ML19323G945
| ML19323G945 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 06/05/1980 |
| From: | Naughton W COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8006090305 | |
| Download: ML19323G945 (2) | |
Text
_ _ _ _ _ _.
/rhs Commonwealth Edison O
2
)
/
oni First National Plaza. Chicago. Ilknois (O
7 Addrtss R: ply to: Post Office Box 767
/ Chicago, Illinois 60690 x
June 5, 1980 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Zion Station Units 1 and 2 Response to Loss of Of fsite Power Survey NRC Docket Nos. 50-295 and 50-304 Reference (a):
May 6, 1980, letter from S. A.
Varga to D. L. Peoples
Dear Mr. Denton:
Reference (a) requested Commonwealth Edison to provide a history of experienced total and partial power outages and attendant degraded voltage or frequency conditions of the grid that have occurred at Zion Station.
Commonwealth Edison has made a review of the operating experience at lion Station regarding loss of. offsite power.
To date, there have been g events resulting in complete loss of offsite power.
However, there has been one event resulting in a partial loss of offsite power which was reported to the NRC in Reportable Occurrence Report Number 50-295/79-016. to this letter contains the information related to this partial loss of offsite power as requested in the enclosure to Reference (a).
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. Naughtom Nuclear Licensing Administrator Pressurized Water Reactors Enclosure 8006090 M 6 m sa
NRC Docket Nos. 50-275 50-304 ATTACHMENT 1 Commonwealth Edison response to Loss of Of fsite Power Survey.
A.
For losses of offsite power where less than all of fsite power 4
was lost:
1.
How many circuits to the offsite network are normally available and how many were lost during the event?
Two circuits are normally available.
One was lost during the event.
2.
What was the cause of the event?
The cause of the event was personnel error.
Equipment was switched out of service in violation of Technical Specifications.
3.
Why did the other lines not fail when some did Iail?
There were no line failures.
4.
Was any voltage increase or decrease experienced just prior
~
to or during the outage?
If so, please give details, voltages reached, effects, etc.
No voltage increase or decrease was experienced as part of this event.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give detail.,, lowest frequency reached, decay, rate, ef fects on equipment operation, etc.
No frequency delay was experienced.
6.
How long was power unavailable from the circuit?
Power was unavailable for 45 minutes.
7.
Date of the event.
March 12,.1979.
B.
For losses of all offsite power:
To date, there have been no events resulting in complete loss of of fsite power at Zion Station