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
05000395/LER-2025-003-02, Condition Prohibited by Technical Specifications	Summer	29 April 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator Feedwater Auxiliary Feedwater Emergency Feedwater System	Overspeed trip
05000395/LER-2025-005-01, (Vcsns), Condition Prohibited by Technical Specifications	Summer	29 April 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator Feedwater Emergency Feedwater System	Enforcement Discretion Overspeed trip Overspeed
05000325/LER-2026-001, Primary Containment Penetration Local Leak Rate Testing Failure	Brunswick	29 April 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded	High Pressure Coolant Injection Reactor Core Isolation Cooling Primary containment	Local Leak Rate Testing
05000259/LER-2025-002-01, Unit 1/2 480V Load Shed Logic Division 1/11 Inoperable Longer than Allowed by Technical Specifications	Browns Ferry	28 April 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Safe Shutdown Mission time Past operability Loss of Offsite Power
05000321/LER-2026-001, Manual Reactor Trip Due to Reaching Subcriticality	Hatch	24 April 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Feedwater Reactor Protection System Control Rod
05000296/LER-2026-001, Main Steam Isolation Valve Inoperable Due to Poppet Valve Scale Buildup	Browns Ferry	22 April 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Main Steam Isolation Valve Primary containment Main Steam Line
05000333/LER-2026-002, Containment Isolation Valve Actuations Caused by Spurious Undervoltage Relay Trip in Reactor Protection System Electric Power Monitoring	FitzPatrick	21 April 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Protection System Primary Containment Isolation System Primary containment Reactor Building Ventilation Reactor Water Cleanup Standby Gas Treatment System Main Steam Line	Half scram Undervoltage Relay
05000313/LER-2026-001, Emergency Diesel Generator Inoperability Due to Open Circuit in Engineered Safeguards Starting Circuit	Arkansas Nuclear	20 April 2026	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)(i)(B), Prohibited by Technical Specifications	Emergency Diesel Generator	Safe Shutdown Past operability FLEX
05000446/LER-2026-001, Unit, Condition Prohibited by Technical Specifications for Containment Ventilation and Isolation Due to Human Performance Error	Comanche Peak	20 April 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Emergency Diesel Generator	Operability Assessment
05000333/LER-2026-001, Reactor Core Isolation Cooling (RCIC) Inadvertent Actuation	FitzPatrick	16 April 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Feedwater High Pressure Coolant Injection Reactor Core Isolation Cooling Residual Heat Removal	Reactor Vessel Water Level
05000416/LER-2026-002, Loss of Secondary Containment Due to Failed Seals	Grand Gulf	14 April 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Secondary containment Primary containment
05000397/LER-2026-001, Manual Reactor Scram Due to Loss of Both Reactor Recirculation Pumps	Columbia	9 April 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown	Reactor Protection System Reactor Recirculation Pump Emergency Core Cooling System
05000499/LER-2025-002-01, Supplement to Automatic Reactor Trip Due to Main Transformer Lockout	South Texas	6 April 2026		Steam Generator Emergency Diesel Generator Main Transformer	Loss of Offsite Power
05000298/LER-2026-001, Diesel Generator 1 Maintenance Exceeded 7-Day Limiting Condition for Operation	Cooper	6 April 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Safe Shutdown Enforcement Discretion Abnormal operational transient Loctite
05000458/LER-2026-001, Loss of Division III Electrical Bus Due to Breaker Trip	River Bend	6 April 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)(x) 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)(A) 10 CFR 50.73(a)(2)(viii)(B)	Service water Emergency Diesel Generator High Pressure Core Spray	Ultimate heat sink Loss of Offsite Power
05000416/LER-2026-001, High Pressure Core Spray Inoperable Due to Breaker Trip	Grand Gulf	2 April 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)(x) 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)(A) 10 CFR 50.73(a)(2)(viii)(B)	Service water Reactor Core Isolation Cooling High Pressure Core Spray Emergency Core Cooling System
