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Start date | Reporting criterion | Title | Event description | System | LER | |
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ENS 57004 | 4 March 2024 00:42:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram Due to Main Turbine Trip on LOW Condenser Vacuum | The following information was provided by the licensee via email: On 3/3/24 at 1942 EST, while performing a plant shutdown in preparation for a refuel outage, Nine Mile Point Unit 2 experienced a reactor scram due to a main turbine trip on low condenser vacuum. The plant was at approximately 55 percent power at the time of the reactor scram. Additionally, following the scram a low RPV (reactor pressure vessel) level scram and containment isolation signal on level 3 was received, as expected. The containment isolation signal impacted RHR (residual heat removal) shutdown cooling, RHR letdown to radwaste, and RHR sampling. All impacted valves were closed at the time the isolation occurred. All control rods were fully inserted. Plant response was as expected. Post scram, the main turbine bypass valves are being used to control decay heat, and normal post scram level control is via the feed / condensate system. This is being report under 10 CFR 50.72(b)(2)(iv)(B), 'RPS Actuation', and 10 CFR 50.72(b)(3)(iv)(A), 'Specified System Actuation'. Unit 1 is not affected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The cause of the low condenser vacuum was a momentary loss of sealing steam. The condenser remained viable for decay heat removal. All safety equipment is available. The grid is stable with the plant in its normal shutdown electrical configuration. | Shutdown Cooling Decay Heat Removal Control Rod | |
ENS 56710 | 2 September 2023 10:32:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge | Automatic Reactor Scram Due to Feedwater Transient | The following information was provided by the licensee via email: On 9/2/2023 at 0632 EDT, a feedwater transient occurred resulting in an reactor protection system (RPS) automatic reactor scram on low level (Level 3, 159.3 inches). Following the scram, reactor water level dropped below Level 2 (108.8 inches) resulting in a Group 2 recirculation sample system isolation, Group 3 traveling in-core probe (TIP) isolation valve isolation, Group 6 and 7 reactor water cleanup isolation, and Group 9 containment purge isolations. All control rods inserted as expected. High pressure core spray and reactor core isolation cooling initiated and injected as expected. ECCS systems have been secured and normal reactor pressure and level control has been established for hot shutdown. Nine Mile Point Unit 2 is stable and in Mode 3. These 4 hour and 8 hour non-emergency reports are 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). The NRC Resident was informed. There was no impact on Unit 1. | Feedwater Reactor Protection System Reactor Core Isolation Cooling High Pressure Core Spray Reactor Water Cleanup Control Rod | |
ENS 55821 | 5 April 2022 06:23:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge | Scram on LOW Level | The following information was provided by the licensee via telephone and email: On 4/5/2022, at time 0223, during maintenance on Feedwater Level Control Valve 2FWS-LV10B, a Feedwater transient occurred resulting in an RPS Automatic Reactor Scram on Low Level (Level 3, 159.3 inches). Following the scram, reactor water level dropped below Level 2 (108.8 inches) resulting in a Group 2 Recirculation Sample System Isolation, Group 3 TIP ((Traversing Incore Probe)) Isolation Valve Isolation, Group 6 and 7 Reactor Water Cleanup Isolation and Group 9 Containment Purge Isolations. All control rods inserted as expected. High Pressure Core Spray and Reactor Core Isolation Cooling initiated and injected as expected. ECCS Systems have been secured and normal reactor pressure and level control has been established for hot shutdown. Nine Mile Point Unit 2 is stable in Mode 3. These 4 hour and 8-hour non-emergency ENS ((Emergency Notification System)) reports are 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). The NRC Resident was informed. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: There was no impact on Unit 1. | Feedwater Reactor Core Isolation Cooling High Pressure Core Spray Reactor Water Cleanup Control Rod | |
ENS 54562 | 4 March 2020 17:05:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Scram in the Turbine Control System | At 1205 EST, on March 4, 2020, Nine Mile Point Unit 2 initiated a manual reactor scram due to lowering Electrohydraulic Control System (EHC) level in the turbine control system. The cause of the lowering level was a leak in the EHC system piping. All control rods inserted. There were no safety system actuations. The cause of the EHC leak is being investigated. The NRC Resident has been notified. Additionally, the licensee notified the New York State Public Service Commission. | Control Rod | |
ENS 54035 | 29 April 2019 20:33:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to Power Oscillations and High Pressure Coolant Injection System Initiation | During power ascension on April 29, 2019, at 1630 (EDT), Nine Mile Point Unit 1 power and pressure oscillations were observed with reactor power at approximately 82 (percent). At time 1633 (EDT), the reactor was manually scrammed when the scram criteria of greater than 4 (percent) APRM power oscillations were observed in accordance with special operating procedures. All control rods fully inserted and all plant systems responded per design following the scram. Following the manual 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 1633 (50 seconds after the reactor scram), RPV level was restored above the HPCI System low level actuation setpoint 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 cause of the power oscillations is currently under investigation. The NRC Resident Inspector was notified. The New York State public service commission was notified. | Feedwater High Pressure Coolant Injection Reactor Pressure Vessel Emergency Core Cooling System Control Rod | |
ENS 53998 | 14 April 2019 04:03:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram and Specified System Actuation | On 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. | Feedwater High Pressure Coolant Injection Reactor Pressure Vessel Emergency Core Cooling System Control Rod | |
ENS 53565 | 27 August 2018 04:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | En Revision Imported Date 8/29/2018 | 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.
