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 Entered dateSiteScramRegionReactor typeEvent description
ENS 540961 June 2019 03:15:00River BendManual ScramNRC Region 4

At 2345 CDT at River Bend Station (RBS) Unit 1, a manual Reactor scram was inserted in anticipation of receiving an automatic Reactor Water Level 3 (9.7") scram due to the isolation of the 'B' Heater String with the 'A' Heater String already isolated. The 'B' heater string isolation caused loss of suction and subsequent trip of the running Feed Water Pumps 'A' and 'C'. All control rods fully inserted with no issues. Subsequently Reactor level was controlled by the Reactor Core Isolation Cooling (RCIC) system. Feed Water Pump 'C' was restored 4 minutes after the initial trip and the RCIC system secured. Currently RBS-1 is stable and is being cooled down using Turbine Bypass Valves. No radiological releases have occurred due to this event from the unit. The plant is currently under a normal shutdown electrical lineup. The licensee notified the NRC Resident Inspector.

  • * * UPDATE AT 1603 EDT ON 6/10/19 FROM ALFONSO CROEZE TO JEFF HERRERA * * *

This amended event notification is being made to provide additional information that was not included in the original notification made on 6/1/19 at 0315 EDT. This event was reportable under 10 CFR 50.72(b)(3)(iv)(A) which was not annotated or described in the original report. Forty-two minutes after the Feed Water Pump 'C' was started, the pump tripped causing a Reactor Water Level 3 (9.7") RPS actuation. Feed Water was restored five minutes later using the Feed Water Pump 'A'. The NRC Resident Inspector has been notified. Notified the R4DO (Warnick).

ENS 5409126 May 2019 09:25:00Arkansas NuclearAutomatic ScramNRC Region 4This is a 4-hour Non-Emergency 10 CFR 50.72(b)(2)(iv)(B) notification due to a Plant Protection System (PPS) actuation. Arkansas Nuclear One, Unit 2, automatically tripped from 100 percent power at 0512 CDT. The reactor automatically tripped due to 2P-32B Reactor Coolant Pump tripping as a result of grounding. No additional equipment issues were noted. All control rods fully inserted. Emergency Feedwater (EFW) actuated and was utilized to maintain Steam Generator (SG) levels. The EFW actuation meets the 8-hour Non-Emergency Immediate Notification Criteria of 10 CFR 50.72(b)(3)(iv)(A). No Primary safety valves lifted. Main Steam Safety Valves (MSSVs) did lift initially after the trip. The NRC Resident Inspector has been notified. Decay heat is being removed via the steam dump valves to the main condenser. Unit 2 is in a normal shutdown electrical lineup. Unit 1 was not affected by the transient on Unit 2. The licensee notified the State of Arkansas."
ENS 5407118 May 2019 02:09:00PilgrimManual ScramNRC Region 1

On Friday, May 17, 2019 at 2303 (EDT), with the reactor at 70 (percent) core thermal power, Pilgrim Nuclear Power Station initiated a manual reactor scram due to degrading condenser vacuum as a result of the trip of Seawater Pump B. All control rods inserted as designed. The plant is in hot shutdown. Plant safety systems responded as designed. Pressure is being controlled using the Mechanical Hydraulic Control System and Main Condenser. Reactor water level is being maintained with the feedwater and condensate system. During the manual reactor scram, the plant experienced the following isolation signals as designed:

"Group 2 Isolation: Miscellaneous containment isolation valves
Group 6 Isolation: Reactor Water Clean-up
Reactor Building Isolation Actuation

Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B), 'any event that results in actuation of the reactor protection system (RPS) when the reactor is critical...' This notification is also being made in accordance with 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...' (B)(2) 'General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs).' This event has no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The licensee will notify the Massachusetts Emergency Management Agency."

ENS 5406816 May 2019 18:07:00WaterfordAutomatic ScramNRC Region 4This is a non-emergency notification from Waterford 3. On May 16, 2019, at 1348 CDT, Waterford 3 experienced an automatic reactor trip due to Steam Generator number 1 high level, which was the result of a Main Turbine trip and subsequent reactor power cutback which had occurred at 1345 CDT. The cause of the Main Turbine trip is currently under investigation. Subsequent to the Reactor trip, Main Feedwater Isolation Valves number 1 and number 2 closed on high Steam Generator levels. Emergency Feedwater automatically actuated for Steam Generator number 2 at 1419 CDT and Steam Generator number 1 at 1425 CDT. Main Feedwater was restored to both Steam Generators by 1629 CDT. The plant entered the Emergency Operating Procedure for an uncomplicated reactor trip and is in the process of transitioning to the normal operating shutdown procedure. The plant is currently in Mode 3 and stable with Main Feedwater feeding and maintaining both Steam Generators. The NRC Senior Resident Inspector has been notified. All control rods fully inserted. Decay heat is being removed through the main condenser. The plant is in a normal shutdown electrical lineup.
ENS 5406212 May 2019 15:28:00Grand GulfManual ScramNRC Region 4

At 1039 CDT the reactor was manually (scrammed) due to a partial loss of plant service water. The loss of plant service water was caused by a loss of (balance of plant) BOP transformer 23. Reactor power was reduced in an attempt to restore pressure to plant service water. Reactor level is being maintained with condensate and feedwater. Reactor pressure is being maintained with bypass control valves. Standby Service Water A and B were manually initiated to supply cooling to Control Room A/C and (Engineered Safety Feature) ESF switchgear room coolers. The cause is under investigation. The NRC Resident Inspector has been notified. This event is being reported under 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 and also reported under 10 CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS and Standby Service Water. The plant is currently in a normal electrical lineup.

  • * * UPDATE ON 5/12/19 AT 1846 EDT FROM GERRY ELLIS TO JEFFREY WHITED * * *

This is an update to the original notification. The Drywell and Containment exceeded the technical specification (TS) temperature limits of 135 degrees F (TS Limiting Condition of Operation (LCO) 3.6.5.5) and 95 degrees F (TS LCO 3.6.1.5), respectively. An 8-hour notification is being added for any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material per 10 CFR 50.72(b)(3)(v)(C). Notified R4DO (Alexander).

