PNO-III-97-031, on 970401,licensee Identified Fractures on Auxiliary Switch Contact Block Mounted on 4 Kv Breaker Prior to Installation in Unit 2 safety-related Bus.Licensee Presently Testing Similar Breakers

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PNO-III-97-031:on 970401,licensee Identified Fractures on Auxiliary Switch Contact Block Mounted on 4 Kv Breaker Prior to Installation in Unit 2 safety-related Bus.Licensee Presently Testing Similar Breakers
ML20137Q575
Person / Time
Site: Quad Cities  Constellation icon.png
Issue date: 04/10/1997
From: Kropp W, Lerch R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-97-031, PNO-III-97-31, NUDOCS 9704110042
Download: ML20137Q575 (2)


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. April 10, 1997 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-97-03 '

i This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by Region III staff (Lisle Illinois) on this date.

Facility Licensee Emergency Classification Commonwealth Edison Co. Notification of Unusual Event Quad Cities 1 2 Alert Cordova. Illinois Site Area Emergency

~ Dockets: 50-254.50-265 General Emergency X Not Applicable

Subject:

OUTAGE DUE TO IN0PEPABLE 4 KV BREAKERS On April 1.1997, the licensee identified fractures on an auxiliary switch contact block mounted on a 4 kV breaker prior to installation in a Unit 2 safety-related bus. The failure resulted in an auxiliary switch contact block physically separating from the support mount. The licensee inspected siniilar spare breakers and ide'itified 12 of 14 breakers with cracked auxiliary switches.

On April 8. 1997. the licensee removed and replaced two residual heat removal service water (RHRSW) pump breakers in Unit 1 due to finding .

cracked switches. On April 9.1997, the licensee declared all similar breakers of Merlin-Gerin origin inoperable. This caused all breakers in 4 kV busses 13. 14. 23. and 24 to be considered ino]erable. That action rendered all RHRSW pumps ar.d feeder breakers to tie 1E busses inoperable (but functional) for both units.

The licensee commenced shutdown of Unit 1 on April 9.1997, as required by Technical Specifications. Unit 2 is currently in a refueling outage. A manual trip of the Unit I reactor was inserted at 00:06 a.m. (CDT) on A)ril 10,1997. As of 10:16 a.m. on April 10. 1997. Unit 1 was in cold s lutdown. -

The Merlin-Gerin breakers (style AMGH-5-350-12) were distributed by Pacific Breakers and had been phased into use on both units in the past three years. The licensee also has used these breakers at the Dresden Nuclear Station, and is also evaluating these breakers. At present, the licensee has identified no significant problems with the breakers at Dresden.

The licensee is aresently testing similar breakers and analyzing material in an offsite la) oratory in an attempt to better understand the cause of the defect.

NRC resident inspectors observed the reactor shutdown activities. An NRC vendor inspection branch visit to the Quad Cities Nuclear Station is scheduled to begin April 14. 1997.

The States of Illinois and Iowa will be notified. The information in this i preliminary notification has been reviewed with licensee management. i 39 l l

9704110042 970410 PDR I&E PNO-III-97-031 PDR Dl

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[ PNO-III-97-031 1 The licensee notified the NRC Ope;'ations Center at 1:37 p.m. (CDT) on i

April 9,1997. This information is current as of 10:30 a.m. (CDT) on April 10, 1997. l

Contact:

WAYNE KROPP ROBERT LERCH (630)829-9633 (630)829-9759 i l

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