ML19320B230
| ML19320B230 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/25/1980 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Ferguson J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 8007100078 | |
| Download: ML19320B230 (5) | |
Text
.
O
,w jeg?'yY! Y
[i,e j
NUCLEAR REGULATORY COMMISSION h
C WASHINGTON, D. C. 20555 i
%, ' v...../
June 25, 1980 Occket No. 50-338 Mr. J. H. Ferguson Executive Vice President - Pcwer Virginia Electric and Power Company Post Office Box 25666 Richmond, Virginia 23261 Cear Mr. Ferguson:
We have reviewed your submittals of October 9,1979 and November 28, 1979 regarding the adequacy of station electric distribution system voltages at the North Anna Power Station, Unit No. 1.
Our review indicates that additional infornation as provided in the enclosure to this letter is required in order for us to complete our rev;ew.
1 We request that your response to the enclosure be submitted within 45 days receipt of this letter. Please inform us within seven days after receipt of this letter of your confirmation of our requested response date or the date you will be able to meet.
Sincerely.
a bMb Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
Request for Additional Information cc w/ enclosure:
See next page e
80071000N A
s.
Mr. J. H. Ferguson Virginia Electric and Power Conpany cc: Richard M. Foster, Esquire Mrs. June Allen 1230 A Pearl Street 412 Cwens Drive Denver, Colorado 80203 Huntsville, Alabama 35801 Michael W. Maupin, Esquire Mr. James Torson Hunton, Williams, Gay and Gibson 501 Leroy P. O. Box 1535 Socorro, New Mexico 87801 Richmond, Virginia 23212 Mrs. Margaret Dietrich Alderman Library Route 2, Box 568 Manuscripts Department Gordonsville, Virginia 22042 University of Virginia Charlottesville, Virginia 22901 Mr. James C. Dunstance State Corporation Connission Mr. Edward Kube Connonwealth of Virginia Board of Supervisors Blandon Building Louisa County Courthouse Richmond, Virginia 23209 P. O. Box 27 Louisa, Virginia 23093 U. S. Environmental Protection Agency Region III Office Ellyn R. We'ss, Tsquire ATTN: EIS COORDINATOR Sheldon, Ha-non, Roisman and Weiss Curtis Building 1725 I Street, N.W., Suite 506 6th and Walnut Streets Wast..ngton, D. C.
20006 Philadelphia, Pennsylvania 19106 Connonwealth of Virginia Director, Technical Assessment Division Council on the Environment Office of Radiation Programs (AW-459) 903 Ninth Street Office Building U. S. Environmental Protection Agency Richmond, Virginia 23129 Crystal Mall #2 Arlington, Virginia 20460 Mr. W. R. Cartwrignt, Station Manager P. O. Box 402 Mr. Paul W. Purdom Mineral, Virginia 23117 Environmental Studies Institute Drexel University Mr. Anthony Gambardella 32nd and Chestnut Streets Office of t.ie Attorney General Philadelphia, Pennsylvania 19104 11 South 12th Street - Room 308 Richmond, Virginia 23219 Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Connission Mr. Allan Tattersall Washington, D. C.
20555 Resident Inspector / North Anna c/o U.S. NRC P. O. Box 128 l
Spotsylvania, Virginia 22553 1
i
~
l' 9
l$
ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION REGARDING THE ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES NORTH AN.'LL UNIT 1 (DOCKET NO. 50-338)
Re ferenc e s s.
TEPCo letter, C. M. Stallings to Harold R. Denton, NRC, Serial No. 454/072878, Docket Nos. 50-338 and 50-339, September 12, 1978.
b.
VEPCo letter, Sam C. Brown, Jr., to James P. O'Reilly, NRC, Serial No. 403A, Docket No. 50-339, August 7,1979.
NRC generic letter to all Power Reactor Licenees, " Adequacy of Station c.
Electric Distribution System Voltages," August 8,1979.
d.
