Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56804 | 19 October 2023 16:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Seismic Monitoring Capability | The following information was provided by the licensee via phone and email: Reporting due to loss of emergency preparedness capabilities. Seismic monitoring capability is non-functional due to loss of power. These monitors do not have a credited compensatory measure. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The NRC Resident Inspector has been notified. The licensee intends to notify state and local officials. | ||
| ENS 54803 | 29 July 2020 00:49:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Failed Radiation Detector | Radiation monitor RE-69, 'Guardhouse Area Radiation Detector' was found failed on operator rounds. RE-69 is a category A1 piece of equipment that provides the sole means of indication for a parameter used to directly assess emergency action level (EAL) RA3.1, 'dose rate greater than 15 mR/hr in either of the following areas: Control Room (R-1), Central Alarm Station (R-69).' A compensatory measure was subsequently established and the ability to assess EAL RA3.1 has been restored. There was no impact on the health and safety of the public or plant personnel. The NRC Senior Resident Inspector has been notified. | ||
| ENS 53700 | 28 October 2018 05:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitoring Panel System Inoperable | This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) for a major loss of emergency assessment capability at the Prairie Island Nuclear Generating Plant. At 1435 CDT on October 28, 2018, troubleshooting of the Seismic Monitoring Panel resulting from the receipt of Control Room annunciator 47023-0603 (Seismic Monitor Panel) determined that the '(Operational Basis Earthquake) OBE Exceedance' alarm on the Seismic Monitoring Panel will not alarm and determined the panel is non-functional. The Seismic Monitoring Panel system functions to provide indication that the OBE threshold has been exceeded following a seismic event and is used in the Prairie Island Nuclear Generating Plant Emergency Plan to perform classification of Initiating Condition 'Seismic event greater than OBE levels' and Emergency Action Level HU2.1. Station personnel are monitoring the seismic recorders for event alarms on a 15 minute frequency due to alarm function failure. The station is developing repair plans for restoration of the alarm function. This event does not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | ||
| ENS 53286 | 23 March 2018 21:35:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Assessment Capability | This report is made for a loss of Emergency Assessment Capability associated with Emergency Action Levels for Toxic and Flammable Gas and is reportable under 10 CFR 50.72 (b)(3)(xiii). During an emergency equipment inventory it was identified that methods were not available to detect levels of toxic or flammable gas at the IDLH (Immediately Dangerous to Life and Health) level for a number of substances. The IDLH is used to assess the Alert Emergency Action Level. The ability of the Control Room Staff to detect and respond to the presence of toxic or flammable gas is unaffected. Because there have been no chemical spills or releases that would require sampling to be performed, the health and safety of the public was not affected. The NRC Resident Inspector has been notified. The State of Minnesota will be notified. | ||
| ENS 51528 | 11 November 2015 14:26:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Shield Building Vent Gas Radiation Monitor Out of Service for Planned Maintenance | At 0826 CST on 11/11/2015, 1R-22, Shield Building Vent Gas Radiation Monitor, was removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications - when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 1R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building Ventilation Stack is also monitored by high range monitor, 1R-50, which is used for the same purpose in Site Area or General Emergency classifications. 1R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-22 prior to its removal from service. The duration of this maintenance is scheduled for 24 hours and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector.
