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The query [[Category:ENS Notification]] [[Reactor type::Westinghouse PWR 4-Loop]] [[Scram::+]] was answered by the SMWSQLStore3 in 0.1947 seconds.


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 Entered dateSiteScramRegionReactor typeEvent description
ENS 533877 May 2018 06:42:00CookManual ScramNRC Region 3Westinghouse PWR 4-LoopOn May 7, 2018 at 0336 (EDT), DC Cook Unit 2 Reactor was manually tripped due to a high-high level experienced in the East Moisture Separator Drain Tank (MSDT) of the Moisture Separator Reheater (MSR). This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight (8) hour report. The NRC Resident Inspector has been notified. Unit 2 is being supplied by offsite power. All control rods fully inserted. All Aux Feedwater Pumps started properly. Decay heat is being removed via the Steam Generator Power Operated Relief Valves following Main Steam Stop Valve closure at 0431 due to a slow RCS (Reactor Coolant System) cooldown. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the Post Trip Review. No radioactive release is in progress as a result of this event.
ENS 533867 May 2018 05:23:00SalemManual ScramNRC Region 1Westinghouse PWR 4-LoopThis 4 and 8 hour notification is being made to report that Salem Unit 2 initiated a manual reactor trip and subsequent automatic Auxiliary Feedwater system actuation. The trip was initiated due to a 21 Reactor Coolant Pump reaching its procedural limit for motor winding temperature of 302F. Salem Unit 2 is currently stable in Mode 3. Reactor Coolant system pressure is 2235 PSIG and Reactor Coolant System temperature is 547 F with decay heat removal via the Main Steam Dump and Auxiliary Feedwater Systems. Unit 2 has no active shutdown technical specification action statements in effect. All control rods inserted on the reactor trip. All ECCS (emergency core cooling systems) and ESF (emergency safety function) systems functioned as expected. No safety related equipment or major secondary equipment was tagged for maintenance prior to this event. No personnel were injured during this event. The NRC Resident Inspector was notified. The Lower Alloways Creek Township will be notified.
ENS 5337130 April 2018 14:53:00BraidwoodAutomatic ScramNRC Region 3Westinghouse 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 5334819 April 2018 23:41:00Indian PointManual ScramNRC Region 1Westinghouse PWR 4-LoopWhile performing a turbine startup, a turbine control anomaly caused a steam generator level transient. The rise in steam generator level above the setpoint caused the turbine to automatically trip. The high steam generator level of 73 percent caused a feedwater isolation signal at 2107 EDT, which also tripped both Main Boiler Feed Pumps. The tripping of the Main Boiler Feed Pumps auto started the motor driven Aux Boiler Feed Pumps 21 and 23. The reactor was manually tripped at 2108 EDT in accordance with AOP-FW-1 Loss of Main Feedwater. All control rods inserted. Electrical power is being provided from offsite via the Station Aux Transformer. Decay heat removal is being provided via the Atmospheric Dump Valves. An investigation into the cause of the turbine control anomaly is underway. The NRC Resident Inspector has been notified. The event did not have an affect on Unit 3 and there is no primary to secondary leakage.
ENS 5332712 April 2018 12:14:00Watts BarAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopAt 0920 EDT on April 12, 2018, the Watts Bar Unit 2 reactor automatically tripped while operating at 100 percent power. All control and shutdown bank rods inserted properly in response to the automatic reactor trip. All safety systems including Auxiliary Feedwater actuated as designed. The plant is stable with decay heat removal through Auxiliary Feedwater and Steam Dump Systems. The cause of the automatic reactor trip is being investigated. The automatic actuation of the Reactor Protection System (RPS) is being reported as a four-hour report under 10 CFR 50.72 (b)(2)(iv)(B). The expected actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight-hour report under 10 CFR 50.72 (b)(3)(iv)(A). The NRC Senior Resident Inspector has been notified for this event. The plant is currently stable at normal operating temperature and pressure. The grid is stable and the plant is in its normal shutdown electrical lineup. Unit 1 was unaffected by the Unit 2 trip.
ENS 5321716 February 2018 13:58:00McGuireAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopAt 1014 (EST) hours on 2/16/18, with Unit 1 in Mode 1 at approximately 100 percent power, the reactor automatically tripped when the Reactor Trip Breakers opened during Train B Solid State Protection System (SSPS) testing. The trip was uncomplicated with all systems responding normally post-trip. Operations manually started the motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump (TDCAP) auto-started on low steam generator level. A Feedwater Isolation occurred as designed due to the Reactor Trip and Lo Tave condition. Operations stabilized the plant. Decay heat is being removed by the condenser. Unit 2 is not affected. Due to the Reactor Protection System actuation while critical, actuation of the TDCAP and motor driven auxiliary feedwater pumps along with the Feedwater Isolation, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5321616 February 2018 04:43:00Indian PointAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopOn February 16, 2018 at 02:01 EST Indian Point Unit 3 automatically tripped on a turbine trip due to a loss of main generator excitation. All control rods fully inserted and all plant equipment responded normally to the unit trip. This is reportable under 10 CFR 50.72(b)(2)(iv)(B). The auxiliary feedwater system actuated following the automatic trip as expected. This is reportable under 10 CFR 50.72(b)(3)(iv)(A). During the event offsite power remained available and stable. No primary or secondary reliefs lifted. The plant is stable, in Mode 3, at no load operating temperature and pressure. Decay heat removal is via the steam generators to the main condenser via the condenser steam dumps. No radiation was released. Indian Point Unit 2 was unaffected by this event and remains at 100 percent power. A post trip investigation is in progress. The licensee has notified the NRC Resident Inspector.
ENS 5311211 December 2017 11:06:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopWhile operating at 97% power, the Watts Bar Unit 2 reactor was manually tripped at 0857 EST on December 11, 2017 due to multiple dropped control rods. All control and shutdown bank rods inserted properly in response to the manual reactor trip. All safety systems including Auxiliary Feedwater actuated as designed. The plant is stable with decay heat removal through Auxiliary Feedwater and the Steam Dump System. The cause of the dropped rods is being investigated. The manual actuation of the Reactor Protection System (RPS) is being reported as a four hour report under 10 CFR 50.72 (b)(2)(iv)(B). The actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight hour report under 10 CFR 50.72 (b)(3)(iv)(A). The NRC Senior Resident Inspector has been notified for this event. No safety or relief valves lifted during this event.
ENS 5309126 November 2017 00:36:00Comanche PeakManual ScramNRC Region 4Westinghouse PWR 4-LoopAt time 2025 (CST) on 11/25/17, Unit 2 reactor was manually tripped due to a loss of all Main Feedwater. Operators observed both Main Feed Pumps tripped and SG (Steam Generator) levels decreasing, resulting in the direction for a manual reactor trip. The reactor trip actuated a turbine trip, both Motor Driven Auxiliary Feedwater Pumps started on the loss of both Main Feed Pumps, and Steam Generator Lo Lo levels started the Turbine Driven Auxiliary Feedwater Pump. All systems responded as expected. There was no work in progress at the time of the incident. Currently Unit 2 is being maintained in Hot Standby (Mode 3) in accordance with Integrated Plant Operating Procedure IP0-0078 and the Emergency Response Guideline Procedure Network has been exited. Decay Heat is being rejected to the Main Condenser via Steam Dump Valves. The licensee has notified the NRC Resident Inspector.
ENS 530523 November 2017 21:08:00Indian PointAutomatic ScramNRC Region 1Westinghouse PWR 4-Loop

