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| Entered date | Site | Region | Scram | Reactor type | Event description | |
|---|---|---|---|---|---|---|
| ENS 56087 | 3 September 2022 01:58:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | The following information was provided by the licensee via email: On 09/02/2022 at 22:48 with Unit 1 at 40% power, the reactor was manually tripped due to a loss of the only operating main feed pump which caused lowering level in the steam generators. All systems responded as expected following the trip. Auxiliary feed actuation signal occurred due to lowering steam generator levels. The cause of the main feedwater pump trip is under investigation. St. Lucie Unit 2 was not affected and remains at 100% power. This event is being reported pursuant to 10 CFR 50.72 (b)(2)(iv)(B) for the reactor trip and 10 CFR 50.72 (b)(3)(iv)(A) for the auxiliary feed actuation. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Decay heat is being removed by using the atmospheric dump valves. |
| ENS 55641 | 10 December 2021 13:35:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 12/10/2021, at 1024 EST, with Unit 1 at 100 percent power, the reactor was manually tripped due to lowering level in the steam generators. All systems responded as expected following the trip. The reactor is currently stable in Mode 3 and operators restored steam generator level utilizing main feedwater. The cause of the reduction in feedwater flow is under investigation. St. Lucie Unit 2 was not affected and remains at 100 percent power. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B) for the reactor trip. The NRC Resident Inspector has been notified. All rods inserted into the core during the trip. The plant is in its normal shutdown electrical lineup. Decay heat is being maintained by steam discharge to the main condenser using the turbine bypass valves. |
| ENS 55078 | 20 January 2021 21:48:00 | Saint Lucie | NRC Region 2 | Automatic Scram | CE | On 1/20/2021 at 1822 EST, with Unit 2 in Mode 1 at 100 percent power, the reactor automatically tripped due to a loss of Motor Control Center 2B2. The trip was uncomplicated with all systems responding normally post trip. Operations stabilized the plant in Mode 3. Auxiliary feed-water automatically actuated on the 2A Steam Generator post trip. Current decay heat removal is the 2B main feedwater pump to both steam generators and the Steam Bypass Control System to the main condenser. Unit 1 is not affected. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B). The NRC Resident Inspector has been notified. |
| ENS 54027 | 25 April 2019 12:04:00 | Saint Lucie | NRC Region 2 | Automatic Scram | At 0918 (EDT) on 4/25/19, with (Saint Lucie) Unit 1 in Mode 1 at 100% power, the reactor automatically tripped due to a Turbine Trip. The reactor trip was uncomplicated with all systems responding normally. Operations is maintaining the plant stable in Mode 3. Decay heat removal is being accomplished by main feed water and the main condenser using the turbine steam bypass valves. Unit 2 is not affected and remains at 100% power. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B). The NRC Resident Inspector has been notified. | |
| ENS 53703 | 29 October 2018 16:47:00 | Saint Lucie | NRC Region 2 | Manual Scram | On October 29, 2018 at 1317 EDT, with St. Lucie Unit 1 in Mode 1 at 100% power, the reactor was manually tripped due to inadequate feedwater flow to both 1A and 1B Steam Generators (S/Gs). The trip was uncomplicated with all systems responding normally post-trip. (All control rods fully inserted and there were no specified system actuations.) Operators responded and stabilized the plant in Mode 3. The cause of the inadequate feed flow to the 1A and 1B Steam Generators is currently under investigation. Decay Heat removal is being accomplished through forced circulation with stable conditions from Main Feedwater and the Steam Bypass Control System to the Main Condenser. Currently maintaining Pressurizer pressure at 2250 psia and Reactor Coolant System temperature at 532 degrees F. St. Lucie Unit 2 was unaffected and remains in Mode 1 at 100% power. This report is submitted in accordance with 10CFR50.72(b)(2)(iv)(B) for the reactor trip. The NRC Senior Resident Inspector has been notified. | |
| ENS 53036 | 26 October 2017 05:54:00 | Saint Lucie | NRC Region 2 | Automatic Scram | CE | On October 26, 2017 at 0212 EDT St. Lucie Unit 2 experienced a reactor trip due to a loss of load event resulting in an RPS (Reactor Protection System) actuation. The cause of the loss of load is currently under investigation. Following the reactor trip, an Auxiliary Feedwater Actuation Signal occurred due to low level in the 2A Steam Generator. One of the two Main Feed Isolation Valves to the 2A Steam Generator did not close on the Auxiliary Feedwater Actuation Signal. 2A Steam Generator level was restored by Auxiliary Feedwater. The 2B Steam Generator level is being maintained by Main Feedwater. All CEAs (Control Element Assemblies) fully inserted into the core. Decay heat removal is being accomplished through forced circulation with stable conditions from Auxiliary Feedwater/Main Feedwater and Steam Bypass Control System. Currently maintaining pressurizer pressure at 2250 psia and Reactor Coolant System temperature at 532 degrees F. St. Lucie Unit 1 was unaffected and remains in Mode 1 at 100 percent power. This report is submitted in accordance with 10 CFR 50.72(b)(2)(iv)(B) for the reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for the Specified System Actuation. The licensee notified the NRC Resident Inspector. |
