Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56487 | 26 April 2023 06:15:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification - Spilled Sodium Hypochlorite | The following information was provided by the licensee via email: On 4/25/2023 at approximately 2315 (MST) it was reported that there was possible sodium hypochlorite actively leaking near the 'A' essential spray pond (ESP). Upon investigation, it was determined that the 'low flow' line of sodium hypochlorite supply to the 'A' spray pond had developed a leak. Sodium hypochlorite had pooled at the leak location and subsequently run down the ESP apron, into the road, and into the storm drain located in the protected area fence. An estimate of approximately 300 gallons of spilled sodium hypochlorite was determined based on the time frame that the sodium hypochlorite was scheduled to start injecting into the 'A' spray pond and the time the leak was isolated. The leak was isolated on 4/25/2023 at approximately 2330. The leak was contained in the storm drain with the storm gates closed, therefore nothing was released offsite. The cleanup effort in progress includes diluting the sodium hypochlorite with domestic service water, collecting it into the storm drain, pumping it to a tank truck, and transporting it to the Palo Verde Water Resources Facility for neutralization. Condition Report 23-04519 was generated to document the leak. The Palo Verde Senior Environmental Scientist was notified and subsequently informed the Environmental Protection Agency (EPA) National Response Center (NRC#1365638) on 4/26/23 at 0005 in accordance with the 91DP-0EN03 Environmental Spill Response (local procedure). The NRC Senior Resident Inspector was also notified. No personnel were injured and no equipment was damaged as a result of the spill. The Palo Verde Fire Department was notified and the area was barricaded off to prevent personnel from entering the area during the cleanup effort. | Service water Spray Pond | |
| ENS 55796 | 19 March 2022 20:06:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Technical Support Center (TSC) | The following information was provided by the licensee via email: The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. At 1306 (MST) on March 19, 2022, the Technical Support Center (TSC) lost normal and alternate electrical power, resulting in the inability to perform emergency assessments at the TSC. At the time of the event, the normal power source to the TSC (offsite power) was under a clearance for maintenance activities and the alternate power source (backup generator) was running to provide electrical power to the TSC. At 1306, the alternate power source to the TSC was lost when the backup generator tripped. Power was restored to the TSC via the normal power source at 1723. The cause of the TSC backup generator trip is unknown at this time. All three units are stable and in Mode 1. No emergency classification was required per the Emergency Plan. The NRC Senior Resident Inspector has been informed. | ||
| ENS 55444 | 1 September 2021 03:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Seismic Monitoring System | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73. On 8/31/21 at 2050 (MST), the Seismic Monitoring System was discovered Non-Functional. This constitutes an unplanned loss of emergency assessment capability for an operational basis earthquake. There is currently no seismic activity in the area according to the U.S. Geological Survey. The NRC Resident Inspector was notified of the loss of seismic monitoring capability. | ||
| ENS 55205 | 22 April 2021 16:25:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Inadvertant Activation of Emergency Sirens | At 0925 Mountain Standard Time (MST) on April 22, 2021, Palo Verde Nuclear Generating Station staff received reports that Emergency Notification sirens were activated. Current information indicates that the inadvertent activation of the sirens was caused by an offsite agency during performance of a planned silent test that occurred at approximately 0916 MST. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). All sirens remain functional, and the NRC Resident Inspectors have been notified of the issue. Additional notifications will be made as needed. | ||
| ENS 54272 | 12 September 2019 01:24:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Main Steam Line Radiation Monitor Communication Failure | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. Radiation monitor RU-140 (#2 Steam Generator Main Steam Line radiation monitor) experienced a communication failure on both ports A and B. The RU-140 monitor is off line and non-functional at this time. At least one channel of RU-140 is required to perform a Steam Generator Tube Rupture (SGTR) dose assessment. This represents an unplanned loss of radiological assessment capability for the inability to perform dose assessments that require the radiation monitor. The ability to make emergency classifications from other radiological data collection methods such as field sampling remains available. Actions have been initiated to restore the radiation monitor. The NRC Resident Inspector has been informed. | Steam Generator Main Steam Line | |
| ENS 53702 | 29 October 2018 07:00:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification of Non- Work Related Fatality | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. At approximately 03:30 MST on October 29, 2018, an Arizona Public Service Company (APS) employee developed a personal medical condition in the Owner Controlled Area outside of the Secured Owner Controlled Area at Palo Verde Generation Station (PVGS). PVGS Emergency Medical Technicians responded and transported the individual to an offsite emergency trauma center. Upon arrival at the trauma center, medical personnel declared the individual deceased at approximately 05:35 MST. The fatality was not work related and the individual was outside of the Radiological Controlled Area and no radioactive material or contamination was involved. No news release by APS is planned. Notifications were made to the Arizona Division of Occupational Safety and Health at 08:15 MST. The NRC Resident Inspectors have been notified. | ||
| ENS 53575 | 31 August 2018 07:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unplanned Loss of Steam Line Monitor Channels | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) as a Loss of Emergency Preparedness Capabilities at Palo Verde Nuclear Generating Station (PVNGS) Unit 2. On August 31, 2018, at approximately 0544 Mountain Standard Time (MST), the Unit 2 control room experienced an unplanned loss of Steam Generator #1 steam line monitor (RU-139), Channels A and B. This main steam line monitor is used in the PVNGS Emergency Plan to perform dose assessment in the event of a steam generator tube rupture. The NRC Resident Inspectors have been notified. | Steam Generator Main Steam Line | |
| ENS 53522 | 23 July 2018 07:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unplanned Loss of Steam Line Monitor Channels | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS (Emergency Notification System) or under the reporting requirements of 10CFR50.73. This event is being reported pursuant to 10CFR50.72(b)(3)(xiii) as a Loss of Emergency Preparedness Capabilities at Palo Verde Nuclear Generating Station (PVNGS) Unit 2. On July 23, 2018, at approximately 1631 Mountain Standard Time (MST), the Unit 2 control room experienced an unplanned loss of Steam Generator #1 steam line monitor (RU-139), channels A and B. This monitor is used to assess dose projections for Main Steam line exhaust while in Modes 1-4 and is used in the PVNGS Emergency Plan to perform classification of Initiating Conditions 'RS1' and' RG1' and Emergency Action Levels (EALs) 'RS1.2' and 'RG1.2'. The PVNGS Emergency Plan does have two additional EALs that can be assessed for each Initiating Condition. The loss of this monitor constitutes a reportable loss of emergency assessment capability. The NRC Resident Inspector has been informed of this condition. | Steam Generator Main Steam Line | |
| ENS 53215 | 16 February 2018 04:53:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Automatic Reactor Trip Due to Low Departure from Nucleate Boiling Signal | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On February 15, 2018, at approximately 2153 Mountain Standard Time (MST), the Palo Verde Nuclear Generating Station (PVNGS) Unit 1 Control Room received Reactor Protection System alarms for Low Departure from Nucleate Boiling Ratio and an automatic reactor trip occurred. Prior to the reactor trip, Unit 1 was operating normally at 100 percent power. Plant operators entered the emergency operations procedures and diagnosed an uncomplicated reactor trip but noted that Reactor Coolant Pumps 1B and 2B were not running due to a loss of power. All CEAs (Control Element Assemblies) fully inserted into the core. Following the reactor trip, all nuclear instruments responded normally. No emergency classification was required per the PVGS Emergency Plan. The PVGS Unit 1 safety related electrical busses remained energized from normal offsite power during the event. The Unit 1 'B' Diesel Generator is currently removed from service for maintenance. Due to ongoing planned maintenance on NAN-X02, Startup Transformer 2, fast bus transfer for NAN-S02 (from NAN-S04) was blocked. This resulted in a loss of offsite power to NAN-S02 and NBN-S02. The offsite power grid is stable. Unit 1 is currently stable in Mode 3 with the reactor coolant system at normal operating temperature and pressure. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant or the health and safety of the public. The NRC Resident Inspector has been informed of the Unit 1 reactor trip.
