05000361/LER-1982-072, Forwards LER 82-072/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-072/03L-0.Detailed Event Analysis Submitted

ML20064N295
Person / Time
Site:	San Onofre
Issue date:	08/20/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20064N299	List: 05000361/LER-1982-072, Forwards LER 82-072/03L-0.Detailed Event Analysis Submitted 05000361/LER-1982-072-03, /03L-0:on 820721,120-volt Ac Vital Bus 2Y03 de-energized from Associated Inverter W/Plant in Mode 4. Normal Offsite Power Available.Caused by Inadvertently Applied Ground.Bus re-energized
References
NUDOCS 8209080299
Download: ML20064N295 (2)

LER-1982-072, Forwards LER 82-072/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3611982072R00 - NRC Website

text

_ _ _ _ _ _ - _ _. _ - _ _

s J ECENES Southern California Edison Company 3 m 25 m it: 2gE S AN ONOFRE NUCLE AR GENER ATING S T A TION p.o. eOx saa s AN C LEMENT E. C A LIFORNI A 92672

.. + + i H. B. R AY TetrewoNe

$7 ATION M AN AGE R (7 4 4) 492.F FOO 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.82-072 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 condition involving Limiting Condition for Operation (LCO) 3.8.3.1 associated with Onsite Power Distribution Systems. A completed copy of LER 82-072 is enclosed.

While in Mode 4, at 1220 on July 21, 1982, 120 VAC Vital Bus 2Y03 was accidentally de-energized from its associated inverter and LCO 3.8.3.1 Action Statement b was initiated.

This Action Statement requires the de-energized bus to be:

(1) re-energized within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least Mode 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 5 v:lthin the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />; and (2) re-energized from its associated invertar within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least Mode 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 5 within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

The bus was immediately re-energized to its alternate power supply, Train A Bus 2B04.

Following removal of a ground, the bus was re-energized from its associated inverter at 1430 on July 21, 1982, thus fulfiIIing the requirements of the associated Action Statement.

8209080299 820820 PDR ADOCK 05000361 pQ S

PDR 62-JlW

e R. H. Engelken August 20, 1982 investigation into the cause revealed that the bus was accidentally de-energized due to an inadvertently applied instrument ground. This temporary ground was applied during equipment testing within Radiation Monitoring System panel 2L-103.

This event was an isolated occurrence and further corrective action is not deemed necessary.

Normal of fsite power was available throughout the event, hence there was no impact on health and safety of plant personnel or the public.

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

Sincerely, Wf J

Enclosure:

LER 82-072 cc:

A. E. Chaf fee (USNRC Resident inspector San Onof re, Unit 2)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Of fice of Management information and Program Control Institute of Nuclear Power Operations