ML083150521

Part 21 Report Defect Found in Bussman Fuses

ML083150521
Person / Time
Site:	Cooper
Issue date:	11/06/2008
From:	Madsen D Nebraska Public Power District (NPPD)
To:	Abramovitz M Office of Nuclear Reactor Regulation
References
44634
Download: ML083150521 (2)

Text

11/06/2008 U.S. NuclearRegulatory Commission OperationsCenter Event Report ea-e I Power Reactor Event# 44634 Site: COOPER Notification Date / Time: 11/06/2008 16:27 (EST)..

Unit: 1 Region: 4 State: NE Event Date I Time: 11/06/2008 08:56 (CST)

Reactor Type: [1] GE-4 Last Modification: 11/06/2008 Containment Type: MARK I NRC Notified by: DAVID NELSON MADSEN Notifications: VIVIAN CAMPBELL R4 HQ Ops Officer: MARK ABRAMOVITZ VERN HODGE (E-MAIL) NRR Emergency Class: NON EMERGENCY JOHN THORP (E-MAIL) NRR 10CFR Section:

21.21 UNSPECIFIED PARAGRAPH Unit Scram Code RX Crit Init Power Initial RX Mode Curr Power Current RX Mode 1 N Yes 100 Power Operation 100 Power Operation DEFECT FOUND IN BUSSMAN FUSES "On November 6, 2008, Nebraska Public Power District (NPPD) completed a reportability determination which concluded that a batch of Bussmann fuses with a date code of J47 contained an underlying fabrication vulnerability that could result in a premature failure of the fuse. NPPD has concluded this condition is reportable per 10 CFR Part 21, since the underlying vulnerability could create a substantial safety hazard. The fuses are Commercial Grade items dedicated by NPPD for use at the Cooper Nuclear Station (CNS). The fuses are shipped directly from an authorized Bussmann facility to CNS. The fuse purchasing description is as follows: FUSE; 10 AMP ; 250VAC; ONE-TIME; 50KA I.R. ; GENERAL PUPOSE ; Manufacturer Part Number NON-10. These fuses, with batch code, off J47, have been determined by independent analysis to contain a poor solder joint internal to the fuse.

"These fuses are authorized by NPPD for use in both safety related and non safety related applications. The applicable dedication package identifies one of the safety functions as 'Fuses are required to conduct the design, basis load current without interruption.' If the fuses were installed without the condition being detected and failed upon valid demand of associated circuit, the mission of the associated safety related equipment may not have been accomplished. However, since the fuses were found, the safety function of the installed fuses is maintained and the associated equipment remains operable based on specific instructions for maintaining the fuses in place until replacement. Therefore, this condition is NOT reportable under 10 CFR 50.72 or 50.73. However, installation could have occurred and remained undetected, thus introducing a common mode failure in certain applications, thus fulfillingthe definition of a Substantial Safety Hazard as defined by 10 CFR Part 21. Based on independent <

analysis of fuse mode of failure, the defect may not be necessarily detected upon installation. Since the fuses were stocked in unrestricted spares for essential applications, 10 CFR Part 21 applies, and the condition is reportable under 10 CFR 21.21. The Responsible Corporate Officer has been notified of this condition per 10 CFR 21.21 (d)(3)(i) on November 6, 2008 at 08:56 AM, CST. Pursuant to 10 CFR 21.21 (d)(3)(ii) written notification is due to the NRC within 30 days of this notification."

11/06/2008 U.S. Nuclear Regulatory Commission OperationsCenter Event Report Page2 Power Reactor Event# 44634 Forty fuses were in the defective lot of which 15 are still installed in plant systems: Circ Water, RCIC, Emergency Diesel Generator 2, air removal and 4160 VAC diesel start breaker circuitry.

The licensee notified the NRC Resident Inspector.

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