Unit 1 is stable in Mode 3 following an uncomplicated trip. Offsite power has been restored to non-safety related electrical busses. Troubleshooting continues to determine the cause of the event. During performance of the alarm response procedure, it was identified that the seismic monitoring (SM) system had been in alarm since the reactor trip and was incapable of performing its emergency plan function. Pursuant to 10 CFR 50.72(b)(3)(xiii), this condition constitutes a major loss of emergency assessment capability. Compensatory measures have been implemented in accordance with PVNGS procedures to provide alternative methods for HU2.1 event classification with the SM system out of service. Maintenance is currently in progress to restore SM system functionality. The licensee notified the NRC Resident Inspector. Notified R4DO (Werner).
Station staff completed an evaluation of event EN #53215 reported on February 15, 2018, and determined that the seismic monitoring system remained capable of assessing a seismic event following the reactor trip. Therefore, a major loss of emergency assessment capability pursuant to 10 CFR 50.72(b)(3)(xiii) did not occur as reported in the update on February 16, 2018. The NRC Resident Inspectors have been notified. Notified the R4DO (Gaddy). | Reactor Coolant System Reactor Protection System | |
| ENS 52989 | 22 September 2017 22:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitoring Computer Out-Of-Service | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) for a major loss of emergency assessment capability at the Palo Verde Nuclear Generating Station (PVNGS). On September 21, 2017 at 0915 MST, the seismic monitoring (SM) computer was declared non-functional for the performance of a planned surveillance test. On September 21, 2017 at 1201 MST, the SM system computer became non-responsive during the performance of the test. Control room staff attempted to reboot the computer and were unsuccessful. Maintenance and troubleshooting efforts began thereafter to initiate repairs. As a compensatory measure, PVNGS procedures for seismic event evaluation provide alternative methods for event classification of a seismic event with the SM system out of service. The SM system functions to provide indication that the Operational Basis Earthquake (OBE) threshold has been exceeded following a seismic event and is used in the PVNGS Emergency Plan to perform classification of Initiating Condition 'Seismic event greater than OBE levels' and Emergency Action Level HU2.1. On September 22, 2017 at 1500 MST, maintenance personnel performing software repair efforts determined hardware replacement is required. The required component will not be available before 72 hours from the start of the event. Because the SM system is not expected to be restored within 72 hours, this condition is being reported as a planned event constituting a major loss of emergency assessment capability with viable compensatory measures in place. The NRC Resident Inspector has been informed of this condition. | ||
| ENS 52229 | 9 September 2016 01:56:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of the Seismic Monitoring System Computer | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) for a loss of emergency assessment capability at the Palo Verde Nuclear Generating Station (PVNGS). On September 8, 2016 at 1856 (MST), seismic monitoring (SM) system computer AJSMNXYQI0001**INSTRU was determined to be non-functional due to a power spike which caused a temporary loss of power to the seismic instrumentation and resulted in a locked in the Control Room alarm. At 2305, I&C technicians re-booted the computer and verified the SM system was functioning. On September 8, 2016, at approximately 2353, further review of this equipment failure and the related impact to the capability of the SM system determined that this was a reportable loss of emergency assessment capability during the period between 1856 and 2305. This specific SM functions to provide indication that the Operational Basis Earthquake threshold has been exceeded following a seismic event and is used in the PVNGS Emergency Plan to perform classification for emergency action level HA1.1, Natural or Destructive Phenomena affecting Vital Areas. As a compensatory measure, PVNGS procedures for seismic event evaluation provide alternative methods for HA1.1 event classification with the SM out of service. Maintenance to correct the condition has been completed. The NRC Resident Inspector has been informed of this condition. | ||
| ENS 51844 | 2 April 2016 05:29:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Sodium Hypochlorite Spill on Site | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. At approximately 2229 (MST) on April 1, 2016, Arizona Public Service Company completed an offsite notification to the Environmental Protection Agency's National Response Center to report a spill of approximately 8000 gallons of sodium hypochlorite (8% solution) in the vicinity of the Unit 3 cooling towers at the Palo Verde Nuclear Generating Station (PVNGS). Additional notifications were made to Arizona State and Maricopa County environmental authorities. The Unit 3 cooling towers are located in the Security Owner Controlled Area at PVNGS and are outside of the protected area. The leak, which resulted from a failed hose on the main hypochlorite distribution header, was stopped by closing a valve to isolate the header. The immediate area has been barricaded. The quantity released exceeded the Reportable Quantity for sodium hypochlorite (RQ of 100 pounds) and was therefore reported. There was no impact to the operation of the PVNGS units or personnel onsite or offsite. The NRC Senior Resident has been notified. | ||
| ENS 51041 | 4 May 2015 10:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitoring System Out of Service | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) for a loss of emergency assessment capability at the Palo Verde Nuclear Generating Station (PVNGS). On May 4, 2015 at 0320, seismic monitoring (SM) system force balance accelerometer R0006 was determined to be non-functional due to an emergent equipment failure. On May 4,2015, at approximately 1600, further review of this equipment failure and the related impact to the capability of the SM system determined that this was a reportable loss of emergency assessment capability. This specific accelerometer functions to provide indication that the Operational Basis Earthquake threshold has been exceeded following a seismic event and is used in the PVNGS Emergency Plan to perform classification for emergency action level HA1.1, Natural or Destructive Phenomena affecting Vital Areas. As a compensatory measure, PVNGS procedures for seismic event evaluation provide alternative methods for HA1.1 event classification with accelerometer R0006 out of service. Maintenance to correct the condition is in-progress. The NRC Resident Inspector has been informed of this condition. | ||
| ENS 50984 | 15 April 2015 02:20:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Sodium Hydroxide Spill Onsite Exceeding Reportable Quantity | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. Arizona Public Service Co. made an offsite notification to the National Response Center regarding an approximately 3500 gallon caustic (8% sodium hydroxide) spill due to an improper valve lineup. The spill occurred at the Water Reclamation Facility (produces water for cooling towers and power plant and is located outside the Security Owner Controlled Area) in the area of the Fire Protection tanks (additional liquid was contained in a containment structure at the release location, and in a nearby concrete lined storm ditch on site). The release has been isolated, the immediate area has been barricaded. The quantity released exceeded the Reportable Quantity for sodium hydroxide (RQ of 1,000 pounds) and was therefore reported. Additionally, the state (Arizona) and county (Maricopa) have also been notified. There was no impact to the operation of the power units, aquifer or personnel onsite or offsite. The NRC Resident (Inspector) has been notified. | ||
| ENS 49616 | 8 December 2013 15:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Assessment Due to Technical Support Center Uninterruptable Power Supply Planned Replacement | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. At approximately 0800 Mountain Standard Time on December 8, 2013, Palo Verde Nuclear Generating Station (PVNGS) removed the Technical Support Center (TSC) uninterruptable power supply (UPS) from service for a planned replacement. The outage disables the Emergency Response Facility Data Acquisition and Display System (ERFDADS) inside the TSC, remote meteorological data display in the emergency response facilities and control rooms, and transmission of plant data to the Emergency Operations Facility (EOF) and to the NRC's Emergency Response Data System (ERDS). The outage is expected to be completed within five days. The TSC and EOF remain functional during the outage. The outage does not affect the availability of normal power to the TSC or back-up power from the TSC diesel generator. Existing telecommunication systems provided for the emergency response organization (ERO) remain functional to provide the ERO within the TSC and EOF the necessary emergency assessment capabilities, as described in the PVNGS Emergency Plan. The ERFDADS system in each of the three unit control rooms and unit satellite TSCs remain functional and are not affected by the TSC UPS outage. Compensatory measures exist within emergency plan implementing procedures to obtain meteorological tower data locally and from the National Weather Service. The ERO has been briefed on the effects of the planned TSC UPS outage. The NRC Resident Inspector has been informed. PVNGS will inform the NRC after the outage has been completed and the functionality of affected equipment has been restored.
