ML20101L966

Part 21 Rept Re Discovery of Klockner-Moeller 480-volt Breaker in Tripped Condition Due to Fracture of Plastic Arm within Breaker.Two of Three Failed Breakers Sent to Mfg for Analysis.Results Expected by End of Jul 1992

ML20101L966
Person / Time
Site:	North Anna
Issue date:	07/01/1992
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-92 92-441, NUDOCS 9207080003
Download: ML20101L966 (3)

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. h1ROIN1f. ELECTRIC AND POWElt COMI'ANY RICIIMOND,VIHUINIA 202 61 l'

B July _1, 1992 Ll.

' Document Control Desk Serial No.92-441

' U.S. Nuclear Regulatory Commission NAPS /RMNR4 L

Washington, D.C. 20555 Docket Nos. 50-338 J

50-339 L

License Nos. NPF-4 NPF-7 Gentlemen:

VIRGINIA ELECTRIC AND -POWER COMPANY l

NORTH ANNA POWER STATION IJNIIS,1&L2 REPORT OF DEFECT IN ACCORDANCE WITH 10 CFR 21

_On Ju'nc 16,1992, we discovered a 480 volt breaker in a tripped condition. We L

subsequently determined that the failure mode was the same as two previous i

failures that occurred on the same model breaker. Based on our evaluation, we concluded that the condition identified met-ths requirements for reporting according to 10 CFR 21.

in accordance with 10 CFR 21, the following information is provided:

j

- 1. Name and address of the individualinforming the Commission:

Mr. W. L. Stewart Senior-Vice Prasident - Nuclear

. Virginia Electric and Power Company 5000 Dominion Boulevard.

. Glen Allen,' Virginia 23260.

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2. Identification of the facility or component that contains the defect-

-1 North Anna Power Station Units 1 and 2 Klockner-Moeller model NZM6-63 480 voit breakers

3. Identification of the firm supplying iho component which contains the

. defect:

L Klockner-Moeller 25 Forge Parkway Franklin, Massachusetts 02038 Point of contact: Mr. Thomas Erskin (508) 520-7080 OdOjCd l

9207080000 9207o1 i

PDR ADOCK 050oo338

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4. Nature of the defect and the safety hazard which is created or could be created by the defect:

Three Klockner-Moeller model NZM6-63 480 volt breakers have failed open due to fracture of a plastic arm within the breaker. All three have failed in the same manner, with the same point of breakage. One aoditional breaker, which was not in service, has cracks !n the plastic arm, although it did not fail. Failure of these breakers would make the associated equipment inoperable. The three failures were associated with Unit 2 motor operated valves in the charging and safety injection systems.

5. The date on which information on this defect was obtained:

The Vice President - Nuclear Operations obtained the results of the evaluation on June 30, 1992, in accordance with our administrative procedures for addressing potential 10 CFR 21 reportable items.

6. The number and location of all such components in use at the facility:

There are approximately 439 NZM6-63 breakers installed at North Anna. The three failed breakers were in the Unit 2 Cable Vault and Tunnel Area and were part of the charging or safety injection systems.

7. The corrective actiors which has been, is being, or will be taken; the name of the individua! or organization responsible for the action; and the length of time that has been or will taken to complete the action:

Two of the failed brsaers have been sent to Klockner-Moeller for analysis. One failed breaker and tile breaker with the cracked plastic arm that had not yet failed are being analyzed by Virginia Power. Results are expected by the end of July 1992. A list of installed breakers has been prepared and prioritized by application and function.

This prioritization will be used to schedule breaker inspections or replacements. We have also implemented increased surveillance of safety-r61ated breaker position in the control room.

8. Any advice related to the defect that has been or will be given tc purchasers or licensees:

Virginia Power has conducted a scarch using NPRDS, the Nuclear Network and NOMIS and has not found any other nuclear utility using Klockner-Moeller model NZM6-63 480 volt breakers, including our Surry Power Station.

c-Should-you have any questions or require additional information, please contact us.

Very truly yours,

[

i 1A W. L. Stewa.1 Senior Vice President - Nuclear cc:

Regional Administrator U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.

Suite 2900 Atlanta, GA 30323 Mr. M. S. Lesser -

NRC Senior Residerit inspector North Anna Power Station Mr. Thomas Erskin Klockner-Moeller 25 Forge Parkway Franklin, Massachusetts 02038 9

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