ML20140E358
| ML20140E358 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/27/1984 |
| From: | Haynes J SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| NUDOCS 8501100796 | |
| Download: ML20140E358 (2) | |
Text
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Southern California Edison Company
$6 SAN ONOFRE NUCLE AR GENER A TING ST ATION P.O. BOK 128 5 AN CLEMENTE. C ALIFORNI A 92672 J. G. H A YN ES vetapwOnE "o""a"^*'"
Decenber 27, 1984 U.S. Nuclear Regulatory Commission Document Control Desk
' Washington, D.C.
20555
Subject:
Docket No. 50-361 Licensee Event Report No. 84-002-Licensee Event Report No.84-023 San Onofre Nuclear Generating Station, Units 2 and 3
References:
(1)
Letter, J. G. Haynes (SCE) to USNRC Document Control Desk, dated February 28,- 1984; Licensee Event Report No.84-002 (2)
Letter, J. G. Haynes (SCE) to USNRC Document Control Desk, dat'ed June 21, 1984; Licensee Event Report No.84-023 (3) letter,.J. G. Haynes (SCE) to USNRC Document Control Desk, dated August 30, 1984; Licensee Event Report No.84-002, Revision 1 Reference (1) provided 'the required 30-day Licensee Event Report (LER) for occurrences involving the spurious actuation of the Containment Purge Isolation System (CPIS) which was apparently due to a noise spike. Reference (2) provided the required 30-day LER for occurrences involving the spurious actuation of the Control Room Isolation System (CRIS), also apparently due to a noise spike.
Reference (3) stated that LER 84-002, Revision 1,=and LER 84-023, Revision 1, would be submitted by December 31, 1984, at the conclusion of our investigation of the cause of the spurious actuations and identification of corrective act?on.
As. stated in. Reference (3), we retained a contractor, specializing in noise reduction, who would evaluate monitor performance data and assist us in determining the cause and corrective actions.
However, the results to date are inconclusive.
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8501100796 041227 PDR ADOCK 05000361 g l~
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L U.S. Nuclear Regulatory Commision -Investigation has determined that the most probable single cause of the actuations was ground current spikes traveling to the monitors through the ground system. The ground current spikes were probably caused by switching transients on heavy current equipment.
Testing and evaluation of the ground system will be required before problem identification and corrective action can be determined.
We are therefore continuing our review and investigation. We will submit revisions to the subject Licensee Event Reports at the conclusion of this investigation.
Sincerel,
Yh M M A^nf
/
F. R. Huey (USNRC Senior Resident Inspector, Units 1, 2 and 3) cc:
J. P. Stewart (USNRC Resident Inspector, Units 2 and 3)
J. B. Martin (Regional Administrator, USNRC Region V)
Institute of-Nuclear Power Operations (INPO) 1
.