ML20064N300
| ML20064N300 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 02/28/1994 |
| From: | Calvo R, Mueller N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML19304B884 | List: |
| References | |
| WCAP-13962, WCAP-13962-R02, WCAP-13962-R2, NUDOCS 9403290248 | |
| Download: ML20064N300 (86) | |
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.WCAP-13962 SETPOINT PROGRAM DETERMINATION FOR THE WESTINGHOUSE COLD OVERPRESSURE MIT1 GATING SYSTEM IN THE HOUSTON LIGHTING & POWER SOUTH TEXAS UNITS 1 & 2 (Rev. 2)
R. Calvo. Adv. Technical Engineer Control Systems Analysis Rev.1, Feb.1994 Approved by:
N. P. Mueller, Manager Control Systems Analysis WESTINGHOUSE ELECTRIC CORPORATION Energy Systems Business Unit -
P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355
@l994 Westinghouse Electric Corporation All Rights' Reserved l
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l li TAllLE OF CONTENTS
- 1. DISCIISSION/flASES . . . .. .. ... ... . .... . . .... 5
- 11. SPECIFICATION FOR M ASS INPilT TR ANSIENTS . .. . . . . . .. 8 A. Temperatures . .., . . . . .. .. ... .. . ....... 8 Reactor Coolant Systern Volume B. . .. .... .. .. .. ...... h, C. Reactor Coolant System Relief Capability . . . .. ... .. . .. .. 8 D. Power Operated Relief Valve Characteristics , . . . . ..... . .......... 8-E Mass Injection Flow Capability .. .. ,, . ... ....... . 9 F. Pressure Sienal Transmission Characteristics . .. . .. ... .. 9' G. Results Required .. . , .... ... ...,.. . ... . . 9 111. SPECIFICATION FOR llEAT INPIIT TRANSlENTS . .. . . . . . . 13 A. Temperatures . ... .... .. .. . .. . . . .... 13 B. Reactor Coolant System Volume , . . . ..... ..... .... 13' C. Reactor Coolant System Relief Capability . . . . . ... . .. . .... 13 D. Power Opemted Relief Valve Characteristics . . . . ... .. .. .. 13 E. Steam Generator Design Characteristics . . . . . . ... ..... . .... 14 F. Reactor Coolant Pump Design Characteristics . .. .... . .... .... 14 G. Pressure Sienal Transmission Characteristics . . .. . . . . ..... 14 -
- 11. Results Required . . . ..... .. . . . ..... . . . ...... 14 tgxt: tens.wp/070793 3
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IV. SPECIFICATION FOR DETERMINATION OF SETPOINT PROGRAM ... 17 4
A. SETPOINT PROGRAM ALGORITHM ..... ...... ............. 17 B. . TR ANSIENTS CONSIDERED . . . . . . . .... .. .. . ... . .. .., 17 C. 10CFR50 APPENDlX 0 PRESSURE LIMIT . . . . . . .. .. .. . . 17 D. REACTOR COOLANT PUMP NO. I SEAL PRESSIIRE LIMIT ... ... 18 3
T E. PRESSURE MEASUREMENT DIFFERENCES ... .. .. ........ 18 '~
F. OTilER CONSTRAINTS .. . ... ... . .. ... . . 19
- V. RESULTS OF PAR AMETRIC REACTOR COOLANT SYSTEM (CONSTANT) MASS
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. INPUT TR ANSIENT ANALYSES . . . ... . ... . .. ... .. .. 22 f
VI. RESULTS OF REACTOR COOLANT SYSTEM llEAT INPIIT TR ANSIENT AN Al.YSES , . .. .. . .... ..... ............... ......... 33 Vll. SETPOINT DETERMINATION . . ......... ....... . ....... . 40.
A. BASES . . ... . . ... ..... .. .................. 40 b
e B. LEGEND APPLICABLE TO GR APHICAL ALGORITilMS . . . . . . .. .. 40 C. DATA UTILIZED . . .... . . . . .., . .. ... . 41 j D. Al.GORITilM APPLICATION . .. .. ....... . . .. .. 43' 1 Vill. SETPOINT PROGR AM . . . . . . . . . . . ..... . .. ... ... ........ 61' APPEN DlX A . . . . . . . . . . . . ......... . ........ .. .. ... .... A-D l
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' l. DISCilSS10N/B ASES -
This report documents die development of the power-operated relief valve (PORV) setpoint programs (pressure setpoint vs. reactor coolant system temperature) as detemiined for the Westinghouse Cold Overpressure Mitigating System (COMS), to be applied during startup and shutdown operations in the South Texas Units 1 & 2. These programs are intended to maintain the reactor coolant system pressure within acceptable limits following overpressurization incidents occurring during low temperature, water-solid operation. The results of the LOFTRAN transient analyses, utilized in die detennination of the setpoint prognun, are also included.
This report is a revision to that developed in Refemnce 2 to account for the pressure difference from the wide-range pressure transmitters to the location of the maximum pressure limit.
Occratin_c Limits The PORV setpoint pmgnun was developed for this plant, utilizing the algoritlun provided in WCAP 10529 (Reference 1). Relict valve operation based on die setpoint program will prevent overpressures produced by valve opening from exceeding the limit which is based on the more lhiting of the 10CFR50 Appendix G reactor vessel NDT limit or the maximum RCS pressure requirement as dictated ,
by PORV piping reaction force considentions and will prevent underpressures produced by valve closure from violating the reactor coolant pump No. I Seal minimum pressure requirement. This was accomplished by considering both the Mass Input (MI) and Heat input (111) mechanisms and by utilizing staggered relief valve operation.
Ileatup and cooldown cu ves for isothermal conditions and without instrument ermrs, applicable to 32 EFPY, were utilized for the Appendix G limit (see Appendix A of this document for details on the .i Appendix G limit calculation). A notch was incorporated at 120 F and 621 psig to accommodate the d vessel flange limit. The maximum allowable pressurizer pressure based on PORV piping force considerations is 800 psig.
1 i
'J The minimum RCS pressure curve utilized in the setpoint detennination is based on the system ;
pressure as detennined by a wide range pressure instrument in a loop not containing the active reactor coolant pump. This ensures the utilization of a minimum pressure limit curve which will cover this eventuality as well as that case in which the instrument is directly located in the loop with the active l
- pump.
Due to the difference in location of the pressure transmitters used for RCS presssure measurement vmmwprio7e -5 -I l
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~ (located in RilR piping connection off of hot leg) and the pressure at the location of the maximum -1 pressure limit (reactor vessel downcomer for Appendix G; top of pressurizer for PORV piping force),
the appropriate pressure difference must be accounted for. This is done by subtracting off the pressure dilference from the maximum pressure limit.
When the Appendix G limit is applicable, the pressure difference was based upon a maximum of either two or four reactor coolant pumps operating. When the PORV piping force limit is applicable, no additional pressure difference is accounted for since for all transients of concem the pressure at the ,
pressure transmitter is greater than the pressure at the top of the pressurizer.
The minimum RCS pressure curve is based upon a reactor coolant pump No. I Seal AP equal to 2(K) ,
psid.
s Mass Input Considerations From the standpoint of detennining maximum setpoint overpressure and proximity to Appendix G, the mass input (MI) mechanisms considered in the analysis involves the following operations:
- 1. RCS Temperature < 2(KFF One centrifugal charging pump with inadvertent isolation of letdown flow and charging control valve fully open.
- 2. RCS Temperature 22(XFF Combined maximum deliverable flow from one high head safety injection pump and one centrifugal charging pmnp with letdown isolation and charging control valve fully open.
t From the standpoint of detennining maximum setpoint underpressure and proximity to the RCP' number 1 Seal minimum pressure limit, an envelope of mass injection rates was investigated to ensure ' !
that the worst case was considered for ultimate setpoint detennination. For both the underpressure and ,
overpressure transients, mass injection rates nmging from 50 gpm to 1600 ppm were considered,
'i Heat input Considerations The heat input (III) mechanism considered for analysis involved the inadvertent startup of a reactor ,
coolant pump in one loop. Temperature asymmetries in the reactor coolan! system, whereby the steam inumwntrarm 6 i
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generators were at a higher temperature than the remainder of the system, were assumed in the analysis. The magnitude of the temperature difference between the steam generators and the reactor ,
coolant system depends on the previous phuit operations which allowed the asymmetry to develop. )
For this study, it was considered realistic to assume a maximum temperature difference of 50 F as the design case because much higher differences would be difficult to develop and would be easily recogni/cd by the operator as an abnomial condition requiring special attention.
PORV Operation Staggered operation of the two power-operated relief valves was selected to ' minimize the potential for .
larger pressure undershoots, which could result from multiple valve operation, from compromising the reactor coolant pump No.1 Seal integrity. It is also desirable to restrict the total number of ports for the discharge of primary coolant at any given moment to that absolutely necessary for pressure control.
The dual setpoints required for staggered operation were detemiined such that the multiple valve ;
operation is minimized. In addition, the operation of either PORV provides the relief capacity required ,
by the design basis. This redundancy is an essential factor in allowing the COMS to comply with the single failure criteria design objective. For South Texas 1 and 2, for RCS temperature 2200 F, the power operated relief valves are staggered, to the extent practicable, to minimize multiple valve operation for the required relief capacity from one high head safety injection pump plus 100 gpm net charging flow. The required relief capacity for the design basis will result in multiple valve operation if both COMS trains are operable, However, our analysis indicates that the operation of one PORV provides the relief capacity required by the design basis without exceeding either the 10CFR50 Appendix G reactor vessel NDT limit or the maximum allowable PORV piping force requirement if ;
failure does occur to preclude operation of the other valve. Our analysis also indicates that the undershoot resulting from multiple valve operation will not violate the reactor coolant pump No. I seal minimum pressure requirement.
Manufacturer's data was used for the development of the Garrett PORV opening and closing .
l characteristics. Delay times for the PORV solenoid actuation (from receipt of signal to start of valve motion) were based on data measured at various sites employing the Garrett relief valve.
The setpoint program utilizes 0.3 see for the effect of time delays associated with transmission of the ' .
wide range RCS pressure signal. In addition to this 0.1 seconds was used as the PORV solenoid l actuation delay time (time from receipt of signal at solenoid to stan of valve motion).
