ML20148C805

Rev 1 to Special Rept:On 871201,diesel Generator 1B Valid Failure Occurred.Caused by P-3 Shuttle Not Operating Properly.Repairs Completed on Shuttle Valve & Generator Tested.Gates Installed & No Further Tripping Experienced

ML20148C805
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 8803230119
Download: ML20148C805 (2)

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. DUKE POWER GOMPANY P.O. BOX 33189 CHARLOTTE. N.O. 28949 r HALH.TUCKEH TELEPHONE wwa reemment (704) GN831 wtusAn renotworion

. March 17, 1987 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

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

Pursuant to Technical Specifications 4.8.1.1.3 and 6.9.2, please find attached Revision 1 to the Special Report concerning a Diesel Generator 1B valid failure on December 1, 1987. Changes to the original report, which was submitted to the NRC per my December 31, 1988 letter, are indicated by sidebars.

Very truly yours, b LL .p t-

-Hal B. Tucker JGT/10006/sbn Attachment /

xc: Dr. J. Nelson Grace Regional Administrator, Region II U.~ S. Nuclear Regulatory Commission L

101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. P. K. Van Doorn r NRC Resident Inspector Catawba Nuclear Station I

8803230119 880317 i l

PDR ADOCK 05000413 1j s DCD <

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SPECIAL REPORT, REVISION 1 CATAWBA NUCLEAR STATION, UNIT 1 DIESEL GENERATOR 1B VALID FAILURE ON DECEMBER 1, 1987 On December 1, 1987 while performing Train B Engineering Safeguards Features (ESP) Testing, Unit 1 Diesel Generator (D/G) 1B was started automatically from the. Unit 1-Control Room. After approximately 70 seconds the D/G tripped. ihis was the fifth Valid failure within the last 100 Valid starts of D/G 1B and the second in the last 20 starts. Consequently the testing interval was set at 7 days in accordance with Technical Specification 4.8.1.1.2. A work request was initiated to investigate the problem. The problem was found to be the P-3 shuttle valve not operating correctly. Repairs were completed on the shuttle valve and the D/G was tested satisfactory. Further investigation was conducted by Duke Power Design Engineering personnel and Transamerica Delaval, Incorporated, personnel in order to determine an appropriate replacement for the subject shuttle valve due to its repeated failures. It was decided that an OR gate, similar to the ones used on the Pneumatic Control Logic Board would perform the same function as the shuttle valve. The function of the shuttle valve is to enable a low low lube oil pressure trip and reset that trip during the start of the D/G. It was also determined that the OR Gate was a better design and more efficient component than the shuttle valve. Testing was conducted on D/G IB using an OR Gate in place of the P-3 shuttle valve. It was found that the OR

- Gate operation was superior to the shuttle valve operation. A Nuclear Station Modification was written to install the OR gates in both Unit 1 and 2 D/Gs control panels at Catawba. Further test starts were conducted after implementation of the NSM on D/G 1B (before it was declared operable). At this time the OR gates have been installed on the Catawba D/Gs and no further indication of the tripping problem has been experienced.

The D/G was declared inoperable at 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> on December 1, 1987, and was declared operable at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> on December 5, 1987. This is a total of 106 hours0.00123 days <br />0.0294 hours <br />1.752645e-4 weeks <br />4.0333e-5 months <br /> and 30 minutes. Because the Unit was in Mode 6. Refueling, Technical Specification 3.8.1.2, which has no time stipulations on returning an out of service D/G, was applicable. No Technical Specification Violations occurred as a l

result of this event.

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