| ENS 51302 | 10 August 2015 00:23:00 | Saint Lucie | NRC Region 2 | Automatic Scram | CE | On August 9, 2015, during the performance of Reactor Protection System Logic Matrix Testing, a reactor trip occurred. All CEA's (control rods) fully inserted into the core. Decay Heat removal is from Main Feedwater and Steam Bypass to the Main Condenser. All equipment operated as expected. Currently maintaining pressurizer pressure at 2250 psia, temperature maintaining at 532 degrees F. Unit 2 was unaffected and remains in Mode 1 at 100% power. This event is reportable pursuant to 10CFR 50.72(b)(2)(iv)(B) for the Reactor Trip and 10CFR 50.72(b)(3)(iv)(A) for the Specified System Actuation. The plant is in its normal shutdown electrical lineup. No safety or relief valves lifted during this event. The cause of the trip is under investigation. The licensee notified the NRC Resident Inspector. |
| ENS 50607 | 12 November 2014 18:31:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On November 12, 2014 at 1548 (EST), Unit 2 was manually tripped due to a lowering 2B steam generator level caused by the spurious (slow) closure of 2B Main Feedwater Isolation Valve, HCV-09-2B. All CEAs (control element assemblies) fully inserted into the core. All safety systems responded as expected with the 2B Auxiliary Feedwater Actuation System Channel 2 (AFAS 2) actuating on low 2B steam generator level. Decay heat removal is from main feedwater to the 2A steam generator and manual control of auxiliary feedwater to the 2B steam generator, with steam bypass to the main condenser. This event is reportable pursuant to 10 CFR 50.72(b)(2)(iv)(B) for the reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for the AFAS 2 actuation. During the transient, no relief or safety valves lifted. The grid is stable and the plant is in its normal shutdown electrical lineup at normal operating pressure and temperature. The cause of the feedwater isolation valve malfunction is under investigation. There was no effect on Unit 1. The licensee has notified the NRC Resident Inspector. |
| ENS 49536 | 14 November 2013 14:57:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On November 14, 2013 at 1218 EST, Unit 2 was manually tripped due to a lowering 2B Steam Generator level caused by the spurious closure of 2B Main Feedwater Isolation Valve HCV-09-2A. All CEAs (Control Element Assemblies) fully inserted into the core. All safety systems responded as expected with the 2B Train Auxiliary Feedwater Actuation System Channel 2 (AFAS 2) actuating on low 2B Steam Generator level. Decay Heat Removal is from Main Feedwater to the 2A Steam Generator and Auxiliary Feedwater to the 2B Steam Generator with Steam Bypass to the Main Condenser. This event is reportable pursuant to 10CFR 50.72(b)(2)(iv)(B) for the Reactor Trip and 10CFR 50.72(b)(3)(iv)(A) for the AFAS 2 actuation. The plant is in its normal shutdown electrical lineup. No safeties or relief valves lifted during this event. The NRC Resident Inspector has been notified by the licensee. |
| ENS 49528 | 12 November 2013 01:23:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 0002 EST, Unit 1 Manually tripped the Reactor from 90% power due to an unisolable leak in the Digital Electro-Hydraulic (DEH) System. All CEAs fully inserted into the Reactor Core. All systems responded as expected on the trip. Decay Heat removal currently using Main Feedwater and Steam Bypass Control System. After the trip, DEH pumps were secured to stop the transfer of fluid from the DEH system to the Turbine Building. Investigation ongoing to determine exact location of the leak. This condition is reportable pursuant to 10CFR50.72(b)(2)(iv)(B). The was no impact on Unit 2. The NRC Resident Inspector has been notified. |
| ENS 49082 | 31 May 2013 10:26:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On May 31, 2013 at 0712 (EDT), Unit 2 (reactor) was manually tripped due to high differential pressure on the debris filter for the 2A1 Condenser Waterbox which required a trip of the 2A1 Circulating Water Pump. The 2A2 Condenser Waterbox and the 2A2 Circulating Water Pump were already removed from service due to a suspected condenser tube leak. All CEAs (Control Element Assembly) fully inserted into the core. Decay heat removal is from main feedwater and steam bypass to the main condenser. The cause of the rising differential pressure on the 2A1 debris filter was potentially due to an influx of algae. This event is reportable pursuant to 10CFR 50.72(b)(2)(iv)(B) for the reactor trip. The reactor trip response is considered uncomplicated and the unit is stable in Mode 3 at normal temperature and pressure. Unit 2 is in a normal shutdown electrical lineup. There was no impact on Unit 1. The licensee has notified the NRC Resident Inspector. |
| ENS 48818 | 12 March 2013 18:01:00 | Saint Lucie | NRC Region 2 | Automatic Scram | CE | On 3/12/13 at 1451 EDT, during normal full power operations, Unit 1 automatically tripped due to the Thermal Margin/ Low Pressure trip setpoint being exceeded. The trip was uncomplicated and all CEAs (control element assembly) fully inserted when the reactor was tripped. Main Steam Safety valves lifted momentarily post trip and reseated. No automatic safety system actuations were required and none occurred. The cause and details of the automatic trip are under investigation. The plant is stable in Mode 3 at normal operating temperature and pressure. RCS Heat Removal is being maintained with Main Feedwater and Atmospheric Dump Valves in operation. The operation of the Steam Bypass Control System is under review by Engineering. The Offsite power grid is available and stable. The licensee has notified the NRC Resident Inspector and there was no impact on Unit 2. |
