ML20028E078

LER 82-078/03X-1:on 821125,w/unit in Mode 3,120-volt Ac Vital Bus 1-IV Lost Voltage.Caused by Failure of Normal Power Supply Inverter 1-VB-I-04,due to Failed Oscillator Board,Transformer & Fuse.Components Replaced

ML20028E078
Person / Time
Site:	North Anna
Issue date:	01/11/1983
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20028E072	List: ML20028E071 ML20028E078
References
LER-82-078-03X, LER-82-78-3X, NUDOCS 8301200330
Download: ML20028E078 (2)

Text

'UPDA E REPORT - Previous Report Date 12-15-82 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/ /V/A/N/A/S/1/ (2) /0/0/-/0/0/0/0/0/-/0/0/ (3) /4/1/1/1/1/ (4) / / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT 0/1/ R OUR /L/ (6) /0/5/0/0/0/3/3/8/ (7) /1/1/2/5/8/2/ (8) /0 /1/1/1/8 /3 / (9)

DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/ / On November 25, 1982, with Unit 1 in Mode 3, 120-Volt A.C. Vital Bus 1-IV lost /

/0/3/ / voltage due to the failure of its normal power supply inverter 1-VB-I-04. Since /

/0/4/ / the alternate supply to Vital Bus 1-IV via Voltage Regulating transformer, trans-/

/0/5/ / 80, was still available and was used, the health and safety of the public were /

/0/6/ / not affected. This event is contrary to T.S. 3.8.2.1 and reportable pursuant to /

/0/7/ / T.S. 6.9.1.9.b. /

/0/8/ / /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /E/B/ (11) /E/ (12) /A/ (13) /G/E/N/E/R/A/ (14) /F/ (15) /Z/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO. CODE TYPE NO.

(17) REPORT NUMBER /8/2/ /-/ /0/7/8/ /ssf /0/3/ /X/ /-/ /1/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/A/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) /Y/ (23) /N/ (24) /A/ (25) /S/2/5/0/

(26) i CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / 120 Volt A.C. Vital Bus 1-IV lost voltage due to a failure of its normal supply /

/1/1/ / inverter 1-VB-I-04. Power supply to Vital Bus 1-IV was manually switched to the /

/1/2/ / Voltage Regulating Transformer. The inverter was exanined and found to have a /

/1/3/ / failed oscillator board, transformer and fuse. These components were subsequent-/

/1/4/ / ly replaced and the inverter tested satisfactorily. /

FACILITY METHOD OF STATUS  % POWER DISCOVERY DESCRIPTION (32)

/1/5/ /G/ (28) /0/0/0/ (29) / OTHERNA STATUS

/ ( } DISCOVERY

/A/ (31) / Operator Observation /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36)

/1/6/ /Z/ (33) /Z/ (34) / NA / / NA /

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Z/ (38) / NA /

, PERSONNEL INJURIES

! NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) / NA /

LOSS TYPE OF OR DAMAGE TO FACILITY (43)

DESCRIPTION

/1/9/ /Z/ (42) / NA /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY

/2/0/ /N/ (44) / NA /////////////

\RER W. R. CARTWRIGHT PHONE (703) 894-5151 8301200330 830111 PDR ADOCK 050003 8 S

. ~,

> b UPDATE REPORT -

Previous Report Date 12-15-82 Virginia Electric and Power Company North Anna Power Station, Unit No. 1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 82-078/03X-1 Description of Event On November 25, 1982, with Unit 1 in Mode 3, 120-Volt A.C. Vital Bus 1-IV lost voltage due to the failure of its normal power supply inverter 1-VB-I-04. The supply to Vital Bus 1-IV was subsequently switched to the backup power supply, voltage Regulating transformer 80.

Probable Consequences of Occurrence

120 Volt A.C. Vital Bus 1-IV supplies power to vital

]'

instrumentation and protection systems. Since Vital Bus 1-IV was energized via the alternate power supply, transformer 80, upon the failure of the normal power supply, inverter 1-VB-I-04, the health and safety of the public were not affected. This event is contrary to T.S.

6.9.1.9.b.

Cause of Event The event was caused by the failure of the normal power supply to 120-Volt A.C. Vital Bus 1-IV, inverter 1-VB-I-04.

Immediate Corrective Action Power supply to 120 VA.C. Vital Bus 1-IV was manually switched to I

Voltage Regulating transformer 80. Inverter 1-V-I-04 was examined and found to have three failed internal components; a fuse, oscillator board and a transformer. The components were subsequently replaced and the

inverter tested satisfactorily. The inverter was then returned to service.

Scheduled Corrective Action There are no scheduled corrective actions.

Actions Taken to Prevent Recurrence No actions are required to prevent recurrence.

Generic Im>l1 cations There are no generic implications from this event.

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