VEPCo letter, C. M. Stallings to Harold R. Denton, NRC, Serial No. 352A, Docket No. 50-338, " Adequacy of Station Electric Distribution System Voltages," August 16, 1979.
VEPCo letter, C. M. Stallings to Harold R. Denton, ERC, Serial e.
No. 673/080879, Docket Nos. 50-280, 50-281, 50-338, and 50-339,
" Adequacy of Station Electric Distribution System Voltages,"
October 9,1979.
f.
VEPCo letter, C. M. Stallings to Harold R. Denton, NRC, Serial No. 673A/080879, Docket Nos. 50-338 and 50-339, "GDC-17, Compliance Review Results," November 28, 1979.
g.
VIPCo letter, Sam C. Brown, Jr., to James P. O'Reilly, NRC, Serial No. 711/120/78, Docket No. 50-339, January 12, 1979.
Que stions 1.
Pages 1 and 2 of references b and d list pre-conditions that need to be met to assure that the worst-case loading assumed for the study is 1
MMM SO
not exceeded. The se limiting conditions of operation (LCO) should be included in the North Anna Technical Specifications.
2.
Page 1 of both reference b and d and item (1) of the attachment of reference a indicate that the voltage at the emergency buses must be b
maintained above 90% of r.ocer rated voltage. Enclosure A,d shows a plot of " minimum acceptable" voltage, which allows the 480 V emer-gency buses to be lower than 90% voltage. Resolve this discrepancy.
- 3.,d shows voltage levels below 90%. Justify continued c,peration of the emergency loads under these conditions. Enclo-sure A ' does not show the voltage levels for the 480 V class IE buses. Supp ly.
b 4.
The assumed minimum grid voltage per assumption A, page 2,d g,
508 kV.
The attachment of reference a indicates that 482 kV is pos-sible on the 500 kV grid. Per NRC guide.line 6*, the minimum expected grid voltage should be used in the analysis.
8 ade-5.
Does the 90% of 4160 V setpoint of Grid Degraded Protection quately protect 480 V and 120 V class 1E equipment? The enclosure in section 1.a3 indicates that VEPCo plans to operate motors down to "85% potential value." This cannot be allowed unless VIPCo can verify by manufacturer or test data that this will not be adverse to motor life.
6.
What are the voltages and duration of depressed voltage on all class 1E buses when starting and running a 7000-EP reactor coolant pump? Justi-fy continued operaton of the class lE loads for this duration and describe how spurious trips of the class IE buses and loads are pre-vented during this time peried. The intent of NRC quideline 3" was that, during the worst case (reactor trip) loading conditions, consid-erstion should be made for any possible start of a large r.on-safety load. The analysis would then show the resultant voltages on a.ll safety-related loads (buses) during the transient (start) and the steady state (running) conditions.
)
2
i.
I 7.
Paragraph 2 indicates that some modifications are required in the North Anna switchyard to meet the intent of reference e requirements regarding CDC 17.
When will these modifications be complete and documented?
8.
Unit one-line diagrams, enclosure C '
indicate that it is pos sible for all class lE buses to be supplied power from reserve transformer C.
It is not evident that references b and d have analyzed for this pos-sible loading. Per guideline 1, perform analysis " assuming the power source to the safety buses is... other available connections to the offsite network one by one... ".
9.
Guideline 11*, which asks for a deter =ination of the maximum voltage expected at each safety load (and starting circuit), has not been supplied by any of the VEPCo references.
VEPCo should supply this analysis; they should identify and correct any overvoltage conditions.
10.
As required by MRC guideline 9, VEPCo should provide analysis and comparison of terminal voltages en all class 1E loads (4160 V, 480 V, and lower voltage buses and loads) for the worst case starting voltage and steady state running voltages. Enclosures A and B,d do not include these values.
11.
Will the controls and instruments (low voltage circuits) perform their functions as required under the voltages calculated in Question 10 without overheating, blowing fuses, ete?
l 3
l l
i
.