The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. This notification is an update to EN 49616 which provided notification of pre-planned maintenance activities on the Palo Verde Nuclear Generating Station (PVNGS) Technical Support Center (TSC) uninterruptable power supply (UPS) that disabled various Emergency Plan (E-Plan) data systems. At approximately 0915 Mountain Standard Time on December 12, 2013, PVNGS restored the affected data systems to service such that the functions of the E-Plan can now be performed without the use of alternate methods. The NRC Resident Inspector has been informed. Notified R4DO (Werner). | Emergency Response Data System | |
| ENS 49482 | 29 October 2013 13:05:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Employee Fatality | At approximately 0530 MST on October 29, 2013, an Arizona Public Service Company (APS) employee developed a personal medical condition in the Owner Controlled Area prior to entering the Protected Area at the Palo Verde Nuclear Generation Station (PVNGS). PVNGS Emergency Medical Technicians responded and transported the individual to an offsite emergency trauma center. Upon arrival at the trauma center, medical personnel declared the individual deceased at 0650 (on 10/29/13). The fatality was not work related and the individual was outside of the Radiological Controlled Area. No radioactive material or contamination was involved. No news release by APS is planned. Notifications to the Arizona Division of Occupational Safety and Health, and the Maricopa County Sheriff's Office are planned. The NRC Resident Inspectors have been notified. | ||
| ENS 48849 | 25 March 2013 17:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | One Alert Notification Siren Removed from Service for Planned Maintenance | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On March 25, 2013, at 10:30, Mountain Standard Time, Palo Verde Nuclear Generating Station (PVNGS) removed Alert Notification System (ANS) Siren 22 from service for planned maintenance. Siren 22 provides notification to approximately 1455 members of the public within five miles of PVNGS. Siren 22 is expected to be returned to service on March 27, 2013. County authorities have been notified of this planned maintenance activity and appropriate contingency measures have been established to compensate for the non-functional siren. The PVNGS Emergency Plan contains contingencies for notification of members of the public within the affected area during an emergency when a siren is out of service. There are no events in progress that require ANS operation. The NRC Resident Inspector and the Maricopa County Sheriff's Office have been notified. | ||
| ENS 48347 | 26 September 2012 20:36:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Attempted Entry Onto the Site by an Illegal Alien with False Identification | This event is being reported as a newsworthy concern to the public under 10 CFR 50.72(b)(2)(xi). All times listed are approximate Mountain Standard Time. On September 26,2012, at 13:36 pm, Arizona Public Service (APS) was notified of the intention of Maricopa County Sheriff's Office (MCSO) to issue a press release regarding an attempted entry to the Palo Verde Nuclear Generating Station's (PVNGS) Security Owner Controlled Area (SOCA) by an individual with suspicious identification earlier this morning. An individual employed with a construction project sub-contractor arrived at the SOCA checkpoint and presented suspicious identification to PVNGS security officers to gain access to the site. The individual was not admitted through the checkpoint into the SOCA. MCSO was notified and placed the individual into custody. MCSO determined the identification was false and the individual was an undocumented immigrant. The individual did not enter nor was he previously granted access to the site's Protected Areas surrounding the three units and Independent Spent Fuel Storage Installation. No evidence of malicious intent has been identified. MCSO is investigating the incident. The station notified NRC Resident Inspectors and Region IV staff of the condition. APS does not intend at this time to issue a press release, but is responding to media inquiries. | ||
| ENS 47688 | 23 February 2012 01:45:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Suspicious Package Discovered on Site | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73 At 1852 hours, Palo Verde Unit 1 was notified of a suspicious package located in the Owner Controlled Area outside the Protected Area. Maricopa County Sheriff's Office was contacted for assistance with a bomb disposal unit. Local media has become aware of this event and expressed interest by dispatching helicopters and television crews. There are no safety systems impacted by the package and operations personnel are not hampered in their ability to operate safety related equipment. There is no release of radioactivity to the environment as a result of this package and it has not adversely affected the safe operation of the plant or health and safety of the public. All three Palo Verde units are being maintained stable at approximately 100% power. The NRC Resident Inspector has been notified.
The Maricopa County Sherriff's Office bomb disposal unit responded and inspected the package. The suspicious package contained a granular absorbent material, similar to that used to clean liquid spills. The event was terminated at 23:02 AZ MST (on 2/22/12). The NRC Resident Inspector has been updated." Notified the R4DO (Deese). | ||
| ENS 47333 | 8 October 2011 23:19:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Notification of Unusual Event Due to Severe Electrical Fault in Rcp Junction Box | Reactor Coolant Pump 2A tripped at approximately 1535 MST, resulting in numerous simultaneous electrical distribution alarms. A walkdown of containment was performed and at 1609 MST it was determined that a junction box, supplying power to the 2A Reactor Coolant Pump, had failed, resulting in the pump tripping on overcurrent protection and an 86 lockout. The plant was operating in forced circulation and had one train of shutdown cooling in service. As a result, an Emergency Classification of HU2.2, Explosion was declared due to the junction box failure and noise that had been heard in containment. The plant is currently stable with one train of shutdown cooling in service, the opposite train of shutdown cooling is available to be placed in service. The Unit 1 Reactor Coolant System is currently at 160 degrees Fahrenheit and 375 psia with the 1A Reactor coolant pump in service for forced circulation. The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. The NRC Resident Inspector has been notified. The licensee has notified appropriate state and local agencies.
