| | Site | Start date | Title |
|---|
| 05000461/LER-2025-001, MSIV B21-F022D Limit Switch Failed Testing | Clinton | 12 November 2025 | MSIV B21-F022D Limit Switch Failed Testing |
| 05000461/LER-2023-002-01, Reactor Core Isolation Cooling Inoperable Prior to Mode Change | Clinton | 24 September 2024 | Reactor Core Isolation Cooling Inoperable Prior to Mode Change |
| 05000461/LER-2023-002, Reactor Core Isolation Cooling System Inoperable Prior to Mode Change | Clinton | 16 February 2024 | Reactor Core Isolation Cooling System Inoperable Prior to Mode Change |
| 05000454/LER-2023-001-01, A Control Room Ventilation Inoperable Due to Jumpers Left on 0PR031J and 0PR32J | Byron | 12 October 2023 | A Control Room Ventilation Inoperable Due to Jumpers Left on 0PR031J and 0PR32J |
| 05000461/LER-2023-001, Grid Fault Results in Switchyard Breaker Trips and Reactor Scram | Clinton | 31 March 2023 | Grid Fault Results in Switchyard Breaker Trips and Reactor Scram |
| 05000461/LER-2021-002-02, Core Alterations with Source Range Monitor Inoperable Results in Condition Prohibited by Technical Specifications | Clinton | 1 November 2022 | Core Alterations with Source Range Monitor Inoperable Results in Condition Prohibited by Technical Specifications |
| 05000461/LER-2021-002-01, Core Alterations with Source Range Monitor Inoperable Results in Condition Prohibited by Technical Specifications | Clinton | 24 February 2022 | Core Alterations with Source Range Monitor Inoperable Results in Condition Prohibited by Technical Specifications |
| 05000461/LER-2021-001, Core Monitoring System Software Modeling Error Results in Condition Prohibited by Technical Specifications | Clinton | 19 August 2021 | Core Monitoring System Software Modeling Error Results in Condition Prohibited by Technical Specifications |
| 05000461/LER-2020-003, Reactor Core Isolation Cooling System Card Fuse Failure Results in a Condition Prohibited by Technical Specifications and That Could Have Prevented Fulfillment of a Safetv Function Needed to Control | Clinton | 22 February 2021 | Reactor Core Isolation Cooling System Card Fuse Failure Results in a Condition Prohibited by Technical Specifications and That Could Have Prevented Fulfillment of a Safetv Function Needed to Control. |
| 05000456/LER-2020-001, Train a Auxiliary Feedwater Pump Was Inoperable Due to a Failed Suction Pressure Lead/Lag Card | Braidwood | 25 November 2020 | Train a Auxiliary Feedwater Pump Was Inoperable Due to a Failed Suction Pressure Lead/Lag Card |
| 05000461/LER-2020-001, Submittal of LER 2020-001-00 for Clinton Power Station, Unit 1, Reportable Contraband Event | Clinton | 23 March 2020 | Submittal of LER 2020-001-00 for Clinton Power Station, Unit 1, Reportable Contraband Event |
| 05000461/LER-2019-004-01, Safety Relief Valve Wiring Issue Results in Condition Prohibited by Technical Specifications | Clinton | 29 January 2020 | Safety Relief Valve Wiring Issue Results in Condition Prohibited by Technical Specifications |
| 05000461/LER-2019-004, Safety Relief Valve Wiring Issue Results in Condition Prohibited by Technical Specifications | Clinton | 29 November 2019 | Safety Relief Valve Wiring Issue Results in Condition Prohibited by Technical Specifications |
| 05000461/LER-2019-002, For Clinton Power Station, Unit 1, Turbine Driven Reactor Feed Pump Hydraulic Control Failure Results in Automatic Scram | Clinton | 1 October 2019 | For Clinton Power Station, Unit 1, Turbine Driven Reactor Feed Pump Hydraulic Control Failure Results in Automatic Scram |
| 05000461/LER-2019-001, Main Feed Breaker Failed to Close During Bus Shift | Clinton | 19 July 2019 | Main Feed Breaker Failed to Close During Bus Shift |
| 05000461/LER-2018-005-02, Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux | Clinton | 24 April 2019 | Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux |
| 05000461/LER-2018-005-01, Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux | Clinton | 5 March 2019 | Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux |
| 05000254/LER-2018-004-01, Reactor Scram Due to Turbine-Generator Load Reject | Quad Cities | 28 February 2019 | Reactor Scram Due to Turbine-Generator Load Reject |
| 05000461/LER-2018-003-01, Load Driver Card Failure Resulting in High Pressure Core Spray Inoperability | Clinton | 5 February 2019 | Load Driver Card Failure Resulting in High Pressure Core Spray Inoperability |
