05000280/LER-1980-029-03, /03L-0:on 800603,during Normal Operation,Vital Bus 4 Sola Failed,Initiating Automatic Turbine Runback.Caused by Failure of Filtering Capacitor in Sola Tranformer.Vital Bus re-energized.Transformer Replaced

/03L-0:on 800603,during Normal Operation,Vital Bus 4 Sola Failed,Initiating Automatic Turbine Runback.Caused by Failure of Filtering Capacitor in Sola Tranformer.Vital Bus re-energized.Transformer Replaced

ML18139A408
Person / Time
Site:	Surry
Issue date:	07/02/1980
From:	Joshua Wilson VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18139A407	List: 05000280/LER-1980-029, Forwards LER 80-029/03L-0 05000280/LER-1980-029-03, /03L-0:on 800603,during Normal Operation,Vital Bus 4 Sola Failed,Initiating Automatic Turbine Runback.Caused by Failure of Filtering Capacitor in Sola Tranformer.Vital Bus re-energized.Transformer Replaced
References
LER-80-029-03L-01, LER-80-29-3L-1, NUDOCS 8007070229
Download: ML18139A408 (2)

LER-1980-029, /03L-0:on 800603,during Normal Operation,Vital Bus 4 Sola Failed,Initiating Automatic Turbine Runback.Caused by Failure of Filtering Capacitor in Sola Tranformer.Vital Bus re-energized.Transformer Replaced

Event date:
Report date:
2801980029R03 - NRC Website

text

LICH~SEE EVEN"f F.EPORT

'CONTROL BLOCK:

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60 61 DOCKET NUMBER 68 69 EVENT DATE

74.

75 REPORT DATE 80 EVENT DESCRIPTION ANO PROBABLE CONSEQUENCES@

8 l During normal operations at 100% power Vital Bus IV Sola failed initiating an automatic turbine runback. The reactor tripped on steam generator lo level with feed water mismatch. A safety injection was initiated on hi steam line flow with lo Tave.

A second I safety injection was initiated due to an unsuccessful cross connect attempt to re-energize Vital Bus IV in which Vital Bus II was lost. This is report ab le p1.1rsuant to T.S. 6.6.2b.l. The system performed its design function therefore the health and safety of the general public were not jeopardized.

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CAUSE DESCRIPTION ANO CORRECTIVE ACTIONS @

42 43 44 I A filtering capacitor in the Sola-transformer failed and caught fire damaging the Sola and causing loss of power to Vital Bus IV.

The Vital Bus was re-energized and the

.l transformer replaced.

The Unit was returned to power.

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50-280 REPORT NO:

80-029/0JL-O

'EVENT DATE:

6-3-80 TITLE OF REPORT:

1.

Description of Event

SAFETY INJECTION INITIATION During normal operations at 100% power Vital Bus IV Sola Transformer failed1 initiating an automatic turbine runback.

Automatic control to FCV-1478, FCV-1488, and FCV-1498 was. lost with the failure of the Bus.

This produced a lo feedwater level in steam generator lC and feedwater mismatch.

These conditions tripped the reactor and the turbine tripped on the reactor trip. 1,I.'he loss of Vital Bus IV caused the safety circuitry for Hi steam line flow to activate and combined with lo Tav~initiated a Safety Injection.

Vital Bus II was lost in an unsuccessful cross connect attempt to re-energize Vital Bus IV.

Power to one channel of pressure trans-mitters was lost with the failure of Vital Bus IV.

Vital Bus II supplies power to a second channel of pressure transmitters.

Loss of Vital Bus II completed a 2 out of 3 logic matrix, initiating a safety injection.

This event is reportable in accordance with T. S. 6. 6. 2b. 1.

2.

Probable Consequences and Status of Redundant System:

Loss of Vital Bus IV induced conditions that initiated the use of certain reactor safeguards.

The system performed its design function therefore the health and safety of the general public-were not jeopardized.

3.

Cause

A filtering capacitor in the Sola transformer failed and caught fire damaging the Sola and causing loss of power to Vital Bus IV.

4.

Immediate Corrective Action

Vital Bus II was lost in an unsuccessful cross connect attempt to re-energize Vital Bus IV.

Vital Bus II was re-energized, then Vital Bus IV was successfully energized from Vital Bus II.

The Sola transformer was replaced and Vital Bus IV returned to its no?='ffial power supply.

5.

Subsequent Corrective Action:

There were no subsequent corrective actions.

6.

Action Taken to Prevent Recurrence:

A preventative maintenance procedure will be implemented for periodic check and cleaning of the capacitors.

7.

Generic Implications:

There has been only one previous problem with the Sola transformers; however, due to the infrequency of the events, there are no generic implications.