| ENS 47915 | 11 May 2012 07:07:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On May 11, 2012, a failure of the High Power Feed Regulating Valve FCV-9011 resulted in '2A' S/G water level lowering. Manual operator control of the Main Feed Regulating system was unsuccessful in stabilizing S/G water level. '2A' S/G level lowered to the procedurally required manual reactor trip criteria. The crew inserted a manual trip. All CEAs fully inserted into the core. Following the trip, Auxiliary Feedwater actuated as designed and decay heat removal was via Auxiliary Feedwater and Steam Bypass to the Main Condenser. All equipment operated as expected. Currently, Unit 2 is maintaining pressurizer pressure at 2250 psia, temperature at 532 degrees F on Main Feedwater (using Low Power Feed Regulating Valves LCV-9005/9006) and Steam Bypass Control. 'Unit 1 was unaffected and remains in Mode 1 at 29% power. This event is reportable pursuant to 10CFR50.72(b)(2)(iv)(B) for the Reactor Trip, as well as 10CFR50.72(b)(3)(iv)(A) for specified system actuation (Auxiliary Feedwater). The licensee has notified the NRC Resident Inspector. |
| ENS 47793 | 31 March 2012 03:42:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 0022 (EDT) on 03/31/12 while maintaining power stable at 10% for Steam Bypass Control System testing, Unit 1 was manually tripped due to an uncontrolled cooldown caused by PCV-8802 (Steam Bypass Control Valve) unexpectedly opening. Following the trip, PCV-8802 closed and the secondary was isolated by closing the Main Steam Isolation Valves per Standard Post Trip Actions. Following isolation of the steam demand, the trip was uncomplicated with all CEAs fully inserted. No automatic safety system actuations were required and none occurred. The cause of the unexpected opening of the Steam Bypass Control System valve is under investigation. The plant is stable in Mode 3 at normal operating temperature and pressure. RCS Heat Removal is being maintained with Auxiliary Feedwater and Atmospheric Dump Valves. The Offsite power grid is available and stable. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to manual RPS actuation with the reactor at power. The RCS cooled down from 532 degree to 515 degrees over a period of approximately 2 minutes and 40 seconds. The reactor was manually tripped when RCS temperature reached 515 degrees and the lowest RCS temperature observed after the trip was 505 degrees. The licensee has notified the NRC Resident Inspector. |
| ENS 47752 | 19 March 2012 02:24:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 2336 EDT, during performance at Low Power Physics Testing, Unit 1 was manually tripped while the reactor was critical at less than 1% power due to Control Element Assembly (CEA) Regulating Group #3 exhibiting anomalous behavior (continued to insert with no operator action). The trip was uncomplicated and all CEAs fully inserted when the reactor was tripped. No automatic safety system actuations were required and none occurred. The cause for the abnormal CEA performance is under investigation. The plant is stable in Mode 3 at normal operating temperature and pressure. RCS Heat Removal is being maintained with Auxiliary Feedwater and Atmospheric Dump Valves. The offsite power grid is available and stable. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to manual RPS actuation with the reactor critical The NRC Resident Inspector has been informed. |
| ENS 47353 | 19 October 2011 07:32:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On October 19, 2011, at 0528, Unit 1 was manually tripped due to rising condenser backpressure. All (Control Element Assembly) CEAs fully inserted into the core. Decay Heat Removal is from Main Feedwater and Steam Bypass to the Main Condenser. The cause of the rising backpressure was an unplanned trip the Circulating Water Pump 1A1, which degraded the Circulating Water System performance. At the time of the trip, an additional Circulating Water Pump 1A2 was secured for planned maintenance. The cause of the Circulating Water Pump 1A1 trip is under investigation. This event is reportable pursuant to 10CFR 50.72(b)(2)(iv)(B) for the Reactor Trip. The plant is stable at normal operating temperature and pressure. The licensee notified the NRC Resident Inspector. |
| ENS 47178 | 22 August 2011 17:48:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On August 22, 2011 at 1513 (hrs. EDT), Unit 1 was manually tripped due to rising condenser backpressure. All CEAs fully inserted into the core. Decay heat removal was initially from main feedwater and steam bypass to the main condenser. The cause of the rising back pressure was an influx of jellyfish into the intake structure, degrading the circulating water system performance. Subsequent to the manual trip, the 1B Main Feedwater Pump was manually secured due to a leak on the pump casing. The 1A Main Feedwater Pump subsequently tripped due to low suction pressure after manually securing the 1B Condensate Pump, per procedure. Decay heat removal was transitioned to atmospheric dump valves and auxiliary feedwater. Unit 2 is in Mode 1, currently at 70 % power. Unit 2 power is being reduced from 100% in response to the influx of jellyfish. This event is reportable pursuant to 10 CFR 50.72(b)(2)(iv)(B) for the reactor trip. During the transient, no primary or secondary relief valves lifted. Offsite power is stable and the plant is in its normal shutdown electrical line-up with power being supplied from offsite. There is no known primary-to-secondary leakage. The cause of the 1A Main Feedwater Pump trip is under investigation. Unit 2 remained at 70% reactor power before and after the event. The licensee has notified the NRC Resident Inspector.
