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The query [[Category:ENS Notification]] [[Site::Braidwood]] [[Scram::+]] was answered by the SMWSQLStore3 in 0.5669 seconds.


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 Entered dateSiteRegionScramReactor typeEvent description
ENS 534434 June 2018 14:00:00BraidwoodNRC Region 3Manual ScramAt 0920 CDT, Braidwood Unit 1 reactor was manually tripped due to lowering steam generator water levels following a trip of the 1C main feedwater pump. The cause of the 1C main feedwater pump trip is unknown at this time and is under investigation. Both trains of Braidwood Unit 1 auxiliary feedwater started automatically following the reactor trip to maintain steam generator water levels. All systems responded as expected. Steam generator power operated relief valves lifted momentarily and reseated as designed in response to the secondary transient due to the reactor trip. The main steam dump valves are in service to the main condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. AC power is being provided by offsite power with the diesel generators in standby and all safety systems available. There is no impact to Unit 2. This report is being made per 10CFR50.72(b)(2)(iv)(B) for a RPS actuation, 4-hr. notification, and per 10CFR50.72(b)(3)(iv)(A) for an automatic actuation of the auxiliary feedwater system, 8-hr. notification. All rods inserted into the core during the trip. Concerning the relief valves momentarily lifting and reseating, there is no known primary-to-secondary leakage. The licensee has notified the NRC Resident Inspector.
ENS 5337130 April 2018 14:53:00BraidwoodNRC Region 3Automatic ScramWestinghouse PWR 4-LoopAt 1124 CDT, Braidwood Unit 1 experienced an automatic Reactor Trip. The cause of the Reactor Trip was a Turbine Trip with reactor power greater than P-8. The turbine trip was actuated as a result of a Turbine Motoring Generator Trip. The cause of the generator trip is unknown at this time and is under investigation. After the Reactor Trip occurred, the 1A Auxiliary Feedwater pump was manually started to provide feedwater flow to all four steam generators. The 1A Auxiliary Feedwater pump was subsequently secured and placed in standby when the Startup Feedwater pump was placed in service. Train A Main Control Room Ventilation Filtration system shifted to Makeup Mode due to a spurious actuation signal. No secondary relief valves lifted and no secondary steam was released as a result of the Reactor Trip. The Main Steam dump valves are in service to the Main Condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. AC power is being provided by Offsite Power with the Diesel Generators in standby and all safety systems available. There is no impact to Unit 2. This report is being made per 10 CFR 50.72(b)(2)(iv)(B) for a RPS actuation, 4-hr notification, and per 10 CFR 50.72(b)(3)(iv)(A) for a manual actuation of the Auxiliary Feedwater system, 8-hr notification. The licensee notified the NRC Resident Inspector and Illinois Emergency Management Agency.
ENS 4626220 September 2010 19:37:00BraidwoodNRC Region 3Automatic ScramWestinghouse PWR 4-LoopAt 1704 CDT, Braidwood Unit 1 experienced an automatic reactor trip. The reactor trip red first out was Over Temperature Delta Temperature (OTDT). At the time of the reactor trip, the Instrument Maintenance Department was performing a calibration of Power Range Channel N-43 and a calibration of the 1C S/G Narrow Range Level Channel 1L-0538. The cause of the trip is unknown at this time. After the reactor trip occurred, all four Steam Generators reached their Low-2 reactor trip setpoint and Pressurizer pressure reached its low pressure reactor trip setpoint which is an expected response on a trip from full power. Steam Generator levels and Pressurizer pressure have been restored. Both the 1A and 1B Auxiliary Feedwater pumps auto started on the Low-2 Steam Generator levels as expected. All control rods fully inserted into the core. Train B Main Control Room Filtration system shifted to makeup mode and the Train B Fuel Handling Building ventilation shifted to Emergency Mode due to a spurious actuation signal. No secondary relief valves lifted and no secondary steam (was) released as a result of the reactor trip. The Main Steam Dumps are in service to the Main Condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. This report is being made per 10CFR50.72(b)(2)(iv)(B) for RPS actuation, 4-hr. notification, and per 10CFR50.72(b)(3)(iv)(A) for automatic actuation of the Auxiliary Feedwater system, 8-hr. notification. AC power is being provided by offsite power with the Diesel Generators in standby and all safety systems available. There is no Unit 2 impact. The licensee notified the NRC Resident Inspector. The licensee also anticipates that there will be a press release issued regarding this event.
ENS 4617816 August 2010 06:23:00BraidwoodNRC Region 3Automatic ScramWestinghouse PWR 4-LoopBraidwood Unit 2 automatically tripped at 0206 (CST) due to a turbine generator trip due to generator lockout relay actuation. All systems responded as expected, with the auxiliary feed water pumps starting on Low-2 Steam Generator level. The Unit is stable in Mode 3, all primary systems are stable with the secondary heat sink being maintained via aux feed water and the steam dumps. Offsite power is supplying Unit 2, and both emergency diesel generators are available. Cause of generator lockout is under investigation. Braidwood Unit 1 automatically tripped at 0219 (CST) on a turbine trip caused by a loss of condenser vacuum. All systems responded as expected, with the auxiliary feed water pumps supplying steam generator levels. Secondary heat sink is steam generator PORVs. One steam generator safety valve is not fully seated. No steam generator tube leakage. Cause of the loss of vacuum is under investigation. For both Units all control rods fully inserted. There were no complications during the trip and all systems functioned as required. Offsite power remained available throughout the transient. The licensee notified the NRC resident inspector. Braidwood Unit 1's loss of condenser vacuum was caused by the loss of an electrical bus supplying the circ water pumps. At the time of this report, both plants were in a normal shutdown electrical lineup with the exception of the deenergized bus supplying power to the circ water pumps on Unit 1. The steam generator safety valve that has not fully seated was characterized as weeping a small amount of steam. The licensee is uncertain if the Unit 1 trip is related to the Unit 2 trip.
