Licensee Event Report

If a criteria is reached according to NUREG-1022 then a Licensee to the NRC must submit a Licensee Event Report to explain what happened.

Reporting Criteria

• 10 CFR 50.73(a)(1), Submit an LER
• 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown
• 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications (Text"Text" is a predefined property that represents text of arbitrary length and is provided by Semantic MediaWiki.: Any operation or condition which was prohibited by the plant's Technical Specifications)
• 10 CFR 50.73(a)(2)(i)(C), 50.54(x) TS Deviation
• 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded
• 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
• 10 CFR 50.73(a)(2)(iv)(A), System Actuation
• 10 CFR 50.73(a)(2)(iv), System Actuation
• 10 CFR 50.73(a)(2)(ix)(A), Prevented Safety Function in Multiple System
• 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor
• 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat
• 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material
• 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
• 10 CFR 50.73(a)(2)(v), Loss of Safety Function
• 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability

Writing LERs

Explain exactly what happened during the entire event or condition, including how systems, components, and operating personnel performed. Do not cover specific hardware problems in excessive detail. Describe unique characteristics of a plant as well as other characteristics that influenced the event (favorably or unfavorably).

• Avoid using plant-unique terms and abbreviations, or, as a minimum, clearly define them.
  • The audience for LERs is large and does not necessarily know the details of each plant.
• Include the root causes, the plant status before the event, and the sequence of occurrences.
• Describe the event from the perspective of the Operator (i.e., what the operator saw, did, perceived, understood, or misunderstood).
• If several systems actuate during an event, describe all aspects of the complete event, including all actuations sequentially, and those aspects that by themselves would not be reportable.
  • For example, if a single component failure (generally not reportable) occurs following a reactor scram (reportable), describe the component failure in the narrative of the LER for the reactor scram.
• It is necessary to discuss the performance and status of equipment.
• Paraphrase pertinent sections of the latest submitted Safety analysis report (SAR) rather than referencing them because not all organizations or individuals have access to SARs.
• Extensive cross-referencing would be time consuming considering the large number of LERs and reviewers that read each LER.
• Ensure that each component's safety-significant effect on the event or condition is clearly and completely described.
• Do not use statements such as "this event is not significant with respect to the health and safety of the public" without explaining the basis for the conclusion.

Specific information that should be included, as appropriate, is described in paragraphs 50.73(b).

Submissions of LERs

Section 50.73(d) of the NUREG-1022 states that submmissions must be done with Form NRC 366 as described by section 50.4. Submissions are to be done within 60 days of the event. If that happens to be a weekend or a holiday then it must be the next working day. If a Licensee knows that a report will be late or needs an additional day or so to complete the report, the situation should be discussed with the appropriate NRC regional office. See Section 2.5 for further discussion of discovery date.

LER Forwarding Letter and Cancellations

The cover letter forwarding an LER to the NRC should be signed by a responsible official. There is no prescribed format for the letter. The date the letter is issued and the report date should be the same. Licensees are encouraged to include the NRC resident inspector and the Institute of Nuclear Power Operations (INPO) in their distribution. Multiple LERs can be forwarded by one forwarding letter. Cancellations of LERs submitted should be made by letter. The letter should state that the LER is being canceled (i.e., formally withdrawn). The bases for the cancellation should be explained so that the staff can understand and review the reasons supporting the determination. The notice of cancellation will be filed and stored with the LER and acknowledgement made in various automated data systems. The LER will be removed from the LER data base.

Voluntary LERs

Indicate information-type LERS (i.e., Voluntary LERs) by checking the "Other" block in Item 11 of the LER form and type "Voluntary Report" in the space immediately below the block. Also give a sequential LER number to the voluntary report as noted in Section 5.2.4(5). Because not all requirements of 50.73(b), "Contents," may pertain to some voluntary reports, licensees should develop the content of such reports to best present the information associated with the situation being reported. See Section 2.7 for additional discussion of Voluntary LERs.