Should the time delays or valve characteristics mentioned above prove to be more adverse (i.e., longer delay times or longer PORV stroke times) upon installation and testing, the setpoint program in m m.wn u70793 - 7 i
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l developed in this report would have to be re-evaluated; sensitivity runs to quantify the correlation l between longer delay times and/or valve stroke characteristics are not available for the South Texas specific configuration or design bases.
II. SPECIFICATION FOR MASS INPUT TRANSIENTS Transients Analyzed A panunetric study (Section V) was performed using constant mass injection rates between 50 gpm and 1600 gpm with the RCS in a water solid condition. For the range of setpoints considered, this mass input range was sufficiently extensive to envelope the RCS mass injection rates associated with the maximum possible from one centrifugal charging pump following leidown isolation while RCS temperature is less than 200 F or from one high head Si pump and one centrifugal charging pump with letdown isolation while RCS temperature is greater than or equal to 200 F.
System /Operatinn Panuncters A. Temperatures Reactor Coolant System temperature is equal to 100 F.
B. Reactor Coolant System Volume The RCS Volume is [ f' cu. ft. for South Texas 1 & 2.
. C. Reactor Coolant System Relief Capability The transient is either analyzed for actuation of one power operated relief valve to detennine the most limiting overshoot or actuation of two power operated relief valves to detennine the most Ihniting undershoot.
D. Power Operated Relief Valve Characteristics
- 1. Opening / closing characteristics - see Figures 3.1 and 3.2.
- 2. Opening time = 1.65 seconds (plus 0.4 second channel delay) tpmus.wp'070793 8
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- 3. Closing time = 1.(X) seconds (plus 0.4 second channel delay) - '
- 4. C,= 60 E. Mass Iniection Flow Capability
- 1. Nonnal flow into the RCS: 100 ppm
- 2. Infrequent operation:
For RCS temperature < 200*F, refer to Figure 2.1 for the maximum credible flow rate that can be delivered at a given RCS pressure by one centrifugal charging pump. For RCS temperature.>_2(XPF, refer to Figure 2.3 for the maximum credible flow rate that can be delivered at a given RCS pressure by c ne high head SI pump and one centrifugal charging pump with letdown isolation.
F. Pressure Si_enal Transmission Characteristics Time delay to PORV actuation = 0.4 see G. Results Required Table summarizing the setpoint pressure overshoot, setpoint pressure undershoot,inaximum RCS pressure and minimum RCS pressure reached for all transients during either one PORV operation or two PORV operation.
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INJECTED FLOW VS. RCS PRESSURE ONE CENTR. CH-ARGING PUMP
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Figure 2.1 tpctus.wp/070793 10
l INJECTED FLOW VS. RCS PRESSURE ONE SAFETY INJECTION PUMP l b, e 6
D5 k
w T
~D w
w w
E O_
m O
C
_ rLOW (GPM)
Figure 2.2 ina.nsaiomn9 t i1
d I
l l
INJECTED FLOW VS. RCS PRESSURE CHARGING PLUS SI PUMP b,c l'
l t
i.
Of E!
E w
[
D CD CD W
E O.
CD O
E l
1 '-
7 FLOW (GPM)
-i i
I l
Figure 2.3 tpeuna wptI70791 12 1
l Ill. SPECIFICATION FOR llEAT INPUT TR ANSIENTS .l4 1
Transient Analy7ed Inadvertent startup of a RCS pump with temperature asynunctry between the RCS and SG and with 1 the RCS in a water solid condition (lleat input mechanism producing the worst case l overpressurization). l
.i I
System /Operatine Parameters
')
- ).
A. Temperatures SG - RCS temperature difference = 50 F
'I Steam generator (heat source) temperatures are 120 F,150 F,175 F,200 F,220 F. 250 F, 300 F. 350 F; corresponding RCS temperatures are 50 F lower.
I IL Reactor Coolant System Volume :j 6
The RCS volume is [ 1 # cu. ft. for South Texas 1 & 2.
C. Reactor Coolant System Relief Capability The transient is analyzed for either the actuation of one power operated relief valve to detennine the most limiting overshoot or the actuation of two power operated relief valves to detennine the most limiting undershoot.
D. Power Operated Relief Valve Characteristics Openinc l
- 1. Opening characteristic, see Figure 3.1
- 2. Opening time = 1.65 seconds (plus 0.4 second channel delay)
- 3. C, = 60 Closure tgmsm.wp/070791 13
e'
- l. Closing characteristic, see Figure 3.2 i
- 2. Closing time = 1.00 seconds (plus 0.4 second channel delay)
- 3. C, = 60 E. Steam Generator Desien Characteristics SG Tube Heat Transfer Surface Area is [ ]6# ft2 per steam generator.
SG Type - Model E2 F. Reactor Coolant Pump Desien Characteristics RCP Type = Model 100A RCP Motor llP = 8000 G. Pressure Sicnal Transmission Characteristics Time delay to PORV actuation = 0.4 sec ,
- 11. Results Required Table summarizing the setpoint pressure overshoot, setpoint pressure undershoot, maximum ,
RCS pressure and minimum RCS pressure reached for all transients during either one PORV operation or two PORV operation.
t f
(
tpetuns.up'070793 ]4
GARRETT PORV OPENING CHARACTERISTIC 1 , _ , .
> 0.9 :
F- .
0 '-
< 0'8 : :
Q.
< 0.7 --- - ' - - -
O ' '
$J 0.6 . .
-1 l
> 0.5 i
0 ' '
0.4 ---- - - - --
, r- -- -- - - - - -- - - --
N .
J 0.3 2 . . .
m 0.2 - .
O - . . . .
z 0.1 - - ---
-4 O
I I i l I F
l J 1 I I I I I I i ! I 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 TIME (SECONDS)
Figure 3.1 inmm.wpammo ' 15
l l
1 i
GARRE I I PORV CLOSING CHARACTERISTIC l l
1 ~
> 0.9 - ' - '
F- .
04 0.8 .-
l n_ . .
l
<0 .7 -- - - - -
o ' '
I uJ '
> 0.6
.1 .
> 0.5 .' . .
00.4--- -
-j -
N . . . . .
]4 0.3 2 . : . . :
a- 0.2 - , -
O - -
Z 0.1 --- - - -
O f l- i l +- l f l k i 0 0.2 0.4 0.6 0.8 1 TIME (SECONDS) 1 I
l i
Figure 3.2 l 1
agxcantwnwin9.1 16 i
.. . . . . . . . ... . . = . . . . . _ . _ . . _ = _ . . . . . _ . . _
IV, SPECIFICATION FOR DETERMINATION OF SETPOINT PROGR AM A. SETPOINT PROGR AM ALGORITIIM Procedure described in WCAP 10529.
B. TR ANSIENTS CONSIDERED
- l. Mass input All cases described in the specification for mass input transients (Section 11)
- 2. 11 cat input All cases described in the specification for heat input transients (Section 111).
C. 10CFR50 APPENDIX G PRESSURE LIMIT South Texas Units 1 & 2 Limits Considered The 32 EFPY isothermal curve without instnunent errors as shown in Figure 4.1. These values are calculated specifically for Unit I and also bound Unit 2 (see Appendix A).
Curve Utilized -
The 32 EFPY isothennal curve described in Figure 4.1 (Most limiting for applicability. rates given .
below).
Applicability South Texas Units 1 & 2 for isothennal conditions. Isothennal curves are considered to be appropriate for use in the development of the setpoints since the majority of the pressure transients occur during isothennal metal conditions. This is the standard Westinghouse position and has been included in analyses done on other plants.
.igactms,wp/070793 ~ 17 ,
H
- 1 D. REACI'OR COOL. ANT PilMP NO.1 SEAL, PRESSilRE LIMIT ,
l 1
- 2. Applicabilh
- a. RCP No. I Seal AP = 200 psid E. PRESSURE MEASUREMENT DIFFERENCES The COMS logie uses the wide range pressure signal to actuate the PORVs. This signal is measured in the RilR suction line connection to the RCS hot leg. The maximum pressure limit is the lower of the following:
a) Appendix G limit, evaluated either at the reactor vessel downcomer at the elevation equivalent to the core midphme or at the reactor vessel bolted flange b) PORV piping limit, defined as a pressurizer pressure at the PORV hilet of no greater than 800 psig For when the Appendix G limit is controlling, the pressure difference between the pressure at the vessel and the pressure at the location of the pressure transmitters will be subtracted from the Appendix G limit to arrive at the limiting pressure at the transmitter location. The value is based upon either a maximum of Iwo reactor coolant pumps operating or a maximum of all four reactor coolant pumps operating.
Vessel Flange Downcomer - ,
a) Four RCP operating: [ ' f# psid [ f# psid b) Two RCP operating:
Pressure transmitter in active loop [ f# psid' ![ f# psid Pressure transmitter in inactive loop l lb" psid l }6' psid 2
-. i l
trnunsa ntr/0793 18
- - _ - . .= .
l:
! .: )
. c 1 l
For when the PORV discharge piping limit is controlling, no additional pressure dif ference need be l considered. This is due to the wide-range pressure transmitters always measuring a pressure which is no greater than the pressure existing at the inlet to the pressurizer PORVs.
F. OTHER CONSTRAINTS f
- 1. Staccered PORV Settmints
- a. Either PORV provides the required relief capacity (single failure of either valve is considered).
- b. Ifigher setpoint of second PORV reduces the likelihood of its operation if first PORV (at lower setpoint) operates.
- 2. Plant Operability The highest possible setpoints were detennined, consistent with the limits and constraints described in this section (Section IV), to provide the plant operator with nutximum pressure margin for plant operation during startup and shutdown.
- 3. Thennal Transport For a heat input transient as described in Section III, it is possible for the temperature RTD to measure a higher temperature than that of the vessel. To account for this ;
cffect, it was conservatively assumed that the RTD was measuring 'a temperature 77 F higher than the vessel temperature (50*F difference between primary and secondary plus 27 F for instrument accuracy).
4 I I I
l l
]
1 tpmus.wpV70793 19 l
l TGX COOLDOWN CURVES R.G.1.99, REV2 32 EFPY W/O MARGINS 2500 ++> ++
_4 4 4>.
