ENS Event | |
|---|---|
04:00 Oct 24, 2009 | |
| Title | Potential Aggressive Wearing of Rod Cluster Control Assembly Guide Cards |
| Event Description | Aggressive wearing of the RCCA [Rod Cluster Control Assembly] guide card has been observed at an international plant. Such aggressive wear has not been observed in any US plants. If this issue were to remain uncorrected, it is possible for enough wear to occur during the life of the plant that the RCCAs could become unguided and may not properly insert into the core. It has not been concluded whether there is a safety hazard which would result from this deviation.
Aggressive wearing of the Rod Cluster Control Assembly (RCCA) guide card has been observed at an international plant. Such aggressive wear has not been observed in any other plants. If this issue were to remain uncorrected, it was postulated that enough wear could occur during the life of the plant that the RCCAs could become unguided and may not properly insert into the core. With the exception of the one international plant in which abnormal excessive wear has been found, the conclusion from the analysis of the collection of wear data and the analysis of rodlet insertion with worn guide cards is that there is no concern for safe operation of any plant regarding guide tube wear for the 40-year design life. The engineering analysis supports this conclusion regardless of the type of RCCA guide tube or the RCCA rodlet material currently in use. For the international plant with the excessive wear, years of continued safe operation is available, and a justification for continued operation has been provided to the utility. Directives in Materials Reliability Program (MRP 227) will necessitate guide tube inspections as part of life extension licensing. Concerning AP 1000, a guide tube wear analysis has been performed. The analysis demonstrates operability for the 60-year design life for the shutdown control rods. Based on the above evaluation results, it has been determined that this issue does not represent a substantial safety hazard pursuant to the requirements delineated in I0CFR Part 21 . |
| Where | |
|---|---|
| Westinghouse Electric Company Pittsburgh, Pennsylvania (NRC Region 1) | |
| Organization: | Westinghouse Electric Company |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+8.18 h0.341 days <br />0.0487 weeks <br />0.0112 months <br />) | |
| Opened: | J. A. Gresham 12:11 Oct 24, 2009 |
| NRC Officer: | Vince Klco |
| Last Updated: | Jan 14, 2010 |
| 45465 - NRC Website | |
Westinghouse Electric Company with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 454652009-10-24T04:00:00024 October 2009 04:00:00
[Table view]10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Potential Aggressive Wearing of Rod Cluster Control Assembly Guide Cards 2009-10-24T04:00:00 | |