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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 57032 | 16 March 2024 19:49:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip Due to Main Feedwater and Main Steam Isolations | The following information was provided by the licensee via phone and email: At 1449 CDT, Waterford 3 Steam Electric Station was operating at 100 percent power when a manual reactor trip was initiated due to main feed isolation valve (FW-184B) and main steam isolation valve (MS-124B) going closed unexpectedly. Emergency feedwater (EFW) was automatically actuated. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip. The unit is currently stable in Mode 3. All control rods fully inserted as expected. This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system (RPS) when the reactor is critical and as an 8-hour nonemergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as valid actuation of the EFW system. 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 through the turbine bypass valves and the atmospheric dump valve on loop '2'. There is no primary to secondary system leakage. The cause of the isolations is still being investigated. | Feedwater Reactor Protection System Main Steam Isolation Valve Control Rod Main Steam | |
| ENS 55963 | 25 June 2022 01:12:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Trip Due to Main Steam Isolation Valve Closure | The following information was provided by the licensee via email: At 2012 CDT, Waterford 3 Steam Electric Station, Unit 3 was operating at 100 percent power when an automatic reactor trip occurred due to Main Steam Isolation Valve MS-124B going closed unexpectedly. Subsequently, both main feedwater isolation valves shut. Emergency Feedwater (EFW) was automatically actuated. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip. The unit is currently stable in Mode 3. All control rods fully inserted as expected and all other plant equipment functioned as expected. This was an uncomplicated scram. This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system (RPS) when the reactor is critical and as an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as valid actuation of the EFW system. The NRC Resident Inspector has been notified. | Feedwater Reactor Protection System Main Steam Isolation Valve Control Rod | |
| ENS 55436 | 29 August 2021 23:04:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Safety System Actuation | At 1804 CDT on 8/29/2021, Waterford 3 Steam Electric Station (WF3) experienced a Loss of Off Site Power event due to Hurricane Ida (See EN #55435). This event caused an automatic actuation of Emergency Diesel Generators Trains A and B. Both Emergency Diesel Generators started as designed and both are currently operating normally supplying power to their respective Class 1E Safety Busses. This automatic actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). Prior to the loss of offsite power, WF3 was in progress of performing a plant cooldown in accordance with procedural guidance. As part of this cooldown and after entering Mode 4, all Safety Injection Tanks were isolated. As a result of losing offsite power, Reactor Coolant System Temperature increased above 350F which is above the temperature requirements for Mode 4. Safety Injection Tanks are required to be unisolated and OPERABLE in Mode 3. Therefore, with no Safety Injection Tanks OPERABLE, this constituted an event or condition that could have prevented the fulfillment of a safety function and the unit entered Technical Specification 3.0.3. The unit was in Technical Specification 3.0.3 for approximately 43 minutes from 1805 CDT until 1848 CDT when Mode 4 conditions were re-established. This event or condition that could have prevented the fulfillment of a Safety Function is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D). While continuing to perform the Reactor Coolant System Cooldown and prior to placing Shutdown Cooling Train in service, it became necessary to start one train of Emergency Feedwater. Emergency Feedwater Train A was manually started at 1847 CDT to feed the Steam Generators and was secured at 1947 CDT. Emergency Feedwater Train A started and operated normally during this period. This manual actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector.
