ML20086H636
| ML20086H636 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/07/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| References | |
| AO-76-36, NUDOCS 8401190496 | |
| Download: ML20086H636 (2) | |
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PHILADEI5HIA ELECTRIC COMPANY
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2301 MARKET STREET
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NNb or. A. Giambusso Director Division of Reactor Licensing Office of Nuclear Reactor Regulations United States Nuclear Regulatory Coninission Washington, DC 20555
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence'was reported to Mr. Paul E. Nelson, Region 1, Office of Inspection and Enforcement, United States Nuc1 car Regulatory Commission on June 28, 1975 Written notification was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, United States Nuclear Regulatory Commission on June 30, 1975 In accordance with Section 6.7 2.A of the Technical Specifications, Appendix l
A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following occurrence is being submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-56 Technical Specification
Reference:
3 9.A.2 Report No.:
50-278-75-36 Report Date:
July 7, 1975 Occurrence Date:
June 27,1975 Facility:
Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:
Failure of the E-1 diesel breaker to the Unit 3 cmergency bus to close.
Conditions Prior to Occurrence:
Unit 3 at 50% power.
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Description of Occurrence:
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During an electrical switching operation in preparation for de-energizing of an off site power source, E-13 diesel breaker f ailed to close when requested by a switch in the control room. This breaker supplies energy from the diesel aenerator to the Unit 3 cmergency bus E-13..
8401190496 750707 PDR ADOCK 05000278 pO3 S
PDR 3
Mr. A. Giambusso 50-278-75-36 July 7,1975 Page 2 t
i 0esignation of Apparent Cause of Occurrence:
A linkage in the breaker cubicle cicvator mechanism cell switch was found to be bent.
Analysis of Occurrence:
This f ailure would have prevented the E-1 dicsci from supplying energy to the Unit 3 E-13 emergency bus under a loss of power situation.
A plant safety analysis requires only 3 operabic dicscis to accomplish a safe shutdown.
Immediately after this occurrence, all other diesel breakers were tested and found to be operational.
This failure, there-fore, has minimal safety significance.
Corrective Action:
The subject breaker was racked out and the clevator mechanism
- cell switch arm was straightened and the cell switch adjusted. The breaker was reinstalled and tested successfully. All other diesel breakers were successfully tested. A review of the surveillance test-s ing procedure for the dicscis has been accomplished. Revi sions are being made such that each of the diesel breakers will be operated every other week. The revised surveillance procedure should be issued prior j
to August 1, 1975 t.
Failure Data:
None.
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Very truly yours,
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.k H. J
'oo,ncy Ass Gen' t Superintendent Generation Division cc:
Mr. J. P. O'Reilly Director, Region 1 Office of Inspection and Enforcement United States Nucicar Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 m
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