ENS 5395424 March 2019 17:40:00Indian PointAutomatic ScramNRC Region 1On March 24, 2019, at 1445 EDT, Indian Point Unit 2 automatically tripped on a turbine trip due to a loss of excitation. All control rods fully inserted and plant equipment responded normally to the unit trip. This RPS (reactor protection system) actuation is reportable under 10 CFR 50.72(b)(2)(iv)(B). The auxiliary feedwater system actuated following the automatic trip as expected. This specified system actuation 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. Unit 2 is in Mode 3 at normal operating temperature and pressure. Decay heat removal is via the steam generators to the atmospheric steam dumps. No radiation was released. Indian Point Unit 3 was unaffected by this event and remains defueled in a scheduled refueling outage. A post trip investigation is in progress. The licensee has notified the NRC Resident Inspector The New York State Public Service Commission, Consolidated Edison System Operator, and New York State Independent System Operator were also notified.
ENS 5393715 March 2019 13:39:00Indian PointAutomatic ScramNRC Region 1On March 15, 2019 at 1300 EDT, Indian Point Unit 2 automatically tripped offline from mode 1 - 100% power operations. Reactor Operators verified the reactor trip and the plant is currently stable in mode 3. All automatic systems functioned as required. The auxiliary feedwater system actuated following the trip, as expected. All control rods fully inserted upon the trip, as expected. This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) and 10 CFR 50.72(b)(2)(iv)(B). The unit remains on offsite power in hot standby at normal operating temperature and pressure. Decay heat is being removed from the steam generators via the auxiliary feedwater system and the condensate steam dump valves. Unit 3 remains in mode 6 for a scheduled refueling outage. The licensee notified the NRC Resident Inspector, the local transmission company, and New York State Independent System Operator. The Indian Point Unit 2 automatic trip was caused by the trip of the main generator. The cause of the generator trip is unknown at this time.
ENS 5389423 February 2019 19:05:00Grand GulfAutomatic ScramNRC Region 4Actuation of RPS (Reactor Protection System) with the reactor critical. Reactor scram occurred at 1458 (CST) on 2/23/2019 from 100% power. The cause of the scram was due to Turbine Control Valve Fast Closure. All control rods are fully inserted. Currently reactor water level is being maintained by the Condensate Feedwater System in normal band and reactor pressure is being controlled via Main Turbine Bypass valves to the main condenser. No ECCS (Emergency Core Cooling System) initiation signals were reached and no ECCS or Diesel Generator initiation occurred. The Low-Low Set function of the Safety Relief Valves actuated upon turbine trip. This was reset when pressure was established on main turbine bypass valves. The cause of the turbine trip is still under investigation. There were no complications with scram response. The licensee notified the NRC Resident Inspector. There was no maintenance occurring on the main turbine at the time of the scram.
ENS 538199 January 2019 13:23:00PalisadesAutomatic ScramNRC Region 3At 1034 EST on January 9, 2019, with the reactor at 100% power, an automatic reactor trip was initiated. The trip occurred while Reactor Protection System testing was in progress. The trip was uncomplicated with all systems responding normally following the rip. Troubleshooting and investigation of the cause is ongoing. All full-length control rods inserted fully. Auxiliary Feedwater System actuated as designed in response to low steam generator water levels. Operations stabilized the plant in Mode 3 (hot standby). Decay heat is being removed by the turbine bypass valve. This condition has no impact to the health and safety of the public. The licensee notified the NRC Resident Inspector.
ENS 538133 January 2019 23:57:00PalisadesManual ScramNRC Region 3At 2028 (EST) on January 3, 2019, with the reactor at 85% power, the reactor was manually tripped due to cycling of Turbine Governor Valve #4. The trip was uncomplicated with all systems responding normally following the trip. Investigation of the cause of the valve cycling is ongoing. All full-length control rods inserted fully. Auxiliary Feedwater System actuated as designed in response to low steam generator water levels. Operations stabilized the plant in Mode 3 (hot standby). Decay heat is being removed by atmospheric dump valves. This condition has no impact to the health and safety of the public. The licensee notified the NRC Senior Resident Inspector. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A)."
ENS 5379318 December 2018 15:40:00Arkansas NuclearAutomatic ScramNRC Region 4On December 18, 2018 at 1126 CST, Arkansas Nuclear One, Unit 1 (ANO-1) reactor automatically tripped due to a loss of the A-1, non-vital 4160V bus. All control rods fully inserted. Loss of the A-1 bus resulted in de-energizing A-3 vital 4160V bus. Emergency Diesel Generator #1, K-4A, started automatically and is currently powering A-3 vital bus. Non-vital buses A-2, H-1, and H-2 and vital bus A-4 transferred power automatically to the Startup Transformer #1. Off-site power remains energized and available for ANO-1. The reason for loss of A-1 bus is unknown at this time. Currently, ANO-1 has stabilized in Mode 3, Hot Standby. Decay heat is being removed by the main condenser using the turbine bypass valves. The loss of the A-1, non-vital bus, is under investigation. The licensee has notified the NRC Resident Inspector and the state.
ENS 5378812 December 2018 17:29:00Grand GulfManual ScramNRC Region 4

EN Revision Text: MANUAL REACTOR SCRAM DUE TO FAILED OPEN TURBINE BYPASS VALVE At 1351 CST, the reactor was manually shutdown due to 'A' Turbine Bypass Valve opening. The Main Steam Line Isolation Valves were manually closed to facilitate reactor pressure control. Reactor level is being maintained through the use of Reactor Core Isolation Cooling System, Control Rod Drive System, and High Pressure Core Spray System. High Pressure Core Spray System was manually started to initially support reactor water level control. Reactor Pressure is being controlled through the use of the Safety Relief Valves and the Reactor Core Isolation Cooling System. The plant is stable in MODE 3. The cause of the 'A' Turbine Bypass Valve opening is under investigation at this time. The NRC Resident Inspector has been notified.

  • * * UPDATE ON 12/14/18 AT 1140 EST FROM GERRY ELLIS TO TOM KENDZIA * * *

This is an update to EN # 53788 to correct an error on the event classification block of the form. The original notification did not have the block for 8 hour notification for Specified System Actuation checked. The actuation of Reactor Core Isolation Cooling System was discussed in original notification. The licensee notified the NRC Resident Inspector. Notified R4DO (Taylor).

ENS 5373210 November 2018 04:35:00River BendAutomatic ScramNRC Region 4

At 0046 CST, River Bend Station experienced an automatic reactor scram on high reactor pressure. Initial indications are that the cause of the scram was an uncommanded closure of the #3 turbine control valve. The plant is stable with reactor water level in the normal level band of 10-51 inches being maintained with feedwater and condensate. Reactor pressure is in the prescribed band of 500-1090 psig, being maintained with turbine bypass valves and steam line drains. No injection systems were actuated either manually or automatically as a result of the event. The reactor scrammed on a Reactor Pressure High scram signal. A Reactor Level 3 signal resulted from the normal post-scram water level response. All systems responded as designed.

