ML20065R821

RO:901114,during Performance of Monthly Operability Surveillance of Diesel Generator 2A,noted That Voltage Indication on Panel Appeared to Be Erroneous.Caused by Failure of Fuse.Fuse Replaced

ML20065R821
Person / Time
Site:	Braidwood
Issue date:	12/13/1990
From:	Checca A COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 9012190188
Download: ML20065R821 (2)

Text

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' - Commonweal'h Edison A(

1400 Opus Place i Downers Orave, tilinois 60515 December 13, 1990 Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulatory Commission Region 111 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Braidwood Station Unit 2 Diesel Generator 2DG0lKA Failures NRC_DELttJom 50_-451__

Reference:

(a) NUREG-1276, Technical Specification (b) June 8, 1990, S.C. Hunsader letter to A.B. Davis

Dear Mr. Davis:

Section 4.8.1.1.3 of reference (a) requires that all diesel generator failures, valid or non-valid, be reported to the NRC pursuant to Specification 6.9.2. The enclosure provides the report that addresses one valid test failure experienced on diesel generator 2DG0lKA. The criteria used to determine valid tests and failures is taken from section C.2.e of Regulatory Guid 1.108.

Reference (b) is the most recent report addressing diesel generator failures, submitted per Section 4.8.1.1.3.

Please direct any questions concerning this submittal to this office.

Very Trul yours, f " r~--  ;

A.R. Checca Nuclear Licensing Administrator cc: R. Pulsifer-NRR H. Shafer-Rill Resident Inspector-Braidwood

NRC DocumentLControl' Desk ZNLD:672:rg ((2 2 9012190188 901213 n PDH ADOCK 05000457 / ;

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, i a j' 2A DG FAILURE REPORT At 0814 on November 14, 1990, the 2A Diesel Generator (DG) was started to perform its monthly operability surveillance, 2Bw05 8.1.1.2.a-1.

During the timing of the start, it was noted that the voltage indication on the local control panel and the frequency indication on the main control room panel appeared to be erroneous. The DG was shut down seventeen seconds into the run.

Subsequently all the fuses in the indication and control circuitry were checked. All the fuses appeared to be good. At 1035 a maintenance /

troubleshooting run was performed. At this time, all indications appeared normal. A nuclear work request was generated to determine the cause of the failure. Later, while troubleshooting, one of the fuses on the secondary side of the potential transformer was found to be open, it was discovered that the fuse had failed in an intermittent manner. The bad fuse was replaced.

At 0227 on November 15, 1990, a maintenance run was performed.

Voltage and frequency indications appeared normal. The 2A DG was loaded to 1500 kw to verify proper control. All controls operated properly. The DG was unloaded and shutdown normally.

The 2A DG was started for its operability surveillance. The one hour run at 25500 kw was completed at 1122 on November 15, 1990. The 2A DG was shutdown at 1134 and declared operable at 1230 on November 15, 1990.

The failure of the 2A DG has been determined to be valid in accordance with Regulatory Guide 1.108. This failure is the second valid failure in the last fourteen valid tests. The 2A DG has been placed on an increased surveillance frequency per Technical Specification table 4.8-1.

Pursuant to Regulatory Guide 1.108, position C.3.6.7, as of November 15, 1990, the 2A DG has had four valid failures and the 2B DG has had one valid failure in the last 100 Unit 2 valid DG starts.

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