| Site | Start date | Title | Description |
---|
ENS 57237 | South Texas | 24 July 2024 12:02:00 | Notification of Unusual Event Due to Loss of Offsite Power | The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
A Notification of Unusual Event was declared by South Texas Project Unit 1 at 0718 CDT for emergency action level (EAL) SU.1, loss of all offsite power for greater than 15 minutes, following a fire in the switchyard. Unit 1 tripped following the loss of power and is stable in Mode 3. Unit 2 reduced power to 90 percent but was otherwise unaffected by this event. Offsite services responded to the switchyard fire. The fire was extinguished at 0925 CDT.
There is no radioactive release and no threat to public safety.
The licensee notified state and local authorities and the NRC senior resident inspector.
Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), CWMD Watch Desk (email), DHS NRCC THD Desk (email), and DHS Nuclear SSA (email).
- * * UPDATE ON 7/24/2024 AT 1154 EDT FROM CHRIS VAN FLEET TO ERNEST WEST * * *
The following information was provided by the licensee via phone and email:
At 0702 CDT on 7/24/2024, with Unit 1 in Mode 1 at 100 percent power, the Unit 1 reactor automatically tripped due to loss of offsite power. The trip was not complex, with all systems responding normally post-trip. No equipment was inoperable prior to the event that contributed to the event or adversely impacted plant response to the scram.
Operations responded and stabilized the plant. Decay heat is being removed by steam generator power operated relief valves (PORV). Unit 2 was reduced in power to approximately 90 percent power due to conditions in the switchyard.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
There was no impact on the health and safety of the public or plant personnel. The NRC resident inspector has been notified.
Notified R4DO (Azua)
- * * UPDATE ON 7/24/2024 AT 1259 EDT FROM CHRIS MCRARY TO ERNEST WEST * * *
The following is a summary of information provided by the licensee via phone:
At 1146 CDT, South Texas Project Unit 1 terminated the previously declared Notification of Unusual Event due to restoration of an offsite source of electrical power.
Notified R4DO (Azua), NRR EO (McKenna), IR MOC (Crouch), DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), CWMD Watch Desk (email), DHS NRCC THD Desk (email), and DHS Nuclear SSA (email).
- * * UPDATE ON 7/24/2024 AT 1555 EDT FROM CHRIS VAN FLEET TO ERNEST WEST * * *
The following information was provided by the licensee via phone and email:
For the 10 CFR 50.72(b)(3)(iv)(A) reporting requirements:
At 0702 CDT on 7/24/2024, with both Unit 1 and 2 in Mode 1 at 100 percent power, the South Texas Project (STP) north and south switchyard electrical buses were de-energized.
In Unit 1, all emergency diesel generators (EDGs) 11, 12, and 13 automatically started in response to loss of offsite power on train `A', `B', and `C' engineered safety feature (ESF) buses.
Also in Unit 1, trains `A', `B', and `C' of the auxiliary feedwater (AFW) system automatically started.
In Unit 2, EDG 22 automatically started in response to loss of offsite power on the train `B' ESF bus.
Also in Unit 2, train `B' of the AFW system automatically started.
This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in the valid actuation of a pressurized water reactor auxiliary feedwater system (50.72(b)(3)(iv)(B)(6)) and emergency alternating current (AC) electrical power system (50.72(b)(3)(iv)(B)(8)). There was no impact on the health and safety of the public or plant personnel. The NRC resident inspector has been notified.
For the 10 CFR 50.72(b)(2)(xi) reporting requirement:
A news release was completed at 1140 CDT on 7/24/2024, by South Texas Project on the declaration of the Unusual Event. This media release is being reported in accordance with 10 CFR 50.72(b)(2)(xi): Any event or situation, related to the health and safety of the public or onsite personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made.
Notified R4DO (Azua) | ENS 57214 | Watts Bar | 8 July 2024 19:21:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
At 1521 EDT on July 8, 2024, with Unit 1 in Mode 1 at 100 percent power, the reactor automatically tripped due to a main turbine trip. The (reactor) trip was not complex with all systems responding normally post trip.
Operations responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the steam dump system and the auxiliary feedwater (AFW) system. Unit 2 is not affected.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). The expected actuation of the AFW system (an engineered safety feature) is being reported as an eight-hour report under 10 CFR 50.72(b)(3)(iv)(A).
