| | Site | Start date | Title | Description |
|---|
| ENS 57124 | South Texas | 12 May 2024 21:41:00 | Automatic Reactor Trip | The following information was provided by the licensee via email and phone:
At 1641 CDT on May 12, 2024, with Unit 2 in Mode 1 at 15 percent power, the reactor automatically tripped due to a unit auxiliary transformer lockout. During the trip, all control rods fully inserted. The cause of the transformer lockout is currently unknown. Emergency diesel generator (EDG) 21 and 23 actuated and all three engineered safety feature (ESF) busses were energized.
All equipment responded as expected except for steam generator power operated relief valve (PORV) 2C which failed to open when required in automatic, and the load center (LC) E2A output breaker which failed to close automatically but was closed manually. Steam generator PORV 2C did open when placed in manual, although it subsequently failed to full open and was then closed. Primary system temperature and pressure are currently being maintained at 567 degrees/2235 psig following start of reactor coolant pumps 2A and 2D.
Due to the reactor protection system actuation (RPS) while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). This event is also being reported per 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of the emergency diesel generators. There was no impact to 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:
South Texas Project Unit 2 was in Mode 1 at 15 percent power due to performance of testing and analysis on the main turbine prior to the RPS actuation.
- * * UPDATE FROM ROBERT DEWOODY TO BRIAN P. SMITH ON MAY 22, 2024 AT 1805 EDT * * *
The following information was provided by the licensee via email and phone:
South Texas Project is submitting the following correction to the event notification:
The steam generator (SG) power operated relief valve (PORV) 2C did not fail to open automatically. System pressure during this event did not reach the automatic setpoint for the PORV (1225 psi), and there was no demand for it to open automatically. During the event, SG PORV 2C was taken to manual and it went full open when the up button was pushed slightly. It went closed when the down button was pressed to close it manually. In addition, the load center E2A output breaker initially failed to close automatically, however, after operations placed it in pull-to-lock and returned the hand switch to automatic, it closed automatically.
Notified R4DO (Dixon). | | ENS 57143 | Paragon Energy Solutions | 9 May 2024 04:00:00 | Part 21 - Defect with Emergency Diesel Generator Voltage Regulator | The following information was provided by Paragon Energy Solutions, LLC via email:
Paragon has identified a defect in one voltage regulator supplied to AEP DC Cook with serial number NLI-3S7950GR751A1-1007.
Pursuant to 10CFR Part 21 � 21.21(d)(3)(i), Paragon is providing initial notification of a defect associated with the emergency diesel generator (EDG) voltage regulator. The voltage regulator was refurbished under the client purchase order 01600229, project number 351030025. Part of the refurbishment involved complete replacement of the units wiring, physical inspection and testing of the unit to Paragon approved acceptance testing instructions. The refurbished unit was supplied to the customer in December 2023. Prior to installation (March 2024), the unit successfully passed bench testing at the plant. During post installation testing, the EDG was started, and the output voltage pegged high and was not controllable. DC Cook subsequently removed the voltage regulator and documented the non-conformance. DC Cook troubleshooting determined the unit was mis-wired. The unit (voltage regulator) was returned to Paragon, and inspection confirmed the plant's diagnosis. The identified mis-wire affects the system circuitry by placing silicon controlled rectifier 5CD in a reverse biased position. The reversed biased rectifier blocks the flow of current which creates an open circuit condition. This open circuit condition causes the output voltage to max out, and does not allow the output voltage to be adjusted. This condition, if left uncorrected, could contribute to a substantial safety hazard and is reportable in accordance with 10CFR Part 21.
Date of Discovery: May 9, 2024
Reportability Determined: May 23, 2024
Paragon has entered this condition in our corrective action program, and we have custody of the effected unit. The extent of condition is limited to this unit supplied to DC Cook. Paragon has determined there is no action necessary for DC Cook at this time.
Affected plant: DC Cook
- * * UPDATE ON 06/21/2024 AT 1655 EDT FROM RICHARD KNOTT TO ROBERT THOMPSON * * *
Paragon Energy Solutions submitted a final report for this event documenting the cause of the mis-wire and corrective actions to prevent recurrence.
