ENS 55095
ENS Event | |
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05:00 Dec 9, 2020 | |
Title | Part 21 Report - Actuator Failure Due to Loose Cam Pins |
Event Description | The following is a summary of the report provided by the supplier:
Flowserve - Limitorque was informed that during testing of a SMB-0 actuator prior to installation, the actuator failed to return from the manual handwheel mode to motor operation mode. Site personnel removed the electric motor from the actuator and discovered that the worm shaft gear cam pin had become detached from the worm shaft clutch gear. The actuator was one of six identical actuators supplied to Ontario Power Generation by Limitorque in January 2020. Subsequent site inspection of five other actuators received on the order revealed that the cam pins were loose in the worm shaft clutch gear. The issue was discovered prior to placing any of the actuators into service. The defect was the result of improper assembly of the worm shaft clutch gear. The machinist manufacturing the component failed to complete the step require to permanently retain the cam pin in position. Although no other occurrences of this issue have been reported, Flowserve is continuing to evaluate this issue regarding the potential extent of condition. Currently, there are no recommended actions for the nuclear plants concerning this Part 21 notification. The supplier has not identified any affected plants at this time and continue to evaluate the extent of condition. Part number containing the worm shaft clutch gear: 60-420-0130-1 Corrective Actions: The six gears affected were returned to Limitorque for evaluation and replacement. All SMB worm shaft gears of similar design were placed on temporary quality assurance hold for enhanced inspection. No defective parts were found. All worm shaft gears currently being manufactured will have an additional quality control inspection point for proper cam pin installation. Point of contact: Kyle Ramsey, Senior Product Engineer at Flowserve-Limitorque Actuation Systems, 5114 Woodall Road, Lynchburg, VA 24502, Office number: 434-522-4138
Flowserve's investigation has concluded that the assembly error that resulted in the defect being reported was an isolated incident affecting the six parts identified below that were manufactured on a single work order in January 2020. No other gears were manufactured on that work order. Production records indicate that approximately 400 SMB-0 worm shaft clutch gears have been manufactured for nuclear and commercial applications in the past four years. No other instances of loose cam pins have been reported. Notified R1DO (Arner), R2DO (Miller), R3DO (Peterson), R4DO (Azua), and Part 21 Reactors Group (email). |
Where | |
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Flowserve Lynchburg, Virginia (NRC Region 1) | |
Organization: | Flowserve |
Reporting | |
10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
Time - Person (Reporting Time:+1374 h57.25 days <br />8.179 weeks <br />1.882 months <br />) | |
Opened: | Tyler Thompson 11:00 Feb 4, 2021 |
NRC Officer: | Brian Lin |
Last Updated: | Apr 20, 2021 |
55095 - NRC Website
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Flowserve with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
WEEKMONTHYEARENS 567642023-09-29T04:00:00029 September 2023 04:00:00
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