ML20090D721
| ML20090D721 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/31/1975 |
| From: | Carroll J JERSEY CENTRAL POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| AO-50-219-75-09, AO-50-219-75-9, NUDOCS 8303020306 | |
| Download: ML20090D721 (4) | |
Text
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J taics P. O' Rei J ly To:
Directorate of Regulatory Operations i
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Region I s
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631 Park Avenue l
1940G King of Prussic, Pennsylvania i
Jersey Central Po'.:er G Light Company Docket #5'0-219 From:
Oyster Crcok Nuclear Gencrr. ting Stction OS731 Forhed River, New Jersey W'$
Ab' normal Occurrence Report No. 50-219/.M/j_
Subj ect :
The fc11cch n i, a preliulr.try report being -ubr.itted in complicnca with the Technical Specifications paragraph 6.6.2.
Preliminary Approval:
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3/31/75
[J.T.Cario11.J[
Date Mr. A. Giar.busso cc:
o p'o?lf 8303020306
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'00PY SENT REGION 1_
Initiai Telc' hone
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Pepxt Date:
3/30/r/
Od % ence:
3/29/75 e
initiniWritten Tite of Report Date:
3/31/75 0ccurrence:
1940 L
OYS3ER CEEK l'UCLEAR GEERATIl10 STATION K)RKED RIVER, IEl JERSEY 08731 Abnormal Occurrence Report I!o. 50-219/75/9 i
IDEUf1FICATION Electrical fault en 10 bus and subsequent trip of "1C" OF OCCURT!!CE:
breaker.
This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15B.
CONDITIO:!S PRIOR Steady State Power Routine Shutdown TO OCCUTRG!CE:
Hot Standby Doeration Cold Shutdo.:n Load Changes During X Refueldrg Shutdown Routine Power Operatien Routine Startup Other (Specify)
Operation Uhe reactor modo switch was in the REFUEL position uith reactor I
coblant terpcrature approximately 1500 F.
1ESCRIPTIO:': OF At 1940 on Saturday, Ihrch 29, 1975, breaker "lC" tripped due OCCUIEI:CE:
to a fault on bus "1C".
Power to Reactor Protection System I was reestablished by transferring power feed from the MG set to the transformer and the scram was reset. Subsequently, all breakers on "1C" were racked out and the tie bre scrs were closed to feed the Unit Substations (USIA1, USIA2, USIA3).
e APPARENT CAUSE Design Procedure OF OCCUIU E CE:
Fanufacture Unusual Service Conditicn Installation /
Inc. Environmental Construction X
Component Failure Operator Other (Specify)
Uhc trip of "lC" breaker was discovered to be caused b'/ a fault on cable nurber 86-25 (Burns and Roe Drawing //3002, Shoot 1).
e AbnonraLOccurrence 3
Beport No. 50,-219/i5/9 t.
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his is the cable tie between "10" bus and the DG #1 breaker.
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One of the t':o phase "A" leads was discovered grounded between I
the "1C" bus and DG #1 breaker. %e cable installed is Vulkene f
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t insulated and shielded, #SI-580611, rated at 51W. Fault on the I
cable caused 86/1C lockout to trip breaker "10" with subsequent 1
loss of equip: rent connected to "1C".
Failure of the cable between the DG #1 breaker and bus "1C" NJALYSIS OF resulted11n c. loss of standby emergency power to bus "10".
In
- OCCURREliCE
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addition, the fault en bus "1C" resulted in a temporary loss of
'I one-ha3f the safety systems associated with the emergency busses.
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Had-a condition called for the operation of the safety systems, the redundant systems uould have been available to operate.
In addition, th2 redundant diesel generator was available to supply 1
power to the redundant safety systems on a coITplete loss of out-side power sources.
Appendix L to the FDSAR contains a probability analysis regarding the availability of standby cooling systems and includcs an l
analysis of off-site power availability concurrent with a loss i
of coolant accident. he results indicated that the reliability of available power from off-site sources or from a self-contained unit - only one (1) diesel generator was considered in the analysis - was quite high. Since the station is provided with two (2) separate diesel generator units, having one (1) unit I
out of service has no effect at all upon the results of the 3
analysis. In addition, the effects of single bus operation during a loss of coolant accident was analysed in Amendment 32 to the FDSAR and the unit loading under this condition was found J
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b_ withi the norm 1 KVA rating of the diesel generator. Thus,,
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there is no additional safety significance associated with this event beyond that al_ ready analyzed.
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See " Apparent Cause of Occurrence" for details on ccble involved -
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