Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 54916 | 27 September 2020 05:08:00 | At 0203 (CDT) on September 27, 2020 the plant was in Mode 1 at 98 percent power when a turbine trip/reactor trip (from a generator trip signal) occurred. All systems responded as expected. A Feedwater Isolation signal was received due to the reactor trip with RCS average temperature less than 564 degrees Fahrenheit. The Auxiliary Feedwater system started on a valid actuation signal to restore and maintain steam generator levels. The plant is being maintained stable in Mode 3 with no complications. The NRC Resident Inspector has been notified of the reactor trip. All control rods fully inserted from the reactor trip signal, and decay heat is being removed via the Auxiliary Feedwater and Steam Dump Systems. |
| ENS 50625 | 19 November 2014 03:39:00 | Following shift turnover from days to nights on 11/18/2014, it was discovered that all (4) of the Safety Injection (SI) Accumulator Outlet Isolation Valve breakers were unlocked and closed. At the time of discovery, 3 of the safety injection accumulator valves were open and 1 was closed for testing. At that time the plant was in MODE 3 at normal operating pressure and temperature. The plant had been performing RCS pressure isolation valve testing prior to shift turnover. The condition was discovered during testing of valves associated with the 'C' safety injection accumulator. After discovery of the condition, Operations directed that the 'A', 'B', and 'D' SI Accumulator Outlet Isolation Valve breakers be opened and locked. This action was completed by approximately 1930 (CST) on 11/18/2014. The NRC Resident Inspector was notified. The plant entered T.S. 3.0.3 for approximately 30 minutes while restoring the 'A', 'B' and 'D' accumulators to operable (breakers opened and locked with their associated outlet valves open). |
| ENS 48879 | 2 April 2013 20:30:00 | At 1707 CDT on 4/2/13 an arc flash occurred at the 'B' safeguards transformer (XMDV24) in the plant switchyard at Callaway. At the time of the flash, ground straps were being placed on the 'B' safeguards transformer which had been removed from service for maintenance. The event resulted in a loss of power to areas/buildings outside the power block. There was no impact to equipment and systems in the plant. Four workers were injured or affected by the flash. The extent of the electrical-related injuries has not been determined. However, based on reports from the scene, all of the workers were conscious and walked away from the scene. One person was transported by helicopter and two by ambulance to a local hospital. The fourth person experienced only a minor injury. The hazard has been isolated and investigation of the cause is in progress. Notifications of this event are planned to be made to OSHA and the Missouri Public Service Commission. The licensee notified the NRC Resident Inspector.
Ameren Missouri issued a press release about the event described above at approximately 1507 CDT on April 4, 2013. The NRC Resident Inspector was notified. Notified the R4DO (Kellar). |
| ENS 48245 | 28 August 2012 18:51:00 | At 1500 CDT on Tuesday, August 28, the Callaway Plant Technical Support Center (TSC) was declared non-functional due to ventilation recirculation flow rate outside of normal limits. Efforts are underway to restore TSC ventilation recirculation flow rate to normal. If TSC activation is necessary during the period of TSC non-functionality, the Emergency Coordinator will evaluate the suitability of the facility for the specific conditions of the event. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the unavailability of an emergency response facility. The NRC Resident Inspector has been notified |
| ENS 48112 | 17 July 2012 15:18:00 | At 1140 (EDT) on Tuesday, July 17, the Callaway Plant Technical Support Center (TSC) was declared non-functional due to a degraded charcoal filter in the building's filter absorber unit. At 1140 (EDT) on July 17, 2012, Callaway was notified of the test results for a charcoal test sample that was taken on July 5, 2012. The results did not meet surveillance procedure acceptance criteria. Efforts are underway to replace the charcoal in the unit. If an emergency were to be declared requiring activation of the TSC while it is non-functional, TSC emergency response personnel would report to their backup locations in accordance with Callaway Plant emergency planning procedures. This notification is being made in accordance with 10 CPR 50.72(b)(3)(xiii) due to the unavailability of an emergency response facility. The NRC Resident Inspector has been notified." The licensee indicated the TSC will be functional within 24 hours.
The TSC was restored to functional status at 2200 (CDT) on July 17, 2012. The licensee informed the NRC Resident Inspector. Notified R4DO (Walker). |
| ENS 47783 | 28 March 2012 18:26:00 | At 1500 on March 28, 2012, Callaway Plant personnel discovered that the installation of a modification on the two 'B' train containment cooler units had inadvertently introduced a potential failure mechanism to the 'B' train containment coolers. Specifically, with the containment cooling fans initially in fast-speed operation, combined with certain initial plant conditions, thermal overload tripping of the coolers could occur. In such an event, during some postulated accidents, slow-speed restart of the containment coolers by the Load Shedding and Emergency Load Sequencing system could be prevented. As a result, the 'B' train containment coolers could be rendered unavailable for a portion of a postulated accident. Thus, the safety function of the 'B' train containment cooling fans cannot be assured when this degraded equipment condition is present and the containment cooling fans are run in fast-speed operation. This condition existed for the 'B' train containment cooling units since they were restored to service from maintenance at 0400 on March 15, 2012. Upon identification of this condition, the 'B' train containment cooling fans were switched from fast-speed to slow-speed operation and restored to operable status at 1515. This action precludes this degraded equipment condition from adversely affecting containment cooling fan function during an accident. Concurrent with this condition, the opposite train of containment coolers was removed from service for scheduled maintenance at 0505 on March 27, 2012. As a result, from 0505 on March 27, 2012 until 1515 on March 28, 2012, the safety function of the containment cooling system could not be assured for certain postulated accident conditions. The NRC Resident Inspector has been notified. |
| ENS 45715 | 20 February 2010 03:49:00 | At 2145 CST on 2/19/2010, the Callaway Plant experienced a loss of switchyard bus 'A'. This resulted in a loss of off site power to 'B' train vital 4160 volt bus NB02. Technical specification LCO 3.8.1 was entered. The 'B' train emergency diesel generator started and the shutdown sequencer actuated for bus NB02. 'B' motor driven auxiliary feed water pump, 'B' centrifugal charging pump, and both 'A' and 'B' essential service water pumps started. The turbine driven auxiliary feed water pump actuated, and steam generator blowdown and sample isolation occurred. 'A' train offsite vital power and emergency diesel generator were available. The actuations that occurred were consistent with the loss of one vital AC train. All emergency systems responded as expected with the exception of steam generator blowdown valve BMHV0002 which was manually isolated when it failed to fully close. The loss of switchyard bus 'A' was due to a fault on the 'A' safeguards transformer. The faulted transformer has been isolated, and switchyard bus 'A' was reenergized at 0132 on 2/20/2010. The 'B' train vital 4160 volt bus NB02 was tied to offsite power at 0222 on 2/20/2010, and the 'B' emergency diesel generator was secured at 0233 on 2/20/2010. Technical specification LCO 3.8.1 was exited. Currently the plant is at 100% power. The licensee has notified the NRC Resident Inspector. |