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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 57141 | 23 May 2024 16:46:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram Due to Turbine Trip Signal | The following information was provided by the licensee via email: At 2223 CDT on May 23, 2024, with Quad Cities Unit 2 at 38 percent power, the reactor automatically tripped due to a turbine trip signal resulting in main stop valve closure, creating a valid reactor protection system signal. Reactor vessel level reached the low-level set-point following the scram, resulting in valid Group II and Group III containment actuation signals. The trip was not complex with all systems responding as expected post-trip. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group II and Group III isolation. Operations responded using their emergency operating procedures and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 remains at 100 percent power. There was no impact on 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: Unit 2 was at a reduced power for maintenance. | Reactor Protection System Main Condenser | |
| ENS 56676 | 11 August 2023 08:29:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram | The following information was provided by the licensee via phone and email: At 0329 (CDT) on August 11, 2023, with Unit 2 in Mode 1 at 90 percent power, the reactor automatically tripped due to a turbine trip. The trip was uncomplicated with all systems responding normally post-trip. The cause and details of the event are under investigation. Containment isolation valves actuated closed in multiple systems on a valid Group II signal. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B), and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group II isolation. Operations responded using the emergency operating procedure and stabilized the plant in Mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Reactor Protection System Main Condenser | |
| ENS 56210 | 4 November 2022 19:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Scram Due to Rising Water Level | The following information was provided by the licensee via email: On November 4, 2022, at 1400 hours, with Unit 2 (U2) in Mode 1 at 100 percent power, a manual scram was inserted on U2 due to rising reactor water level, which occurred following an unexpected opening of the 2B Feedwater Regulating Valve. Following the reactor scram, reactor water level decreased to approximately 0 inches, which resulted in an automatic Group II and Group III isolation (expected response). Reactor Water Level control has been established in a normal band. The cause and details of the event are under investigation. The Unit 2 scram was not complicated. Operations responded using the Emergency Operating Procedures and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 was unaffected by the event and remains at 100 percent power. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Feedwater Reactor Protection System Main Condenser | |
| ENS 55975 | 4 July 2022 06:04:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Reactor Manual Scram Due to Lowering Reactor Water Level | The following information was received from the licensee via facsimile: On July 4, 2022 at 0104 CDT, with Unit 2 in Mode 1 at 100 percent power, a manual scram was inserted on U2 due to lowering reactor water level, which occurred following an unexpected closure of the 2A Feedwater Regulating Valve. Following the reactor scram, reactor water level decreased to approximately minus 16 inches, which resulted in an automatic Group II and Group III isolation (expected response). Following the scram, reactor water level rose to plus 75 inches resulting in a trip of all three Reactor Feedwater Pumps. At 0114 CDT, Reactor Water Level lowered to less than the Feedwater Pump High Level Trip setpoint and the 2C Reactor Feedwater Pump was restarted. Reactor Water Level control has been established in a normal band. The cause and details of the event are under investigation. The Unit 2 scram was not complicated. Operations responded using the Emergency Operating Procedure and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 was unaffected by the event and remains at 100 percent power. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). There was no impact on 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 licensee will notify the Illinois Emergency Management Agency. | Feedwater Reactor Protection System Main Condenser | |