| 05000461/LER-2018-005, Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux | Clinton | 21 December 2018 | Unplanned Reactor Scram During Maintenance Outage Due to High Intermediate Range Monitor Flux |
| 05000457/LER-2018-001, Reactor Coolant System Pressure Boundary Leak on a Steam Generator Bowl Drain Line Due to High Cycle Fatigue Cracking Initiated from Small Welding Defects | Braidwood | 6 December 2018 | Reactor Coolant System Pressure Boundary Leak on a Steam Generator Bowl Drain Line Due to High Cycle Fatigue Cracking Initiated from Small Welding Defects |
| 05000461/LER-2018-004, Undervoltage Condition Caused by an Offsite Ameren Transformer Bushing Failure Initiates an Automatic Start of an Emergency Diesel Generator | Clinton | 21 November 2018 | Undervoltage Condition Caused by an Offsite Ameren Transformer Bushing Failure Initiates an Automatic Start of an Emergency Diesel Generator |
| 05000461/LER-2018-003, Load Driver Card Failure Resulting in High Pressure Core Spray Lnoperability | Clinton | 17 August 2018 | Load Driver Card Failure Resulting in High Pressure Core Spray Lnoperability |
| 05000456/LER-2018-006, Manual Unit Trip on Low Steam Generator Level Following Trip of a Turbine Feedwater Pump Due to a Design Issue | Braidwood | 2 August 2018 | Manual Unit Trip on Low Steam Generator Level Following Trip of a Turbine Feedwater Pump Due to a Design Issue |
| 05000461/LER-2018-002, Division 2 Diesel Generator Inoperability Due to Air Receiver Remaining Isolated Following Clearance Removal Resulting in Unplanned Shutdown Risk Change | Clinton | 16 July 2018 | Division 2 Diesel Generator Inoperability Due to Air Receiver Remaining Isolated Following Clearance Removal Resulting in Unplanned Shutdown Risk Change |
| 05000456/LER-2018-005, Unit Trip on Turbine Anti-Motoring Circuit Caused by Weld Blockage of Instrument Line with a Failed Differential Pressure Switch Assembly | Braidwood | 28 June 2018 | Unit Trip on Turbine Anti-Motoring Circuit Caused by Weld Blockage of Instrument Line with a Failed Differential Pressure Switch Assembly |
| 05000456/LER-2018-004, A Emergency Diesel Generator Output Breaker Opened During a Surveillance Which Resulted in Unplanned Actuations of Bus 141 Undervoltage Relay | Braidwood | 21 June 2018 | A Emergency Diesel Generator Output Breaker Opened During a Surveillance Which Resulted in Unplanned Actuations of Bus 141 Undervoltage Relay |
| 05000456/LER-2018-001, A Emergency Diesel Generator Lost Voltage During a Surveillance Due to a Failed Exciter Diode, Which Resulted in an Unplanned Actuation of Bus 141 Undervoltage Relay | Braidwood | 18 June 2018 | A Emergency Diesel Generator Lost Voltage During a Surveillance Due to a Failed Exciter Diode, Which Resulted in an Unplanned Actuation of Bus 141 Undervoltage Relay |
| 05000456/LER-2018-002, B Emergency Diesel Generator Tripped on Overspeed During Testing Due to Broken Close-Assist Springs on the Turbocharger Inlet Butterfly Valve While the 1A Emergency Diesel Generator Was Inoperable | Braidwood | 18 June 2018 | B Emergency Diesel Generator Tripped on Overspeed During Testing Due to Broken Close-Assist Springs on the Turbocharger Inlet Butterfly Valve While the 1A Emergency Diesel Generator Was Inoperable |
| 05000456/LER-2018-003, Indications on Top Head to Upper Center Disc Weld of Reactor Head Identified Due to New Inspection Standards | Braidwood | 14 June 2018 | Indications on Top Head to Upper Center Disc Weld of Reactor Head Identified Due to New Inspection Standards |
| 05000461/LER-2018-001, Degraded Personnel Airlock Interlock Results in Loss of Primary Containment | Clinton | 29 May 2018 | Degraded Personnel Airlock Interlock Results in Loss of Primary Containment |
| 05000461/LER-1917-010, Regarding Division 1 Transformer Failure Leads to Instrument Air Isolation to Containment Requiring a Manual Reactor Scram | Clinton | 5 February 2018 | Regarding Division 1 Transformer Failure Leads to Instrument Air Isolation to Containment Requiring a Manual Reactor Scram |
| 05000461/LER-1917-009, Regarding Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 Kv Offsite Source | Clinton | 4 January 2018 | Regarding Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 Kv Offsite Source |