On November 3rd, 2017 at 2022 EDT, the Indian Point Unit 3 Reactor Protection system automatically actuated at 100 percent power. Annunciator first out indication was from 33 SG (Steam Generator) Low Level. This automatic reactor trip is reportable to the NRC under 10 CFR 50.72(b)(2)(iv)(B). All control rods fully inserted on the reactor trip. All safety systems responded as expected. The Auxiliary Feedwater System actuated as expected. Offsite power and plant electrical lineups are normal. All plant equipment responded normally to the unit trip. No primary or secondary code safeties lifted during the trip. The Auxiliary Feedwater System actuated following the automatic trip as expected. This is reportable under 10 CFR 50.72(b)(3)(iv)(A). The Emergency Diesel Generators did not start as offsite power remained available and stable. The Unit remains on offsite power and all electrical loads are stable. Unit 3 is in Hot Standby at normal operating temperature and pressure with decay heat removal using auxiliary feedwater to the steam generators and normal heat removal through the condenser via the high pressure steam dumps. Unit 2 was unaffected and remains at 100 percent power. A post trip investigation is in progress. The licensee indicated that Radiation Monitor number 14 spiked twice during the transient, however, is currently not indicating any signs of radiation. The licensee will notify the NRC Resident Inspector and the NY Public Service Commission.

  • * * UPDATE AT 1523 EST ON 11/06/17 FROM RAMIREZ OVIDIO TO JEFF HERRERA * * *

The initial notification stated that Indian Point Unit 3 Reactor Tripped on 33 SG (Steam Generator) Low Level, this is incorrect. Indian Point Unit 3 Reactor Tripped on a Turbine Trip. The Turbine Trip was caused by a Generator Back-up Lockout Relay. The Turbine Trip was the 'first' annunciator first-out but was acknowledged instead of silenced during initial operator actions. The Turbine Trip first-out being acknowledged allowed a Low Steam Generator first-out to later annunciate. A Low Steam Generator Level is an expected condition post trip. This update does not change any actions taken by the operating team or required notifications under 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). A post trip investigation remains in progress. The licensee will notify the NRC Resident Inspector and the NY Public Commission. Notified the R1DO(Cook)