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). | Feedwater Main Condenser Control Rod | |
ENS 52950 | 6 September 2017 15:57:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram on Low Reactor Vessel Water Level | On 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. | Reactor Coolant System Feedwater High Pressure Coolant Injection Main Steam Isolation Valve Core Spray Emergency Core Cooling System Decay Heat Removal Main Steam Line Safety Relief Valve Main Condenser Control Rod | 05000220/LER-2017-003 |
ENS 52889 | 6 August 2017 02:35:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Scram During Testing | At 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. | Feedwater Control Rod | |
ENS 52624 | 20 March 2017 06:27:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Scram Due to Pressure Oscillations | On 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). | 05000220/LER-2017-002 | |
ENS 52425 | 10 December 2016 13:48:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to High Main Turbine Vibrations | On 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. | Feedwater High Pressure Coolant Injection Main Turbine Reactor Pressure Vessel Emergency Core Cooling System Main Condenser | 05000220/LER-2017-001 |
ENS 51369 | 4 September 2015 13:16:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unplanned Automatic Scram and Specified System Actuations Due to Msiv Closure | On 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. | Reactor Coolant System Feedwater High Pressure Coolant Injection Main Steam Isolation Valve Core Spray Emergency Core Cooling System Main Steam Line Main Condenser Control Rod | 05000220/LER-2015-004 |
ENS 50830 | 18 February 2015 19:06:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Scram Due to Rapidly Rising Reactor Water Level | At 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. | Reactor Protection System | |
ENS 49888 | 10 March 2014 20:28:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Reactor Scram Due to Actuation of the Alternate Rod Insertion System | At 1628 EDT Nine Mile Point (NMP) Unit 2 experienced an actuation of the Alternate Rod Insertion (ARI) system which resulted in a reactor scram. Coincident with the scram, the Reactor Core Isolation Cooling (RCIC) system initiated. Prior to the event, maintenance personnel were working in the vicinity of a reactor vessel level instrumentation rack and may have agitated the common drain line of the transmitters. A prompt investigation is underway to investigate the incident. The actuation signal for the RCIC system was invalid because reactor vessel level did not reach level two and the actuation was not in response to actual plant conditions or parameters. 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 event has been entered into the NMP corrective action program as CR-2014-001963. The NRC Resident Inspector has been notified. The licensee has notified the State of New York. The reactor is shutdown with all rods inserted. Decay heat is being rejected to the condenser and reactor water level is being maintained by condensate, feedwater, reactor water clean up, and control rod drive systems. | Feedwater Reactor Protection System Reactor Core Isolation Cooling Control Rod | |
ENS 49868 | 4 March 2014 06:43:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unit 2 Manual Reactor Scram Following Loss of a Uninterruptible Power Supply (Ups) | At 0137 EST Nine Mile Point Unit 2 experienced a loss of an uninterruptible power supply 2VBB-UPS3B which resulted in a half scram and half isolations. This caused a loss of cooling water to the Reactor Recirculation Pumps and other indications for the loss of power. At 0143 EST a Manual Reactor Scram was inserted due to the rise of temperatures on the Reactor Recirculation Pump seal cavity temperature and motor winding temperature. The reactor building ventilation radiation monitor went non-functional when the reactor building isolated on the loss of UPS power. The standby gas treatment system was started as required and restored the reactor building differential pressure. This is a 4-Hour report for 10CFR50.72(b)(2)(iv)(B) RPS Actuation and 8-Hour report for 10CFR50.72(b)(3)(xiii) Loss of Emergency Assessment Capability. The NRC Resident inspector has been notified. All systems functioned as required following the manual scram. All control rods fully inserted. The cause of the loss of the UPS is under investigation. | Reactor Recirculation Pump Reactor Building Ventilation Standby Gas Treatment System Control Rod | |
