ENS Event | |
|---|---|
19:31 Oct 8, 2024 | |
| Title | Degraded Condition |
| Event Description | The following information was provided by the licensee via phone and email:
At 1431 CDT, on October 8, 2024, Arkansas Nuclear One, Unit 2 (ANO-2) completed the analysis related to an indication revealed on head penetration '71' during reactor vessel closure head inspections. It was determined that the indication is not acceptable under the American Society of Mechanical Engineers (ASME) code requirements. The indication displays characteristics of abnormal degradation of a barrier that requires taking corrective actions to ensure the barriers capability. No leak path signal was identified during ultrasonic testing or bare metal visual inspections. The plant was in cold shutdown at zero percent power and defueled for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. This is the only indication that is currently present; however, if additional indications are found, they will also be repaired prior to the plant startup. The NRC Senior Resident Inspector has been notified. |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| LER: | 05000368/LER-2024-001 Surface Flaw in Primary Coolant System |
| Time - Person (Reporting Time:+-1.32 h-0.055 days <br />-0.00786 weeks <br />-0.00181 months <br />) | |
| Opened: | Keith Duke 18:12 Oct 8, 2024 |
| NRC Officer: | Brian P. Smith |
| Last Updated: | Oct 8, 2024 |
| 57369 - NRC Website
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WEEKMONTHYEARENS 573692024-10-08T19:31:0008 October 2024 19:31:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition ENS 555062021-10-04T19:33:0004 October 2021 19:33:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Discovered on Reactor Vessel Head Penetration ENS 534562018-06-12T20:00:00012 June 2018 20:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressure Boundary Leakage Identified While Shutdown ENS 457972010-03-27T20:31:00027 March 2010 20:31:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Potentially Degraded Pressurizer Level Tap Identified ENS 414732005-03-09T11:37:0009 March 2005 11:37:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressurizer Heater Sleeve Leakage ENS 407212004-04-30T19:38:00030 April 2004 19:38:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded "on 4/30/2004, During Refueling Outage 1 R18, Ultrasonic Testing of the Reactor Vessel Head Identified Two Axial Indications on Control Rod Drive Mechanism, Nozzle 61. the Indications Were Located on the Outside Diameter of the Nozzle on the Lower Hillside. One of the Flaws Was at the Toe of the Fillet Weld and Extended Below the Fillet Weld Cap. the Second Flaw Extended the Full Length of the Weld and Just Below the Toe of the Fillet Weld. ENS 402162003-10-02T22:15:0002 October 2003 22:15:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Rcs Boundary Leakage Due to Small Crack on Drain Line Welded Cap 2024-10-08T19:31:00 | |