ENS 57827
ENS Event | |
|---|---|
04:00 May 21, 2025 | |
| Title | Part 21 Interim Report of Deviation |
| Event Description | The following is a synopsis of information provided by Curtiss-Wright (CW) via email:
On 5/21/2025, Xcel Energy notified Curtiss-Wright about the failure of two NAMCO limit switches provided under CW project CJ21087 (tag number CJ2108701, serial numbers 01 and 04). The limit switches were dedicated by CW and shipped on 2/28/2025 to Xcel Energy. The switches failed a bench test performed by Xcel Energy, which aimed to verify that the contacts properly revert to their original state during spring return. Xcel Energy found that the contacts reverted to their original state prior to the audible click/snap, which is supposed to indicate contact changeover. The two units were returned to Curtiss-Wright on 5/29/2025. The test result was fully duplicated on one of the switches. For the other switch (serial number 04), the switch contacts intermittently failed to return to the original state at all, requiring manual assistance to do so. On 6/26/2025, CW sent the parts to NAMCO for repair. CW retested the parts after the repair. Part 04 still had the same issue with failing to reset as noted earlier. That limit switch was returned to NAMCO for a full evaluation. CW anticipates an update to this notification with final results on 9/23/2025. Potentially affected U.S. nuclear power plants: unknown at the time of the notification. Contact Information: Mark Papke Quality Assurance Manager Curtiss-Wright 4600 East Tech Drive Cincinnati, OH 45245 mpapke@curtisswright.com
The following information was provided by Curtiss-Wright (CW) via email: On 6/26/2025 CW sent the relays to NAMCO for repair and the parts were returned to CW on June 26. CW retested the limit switches and one failed for the same issue as noted earlier, the failed limit switch was returned to NAMCO for a full evaluation. The failure is still under investigation and CW has been in communication with NAMCO, the manufacturer. Once the evaluation is complete this report will be updated. CW anticipates an update to this notification with final results on 11/24/2025. Notified R3DO (Szwarc) and the Part 21/50.55 Reactors group
The following information was provided by Curtiss-Wright (CW) via email: The NAMCO evaluation/report issued to CW on September 4, 2025, concluded that the failure was caused by improper sizing of the hub on the top of the shuttle/slide assembly. The hub was too small which prevented proper fit with the latch and, therefore, the switch could not open or close as intended. NAMCO confirmed that this failure was only reported on PN: EA700-80926, Date Code: 0425 and also confirmed that the design of PN: EA700-80926 nor supplier of the shuttle/slide assembly has not changed in many years. NAMCO has changed their supplier for the shuttle/slide assembly since the manufacture of PN: EA700-80926, Date Code: 0425. It should also be noted that NAMCO now performs the slow latch test as stated above on all limit switches, not just the E700 series. To address this issue, CW will be revising all affected NAMCO limit switches' dedication plans to incorporate the slow latch test. CW recommends that end users should perform slow latch testing as a part of their bench or field test procedures upon receiving any Namco limit switches. These actions should preclude a possible recurrence of this failure mechanism. Please note that CW has not supplied P/N: EA700-80926 of the impacted date code 0425 to any other end users. Notified R3DO (Orlikowski) and the Part 21/50.55 Reactors group |
| Where | |
|---|---|
| Curtiss Wright Flow Control Co. Cincinnati, Ohio (NRC Region 3) | |
| Organization: | Curtiss Wright Flow Control Co. |
| Reporting | |
| 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
| Time - Person (Reporting Time:+1565.78 h65.241 days <br />9.32 weeks <br />2.145 months <br />) | |
| Opened: | Margie Hover 09:47 Jul 25, 2025 |
| NRC Officer: | Kerby Scales |
| Last Updated: | Nov 20, 2025 |
| 57827 - NRC Website | |
Curtiss Wright Flow Control Co. with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
WEEKMONTHYEARENS 578272025-05-21T04:00:00021 May 2025 04:00:00
[Table view]10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 Interim Report of Deviation ENS 575992025-01-07T04:00:0007 January 2025 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 Interim Report of Deviation ENS 568212023-08-30T07:00:00030 August 2023 07:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 - Inconsistent Potentiometer Resistance Values ENS 566832023-06-22T04:00:00022 June 2023 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 Interim Report - Failure of Curtiss Wright Supplied Safety Related Relay ENS 559602022-04-24T04:00:00024 April 2022 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 Report - Potential Defect in Quick Disconnect Connector Cable Assemblies ENS 509002015-03-17T04:00:00017 March 2015 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Interim Part 21 Report - Potential Test Induced Defect in a 0867F Main Steam Safety Relief Valves ENS 489962013-05-03T04:00:0003 May 2013 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Interim Part 21 Report of Potential Defect in a Relief Valve Bellows 2025-05-21T04:00:00 | |