The purpose of this notification is to revise Event Notification Report (EN) 55436 to include a partial retraction. On August 29, 2021, Waterford Steam Electric Station, Unit 3 (WF3) experienced a loss of offsite power (LOOP) event due to Hurricane Ida. Prior to the LOOP, WF3 had shutdown to Mode 3 (Hot Standby) in anticipation of the LOOP and was performing a plant cooldown in accordance with procedural guidance. When Mode 4 (Hot Shutdown) was achieved, all Safety Injection Tanks (SITs) were isolated as part of the plant cooldown. After the LOOP, Reactor Coolant System (RCS) temperature increased and the Core Exit Thermocouples (CETs) indicated that RCS temperature had exceeded 350 degrees F. Based on the CETs, this was above the temperature requirements for Mode 4 and, as such, WF3 declared entry into Mode 3. The SITs are required to be unisolated and Operable in Mode 3. Since no SITs were Operable at that time, it was determined that this constituted an event or condition that could have prevented the fulfillment of a safety function and included this as part of the EN 55436 report in accordance with 10 CFR 50.72(b)(3)(v)(D). An engineering evaluation has subsequently been performed to validate whether the RCS temperature excursion following the LOOP actually reached 350 degrees F. As defined in WF3 Technical Specification (TS) Table 1.2, Operational Mode temperatures are a function of RCS average temperature (Tavg), not just the indicated temperature of the CETs. Based on the calculated Tavg using validated temperatures, it was concluded that 350 degrees F was not reached. Thus, WF3 remained in Mode 4 following the LOOP and there was no event or condition that could have prevented the fulfillment of a safety function that was reportable pursuant to 10 CFR 50.72(b)(3)(v)(D). The remainder of EN 55436 remains correct and unchanged. The licensee notified the NRC Resident Inspector. Notified R4DO (Pick) | Steam Generator Reactor Coolant System Feedwater Emergency Diesel Generator Shutdown Cooling | |
| ENS 54978 | 2 November 2020 10:19:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Trip Due to Control Element Drive Mechanism Control System Timer Failure | On November 2, 2020, at 0419 CST, Waterford 3 experienced an automatic reactor trip due to a Control Element Drive Mechanism Control System timer failure while attempting to synchronize a second motor generator set. All control rods fully inserted. The plant is currently in Mode 3 and stable with normal feedwater feeding and maintaining both Steam Generators. The NRC Senior Resident Inspector has been notified. The cause of the failure is still under investigation. | Steam Generator Feedwater Control Rod | |
| ENS 54068 | 16 May 2019 18:48:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Trip Due to Turbine Trip | This is a non-emergency notification from Waterford 3. On May 16, 2019, at 1348 CDT, Waterford 3 experienced an automatic reactor trip due to Steam Generator number 1 high level, which was the result of a Main Turbine trip and subsequent reactor power cutback which had occurred at 1345 CDT. The cause of the Main Turbine trip is currently under investigation. Subsequent to the Reactor trip, Main Feedwater Isolation Valves number 1 and number 2 closed on high Steam Generator levels. Emergency Feedwater automatically actuated for Steam Generator number 2 at 1419 CDT and Steam Generator number 1 at 1425 CDT. Main Feedwater was restored to both Steam Generators by 1629 CDT. The plant entered the Emergency Operating Procedure for an uncomplicated reactor trip and is in the process of transitioning to the normal operating shutdown procedure. The plant is currently in Mode 3 and stable with Main Feedwater feeding and maintaining both Steam Generators. The NRC Senior Resident Inspector has been notified. All control rods fully inserted. Decay heat is being removed through the main condenser. The plant is in a normal shutdown electrical lineup. | Steam Generator Feedwater Main Condenser Control Rod | |
| ENS 52863 | 17 July 2017 21:17:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unusual Event Declared Due to Loss of Offsite Power | During a rain and lightning storm, plant operators observed arcing from the main transformer bus duct and notified the control room. The decision was made to trip the main generator which resulted in an automatic reactor trip. The plant entered EAL SU.1 as a result of the loss of offsite power for greater than fifteen minutes. Plant safety busses are being supplied by both emergency diesel generators while the licensee inspects the electrical system to determine any damage prior to bringing offsite power back into the facility. Offsite power is available to the facility. No offsite assistance was requested by the licensee. During the trip, all rods inserted into the core. Decay heat is being removed via the atmospheric dump valves with emergency feedwater supplying the steam generators. The main steam isolation valves were manually closed to protect the main condenser. There were no safeties or relief valves that actuated during the plant transient. There is no known primary-to-secondary leakage. Reactor cooling is via natural circulation. All safety equipment is available for the safe shutdown of the plant. The licensee has notified the NRC Resident Inspector, Louisiana Department of Environmental Quality and the local Parish emergency management agencies. Notified DHS SWO, FEMA, DHS NICC, FEMA National Watch Center (email) and Nuclear SSA (email).