How To Find LERs

• NRC Website search - Good for industry searching of LERs

See also

• NRC Form 366, Licensee Event Report - the NRC form
• NUREG-1022, Event Reporting Guidelines for 10 CFR 50.72 and 10 CFR 50.73

LER list

by site

1 year

Site	#	Company	Event lists
Almaraz	0	Iberdrola	[Almaraz events]	[RSS]
Arkansas Nuclear	0	Entergy	[Arkansas Nuclear events]	[RSS]
Asco	0	Endesa	[Asco events]	[RSS]
Beaver Valley	0	Vistra	[Beaver Valley events]	[RSS]
Belleville	0	Électricité de France	[Belleville events]	[RSS]
Big Rock Point	0	Consumers Energy	[Big Rock Point events]	[RSS]
Blayais	0	Électricité de France	[Blayais events]	[RSS]
Braidwood	0	Constellation	[Braidwood events]	[RSS]
Browns Ferry	0	Tennessee Valley Authority	[Browns Ferry events]	[RSS]
Brunswick	0	Duke Energy	[Brunswick events]	[RSS]
Byron	0	Constellation	[Byron events]	[RSS]
Callaway	0	Ameren	[Callaway events]	[RSS]
Calvert Cliffs	0	Constellation	[Calvert Cliffs events]	[RSS]
Catawba	0	Duke Energy	[Catawba events]	[RSS]
Chernobyl	0		[Chernobyl events]	[RSS]
Clinch River	0		[Clinch River events]	[RSS]
Clinton	0	Constellation	[Clinton events]	[RSS]
Cofrentes	0	Iberdrola	[Cofrentes events]	[RSS]
Columbia	0	Energy Northwest	[Columbia events]	[RSS]
Comanche Peak	0	Luminant	[Comanche Peak events]	[RSS]
Cook	0	American Electric Power	[Cook events]	[RSS]
Cooper	0	Entergy	[Cooper events]	[RSS]
Crane	0	Constellation	[Crane events]	[RSS]
Crystal River	0	Duke Energy	[Crystal River events]	[RSS]
Dampierre	0	Électricité de France	[Dampierre events]	[RSS]
Davis Besse	0	Cleveland Electric	[Davis Besse events]	[RSS]
Diablo Canyon	0	Pacific Gas & Electric	[Diablo Canyon events]	[RSS]
Dresden	0	Constellation	[Dresden events]	[RSS]
Duane Arnold	0	NextEra Energy	[Duane Arnold events]	[RSS]
Dungeness	0	EDF Energy	[Dungeness events]	[RSS]
Elk River	0		[Elk River events]	[RSS]
Farley	0	Southern Nuclear	[Farley events]	[RSS]
Fermi	0	DTE Energy	[Fermi events]	[RSS]
FitzPatrick	0	Constellation	[FitzPatrick events]	[RSS]
Flamanville	0	Électricité de France	[Flamanville events]	[RSS]
Fort Calhoun	0	Omaha Public Power District	[Fort Calhoun events]	[RSS]
Fort Saint Vrain	0	Xcel Energy	[Fort Saint Vrain events]	[RSS]
Fukushima Dai-Ichi	0	TEPCO	[Fukushima Dai-Ichi events]	[RSS]
Ginna	0	Constellation	[Ginna events]	[RSS]
Grand Gulf	0	Entergy	[Grand Gulf events]	[RSS]
Haddam Neck	0	Connecticut Yankee Atomic Power Co	[Haddam Neck events]	[RSS]
Hallam	0		[Hallam events]	[RSS]
Harris	0	Duke Energy	[Harris events]	[RSS]
Hartlepool	0	EDF Energy	[Hartlepool events]	[RSS]
Hatch	0	Southern Nuclear	[Hatch events]	[RSS]
Heysham	0	EDF Energy	[Heysham events]	[RSS]
Hinkley Point	0	EDF Energy	[Hinkley Point events]	[RSS]
Hope Creek	0	PSEG	[Hope Creek events]	[RSS]
Humboldt Bay	0	Pacific Gas and Electric	[Humboldt Bay events]	[RSS]
Hunterston	0	EDF Energy	[Hunterston events]	[RSS]
Indian Point	0	Entergy	[Indian Point events]	[RSS]
Jose Cabrera	0	Enresa	[Jose Cabrera events]	[RSS]
Kemmerer	0	TerraPower	[Kemmerer events]	[RSS]
Kewaunee	0	Dominion	[Kewaunee events]	[RSS]