ENS 529452 September 2017 01:36:00Comanche PeakManual ScramNRC Region 4Westinghouse PWR 4-LoopAt time 2140 (CDT) on September 1, 2017, CPNPP (Comanche Peak Nuclear Power Plant) Unit 2 experienced two (2) dropped rods, one control, one shutdown. The reactor was then manually tripped. This event is being reported in accordance with 10CFR50.72(b)(2)(iv)(B) for reactor trip and 10CFR 50.72(b)(3)(iv)(A) for an actuation of auxiliary feedwater. Currently Unit 2 is being maintained in Hot Standby (Mode 3) in accordance with Integrated Plant Operating Procedure IP0-007B, Emergency Response Guideline Procedure Network has been exited. Decay Heat is being rejected to the Main Condenser via Steam Dump Valves (Turbine Bypass Valves). The NRC Resident Inspector has been notified. All rods inserted into the core during the trip. No relief or safety valves actuated during the plant transient. The electrical grid is stable and supplying plant loads. Unit 1 was not affected by the transient.
ENS 5287225 July 2017 11:07:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn July 25, 2017, at 0428 Eastern Daylight Time (EDT) Watts Bar Nuclear Plant (WBN) Unit 2 was in Mode 3, beginning a Reactor Startup. While in the initial phase of withdrawing the first of four Control Rod banks, the two associated group demand position indicators deviated greater than 2 steps from each other. In accordance with Technical Requirement 3.1.7, Position Indication System, Shutdown, with one or more group demand position indicators inoperable, the reactor trip breakers are to be opened immediately. Operations personnel opened the reactor trip breakers immediately by initiating a manual trip of the Reactor Protection System (RPS). The Auxiliary Feedwater system was in service and controlling Steam Generator water levels at the time of the event and did not receive any valid actuation signals. No other system actuations occurred as a result of this reactor trip and all systems operated as designed. The cause of the position indication system inoperability is currently under investigation. NRC Resident Inspector has been notified.
ENS 5282926 June 2017 18:39:00Indian PointManual ScramNRC Region 1Westinghouse PWR 4-LoopOn June 26, 2017, at 1531 (EDT), Indian Point Unit 2 inserted a manual reactor trip prior to Steam Generator levels reaching the automatic reactor trip setpoint. Steam Generator water level perturbation resulted from a loss of 22 Main Boiler Feed Pump. All Control Rods verified inserted. The Auxiliary Feedwater System started as designed and supplied feedwater to the Steam Generators. Heat removal is via the Main Condenser through the High Pressure Steam Dumps. Offsite power is being supplied through the normal 138kV feeder 95332. The cause of the 22 Main Boiler Feed Pump loss is currently under investigation. Entergy is issuing a press release/news release on this issue. Unit 2 is stable and in Mode 3. There was no impact on Unit 3. The licensee notified the State of New York and the NRC Resident Inspector.
ENS 527324 May 2017 19:53:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn May 4th, 2017, at 1709 EDT, Watts Bar Nuclear Plant Unit 1 reactor was manually tripped due to a failure of the #3 Reactor Coolant Pump normal feeder breaker to close during the planned power transfer to unit power following startup. Concurrent with the reactor trip, the Auxiliary Feedwater system actuated as designed. All Control and Shutdown rods fully inserted. All safety systems responded as designed. The unit is currently stable in Mode 3, with decay heat removal via Auxiliary Feedwater and Steam Generator Atmospheric Dump Valves. Unit 1 is in a normal shutdown electrical alignment. This reactor trip and system actuation is being reported under 10CFR 50.72(b)(3)(iv)(A) and 10CFR 50.72(b)(2)(iv)(B). There was no effect on WBN Unit 2. The NRC Senior Resident (Inspector) has been notified.
ENS 527252 May 2017 22:33:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn May 2nd, 2017, at 1945 EDT, Watts Bar Nuclear (WBN) Plant Unit 1 reactor was manually tripped due to a failure of the #3 Reactor Coolant Pump normal feeder breaker to close during the planned power transfer to unit power following startup. Concurrent with the reactor trip, the Auxiliary Feedwater system actuated as designed. All control and shutdown rods fully inserted. All safety systems responded as designed. The unit is currently stable in Mode 3, with decay heat removal via auxiliary feedwater and main steam dump systems. Unit 1 is in a normal shutdown electrical alignment. This reactor trip and system actuation is being reported under 10CFR 50.72(b)(3)(iv)(A) and 10CFR 50.72 (b)(2)(iv)(B). There was no effect on WBN Unit 2. The NRC Senior Resident (Inspector) has been notified.
ENS 5271829 April 2017 21:19:00SeabrookManual ScramNRC Region 1Westinghouse PWR 4-LoopAt 1844 (EDT) on 04/29/2017, while the unit was in a low power condition exiting from a refueling outage, the reactor was manually tripped following a P-14 signal (Steam Generator Hi-Hi Level) and a resulting feedwater isolation signal. All control rods were verified to be fully inserted. The cause of the ('B') steam generator high level is currently being investigated. Emergency feedwater actuated at 1845 due to a low-low water level in steam generator 'D'. Plant equipment response is being evaluated and the plant is stabilized in Mode 3 with decay heat removal through the steam dump system to the condensers. There was no release and the emergency feedwater system has been restored to standby. The 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. The licensee notified the NRC Resident Inspector.
ENS 5262520 March 2017 10:17:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn March 20, 2017 at 0813 EDT, Watts Bar Nuclear Plant (WBN) Unit 2 operations personnel manually tripped the plant from approximately 91 percent power based on lowering steam generator levels. Prior to the plant trip, the 2A Hotwell pump tripped at 0758 EDT and the 2C Condensate Booster Pump subsequently tripped at 0802 EDT. Operations personnel commenced to lower plant power after the 2A Hotwell pump trip in an attempt to maintain steam generator levels, but were unable to recover level and manually tripped the unit. All control rods fully inserted and all automatically actuated safety related equipment operated as designed. At 0905 EDT, operations personnel exited the emergency operating instructions after the plant was stabilized. The cause of the event is under investigation. This event is reportable to the NRC within four hours under 10 CFR 50.72(b)(2)(iv)(B) as a result of the actuation of the Reactor Protection System and in eight hours under 10 CFR 50.72(b)(3)(iv)(A) as a result of actuation of the Auxiliary Feedwater system. The licensee notified the NRC Resident Inspector.
ENS 525343 February 2017 18:56:00VogtleManual ScramNRC Region 2Westinghouse PWR 4-LoopAt 1545 EST on 2/3/17, Vogtle Unit 1 was manually tripped from 100% power when loop 1 Main Steam Isolation Valve (MSIV) started to fail closed. Non-Safety Related 4160V bus 1NA01 failed to transfer to alternate incoming power supply automatically and was successfully manually energized. All control rods fully inserted and AFW (Auxiliary Feedwater) and FWI (Feedwater Isolation) actuated as expected. Unit 1 is in Mode 3 and stable with decay heat being removed by AFW. The licensee informed the NRC Resident Inspector.
ENS 5246930 December 2016 16:37:00SequoyahManual ScramNRC Region 2Westinghouse PWR 4-LoopOn 12/30/16 at 1302 EST, Unit 1 began withdrawing control bank rods for an approach to criticality following a refueling outage. At 1305 EST, operators observed that control rod H-6 did not withdraw. Operators entered the applicable Abnormal Operating Procedure. Operators tripped the reactor as required by plant procedures and entered applicable Emergency Operating Procedures. The act of manually tripping the reactor generated a valid trip signal in the plant Reactor Protection System. Following the reactor trip, all safety related equipment operated as designed. Auxiliary feedwater was already supplying the Steam Generators; a Feedwater Isolation occurred due to plant conditions. Unit 1 is currently being maintained in Mode 3 at NOT/NOP, approximately 548 degrees F and 2235 psig, with auxiliary feedwater supplying the steam generators, and decay heat removal via the steam dumps. Method of decay heat removal is Steam Generators via the steam dumps. Current reactor coolant system conditions: Temperature at 548 degrees F and stable, pressure 2235 psig and stable. All control and shutdown banks are inserted. Electrical alignment is normal, supplied by offsite power. No impact to Unit 2, Unit 2 is in Mode 1 at 100 percent power. The licensee notified the NRC Resident Inspector.
ENS 5229512 October 2016 15:17:00ByronManual ScramNRC Region 3Westinghouse PWR 4-LoopAt 1338 CDT, a spurious electrical fault on a unit substation motor control center caused a spurious feedwater isolation and required a manual reactor trip on Unit 2 Byron Station due to lowering steam generator level. Auxiliary feedwater automatically actuated to supply feedwater flow and is maintaining steam generator level within procedurally required levels. The motor control center fault resulted in feedwater isolations on two of four steam generators. All rods inserted during the trip. Decay heat is being removed via the steam dumps to condenser. Plant response to the trip was uncomplicated. Unit 2 is in a normal shutdown electrical lineup with power available from offsite. The grid is stable. Byron Station Unit 1 is at 95% power and stable and was unaffected by the transient on Unit 2. The cause of the motor control center fault is under investigation. The licensee has notified the NRC Resident Inspector and will be issuing a press release concerning the manual reactor trip.
ENS 5221331 August 2016 18:12:00SalemAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopThis 4-hour and 8-hour notification is being made to report that Salem Unit 2 had an unplanned automatic reactor trip and automatic actuation of the auxiliary feedwater system. The trip occurred due to the loss of the 21 reactor coolant pump (RCP) resulting in a reactor trip on low reactor coolant flow. The 21 RCP remains unavailable. The cause of the loss of the 21 reactor coolant pump is unknown at this time. All control rods inserted on the reactor trip. All emergency core cooling systems and engineered safety feature systems functioned as expected. The auxiliary feed pumps started as expected. Salem Unit 2 is currently in Mode 3. Reactor coolant system pressure is at 2235 psig and temperature is 547 degrees Fahrenheit with decay heat removal via the main steam dumps and auxiliary feedwater systems. Unit 2 has no active technical specification action statements in effect requiring a lower mode of operation due to the transient. The 21 and 22 containment fan coil units (CFCU) were out of service for surveillance testing prior to the event. There was no major secondary equipment tagged for maintenance prior to the event. There were no personnel injuries as a result of this event. Normal offsite power is available to the site. There is no effect on Unit 1. The licensee notified the NRC Resident Inspector.
ENS 5219423 August 2016 15:30:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn August 23, 2016, at 1356 EDT, Watts Bar Nuclear Plant (WBN) Unit 2 reactor was manually tripped due to a loss of main feedwater. Concurrent with the reactor trip, the Auxiliary Feedwater system actuated as designed. All control and shutdown rods fully inserted. All safety systems responded as designed. The unit is currently stable in Mode 3, with decay heat removal via Auxiliary Feedwater and main steam dump systems. Unit 2 is in a normal shutdown electrical alignment. The cause is currently under investigation. This is being reported under 10CFR 50.72(b)(3)(iv)(A) and 10CFR 50.72(b)(2)(iv)(B). There was no effect on WBN Unit 1. The NRC Senior Resident Inspector has been notified.
ENS 520676 July 2016 13:16:00Indian PointAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopOn July 6, 2016 at 0938 EDT Indian Point Unit 2 experienced a trip from 100% steady state power during the performance of reactor protection testing. The cause of the trip is under investigation. All control rods fully inserted and all systems responded as expected. The auxiliary feedwater system actuated as expected on a low level in the steam generators which occurs as a result of a trip from full power. Auxiliary feedwater is maintaining steam generator levels and decay heat removal is via the steam generators to the main condenser. Offsite power and plant electrical line ups are normal with the exception of 13.8kV feeder 33332 which remains out of service during the replacement of breaker BT4-5. No primary or secondary code safety relief valves lifted. The reactor is in Mode 3 and stable. Indian Point Unit 3 was unaffected and remains at 100% steady state power. The NRC Resident Inspector has been notified. The licensee notified the New York Public Service Commission and the New York Independent System Operator. Indian Point indicated they have issued a press release regarding the event.
ENS 520656 July 2016 01:02:00CookManual ScramNRC Region 3Westinghouse PWR 4-LoopOn July 6, 2016, at 0038 (EDT), DC Cook Unit 2 Reactor was manually tripped and at 0050 (EDT) an Unusual Event (N-7 'Unanticipated Explosion') Emergency Declaration was made due to steam leak and associated damage to the turbine building. In accordance with Emergency Plan procedures, notifications of Berrien County and State of Michigan were completed. The licensee has notified the NRC Senior Resident Inspector. The Unusual Event was terminated at 0207 (EDT). This notification is being made in accordance with 10 CFR 50.72 (a)(1)(i) due to declaration of an emergency class. Original notification to NRC made at 0100 EDT via ENS. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation and 10 CFR 50.72(b)(2)(xi) Offsite Notification, as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight (8) hour report. The DC Cook NRC Resident Inspector has been notified. A press release is planned. Unit 2 is being supplied by offsite power. All control rods fully inserted. Decay heat is being removed via Steam Generator PORVs (Power Operated Relief Valve). Preliminary evaluation indicates all plant systems functioned normally following the reactor trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the Post Trip Review. No radioactive release is in progress as a result of this event. Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via email.
ENS 5204828 June 2016 06:58:00SalemAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopThis 4 and 8 hour notification is being made to report that Salem Unit 2 suffered an unplanned automatic reactor trip and subsequent automatic auxiliary feedwater system actuation. The trip was initiated due to a Main Turbine Trip above P-9 (49% power). The Main Turbine trip was caused by a Main Generator Protection signal. Salem unit 2 is currently stable in Mode 3. Reactor coolant system pressure is 2235 psig and Reactor Coolant System temperature is 547 F with decay heat removal via the main steam dump and auxiliary feedwater systems. Unit 2 has no active shutdown tech spec action statements in effect. All control rods (fully) inserted on the reactor trip. All ECCS (Emergency Core Cooling System) and ESF (Emergency Safety Features) systems functioned as expected. No safety related equipment or major secondary equipment was tagged for maintenance prior to this event. No personnel were injured during this event. The main generator protection signal was either a ground fault or a differential current trip. The plant is in its normal shutdown electrical lineup. No safeties or relief valves lifted during this event. Unit 1 is defueled and was not affected by this event. The licensee notified the NRC Resident Inspector and will notify the Lower Alloways Creek Township.
ENS 5195625 May 2016 04:54:00VogtleAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopAt 0206 EDT 5/25/16, Vogtle Unit 2 tripped from 100% when SG (Steam Generator) #1 Level began to lower for an unknown reason. Cause for level issue is under investigation. All control rods fully inserted and AFW (Auxiliary Feedwater) and FWI (Feedwater Isolation) actuated as expected. Unit 2 is in Mode 3 and stable with decay heat being removed by Aux Feedwater. Prior to the trip, I & C (Instrumentation & Calibration) was performing a loop #1 narrow range instrument calibration. Unit 2 is in a normal post trip electrical lineup with all source of offsite power available. The licensee informed the NRC Resident Inspector.
ENS 5192915 May 2016 07:08:00MillstoneManual ScramNRC Region 1Westinghouse PWR 4-Loop