This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an automatic RPS actuation with the reactor critical. All control rods fully inserted. The Unit is in a normal shutdown electrical alignment. All control rods inserted properly and all systems functioned as designed. The licensee is investigating the cause of the event. The licensee notified the NRC resident inspector.

ENS 536485 October 2018 15:39:00PilgrimAutomatic ScramNRC Region 1On Friday, October 5, 2018 at 1209 hours, with the reactor at 100 percent core thermal power, Pilgrim Nuclear Power Station (PNPS) automatically tripped due to reactor water level perturbation and receipt of a low reactor water level Reactor Protection System (RPS) signal. The cause of the low reactor water level is under investigation. The plant is in hot shutdown. All other plant systems responded as designed. Pressure is being controlled using the Mechanical Hydraulic Control System and Main Condenser. Reactor water level is being maintained with the feedwater and condensate system. During the automatic reactor scram the plant experienced the following isolation signals as designed: Group 2 Isolation: Miscellaneous containment isolation valves Group 6 Isolation: Reactor Water Clean-up Reactor Building Isolation System Actuation Due to the RPS actuation while critical, this event is being reported as a four-hour, non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B), 'any event that results in actuation of the reactor protection system (RPS) when the reactor is critical.' This notification is also being made in accordance with 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 ... ' (B)(2) 'General containment isolation signals affecting containment isolation valves in more than one system.' This event has no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The licensee will notify the Massachusetts Emergency Management Agency.
ENS 5361118 September 2018 09:06:00Indian PointManual ScramNRC Region 1Due to a steam leak on the reheater line to 36C Feedwater Heater, operators initiated a manual trip of the reactor, verified the reactor trip, and closed all Main Steam Isolation Valves. The plant is currently stable in Mode 3 with the steam leak isolated. The Auxiliary Feedwater System actuated following the trip as expected. This is reportable under 10 CFR 50.72(b)(3)(iv)(A) and 10 CFR 50.72(b)(2)(iv)(B). The unit remains on offsite power in Hot Standby at normal operating temperature and pressure. Decay heat is being removed from the steam generators via the Auxiliary Feedwater System and atmospheric steam dumps. Unit 2 was unaffected and remains at 100 percent power. The licensee notified the NRC Resident Inspector, the State of New York, and the local transmission company.
ENS 5360814 September 2018 21:09:00Grand GulfManual ScramNRC Region 4At 1644 (CDT) a manual reactor scram was inserted by placing the Reactor Mode Switch to Shutdown. At 1643 (CDT) the Condensate Booster Pump A tripped on low suction pressure. At 1644 (CDT) the Reactor Feed Pump A tripped on low suction pressure. A Recirculation Flow Control Valve runback occurred as designed. Reactor Water level was approaching the Automatic Low Water Level 3 (11.4 inches) scram set point and manual actions were taken by placing the Mode Switch to Shutdown before the low level set point was reached. All systems responded as expected following the manual scram. The plant is stable in mode 3. This event is being reported under 10CFR 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 Senior Resident Inspector has been notified. All control rods fully inserted, and decay heat is being removed through the turbine bypass valves to the main condenser. The licensee is investigating the cause of the event.
ENS 5345916 June 2018 15:56:00Arkansas NuclearManual ScramNRC Region 4At 1121 CDT on June 16, 2018, Arkansas Nuclear One, Unit 1 (ANO-1) performed a manual reactor trip due to a Turbine Bypass valve failing open on reactor startup. At the time, ANO-1 was in Mode 2 at approximately 2 percent power. The failed Turbine Bypass valve resulted in an overcooling event and the Overcooling Emergency Operating Procedure (EOP) was entered. Main Steam Line Isolation (MSLI) automatic actuation occurred on 2 of the 4 channels of Emergency Feedwater Initiation and Control during the overcooling event in the 'B' Steam Generator. The remaining channels of MSLI were manually actuated by the control room staff from the control room. Overcooling was terminated after the closure of the Main Steam Isolation Valve (MSIV) and reactor coolant parameters were stabilized as directed by the Overcooling EOP. Additionally, Gland Sealing Steam was lost to the main turbine due to the closure of the 'B' Steam Generator MSIV and Loss of Condenser Vacuum Abnormal Operating Procedure was entered. This is a 4-hour non-emergency 10 CFR 50.72 (b)(2)(iv)(B) notification due to a Reactor Protection System actuation (scram) and an 8-hour non-emergency 10 CFR 50.72 (b)(3)(iv)(A) notification for safety system actuation." All control rods fully inserted into the core during the trip. Heat removal is via the Atmospheric Dump Control valves to atmosphere. The NRC Resident Inspector has been notified. The licensee also notified the State of Arkansas.
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 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 531921 February 2018 14:23:00River BendManual ScramNRC Region 4GE-6

At 1057 CST on February 1, 2018 with the unit in Mode 1 at approximately 27% power, a manual actuation of the Reactor Protection System (RPS) was initiated due to an unexpected trip of the B Recirc Pump with A Recirc Pump in fast speed. B Recirc Pump tripped during transfer from slow to fast speed resulting in single loop operation. Operators were unable to reconcile differing indications of core flow. This resulted in a conservative decision to initiate a manual scram. The cause of the B Recirc Pump trip and the apparent issues with core flow indication are under investigation. The plant is currently stable in Mode 3. The plant response to the scram was as expected. All control rods (fully) inserted as expected; the feedwater system is maintaining reactor vessel water level in the normal control band and reactor pressure is being maintained with steam line drains and main turbine bypass valves. The NRC Senior Resident (Inspector) has been notified.

  • * * RETRACTION AT 1015 EDT ON 03/22/2018 FROM DAVID DABADIE TO OSSY FONT * * *

This event was initially reported under 10 CFR 72(b)(2)(iv)(B) as a manual actuation of the RPS due to an unexpected trip of the B Reactor Recirculation Pump with the A Reactor Recirculation Pump running in fast speed (Single Loop Operations). Operations was unable to reconcile differing indications of core flow and made the conservative decision to perform a planned shutdown in accordance with normal operating procedures. Therefore, this event 'resulted from and was part of a pre-planned sequence during testing or reactor operation' as specified in 10 CFR 50.72(b)(2)(iv)(B), 10 CFR 50.73(a)(2)(iv)(A) and NUREG-1022 Section 3.2.6. Consequently, this event is not reportable as an actuation of RPS. The NRC Resident Inspector has been notified. R4DO (Groom) has been notified.

