ML20116B841

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Forwards Revisions to SR 95-03,SR 95-04 & SR 95-05 Re EDG 1-2 Valid Failures
ML20116B841
Person / Time
Site: Diablo Canyon Pacific Gas & Electric icon.png
Issue date: 07/22/1996
From: Powers R
PACIFIC GAS & ELECTRIC CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20116B844 List:
References
DCL-96-155, NUDOCS 9607300304
Download: ML20116B841 (2)


Text

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q Pacific Gas and Electric Company Diablo Canyon Power Plant Robert P. Powers ,

_J P0. Box 56 Vice President-Diablo Canyon

- Avila Beach, CA 93424 Operations and Plant Manager 805/545-6000 k '

July 22,1996 PG&E Letter DCL-96-155

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U.S. Nuclear Regulatory Commission

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ATTN: Document Control Desk Washington, D.C. 20555 l Docket No 50-275, OL-DPR-80

Diablo Cr 1 Unit 1 Specialli c196-02. Emeroency Diesel Generator 1-2 Valid Failures 4

Dear Commissioners and Staff:

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2 in accordance with the requimments of Diablo Canyon Power Plant Technical Specifications (TSs) 6.9.2 and 4.8.1.1.4 and Revision 1 to NRC Regulatory Guide 1.108, PG&E is submitting the enclosed revisions to Special Reports (SR)

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regarding Emergency Diesel Generator (EDG) 1-2 valid failures.

Enclosure 1 contains a revision to SR 95-03 previously submitted via DCL-95-158 on July 28,1995. Thls enclosure provides information on Emergency Diesel Generator (EDG) 1-2 failure to sucessfully load on June 21, 1995, due to degraded voltage regulator performance.

3 Enclosure 2 contains a revision to SR 95-04 previously submitted via DCL-95-174 on August 17,1995. This enclosure provides information on EDG 1-2 load swings on July 18,1995, due to a defective electronic governor stability j potentiometer. PG&E has determined that this event was not a valid failure.

Enclosure 2 contains additional information on the basis for this determination. ..,

Enclosure 3 contains a revision to SR 95-05 previously reported via DCL-95-05 { ,

on September 1,1995. This enclosure provides information on EDG 1-2 failure g to achieve rated output frequency within TS 4.8.1.1.2 time limits, on August 6 Jq and 7,1996, due to degraded electronic governor performance l

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l 4 PG&E is submitting revisions to the above SRs to provide information on the 4

i results of the root cause analysis and corrective action determination. Changes are indicated by revision bars in the margins,

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i 4 I 9607300304 960722 I PDR S

ADOCK 0500o275 PDR [h ( o d

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1 Docum:nt Control Desk July 22,1996 Page 2 As of April 1,1996, the total number of valid failures in the last 100 valid tests for EDG 1-2 is 3, and the total number of valid failures in the last 20 valid tests for EDG 1-2 is 0; therefore, an accelerated testing schedule is not required. The first of the 3 valid failures in the last 100 valid tests for EDG 1-2 occurred on June 21,1995, and was reported to the NRC on September 1,1995, via DCL-95-158. The second of the three valid failures occurred on August 6,1995, and was reported to the NRC on September 1,1995, via DCL-95-188. The third of the 3 valid failures occurred on August 7,1995, and was reported to the NRC on September 1,1995, via DCL-95-188.

Between June 21,1995, and April 1,1996, PG&E has conducted 43 STP M-9As.

During this period of time, EDG 1-2 was operated for a total of 275 hours0.00318 days <br />0.0764 hours <br />4.546958e-4 weeks <br />1.046375e-4 months <br />.

l Although DG 1-2 has returned to a 31 day test interval in accordance with TS, PG&E has placed DG 1-2 in the Goal Setting Program of the Maintenance Rule  !

implementation. This action will enhance system engineering and maintenance personnel awareness of DG 1-2 performance trends in order to funher improve reliability results.

These conditions did not affect the health and safety of the public.

Sincerely, b h Robert P. Powers cc: Steven D. Bloom L. J. Callan Kenneth E. Perkins Michael D. Tschiltz Diablo Distribution INPO Enclosures N0001904 SDL/2245