ENS Event | |
|---|---|
05:00 Oct 17, 2017 | |
| Title | Part 21 - Failure of Under-Voltage Release Mechanism |
| Event Description | The following is a synopsis of information received via E-mail:
On October 17, 2017, Palisades alerted Curtiss-Wright of the failure of the under-voltage dropout mechanism in a molded case circuit breaker to trip the breaker in an under-voltage condition. The specific component was a Westinghouse / Eaton Cutler Hammer P/N KD2200U18, containing CAT# UVH3LB08, Style 1492D79G24 under-voltage release mechanism (manufactured prior to 1999). Six of these components were supplied to Palisades in 1992. Findings indicated that the under-voltage release mechanism's failure was a result of a misalignment of the solenoid due to excessive play in the design/manufacturing process which allowed the plunger to miss the target that would cause the breaker to trip in an under-voltage condition. Palisades identified this failure and mentioned two previous failures, one in 1996, and one in 2009. The under-voltage trip mechanism was redesigned in the 1997-1998 time frame. The new design has not exhibited any reported failures. The observed failure on a 1992 breaker having failed in the installed condition took 50 trials to repeat the failure. Given that the excessive play could be a result of combined tolerances, worn tooling, as well as the design itself, and since the OEM has redesigned this mechanism almost 20 years ago, Curtiss-Wright would recommend end users to conduct their own evaluation to determine if a defect, which could create a substantial safety hazard, exists. |
| Where | |
|---|---|
| Curtiss Wright Nuclear Division Cincinnati, Ohio (NRC Region 3) | |
| Organization: | Curtiss Wright Nuclear Division |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+2025.47 h84.395 days <br />12.056 weeks <br />2.774 months <br />) | |
| Opened: | Timothy Franchuk 15:28 Jan 9, 2018 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jan 9, 2018 |
| 53158 - NRC Website | |
Curtiss Wright Nuclear Division with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 531582017-10-17T05:00:00017 October 2017 05:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Failure of Under-Voltage Release Mechanism ENS 516742016-01-21T06:00:00021 January 2016 06:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Notification - Potential Defect in Okonite Tape Splices 2017-10-17T05:00:00 | |