| 05000461/LER-1917-008, Re Division 3 Shutdown Service Water Pump Start Failure | Clinton | 11 August 2017 | Re Division 3 Shutdown Service Water Pump Start Failure |
| 05000461/LER-1917-007, Re Manual Reactor Scram Due to Loss of Feedwater Heating | Clinton | 9 August 2017 | Re Manual Reactor Scram Due to Loss of Feedwater Heating |
| 05000461/LER-1917-006, Re Secondary Containment Inoperable During Mode Change Due to Doors Propped Open | Clinton | 1 August 2017 | Re Secondary Containment Inoperable During Mode Change Due to Doors Propped Open |
| 05000461/LER-1917-005, Regarding Automatic Reactor Scram During the Performance of Scram Time Testing as a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip | Clinton | 27 July 2017 | Regarding Automatic Reactor Scram During the Performance of Scram Time Testing as a Result of an Invalid Oscillating Power Range Monitor Growth Rate Trip |
| 05000461/LER-1917-004, For Clinton Power Station, Unit 1 Main Steam Isolation Valve Local Leak Rate Test Limit Exceeded During Refueling Outage | Clinton | 10 July 2017 | For Clinton Power Station, Unit 1 Main Steam Isolation Valve Local Leak Rate Test Limit Exceeded During Refueling Outage |
| 05000461/LER-1917-003, Regarding Implementation of Enforcement Guidance Memorandum (Egm) 11-003, Revision 3 | Clinton | 3 July 2017 | Regarding Implementation of Enforcement Guidance Memorandum (Egm) 11-003, Revision 3 |
| 05000254/LER-1917-002, Regarding Four Main Steam Isolation Valves (Msivs) Closure Times Exceeded | Quad Cities | 26 May 2017 | Regarding Four Main Steam Isolation Valves (Msivs) Closure Times Exceeded |
| 05000461/LER-1917-002, Regarding Failure of the Division 1 Diesel Generator Ventilation Fan Load Sequence Relay Circuit During Concurrent Maintenance of RHR Division 2 Results in an Unanalyzed Condition | Clinton | 4 May 2017 | Regarding Failure of the Division 1 Diesel Generator Ventilation Fan Load Sequence Relay Circuit During Concurrent Maintenance of RHR Division 2 Results in an Unanalyzed Condition |
| 05000461/LER-2017-001, Regarding Failure of the 138 Kv Offsite Power Source Results in a Loss of Secondary Containment Vacuum | Clinton | 21 April 2017 | Regarding Failure of the 138 Kv Offsite Power Source Results in a Loss of Secondary Containment Vacuum |
| 05000461/LER-2016-010, Regarding Failure to Complete Technical Specification Required Actions within the Completion Time Resulted in a Condition Prohibited by Technical Specifications | Clinton | 13 December 2016 | Regarding Failure to Complete Technical Specification Required Actions within the Completion Time Resulted in a Condition Prohibited by Technical Specifications |
| 05000461/LER-2015-004-01, Regardomg Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 Kv Offsite Source | Clinton | 22 August 2016 | Regardomg Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 Kv Offsite Source |
| 05000461/LER-2016-009, Regarding Trip of Fuel Building Fans Due to Damper Failure Results in Loss of Secondary Containment | Clinton | 22 August 2016 | Regarding Trip of Fuel Building Fans Due to Damper Failure Results in Loss of Secondary Containment |
| 05000456/LER-2016-002, Regarding Inadequate Protection from Tornado Missiles Identified Due to Non-Conforming Design Conditions | Braidwood | 19 July 2016 | Regarding Inadequate Protection from Tornado Missiles Identified Due to Non-Conforming Design Conditions |
| 05000461/LER-2016-008, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 | Clinton | 15 July 2016 | Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 |
| 05000461/LER-2016-006, Missed Surveillance Results in a Condition Prohibited by Technical Specifications | Clinton | 10 June 2016 | Missed Surveillance Results in a Condition Prohibited by Technical Specifications |
| 05000461/LER-2016-005, Regarding Insulator Failure on the Reserve Auxiliary Transformer Results in a Loss of Secondary Containment Vacuum | Clinton | 31 May 2016 | Regarding Insulator Failure on the Reserve Auxiliary Transformer Results in a Loss of Secondary Containment Vacuum |
| 05000461/LER-2016-004, Regarding Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 Kv Offsite Source | Clinton | 26 May 2016 | Regarding Trip of Emergency Reserve Auxiliary Transformer Static Var Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 Kv Offsite Source |