ML20083L809

Forwards Response to IE Bulletin 83-08, Electrical Circuit Breakers W/Undervoltage Trip Feature in Use in Safety- Related Applications Other than Reactor Trip Sys. Breaker Design Info Will Be Forwarded 90 Days from Ltr Date

ML20083L809
Person / Time
Site:	Hatch
Issue date:	04/02/1984
From:	Beckham J GEORGIA POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-83-08, IEB-83-8, NED-84-157, NUDOCS 8404170369
Download: ML20083L809 (5)

Text

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-*3 Georgm Power Company 333 Piedmont Avenue Atlanta,Georga 30308 Tetephone 404 526 7020 Matting Address.

Post Offce Box 4545 Atlanta. Georg:a 30302 g pg 'l] Georgia Power the SOUf50 electnc system J. T. Beckham, J,. -

vee pres, dent and Generat Manager NED-84-157 Nuclear Generation April 2, 1984 U. S. Nuclear Regulatory Cmsnission

REFERENCE:

Office of Inspection and Enforcenent RII: JPO Region II - Suite 2900 50-321/50-366 101 Marietta Street, NW I&E Bulletin Atlanta, Georgia 30303 83-08 ATID?rION: Mr. Janes P. O'Reilly GENTLEMEN:

Georgia Power Cmpany subnits the attached report in response to I&E Bulletin 83-08, "Electriml Circuit Breakers with an Undervoltage Trip Feature in Use in Safety-Related Applications Other than the Reactor Trip Systen." Section 2.a of the bulletin reguests information related to breaker design which is available only fra the manufacturer. The required information has been rejuested frm the appropriate vendors, but a response was not received in time to include in this response. Within 90 days frm the date of this letter, we will forward the requested information or provide an explanation for why it was not made available to us.

J. T. Beckham, Jr. states that he is Vice President of Georgia Power Cmpany and is authorized to execute this oath on behalf of Georgia Power Capany, and that to the best of his knowledge and belief the facts set forth in this lettet are true.

GEORGIA POWER CCMPANY eyGJLES g J. T. Beckhan, Jr.

Sworn to and subscribed before me this 2nd day of April,1984. -

YLNoterf.E & '

/Puoue, Georsta. State at LargeNotary Public PLSjinMY Commamon Ensres Aug.26,1986 Enclosure xc H. C. Nix, Jr.

Senior Resident Inspector J. P. O'Reilly, (NRC-Region II) 8404170369 840402 PDR AF)DCK 05000321 G _ ,

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Georgia Power Canpany Plant'Edwin I. Hatch Units 1 & 2 Response to IE Bulletin 83-08:

Electrical Circuit Breakers with an Undervoltage Trip Feature in Use in Safety Related Applications Other than the Reactor Trip Systen April 2, 1984 a

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d INTRODUCTION In response to I&E Bulletin 83-08, Georgia Power Cmpany provides this report on a review of the application of circuit breakers with undervoltage trip attachnents (UVTAs) in Plant Hatch safety systens.

%e review was conducted in accordance with reccmnendations given in the bulletin: (1) identify the safety related applications of the circuit breakers with UVIAs ard the systems in which they are used; (2) review the adquacy of the design, testing, and maintenance of the breakers in light of their operational experience and information conveyed in the bulletin; and (3) evaluate the need to take corrective measures to ensure proper operation of the breakers. A critical review of project drawings, docments, vendor infcriaation, maintenance procedures and records was done, using criteria established in the Bulletin.

%is report is a partial response to IEB 83-08 due to lack of manufacturers' information. %e final report will be subnitted after our receipt of satisfactory design and maintenance information frm the circuit breaker manufacturers.

RESPONSE

0: 1. Identify applications of W type DB, W type DS, or GE type AK-2 circuit breakers with W trip feature as discussed in IEB 83-01 or 83-04 in safety-related applications at your facility (ies), other than as RIBS. CP holders and licensees should also identify similar applications of other types of breakers by other manufacturers that use a W trip feature. If such circuit breakers are used or planned for use, identify the systen(s) involved.

A: Hatch Nuclear Plant does not use W trip devices on Westinghouse types DB and DS and General Electric type AK-2 circuit breakers.