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 specific cause of the turbine trip is under investigation by the licensee. | ENS 57195 | Cook | 27 June 2024 12:04:00 | Automatic Start of Turbine Driven Auxiliary Feedwater Pump | The following information was provided by the licensee email:
On June 27, 2024, at 0804 (EDT), D.C. Cook Unit 2 had an automatic start of the turbine driven auxiliary feedwater pump (TDAFP) following a controlled down power and manual reactor trip at approximately 17 percent power. The automatic start of the TDAFP was due to a steam generator water level 'low low' signal following the reactor trip. The down power and trip were performed in accordance with normal shutdown procedures to comply with the required action C.1 of technical specification 3.4.13, 'reactor coolant system operational leakage.' Reference event notification number EN57194.
An automatic start of the TDAFP is an eight hour report per 10CFR 50.72(b)(3)(iv)(A).
Unit 2 is being supplied by offsite power. All control rods fully inserted. Steam generators are being fed by both motor driven auxiliary feedwater pumps. Decay heat is being removed via the steam dump system to the main condenser. Preliminary evaluation indicates plant systems functioned normally following the reactor trip. D.C. Cook Unit 2 remains in Mode 3 to repair the previously reported reactor coolant system leakage through valve 2-QRV-251, 'CVCS (chemical and volume control system) charging pumps discharge flow control' valve packing.
The NRC Resident Inspector has been notified. | ENS 57177 | Saint Lucie | 18 June 2024 07:17:00 | Manual Reactor Trip | The following information was provided by the licensee by email:
On 06/18/2024 at 0317 EDT with Unit 2 at 18 percent power, the reactor was manually tripped due to elevated secondary chemistry levels (sodium and chlorides).
The trip was uncomplicated with all systems responding normally post trip. Operations stabilized the plant in Mode 3. Decay heat is being removed by auxiliary feedwater and atmospheric dump valves.
St. Lucie Unit 1 was unaffected and remains at 100 percent power.
This event is being reported pursuant 10CFR 50.72(b)(2)(iv)(B).
The NRC Resident Inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
All rods fully inserted. An investigation is underway to determine the root cause of the elevated chemistry levels.
- * * RETRACTION ON 6/24/2024 AT 1315 FROM BOB MURRELL TO ADAM KOZIOL * * *
The following retraction was provided by the licensee via email:
The purpose of this notification is to retract a previous report made on 06/18/2024 at 0652 (EDT) (EN# 57177). Notification of the event to the NRC was initially made because of inserting a manual reactor trip due to elevated secondary chemistry levels (sodium and chlorides).
After the initial report, Florida Power and Light has concluded that the event did not meet the reporting requirements on 10 CFR 50.72(b)(2)(iv)(B) since it was part of a normal plant shutdown.
Therefore, this event is not considered an unplanned scram and is not reportable to the NRC as a Licensee Event Report per 10 CFR 50.73.
The NRC Senior Resident Inspector has been notified. | ENS 57158 | Surry | 2 June 2024 21:08:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
Surry Unit 1 reactor automatically tripped at 1708 EDT on 6/2/24 due to a turbine trip (with the reactor operating at greater than 10 percent reactor power).
The turbine control system is currently under investigation. Reactor coolant temperature is being maintained via main steam dumps with main feedwater supplying the steam generators.
All systems operated as required. The trip was uncomplicated and all control rods fully inserted into the core. There was no emergency core cooling system (ECCS) or auxiliary feedwater system actuation. Offsite power remains available. There is no impact to Surry Unit 2.
This notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) for 4-hour notification of reactor protection system activation. The NRC Resident Inspector has been notified.
There were no radiation releases, personnel injuries, or contamination events due to this event. | ENS 57148 | North Anna | 29 May 2024 10:24:00 | Automatic Reactor Trip | The following information was provided by the licensee via email and phone:
On May 29, 2024, at 0624 EDT, Unit 1 automatically tripped from 100 percent power due to a negative rate trip. The unit has been stabilized in mode 3 at normal operating temperature and pressure. The reactor trip was uncomplicated and all control rods fully inserted into the core. This reactor protection system actuation is reportable per 10 CFR 50.72(b)(2)(iv)(B). The auxiliary feedwater pumps actuated as designed because of the reactor trip and is reportable per 10 CFR 50.72(b)(3)(iv)(A) for a valid engineered safety feature (ESF) actuation. Decay heat is being removed by the condenser steam dump system and Unit 1 is in a normal shutdown electrical lineup. Unit 2 was not affected by this event.
