ML20148C824

Rev 1 to Special Rept:On 871113,invalid Failure of Diesel Generator 1A Occurred.Caused by Pneumatic Shutdown Board Logic Element & Miscellaneous Air Leaks in Sys.Components Replaced & Air Leaks Corrected

ML20148C824
Person / Time
Site:	Catawba
Issue date:	03/17/1988
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8803230128
Download: ML20148C824 (2)

Text

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.x DUKE POWER GOMPANY -

P.O. BOX G3100 CHAMLOTTE, N.C. 28242 UAL B. TUCKER rzLzmown vws ramespent (704) 07:F4538 mtrtaan ruominion March 17, 1988 Document Control Desk U. S. Nuclear Regulatory Commission .

Washington, D. C. 20555 Subj ect: Catawba Nuclear Station, Unit 1 Docket No. 50-413 Revision to Special Report Gentlemen:

Pursuant to Technical Specification 3/4.8.1.1.3, please find attached Revision 1 to the Special Report concerning an invalid failure of diesel generator 1A which took place on November 13, 1987. This failure was initially categorized as an Invalid Test. The failure was reclassified as an invalid failure upon completion of a review on December 9, 1987. Changes to the original report, which was submitted to the NRC per my January 7, 1988 letter, are indicated by sidebars.

Very truly yours,

'o 0ImLA n' p iia 1 B. Tucker JGT/10005/sbn Attachment xc: Dr. J. Nelson Graco, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. P. K. Van Doorn NRC Resident Inspector Catawba Nuclear Station h

1 8803230128 G80317 h l PDR ADOCK 05000413 \

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SPECIAL REPORT, REVISION 1 CATAWBA NUCLEAR STATION, UNIT _1 DIESEL-GENERATOR 1A INVALID FAILURE ON NOVEMBER 13, 1987 9

On November 13, 1987, after completing an 18 month mechanical inspection and-overhaul, D/G 1A testing was begun to perform break-in runs. During this testing, on start number 548, the D/G tripped after one minute due to pneumatic control problems. Subsequent start attempts were all successful, and the post overhaul break-in runs were completed by Duke Power Mechanical Maintenance personnel.

This failure was initially categorized as an Invalid Test. Unit 1 was in Mode 6, Refueling, at the time of this event.

Testing was conducted to verify D/G 1A operability after the implementation of a modification during the overhaul and to perform the 18 month Periodic Test.

While conducting the test a failure to start occurred. Work Request 26135 OPS 4

Las written to investigate and repair the problem. Duke Power technicians traced the problem to pneumatic valve "P-3", its shuttle valve, pneumatic shutdown board logic element "AND 14", logic element "NOT 18", and miscellaneous air leaks in the system. These components were replaced and the air leaks corrected.

Thirty consecutive starts were performed following overhaul and D/G 1A had no further automatic trips. The D/G was inoperable 62 hours7.175926e-4 days <br />0.0172 hours <br />1.025132e-4 weeks <br />2.3591e-5 months <br /> and 42 minutes (frcm November 18, at 1311 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.988355e-4 months <br /> until November 21, at 0353 hours0.00409 days <br />0.0981 hours <br />5.83664e-4 weeks <br />1.343165e-4 months <br />).

The replaced components have several functions. Pneumatic valve "P-3" and its shuttle valve are used to enable a low-low lube oil pressure trip and reset that trip during start of the D/G. Logic element "AND 14" is used to enable the non-emergency trips after approximately one minute of run time. Logic element "NOT 1A" is used to accomplish shutdown of the D/G upon receipt of an on-engine trip signal.

This failure was initially categorized as an Invalid Test because it was the I first test conducted after repairs were made to the D/G Control Air system.

Further review determined that since no maintenance had been performed on these

individual logic components and that the problems had been discovered during the i break-in runs, the start attempt constituted an Invalid Failure per Regulatory

! Guide 1.108. The failure was reclassified as an invalid failure upon completion l of the subject review on December 9,1987. This was the third failure within the

! last one hundred starts of Unit 1A D/Gs. Therefore, in accordance with Technical Specification 4.8.1.1.2 the testing interval was set at 30-day intervals.

l The health and safety of the public were unaffected by this event.

l l

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