ENS Event | |
|---|---|
04:00 Feb 21, 2012 | |
| Title | Steam Generator Tube to Tube Wear |
| 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. Steam Generator tube wear has been identified in areas of the U-bend between anti-vibration bars, where the tube is not supported by the anti-vibration bars. This tube wear occurred due to the contact of a tube with an adjacent tube, and resulted in a leak from a Unit 3 tube. The cause of the tube leak was determined to be the in-plane direction fluid elastic instability under high localized thermal-hydraulic conditions (steam quality (void fraction), flow velocity and hydro-dynamic pressure), and insufficient contact force of the tube to anti-vibration bar. This type Mitsubishi Heavy Industries 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 plugging of the tubes that have the possibility of the fluid elastic instability and thermal power output reductions were identified as potential corrective actions. SCE [Southern California Edison] will run Unit 2 at 70% power for a short duration as a corrective action. In addition, SCE and MHI will continue a detailed analysis and investigation to this problem. Additional corrective actions may be required as the analysis and investigation continue. MHI has recommended to the purchaser that it perform eddy current inspection of tubes after Unit 2 operation resumes. |
| 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:+5452.28 h227.178 days <br />32.454 weeks <br />7.469 months <br />) | |
| Opened: | Joseph Tapia 07:17 Oct 5, 2012 |
| NRC Officer: | Dong Park |
| Last Updated: | Oct 5, 2012 |
| 48380 - 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 | |