ML11214A109

Potential Defect in Qualtech Np Safety Related Motor Control Center Buckets

ML11214A109
Person / Time
Site:	Watts Bar
Issue date:	07/15/2011
From:	Mitchell K Qualtech NP
To:	Office of Nuclear Reactor Regulation, NRC/RGN-III
References
47063
Download: ML11214A109 (2)

Text

0711512011 U.S. Nuclear Regulatory Commission Operations Center Event Report Pague I Part 21 (PAR) Event# 47063 Rep Org: QUALTECH NP Notification Date / Time: 07/15/2011 20:43 (EDT)

Supplier: QUALTECH NP Event Date I Time: 07/15/2011 (EDT)

Last Modification: 07/15/2011 Region: 3 Docket #:

City: CINCINNATI Agreement State: Yes County: License #:

State: OH NRC Notified by: KURT MITCHELL Notifications: TAMARA BLOOMER R3DO HQ Ops Officer: DONALD NORWOOD SCOTT FREEMAN R2DO Emergency Class: NON EMERGENCY PART 21 GRP by EMAIL 10 CFR Section:

21.21 UNSPECIFIED PARAGRAPH POTENTIAL DEFECT IN QUALTECH NP SAFETY RELATED MOTOR CONTROL CENTER BUCKETS The following information was received via facsimile from QualTech NP:

"This letter is issued to provide initial notification of a potential defect in QualTech NP safety related MCC buckets, which were commercial grade dedicated at our Cincinnati facility. On June 9, 2011, TVA Watts Bar Unit 2 notified QualTech NP of a failure on a transformer module associated with an indicator light on the MCC bucket. Based on our investigations, QualTech NP has identified quality and performance issued relating to the 480 VAC input (primary side) portion of the subject indicating light. The light in question has shown the potential to flash/arc internally on the primary winding side of the built in transformer and create a substantial fault current. This fault current not only disables the light but can be large enough to trip the upstream circuit breaker, thus disabling all associated safety related circuitry.

"The issues appear to revolve around inconsistent and poor quality fabrication methods employed during manufacturing, primarily with how the wires were wrapped in critical areas of the primary and how they were routed and attached to the termination points.

"The recommended corrective action for existing safety related MCC buckets is to replace the indicator light and transformer module with a newly qualified acceptable substitute. The new indicator light and transformer module will go through a series of dedication inspections and tests to ensure that a similar failure does not occur.

"Based on review of our records, Tennessee Valley Authority is the only customer to have these defective modules."

07/15/2011 FRI 15:31 FAX 5135283845 2001/001 QualTech NP 4600 East Tech Dr. (Cincinnati, Oil 45245 Phonc: 513.528.7900 *-1x: 513.528.9292 www.qualled'hnp.cw[ .corn CURTISS

_*'A fURIHT, oFlow ControlCompany QualTech NP July 15, 2011 To whom it may concern:

This letter is issued to provide initial notification of a potential defect in QualTech NP safety related MCC buckets, which were commercial grade dedicated at our Cincinnati facility. On June 9, 2011 TVA Watts Bar Unit 2 notified QualTech NP of a failure on a transformer module associated with an indicator light on the MCC bucket. Based on our investigations, QualTech NP has identified quality and performance issues relating to the 480 VAC input (primary side) portion of the subject indicating light. The light in question has shown the potential to flash/arc internally on the primary winding side of the built in transformer and create a substantial fault current. This fault current not only disables the light but can be large enough to trip the upstream circuit breaker, thus disabling all associated safety related circuitry.

The issues appears to revolve around inconsistent and poor quality fabrication methods employed during manufacturing, primarily with how the wires were wrapped in critical areas of the primary and how they were routed and attached to the termination points.

The recommended corrective action for existing safety related MCC buckets is to replace the indicator light and transformer module with a newly qualified acceptable substitute. The new indicator light and transformer module will go through a series of dedication inspections and tests to ensure that a similar failure does not occur.

Based on review of our records, Tennessee Valley Authority is the only customer to have these defective modules.

Additional details will be provided in the formal written report. Please contact Tim Franchuk at 513-528-7900 ext. 176 (office), 803-422-2927 (cell) or via email tfranclhukcurtisswright.com for any additional information.

S incerely,~

Kurtt itchell General Manager QualTech NP, a business unit of Curtiss-Wright Flow Control Company Office 301.854.3432 http://qualteclinp.cwfc.com kmitchell@curtisswright.com