At 0638 EDT on 5/15/2016, an Unusual Event (EAL GU.2) was declared on Millstone Unit 3 due to a Main Generator hydrogen gas leak into the Turbine Building. At 0645 EDT, operators manually tripped the reactor. All rods inserted. All systems functioned as expected following the reactor trip. Operators are currently venting the remaining hydrogen from the generator through the normal vent path. There is no safety related equipment out-of-service. The plant is in a normal post-trip electrical line-up. All Emergency Diesel Generators are available. The licensee notified the State of Connecticut and the NRC Resident Inspector. Notified DHS SWO, FEMA Ops Center, and DHS NICC Watch Officer. Notified via E-mail FEMA National Watch Center and NuclearSSA.

  • * * UPDATE FROM MIKE CICCONE TO HOWIE CROUCH AT 1044 EDT ON 5/15/16 * * *

At 0949 EDT, the licensee terminated the Unusual Event. At 0645 EDT on 5/15/16, a manual reactor trip was initiated at Millstone Unit 3 due to a hydrogen leak from the main generator. As expected, Auxiliary Feedwater System (AFW) initiated on the reactor trip. The trip was uncomplicated and the plant is currently in Mode 3 with a normal electric lineup and decay heat is being removed via steam dumps to the condenser. The cause of the hydrogen leakage is under investigation. This is reportable under 10 CFR 50.72(b)(2)(iv)(B) - RPS actuation while critical, and 10 CFR 50.72 (b)(3)(iv)(A) - valid specified system actuation. The licensee has notified Waterford Township, the State of Connecticut and the NRC Resident Inspector. Notified R1DO (Burritt), NRR ET (McDermott), NRR EO (Morris), IRD (Grant), DHS SWO, FEMA Ops Center, DHS NICC, FEMA National Watch Center (email) and NuclearSSA (email).