The licensee indicated that the duration of maintenance was extended for approximately 24 hours to allow continued repair of the monitor. The NRC Resident Inspector was notified. Notified the R3DO (Kozak). | Shield Building | |
| ENS 51266 | 27 July 2015 14:02:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Planned Outage for Plant Computer Systems | On July 27, 2015 at 0902 (CDT), (the site commenced) a planned outage of the Emergency Response Data System (ERDS) and Safety Parameter Display System (SPDS), referred to as 'plant computer'. The unavailability of ERDS and SPDS could significantly affect the site's ability to respond to an emergency if one were to occur. During this time, Operations will be utilizing the site's procedures 1C1.5 and 2C1.5, 'OPERATION WITHOUT COMPUTER', which requires additional operators for monitoring of equipment affected by the loss of the plant computer. Additionally, as this is a planned outage, the work week schedule has been modified to ensure limited interactions required by Operations during this time frame. The site expects ERDS and SPDS to be operational 1200 July 28, 2015. This event is reportable under 10 CFR 50.72(b)(3)(xiii), Any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of Control Room indication, Emergency Notification System (ENS), or Offsite Notification System). The ENS and Offsite Notification System are not affected by this planned outage. The health and safety of the public are not impacted by this planned outage. The NRC Resident Inspector has been informed. | Emergency Response Data System Safety Parameter Display System | |
| ENS 51013 | 25 April 2015 02:25:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Assessment Capability Due to Out-Of-Service Radiation Monitors | At 2125 on 4/24/15, 1R-2, Containment Vessel Area Radiation Detector failed. Previously, 1R-7, Incore Seal Table Area Radiation Detector, had failed on 4/20/15. The compensatory measure for 1R-2 out-of-service is to verify 1R-7 operating properly and the compensatory measure for 1R-7 out-of-service is to verify 1R-2 operating properly. With both monitors out-of-service and Unit 1 operating in Mode 5, no compensatory measure is available that will allow timely classification of two Emergency Action Levels (EALs) - Notification of Unusual Event (NUE) classification (RU2.2) and Alert classification (RA3.2). This results in a Loss of Emergency Assessment Capability while 1R-2 and 1R-7 are concurrently out-of-service. This is a reportable condition per 10 CFR 50.72(b)(3)(xiii). Monitoring of radiological conditions in Unit 1 Containment showed no indication of RCS leakage or elevated radiation levels prior to the failure of 1R-2. Unit 1 Containment also remains monitored by 1R-48, Containment Hi Range Area Radiation Detector A and 1R-49, Containment Hi Range Area Radiation Detector B, which currently indicate normal radiation levels. Unit 1 Shield Building Stack is also monitored by 1R-50, Shield Building High Range Vent Gas Radiation Detector, which also currently indicates normal radiation levels. Additionally, a temporary portable radiation monitor has been placed near the location of 1R-2 and is being continuously monitored. The plant remains in a safe condition and there was no effect to the health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50948 | 2 April 2015 17:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitor Not Available for Emergency Plan Assessment | Northern States Power Company - Minnesota (NSPM) has completed a review of seismic monitor performance at the Prairie Island Nuclear Generating Plant (PINGP) over the past 3 years. The emergency preparedness plan requires seismic monitoring instruments to diagnose an earthquake for emergency action levels (EAL) HA1.1 (Seismic Event Greater Than Operating Basis Earthquake (OBE) as indicated by 'OBE Exceedance' alarm on Seismic Monitoring Panel) or HU1.1 (Earthquake felt in plant as indicated by Valid 'Event' alarm on Seismic Monitoring Panel). Contrary to that requirement, this review identified 6 unplanned instances where the seismic monitor was non-functional that were not previously reported, and 3 planned instances where the seismic monitor was non-functional for greater than 24 hours that were not previously reported. Since there was no compensatory measure that could be credited when the seismic monitor was non-functional, an emergency classification at the ALERT or UNUSUAL EVENT level could not be obtained with site instrumentation for a seismic event. The seismic monitor is currently functional, however it was determined to be non-functional on the following dates: Unplanned out of service: 1. August 14, 2012 2. November 16, 2012 3. November 18 2012 4. November 21, 2012 5. December 5, 2012 6. January 16, 2013 Planned greater than 24 hour out of service: 1. December 14, 2012 2. September 3, 2014 3. September 30, 2014 The unplanned non-functional conditions of the seismic monitor have been corrected and were entered into the NSPM Corrective Action Program. The loss of assessment capability is reportable to the NRC within 8 hours of discovery in accordance with 10 CFR 50.72(b)(3)(xiii). This report is required per 10 CFR 50.72(a)(1)(ii) as an event that occurred within 3 years of the date of discovery. Corrective actions are in progress to address the missed reporting of seismic monitor unavailability. The licensee notified the NRC Resident Inspector. | ||
