ENS 53856
ENS Event | |
|---|---|
06:00 Dec 8, 2018 | |
| Title | Part 21 - Notification of Deviation of Switches with Terminal Blocks |
| Event Description | The following was received via fax and email from SOR:
Exelon Limerick generating station notified SOR on December 8, 2018 via email regarding corrective action needed for the R-series housing on two of their emergency diesel engines. Limerick reported that the field wire lugs were in close contact with the switch cover gasket and had degraded the EPR (Ethylene Propylene Rubber) housing cover material enough to short to the cover which, in turn, tripped the 1A control fuse. Limerick reported that the uninsulated terminals and wiring were already available at the switch location during installation and used without modification. Limerick's immediate corrective action was to land the field wiring on the bottom tier of the terminal block and insulate the lugs. EPR is known to be an effective electrical insulator, and is used as insulation for many electrical cables. For this reason, the EPR cover gasket was used on the SOR R-series nuclear housing to offer sufficient electrical insulation. Due to the failure at the Limerick generating station and subsequent evaluation at SOR, the EPR gasket alone does not provide sufficient electrical insulation between the terminal block connections and the metallic housing cover when uninsulated terminals are installed. This direct connection will cause heating of the gasket and eventual direct short through the EPR material. SOR does not have the capability to perform further evaluations to determine if a safety hazard exists as the specific customer installation practices is unknown. The end user must confirm for each application the wire installation applied with this specific model string. The plants who are potentially affected by this deviation are in the process of being notified by email and/or postal letter and are: - Callaway - Braidwood - Byron - Limerick - Quad Cities - Davis Besse - St. Lucie - H.B. Robinson SOR has completed or is implementing the following corrective actions: - Completed the identification of the customers potentially affected by this deviation within this notification - Initiated customer complaint 21 and corrective action (CAR) 1003 - Released ECO 5443 to add 3.5" wide Nomex insulation paper to the terminal block units - Created a modified cover gasket with a Kapton insulation piece for field units - Revision to SOR General Instruction to require customers to use insulated terminal connections targeting completion by February 28, 2019 - Investigate modification to SOR insulation resistance and dielectric tests targeting completion by February 28, 2019 Should you have any additional questions regarding this matter, please contact: For general inquiries: Linda Coutts Inside Sales Representative Email: lcoutts@sorinc.com Tel 913-956-3071 For technical inquiries: Mike Bequette Vice President of Engineering Email: mbeguette@sorinc.com Tel 913-956-3040 Sara Roos Senior Engineer Email: sroos@sorinc.com Tel 913-956-3049 |
| Where | |
|---|---|
| Sor Lenexa, Kansas (NRC Region 4) | |
| Organization: | Sor |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+1327.88 h55.328 days <br />7.904 weeks <br />1.819 months <br />) | |
| Opened: | Melanie Dirks 13:53 Feb 1, 2019 |
| NRC Officer: | Ossy Font |
| Last Updated: | Feb 1, 2019 |
| 53856 - NRC Website | |
Sor with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 538562018-12-08T06:00:0008 December 2018 06:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Notification of Deviation of Switches with Terminal Blocks ENS 523592016-11-03T06:00:0003 November 2016 06:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Notification of Deviation - Sor Qualification Test Report 9058-102 2018-12-08T06:00:00 | |