ENS 518971 May 2016 22:14:00South TexasAutomatic ScramNRC Region 4Westinghouse PWR 4-LoopAt 2021 (CDT) on 05/01/2016 Unit 1 automatically tripped due to a generator lockout. Relay 86/G1 actuated. The generator lockout resulted in a Unit 1 turbine trip and a reactor trip. Auxiliary Feedwater and Feedwater Isolation actuated as designed. All Control Rods fully inserted. No primary or secondary relief valves opened. There were no electrical problems. Normal operating temperature and pressure is (being maintained). There were no significant TS LCO's entered. This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected. Unit 1 is stable in Mode 3, with decay heat being removed via dump valves to the condenser. The cause of the generator lockout is under investigation. The licensee notified the NRC Resident Inspector.
ENS 5173414 February 2016 23:13:00SalemAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopThis 4-hour and 8-hour notification is being made to report that Salem Unit 2 had an unplanned automatic reactor trip. The trip occurred because the Unit 2 main generator tripped on generator protection with reactor power greater than P-9 (49%). The cause of the generator protection trip that resulted in the reactor trip is unknown at this time. A troubleshooting team is being assembled to determine the exact cause for the generator protection actuation. All control rods inserted on the reactor trip. All ECCS and ESF systems functioned as expected. The motor driven and steam driven auxiliary feed pumps started as expected on steam generator low level. Salem Unit 2 is currently in mode 3. Reactor Coolant System pressure is at 2235 psig and temperature is 547 degrees Fahrenheit with decay heat removal via the main steam dumps and auxiliary feedwater systems. Unit 2 has no active technical specification action statement in effect requiring a lower mode of operation. No safety related equipment or major secondary plant equipment was tagged for maintenance prior to the event. There were no personnel injuries as a result of this event. There was no impact on Salem Unit 1. The licensee informed the NRC Resident Inspector and will inform the Lower Alloways Creek Township (LAC).
ENS 517084 February 2016 13:33:00SalemAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopThis 4 and 8 hour notification is being made to report that Salem Unit 2 suffered an unplanned automatic reactor trip and subsequent automatic Auxiliary Feedwater system actuation. The trip was initiated due to a Main Turbine trip above P-9 (49% power). The Main Turbine trip was caused by a Main Generator Protection signal. Salem Unit 2 is currently stable in Mode 3. Reactor Coolant system pressure is 2235 PSIG and Reactor Coolant system temperature is 547 F with decay heat removal via the Main Steam Dump and Auxiliary Feedwater Systems. Unit 2 has no active shutdown tech spec action statements in effect. All control rods inserted on the reactor trip. All ECCS and ESF systems functioned as expected. No major secondary equipment was tagged for maintenance prior to this event. The 24 Service Water pump is tagged for scheduled preventive maintenance and did not affect post trip plant response. No personnel were injured during this event. The licensee has notified the NRC Resident Inspector and will notify the Lower Alloway Creek Township.
ENS 5168727 January 2016 01:44:00South TexasManual ScramNRC Region 4Westinghouse PWR 4-Loop

At 2325 (CST) on 01/26/2016, Unit 1 was manually tripped due to loss of Feedwater on 'C' S/G (Steam Generator). The loss of Feedwater was a result of a failure on 'C' S/G Main Feedwater Regulating Valve that caused the valve to travel closed with no Operator action. Auxiliary Feedwater and Feedwater Isolation actuated as designed. All Control and Shutdown Rods fully inserted. Intermediate Range Nl 36 (Nuclear Instrument) failed above P10 and, as a result, Source Range Nuclear Instruments were manually energized. No primary or secondary relief valves opened. There were no electrical problems. Normal operating temperature and pressure (NOT/NOP) is 567 degrees F and 2235 psig. There were no significant TS LCOs entered.

This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected. Decay heat removal is being controlled via Steam Dumps. Offsite power is in the normal electrical lineup. The NRC Resident Inspector has been notified.