++
.t 4 .p.. +1 .. _ . _ _
4-r-T+1 i i ! i i
_{.__. _r i
y f. .1.. q,
+ )'
I i
...L _ . _ . . , . . _... . _ _ ...
2250 -r{.+ t +T T l- ..._4_.. -+ r_+ --. __ r-.
t q_ 4u_..p__t m4 . _ _
p3fp _f. + 4 _4 _+44 _ _
.y
! _ _ L . 11 L ! ! !
2000 UNACCEPTABLE -
4- 4 f - - -
44 - - - - - --
f-- - - - -
O .l_ OPERATION i
! d ! !
- q. gg p' _f .p'+
g 4 ,
. y 44 A a-1750 g!
a._ _ a_
.r! 2. _'_a ___ _
q W -
t a_ !
x x .s..'
- g. _ _ ..
.a.. . .-_ . - __
.r.- -.-
>1500 !
2/ _)i . j i co co i
47 i .
+ _
- 1 4pp..p..___ -
_+ _.y + i M
^
w 1250 .+7 g
, ---- 1 - ---- - I - -
j 4- 7. . _ -_-
K" . _ .p 4 Q ACCEI'rABLE 1
.,.._ 4A _ _ .._ ._ - , _ ._ _ .. ._
PERAEN a1. 000 w
i
! 3 f
g t-i
<C ..r '- + +! .. -
_+._g_- - .. . _ .t _L4
_0 750 -+4+ ;
1 ! ---
-y. + ..y 4
.. 1
+__
._+4_
a .
r.---
-- f_._-+
7 '
, . .+~
500 M'COOLbOWN RATEY "I
~~ ~~~ ~ ~~ ~ ~
~P [T ~
[0 DEG F/HR _ _ _ __. __
4 ., ._ _
41 Z 250 " _..i . -
q i
q' ..-4q' 4.
_L._. _ . _p... _ - ___ . __. .. ._._ . ._ .p!. . .
I ! i i i ! ?
e i f
. . ~ ..
j.. ...d... . . .. {_.._ , . _ ..
_..]_, _. . .. _
.Q..
0 r, .. .
i
,i i
, ; i
.nio 0 50 100 150 200 250 300 350 400 450 500 INDICATED TEMPERATURE (DEG. F) i Figure 4.1 agmans.wntf/0791 20
l l
l MINIMUM RCS PRESSURE FOR PUMP START SOUTH TEXAS UNIT 1 AND 2 300 290 - .
I N t O
-280
, N~~ ~ j 270 T- r- . )
W
[
260 '
D w 250 -
j!
w ;
i $ 240 4- i l Q w 230 j o -
i
[ 220 '
210 i- - -- -
200 + H F---+}+r;+H+ql+9+q +pp gg q.ggg.FeRH+H 0 100 200 300 400 500 RCS TEMPERATURE (DEG F)
Figure 4.2 inn ns.wnv70792 3j l -
. .. . .- - . ~ . . . . - . . .. ... .
l j
. .i l
j
.d l
V RESULTS OF PARAMETRIC REACTOR COOLANT SYSTEM- ,
4
.(CONSTANT) MASS INPUT TRANSIENT ANALYSES SOUTH TEXAS UNITS 1 &~2
'tpcenns w;4r/0793 22
~# * * ' - e--ww.=.- ,,
I TABLE 5.1 SUS 1NIARY OF STASS INPUT RESULTS FOR ONE PORV OPERATION j i
APoua Pyu APaora Pyn Niass Setpoint Peak Selpoint Niinimum input PS Pressure RCS Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot" Pressure 1
)
(com) ( psie ) (psi) ( psic) (psi) (psie)-
6,c -
50 200 300 4 4(X) 500 600 7(X)
M(X) 9(X) llXX) 100 200 3(X) 400 5(X) 6(X) 7(K)
S(X) 9(X) 1000
- Pyu P3
" P3 Pyn apcoms w;AT10793 23
.3
'l TABLE 5.1 (Con't) -1 i
SUMMARY
OF MASS INPUT RESULTS FOR ONE PORV OPERATION t
(
-l Puty APove.n Puxx APesota Mass Setpoint Peak Setpoint Minimum
'- Input PS Pmssure RCS Pressure : RCS i Rate PORV Setpoint Overshoot
- Pressum Undershoot** Pressure
.(gpm ) (psig) (psi) (psin) (psi) (psic)
- .- h,C 200 200 300 i I
400 l J 500 i !
l 600 j 700 ,j 800 900 l 1000 400 200 300
-400 500 ,
4 600 700 800 900 1000 Puix - P3
- P3 - Puy isica m w g vo793 24-
4 TABLE 5.1 (Con't)
SUMMARY
OF MASS INPUT RESULTS FOR ONE PORV OPERATION APova Puxx - _ APcxou Pym Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot*
- Pressure (gpm) (psin) (psi) (psie) (psi) (psie) b, C 600 200 300 400 500 600.
700 800' 900 1000 700 200 300 400 500 600 700-800 900 2 1
10C0
- Pm - P3
- Ps - Pym agacoms.wpAr10793 25
1
)
9 TABLE 5.1 (Con't)
SUMMARY
Of MASS INPUT RESULTS FOR ONE PORV OPERATION
.1 i
APovt.a Pu.sx APaota Pum Mass Setpoint Peak Setpoint Minimum input PS Pressure RCS Pressure 'RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot*
- Pressure (J?pm) (psig) (psi) (psig) (psi) (psie)
~
-1 0
800 200 300 400 5(X)
{
600 l a
7(K) .- l y
800
]
900 l
1000 900 200 <
300 400 500 600 700 800 900 1(XX)
) Py4x - Ps
- P3 - Pun I
isma = wrmam 26
TABLE 5.1 (Con't)
SUMMARY
OF MASS INPUT RESULTS FOR ONE PORY OPERATION APovga Puu APcxoea Puy Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot** Pressure (mm) (psic) (psi) (psic) (psi) (psie) b,C 1000 200 300 1 400 500 600 700 800 900 l 1000 l
1200 200 l 300 400 l 500 600 700 800 ,
900 1000
- Puu - Ps
- Ps - Pus Note: (1) APovta and P , are unlisted because the corresponding mass input rate exceeds the PORV relief capacity at the designated setpoint. Figure 7.1 will be used for the resulting peak RCS pressure for the transient scenarios resulting in these flow rates.
tascans.wamo793 27
TABLE 5.1 (Con't)
SUMMARY
OF MASS INPUT RESULTS FOR ONE PORV OPERATION APovt, Puxx APowot, Pun.
Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot*
- Pressure (mm) (psieL (psi) (psie) (psi) (psie)
_ b, c, 14(X) 200 300 400 5(X) 6(X) 7(X) 800 9&)
1 1000 1600 2(X) 300 400 500 600 700 800 900 1(XX)
Pu u - Ps
~~
igxcorns wpU70793 28
TABLE 5.2
SUMMARY
OF MASS INPUT RESULTS FOR TWO PORV OPERATION (NOTE)
APo va Purx APaoa Puw Mass Setpoint Peak Setpoint Minimum ,
Input PS Pressure RCS Pressure - RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot** Pressure m
Igp_mj (psie) (osi) (psieL (psi) (psin)
_ _6,c 50 300 400 500 600 700 8(X) 900 1000 100 300 400 500 600 700 800 900 1000 Puxx - P3
- Ps - Pug NOTE: Two PORV operation is only applicable to RCS > 200 F and the mass input basis of one HHSI pump and one centrifugal charging pump with letdown isolation.
tgxcans.wp/070793 29
4 i
TABLE 5.2 (Con't)-
SUMMARY
OF MASS INPUT RESULTS FOR TWO PORV OPERATION (NOTE)
APovt, Purx APao,a Pus Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot** Pressure .
Imm). (psic) (psi) (psig) (psi) (psig)
- .._ O,0- -
200 300 400 500 6(X) :
l 700 ;
800 :
900 -
1000 .;
400 300 ,
400 500 600 700
_ 800 900 1000 .
t
- Puxx - Ps .
i y
a tgacorns.wpf070793 30 : i
1 l
TABLE 5.2 (Con't)
SUMMARY
OF MASS INPUT RESULTS FOR TWO PORY OPERATION (NOTE) .
APoveg Pyu APUNDER MN Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS Pressure RCS Rate PORV Scipoint Overshoot
- Pressure Undershoot** Pn'ssure (gnm) (psig) (nsi) (psig) (psi) (psig) b,C 800 300 400 500 600 700 800 900 1000 1200 300 400 500 600 700 800 ;
.l 900 i 1000 l
a
- Puu - P3
- P3- Pum NOTE: Two PORV operation is only applicable to RCS .>_200 F and the mass input basis of one HIISI pump and one centrifugal charging pump with letdown isolation.
v tsicauwe 10793 31
TABLE 5.2 (Con't) .
^
SUMMARY
OF MASS INPUT RESULTS FOR TWO PORV OPERATION (NOTE) - ;
APovr.a Pusx- APaoa Pam Mass Setpoint Peak Setpoint Minimum Input PS Pressure RCS - Pressure RCS Rate PORV Setpoint Overshoot
- Pressure Undershoot* * - Pressure (mm) (pMg) (psi) (psin) - (psi) (psin) .. ;
b,C '
16(X) 3(X) 4(X) 500 6(X) 7(X) 8(X) >
[
900 1(XX) _ __
1 l
Pugg
- Pg '
- P3 - Pus NOTE: Two PORV operation is only applicable to RCS > 200 F and the mass input basis of one 1 1111S1 punip and one centrifugal charging pump with letdown isolation. I i
j l
i I
ig u m.. p o793 32 )
-i
+ !
l l
~
1 l
I 1
l l
1 VI. -RESULTS OF REACTOR COOLANT '
SYSTEM HEAT INPUT TRANSIENT ANALYSES-SOUTH TEXAS UNITS I & 2 tgxccans.wpC7079) 33
i TABLE 6.1
SUMMARY
OF HEAT INPUT RESULTS FOR ONE PORY OPERATION.
