ENS 45686
ENS Event | |
|---|---|
05:00 Feb 8, 2010 | |
| Title | Potential Failure of a Breaker Component to Comply with Design Specifications |
| Event Description | The following information was received via facsimile:
A breaker failed during operation at Plant Vogtle during operation. A failure analysis indicated that the resistors on the electronic board fail to an open circuit status. On January 14, 2010, a failure analysis indicated that the resistors fail to a short circuit status prior to failing open. In this failure mode, the internal temperature increases to a point where the plastic core melts and thereby can potentially block the operation of the internal plunger. In such a case, the breaker remains closed, but if the breaker is opened then a new closing command is not possible. ABB is taking, or has taken, the following corrective actions: A. As noted above, the only affected customer with a failed breaker is Southern Company's Nuclear Plant Vogtle, and ABB has discussed this issue with Southern Company. An interim report was issued on 1-18-2010. B. As an interim solution, ABB will provide a standard close coil. This solution will be limited to applications that do not require the low impendence in the close coil for lamp applications. C. An alternate solution is to add 'b' contact (normally closed) in series with the existing close coil. While not having a history of failure, it is noted that similar breakers are used at Plant Hatch. Given the large number of applications for the affected circuit breakers, ABB (Medium Voltage Service) cannot determine if the potential for a substantial safety hazard exists at any licensee's facility if a similar failure of the close coil occurs. As noted above, the failure has been limited to applications that require continuous close coil duty. No failures have been reported or produced in testing in applications with intermittent use of close coil duty. Licensees are requested to evaluate the application of affected breakers to determine priority of close coil replacement.
The identification of the subject component is as follows: ABB PIN ISDA055274Rl Close Coil x Lamp. These close coils are used in Sace EMAX breakers exclusively provided to Southern Nuclear Company plant Vogtle for safety related applications. The close coils are used to release stored energy that in turn closes the breaker. The failure is limited to applications with constant voltage applied to the close coil. Intermittent use of the close coil has not resulted in any failures. ABB Sace EMAX circuit breakers procured from ABB between 2006 to present for Vogtle may have suspect close coils installed where the particular application requires constant control voltage to be applied to the close coil. ABB is taking, or has taken, the following corrective actions: a. As noted above, the only affected customer is Southern Company's Nuclear Plant Vogtle, and ABB has discussed this issue with Southern Company. An initial notification letter was issued on 2-18-2010. b. ABB will provide a standard close coil 1SDA0383013R1. This part number has been updated from the 2-8-2010 notification and is based on ABB Sace input. This solution will be limited to applications that do not require the low impedance in the close coil for lamp applications. |
| Where | |
|---|---|
| Abb Inc. (Medium Voltage Service) Florence, South Carolina (NRC Region 1) | |
| Organization: | Abb Inc. (Medium Voltage Service) |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+11.63 h0.485 days <br />0.0692 weeks <br />0.0159 months <br />) | |
| Opened: | William Conlon 16:38 Feb 8, 2010 |
| NRC Officer: | Vince Klco |
| Last Updated: | Mar 8, 2010 |
| 45686 - NRC Website | |
Abb Inc. (Medium Voltage Service) with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 456862010-02-08T05:00:0008 February 2010 05:00:00
[Table view]10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Potential Failure of a Breaker Component to Comply with Design Specifications 2010-02-08T05:00:00 | |