The Notification of Unusual Event at Palo Verde Unit 1 was terminated at 1916 MST on 10/8/2011. The termination was based on conducting inspections which did not reveal any additional damage or plant impact as a result of this event. Unit 1 remains stable in Mode 5 with RCPs 1A and 1B in service along with one train of RHR in service. The licensee notified the NRC Resident Inspector and appropriate state and local agencies. Notified R1DO (Gray), NRR EO (Hiland), IRD (Grant), DHS (Flinter), and FEMA (Castro). | Reactor Coolant System Shutdown Cooling | |
| ENS 47274 | 18 September 2011 15:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service Due to Planned Maintenance | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. This report is being made under 10 CFR 50.72(b)(3)(xiii) for unavailability of the Palo Verde Technical Support Center (TSC). On September 18, 2011, from approximately 0830 to 1700 MST, a scheduled power outage will cause the TSC to be non-functional due to the loss of lighting, ventilation, Emergency Response Facilities Data Acquisition and Display System (ERFDADS), and the Plant Information (PI) System in the TSC. Temporary lighting will be installed prior to the power outage. In the event that the TSC is required to be activated, the Emergency Response Organization (ERO) will respond to the TSC and the electrical maintenance group will stop maintenance activities and restore power. The TSC will then be declared functional after power is restored. In addition, due to the power outage to the TSC, PI and ERFDADS will be unavailable at the Emergency Operations Facility. The NRC Resident Inspector has been notified of the planned power outage. * * * UPDATE FROM MIKE KOHART TO JOHN KNOKE AT 2200 EDT ON 9/18/11 * * * At 2200 EDT the Palo Verde Technical Support Center (TSC) has been restored to service This includes Emergency Response Facilities Data Acquisition and Display System (ERFDADS), and the Plant Information (PI) System. The licensee has notified the NRC Resident Inspector. Notified the R4DO (Pick). | ||
| ENS 47268 | 14 September 2011 17:23:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Two Public Warning System Sirens | On September 12, 2011, the Palo Verde Emergency Preparedness Department discovered that public warning system siren 1 was not responding and was out of service. The loss of this siren did not constitute a loss of capability to alert a large segment of the population for greater than one hour and was therefore, not reported. Troubleshooting had commenced but was not completed. On September 14, 2011, at 1023 Mountain Standard Time, the Palo Verde Emergency Preparedness Department was notified by Maricopa County Sheriff's Office (MCSO) that siren 6 had failed. Since siren 1 remains out of service pending repairs, and siren 6 is now out of service, the loss of the two sirens constitutes a loss of capability to alert a large segment of the population for greater than one hour and is reportable. This is a reportable event as a loss of communication and assessment capability that could potentially impact a population of greater than 10 percent of the people in the 10-mile emergency planning zone (approximately 750 people affected). Therefore, this notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii). If an event occurs while the sirens are out of service, the Palo Verde Emergency Plan has a contingency for dispatching MCSO vehicles with loudspeakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. Troubleshooting to determine the cause of the failure of siren 6 has also commenced. The NRC Resident Inspector has been notified of the out of service sirens and this ENS call. | ||
| ENS 47050 | 14 July 2011 21:11:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | News Release Regarding Arrest of Illegal Immigrant Working at Palo Verde | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. This event is being reported as a newsworthy concern to the public under 10 CFR 50.72(b)(2)(xi). Palo Verde Nuclear Generating Station (PVNGS) was notified that the Maricopa County Sheriff's Office (MCSO) issued a news release at 1411 on July 14, 2011, regarding entrance to the PVNGS site property by an individual who MCSO alleged to be an undocumented immigrant. The individual had entered Palo Verde's Security Owner Controlled Area on July 13, 2011, but was not granted access to the site's Protected Areas surrounding the three units and Independent Spent Fuel Storage Installation. PVNGS Security contacted MCSO to validate the identification card furnished by the individual at the Security Owner Controlled Area. MCSO determined the identification card to be suspicious, responded to the site, detained the individual, and transported him off-site for questioning. The station notified NRC Resident Inspectors and Region IV staff of the condition on July 13, 2011. Arizona Public Service is planning to issue a news release and is responding to media inquiries regarding the matter. | ||
| ENS 46634 | 22 February 2011 16:09:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Loss of Potable Water Supply | Arizona Public Service Co. made an offsite notification to the Maricopa County Environmental Services Division at 0909 MST on February 22, 2011, to report a loss of power to the Palo Verde Nuclear Generating Station drinking water supply pumps which resulted in the depressurization of the site domestic water supply header. The pumps were out of service on February 21, 2011, between the hours of 2001 and 2300 MST. Full service has been restored. The loss of power was related to the loss of Startup Transformer A-E-NAN-X02 as reported in ENS #46633 at 0023 on February 21, 2011. The NRC Resident Inspectors have been notified. | ||
| ENS 46331 | 14 October 2010 16:15:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Emergency Sirens Will Be Taken Out of Service for Planned Maintenance | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. From October 14, 2010 to October 22, 2010, Palo Verde personnel will be performing maintenance on public prompt notification system sirens. Sirens will be removed from service one at a time, and then each will be restored prior to continuing to the next siren. Siren #36 provides notification to approximately 470 members of the public within five miles of Palo Verde. Siren #23 provides notification to approximately 614 members of the public within five miles of Palo Verde. Siren #25 provides notification to approximately 335 members of the public within five miles of Palo Verde. Siren #18 provides notification to approximately 586 members of the public within five miles of Palo Verde. Siren #15 provides notification to approximately 1133 members of the public within five to ten miles of Palo Verde. Siren #22 provides notification to approximately 1015 members of the public within five miles of Palo Verde. Siren #17 provides notification to approximately 1196 members of the public within five miles of Palo Verde. Each of these are considered by Palo Verde to be a 'large segment of the population.' This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii). The Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. There are no events in progress that require siren operation. A follow-up call will be placed when the affected sirens are returned to service. The NRC Resident Inspector has been notified of the siren maintenance and this ENS call.
Maintenance on the Palo Verde public prompt notification sirens listed on ENS #46331 has been completed. The sirens are operable and are back in service. The NRC Resident Inspector has been notified of the siren maintenance and this ENS call. Notified R4DO (Proulx). | ||
| ENS 46188 | 18 August 2010 14:42:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Several Public Warning System Sirens | On August 18, 2010, at approximately 0742 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department discovered that public warning system sirens Nos. 17, 23, and 34 were not responding, and therefore, were out of service. The loss of these sirens could potentially impact a population of approximately 1800 people in the 5-mile emergency planning zone (EPZ). Since the loss of these sirens could impair Arizona Public Service Company's ability to inform greater than 5% of the population within the EPZ, this notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii). If an event occurs while the sirens are out of service, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. Troubleshooting to determine the cause of the failure has commenced. The NRC Resident Inspector has been notified of the out of service sirens and this ENS call. (At the time of the notification to the NRC), siren #23 was restored at 1316 MST. The out of service sirens are now Nos. 17 and 34 with an affected population of 1196 within the 5 mile EPZ.
The licensee restored siren #17 at 1647 MST on 8/18/10. The restoration of this siren provided coverage to all the population within the 5-mile EPZ. The licensee has notified the NRC Resident Inspector and will also notify State and local authorities. R4DO (Miller) notified. | ||
| ENS 46140 | 30 July 2010 14:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Siren | On July 30, 2010, at approximately 0720 Mountain Standard Time (MST), the Palo Verde Emergency Planning Department discovered that public warning system siren No. 17 was not responding, and therefore, is out of service. The loss of siren No. 17 could potentially impact a population of approximately 1196 people in the 5-mile emergency planning zone (EPZ). Since the loss of siren No. 17 could impair Arizona Public Service Company's ability to inform greater than 5% of the population within the EPZ, this notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii). If an event occurs while siren No. 17 is out of service, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. Troubleshooting to determine the cause of the failure has commenced. The NRC Resident Inspector has been notified. | ||
| ENS 45968 | 1 June 2010 14:15:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Public Warning System Siren Out of Service | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On June 01, 2010, at approximately 0715 Mountain Standard Time (MST), the Palo Verde Emergency Planning Department discovered that public warning system siren No. 17 was not responding, and therefore, is out of service. The loss of siren No. 17 could potentially impact a population of approximately 1196 people in the 5-mile Emergency Planning Zone (EPZ). Since the loss of siren No. 17 could impair Arizona Public Service Company's ability to inform greater than 5% of the population within the EPZ, this notification is being made in accordance with 10 CFR 10.72(b)(3)(xiii). If an event occurs while siren No. 17 is out of service, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. The NRC Resident Inspector has been notified of siren No. 17 being out of service and this ENS call.
