ENS Event | |
|---|---|
04:00 Feb 13, 2012 | |
| Title | Part 21 - Steam Generator Tube Wear Adjacent to Retainer Bars |
| Event Description | The following information was received via email:
Mitsubishi Heavy Industries, LTD (MHI) has identified steam generator tube wear for San Onofre Nuclear Generating Station. The Steam Generator tube wear adjacent to the retainer bars was identified as creating a potential safety hazard. The maximum wear depth is 90% of the tube thickness. The cause of the tube wear has been determined to be the retainer bars' random flow-induced vibration caused by the secondary fluid exiting the tube bundle. Since the retainer bar has a low natural frequency, the bar vibrates with a large amplitude. This type tube wear could have an adverse effect on the structural integrity of the tubes, which are part of the pressure boundary. The plugging of the tubes that are adjacent to the retainer bars was performed. MHI has recommended to the purchaser to remove the retainer bars that would have the possibility of vibration with large amplitude or to perform the plugging and stabilizing for the associated tubes. |
| Where | |
|---|---|
| Mitsubishi Heavy Industries, Ltd. Arlington, Virginia (NRC Region 1) | |
| Organization: | Mitsubishi Nuclear Energy Systems |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+5644.28 h235.178 days <br />33.597 weeks <br />7.732 months <br />) | |
| Opened: | Joseph Tapia 07:17 Oct 5, 2012 |
| NRC Officer: | Dong Park |
| Last Updated: | Oct 5, 2012 |
| 48379 - NRC Website | |
Mitsubishi Heavy Industries, Ltd. with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 483802012-02-21T04:00:00021 February 2012 04:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Steam Generator Tube to Tube Wear ENS 483792012-02-13T04:00:00013 February 2012 04:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Steam Generator Tube Wear Adjacent to Retainer Bars 2012-02-21T04:00:00 | |