ENS 55836
ENS Event | |
|---|---|
04:00 Apr 6, 2022 | |
| Title | Part 21 - Westinghouse Actuator Full Voltage Reversing Contactors Deficency Report |
| Event Description | The following information was provided by the licensee via email:
The following information is provided pursuant to the requirements of 10 CFR Part 21 to report a defect that could lead to a substantial safety hazard. Name and address of the individual informing the Commission: Camille T. Zozula Westinghouse Electric Company 1000 Westinghouse Drive Cranberry Township, Pennsylvania 16066 (412) 374-2577 zozulact@westinghouse.com Commercially dedicated Eaton Freedom Series NEMA Size 1 and 2 full voltage reversing (FVR) contactors with mechanical interlocks that were manufactured between April 2014 until June 2018. The [FVRs] are designed and qualified to open and close on demand. The FVR contactors sporadically failed to electrically close on demand because the mechanical interlock is not returning to the de-energized position. Westinghouse sold LaSalle County Station Units 1 and 2 a quantity of 206 safety related FVR contactors that are potentially affected between 2014 and 2022. Westinghouse developed an alignment tool intended to increase the effectiveness of the installed mechanical interlocks and prevent them from binding. Westinghouse provided the alignment tool and associated procedure to LaSalle on February 17, 2022. Effective March 11, 2022, Westinghouse updated the commercial dedication instruction to include additional critical characteristics of the mechanical interlock assembly based on the results of the causal analysis. It was determined that the pawl contained within the mechanical interlock assembly was the cause of the mechanical binding. Westinghouse purchased the latest revision mechanical interlocks that contain Revision 3 pawls from Eaton. They are being dedicated by Westinghouse and installed by LaSalle Station in conjunction with the alignment tool, as they become available. Westinghouse has been in daily communication with LaSalle Station since January 2022 and provides real-time updates on the Westinghouse testing efforts. Westinghouse provided an on-site expert to LaSalle between February 23-25, 2022. The overall failure rate of the installed components has been low and is related to a tolerance stack-up among the mechanical interlock, mechanical interlock pawl, and the two reversing contactors. Additionally, the failures only occur after some time in service which cannot be correlated to a specific installed time or number of cycles. It is a random event. Westinghouse analyzed, reviewed, and regression tested mechanical interlocks that contain the Revision 3 pawls to confirm they are functional and meet the LaSalle environmental requirements. |
| Where | |
|---|---|
| Westinghouse Electric Company Cranberry Township, Pennsylvania (NRC Region 1) | |
| Organization: | Westinghouse Electric Company |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+137.02 h5.709 days <br />0.816 weeks <br />0.188 months <br />) | |
| Opened: | Camille Zozula 21:01 Apr 11, 2022 |
| NRC Officer: | Mike Stafford |
| Last Updated: | Apr 11, 2022 |
| 55836 - NRC Website | |
Westinghouse Electric Company with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 573042024-09-04T23:09:0004 September 2024 23:09:00
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