ENS 49593 | 2 December 2013 14:04:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Scram Following Trip of Both Reactor Recirculation Pumps | At 0904 (EST) on Monday, December 2, 2013, Nine Mile Point Unit 2 was manually scrammed from approximately 40% thermal power due to the loss of both reactor recirculation pumps during a planned downpower evolution. Manual scram of the unit is procedurally required upon loss of both recirculation pumps to avoid potential power/flow oscillations. The reactor recirculation pumps failed to transfer to the low frequency motor generators when downshifted from fast speed. The cause of the loss of both reactor recirculation pumps is not known at this time. (Nine Mile Point Unit 2) NMP2 has commenced cooldown in preparation for the forced outage to investigate and commence repairs. 10 CFR 50.72(b)(2)(iv)(B) requires reporting within 4 hours of any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. All control rods fully inserted. No safety systems actuated. Decay heat is being removed via the main condenser. The "A" recirculation pump was restarted in low speed at 1045 EST. Unit 2 is in a normal shutdown electrical lineup. The licensee informed the NRC Resident Inspector and will inform the New York State Public Services Commission. | Reactor Protection System Reactor Recirculation Pump Main Condenser Control Rod | 05000410/LER-2013-004 |
ENS 48477 | 3 November 2012 12:23:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram on Low Reactor Water Level | On November 3, 2012 at 0823 EDT, Nine Mile Point Unit 1 experienced an automatic reactor scram on low reactor water level. All control rods fully inserted and all plant systems responded per design following the scram. Prior to the automatic scram, an unexpected high Reactor Pressure Vessel (RPV) water level was experienced, followed by a turbine trip and subsequent lowering of RPV water level to the RPV low level scram set point. The cause of the water level transient is unknown. Following the automatic scram, the High Pressure Coolant Injection (HPCI) System automatically initiated as expected. HPCI is a flow control mode of the normal feedwater systems, and is not an Emergency Core Cooling System. At 0824 EDT, 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. 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 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 NRC Resident Inspector. Unit 2 was not affected during this event. | Feedwater High Pressure Coolant Injection Reactor Pressure Vessel Emergency Core Cooling System Main Condenser Control Rod | 05000220/LER-2012-005 |
ENS 48453 | 29 October 2012 04:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Rps Actuation While Critical Due to Generator Load Reject | On October 29, 2012 at 2100 EDT, Nine Mile Point Unit 1 experienced an automatic reactor scram due to a generator load reject. The cause of the load reject is currently under investigation. 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 2101 EDT, 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. Three Electromatic Relief Valves actuated due to this scram and re-closed automatically. 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 bypass valves. Both Reserve Station Transformers are in service and being supplied by their normal power sources. Both Emergency Diesel Generators are operable and in standby. The unit is currently implementing post scram recovery procedures. The licensee has notified the NRC Resident Inspector. Notified R1DO (Caruso). | Feedwater High Pressure Coolant Injection Emergency Diesel Generator Reactor Pressure Vessel Emergency Core Cooling System Main Condenser Control Rod | |
ENS 48323 | 20 September 2012 13:23:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram and High Pressure Coolant Injection System Initiation | On September 20, 2012 at 0923 EDT, Nine Mile Point Unit 1 experienced an automatic reactor scram due to a turbine trip at power. The cause of the turbine trip is currently under investigation. 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 0924 EDT, 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. One 115kv off site power source (Line 4) is unavailable for planned maintenance at the James A Fitzpatrick Nuclear Power Plant. Both Reserve Station Transformers are in service and being supplied by the other 115kv offsite power source (Line 1). Both Emergency Diesel Generators are operable and in standby. The unit is currently implementing post scram recovery procedures. The licensee has notified the NRC Resident Inspector. Licensee has notified the state. | Feedwater High Pressure Coolant Injection Emergency Diesel Generator Reactor Pressure Vessel Emergency Core Cooling System Main Condenser Control Rod | 05000220/LER-2012-002 |
