ML19317F359

RO 270/77-09:on 770505,2A Reactor Bldg Emergency Cooling Unit Failed to Start in Low Speed.Caused by Bent Contact on B Finger of 2A Reactor Bldg Cooling Unit High Speed Starter.Contact Repaired

ML19317F359
Person / Time
Site:	Oconee
Issue date:	06/06/1977
From:	DUKE POWER CO.
To:
Shared Package
ML19317F350	List: ML19317F349 ML19317F359
References
RO-270-77-09, RO-270-77-9, NUDOCS 8001140612
Download: ML19317F359 (1)

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7 iReport No.: LR0 270/77 T b; ,<

LReportrDate: 7Junei6, 1977-- _

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J:Occurrenc'e'Date: .May 5,(1977

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Fac11'Ity: 10conee. Unit:2,: Seneca,; South Carolina 1 ,

' Identification of; Occurrence: : Reactor-. Building cooling unit inoperable due to failed magnetic.contactor Conditilons Prior: toJ 0 ccurrence: Unit at 100 percent full power Description of Occurrence:

. .OnMayi5,l1977;NuringtheperformanceofaReactorBuildingemergencycool-Lingand~ isolation logic on-line' test. the "2A" Reactor Building cooling unit s

'(RBCU)' failed'to start in low speed.

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Investigation revealed that a high

~ speed.. starter? finger'. contact on the unit was . inoperable. The contact was repaired and:the."2A" RBCU'was returned to service'within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of'the

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7 Apparent Chuse of-' Occurrence:-

1 This occurrence was caused by a bent contact.on the."B" finger of the "2A" ~

, :RBCU high' speed starter. This contact must be made for:the motor to start- ~

in~1owispeeda

" Analysis'of Occurrence:

UF or : the 'perio'd ~of time;'during-which the ."2A", RBCU was out of service, both -

.-Reactor: BuildingJspray system and ~ the two remaining Reactor' Building cooling

units!were operable as required 'byf oconee Technical' Specification 3.3.6(b).

-lThese. systems haveyful1~ heat. removal capability in'the event of-an ES -

? actuationLand,ithereforci 'it. is. concluded that -the health and safety of

. the. public were. not affected by this incident.'

LCorrective Action:

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The high1 speed : starter finger contact was repaired and the "2A" RBCU was t

iverified ' operable.QThel Unit 2 RBCU's -are scheduled for preventive mainte-inancelinspections'during(the-Unit:2 refueling outage which began May 28, j ,

Sl977J:1Specialfattention-willibe placed.on contacts..oflthis type. '. Periodic.

. inspection of these contactors will'be performed at refueling outageaf

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