On August 22, 2011 an abnormal fish kill of at least 1000 lbs was observed in the combined unit's intake canal. The cause of the fish kill was related to an unusually large sustained influx of jellyfish into the intake canal. Per the plant's environmental permit, the Florida Fish and Wildlife Conservation Commission (FWCC) was notified at 1627 EDT. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(xi) due to the notification of the FWCC. The licensee has notified the NRC Resident Inspector. |
| ENS 46018 | 16 June 2010 19:20:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 1710 EDT, Unit 1 was manually tripped due to two dropped control rods. All CEAs (Control Element Assemblies) fully inserted on the trip. Steam generator level control responded as expected and no pressurizer or power operated relief valves opened. RCS heat removal is being maintained by main feedwater and steam bypass control systems. All other systems functioned normally and the plant has stabilized at normal operating temperature and pressure in Mode 3. This non-emergency notification is being made pursuant 10 CFR 50.72(b)(2)(iv)(B) due to manual actuation of RPS. The licensee characterized the manual trip as uncomplicated. The second rod dropped within a very short time of the first rod. The cause of the rod drops is still under investigation. The licensee noted that no activities involving the rod control system were in progress when the event occurred. The licensee was at 45% as part of its post outage power ascension unrelated to the rod drop. The manual reactor trip action was taken per procedure when the second rod dropped. The reactor trip had no impact on Unit 2 operation. The NRC Resident Inspector has been notified. |
| ENS 45843 | 15 April 2010 17:49:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 1539 (EDT), Unit 2 was manually tripped due to lifting of the 2B moisture separator reheater relief valve. The Unit commenced a rapid downpower and then a manual reactor trip was initiated at approximately 95% power. All CEA's (control element assemblies) fully inserted on the trip. Auxiliary feedwater automatically initiated on low steam generator level due the 2A steam generator 15% feedwater bypass not opening. No pressurizer power operated relief valves (PORVs) opened. RCS heat removal is now being maintained with auxiliary feedwater and the steam bypass control system. Main feedwater is available. All other systems functioned normally, and the plant is stabilized at normal operating temperature and pressure in Mode 3. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to manual RPS actuation and 10 CFR 50.72(b)(3)(iv)(A) due to auxiliary feedwater system actuation. The licensee notified the NRC Resident Inspector. |
| ENS 45374 | 21 September 2009 16:05:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 1227 EDT, a reactor startup was commenced on Unit 2. Mode 2 was entered at 1325 EDT. At 1333, a Reactor Control Operator noted that Primary Safety Valve V1202 had indications that it was leaking past its seat. Plant procedures required reducing RCS (Reactor Coolant System) pressure in 100 psi increments until the safety reseated. This event required the plant pressure to be reduced to 200 psi below Normal Operating Pressure. Prior to commencing the depressurization, a manual reactor trip was ordered by the Unit Supervisor as discussed in the pre-evolution brief. The unit was in Mode 2 approaching criticality at the time of the trip. The unit is currently stable in Mode 3, Hot Standby. The reactor trip was uncomplicated. All equipment operated as expected. Main feedwater remained available during the entire event. Auxiliary Feedwater and Atmospheric Dump Valves remained in service during the entire event. Unit 1 was unaffected by the event and remained at full power. The grid remained stable throughout the event. All control rods fully inserted. The licensee notified the NRC Resident Inspector. |
| ENS 45200 | 13 July 2009 11:37:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 07/13/2009 at 00:38 EDT a planned manual reactor trip was initiated on Unit 2 based on increased, unidentified RCS leakage. The RCS leakage had increased over a four day period. The downpower was initiated at 21:32 EDT from 100% power and proceeded in a controlled manner to 25% power. The reactor was manually tripped at 00:38 EDT, as planned. Following the reactor trip, EOP-1, Standard Post Trip Actions, and EOP-2, Reactor Trip Recovery procedures were completed and the unit was stabilized in Mode 3. Decay heat was removed by the Steam Bypass Control System (SBCS) to the condenser. The Main Feedwater Pump unexpectedly tripped on low suction pressure just prior to the reactor trip, but was recovered prior to levels reaching the Auxiliary Feedwater Actuation (AFAS) setpoint. There were no further major equipment failures identified post trip. On 7/13/2009 at 07:00 EDT a Containment walkdown confirmed the leak was caused by a J-joint weld defect on the 2B2 RCP Seal injection line. The leak is classified as reactor coolant pressure boundary leakage. The plant is in the process of cooling down to enter Mode 5 as required by Technical Specification 3.4.6.2.a. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(3)(ii)(A). Additional investigation is being performed to determine the cause of the leak. The initial leak rate was less than 0.2 gpm. The repair will require taking the plant to a reduced inventory. The licensee notified the NRC Resident Inspector |
| ENS 44952 | 1 April 2009 20:51:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 1805, due to lowering Condenser Vacuum caused by ingress of algae and seaweed, Unit 2 was manually tripped. Power had been reduced to 94% for the securing of one Circulating Water Pump (2A1). It was then identified that 2A2 Circulating Water Debris filter differential pressure was above administrative limits of 200 inches water. While the station was making preparations to reduce Circulating water flow on the 2A2 Circulating Water Pump, the unit began losing condenser vacuum. Plant was manually tripped at 92% power. All CEA's fully inserted on the trip. Auxiliary Feedwater automatically initiated on Low Steam Generator Level. No PZR PORVS opened. RCS Heat removal is now being maintained with Main Feedwater and Steam Bypass control system. All systems functioned normally, and plant is stabilized at normal operating Temperature and Pressure. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to manual RPS actuation and 10 CFR 50.72(b)(3)(iv)(B) due to PWR auxiliary feedwater system actuation. There was no impact on Unit 1. The licensee informed the Resident Inspector. |
| ENS 44276 | 7 June 2008 11:19:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 6/7/08 at 0818 hours, an unplanned manual reactor trip was initiated on St. Lucie Unit 2 from 100% power due to a trip of the 2B Condensate Pump, which led to a trip of the 2B Main Feedwater Pump (MFP) and decreasing Steam Generator (S/G) levels. The reactor was manually tripped due to decreasing S/G levels. Following the reactor trip, EOP-1, Standard Post Trip Actions and EOP-2, Reactor Trip Recovery procedures were completed and Unit 2 was stabilized in Mode 3. All control rods fully inserted. The Main Steam Safety Valves lifted as expected. Feedwater to the S/Gs was initially supplied by the 2A (MFP) until Auxiliary Feedwater Actuation System (AFAS) actuated as expected on low S/G level. Subsequently, the Auxiliary Feedwater Pumps restored S/G levels. Unit 2 electrical requirements were provided from offsite power. Other than the trip of the 2B Condensate Pump (initiating event) there were no major equipment failures. Unit 1 was not affected by this event. The grid is stable. Decay heat is being removed by the Auxiliary Feedwater Pumps feeding the S/Gs steaming to the bypass valves in the Condenser. The licensee notified the NRC Resident Inspector. |
| ENS 44268 | 4 June 2008 21:10:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 6/4/2008 at 17:30 hrs an unplanned manual reactor trip was initiated on St. Lucie Unit 2 from 100% power due to a trip of the 2B Heater Drain pump leading to a trip of the 2A Main Feedwater Pump and decreasing S/G levels. The Reactor was manually tripped due to decreasing Steam Generator levels. Following the reactor trip, EOP-1, Standard Post Trip Actions, and EOP-2, Reactor Trip Recovery procedures were completed and Unit 2 was stabilized in Mode 3. All control rods fully inserted. The S/G Safety Valves lifted and the last valve reseated at 950 psig. Feedwater to the S/G was supplied by the 2B Main FW Pumps and then the Auxiliary Feedwater Pumps. Unit 2 electrical requirements are provided from offsite power. All safe shutdown equipment operated as expected. There were no major equipment failures. Unit 1 was not affected by this event. The Grid is stable. The licensee notified the NRC Resident Inspector. |
| ENS 43941 | 29 January 2008 06:30:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | St Lucie Plant, Unit 2, manually tripped the reactor at 0531 hrs. EST, as part of a controlled reactor plant shutdown, in response to an RCS leak rate of 0.28 gpm, indicated to be associated with the 2B1 Reactor Coolant Pump seal package. All systems functioned as expected, satisfactorily. All CEAs fully inserted. Decay Heat removal is with Steam Generators and Main Feedwater. This report is made pursuant to 10 CFR 50.72(b)(2)(iv)(B). Unit 2 will cooldown to Mode 5 for repairs. The licensee informed the NRC Resident Inspector.