Siren number 17 was returned to service at 1435 MST. The NRC Senior Resident Inspector has been notified. The remote radio was replaced and all post-maintenance testing was completed. Notified R4DO (Werner). | ||
| ENS 45425 | 11 October 2009 11:50:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Reactor Water Level Indication Inoperable | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS (Emergency Notification System) or under the reporting requirements of 10CFR50.73. On 10/11/2009 at 0450 MST Palo Verde Nuclear Station Unit 1 declared both trains of the Qualified Safety Parameter Display (QSPDS) inoperable due to the discovery that an installed temporary modification (TMOD) impacted the reactor vessel level indication parameter in a non-conservative manner. The modification jumpered failed heater junction thermal connections (HJTC) at the heated and unheated HJTC points. Unit 1 has two failed detectors with TMODs installed. During a design event where these detectors would be needed, these detectors will not alarm at the correct vessel levels. The emergency operating procedures use this indication and pressurizer level indications (which are unaffected by this condition) to throttle safety injection flow during certain accidents. With the TMOD providing incorrect indication the operators could throttle flow when full flow should be maintained. In addition the QSPDS reactor level indication is used in the Emergency Plan to classify emergencies. The standard Appendix 101 to Palo Verde emergency procedures provides guidance for an alternate method for determining reactor vessel level when RVLMS (Reactor Vessel Level Monitoring System) is out of service. This alternate method determines level by manually determining sub-cooled, saturation or superheated conditions based upon input of reactor vessel pressure and the "raw" QSPDS - RVLMS thermocouple temperature indications. This compensatory measure ensures that classification of events can continue to be completed in a timely manner. Unit 1 has entered the LCO (Limiting Condition of Operation) required action for this condition which requires at least one channel be restored to operable status within 7 days. Unit 2 is in a refueling and is not impacted at this time. Unit 3 does not have the TMOD installed. According to the licensee Train A TMOD which was installed 2/3/08 and the train B TMOD which was installed 12/12/08. The licensee checked the installation of these TMODs after reviewing operating experience reports from Calvert Cliffs. The licensee has notified the NRC Resident Inspector.
On 10/11/2009 at 12:26 MST Palo Verde Nuclear Station Unit 1 reported the inoperability of both trains of the Qualified Safety Parameter Display System (QSPDS) due to the discovery that an installed temporary modification impacted the reactor vessel water level indication parameter in a non-conservative manner. After further Operations and Engineering review it was concluded that the modification, installed due to one inoperable heated junction thermal couple (HJTC) in each train, does not result in the inoperability of either train of QSPDS since the Technical Specification required number of heated junction thermal couples (HJTC) (two each in the upper and lower level indication) remain operable with the temporary modification installed. In addition, the Control Room operators would understand the QSPDS indication and would correctly control the plant per the emergency operating procedures using this indication along with pressurizer level indication to throttle safety injection flow during certain accidents. The QSPDS reactor level indication is also used in the Emergency Plan to classify emergencies and the modification would not impact this function. Unit 1 has exited the LCO Condition for two inoperable QSPDS reactor vessel water level instrument channels. The licensee has notified the NRC Resident Inspector. R4DO (Okeefe) notified. | Qualified Safety Parameter Display System | |
| ENS 44924 | 21 March 2009 16:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Various Control Room Annunciators and Alarms Out of Service Due to Maintenance on Power Supply | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On March 21, 2009, from approximately 09:00 Mountain Standard Time (MST) until 14:00 MST, Palo Verde maintenance personnel will be performing scheduled maintenance to repair one of two redundant 120 VAC power supplies in Unit 2 that provides power to various alarms in the main control room. This work will require both power supplies to be de-energized resulting in approximately 50 percent of the Unit 2 plant annunciators being unavailable. The following compensatory measures will be in place for the duration of the scheduled work: Other assessment indications will remain available:
Plant Monitoring System
Qualified Safety Parameter Display System
Emergency Response Facility Data Acquisition System
No changes in plant power or operating mode are planned.
A third licensed operator will be in the control room.
The NRC Resident Inspector has been notified of the scheduled outage and this ENS call.
The power supply was successfully repaired and all annunciators were restored to normal as of 1515 MST. The Licensee will notify the NRC Resident Inspector. Notified R4DO (Hay) and NRR EO (Holian). | Qualified Safety Parameter Display System | |
| ENS 44692 | 2 December 2008 23:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of One (1) Emergency Siren | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On December 2, 2008, at approximately 1620 Mountain Standard Time (MST), the Palo Verde Emergency Planning Department discovered that public warning system siren No. 17 was not responding, and therefore, is out of service. The loss of siren No. 17 could potentially impact a population of approximately 1106 people in the 5-mile emergency planning zone (EPZ). Since the loss of siren No. 17 could impair Arizona Public Service Company's ability to inform greater than 5% of the population within the EPZ, this notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii). If an event occurs while siren No. 17 is out of service, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area. The MCSO is prepared to implement this contingency should it become necessary. Troubleshooting to determine the cause of the failure will start tomorrow morning (December 3, 2008). The NRC Resident Inspector has been notified of siren No. 17 being out of service and this ENS call.
Siren 17 was returned to service on Wednesday, December 3, 2008, at 0829 MST. Notified R4DO (Proulx). | ||
| ENS 44606 | 28 October 2008 16:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Maintenance on Public Prompt Notification System Emergency Sirens | The following event description is based on information currently available. If through subsequent reviews of the event, additional information is identified that is pertinent to this event or alters the information being provided at the time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. From October 28, 2008 until October 31, 2008, Palo Verde personnel will be performing maintenance on public prompt notification system sirens. One siren at a time will be removed from service, and will be restored prior to continuing to the next siren. Siren #42 provides notification to approximately 558 members of the public within 5 miles of Palo Verde. Siren #44 provides notification to approximately 210 members of the public within 5 miles of Palo Verde. Siren #25 provides notification to approximately 302 members of the public within 5 miles of Palo Verde. Siren #23 provides notification to approximately 498 members of the public within 5 miles of Palo Verde. Siren #22 provides notification to approximately 855 members of the public within 5 miles of Palo Verde. Siren #18 provides notification to approximately 396 members of the public within 5 miles of Palo Verde Siren #17 provides notification to approximately 1106 members of the public within 5 miles of Palo Verde. Siren #36 provides notification to approximately 301 members of the public within 5 miles of Palo Verde. Siren #15 provides notification to approximately 940 members of the public within 5 to 10 miles of Palo Verde. Each of these are considered by Palo Verde to be a 'large segment of the population.' The Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles, during an actual event, with loud speakers to alert persons within the affected area when sirens are inoperable. There are no events in progress that require siren operation. A follow-up call will be placed when the affected sirens are returned to service. The NRC Resident Inspector has been notified of the siren maintenance and this ENS call. These sirens are utility owned.