| ENS 54239 | 25 August 2019 16:02:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram Due to Main Generator Ground Fault Relay | On August 25, 2019, at 1102 (CDT), Quad Cities Unit 1 experienced an automatic scram from 100 percent power. All rods fully inserted and there were no complications. The trip was initiated from a main generator ground fault relay. Troubleshooting of the fault is in progress. All systems responded as designed. There were no systems inoperable and no TS (Technical Specification) action statements were in progress prior to the Reactor Scram. Reactor water level dropped below the Group 2 and Group 3 Reactor Water Level Isolation set-points as expected, and recovered via the Feedwater system. Standby Gas Treatment System auto started and Reactor Building Ventilation Isolation occurred as expected. Unit 1 remains in Mode 3. Decay heat is being removed using the steam bypass valves to the condenser and the safety relief valves did not lift as a result of the trip. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). The NRC Resident Inspector has been notified. Unit 2 was not affected. | Feedwater Reactor Building Ventilation Standby Gas Treatment System Safety Relief Valve | |
| ENS 53626 | 26 September 2018 05:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram Due to Generator Output Breaker Trip | On September 26, 2018 at 1908 CDT. an automatic scram was received on U1 following main generator 345 kV output breaker 7-8 trip with 345 kV output breaker 6-7 already opened for maintenance on line 0401. Following the reactor scram, reactor water level decreased to approximately minus 15 inches, which resulted in automatic Group II and Group Ill isolations (expected response). Reactor pressure rose to approximately 1083 psig, and the 3B and 3C low set relief valves opened briefly to control reactor pressure. Reactor water level and reactor pressure have been restored to their normal bands. All systems responded properly to the event. Unit 1 remains in Mode 3, with reactor pressure being controlled on the turbine bypass valves. The cause and details of the event are under investigation. Unit 2 was unaffected by the event and remains at 100% power. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A)." All control rods inserted. Decay heat is being removed via the main condenser. The licensee notified the NRC Resident Inspector. | Main Condenser Control Rod | |
| ENS 50949 | 3 April 2015 02:33:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to Steam Leak | On April 2, 2015 at 2133 CDT, a manual scram was inserted on Unit 1 following discovery of a steam leak in the Turbine Building at the D-ring, near the Turbine Bypass valves. Following the reactor scram, reactor water level decreased to approximately -2 inches, which resulted in an automatic Group II and Group III isolation (expected response). The steam leak was isolated by manual closure of the Main Steam Isolation Valves. All systems responded properly to the event. Unit 1 remains in Mode 3, with cooldown in progress. Reactor water level is in the normal level band. The cause and details of the event are under investigation. Unit 2 was unaffected by the event and remains at 100 percent power. Operators reduced reactor power to 20 percent before initiating a SCRAM. All rods fully inserted and the reactor is shutdown and stable. The electrical supply is in a normal shutdown lineup. The reactor is being supplied by normal feedwater, and decay heat is being controlled by use of the ADS valves. The licensee is currently cooling down and depressurizing the reactor in preparation for repair of the steam leak. The licensee has notified the NRC Resident Inspector and the State of Illinois Resident Inspector. | Feedwater Main Steam Isolation Valve | 05000254/LER-2015-005 |
| ENS 49988 | 2 April 2014 18:40:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Alert Declared Due to Fire in Unit 2 Turbine Building | Quad Cities Unit 2 Alert Classification (HA3) Due to Fire. On April 2, 2014, at 1340 CDT, an ALERT was declared due to a fire in the Unit 2 turbine building. Prior to declaring the ALERT, Unit 2 was manually scrammed at 1302 CDT. All control rods inserted and all automatic isolations actuated as designed. The Main Steam Isolation Valves were manually closed. The fire has been extinguished. Unit 2 is currently in Hot Shutdown. The cause of the event is under investigation. Unit 1 remains at 100% power. The Senior Resident Inspector has been notified of the event. Unit 2 is still being supplied from off-site power and is in a normal shutdown electrical lineup with the exception of Bus 29-1 (480 VAC safety bus) that was deenergized. One Unit 2 emergency diesel generator is inoperable due to the loss of power to its cooling water pump. The licensee has notified the State and local agencies. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA OPS Center, EPA EOC, FDA EOC, and Nuclear SSA via email.
