ML20023B672

Final Deficiency & Part 21 Repts Re 480-volt Switchgear Design Defect in Secondary Disconnects.Initially Reported on 821102.Brown-Boveri Completed change-out of All Old Style Stationary Secondary Disconnects

ML20023B672
Person / Time
Site:	Harris
Issue date:	04/29/1983
From:	Parsons R CAROLINA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
CON-NRC-66, REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8305050259
Download: ML20023B672 (4)

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%  % : 0, Carolina Power & Light Company '7 - s J 4

P. O. Box 101, New Hill, N. C. 27562 April 29, 1983 hp

• dp Mr. James P. O'Reilly NRC-66 United States Nuclear Regulatory Commission Region II 101 Marietta Street, Northwest (Suite 3100)

Atlanta, Georgia 30303 i

CAROLINA POWER & light COMPANY SHEARON HARRIS NUCLEA7. POWER PLANT 1986 900,000 KW - UNITS 1 & 2 480V SWITCHGEAR DESIGN DEFICIENCY OF THE SECONDARY DISCONNECTS, NY-435171, ITEM 106

Dear Mr. O'Reilly:

Attached is the final report on the subject item which was deemed reportable per the provisions of 10CFR50.55(e) and 10CFR, Part 21, on November 2, 1982.

With this report, Carolina Power and Light Company considers this matter closed.

If you have any questions regarding this matter, please do not hesitate to contact me.

Yours very trtily, 2, Yh. am R. M. Parsons Project General Manager Shearon Harris. Nuclear Power Plant RMP/sh Attachment cc: Mr. G. Maxwell (NRC-SHNPP)

Mr. R. Prevatte (NRC-SHNPP)

Mr. V. Stello (NRC)

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PDR ADOCK 05000400 8

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. Y CAROLINA POWER & LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT UNIT NO. 1 480V SWITCHGEAR DESIGN DEFICIENCY OF THE SECONDARY DIECONNECTS' ITEM 106 FINAL REPORT April 29, 1983 REPORTABLE UNDER 10CFR50.55(e)

AND 10CFR21 l

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SUBJECT:

Shearon Harris Nuclear Power Plant Unit 1 10CFR50.55(c) and 10CFR21 reportable deficiency on the secondary disconnects on the 480V switchgear: . Item 106.

ITEM: Secondary disconnects located on the circuit breaker cradles'on-the 480V switchgear'hich w mate 1with the finger contacts on the circuit breaker.

SUPPLIED BY: Brown-Boveri Company, Chalfont, Pa.

NATURE OF DEFICIENCY: :From April 1982 to November 1982, Brown-Boveri Company shipped Class lE 480V switchgear to the Shearon Harris site under Purchase Order NY-435171. In October 1982, it was discovered that the circuit breaker cradles were assembled using an older design of the secondary disconnects.

(The secondary disconnects are the' points where control -

power is supplied to the circuit breaker.) This older design was manufactured with rectangular tabs, that hold

, contact strips in place, and also a small cut-out in the contact strip located directly behand.the rectangular tab (Part No. 712209-TI).

-Brown-Boveri has advised us that there is a chance that the finger contacts can get caught behind the rectangular tabs in the-contact strip cut-out and can break-off when the circuit breakers are racked out of the cradles.

Therefore, control power to the circuit breakers could be lost.-

DATE PROBLEM REPORIED: November 2,.1982 - CP&L (C. L. McKenzie) notified the NRC

'( C. Hehl) that this item is reportable under 10CFR50.55(e) c and 10CFR21.

SCOPE OF

PROBLEM

The deficiency involves four Unit 1 Class 1E 480V switchgear

-(52 cubicles).

1-SAFETY l IMPLICATIONS: The Class lE 480V switchgear supplies electrical power to nuclear safety-related equipment. Loss of. control power to_certain circuits in the 480V switchgear circuit breaker-l could result in improper functioning of the circuit breaker and thus affect power availability to nuclear safety-related equipment.

CORRECTIVE ACTION

The secondary disconnects presently installed in the i

breaker' cradle will be replaced with a newly designed j secondary disconnect that will not cause the finger i contacts on the circuit breaker to break (Brown-Boveri Part No. 712209-T2).

FINAL REPORT: A Brown-Boveri Service Representative has' completed the change-out of all the old style stationary secondary disconnects (Part No. 712209-TI) to the new style stationary disecanects (Part No. 712207-72).

A site construction inspector observed and checked to ensure that all work was performed in accordance with the BBC supplied change-out procedure. We' now consider all work on this item to be complete.

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