ML17249A327
| ML17249A327 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 12/06/1979 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17249A328 | List: |
| References | |
| TASK-08-01.A, TASK-8-1.A, TASK-RR NUDOCS 7912120450 | |
| Download: ML17249A327 (6) | |
Text
REGULATORY ORMATION DISTRIBUTION SY M (RIDS)
ACCUS ION NBR: 7912120450 DOC ~ DATE: 79/12/06 NOTARIZED:
NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear PlantE Unit ii Rochester G
05000244 c AUTH BYNAME AUTHOR AFFILIATION HHITEEL,D~
Rochester Gas L Electric Corp.
RKCIP ~ NAME RKCIP IENT AFFILIATION ZIEMANNED ~ L ~
Operating Reactors Branch 2
SUBJECT:
Forwards "Design Analysis Adequacy of Station Electric Distribution Sys Voltages." Analysis determined that some operating conditions have potential to cause, spurious separations of safety buses from offsite power sourcesA%
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zzzsiuz ROCHESTER GAS AND ELECTRIC CORPORATION o
89 EAST AVENUE, ROCHESTER, N.Y. 14649 LEON D. WHITE. JR.
VICE PRESIDENT TELEPHONE AREA CODE TIE 546.2700 December 6,
1979 Director of Nuclear Regulation Attention:
Mr. Dennis L. Ziemann, Chief Operating Reactors Branch 52 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Adequacy of Station Electric Distribution Systems Voltages
Dear Mr. Ziemann:
In accordance with your letter, dated August 8, 1979 from William Gammill to All Power Reactor Licensees and with our letter dated October 8,
- 1979, RG&E has completed a load flow analysis which models the Ginna electrical distribution system.
This analysis was performed in accordance with the guidelines set forth in your August, 7, 1979 letter and a copy along with Attach-ment I is enclosed.
The objective of this study was to determine the resulting voltage drops due to normal plant operating condi-tions and also to determine any potential inconsistencies with General Design Criteria (GDC) 17.
The analyses has determined that, only a few operating condi-tions have the potential to cause spurious separations of safety buses from the offsite power source.
These conditions can be corrected by raising the minimum offsite voltage levels."
This will then maintain adequate inplant bus voltages.
The results of the analysis will be verified by a compre-hensive testing program.
The data generated by this program will be compared to the calculated values herewith and stored in the interactive load flow program.
In addition to the analysis, a detailed review of the electric power system was required to determine if there are any events or conditions which could result in the simultaneous loss of both required offsite sources.
It has been determined that the follow-ing types of failure will result in a simultaneous failure of both offsite sources:
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ROCHESTER GAS AND ELECTRIC CORP.
DATE December 6,
1979 To Mr. Dennis L. Ziemann, Chief
'Ii SHEET NO.
1.
The failure of the startup transformer (unit 012), or 2.
A bus fault on the 34.5 kV open bus, or 3.
A fault on either the nonsegregated phase bus ducts or the transformer 4 kV metal clad breakers, or 4.
The failure of number 6 transformer in the switchyard, circuit 767.is the normal source and when it, fails the safety buses are deenergized until either the diesel generators go into service or the operator manually places the 751 circuit into service, or 5.
An event that. causes both 115 kV bus sections at Station 13A to trip, if both bus sections remain out of service, station 204 is deenergized.
This results in the loss of both offsite sources until line switching can be accomplished and station 204 is reenergized from the remaining portion of the 115 kV system.
The single events listed above will cause the loss of both offsite sources, however they have a relatively low probability of occurrence.
Finally, once the offsite voltage levels are maintained at the recommended values contained in the analysis, no offsite conditions have the potential to violate GDC-17.
L. D. Whi e, Jr.
Enclosure
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