This notification is also made under 10 CFR 50.72(b)(3)(v)(D). This is a non-emergency notification from Waterford 3. On July 17, 2017 at 1606 CDT, the reactor automatically tripped due to a loss of Forced Circulation, which was the result of Loss of Offsite Power (LOOP) to the electrical (safety and non-safety) buses. Both 'A' and 'B' trains of Emergency Diesel Generators (EDGs) started as designed to reenergize the 'A' and 'B' safety buses. The LOOP caused a loss of feedwater pumps, resulting in an automatic actuation of the Emergency Feedwater (EFW) system. Prior to the reactor trip, at 1600 CDT, personnel noticed the isophase bus duct to main transformer 'B' glowing orange due to an unknown reason. Due to this, the main turbine was manually tripped at 1606 CDT. Following the turbine trip, the electrical (safety and non-safety) buses did not transfer to the startup transformers as expected due to an unknown reason. The plant entered the Emergency Operating Procedure for LOOP/Loss of Forced Circulation Recovery. At 1617 CDT, an Unusual Event was declared due to Initiating Condition (IC) SU1 - Loss of all offsite AC power to safety buses (greater than) 15 minutes. All safety systems responded as expected. The plant is currently in mode 3 and stable with the EDGs supplying both safety buses and with EFW feeding and maintaining both steam generators. Offsite power is in the process of being restored. The licensee has notified the NRC Resident Inspector, Louisiana Department of Environmental Quality and the local Parish emergency management agencies.
The licensee terminated the Notification of Unusual Event at 2056 CDT. The basis for terminating was that offsite power was restored to the safety busses. The licensee has notified Louisiana Department of Environmental Quality, St. John and St. Charles Parishes, Louisiana Homeland Security Emergency Preparedness, and will be notifying the NRC Resident Inspector. Notified IRD (Stapleton), NRR (King), R4DO (Hipschman), DHS SWO, FEMA, DHS NICC, FEMA National Watch Center (email) and Nuclear SSA (email).
This update is being reported under 10 CFR 50.72(b)(3)(v)(B). During the event discussed in EN# 52863, at 1642 CDT (on July 17, 2017), Condensate Storage Pool (CSP) level lowered to less than 92% resulting in entry to Technical Specification (TS) 3.7.1.3. Level in the CSP was lowered due to feeding from both Steam Generators with EFW. Normal makeup to the CSP was temporarily unavailable due to the LOOP. Filling the CSP commenced at 1815 CDT (on July 17, 2017), and TS 3.7.1.3 was exited on July 18, 2017 at 0039 CDT. The licensee notified the NRC Resident Inspector. Notified R4DO (Hipschman).
