ML19318B697
| ML19318B697 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 06/23/1980 |
| From: | Naughton W COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8006270329 | |
| Download: ML19318B697 (9) | |
Text
. _.
Fs Commonwealth Edison -
[C
) One First National Pl"28, Chicigo. Ilhnois t
7 Address R: ply to: Post Office Box 767
\\
/
Chicago, Illinois 60690 June 23, 1980 Mr. Harold R. Denton, Director Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Zion Station Units 1 and 2 Response to Questions on Adequacy of Station Electric Distribution System Voltages NRC Docket Nos. 50-295 and 50-304 Reference (a):
May 2, 1980 letter from S. A.
Varga to D. L. Peoples Oear Mr. Denton:
Reference (a) requested Commonwealth Edison Company to provide additional information concerning the adequacy of station 1
electric distribution system voltages at its Zion Station. to this letter contains the requested information for Zion Station only. is a list of the previous referenced material.
Please address any questions that you might have concerning this matter to this office.
One (1) signed original and thirty-nine (39) copies of this transmittal are provided for your use.
Very truly yours, William F. Naught Nuclear Licensing Administrator i
Pressurized Water Reactors Attachments 4724A 8006270
NRC Docket Nos. 50-295 50-304 ENCLOSURE 1 Commonwealth Edison Company's response to the questions in the enclosure of Reference (a) concerning. adequacy of station electric distribution system voltages follows.
(See Enclosure 2 for appropriate references).
1.
Question The CECO. summary attachmenta (last paragraph) concludes that the computer program results need not be compared to test results for Dresden 1.
While the Zion program and input parameters were verified by test, it is not known that the input parameters for Dresden 1 (or other units) can be verified by test.
CECO. should verify the program, input variables, and constants used for the Dresden and Quad Cities analyses per the requirements of reference b, page 2, paragraph 3.
Response
This question does not apply to Zion Station because the Zion program and input parameters were verified by test.
The test results were provided in a letter from R. F. Janecek to W.
Gammill dated December 14, 1979.
(See Reference h.)
2.
Question Were the grid voltage valuas, 34.8 to 36.3 kV (item II, page 1)c, 132 to 142 kV (item II, page 1)e, 344 to 362 kV (item II, page 1)e, 333 to 354 kV (item II, page 1)f, and 343 to 354 kV (item II, page 1)9 determined per NRC guideline 67 If not, describe how they were obtained.
Response
The minimum expected grid. voltage of 343 kV at Zion Station was determined per NRC guideline 6.
Load flow studies show that this voltage could occur at Zion Station if both Zion generators are out of service at the time of system peak load.
3.
Question Supply the calculated voltages for all low voltage AC (less than 480 V) class lE buses for each analyzed case.
Do these systems supply any instruments and control circuits as required by GDC 137 If so, is all equipment capable of sustaining the analyzed voltages (blowing fuses, overheating, etc.)?
Is the connected equipment qualified by the manufacturers to withstand the
. expected voltages without affecting their ability to perform the required function?
Response
The instruments and control circuits as required by GDC-13 at Zion Station are powered by instrument buses normally supplied by inverters with voltage regulators.
4.
Question Figure 3c,e,f,g shows the lowest bus voltage when starting the largest non-class 1E load for respective plants.
Did this motor start when all the other loads were running?
Give the effect of starting this load on all class lE buses and loads per NRC D
guideline 3.
What are the bus and load voltages when starting the largest 480 V class 1E load when all other class 1E loads are running?
Response
The lowest bus voltage when starting the largest non-Class lE load was calculated when all other loads were running.
The motor would start under these conditions.
Attachments 1, 2 and 3 indicate the bus and load voltages at different buses (including Class lE es) when the largest load on the bus is started.
The attachme; represent different operating conditions. shows the voltages when the SAT of a unit carries the shutdown and accident loads of its own unit. shows the voltages for the same operating condition of the SAT as Attachment 1, except with the corrective measures proposed for Zion Station implemented.
The corrective measures consist of load shedding two Condensate Booster Pumps and one Circulating Water Pump as proposed in a letter to W.
