ENS 53653: Difference between revisions
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| NRC officer = Ossy Font | | NRC officer = Ossy Font | ||
| event date = 08/07/2018 00:00 EDT | | event date = 08/07/2018 00:00 EDT | ||
| last update date = | | last update date = 05/31/2019 | ||
| title = | | title = Part 21 Notification - Namco Limit Switch Failed Test Due to Insufficient Lubrication | ||
| event text = | | event text = The following information was received via email from Curtiss Wright: | ||
The following information was received via email from Curtiss Wright: | |||
Curtiss-Wright was notified on August 7, 2018 by Exelon's Dresden Plant that a Curtiss-Wright Supplied Namco Limit Switch, P/N: EA700-90964 had failed during a planned maintenance test. | Curtiss-Wright was notified on August 7, 2018 by Exelon's Dresden Plant that a Curtiss-Wright Supplied Namco Limit Switch, P/N: EA700-90964 had failed during a planned maintenance test. | ||
The switch contacts were found to be sluggish in returning to the normal shelf state after actuation, or would not return at all. The switch was identified as Curtiss-Wright Tag Number 5T34603 and was provided as a safety related component to Exelon in September 2005. According to Exelon, the item was stored for 8 years, then failure occurred approximately 5 years into service. The part has a manufacturer date coded as August 2005. | The switch contacts were found to be sluggish in returning to the normal shelf state after actuation, or would not return at all. The switch was identified as Curtiss-Wright Tag Number 5T34603 and was provided as a safety related component to Exelon in September 2005. According to Exelon, the item was stored for 8 years, then failure occurred approximately 5 years into service. The part has a manufacturer date coded as August 2005. | ||
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We therefore request additional time to complete our evaluation and should have our final report issued by May 31, 2019. | We therefore request additional time to complete our evaluation and should have our final report issued by May 31, 2019. | ||
Notified R3DO (Hills) and Part 21/50.55 Reactors group (email). | Notified R3DO (Hills) and Part 21/50.55 Reactors group (email). | ||
| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2019/ | * * * UPDATE AT 1106 EDT ON 5/31/19 FROM MARGIE HOVER TO JEFF HERRERA * * * | ||
The following information was received via e-mail: | |||
ln reference to the Curtiss-Wright Interim Notification Report dated 10/8/2018 (Event No. ML18289A457lLoC No. 2018-24-00) for an EA700-90954 limit switch failure, the following updates are provided. | |||
Curtiss-Wright was notified on August 7th, 2018 by Exelon's Quad Cities Plant that a Curtiss-Wright Supplied Namco Limit Switch, PIN: EA 700-90954 had failed during a planned maintenance test. | |||
CW Conclusion: | |||
Based upon similar wear patterns, the presence of 'significant grease' does not resolve wear pattern issue caused in a shorter period of time, thus the lack of grease can be considered to 'not be a significant credible failure mechanism' (same or no grease between shuttle and housing). Based upon the NAMCO report, the presence or lack of grease has no impact on wear or operability and thus does not affect the safety function. | |||
In addition, the CQ14100801 S/N 03 installed for 9 months, the O-Ring measured an 81 durometer hardness (showing aging) but not brittle. The other 3 installed for 6 years were brittle but did not affect operability. Thus the hardness of the O-Rings can be considered to 'not be a significant credible failure mechanism'. | |||
All four switches in Report QDC-62770 had paint scrapings caused by wear which was present and operated properly after being in service for an extended period of time. Thus the presence of paint residue due to wear can be considered to 'not be a significant credible failure mechanism'. | |||
There have been no other reported failures of this type. The root cause failure mechanism has not been identified, thus this switch failure does not appear to represent a common mode failure. | |||
Notified the R3DO (Daley) and Part 21/50.55 Reactors group (via email). | |||
| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2019/20190603en.html#en53653 | |||
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{{ENS-Nav}} | {{ENS-Nav}} | ||
Latest revision as of 07:30, 4 June 2019
| Where | |
|---|---|
| Curtiss Wright Cincinnati, Ohio (NRC Region 3) | |
| Organization: | Curtiss Wright |
| Reporting | |
| 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
| Time - Person (Reporting Time:+1498.9 h62.454 days <br />8.922 weeks <br />2.053 months <br />) | |
| Opened: | Tim Franchuk 14:54 Oct 8, 2018 |
| NRC Officer: | Ossy Font |
| Last Updated: | May 31, 2019 |
| 53653 - NRC Website | |