The NRC Resident has been notified. | ENS 57132 | Beaver Valley | 19 May 2024 04:30:00 | Manual Reactor Trip | The following information was provided by the licensee via email:
At 0030 (EDT) on 5/19/24, with Beaver Valley Unit 1 in mode 1 at 14 percent power, the reactor was manually tripped due to inability to control the A steam generator water level. The trip was not complex, with all systems responding normally post-trip. The turbine driven auxiliary feedwater pump automatically started on a valid actuation signal. All control rods inserted into the core. Operations responded and stabilized the plant. Decay heat is being removed by the feedwater system and the main condenser. Beaver Valley Unit 2 is unaffected.
Due to the reactor protection system system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Due to the emergency safety feature system actuation (automatic start of the turbine driven auxiliary feedwater pump) while critical, this event is being reported as an eight-hour, non-emergency notification per 10CFR 50.72(b)(3)(iv)(A).
There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector has been verbally notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Unit 1 is stable on off-site power, normal configuration. All emergency systems are available. | ENS 57128 | Cook | 15 May 2024 08:27:00 | Unit 2 Manual Reactor Trip | The following information was provided by the licensee via email:
On May 15, 2024 at 0427 EDT, DC Cooks Unit 2 reactor was manually tripped due to difficulty maintaining steam generator water levels.
DC Cook Unit 2 had removed the main turbine from service at approximately 0354 EDT during a planned down-power to repair a steam leak on the high pressure turbine right outer steam/stop control valve upstream drip pot. Stable steam generator water levels were unable to be maintained. As a result, DC Cook Unit 2 was manually tripped with reactor power stabilizing at approximately 20 percent.
This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System actuation as a four hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight hour report.
The reactor trip was not complicated and all plant systems functioned normally. The DC Cook NRC Resident Inspector was notified. | ENS 57107 | Braidwood | 5 May 2024 08:38:00 | Automatic Reactor Trip Due to Lowering Steam Generator Water Level | The following information was provided by the licensee via email and phone:
At 0338 CDT, with the unit 1 in mode 1 at 6 percent power, the reactor automatically tripped due to lowering steam generator water level. The trip was uncomplicated with all systems responding normally post-trip. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for an actuation of the auxiliary feedwater system.
Operations responded using procedure 1BwEP-0 and stabilized the plant in mode 3. Decay heat is removed by steam dumps via the main condenser. 1A and 1B auxiliary feedwater pumps were actuated manually prior to the reactor trip in an attempt to restore steam generator water level. Unit 2 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.
- * * UPDATE ON 07/05/2024 AT 0450 EDT FROM MATTHEW WHITE TO TENISHA MEADOWS * * *
The following information was provided by the licensee via email and phone:
At 0338 CDT, with the unit 1 in mode 2 at 3 percent power, the reactor automatically tripped due to lowering steam generator water level. The trip was uncomplicated with all systems responding normally post-trip. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A) for an actuation of the auxiliary feedwater system, eight-hour notification.
Operations responded using procedure 1BwEP-0 and stabilized the plant in mode 3. Decay heat is being removed by steam dumps via the main condenser. 1A and 1B auxiliary feedwater pumps were actuated manually prior to reactor trip in an attempt to restore steam generator water level. Unit 2 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.
Notified R3DO (Hartman) | ENS 57075 | Beaver Valley | 13 April 2024 04:35:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
At 0035 EDT on April 13, 2024, with Unit 1 at 97 percent power, the reactor automatically tripped due to 1 of 3 reactor coolant pump (RCP) low flow reactor trip (signal) associated with a loss of the A and B 4160 volt normal buses. Auxiliary feedwater and the 1-1 emergency diesel generator (EDG) automatically started on valid actuation signals. The 1-1 EDG sequenced on to supply all required loads per plant design. All control rods fully inserted and the trip was not complex with all systems responding normally post-trip. Operators have responded and stabilized the unit in Mode 3 (Hot Standby). Decay heat is being removed by discharging steam to the main condenser via the condenser steam dump system with steam generators being supplied by the main feedwater system.
Unit 2 is not affected by the event.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
Due to the valid actuations of auxiliary feedwater and the 1-1 EDG, this event is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A).
There was no impact to the health and safety of the public or plant personnel. The NRC senior resident inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Power for the A-E Bus is on the 1-1 EDG. The D-F Bus is on offsite power. One electrical train of offsite power is down. |
|