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 Entered dateSiteScramRegionReactor typeEvent description
ENS 5423925 August 2019 15:51:00Quad CitiesAutomatic ScramNRC Region 3On August 25, 2019, at 1102 (CDT), Quad Cities Unit 1 experienced an automatic scram from 100 percent power. All rods fully inserted and there were no complications. The trip was initiated from a main generator ground fault relay. Troubleshooting of the fault is in progress. All systems responded as designed. There were no systems inoperable and no TS (Technical Specification) action statements were in progress prior to the Reactor Scram. Reactor water level dropped below the Group 2 and Group 3 Reactor Water Level Isolation set-points as expected, and recovered via the Feedwater system. Standby Gas Treatment System auto started and Reactor Building Ventilation Isolation occurred as expected. Unit 1 remains in Mode 3. Decay heat is being removed using the steam bypass valves to the condenser and the safety relief valves did not lift as a result of the trip. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). The NRC Resident Inspector has been notified. Unit 2 was not affected.
ENS 541973 August 2019 06:47:00ClintonAutomatic ScramNRC Region 3

EN Revision Text: AUTOMATIC REACTOR SCRAM ON LOW REACTOR WATER LEVEL At 0226 (CDT), an automatic scram on low reactor water level occurred due to a trip of the 'B' Reactor Feed pump. All control rods fully inserted. Reactor water level 2 was reached and the High Pressure Core Spray system, Reactor Core Isolation Cooling system, Division 3 diesel generator, Standby Gas Treatment Systems 'A' and 'B' and all shutdown safety related service water pumps started as expected. Reactor Core Isolation Cooling and High Pressure Core Spray injected as expected. All level 2 containment isolation signals occurred as expected and all level 2 containment valves closed as expected. Reactor water level is currently being controlled in band by condensate. Reactor pressure is being maintained by main turbine Bypass Valves. This event is being reported under 10 CFR 50.72(b)(2)(iv)(A), for ECCS discharge to RCS; 10 CFR 50.72(b)(2)(iv)(B), for RPS actuation, and 10 CFR 50.72(b)(3)(iv)(A), for specified system actuation. The NRC Senior Resident Inspector has been notified. No safety relief valves lifted during the transient. The plant is in a normal shutdown electrical lineup with all safety equipment available. The licensee notified the Illinois Emergency Management Agency per their communications protocol.

  • * * UPDATE FROM DAVID LIVINGSTON TO HOWIE CROUCH AT 0321 EDT ON 8/4/19 * * *

Following automatic initiation of the High Pressure Core Spray (HPCS) System as described above, the HPCS System was manually secured following station procedures after verification that additional RPV (reactor pressure vessel) injection was no longer required. Securing HPCS injection in this manner prevents automatic restart of the system in the event of a subsequent low RPV level condition, rendering it inoperable. As the HPCS system is considered a single train safety system, this meets the reportability requirements of 10 CFR 50.72(b)(3)(v)(D). This reportable condition was identified following review of post-scram actions. The HPCS system has been restored to a Standby lineup. The licensee will be notifying the NRC Resident Inspector. Notified R3DO (Pelke).

  • * * UPDATE FROM JAMES FORMAN TO KERBY SCALES AT 1545 EDT ON 8/6/19 * * *

Following the scram, the Primary Containment to Secondary Containment and the Drywell to Primary Containment differential pressure limits were exceeded. Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.4, Primary Containment Pressure, and 3.6.5.4, Drywell Pressure, Actions A.1, B.1, and B.2 were entered. Primary Containment to Secondary Containment differential pressure and Drywell to Primary Containment differential pressure were restored to within the LCO limits at 1505 on 8/3/19 and the associated TS Actions were exited. This event is reportable under 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that could have prevented the fulfillment of the primary containment function due to being outside the initial conditions to ensure that drywell and containment pressures remain within design values during a loss of coolant accident. This event is also reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of the drywell and primary containment functions to control the release of radioactive material for the same reason. The licensee notified the NRC Resident Inspector. Notified R3DO (Pelke).

