ML13324A735
| ML13324A735 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/15/1985 |
| From: | Morgan H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 8510220152 | |
| Download: ML13324A735 (2) | |
Text
Southern California Edison Company SAN ONOFRE NUCLEAR GENERATING STATION P. 0. BOX 128 SAN CLEMENTE, CALIFORNIA 92672 H.E.MORGAN TELEPHONE STATION MANAGER 1714) 368.6241 October 15, 1985 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. J. B. Martin, Regional Administrator
Dear Sir:
Subject:
Docket No. 50-206 Special Report -
Revision 1 San Onofre Nuclear Generating Station, Unit 1
Reference:
Special Report, H. E. Morgan (SCE) to J. B. Martin (NRC),
Same Subject, dated August 28, 1985 Pursuant to Section 6.9.3.f of Appendix A, Technical Specifications to Provisional Operating License No. DPR-13 for San Onofre Unit 1, the reference provided the required Special Report for inoperable radiation monitoring instrumentation.
On August 14, 1985, at 0925 with Unit 1 at 93% power, the High Range West Main Steam Line Radiation Monitor R-1258B failed low and was removed from service.
The preplanned alternate method of monitoring was initiated at 1311 in accordance with Limiting Condition for Operation (LCO) 3.5.10, Action Statement 27.
The Low Range West Main Steam Line Radiation Monitor as well as both High and Low Range East Main Steam Line Radiation Monitors have remained operable. An investigation into the cause of failure and performance of corrective actions is ongoing. The cause of instrument failure has been identified to be associated with a ground loop and/or AC noise induced int coaxial detector input/output cables.
The following corrective actions are to be accomplished and monitoC 4R-125' returned to service by November 1, 1985.
8510220152 851015 PDR ADOCK 05000206 S
Mr. J. B. Martin
-2
- 1. The 50-pin I/0 connector in the NIM bin will be replaced with an identical connector.
- 2.
The present grounding and shielding scheme will be corrected to eliminate ground loops.
Neither the health and safety of plant personnel nor the health and safety of the public was affected by this event. If you require additional information, please so advise.
Sincerely, cc:
F. R. Huey (USNRC Senior Resident Inspector, Units 1, 2 and 3)
U. S. Nuclear Regulatory Commission Document Control Desk Institute of Nuclear Power Operations (INPO)