APovo, Purx APaor.a Pm a Setpoint Peak Setpoint Minimum RCS/SG PS Pressure RCS Pressure - RCS Temperatures PORV Setpoint Overshoot
- Pressure Undershoot*
- Pressure
( F/ F) (psic) (psi) (psic) -- (psi) (psig)
- IC f
70/120 320 350 400 500 600 '
700 800 '
900 1000 100/150 320 350 400 P
500 600 700 800
_ 900 1000
- Puxx - P3 Ps - Puy tgxctwns wp070793 34
'I 9
v TABLE 6.1 (Con't)
SUMMARY
OF HEAT INPUT RESULTS FOR OST PORV OPERATION APoven Puxx APa.ota Pun Setpoint Peak Setpoint . Minimum '
RCS/SG PS Pressure RCS Pressurt RCS Temperatures PORY Serpoint Overshoot
- Pressure Undershoot** Pressure
(*F/ F) _ (psic) (psi) (psic) _ (psi) (psig b,c 125/175 350 ,
400 500 600 700 800 900 1000 150/200 320 :
350 400 500 '
600 7(X) 800 9(X) 1000 Py4x - P3 Ps - Pun ista = + 070793 35
9 TABLE 6.1 (Con't)
SUMMARY
OF flEAT INPUT RESULTS FOR ONE PORV OPERATION APoveg Puxx APaosa Pun -
Setpoint Peak Setpoint Minimum i
)
RCS/SG PS Pressure RCS Pressure RCS .
l Temperatures PORV Setpoint Overshoot
- Pressure Undershoot*
- Pressure l
( F/ F) (psin) (psi) (psin) (psi) (psin)
}-
170/220 350
- sc 400 500 600 700 800 900 1000 200/250 320 400 500 600 7(X)
'4 800 {
9(X) l l
1000 !
- Puu - P3 4
" P -3 Pun l
l
'I 1
)
l l
ignamns.wp/070793 36 ,
J
- - _ - - - - _ _ _ - _ _ - _ _ - _ _ - . - - _ _ - - - - _ _ - _ _ _ _ _ _ _ _ _ _ _ . - _ - - _ - _ _ . _ - - -b
TABLE 6.1 (Con't)
SUMMARY
OF HEAT INPUT RESULTS FOR OhT PORV OPERATION APovta Purx APowot, Pym Selpoint Peak Setpoint Minimum RCS/SG PS Pressure RCS Pressure RCS Temperatures PORV Setpoint Overshoot
- Pressure Undershoot*
- Pmssure
( F/ F) (psic) (psi) (psig) (psi) (psic)
D,C 250/300 320 400 500 600 700 >
800 900 1000 300/350 320 400 f
500 600 700 800 900 1000
- Puxx - Ps
- -P-Pm3 y igaconsupmo792 37
?
TABLE 6.2
SUMMARY
OF HEAT INPUT RESULTS FOR TWO PORV OPERATION (NOTE)
APoys, Puxx APusosa Puu Setpoint Peak Setpoint Minimum RCS/SG PS Pressure RCS Pressure RCS-Temperatures PORV Setpoint Overshoot
- Pressure Undershoot** Pressure
( F/ F) (psic) (psi) . (psig) (psi) (psic) 200/250 320
_b;c 400 500 600 700 800 900 1000 250/300 320 400 500 600 700 800 900 1000
- Puxx - P3
- P 3 - Pug NOTE:
Two PORV operation is only applicable to RCS 1200 F and the mass input basis of one -
IIHSI pump and one centrifugal charging pump with letdown isolation.
incans womo793 38
i TABLE 6.2 (Cont'd) -
SUMMARY
OF HEAT INPUT RESULTS -
FOR TWO PORV OPERATION (NOTE)
APovta Puu APnoca Puw .,
Serpoint Peak Setpoint Minimum RCS/SG PS Pressure RCS Pressure RCS Temperatures PORV Setpoint Overshoot
- Pressure Undershoot** Pressure ,
( F/ F) (psie) (psi) (psie) (psi) (psic)-
- /3 6 300/350 320 400 500 600 i 700 800 '
900 1000 h
- Puu - P3
- P 3- Pum NOTE: Two PORV operation is only applicable to RCS > 200 F and the mass input basis of one HHS1 pump and one centrifugal charging pump with letdown isolation.
4 tgxcoms. wpm 0793 39
q
.4.
J VII. SITTPOINT DETERMINATION
=A. BASES Specification delineated in Section IV.
B. LEGEND APPLICABLE TO GR APHICAL ALGORITIIMS Figures 7.2 through 7.9 show the graphical algorittuns used in the development of the COMS setpoints. Included on these curves are:
7 Maximum pressure limit (either Appendix G limit minus pressure differential or 800 psig maximum pressurizer pressure for PORV discharge piping limits). For when the Appendix G limit applies, the maximum limit was based upon luth a maximum of 2 RCP operating and a maximum of 4 RCP operating.
Minimum pressure limit (minimum pressure to ensure 200 psid differential pressure acmss reactor coolant pump seals).
Locus of pressure overshoots due' to design basis mass injection transient with one PORV operation.
Locus of pressure overshoots due to design basis heat injection transient with one PORV operation. J Locus of pressure undershoots due to limiting mass injection transient. For temperatures t
below 200 F, one PORV operation is considered; for temperatures above 20(FF, two PORV operation is considered. ;
Locus of pressure undershoots duc to design basis heat injection transient. For temperatures below 20(FF, one PORV operation is considered; for temperatures above 20TF, .
two PORV operation is considered. i 1
i The pressure range over which setpoints can be developed is based on (1) the intersection of l
the lower of either the mass or heat injection'undershoot curve with the RCP seal limit (lowest permitted setpoint) and (2) the intersection of the higher of either the mass or heat injection
. overshoot curve with the maximum pressure limit (highest permitted setpoint).
I i
-I
. tpcana.wpO70793 40 l
')
n:
C. DATA UTILIZED
- 1. Mass input .
- a. Parametric Correlations for South Texas 1 & 2 4
As is noted in Tabic 5.1 for one PORV operation, LOFFRAN runs have given unrealistic large overshoots which occur for the cases where the maximum mass injection mte exceeds the flow capacity of a fully open PORV at its setpoint. This is -
because LOFTRAN utilizes a constant mass injection rate throughout the transient. In other words,it does not account for the fact that the ability to inject mass into the system decreases as system pressure increases. In actuality, as the system pressure .
reaches the valve setpoint, the PORV opens fully and discharges an amount of fluid equal to its capacity at the set pressure. For the mass input design basis of one lillSI pump and one centrifugal charging pump with letdown isolation, if the valve capacity is less than the mass injection rate, the system pressure will continue to increase along the dotted line in Figure 7.1. This will increase the valve Dow and decrease the mass :
input rate until an equilibrium is reached at [ P'. Some :i pressure overshoot could occur here due to the pressure sensing delay time and the ;
valve stroke time. LOFTRAN runs indicate that a maximum overshoot of [ f' psi l
for a mass injection rate of [ l* gpm and valve setpoint at [ f* psig. For ,
conservatism, a maximum overshoot of [ 'f' psi is used and the Pmx for setpoints less than I f* psig should be no greater than [ f* psig overshoot) which is below the 800 psig PORV piping force requirement (limiting maximum allowable pressure for RCS temperatums when this tuass imput design basis is applicable).
The mass input data of Section V, attributable to one PORV operation,is plotted in Figures 7.10 and 7.12. Figure 7.10 covers the undershoot for mass input rates from 50 to 1600 ppm. Figure 7.12 covers the overshoot for mass input rates from 0 to 1600 gpm; however, it does not include the overshoot for setpoints less than [ f* psig with combined mass input from both a charging and an SI pump. The Pmx should be
[ f' psig for any setpoint less than [ P' psig as it is explained in the above paragraph. The mass input undershoot, attributable to two PORV operation, is plotted in Figure 7.11. Setpoint parametric correlations of setpoint overshoot APom = Pmx-Pmam and setpoint undershoot APosna = Pena - Pms were developed to facilitate drawing die locus of maximum RCS pressures produced by Mi transients and the locus tpuuns.widr/0793 4]
1 l
i of minimum RCS pressures pmduced by the M1 transients as a function of setpoint (Pscrmm). As noted in Section 11, the range of mass input rates analyzed (50 gpm to 1600 gpm) was sufficiently broad to envelope the maximum possible mass injection .
rates.
\
- b. Development of the Algorithmic RCS Pressure Extreme Curves Table 7.1, applicable to RCS < 2(XPF, summarizes the development of the M1 maximum and minimum RCS pressure locus curves for letdown isolation with one centrifugal charging pump operating. Table 7.2, applicable to RCS 2 200 F, summarizes the development of the MI maximum and minimum RCS pressure locus curves for SI actuation with one high head Si pump plus one centrifugal charging pump with letdown isolation. In Table 7.2, the maximum MI RCS pressure is ,
produced by one PORV operation and the minimum MI RCS pressure is produced by two PORV operation. For setpoints less than [ f' psig, the Psux for one valve - '
operation is [ f' psig and the AP vna o is calculated as Psax minus Pscrnar. In the development of the RCS pressure overshoot curve, the generalized correlations of.
Figure 7.12 were adjusted to account for specific MI rates as prescribed in Figure 2.1 for one centrifugal charging pump operation at RCS temperature < 200 F, and the generalized correlations of Figure 7.12 were adjusted to account for the specific MI 'l rates as prescribed in Figure 2.3 for one high head Si pump and one centrifugal charging pump operation at RCS temperature 2 20(FF. The minimum RCS pressure curve was developed from Figure 7.10 for RCS temperature < 20(PF and from Figure ,
7.1i for RCS temperature 2200 F using the largest APosnca expected to occur for a prescribed setpoint over the entire Mi range (50 gpm to 1600 gpm).
- 2. IIcat input i
The data of Table 6.1 of Section V, attributable to one PORV operation, was used directly in determining the APovoa and APusnex values plotted on Figures 7.2 through 7.6 for RCS ~
< 2(KFF, and in detennining the APoyng values plotted on Figures 7.7 through 7.9 for RCS 2 20(FF. The APesneg values plotted on Figures 7.7 through 7.9 for RCS 2 2(XFF was detennined by the data of Table 6.2 for two PORV operation. :
a
-l 1
In developing the PORV setpoint for a given measured RTD tempemture, one must take into.
account the heat transport effect. If a heat input event were to occur, the cold leg temperature would rapidly rise to that corresponding to the steam generator, while the vessel would still be i
tpcomshp'LT/0793 4$2 l
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1 W *__.a - - + _ =
,w s
at the RCS temperature which existed prior to the transient. Therefore, the PORV setpoint
- must be defined so that it corresponds to the Appendix G limit at the vessel temperature, not ,
the measured ETD temperature. As described in Section III, it was assumed that the RTD was measuring a temperature 77 F higher than the vessel (50'F due to primary to secondary temperature difference plus 27 F instrument error).