| ENS 50672 | 12 December 2014 08:48:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Auxiliary Building Normal Ventilation Radiation Monitor Failed | At 0248 CST on December 12, 2014, 2R-30, Auxiliary Building Normal Vent Radiation Monitor, failed. This monitor was the redundant monitor for 2R-37, Auxiliary Building Normal Vent Radiation Monitor, which was previously taken out of service for planned maintenance. With 2R-30 and 2R-37 out of service, there are no monitors that will allow for timely classification of two Emergency Action Levels (EALS) - NUE (Notification of Unusual Event) and Alert Classifications. This results in a loss of emergency assessment capability while 2R-30 and 2R-37 are out of service. This is a reportable condition in accordance with 10CFR50.72(b)(3)(xiii). The Auxiliary Building ventilation effluent monitor readings were normal and there were no elevated readings in Auxiliary Building area monitors prior to the unavailability of these monitors. The health and safety of the public was not affected by this issue. The activity to repair and return one of the monitors to service is continuous until restored. The licensee has notified the NRC Resident Inspector. | ||
| ENS 50652 | 3 December 2014 15:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Control Room Area Radiation Monitor Failed Low | At 0950 CST on December 3, 2014, R-1 Control Room Area Radiation Monitor failed low and was taken out of service. This monitor has no redundant monitor that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications - when out of service. This results in a Loss of Emergency Assessment Capability while R-1 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Control Room readings were normal as evidenced on R-1 prior to its failure. Compensatory measures have been established with a Portable Area Monitor installed in the Control Room adjacent to R-1. Corrective maintenance is in progress and will continue until the monitor is returned to service. The health and safety of the public was not affected by this issue. The licensee has notified the NRC Resident Inspector. | ||
| ENS 50487 | 24 September 2014 12:28:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Shield Building Vent Gas Radiation Monitor Out of Service for Planned Maintenance | At 0728 CDT on 9/24/2014, 2R-22 Shield Building Vent Gas Radiation Monitor was removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications - when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 2R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 2 Shield Building Ventilation Stack is also monitored by high range monitor, 2R-50, which is used for the same purpose in Site Area or General Emergency classifications. 2R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 2R-22 prior to its removal from service. The duration of this maintenance is scheduled for 1 hour and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50446 | 11 September 2014 15:09:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Shield Building Vent Gas Radiation Monitor Out of Service for Planned Maintenance | At 1009 CDT on September 11, 2014, 1R-22 Shield Building Vent Gas Radiation Monitor was removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 1R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building Ventilation Stack is also monitored by high range monitor, 1R-50, which is used for the same purpose in Site Area or General Emergency classifications. 1R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-22 prior to its removal from service. The duration of this maintenance is scheduled for 8 hours and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50424 | 4 September 2014 13:43:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | 1R-50 Shield Building High Range Vent Gas Radiation Monitor Out of Service for Planned Maintenance | At 0843 CDT on September 4th, 2014, 1R-50 High Range Shield Building Vent Gas Monitor was removed from service for planned maintenance. This monitor provides indication of release of gaseous radioactivity to the environment. There is not a compensatory measure that will allow timely classification of two Emergency Action Levels when out of service: General Emergency Event RG1.1 and Site Area Emergency Event RS1.1. This results in a loss of emergency assessment Capability while 1R-50 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building ventilation stack is also monitored by radiation monitor 1R-22 that is used for the same purpose in Alert or Unusual Event Emergency classifications. 1R-22 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-50 prior to its removal from service. The maintenance is scheduled for ten hours or will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50266 | 10 July 2014 13:38:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | High Range Shield Building Vent Stack Gas Monitor Removed from Service for Maintenance | At 0830 CDT on July 10, 2014, 2R-50 High Range Shield Building Vent Stack Gas Monitor was removed from service for planned maintenance. 2R-50 was planned for an out of service time of approximately 8 hours. The clearance order associated with the work isolated the flow path to the sample pump. Subsequent to the execution of the clearance order, it was discovered that the flow path to the alternate sample pump was also unavailable inhibiting the ability to implement compensatory measures. With 2R-50 rad monitor sample pump out of service and no alternate sampling available, timely classification of two Emergency Action Levels (EALs), SAE (Notification of Site Area Emergency) and General Emergency classifications would not be achievable. This results in a Loss of Emergency Assessment Capability while 2R-50 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 2 Shield Building Ventilation Stack is also monitored by the Shield Building Vent Gas Monitor, 2R-22, which is used for the same purpose in NUE (Notification of Unusual Event) and Alert classifications. 