ENS 540984 June 2019 04:10:00LimerickManual ScramNRC Region 1At 0145 EDT, on 6/4/19, Unit 2 was manually scrammed during a Rapid Plant Shutdown. At 64 percent reactor power, a Rapid Plant Shutdown was initiated due to lowering Main Condenser vacuum as a result of the loss of a plant electrical panel that powers Offgas System controls. The shutdown was normal and the plant is stable in Hot Shutdown with normal pressure control via the Main Turbine Bypass Valves to the Main Condenser and normal level control using Feedwater and Condensate. Main Condenser Vacuum has been restored. The licensee notified the NRC Resident Inspector. Additionally, State and local government agencies were notified. Prior to restarting Unit 2, an evaluation needs to be done due to the Unit 1 Diesel currently out of service for maintenance. The Unit 1 Diesel is a power supply for some of the common systems under the Unit 2 Technical Specifications and therefore required.
ENS 540549 May 2019 07:01:00DresdenAutomatic ScramNRC Region 3On May 9, 2019 at 0348 CDT, an automatic scram was received on Unit 2 following a turbine trip. All rods inserted to their full-in positions. All Group 2 and Group 3 automatic isolations actuated as expected. Systems operated as expected. Reactor vessel inventory and pressure are being maintained in normal control bands. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. The NRC Resident Inspector has been notified. Decay heat is being removed using the steam bypass valves to the condenser and the safety relief valves did not lift as a result of the trip.
ENS 5399814 April 2019 03:21:00Nine Mile PointAutomatic ScramNRC Region 1On April 14, 2019 at 0003 (EDT), Nine Mile Point Unit 1 experienced an automatic reactor scram during reactor startup. The cause of the automatic scram was due to high (Reactor Pressure Vessel) pressure following closure of the turbine stop valves. All control rods fully inserted and all plant systems responded per design following the scram. Following the automatic scram, the High Pressure Coolant Injection (HPCI) System automatically initiated as expected. At Nine Mile Point Unit 1, a HPCI System actuation signal on low Reactor Pressure Vessel (RPV) level is normally received following a reactor scram, due to level shrink. HPCI is a flow control mode of the normal feedwater systems, and is not an Emergency Core Cooling System. At 0004, RPV level was restored above the HPCI System low level actuation set point and the HPCI System initiation signal was reset. Pressure control was established on the Turbine Bypass Valves, the preferred system. No Electromatic Relief Valves actuated due to this scram. Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. The offsite grid is stable with no grid restrictions or warnings in effect. The unit is currently implementing post scram recovery procedures. The NRC Resident Inspector has been notified. The Licensee will notify the State of New York.
ENS 5369828 October 2018 08:57:00ClintonAutomatic ScramNRC Region 3At 0445 (CDT), with reactor power less than 1% rated thermal power on Instrument Range Monitor (IRM) ranges 6 and 7, Clinton Power Station received an automatic Reactor Protection System (RPS) actuation. The Reactor Scram Off Normal procedure was entered and all control rods were verified to be fully inserted. The apparent cause of the scram is cold water injection causing an upscale trip of the IRMs due to Motor Driven Reactor Feedwater Pump (MDRFP) Feedwater Regulating valve 1FW004 valve coming off the full shut seat momentarily. All systems responded appropriately following the scram and the plant is currently stable. Clinton Power Station will be proceeding to Mode 4 to support the planned Maintenance Outage. The NRC Senior Resident Inspector has been notified."
ENS 5363030 September 2018 15:29:00Peach BottomAutomatic ScramNRC Region 1On Sunday, September 30, 2018, at 1130 EDT, an automatic scram was received on U3 following a loss of two condensate pumps. Following the reactor scram, water level lowered from normal level of 23" to below 1" which resulted in automatic Group II and Group III isolations. Reactor water level lowered to -48" which resulted in initiation of the High Pressure Coolant Injection and Reactor Core Isolation Cooling systems. Reactor water level and reactor pressure have been restored to their normal bands. All systems responded properly to the event. Unit 3 remains in Mode 3 with reactor pressure being controlled on the turbine bypass valves. The cause and details of the event are under investigation. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(A), 10 CFR 50.72(b)(2)(iv)(B), and 10 CFR 50.72(b)(3)(iv)(A). All control rods inserted. Decay heat is being removed via the main condenser. The NRC Resident Inspector has been notified. A notification to the media and a press release were made. Unit 2 was unaffected and continues coastdown to refueling.
ENS 5362626 September 2018 23:25:00Quad CitiesAutomatic ScramNRC Region 3

On September 26, 2018 at 1908 CDT. an automatic scram was received on U1 following main generator 345 kV output breaker 7-8 trip with 345 kV output breaker 6-7 already opened for maintenance on line 0401. Following the reactor scram, reactor water level decreased to approximately minus 15 inches, which resulted in automatic Group II and Group Ill isolations (expected response). Reactor pressure rose to approximately 1083 psig, and the 3B and 3C low set relief valves opened briefly to control reactor pressure. Reactor water level and reactor pressure have been restored to their normal bands. All systems responded properly to the event. Unit 1 remains in Mode 3, with reactor pressure being controlled on the turbine bypass valves. The cause and details of the event are under investigation.

Unit 2 was unaffected by the event and remains at 100% power. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A)." All control rods inserted. Decay heat is being removed via the main condenser. The licensee notified the NRC Resident Inspector.

ENS 5357631 August 2018 23:26:00LaSalleManual ScramNRC Region 3This notification is being provided in accordance with 10 CFR 50.72(b)(2)(iv)(B). On August 31, 2018 at 2105 CDT, Unit 2 Reactor Manual Scram signal was inserted due to Main Condenser vacuum degrading. The turbine was tripped following the scram. Main Condenser vacuum is at 6 inches of backpressure slowly improving following the scram and turbine trip. During the scram, one Control Rod (30-31) did not fully insert. Control Rod 30-31 has been manually inserted to position 00 with the first position identified as position 24. Plant is in a stable condition with reactor pressure being maintained by the Turbine Bypass valves. Reactor water level is being controlled with feedwater. Investigation into the cause of the elevated condenser in leakage is in progress. The Senior NRC Resident has been notified."
ENS 5356527 August 2018 03:12:00Nine Mile PointAutomatic ScramNRC Region 1

EN Revision Text: AUTOMATIC SCRAM DUE TO A GENERATOR TRIP At 0033 EDT Nine Mile Point Unit 2 experienced an automatic scram on high reactor pressure due to a turbine trip. The cause of the turbine trip was due to a generator trip. All control rods inserted. There were no safety system actuations. The cause of the generator trip is being investigated. This is a 4-Hour report for 10CFR50.72(b)(2)(iv)(B) RPS Actuation. The NRC Resident Inspector has been notified. Decay heat is being removed via the main condenser. Reactor vessel water level is being maintained by the condensate and feedwater systems. The licensee will be notifying the state of New York.

  • * * UPDATE FROM DANIEL CIFONELLI TO HOWIE CROUCH AT 1653 EDT ON 8/28/18 * * *

After further review, the licensee has determined that the cause of automatic scram was due to turbine control valve fast closure as a result of the turbine trip, not high reactor pressure, as originally reported. The licensee has notified the NRC Resident Inspector. Notified R1DO (Lilliendahl).

ENS 534434 June 2018 14:00:00BraidwoodManual ScramNRC Region 3At 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 14:53:00BraidwoodAutomatic 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 531109 December 2017 18:42:00ClintonManual ScramNRC Region 3GE-6

At approximately 1347 (CST) on 12/09/17, the Main Control Room received annunciators that indicated a trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1 breaker. Numerous Division 1 components lost power (powered from unit subs 1A and A1). The Division 1 containment Instrument Air isolation valves had failed closed by design due to the loss of power. Due to the loss of containment instrument air, several control rods began to drift into the core as expected and, by procedure, the reactor mode switch was placed in the shutdown position at 1353 (CST). All control rods fully inserted. Also due to the loss of power, the Fuel Building ventilation dampers failed closed by design. With the normal ventilation system secured, secondary containment differential pressure rose to slightly greater than 0 inches water gauge which exceeded the Technical Specification requirement of greater than 0.25 inches vacuum water gauge at 1348 (CST). The Control Room entered EOP-8, Secondary Containment Control. Secondary Containment differential pressure was restored within Technical Specification requirements at 1351 (CST) by starting the Division 2 Standby Gas Treatment system. This event is being reported as a manual actuation of the Reactor Protection System (RPS) and as a Condition that Could Have Prevented Fulfillment of a Safety Function.