D. ALGORITHM APPLICATION Figures 7.2 through 7.9 illustrate the application of the algoritlun described in WCAP 10529, Section 6 to South Texas Units 1 & 2.
There are a few intemtediate temperature ranges for which the pressure limits indicated on Figures i
7.2 through 7.9 are not valid. These ranges are as follows:
- 1) Temperatures just below 120 F: The 120 F value is when the pressure limit switches from a flange limit of 621 psig to the Appendix G limit applicable to the vessel (see Figure 4.1) .
Therefore, for temperatures <!20 F, the limits shown on Figure 7.3 are applicable; at a temperature of 120+ F, a Appendix G limit of 841 psig applies.
- 2) Temperatures just below 200 F: Figure 7.7 is applicable for the case of 200 F and just above. where the mass input design basis has switched to being a combination of a charging plus a safety injection pump. Just below 200 F, the mass input design basis is just a single charging pump. and the mass injection overshoot /undershoot values would be those shown on Figure 7.6. Likewise, just below 200 F, the heat injection undershoot would be most representative of Figure 7.6 rather than 7.7 since the two PORV serpoints can be staggered suffliciently to preclude dual PORV actuation for a mass input design basis of just a single l charging pump. ,
t The maximum underpressure ( APu snea) utilized for the development of the locus of minimum RCS pressure produced by Mi transients for RCS temperature < 200 F is obtained from Figure 7.10 for one PORV operation and for RCS temperature 2 20(FF is obtained from Figure 7.11 for two 4
PORV operation. The maximum overpressure ( APova) utilized for the development of the locus of maximum RCS pressures produced by Mi transients is obtained from Table 7.1 for RCS -
temperature < 2fXFF and from Table 7.2 for RCS temperature 2 20(FF. These APosona and l
APovry values are consistent with all nonnal and abnonnal (infrequent) modes of mass input l
)
(Section II. E). These values also take into account the maximum expected injection rate provided I in Figure 2.1 for RCS temperature < 2(KFF or in Figure 2.3 for RCS temperature 2 20(FF.
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1 0
Algorillun application is extended to reflect the specific requirements of South Texas Units 1 & '2 l as listed in Section IV. E. If the range of pennissible setpoints falls within the range of potential RilR valve opening as is the case at lower RCS temperatures, then potential operafon of both the PORV and RilR valves must be expected.
It should be noted that while pressure measurement uncenainties are not included in the setpoint analysis, temperature uncenainties are This is because the temperature uncenainties can readily be accommodated without adversely affecting plant operation, unlike the pressure uncertainties which can severely limit the pressure range during heatup/cooldown, in~ addition, the design basis heat input transient is the inadvertent start of one reactor coolant pump when the RCS has been cooled:
down to an extent such that the steam generators are 50 F hotter than the RCS. When the one-RCP is staned, the wide-range temperature transmitters will be measuring the wanned RCS fluid -
temperature, which is greater than die vessel temperature. Therefore the setpoints should re11ect the temperature difference between the measured Huid temperature and the reactor vessel temperature; for conservatism the full 50T is used besides the 27 F instrument uncertainty, j i
The setpoint development considers two possible modes of operating the reactor coolant pumps.
The first is a maximum of two RCPs in operation: the second is a maximum of all four RCPs in operation. Separate setpoints were developed for both cases. The maximum pressum limit shown on Figures 7.2 through 7.9 reDects this pump limitation. It should be noted, however, that once the 800 psig pressuriter PORV piping limit is in effect, there is no restriction on RCP operation, since in all cases the pressurizer pressure is less dian that existing in the RCS.
The heat injection transient is defined as an inadvenent start of a single RCP fmm a complete -
natural circulation condition; RCS cooling is through the RHR system, and as the RCS cools down the steam generators remain at a relatively high temperatum. Therefore, the maximum pressure differential that need be considered from the W/R pressure transmitters to the reactor vessel (where Appendix G applies) is only the two RCP case (this brackets the actual case of a single RCP ,
operating).
The procedure for the development of the setpoints ihr the two PORVs was as follows: ;
- 1) Detennine the nominal maximum pressure limit vs. RCS temperature. This is shown on Figures ]
7.2 through 7.9 as the minimum applicable limit based upon:
{
t Two RCP operation
- Four RCP operation PORV piping limit ,
-1 i
igmmwpAno7% 44 I
1
[_ x i4, s.
- 2) Shift the pressure vs. temperature limits determined in (1) to the right by 27*F to account for the generic temperature measurement uncenainty.
f
- 3) Detennine the maximum allowable pressure setpoint for the mass' injection transient. This is die intersection of the mass input overshoot curve (higher curve designated "Ml" on Figures 7.2 - 7.9) with the pressure limit defined in (2) above.
- 4) Shift the pressure vs. temperature limits detennined in (1) to the right by 77 F ( 27 F temperature measurement uncertainty plus 50 F for the heat injection design basis). For this case, the 4 RCP case is not considered, since the design basis is the inadvertent start of a single RCP.
- 5) Determine the maximum allowable pressure setpoint for the heat injection transient. This is the intersection of the heat input overshoot curve (higher curve designated "HI" on Figures 7.2 - 7.9) with the pressure limit defined in (4) above.
- 6) Maximum allowable setpoint is the locus of the minimum of (3) and (5).
With the maximum allowable setpoints defined, the setpoints to be recommended for -
implementation in the process equipment can then be detennined. This is done in the following manner: ,
a) The higher PORV setpoint is lirst detennined (called PORV #2). This is done by choosing setpoints that are close to the maximum allowable values at an even multiple of 5 psi. For those.
areas where the maximum allowable setpoint changes in a step manner, the implemented setpoi_nt change is limited to a [ ]*# psi / F ramp due to the generic limitations of the function generator process card.
b) The PORV # 1 setpoint is then chosen by using the mass injection overshoots fnnn Tables 7.1 and 7.2 and the heat injection overshoots from Tables 6.1 and 6.2. The PORV #1 setpoint is chosen as an even multiple of 5 psi such that the difference between the two PORY setpoints is greater than the maximum overshoot resulting from either the mass injection or the heat injection transient at the chosen RCS temperatum. This is an attempt to minimize the potential.for actuation of both PORVs simultaneously.
On reviewing Figures 8.3 and 8.4 and Table 8.1, it can be seen there are certain temperature regions below 197 F where the Maximum Allowable setpoint decreases for increasing RCS temperature. For the purposes of setpoint implementation, it was decided that a " negative slope" tumuur,nrio793 45
1 for the setpoints should not be included, since it could result in a potential inadvertent COMS -
actuation during RCS heatup conditions. The setpoint program was selected such that the PORV setpoints are either constant or increasing with increasing RCS temperature.
In the selection of the implemented setpoints, while the Maximum Allowable values shown on .
Figures 8.3 and 8.4 were used for the PORV #1 setpoint and the pressure overhoots fann Tables -
6.1,6.2,7.1. and 7.2 were used to detennine the amount the PORV #2 setpoint had to be below the PORV #1 setpoint, some additional conservatism was added. This wa~ to select PORV pressure.
setpeints that are even multiples of 5 psi and temperature setpoints that are even multiples of 10 F in order to provide an case of setpoint scaling and implementation. At a minimum. this resulted in -
the PORV setpoints being moved to the right of the Maximum Allowable values by 3 F (i.e.,
197 F becomes 200 F) ami down from the Maximum Allowable values by 6 psi (i.e.,556 psig-becomes 550 psig).
f f1Lcorns.w}VU70791 46 s -
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RCS INJECTION VS PORV RELIEF FLOW CHARGING PLUS S1 PUMP, ONE PORV h,c f
O.
b m
O E
O l-3 9
FLOW FROM CHG , St PUMP PORV FLOW Figure 7.1 ipem u u p w o793 47
RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 70 DEG F b,c l
b G5 b
Lu C
D (D
(D UJ
[
O_
(D O
C ,
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Figure 7.2 ig n ou.wn'ii7079 48 ;
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RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 100 DEG F b, e r-
~
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55 l b: !
wi 1i ai cn ' ,
en W i
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E PORV SETPOINT PRESSURE (PSIG)
Figure 7.3 incum-parno93 49
RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 125 DEG F b,cL 6
55 k
w E
D CD CO ,
C CL CO O
C
~
~
Figure 7.4 ina n, wom o792 50
RCS PRESSURE EXTREMA VS 'JORV SETPOINT RCS TEMP = 150 DEG F b, C 05 b
w 1
D (D
(D W
C Q
CD O
C PORV SETPOINT PRESSURE (PSIG)
Figure 7.5 igxnommntman 51
a RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 170 DEG F b,c
~
7
^
O 55 w
T D
Ln V) t W
C !
1 i CD o !
e i i
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),
Figure 7.6 igxumsmynom 52
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RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 200 DEG F b, c 4
i t
i
^!
05 CL
- i W!
EI D
CD i CD I W'
C CL CD O
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~
Figure 7.7 incans..pino793 53
RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 250 DEG F h>C I
O G5 h
LIJ E
D CD CD uJ C
CL CD O
C PORV SETPOINT PRESSURE (PSIG)
Figure 7.8 tgicutts.wpA00793 54
RCS PRESSURE EXTREMA VS PORV SETPOINT RCS TEMP = 300 DEG F 6,c GT ui k
w C
D in CD w
1 O_
(D O
C
~ ~'
Figure 7.9 incmuunm o793 55
RCS PRESSURE U' SHOOT VS. MASS INPUT ONE PORV OPERATION b,' C ;
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b MASS INPUT RATE (GPM)
Figure 7.10 inmnsyntno793 - 56
i RCS PRESSURE U' SHOOT VS. MASS INPUT ,
TWO PORV OPERATION .
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=
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f-O O
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Q Z
D W
T D
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W
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MASS INPUT RATE (GPM)
Figure 7.11 i
1 incans.wpro70793 57
RCS PRESSURE O' SHOOT VS. MASS INPUT ONE PORV OPERATION b,c
=
0) b l--
O O
I U)
E W
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V)
UJ C
Q.