The following information was received as an update to this report: This is an update of ENS call # 44606. At this time, maintenance on the Palo Verde public prompt notification for sirens identified in ENS #44606, has been completed, siren testing was successful and the sirens are operable and in service at this time. The NRC Resident Inspector has been notified of the siren maintenance and this ENS call. Notified R4DO (Spitzberg). | ||
| ENS 44401 | 8 August 2008 22:20:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification to Maricopa County Environmental Services | Arizona Public Service Co. made an offsite notification to Maricopa County Environmental Services at 1520 MST on 8/8/08 to report a loss of power to the Palo Verde Nuclear Generating Station drinking water supply pumps. The pumps were out of service on 8/8/08 between the hours of 0532 and 0620 MST. Full service has been restored. The licensee notified the NRC Resident Inspector. | ||
| ENS 43876 | 31 December 2007 15:40:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Death of an Employee Outside the Protected Area | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. At approximately 06:40 MST on December 31, 2007, at the water reclamation facility for the Palo Verde Nuclear Generating Station, an employee died. The death was not related to activities impacting or related to the safety of the public or other onsite personnel. Specifically, an individual collapsed and was promptly examined by a Palo Verde Emergency Medical Technician (EMT). An air evacuation was ordered however, prior to air evacuation the individual expired. The death does not appear to be work-related nor the result of an accident. The individual was outside of the Radiological Controlled Area and no radioactive material or contamination was involved. Palo Verde has not observed any heightened public or media concern as a result of the death. Since the death is apparently unrelated to Palo Verde's industrial or radiological health and safety, no news release is planned. The individual's name has not yet been released, pending notification of next-of-kin. The Arizona Division of Occupational Safety and Health was notified of the death at 0840 MST. The Maricopa County Sheriff's Office is conducting a routine investigation into the death." The licensee notified the NRC Resident Inspector. | ||
| ENS 43824 | 4 December 2007 14:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness 10 CFR 50.72(b)(3)(xii), Transport of a Contaminated Person Offsite | Offsite Notification Due to Potential Loss of Three Sirens | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On December 04, 2007 at approximately 07:00 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department discovered sirens 17, 18 and 23 out of service. Siren #23 was restored to service at 09:34 and siren 18 was restored to service at 10:32. Siren 17 remains out of service and is estimated to impact approximately 206 members of population in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles. This call is being placed due to the relatively large segment of the population affected (10 CFR 50.72(b)(3)(xiii)). During an event, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected areas when sirens are inoperable. In order to activate this contingency, Maricopa County Department of Emergency Management was notified of the failed siren at 12:58 (10 CFR 50.72(b)(2)(xi)). There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren 17 being out of service and this ENS call. The utility received a pulse check report at 0700 this morning which indicated that three sirens failed the initial pulse check. After the second pulse check, two of the three sirens responded correctly. However, the third siren (No. 17) remained OSS, and the licensee has dispatched a crew to repair it. | ||
| ENS 43764 | 2 November 2007 14:44:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Suspicious Explosive Device Discovered in Vehicle at Oca Access Checkpoint | On November 2, 2007 at 0744 (MST), Palo Verde Nuclear Generating Station Units 1, 2 and 3 declared a Notification of an Unusual Event as specified in the Emergency Plan. The basis for the Emergency Class declaration was detection of a credible threat: an explosive device was detected during a vehicle search at the site access check point. The site has entered its Deliberate Acts procedure. The device was discovered in a contract employee's vehicle at 0525 MST. It was confirmed to be an explosive device at 0730 MST by the Maricopa County Sheriff's Office (MCSO). The explosive device was removed from the site by MCSO and Federal Bureau of Investigation (FBI) at 0852. The individual driving the vehicle has been detained by MCSO. No other individuals were in the vehicle at the time. Palo Verde Unit 1 is in Mode 2 at approximately 2% power. Unit 2 is in Mode 1 at 100% power. Unit 3 is defueled undergoing steam generator replacement. No reactor protection system or engineered safety feature system actuations have occurred and none are required. No major structures, systems, or components are inoperable impacting the continued safe operation of the units. Plans are to continue Mode 2 operations in Unit 1 and Mode 1 full power operation in Unit 2. Further investigation is ongoing in cooperation with MCSO and the FBI. Security is conducting searches of the site. No additional concerns have been identified at this time. The security event has not resulted in any challenges to the fission product barrier or result in any releases of radioactive materials. There were no adverse safety consequences or implications as a result of the security event declaration. A news release was made at 11:10 a.m. The licensee notified the NRC Resident Inspector.
At 1447 MST site security posture has changed from Code Red to Code Yellow Heightened Awareness, and at 1504 MST licensee exited the Unusual Event,. The licensee has notified the NRC Resident Inspector, state and local agencies, and will be issuing a press release this evening. Notifications were given to the following: R4 (Art Howell), R4DO(Powers), NRR EO (Bateman), IRD Manager (Blount), ILTAB (Sandler), DHS (York), FEMA (Dunker), DOE (Wyatt), FBI-SIOC (Curry), HHS (White), USDA (Phillip).
The licensee downgraded the security posture at the site from Code Yellow Heightened Awareness to Code Yellow. The licensee notified the NRC Resident Inspector. Notified R4DO (Powers) and ILTAB (Sandler).
Arizona Public Service Company (APS) is retracting security-related Event Notification #43764 and notification of unusual event (NUE) reported on November 2, 2007. Based upon investigations performed by the Federal Bureau of Investigation (FBI), Maricopa County Sheriff's Office (MCSO) and Palo Verde Security department, APS has determined that there was no explicit nor credible threatened action as described in 10 CFR 73.71, Appendix G, Paragraph I. These investigations revealed that the previously reported explosive device was placed in the owner's truck bed without his knowledge. Therefore, there is no reason to believe that a person has committed or caused, or attempted to commit or cause, or has made a credible threat to commit or cause: theft or unlawful diversion of special nuclear material; or significant physical damage to a power reactor; or interruption of normal operation of a licensed nuclear power reactor. The licensee notified the NRC Resident Inspector. R4DO (Farnholtz) has been notified and an e-mail sent to ILTAB and the 73.71 group. | Steam Generator Reactor Protection System | |
| ENS 42701 | 12 July 2006 14:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | One Siren in Ep Zone Is Out of Service | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On July 12, 2006 at approximately 07:30 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department reported siren (#23) out of service. Siren #23 is estimated to impact approximately 119 members of population in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles. This call is being placed due to the relatively large segment of the population affected. During an event, the Palo Verde Emergency Plan has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren 23 being out of service and this ENS call. The total population within the 5 mile EPZ is 2120. | ||