At 2132 CDT on April 2, 2014, the licensee terminated the Unit 2 Alert declaration. Unit 2 is stable in Mode 3 (Hot Shutdown). Unit 2 is proceeding to Mode 4 (Cold Shutdown) on shutdown cooling. The licensee notified the NRC Resident Inspector and the State emergency agencies. Notified the IRD (Gott), R3DO (Passehl), and NRR EO (McGinty). Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA OPS Center, EPA EOC, FDA EOC, and Nuclear SSA via email. | Emergency Diesel Generator Main Steam Isolation Valve Shutdown Cooling Control Rod | 05000265/LER-2014-002 |
| ENS 47847 | 18 April 2012 20:11:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unit Two Automatic Reactor Scram on High Reactor Pressure | On April 18, 2012, at 1511 hours (CDT), an automatic scram occurred on high reactor pressure. The pressure increase occurred during post-modification testing on the main generator automatic voltage regulator, which had been upgraded during the recent refueling outage. Following the reactor scram, reactor water level decreased to approximately zero inches, which resulted in automatic Group II and III isolations (Reactor Water Clean Up and Secondary Containment Isolation) as expected. All systems responded properly to the event. The cause of the event is still under investigation. Unit 1 was unaffected by the event and remains at 100% power. This report is being made in accordance with 10CFR50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). All Control Rods fully inserted, decay heat is being removed through the bypass steam valves to the main condenser, and the plant remains in a normal shutdown electrical alignment. The high reactor pressure appears to have been caused by a load rejection associated with the main generator voltage regulator testing. The licensee has informed the NRC Resident Inspector. | Secondary containment Main Condenser Control Rod | |
| ENS 46951 | 13 June 2011 10:10:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to Steam Leak in Turbine Building | On June 13, 2011 at 0510 CDT, a manual scram was inserted on Unit 1 following discovery of a steam leak in the turbine building downstream of the Main Turbine Stop Valves. Following the reactor scram, reactor water level decreased to approximately -19 inches, which resulted in automatic Group II and Group III isolations (expected response). The steam leak was isolated by closure of the Main Turbine Stop Valves. All systems responded properly to the event. Unit 1 remains in Mode 3 (hot shutdown), maintaining reactor pressure with the Main Turbine Bypass Valves; reactor water level is in the normal level band. The cause of the event is still under investigation. Unit 2 was unaffected by the event and remains at 100% power. This report is being made in accordance with 10CFR50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). The licensee has notified the NRC Resident Inspector. | Main Turbine | |
| ENS 46184 | 17 August 2010 19:14:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Initiated Due to Recirculation Pump Trip | On August 17, 2010, at 1414 hours, a manual scram was inserted on Unit 2 due to rising reactor water level. The water level increase was caused by a trip of the 2B Recirculation Pump. Restoration of the 2B Recirculation Pump Programmable Logic Controller (PLC) on the 2B Adjustable Speed Drive (ASD) was in progress at the time of the event. Following the reactor scram, reactor water level decreased to approximately minus 15 inches, which resulted in automatic Group II and III isolations as expected. All systems responded properly to the event. The cause of the event is still under investigation. Unit I was unaffected by the event and remains at 100% power. This report is being made in accordance with 10CFR50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). All control rods inserted on the scram. No ECCS initiations occurred. No safety or relief valves lifted. The unit is stable in Mode 3 at 926 psig and 530 degrees Fahrenheit. Pressure is being controlled on the turbine bypass system. The licensee notified the NRC Resident Inspector and the Illinois Department of Nuclear Safety. | Control Rod | |
| ENS 46169 | 12 August 2010 08:58:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unit 1 Reactor Automatic Scram Due to Turbine Trip | While performing a main condenser flow reversal at 0358 (CDT) on August 12, 2010 the Unit 1 reactor received an automatic scram on turbine stop valve closure. Turbine stop valve closure was initiated from a turbine trip on low vacuum. Reactor water level decreased to approximately -3 (inches), which resulted in automatic Group II and III isolations as expected. All systems responded properly to the event. Unit One remains in Mode 3, maintaining reactor pressure with reactor water level in the normal level band. The cause of the event is still under investigation. Unit 2 was unaffected by the event and remains at 100% power. This report is being made in accordance with 10CFR50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). All rods fully inserted. Normal feedwater is supplying the reactor with decay heat removal via the turbine bypass valves. No safety relief valves lifted during the transient. The transient was initiated during the condenser flow reversal when one of the flow reversal valves failed to fully reverse the flow. This resulted in inadequate heat transfer to circ water at full power operation causing the condenser vacuum to increase. In addition, the condenser vacuum trip of the turbine appears to have initiated before it was actually required. Overall, the scram was characterized as uncomplicated and all systems functioned as required. | Feedwater Decay Heat Removal Safety Relief Valve Main Condenser | |