ENS 5318830 January 2018 21:56:00Grand GulfManual ScramNRC Region 4GE-6On 1/30/2018 at 1750 (CST), the Reactor Pressure Control Malfunctions ONEP (Off Normal Event Procedure) was entered due to main turbine load oscillations of approximately 30 MWe peak to peak. At 1822 (CST), a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown due to continued main turbine load oscillations. Reactor SCRAM ONEP, Turbine Trip ONEP, and EP-2 were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 933 psig using main turbine bypass valves. Reactor Water Level 3 (11.4 inches) was reached which is the setpoint for Group 2 (RHR to Radwaste Isolation) and Group 3 (Shutdown Cooling Isolation). No valve isolated in these systems due to all isolation valves in these groups being in their normally closed position. The lowest Reactor Water level reached was -36 inches wide range. No other safety system actuations occurred and all systems performed as designed. That event is being reported under 10CFR 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 and also reported under 10CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS. The MSIVs are open with decay heat being removed via steam to the main condenser using the bypass valves. Off site power is stable, and the plant is in a normal shutdown electrical lineup. RCIC (Reactor Core Isolation Cooling) was out of service for maintenance, and the reactor water level did not reach the system activation level. The cause of the main turbine load oscillations being investigated. The licensee notified the NRC Resident Inspector.
ENS 531474 January 2018 17:57:00PilgrimManual ScramNRC Region 1GE-3On January 4, 2018, at 1410 hours EST, with the reactor at approximately 100 percent power and steady state conditions, the winter storm across the Northeast caused the loss of offsite 345 kV Line 342. Reactor power was reduced to approximately 81 percent and a procedurally required manual reactor scram was initiated. All control rods fully inserted. As a result of the reactor scram, indicated reactor water level decreased, as expected, to less than +12 inches resulting in automatic actuation of the Primary Containment Isolation Systems for Group II - Primary Containment Isolation and Reactor Building Isolation System, and Group VI - Reactor Water Cleanup System. Reactor Water Level was restored to the normal operating band. The Primary Containment Isolation Systems have been reset. The Reactor Protection System signal has been reset. Following the reactor scram, the non-safety related Control Rod Drive Pump "B" tripped on low suction pressure. Control Rod Drive Pump "A" was placed in service. All other systems operated as expected, in accordance with design. This event is reportable per the requirements of Title 10, Code of Federal Regulations (CFR) 50.72 (b)(2)(iv)(B) - "RPS Actuation" and 10 CFR 50.72 (b)(3)(iv)(A) - "Specified System Actuation. This event had no impact on the health and/or safety of the public. The NRC Resident Inspector has been notified. The main steam isolation valves are open with decay heat being removed via steam to the main condenser. Offsite power is still available from 345kV line 355. As a contingency, emergency diesel generators are running and powering safety busses per licensee procedure. The licensee notified the Commonwealth of Massachusetts. The licensee will be notifying the town of Plymouth as part of their local notifications. The licensee will be issuing a press release.
ENS 5309025 November 2017 06:02:00Grand GulfManual ScramNRC Region 4GE-6

At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 (CST), with reactor power just above the point of adding heat, IRM (Intermediate Range Monitor) channels A, C, and D received a spurious upscale trip signal which immediately cleared. Upon investigation, operability of RPS (Reactor Protection System) scram function for Intermediate Range Detectors was placed in question. This event is being reported under 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 licensee notified the NRC Resident Inspector.

  • * * UPDATE ON NOVEMBER 26, 2017, AT 1850 FROM GRAND GULF TO MICHAEL BLOODGOOD * * *

At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 (CST), with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event is being reported under 10CFR 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. This Revised Statement to Event Notification # 53090 is being made to make it clear that only four IRM channels (A, C, D, G) were Inoperable and that the IRM RPS SCRAM function was still available from the four remaining Operable IRM channels (B, E, F, and H). The licensee notified the NRC Resident Inspector. Notified R4DO (O'Keefe)

  • * * RETRACTION ON 01/16/2018 AT 1629 EST FROM JASON COMFORT TO DAVID AIRD * * *

On 11/25/17, at 0149 (CST), with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event was initially being reported under 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. After the trip alarms were received, the Operators spent approximately twenty minutes investigating possible causes and implications, and consulted with Reactor Engineering and the Shift Technical Advisor. The investigation showed that the plant was stable and the upscale IRM alarms were spurious. A review of plant technical specifications by the operators determined that a plant shutdown was not required. After further discussions, Operations concluded that a shutdown to allow further investigation of the issue was the prudent course of action. Prior to shutting down, Operations spent approximately twenty minutes reviewing procedures, notifying personnel to exit containment, and conducting a brief. The shutdown was then conducted by inserting a manual reactor scram by placing the reactor mode switch in SHUTDOWN. This was initially reported under 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the RPS. Based on the sequence of events, and Operator actions in conducting the shutdown, the event is considered 'part of a pre-planned sequence during testing or reactor operation' as specified in 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.73(a)(2)(iv)(A). In accordance with NUREG-1022, Section 3.2.6, the event is not reportable as an actuation of RPS. The licensee notified the NRC Resident Inspector. Notified R4DO (Taylor).

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 5291518 August 2017 23:41:00River BendAutomatic ScramNRC Region 4GE-6At 2055 CDT on August 18, 2017, an automatic actuation of the reactor protection system occurred while the plant was operating at 100 percent power. No plant parameters requiring the actuation of the emergency diesel generators or the emergency core cooling system were exceeded. The main feedwater system remained in service following the scram to maintain reactor water level, and the main condenser remained available as the normal heat sink. The scram occurred after a planned swap of the main feedwater master controller channels in preparation for scheduled surveillance testing. When the channel swap was actuated, the feedwater regulating valves moved to the fully open position. The scram signal originated in the high-flux detection function of the average power range monitors, apparently from the rapid increase in feedwater flow. The cause of the apparent feedwater controller malfunction is under investigation. The NRC Resident Inspector has been notified. No safety relief valves opened. Decay heat is being removed via steam to the main condenser using the bypass valves and steam drains. The licensee intends to go to Cold Shutdown to investigate the malfunction.
ENS 5286317 July 2017 17:37:00WaterfordAutomatic ScramNRC Region 4CE

During a rain and lightning storm, plant operators observed arcing from the main transformer bus duct and notified the control room. The decision was made to trip the main generator which resulted in an automatic reactor trip. The plant entered EAL SU.1 as a result of the loss of offsite power for greater than fifteen minutes. Plant safety busses are being supplied by both emergency diesel generators while the licensee inspects the electrical system to determine any damage prior to bringing offsite power back into the facility. Offsite power is available to the facility. No offsite assistance was requested by the licensee. During the trip, all rods inserted into the core. Decay heat is being removed via the atmospheric dump valves with emergency feedwater supplying the steam generators. The main steam isolation valves were manually closed to protect the main condenser. There were no safeties or relief valves that actuated during the plant transient. There is no known primary-to-secondary leakage. Reactor cooling is via natural circulation. All safety equipment is available for the safe shutdown of the plant. The licensee has notified the NRC Resident Inspector, Louisiana Department of Environmental Quality and the local Parish emergency management agencies. Notified DHS SWO, FEMA, DHS NICC, FEMA National Watch Center (email) and Nuclear SSA (email).