Waterford 3 is retracting a follow up notification made on July 19, 2017 for EN# 52863, concerning the loss of safety function associated with the Condensate Storage Pool (CSP) per 10 CFR 50.72(b)(3)(v)(B). The Condensate Storage Pool was performing its required safety function by providing inventory to the Emergency Feed Water pumps when the required Tech Spec level (T.S. 3.7.1.3) dropped below 92%. The Technical Specification was entered at 1624 (CDT) on July 17, 2017 and exited after filling at 0039 on July 18, 2017. The total allowed outage time allowed by Tech Spec 3.7.1.3 is 10 hours to be in Hot Shutdown if not restored. The Condensate Storage Pool level was restored to greater than 92% prior to exceeding the allowed outage time. Based on level being restored and the Condensate Storage Pool performing its required safety function, 10 CFR 50.72(b)(3)(v)(B) does not apply. Prior to the automatic reactor trip, Condensate Storage Pool level was greater than 92%. The NRC Resident Inspector has been notified of the retraction. Notified R4DO (Groom). | Steam Generator Feedwater Emergency Diesel Generator Main Steam Isolation Valve Main Transformer Main Turbine Main Condenser | 05000382/LER-2017-002 |
| ENS 51447 | 4 October 2015 04:07:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Trip | At 2307 CDT Waterford 3 experienced an automatic reactor trip and all Control Element Assemblies (CEAs) inserted into the core. The cause of the automatic reactor trip is currently under investigation. The plant is currently in Mode 3 (Hot Standby) and stable with Main Feedwater feeding and maintaining both Steam Generators. Main Feedwater Pump 'A' tripped subsequent to the reactor trip. Emergency Feedwater actuated following the plant trip as expected, but was not required to maintain Steam Generator level. The plant entered the Emergency Operating Procedure for an uncomplicated reactor trip and has now transitioned to the normal operating shutdown procedure. Unit 3 is in a normal post trip electrical lineup. The Main Condenser is in-service removing decay heat.. The licensee informed the NRC Resident Inspector. | Steam Generator Feedwater Main Condenser | |
| ENS 51116 | 3 June 2015 22:05:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip Due to Loss of Main Feedwater Pump | This is a non-emergency notification from Waterford 3. At 1705 (CDT) the reactor was manually tripped in anticipation of an automatic trip due to loss of main feedwater pump 'A'. The plant is currently in mode 3 and stable with emergency feedwater feeding and maintaining both steam generators due to an automatic emergency feed actuation signal. During the trip, the 'B' electrical safety and non safety busses did not automatically transfer from the unit auxiliary transformer to the startup transformer causing a loss of off-site power to the 'B' electrical busses. This resulted in a loss of main feedwater pump 'B'. The 'B' emergency diesel generator started as designed and reenergized the 'B' safety related buses. The plant entered the emergency operating procedure for loss of main feedwater. Off-site power has been restored to the 'B' safety and non safety busses, and the emergency diesel generator 'B' is secured. All control rods fully inserted into the core following the trip. Decay heat is being removed by the main condenser using the turbine bypass valves. The electric plant is in a normal shutdown lineup. The licensee has notified the NRC Resident Inspector. | Steam Generator Feedwater Emergency Diesel Generator Main Condenser Control Rod | |
| ENS 48687 | 21 January 2013 21:51:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Trip Due to Low Steam Generator Level | At 15:51 CST, Waterford 3 experienced an uncomplicated automatic reactor trip from 84.5% reactor power. The actuations of the Reactor Protection System (RPS) and the Emergency Feedwater Actuation System (EFAS) resulted from Steam Generator #1 Low Level, which is at a nominal 27.4% narrow range setpoint. Safety systems responded as expected. All three (3) Emergency Feedwater Pumps started and injected into Steam Generator #1. Auxiliary Feedwater pump has been started, feeding both Steam Generators (#1 and #2) at levels above the EFAS low level setpoint. All control rods inserted by the automatic RPS actuation. Electrical power is being supplied from normal off-site power and condenser vacuum is available for Steam Generator heat removal via the Steam Dump Bypass Control system. There are no safety systems out of service or inoperable, nor any safety system TS (Technical Specification) LCO (Limiting Condition for Operation) actions entered. The cause of the Steam Generator #1 Low Level condition, and associated Reactor Trip, is under investigation. This event occurred during the initial power escalation from refuel outage RF18, after attempting to place C Heater Drain Pump (HDP), the first of three, into service. After starting, C HDP tripped for a reason not yet verified. Subsequently, based on initial Control Room operator observations, the Steam Generator #1 Main Feedwater control valve position was observed to be at 10-20% open, but with an open position demand signal of 100%. Main Feedwater response to the reactor trip (Reactor Trip Override) was as expected. The NRC Resident Inspector has been informed. * * * UPDATE FROM WILLIAM HARDIN TO PETE SNYDER AT 1645 EST ON 3/7/13 * * * The original reactor power level stated in the report should be 91% in lieu of 84.5%. This information has been changed in the event heading. The licensee notified the NRC Resident Inspector. Notified R4DO (Werner). | Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater Control Rod | |
