ML20085F478

RO UE-75-2:on 750329,control Rod 30 Failed to Drop Properly During Rod Drop Timing Test.Cause Not Determined.Further Investigation to Be Conducted at Next Cold Shutdown

ML20085F478
Person / Time
Site:	Palisades
Issue date:	04/10/1975
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Office of Nuclear Reactor Regulation
References
RO-UE-75-2, NUDOCS 8308220119
Download: ML20085F478 (2)

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• Area Code 517 788-0550 April 10, 1975

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Division of Reactor Licensing -

Re: Docket 50-255 US Nuclear Regulatory Comission License DPR-20 Washington, DC 20555 Palisades Plant UE-75-2 Gentlemen:

Attached is Unusual Event Report UE-75-2 which covers the

) failure of Control Rod No 30 to drop properly. This failure occurred N._,/

during testing with the plant in hot shutdown and there was no effect on plant operation.

The Palisades Technical Specifications permit plant operation with an inoperable control rod.

Very truly yours, Ralph B. Sewell (Signed)

DAB /ce Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USNRC

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pd 9308220119 750410 4025 PDR ADOCK 05000255 S PDR i

COPY SENT REGION . 2

l 1N i f O UNUSUAL EVENT REPORT l

Palisades Plant

1. Report No: UE-75-2, Docket 50-255 2a. Report Date: April 1, 1975  !

2b. Occurrence Date: March 29, 1975

3. Facility: Palisades Plant, Covert, Michigan J

4. Identification of Occurrence: Control Rod No 30 failed to drop properly during rod drop timing test.

5. Conditions Prior to Occurrence: The reactor was in the hot shutdown condition.

6. Description of Occurrence: On March 29, 1975 CRDM torque and control rod drop testing was being conducted. During the testing, Control Rod No 30 failed

! to drop properly when the clutch switch was opened. Successive testing showed i rou6h operation coupled with slow or incomplete rod drops.

! 7 Apparent Cause of Occurrence: An apparent cause of the event has not been de-termined. Further investigation will be conducted at the next cold shutdown.

O 8. Analysis of Occurrence: PRC review of the incident concluded that plant opera-tion can continue per Technical Specifications Section 3.10.4.b. The control l

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rod is mechanically operable but is classified as " inoperable" because it ca ,- l not be satisfactorily tripped.

l 9. Corrective Action: The following corrective action was taken or will be taken:

a. It was recommended that this control rod not be further exercised or oper-ated unnecessarily and so noted in daily orders in shift supervisor's office.

b. Continue the investigation into the cause of the malfunction. Engineering assistance is to be provided to follow up on the repair of the drive unit.

1 j 10. Failure Data:

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] a. There is no record of any previous malfunctions of this type on any of the CRDMs.

b. Control Rod Drive No 30 manufacturer is Combustion Engineering, Inc and the piece number is J-2966-163-001.

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