V)
O E
~ ~
FLOW (GPM) l l
l l
Figure 7.12 j ig m m w gi70793 58
4 TABLE 7,1 DEVELOPMENT OF THE MASS INPUT RCS PRESSURE EXTREMES FOR RCS TEMPERATURE < 200 F Maximum PS Credible C"* C)
APova Psu APesna"'" Psi:s Setpoint MI Rate @ Max MI of from of Pressure @ PS* Rate Algorithm Fig. 7.10 Algorithm (psic) (ppm) (psi) (psic) (psi) (psic) b,C 2(X) 300 4(X) 5(N) 6(X) 7(X) 8(X) 90()
1(XX)
(1) Based on Figure 2.1 (2) .
AP,.. P,,, APm,, and P , are based on one PORV operation.
(3) APm, = P,, - Ps: AP,, = Ps - P , ,
1 i
tgxctum wp't170791 59
~ - . . . . . - - - .. . . .. . . --
4 l
TABLE 7.2 DEVELOPh1ENT OF THE htASS INPUT RCS PRESSURE EXTREh1ES FOR RCS TEh1PERATURE > 200*F, F
Maxitnum PS Credible 0"* Ps,4x
- APane,0"5) Ps,
. APo vta Setpoint MI Rate @ Max Mi of from .. o f Pressure @ PS") Rate Algoritlun Fig. 7.11 Algorillun (psin) (com) (psi) (psic) (psi) (psin)
>> 0-. .
3(X) 400 SfX) 6(X) 7(X) 800 900 t
1(X)O (1) Based on Figure 2.3 (2) See Section Vll.C.I.a for detailed explanation. -
(3) APm , = P , - PJ AP,,,, = P, - P , ;
(4) AP,,,, and P , is based on one PORV operation.
(5) AP, , and P., is based on tw'o PORV operation.
in m m + g no793 60
.~, _ _ . _ . , - . . _ . . . _ . . . _ . . - . __.n _ . . _ . ,
v Vill. SETPOINT PROGRAM The pressure limits and the maximum allowable PORV setpoints are shown on Figures 8.1 and 8.2 for the two RCP operation limitation and four RCP operation limitation, respectively. l l
From these figums, the maximum allowable selpoints to be included in the Technical Specifications were detemiined and are shown on Figures 8.3 and 8.4 and in Table 8.1 for the l two RCP pump operation cases.
For hardware application, the total number of linear segments is limited to a total of 8, whicli are defined by a total of 9 bmakpoints. Linear interpolation is used to calculate valve setpoints between the breakpoints defining the individual line segments. A listing of the -
PORV setpoints for the 2 RCP pump limitied operation and the 4 RCP pump limited operation are included in Tables 8.2 and 8.3, respectively.
i l
Igxmns.wpV70793 ' 6}
. . .. . . . . . ._ - .- ..__ _ _ __ _ _ _. - - . __ __ ~ ._._. . - _ _ _ . _ _ _ . _
e TABLE 8.1 i
i MAXIMUM ALLOWABLE COLD OVERPRESSURE MITIGATION SYSTEM SETPOINTS ;
l 2 RCP Operation _4 RCP Operation ,
RCS Temperature Max. PORV setpoint RCS Temperature Max. PORV Setpoint
( F) (psig) ( F) (psig) 70 571 70 -522 1 177 564 147 522 197 556 148 567 198 737 197 556 -
350 737 198 737 350 737 s
a
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y- ew-- y---y -r-- 9,.. . .w r - -,.4--. . - - - - . . . -4 w ---
, l TABLE 8.2 .
l
- REVISED COLD OVERPRESSURE MITIGATION SYSTEM SETPOINTS i
- r. ;
2 RCP PUMP OPERATION -)
l PORV #2 PORV #1 Indicated RCS Temp (*F) Setpoint (psig) Setpoint (psin)
'l 70 550 510 140- 550 510' 180 550 510 200 550 510 J 210 640 590 220 730 660 245 730 660 380 730 660 450 2350 2350 i
i TABLE 8.3 REVISED COLD OVERPRESSURE MITIGATION SYSTEM SETPOINTS 4 RCP PUMP OPERATION l
PORV #2 PORV #1-Indicated RCS Temp ( F) Setpoint (psin) Setpoint (psic) 70 515 475 140 515 475 i I80 515 475 200 515 475 210 640 590 220 730 660.
245 730 660 380 730 660 450 2350 2350 i
.. IfXCE uns.wpTJ7079.1 63 j
d MAXIMUM ALLOW PORV SETPOINT- 2 RCP MI AND HI MAX. ALLOW VS. PR. LIMIT 850 . . .
800------- - -
--:n er 0; :6 = c I u e--
- m-6 6-4 :
- 's N 750- - - -
N-+ =- o
- s-s ti. :. i :. :.
0 700- --- ---
m . . . .
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m 650 ------ -
a . . .
w . . .
g . . , , .
uJ600 -
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C./r%~i 0 550 -----
c 500-------- -: - -- - - - - - -:- - - - - - - - - - -: - - - l- - - - - -
450 :
e s . s s 400 : ! !
l l l l l h .l 0 50 100 150 200 250 300 350 400 INDICATED RCS TEMPERATURE (DEG F)
+ MAX LIMIT + MI MAX S/P + HI MAX S/P Figure 8.1 tpmnopu70791 ()4 ,
MAXIMUM ALLOW PORV SETPOINT- 4 RCP MI AND HI MAX. ALLOW VS. PR. LIMIT 850 . . . . q 800 ----- -.: -
- se-Nn+s-m
= i. n s -
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D-----H} --U .
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500--- - ---
f 4 .
450 -
a i y a 400 l l F. l l l l l : 1 1 0 50 100 150 200 250 300 350 400 INDICATED RCS TEMPERATURE (DEG F)
+ MI MAX LIMIT HI MAX LIMIT
-o- MI MAX S/P -+- HI MAX S/P Figure 8.2 inum.pano791 65
MAXIMUM ALLOWABLE PORV SETPOINT '1 l
2 RCP OPERATION 800 , ,
i
.t . . , 9 a. 4 .
I I t g ....................
cn , , ,
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e ,
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oa 600 ---
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y ..,-,w 7
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2 . . . .. .
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500 I i i i: ,i ,i i. 1 . ; ,ii,;i4 6 i;.ii,jiiii i i i ,
4 50 100 150 200 250 300 350 400 MEASURED RCS TEMPERATURE (DEG F)
MAX LIMIT Figure 8.3 incum.wivwmv3 66
MAXIMUM ALLOWABLE PORV SETPOINT 4 RCP OPERATION 800 , ,
. , , . . L . 4 . ,
A ,
.........4 g
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av
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O . - .- . ... . - . . ... ......... --. .. -.
a ,
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' (D . . .... ......... . . . . . . . . . .... . . .......
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500 l i ll l l : : : ,l'!l!! l ll l'lll: lll l4 50 100 150 200 250 300 350 400' MEASURED RCS TEMPERATURE (DEG F)
- MAX LIMIT Figure 8.4 apuun.u puro792 67
...--- - -. --- ..-- . .~._.-
, REFERENCES R
b
! 1. WCAP-10529, February,1984 (non-proprietary)
! 2. CST &S-CSDT-104,1/6/86 (p.uprietary)
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APPENDIX A IIEATUP AND COOLDOWN LIMIT CURVES-FOR NORM AL OPERATION FOR .
SOUTH TEXAS UNITS 1 AND 2 ,
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i TABLE OF CONTENTS Section Title Page-LIST OF ILLUSTRATIONS A-2 LIST OF TABLES ' A-2 1-A-1 INTRODUCTION . A-3 -
A-2 FRACTURE TOUGHNESS PROPERTIES A-3 A-3 CRITERIA FOR ALLOWABLE PRESSURE, TEMPERATURE A-4 RELATIONSHIPS A-4 HEATUP AND COOLDOWN PRESSURE-TEMPERATURE LIMIT A-6 CURVES A-5 CALCULATION OF ADJUSTED REFERENCE TEMPERATURE A-7 A-6 REFERENCES A-14 ATTACllMENT Al; - DATA POINTS FOR HEATUP AND COOLDOWN CURVES A-15' r
f h
a tpums.wsno793 A-1 ;
LIST OF ILLUSTRATIONS Fleure Title Pace i t
A-1 South Texas Units 1 and 2 Reactor Coolant System Steady State Heatup/ A 13' Cooldown Limitations (Heatup/Cooldown rate of O'F/hr) Applicable for the First 32 EFPY (without margins for instrumentation errors)
LIST OF TABLES Table Title Pa.ce A-1 South Texas Unit i Reactor Vessel Toughness Table A9' (Unirradiated)
A-2 South Texas Unit 2 Reactor Vessel Toughness Table A- 10 (Unirradiated) i A-3 Summary of Adjusted Reference Temperatures (ART's) at 1/4-T A-11 and 3/4-T Locations for 32 EFPY for South Texas Units I and 2 A-4 Calculation of Adjusted Refemnce Temperatures at 32 EFPY A-12 for the Limiting Reactor Vessel Material for South Texas Units 1 and 2 -
South Texas Unit 1 Intermediate Shell Plate, R1606-3
\
- inmni.wpmo793 A-2
A 1. INTRODUCTION Heatup and cooldown limit cmves are calculated using the most limiting value of RTsar (reference nil-ductility temperature) corresponding to the limiting beltline region material for the reactor vessel.
The most limiting RTstn of the material in the core region of the reactor vessel is detennined by using the unirradiated reactor vessel material fracture toughness properties and estimating the radiation-induced ARTsty. The unirradiated RTsty is designated as the higher of either the drop weight nil-ductility transition temperature (NDTT) or the temperature at which the material exhibits at least 50 ft-lb of impact energy and 35-mil lateral expansion (nonnal to the major working direction) minus WF.
