ML20245D872

Ro:On 890215,diesel Generator Voltage & Frequency Indications Malfunctioned.Caused by Blown Fuse in Strip Chart Recorder.Generator Run Manually Terminated & Fuse Replaced

ML20245D872
Person / Time
Site:	Braidwood
Issue date:	04/14/1989
From:	Hunsader S COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 8905010206
Download: ML20245D872 (2)

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Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulatory Commission i Region III 799 Roosevelt Road Glen Ellyn, IL 60137 l

Subjects eBraidwood Station Unit 12' '

, Diesel.cGoneratorLIDG01KB Failu' reb NRC Docket No. 50-457' References (a) NUREG-1276, Technical Specification, (b) October 28, 1988, S.C. Hunsader letter to A.B. Davis Dear Mr. Davis l Section 4.8.1.1.3 of reference (a) requires that all diesel ge.lerator failures, valid or non-valid, be reported to the NRC pursuant to Specification l 6.9.2. The enclosure provides the report that addresses one invalid test '

failure experienced on diesel generator 2DG01KB. )

l 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 matter to this office.

Very truly yours, S.C. Hunsader '

Nuclear Licensing Administrator

/sc1:0081T 1 cc: S. Sands-NRR Resident Inspector-Braidwood h

NRC-Document Control Desk

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, 2B D/G INVALID FAILURE REPORT On February 15,1989, at 2039, the 2B Diesel Generator was started in performance of the Monthly Operability Surveillance 2BwOS 8.1.1.2.a-2 using a manual SI signal. A strip chart recorder was connected at the local control panel to record the starting time. Localindication showed that the Diesel Generator came up to speed, voltage and frequency, but immediately therafter, the voltage and frequency indications malfunctioned. The Diesel Generator run was then manually terminated. Due to three identical situations occurring previously on the 2A Diesel Generator when using a strip chart recorder, the secondary potential transformer fuse, which is located just upstream of the strip chart connections, was inspected. The fuse was found blown and was replaced. A continuity check of the strip chart recorder indicated no dead grounds. A second start attempt was performed at 2125 and produced identical results. The fuse was again replaced and the strip chart recorder connections were removed from the local control panel. The surveillance was restarted at 2139 using stopwatches to time the Diesel Generator start. The Diesel Generator operated as designed and the surveillance was completed at 2259. A Modification Request has been initiated to engineer and install terminal points for strip chart connections which will be electrically isolated from the Diesel Generator circuitry. This failure has been attributed to an intermittent short in the strip chart recorder and has been determined to be invalid in accordance with Regulatory Guide 1.108, Sectica C.2.e.2.

The 2A and the 2B Diesel Generator are currently being tested monthly in accordance with Technical Specification 4.8.1.1.2. The 2A Diesel Generator has had 3 valid falhares in its 42 valid tests since the completion of pe-operational testing. The 2B Diesel Generator has had no valid failures in its 22 valid tests since the completion of pre-operational testing.

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