ML20087H251
| ML20087H251 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/14/1995 |
| From: | Geoffrey Edwards PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9508170380 | |
| Download: ML20087H251 (2) | |
Text
Ccrrett C E' war:33 y'
Plant Manager Peach Bottom Atomic Power fataaon O
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EN RGY ecco tee,0< ceene",
FID 1, Box 208 DeKa, PA 17314-9739 717 450 4244 August 14, 1995 Docket Nos.
50-277 50-278 Ucense Nos.
DPR-44 DPR-56 Document Contrc.' Desk U. S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Peach Bottom Atomic Power Station - Unit 2 & 3 Special Report for a Non-Valid Failure of the E-3 Emergency Diesel Generator on 7/26/95
REFERENCE:
Peach Bottom Atomic Power Station Technical Specification (Tech Spec) 4.9.A.1.2.L and M This Special Report is submitted pursuant to the requirements of Tech Spec 4.9.A.1.2.M. This Surveillance Requirement requires reporting of all emergency Diesel Generator (D/G) failures, valid or non-valid, within 30 days. This report is required to include the information recommended in Regulatory Position C.3.d of Regulatory Guide (RG) 1.108 " Periodic Testing of Diesel Generator Units as Onsite Electric Power System at Nuclear Power Plants", Revision 1, August 1977.
On 7/26/95 at approximately 0130 hours0.0015 days <br />0.0361 hours <br />2.149471e-4 weeks <br />4.9465e-5 months <br />, with Unit 2 at 100% power and Unit 3 at approximately 70% power, during the performance of a Surveillance Test (ST),
the E-3 D/G Output Rreaker (E-32) tripped open while the operator was attempting to increase load on the unit. Troubleshooting revealed that the E-3 D/G Motor Operated Potentiometer (MOP), used for manually increasing load on the D/G during testing activities, had a dead spot. This dead spot on the potentiometer i
affected the E-3 D/G controller output signal thus causing the fuel racks to close and the D/G Output Breaker to trip open. At approximately 2312 hours0.0268 days <br />0.642 hours <br />0.00382 weeks <br />8.79716e-4 months <br />, the E-3 D/G was returned to an operable status following MOP replacement and successful D/G testing.
The E-2 and E-4 D/G MOPS were just replaced with a new type MOP during the recent D/G modification outages. The E-1 D/G MOP was just successfully used CCN 95-14068 ho 77 0
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U. S. Nuclear Regulatory Commission Pa'ge 2
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for testing on 7/25/95. In addition, the E-1 and E-3 D/G MOPS will be replaced with the new type MOP during future modification outages.
1 The E-3 D/G failure was classified as a non-valid failure using the guidance of RG 1.108, Revision 1,1977. Because this occurrence was classified as a non-valid.
failure, the current surveillance testing interval will remain at once per 31 days which is in conformance with RG 1.108, Revision 1, Section C.2.d.
During this event,- the E-3 D/G was unavailable for operation approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. The MOP is used for testing purposes only so that part of the logic which
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contains the MOP is normally bypassed on a D/G automatic start signal.-
Therefore, the MOP failure would not have prevented tha D/G from performing its safety function. In addition, the remaining D/Gs were operable and would have l
provided adequate AC power to safety related loads in the event of an actual loss of offsite power.
If you have any questions or require additional information, please do not hesitate to contact us.
i 1
Sincerely, l
1 GDE/GAJ:gaj cc:
R. A. Burricelli, Public Service Electric & Gas R. R. Janati, Commonwealth of Pennsylvania T. T. Martin, US NRC,~ Region I R. l. McLean, State of Maryland W. L Schmidt, US NRC Senior Resident inspector H. C. Schwemm, Atlantic Electric
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.l A. F. Kirby lil, DelMarVa I
CCN 95-14068 1
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