Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56352 | 6 February 2023 11:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Communications and Assessment Capabilities | The following information was provided by the licensee via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of 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, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. | ||
| ENS 55325 | 24 June 2021 14:01:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Technical Support Center Capability | This is an eight-hour, non-emergency notification for a loss of Emergency Assessment Capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the Technical Support Center (TSC) supply fan belt had failed, which affects the functionality of an emergency response facility. Corrective maintenance activities will be performed to restore functionality. The work includes replacing the failed belt and restarting the TSC supply fan. The work duration is approximately 8 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature, radiological, or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff to an alternate location in accordance with applicable site procedures. (The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency.) There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector and Illinois Emergency Management Agency have been notified. | ||
| ENS 54090 | 26 May 2019 00:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Main Control Room Area Radiation Monitors | At 1930 (CDT) on 5/25/2019, communications were lost with the main control room area radiation monitors. These detectors are used to determine if an emergency action level (EAL) has been reached for initiating condition RA3 (Radiation levels that impede access to equipment necessary for normal plant operations, cooldown, or shutdown). This unplanned loss of the ability to evaluate an EAL for initiating condition RA3 is considered a loss of emergency classification capability and is reportable as a Major Loss of Emergency Preparedness Capabilities per 10 CFR 50.72(b)(3)(xiii). This is an 8-hour reportable notification. Portable area radiation monitors have been established as a compensatory measure per station procedures. The NRC Resident Inspector has been notified. | ||
| ENS 53180 | 23 January 2018 10:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Assessment Capability Due to Technical Support Center Planned Maintenance | At 0400 (CST) on 1/23/2018 the Braidwood Technical Support Center (TSC) HVAC (Heating, Ventilation and Air Conditioning) Emergency Makeup Air Filter train was taken out of service to perform a planned Makeup Air Filter charcoal replacement. The TSC HVAC Makeup Air Filter train will be rendered nonfunctional during the charcoal replacement. Subsequent charcoal and HEPA filter testing will restore functionality of the TSC HVAC Makeup Air Filter train. The expected duration of the charcoal replacement and subsequent testing is 30 hours. If an emergency is declared requiring TSC activation during the time TSC HVAC is non-functional, the TSC will be staffed and activated using existing emergency planning procedure unless the TSC becomes uninhabitable due to ambient temperature, radiological, or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff to an alternate location in accordance with applicable site procedures. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to a major loss of emergency preparedness capability. An update will be provided once the TSC HVAC Emergency Makeup Air Filter train functionality has been restored. The licensee has notified the NRC Resident Inspector.
On 1/26/18 at time 1539 EST, the TSC HVAC Emergency Makeup Air Filter train was returned to service following the planned Makeup Alr Filter charcoal replacement. Functionality was verified by charcoal and HEPA filter post maintenance testing. The licensee has notified the NRC Resident Inspector. Notified the R3DO (Cameron). | HVAC | |
| ENS 52103 | 18 July 2016 20:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Offsite Communications Capability | Loss of the Offsite Emergency Response Organization (ERO) notification system (Everbridge) identified the system cannot notify all ERO individuals. This constitutes a loss of offsite communications capability. The Offsite ERO notification system (Everbridge) capability loss of Braidwood was identified at approximately 1500 CDT on July 18, 2016, due to an undetermined loss of system communications, which is currently being investigated. The Offsite ERO notification system (Everbridge) capability loss for the common Emergency Response Facility (ERF) (Emergency Offsite Facility (EOF) at Cantera) was identified at approximately 1500 CDT on July 18, 2016. The issue has subsequently been reported resolved by the vendor at 1912 CDT and site testing has verified resolution at 2108 CDT. The onsite communication system was not affected. This event is reportable under 10 CFR 50.72(b)(3)(xiii) as a loss of communications capability. The NRC Resident Inspector has been notified. | ||
| ENS 51154 | 15 June 2015 12:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Tsc Ventilation to Be Removed from Service for Planned Maintenance | On 6/16/2015, planned preventive maintenance activities (will be) performed on the Braidwood Generating Station Technical Support Center (TSC), Ventilation System. The work will be completed within approximately 48 hours. This activity includes preventative maintenance that requires the TSC ventilation system to be out of service which will render the TSC ventilation system non-functional. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff as necessary. This event is reportable per 10 CFR 50.72(b)(3)(xiii) for 'any event that results in a major loss of emergency assessment capability.' The planned maintenance will not be able to restore the TSC condensing unit or ventilation system to service within the facility activation time specified in the emergency plan (1 hour) in the event of an accident. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. The licensee has notified the NRC Resident Inspector.
