05000361/LER-1982-171, Forwards LER 82-171/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-171/03L-0.Detailed Event Analysis Submitted

ML20064L459
Person / Time
Site:	San Onofre
Issue date:	01/28/1983
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20064L463	List: 05000361/LER-1982-171, Forwards LER 82-171/03L-0.Detailed Event Analysis Submitted 05000361/LER-1982-171-03, /03L-0:on 821231,operator Insp Revealed Loss of Position Indication for Control Element Assembly 79 as Indicated by Control Element Assembly Calculator 1.Caused by Faulty Reed Switch.Reed Switch Replaced
References
NUDOCS 8302150276
Download: ML20064L459 (2)

LER-1982-171, Forwards LER 82-171/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3611982171R00 - NRC Website

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January 28, 1983 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:

Mr. R. H. Engelken, Regional Administrator

Dear Sir:

Subject: Docket No. 50-361 30-Day Report Licensee Event Report No.82-171 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Section S.9.1.13.b of Appendix A Technical Specifications to Facility Operating License NPF-10 for San Onofre Unit 2, this submittal provides the required 30-day written report and a copy of Licensee Event Report (LZR) for an occurrence involving Limiting Condition for Operation (LCO) 3.3.1 associated with the Reactor Protection System (RPS).

On December 31, 1982, with the plant in Mode 2, operator inspection revealed a loss of position indication for Control Element Assembly (CEA) 79 (Regulating Group 2) as indicated by Control Element Assembly Calculator (CEAC) 1.

CEAC 1 was declared inoperable at 0830 and the appropriate Action Statement associated with LC0 3.3.1 was invoked. As required by this Action Statement (Table 3.3-1, Action 6a), each CEA was immediately verified to be within 7 inches of all other CEA's in its group via redundant position indications from CEAC 2 and the CEA pulse counting position indicator. Additionally, as required, this verification was updated every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Subsequent investigation revealed that loss of position indicatinn for CEA 79 was attributable to a faulty reed switch associated with the Upper Electrical Limit (UEL). This reed switch is continuously actuated when the CEA is fully withdrawn as in this case. The reed switch was replaced and CEAC 1 was returned to operable status in accordance with Procedure S023-3-3.25 at 2000 on December 31, 1982. This was an isolated occurence and no further corrective action is planned. Enclosed LER 82-171 addresses this event.

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R. H. Engelken January 28, 1983 There was no impact on plant operation or the health and safety of plant personnel or the public associated with this event.

If there are any questions regarding the above, please contact me.

Sincerely, Enclosure: LER 82-171 A. E. Chaffee (USNRC Resident Inspector, San Onofre Units 2 & 3) cc:

R. J. Pate (USNRC Resident Inspector, San Onofre Units 2 & 3)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information and Progam Control Institute of Nuclear Power Operations