Paragon contact: Richard Knott, Vice President Quality Assurance, Paragon Energy Solutions, LLC, 7410 Pebble Drive, Ft. Worth, TX 76118, 817-284-0077, rknott@paragones.com.
Notified R3DO (Havertape), R4DO (Josey), and Part 21 (email). | | ENS 57083 | LaSalle | 20 April 2024 12:04:00 | Automatic Actuation of Emergency Diesel Generators | The following information was provided by the licensee via phone and email:
At 0704 CDT on 4/20/24 with Unit 1 in Mode 1 at 100 percent power, an actuation of the emergency AC power system, specifically the Division 1 and Division 3 emergency diesel generators (EDGs) occurred during an unexpected loss of the Unit 1 system auxiliary transformer (SAT). The cause of the emergency AC power system auto-start was an unexpected loss of the Unit 1 SAT during switchyard maintenance. Bus 141Y did not fast transfer as designed resulting in the actuation of the Division 1 EDG. Division 3 EDG actuation is expected for this condition. The Division 1 and Division 3 EDGs automatically started as designed when the emergency AC power system valid actuation signal was received.
This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the emergency AC power system.
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:
Division 1 and Division 3 EDGs will remain in operation and loaded until the Unit 1 SAT is restored. This event resulted in the plant entering an unplanned 72 hour limiting condition for operation (LCO) in accordance with technical specification 3.8.1. The licensee is investigating the cause of the unexpected loss of the Unit 1 SAT and the failure of the bus 141Y fast transfer. | | 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. | | ENS 57047 | Palo Verde | 24 March 2024 23:34:00 | Valid Specified System Actuations of Unit 2 Train B Emergency Diesel Generator and Train B Auxiliary Feedwater | The following information was provided by the licensee via email:
At 1634 MST on March 24, 2024, an engineered safety features (ESF) service transformer deenergized resulting in a loss of power to the Unit 2 Train B 4.16 kV Class 1E Bus. The Unit 2 Train B emergency diesel generator (EDG) automatically started and energized the Unit 2 Train B 4.16 kV Class 1E Bus.
As a result of the loss of power on the Unit 2 Train B 4.16 kV Class 1E Bus and subsequent load sequencing after the Unit 2 Train B EDG started, the Unit 2 Train B auxiliary feedwater (AFW) pump automatically started as designed. The Train B AFW pump was not needed for steam generator level control and no auxiliary feedwater valves repositioned. The Train B AFW Pump did not supply feedwater to the steam generators.
All systems operated as designed. Per the emergency plan, no classification was required due to the event. Units 1, 2, and 3 remain in Mode 1 at 100 percent power. The 4.16 kV Class 1E Buses in Units 1 and 3 were not affected by the deenergization of the ESF service transformer.
The cause of the ESF service transformer being deenergized is under investigation.
This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of emergency AC electrical power systems and auxiliary feedwater system.
The NRC Resident Inspectors have been informed. | | ENS 57042 | Waterford | 22 March 2024 04:37:00 | Notification of Unusual Event Due to Fire in the Protected Area | The following information was provided by the licensee:
A Notification of Unusual Event, HU4.4 (see note below) was declared based a fire in the protected area requiring off site assistance to extinguish. The fire was in the main transformer yard. The fire was detected at 2328 CDT on March 21, 2024, and the fire was declared out at 0009 CDT on at March 22, 2024. An automatic reactor trip was initiated due to a loss of offsite power to the "B" train and a failure to automatically transfer from unit auxiliary transformer "B" to startup transformer "B.
The licensee notified State and local authorities and the NRC Resident Inspector.
The NRC remained in Normal.
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).
NOTE: Due to a typographical error initiating condition HU4.1 was initially recorded for the event. The correct initiating condition is HU4.4 as now shown.
- * * UPDATE AT 0345 EDT ON 03/22/24 FROM LARRY GONSALES TO BILL GOTT * * *
The licensee terminated the Notification of Unusual Event at 0221 CDT on 3/22/24.
The licensee notified the NRC Resident Inspector.
