ML19319D030

LER 78-028/03L-0:on 780425,vital Bus 3A Circuits Found Improperly Fused.Caused by Incorrect Fuse Installation. Busses (120 Volt) Checked to Ensure Agreement W/Engineering Drawings

ML19319D030
Person / Time
Site:	Crystal River
Issue date:	05/15/1978
From:	Cooper J FLORIDA POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19319D028	List: ML19319D027 ML19319D030
References
LER-78-028-03L, LER-78-28-3L, NUDOCS 8003040953
Download: ML19319D030 (2)

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i ,,,2, g At 111_5 during the investigat3.on of inverter 3A trionine. it was discovered g , that 5 circuits of vital Bus 3A vere improcerly fused. No hazard to the I m , health and safety of the general public as there are circuit breakers I

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CAust otSCAirrtCN AND CoaaECrit! AcrtOA5 7 i.,oi[The cause of this event was due to the installation of incorrect fuses in f l

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. SUPPLEMENTARY INFORMATION

1. 50-302/78-028/03L-0  !

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2. ( 1111ty: Crystal River Unic #3

3. Report Date: 15 May 1978

4. Occurrence Date: 25 April 1978

5. Identification of occurrence:

Improper fuses installed in Vital Bus 3A.

6. Conditions Prior to Occurrence:

Mode 6 refueling.

7. Description of Occurrence:

At 1115 during the investigation of inverter 3A tripping, it was discovered that five (5) circuits of Vital Bus 3A were improperly fused. Discrepancy Report DR-533 was initiated to install proper fuses in Vital Bus 3A as indicated on 120 Volt AC Vital

. Bus 3A drawing #201-063, rev. 7. DR-533 also initiated an investigatien into the three (3) r - 4ning 120 volt Vital Busses to ensure that proper fuses have been I installed as indicated on the applicable drawings.

8. D:signation of Apparent Cause:

The cause of this event was due to the installation of incorrect fuses in Vital Bus N 3A circuits during the construction and testing phase.

9. Analysis of Occ'urrence:

No hazard to the health and 9afety of the general public as vital Bus 3A circuits were still protected because there are circuit breakers vired in series with the fuses.  ;

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10. Corrective Action:

Plant operating records were thoroughly searched in an effort to determine when the incorrect fuses were initially installed. The results of this invest 1gation revealed that the fuses were not installed during the operational phase of the plant. An investigation was also made into the three (3) remaining 120 Volt Vital Busses to ensure that proper fuses have been installed as indicated on applicable engineering drawings.

11. Failure Data:

First occurrence of as event of this type.

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