ENS 5168225 January 2016 03:21:00MillstoneAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopAt 0147 EST on 1/25/16, the 'B' Reactor Coolant Pump (RCP) tripped offline. This caused a reactor trip on low coolant flow. As expected, the Aux Feedwater System (AFW) initiated on the reactor trip. The trip was uncomplicated and the plant is currently shutdown in Mode 3 with a normal electrical lineup and decay heat is being removed via steam dumps to the condenser. The cause of the 'B' RCP trip is under investigation. A containment entry is planned for dayshift on 1/25/16 to inspect and troubleshoot the 'B' RCP. The Licensee has notified the NRC Resident Inspector.
ENS 5161521 December 2015 18:06:00South TexasManual ScramNRC Region 4Westinghouse PWR 4-LoopAt 1519 (CST), the Main Turbine was tripped due to an Oscillating Governor Valve 2 (cause not known). At 1533, Unit 1 was manually tripped due to a feedwater isolation P-14 (caused by steam generator swell induced high steam generator level, resulting in) steam generator low level (after the isolation). Aux feedwater actuated as designed. All Control and Shutdown Rods fully inserted. Intermediate Range NI 36 failed above P-10 so SR-Nis (source range nuclear instruments) were manually energized. No primary relief valves lifted. All Steam Generator PORVs (power operated relief valves) opened. There were no electrical bus problems. Normal operating temperature and pressure (NOT/NOP) is 567F and 2235 psig. There were no significant TS LCOs (Technical Specification limiting conditions for operations) entered. This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected and continues to operate at 100% power. The licensee has notified the NRC Resident Inspector.
ENS 5160614 December 2015 19:49:00Indian PointAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopAt 1906 (EST) on 12/14/2015, Indian Point Unit 3 received a Main Generator Lockout trip signal, and the reactor automatically tripped. Site personnel reported seeing arcing on a 345kV output transmission line tower. At the time of the trip, there was moderate rain and fog in the area. The site fire brigade leader investigated the reports of arcing and found no evidence of fire; fire brigade response was not required. All automatic systems functioned as designed and all control rods inserted automatically. Auxiliary Feedwater Pumps started automatically due to expected low steam generator levels following a reactor trip from 100% power. Unit 3 is being maintained in Mode 3 with decay heat removal via steam dumps to the condenser. Offsite power remains available and in service from 138kV to the 480V safeguards buses. The cause of the Main Generator Lockout signal is being investigated. Unit 2 was not impacted and continues to operate at 100% power. The NRC Resident Inspector has been notified. After the trip, operators observed high vibrations on the 33 reactor coolant pump which eventually returned to normal range. The licensee will be notifying the New York Public Service Commission and their local Independent System Operator. A press release will be issued by the Communications Department.
ENS 515865 December 2015 18:48:00Indian PointManual ScramNRC Region 1Westinghouse PWR 4-LoopAt 1731 (EST) on December 5, 2015, Indian Point Unit 2 Control Room operators initiated a Manual Reactor Trip due to indications of multiple dropped Control Rods. The initiating event was a smoldering Motor Control Center (MCC) cubicle in the Turbine Building that supplies power to the Rod Control System. The unit is stable in Mode 3 with heat sink provided by Auxiliary Feedwater and decay heat removal is via the steam dumps to the condenser. Offsite Power remains in service. The smoldering MCC cubicle had power removed from it when 24 MCC breaker tripped on overcurrent. The affected cubicle has ceased smoldering and is being monitored by on-site Fire Brigade trained personnel. The trip of 24 MCC removed power to 22 Battery Charger, 22 DC Bus remained powered from the 22 Battery without interruption, and 22 Battery Charger was subsequently repowered. The cause of the smoldering MCC is being investigated and a post reactor trip evaluation is being conducted by the licensee. There was no impact on Unit 3, which continues to operate at 100% power. The licensee has notified the NRC Resident Inspector and appropriate State and Local authorities.
ENS 5155923 November 2015 11:52:00SequoyahManual ScramNRC Region 2Westinghouse PWR 4-LoopAt 0820 EST on 11/23/2015, Sequoyah Unit 1 was at 100% power when operators identified the Loop #3 Main Steam Isolation Valve (MSIV) came off its full open seat. This was evidenced by no OPEN indication on the main control board, dual indication on the post accident monitoring panel, and a change in both Tavg and steam pressure. Operators were dispatched locally to the MSIV and to the battery board room to investigate if a cause could be identified for the MSIV movement. The field investigation identified no issues. The operating crew manually tripped the reactor at 0844 EST due to an increasing Tavg-Tref mismatch. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the feedwater isolation signal. Unit 1 is currently being maintained in Mode 3 at normal operating temperature and pressure, approximately 547 degrees F and 2235 psig, with auxiliary feedwater supplying the steam generators and decay heat removal via the condenser steam dumps. There is no indication of any primary to secondary leakage. All control rods fully inserted on the reactor trip and remain inserted. The electrical alignment is normal with shutdown power supplied from off-site power. There is no operational impact to Unit 2 as it continues through the refueling outage with the core off-loaded. There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector. All control rods fully inserted during the reactor trip. The atmospheric steam dumps did operate during the transient and then shut. After the trip, the MSIV re-opened.
ENS 514443 October 2015 12:02:00Comanche PeakManual ScramNRC Region 4Westinghouse PWR 4-Loop

During the scheduled Unit 2 down power to start 2RF15, Steam Generator 3 Feed Control Valve failed to control in Automatic or Manual resulting in excessive feedwater flow. Control Room Operators manually tripped the reactor and aligned Auxiliary Feedwater. No automatic RPS or ESF actuations occurred. Plant conditions are stable. All control rods fully inserted on the trip and no safety or relief valves lifted. The plant is supplying water to the steam generators with auxiliary feedwater and removing decay heat through the main condenser. The unit is in its normal shutdown electrical lineup. There was no effect on unit-1. The licensee informed the NRC Resident Inspector.

  • * * UPDATE AT 1848 EDT ON 10/05/15 FROM JOHN RASMUSSEN TO JEFF HERRERA * * *

The licensee added 10 CFR 50.72(b)(3)(iv)(A) to the 10 CFR codes reporting section. No other text was modified. Notified the R4DO (Taylor).

ENS 5139214 September 2015 08:12:00SequoyahManual ScramNRC Region 2Westinghouse PWR 4-LoopAt 0426 EDT on 9/14/2015, Sequoyah Unit 1 was at 100% power when the Vital Instrument Power Board (VIPB) 1-II deenergized. A manual reactor trip was initiated in accordance with the Abnormal Operating Procedure for the loss of VIPB 1-II. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal. Unit 1 is currently being maintained in Mode 3 at NOT/NOP (Normal Operating Temperature/Normal Operating Pressure), approximately 547 degrees F and 2235 psig, with auxiliary feedwater supplying the steam generators and decay heat removal via the condenser steam dumps. Current Temperature and Pressure - Reactor Coolant System (RCS) temperature is 547 degrees F and stable and RCS pressure is 2235 psig and stable. There is no indication of any primary to secondary leakage. All rods fully inserted on the reactor trip and remain inserted. The electrical alignment is normal with shutdown power supplied from off-site power. There is no operational impact to Unit 2. Unit 2 continues to operate in Mode 1 at 100 (percent). There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector.
ENS 5130811 August 2015 05:19:00CallawayAutomatic ScramNRC Region 4Westinghouse PWR 4-LoopReactor trip caused by turbine trip. Turbine tripped immediately following the trip of one of four 345KV offsite lines. The reason for protective relaying not preventing the grid disturbance from tripping the turbine generator is not known at this time. All normal offsite and onsite power sources are available. Auxiliary Feedwater actuated as expected on low steam generator level following the trip from 100% power. All systems functioned as expected in response to the trip. The NRC Senior Resident Inspector has been notified. An electrical fault on a 345 kV line 2 miles from the site caused the bus to strip and reclose, which cleared the fault. All control rods fully inserted and the plant is in its normal shutdown electrical lineup.
ENS 512905 August 2015 18:51:00SalemAutomatic ScramNRC Region 1Westinghouse PWR 4-LoopThis 4-hour and 8-hour notification is being made to report that Salem Unit 2 had an unplanned automatic reactor trip. The trip occurred because the 2H 4kV infeed breaker tripped on over current protection which deenergized the 2H 4kV group bus resulting in a reactor trip on reactor coolant flow due to the loss of the 21 reactor coolant pump (RCP). The 21 RCP remains unavailable. The cause of the over current protection trip on the 2H 4kV infeed breaker is unknown at this time. All control rods inserted on the reactor trip. All ECCS (emergency core cooling systems) and ESF (engineered safety feature) systems functioned as expected. The auxiliary feed pumps started as expected. Salem Unit 2 is currently in Mode 3. Reactor coolant system pressure is at 2235 psig and temperature is 547 degrees Fahrenheit with decay heat removal via the main steam dumps and auxiliary feedwater systems. Unit 2 has no active technical specification action statements in effect requiring a lower mode of operation due to the transient. The 22 auxiliary building supply fan was tagged for maintenance prior to this event and has no adverse impact of the post trip plant response or stabilization. There was no major secondary equipment tagged for maintenance prior to the event. There were no personnel injuries as a result of this event. There is no physical evidence of damage to the 2H 4kV bus based on visual observations and thermography. Normal offsite power is available to the site. There is no effect on Unit 1. The licensee has notified the NRC Resident Inspector and will notify the Lower Alloways Creek Township Police Department.
ENS 5125924 July 2015 17:04:00SequoyahAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopAt 1351 EDT on 7/24/2015, Sequoyah Unit 1 reactor/turbine automatically tripped. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal. Unit 1 is currently being maintained in Mode 3 at NOT/NOP, approximately 548 F and 2235 psig, with auxiliary feedwater supplying the steam generators and decay heat removal via the condenser steam dumps. The immediate cause of the trip was an electrically-induced turbine trip. There was no associated work in progress related to this and all systems were normally aligned. There is no indication of any primary/secondary leakage. All rods fully inserted on the reactor trip and remain inserted. The electrical alignment is normal with shutdown power supplied from off-site power. The 2B-B Emergency Diesel Generator is currently in service for the performance of an unrelated surveillance. There is no operational impact to Unit 2. Unit 2 continues to operate in Mode 1 at 100%. There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector. The cause of the main generator lockout is under investigation.
ENS 512118 July 2015 15:37:00Indian PointManual ScramNRC Region 1Westinghouse PWR 4-LoopIndian Point Unit 3 was manually tripped at 1427 EDT due to lowering steam generator water levels. At 1425 EDT, #31 condensate pump tripped, causing the lowering water levels. There were no immediate complications on the trip and the unit is stable in Mode 3. Auxiliary feedwater actuated as expected and is in service. All rods inserted and decay heat is being rejected to the condensers. Offsite electrical power is in service. Unit 2 is stable at 100% power. The licensee plans on issuing a press release. The licensee notified the NRC Resident Inspector and New York Public Service Commission.
ENS 510609 May 2015 18:19:00Indian PointAutomatic ScramNRC Region 1Westinghouse PWR 4-Loop