RTmg inemases as the material is exposed to fast-neutron radiation. Therefore, to find the most limiting RTmg at any time period in the reactor's life, ARTmy due to the radiation exposure associated with that time period must be added to the original unirradiated RTyg. The extent of the shift in RTug is enhanced by certain chemical elements (such as copper and nickel) present 'n i reactor vessel steels. The Nuclear Regulatory Commission (NRC) has published a medmd for predicting radiation '
embnttlement in Regulatory Guide 1.99 Rev. 2 (Radiation Embrittlement of Reactor Vessel ,
Materials)I^". Regulatory Guide 1.99, Revision 2 is used for the calculation of ART values at 1/4-T and 3/4-T locations. T is the thickness of the vessel at die beltline region measured from the clad / base -
metal interface.
The pressure-temperature limit curves in this report represent the reactor coolant system pressure at the limiting beltline region of the reactor vessel. Since pressure readings are measured at other locations than the limiting beltline region, the pressure differences between the pressure transmitter and the limiting beltline region must be accounted for when using the pressure-temperature limit curves herein.
A-2. FRACTURE TOUGilNESS PROPERTIES f
The fracture-toughness properties of the ferritic material in the reactor coolant pressure boundary are detennined in accordance with the NRC Regulatory Standard Review Plan'^U. The pre-irradiation fracture-toughness properties of the South Texas Units 1 and 2 reactor vessel are presented in Tables A 1 and A 2.
inconn.womo793 A3
f A-3. CRITERIA FOR ALLOWABLE PRESSURE-TEMPERATURE RELATIONSIIIPS
'l '
The ASME approach for calculating the allowable limit curves for various heatup and couldown rates specifies that the total stress intensity factor, K ,i for the combined thennal and pmssure stresses at any -
time during heatup or cooldown cannot be greater than the reference stress intensity factor, Km, for the i 1
metal temperature at that time. Ky is obtained from the reference fracture toughness curve, defined in -l l
Appendix G of the ASME Code ^3' The Km curve is given by the following equation:
Ka-i 26.78 + L223
- e i""*""** (1) where Km = reference stress intensity factor as a function of the metal temperature T and the metal reference nil-ductility temperature RTsar Therefore, the governing equation for the heatup-cooldown analysis is defined in Appendix G of the ASME Code i^31 as follows:
C
- K 3, + Krr 5. Km (2) where Kni = stress intensity factor caused by membrane (pressure) stress I
J stress intensity factor caused by the thennal gradients I Krr =
Km = function of temperature relative to the RTsm of the material C = 2.0 for Level A and Level B service limits C = 1.5 for hydrostatic and leak test conditions during which the reactor core is not critical l l
- At any time during the heatup or cooldown transient, Km is detennined by the metal temperature at the.
tip of the postulated flaw, the appropriate value for RTsm, and the reference fracture toughness curve.
The thennal stmsses resulting from the temperature gradients through the vessel wall are calculated and then the corresponding (thennal) stress intensity factors, Kn, for the reference flaw are computed.
i in u ms.v,pv70791 A-4 I i
_ , .fi _ _ _, . .__ - _ _ _. _ _ , - - _ _ _ _ _ _ _ - _ _ _ _
r From Equation 2, the pressure stress intensity factors are obtained and, fmm these, the allowable .
pressures are calculated.
For ' Jculation of the allowable pressure versus coolant temperature during cooldown, the reference flaw of Appendix G to the ASME Code is assumed to exist at the inside of the vessel wall.
During cooldown, the controlling location of the flaw is always at the inside of the wall because the thennal gradients produce tensile stresses at the inside, which increase with increasing cooldown rates.
Allowable pressure-temperature relations are generated for both steady-state and fmite cooldown rate situations. From diese relations, composite limit curves are constructed for each cooldown rate of interest.
The use of the composite curve in the cooldown analysis is necessary because control of the cooldown procedure is based on the measurement of reactor coolant temperature, whereas the limiting pressure is actually dependent on the material temperature at the tip of the assumed flaw, During cooldown, the 1/4-T vessel location is at a higher temperature dian the fluid adjacent to the vessel ID. This condition, of course, is not true for the steady-state situation. It follows that, at any given reactor coolant temperature, the AT developed during cooldown results in a higher value of Km at the 1/4-T location for fhute cooldown rates than for steady-state operation. Furthennore, if conditions exist so that the increase in K a i exceeds Krr, the calculated allowable pressure during cooldown will be greater than the steady-state value.
The above procedures are needed because there is no direct control on temperature at the 1/4-T location and, therefore, allowable pressures may unknowingly be violated if the rate of cooling is
' ecreased at various intervals along a cooldown ramp. The use of the composite curve climinates this d
problem and ensures conservative operation of the system for the entire cooldown period.
Tlure separate calculations are required to detennine the limit curves for finite heatup rates. As is j done in the cooldown analysis, allowable pressure-temperature relationships are developed for.
steady-state conditions as well as finite heatup rate conditions assuming the presence of a 1/4-T defect at the inside of the wall. The heatup results in compressive stresses at the inside surface that alleviate the tensile stresses produced by internal pressure. The metal temperature at the crack tip lags the
, coolant temperature; therefore, the Km for the 1/4-T crack during heatup is lower than the Km for the
} I/4-T crack during steady-state conditions at the same coolant temperature, During heatup, especially
- at the end of the transient, conditions may exist so that the effects of compressive themial stresses and lower Krg's do not offset each other, and the pressure-temperature curve based on steady-state
- conditions no longer represents a lower bound of all similar curves for fmite heatup rates when the inninuyplo707n - A-5
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l 1/4-T flaw is considered. Therefore, luth cases have to be analyzed in order to ensure that at any coolant temperature the lower value of the allowable pressure calculated for steady-state and finite heatup rates is obtained.
The second portion of the heatup analysis concems the calculation of the pressure-temperature limitations for the case in which a 1/4-T deep outside surface flaw is assumed. Unlike the situation at the vessel inside surface, the themial gradients established at the outside surface during heatup produce stresses which are tensile in nature ami therefore tend to reinforce any pressum stresses present. These thennal stresses are dependent on both the rate of heatup and the tinie (or coolant temperature) along the heatup ramp. Since the thermal stresses at the outside am tensile and increase with increasing heatup rates, each heatup rate must be analyzed on an individual basis.
Following the generation of pressure-temperature curves for both the steady state and finite heatup rate situations, the Onal limit curves are produced by constmeting a composite curve based on a point-by-point comparison of the steady-state and finite heatup rate data. At any given temperature, the allowable pressure is taken to be the lesser of the three values taken from the curves under con. sideration. The use of the composite curve is necessary to set conservative heatup limitations because it is possible for conditions to exist wherein, over the course of the heatup ramp, the controlling condition switches from the inside to the outside, and the pressure limit must at all times be based on analysis of the most critical criterion.
Finally, the 1983 Amendment to 10CFR50M has a rule which addresses the metal temperature of the closure head Dange and vessel Gange regions of both South Texas Unit I and South Texas Unit 2, since the heatup and cooldown curves are applied to both units. This rule states that the metal temperature of the closure flange regions must exceed the material unitradiated RTun7 by at least 120*F for nonnat operation when the pressure exceeds 20 percent of the preservice h/drostatic test pressure (621 psig for South Texas Units I and 2).
Table A-1 indicates that the limiting unirradiated RTsn7 of O'F occurs in the vessel Gange of South Texas Unit 1, so the minimum allowable temperature of this region is 120*F. This limit is shown bi Figure A-1 whenever applicable.
A-4. IIEATUP AND COOLDOWN PRESSURE TEMPERATURE LIMIT CURVES l,
Pressure-temperature limit curves for normal heatup and cooldown of the primary reactor pressure vessel have been calculated for the pressure and temperature in the reactor vessel beltline region using the methods discussed in Section A-3. Figure A-1 presents the heatup/cooldown curves using a 1
i
'fp 6 ws y w o793 A-6 i 1
1
. .. . , . - . . - . . . . _;. J
i 1 I l
y heatup/cooldown rate of 0*F/hr applicable for the first 32 EFPY. ,
Allowable combinations of temperature and pressure fbr specific temperature change rates are below and to the right of the line,' line shown in Figure A-1. This is in addition to other criteria which must be met before the reactor is made critical.
i Figure A-1 defines limits for ensuring prevention of nonductile failure for South Texas Units I and 2 2
reactor vessels.
The data points used to develop the heatup and cooldown pressure-temperature limit curves shown in Figure A-1 are presented in Attachment Al. ;
i A-5. CALCULATION OF ADJUSTED REFERENCE TEMPERATURE Fnnu Regulatory Guide 1.99 Rev. 2 I^U the adjusted reference temperatun' (ART) for each material in - j the heltline is given by the following expression:
ART = Initial RTmy + ARTug + Margin (3)
Initial RTmg is the reference temperature for the unirradiated malerial as defined in paragraph NB-2331 of Section III of the ASME Boiler and Pressure Vessel Code. If measured values .of initial
-RTsny for the material in question are not available, generic mean values for that class of material may l be used if there are sufficient test results to establish a mean and standard deviation for the class.
.1
.I ARTyg is the meu value of the adjustment in mference temperature caused by irradiation and should l
be calculated as follows: 1 ARTu - [CFJ
- f("""""8 0 (4)
To calculate ARTgy at any depth (e.g., at 1/4-T or 3/4-T), the following formula must first be used to anenuate the fluence at the specific depth.
fone n = fm ,,
- e * (5) where x (in inches) is the depth into the vessel wall measured from the vessel clad / base metal incmu.wtw70703 A-7. .
i'
'l l
interface. The' resultant fluence is then put into equation (*) to calculate ARTsm at die specific' depth.