Gammill from R.
F. Janecek dated December 14, 1979. indicates the voltages wnen the ESF bus of one unit is operated from the second offsite power supply.
The above Attachments a'.so indicate the bus and load voltages when the largest load on the 480 V Class lE bus is started with all other Class 1E loads running.
. 5.
Question Define how the acronyms SAT and RAT are used.
It appears, from references e, f, and g, that they might be used interchangeably.
The summary refers to SAT, while the detail review and figures refer to RAT on all units except Dresden 1.
Response
The acronyms SAT (System Auxiliary Transformer) and RAT (Reserve Auxiliary Transformer) may be used interchangeably.
The transformers connected directly to the transmission syste a and supplying power for the station auxiliaries had formerly been called Reserve Auxiliary Transformers.
These transformers now are used to supply power during normal operation, so they are now referred to as System Auxiliary Transformers.
6.
Question Is it possible that the unit's UAT can supply the class 1E load group while the main generator is disconnected?
If nothing I
prohibits such a connection to the offsite grid, this analysis should be performed per NRC guideline b.
Response
The unit auxiliary transformer (UAT) is directly connected to the generator bus.
In the event of a unit trip, the UAT is not available to supply auxiliary power to the station.
Only if the generator bus connection is unbolted and physically removed is it possible to disconnect the generator and energize the unit auxiliary transformer from the grid system to supply unit auxiliary power.
7.
Question Each SAT is capable of supplying its own unit's auxiliary load andtheegergencyloadoftheotherunit(seethe e
summary,,g).
NRC guideline 2 requires the voltage study for the largest, load demand including when one unit is in LOCA and the other unit is in safe shutdown.
The intertie be 24-1and34-1(Dresden)e,14-1and24-1(QuadCities)pweenbuses and a similar arrangement for Zion (bus numbers are unreadable in the report)9 demand this voltage analysis.
Response
l NRC guideline 2 required that an analysis be performed for (1) an accident in the unit being analyzed and simultaneous shutdown i
of all other units at that station or (2) an anticipated transient
t
. in the unit being analyzed (e.g., unit trip) and simultaneous shutdown of all other units at that station, whichever presents the largest load demand situation.
This guideline was followed in making the voltage analysis.
The loads when one unit is in LOCA and the other is in safe shutdown are less than the case studied in which one of the safety-related buses of one unit is fed from the opposite unit SAT while carrying its normal operating load.
CECO.'s understanding of Question #7 is that, additional voltage calculations are now required for minimum and maximum expected grid voltages for Limiting Conditions of Operation when one SAT
+
is out of service.
An analysis will be performed for the SAT of one unit out of service and one of its safety-related buses being supplied from the other unit SAT while also furnishing normal shutdown power (e.g. unit trip).
This analysis is expected to be completed by July 10, 1980.
4724A r
210N UNIT 1 TOLTA05 PROFILE FOR TAR 1055 MOTot STARTING COIC1710iG v1TNouf recrosto ComarCTIVs Maasens (AUTO TRIP OF 2 COND. BeOST l'
RUMPS AND 1 CibC. WTR. PU W )
l' Min. SCC = 11830 MTA l
Min. Volt = 343 kV 34s kV Sume m Starting Starting Starttaa Starting S att Startig Startin8 Starting e
Largest Largest Largest largest STSTDI AUITLIARY TRANSF0WEER Stor 9 Motor 9 Mocat 9 Motor t Condittee 345-4.16-4.16-4.16 kT Coedition no (SAT $ -2 E Tap or 336.375 kT) 480V E55 480V Ess 4160r Busr.160V But C
4160Vaus 4160V Set 480V Ess 480V ESS
- 9.461 Sue 139 Sus 138 144 + 141142 + 141
- EK ur 9
33/44/55 MTA 142 + 143 144 + 145 Bus 134 aus 139 1
z,, - 7.65: z,3 - 1.55: 15 200 PP 250 HP 6000 EP M)00 NF Voltage 2 = 7.652 zgy =19.281 MN 6M W 2M W 200 p Aus.t!ds Fire Pu RxCool P RmCool F 9g Voltage {
RxCool F RmCool P FirePump Auz. Bldg.
