ML19305B341
| ML19305B341 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/10/1980 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8003190547 | |
| Download: ML19305B341 (9) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 SHIELDS L. D ALT 8 TOFF vsCs enroscant ELECTmc PnODUCTION Harch 10, 1980 Re: Docket Nos. 50-277 50-278 Mr.
T.
A.
Ippolito, Chief Operating Reactors Branch #3 Division of Oper' acing Reactors U.S.
Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Ippolito:
This letter is in response to your letter to E.
G.
Bauer, J r.., (PECo.) dated December 13, 1979, c'oncerning the loss of offsite power to Peach Bottom Units 2 and 3.
The items of concern and our responses are treated sequentially for each event.
A.
For_ losses of offsite power where less than all offsite power was lost:
Event I 1.
How many circuits to the offsite network are normally available and how many were lost during the event?
Res,ponse Two circuits' are available and one was lost.
2.
What was the cause of the event?
. Response No. 220-08 line which supplies auxiliary power tripped at Peach Bottom when the line relay panel was bumped by stacion personnel.
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i
Mr.
T.
A.
Ippolito Page 2 3.
Why.did the other lines not fail when some did fail?
Response
This item is not applicable because only one relay was accidently bumped by station personnel.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
No voltage increase or decrease was experienced just prior to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outagg]__If so,.please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
No frequency decay was experienced just prior to or during the outage.
6.
How long was power unavailable.from the circuit?
Response
12 minutes.
7.
Date of Event.
Response
April 19, 1974.
Event II 1.
How many circuits to the offsite network are normally available and how many were lost during the event?
Response
Two circuits are available and one was lost.
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M r '.
T. A.
Ippolito Page 3 2.
What was the cause of the event?
Response
The Peach Bottom No. 1 500/230kv transformer which supplies auxiliary power via a tertiary winding trippeu on operation of the sudden pressure relay.
This relay incorrectly operated for a fault external.to the transformer.
The tripping occurred when No. 220-06 and 220-07 lines (Peach Bottom-Muddy Run) were struck by ligh tning.
3.
Why did the other lines not fail when some did fail?
Response
This feed is independent of the other auxiliary feed.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
The information concerning the voltage increase or decrease just prior to or during the outage is not available.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
The information concerning any frequency decay experienced just prior to or during the outage is not available.
6.
How lonr, was power unavailable from the circuit?
Response-9 hours snd 25 minutes.
7.
Date of Event.
Response
July 11, 1976.
4
!!r. T.
A.
Ippolito Page 4 Event III 1.
How many circuits to the offsite network are normally-available and how many were lost during the event?
Response
Two circuits are available and one was lost.
2.
What was the cause of the event?
Response
No. 220-08 line which supplies auxiliary power, tripped due to a current transformer failure at Graceton (Baltimore Gas & Electric).
4 3.
Why did the other lines not fail when some did fail?
Response
This feed is independent of the other auxiliary feed.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
No voltage increase or decrease was experienced just prior to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
No frequency decay was experienced just prior to or during the outage.
6.
How long was power unavailable from the circuit?
Response
8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 25 minutes.
7.
Date-of Event.
Response
June 7, 1977.
Mr.
T.
A.
Ippolito Page 5
' Event IV 1.
Ilo w many circuits to the offsite network are normally available and how many were lost during the event?
Response
Two circuits are available and one circuit was lost.
2.
What was the cause of the event?
Response
No. 220-08 line which supplies auxiliary power, tripped when a tree contacted the
'A' phase conductor.
3.
Why did the other lines not fail when some did fail?
Response
This feed is independent of the other auxiliary feed.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
No voltage increase or decrease was experienced just prior to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
No frequency decay was experienced just prior to or during the outage.
6.
how long was power unavailable from the circuit?
Response
7 minutes.
7.
Date of Event.
Response
July 5, 1977, 8:20 PM.
-ww
Mr.
T.
A.
Ippolito Page 6 Event V 1.
How many circuits to the offsite network are normally
- vailable and how many were lost during the event?
Response
Two circuits are available and one was lost.
2.
What was the cause of the er.nt?
Response
No. 220-08 line which supplies auxiliary power, tripped when a tree contacted the
'A' phase conductor.
This is the same tree as in Event III.
3.
Why did the other lines not fail when some did fail?
Response
This feed is independent of the other auxiliary feed.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, a f f ec t s_,
etc.
Response
No voltage increase or decrease was experienced just prior to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
No frequency decay was experienced just prior to or during the outage.
6.
How long was power unavailable from the circuit?
Response
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 37 minutes.
7.
Date of Event.
Response
July 5, 1977, 8:30 PH.
1
Mr.
T.
A.
Ippolito Page 7 Event VI 1.
How many circuits to the offsite net work are normally available and how many were lost during the event?
Response
Two circuits are available and one circuit was off.
2.
What was the cause of the event?
Response
A defective differential relay was installed on the Pecch Bottom No. 1 500/230kv transformer causing the transformer to trip.
A tertiary winding of this transformer supplies station auxiliary power.
3.
Why did the other lines not fail uhen some did fail?
Response
This item is not applicable because the defective relay was only installed on Peach Botton No. 1 500/230kV transformer.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
No voltage increase or decrease was experienced just prior to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
Response
No frequency decay was experienced just prior to or during the outage.
6.
How long was power unavailable from the circuit?
Response
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 5 minutes 7.
Date of Event.
V m
Mr.
T. A.
Ippolito Page S Re s go n_s,e December 20, 1977.
Event VII 1.
How~many circuits to the offsite network are normally available and how many were lost during tne event?
Response
Two circuits are normally available and one was lost.
2.
Wnat was the cause of the event?
0 :
Response
The Peach Botton North Substation No. 1 transformer 500/230kv which supplies station auxiliary power via a tertiary winding tripped due to high temperature.
The transformer coolers were found to be turned off resulting in high temperature operation.
The " loss of cooler" alarm-was found to be inoperative due to a blown fuse.
3.
Why did the otner lines not fail when s o rae uid fail?
Resgonse The other station auxiliary supply is f rom an-independent source.
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
Response
No voltage increase or decrease was experienced just prior'to or during the outage.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment op-stion, etc.
Re,pnse No frequency decay was experienced just prior to or during the outage.
6.
How long was power unavailable from the circuit?
- r 4
Mr. T.
A.
Ippolito.
Page 9
Response
16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 50 minutes.
7.
Date of Event.
Response
March 5, 1930 3.
For losses of all offsite power:
R_esponse There has been no loss of all offsite power at Peach Bottom.
C.
Were there any other loss of offsite power events other than we have listed?
If so, please give details of each event.
Re_a_p o n s e The partial losses of offsite power described herein are the only events experienced at Peach Bottom.
Should you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours,
/
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