Braidwood Generating Station TSC ventilation was restored to available status at 0700 CDT on June 18, 2015. The previously reported system preventative maintenance has been completed. The licensee notified the NRC Resident Inspector. Notified the R3DO (Pelke). | ||
| ENS 51092 | 27 May 2015 14:45:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service for Planned Maintenance | On 5/27/15, planned preventive maintenance activities are being performed on the Braidwood Generating Station Technical Support Center (TSC), Ventilation System. The work will be completed within approximately 10 hours. This activity includes preventative maintenance that requires the TSC ventilation system to be out of service which will render the TSC ventilation system non-functional. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff as necessary. This event is reportable per 10CFR50.72(b)(3)(xiii) for 'any event that results in a major loss of emergency assessment capability.' The planned maintenance will not be able to restore the TSC condensing unit or ventilation system to service within the facility activation time specified in the emergency plan (1 hour) in the event of an accident. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. The licensee informed the NRC Resident Inspector.
Planned work is complete and the Technical Support Center was restored to service on May 27, 2015 at 1808 CDT. The licensee will notify the NRC Resident Inspector. Notified the R3DO (Lipa). | ||
| ENS 50957 | 6 April 2015 13:09:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service for Planned Maintenance | On 04/06/2015, planned preventive maintenance activities are being performed on the Braidwood Generating Station Technical Support Center (TSC) Ventilation System. The work will be completed within approximately 42 hours. This activity includes preventive maintenance on the TSC condensing unit which affects the TSC ventilation. During the planned maintenance, the TSC condensing unit will be rendered non-functional. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff as necessary. This planned maintenance will not impact the emergency filtration capability of the TSC. This event is reportable per 10CFR50.72(b)(3)(xiii) for 'any event that results in a major loss of emergency assessment capability.' The planned maintenance will not be able to restore the TSC condensing unit to service within the facility activation time specified in the emergency plan (1 hour) in the event of an accident. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. The licensee has notified the NRC Resident Inspector.
The TSC ventilation system has been restored to normal operation as of 0600 CDT on April 8, 2015. The NRC Resident Inspector has been notified. Notified R3DO (Skokowski). | ||
| ENS 50933 | 27 March 2015 14:41:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitor Not Available for Emergency Plan Assessment | Braidwood Generating Station has completed a review of seismic monitor performance. The emergency preparedness plan requires seismic monitoring instruments to diagnose an earthquake for emergency action levels (EAL) HA4 (natural and destructive phenomena affecting vital areas) or HU4 (natural and destructive phenomena affecting the protected area). Contrary to that requirement, this review identified 5 times in the past 3 years that the seismic monitor was non-functional such that emergency classification at the ALERT or UNUSUAL EVENT level could not be obtained with site instrumentation. The seismic monitor is currently functional; however, the seismic monitor was determined to be non-functional on the following dates: 1. April 24, 2012 2. December 5, 2012 3. December 20, 2012 4. June 17, 2013 5. October 8, 2014 These non-functional conditions of the seismic monitor have been corrected and were entered into the Braidwood Corrective Action Program. While Exelon procedural direction allowed the use of offsite sources to obtain seismic data when the seismic monitor is incapable of assessing emergency plan Emergency Action Levels (EALs), this was not explicitly referenced in the Braidwood approved EALs. 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. The licensee has notified the NRC Resident Inspector. | ||
