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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 55976 | 4 July 2022 06:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Both Trains of Standby Gas Treatment Inoperable | The following information was received from the licensee via email: At 0130 CDT on July 4 2022, it was discovered both trains of Standby Gas Treatment System were simultaneously inoperable due to failure to reach required flow rates. Both trains were capable of starting but failed to reach the required flow of 4000 SCFM. Secondary Containment differential pressure was not able to be maintained at greater than or equal to 0.25 inches of vacuum water gauge, causing Secondary Containment to also be inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Secondary containment Standby Gas Treatment System | |
| ENS 53189 | 31 January 2018 19:10:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Momentary Loss of Secondary Containment | At 1310 hours (CST) on January 31, 2018, the Unit 2B fuel pool radiation monitor spiked high due to an invalid actuation which caused the U1 and U2 reactor building ventilation system to isolate, B train standby gas treatment system (SBGTS) started, and the control room ventilation system also isolated as designed. Secondary containment vacuum was lost for approximately one minute, and then subsequently returned to an acceptable level in accordance with Technical Specification 3.6.4.1, 'Secondary Containment.' As a result of this transient, secondary containment was inoperable for approximately one minute. No emergency conditions were determined to exist. Troubleshooting of the radiation monitor spike is underway. Given the temporary loss of secondary containment vacuum, this event is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. | Secondary containment Reactor Building Ventilation Standby Gas Treatment System | |
| ENS 52508 | 24 January 2017 16:00:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Interlock Doors Open Simultaneously | On January 24, 2017, at 1000 hours (CST), Operations was notified that two Secondary Containment interlock doors (between the Unit 2 Reactor Building and Unit 2 Turbine Building) were open simultaneously. The doors were immediately closed and Secondary Containment pressure remained negative. Unit 1 and Unit 2 share secondary containment. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open. As a result, entry into Technical Specification 3.6.4.1, Condition A. was made momentarily due to Secondary Containment being inoperable. This event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Senior Resident Inspector has been notified. The cause of this event was due to an equipment interlock (solenoid) failure and the doors are currently blocked closed. | Secondary containment | 05000254/LER-2017-001 |
| ENS 51659 | 16 January 2016 02:38:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Momentary Loss of Secondary Containment | On January 15, 2016 at 2038 CST, an alarm was received indicating Secondary Containment Differential Pressure rose unexpectedly above the Technical Specification Surveillance Requirement, SR 3.6.4.1.1, limit of 0.10 inch of vacuum water gauge. This loss of differential pressure occurred when Operations had entered the 2A Reactor Water Cleanup Pump room. The pump room door was closed and Secondary Containment Differential Pressure returned to Technical Specification limits in approximately 4 minutes. The Standby Gas Treatment System remained in standby and fully operable. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.1. As a result, entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to secondary containment being inoperable. Given the temporary loss of secondary containment, this event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Senior Resident Inspector has been notified." The licensee also notified the State of Illinois Emergency Management Agency. | Secondary containment Reactor Water Cleanup Standby Gas Treatment System | 05000254/LER-2016-002 |
| ENS 51650 | 12 January 2016 19:40:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Momentary Loss of Secondary Containment | On January 12, 2016, at 1340 CST, an alarm was received indicating secondary containment differential pressure rose unexpectedly above the Technical Specification Surveillance Requirement, SR 3.6.4.1.1, limit of 0.10 inch of vacuum water gauge. A reactor building supply fan was immediately secured to restore differential pressure below the Technical Specification limit. The secondary containment differential pressure returned to below the Technical Specification limit within one minute. The Standby Gas Treatment System remained in standby, and fully operable. At 1341 CST, the secured reactor building supply fan was restarted to restore the normal ventilation lineup. The secondary containment differential pressure remained below the Technical Specification limit. Troubleshooting is in progress. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.1. As a result, entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to secondary containment being inoperable. Given the temporary loss of secondary containment, this event is reportable under 50.72(b)(3)(v)(c) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Senior Resident Inspector has been notified. | Secondary containment Standby Gas Treatment System | 05000254/LER-2016-001 |
| ENS 51165 | 19 June 2015 06:53:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Interlock Doors Open Simultaneously | On June 19, 2015, at 0153 CDT, two Secondary Containment interlock doors (1/2 EDG (Emergency Diesel Generator) room door and the Unit 1 reactor building door) were open simultaneously. The doors were immediately closed and secondary containment pressure remained negative. This condition represents a failure to meet surveillance requirement 3.6.4.1.2 given two doors in a single access opening were open simultaneously. As a result entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to secondary containment being inoperable. This event is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. The door has been posted to notify to restrict access. The State of Illinois Emergency Management has been notified. | Secondary containment | 05000254/LER-2015-008 |