ENS 48110 | 17 July 2012 15:18:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram Due to High Neutron Flux | On July 17 2012, at 1118 (EDT), Nine Mile Point Unit 1 experienced an automatic reactor scram due to high neutron flux as measured by the Average Power Range Monitoring system. The cause is currently under investigation. All control rods fully inserted and all plant systems responded per design following the scram. The High Pressure Coolant Injection (HPCI) system, which is an operating mode of the feedwater system, initiated as expected. There were no planned activities in progress at the time which could have contributed to the event. 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. All emergency power sources are available in standby. The unit is currently implementing post scram recovery procedures. This was an uncomplicated Reactor Scram and the plant is stable with normal levels, temperature, and pressure. Offsite power is in a normal alignment. HPCI has been secured and returned to normal alignment. The cause to the high neutron flux is still under investigation. This event had no impact on Unit 2. The licensee has informed the NRC Resident Inspector and State Authorities. | Feedwater High Pressure Coolant Injection Main Condenser Control Rod | 05000220/LER-2012-001 |
ENS 48097 | 12 July 2012 06:20:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Reactor Scram Due to Lowering Condenser Vacuum | On July 12, 2012, at 0200 EDT, clean steam reboiler 'B' failed, causing a loss of sealing steam. This resulted in degrading condenser vacuum and rising off gas system pressure. The main steam backup supply for sealing steam also failed, and condenser vacuum and off gas system pressure continued to degrade. In response to rising off gas system pressure and lowering condenser vacuum, reactor power was lowered to 85% in accordance with Special Operating Procedures. With off gas system pressure approaching the procedural limit and condenser vacuum degrading rapidly, a manual reactor scram was inserted at 0220 EDT. All control rods fully inserted and all systems functioned as expected on the scram. Plant is currently shutdown and parameters are stable. The unit is currently implementing post scram recovery procedures and plant cooldown is in progress. The cause of the loss of both the primary and backup sources of sealing steam is under investigation. The shutdown electrical lineup is normal and decay heat is being removed via steam bypass valves to the main condenser. The licensee has notified the NRC Resident Inspector and the Public Service Commission. | Main Condenser Control Rod Main Steam | 05000410/LER-2012-004 |
ENS 47141 | 11 August 2011 04:16:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Manual Reactor Scram Inserted Due to a Feedwater Leak on a Min Flow Line | NMP2 inserted a manual reactor scram due to a through wall leak on feedwater pump 2FWS-P1A minimum flow line. 2FWS-P1A has been removed from service to minimize the leak. All control rods inserted and all systems functioned as designed. The unit will remain in hot shutdown until plant startup. All systems functioned as required and the scram was uncomplicated. The licensee plans to issue a press release and has informed the NRC Resident Inspector and the New York State Public Service Commission.
The licensee will not be issuing a press release regarding this manual scram. R1DO (Powell) notified. | Feedwater Control Rod | |
ENS 46808 | 3 May 2011 00:51:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Scram | Nine Mile Point Unit 1 experienced an automatic RPS actuation (scram) on Monday, May 02, 2011 at 2051. Cause of the RPS actuation is not understood at this time. All control rods inserted to position 00. N1-EOP-2 entered due to low reactor water level following trip (expected plant response). Reactor pressure stabilized 800 to 1000 psig, reactor water level restored and maintained 53 to 95 inches. Automatic initiation of the High Pressure Coolant Injection system occurred following plant trip (normal actuation). The reactor is stable in Hot Shutdown. The licensee characterized the scram as uncomplicated. All rods fully inserted, normal feed water is supplying the reactor with decay heat being removed to the condenser. The unit is in a normal shutdown electrical lineup and the scram had no impact on Unit 2. All systems functioned as required. The unit was operating at 47% power at the time of the event due to feed pump maintenance. The licensee does not have a first-out indication for the reactor scram and is still investigating the cause of the scram. The NRC Resident Inspector has been notified. | High Pressure Coolant Injection Control Rod | |