St. Lucie Plant, Unit 2, reported their manual reactor trip of 0531 hrs. EST, at 0630 hrs. EST, for an unidentified leak associated with the 2B1 RCP seal package (EN 43941). Subsequent investigation, reported to the STA (Shift Technical Advisor) at 1015 hrs. EST, determined that this leak constitutes an RCS Pressure Boundary Leak. This leak is at a pipe-to-flange weld on the outboard side of the first flanged coupling of the 2B1 RCP Upper Cavity Seal pressure sensing line. Investigation is in progress to determine the detailed configuration at the leak and root cause. There were NO ESFAS signals or actuations. Decay Heat Removal continues on Steam Generators, with MFW (Main Feedwater) and SBCS (Steam Bypass Control System); Off-Site power continues (to be) available and stable; Unit 1 at 100% power with operations and conditions normal. This report is made pursuant to 10 CFR 50.72(b)(3)(ii)(A). The licensee informed the NRC Resident Inspector of this update. Notified R2DO (Bonser). |
| ENS 43874 | 29 December 2007 07:54:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | At 2320, on 12/28/07, a Reactor Startup was commenced. At 0025, on 12/29/07 Subgroup #15, of Regulating Group #3, was placed on the hold bus. Placing the Subgroup on the hold bus was a pre-planned action that was briefed prior to the reactor startup, in accordance with an approved interim engineering disposition. The interim engineering disposition was written and approved on 12/28/07 for concerns over CEA #1, of Subgroup #15, dropping into the core unexpectedly. Subgroup #15, of Regulating Group #3, contains five CEA's (CEA # 60, 62, 64, 66 and 1). At 0047, all Regulating Group CEA's, with the exception of Regulating Group #5, were placed at the Upper Electrical Limit (136 inches withdrawn). Regulating Group #5 was at 120 inches withdrawn in preparation for diluting to criticality. At 0107, the dilution to criticality was commenced. At 0131, all 5 CEA's in Subgroup #15 slipped into the core approximately 20 inches. A manual reactor trip was then ordered by the unit supervisor. 2-EOP-1, 'Standard Post Trip Actions' was then performed. The unit was borated to shutdown boron concentration. All Safety Functions were met satisfactorily and 2-EOP-1 was exited. The unit was in Mode 3 approaching Mode 2 at the time of the trip. The unit is currently stable in Mode 3, Hot Standby. Reactor coolant pump heat is being removed using the atmospheric steam dumps. The licensee notified the NRC Resident Inspector. |
| ENS 43580 | 19 August 2007 22:19:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 08/18/2007 at 16:03 EDT a Planned Manual Reactor Trip was initiated on Unit 2 based on increased unidentified RCS leakage. The RCS leakage had increased over a two day period and surpassed the hard limit of 0.28 gpm established by a plant Operational Decision Making (ODM) plan. The downpower was initiated on 08/18/07 at 10:35 EDT from 100% power and proceeded in a controlled manner to 25% power. The Feedwater Control System was maintained in the automatic mode. Station Power was transferred by procedure from the Auxiliary to the Startup Transformers. The reactor was manually tripped at 16:03 EDT. Following the reactor trip, EOP-1, Standard Post Trip Actions, and EOP-2, Reactor Trip Recovery procedures were completed without contingencies and the unit was stabilized in Mode 3. Decay heat was removed by the Steam Bypass Control System (SBCS) to the condenser. The Steam Generators were fed by the MFW System and levels remained above Auxiliary Feedwater Actuation (AFAS) setpoint. There were no significant equipment failures identified post trip. The plant was cooled down and entered Mode 5 on 8/19/07 at 15:09 EDT. On 8/19/07 at 17:00 EDT while in Mode 5, a Containment walkdown confirmed the 2B1 RCP Seal injection line to be the only active RCS leakage source. The leak is unisolable from the RCS and is located at or adjacent to a socket weld on the 3/4" Class 1 Schedule 160 seal injection line. Removal of obstructions and insulation must occur before the specific details of the leak can be identified. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(3)(ii)(A). Additional investigation is being perform to determine the detailed configuration of the leak and the root cause. The licensee notified the NRC Resident Inspector. |
| ENS 42647 | 16 June 2006 02:18:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 6/15/06 at 2223 hrs an unplanned manual reactor trip was initiated on St. Lucie Unit 2 from 45% power due to severe DEH Leak on the #1 Throttle Valve. DEH Leak ceased upon Turbine Trip. Following the reactor trip, EOP-1, Standard Post Trip Actions, and EOP-2, Reactor Trip Recovery procedures were completed without contingencies and Unit 2 was stabilized in Mode 3. All control rods fully inserted and no S/G Safety Valves Lifted. Feedwater to the S/G was supplied by the main FW Pumps. All safe shutdown equipment operated as expected. There were no major equipment failures. Decay heat is being removed with main feedwater and dumping steam to the condenser. The grid is stable. The fire brigade was activated following the trip and set a fire watch (no fire). The NRC Resident Inspector was notified of this event by the licensee. |
