ENS 57304
ENS Event | |
|---|---|
23:09 Sep 4, 2024 | |
| Title | Part 21 - Stress Corrosion Cracking in Control Rod Blades |
| Event Description | The following information was provided by Westinghouse Electric Company via phone and email:
This issue concerns the Westinghouse designed and manufactured CR99 and Trident X boiling water reactor (BWR) control rod blades (CRBs). The CR99 CRBs were designed with dimensional and material choices for mechanical stability such that the mechanical function is maintained throughout the life of the control rod. However, observed cracking at United States licensees, resulting from irradiation assisted stress corrosion cracking (IASCC), occurred before the nuclear end of life. Therefore, the current depletion limits that define nuclear end of life are not sufficient to prevent cracking, and the continued use of uninspected CRBs can lead to further cracking. With severe cracking of the CRBs, boron loss can occur and negatively impact the shutdown margin. Westinghouse is aware that plants which experienced CRB cracking have been able to scram their cracked CRBs, safely shut down the reactor, and maintain it in a safe shutdown condition. Trident X CRBs are susceptible to IASCC and within the scope of this notification. However, the first Trident X CRBs were installed in a US operating plant earlier in 2024 and have operated for less than one cycle. Westinghouse continues to communicate with impacted licensees and will issue plant-specific operating recommendations. Operating Plants with Generation 2 and 3 CR99 CRBs Brunswick Units 1 and 2, Dresden Unit 3, Hatch Units 1 and 2, Hope Creek, La Salle Unit 1, Nine Mile Point Unit 2, Quad Cities Unit 1, Susquehanna Units 1 and 2 Permanently Shutdown/Decommissioned Plants with Generation 2 and 3 CR99 CRBs Duane Arnold Operating Plants with Trident x CRBs Brunswick Unit 1 Point of Contract: Camille Zozula Manager, Global Nuclear Regulatory Affairs Westinghouse Electric Company LLC 412-374-2577 zozulact@westinghouse.com |
| Where | |
|---|---|
| Westinghouse Electric Company Cranberry Township, Pennsylvania (NRC Region 1) | |
| Organization: | Westinghouse Electric Company |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+-4.3 h-0.179 days <br />-0.0256 weeks <br />-0.00589 months <br />) | |
| Opened: | Camille Zozula 18:51 Sep 4, 2024 |
| NRC Officer: | Natalie Starfish |
| Last Updated: | Sep 4, 2024 |
| 57304 - NRC Website | |
Westinghouse Electric Company with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 573042024-09-04T23:09:0004 September 2024 23:09:00
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