At 1750 EDT (05/09/15,) Indian Point Unit 3 experienced a fire on the 31 Main Transformer resulting in a unit trip. An Unusual Event was declared at 1801 EDT. The onsite fire brigade was mobilized. Offsite fire fighting assistance was requested. The fire was reported extinguished at 1815 EDT. The reactor was shutdown by an automatic trip. Plant response to the trip was as expected with no complications. The 31 and 33 Auxiliary Feed Pumps are operating and feeding the steam generators. Accountability is being performed. The plant is stable in mode 3, all control rods fully inserted, with normal offsite electrical power, and decay heat is being released to the main condenser. There was no impact on Unit 2 which continues to operate at 100% power. The licensee has notified the NRC Resident Inspector and state and local authorities. Notified DHS SWO, FEMA OPS Center, DHS NICC Watch Officer, and Nuclear SSA via email.

  • * * UPDATE FROM LUKE HEDGES TO JOHN SHOEMAKER AT 2037 ON 5/9/15 * * *

Oil from 31 Main Transformer has spilled into the discharge canal and has made its way into the river. Plant personnel are sandbagging drains and release paths. IPEC (Indian Point Energy Center) has contacted its environmental contractor, who is expected onsite at 2100 EDT to assist with cleanup. The National Response Center was notified at 1945 EDT and issued notification number 1116011. A message was left with the Westchester County Department of Health at 1953 EDT. The NY State DEC (Department of Environment Conservation) was contacted at 1955 EDT and issued notification number 1501459. The licensee has notified the NRC Resident Inspector. Indian Point Unit 3 remains in an Unusual Event at this time. Notified R1DO (Schroeder).

  • * * UPDATE FROM LUKE HEDGES TO JOHN SHOEMAKER AT 2141 ON 5/9/15 * * *

Indian Point Unit 3 exited the Unusual Event at 2103 EDT. The basis for exiting the Unusual Event is that the fire is out and field operators report they have been successful in cooling the transformer. The licensee has notified the NRC Resident Inspector and state and local authorities. Notified R1DO (Schroeder), R1RA (Lew), NRR (Dean), NRR EO (Morris), NRR EO (Howe), and IRD (Grant). Notified DHS SWO, FEMA OPS Center, DHS NICC Watch Officer, and Nuclear SSA via email.

