Secondary Containment is the last barrier to stop the release of radiological material. It is typically called the Reactor Building
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| | Site | Start date | Title | Description |
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| ENS 57464 | Arkansas Nuclear | 10 December 2024 16:30:00 | Secondary Containment Inoperable | 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. | | ENS 57454 | Unswick | 4 December 2024 21:40:00 | Secondary Containment Inoperable | The following information was provided by the licensee via phone and email:
At 1640 EST, on December 4, 2024, secondary containment was declared inoperable. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C), as an event or condition that could have prevented fulfillment of a safety function.
Secondary containment was declared inoperable due to a small hole discovered in the service water piping within secondary containment. The effective safety function was restored at 1730 EST by installation of a temporary repair and secondary containment has been restored to operable.
There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector has been notified.
Notified R2DO (Suber) | | IR 05000263/2024003 | Monticello | 13 November 2024 | Integrated Inspection Report 05000263/2024003 | | | IR 05000336/2024003 | Millstone
Calvert Cliffs | 7 November 2024 | Integrated Inspection Report 05000336/2024003 and 05000423/2024003 and Apparent Violation and Independent Spent Fuel Storage Installation Inspection Report 07200008/2024001 | | | IR 05000416/2024003 | Grand Gulf | 6 November 2024 | Integrated Inspection Report 05000416/2024003 | | | IR 05000341/2024003 | Fermi | 6 November 2024 | Integrated Inspection Report 05000341/2024003 | | | IR 05000298/2024003 | Cooper | 5 November 2024 | Integrated Inspection Report 05000298/2024003 | | | RS-24-101, License Amendment Request for One-Time Extension of Standby Gas Treatment System Technical Specifications Completion Time to Support Piping Repair | Quad Cities | 4 November 2024 | License Amendment Request for One-Time Extension of Standby Gas Treatment System Technical Specifications Completion Time to Support Piping Repair | | | ML24151A384 | Limerick | 31 October 2024 | – Issuance of Amendment Nos. 264 and 226 Support to Digital Modernization Project Installation (EPID L-2023-LLA-0025) and Exemption from the Requirements of 10 CFR 50.62 | | | ML22199A257 | | 30 October 2024 | DG-5075 - Establishing Cybersecurity Programs for Commercial Nuclear Plants Licensed Under 10 CFR Part 53 | |
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