ML13324A924
| ML13324A924 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/21/1986 |
| From: | Medford M Southern California Edison Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8607240031 | |
| Download: ML13324A924 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M. 0. MEDFORD TELEPHONE MANAGER, NUCLEAR LICENSING July 21, 1986 (818) 302-1749 Director, Office of Nuclear Reactor Regulation Attention: G. E. Lear, Director PWR Project Directorate No. 1 U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Supplemental Inspection Report on Emergency Diesel Generator No. 1 San Onofre Nuclear Generating Station Unit 1
References:
A) Letter, M. 0. Medford (SCE) to G. E. Lear (NRC), dated May 19, 1986, Inspection Report on Emergency Diesel Generator No. 1 B) Letter, M. 0. Medford (SCE) to G. E. Lear (NRC), dated June 20, 1986, Inspection Report on Emergency Diesel Generator No. 2 By References A and B, Southern California Edison transmitted for your review the results of inspections performed on Emergency Diesel Generators (DG's) No. 1 and No. 2 at the San Onofre Nuclear Generating Station, Unit 1, during the 1985-86 refueling outage.
Reference A reported that, in the case of DG No. 1, only one turbocharger was inspected in accordance with the Transamerica Delaval, Inc.
diesel generator owners group recommendations and the results were favorable.
Reference B reported that, in the case of DG No. 2, all four turbochargers were inspected and corrective actions were taken, as needed. However, the turbochargers were operable as found.
This letter is to inform you that after DG No. 2 had been inspected, reassembled and returned to service, the two rear turbochargers of DG No. 1 were inspected. These rear turbochargers had not been inspected, overhauled or replaced since their original installation in 1976-77.
One rear turbocharger passed its inspection and was reinstalled and load-tested successfully. The inspection consisted of a visual examination of the turbocharger internals and a magnetic particle examination of the shaft thrust bearing faces.
Visual examination of the other turbocharger indicated thrust 8607240031 860721 PDR ADOCK 05000206 0
Mr. G.
July 21, 1986 bearing wear. A spare turbocharger was installed in its place for purposes of returning DG No. 1 to service. This turbocharger was then sent to the manufacturer (Elliott Company) for rework. Subsequent dye penetrant examination at the manufacturer's service center revealed cracks in the shaft thrust bearing collar.
The probable cause of the thrust bearing wear and shaft thrust collar cracks is considered to be insufficient bearing lubrication during the early years of diesel operation (1977-1982).
However, this service condition was corrected in 1982 by initiating pre-lubricated test starts.
If you have any questions, please call me.
Very truly yours, cc:
R. Dudley, NRC/NRR San Onofre Unit 1 Project Manager F. R. Huey, NRC Senior Resident Inspector, Units 1, 2 and 3 J. B. Martin, NRC Region V, Regional Administrator D. E. Broeils, Duke Power Co., TDI DG Owners Group