CF (*F) is die chemistry factor, obtained from Tables in Reference Al, using the mean values of the I copper and nickel content as reported in Tables A-1 and A-2. All materials in the beltline region of South Texas Units 1 and 2 were considered in determining die limiting material. The results of the ART's at 1/4-T and 3/4-T are summarized in Table A-3. From Table A-3, it can be seen that the limiting material is the South Texas Unit 1 intennediate shell plate, R1606-3 for heatup and cooldown curves applicable up to 32 EFPY. Sample calculations to detennine the ART values for die South Texas Unit 1 intennediate shell plate, R1606-3 for 32 EFPY are shown in Table A-4.
l
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i igxamu.wpgr/0793 A-8 a . - , . -
TAllLE A-1 SOUTil TEXAS UNIT 1 REACTOR VESSEL TOUGIINESS TAllLE (UNIRRADIATED) l Material Description Cu Ni Initial (wt. %) (wt. %) RTm (*F) (a)
Closure llead Flange (b) -- -- 0 Vessel Flange (b) -- .. -10 Intermediate Shell Plate, R1606-1 0.(4 0.63 10 Intennediate Shell Plate, R1606-2 0.l4 0.61 0 Intennediate Shell Plate, R1606-3 0.05 0.62 10 Lower Shell Plate, R1622-1 0.05 0.61 -30 Lower Shell Plate, R1622-2 0.07 0.64 -30 Lower Shell Plate, R1622-3 0.05 0.66 -30 Inter. Shell Longitudinal Weld at 0" Azimuth 0.03 0.06 -50 Inter. Shell Longitudinal Weld at 1200 Arimuth 0.03 0.06 -50 Inter. Shell Longitudinal Weld at 240* Azimuth 0.03 0.06 -50 Lower Shell Longitudinal Weld at 90 Azimuth 0.03 0.06 -50 Lower Shell Longitudinal Welds at 210* and 330 0.03 0.06 -50 Atimuths Inter. Shell to Lower Shell Circumferential Weld 0.03 0.06 -70 (a) Initial RTm values were estimated per U.S. NRC Standard Review Plan ir2i The initial RTm values for the plates and welds are measured values.
(b) These values are used for considering flange requirements for the heatup/cooldown l
eurves^*
l l
l Igxetens.wp'070793 A-9 l
f-TABLE A-2 SOUTII TEXAS UNIT 2 REACTOR VESSEL TOUGIINESS TABLE (UNIRRADIATED)
Material Description Cu Ni Initial (wt. %) (wt. %) RTwir (*F) (a)
Closure Head Flange (b) -- --
-50 Vessel Flange (b) -- --
-10 Intermediate Shell Plate. R2507-1 0.04 0.65 -10 Interrnediate Shell Plate, R2507-2 0.05 0.64 -10 Intennediate Shell Plate. R2507-3 0.05 0.61 -40 Lower Shell Plate, R3022-1 0.03 0.63 -30 Lower Shell Plate, R3022-2 0.(M 0.61 40 Lower She!! Plate, R3022-3 0.04 0.60 -40 Inter. Shell Longitudinal Weld at 0* Azimuth 0.03 0.17 -70 Inter, Shell Longitudinal Weld at 120* Azimuth 0.03 0.17 -70 Inter. Shell Longitudinal Weld at 240 Azimuth 0.03 0.17 -70 Lower Shell Longitudinal Weld at 90* A7imuth 0.01 0.15 -70 Lower Shell Longitudinal Welds at 210* and 330 0.01 0.15 -70 l Azimuths ,
Inter. Shell to Lower Shell Circumferential Weld 0.01 0.15 -70 (a) Inidal RTunt values were estimated per U.S. NRC Standwd Review Plan ^23 l The initial RT Nm values for the plates and welds are measured values.
(h) These values are used for considering flange n:quirements for the heatup/cooldown curvesl ^.
spaansupv70793 A-10
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l TAllLE A 3
SUMMARY
OF ADJUSTED REFERENCE TEN 1PERATURES (ART's)
AT 1/4-T and 3/4 T LOCATIONS FOR 32 EFPY FOR SOUTil TEXAS UNITS 1 AND 2 South Texas Unit 1 South Texas Unit 2 Material Description 1/4-T 3/4 T Material Description 1/4-T 3/4-T Intermediate Shell Plate, 70 55 Intermediate Shell Plate, 50 35 R I606-1 R2507-1 ,
Intennediate Shell Plate, 60 45 Intermediate Shell Plate, 60 43 R I606-2 R2507-2 Intermediate Shell Plate, 80* 64* Intermediate Shell Plate. 30 13 R 1606-3 R2507-3 Lower Shell Plate, R1622- 41 27 Lower Shell Plate, R3022- 18 7 1 1 Lower Shell Plate, R1622- 57 44 Lower Shell Plate, R3022- 23 8 ,
2 2 Lower Shell Plate, R1622- 41 27 Lower Shell Plate, R3022- 23 8 3 3 Inter. Shell Longitudinal 1 -13 Inter. Shell Longitudinal -4 -23 Weld at 0 Azimuth Weld at 0 Azimuth Inter, Shell Longitudinal 3 -11 Inter. Shell Longitudinal -1 -20 Weld at 120 Azimuth Weld at 120 Azimuth Inter. Shell Longitudinal 2 -13 Inter. Shell lamgitudinal -3 -22 Weld at 240 Azimuth Weld at 240* Azimuth Lower Shell Longitudinal 1 -13 Lower Shell Longitudinal -30 -41 Weld at 9(P Azimuth Weld at 9(P Azimuth Lower Shell Longitudinal 8 -6 Lower Shell Longitudinal -24 -36 Welds at 210 and 330 Welds at 210 and 330 Azimuths A7imuths Inter. Shell to Lower Shell -12 -26 Inter. Shell to Lower Shell -24 -36 Circumferenti:il Weld Circumferential Weld
- These values were used in the development of the heatup and cooldown limit curves.
iricam+pario792 A-11 e
-l I
TAlli,E A-4 CALCULATION OF ADJUSTED REFERENCE TEMPERATURES AT 32 EFPY FOR Tile LIMITING REACTOR VESSEL, MATERIAL FOR SOUTII TEXAS UNITS 1 AND 2 -
SOUTIl TEXAS UNIT I INTERMEDIATE SIIELL PLATE, R1606-3 ,
Parameter 1/4-T 3/4 T Chemistry Factor, CF ( F) 31 31 Fluence, f (10" n/cm2 ) (a) 1.728 0.6134 Fluence Factor, ff 1.150 0.863 ARTmy = CF x f f ( F) 36 27 luitial RTmg , I ( F) 10 10 Margin, M ( F) (b) 34 27 Regulatory Guide 1.99, Revision 2 Adjusted Reference Temperature, ART ART = 1 + ARTmg +M 80 64 Notes (a) Fluence, f, is based upon the surface fluence (10" n/cm2 , E > 1.0 MeV) = 2.90 at 32 EFPY.
The South Texas Units 1 and 2 reactor vessel wall thickness is 8.63 inches at the beltline region.
(b) Margin is calculated as, M = 2 [ c,2 4 g6 2)<u The standard deviation for the initial RTmn margin term, o,, is assumed to be O'F since the initial RTmn is a measured value. The standard deviation for ARTmy term, c ,3 is 17*F for the plate, except that c3 need not exceed 0.5 times the mean value of ARTmn. o3 is 8.5'F for the plate (half the value) when surveillance data is used.
l gumsypnmtm A-12
1 MATERIAL PROPERTY BASIS LIMITING MATERIAL: South Texas Unit 1 Intennediate Shell Plate. R1606-3 LIMITING ART AT 32 EFPY: 1/4-T, 80*F 3/4-T, 64'F 2500 , , i . .
T r t i. _
! 'I 2250 ,
f
.___ ii i ii i f !
2000 L. ,-
UNACCEFTABLE __,___f +
l
_-OPERATION f
'T m
g i i <
c f
- i G 1750 i 4g/
k i i w LJ tr 1500 ' f-i 4--
D if w
l i i +
w i i y1250 '
l l l
/ j j
- a. l ACCEPTABLE o i FH/--~OPERAT1oN w
1000 i /---- i ; -
< il i n 52 y- r -
f.
o 750 I
5 ~t1- ,
l, ii iI! i! +
500 1.UEANP i T
{' dcoowoWN RATE
' O DEG F/HR %
250 -F -
t -
ii i l Ft L i ri. ;
t___ p! !
4 I 0b ,
T,_tN, i l
l t+ ,
i 0 50 100 150 200 250 300 350 400 450 500 INDICATED TEMPERATURE (DEG. F)
Figure A-1. South Texas Units 1 and 2 Reactor Coolant System Steady State Heatup/Cooldown
. Limitations Oleatup/Cooldown rate of 0 F/hr) Applicable for the first 32 EFPY (without margins for instrumentation enors).
ignmwwwom A-13 Y
4 l
A-6. REFERENCES j
[ Al] Regulatory Guide 1.99, Revision 2, " Radiation Embrittlement of Reactor Vessel Materials", U.S. Nuclear Regulatory Commission, May,1988. ;
i (A2] " Fracture Toughness Requirements", Branch Technical Position MTEB_5-2, Chapter -
5.3.2 in Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants, LWR Edition, NUREG-0800,1981.
[A3] ASME Boiler and Pressure Vessel Code, Section Ill, Division 1 - Appendixes, " Rules for Constmetion of Nuclear Power Plant Components, Appendix G. Protection Against Nonductile Failure", pp. 558-563, 1986 Edition, American Society of Mechanical Engineers, New York,1986.
[A4j Code of Federal Regulations,10CFR50, Appendix G " Fracture Toughness Requirements". U.S. Nuclear Regulatory Commission, Washington, D.C., Federal Register, Vol. 48 No.104, May 27,1983,
[A5] WCAP-12629 " Analysis of Capsule U from the Houston Lighting and Power Company South Texas Unit i Reactor Vessel Radiation Surveillance Program", E. Terek, et al.,
August 1990.
IA6] WCAP-13182," Analysis of Capsule V from the Houston Lighting and Power Company South Texas Unit 2 Reactor Vessel Radiation Surveillance Program", J. M. Chicots, et.
al., February 1992.
igcam.wnwom A-14
f ATTACHMENT Al DATA POINTS FOR l-lEATUP AND COOLDOWN CURVES 1
INDICATED INDICATED INDICATED INDICATED TEMPERATURE PRESSURE TEMPERATURE PRESSURE (L)EG. F) (PSIG) (DEG. F) (PSIG)
/
85 621.(X) 160 1130.30 ~ ;
90 621.00 165 1180.50 95 621.00 170 1234.44 ;
100 621.00 175 1292.33 105 621.00 180 1354.34-110 621.00 185 1420.86 115 621.00 190 1492.38 120 621.00 195 1569.00 120.1 835.50 200 1650.86 125 863.80 205 1739.13 130 894.11 210 1833.39 135 926.90 215 1933.95 140 961.99 220 2012.19 145 999.67 225 2157.74 150 1040.12 230 2281.16 155 1083.59 235 2412.68 u
incam.wplo70793 A-15
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