The cause is currently under investigation. The NRC Resident has been notified. The licensee informed the NRC Resident Inspector.

  • * * UPDATE FROM DALE SHELTON TO VINCE KLCO AT 1658 EST ON 12/10/2017 * * *

During a review of plant logs it was identified that the primary to secondary containment differential pressure was identified to be outside of Technical Specification 3.6.1.4 limits of 0 plus or minus 0.25 psid at 2009 on 12/9/17 due to the primary containment ventilation system dampers closing as a result of the loss of power. This parameter is an initial safety analysis assumption to ensure that primary containment pressures remain within the design values during a Loss of Coolant Accident (LOCA). As a result, this condition is reportable as an unanalyzed condition that significantly degrades plant safety. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone).

  • * * UPDATE FROM MICHAEL ANTONELLI TO VINCE KLCO ON 12/11/17 AT 1805 EST * * *

During the post transient review of the trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1, it was identified that the unplanned INOPERABILITY of the Low Pressure Core Spray (LPCS) system due to the loss of power to the injection valve constitutes an event or condition that could have prevented fulfillment of a safety function and is reportable under 10CFR50.72(b)(3)(v)(D) for Accident Mitigation. The High Pressure Core Spray (HPCS) remained available to perform the core spray function, if necessary, during a design basis Loss of Coolant Accident (LOCA), however HPCS and LPCS are each considered single train safety systems. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone).

ENS 529506 September 2017 15:41:00Nine Mile PointAutomatic ScramNRC Region 1GE-2On September 6, 2017 at 1157 (EDT), Nine Mile Point Unit 1 experienced an automatic reactor scram with a Main Steam Isolation Valve (MSIV) and Containment isolation. The scram was due to reactor vessel low water level. The cause of the reactor vessel low water level is under investigation. All control rods fully inserted. Following the scram, pressure was momentarily controlled through the use of the Emergency Condenser (EC) system. At 1205, pressure control was established through the main steam lines to the condenser through the turbine bypass valves. All plant systems responded per design following the scram. The reactor scram is a 4-hour report per 10 CFR 50.72(b)(2)(iv)(B). The following systems automatically actuated after the scram as expected. These system actuations are an 8-hour report per 10 CFR 50.72(b)(3)(iv)(A): 1. The High Pressure Coolant Injection (HPCI) system. HPCI initiated at 1157 and was reset at 1158 when RPV level was restored above the HPCI system low level actuation set point. HPCI is a flow control mode of the normal feedwater systems, and is not an Emergency Core Cooling System. 2. The Core Spray system actuated, but did not discharge to the Reactor Coolant system. The Core Spray system was secured at 1216. 3. Containment and MSIV isolation on reactor vessel low-low water level signal. Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor vessel water level and pressure maintained within normal bands. Decay heat is being removed via steam to the main condenser using the turbine bypass valves. The offsite grid is stable with no grid restrictions or warnings in effect. The licensee has notified the NRC Resident Inspector. No safety relief valves lifted during the transient. The main steam isolation valves were opened after the isolation signal cleared to facilitate decay heat removal. Offsite power is supplying all plant loads. There was no effect on Unit 2. The licensee notified New York State Department of Environmental Protection and will be issuing a press release.
ENS 528896 August 2017 00:26:00Nine Mile PointAutomatic ScramNRC Region 1GE-5At 2235 (EDT) Nine Mile Point Unit 2 experienced an automatic scram on high reactor pressure. Turbine stop valve testing was in progress at the time of the scram. All control rods inserted. Pressure control is via the turbine bypass valves. The cause of the scram is being investigated. This is a 4-Hour report for 10CFR50.72(b)(2)(iv)(B) RPS (Reactor Protection System) Actuation. The NRC Resident Inspector has been notified. Reactor water level is being maintained with normal feedwater flow. No safety or relief valves lifted. The plant is in its normal shutdown electrical lineup.
ENS 528393 July 2017 12:32:00Oyster CreekManual Scram
Automatic Scram
NRC Region 1GE-2At 1015 (EDT) a manual reactor scram was inserted due to degrading main condenser vacuum. All rods inserted into the core as expected and all systems functioned as expected during the scram. This event is reportable within 4 hours per 10 CFR 50.72(b)(2)(iv)(B) 'any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.' At 1033 (EDT) an automatic reactor scram occurred on low reactor water level. Due to the previous manual reactor scram, all rods were (already) inserted. This event is reportable within 8 hours per 10 CFR 50.72(b)(3)(iv)(A) 'any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section, except when the actuation results from and is part of a preplanned sequence during testing or reactor operation. (1) Reactor protection system (RPS) including : Reactor scram and reactor trip.' Decay heat is being removed using main feedwater and the turbine bypass valves. The licensee notified the NRC Resident Inspector. This event was characterized as a "configuration control event" where a valve misposition allowed the offgas line to flood.
ENS 5280011 June 2017 01:00:00ClintonManual ScramNRC Region 3GE-6At 2256 CDT on 6/10/17, Clinton operators manually scrammed the reactor from 99 percent power due to a loss of feedwater heating. The scram was uncomplicated and the plant is stable and in mode 3. All rods inserted and decay heat is being removed by the condenser. All offsite power is available. The cause of the loss of feedwater heating is under investigation. The NRC Resident Inspector and the State of Illinois have been notified.
ENS 5262420 March 2017 04:40:00Nine Mile PointManual ScramNRC Region 1GE-2On March 20, 2017 at 0227, Nine Mile Point Unit1 was manually scrammed due to pressure oscillations. The Unit was offline and reactor shutdown was in-progress at the time of the scram. The scram was inserted at approximately 4% reactor power when pressure oscillations occurred exceeding the procedurally required limit for pressure oscillations. The cause of the scram was due to Operators manually inserting the scram. The cause of the pressure oscillations is being investigated. The licensee notified the NRC Resident Inspector. Notified the R1DO (Gray).
ENS 5256418 February 2017 02:58:00LaSalleManual Scram
Automatic Scram
NRC Region 3GE-5

