Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 42487 | 10 April 2006 15:39:00 | 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 April 10. 2006, at approximately 12:33 hours Mountain Standard Time (MST), Palo Verde Nuclear Generating Station (PVNGS) Unit 2 commenced a reactor shutdown required by Technical Specification (TS) 3.7.5 Condition C. Limiting Condition for Operability (LCO) 3.7.5 requires three AFW trains to be Operable. Condition A of this LCO provides allowance for one steam supply to the turbine driven AFW to be inoperable for a 7 day period. If the inoperable SGAUV138A valve is not restored to an operable condition within 7 days, Unit 2 will be required to shutdown to Mode 3 in 6 hours and to Mode 4 in 12 hours, starting at 10:41 MST on April 10, 2006. 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 and is present in the control room. |
| ENS 47688 | 23 February 2012 00:45:00 | 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 49600 | 2 December 2013 23:26:00 | 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, 2013, at approximately 1758 Mountain Standard Time (MST), the Palo Verde Nuclear Generating Station (PVNGS) Unit 2 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 2 was operating normally at 100% power. Plant operators entered the emergency operations procedures and diagnosed an uncomplicated reactor trip but noted the 1A reactor coolant pump (RCP) was not running. All CEAs fully inserted into the core. Following the reactor trip, indications on the train A logarithmic (log) power nuclear instrument initially responded normally but then did not trend as expected. All other nuclear instruments responded normally and the train A log power channel was declared inoperable and technical specification limiting conditions for operation 3.3.10 and 3.3.11 were entered. No emergency classification was required per the PVNGS Emergency Plan. The Unit 2 safety related electrical busses remained energized from normal offsite power during the event. Due to planned maintenance on one switchyard breaker, the Ruud offsite power line was disconnected from the PVNGS switchyard when the Unit 2 main generator output breakers opened. There was no impact to the required circuits between the offsite transmission network and the onsite Class 1E Electrical Power Distribution System; the offsite power grid is stable. No major equipment was inoperable prior to the event that contributed to the event or complicated operator response. Unit 2 is currently stable in Mode 3 with the reactor coolant system at normal operating temperature and pressure. Preliminary information indicates the reactor trip resulted from an electrical protection trip of the power supply circuit breaker for the 1A RCP. 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 2 reactor trip. There was no impact on either Unit 1 or Unit 3. |
| ENS 50984 | 15 April 2015 02:07:00 | 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. |