ML13333A471
| ML13333A471 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/18/1980 |
| From: | Haynes J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Harold Denton, Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8001220361 | |
| Download: ML13333A471 (3) | |
Text
Southern California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 January 18, 1980 Director of Nuclear Reactor Regulation Attention:
Mr. D. L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Loss of Offsite Power Events San Onofre Nuclear Generating Station Unit 1 Your letter of September 25, 1979, requested information concerning total and partial loss of offsite power events at San Onofre Nuclear Generating Station, Unit 1. Our letter of December 26, 1979, provided some of the available information and stated that SCE would review the operator's logs to determine whether any of the partial losses of offsite power resulted in oscillograph operation. The results of that review are contained in the enclosure to this letter, along with other salient points concerning the events. For events listed in our December 26, 1979 letter, but not listed in this enclosure, there was no record of oscillograph operation or other significant notation in the operator's log book.
If you have any questions, please let me know.
Very truly yours, J. G. Haynes Chief of Nuclear Engineering Enclosure A
8001L220 56
Enclosure TABLE 1 Salient Points of Partial Loss of Offsite Power Events San Onofre Unit 1
- 1) 4-2-68 12:17 PM - San Mateo* line tripped.
Station oscillograph initiated on 4 kV bus #1 low voltage. There is no record of minimum voltage or frequency.
- 2) 6-11-68 6:32 AM -
Chino line tripped at one end.
There is no record of the oscillograph operating, but the operator recorded a 500 volt drop on the generator recording voltmeter.
- 3) 1-6-69 1:54 PM -
Chino line tripped. There was also a carrier alarm on the Chino and Villa Park lines. The oscillograph was out of service for maintenance at the time. There is no record of minimum voltage or frequency.
- 4) 2-6-69 6:10 AM -
San Luis Rey line tripped due to wind storm.
Oscillograph initiated on 4 kV bus #1 low voltage.
Voltage dropped to about 2 kV. There is no record of bus frequency or duration of low voltage.
- 5) 2-24-69 11:30 AM -
SDG&E tripped the Capistrano line because a tower was falling over. At 10:52 PM, Villa Park and Chino lines tripped when a pole blew over.
(SDG&E records show the San Mateo line also tripped.)
Operator logged station frequency at 61.65 Hz. At 10:59 PM, the Chino line was re-established and station frequency returned to 60 Hz. There was no record of oscillograph initiation or bus voltage.
- 6) 8-22-69 9:57 PM -
San Luis Rey line tripped due to brush fire at Camp Pendleton. Operator logged "momentary upset of auxiliary voltage". There were no other records of voltage or frequency.
- 7) 6-22-71 7:52 AM -
Chino line tripped when a contractor shorted the line.
The turbine tripped on load dump anticipator and backup overspeed.
The reactor scrammed. There was no record of oscillograph operation, voltage or frequency.
- 8) 4-1-73 2:05 PM - Santiago line tripped due to incorrect relay operation.
Station oscillograph initiated; there is no record of voltage or frequency.
- 9) 8-6-73 1:47 PM -
San Luis Rey line tripped from unknown cause.
Oscillograph initiated; there is no record of voltage or frequency.
- 10) 8-15-73 10:23 PM -
Capistrano line tripped during hot wash.
Oscillograph was initiated when SDG&E/SCE tie line took a 40 MWe swing.
No record of voltage or frequency.
- 11) 8-16-73 12:25 PM -
San Mateo line tripped when a crane contacted the line. Oscillograph initiated; there is no record of voltage or frequency.
-2
- 12) 11-29-73 10:33 AM - Mission line tripped from trouble off system.
Oscillograph initiated and there was a 220 kV bus underfrequency alarm.
There is no other record of voltage or frequency. It was also noted that the underfrequency alarm circuit required repair following this event. It is not clear from the records if the alarm was spurious or not.
- 13) 2-23-74 8:32 AM -
Capistrano line tripped from unknown cause.
Oscillograph initiated; there is no record of voltage or frequency.
- 14) 11-7-74 9:05 AM -
San Mateo line tripped due to pot head failure. The oscillograph initiated; there is no record of voltage or frequency.
- 15) 2-15-75 5:34 AM -
Capistrano line tripped due to hardware failure. The oscillograph initiated; there is no record of voltage or frequency.
- 16) 8-12-75 3:43 PM -
Capistrano line tripped from unknown cause.
The oscillograph initiated; there is no record of voltage or frequency.
- 17) 1-21-76 4:17 AM -
Due to a brush fire, the San Mateo, Capistrano, Santiago and Chino lines tripped.
The turbine tripped on apparent over speed and the reactor scrammed.
The oscillograph initiated; there is no record of voltage of frequency.
- 18) 7-23-77 10:13 AM -
Capistrano line tripped due to lightning.
The operator noted that there was no change in load or frequency.
- 19) 3-8-78 3:13 PM -
Mission line tripped due to sustained three phase fault at SDG&E South Bay Plant switchyard.
Reactor scrammed on loss of flow in one reactor coolant loop.
There is no record of voltage or frequency at San Onofre.
- 20) 12-19-78 12:46 PM -
Chino line tripped due to lightning.
The oscillo graph initiated; there is no record of voltage or frequency.