This notification is being provided in accordance with 10CFR 50.72(b)(2)(iv)(B). On February 17, 2017 at 2353 CST, Unit 1 Reactor Automatic Scram signal was received due to Turbine Control Valves Fast Closure. The turbine trip was due to receipt of Level 8 Trip due to a failure of the Feedwater Regulating Valve to Full open. Plant is in a stable condition with reactor pressure being maintained by the Turbine Bypass valves. Reactor water level is being controlled with Feedwater thru the Low Flow Feedwater Regulating Valve. Further investigation into the cause of the event is in progress. All control rods fully inserted, and decay heat is being removed via steam to the main condenser using bypass valves. The licensee has notified the NRC Resident Inspector.

  • * * UPDATE FROM BROCK POLLMANN TO HOWIE CROUCH AT 1721 EDT ON 4/14/17 * * *

Upon further review of the event data, it was determined that the Nuclear Station Operator (NSO) had initiated a manual scram, which was followed by a Turbine Control Valve (TCV) fast closure automatic scram when the turbine tripped. The licensee has notified the NRC Resident Inspector. Notified R3DO (Jeffers).

ENS 5254714 February 2017 02:40:00LaSalleAutomatic ScramNRC Region 3GE-5This notification is being provided in accordance with 10 CFR 50.72(b)(2)(iv)(B). On February 13, 2017 at 2309 CST, a Unit 1 Reactor Automatic Scram signal was received due to Turbine Control Valve Fast Closure. The turbine trip was due to the main generator trip on Differential Current. The 'U' safety relief valve actuated in the relief mode on the turbine trip, and has subsequently reset with tailpipe temperature returning to normal. The plant is in a stable condition with reactor pressure being maintained by the Turbine Bypass valves. Reactor water level is being controlled with feedwater. Investigation into the cause of the event is in progress. All control rods fully inserted on the scram. Unit 1 is in a normal shutdown electric plant alignment. Unit 2 was not affected. The licensee notified the NRC Resident Inspector.
ENS 5250523 January 2017 10:34:00LaSalleManual ScramNRC Region 3GE-5This notification is being provided pursuant with 10 CFR 50.72 (b)(2)(iv)(B). (On January 23, 2017) at 0806 (CST), Unit 2 Manual Scram was inserted due to a Stator Water Cooling runback signal and a Turbine Bypass Valve opening. The Plant is stable, reactor pressure is being maintained with Bypass valves. Reactor water level is being controlled with feedwater. Investigation into the cause of the event is in progress. All control rods fully inserted. The licensee has notified the NRC Resident Inspector.
ENS 5242510 December 2016 12:31:00Nine Mile PointManual ScramNRC Region 1GE-2On December 10, 2016 at 0848 EST, (operators at) Nine Mile Point Unit 1 manually scrammed the reactor due to high vibrations on the Main Turbine. Cause of the high vibrations is being investigated. Following the scram, the High Pressure Coolant Injection (HPCI) system automatically initiated as expected. At Nine Mile Point Unit 1, a HPCI system actuation signal on low reactor pressure vessel (RPV) level is normally received following a reactor scram, due to level shrink. HPCI is a flow control mode of the normal feedwater system and is not an emergency core cooling system. At 0849, RPV level was restored above the HPCI system low level actuation set point and the HPCI system initiation signal was reset. Pressure control was established on the turbine bypass valves, the preferred system. No Electromatic relief valves actuated due to this scram. Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. Decay heat is being removed via steam to the main condenser using the bypass valves. The offsite grid is stable with no grid restrictions or warnings in effect. The unit is currently implementing post scram recovery procedures. The licensee has notified the state of New York Public Service Commission and the NRC Resident Inspector.
ENS 524064 December 2016 01:48:00Calvert CliffsAutomatic ScramNRC Region 1CEOn 12/3/16 at 2224 EST, Calvert Cliffs Unit-2 experienced an automatic reactor trip from full power due to a leak in the Unit-2 Main Turbine Electro-Hydraulic Control (EHC) system. The EHC leak caused the Unit-2 Main Turbine governor valves to close, resulting in a turbine trip and automatic reactor trip. The site Outage Control Center is manned, and investigation into the cause of the leak is underway. Unit-2 remains stable in Mode 3 with normal heat removal. Unit-1 remains at full power and was not affected by the trip. The plant is in a normal shutdown electrical lineup. All Control rods fully inserted and no primary or secondary safety relief valves lifted during the trip. The licensee has notified the NRC Resident Inspector. The licensee will be notifying Calvert County.
ENS 5238120 November 2016 06:01:00Oyster CreekAutomatic ScramNRC Region 1GE-2At 0342 EST, an automatic reactor scram was processed during turbine valve testing. All rods inserted into the core as expected and all systems functioned as expected during the scram. The event is reportable within 4 hours per 10 CFR 50.72(b)(2)(iv)(B) - any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical except when the actuation results from and is part of a preplanned sequence during testing or reactor operation. The plant response to the reactor scram was uncomplicated. The main feedwater system is maintaining reactor water level and decay heat is being removed by the main turbine bypass valves to the main condenser. The unit is in a normal shutdown electrical lineup. No SRVs lifted during the scram. The licensee was testing the main turbine trip function just prior to the scram. The cause is under investigation. 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 5204224 June 2016 16:06:00FitzPatrickManual ScramNRC Region 1GE-4At 1215 (EDT) on 6/24/2016, James A. FitzPatrick (JAF) was at 100% power when Breaker 710340 tripped and power was lost to L-gears L13, L23, L33, and L43. These provide non-vital power to Reactor Building Ventilation (RBV), portions of Reactor Building Closed Loop Cooling (RBCLC), and 'A' Recirculation pump lube oil systems. Off-site AC power remains available to vital systems and Emergency Diesel Generators (EDG) are available. Due to the loss of RBV, Secondary Containment differential pressure increased. At 1215 (EDT), Secondary Containment differential pressure exceeded the Technical Specifications (TS) Surveillance Requirement SR-3.6.4.1.1 of greater than or equal to 0.25 inches of vacuum water gauge. The Standby Gas Treatment (SBGT) system was manually initiated and Secondary Containment differential pressure was restored by 1219 (EDT). The 'A' Recirculation pump tripped at 1215 (EDT) and reactor power decreased to approximately 50%. 'B' Recirculation pump temperature began to rise due to the degraded RBCLC system. At 1236 (EDT), a manual scram was initiated. Reactor Pressure Vessel (RPV) water level shrink during the scram resulted in a successful Group 2 isolation. All control rods have been inserted. The RPV water level is being maintained with the Feedwater System and pressure is being maintained by main steam line bypass valves. A cooldown is in progress and JAF will proceed to cold shutdown (Mode 4). Due to complete loss of RBCLC system, the Spent Fuel Pool (SFP) cooling capability is degraded but the Decay Heat Removal system remains available. SFP temperature is slowly rising and it is being monitored. The time (duration) to 200 degrees is approximately 117 hours. The initiation of reactor protection systems (RPS) due to the manual scram at critical power is reportable per 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). The general containment Group 2 isolations are reportable per 10 CFR 50.72(b)(3)(iv)(A). In addition, the temporary differential pressure change in Secondary Containment is reportable per 10 CFR 50.72(b)(3)(v)(C), as an event that could have prevented fulfillment of a safety function. The licensee notified the NRC Resident Inspector and the State of New York.
ENS 5203322 June 2016 13:02:00Fort CalhounAutomatic ScramNRC Region 4At 0841 (CDT) an automatic turbine trip occurred, resulting in an automatic reactor protective system (RPS) actuation due to loss of turbine load. The source of the turbine trip was from the distributed control system (DCS) and is being investigated via a root cause analysis. This was an uncomplicated trip, all systems responded as expected post trip, and the reactor trip recovery procedure was entered at 0852 (CDT). The plant is stable in Mode 3 with a normal electrical line up and decay heat removal via steam dumps to the condenser. The NRC Resident Inspector has been notified.
