ML20090D060

AO 75-29:on 751027,torus Drywell Vacuum Breakers Alarm Sys II Failed to Annunciate When Vacuum Breaker V-26-8 Opened. Caused by Sticking Microswitch

ML20090D060
Person / Time
Site:	Oyster Creek
Issue date:	11/06/1975
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Boyd R Office of Nuclear Reactor Regulation
Shared Package
ML20090D063	List: ML20090D060 ML20090D076
References
A-751106, AO-75-29, GN-75-039, GN-75-39, NUDOCS 8302240043
Download: ML20090D060 (3)

Text

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f p% il Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07960

• 201-539-6111 -

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- General j~ Pubhc Utihties Corporation

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b OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731 Abnormal Occurrence Report No. 50-219/75-29

, Report Date November 6,1975 Occurrence Date October 27, 1975 Identification of Occurrence Failure of torus to drywell vacuum breakers alarm system II to annunciate when vacuum breaker V-26-8 was opened for an operability test. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15.D.

Conditions Prior to Occurrence i The plant was at steady state power with the following major parameters:

Power: Core, 1301 FMt Electric, 426 MWe Flow: Recirculation, 4.8 x 104 lb/hr Feedwater, 5 x 10 6 lb/hr Reactor Pressure: 1020 psig Stack Gas: 5500 pCi/sec Description of Occurrence At approximately 1015 on October 27, 1975, during a routine operability test of the torus to drywell vacuum breakers, alarm system II failed to annunciate in the control room when V-26-8 was opened. Subsequent operations of V-26-8 showed alarm system II to be operabic.

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GN-75-039' d6 O

Abnormal Occurrence Report No. 50-219/75-29 O Page 2 i

Apparent Cause of Occurrence Component malfunction is the cause of this occurrence, but the sp;cific nature

of the malfunction could not be identified (see below).

- Analysis of Occurrence j

The safety significance of this event is considered to be minimal. The alarm systems for the torus to drywell vacuum breakers are to insure vacuum breaker availability in the event of an accident condition. The failure of system II to be operable for V-26-8 resulted only in loss of redundancy for the alarm function. Ilad V-26-8 been open during operation, system I would have performed the necessary alarm function.

I Corrective Action l

} The electrical maintenance department conducted an investigation to determine 1 . the cause of the failure. The operability test was then conducted for four

' consecutive days following the event,and the failure could not be repeated.

! At this time, it is postulated that a sticking microswitch for vacuum breaker

! valve V-26-9 was the cause of the failure. In further effort to determine the i cause, a plant electrician will be availabic during the next surveillance test to check the operation of the valve microswitch.

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Jersey Central Power & Light Company &

MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-539-6111 nn n, n r=,

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General {]. {", Public Utiteties Corporation SYST5 5 November 6, 1975 o O

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A Mr. R. Boyd, Acting Director t $%o8 q g$'

Chi p Division of Reactor Licensing ~2, #hf.0 lg%,A g g jy Office of Nuclear Reactor Regulation g ., y United. States Nucicar Regulatory Commission s Washington, D. C. 20555 -

Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/75-29 The purpose of this letter is to forward to you the attached abnormal occurrence report in compliance with paragraph 6.6.2.a of the Technical Specifications.

ery truly yours, .

p ecd i I

Donald A. Ross, Manager I

sla w Generating Stations-Nuclear es Enclosures cc: Mr. J. P. O'Reilly, Director Office of Inspection and Enforcement, Region 1 e

12836 COPY SEYP REGION