ML20085F859

AO AO-21-74:on 741008,diesel Generator 1-1 Failed to Start. Caused by Use of Only One air-start Motor.Both air-start Motors Will Be Used in Future

ML20085F859
Person / Time
Site:	Palisades
Issue date:	10/18/1974
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085F584	List: ML20085F582 ML20085F859 ML20085F867
References
AO-21-74, NUDOCS 8308230522
Download: ML20085F859 (3)

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c b% 1'j la o.n .. o,..ce.- 212 We=st Machigan Avenue. Jackson, Mic higan 49201. Area Code 517 788-0550 October 18, 1974 Directorate of Licensing Re: Docket 50-255 US Atomic Energy Commission License DPR-20 Washington, DC 205h5 ' Palisades Plant - A0-21-74 Gentlemen:

Attached is Abnormal Occurrence Report A0-21-74 which covers the failure of one of the two diesel generator air-starting motors on diesel Generator 1-1. This failure occurred during a test; and, since only one air motor was being used, resulted in a s failure of the diesel generator to start within the required 10 seconds. A subsequent test demonstrated that the generator would start within the required time period.

Yours very truly, Ralph B. Sewell (Signed)

DAB /mel Ralph B. Sevell Nuclear Licensing Administrator CC: JGKeppler, USAEC

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ABNORMAL OCCURRENCE REPORT Palisades Plant

1. Report Number: A0-21-Th, Docket 50-255

2. a. Report Date: October 18, 1974.

b. Occurrence Date: October 8, 1974.

3. Facility: Palisades Plant, Covert, Michigan.

h. Identification of Occurrence: Failure to start of diesel Generator 1-1 due to air-start motor control problems.

5. Conditions Prior to Occurrence: Plant operating at approximately 25% power level.

6. Description of Occurrence: The unit was test-operated in accordance with monthly test procedure which utilizes only one of two air-start motors. The first attempt resulted in failure to start due to failure of the air-start motor controls. The other air-start motor was placed in service and the diesel generator started in eleven seconds (one second over limit).

7 Designation of Apparent Cause of Occurrence: The unit exceeded the ten-second starting time by a very small margin, because only one air-start motcr was used. The practice of using only one air-start motor during monthly testing had been used in the past to ensure operability of both air motors by testing them independently. This practice has resulted in routine engine start times of nine to ten seconds which is very close to the Technical Specifications limit.

In this particular instance, the starting time did exceed the ten-second Technical Specifications limit.

8. Analysis of Occurrence: The failure of the air-start motor was found to be caused by failed contacts in a relay operating the air supply solenoid valve. The diesel was restarted a second time using only one air-start motor and started within ten seconds. The variance of one second, from ten to eleven, in starting time using only one air-start motor, is felt to be a realistic and expected i

result. The use of both air-start motors will increase the unit

! acceleration, reduce starting time, and result in a much better margin of compliance with the Technical Specifications.

9 Corrective Action: This item has been reviewed by the Plant Reviev Committee (PRC) and is considered closed in that the problem has l been investigated, repaired and the unit test started within the

! required ten-second time limit. The PRC also recommended that the 1

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9 Corrective Action (Contd) test procedure be modified to include the use of both air-start motors as this is how the system would operate in an emergency condition. The failure of the diesel to start within ten seconds, using one air-start motor, is not considered an abnormal occur-rence. Diesel starts using both starting motors within the required starting time meet the Technical Specifications requirements.

10. Failure Data:

a. There are no records of similar previous failures.

b. The relays are Westinghouse Control Relay, Catalog BFD 66, Style 47E8409, 300 Volt AC,10 ' Amp, Poles 6 NO and 6 NC.

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