Khmelnytskyi	0	Energoatom	[Khmelnytskyi events]	[RSS]
La Crosse	0	Dairyland Power Cooperative	[La Crosse events]	[RSS]
LaSalle	0	Constellation	[LaSalle events]	[RSS]
Lee	0	Duke Energy	[Lee events]	[RSS]
Limerick	0	Constellation	[Limerick events]	[RSS]
Maine Yankee	0	Maine Yankee	[Maine Yankee events]	[RSS]
McGuire	0	Duke Energy	[McGuire events]	[RSS]
Millstone	0	Dominion	[Millstone events]	[RSS]
Monticello	0	Xcel Energy	[Monticello events]	[RSS]
Nine Mile Point	0	Constellation	[Nine Mile Point events]	[RSS]
Nogent	0	Électricité de France	[Nogent events]	[RSS]
North Anna	0	Dominion	[North Anna events]	[RSS]
Oconee	0	Duke Energy	[Oconee events]	[RSS]
Olkiluoto	0	Teollisuuden Voima	[Olkiluoto events]	[RSS]
Oyster Creek	0	Holtec	[Oyster Creek events]	[RSS]
Palisades	0	Entergy	[Palisades events]	[RSS]
Palo Verde	0	Arizona Public Service	[Palo Verde events]	[RSS]
Parr	0		[Parr events]	[RSS]
Peach Bottom	0	Constellation	[Peach Bottom events]	[RSS]
Perry	0	FirstEnergy	[Perry events]	[RSS]
Pilgrim	0	Holtec	[Pilgrim events]	[RSS]
Point Beach	0	NextEra Energy	[Point Beach events]	[RSS]
Prairie Island	0	Xcel Energy	[Prairie Island events]	[RSS]
Quad Cities	0	Constellation	[Quad Cities events]	[RSS]
Rancho Seco	0	Sacramento Municipal Utility District	[Rancho Seco events]	[RSS]
River Bend	0	Entergy	[River Bend events]	[RSS]
Rivne	0	Energoatom	[Rivne events]	[RSS]
Robinson	0	Duke Energy	[Robinson events]	[RSS]
Saint Lucie	0	NextEra Energy	[Saint Lucie events]	[RSS]
Salem	0	PSEG	[Salem events]	[RSS]
San Onofre	0	Southern California Edison	[San Onofre events]	[RSS]
Santa Maria De Garona	0	Nuclenor	[Santa Maria De Garona events]	[RSS]
Saxton	0	GPU Nuclear	[Saxton events]	[RSS]
Seabrook	0	NextEra Energy	[Seabrook events]	[RSS]
Sequoyah	0	Tennessee Valley Authority	[Sequoyah events]	[RSS]
Shippingport	0		[Shippingport events]	[RSS]
Shoreham	0	Long Island Lighting Company	[Shoreham events]	[RSS]
Sizewell	0	EDF Energy	[Sizewell events]	[RSS]
South Texas	0	STP Nuclear Operating Company	[South Texas events]	[RSS]
South Ukraine	0	Energoatom	[South Ukraine events]	[RSS]
Summer	0	South Carolina Electric & Gas Company	[Summer events]	[RSS]
Sundesert	0	San Diego Gas & Electric Compnay	[Sundesert events]	[RSS]
Surry	0	Dominion	[Surry events]	[RSS]
Susquehanna	0	Talen Energy	[Susquehanna events]	[RSS]
Taishan	0	China Guangdong Nuclear Power Group	[Taishan events]	[RSS]
Trillo	0	Iberdrola	[Trillo events]	[RSS]
Trojan	0	Portland General Electric	[Trojan events]	[RSS]
Turkey Point	0	NextEra Energy	[Turkey Point events]	[RSS]
Vandellos	0	Endesa	[Vandellos events]	[RSS]
Vermont Yankee	0	NorthStar Vermont Yankee	[Vermont Yankee events]	[RSS]
Victoria	0	Exelon	[Victoria events]	[RSS]
Vogtle	0	Southern Nuclear	[Vogtle events]	[RSS]
Waterford	0	Entergy	[Waterford events]	[RSS]
Watts Bar	0	Tennessee Valley Authority	[Watts Bar events]	[RSS]
Wolf Creek	0	Wolf Creek Nuclear Operating Corporation	[Wolf Creek events]	[RSS]
Yankee Rowe	0		[Yankee Rowe events]	[RSS]
Zaporizhzhia	0	Enerhodar	[Zaporizhzhia events]	[RSS]
Zion	0	ZionSolutions	[Zion events]	[RSS]