ENS 519681 June 2016 10:40:00LimerickManual ScramNRC Region 1GE-4Limerick Unit 2 was manually scrammed from 100 (percent) power at 0900 (EDT) on 6/1/2016 in accordance with plant procedure OT-112 'Unexpected/Unexplained change in core flow' when both 2A and 2B Recirculation Pump Adjustable Speed Drives (ASDs) tripped due to an electrical fault. The shutdown was normal and the plant is stable in Hot Shutdown with normal pressure control via the Main Steam Bypass valves to the Main Condenser and normal level control using Feedwater. The Manual RPS actuation is reportable under 10 CFR 50.72 (b)(2). All rods inserted fully on manual scram and the plant is in a normal shutdown electrical line up. Unit 1 was not affected by this event. The licensee plans to issue a press release. The licensee notified local counties and Pennsylvania Emergency Management Agency (PEMA). The NRC Resident Inspector has been notified.
ENS 5189530 April 2016 19:14:00Oyster CreekManual ScramNRC Region 1GE-2Today at 1804 EDT, a manual scram was processed during startup due to rising unidentified leak rate. The rise in unidentified leak rate was identified to be coming from the D Reactor Recirc Pump seal cavity. All rods inserted into the core and all systems functioned as expected during the scram. The event is reportable within 4 hours per 10 CFR 50.72(b)(2)(iv)(B) - any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. The reactor is stable in hot shutdown. The licensee notified the NRC Resident Inspector.
ENS 5168325 January 2016 05:45:00Calvert CliffsManual ScramNRC Region 1CEAt 0315 EST on 1/25/16, Calvert Cliffs Unit 1 was manually tripped from 10 percent power due to elevated condenser sodium levels. All systems responded per design. Main Feed was secured and auxiliary feed water was initiated. The elevated sodium levels are believed to be due to a condenser tube leak. The reactor is currently shutdown and stable in Mode 3 and will remain in Mode 3 until repairs are effected. Unit 2 was not affected and remains at full power. The Licensee has notified the NRC Resident Inspector.
ENS 5168024 January 2016 01:10:00FitzPatrickManual ScramNRC Region 1GE-4At 2241 (EST) on 1/23/2016, James A FitzPatrick inserted a manual scram from 89 percent power due to lowering intake level. Following the successful scram, a residual transfer occurred, resulting in a loss of the non-vital busses, loss of all Circulating Water Pumps, and a manual closure of the Main Steam Isolation Valves (MSIVs). The cause of the residual transfer is unknown. RPV (Reactor Pressure Vessel) level shrink during the scram resulted in a successful Group 2 isolation. Reactor Vessel (level) and pressure are being maintained with the High Pressure Coolant Injection System which was manually started. A cooldown is in progress. FitzPatrick will proceed to Mode 5 until the cause is identified and corrected. The Emergency Diesel generators auto started as a result of the loss of power to the non-vital busses. Offsite power remained available throughout the event. Operators are controlling pressure manually via the relief valves. FitzPatrick will notify the Public Service Commission of the event. The NRC Resident Inspector was notified.
ENS 5161419 December 2015 10:38:00LimerickAutomatic ScramNRC Region 1GE-4At 0702 EST on 12/19/2015, the Unit 2 reactor automatically scrammed on a valid reactor low level signal (12.5 inches). The reactor low level signal was caused by the trip of the in-service 2A Reactor Feedwater Pump, causing reactor level to lower, exceeding the low reactor level setpoint of 12.5 inches. The shutdown was normal. The plant is stable in Hot Shutdown with normal reactor level, pressure control via the Main Steam Bypass Valves to the Main Condenser and normal level control using the Condensate System. High level trip of the 2A Reactor Feedwater Pump was caused by high reactor level of +54 inches following opening of bypass valves during reactor start-up and pressurization. The cause is still being investigated. All systems functioned as expected following the reactor scram. The licensee notified the NRC Resident Inspector.
ENS 515771 December 2015 20:25:00Calvert CliffsManual ScramNRC Region 1CEOn 12/01/2015 at 1820 EST, the Main Control Room received a 22 Steam Generator Feed Pump trip. The 22 Steam Generator Feed Pump was not able to be reset and the Main Control Room manually tripped the Unit 2 Reactor. The licensee entered Emergency Operating Procedure (EOP)-0, 'Post Trip Immediate Actions' and all safety functions were met. At 1833, Unit 2 transitioned into EOP-1, 'Uncomplicated Reactor Trip.' At 1841, Unit 2 transitioned into Operating Procedure #4 , 'Plant Shutdown from Power to Hot Stand-by.' The plant is stable in Mode 3. All control rods inserted fully on the reactor trip. No primary or secondary safety relief valves lifted. The steam generators are being fed by the 21 steam generator feed pump and decay heat is being dumped to the condenser via the steam dumps. The electric plant is in a normal shutdown electrical lineup and there was no impact on Unit 1. Unit 1 continues to operate at 100 percent power. The cause of the 22 steam generator feed pump trip is still under investigation. The licensee notified the NRC Resident Inspector.
ENS 513694 September 2015 12:58:00Nine Mile PointAutomatic ScramNRC Region 1GE-2On September 4, 2015, at 0916 (EDT), Nine Mile Point Unit 1 experienced an automatic reactor scram following Main Steam Isolation Valve (MSIV) closure and isolation of both main steam lines. The cause of the MSIV closure is not known at this time. All control rods fully inserted. Following the scram, pressure was momentarily controlled through the use of the Emergency Condenser system. At 0950, pressure control was established through the main steam lines to the condenser through Main Steam Isolation Valves (MSIVs) 01-02 and 01-04. MSIV 01-03 would not reopen. All other plant systems responded per design following the scram. The reactor scram is a 4-hour report per 10 CFR 50.72(b)(2)(iv)(B)." The following systems automatically actuated after the scram as expected. These system actuations are an 8-hour report per 10 CFR 50.72(b)(3)(iv)(A). 1. The High Pressure Coolant Injection (HPCI) system. HPCI initiated at 0916 and reset at 0917 when RPV level was restored above the HPCI system low level actuation set point. HPCI initiated and was reset a second time at 0922. HPCI is a flow control mode of the normal feedwater systems, and is not an Emergency Core Cooling System. 2. The Core Spray system actuated, but did not discharge to the Reactor Coolant system. The Core Spray system was secured at 1033. 3. The Emergency Condenser (EC) system actuated to control pressure. EC-11 was secured at 0917. EC-12 was secured at 0921 . The maximum shell temperature of EC system was 193 degrees Fahrenheit. 4. Containment Isolation actuation. Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. Since the scram, there have been no anomalies observed with feedwater system operation. Decay heat is being removed via steam to the main condenser using the turbine bypass valves. The offsite grid is stable with no grid restrictions or warnings in effect. The Reactor is being supplied by the normal feedwater system and there was indication of a partial lift/reset on one Electrometric Relief Valve (ERV). The licensee notified the NRC Resident Inspector and the State of New York Public Service Commission.
ENS 510557 May 2015 18:55:00Oyster CreekAutomatic ScramNRC Region 1GE-2Today at 1727 EDT, an automatic scram from a turbine trip occurred. The cause of the turbine trip is currently under investigation. All rods inserted into the core and all systems functioned as expected during the scram. The event is reportable within 4 hours per 10CFR50.72(b)(2)(iv)(B) - any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. Plant response to the scram was uncomplicated and the plant is stable in Mode 3. The licensee has notified the NRC Resident Inspector.
ENS 5098113 April 2015 09:56:00LimerickManual ScramNRC Region 1GE-4Following a pre-planned scram for entry into the U2 Refueling Outage, the 'B' Reactor Protection system (RPS) was unable to be reset due to a deficiency with the '2H' Intermediate Range Power Monitor. Due to this failure to reset RPS, a manual full scram was initiated as required by plant procedures. The licensee notified the NRC Resident Inspector.
ENS 509617 April 2015 15:45:00Calvert CliffsAutomatic ScramNRC Region 1CE