2R-22 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 2R-22 prior to removing 2R-50 from service. This planned maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50051 | 23 April 2014 15:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | 2R-22 Shield Building Vent Gas Radiation Monitor Removed from Service for Planned Maintenance | At 1000 CDT on April 23, 2014, 2R-22, Shield Building Vent Gas Radiation Monitor was removed from service for planned maintenance. This monitor has no compensatory measures that will allow timely classification of two Emergency Action Levels (EALs); NUE (Notification of Unusual Event) and Alert classifications when out of service. It is also used for offsite dose projection calculations. This results in a loss of emergency assessment capability while 2R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). The Unit 2 Shield Building Ventilation Stack is also monitored by the high range monitor, 2R-50, which is used for the same purpose in Site Area Emergency classifications. 2R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidence by normal reading on 2R-22 prior to its removal from service. Maintenance is expected to last approximately 4 hours and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of the radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 50001 | 4 April 2014 19:53:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitor Declared Non-Functional Due to Spurious Alarm | At 1453 CDT on April 04, 2014, the station's Seismic Monitor generated a seismic event alarm that was determined to be invalid based upon no recorded readings above alarm setpoint, no seismic activity being felt on site, and no activity detected by National Earthquake Information Center or Monticello Nuclear Generating Plant. The monitor was declared non-functional since it would not generate a control board seismic event alarm during an actual event until the invalid event was reset. This monitor has no credited compensatory measure that will allow timely classification of two Emergency Action Levels (EALs), NUE (Notification of Unusual Event) and Alert classifications when out of service. This results in a Loss of Emergency Assessment Capability while the Seismic Monitor is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Maintenance has reset the alarm and has evaluated the monitor's performance. The alarm has been determined to be spurious. The monitor is working properly and will generate a control board alarm during an actual event, as determined by observed normal operation and the lack of any self-diagnostic error messages. At 1900 CDT on April 04, 2014 the monitor was declared functional and returned to service. There was no seismic activity during the out of service period indicated by the local seismic monitor display and no reports of seismic activity were reported to the site by National Earthquake Information Center or Monticello Nuclear Generating Plant. This event did not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | ||
| ENS 49943 | 21 March 2014 18:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Shield Building Vent Gas Rad Monitors Out of Service for Planned Maintenance | At 1330 CDT on March 21, 2014, 1R-22 and 2R-22, Shield Building Vent Gas Radiation Monitors will be removed from service for planned preventative maintenance and therefore (will be) nonfunctional. These monitors have no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs); NUE (Notification of Unusual Event) and Alert classifications when out of service. They are also used for offsite dose projection calculations. This will result in a Loss of Emergency Assessment Capability while 1R-22 and 2R-22 are out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 and Unit 2 Shield Building Ventilation Stacks are also monitored by high range monitors, 1R-50 and 2R-50, which are used for the same purpose in Site Area or General Emergency classifications. 1R-50 and 2R-50 are being monitored and are indicating normal values. There are no radioactive leaks that will impact the Shield Buildings as evidenced by normal readings on 1(2)R-22 prior to their removal from service. Preventative maintenance (belt inspections) is expected to last approximately 1 hour. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 49824 | 12 February 2014 17:13:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Circulating Water Discharge Monitor Out of Service | At 1113 CST on February 12, 2014, R-21 Circulating Water Discharge Monitor failed during routine surveillance testing and was declared nonfunctional. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications - when out of service. This results in a Loss of Emergency Assessment Capability while R-21 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). There are no radioactive leaks that will impact the Circulating Water System as evidenced by normal readings on R-21 prior to its failure. In addition all other liquid effluent radiation monitors that monitor releases to the Circulating Water Discharge are in-service and have normal readings. Corrective maintenance is in progress and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Circulating Water System | |
| ENS 49806 | 7 February 2014 12:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Shield Building Vent Gas Radiation Monitor Failure | At 0620 CST on February 7, 2014, 1R-22 Shield Building Vent Gas Radiation Monitor failed and was declared nonfunctional. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs); NUE (Notification of Unusual Event) and Alert classifications when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 1R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building Ventilation Stack is also monitored by high range monitor, 1R-50, which is used for the same purpose in Site Area or General Emergency classifications. 