| ENS 50431 | 6 September 2014 11:13:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Air Conditioning Condensing Units Out of Service | At 0613 (CDT) on 9/6/2014, Technical Support Center roof mounted condensing units were found tripped by operations personnel. An attempt was made to restart both condensing units, neither condensing unit would restart. This caused a loss of Technical Support Center cooling capability. Technical Support Center Air Handling system is in service and required filtration remains available. Wet bulb temperature of the TSC, taken at 0950 (CDT) is 78.0 degrees F. Corrective action process has been initiated. This event is reportable under 10 CFR 50.72(b)(3)(xiii) as described in NUREG-1022, Rev. 3, since this condition affects an emergency response facility. The NRC Resident Inspector has been notified. | ||
| ENS 50397 | 25 August 2014 10:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Planned Maintenance | On 8/25/2014, planned preventive maintenance activities are being performed on the Braidwood Generating Station Technical Support Center (TSC) Ventilation System. The work will be completed within approximately 42 hours. This activity includes preventive maintenance on the TSC condensing unit which affects the TSC ventilation. During the planned maintenance, the TSC condensing unit will be rendered non-functional. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff as necessary. This planned maintenance will not impact the emergency filtration capability of the TSC. This event is reportable per 10CFR50.72(b)(3)(xiii) for 'any event that results in a major loss of emergency assessment capability.' The planned maintenance will not be able to restore the TSC condensing unit to service within the facility activation time specified in the emergency plan (1 hour) in the event of an accident. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. The licensee has notified the NRC Resident Inspector.
Braidwood Generating Station TSC ventilation was restored to available status at 1200 CDT on August 29th, 2014. The previously reported system preventative maintenance has been completed. The licensee informed the NRC Resident Inspector. Notified R3DO (Stone). | ||
| ENS 50247 | 1 July 2014 12:15:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Offsite Alert and Notification System Failure | At approximately 0715 (CDT) on 7/1/2014, during the daily morning test, Braidwood Generating Station experienced Offsite Alert and Notification System (ANS) failure of sirens BD10 and BD13 due to a loss of power to the sirens. Loss of power to the sirens was due to the adverse weather conditions experienced on the evening of 6/30/2014. Siren BD10 provides coverage for 20% of Braidwood's Emergency Planning Zone (EPZ) population and siren BD13 provides coverage for 14.1% of the Braidwood EPZ population. This event is being reported in accordance with 10CFR50.72(b)(3)(viii) for '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, or offsite notification system).' The failure of the sirens resulted in the loss of the capability to alert a large segment of the population in the EPZ (~34%) for more than 1 hour. Per NEI 13-01, Rev 0, a large segment of the population in the EPZ should be taken to mean approximately 25% of the total EPZ population. Immediate actions taken included placing a portable generator online to restore siren BD10 at 1015 CDT on 7/1/2014. ComEd is currently in the area attempting to restore normal power. Proposed long term corrective actions including an upgrade to the sirens to contain a battery backup are being evaluated. The licensee has notified the NRC Resident Inspector. The county emergency managers (for Will County - (for siren) BD10 and Grundy County - (for siren) BD13) are aware of the siren outage and the requirements to initiate mobile route alerting (FEMA approved backup) if required.
