ML13308B493
| ML13308B493 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/05/1976 |
| From: | Fogarty D SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 8103060549 | |
| Download: ML13308B493 (1) | |
Text
Southern California Edison C6mpany P. 0. BOX 800 2244 WALNUT GROVE AVENUE DAVID J. FOGARTY ROSEMEAD, CALIFORNIA 91770 TELEPHONE vce pR.siasNr 213-572-2796 August 5, 1976 U. S. Nuclear Regulatory Commission Region V Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, California 94596 Docket No. 50-206 Attention: R. H. Engelken, Director
Dear Sir:
This letter describes the failure of one of the excore axial offset monitoring channels at San Onofre Nuclear Generating Station Unit 1.
An operator, during his routine rounds, noticed the high voltage supply for channel 7 of the excore axial offset (EAO) monitoring system was reading abnormally low. Investigation into the cause of this low reading revealed a short to ground in the lower detector or in the cable leading from the lower detector to the instrumentation. Repair is not possible during reactor operation; therefore, channel 7 was declared out of commission June 1, 1976. This failure was determined to be a report able occurrence in accordance with section 6.9.2.b of the Technical Specifications on July 15, 1976.
In accordance with section 3.1l.c of the Technical Specifications, nuclear instrumentation channel currents are being logged every two hours and axial offset information is determined from these data. EAO channel 7 will be repaired during our next refueling outage.
Sincerely, cc: Director, NRC Office of Inspection and Enforcement Director, NRC Office of Management Information and Program Control 5OcDO47