	Site	Start date	Reporting criterion	System	Topic
05000263/LER-2025-003, Condition Prohibited by Technical Specifications for Not Implementing Setpoint Change of Primary Containment Isolation Valve	Monticello	18 June 2036	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Primary containment
05000325/LER-2026-004, (Bsep), Unit 1, Two Main Steam Line Safety Relief Valves Inoperable	Brunswick	10 September 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Reactor Coolant System Main Steam Line Safety Relief Valve	Time of Discovery Corrosion bonding
05000370/LER-2026-001-01, Reactor Coolant System Pressure Boundary Degraded Due to Through-Wall Flaw	Mcguire	3 September 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded	Steam Generator Reactor Coolant System	Boric Acid Non-Destructive Examination VT-2 Intergranular Stress Corrosion Cracking Liquid penetrant Pressure Boundary Leakage Operational leakage
05000325/LER-2026-003, Loss of Power Instrumentation Inoperable	Brunswick	31 August 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Emergency Diesel Generator
05000461/LER-2026-003-01, Division 3 Switchgear Heat Removal System Head Pressure Controller Non-Functional	Clinton	26 August 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Service water Reactor Core Isolation Cooling High Pressure Core Spray Core Spray Automatic Depressurization System Low Pressure Coolant Injection	Fuel cladding
05000461/LER-2026-004-01, Division 3 Switchgear Heat Removal System Head Pressure Controller Non-Functional	Clinton	26 August 2026
05000341/LER-2026-002, Automatic Reactor Scram Following Bus 101 Lockout Caused by Faulted Abandoned Switchyard Conductor	Fermi	25 August 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	High Pressure Coolant Injection Reactor Protection System Emergency Diesel Generator Reactor Core Isolation Cooling Primary containment Reactor Pressure Vessel Decay Heat Removal Main Condenser Control Rod Main Steam	Unanalyzed Condition Loss of Offsite Power
05000382/LER-2026-001, Dry Cooling Tower B Automatic Isolation Due to Level Switch Failure	Waterford	17 August 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Safe Shutdown Ultimate heat sink Past operability
05000382/LER-2026-002, Essential Chiller B Compressor Motor Junction Box Arcing Resulting in Inoperability	Waterford	17 August 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Ultimate heat sink Enforcement Discretion
05000499/LER-2026-001, Unplanned Automatic Reactor Trip and Turbine Trip Due to Main and Auxiliary Transformer Lockout, Followed by Auxiliary Feedwater Actuation	South Texas	13 August 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B)(8)	Steam Generator Feedwater Reactor Protection System Emergency Diesel Generator Auxiliary Feedwater Main Transformer	Loss of Offsite Power
05000454/LER-2026-002-01, Loss of Automatic Function Identified on Both Trains of Control Room Ventilation Temperature Control	Byron	6 August 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Reactor Coolant System	Past operability
05000250/LER-2026-001, Intermediate Range Neutron Flux Channel Inoperable with Technical Specification Completion Time Exceeded During Startup	Turkey Point	30 July 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
05000336/LER-2026-001, Technical Specification Required Shutdown Due to Dropped Control Element Assembly	Millstone	28 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown	Reactor Coolant System Reactor Protection System Control Rod	Downpower
05000336/LER-2026-002, Manual Reactor Trip Due to a Dropped Control Element Assembly	Millstone	28 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Coolant System Reactor Protection System Control Rod
05000395/LER-2026-003-01, Main Steam Isolation Valve Failed to Close in Mode 3	Summer	21 July 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Main Steam Isolation Valve
05000395/LER-2025-004-01, Actuation of the Reactor Protection and Emergency Feedwater Systems	Summer	21 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Steam Generator Feedwater Emergency Feedwater System