| ENS 42381 | 2 March 2006 21:30:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS. This is a report of a situation, related to the protection of the environment, for which a notification to another government agency has been or will be made, as described in 10CFR50.72(b)(2)(xi). Specifically, the Palo Verde Nuclear Generating Station (PVNGS) notified the Arizona Department of Environmental Quality (ADEQ) of the possibility of a discharge of non-hazardous material that has the potential to cause groundwater limits to be exceeded At Palo Verde Unit 3, water was observed in a concrete pipe vault that was abutted against soil. The source of the water appeared to becoming from seals around the pipes and originating from the ground behind the pipe chase. The area behind the pipe chase contains a series of pipes buried in a layer of compacted soil. In order to characterize the water and identify its source, a pothole, approximately 13 feet deep and reinforced with a perforated drain pipe was dug in the radiological controlled area yard so that a sample of the water could be obtained. Initial results from the unit laboratory indicated the presence of tritium. A confirmatory sample was collected and analyzed by the State certified laboratory at Palo Verde that confirmed the presence of tritium at a concentration of approximately 7.14 x 10 -5 microCurie per milliliter. The Aquifer Protection Permit Aquifer Quality Limit for tritium is 2.00 x 10 -5 microCurie per milliliter. At this time we are working to identify the source. We currently have no evidence that the water has contaminated any aquifer but are continuing with our investigation. Palo Verde's ground-water monitoring program - in place since the unit operations began - has validated that no tritium has been present in any wells or aquifers in any quarterly samples. PVNGS has just finished collecting its quarterly monitoring samples. Analyzed samples have no indication of tritium. The remaining samples will be completed next week. No Technical Specification effluent limits have been exceeded. No Offsite Dose Calculation Manual (ODCM) effluent limits have been exceeded. No federal effluent limits have been exceeded. Palo Verde has not identified any health or safety risk to the public or onsite personnel. No source of leakage or release path has been identified, therefore no release rate or total quantity released has been quantified. Unit 3 is operating at approximately 100% rated thermal power at normal operating temperature and pressure. This information is also being reported to the Arizona Radiation Regulatory Agency. The licensee notified the NRC Resident Inspector. | ||
| ENS 42101 | 31 October 2005 19:02:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Media Interest | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On October 31, 2005, at approximately 12:02 PM Mountain Standard Time (MST) the Palo Verde Nuclear Generating Station was informed of a request to conduct a media interview with a clearinghouse that provides newsworthy input to local media regarding an emergency preparedness exercise to commence tomorrow. No press release is planned by Palo Verde, but the interview is indication of media interest. The State of Arizona and Maricopa County will be performing an ingestion pathway emergency preparedness exercise on November 1, 2005 through November 3, 2005. The exercise will be evaluated by the Federal Emergency Management Agency (FEMA). Although this exercise will involve significant participation by State and County agencies, Palo Verde participation is expected to be limited to a small control cell of personnel to simulate communication with the State and County. There has been some media interest. There have been no official press releases posted by Maricopa County or the State of Arizona, although the Governor's calendar for November 1, 2005 indicates that the Honorable Janet Napolitano will participate. Resident NRC inspectors are not expected to participate in this exercise, but Palo Verde understands that two NRC Region IV personnel (Messrs. T. Andrews and W. Maier) are expected to support FEMA evaluation of the exercise. Palo Verde Unit 1 is in a refueling outage with all fuel assemblies offloaded to the spent fuel pool. Units 2 and 3 are operating in Mode 1 at approximately 100% power, at normal operating temperature and pressure. The licensee notified the NRC Resident Inspector. | ||
| ENS 41960 | 29 August 2005 17:30:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Off Site Notifications Due to Loss of Inoperable Emergency Evacuation Siren | On August 29, 2005 at approximately 10:30 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department identified an inoperable single siren (#18). The siren was vandalized by stealing the internal battery. The affected siren is estimated to impact approximately 131 members of population in the emergency planning zone (EPZ) within 5 miles. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area's) when sirens are inoperable. Maricopa County and State agencies have been informed to implement the MCSO notification if a need arises. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified | ||
| ENS 41941 | 23 August 2005 20:49:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Two Emergency Sirens Inoperable | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On August 23, 2005 at approximately 13:49 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department identified a siren (#42) inoperable due to a failed battery charger. At approximately 14:00 a faxed notice was found indicating siren #15 had failed its response check. The fax was sent approximately at 07:00 but was not noticed till later since out of service siren notifications are generally made via phone or e-mail. Upon investigation, siren #15 was found inoperable due to a circuit board failure. Siren #15 is estimated to impact approximately 144 members of population in the emergency planning zone (EPZ) within 5 miles, and siren #42 is estimated to impact 496 members of the population in the EPZ, beyond 5 miles but within 10 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles and 10% of the population beyond 5 miles but within 10 miles. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren failure and this ENS call. | ||
| ENS 41912 | 11 August 2005 15:45:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | One Emergency Preparedness Siren Out of Service | On August 11, 2005 at approximately 08:45 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department identified an inoperable single siren (#15). While reviewing the siren monitoring computer log, an Information Services Technician received a 'no response' signal on siren #15. Upon investigation, siren #15 was found inoperable. The siren was vandalized by destroying the siren controller case and stealing the internal battery. The affected siren is estimated to impact approximately 496 members of population in the emergency planning zone (EPZ) beyond 5 miles but within 10 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 10% of the population beyond 5 miles but within 10 miles. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. The County was informed at 09:05 MST to implement the MCSO notification if a need arises. There are no events in progress that require siren operation. The licensee notified the NRC Resident Inspector. | ||
| ENS 41874 | 26 July 2005 23:35:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Inoperable Single Emergency Siren | On July 26, 2005 at approximately 09:07 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Department was notified of an inoperable single siren (#42). While reviewing the siren monitoring computer log, an Information Services Technician received a no response signal on siren #42. Upon investigation, siren #42 was found inoperable. The siren was vandalized by destroying the battery case and stealing the internal battery. The affected siren is estimated to impact approximately 144 members of population (6.8%) in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles (or 10% within 5 to 10 miles) for greater than 1 hour. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. The County was informed at 09:38 MST to implement the MCSO notification if a need arises. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren failure and this ENS call. | ||
| ENS 41810 | 29 June 2005 11:43:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Evacuation Siren Inoperable | The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On June 29, 2005 at approximately 08:55 Mountain Standard Time (MST), the Palo Verde Emergency Preparedness Program Manager was notified of an inoperable single siren #36. An alarm indicates that the inoperability started at 04:43 AM MST. The siren was vandalized by destroying the battery case and stealing the internal battery. The affected siren is estimated to impact approximately 215 members of population (10.1 %) in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles (or 10% within 5 to 10 miles) for greater than 1 hour. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriffs Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. The County was informed at 09:25 AM MST to implement the MCSO notification if a need arises. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren failure and this ENS call. | ||
| ENS 41497 | 16 March 2005 01:51:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notifications Due to Caustic Spill | The following information was provided by the licensee via facsimile (licensee text in quotes): The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On March 15, 2005 at approximately 18:51 Mountain Standard Time (MST), the Palo Verde Nuclear Generating Station informed another government agency, the EPA/DOT National Response Center, of a caustic spill, related to the protection of the environment. Notification was also made to the Arizona Department of Environmental Quality and the Arizona Department of Public Safety (State Police). No news release is planned or expected. A commercial tanker truck was transferring caustic sodium hydroxide at Unit 1 when a drip was observed from the transfer hose at approximately 16:54 MST. The spill was limited to approximately one quart outside of the spill containment berm. The evolution was terminated and the tanker truck was driven out of the Protected Area. A drip trail was later discovered at approximately 18:00 along the path of the truck out of the Protected Area, including a puddle of approximately 3 gallons in the sally port (access point). The truck was returning to Phoenix, AZ. The spill quantity on-site is not estimated to have approached a reportable quantity (1,000 pounds), but due to the evidence that the truck was leaking while in transit to Phoenix, the Palo Verde Hazardous Materials Emergency Coordinator conservatively elected to make the government notifications. Additionally, Palo Verde notified the trucking company which ultimately located the truck upon its return to the company yard. No leak existed at that time, suggesting the leakage was limited to the caustic that remained in the truck's discharge pipe after the transfer was stopped. There was no impact to control room habitability and no safety systems, including essential ventilation, were actuated or required. The spill did not hamper site personnel in the performance of duties necessary for the safe operation of the nuclear power plant. The NRC Resident inspector was notified of the chemical spill and this ENS notification. | ||
