ML20083R774

Responds to Items 1,2a,2b,2c & 2d of IE Bulletin 83-08, Electrical Circuit Breakers W/Undervoltage Trip Feature in Use in Safety-Related Applications Other than Reactor Trip Sys. Only Ite Type K-600 Breakers Utilized

ML20083R774
Person / Time
Site:	Limerick
Issue date:	04/06/1984
From:	Kemper T PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-83-08, IEB-83-8, NUDOCS 8404240309
Download: ML20083R774 (4)

Text

1 2840605220 PHILADELPHIA ELECTRIC COMPANY 23O1 MARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 JOHN S. KEMPER (2:53 e4i.45o2 APR 6 1984 V IC E-PR ESI D EN T ENG0 NEE M9MG AND RESE ARCse Mr. Thomas E. Murley, Director United States Nuclear Regulatory Commission Office of Inspection and Enforcement, Region I 631 Park Avenue King of Prussia, PA 19406

SUBJECT:

NRC IE Bulletin No. 83-08, Dated 12/28/83 Electric Circuit Breakers with an Undervoltage Trip Feature in use in Safety-Related Applications Other than the Reactor Trip System Limerick Generating Station-Units 1 and 2 FILE: GOVT. 1-1 (IE Bulletin)

Dear Mr. Murley:

Philadelphia Electric Company has reviewed IE Bulletin No. 83-08, as received on January 5, 1984, for Limerick Generating Station. The following is our reply to items 1, 2a, 2b, 2c and 2d:

1. At Limerick, the use of the circuit breaker undervoltage trip attachments (UVTA) in safety related applications will be limited to ITE (now Brown Boveri Electric) type K-600 circuit breakers in eight circuits from the 480 volt safeguard system.

Four of these breakers are used in Unit one and four are planned for Unit two. For each Unit, two of the four breakers supply non-safeguard motor control centers and the remaining two breakers supply 200 horse power reactor building recircul-ation fans. The use of this undervoltage trip feature in the 480 volt feed to the fans is intended to protect the motors from excessive starting inrush current that can oc~ur with low voltages. The use of this feature on the feed to the two non-Class IE motor control centers is to provide automatic isolation from the Class IE load center bus.

2.a The ITE undervoltage trip device does not have a latching mechanism and therefore is not similiar to the General Electric and Westinghouse designs. The ITE device has approximate dimensions of 3"x4"x2". It consists of a clapper type armature that is picked up by current in a coil. With 8404240309 840406 p == ==opg \

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Mr. Thomas E. Murley, Dirsctor 2840605220 voltages above the drop out set point, the armature is in the closed position. The drop out point can be adjusted between 30% and 60% of nominal voltage. At this set point, the low voltage operation is activated and the armature is opened by stored spring energy. This action completes a trip circuit and opens the breaker. The armature will reclose when 80% or more of the nominal voltage is reestablished. Other factors involved with the ITE design are (1) Vibration does not effect its adjustment.

(2) No lubrication is required.

(3) Dust does not accumulate between the magnet and the armature due to the orientation of the magnet and the lack of lubrication.

(4) The manufacturer considers it to be a maintenance free device.

(5) There has been no reported history of problems.

Due to its design simplicity, the ITE device is con-sidered highly reliable. Nevertheless, the failure of these devices to operate will not have any adverse effect on the safe operation of Limerick. Failure to isolate the non-Class IE motor control centers will not overload the diesel generator or Clasa IE power system. Suf-ficient capacity exists to allow continuous operation of these motor control centers under all accident condi-tions. Failure of the UVTA's on the fan breakers will have no adverse consequences as our voltage regulation study has verified that adequate starting voltages will be available to these motors under all scenarios. We are currently considering removing the fan UVTA's because they are not needed.

b. Presently, we plan to test and calibrate Class TE 480 volt load center breakers every 60 months. No special testing of the UVTA's is planned or warranted based on the information supplied above.

c. During preoperational testing for Unit 1, there has been no malfunction attributed to the four ITE undervoltage trip devices on the 480 volt breakers.

d. The design simplicity and operating history of the ITE undervoltage trip device used at Limerick gives confidence that no extraordinary maintenance and surveillance is required.

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Mr. Thomas E. Murity, Dir*.ctor 2840605220 Based on the above reply, we plan no further action on this item.

Sincerely,

^ $- 5 Copy to: Director of Inspection and Enforcentent United States Nuclear Regulatory Conunission Washington, DC 20555 S. K. Chaudhary, Resident NRC Inspector (Limerick)

J. Wiggins, Resident NRC Inspector (Limerick)

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2840605220 COMMONWEALTil 0F PENNSYLVANIA :

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COUNTY OF PilILADELPillA  :

JollN S. KEMPER, being first duly sworn, deposes and says:

That he is Vice President of Philadelphia Electric Company, the holder of Construction Permits CPPR-106 and CPPR-107 f or Limerick Generating Station Ur.its 1 and 2; that he has read the foregoing Response to IE Bulletin 83-08 for Docket No. 50-352 and 50-353 and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.

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Subscribed and sworn to before me this day of /9[M M Notary Public PATmCIA D. *211011 Ne'ary Pubt e, PMavrMs. PMaalvhia ca.

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