  • * * UPDATE ON 7/17/17 AT 2007 EDT FROM MARIA ZAMBER TO DONG PARK * * *

This notification is also made under 10 CFR 50.72(b)(3)(v)(D). This is a non-emergency notification from Waterford 3. On July 17, 2017 at 1606 CDT, the reactor automatically tripped due to a loss of Forced Circulation, which was the result of Loss of Offsite Power (LOOP) to the electrical (safety and non-safety) buses. Both 'A' and 'B' trains of Emergency Diesel Generators (EDGs) started as designed to reenergize the 'A' and 'B' safety buses. The LOOP caused a loss of feedwater pumps, resulting in an automatic actuation of the Emergency Feedwater (EFW) system. Prior to the reactor trip, at 1600 CDT, personnel noticed the isophase bus duct to main transformer 'B' glowing orange due to an unknown reason. Due to this, the main turbine was manually tripped at 1606 CDT. Following the turbine trip, the electrical (safety and non-safety) buses did not transfer to the startup transformers as expected due to an unknown reason. The plant entered the Emergency Operating Procedure for LOOP/Loss of Forced Circulation Recovery. At 1617 CDT, an Unusual Event was declared due to Initiating Condition (IC) SU1 - Loss of all offsite AC power to safety buses (greater than) 15 minutes. All safety systems responded as expected. The plant is currently in mode 3 and stable with the EDGs supplying both safety buses and with EFW feeding and maintaining both steam generators. Offsite power is in the process of being restored. The licensee has notified the NRC Resident Inspector, Louisiana Department of Environmental Quality and the local Parish emergency management agencies.

  • * * UPDATE FROM ADAM TAMPLAIN TO HOWIE CROUCH AT 2203 EDT ON 7/17/17 * * *

The licensee terminated the Notification of Unusual Event at 2056 CDT. The basis for terminating was that offsite power was restored to the safety busses. The licensee has notified Louisiana Department of Environmental Quality, St. John and St. Charles Parishes, Louisiana Homeland Security Emergency Preparedness, and will be notifying the NRC Resident Inspector. Notified IRD (Stapleton), NRR (King), R4DO (Hipschman), DHS SWO, FEMA, DHS NICC, FEMA National Watch Center (email) and Nuclear SSA (email).

  • * * UPDATE FROM SCOTT MEIKLEJOHN TO HOWIE CROUCH AT 1724 EDT ON 7/19/17 * * *

This update is being reported under 10 CFR 50.72(b)(3)(v)(B). During the event discussed in EN# 52863, at 1642 CDT (on July 17, 2017), Condensate Storage Pool (CSP) level lowered to less than 92% resulting in entry to Technical Specification (TS) 3.7.1.3. Level in the CSP was lowered due to feeding from both Steam Generators with EFW. Normal makeup to the CSP was temporarily unavailable due to the LOOP. Filling the CSP commenced at 1815 CDT (on July 17, 2017), and TS 3.7.1.3 was exited on July 18, 2017 at 0039 CDT. The licensee notified the NRC Resident Inspector. Notified R4DO (Hipschman).

  • * * UPDATE FROM SCOTT MEIKLEJOHN TO HOWIE CROUCH AT 1233 EDT ON 9/14/17 * * *

Waterford 3 is retracting a follow up notification made on July 19, 2017 for EN# 52863, concerning the loss of safety function associated with the Condensate Storage Pool (CSP) per 10 CFR 50.72(b)(3)(v)(B). The Condensate Storage Pool was performing its required safety function by providing inventory to the Emergency Feed Water pumps when the required Tech Spec level (T.S. 3.7.1.3) dropped below 92%. The Technical Specification was entered at 1624 (CDT) on July 17, 2017 and exited after filling at 0039 on July 18, 2017. The total allowed outage time allowed by Tech Spec 3.7.1.3 is 10 hours to be in Hot Shutdown if not restored. The Condensate Storage Pool level was restored to greater than 92% prior to exceeding the allowed outage time. Based on level being restored and the Condensate Storage Pool performing its required safety function, 10 CFR 50.72(b)(3)(v)(B) does not apply. Prior to the automatic reactor trip, Condensate Storage Pool level was greater than 92%. The NRC Resident Inspector has been notified of the retraction. Notified R4DO (Groom).

