05000312/LER-1981-047, Forwards LER 81-047/01T-0.Detailed Event Analysis Submitted

Forwards LER 81-047/01T-0.Detailed Event Analysis Submitted

ML20031G495
Person / Time
Site:	Rancho Seco
Issue date:	10/12/1981
From:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20031G496	List: 05000312/LER-1981-047, Forwards LER 81-047/01T-0.Detailed Event Analysis Submitted 05000312/LER-1981-047-01, /01E-0:on 810930,bus a Emergency Pressurizer Heater Bank 3 Operated Intermittently Due to Loose Wire. Caused by Misoriented Screw Washer.Washer re-oriented & Screw Tightened
References
NUDOCS 8110220484
Download: ML20031G495 (2)

LER-1981-047, Forwards LER 81-047/01T-0.Detailed Event Analysis Submitted

Event date:
Report date:
3121981047R00 - NRC Website

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$ SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 s street, box 15830, sacramento, California 95813[i(916) 452-3211 9

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c October 12,

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/ / [/ i fi"RIE'd I R H ENGELKEN, DIRECTOR s

l'/ h,.' c REGION V 0FFICE OF luSPECTION f, ENFORCEMENT 1650 MARIA LANE SUITE 210 Q@ o 9, *q'-. -- T, WALNUT CREEK CA 94596

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A DOCKET NO. 50-312 LlCENCE NC. DPR-54

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PEPORTABLE OCCURRENCE 81-47 h!

In accordance with Technical Specifications for Pancho Seco Unit 1, Section 6.9.4.l(i) and Regulatory Cuide 1.16, Pevision 4, Section C.2.a(9), the Sacramento tiunicipal Utility District is hereby submitting a follow up report to Reportable Occurrv ee 81-47, s.hich was discussed on October 2, 1981 with our on-site inspector and confirmed by let ter on October 5, 1981 As discussed in the District's October 5, 1981 letter, intermittent operation of Bank 43 of the Bus A Emergency Pressurizer Heaters was observed by operating personnel.

Scheme ti2C311 of drawing E203, sheet LSA, was used to t race the problem to a wi re loose under its terminal screw on relay LxA.

The wire was loose due to the locl:ng screw washer, which is rectangular shaped, beine rotated 90 around the screw.

This prevented the locking screw from being tightened down on the wire lug.

The washer was turned back to its proper orientat ion and the screw t ightene/.

This corrected the original problem.

Although there has been no indication that terminals on other relays of this type may have been improperly tightened, the following measures are being implemented to insure no further occurrences of this type:

a.

During the performance of electrical preventative maintenance procedures, all Square D Class 8501, Type G920, Series D-tiH relays encountered will be inspected for proper washer a l i e nrren t.

The procedure check lists will be chanced to include this iten.

This will be continued over the next year.

Ofbb AN ItECIPIC "YSTIM S E F.' l N G MChE THAN

.2 0.000 fN THt HEART OF Cit lIORNIA

R. H. Engelken ' October 12, 1981 b.

At the end of one year, approximately one half of all NCC's and switchgear in the plant will have been inspected under the preventative maintenance procedures. The results of the inspections for washer orientation will be reviewed.

I f no additional terminal washer misalignments are found, the District will consider the event an isolated situation.

If other problems are noted, further a-tion will be determined at that time.

A f.,llow up to this report will be issued in October of 1982, detailing the results of this inspection.

Since the plant was in cold shutdown, there were no plant transitents or power reductions associated with this occurrence.

In addition, the duration of the current shutdown was not ef fected by this event, i

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• fH i Y L e-L ohn Mattimoe Assistant General Manager and Chief Engineer cc:

ISE Washington (30)

MIPC (3)

INPO I

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