| ENS 42277 | 20 January 2006 12:49:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 1/20/2006 at 0730 hrs, a Unit 2 control room annunciator was received indicating high conductivity/sodium in the main condenser. The Chemistry Dept. confirmed the sodium level was high indicating saltwater intrusion from a tube leak in the 2B2 Condenser Waterbox. Per the Secondary Chemistry Off-Normal Procedure, a rapid downpower to less than 5% power was initiated to remove the affected waterbox from service. It was decided to go ahead and remove Unit 2 from service rather than remain critical at a low power level. The downpower was planned to decrease power to approximately 25%, perform a manual transfer of plant electrics to the auxiliary transformers, and then manually trip the reactor in accordance with plant procedures. All systems worked as planned during the downpower and the reactor was manually tripped at approximately 25% power at 08:56 hrs. Standard Post Trip Actions and the Reactor Trip Recovery Procedure were carried out without incident. All control rods fully inserted and no Steam Generator (S/G) Safety Valves lifted. Feedwater to the S/G was supplied by the Main Feedwater pumps during the shutdown and later transferred to the Auxiliary Feedwater pumps. All safe shutdown equipment operated as expected. The plant is stable in Mode 3, Hot Standby conditions, with decay heat removal being accomplished by steaming through the Atmospheric Dump Valves. The Main Feedwater pumps remain available if needed. Unit 1 was not affected by this event. The licensee notified the NRC Resident Inspector. |
| ENS 41911 | 11 August 2005 14:33:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On 8/11/2005, a manual reactor trip was initiated due to lowering steam generator level caused by a partial loss of main Feedwater. The partial loss of feedwater was caused by the differential lock out of the non-vital 2A2 4160 V bus which resulted in loss of the 2A Condensate Pump that tripped the 2A Main Feedwater Pump. All rods inserted and no Steam Generator Safety Valves lifted. The differential lock out of the non-vital 2A2 4160 V (bus) deenergized the 2A3 vital 4160V bus, starting the 2A Emergency Diesel Generator and the 2A3 loads were sequenced on the Emergency Diesel Generator per design. Subsequently, the Auxiliary Feedwater System was automatically initiated due to lowering steam generator levels. All safe shutdown equipment operated as expected. The plant is stable in Mode 3, Hot Standby conditions, with decay heat removal being accomplished by steaming to the Main Condenser and Feedwater to the steam generators supplied by the Main Feedwater system. The Offsite power grid is available and stable. The '2C' Auxiliary Feedwater Pump was out of service for routine surveillance and it had no effect on the cause of the trip nor had any effect on the trip recovery. St. Lucie is investigating the cause of the lockout on the 2A2 4160V bus. Unit 1 was not affected by this event. At the time of this report, the 2A Emergency Diesel Generator was still loaded while investigations were underway. Steam generator level is being maintained using main feed. The licensee notified the NRC Resident Inspector. |
| ENS 41297 | 27 December 2004 18:49:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | The licensee reported a "manual reactor trip due to low steam generator level caused by feedwater control system malfunction." The licensee stated that it manually tripped the reactor with steam generator water level at approximately 40% and decreasing. Steam generator water level control was restored following the trip using auxiliary feedwater. All rods fully inserted on the trip. No safety or relief valves lifted. Auxiliary feedwater was manually actuated and decay heat is currently being discharged via the atmospheric dump valves. Unit 1 is at full power and unaffected and the grid is stable. The plant was in no major LCOs at the time. All systems functioned as required. The licensee is still investigating the feedwater control system malfunction. The NRC Resident Inspector has been notified.
The original notification stated that decay heat was being discharged via the atmospheric dump valves post-trip when the decay heat removal mechanism being used was steam dump to the condenser via the steam bypass control system. Additionally, although the auxiliary feedwater system was used to deliver water to the steam generators post-trip, the main feedwater system was available for this function. The investigation into the feedwater malfunction is still in progress. The NRC Resident Inspector has been informed. R2DO (Moorman) notified. |
| ENS 41293 | 25 December 2004 08:55:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | Manual reactor trip due to condensate pump failure. All systems functioned as required post trip. The plant is currently stable in Mode 3. On 12/25/04 Unit 2 at St. Lucie experienced a high amperage reading on a condensate pump. Visual observation of the pump indicated blistering paint at the electrical connections. The condensate pump was taken out of service and Unit 2 was manually shut down. Decay heat is being removed via normal means to the condenser. The AFW system started as expected. All rods inserted correctly and all systems functioned as designed. The licensee notified the NRC Resident Inspector.
The licensee called to provide some additional information concerning this event: 1) The manual trip of Unit 2 was due to the failure of the 2B condensate pump. 2) The condensate pump failure was a result of a failed termination of the "A" phase motor lead to the field cable. 3) The failure of the motor lead is considered a random event and does not have an generic implications. The licensee also noted that the reactor power had actually been reduced to 95% immediately prior to the manual trip. The NRC Resident Inspector and R2DO (Julian) have been notified.