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 5282523 June 2017 23:58:00River BendAutomatic ScramNRC Region 4GE-6While performing a scheduled generator voltage regulator test, River Bend Station experienced an automatic scram when the main generator tripped. It is unknown at this time why the main generator tripped. There were no equipment issues that materially impacted post scram operator response. The intention at this time is to go to cold shutdown while the cause of the trip is investigated. All rods inserted during the scram. Reactor water level is being maintained via normal feedwater with decay heat being removed via turbine bypass valves to the main condenser. The electrical grid is stable and supplying plant loads via the normal shutdown electrical lineup. The licensee has notified the NRC Resident Inspector.
ENS 5271026 April 2017 14:49:00Arkansas NuclearAutomatic ScramNRC Region 4B&W-L-LP
CE
At 1004 CDT, Arkansas Nuclear One, Unit 1 (ANO-1) reactor automatically tripped due to the partial loss of offsite power. At the time of the trip, the site was in a Tornado Warning and a Severe Thunderstorm Warning. The Emergency Feedwater (EFW) system auto-actuated due to the loss of main feedwater pumps and the loss of the Reactor Coolant pumps. Both Emergency Diesel Generators started as expected with only one loading as expected. All control rods fully inserted. Currently, ANO-1 has stabilized in Hot Standby via natural circulation. ANO-1 also lost Spent Fuel Pool cooling for approximately 69 minutes. The temperature of the spent fuel pool at the beginning of the event was approximately 102 (degrees) F. The spent fuel pool saw a heatup of 1 (degree) F during the loss of spent fuel pool cooling. The Spent Fuel Pool cooling has been restored. ANO-2 is currently in a refueling outage with all fuel in the spent fuel pool. ANO-2 completed a full core off load to the spent fuel pool and this was completed on April 12, 2017. Spent Fuel Pool cooling was lost for approximately 10 minutes. The Spent Fuel Pool temperature was 91 (degrees) F prior to the event. No heat up of the pool was identified during the event. Cooling has subsequently been restored. The #1 Emergency Diesel Generator auto-started as designed but did not supply the safety bus due to availability of offsite power. No radiological releases have occurred from either unit due to this event. The licensee has notified the NRC Resident Inspector.
ENS 526634 April 2017 06:57:00Grand GulfManual ScramNRC Region 4GE-6At 0010 (CDT), 04/04/2017, the reactor was manually scrammed from approximately 75 (percent) core thermal power due Condensate Storage tank level lowering to 24 feet. All control rods fully inserted and all systems actuated and operated as designed. No safety relief valves actuated. Reactor level and pressure are currently being controlled within normal bands. RCIC (reactor core isolation cooling) was manually initiated for level control. This event is reportable under 10CFR50.72(b)(2)(iv)(B) for the reactor trip and 50.72(b)(3)(iv)(A) for the manual start of the reactor core isolation cooling system. The cause of lowering level was a condensate pipe leak. Decay heat is being removed via steam dumps to the condenser. The electrical grid is stable and supplying plant loads. The licensee has notified the NRC Resident Inspector.
ENS 5260210 March 2017 11:41:00River BendManual ScramNRC Region 4GE-6At 0714 CST on March 10, 2017, with the unit in Mode 1 at approximately 17% power, a manual actuation of the reactor protection system (RPS) was initiated due to rising reactor pressure caused by the closure of the Main Turbine Control Valves (MTCV's). The cause of the closure of the MTCV's is under investigation. The unit is currently stable in Mode 3. All control rods inserted as expected; water level control is stable in the normal control band and reactor pressure is being maintained with steam line drains (aligned to the main condenser). The NRC Senior Resident Inspector has been notified.
ENS 522236 September 2016 11:24:00PilgrimManual ScramNRC Region 1GE-3On Tuesday, September 6, 2016 at 0827 (EDT), with the reactor at 91% core thermal power (CTP), Pilgrim Nuclear Power Station (PNPS) operators initiated a manual reactor scram due to high reactor water level resulting from feedwater level control oscillation. Other than the feedwater level control oscillations, all other plant systems responded as designed. Plant cooldown is in progress using the High Pressure Coolant Injection System in the pressure control mode. The plant is in hot shutdown. The cause of the feed water level control oscillations is under investigation. This event has no impact on the health and safety of the public. Subsequent to the manual reactor scram the plant experienced the following isolation signals: Group 1 Isolation: Main Steam Isolation Valves Group 2 Isolation: Miscellaneous containment isolation valves Group 6 Isolation: Reactor Water Clean-up Reactor Building (Ventilation) Isolation Actuation The licensee has notified the NRC Senior Resident Inspector. This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), 'any event that results in actuation of the reactor protection system (RPS) when the reactor is critical...'. This notification is also being made in accordance with 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...' (B)(2) 'General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs).' All rods were inserted. The plant is stable with normal off-site power line-up. The licensee will notify the Commonwealth of Massachusetts.
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 5204425 June 2016 18:30:00Grand GulfAutomatic ScramNRC Region 4GE-6At 1407 (CDT), during power ascension to 100 percent, turbine control valves closed unexpectedly causing reactor protection trip signals that in turn caused a reactor scram. Reactor scram, turbine trip ONEPs (Off Normal Event Procedure), and EP2 (Emergency Procedure for Level Control) were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 935 psig using bypass valves. No other safety system actuations occurred and all systems performed as designed. All control rods inserted. Reactor level is maintained by feedwater. Normal electrical shutdown configuration is through offsite electrical power sources. The Safety Relief Valves lifted, then closed. The plant is stable at normal level and pressure and remains in Mode 3. The event is under licensee investigation. The licensee notified the NRC Resident Inspector.
ENS 5201217 June 2016 06:21:00Grand GulfAutomatic ScramNRC Region 4GE-6During planned stop and control valve testing, two main turbine high pressure stop valves closed instead of the expected one (stop valve 'B'). This caused the main turbine control valves, power, reactor pressure to swing and a division 2 half SCRAM. Control rods were inserted to reduce power and the power swings. At 0257 (CDT) the reactor automatically SCRAMMED. Reactor SCRAM, Turbine Trip (procedures) ONEPs and EP-2 were entered. Reactor water level was stabilized at 34 inches narrow range on startup level control and reactor pressure stabilized at 884 psig using main turbine bypass valves. No other safety related systems actuated and all systems performed as expected. The plant is in its normal shutdown electrical lineup using normal feedwater and turbine bypass valves for decay heat removal. Reactor pressure is slowly trending down. The licensee is investigating the cause of the second stop valve shutting. The licensee notified the NRC Resident Inspector.
ENS 516449 January 2016 07:04:00River BendAutomatic ScramNRC Region 4GE-6On 1/9/16 at 0237 (CST), River Bend Station sustained a reactor scram during a lightning storm. An electrical transient occurred resulting in a full main steam isolation (MSIV) (Group 6) and a Division II Balance of Plant isolation signal. During the scram, level 8 occurred immediately which tripped the feed pumps. A level 3 signal occurred also during the scram. Subsequent level 3 was received three times due to isolated vessel level control. The plant was stabilized and all spurious isolation signals reset, then the MSIVs were restored. The plant is now stable in Mode 3 and plant walkdowns are occurring to assess the transient. During the scram, all rods inserted into the core. The plant was initially cooled down using safety relief valves. Offsite power is available and the plant is in its normal shutdown electrical lineup. The licensee has notified the NRC Resident Inspector.
ENS 5160715 December 2015 10:24:00Arkansas NuclearManual ScramNRC Region 4B&W-L-LPThis is a 4-hour Non-Emergency 10 CFR 50.72(b)(2)(iv)(B) notification due to a Reactor Protection System (RPS) actuation. Arkansas Nuclear One, Unit 1, was manually tripped from 43 percent power at 0544 CST. The reactor was manually tripped due to operator judgement during control issues with the Integrated Control System (ICS) during a planned downpower for Electro-Hydraulic Control (EHC) system maintenance. CV-2672 B, low load control valve, failed to close. Subsequently, CV-2674 B, low load block valve, began to close and caused a loss of feed to E-24B Steam Generator. No additional equipment issues were noted. All control rods fully inserted. Emergency Feedwater (EFW) actuated and was utilized to maintain Steam Generator (SG) levels. This (EFW actuation) meets the 8 hour Non-Emergency Immediate Notification Criteria ((10CFR50.72(b)(3)(iv)(A)). No Primary safety valves lifted. Main Steam Safety Valves (MSSVs) did lift initially after the trip. The NRC Resident (Inspector) has been notified. Decay heat is being removed via the steam dump valves to the main condenser. Unit 1 is in a normal shutdown electrical lineup. Unit 2 was not affected by the transient on Unit 1. The licensee notified the State of Arkansas.
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 5156827 November 2015 09:23:00River BendAutomatic ScramNRC Region 4GE-6At 0431 CST on November 27, 2015, an automatic reactor scram occurred following the trip of the main generator. The generator trip was apparently caused by a partial loss of offsite power, which resulted from a differential ground on the north bus of the local 230 kV switchyard. The ground signal caused the reserve station service line no. 1 to de-energize, which tripped the Division 1 offsite power source to station, as well as the main generator. The plant responded as designed as follows: The Division 1 emergency diesel generator started and tied to the bus restoring Division 1 emergency power. The Division 3 emergency diesel generator started and tied to the bus, restoring power on the Division 3 switchgear. The reactor protection system tripped as designed. Reactor water level was controlled normally with condensate and feed water. A level 3 reactor water level scram signal occurred as expected, and RPV (Reactor Pressure Vessel) water level was restored to normal level band. Reactor pressure was controlled by the bypass valve system, and a normal cool down was initiated. The reactor is being taken to cold shutdown pending an investigation of the event. The loss of power also resulted in a partial loss of normal service water cooling to the plant, and emergency service water cooling automatically initiated per design. At the time of event, the reactor protection system was aligned to the backup power supply, which was momentarily lost. This resulted in multiple system isolations including reactor water clean up, and outboard balance of plant isolations. These isolations were initiated due to loss of offsite power, and all responded as designed. The isolation resulted in a loss of the running decay heat removal pump for the spent fuel pool. The standby pump is available for service and being aligned for service. The plant is currently stable in hot shutdown. Transmission and distribution personnel are currently investigating the ground in the 230 kV switchyard. All control rods inserted. The licensee has notified the NRC Resident Inspector.
ENS 514474 October 2015 03:51:00WaterfordAutomatic ScramNRC Region 4CEAt 2307 CDT Waterford 3 experienced an automatic reactor trip and all Control Element Assemblies (CEAs) inserted into the core. The cause of the automatic reactor trip is currently under investigation. The plant is currently in Mode 3 (Hot Standby) and stable with Main Feedwater feeding and maintaining both Steam Generators. Main Feedwater Pump 'A' tripped subsequent to the reactor trip. Emergency Feedwater actuated following the plant trip as expected, but was not required to maintain Steam Generator level. The plant entered the Emergency Operating Procedure for an uncomplicated reactor trip and has now transitioned to the normal operating shutdown procedure. Unit 3 is in a normal post trip electrical lineup. The Main Condenser is in-service removing decay heat.. The licensee informed the NRC Resident Inspector.
ENS 5139716 September 2015 03:59:00PalisadesAutomatic ScramNRC Region 3CEAt 0117 (EDT) on 9/16/2015 a reactor trip occurred (4-hr non-emergency). The plant was at approximately 85% power performing a coastdown in preparation for a refueling outage when a Digital Electro-Hydraulic (DEH) alarm was received in the control room. Shortly following receipt of the alarm the turbine tripped. This resulted in an RPS actuation and a reactor trip on Loss of Load. The crew entered EOP-1 Standard Post Trip Actions and completed all required actions. The crew subsequently entered EOP-2 Reactor Trip Recovery. All full-length control rods inserted fully. Auxiliary Feedwater System actuated in response to low steam generator water levels (8-hr non-emergency). Steam generator water levels are in progress of being returned to normal operating levels. No known primary to secondary leakage. Atmospheric Steam Dump Valves lifted after the trip and subsequently reseated. The plant is currently stable in Mode 3 at NOP/NOT being maintained by the Turbine Bypass Valve. Initial investigation into the cause of the turbine trip appears to be from a DEH power supply failure. The NRC Resident Inspector was notified of the reactor trip at 0139 on 9/16/2015.
ENS 5133822 August 2015 20:14:00PilgrimAutomatic ScramNRC Region 1GE-3