ENS 46409 | 10 November 2010 15:56:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unplanned Automatic Scram and High Pressure Coolant Injection System Initiation During Testing | At 10:56 (EST) on Wednesday, November 10, 2010, Nine Mile Point Unit (1) One automatically scrammed from rated power. The cause of the scram was Main Steam Isolation Valve (MSIV) closure. The MSIV closure occurred during Instrument and Control Lo-Lo Level Surveillance Testing. The Lo-Lo Surveillance Test has been secured and all Reactor Protection System (RPS) Level Signals returned to normal. Two of four MSIVs went closed; troubleshooting to follow to determine the cause of the equipment malfunction (unexpected MSIV closure). Following the automatic scram, the High Pressure Coolant Injection (HPCI) System automatically initiated. At Nine Mile Point Unit One, a HPCI System actuation signal on low Reactor Pressure Vessel (RPV) level is normally received following a reactor scram, due to level shrink. At 10:58, RPV level was restored above the HPCI System low level actuation set point and the HPCI System initiation signal was reset. Pressure control was initially established on the Emergency Condensers (ECS). The MSIVs have been re-opened and the normal heat removal capability has been re-established (to the Main Condensers). All off-site power sources remain available (with a normal electrical alignment). 10 CFR 50.72(b)(2)(iv)(B) requires reporting within 4 hours when a valid actuation of the Reactor Protection System occurs. 10 CFR 50.72(b)(3)(iv)(A) requires reporting within 8 hours when a valid actuation of the High Pressure Coolant Injection System occurs. There are no other adverse impacts to the station based on this event. All control rods inserted and the unit is stable in Mode 3 with reactor pressure and temperature approximately 600 psig and 480 degrees. All other safety systems operated as expected. The licensee notified the NRC Resident Inspector and the New York State Public Service Commission. | High Pressure Coolant Injection Reactor Protection System Main Steam Isolation Valve Reactor Pressure Vessel Main Condenser Control Rod | |
ENS 45612 | 7 January 2010 06:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Scram During Transmitter Venting | At 0100, Nine Mile Point Unit 2 reactor scrammed (on low reactor water level). The cause is currently under investigation. Maintenance activities were in progress on Residual Heat Removal (RHR) B & C systems. It is suspected that transmitter venting is the most probable cause of the trip. Reactor core isolation system (RCIC) injected on invalid level 2 signal. No safety relief valves (SRV's) actuated. B and C Residual Heat Removal systems (RHR) remain inoperable. All other ECCS systems and Emergency Diesel Generator are currently operable. Reactor water level is normal. No emergency core cooling system injection was required. The plant is currently in the hot shutdown condition. No emergency plan activation is required. Activation of forced outage plan is in progress. Lowest reactor water level reached during the transient was 140 inches. This is less than the reactor water level scram set point of 159.3 inches. Reactor pressure before scram was 1020 psig, current reactor pressure is 530 psig and reactor coolant temperature is 470 degrees F. Plant stack monitor is not available. Last grab sample reading at time 0257 is 857 micro-curies/sec. All systems functioned as required. All rods fully inserted on trip. Decay heat is being removed by steaming to the main condenser. The plant is in its normal shutdown electrical lineup. The licensee notified the NRC Resident Inspector. | Emergency Diesel Generator Residual Heat Removal Emergency Core Cooling System Safety Relief Valve Main Condenser | |
ENS 45412 | 5 October 2009 15:58:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Scram and High Pressure Coolant Injection Following a Loss of Feedwater Level Control | At 1158 on Monday, October 5, 2009, Nine Mile Point Unit One was manually scrammed from approximately 100% rated power due to failure of the Feedwater Level Control System, in anticipation of a reactor scram. Following the manual scram insertion at 11:58, High Pressure Coolant Injection (HPCI) System automatically initiated on low Reactor Vessel (RPV) level. At 11:59, RPV level was restored above the HPCI System low level actuation setpoint, and the HPCI System initiation signal was reset. At Nine Mile Point Unit One, a HPCI System actuation signal on low RPV level is normally received following a reactor scram, due to level shrink. Unit 1 has commenced cooldown, in preparation for the forced outage to commence repairs. Reactor water level is being controlled in the normal operating band; reactor temperature is 450?F and reactor pressure is approximately 500 psig. 10 CFR 50.72(b)(2)(iv)(B) requires reporting within 4 hours when any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. 10 CFR 50.72(b)(3)(iv)(A) requires reporting within 8 hours when a valid actuation of the High Pressure Coolant Injection System occurs. All control rods fully inserted. All systems functioned as required following the reactor scram. The reactor is currently stable in Mode 3. HPCI has been secured. Makeup water is being provided by the Reactor Feedwater System and decay heat removal is through the bypass valves to the condenser. There was no impact on Unit 2 and the plant is in a normal post-scram electrical lineup. The licensee notified the NRC Resident Inspector. | Feedwater High Pressure Coolant Injection Reactor Protection System Decay Heat Removal Control Rod | |
