ENS 57464
ENS Event | |
|---|---|
16:30 Dec 10, 2024 | |
| Title | |
| Event Description | The following information was provided by the licensee via phone and email:
At 0930 CST on 12/10/2024, Arkansas Nuclear One, Unit 1, discovered both isolation valves open in a one-inch breathing air line containment (reactor building) penetration. This resulted in inoperable reactor building isolation valves in a required mode of applicability per Unit 1 Technical Specification 3.6.3 and an inoperable reactor building per Unit 1 Technical Specification 3.6.1. Unit 1 had recently entered the modes of applicability for both Technical Specifications at 0556 CST on 12/8/2024 following a planned maintenance outage. The outside isolation valve was locked closed at 0950 CST on 12/10/2024, restoring operability of the reactor building. The inside valve was locked closed at 1345 CST on 12/10/2024, restoring operability of both isolation valves. This condition is being reported under 10 CFR 50.72(b)(3)(ii)(B) as an event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety. This condition is also being reported under 10 CFR 50.72(b)(3)(v)(C) and (D) as an event or condition that, at the time of discovery, could have prevented the fulfillment of the safety function of structures or systems that are needed to: (C) Control the release of radioactive material; or (D) Mitigate the consequences of an accident. There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The cause of the out-of-position valves is under investigation. No evolutions were in progress besides a plant startup at the time of the event. |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+1.53 h0.0638 days <br />0.00911 weeks <br />0.0021 months <br />) | |
| Opened: | John Lindsey 18:02 Dec 10, 2024 |
| NRC Officer: | Jordan Wingate |
| Last Updated: | Dec 10, 2024 |
| 57464 - NRC Website
Loading map... {"minzoom":false,"maxzoom":false,"mappingservice":"leaflet","width":"350px","height":"250px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"zoom":6,"defzoom":14,"layers":["OpenStreetMap"],"image layers":[],"overlays":[],"resizable":false,"fullscreen":false,"scrollwheelzoom":true,"cluster":false,"clustermaxzoom":20,"clusterzoomonclick":true,"clustermaxradius":80,"clusterspiderfy":true,"geojson":"","clicktarget":"","imageLayers":[],"locations":[{"text":"\u003Cb\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003E\u003Ca class=\"mw-selflink selflink\"\u003EENS 57464\u003C/a\u003E - \u003Ca href=\"/Arkansas_Nuclear\" title=\"Arkansas Nuclear\"\u003EArkansas Nuclear\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003ESecondary Containment Inoperable\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 57464 - Arkansas Nuclear\n","link":"","lat":35.31055555555555,"lon":-93.23084444444444,"icon":"/w/images/7/79/Entergy_icon.png"}],"imageoverlays":null} | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (67 %) |
| After | Power Operation (100 %) |