On Saturday, August 22, 2015, at 1628 (EDT), with the reactor at 100% core thermal power (CTP) the Pilgrim Nuclear Power Station (PNPS) experienced an automatic reactor scram signal due to the rapid closure of one main steam isolation valve (MSIV). Other than the MSIV all other plant systems responded as designed. Plant cooldown is in progress using steam bypass to the main condenser. The plant is in hot shutdown. The cause of the MSIV closure is still under investigation. This event has no impact on the health and safety of the public. The licensee has notified the NRC Senior Resident Inspector. This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), 'Any event that results in actuation of the reactor protection system (RPS) when the reactor is critical'. Subsequent to the reactor scram the plant experienced the following isolation signals:

    -  Group 2 Isolation: Miscellaneous containment isolation valves
    -  Group 6 Isolation: Reactor Water Clean-up
    -  Reactor Building Isolation Actuation

This notification is also being made in accordance with 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' (B)(2) 'General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs).' Plant response was considered normal and the plant is in a stable shutdown / cooldown condition. The license will be notifying the Commonwealth of Massachusetts.

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 511163 June 2015 21:36:00WaterfordManual Scram
Automatic Scram
NRC Region 4CE

This is a non-emergency notification from Waterford 3. At 1705 (CDT) the reactor was manually tripped in anticipation of an automatic trip due to loss of main feedwater pump 'A'. The plant is currently in mode 3 and stable with emergency feedwater feeding and maintaining both steam generators due to an automatic emergency feed actuation signal. During the trip, the 'B' electrical safety and non safety busses did not automatically transfer from the unit auxiliary transformer to the startup transformer causing a loss of off-site power to the 'B' electrical busses. This resulted in a loss of main feedwater pump 'B'. The 'B' emergency diesel generator started as designed and reenergized the 'B' safety related buses. The plant entered the emergency operating procedure for loss of main feedwater. Off-site power has been restored to the 'B' safety and non safety busses, and the emergency diesel generator 'B' is secured.

All control rods fully inserted into the core following the trip.  Decay heat is being removed by the main condenser using the turbine bypass valves.  The electric plant is in a normal shutdown lineup.  

The licensee has notified the NRC Resident Inspector.