05000395/LER-2026-002, (Vcsns), Manual Reactor Trip for Steam Leak Near Feedwater Heater 1A	Summer	31 March 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Emergency Feedwater System	Flow Accelerated Corrosion Feedwater Heater
05000282/LER-2026-001, Diesel Driven Cooling Water Pump Auto Start Based on How System Pressure Due to Broken Valve Reach-Rod Bolt	Prairie Island	30 March 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Service water
05000373/LER-2025-001-01, Automatic Scram on Turbine Control Valves Fast Closure on Generator Lockout	LaSalle	27 March 2026		Reactor Protection System Emergency Core Cooling System Control Rod
05000269/LER-2026-001, Switchyard Vital Battery Specific Gravity Surveillance Error Results in Operation or Condition Prohibited by Technical Specifications	Oconee	26 March 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Feedwater Service water	FLEX Large early release frequency
05000395/LER-2026-001, (Vcsns), Operations Prohibited by Technical Specifications (TS)	Summer	20 March 2026	10 CFR 50.73(a)(1), Submit an LER 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Feedwater
05000334/LER-2025-001-01, Condition Prohibited by Technical Specifications and Event or Condition That Could Have Prevented Fulfillment of a Safety Function	Beaver Valley	19 March 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 Past operability Aging Management Large early release frequency License Renewal Through-Wall Leak
05000259/LER-2026-001, Plant, Unit 1, Safety System Functional Failure Due to High Pressure Coolant Injection Drain Valves Inoperable	Browns Ferry	19 March 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	High Pressure Coolant Injection
05000482/LER-2025-002-01, Generation Station, Loss of Both Trains of Control Room Air Conditioning Causes Condition That Could Have Prevented Fulfillment of a Safety Function	Wolf Creek	16 March 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Control Room Emergency Ventilation
05000316/LER-2026-001, Automatic Reactor Trip Due to 21 Steam Generator Low Water Level with Steam Flow-Feed Flow Mismatch	Cook	12 March 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater Decay Heat Removal Control Rod
05000530/LER-2025-002, Violation of Technical Specification Limiting Condition of Operation 3.6.3	Palo Verde	5 March 2026			Time of Discovery
05000348/LER-2026-001, Three Pressurizer Safety Valves Lift Pressure Outside of Technical Specifications Limits Due to Setpoint Drift	Farley	3 March 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i)(8)		Time of Discovery
05000461/LER-2025-002-01, Automatic Scram on High Reactor Water Level	Clinton	3 March 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Feedwater Reactor Protection System Reactor Pressure Vessel	Safe Shutdown
05000259/LER-2025-002, Unit 1/2 480V Load Shed Logic Division I/Ii Inoperable Longer than Allowed by Technical Specifications	Browns Ferry	17 February 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Mission time Past operability Loss of Offsite Power
05000530/LER-2025-001, Unintentional Uncontrolled Vital Area Keys	Palo Verde	13 February 2026
05000254/LER-2025-005-01, For Quad Cities Nuclear Power Station, Unit 1, Scram Due to 125 Vdc Voltage Fluctuations from Battery Cell Failure	Quad Cities	6 February 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Feedwater Reactor Protection System Emergency Diesel Generator Main Steam Isolation Valve Reactor Core Isolation Cooling Primary containment Main Turbine Core Spray Reactor Building Ventilation Automatic Depressurization System Emergency Core Cooling System Main Condenser	Reactor Vessel Water Level Past operability Intergranular Stress Corrosion Cracking
05000296/LER-2025-002-01, Reactor Core Isolation Cooling Inoperable Due to a Failed Ramp Generating Signal Converter	Browns Ferry	2 February 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	High Pressure Coolant Injection Reactor Core Isolation Cooling