A loss of Main Generator Load which caused a Reactor Trip on Units 1 & 2. A switchyard voltage transient from a highline occurred, which caused an undervoltage condition on both units' safety related 4KV buses. Unit 1 is on normal heat removal to the condenser. Unit 2 is on auxiliary feedwater and normal condenser bypass valves for temperature control. An Auxiliary Feedwater Actuation System (AFAS) actuation occurred on Unit 2. The (Unit 2) 2B emergency diesel generator did not start and load on its respective 24-4 KV bus. The 24-4KV Bus was repowered from the alternate feeder breaker. Cause of the emergency diesel failure to start is under investigation. All safety functions are met for both units. All control rods fully inserted. The site is in a normal shutdown electrical configuration powered from offsite. The site plans to stay in Mode 3 pending restart. The licensee notified the NRC Resident Inspector, State and local authorities. A press release is planned.

  • * * UPDATE FROM JAY GAINES TO DANIEL MILLS AT 0129 EDT ON 4/9/2015 * * *

During post trip review, it was determined that the 21 saltwater pump had to be manually started. With the failure of 2B emergency diesel generator, there were no saltwater pumps running for approximately 12 minutes. Additional troubleshooting determined the 2A emergency diesel generator sequencer did not automatically start 21 saltwater pump. The 2B emergency diesel generator was returned to service on 4/8/2015 at 1730 (EDT). The loss of saltwater (pump) and emergency diesel generator is reportable as an event that could have prevented fulfillment of a safety function and is also an unanalyzed condition. The licensee has notified the NRC Resident Inspector. Notified R1DO (Ferdas), IRD MOC (Grant), NRR EO (Morris).