05000341/LER-2026-001, Manual Reactor Scram Due to Isophase Bus Duct Fire	Fermi	17 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(ix)(A), Prevented Safety Function in Multiple System 10 CFR 50.73(a)(2)(viii)(B)	Reactor Protection System Decay Heat Removal Main Condenser Control Rod Main Steam	Unanalyzed Condition
05000461/LER-2026-003, Division 3 Switchgear Heat Removal System Head Pressure Controller Non-Functional	Clinton	16 July 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Service water Reactor Core Isolation Cooling High Pressure Core Spray Core Spray Automatic Depressurization System Low Pressure Coolant Injection	Fuel cladding
05000373/LER-2026-001, Common Emergency Diesel Generator Declared Inoperable Due to Room Temperature Controller Failure	LaSalle	16 July 2026	10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor	Emergency Diesel Generator Core Spray	Mission time
05000461/LER-2026-004, Division 3 Switchgear Heat Removal System Head Pressure Controller Non-Functional	Clinton	16 July 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Service water Reactor Core Isolation Cooling High Pressure Core Spray Core Spray Automatic Depressurization System Low Pressure Coolant Injection	Fuel cladding
05000416/LER-2026-004, Manual Actuation of Standby Service Water System Due to an Open Safety Relief Valve	Grand Gulf	13 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Service water Residual Heat Removal Safety Relief Valve	Safe Shutdown Ultimate heat sink
05000458/LER-2026-002-01, Radioactive Material Lost in Transit	River Bend	9 July 2026
05000259/LER-2026-001, Cancellation LER 2026-001-00 for Browns Ferry Nuclear Plant, Unit 1, Safety System Functional Failure Due to High Pressure Coolant Injection Drain Valves Inoperable	Browns Ferry	9 July 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	High Pressure Coolant Injection
05000416/LER-2026-003, Automatic Emergency Diesel Generator Actuation Caused by Grid Transient	Grand Gulf	6 July 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Emergency Diesel Generator
05000259/LER-2026-003, Residual Heat Removal Pump Motor Inoperable Due to Elevated Lubricating Oil Particulates	Browns Ferry	1 July 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Core Spray Residual Heat Removal Automatic Depressurization System Emergency Core Cooling System Low Pressure Coolant Injection	Safe Shutdown Time of Discovery Past operability Operability Determination
05000282/LER-2025-001-01, Reactor Trip and Auto-Start Actuation of Auxiliary Feedwater Due to Bus 11 Undervoltage Relay Issues	Prairie Island	30 June 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater Decay Heat Removal	Undervoltage Relay
05000327/LER-2026-001, Inoperable Containment Spray Train Results in Condition Prohibited by Technical Specifications	Sequoyah	30 June 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Containment Spray	Safe Shutdown Past operability Biofouling Flow Induced Vibration
05000498/LER-2026-001, Automatic Actuation of Emergency Diesel Generator Due to Lockout of Switchyard Electrical Bus	South Texas	29 June 2026	10 CFR 50.73(a)(2)(iv)(B)(8)	Emergency Diesel Generator Auxiliary Feedwater	Loss of Offsite Power Lightning
05000395/LER-2026-001-01, Operations Prohibited by Technical Specifications	Summer	26 June 2026	10 CFR 50.73(a)(1), Submit an LER 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Feedwater
05000354/LER-2026-001-01, Loss of Offsite Power Resulting in Automatic Reactor Scram, Valid System Actuations, Operation in a Condition Prohibited by Technical Specifications, and a Condition That Could Have Prevented.	Hope Creek	24 June 2026		High Pressure Coolant Injection Emergency Diesel Generator Main Steam Isolation Valve Reactor Core Isolation Cooling Safety Relief Valve Control Rod	Loss of Offsite Power
05000461/LER-2025-001-01, MSIV B21-F022D Limit Switch Failed Testing	Clinton	23 June 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Reactor Protection System Main Steam Line Main Steam	Operability Determination
05000321/LER-2026-003, Automatic Reactor Trip Due to High Reactor Pressure	Hatch	19 June 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Protection System	Cyber Security
