ML20090D790

AO-50-219/75-05:on 750306,during Monthly Surveillance Test, Containment Spray Pump 51A Failed to Start When Subjected to Simulated Signals.Caused by Breaker Trip Bar Failing to Reset After Previous Breaker Trip.Trip Bar Bushings Cleaned

ML20090D790
Person / Time
Site:	Oyster Creek
Issue date:	03/13/1975
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A Office of Nuclear Reactor Regulation
References
AO-50-219-75-05, AO-50-219-75-5, NUDOCS 8303020374
Download: ML20090D790 (3)

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?n,i Jersey Central Power & Light Com i MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07960

• 201-539-6111 uswanu w rue Pubhc Utiht.es Corporation General

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srs en March 13, 1975 e

Mr. A. Giambusso Director, Division of Reactor Licensing B.

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Office of Nuclear Reactor Regulation -

United States Nuclear Regulatory Commission b 4;Nj[j%r Cff; Washington, D. C. 20545 W[u'ty y q los

Dear Mr. Giambusso:

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Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/75-5 The purpose of this letter is to forward to you the attached Konormai Occurrence keport in cumpliance with paragraph 6.6.2.a of dm Technical Specifications.

Enclosed are forty copies of this submittal.

Very truly yours,

& fA I Donald A. Rass Manager, Generating Staticns-Nuclear Pk Enclosures cc: Mr. J. P. O'Reilly, Director Office of Inspection and Enforcement, Region 1 i

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• ol 11 I 8303020374 750313 j' 'O '[ J et PDR ADOCK 05000219 --

S PDR COPY SENT ltEGION

U U 7p Jersey Central Power & Light Company W(f MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07%0

• 201-539-6111

.,...r o senerai g'{", Public Utih*A corporation SFSfim OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence '

Report No. 50-219/75-5 Report Date March 13,1975 Occurrence Date March 6, 1975 Identification of Occurrence Failure of containment spray pump 51A to start when called upon to do so.

This cvent is considered to be an abnormal occurrence as defined in the Technical Lpecifications, paragraph 1.15D.

Conditions Prior to Occurrence The plant was operating as steady-state power with major parameters as follows:

Power: Reactor,1895 'Mt Electric, 665 MWe 4

Flow Recirculation, 15.8 x 10 8PM Feedwater, 7.67 x 10 6 lb/hr Stack Gas: 29,600 pei/sec Description of Occurrence It was observed on Thursday, March 6, 1975, at 0950, during the monthly surveillance test of the containment spray systen that containment spray pump 51 A failed to start in the automatic mode when subjected to simulated low-low reactor water level and high drywell pressure signals. The " pump failure" alarm initiated approximately 64 seconds after the start signal was applied. An operability check was performed on the redundant System 1

. 4-m Abnormal Occurr U Report No. 50-219/75-5 O PeR 2 containment spray pump 51B, and containment spray pump 51A was then removed from service to investigate the cause of the failure.

Apparent Cause of 0::currence

. The occurrence was caused by the breaker trip bar failing to reset after a previous trip of the breaker.

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Analysis of Occurrence

'Ihe only significance associated with the failure of 31A to start is in a loss of system redundancy. Ilad conditions arisen requiring containment spray, pump SIC would have started automatically and performed the contain-ment heat removal function. In addition, the manually initiated backup pump 51B for System I was checked and could have been initiated. The containment heat removal function can be adequately supplied by a single containment spray pump.

C_o_rrective Action The failure monitor installed as a result of a similar occurrence on October 21, 1974 functioned during this event and the information obtained showed that the logic circuit was operating properly. The breaker was then manually i

operated by slow closing at which time it was recognized that the breaker trip bar was not resetting properly. -The trip bar bushings were cleaned and lubricated with light machine oil and then satisfactorily retested.

As added assurance against improper automatic operation of containment spray pump 51A, the circuit breakers for containment spray pumps 51A and 51B (manual pump) were interchanged af ter ensuring the proper operation of the trip bar on the SIB breaker. The trip bar and bushings on breakers associated with all core spray, containment spray, and CRD hydraulic pumps will be inspected and more specific attention will be directed to the trip bar and bushings during the yearly preventative maintenance check of these breakers in order to prevent a recurrence of this failure. The failure monitor will be connected to containment spray pump 51A prior to testing until the spring refueling outage as added assurance that no further problem exists in the pump logic circuit; Failure Data Previous abnormal occurrences involving the containmeat spray system:

,, 1. Abnormal Occurrence Report No. 50-219/72-12 -

2. Abnormal Occurrence Report No. 50-219/73-12 i 3. Abnormal Occurrence Report No. 50-219/74-55

4. Abnormal Occurrence Report No. 50-219/75-3

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