| ENS 43198 | 28 February 2007 07:20:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unit 2 Reactor Manually Scrammed Due to Decreasing Condenser Vacuum | At 0120 hours on February 28, 2007 the Unit 2 Reactor was manually scrammed due to decreasing condenser vacuum. All control rods fully inserted during the scram. Reactor water level decreased to approximately -10", which resulted in automatic Group II and III isolations as expected. All systems responded properly to the event. Unit 2 remains in Mode 3, maintaining reactor pressure, with reactor water level in the normal level band. The cause of this event is still under investigation. Unit 1 was unaffected by the event and remains at 97% power. This report is being made in accordance with 10CFR50.72 (b)(2)(iv)(B) and 10CFR50.72 (b)(3)(iv)(A). The Main Condenser remains in service removing decay heat via the bypass valves. All ECCS equipment is available, if needed. The licensee will inform the State and has informed the NRC Resident Inspector. | Main Condenser Control Rod | |
| ENS 42356 | 22 February 2006 07:22:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram Due to Valid Main Turbine Load Reject Signal | At 0122 hours (CST) on February 22, 2006, the Unit 1 reactor automatically scrammed from 85% power due to a valid turbine-generator load reject signal. The maximum reactor pressure was approximately 1050 PSIG during the event. All control rods inserted to their full-in position. Reactor water level decreased to approximately -10 inches, which resulted in automatic Group 2 and 3 isolations as expected. All systems responded properly to the event. Unit 1 is in Mode 3, maintaining reactor pressure, and reactor water level in the normal level band. An investigation into the Unit 1 scram and load reject is in progress. Unit 2 remains at 85% power. This report is being made in accordance with 10CFR 50.72(b)(2)(iv)(B) and 10 CFR50.72(b)(3)(iv)(A). No SRVs opened during the transient. Post shutdown electrical lineup is normal with the exception of the loss of one offsite power supply. Decay heat is being removed via the turbine bypass valves to the main condenser and feedwater being provided via main feedwater. Unit 2 is in a Tech Spec LCO for Loss of One Offsite power source. The licensee notified the NRC Resident Inspector. | Feedwater Main Turbine Main Condenser Control Rod | |
| ENS 41782 | 17 June 2005 16:20:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram Due to Ehc Malfunction | At 1120 hours (CDT) on June 17, 2005, the Unit 1 reactor automatically scrammed from 85% power due to a valid high reactor pressure signal. The maximum reactor pressure was approximately 1044 psig during the event. All control rods inserted to their full-in position. Initial indications are that the reactor pressure increase was caused by a malfunction in the Electro-Hydraulic Control (EHC) system, which resulted in closure of the main turbine control valves. The main turbine bypass valves (nine) opened as expected in response to the pressure increase. No reactor pressure vessel safety or relief valves were required to actuate during the event. Reactor water level decreased to approximately -20 inches, which resulted in automatic Group 2 and 3 isolations as expected. All systems responded properly to the event. Unit 1 is in Mode 3 with a cooldown in progress and reactor water level in the normal level band. An investigation into the Unit 1 scram is in progress. Unit 2 remains at 94% power. This report is being made in accordance with 10CFR 50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector. | Reactor Pressure Vessel Control Rod | |
| ENS 40625 | 30 March 2004 13:40:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Scram During Turbine Thrust Bearing Wear Detector Testing | At 0740 hours (CST) during testing of the turbine thrust bearing wear detector, a main turbine trip occurred. This resulted in an automatic reactor scram due to turbine stop valve closure. Following the scram all Group II (Primary Containment) and Group III (Reactor Water Cleanup) isolations occurred as expected. All essential equipment functioned as required. Unit 2 remains in Mode 3 with reactor water level in the normal level band. An investigation into the Unit 2 turbine trip is in progress. Unit 1 was unaffected by the event and remains at 85% power. All control rods fully inserted. Decay heat is being removed via steam to the main condenser using the bypass valves. The Licensee notified the NRC Resident inspector. | Primary containment Reactor Water Cleanup Main Condenser Control Rod |