ML20085B416

Ro:On 720229,emergency Diesel Would Not Accept Addl Load After 1.8 Mwe.Caused by Broken Lever Arm.Lever Arms Replaced

ML20085B416
Person / Time
Site:	Palisades
Issue date:	03/10/1972
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085B417	List: ML20085B416
References
NUDOCS 8307080129
Download: ML20085B416 (2)

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3 ,[ D / '7d ,yyh i D. U General Offices: 212 West Mechegan Avenue, Jackson, Mechegan 49201. Area Code S17 788 0550 March 10, 1972 Dr. Peter A. Morris, Director Re: DocketNog0-255 Division of Reactor Licensing License No DPR-20 United States Atomic Energy Commission Washington, DC 20545

Dear Dr. Morris:

This is written to apprise you of a problem experienced with the 1-2 emergency diesel at the Palisades Plant on February 29, 1972.

Plant Condition at the Time of the Incident At the time the incident occurred, the reactor was in a hot shutdown condition while work was being completed on the main trans-fomer bank (bushing replacement).

Description of Incident The 1-2 emergency diesel was placed into operation at 0837 on February 29, 1972 to perform the monthly surveillance test. The governor control operated satisfactorily up to a load of 1.8 MWe (2 5 MWe is nominal full load), at which point the unit would not accept additional load.

The diesel was removed from service at 0943 to make necessary repairs to the unit At this time, a cooldown of the primary system to a point less than 325h was initiated to comply with Technical Specifica-b '

tion requirements.

X Investigation of the emergency diesel governor disclosed a broken yI i lever arm (pawl). This was replaced with a new part and the unit returned f to service at 1307 for continuation of the tests.

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,- The effect of the broken lever arm (pawl) was to restrict load 3 (j- to a evhm of 1.8 MWe due to mechanical blockage of the fuel injection gg

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control mechanism.

Subsequent testing disclosed an erratic main governor. Investi-gation tied this problem to dirty contacts on the droop relay. The relay was replaced and the unit returned to full operability at 1800 on March 3, 1972. -

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e Dr. Pet 2r A. Morris O 2 Docket No 20-255 March 10, 1972 Corrective Action The problem with the emergency governor was corrected with re-placement of the defective lever am with a modified part approximately two times as thick in the area which had broken.

Two additional lever arms are presently on order and the second diesel will be modified as soon as the material is received.

The droop relays were replaced on both units with a closed con-tact type which will not be affected by dust.

Conclusion The diesel was capable of performing its safety function in spite of the droop relay failure as this is not in the circuit during an actual loss of off-site power situation.

The replacement of the lever arms on the emergency governor with one of heavier construction should avoid a reoccurrence of this incident.

Yours very truly, Ralph B. Sewell (Signed)

RBS/ map Ralph B. Sewell Nuclear Licensing Administrator CC: Boyce H. Grier, USAEC L l