ML13308B502
| ML13308B502 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/12/1975 |
| From: | Fogarty D SOUTHERN CALIFORNIA EDISON CO. |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8103060640 | |
| Download: ML13308B502 (2) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE DAVID J. FOGARTY ROSEMEAD, CALIFORNIA 91770 TELEPHONE VICE PRESIDENT 213-572-2796 September 12, 1975 "S Mr. Angelo Giambusso, Director6"4 Division of Reactor Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Code:
BETH:042 Washington, D. C.
20545 Docket No. 50-206 San Onofre Unit 1 No. 1 Diesel Generator
Dear Sir:
This report describes an incident experienced at the San Onofre Nuclear Generating Station concerning the No. 1 diesel generator.
In accordance with Station-Order S-0-19 which outlines the testing of auxiliary protective equipment, the two diesel generators are tested semi-annually.
These tests are in addition to the weekly and refueling interval testing required by Technical Specifications 4.4 A and B. The semi-annual test requires that both diesel generators be operated at rated load of 600 KW for one hour.
During this test conducted on August 12, 1975, the No. 1 diesel generator tripped because of high cooling water temperature after 35 minutes of operation.
The diesel cooling system consists of a water to air radiator type heat exchanger, an engine driven water circulating pump and water jackets in the engine block. The water jacket is equipped with thermostats and a high temperature alarm which is received at a local panel and a common master alarm in the Control Room.
During the course of the investigation, it was determined that the radiator heat exchanger air passages were blocked with corroded portions of the radiator cooling fins.
This was unexpected since the radiator w cleaned during the fourth refueling outage.
-3 1012"
-2 To correct the condition, the radiator was cleaned and the No. 1 diesel generator was operated at rated load for one hour without the cooling water temperature exceeding the alarm set point. To prevent a recurrence of this situation, the radiators on both No.
1 and No.
2 diesels will be inspected and cleaned on more freauent intervals.
To ensure that Technical Specification requirements were satisfied during the period the No. 1 diesel generator was out of service, operability of the No. 2 diesel generator was demonstrated by completion of a partial load test.
Sincerely, cc:
Director, Region V Office of Inspection & Enforcement