05000361/LER-1982-151, Forwards LER 82-151/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-151/03L-0.Detailed Event Analysis Submitted

ML20064H909
Person / Time
Site:	San Onofre
Issue date:	12/28/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20064H911	List: 05000361/LER-1982-151, Forwards LER 82-151/03L-0.Detailed Event Analysis Submitted 05000361/LER-1982-151-03, /03L-0:on 821128,while Performing Monthly Channel Check Surveillance,Temp Indication TI-0111BX for Reactor Coolant Hot Leg Read More than 48 F Lower than TI-0911X1. Caused by Setpoint Drift.Indicator Recalibr
References
NUDOCS 8301170458
Download: ML20064H909 (2)

LER-1982-151, Forwards LER 82-151/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3611982151R00 - NRC Website

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Southern California Edison Company S AN ONOFRE NUCLE AR GENER A TING S T A TION

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~ TELEPHONE December 28, 1982

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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.82-151 San Onofre Nuclear Generating Station, Unit 2 This submittal is in accordance with the reporting requirements of Section 6.9.1.13b of Appendix A to Facility Operating License NPF-10.

It describes a reportable occurrence involving Limiting Condition for Operation (LCO) 3.3.3.5 associated with Remote Shutdown Instrumentation.

A completed copy of LER 82-151 is enclosed.

While in Mode 3, at 1100 on November 28, 1982, the monthly channel check surveillance in accordance with procedure S023-3-3.28 was in progress.

Indicator TI-OlllBX for reactor coolant hot leg temperature was observed to be reading more than 48 F lower than similar temperature indicator TI-0911 X1. Since TI-OlllBX is located on the Remote Shutdown Panel and only connected to its respective temperature element during use of the Remote Shutdown Panel or surveillance, it was suspected of having fallen out of calibration. TI-OlllBX was declared inoperable and LC0 3.3.3.5 Action statement a was invoked which allows operations to continue for up to seven days prior to restoring the channel to operable stt.tus.

Subsequent investigation revealed that TI-OlllBX had fallen out of calibration since it is not normally connected to its respective temper-ature element TE-OlllXl. Temperature Element TE-OlllX1 provides the hot leg reactor coolant temperature inputs to both indicators TI-0111 AX located in the Control Room (continuous indication) and TI-0111BX located on the Remote Shutdown panel (indication only when operating from this panel).

Therefore, TI-OlllBX normally reads off scale high (infinite potential) and falls out of calibration. The inoperable indicator was recalibrated and declared operable in accordance with procedure S023 3.28 at 1050 on December 2,1982.

8301170458 821228 gDRADOCK 05000361 PDR Q -2k 82-470

Mr. R. H. Engelken December 28, 1982 As corrective action to prevent recurrence, a Design Change Package (DCP) has been initiated to install a resistor in the circuitry for TI-OlllBX to maintain the indication at midscale when temperature element TE-OlllX1 is not connected to the indicator. This DCP will also correct a similar design problem in Unit 3.

Other indicators on the Remote Shutdown Panels were reviewed and found not to be susceptible to a similar problem.

Since the indicator was returned to operable status within the allowable time constraints, there was no impact on plant operation or the health and safety of plant personnel or the public, If there are any questions regarding the above, please contact me.

1 Sincerely, l

Y NL'hV7 Enclosure: LER 82-151 cc:

A. E. Chaffee (USNRC Resident Inspector, San Onofre Unit 2) a U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information and Program Control Institute of Nuclear Power Operations l

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