ML19294A505
| ML19294A505 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/29/1978 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19294A502 | List: |
| References | |
| NUDOCS 7812070213 | |
| Download: ML19294A505 (2) | |
Text
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PHILADELPHI A ELECTRIC COM PANY 2301 M ARKET STREET PHILADELPill A. PA.19101 1215)041 4000 November 29, 1978 Mr. Boyce 11. Grier, Director Of fice of Inspection and Enforcement Region I United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Grier :
SUBJECT:
Licensee Event Report s'arrative Description
Reference:
Docket No. 50-277 Report No:
LER 78-041/1T-1 Report Date:
November 29, 1978 Occurrence Date:
October 10, 1978 Facility:
Peach Bottom Atomic Power Station Unit 2 R.D. 1, Delta, PA 17314 Technical Specification Re ference:
Tabic 3.2.B, page 71, delineates the trip setting for the sequential loading relays to be 95% +07.,
-107, of rated voltage.
Description of the Event:
During a surveillance test, the 4KV emergency bus sequential loading relays were found to be outside of the calibration range specified by Technical Specifications.
Investigation determined that the setpoint span specified in the surveillance tests was inaccurate.
The relays were also set at the upper limit of the specified range which would allow even a small setpoint upward shift to place the relay outside the limit.
7812070213
Mr. Boyce H. Grier Page 2 November 29, 1978 LER 78-041/1T-1 Consequences of Event:
The sequentini loading relays which were found to be outside of the Tech Spec limit, load the emergency diesel generators in the event of a loss of power. The relays were found to be less than 1%
of range thus the diesel generators would have loaded at 96% rather out than 95% of rated voltage.
Safety implications are minimal since a diesel auto actuation and load acceptance test had been performed on both Unit 2 and Unit 3 during the previous refueling outage after relay calibra tion.
Cause of Event:
The cause of this event is attributed to an error in deter-mining the setpoint and calibration span specified in the surveillance test.
The surveillance test specified less than 0.1% above the Tech Spec limit of 95% of rated voltage.
Corrective Action:
All of the Unit 2 and Unit 3 sequential loading relays on the 4KV cmergency busses were recalibrated to the midrange of the span stated in the Technical Specifications.
The surveillance test for the relay calibration has been reviewed and the deficiency has been resolved.
Action to Prevent Recurrence:
No further actions are scheduled.
Yours truly, f
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M.,,J Cooney Guperintendent Generation Division /Neclear Attachment Direct < r, NRC - Of fice of Inspection & Enforcement cc:
Mr. Usrmar LL Heller, NRC - Of fice of Management & Program Analysis
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