Notified R4DO (Gepford), IR-MOC (Grant), NRR-EO (Felts), 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 AT 0420EDT ON 03/22/24 FROM JOHN LEWIS TO BILL GOTT * * *
RPS ACTUATION
The following information was provided by the licensee via email:
On March 21, 2024, at 2328 CDT, Waterford 3 Steam Electric Station, Unit 3 was operating at 98 percent power when an automatic reactor trip was initiated due to a loss of offsite power to the B train and a failure to automatically transfer from unit auxiliary transformer B to startup transformer B.
Emergency feedwater actuation signal 2 (EFAS), safety injection actuation signal (ECCS), containment isolation actuation signal and emergency diesel generators automatically actuated. The unit is currently stable in Mode 3. All control rods fully inserted and all other plant equipment functioned as expected. Forced circulation remains with one reactor coolant pump per loop running. Decay heat removal is via the main condenser. A train safety bus is being supplied by off-site power, and B train safety bus is being supplied by emergency diesel generator B.
Following the loss of offsite power to the B train, it was reported that main transformer B and startup transformer B were both on fire. The Emergency Director declared an Unusual Event at time 2337 CDT. The fire was reported extinguished at 0009 CDT on March 22, 2024, and the Unusual Event was terminated at 0221 CDT on March 22, 2024. Offsite assistance was requested. The local fire department responded to the site but the fire was extinguished by the on-shift fire brigade. NRC Region IV management was contacted regarding the emergency plan entry at 0030 CDT on March 22, 2024.
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, ECCS, Containment Isolation and Emergency Diesel Generators.
The NRC Resident Inspector has been notified.
Notified R4DO (Gepford)
- * * RETRACTION OF NOTICE OF UNUSUAL EVENT FROM ON 03/26/24 AT 1721 FROM L. BROWN TO K. COTTON * * *
The initial notification in event notice #57042 by Waterford Steam Electric Station, Unit 3, reported a Notice Of Unusual Event (NOUE) emergency declaration due to a fire in the protected area requiring off site support to extinguish. The basis for retraction of the initial emergency notification is that this event did not meet the definition of a fire in the protected area that requires off site support to extinguish. Guidance provided in Nuclear Energy Institute (NEI) 99-01, Rev. 6 and implemented in Waterfords Emergency Plan procedure, initiating Condition HU4.4 states, The dispatch of an offsite firefighting agency to the site requires an emergency declaration only if it is needed to actively support firefighting efforts because the fire is beyond the capability of the Fire Brigade to extinguish. (NOTE: The Initial Notification Form sent from the Control Room at 2341 CDT on March 21, 2024, requested by and provided to the NRC Headquarter Operations Center via e-mail at 0302 CDT on March 22, 2024, stated that the Emergency Classification had been made on Initiating Condition HU4.4 rather than HU4.1)"
When the event occurred on March 21, 2024, the Emergency Director declared an Unusual Event at 2337 CDT and requested offsite support based on the information available at that time including the initial assessment by the fire brigade leader and expected need for offsite support to extinguish the fire. As reported in the 0420 EDT update on March 22, 2024, the fire was reported extinguished at 0009 CDT on March 22, 2024, by the Waterford Fire Brigade without the need of offsite support."
Notified R4DO (Kellar).
- * * UPDATE AT 1209 EDT ON 03/27/24 FROM JOHN LEWIS TO KAREN COTTON * * *
The initial notification in EN 57042 by Waterford Steam Electric Station, Unit 3, reported an emergency declaration of an Unusual Event due to a fire in the protected area requiring off site support to extinguish. The basis for the update to the initial notification is that this event did not meet the definition of a Fire in the Protected Area that requires offsite support to extinguish. As provided in NEI 99-01, Rev. 6 and implemented in Waterfords emergency plan procedure, initiating condition HU4.4 states, The dispatch of an offsite firefighting agency to the site requires an emergency declaration only if it is needed to actively support firefighting efforts because the fire is beyond the capability of the Fire Brigade to extinguish. Additionally, EAL 4.1 for a fire not extinguished within 15 minutes of detection in any Table H-1 fire area was not applicable because the fire did not occur in a Table H-1 fire area.
When the event occurred on March 21, 2024, the Emergency Director declared an Unusual Event at 2337 CDT and requested offsite support based on the information available at that time including the initial assessment by the fire brigade leader and expected need for offsite support to extinguish the fire. As reported in the 0420 EDT update on March 22, 2024, the fire was reported extinguished at 0009 CDT on March 22, 2024, by the Waterford Fire Brigade without the need of offsite support.