Wat Fan
...M d u..
T Vent Fan r%
r S
X Z
T Sus Volt 3183 3829 3817 3330 l
W W
W 3810 4 kT Buses 142 & 143 3915 3915 3271 3913 Bue Volt No Load 2 of 4000V 79.1 95.2 94.9 95.2 Ess ausee 147 & les 8"y' I
1895 3895 3251 3893 Equip. Volt l
97.4 97.4 81.3 97.3 2 of 40009 20 + j8.5 MVA 24 + jl0 A Unit Sub. 138 Unit Sub. 139 w
JJ x = 11.4% e 1500 kTA a y I = 11.4% 01500 kTA P 4160-480V (Set 9 rv m 4160-480V 4055V Tap)
Bus Tott 323 413 369 412 480V Bus 138 Equip. Volt 309 398 355 398 l
393 430 351 430 Bue volt 1243 + j771 kVA I of 460V 67.1 86.5 77.2 86.5 379 416 337 416 Equip. Volt 6bOV Suo 119 82.4 90.4 73.3 90.4 1 of 460V g
g y Unit Sub. 132 (Non-ESF) 707 + j438 kVA ry % 2 = 11.41 0 1500 kVA l
4160-480V (Set 0 4055T Tap)
Bus Tott 327 415 413 415 480V Bus 132 Equip. Volt 313 401 399 401
.2 8.2 l
1174 + jf27 g kVA f
AU11LIART SYS1EM PERF00MANCE SAT CARRIES SHUTDOWN &
ACCIDENT LOAD 1
o IION UNIT 1 ATTAcegyr 3 0
VOLTACE PROFILE FOR VARIOUS MOTOR STARTiuG CONDITIONS WITE PROPO$tD CORRECTIVE MEASURE APPLIED (2 COND. 300ST PL*MPS AND 1 CIRC. WTE. FWW AUTO TRIPPED) o Mio. SCC = 11830 MVA Mio. Volt = 343 kV g
345 kV Systes Starties Starttea Starting Starting Larsest largest Largest Largest SYSTE't AUIILIART TRANSF0WER Starting Startime Starting Starting Motor 3 Motor 9 Motor f Motor e Condition 345-4.16-4.16-&.16 kV tar 8est Larseet Larseet urge.c l
(SAT @ -25% Tap or 136.375 kV)
Condition Motor #
hter f hter #
Motor #
&BOV ESS 480V 1554160V h s 4160V Bus
+
h = b = 9.462 9
33/44/55 MVA
-<p.
4160Vaus 4160Vaus 480V ESS 4807 Ess Bus 139 Bus 13R 144 + 145 142 + 143 Z = 7.65% Zgg = 7.552 15 142 + 141 144 + 145 nue 13e 3 33g g
HZ "YA 200 Mr 250 HP 6000 BP 6000 HP Volt'8*
L
- 7.652 bT=19.282 000 WP 6000 RP 250 at 200 ur Aax.Bldr Fire Pu hCool P 8xCool P
<t s.,,
voltage l TE Vent Fan
-,,.g y
RmCool F RaCool F FirePump Auz. Bldg Ve.t r i
,r '
, e ~T I
I 4 kV Buses a kV Sus 141 1
Bus Volt 3244 3889 3884 3889 144 & 145 4 kV sue e 142 6 143 3956 3956 3312 3956 Bus Volt ESF Bus 149 ESS Suses 147 6 148 Equis. Volt 3224 3369 3864 3869 3936 3936 3292 3936 Equip. Volt 2 of 4000V 80.6 96.7 96.6 96.7 98.4 98.4 82.3 98.4 2 of 4000V f g
18 + J7.6 20 + 39.2 l
MVA MVA Unit Sub. 138 Unit sub. 139 JJ I = 11.4% 01500 kVA I = 11.4% 01500 kVA M 4160-480V (Set 6 i
m m 4160-480V 4055V Tap) 332 420 374 420
?-
Bus Volt 480V Bus 138 Equip. Volt 318 406 360 406 435 355 435 Bus volt 88*3 I8 3 88 3 398 isov Bus 139 384 421 341 421 Equip. Volt Unit sub. 132 m a-ESP) 83*5 91*5 74*1 91*5
% of 460V j
LA JJ 707 + je38 kVA m% I = 11.4% @ 1500 kVA i
4160-480V (Set 9 4055V Tap) 480V Bus 132 Bue Volt 334 422 423 423 1174+j727kVAf E "I. Volt 322 409 409 40g l