| ENS 51021 | 28 April 2015 14:35:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Two Secondary Containment Interlock Doors Open Simultaneously | On April 28, 2015, at 0935 CDT, the Shift Manager was notified that two Secondary Containment interlock doors (1/2 EDG room door and the Unit 1 reactor building door) were open simultaneously. The doors were immediately closed and secondary containment pressure remained negative. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open simultaneously. As a result entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to secondary containment being inoperable. This event is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. Personnel were posted in the area as a compensatory measure. The State of Illinois Emergency Management has been notified. | Secondary containment | 05000254/LER-2015-006 |
| ENS 50803 | 10 February 2015 16:55:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Interlock Doors Open Simultaneously | On February 10, 2015, at 1055 CST, the Shift Manager was notified that both (High Pressure Coolant Injection) HPCI Secondary Containment interlock doors were open simultaneously. The doors were immediately closed and secondary containment pressure remained negative. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open simultaneously. As a result entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to secondary containment being inoperable. This event is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. The licensee reported that personnel were posted in the area as a compensatory measure. The State of Illinois Emergency Management will be notified. | Secondary containment | 05000254/LER-2015-002 |
| ENS 50622 | 18 November 2014 15:00:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Interlock Doors Open Simultaneously | On November 18, 2014, at 0900 (CST), the Shift Manager was notified that two Secondary Containment interlock doors were open simultaneously. The doors were immediately closed and Secondary Containment pressure remained negative throughout the event. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open. As a result entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to Secondary Containment being inoperable. This event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. The State of Illinois has been notified. | Secondary containment | 05000254/LER-2014-004 |
| ENS 50132 | 23 May 2014 02:50:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Both Hpci Secondary Containment Airlock Doors Open Simultaneously | On May 22, 2014, at 2150 hours, the Shift Manager was notified that both HPCI Secondary Containment interlock doors were open simultaneously. The doors were immediately closed and Secondary Containment pressure remained negative. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open. As a result, entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to Secondary Containment being inoperable. This event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. | Secondary containment | 05000254/LER-2014-003 |
| ENS 49984 | 1 April 2014 18:57:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Unit 2 Secondary Containment Interlocked Doors Opened Simultaneously | On April 1, 2014, at 1357 hours, the Control Room was notified that two Secondary Containment interlock doors (between the Unit 2 Reactor Building and Unit 2 Turbine Building) were open simultaneously. The doors were immediately closed and Secondary Containment pressure remained negative. This condition represents a failure to meet Surveillance Requirement 3.6.4.1.2 given two doors in a single access opening were open simultaneously. As a result entry into Technical Specification 3.6.4.1, Condition A, was made momentarily due to Secondary Containment being inoperable. This event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Senior Resident Inspector has been notified. | Secondary containment | 05000254/LER-2014-002 |
| ENS 49870 | 5 March 2014 01:17:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Momentary Loss of Secondary Containment | At 1917 hours (CST) on March 4, 2014, the Unit 1B fuel pool radiation monitor spiked high due to an invalid actuation which caused the U1 and U2 reactor building ventilation system to isolate (the control room ventilation system also isolated as designed). The Standby Gas Treatment system was already in operation for a scheduled surveillance as of 1900 hours on March 4, 2014. During the ensuing pressure transient, the Reactor Building differential pressure momentarily went positive. As a result, Secondary Containment was declared inoperable. Given the temporary loss in secondary containment, this event is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector has been notified. After the transient, the reactor building ventilation system was shutdown for scheduled maintenance and the control room ventilation system was returned to its normal configuration. The Standby Gas Treatment system was operating to support planned reactor building ventilation system maintenance. Troubleshooting of the radiation monitor spike is underway. | Secondary containment Reactor Building Ventilation Standby Gas Treatment System | 05000254/LER-2014-001 |
| ENS 49727 | 15 January 2014 13:23:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Drywell Radiation Monitor Inoperable | At 0723 (CST) hours on January 15, 2014, the 2A Drywell Radiation Monitor was declared inoperable after exhibiting erratic performance. This monitor provides the input into one division of the primary containment isolation logic for a Group II isolation. As a result, the channel was placed in a tripped condition in accordance with Technical Specification 3.3.6.1, Condition B. Given both divisions are required to complete the Group II isolation logic, this condition is reportable in accordance with 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The 2A Drywell Radiation Monitor has been repaired and restored to an operable condition. The NRC Resident Inspector has been notified.
