
Puur
~
xM ELEV.GE.0 -O '
/1
,pp i ctEv. oso'.c.-
'P3OI G
l
'1L-U
\\*
~
8 REF h
w f
T p,
g
\\.
f (
.8 f O FEEDWATEN
\\
\\
-- E "-
)
e L,K_;Jj
%d g&,.
jttEF,to'oroR
}s L.,
(
jrATs0N SEE NEF Nmelsweg I
g j <f y --
(
Q
\\.
Hot Leg Noding
~ " Figure 3.11 1131 098 C
-48b-
\\ m-u..
TOTAL STEAM BUBF,LE VOLUME VS TRANSIENT TIME 2
(102% FP, 12.2 F1 DOUBLE-ENDED UNMITIGATED STEAMLINE BREAK, RC PUMP TRIP) s 2
MAXINUM=3G6 FT e300SECONOS 360
- o%
a a
o 300 3
E o
240 3
E 2
E E
180 1
a a
8
'a G
5 E
120 T
t/3 O
60 KEY 3
a: HOT LEG /S.G.
UPPER HEAD.
cn (LOOP 'A'-PRZR
^'
^'
0 2
4 6
8 10 12 14 a-a Transient Time (tnirtutes)
-c
I e
s T
~
j I
w N
E W D W
g W W g
Z 4
.:g w LD W
m M &
O Z O
Z
~
o -
e 4 E O CD M Z J W y_
W D w g3
^
M C ^
m D W A uJ !B:
6.1 g Q w
M O
~
O J 3
E Z M O W C
w w W m -
W D-E E: J E v
Q.sD D
e g3 J W Q-CD
.E A O w
O O J
W f.4 W
ZN w y ext &
O U L Z g
M at as
>= N W Z
D!
M c
Z N M g
cs asC "
C/) E I
w U
W W W l
W
-Z Q
T 0.
==
3 m
=EC W
-8 CL Z
= ' 49 4 E C/)
w w Q.
N W J
o o i-e m o - m m m J V N D N
- w m
= E V3
=cC V) W m W m w D.
V
=_~
=
g a
8 8
o o
o o
o g
8 8
8 8
=.
=
=
a a
a e
N (cas/wat) sol.1 aue3 Kpuc3,y, dool Elgure 3.13 1131 100 r4
..g.
A pe ieN'
- 9
=
b
Loop 'B' CANDY CANE FLOW VERSUS TRANSIENT TIME 2
(102f, FP, 12.2 FT 000BLE-ENDED UNMITIGATED STEAMLINE BREAK, RC PUCP TRIP) 16,000 14,000 n
o k
12,000
<!?
5 10,000 t
1 w
5.,
"8
=
0,000 Y
E r
o p
6,000 o.g a
4,000 2,000 u,
r 0.000 a
0 2
4 6
8 10 12 14 Transient Time (minutes)
Y
)
~
m o o x w e o
-.- z o
w w
^
z w w
.==
w a m
- o e M D
=
= o w-c 4 o z o.
- e a w
.- m.-
x v
z.-
g v,
u.
D L&J Q.
m n.- =
m
- 00 D w m o.
- - o w
c o =
=
o n.
a w =
mc u.
o.-
=
w ~ _
m o x
+-
o - z a.
v D m
e e
i e
is o
o, e,
c, c,
o o
o e
o e
c3 o
c, o
o e
o o
o o
e.
o.
o.
o.
o, o,
o c,.
c,"
,c>
o o
o o
o c>
e c>
m
=
~
o o
Das/qi 'mol3 ajaa F1 ure 3 i...
!151 102 f
o e
g e
e
~
^
n.
n.
o o
o o
w m z
=
w -
~
m
- a..
cc a.
.z a.
m v
o o
a w. -r w
a 23
. C2, uJ
. m C2 o o af z a o w
>. O O
<3 I.
w
[
I V
Mn
\\
o o
m g
z r
w 1
o D d-
-o w
o z
c>
1 w
o m
1 o
o w
=>
o o c
~
m o
o w
ci m w s
m o
m >-
u
- a w
w 3
/
o O
G
.- a V
N J, y
s-s.
.z.t c:
=> u.
c>
I z -
w m ww z
i C'
S, "w "
/
o O
G z
pO n
c cc -
m c.
m cc w n.
J o.
/
e u.
o o
o
.- o
=>
z e
/
C 0-uJ u.J m
t/>
= ii
/
=>
o e
C t/>
uJ n.
o v
5 E! E
/
=>
=3 c.
e o
i w cm o o
e o
w cc w
e-m g
ce m e
u.
x z
I
=> +-
=c n
o e
c
=>
r
-x m
a w w I
w
. ce ci m mc
- o. m o
=
~
s-s m -
c.
o g
q c3 w
w 2
m m I
s-x w a.
I s-u.
-m a cc e
o z.t, o w w l
m m m ~
I c>
c>
c>
- m a ec I
d 5 o a 4
I mE~
/
m o
/o e o
z =
/
/
c Q
p
/
w
't I
I I
o
_2
~
o o
o o
e, c
c2 o
o o
c,
.e c3 n
o w
o u
(3.) 'sajnlejadmai luetoo3
/ Figure 3.16 1151 103
'~ ~
M b
f
=
4
' e M
O O
H 9=
af af M
E Cc w w w
N Z
Z w*
w CC C
W D
^
C4 E m E Co asC N aC W
W CC w
CE 9-A p.=
A*
 v t/3 e
E O O G
W W
u m
g Q
-e-o D
<9 9-5J g
Od
-a
" w D
O 4
N e
Z CE M*
OO 4
- E O
Dd m
=>
s O
OC w m CE at Q
g O
e w w l
^
2=
D--
O.
in M
su J
O
+'
w cs
=>
> w w a o
c a z E
W ^
O Co V
O e
A O
su
- w
=
- J Cr E3 o m e--
0 m
e-s o n.
O y
a e
a o n.
O co su e-w O
m er 9-Cx: er e
w w m
z -
o w
t-o m
m z d T est =>
w
$=
N
 t-a W
QZ N aC
=
N N
CE===
Q[]
w N.-
=
o.
CC 6 D
=>
to kt O
m N w a 0
I r."
f f
A O
CC -
~
A v o
o o
o,e c,>
o C
N e
(1D laAa1 Jolejauss meals /JazijnssaJd Figure 3.17 1151 104 e
e 9
q w
d em
,e.N.
e e
s W
e o
N n.aJ w
e E
t-
===. auf D-C.3 6-6-
z s.aJ E
Z o
to D e
Zact a ^
a Cr taJ Ch.
^
b==
C3 -
M Z
Fr.
as to 6.aJ 0-se p
e
- '3 to 44J C.
C cc J ::i2 CD
~
taJ c3 D E
.lp=
D A v
c3 w a C3.
as En CE E
DN to 6-9-
to A M w
at M
CC N LAJ CD C.,
CC C
m ea e
w w
C Z
a
=
n.
m.A a o
=
kt at
,e w ~ w Ex'
= W o - En u v
_ m e
t i
i c.,
es cm cm o
o o
c o
c3 c2 c2 c2
=
=
o, c.3 c
o e
o e
o e
o c3
=.
m m
n
~
o
~
(Isd) aJnssaJd tallnD ajaa Figure 3.18
? ] c, l rnq e
. _.. _ ~ _ _.......