9 P I of 460V 70.0 33.1 88.1 88.9 i.
AUITLIARY SYSTEM PERFOItMANCE 4 -
SAT CARRIES SHUTDOWN &
ACCIDENT LOAD p
e ATT40ptRirF 3 ZION UNIT 1 VOLTACE P90 FILE FOR VARIOUS 98&f05 ST4RTING CONDTTIONS Min. SCC = 11830 HTA e
Min. Volt = 343 kV 345 kV System t
5 tarting Beattings gH mg.
farting x5-4.16-4.1.IARY TRANSFONGR
";;;; 2;;;;
SYSTDI AUITL Largest urgest
-A.16 kV
<oto, f rot.,f Co.u uo.
m,uo, 480V ESS 4160t Bus e
IT f
($ET f 336375V (-2 I) Tap) 4160V Bus 480V Ess sus 138 241 2 = 7.653 E = 7.551 ' 15 33/44/55 MVA N
B2 gg 241 Bus 138
- A
=19.281 i
ZYZ= 7.653 Zg p
'II*I*
11M W 2M W I
FirePump SCFWP Voltage l
SCFWP FirePump re" % mm mm 1
Z Y
.L 5
Bus 144 tua 14 2 to+j3.5MVAf 10 + j3.6 W A<t i
3967 2948 Bus volt rss Eue l
4 kV sus 241 Bue Volt 2960 3977 3947 2925 Equip. Volt 148 9
aEquip. Volt 2940 3957
{25 98.7 73.2 1 of 4000V 6
I of 4000Y 73.5 98.9
- E'
{
g 2 W1od W e 10.1 + j4.6 MVA ADMINISTRATIVE PROCEDURE P90Elb1TS THE START!!IG OF TBE 11000 MP SCFWe WHEM THE 2 WINDING IS FEEDING TBE ESF 14AD OF THE OTHER UNIT, 11000 hp 4160-480V i
s4..u 1 = 11.41 0 1500 kVA FY"" (5ET f 4055Y Tap) t 384 299 Boa Volt 370 286 Equip. Volt 480V Bus 138 1243 + jf71 kVA AUXILIARY SYSTDs PERFORMANCE ESF BUS OPERATED F90M SLO 7ND OFFSITE $UPFLY t
t References a.
CECO. letter (Janecek) to NRC (Gammill), " Adequacy of Station Electric Distribution System Voltages," dated February 1, 1980 b.
NRC generic letter to all Power Reactor Licensees, " Adequacy of Station Electric Distribution System Voltage," dated August 8, 1979.
c.
" Adequacy of Station Electrical Distribution Systems Voltages, Dresden Unit 1," Sargent & Lundy Engineers report, attachment A to reference a.
d.
CECO. letter (Janecek) to NRC (Gammill), " Adequacy of Station Electric Distribution System Voltage," dated November 1, 1979, e.
" Adequacy of Station Electrical Distribution Systems Voltages,"
Dresden Units 2/3," Sargent & Lundy Engineers report, enclosure 1 of reference d.
f.
" Adequacy of Station Electrical Distribution Systems Voltages, Quad Cities," Sargent & Lundy Engineers report, enclosure 2 of reference d.
g.
" Adequacy of Station Electrical Distribution Systems Voltages, Zion," Sargent & Lundy Engineers report, enclosure 3 of reference d.
h.
CECO. letter (Janecek) to NRC (Gammill), " Adequacy of Station Electric Distribution System Voltages," dated December 14, 1979.
4724A