05000296/LER-1980-007-03, /03L-0:on 800301,after Offsite Power Was Restored to 4-kV Bus Tie Board,Short Period of Time Elapsed Before Reclosure of Bus Tie Boarder Feeder Breaker.Apparent Disagreement in Time Is Still Being Investigated

/03L-0:on 800301,after Offsite Power Was Restored to 4-kV Bus Tie Board,Short Period of Time Elapsed Before Reclosure of Bus Tie Boarder Feeder Breaker.Apparent Disagreement in Time Is Still Being Investigated

ML18024B442
Person / Time
Site:	Browns Ferry
Issue date:	03/28/1980
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18024B441	List: 05000296/LER-1980-007, Forwards LER 80-007/03L-0 05000296/LER-1980-007-03, /03L-0:on 800301,after Offsite Power Was Restored to 4-kV Bus Tie Board,Short Period of Time Elapsed Before Reclosure of Bus Tie Boarder Feeder Breaker.Apparent Disagreement in Time Is Still Being Investigated
References
LER-80-007-03L-02, LER-80-7-3L-2, NUDOCS 8004010402
Download: ML18024B442 (4)

LER-1980-007, /03L-0:on 800301,after Offsite Power Was Restored to 4-kV Bus Tie Board,Short Period of Time Elapsed Before Reclosure of Bus Tie Boarder Feeder Breaker.Apparent Disagreement in Time Is Still Being Investigated

Event date:
Report date:
2961980007R03 - NRC Website

text

LEAR REOLzz-ATORY COMMISSION NRC4F ORAN' P77l

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LICENSEE CODE 14 15 LICENSE NUMBER 25 26 LICENSE TYPE 30 57 CAT 58 CON'T

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0 00 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Q10 During normal operation an ice storm caused the loss of offsite power to the 4 kQ bus tie board.

After offsite power was restored there was a short period of 4

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~os time before reclosure of the bus tie board feeder breaker.

Reference Technical Specification 3.9.B.

The diesel generators started.

There was no danger to health an safety'f the public.

No previous occurrences.

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CODE TYPE NO.

Q11 8510111

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33 34 35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION ANDCORRECTIVE ACTIONS Q27 o

Loss of both 161-kV lines interru ted ower to coolin tower transformers and 4-kV switch ear feeding bus tie board.

The feeder breakers were reclosed.

The apparent 1

disagreement in time between return of 161-kV lines and reclosure of bus tie board 3

feeder breakers is still being investigated.

80 ME THDD OF DISCOVERY DISCOVERY DESCRIPTION 37 Q31 Events recorder printout 45 46 LOCATIONOF RELEASE QB NA 80 44 45 80 80 80 NRC USE ONLY offsite power 80 8

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FACILITY STATUS 98 POWER OTHER STATUS Q 5

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10 11 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION A3

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11 12 13 PERSONNE L INJURIES 7

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11 12 LOSS OF OR DAMAGE To FACH.I TY Q43 TYPE

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'Tennessee Valley Authority Browns Ferry Nuclear Plant Form BF-17 BF 15.2 1/10/79 LER SUPPLEMENTAL INFORMATION BFRO 296 / 8 Technical Specification Involved

'i'eported Under Technical Specification Date of Occurrence 3/ /

Time of Occurrence Unit Identification and Description'of Occurrence:

Due to an ice storm both 161-kV lines were lost causing a loss of power to the cooling tower transformers and 4-kV switchgear feeding the bus tie 'board.

After offsite power was restored there was a short period of time before reclosure of the bus tie board feeder breakers.

Conditions Prior to Occurrence:

Unit 1 8 0% refueling outage Unit 2 9 0% cold shutdown Unit 3 8 98%

Action specified in the Technical Specification Surveillance Requirements met due

~to ino arabia ecLuipment.

Describe.

Regulatory Guide 1.93 allows, under certain conditions, continued operation at'ull or'reduced power for a limited time than to effect an immediate shutdown on the loss of required electric power sources.

Apparent Cause of Occurrence:

The loss of offsite power was due to the ice and wind storm.

Analv.",is ol'ccurrence:

There was no ctamage to plant equtpment.

There was no acttvttp release, no personnel exposure or in)ury and no danger to health or safety of the public.

Corrective Action

Offsite power was restored and bus tie board feeder breakers reclosed.

The apparent disagreement in time between return of offsite power and reclosure of feeder breakers is still being investigated.

Failure Data:

NA

• Reten t ion:

• Revision:

eriod - Lifetime; Responsibility - Administrative Supervisor

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