ML20195H142

Special Rept:On 871007,diesel Generator 1B Started Automatically from Control Room.After Approx 70 S,Diesel Tripped Automatically.Caused by Defective Components (P-3 & Shuttle Valve).Components Replaced

ML20195H142
Person / Time
Site:	Catawba
Issue date:	01/06/1988
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8801150217
Download: ML20195H142 (2)

Text

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DUKE Powna Go31mn-15.0. ISOX 331tlO Cal AltLOTTE, N.O. 2112 4 2 IIAL II, TUCKER TELarnown vna essaamers asnaAs enominion (704) 0 F'}4631 January 6, 1988 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

Catawba Nuclear Station, Unit 1 Docket No. 50-413 Special Report Gentlemen:

Please find attached a revision to the Special Report submitted per my November 6, 1987 letter concerning a valid failure of diesel generator 1B which took place on October 7, 1987. The original report was submitted pursuant to Technical Specification 4.8.1.1.3.

Very truly yours, h k,/ "

Hal B. Tucker JGT/1210/sbn Attachment xc: Dr. J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Mr. P. K. Van Doorn l NRC Resident Inspector Catawba Nuclear Station h

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880115021'1 880106 i PDR ADOCK 05000413

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s, ,s SPECIAL REPORT CATAWBA NUCLEAR STATION, UNIT 1 VALID FAILURE OF DIE 3EL GENERATOR 1B ON OCTOBER 7, 1987 On October 7, 1987 while performing the Engineering Safeguards Testing, Diesel Generator '1B' was started automatically from the Unit 2 Control Room. After approximately 70 seconds the Diesel tripped automatically. This failure was the fourth valid failure within the last 100 valid tests of Diesel Generator 'lB'.

Work Request 25806 OPS was initiated to investigate the problem. After several days of testing the cause of the trip was not determined. Due to time constraints going into the outage, the scheduled tear down and inspection was started on the Diesel.

During the tear down and inspection extensive trouble shooting was conducted by Duke Power and Vendor personnel. During the maintenance period nothing was found defective that would have caused the tripping of the diesel on automatic starts.

Once the work was completed,' Duke Power personnel conducted extensive testing of the diesel. The diesel again tripped on an automatic start. Additional instrumentation was in place in the control system during these starts. The additional instrumentation provided some indication of the problem areas. The suspected components (P-3 and shuttle valve) were previously replaced and both components were again replaced. The diesel was again tested to see if the problem was corrected. 31 consecutive automatic starts were performed with no trips.

At this time, it is believed that the new replacement suspected components were defective. This allowed the control air pressure to dip momentarily below the trip point causing the diesel to trip when sequencing through the first two minutes of the diesel start.

The health and safety of the public were not affected by this event.