ENS Event | |
|---|---|
21:53 Oct 8, 2024 | |
| Title | Part 21 - Degraded Voltage Due to a Loose Terminal Connection Screw |
| Event Description | The following information was provided by the licensee via phone and email:
This is a non-emergency notification submitted in accordance with 10 CFR 21.21(d)(3)(i). A written notification in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 20 days. On October 8, 2024, North Anna Power Station (NAPS) determined a manufacturing defect affecting the normal AC supply molded case switch for the Unit 1, 1-IV battery charger was reportable under Part 21. On July 29, 2024, the 1-IV battery charger was declared inoperable due to the AC input voltage reading approximately 250 VAC on the B-C phases and A-C phases. The A-B phase voltage was normal at 480 VAC. Troubleshooting determined the normal AC supply molded case switch was the cause of the degraded voltage due to a loose terminal connection screw on the 'C' phase load side of the contacts. The NRC Senior Resident Inspector has been notified. Battery Manufacturer: Ametek Solidstate Solutions Switch Manufacturer / Model: Eaton / J250K The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee plans to inspect all battery chargers on both units to verify they don't have loose terminal screws. They are unaware of this issue affecting any other site. |
| Where | |
|---|---|
North Anna  Mineral, Virginia (NRC Region 2) | |
| Organization: | North Anna Power Station |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+19.23 h0.801 days <br />0.114 weeks <br />0.0263 months <br />) | |
| Opened: | Robert Page 17:07 Oct 9, 2024 |
| NRC Officer: | Kerby Scales |
| Last Updated: | Oct 9, 2024 |
| 57370 - NRC Website
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WEEKMONTHYEARENS 573702024-10-08T21:53:0008 October 2024 21:53:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Degraded Voltage Due to a Loose Terminal Connection Screw 2024-10-08T21:53:00 | |