1R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-22 prior to its failure. Corrective maintenance is in progress and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 49799 | 6 February 2014 13:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Radiation Monitor Out of Service for Maintenance | At approximately 0730 CST on February 6, 2014, 1R-22 Shield Building Vent Gas Radiation Monitor will be removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs), NUE (Notification of Unusual Event) and Alert classifications when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 1R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building Ventilation Stack is also monitored by high range monitor, 1R-50, which is used for the same purpose in Site Area or General Emergency classifications. 1R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-22 prior to removing it from service. This planned maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 49745 | 20 January 2014 08:16:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Shield Building Gaseous Radiation Monitor | 2R-22, Unit 2 Shield Building Ventilation Gaseous Radiation Monitor was removed from service at 0216 CST on 01/20/2014 due to a broken belt. 2R-22 is important to the site's emergency plan for Notification of Unusual Event and Alert classifications in the event of an unplanned gaseous release from the Unit 2 Shield Building stack. It is also used for offsite dose projection calculations. There is no backup instrumentation or compensatory measure to perform these functions while 2R-22 is out of service. This results in a loss of emergency assessment capability, thus is reportable per 10CFR 50.72(b)(3)(xiii). 2R-22 readings were normal prior to the equipment failure. Unit 2 Shield Building Ventilation Stack is also monitored by high range monitor, 2R-50, which is used for the same purpose in Site Area or General Emergency classifications. 2R-50 is being monitored and is indicating normal values. This event did not result in the unplanned release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. Immediate efforts are underway to repair 2R-22. The licensee has notified the NRC Resident Inspector. | Shield Building | |
| ENS 49507 | 6 November 2013 06:58:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | R-21 Circulating Water Discharge Radiation Monitor Planned Outage | When transferring power supplies to a non-safety related cooling tower bus for planned outage maintenance, R-21, the Circulating Water Discharge Radiation Monitor was removed from service at 0058 (CST) and returned to service at 0111 (CST). There is no installed backup for R-21 which has an emergency response function to provide indication of gaseous liquid effluent release to the environment. This monitor has no compensatory measure that will allow timely classification of two NUE (Notification of Unusual Event) and Alert classifications when out of service. This resulted in a loss of emergency assessment capability while R-21 was out of service. There are no radioactive leaks that impact the Circulating Water System. The licensee notified the NRC Resident Inspector. * * * RETRACTION AT 1155 EST ON 12/2/13 FROM WAYNE EPPEN TO DANIEL MILLS * * * Based on further reviews of plant drawings and discussion with the Radiation Monitor System Engineer, R-21 was not inoperable when power supplies were transferred to the non-safety related Cooling Tower Bus. While R-21 was logged out of service during the transfer on November 6, 2013, it did not lose power and was not out of service. R-21 did not lose the ability to provide continuous monitoring of discharge canal effluent or monitoring in the event of an unplanned radiological release. Our defense in depth strategies are relied upon to take actions to protect the health and safety of the public. The licensee has notified the NRC Resident Inspector. Notified the R3DO (Duncan). | Circulating Water System | |
| ENS 49259 | 9 August 2013 15:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Radiation Monitor Out of Service | During the performance of SP (Surveillance Procedure) 1027.2A, NMC Radiation Monitor Train A Calibration, Radiation Monitor R-21, Circulating Water Discharge Radiation Detector failed the source test point three times and was removed from service. R-21 has an emergency response function to provide indication of gaseous or liquid effluent release to the environment. This monitor has no compensatory measure that will allow timely classification of two NUE (Notification of Unusual Event) and Alert classifications when out of service. This is a priority 1 activity to repair the monitor. The repair activity is continuous and is in progress. There are not radioactive leaks that impact the Circulating Water System. The NRC Resident Inspector was notified. | Circulating Water System | |
| ENS 48620 | 21 December 2012 13:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Response Data System (Erds) | At approximately 0730 CST, Xcel Energy Prairie Island Nuclear Generating Plant was informed of a loss of internet and data services due to equipment problems with the Wide Area Network (WAN). The loss of data services resulted in the loss of ERDS communication capabilities with the NRC. The WAN and ERDS were restored at 0921 CST. The licensee has notified the NRC Resident Inspector. | Emergency Response Data System | |
| ENS 44828 | 4 February 2009 19:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Sirens Out of Service Due to Planned Maintenance | The Prairie Island Nuclear Generating Plant is making an ENS notification in accordance with 10 CFR 50.72(b)(3)(xiii) due to planned maintenance on the Goodhue County radio repeaters. This maintenance will result in unavailability of 51 of the 117 sirens in the 10-mile Emergency Planning Zone (EPZ) for approximately 3 hours. The maintenance is scheduled to occur on the afternoon of 02/04/2009. The Goodhue County Sheriff's Office has been notified to implement the established process of back-up route alerting if required. Upon completion of the maintenance a cancel test will be performed to verify availability of the Goodhue County sirens and an update to this notification will be provided. The NRC Resident Inspector has been notified.