ENS 509493 April 2015 01:32:00Quad CitiesManual ScramNRC Region 3GE-3On April 2, 2015 at 2133 CDT, a manual scram was inserted on Unit 1 following discovery of a steam leak in the Turbine Building at the D-ring, near the Turbine Bypass valves. Following the reactor scram, reactor water level decreased to approximately -2 inches, which resulted in an automatic Group II and Group III isolation (expected response). The steam leak was isolated by manual closure of the Main Steam Isolation Valves. All systems responded properly to the event. Unit 1 remains in Mode 3, with cooldown in progress. Reactor water level is in the normal level band. The cause and details of the event are under investigation. Unit 2 was unaffected by the event and remains at 100 percent power. Operators reduced reactor power to 20 percent before initiating a SCRAM. All rods fully inserted and the reactor is shutdown and stable. The electrical supply is in a normal shutdown lineup. The reactor is being supplied by normal feedwater, and decay heat is being controlled by use of the ADS valves. The licensee is currently cooling down and depressurizing the reactor in preparation for repair of the steam leak. The licensee has notified the NRC Resident Inspector and the State of Illinois 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 5084724 February 2015 01:02:00LimerickAutomatic ScramNRC Region 1GE-4At 2140 EST on 02/23/2015, Unit 1 reactor automatically scrammed on a valid reactor high pressure signal (1096#). The reactor high pressure signal was caused by the closure of the 1C inboard main steam isolation valve (MSIV), causing reactor pressure to rise, exceeding the reactor protection system (RPS) setpoint of 1096# pressure. The shutdown was normal and the plant is stable in Hot Shutdown with normal pressure control via the main steam bypass valves to the main condenser and normal level control using the feedwater system. The closure of the 1C inboard MSIV appears to have been caused by a loss of primary containment instrument gas (PCIG) pneumatic supply to the valve. Instrument air was aligned to the remaining MSIV's. Limerick Unit 1 will remain in Hot Shutdown until repairs can be made. All rods inserted into the core during the scram. No relief or safety valves actuated during the transient. The electric grid is stable and supplying all plant loads. There was no affect on Unit 2. The licensee notified the NRC Resident Inspector, Pennsylvania Emergency Management Agency, and Berks, Chester and Montgomery counties.
ENS 5083018 February 2015 16:01:00Nine Mile PointManual ScramNRC Region 1GE-5At 1406 (EST) Nine Mile Point Unit 2 inserted a manual scram due to rapidly rising reactor water level. The cause of the rapidly rising water prior to the manual scram is unknown and under investigation. Reactor water level is currently being maintained in normal control band post scram. The reactor scram is reportable in accordance with 10 CFR 50.72(b)(2)(iv)(B) as, 'Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical.' The NRC Resident has been notified. All rods fully inserted. Nine Mile Point Unit 2 is in a normal electrical shutdown configuration. The licensee reported no impact on Unit 1. The New York State Public Service Commission was also notified.
ENS 507926 February 2015 16:53:00DresdenAutomatic ScramNRC Region 3GE-3At 1227 CST on 06 Feb 2015, Dresden Unit 2 automatically scrammed due to a Reactor Water Level transient. Set up activities for weekend maintenance were being performed on the feedwater system at the time of the event. All rods inserted to their full-in positions. Systems operated as expected. Reactor vessel inventory and pressure are being maintained in normal control bands. The ultimate heat sink was maintained. The source of the transient was a loss of Feedwater Level Control and the reactor automatically scrammed on low reactor water level. Cause of the failure is under investigation. All three feed pumps tripped as a result of the transient. The 2B reactor feed pump was restored following the transient in accordance with station operating procedures. Level is being maintained with normal feedwater. High Pressure Coolant Injection initiated on a valid low-low reactor water level. Manual operator action was taken to prevent unneeded injection into the reactor coolant system. Group 2 Primary Containment and Group 3 Shutdown Cooling and Reactor Water Clean-up system isolations occurred as expected. Unit 2 and 2/3 (swing diesel) EDGs started as expected, but did not load onto their associated busses as offsite power was maintained. The licensee has notified the NRC Resident Inspector.
ENS 5073313 January 2015 22:10:00DresdenManual ScramNRC Region 3GE-3At 1904 Central Time 13 Jan 2015, Dresden Unit 2 was manually scrammed by Operators due to a Reactor Water Level transient. All rods inserted to their full-in positions. All systems operated as expected. Reactor vessel inventory and pressure are being maintained in normal control bands. The source of the transient was a failure of both controllers in the Feedwater Level Control system. Cause of the failure is under investigation. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (R) when the reactor is critical. There was no on-going work or testing during this time which could be attributed to the failure of the level controllers. Unit 2 is in a normal post scram electrical line-up and maintaining pressure and temperature. RHR cooling is available if required. Unit 3 was unaffected by this transient. The licensee informed the NRC Resident Inspector.
ENS 5068817 December 2014 12:56:00Fort CalhounAutomatic ScramNRC Region 4At 1014 (CST) on 12/17/2014, the reactor automatically tripped due to loss of load on RPS (Reactor Protection System). Preliminary information indicates turbine-generator trip caused an uncomplicated reactor trip . All safety functions are met. Currently maintaining Mode 3, Hot Shutdown. At time of trip, non-safety related house transformers, T1A1 and T1A2 became inoperable as expected due to generator trip. Entered Technical Specification 2.7 (2)a, 72 hr LCO (for the inoperable T1A1 and T1A2 transformers). All control rods fully inserted. All busses are energized via offsite power. Decay heat is being released via AFW and the condenser bypass valves. The unit is stable in Mode 3. Cause of the loss of load is being investigated. The NRC Resident Inspector has been informed.
ENS 5052412 October 2014 05:22:00Oyster CreekManual Scram
Automatic Scram
NRC Region 1GE-2

Today at approximately 0250 (EDT) (on 10/12/14), during a planned reactor power ascension with reactor power at approximately 1% of rated thermal power, reactor water level began lowering. Operators inserted a manual SCRAM at 0251 (EDT) in accordance with station procedures. The cause of the lowering reactor level is currently under investigation. All rods inserted into the core and all systems functioned as expected during the scram. No electromatic (EMRVs) or safety relief valves lifted during the transient. The plant is currently shutdown and plant parameters are stable. This event is reportable per 10CFR50.72(b)(2)(iv)(B) - 'any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.' Decay heat is being released to the main condenser and normal offsite power is being maintained. The licensee has notified the NRC Resident Inspector.