Siren BD10 was restored to functional on 7/1/2014 at 1130 CDT. Siren BD13 was restored to functional on 7/2/2014 at 1145 CDT. The NRC Resident Inspector has been notified of this ENS update. Notified R3DO (McCraw) | ||
| ENS 50162 | 1 June 2014 18:14:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Technical Support Center Cooling Capability | At 1314 (CDT) on 6/01/2014, Technical Support Center ventilation alarm was received in the main control room. The Equipment Operator reported that the trouble alarm for the roof mounted condensing units was in alarm and the condensing units were tripped. Upon resetting the alarms the condensing units ran for three to five minutes and tripped again. This caused a loss of Technical Support Center cooling capability. Technical Support Center Air Handling system and filtration remain in operation. The room temperature is being monitored locally. Wet bulb temperature at 1500 (CDT) was reported to be 78.5 deg F. Corrective action process has been initiated. This event is reportable under 10CFR50.72(b)(3)(xiii) as described in NUREG-1022, Rev. 3 since this condition affects an emergency response facility. The licensee has notified the NRC Resident Inspector. | ||
| ENS 49723 | 16 October 2013 19:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service | On 10/16/2013 at 14:20 (CDT), the Technical Support Center (TSC) Emergency Makeup Filter Flow Control Damper (OVV145Y) was discovered degraded and non functional during planned maintenance activities. The degraded damper adversely impacted the TSC ventilation system function. On 10/16/2013 at approximately 15:00 (CDT), administrative actions were developed and briefed to isolate instrument air to the degraded nonfunctional damper OVV 145Y providing the capability to restore TSC Emergency Makeup Filter functionality. Isolating instrument air to the degraded damper places the damper in the failed open position, thereby restoring TSC Emergency Makeup Filter functionality. On 10/16/2013 at 20:25 (CDT), instrument air was isolated to the degraded damper OVV 145Y under administrative controls restoring TSC Emergency Makeup Filter functionality. This action was taken after determining no adverse affects on system operation. On 10/30/2013, degraded damper OVV145Y was repaired, instrument air restored and post maintenance testing completed, thereby restoring the degraded TSC emergency Makeup Filter Unit flow control damper functionality. This event is reportable per 10CFR50.72(b)(3)(xiii) for a major loss of emergency assessment capability because the emergent degraded TSC flow control damper OVV145Y adversely impacted the function of TSC Emergency Makeup Filter and was not restored within the TSC activation time (60 minutes). This event was originally determined not reportable because the capability to restore within the TSC activation time (60 minutes) existed from the time of discovery. Upon further review it was determined to be reportable because the degraded damper 0VV145Y was not restored to service within the TSC activation time (60 minutes). The licensee has notified the NRC Resident Inspector. | ||
| ENS 48328 | 21 September 2012 01:35:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Ventilation Inoperable | At 2035 CDT on 9/20/2012 power was removed from the Technical Support Center ventilation for planned maintenance on the supply breaker and the supply breaker cubicle. At 2109 CDTduring restoration, it was discovered that the breaker for the Technical Support Center ventilation could not be closed. The cause for not being able to close the supply breaker is unknown. Troubleshooting is currently in progress and the Technical Support Center ventilation is expected to be returned to service on 09/21/2012. This event is reportable under 10 CFR 50.72(b)(3)(xiii) as described in NUREG-1022, Rev.2 since this work activity affects an emergency response facility. The licensee has notified the NRC Resident Inspector. | ||
| ENS 47845 | 18 April 2012 02:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Plant Process Computer Removed from Service for Planned Replacement | At 2130 (CDT) on April 17, 2012, the Unit 1 Plant Process Computer (PPC) was removed from service for a planned replacement in the current Unit 1 Refueling Outage. The Unit 1 PPC feeds the Safety Parameter Display System (SPDS) used in the Main Control Room (MCR) and the Technical Support Center (TSC). The Unit 1 PPC also feeds the Emergency Response Data System (ERDS). The Unit 1 and Unit 2 PPCs also feed the Plant Parameter Display System (PPDS) used in the MCR, TSC and Emergency Operations Facility (EOF). Meteorological data will remain available in the MCR but not through ERDS for either Unit 1 or Unit 2. The dose assessment program will remain functional as the Unit 2 Plant Process computer will be capable of providing the necessary data through PPDS to run the program. The dose assessment program is not affected by the Unit 1 PPC being out of service. As compensatory measures, a proceduralized backup method to fax or communicate via a phone circuit applicable data to the NRC, TSC, and EOF exists. There is no impact to the Emergency Notification System (ENS) or Health Physics Network (HPN) communication systems. The new Unit 1 PPC is scheduled to be functional on April 21, 2012. However, based on the mode Unit 1 will be in, this will limit the number of points that would provide usable data. The Unit 1 PPC will be tested as mode changes occur. The Unit 1 PPC is planned to be declared functional by Mode 2. A follow-up ENS call will be made once the Unit 1 PPC is declared functional. The loss of SPDS and ERDS is a 'major loss of assessment capability' and is reportable under 10CFR50.72(b)(3)(xiii). The NRC Senior Resident Inspector and the State of Illinois (through the Illinois Emergency Management Agency Resident Inspector) have been notified of this ENS call.