ENS 4501724 April 2009 15:15:00BraidwoodNRC Region 3Automatic ScramWestinghouse PWR 4-LoopAt 1141 CT, Braidwood Unit 2 experienced an automatic Reactor Trip. The Reactor Trip red first out annunciator was Over Temperature Delta Temperature (OTDT). At the time of the Reactor Trip the Instrument Maintenance Department was performing a scheduled calibration of a Pressurizer Pressure channel (2PT-456) which is in the B loop of reactor protection. During the calibration a spike occurred on the D loop of reactor protection. Specifically, the RCS (Reactor Coolant System) temperature for the D loop. This caused a Reactor Trip on a 2 of 4 coincidence. After the reactor trip occurred, all four steam generators reached their low-2 Reactor Trip setpoints and pressurizer pressure reached its low pressure Reactor Trip setpoint all of which is an expected response on a trip from full power. Steam Generator levels and Pressurizer pressure have been restored. Both the 2A and 2B Auxiliary Feedwater pumps auto started on the low-2 steam generator levels as expected. All control rods fully inserted into the core. No secondary relief valves lifted and no secondary steam released as a result of the Reactor Trip. Steam Generators are now being filled by the 2A Main Feedwater pump and the Auxiliary Feedwater pumps have been placed in standby. The main steam dumps are in service to the main condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. This report is being made per 10 CFR 50.72(b)(2)(iv)(B) for RPS actuation, 4 hour notification, and per 10 CFR 50.72(b)(3)(iv)(A) for automatic actuation of the Auxiliary Feedwater System, 8 hour notification. The electrical line up transferred to the normal shutdown configuration with the standby diesel generators and safety systems available. There is no Unit 1 impact. The licensee plans on issuing a press release and has notified the NRC Resident Inspector.
ENS 4474327 December 2008 18:36:00BraidwoodNRC Region 3Automatic ScramWestinghouse PWR 4-LoopAt 1418 on 12-27-08 Braidwood Unit 2 experienced an automatic Reactor Trip. The Reactor Trip red first out annunciator was Turb(ine) Trip above P8 Rx Trip. At the time of the trip the Unit Aux Transformer (UAT) 241-1 sudden pressure relay actuated causing a main generator trip which resulted in a main turbine trip which resulted in a Reactor Trip. Also at the same time as the Reactor Trip, the 2C Heater Drain Pump tripped on phase A over current. Damage was subsequently noted on the pump motor terminal box. No fire or smoke was observed at UAT 241-1 or the 2C Heater Drain Pump. After the Reactor Trip occurred, all four steam generators reached their low-2 Reactor Trip setpoints and the pressurizer reached its low pressure Reactor Trip setpoint all of which is an expected response on a trip from full power. Steam generator levels and pressurizer pressure have been restored. Both the 2A and the 2B Auxiliary Feedwater Pumps auto started on the low-2 steam generator levels as expected. All control rods fully inserted into the core. No secondary relief valves lifted and no secondary steam was released as a result of the Reactor Trip. Steam generators are now being filled by the Startup Feedwater Pump and the Auxiliary Feedwater Pumps have been placed in standby. The main steam dumps are in service to the main condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. This report is being made per 10CFR 50.72(b)(2)(iv)(B) for RPS actuation, 4 hr (notification), and per 10CFR 50.72(b)(3)(iv)(A) for automatic actuation of the Auxiliary Feedwater System, 8 hr (notification). The electrical line up transferred to the normal shutdown configuration with standby diesel generators and safety systems available. There was no impact on Unit 1. The licensee plans on issuing a press release and has notified the NRC Resident Inspector.
ENS 4359023 August 2007 20:14:00BraidwoodNRC Region 3Manual ScramWestinghouse PWR 4-LoopAt 1530 hours on 8/23/07, Braidwood Station Unit 2 was manually tripped due to lowering condenser vacuum. The lowering condenser vacuum resulted from the trip of two circulating water pumps. The cause of the two circulating water pump tripping is under investigation. All control rods inserted and there were no complications during the trip and all systems functions as required. Following the unit trip, the Auxiliary Feedwater System actuated as expected to maintain steam generator level. At the time of the unit trip, the Braidwood Station area was experiencing severe thunderstorms. Additionally, at 1604 hours, 19 of 70 emergency sirens for the Braidwood Station were declared inoperable due to a loss of power from storms in the area. As of 1704 hours, 19 sirens (greater than 25%) remain inoperable. This event is considered a major loss of offsite response capability and applies to both Braidwood Station Unit 1 and Unit 2. These events are is being reported under: (1) 10 CFR 50.72(b)(2)(iv)(B) as an event that results in the actuation of the reactor protection system (RPS) when the reactor is critical, (2) 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the PWR auxiliary feedwater system. (3) 10 CFR 50.72(b)(3)(xiii) as a major loss of offsite response capability. All safety buses remained powered by offsite power throughout this event. Emergency diesel generators are available if needed. No steam generator PORV's lifted as a result of the trip. Decay heat is being discharged to the condenser via the steam dumps. The licensee informed the NRC Resident Inspector.