The following information was obtained from the licensee via facsimile: This notification is an amended notification to the original notification of unit trip and RPS actuation due to failure of 2B condensate pump. The amended notification includes an 8-hour notification non-emergency 10 CFR 50.72 (b)(3)(iv)(A) to identify Aux Feedwater Actuation automatically actuated post manual reactor trip on 12/25/04. Specified System Actuation per 50.72 (b)(3)(iv)(B)(6) AFAS (Auxiliary Feedwater Actuation System). The licensee notified the NRC Resident inspector. R2DO (Julian) notified of this update. |
| ENS 41018 | 4 September 2004 05:40:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | While reducing power in response to expected severe weather conditions from hurricane Frances, the reactor was manually tripped from 21% reactor power. The reactor was tripped because of significant swings in the 'B' Steam Generator level caused by erratic operation of the 'B' Feedwater Regulating Valve (FRV). All Control Element Assemblies fully inserted. Decay heat is currently being removed by Main Feedwater using the low power FRV bypass valves and Steam Bypass Control System (SBCS), maintaining RCS temperature at 532 degrees Fahrenheit. The unit will be maintained in a shutdown condition until repairs to the FRV are completed and the severe weather from Hurricane Frances abates. All primary and secondary systems performed as expected with the exception of the SBCS. The SBCS consists of five pressure control valves, PCV-8801 through PCV-8805 with PCV-8801 a larger capacity valve and designed to open first. The remaining valves are designed to open in series with overlap through their operating ranges. PCV-8801 failed to open and PCV-8802, 8803, and 8804 did not appear to properly control RCS temperature. PCV-8805 was operated in manual to control (steam generator) pressure. The Licensee notified the NRC Resident Inspector.
Florida Power and Light (FPL) is retracting this notification because the feedwater issues during the shutdown were not causal to the manual reactor trip. The St. Lucie Emergency Plan, requires that the units be taken offline prior to the onset of hurricane force winds onsite. In accordance with these requirements, St. Lucie Unit 2 was being taken offline prior to the arrival of hurricane Frances. Although automatic feedwater issues occurred during the downpower, the operators successfully took manual control of the main feedwater system. A reactor trip was not necessary to mitigate the condition, and continued operation and on-line troubleshooting would have been practical had the plant not been required to be shutdown for the approaching hurricane. The main feedwater control issues were not relevant factors during the planned plant shutdown/manual reactor trip. Therefore FPL is retracting this notification. The licensee notified the NRC Resident Inspector. Notified R2DO(Boland). |
| ENS 40403 | 20 December 2003 13:00:00 | Saint Lucie | NRC Region 2 | Automatic Scram | CE | On December 20, 2003, at 0949 hours, an automatic reactor trip occurred due to a loss of excitation of the turbine generator. All plant safety functions were maintained throughout the event. The plant was stabilized in Mode 3. All plant safety systems responded normally with the exception of the 2C Auxiliary Feedwater Pump (steam driven) which tripped on mechanical overspeed. The 2A and 2B Auxiliary Feedwater Pumps (electric driven) functioned normally to restore the 2A and 2B Steam Generator levels. Post trip system anomalies include RCS Letdown isolated, Steam Generator Blowdown isolation valves closed, Control Room ventilation system swapped to recirculation mode, and the Fuel Handling Building ventilation system swapped to the Shield Building. An Emergency Response Team has been formed to review these conditions prior to plant restart. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to the automatic RPS Reactor Trip. All controls inserted properly. Decay heat is being removed using the turbine bypass valves. The Licensee notified the NRC Resident Inspector.
This update is provided to include the 10CFR50.72(b)(3)(iv)(A) notification criterion for the auxiliary feedwater actuation. The NRC Resident Inspector was notified., Reg 2 RDO(Fredrickson) was informed. |
| ENS 40375 | 4 December 2003 20:14:00 | Saint Lucie | NRC Region 2 | Manual Scram | CE | On December 4, 2003, at 1605 hours, a down power was initiated due to a failing bearing on the 2A Condensate Pump. The pump bearing was hot and smoking. The plant fire team was deployed as a precautionary action. Due to continued degradation of the Pump bearing, a Manual Reactor Trip was initiated at approximately 60% power. Feed to the 2A and 2B Steam Generators was maintained via the 2B Main Feedwater Pump. All plant safety systems responded normally and plant safety functions were maintained throughout the event. The Plant was stabilized In Mode 3. Plant post trip anomalies include Steam Generator Blowdown isolation valves closed, Control Room ventilation system swapped to recirculation mode, the Fuel Handling Building ventilation system swapped to the Shield Building, and it was necessary to take Steam Bypass Control System to manual. An Emergency Response Team was formed to review these conditions prior to plant restart. This non-emergency notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) due to the manual initiation of the RPS Reactor Trip. All control rods fully inserted into the reactor on the trip. The emergency diesel generators are available and the offsite electrical grid is in a normal configuration. No safety relief valves or power operated relief valves were known to have actuated during this event. St. Lucie Unit 1 was not affected and continues to operate in mode 1 at 100% rated thermal power. The licensee has notified the NRC Resident Inspector. |