ENS 510363 May 2015 12:56:00Wolf CreekManual Scram
Automatic Scram
NRC Region 4Westinghouse PWR 4-LoopOn 5/3/2015 during power ascension following Refueling Outage 20, Steam Generator 'C' water level increased rapidly, causing a Feedwater isolation on high Steam Generator water level and an associated Turbine trip. The reactor was subsequently manually tripped. At the start of the event, reactor power was approximately 22%. Plant staff was in the process of transferring from Main Feedwater Bypass Feed Regulating Valve control, used for low power control, to Main Feedwater Regulating Valve control as part of power ascension. When the Main Feedwater Regulating Valve for 'C' Steam Generator (AEFCV-530) was opened, it went to about 80% open, causing an overfeed of the 'C' Steam Generator. High Steam Generator water level in 'C' Steam Generator initiated an automatic Feedwater Isolation Signal, automatic Turbine Trip and automatic trip of the operating main feed pump. The operating crew initiated a manual reactor trip. The Auxiliary Feedwater System automatically initiated as part of the plant response to the feedwater system transient. The plant is presently stable in Mode 3. All equipment functioned normally, except the 'C' Main Feedwater Regulating Valve (AEFCV0530) which did not function to properly control Steam Generator level. This valve did function as designed to close on the Feedwater Isolation Signal. NRC Resident Inspector has been contacted.
ENS 5100423 April 2015 05:25:00CookManual ScramNRC Region 3Westinghouse PWR 4-LoopOn April 23, 2015 DC Cook Unit 2 Reactor was manually tripped due to an uncontrolled cooldown due to two (2) failed open steam dump valves. The cause of the failure is still under investigation. This event is reportable under 10 CFR 50.72(b)(2)(i) Tech Spec Required Shutdown, as a four (4) hour report; 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation, as a four (4) hour report; and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Reactor Protection System (RPS), as an eight (8) hour report. The electrical grid is stable and Unit 2 continues to be supplied by offsite power. All control rods fully inserted. Decay heat is being removed via steam generator Power Operated Relief Valves due to steam dump valves being manually isolated. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the post Trip Review. No radioactive release is in progress as a result of this event. The DC Cook Resident NRC Inspector has been notified. There is no indication of primary to secondary leakage and there is no impact on Unit 1.
ENS 5089314 March 2015 08:07:00VogtleAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopVogtle Unit 2 was operating in Mode 1 at 100% rated thermal power. At 0429 EDT a Unit 2 automatic Reactor Trip and Safety Injection / Steamline Isolation occurred. All systems operated as expected and all control rods fully inserted. The Safety Injection was terminated at 0447 EDT and the emergency operating procedures were exited at 0522 EDT. Unit 2 is stable in Mode 3 with decay heat removal via the Auxiliary Feedwater system and the atmospheric relief valves. A response team is investigating the cause of the event. Unit 1 was unaffected by the event. NRC Senior Resident Inspector was notified and is at plant site for investigation.
ENS 5087811 March 2015 09:30:00SequoyahAutomatic ScramNRC Region 2Westinghouse PWR 4-LoopAt (0621 EDT) on 3/11/2015, Sequoyah Unit 1 reactor/turbine automatically tripped. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal. Unit 1 is currently being maintained in Mode 3 at NOT/NOP, approximately 547 F and 2235 psig, with auxiliary feedwater supplying decay heat removal via the steam generators and condenser steam dumps. The immediate cause of the trip was a Power Range Nuclear Instrumentation negative rate signal, caused by a malfunction in the rod control system. There was no associated work in progress related to this and all systems were normally aligned. Current Temperature and Pressure - temperature is 547 degrees F and stable, pressure is 2235 psig and stable. There is no indication of any primary/secondary leakage. All rods are inserted. Electrical alignment is normal, supplied from Off-Site power. There is no operational impact to Unit 2. Unit 2 continues to operate in Mode 1 at 100%. There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector.
ENS 508593 March 2015 14:21:00ByronAutomatic ScramNRC Region 3Westinghouse PWR 4-LoopIn accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A), this notification reports an automatic reactor trip on Byron Unit 1. The trip occurred following a trip of the Byron Unit 1 East Main Power Transformer (MPT). Initial indications appear that the MPT trip was caused by a large (~ 5 foot) section of ice that fell from a bus bar over the 1E MPT. This ice shorted out a MPT bushing, resulting in the unit trip. Reactor operators performed a manual start of the Auxiliary Feedwater System in response to the unit trip. All other safety systems responded as expected. The plant trip occurred at 1101 CST on March 03, 2015. Unit 1 is presently in Mode 3 and stable. Unit 2, the opposite unit, is operating at 100% power and stable. This condition was entered into the Byron CAP Program. An investigation is in progress to determine the extent of required repairs, if any, required prior to unit restart. This event resulted in the actuation of the Reactor Protection System with a subsequent Reactor Trip and therefore, requires notification to the NRC within 4 hours of discovery in accordance with 10 CFR 50.72(b)(2)(iv)(B). This event resulted in the manual actuation of the Auxiliary Feedwater System and therefore, requires notification to the NRC within 8 hours of discovery in accordance with 10 CFR 50.72(b)(3)(iv)(A). This ENS call will be followed up with a Licensee Event Report (LER) within 60 days. All rods inserted during reactor trip, offsite power and emergency power sources are currently available and decay heat is being removed via the startup feedwater systems. No safety relief valves lifted as a result of the transient. The NRC Resident Inspector and the State of Illinois were notified.
ENS 5085528 February 2015 05:24:00Wolf CreekManual ScramNRC Region 4Westinghouse PWR 4-Loop

Wolf Creek Generating Station performed a planned shutdown for the start of a refueling outage. As part of the procedure GEN 00-005, Minimum Load to Hot Standby, a planned manual reactor trip was initiated from 25 percent power level with the plant in Mode 1. As part of this planned shut down sequence, an anticipated automatic Auxiliary Feedwater (AFW) actuation signal was generated. This is a non-emergency event notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) due to preplanned manual actuation of the reactor protection system and auto-initiation of auxiliary feed water system. All systems and components operated as designed with the exception of the main generator output breakers. They did not open as designed. They were manually opened using the main control room hand switches as directed by EMG ES-02, Reactor Trip Response. The plant is stable in Mode 3 with AFW secured, with plans to cool down and enter Mode 5 for the planned refueling outage. The NRC Resident Inspector has been notified.

  • * * EVENT RETRACTED ON 03/11/15 AT 13:05 EDT FROM BRET DAVIS TO JEFF HERRERA * * *

WCNOC (Wolf Creek Nuclear Operating Corporation) is retracting the 10 CFR 50.72(b)(3)(iv)(A) notification based on further review of the event. A valid AFAS (Auxiliary Feedwater Actuation signal) actuation occurred during the planned shutdown as a result of SG (Steam Generator) water level reaching the lo lo level setpoint. The AFAS actuation was an expected actuation that occurred due to preplanned activities covered by GEN 00-005. On-shift control room personnel were aware that an AFAS actuation would occur as a result of tripping the plant between 30% and 25% power. The AFAS actuated consistent with the planned shutdown with no anomalies. This is consistent with NUREG-1022, Rev. 3, Section 3.2.6 that states, in part: 'With regard to preplanned actuations, operation of a system as part of a planned test or operational evolution need not be reported. Preplanned actuations are those that are expected to actually occur due to preplanned activities covered by procedures. Such actuations are those for which a procedural step or other appropriate documentation indicates that the specific actuation is actually expected to occur. Control room personnel are aware of the specific signal generation before its occurrence or indication in the control room.' The NRC Resident Inspector was notified. Notified R4DO(Okeefe).

ENS 5083921 February 2015 12:46:00Watts BarManual ScramNRC Region 2Westinghouse PWR 4-LoopOn February 21, 2015 at 10:32 EST, Watts Bar Nuclear Plant Unit 1 reactor was manually tripped due to rapidly dropping main condenser vacuum. Concurrent with the reactor trip the Auxiliary Feedwater system actuated as designed. All Control and Shutdown rods fully inserted. All safety systems responded as designed. The unit is currently stable in Mode 3, with decay heat removal via Auxiliary Feedwater and S/G PORVs. Main Steam Isolation Valves are closed. The Station is in a normal shutdown electrical alignment. The cause is currently under investigation. This is being reported under 10CFR 50.72(b)(3)(iv)(A) and 10CFR 50.72 (b)(2)(iv)(B). The NRC Senior Resident has been notified. This event had no affect on Unit 2 (Under Construction)