| | Site | Start date | Title | Description |
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| 05000277/LER-2025-001, Invalid Actuation Due to Bus Failure | Peach Bottom | 8 October 2025 | Invalid Actuation Due to Bus Failure | | | 05000259/LER-2025-001, Reactor Scram Due to Low Reactor Water Level | Browns Ferry | 30 September 2025 | Reactor Scram Due to Low Reactor Water Level | | | L-MT-25-031, Site Specific Emergency Action Level Technical Basis Documents Change | Monticello | 24 September 2025 | Site Specific Emergency Action Level Technical Basis Documents Change | | | 05000260/LER-2025-001-01, Reactor Scram Due to Low Electro-Hydraulic Control Pressure | Browns Ferry | 9 September 2025 | Reactor Scram Due to Low Electro-Hydraulic Control Pressure | | | IR 05000277/2025002 | Peach Bottom | 25 July 2025 | Integrated Inspection Report 05000277/2025002 and 05000278/2025002 | | | 05000260/LER-2025-001, Reactor Scram Due to Low Electro-Hydraulic Control Pressure | Browns Ferry | 10 July 2025 | Reactor Scram Due to Low Electro-Hydraulic Control Pressure | | | ML25191A041 | Browns Ferry | 10 July 2025 | Tennessee Valley Authority, 10 CFR 21 Notification -- Defect Associated with Anchor Darling Double-disc Gate Valve | | | ENS 57850 | Browns Ferry | 10 June 2025 23:10:00 | 60-DAY Optional Telephonic Notification for Invalid Containment Isolation | The following information was provided by the licensee via phone and email:
This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system.
On June 10, 2025, Unit 2 operations personnel received an `A' channel half scram and entered 2-AOI-99-1. Motor generator set 2A was shut down and reactor protection system `A' was swapped to alternate. This resulted in primary containment isolation system (PCIS) groups 2, 3, 6, and 8 isolations, and initiation of standby gas treatment (SGT) trains `A', `B', and `C' and control room emergency ventilation system (CREV) train `A'. All affected safety systems responded as expected.
Plant conditions which initiate PCIS groups 2 and 8 actuations are reactor vessel low water level and high drywell pressure. Plant conditions which initiate PCIS group 3 actuations, are reactor vessel low water level and reactor water cleanup area high temperature.
Plant conditions which initiate PCIS group 6, CREV and SGT actuations, are reactor vessel low water level, high drywell pressure, or reactor building ventilation exhaust high radiation (reactor zone or refuel zone). At the time of the event, these conditions did not exist; the actuation was due to a loss of power and not due to a low reactor water level or drywell pressure. Therefore, the actuation of the PCIS, CREV, and SGT was invalid.
Upon investigation, the 2A2 circuit protector was found to have charred wire on the top right lug. The terminal block was replaced.
There were no safety consequences or impact to the health and safety of the public as a result of this event.
This event was entered into the corrective action program as condition report 2019406. | | ENS 57737 | Browns Ferry | 31 May 2025 03:47:00 | Manual Reactor Trip | The following information was provided by the licensee via phone and email:
At 2247 CDT on 5/30/25, with Unit 2 operating in mode 1 at 39 percent reactor power, the reactor was manually tripped due to a trip of the only operating reactor recirculation pump (2B). Approximately 44 minutes prior at 2203 CDT, the 2A reactor recirculation pump tripped.
Operations responded and stabilized the plant. Primary containment isolation systems (PCIS) received an actuation signal for groups 2, 3, 6 and 8 on reactor water level at +2 inches. All primary containment systems that received an actuation signal performed as designed. All other systems functioned as designed. Reactor water level control is via condensate and feedwater, and reactor cooldown is in progress using turbine bypass valves to the main condenser.
Due to the reactor protection system (RPS) actuation while critical, this event is being reported as a four-hour non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). The actuation of RPS and PCIS also requires an eight-hour non-emergency report per 10 CFR 50.72(b)(3)(iv)(A).
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 site reduced power from 100 percent following the loss of the 2A recirculation pump. | | ENS 57840 | Browns Ferry | 30 May 2025 05:00:00 | Invalid Actuation of Primary Containment Isolation System (PCIS) Group 6 | The following information was provided by the licensee via phone and email:
This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system.
On May 30, 2025, during de-inerting of the Unit 2 drywell for a forced outage, Unit 2 received a partial primary containment isolation system (PCIS) group 6 isolation. Additionally, standby gas treatment system (SGT) trains `B' and `C' auto started.
Plant conditions which initiate PCIS group 6 and SGT actuations are reactor vessel low water level (Level 3), high drywell pressure, or reactor building ventilation exhaust high radiation (reactor zone or refuel zone). At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS and SGT was invalid.
Upon investigation, a fuse was found to have failed as a result of a hot spot due to a corroded lug, which was the cause of the isolation. The fuse was replaced, (lug cleaned), condition was cleared, and all systems were realigned as necessary.
There were no safety consequences or impact to the health and safety of the public as a result of this event.
This event was entered into the Corrective Action Program as Condition Report 2017035.
The NRC Resident Inspector has been notified of this event. |
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