Other types of breakers with an W trip feature used in safety-related applications at Plant Hatch were identified as follows:

%e Westinghouse Air Circuit Breakers are used in 4160 V BUS 1F (2F on Unit 2) power supply circuits for the following:

Plant Service Water Pmp 1D (2D) - P41-C001D (2P41-C00lD)

Plant Service Water Pmp 1C (2C) - P41-C001C (2P41-C001C)

RHR Service Water Pump 1C (2C) - E11-C001C (2 Ell-C001C)

RHR Pump 1D (2D) - Ell-C002D (2E11-C002D)

CRD Pump 1B (2B) - C11-C001B (2C11-C001B)

RHR Pmp (2C) - Ell-C002C (2E11-C002C) 1 04/02/84 ,

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J UVIAs on Westinghouse Circuit Breakers are used to provide a back-up to the trip function provided by an undervoltage relay which actuates the shunt trip device. @is guarantees that load shedding will occur on BUS 1F (2F) during a loss of off-site power even if battery voltage fails and the shunt trip devices could not operate.

'Ihe General Electric Molded Case Circuit Breakers are used in the power supply circuits fra the Reactor Protection Syst e Motor Generator (MG) Power Sources to Reactor Protection Systen Power i Distribution panels C71-P001 (Unit 1) and 2C71-P001 (Unit 2) .

UVTAs cn GE Circuit . Breakers are used in conjunction with undervoltage, overvoltage and underfrequency monitors to de-energize the.RPS Power Distribution Panel when MG Set output is outside the limits of the RPS quipnent.

l i 0: 2a. For each circuit breaker type identified in Iten - 1, do the i following:

j Review the design of the UVTA and the connecting -linkage. Using i input fra the breaker manufacturer, determine the design margin i available to open the breaker. Evaluate whether or not this design i margin is . adequate in view of safety applications, considering possible problens of aligment, lubrication, adjustment of spring tension, etc., discussed in the " Description of Circunstances."

A: Required design input has been requested fran the manufacturers

. (Westinghouse & _ General Electric) but not received._'We are actively pursuing this information but have no indication of when it will be received. We will provide the re;uested information in a supplanental response' within 90 days or will provide an explanation for why the information is not.available. .;

0: 2b. Describe the current . breaker surveillance program,- including details of test frequency, methodology, and response time i measurement of UVTA device.

f A: Westinghouse Air Circuit Breakers Type 50DHP250 l .

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Circuit breakers . have DC control power undervoltage trip release ~ '

. mechanians. %e UVrA. provides . a back-up -to the' DC- powered trip

l. device. Plant ' Hatch does not have a- specific Circuit Breaker .

. Surveillance Progran for UVms. Circuit breakers are ' checked once -

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every 5_ years (20% each year) as a part . of ~ the - Plant Breaker Preventive Maintenance Progran. UVrAs are not addressed _by ' that-progran.

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General Electric F225 Line Molded Case Circuit Breakers

%e UVIA is tested every 16 months during the RPS MG Set overvoltage, underfrequency, and undervoltage trip functional test or every operating cycle during calibration of RPS MG Set Protection Relays. During the test, the UVTA trips the circuit breaker when its coil becmes de-energized through the action of the voltage and frquency monitors. %e test procedure does not include any response time measursents.

Molded case circuit breakers are factory sealed and, according to available information, preventive maintenance is not rquired by the manufacturer. We are requesting that GE provide their latest position on this matter in light of this Bulletin.

0: 2c. Review operating experience with the circuit breakers in your plant (s) identified in Its 1. Provide a list of all malfunctions (both failure to trip and failure to close on deand) associated with the UVTA, including the connecting linkages and latching mechanisms. The list should include the date of each malfunction, and the operating time prior to failure or date of installation, and the date(s) of major maintenance. In general, when the circuit breaker UVTA is actuated on undervoltage and the breaker contacts do not open within the design time response value, the NRC considers the breaker to have failed.

A: %e investigation of the maintenance history file revealed that no malfunctions have occurred as a result of UVTA failures.

0: 2d. Describe any preventive or corrective measures you have taken, or intend to take, based on the results of Items 2a, 2b, and 2c.

Include any - revisions to the surveillance test progra and methodology. Specifically, address the inherent reliability of the UVTA trip feature in view of its apparent heavy dependence on intensive maintenance and surveillance and whether a basic design change is warranted to correct the proble, e.g., using a voltage sensitive relay to sense loss of voltage and energize the shunt trip coil fra an independent de power source.

A: Westinghouse breakers described in this report utilize the UVTA as a back-up to the primary means for tripping the breaker. We do not believe that a basic design change is needed for either the Westinghouse or GE breakers described in this report. Based on favorable operating experience with both Westinghouse Type 50DHP250 and G.E. F225 breakers,' no preventive or corrective measures have been taken as a result of I.E.Bulletin 83-08. We shall evaluate the need for action after receiving the manufacturers' information for the UvrAs.

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