The cancel test was performed by the Goodhue County Sheriff's Office to all Goodhue County sirens successfully. All sirens have been returned to service. The licensee will be notifying the NRC Resident Inspector. Notified R3DO (Ring). | ||
| ENS 44175 | 29 April 2008 12:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Tsc Ventillation During Scheduled Maintenance | This notification is to report a Loss of Emergency Preparedness Capability in accordance with 10 CFR 50.72(b)(3)(xiii). At 0750 CDT on 4/29/08, the Technical Support Center (TSC) Ventilation System was removed from service for a scheduled surveillance procedure (SP 1738) to replace charcoal filters and measure the cleanup efficiency. It is scheduled to be returned to service on 5/1/08 (at approximately 1500 CST). The TCS ventilation system is now considered non-functional. The TSC will be staffed in the event it is needed and radiological conditions monitored. If radiological conditions require actions, procedure F3-6, 'Activation and operation of the TSC,' Section 7.6 directs the TSC management to relocate TSC activities to a radiological safe area if necessary. Alternate facilities are available. The Licensee notified the NRC Resident Inspector. | ||
| ENS 44157 | 23 April 2008 09:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Tsc Ventilation System Considered Non-Functional | At 0410 CDT on 4/23/08 the Technical Support Center (TSC) Ventilation System was removed from service for scheduled maintenance on the Technical Support Center (TSC) cleanup fan. Without adequate flow rates through the TSC cleanup filter, the TSC ventilation system is considered non-functional. Due to the extent of planned work, prompt restoration of the ventilation system will not be available. Contingency plans are in place to utilize the TSC as long as radiological conditions allow. Procedure F3-6, 'Activation and Operation of the TSC', Section 7.6, directs TSC management to relocate TSC activities to a radiological safe area if necessary. The TSC Ventilation system expected return to service is 1200 CDT 4/23/2008. The licensee notified the NRC Resident Inspector.
The TSC ventilation system will remain out of service until approximately Friday, April 25, at 1500 CDT. This is due to unforeseen degradation of the ventilation fan motor. The licensee will be notifying the NRC Resident Inspector. Notified R3DO (Jamnes Cameron) | ||
| ENS 44071 | 17 March 2008 13:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Degraded Habitability Control | At approximately 0800 CDT on 3/17/08, operations personnel identified and investigated an issue with excessive noise/vibration of the Technical Support Center (TSC) cleanup fan. Investigation revealed that the TSC cleanup fan exhaust damper set screws, which attach the positioner to the damper shaft, had become loose and were slipping on the damper shaft. With this damper not adequately attached to the positioner the damper cannot be controlled and therefore flow through the cleanup filter cannot be controlled. Without adequate flow rates through the TSC cleanup filter, the TSC ventilation system is considered non-functional. As of 1400 CDT, repair and testing of the damper has been completed and the TSC ventilation is now functional. Had an emergency condition occurred during the time the repairs took place, contingency plans were in place to utilize the TSC as long as radiological conditions allowed. Procedure F3-6, 'Activation and Operation of the TSC,' Section 7.6, directs TSC management to relocate TSC activities to a radiological safe area if necessary. The licensee notified the NRC Resident Inspector. | ||
| ENS 44057 | 12 March 2008 19:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Long Term Habitability of Technical Support Center Under Accident Dose Analysis Exceeds Acceptance Criteria | At approximately 1430 CDT on 3/12/08 Prairie Island staff completed a preliminary review of a revised dose analysis for the Prairie Island Technical Support Center (TSC) that called into question the long term habitability of the TSC under bounding accident conditions. The preliminary calculation result exceeds the 30-day 5 rem whole body dose acceptance criteria of NUREG-0696 and is based on bounding case assumptions consistent with Regulatory Guide 1.4 (including fuel melt, highest allowable containment leakage and bounding atmospheric dispersion factors). The primary contributor is an approximately 25 square foot window in the north wall of the TSC. Compensatory measures are being established to provide shielding over the window in the TSC. The licensee will notify the NRC Resident Inspector. | ||
