Morning Report for May 17, 2006

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Part 21 2006-0008: Notification Involving Potential Defect in Aerovox Capacitor


Columbus, Ohio

License No:

MR Number: H-2006-0010
Date: 05/04/2006

Source Document: E-MAIL



The NRC was notified of the subject 10 CFR Part 21 report by the vendor, Ametek Solidstate Controls, as documented previously under Event Notification No. 42551. The vendor provided in the notification a "rudimentary" list of the US nuclear plant sites that have these type of capacitors installed in their equipment or in their spare parts inventory.

U.S. plants with capacitors installed in equipment: Oconee, McGuire, Watts Bar, Browns Ferry, South Texas Project, Beaver Valley, San Onofre, Nine Mile Point and Three Mile Island.

U.S. plants with capacitors in spare part inventory: Saint Lucie, Palo Verde, Surry, Turkey Point, Diablo Canyon, Shearon Harris, Crystal River, H.B. Robinson and Comanche Peak.

The NRC has contacted the vendor and they now believe the list of affected U.S. plants is complete; no additional sites are expected to affected. The affected sites were notified of this condition via e-mail by the vendor.

The Event Notification No. 42551 was posted on the NRC website on May 5, 2006 at:

The entire notification is also available in the NRC ADAMS system under Accession Number: ML061300626.

This notification describes the following information regarding the capacitors involved:
Component: 13uF X 1000V AC capacitors, SCI P/N 07-020139-00, Aerovox P/N H94S1013A0BA, manufactured between January 2004 and December 2004.

These capacitors can be either installed in Ametek Solidstate Controls UPS [uninterruptible power supply] equipment or provided as a spare part. The components are schematically identified as C805, C815, or C705.

The capacitor failures due to this defect will occur early in the operating life of the device. There are no warning signs that a failure is imminent, or detection method for predicting an approaching failure.

The vendor investigation has revealed that the capacitor failures (date codes 0408 and 0436) were due to manufacturing defects. A failure analysis by Aerovox revealed that a foil tab connecting the capacitor winding to the internal terminal became pinched between the lid and the can during the seaming operation. Within the first year of operation, the insulation covering the connecting tab was cut through. This resulted in terminal to case short.

The failures described above, could result in loss of output voltage and transfer of the static switch to the bypass source. The resulting failure could result in a potential damage to the load.

The observed failure rate of this component is very low at 0.06% (2 out of 3336 units manufactured between 1/1/04 and 12/31/04). Aerovox has implemented corrective actions to preclude further failures.

Based upon the Aerovox evaluation, Ametek Solidstate Controls believes if a defect was present in a capacitor, the likelihood of a failure should occur early in the operating life. The vendor believes the failure rate has been extremely low and the risk is minimal, however, each operating facility will need to evaluate the potential risk to their operation.

The notification provides a list of affected US stations (discussed earlier), as well as, international stations affected: Korea Hydro, Nuklearna Elec Vrbina, China Nuclear, Laguna Verde and Electrobras.

The vendor states they will work with the affected sites to arrange replacements.

Vendor contact information on this issue was provided as: Mrs. Jean Falor, Ametek Client Services group at 1-800-222-9079 or 1-614-846-7500 ext. 6230, or via email at

Accession Numbers:

Accession No Accession Date
ML061300626 05/04/2006


Name Office Abbrev Phone No E-Mail
TABATABAI, OMID NRR (301) 451-6616
KING, MARK S NRR (301) 415-1150

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