ENS 44598 | 24 October 2008 01:26:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to Loss of the Electronic Pressure Regulator | Control Room Operators observed slight (reactor) pressure rise during panel walk down. Investigation of pressure indication led Control room staff to determine that (the) EPR (Electronic Pressure Regulator) was not functioning properly (noise in the output signal). Control Room Staff entered Special Operating Procedure for failed pressure regulator. EPR could not be moved and this was confirmed by operators in the field. Control Room Staff (then) inserted a manual scram. Immediately after the scram reactor water level reached a low of 36", Emergency Operating Procedures for Level (EOP-2) were entered. HPCI initiated on the turbine trip to control water level. After the turbine tripped, all turbine bypass valves failed open; MSIVs (main steam isolation valve) were manually shut to control pressure. (The) EPR eventually disengaged from control, allowing the operator control of the turbine bypass valves. MSIVs were then reopened. (The) Scram has been reset. (The) turbine driven shaft pump did not initially disengage, pump (was) manually tripped after turbine speed reduced to 1500 rpm. All other systems responded correctly. (The) plant is not currently in any SOPs or EOPs and is proceeding to cold shutdown using normal operating procedures. All control rods fully inserted as expected. The plant is in a normal shutdown electrical lineup. At the time of the event, containment spray loop 1-12 was out of service for routine surveillance. The plant is currently cooling down and is at 365 psi. The licensee notified the NRC Resident Inspector. | Main Steam Isolation Valve Control Rod Containment Spray | |
ENS 42403 | 10 March 2006 03:14:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Scram Due to Loss of Condenser Vacuum Turbine Trip | This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B) RPS Actuation (scram) for Nine Mile Point Unit 2 which states '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.' On 03/09/2006 at 2214 while operating at approximately 85 % reactor power (coast down to refueling) a condenser low vacuum condition resulted in a turbine trip and a subsequent reactor scram. A loss of sealing steam most probably caused the loss of condenser vacuum and an investigation is in progress. Special Operating procedure N2-SOP-101 C was entered. All control rods inserted (fully) as expected. Condenser vacuum has been stabilized and the main steam isolation valves are open. The plant is stable and recovery actions are in progress. Decay heat is being removed via the turbine bypass valves to the main condenser. The condensate and feedwater system is in operation maintaining reactor vessel level. The electric plant is in a normal shutdown lineup and there was no effect from this transient on Unit 1. The licensee notified the NRC Resident Inspector.
This update is being made to provide additional information to EN# 42403 which was communicated via ENS on 3/10/06 at 0058 hours. During the scram that occurred at Nine Mile Point Unit 2 on 3/9/06 at 2214 hours, a primary containment isolation signal to RHR Shutdown Cooling, RHR Head Spray and RHR sample valves was received as designed. No components repositioned as the valves are normally closed during plant operations. The licensee will notify the NRC Resident Inspector. Notified R1DO (P. Krohn). | Feedwater Reactor Protection System Main Steam Isolation Valve Primary containment Shutdown Cooling Main Condenser Control Rod | |
ENS 41927 | 18 August 2005 13:49:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Scram Due to Loss of a Power Board | Unit 1 scrammed from 100% power due to a loss of power board 11 coincident with 1/2 scram present already on RPS channel 12 due to (instrumentation and control) (I&C) testing. A loss of power board 11 causes a loss of 11 RPS trip bus which in turn produces a 1/2 scram. Loss of power board 11 is currently under investigation. In addition during the scram, HPCI injected into the reactor vessel on a turbine trip signal to maintain reactor water level. Currently, the reactor is in hot shutdown with reactor water levels being maintained in the normal level band at 74 inches with feedwater in automatic. Reactor pressure is currently 920 psig and being maintained in automatic with turbine bypass valves. Plan is to stay in hot shutdown and complete scram recovery procedures. All control rods fully inserted. No safety relief valves actuated. Electrical busses were being supplied by normal offsite power. Emergency diesel generators are available. The decay heat removal path is currently normal feedwater to the reactor vessel through the turbine bypass valves to the condenser. There was no impact on Unit 2. The licensee is going to suspend any high risk maintenance activities on Unit 2. The licensee notified the NRC Resident Inspector. | Feedwater Emergency Diesel Generator Decay Heat Removal Safety Relief Valve Control Rod | |