The purpose of this notification is to retract the ENS notification made on January 15, 2014 (ENS 49727). Upon further investigation it was verified that the Drywell Radiation Monitors do not mitigate the consequences of an accident as discussed in Chapters 6 and 15 of the Updated Final Safety Analysis Report and the Technical Specifications Bases for 3.3.6.1. Therefore, the threshold for reporting the issue as an event or condition that could have prevented the fulfillment of a safety function was not met (NUREG 1022 Revision 3 - Event Report Guidelines Section 3.2.7). The NRC Resident Inspector has been notified. Notified the R3DO (Orlikowski). | Primary containment | |
| ENS 48527 | 20 November 2012 19:21:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Drywell Radiation Monitor Inoperable | At 1321 (CST) hours on November 20, 2012, the 1B Drywell Radiation Monitor exhibited degraded performance at the conclusion of surveillance testing. This monitor provides the input into one division of the primary containment isolation logic for a Group II isolation. As a result, the channel was placed in a tripped condition in accordance with Technical Specification 3.3.6.1, Condition B. Given both divisions are required to complete the Group II isolation logic, this condition is reportable in accordance with 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The station is currently taking action to troubleshoot and restore the 1B Drywell Radiation Monitor to an operable condition. The NRC Resident Inspector has been notified.
ENS Retraction - Drywell Radiation Monitor Inoperable The purpose of this notification is to retract the ENS Report made on November 20, 2012, at 1827 EST hours (ENS Report # 48527). Further evaluation performed by Quad Cities Station confirms the 1B Drywell Radiation Monitor would have performed its safety function when required. Based on this subsequent evaluation, ENS Report # 48527 is being retracted. Note: On November 21, 2012, the 1B Drywell Radiation Monitor was successfully repaired and returned to Operable status. The licensee informed the NRC Resident Inspector. Notified R3DO (Bloomer). | Primary containment | |
| ENS 48332 | 21 September 2012 19:49:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Drywell Radiation Monitor Inoperable | At 1449 CDT on September 21, 2012, the 2B Drywell Radiation Monitor was found downscale during control room panel monitoring. This monitor provides the input into one division of the primary containment isolation logic for a Group II isolation. As a result, the channel was placed in a tripped condition at 1515 hours in accordance with Technical Specification 3.3.6.1, Condition B. Initial troubleshooting indicates that one of the two divisions of the isolation logic was inoperable. Given both divisions are required to complete the Group II isolation logic, this condition is reportable in accordance with 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The station is currently taking action to restore the 2B Drywell Radiation Monitor to an operable condition. The NRC Senior Resident Inspector has been notified. | Primary containment | |
| ENS 48282 | 6 September 2012 18:14:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Loss of Secondary Containment Ventilation for Eight Seconds | On September 6, 2012, at 1314 hours, the reactor building ventilation system was being restored to service following planned maintenance and surveillance activities. During the reactor building pressure transition when restoring reactor building ventilation (from the Standby Gas Treatment System), an employee entered a secondary containment interlock and identified a door leading to the environment had opened. The employee immediately secured the door and notified Operations personnel. A review of the door alarm history determined the door was open for approximately eight seconds. Given the temporary breech in secondary containment, this event is reportable under 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function. The licensee notified the NRC Resident Inspector. | Secondary containment Reactor Building Ventilation Standby Gas Treatment System |