ENS Event | |
|---|---|
05:00 Apr 17, 2012 | |
| Title | Part 21 Report - Swagelok U Series Bellows Valves Loosening of Stem Tips |
| Event Description | Swagelok received a return from Duke Energy (Oconee) for two 8U series bellows valves for investigation of stem tips that had loosened during performance testing of equipment.
Our evaluation confirmed loosening of the stem tips and determined the root cause to be higher than normal torque being applied to the valve handle during closure. (Please note that we did not specify a minimum or maximum torque for our operating instructions). This caused the stem and the stem insert interface to loosen, but not fully disengage. Our tests show that closure to catalog specification of 4.0 x 10-9 atm. cc/sec of helium can still be achieved with this condition. Therefore, it is the opinion of Swagelok that there is no inherent safety risk associated due to this condition, however lower than expected flow through the valve, or erratic flow, can occur if the stem tip loosens. If utilities consider full flow as a safety function, they should evaluate the valves currently in service for this condition. Applicability - There have been no other field returns for this condition. The possible condition extends to the Swagelok 4U, 6U and 8U series bellows valves. Only hand operated valves are susceptible; air operated valves are excluded, as are the 12U series valves supplied by Swagelok. Callaway may also be affected and will be notified by the Supplier. |
| Where | |
|---|---|
| Swagelok Company (NRC Region) | |
| Organization: | Swagelok Company |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+8.85 h0.369 days <br />0.0527 weeks <br />0.0121 months <br />) | |
| Opened: | Bruce Flusche 13:51 Apr 17, 2012 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Apr 17, 2012 |
| 47842 - NRC Website | |
Swagelok Company with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 478422012-04-17T05:00:00017 April 2012 05:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Report - Swagelok U Series Bellows Valves Loosening of Stem Tips 2012-04-17T05:00:00 | |