ENS 511122 June 2015 02:00:00River BendAutomatic ScramNRC Region 4GE-6

At 2111 (CDT) River Bend Nuclear Station sustained an Automatic Reactor Scram due to low Reactor Water Level (Level 3). The plant is currently stable, with level being maintained in a normal band of 10 - 51 inches with Condensate and Feedwater. Reactor Pressure is in the prescribed band of 500-1090 psig. The plant is in Mode 3, Hot Shutdown, and will remain in Mode 3 until investigation of the scram is complete. The transient began with a trip of Reactor Feed Pump 'A', followed by a Reactor Scram and a trip of Reactor Feed Pump 'C'. Reactor water level was recovered with Reactor Feed Pump 'B' to a normal post scram level band. There was a problem noted with the Reactor Feedwater Master Level Controller; this was mitigated by the Operator placing the controller to manual. There was no subsequent Level transient. Reactor Pressure was stabilized in normal pressure band with Turbine bypass valves. During the transient, a Reactor Recirculating Flow Control Valve Runback was not received as expected. Reactor Recirculating Pump 'A' responded as expected to transient (switching to low pump speed), Reactor Recirculating Pump 'B' tripped during transient. A Level 3 isolation signal was received, all expected isolations occurred. The cause of the transient is currently under investigation. The reactor is stable in Mode 3 with decay heat being removed via turbine bypass valves, and a normal electrical line up. The NRC Resident Inspector has been notified.

  • * * UPDATE FROM JACK MCCOY TO HOWIE CROUCH AT 0712 EDT ON 6/2/15 * * *

At 2231 on 6/1/15, Reactor Water Cleanup System isolated on High Reactor Water Cleanup System Heat Exchanger room temperature due to loss of Turbine Building chill water during the initial transient. All Reactor Water Cleanup System Valves isolated as expected. Reactor Water Cleanup was the only system affected by this isolation signal. The licensee has notified the NRC Resident Inspector. Notified R4DO (Whitten).

ENS 5108722 May 2015 13:36:00PilgrimManual ScramNRC Region 1GE-3

On Friday, May 22, 2015 at 1002 EDT, with the Reactor Mode Select Switch in the Start-Up position and the reactor at approximately 3 percent core thermal power, while returning to power from Refueling Outage Number 20, a manual reactor scram was inserted due to degrading main condenser vacuum. The cause of the degraded vacuum is currently under investigation. Following the reactor scram, all rods were verified to be fully inserted and no Emergency Operating Procedure entry conditions existed. All plant systems responded as designed. Currently reactor pressure is being maintained at 400 psig with the Mechanical Hydraulic Control System (turbine by-pass valves). Reactor water level is being maintained in normal bands with the Condensate and Feedwater System. Off-site power is being supplied to the station by the Startup Transformer (normal power supply for shutdown operations). This event had no impact on the health and/or safety of the public. The NRC Resident Inspector is on-site and has been notified. The licensee has notified the Massachusetts Emergency Management Agency. The licensee will be issuing a press release.

  • * * UPDATE FROM EVERETT PERKINS TO DONALD NORWOOD AT 1110 EDT ON 5/24/2015 * * *

The following was provided by the licensee as clarifying information to the first paragraph of the original event notification: As a conservative measure, the operating crew had previously started reducing power from 20 percent core thermal power when it was first noticed that main condenser vacuum was degrading. This was well before any low condenser vacuum alarms were received. During the shutdown, after already securing the main turbine, the operating crew established benchmark values for degrading condenser vacuum for a normal plant shutdown and for a manual reactor scram should vacuum continue to decline to preclude an automatic scram. The licensee notified the NRC Resident Inspector. Notified R1DO (Dwyer).

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 5100322 April 2015 14:18:00River BendAutomatic ScramNRC Region 4GE-6On February 24, 2015, at approximately 1702 CDT, while the plant was in cold shutdown, power was lost on the Division 1 reactor protection system (RPS) bus. This event resulted in the automatic closure of the Division 1 primary containment isolation valves in the residual heat removal (RHR) and reactor water cleanup systems. Additionally, the primary containment atmospheric monitoring system automatically actuated, and ventilation systems in the fuel building, auxiliary building, and control building shifted to emergency mode. The closure of the isolation valves in the residual heat removal system caused an automatic trip of the 'A' RHR pump, which had been in the shutdown cooling alignment. The equipment response to the isolation signal was as expected. This event is being reported in accordance with 10 CFR 50.73(a)(1) as an invalid actuation of the Division 1 primary containment isolation system. The isolation was promptly diagnosed as having resulted from a trip of the output breaker of the RPS motor generator (MG) set 'A,' and not from a valid signal. Operators implemented the appropriate response procedures to align power to the bus via the alternate source, and began restoring the affected systems. The 'A' RHR pump was re-started within twelve minutes, during which time coolant temperature increased approximately seven degrees to a maximum of approximately 100F. Other affected systems were restored over the next few hours. The causal analysis concluded that the MG set output breaker tripped due to an overly conservative setpoint on the overvoltage trip relay. The low trip setpoint was a latent condition that had existed since the output voltage was raised in 1988 at the recommendation of the vendor, but at which time the trip setpoint was not changed. To correct this condition, the MG overvoltage trip setpoint was raised to restore adequate operating margin to the normal MG output voltage. At the time of the event, the plant was in MODE 5 with the reactor cavity flooded to greater than 23 feet above the vessel flange. The shutdown cooling system was promptly restored to service. This event was of minimal safety significance to the health and safety of employees and the public. The licensee has notified the NRC Resident Inspector.
ENS 5077127 January 2015 16:56:00PilgrimAutomatic ScramNRC Region 1GE-3On Tuesday, January 27, 2015, at 0948 EST, with the Reactor Mode Select Switch (RMSS) in the Shutdown position and Pilgrim Nuclear Power Station (PNPS) at 0% core thermal power, the High Pressure Coolant Injection (HPCI) system was isolated by the main control room operating crew and declared INOPERABLE. HPCI had been in service for reactor pressure control following the automatic reactor scram experienced during winter storm 'Juno' reported in EN# 50769. It appears there was a malfunction of the HPCI turbine gland seal condenser blower or associated condensate pump. Reactor pressure control was transitioned to the safety relief valves and the reactor cooldown was continued. The plant is stable. The Emergency Diesel Generators are powering the safety related 4KV buses and reactor water level is being maintained by the Reactor Core Isolation Cooling (RCIC) system. HPCI is required to be OPERABLE in accordance with Technical Specification 3.5.C.1. Since HPCI is a single train system, the INOPERABILITY is reportable in accordance with 10CFR50.72(b)(3)(v)(D). The cause of the HPCI malfunction is not known at this time and troubleshooting continues. This event had no impact on the health and/or safety of the public. The USNRC Senior Resident Inspector has been notified. Shutdown cooling is in service.