ENS 41464 | 7 March 2005 09:37:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge | Automatic Turbine Trip/ Reactor Scram | The following information was provided by the licensee (text in quotes): At 0437 Unit 1 scrammed. The initiating event appears to be a turbine tripped initiated by a High level in 122 moisture separator drain tank. Investigating (the cause) of the scram will determine the actual cause. All control rods fully inserted into the core. HPCI initiated. Three relief valves lifted and reseated normally. The Reactor water clean up system is removing decay heat. The licensee will notify the NRC Resident Inspector. | Control Rod | 05000220/LER-2005-001 |
ENS 40998 | 30 August 2004 12:35:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unit 1 Manually Scrammed Due to Oscillating Reactor Vessel Water Level | Nine Mile Point, Unit One is initiating a 10 CFR 50.72 (b) (2) (iv) (B) 4-Hour Non-Emergency notification based upon insertion of a 'MANUAL' scram that occurred at 08:35 on Monday, August 30, 2004. At time of transient, plant was operating in Mode 1, Power Operating Condition, at 99.7% of rated power. At 08:25 on Monday, August 30, 2004, Operators noted oscillations on 13 Feedwater flow control valve (FCV) while in 'AUTOMATIC' mode of operation (normal mode of operation for this equipment). Operators took "MANUAL" control of 13 FCV per Plant Operating Procedures. 13 FCV oscillations continued while in the 'MANUAL' mode, and a decision was made to insert a 'MANUAL' scram at 08:35. All control rods fully inserted and the plant responded as designed to the scram. At 08:44, the scram signal was reset per procedure. Currently, plant is in Mode 2, Hot Shutdown Condition with cooldown in progress. Plant is transitioning to Mode 3, Cold Shutdown Condition, per Plant Operating Procedures. At the time the manual scram was inserted, Reactor Vessel Water Level (RVWL) was 67 inches and decreasing (automatic scram setpoint is 53 inches). The 13 FCV is on the discharge of the turbine-driven feedwater pump. Decay heat is currently being removed by the main condenser via the steam bypass valves. All ECCS and safety-related equipment is available, if needed. At the time of the transient there was no plant maintenance on-going which could have been a contributing factor. The licensee informed the NRC Resident Inspector.
The notification sent to the NRC on 8/30/04 at 11:42 was found to be incomplete. As a normal and expected response to a manual scram at high power, the High Pressure Coolant Injection System (feedwater) automatically initiated during the transient following the manual scram. This should have been reported as an 8 hour Non-Emergency 10CFR50. 72 (b) (3) (iv) (A) notification. The licensee notified the NRC Resident Inspector. Notified R1DO (Henderson). | Feedwater High Pressure Coolant Injection Main Condenser Control Rod | 05000220/LER-2004-004 |
ENS 40719 | 2 May 2004 06:17:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Manual Scram Due to Rising Torus Temperature Due to Stuck Open Erv | Operators inserted a manual scram at 0217 (EDT) in anticipation of torus bulk temperature approaching 110 degrees F following an Electromatic Relief Valve (ERV) failing to close during ERV testing. Technical Specification 3.3.2.e requires the insertion of a manual scram prior to torus bulk temperature reaching 110 degrees F. The maximum average torus temperature was 104 degrees F. Operators opened ERV 123 at 0209 for post maintenance testing from approximately 19% power. The ERV subsequently stuck open. Operators performed the off-normal procedure for a stuck open ERV, but this failed to shut the valve. This ported steam from the reactor vessel to the torus resulting in an uncontrolled torus temperature rise. Operators placed torus cooling in service but this did not stop the rising torus temperature. Following the manual scram, cooldown, and depressurization, shutdown cooling is being placed in service. Immediately following the manual scram, a turbine trip signal actuated the logic for high pressure coolant injection. High pressure coolant injection actuated and operators controlled level above 53 inches. With the ERV stuck open, the cooldown rate could not be controlled. The cooldown rate was approximately 190 degrees F during the first hour following the scram. All control rods fully inserted into the core. Decay heat is being removed by shutdown cooling (in service at the time of the report). The operators intend to cooldown to cold shutdown. The electrical buses are stable. Nine Mile Point Unit 2 was not affected. The licensee notified the NRC Resident Inspector. | High Pressure Coolant Injection Shutdown Cooling Control Rod |