05000414/LER-2026-001, B Steam Generator Tube Leak	Catawba	18 June 2026	10 CFR 50.73(a)(1), Submit an LER 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded	Steam Generator Reactor Coolant System Feedwater Main Turbine Main Steam	Safe Shutdown Eddy Current Testing Operational leakage Restart
05000412/LER-2026-001, Indications Identified During Reactor Vessel Head Inspection	Beaver Valley	11 June 2026	10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded	Reactor Coolant System Reactor Pressure Vessel	Large early release frequency Stress corrosion cracking
05000244/LER-2026-001, A Emergency Diesel Generator Invalid Actuation During Testing	Ginna	11 June 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Coolant System Emergency Diesel Generator	Safe Shutdown Invalid Actuation
05000259/LER-2026-002, Technical Specifications Required Shutdown Due to Reactor Water Cleanup System ASME Code Class 1 Leak	Browns Ferry	11 June 2026	10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown	Reactor Coolant System Reactor Water Cleanup	Safe Shutdown Pressure boundary leak Through-Wall Leak
05000443/LER-2026-001, Incorrect Steam Generator a Level Transmitters Resulted in Technical Specification Inoperability	Seabrook	10 June 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator
05000395/LER-2026-003, Main Steam Isolation Valve Failed to Close in Mode 3	Summer	28 May 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Reactor Coolant System Main Steam Isolation Valve Control Rod
05000325/LER-2026-002, Manual Reactor Protection System Actuation While Shutdown	Brunswick	28 May 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Protection System Control Rod
05000311/LER-2026-001, Refueling Water Storage Tank Volume Below the Minimum Requirement, a Condition That Could Have Prevented Fulfillment of a Safety Function	Salem	28 May 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Emergency Core Cooling System
05000278/LER-2026-001, Loss Load Center Due to Potential Transformer Failure	Peach Bottom	28 May 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function	Emergency Diesel Generator Primary Containment Isolation System Primary containment Emergency Core Cooling System	Unanalyzed Condition Invalid Actuation
05000395/LER-2026-002-01, Manual Reactor Trip for Steam Leak Near Feedwater Heater 1A	Summer	27 May 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Emergency Feedwater System	Flow Accelerated Corrosion Feedwater Heater
05000296/LER-2026-002, Technical Specification Prohibited Mode Change Due to Inoperable Reactor Core Isolation Cooling System	Browns Ferry	26 May 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Reactor Core Isolation Cooling	Overspeed
05000370/LER-2026-001, Reactor Coolant System Pressure Boundary Degraded Due to Through-Wall Flaw	Mcguire	26 May 2026		Steam Generator Reactor Coolant System	Boric Acid Non-Destructive Examination VT-2 Intergranular Stress Corrosion Cracking Liquid penetrant
05000461/LER-2026-002, Trip of Division 1 Diesel Generator Oil Room Exhaust Fan During Division 2 Diesel Generator Fire Protection Testing	Clinton	22 May 2026
05000334/LER-2025-001-02, Condition Prohibited by Technical Specifications and Event or Condition That Could Have Prevented Fulfillment of a Safety Function	Beaver Valley	21 May 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Unanalyzed Condition Time of Discovery Aging Management License Renewal Through-Wall Leak
05000260/LER-2026-001, High Pressure Coolant Injection Steam Line Isolation	Browns Ferry	20 May 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	High Pressure Coolant Injection
05000321/LER-2026-002, Licensed Nuclear Material Inventory Discrepancy	Hatch	20 May 2026
05000529/LER-2026-001, Manual Reactor Trip Due to Reactor Coolant Pump High Seal Temperature	Palo Verde	15 May 2026
05000454/LER-2026-002, Loss of Automatic Function Identified on Both Trains of Control Room Ventilation Temperature Control	Byron	15 May 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Reactor Coolant System	Past operability
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