  • * * UPDATE PROVIDED BY JOSH MCGUIRE TO JEFF ROTTON AT 1520 EDT ON 10/17/2014 * * *

An automatic SCRAM occurred at 0251 EDT, moments before operators inserted a manual SCRAM in accordance with station procedures. The licensee notified the NRC Resident Inspector. Notified R1DO (Cook).

ENS 5027011 July 2014 05:17:00Oyster CreekManual ScramNRC Region 1GE-2Today at approximately 0312 (EDT on 7/11/14), during a planned reactor power ascension with reactor power at approximately 55 percent of rated thermal power, main condenser vacuum began to lower. In accordance with the abnormal operating procedure for degrading vacuum, Operators inserted a manual scram of the reactor at 0314 (EDT). The cause of the degraded vacuum is currently under investigation. All rods inserted into the core and all systems functioned as expected during the scram. No electromatic (EMRVs) or safety relief valves lifted during the transient. This event is reportable within 4 hours per 10CFR50.72(b)(2)(iv)(B) - any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. The scram was uncomplicated, normal offsite power is available, and plant is being cooled down to cold shutdown. The cause of the degraded condenser vacuum is suspected condenser boot degradation. The licensee has informed the NRC Resident Inspector.
ENS 500853 May 2014 15:15:00DresdenAutomatic ScramNRC Region 3GE-3At 1209 CDT on 3 May 2014, Dresden Unit 2 automatically scrammed on a Generator-Turbine Load Mismatch signal following a main generator trip. All rods inserted to their full in positions. All systems operated as expected. Reactor vessel inventory and pressure are being maintained in automatic. The cause of the scram was due to a main generator trip that occurred during a voltage regulator channel transfer. Troubleshooting is in progress to determine the exact cause of the generator trip. This condition is being reported pursuant to 10CFR50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. The plant is in a normal shutdown electrical lineup. Main feedwater is being used to maintain reactor vessel level and decay heat is being removed by the main condenser via the turbine bypass valves. There was no impact on Unit 3 which remains stable at 100 percent power. The licensee notified the NRC Resident Inspector.
ENS 5003012 April 2014 13:24:00DresdenAutomatic ScramNRC Region 3GE-3At 1012 CDT on April 12, 2014, Dresden Unit 2 automatically scrammed on TR-2 sudden pressure relay actuation. All rods inserted to their full-in positions. Following the reactor scram, the 'A' reactor recirculation pump did not run back to minimum speed automatically. Operators took action to run the recirculation pump to minimum speed manually. All other systems operated as expected. Reactor vessel inventory and pressure are being maintained in automatic. The cause of the scram was due to a trip of the sudden pressure relay for Main Power Transformer 2. Troubleshooting is in progress to determine the cause (of the trip of the sudden pressure relay). This condition is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. Normal offsite power remains available. There was no impact on Unit 3. The NRC Resident Inspector has been informed.
ENS 499882 April 2014 15:32:00Quad CitiesManual ScramNRC Region 3GE-3

Quad Cities Unit 2 Alert Classification (HA3) Due to Fire. On April 2, 2014, at 1340 CDT, an ALERT was declared due to a fire in the Unit 2 turbine building. Prior to declaring the ALERT, Unit 2 was manually scrammed at 1302 CDT. All control rods inserted and all automatic isolations actuated as designed. The Main Steam Isolation Valves were manually closed. The fire has been extinguished. Unit 2 is currently in Hot Shutdown. The cause of the event is under investigation. Unit 1 remains at 100% power. The Senior Resident Inspector has been notified of the event. Unit 2 is still being supplied from off-site power and is in a normal shutdown electrical lineup with the exception of Bus 29-1 (480 VAC safety bus) that was deenergized. One Unit 2 emergency diesel generator is inoperable due to the loss of power to its cooling water pump. The licensee has notified the State and local agencies. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA OPS Center, EPA EOC, FDA EOC, and Nuclear SSA via email.

  • * * UPDATE FROM MIKE HAYES TO DONG PARK AT 2252 EDT ON 04/02/2014 * * *

At 2132 CDT on April 2, 2014, the licensee terminated the Unit 2 Alert declaration. Unit 2 is stable in Mode 3 (Hot Shutdown). Unit 2 is proceeding to Mode 4 (Cold Shutdown) on shutdown cooling. The licensee notified the NRC Resident Inspector and the State emergency agencies. Notified the IRD (Gott), R3DO (Passehl), and NRR EO (McGinty). Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA OPS Center, EPA EOC, FDA EOC, and Nuclear SSA via email.

ENS 4995825 March 2014 22:44:00ClintonManual ScramNRC Region 3GE-6The plant was stable at 85 percent power when off-gas flow started lowering. The operating crew entered the loss of vacuum off-normal procedure and commenced an emergency power reduction to attempt to slow/halt the loss of vacuum while attempting various prescribed actions in the off-normal procedure. When vacuum reached 24 in. Hg, a rapid plant shutdown was performed as prescribed in the off-normal procedure. Power was at 46 percent when a rapid plant shutdown was commenced with the mode switch placed in shutdown at 1942 CDT. All control rods fully inserted on the scram, no emergency core cooling system injected or was required, no safety/relief valve(s) lifted and all systems responded as expected on the scram. The plant will remain in mode 3 with normal makeup from the feedwater system and pressure control on the turbine bypass valves with the main condenser available as a heat sink. All vital and non-vital electrical busses are powered from reserve off-site sources and no emergency diesel generators started on the scram. The cause of the loss of vacuum is under investigation. The licensee notified the NRC Resident Inspector.