ML20207T277
| ML20207T277 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 03/06/1987 |
| From: | Querio R COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| BYRON-87-0295, BYRON-87-295, NUDOCS 8703230387 | |
| Download: ML20207T277 (2) | |
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B RON 87-0295 FILE:
2.7.400
,' Mr. James G. Keppler Regional Administrator Region 3 U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Sir:
This report is submitted in cecordance with Byron Station Unit 1 Operating License NPF-37 Appendix A, Technical Specification 4.8.1.1.3, reporting of Diesel Generator Failures.
This report addresses one valid test and failure experienced on the 1 A Diesel Generator.
The criteria to determine valid tests and failures is in accordance with Section C.2.e of Regulatory Guide 1.108.
On February 10,1987 the 1 A Diesel Generator was started per the monthly operability surveillance, IBOS 8.1.1.2.a-1. Per Technical Specification 4.8.1.1.2 the Diesel Generators are required to reach rated speed, voltage, and frequency within ten seconds of the start signal. The 1 A Diesel Generator required 15 seconds to reach rated conditions. Following the start, Limiting Condition for Operation Action Requirement (LCOAR) 8.1.1-la was initiated for one Diesel Generator inoperable.
At 0644 the 1 A Diesel Generator was restarted and reached rated conditions in 6 seconds. At 0912 LCOAR 8.1.1-la for one Diesel Generator inoperable was exited.
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Page 2 The intermedia'te cause for the slow start of the 1 A Diesel Generator was an inadequate prime in the fuel oil supply line. The root cause for this occurrence was the failure of a check valve, located between the engine mounted day tank and the supply day tank, fuel oil can gravity feed back to the supply day tank in the event that the check valve fails to seat. An additional soft seat check valve is being installed between the engine day tank and the supply day tank during the current Unit I refueling outage to prevent reoccurrence of this failure. This modification has been installed on the Unit 2 Diesel Generators. No slow starts have occurred on the Unit 2 engines since implementation of this modification.
The 1 A Diesel Generator was inoperable for four hours following this valid test and failure. This failure is the first failure within the last twenty valid tests, therefore the testing frequency of the 1 A Diesel Generator will remain on a monthly basis.
R. E. Querio -
Station hfanager Byron Nuclear Power Station REQ /h151R/bf cc:
J. Ilinds, NRC Resident Inspector U.S. NRC Document Control Desk, Washington, D.C.
INPO Record Center CECO Distribution List
- 51. Robert J. Cook 4
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