| ENS 45445 | 19 October 2009 14:44:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip Following Stuck Open Moisture Separator Heater Relief Valve | At approximately 0915 CDT on 10/19/09 a Waterford 3 Moisture Separator Heater shell-slide relief valve (RS-203B) inadvertently opened, causing reactor power to increase from 100% to approximately 100.27% Rated Thermal Power (RTP). Operations reduced Main Turbine-Generator load by approximately 26 megawatts to restore reactor power to less than 100% RTP. At approximately 0942 CDT, Operations commenced a rapid plant shutdown because the relief valve would not re-close. At approximately 0944 CDT, Operations manually tripped the reactor due to a low condenser hot well level, just prior to reaching the Condensate Pumps Trip setpoint, to avoid a loss of Main Feedwater event. The Plant Protection System (PPS) responded as designed, resulting in an uncomplicated reactor trip. Emergency Feedwater Actuation Signal (EFAS) was received on low Steam Generator level as expected from reactor trip at or near full power. Steam Generator levels remained above the EFAS injection level setpoint so that actual injection of Emergency Feedwater did not occur. No other PPS actuation occurred. The plant is currently being maintained in Mode 3. Waterford 3 plans to commence refueling outage (RF16) at this time, approximately 1 - 2 days earlier than scheduled. The licensee notified the NRC Resident Inspector. | Steam Generator Feedwater | |
| ENS 42138 | 12 November 2005 02:34:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip After Loss of All Condenser Circulating Water Pumps | Waterford 3 manually tripped the reactor at 20:34 (CST) on 11/11/05 due to lowering main condenser vacuum caused by a loss of all circ water pumps. Subsequently an Emergency Feedwater Actuation Signal (EFAS) was received due to low steam generator levels. The plant is currently being maintained in mode 3 with both Steam Generators being fed from the Auxiliary Feedwater system with Steam Generator levels in the normal operational band for mode 3. The EFAS has been reset. The plant will be maintained in Mode 3 while a Post Trip Review is performed. This report is submitted as required by 10CFR50.72. All control rods fully inserted on the manual trip. The main steam isolation valves are shut and the heat sink is through the atmospheric dump valves. The electrical grid is stable and plant power is from the startup transformer. No primary or secondary relief valves or safety valves lifted. The site was able to restart the B & D circ water pumps. There is no significant steam generator tube leakage. The licensee notified the NRC Resident Inspector.
This notification is an update to an immediate notification that was called into the NRC Operations Center at 04:48 (eastern time) on November 12, 2005 (Event # 42138). The event was reported as an 8-hour event. This update to the original notification is to communicate that, based on further review, the event notification should have been made within 4 hours since it was reportable within 4 hours as well as the 8-hour reporting criteria and therefore the call should have been made within the 4 hour period. The condition is reportable under four hour reporting criteria 50.72(b)(2)(iv)(B) for a manual trip of the plant in anticipation of receiving a RPS Trip with the Reactor critical. The condition is reportable within eight hour reporting criteria 50.72(b)(3)(iv)(A) for the automatic actuation of EFAS upon low steam generator levels. This update does not report a change to the event description reported. As mentioned in the original report, Waterford 3 manually tripped the reactor at 20:34 on November 11, 2005 due to lowering main condenser vacuum caused by a loss of all circulating water pumps. Subsequently an Emergency Feedwater Actuation Signal (EFAS) was received due to low steam generator levels. The plant was then maintained in Mode 3 with both steam generators being fed from the Auxiliary Feedwater System with steam generator levels in the normal operational band for Mode 3. The EFAS had been reset at the time of the original notification. The plant was maintained in Mode 3 while a Post Trip Review was performed. Further details of the event will be reported under the 60 day LER reporting criteria. The licensee notified the NRC Resident Inspector. R4DO (Clark) notified. | Steam Generator Feedwater Main Steam Isolation Valve Auxiliary Feedwater Main Condenser Control Rod |