| ENS 41486 | 13 March 2005 01:45:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Operability of One Emergency Evacuation Siren | The following was provided by the licensee: The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On March 12, 2005 at approximately 18:45 Mountain Standard Time, the Palo Verde Emergency Preparedness Program Manager was notified of an inoperable single siren #36. Palo Verde has had 4 other sirens vandalized by breaking locks and stealing the internal battery since approximately February 25, 2005. The specific cause of this siren being inoperable has not been determined. Based on evidence from previous testing, this loss of siren #36 has been established to have occurred sometime between 22:00, Friday, 03/11/2005 and 03:00, Saturday, 03/12/2005. The affected siren is estimated to impact approximately 82 members of population (5.1 %) in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles (or 10% within 5 to 10 miles) for greater than 1 hour. This call is being placed due to the relatively large segment of the population affected and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. Palo Verde has also been informed that Siren #42, previously inoperable due to the same vandalism and reported in EN #41451 on February 28, 2005, has been returned to service. There are no events in progress that require siren operation. There was not anything unusual or not understood concerning this event and all systems functioned as required. The NRC Resident Inspector has been notified of the siren failure and this ENS call. The licensee will inspect the siren on Sunday or Monday to determine if vandalism is involved. | ||
| ENS 41466 | 7 March 2005 15:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Two Emergency Sirens Inoperable | The following information was received from the licensee via facsimile (licensee text in quotes): The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On March 7, 2005 at approximately 08:10 Mountain Standard Time, the Palo Verde Emergency Preparedness Program Manager was notified of vandalism to two sirens, #18 and #23, that resulted in the sirens being inoperable. The affected sirens are estimated to impact approximately 465 (total) members of population (approximately 29%) in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles (or 10% within 5 to 10 miles) for greater than 1 hour. This call is being placed due to the relatively large segment of the population affected, and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren failure and this ENS call. The vandals cut the battery cables and removed the batteries. The theft has been reported to the MCSO. | ||
| ENS 41451 | 28 February 2005 21:57:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Major Loss of Siren Coverage within the Emergency Planning Zone | The following information was provided by the licensee via facsimile (licensee text in quotes): The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73. On February 28, 2005 at approximately 14:57 Mountain Standard Time, the Palo Verde Emergency Preparedness Program Manager was notified of vandalism to a single siren (#42) that resulted in the siren being inoperable. Based on evidence from previous testing, the vandalism has been established to have occurred sometime between 15:00, Friday, 02/25/2005 and 03:00, Saturday, 02/26/2005. The affected siren is estimated to impact approximately 116 members of the population (7.3%) in the emergency planning zone (EPZ) within 5 miles. Palo Verde's reporting criterion is a loss of capability to inform greater than 5% of the population within 5 miles (or 10% within 5 to 10 miles) for greater than 1 hour. This call is being placed due to the relatively large segment of the population affected, and the uncertainty of the length of time that will be needed to restore the siren to operable condition. The Palo Verde Emergency Plan (section 6.6.2.1) has a contingency for dispatching Maricopa County Sheriff's Office (MCSO) vehicles with loud speakers to alert persons within the affected area(s) when sirens are inoperable. There are no events in progress that require siren operation. The NRC Resident Inspector has been notified of the siren failure and this ENS call. | ||
| ENS 41268 | 17 December 2004 17:53:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notifications Made Due to Spill of Approximately 1400 Pounds of Sulfuric Acid | On 12/17/2004 at approximately 10:53 MST, Palo Verde Nuclear Generating Station (PVNGS) notified the Department of Transportation/US. Coast Guard National Response Center of a sulfuric acid spill to the ground at the Water Reclamation Facility. The source of cooling water for PVNGS is treated sewage effluent. The effluent is conveyed to the site through approximately 35 miles of pipeline, and treated in the onsite water reclamation facility to meet plant water quality requirements. The acid spill has no impact to the radiological health and safety of the workers or the public. The spill is estimated at 1400 pounds. The reportable quantity is 1000 pounds. The sulfuric acid is classified as a CERCLA Hazardous Substance and EPCRA Extremely Hazardous Substance. The release has been isolated and the apparent cause is a leak in an underground section of pipe. There were no injuries and no known or anticipated acute or chronic health risks. The National Response Center report number is 744571. The Arizona Department of Environmental Quality was also informed at 10:51 MST. There was no impact to the three generating units from the spill at the Water Reclamation Facility which is located at a separate part of the Owner Controller Area. All 3 PVNGS Units are operating at approximately 100% in Mode 1. The NRC Resident has been notified of the event and this notification. | ||
| ENS 40814 | 14 June 2004 14:44:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Alert Declared - Reactor Trip Due to Loss of Off Site Power | On June 14, 2004, at approximately 07:44 Mountain Standard Time (MST) all three units at the Palo Verde Nuclear Generating Station experienced automatic reactor trips coincident with a grid disturbance and loss of offsite power in the Palo Verde Switchyard. Unit 2 declared an ALERT Emergency Plan classification at approximately 07:54 due to a loss of AC power to essential buses reduced to a single power source for greater than 15 minutes such that any additional single failure would result in a station blackout. Subsequently, at 09:51 Unit 2 downgraded the Emergency Plan classification to a NOTIFICATION OF UNUSUAL EVENT when AC power was restored from a single essential bus to both essential buses. Units 1 and 3 declared a NOTIFICATION OF UNUSUAL EVENT at 07:53 MST due to a loss of offsite power to essential buses for greater than 15 minutes. The NOTIFICATION OF UNUSUAL EVENT was terminated for all 3 units at 12:07 MST. Unit 1 and 2 manually initiated a Main Steam Isolation System ESF actuation by procedure. Unit 3 received an automatic Main Steam Isolation System ESF actuation. Due to the loss of offsite power, the Emergency Plan Technical Support Center (TSC) was unavailable. The Unit 2 Satellite TSC was to be staffed by the Emergency Response Organization in response to the loss of assessment capability. Power to the TSC has since been restored. The Emergency Plan ALERT declaration includes staffing of the Joint Emergency New Center to address expected media interest. All three units were at normal operating temperature and pressure prior to the trip. All CEAs inserted fully into the reactor cores. All Emergency Diesel Generators (EDGs) (2 per unit) associated with each of the 3 units started as expected in response to the loss of offsite power to their safety buses. Unit 2's train "A" EDG started, but did not indicate volts or amps and was manually shutdown. The offsite power grid had several perturbations for approximately one hour following the event but has been stable since. LCO 3.8.1, AC Sources - Operating, was entered in each unit as a result of this event. Heat removal is to atmosphere via atmospheric dump valves in natural circulation. Main steam safety valves may have lifted for a brief time. Restoration of forced reactor coolant circulation is pending assurance that the offsite power grid can reliably support the load. No major equipment was inoperable prior to the event that contributed to the event. All 3 units are stable at normal operating temperature and pressure in Mode 3. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant NRC Resident Inspector was notified. FBI Jeff Muller and Mr. Rosales (Mexican National Commission of Nuclear Safety and Safeguards (CNSNS)) were notified.
Notified Reg 4 RDO (Graves), NRR (Bateman), DHS (Lee), FEMA (Canupp), DOE (Sal Moroni), EPA (Stalcup), EPA (Crews), HSS (Davidson), and Mexico (Rosales) NOTE: See events 40815, 40816 and 40818 | Emergency Diesel Generator Main Steam Safety Valve Main Steam |