ML20202D467

Part 21 & Interim Deficiency Rept,Item 226 Re Failure of Brown-Boveri 480-volt Switchgear Breakers.Initially Reported on 860226.Testing Continuing Until Failure Mode Determined. Next Rept Expected by 860616

ML20202D467
Person / Time
Site:	Harris
Issue date:	03/28/1986
From:	Watson R CAROLINA POWER & LIGHT CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
CON-NRC-436, REF-PT21-86, REF-PT21-86-116-000 226, HO-860283-(), HO-860283-(O), PT21-86-116, PT21-86-116-000, NUDOCS 8604110556
Download: ML20202D467 (2)

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lina Power & Light Company g bp.3 oD y

b HARRIS NUCLEAR PROJECT P. O. Box 165 New Hill, North Carolina 27562 MAR 2 81385 l

File Number:

SHF/10-13510E NRC-436 Letter Number:

H0-860283 (0)

Dr. J. Nelson Grace United States Nuclear Regulatory Commission Region II 101 Marietta Street, Northwest (Suite 2900)

Atlanta, Georgia 30323 CAROLINA POWER & LICHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT 1986 - 900,000 KW - UNIT 1 480V SWITCHCEAR BREAKERS, ITEM 226

Dear Dr. Grace:

On February 26, 1986, CP&L (Mr. N. J. Chiangi) notified the NRC (Mr. P. Fredrickson) of a potentially reportable item under the provisions of 10CFR 50.55(e) and 10CFR, Part 21.

This problem was addressed by Site Nonconformance Report 86-0091 on February 12, 1986. As described in the nonconformance report, two breakers failed to trip electrically or manually while connected to loads. The breakers lodged internally and could not be opened.

Since the occurrence of this nonconformance, the vendor (Brown-Boveri) has attempted to simulate this failure by cycling a breaker, open and closed, until a similar failure occurs. As of March 18, 1986, Brown-Boveri has been unable to determine the mode of failure of these breakers. The breakers that failed were being used to support Hot Functional testing and were being cycled frequently to maintain the parameters necessary for Hot Functional testing. In light of the frequent operations experienced in this application, Brown-Boveri feels that this failure can be duplicated by cycling a test breaker at their Columbia, South Carolina, plant. Brown-Boveri has several failure modes postulated for this item; but to date, the specific breaker failure mode has not been determined. The testing will continue until a failure mode is determined.

Once Brown-Boveri completes their analysis of the failure and CP&L reviews the results, a report will be issued to the NRC. It is currently projected that we will require until June 16, 1986 to report on the reportability of this item.

8604110556 860328 PDR ADOCK 05000400 s

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Thank you for your consideration in this matter.

Yours very truly, R. A. Watson Vice President Harris Nuclear Project i

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cc: Messrs. C. Maxwell (NRC-SHNPP)

I J. M. Taylor (NRC)

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