| ENS 43515 | 24 July 2007 07:56:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Ventilation Inoperable | During performance of the Technical Support Center (TSC) Ventilation System Operability Test, an outside air damper failed to close causing a failure of the TSC Ventilation System to attain the required 0.125 inches water column positive pressure. If an emergency condition occurs during the time the repairs are being made, plans are to utilize the TSC as long as radiological conditions allow. Procedure F3-6 ACTIVATION AND OPERATION OF THE TSC, section 7.6, directs TSC management to relocate TSC activities to a radiological safe area if necessary. The licensee notified the NRC Resident Inspector.
Technical Support Center (TSC) Ventilation System is now operable. R3DO (Steve Orth) notified. The NRC Resident Inspector was notified of this event update by the licensee. | ||
| ENS 42250 | 11 January 2006 13:43:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Modification to the Unit 2 Process Computer That Will Impact Erds and Spds | The Unit 2 Plant Process Computer System (PPCS) will be taken out of service for an approximate 2 week period to implement a planned modification. The current PPCS is being replaced and the computer outage is required to allow cutover to the new PPCS. During this time period ERDS and SPDS will not be available. Unit 2 ERDS and SPDS parameters will be monitored by control board indications. Compensatory actions have been developed. This is an 8-hour reportable event per 10 CFR50.72(b)(3)(xiii) Major Loss of Assessment Capability. The operation of plant systems will not be affected due to this planned action. The Unit 2 PPCS outage started at 0743 CST on 1/11/2006. The licensee has informed the NRC Resident Inspectors of the modification and schedule. The NRC was previously notified of this planned outage via letter dated November 7, 2005.
The Unit 2 Plant Process Computer System (PPCS) was restored at 1801 CST on 01/18/06. The Unit 2 Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) have also been returned to service. The licensee notified the NRC Resident Inspector. Notified R3DO (M Phillips) | Emergency Response Data System Safety Parameter Display System | |
| ENS 42188 | 5 December 2005 15:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Plant Process Computer System (Ppcs) Will Be Taken Out of Service for Approximatley 2 Weeks. | The Plant Process Computer (PPCS) will be taken out of service for an approximately 2 week period to implement a planned modification. The current PPCS is being replaced and the computer outage is required to allow cutover to the new PPCS. During this time period ERDS and SPDS will not be available. ERDS and SPDS parameters will be monitored by control board indications. Compensatory actions have been developed. This is an 8-hour reportable event per 10 CFR50.72(b)(3)(xiii) Major Loss of Assessment Capability. The operation of plant systems will not be affected due to this planned action. The PPCS outage is expected to commence around 0600 CST on 12/5/05. The licensee has informed the NRC Resident Inspectors of the modification and schedule. The NRC was previously notified of this planned outage via letter dated November 7, 2005. The NRC Resident Inspector was notified of this event by the licensee.
The Plant Process Computer System was restored at 2330 CST on 12/15/05. The Safety Parameter Display System (SPDS) has been returned to service. The Emergency Response Data System (ERDS) portion of the system will be turned over once the testing has been completed. The licensee will notify the NRC Resident Inspector. Notified R3DO (Burgess).
This notification is an update to previously made notification, EN# 42188. As of 14:30 CST on 1/6/06 the Unit 1 Emergency Response Data System (ERDS) has been accepted for use and is considered fully operational. The licensee notified the NRC Resident Inspector. Notified the R3DO (Ring) | Emergency Response Data System Safety Parameter Display System |