As of 1035 EDT on May 15, 2012, the Unit 1 PPC is considered operational with respect to the Safety Parameter Display System (SPDS), Plant Parameter Display System (PPDS) and Emergency Response Data System (ERDS). Therefore, a Major Loss of Assessment Capability no longer exists on Unit 1. The EP Manager will contact the NRC Computer Center for Unit 1 to ensure the ERDS data is being satisfactorily sent to the NRC. The NRC Resident Inspector and the State of Illinois (through the Illinois Emergency Management Agency Resident Inspector) have been notified of this ENS update. The R3DO (Patty Pelke) has been notified. | Emergency Response Data System Safety Parameter Display System | |
| ENS 47622 | 26 January 2012 03:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service Due to Planned Maintenance | Planned preventive maintenance activities are being performed on the Braidwood Nuclear Station Technical Support Center (TSC) Ventilation System. These work activities are planned to be performed and completed expeditiously within 8 hours. This maintenance activity includes the performance of preventive maintenance on the TSC outside air supply fan unit which affects the TSC emergency filter train and air handling unit. During a portion of the time these activities are being performed, this equipment will not be available for operation. As such, the TSC Ventilation will be rendered non-functional during the performance of portions of the work activity. If an emergency condition occurs that requires activation of the Technical Support Center, during the time this work activity is being performed, it will take no more than 4 hours to return the equipment back to functional status, dependent on the stage of the work activity at the time an emergency occurs. Plans are to utilize the TSC for any declared emergency during the time this work activity is being performed as long as radiological conditions allow. This event is reportable per 10CFR50.72(b)(3)(xiii) as described in NUREG-1022, Rev. 2 since this work activity affects an emergency response facility for the duration of the maintenance. The licensee notified the NRC Resident Inspector.
Braidwood Nuclear Station TSC ventilation was restored to available status at 0635 CST on January 26, 2012. The previously reported system preventative maintenance has been completed. The licensee notified the NRC Resident Inspector. Notified R3DO (L. Kozak). | ||
| ENS 46766 | 19 April 2011 04:09:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Plant Process Computer Removed from Service for Planned Replacement | At 2309 (CDT) on April 18, 2011, the Unit 2 Plant Process Computer (PPC) was removed from service for planned replacement in the current Unit 2 refueling outage. The Unit 2 PPC feeds the Safety Parameter Display System (SPDS) used in the Main Control Room (MCR) and the Technical Support Center (TSC). The Unit 2 PPC also feeds the Emergency Response Data System (ERDS). The Unit 1 and Unit 2 PPCs also feed the Plant Parameter Display System (PPDS) used in the MCR, TSC and Emergency Operations Facility (EOF). Meteorological data will remain available. The dose assessment program will remain functional as the Unit 1 Plant Process computer will be capable of providing the necessary data through PPDS to run the program. The dose assessment program is not affected by the Unit 2 PPC being out of service. As compensatory measures, the backup method to fax or communicate via a phone circuit applicable data to the NRC, TSC and EOF exists. There is no impact to the Emergency Notification System (ENS) or Health Physics Network (HPN) communications systems. The new Unit 2 PPC is scheduled to be functional on April 23, 2011. However, based on the mode Unit 2 will be in, this will limit the number of points that would provide usable data. The Unit 2 PPC will be tested as mode changes occur. The Unit 2 PPC is planned to be declared functional by Mode 2. A follow-up ENS call will be made once the Unit 2 PPC is declared functional. The loss of SPDS and ERDS is a 'major loss of assessment capability' and is reportable under 10CFR50.72(b)(3)(xiii). The NRC Senior Resident Inspector and the State of Illinois (through the Illinois Emergency Management Agency Resident Inspector) have been notified of this ENS call.