05000395/LER-2025-003-01, V.C Summer Nuclear Station, Unit 1, Condition Prohibited by Technical Specifications	Summer	29 January 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator Feedwater Auxiliary Feedwater Emergency Feedwater System	Overspeed trip
05000259/LER-2025-001-01, Reactor Scram Due to Low Reactor Water Level	Browns Ferry	29 January 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Feedwater High Pressure Coolant Injection Reactor Protection System Primary Containment Isolation System Reactor Recirculation Pump
05000499/LER-2025-001-01, Inoperable Essential Cooling Water Strainer Could Have Prevented Fulfillment of a Safety Function and Resulted in Condition Prohibited by Technical Specifications	South Texas	29 January 2026	10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications		Past operability
05000528/LER-2025-004-01, Train a Emergency Diesel Generator Emergency Stop with System Actuation Supplement	Palo Verde	27 January 2026		Emergency Diesel Generator
05000318/LER-2025-002-01, Condition Prohibited by Technical Specifications Due to Condition 3.7.12.A Required Restoration Time Exceeded	Calvert Cliffs	22 January 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator Service water Main Turbine	High Energy Line Break
05000499/LER-2025-002, Automatic Reactor Trip Due to Main Transformer Lockout	South Texas	20 January 2026		Steam Generator Emergency Diesel Generator Main Transformer	Loss of Offsite Power
05000237/LER-2025-003, High Pressure Coolant Injection Inoperable Due to Failed Indicating Light and Blown Fuse	Dresden	15 January 2026	10 CFR 50.73(a)(2)(v), Loss of Safety Function	High Pressure Coolant Injection Core Spray Automatic Depressurization System Low Pressure Coolant Injection
05000461/LER-2025-004, Emergency Diesel Generator Automatic Start Due to Emergency Reserve Auxiliary Transformer Trip	Clinton	13 January 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Emergency Diesel Generator
05000270/LER-2026-001, Loss of AC Power to Unit 2 Main Feeder Buses After Opening Potential Transformer Drawer Resulting in Actuation of Keowee Hydroelectric Units	Oconee	13 January 2026	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Service water
05000395/LER-2025-005, V. C. Summer Nuclear Station, Unit 1, Condition Prohibited by Technical Specifications	Summer	12 January 2026	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Steam Generator Feedwater Emergency Feedwater System	Enforcement Discretion Overspeed trip Overspeed
05000373/LER-2025-001, Automatic Scram on Turbine Control Valves Fast Closure on Generator Lockout	LaSalle	31 December 2025	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Protection System Emergency Core Cooling System Control Rod	Temporary Modification
05000400/LER-2025-002, Incorrect Current Value Used During Power Range Nuclear Instrument Calibration	Harris	29 December 2025	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications	Feedwater
05000445/LER-2025-002, Pressure Transmitter Inoperable for a Duration Prohibited by TS	Comanche Peak	29 December 2025		Reactor Coolant System	Time of Discovery Anticipated operational occurrence Past operability
05000237/LER-2025-002, Valid Reactor Protection System Actuation While Shutdown	Dresden	26 December 2025	10 CFR 50.73(a)(2)(iv)(A), System Actuation	Reactor Protection System Control Rod	Scram Discharge Volume
05000382/LER-2025-004, Station Air Leak in Control Room Envelope Results in a Condition That Could Have Prevented Fulfilment of a Safety Function	Waterford	23 December 2025	10 CFR 50.73(a)(2)(v), Loss of Safety Function	Control Room Envelope	Stress corrosion cracking
05000334/LER-2025-001, Condition Prohibited by Technical Specifications and Event or Condition That Could Have Prevented Fulfillment of a Safety Function	Beaver Valley	23 December 2025	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 Past operability Large early release frequency Through-Wall Leak
05000321/LER-2025-002, Reactor Protection System Instrumentation for Turbine Control Valve Fast Closure Inoperable	Hatch	19 December 2025	10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 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)	Reactor Protection System Electrohydraulic Control	Past operability
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