ML20003H874

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Provides Addl Responses to NRC Re Adequacy of Station Electric Distribution Voltages.Second Level of Undervoltage Protection Provided to Preclude Fuse & Starter Overheating
ML20003H874
Person / Time
Site: Big Rock Point File:Consumers Energy icon.png
Issue date: 05/04/1981
From: Withrow G
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To: Crutchfield D
Office of Nuclear Reactor Regulation
References
NUDOCS 8105080121
Download: ML20003H874 (2)


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General Offices: 212 West Michleen Avenue, Jackson, MI 49201 * (517) 788 4550 May h, 1981 h

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Director, Nuclear Reector Regulatien 7

Att Mr Dennis M Crutchfield, Chief W4Y0 7 bO h *9 Operating Reactors Branch No 5 u,,, Do,

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DOCKET 50-155 - LICENSE DPR BIG ROCK g

N POINT PLANT - GENERIC ISSUE - ADEQUACY OF STATION ELECTRIC DISTRIBUTION VOLTAGES Censumers Power Company letter dated March 23, 1981 provided responses to the questions of NRC letter dated January 2T, 1981. Staff review of our responses resulted in two additional questions which were answered in a telephone discus-sien.

The following provides a su= mary of those questions and our responses:

Question 1 (Ref Ite= 5 of CPCo letter dated March 23, 1931):

Will the fuses that protect the MCC contactors and starters overheat due to abnormal voltage conditions?

Response

The second level of undervoltage protection has been provided to preclude this Specific details of the undervoltage protection may be found in occurrence.

our June 14, 1978 submittal (Besponse ic(3)).

g.estien 2 (Ref Item 6 of CPCo letter dated March 23, 1981):

Will the electric fire pu=p stall when the condensate pumps are started?

Response

The Item 6 response shows the voltage on Ioad Center (LC) #2 drops to.8028 Pu during condensate pu=p starting. This appears to be a lov value which could result in fire pu=p stalls. It should be noted that the.8028 Pu value is on a

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a Mr Dennis M Crutchfield, Chief Big Rock Point Plant May k, 1981 2

k80 V base and that the fire pump motor is kk0 V rated. Therefore, on a kk0 V base, the LC #2 voltage would be.8757 Pu.

The fire pump motor terminal voitage would be a few percent less due to losses in the cable, but the motor would not stall when the condensate pumps are started.

Gregory C Withrow (Signed)

Gregory C Withrow Senior Licensing Engineer CC JGKeppler, USNRC NRC Resident Inspector-Big Rock Point Plant i

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