As of 0815 CT on May 10, 2011, the Unit PPC is considered operational with respect to the Safety Parameter Display System (SPDS), Plant Parameter Display System (PPDS) and Emergency Response Data System (ERDS). Therefore, a Major Loss of Assessment Capability no longer exists on Unit 2. The EP Manager will contact the NRC Computer Center today to conduct an ERDS test for Unit 2 to ensure the data is being satisfactorily sent to the NRC. The NRC Resident Inspector and the State of Illinois (through the Illinois Emergency Management Agency Resident Inspector) have been notified of this ENS update. Notified R3DO(Passehl) | Emergency Response Data System Safety Parameter Display System | |
| ENS 43590 | 23 August 2007 20:30:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Manual Reactor Trip Because of Lowering Condenser Vacuum | At 1530 hours on 8/23/07, Braidwood Station Unit 2 was manually tripped due to lowering condenser vacuum. The lowering condenser vacuum resulted from the trip of two circulating water pumps. The cause of the two circulating water pump tripping is under investigation. All control rods inserted and there were no complications during the trip and all systems functions as required. Following the unit trip, the Auxiliary Feedwater System actuated as expected to maintain steam generator level. At the time of the unit trip, the Braidwood Station area was experiencing severe thunderstorms. Additionally, at 1604 hours, 19 of 70 emergency sirens for the Braidwood Station were declared inoperable due to a loss of power from storms in the area. As of 1704 hours, 19 sirens (greater than 25%) remain inoperable. This event is considered a major loss of offsite response capability and applies to both Braidwood Station Unit 1 and Unit 2. These events are is being reported under: (1) 10 CFR 50.72(b)(2)(iv)(B) as an event that results in the actuation of the reactor protection system (RPS) when the reactor is critical, (2) 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the PWR auxiliary feedwater system. (3) 10 CFR 50.72(b)(3)(xiii) as a major loss of offsite response capability. All safety buses remained powered by offsite power throughout this event. Emergency diesel generators are available if needed. No steam generator PORV's lifted as a result of the trip. Decay heat is being discharged to the condenser via the steam dumps. The licensee informed the NRC Resident Inspector. | Steam Generator Reactor Protection System Emergency Diesel Generator Auxiliary Feedwater Control Rod | |
| ENS 43137 | 1 February 2007 15:25:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Offsite Phone Connections | At approximately 0925 CST, Braidwood lost approximately 85% of phone functionality. The loss of phones has been determined to be an off site issue and the local phone company is investigating the situation. The Emergency Response Organization (ERO) can still activate ERO pagers using cell phones. The Shift Manager has a dedicated cell phone. The licensee notified the NRC Resident Inspector.
The licensee declared the ENS and commercial lines operable based on testing and information from the telephone company. The R3DO (Hills) has been notified. | ||
| ENS 41858 | 21 July 2005 00:17:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Emergency Sirens Failed for One Hour | At 2017 CDST on July 20, 2005, it was determined that greater than 25% of Braidwood Station Emergency Sirens, which are maintained by others, had been failed for one hour. The initial failure occurred at 1917 CDST on July 20, 2005, and was apparently caused by storm activity in the area. At 2041 CDST on July 20, 2005, Braidwood Station was notified by the Corporate Emergency Planning organization that the number of failed Emergency sirens was less than 25% of the total number of sirens, and that sirens were in the process of being restored at that time. This notification is required by 10CFR 50.72(b)(3)(xiii) The licensee notified the NRC Resident Inspector. | ||
| ENS 40922 | 4 August 2004 12:15:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Notification Due to Inoperable Sirens | At 0715 on August 4, 2004, Exelon was notified by Fulton Contracting that Braidwood Station had >(greater than) 25% of its emergency notification sirens inoperable. The cause of the inoperability (at 0626) for the sirens was due to a loss of power due to severe weather. As of 0708 on August 4, 2004, the number of inoperable sirens was less than 25%. Due to a major loss of emergency preparedness capabilities, this event is reportable per 10 CFR 50.72(b)(3)(xiii). The licensee notified the NRC Resident Inspector. |