(NOTE: The Initial Notification Form sent from the Control Room at 2341 CDT on March 21, 2024, requested by and provided to the Headquarters Operation Center via e-mail at 0302 CDT on March 22, 2024, stated that the emergency classification had been made on initiating condition HU4.4 rather than HU4.1)
In accordance with NRC Approved guidance in FAQ 21-02 (ML21117A104), Waterford 3 is retracting the initial event notification made at 0117 EDT on March 22, 2024. The remaining events that were reported in EN 57042 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 (emergency feedwater) system, ECCS (emergency core cooling system), containment isolation and emergency diesel generators are still applicable and require no additional update at this time.
The licensee also provided a site map.
Notified R4DO (Kellar) | | ENS 57021 | Hatch | 11 March 2024 17:37:00 | Manual Reactor Trip | The following information was provided by the licensee via phone and email:
On March 11, 2024, at 1337 EDT, with Unit 1 in Mode 1 at 35 percent power performing power ascension activities, the reactor was manually tripped due to the 'A' reactor feed pump (RFP) tripping on low suction pressure. Due to the power level at the time, the 'B' RFP had not been placed in service. Closure of containment isolation valves (CIVs) in multiple systems and actuation of high-pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) occurred as a result of reaching the actuation setpoint on reactor water level as designed. The trip was not complex, with all safety systems responding normally post-trip. Operations responded and stabilized the plant. The 'B' RFP was placed in service and is controlling reactor water level. Decay heat is being removed by discharging steam to the main condenser using turbine bypass valves. Unit 2 is not affected.
Due to the emergency core cooling system (ECCS) discharging into the reactor, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A). Also, the Reactor Protection System actuation while critical is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of CIVs, RCIC and HPCI.
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 'A' RFP is under investigation. The reactor electric plant remains in a normal lineup with both emergency diesel generators available. There were no temperature or pressure technical specification limits approached. | | ENS 56997 | Calvert Cliffs | 28 February 2024 18:50:00 | Specified System Actuation - Automatic Start of Emergency Diesel Generators | The following information was provided by the licensee via phone and email:
At 1350 EST on 2/28/2024, with Calvert Cliffs Unit 1 in Mode 5 at 0 percent power and Unit 2 in Mode 1 at 65 percent power, an actuation of the '1A' and '2A' emergency diesel generators' auto-start occurred due to an undervoltage condition on the number 11 and number 21 4kV buses which are fed from the number 11 13kV bus. The '1A' and '2A' emergency diesel generators automatically started as designed when the 4kV buses' undervoltage signals were received.
This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of the '1A' and '2A' emergency diesel generators.
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 undervoltage condition was caused by the feeder breaker to the number 11 13 kV bus opening during electrical maintenance. | | ENS 56990 | Browns Ferry | 24 February 2024 08:19:00 | Automatic Start of Emergency Diesel Generator | The following information was provided by the licensee via phone and email:
At 0219 CST on February 24, 2024, Browns Ferry Unit 3 was shut down in a refueling outage, while closing 4 kV shutdown board breaker 3EB-9, the 4 kV shutdown board normal feeder breaker tripped open resulting in a valid 4 kV bus under-voltage condition. Due to the under-voltage condition, the 3B emergency diesel generator (EDG) auto started and tied to the board. The cause of the breaker tripping open is unknown and an investigation is in progress.
All systems responded as expected for the loss of voltage. This event requires an 8-hour report per 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 resident inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
No other safety related equipment was affected. The 3B EDG continues to supply the shutdown board pending further investigation. | | ENS 57072 | FitzPatrick | 22 February 2024 04:00:00 | Part 21 - Leaking Cylinder Liner in Emergency Diesel Generator | The following is a summary of the information provided by Engine Systems Inc. (ESI) via facsimile:
An EMD (Brand Name: Electro-Motive Diesel) cylinder liner developed a jacket water leak following installation on an emergency diesel generator set at the James A. Fitzpatrick Nuclear Power Plant. The leak occurred at a brazed joint and was detected after post-installation engine testing. Had the leak gone undetected, jacket water may have accumulated in the combustion chamber, airbox, and/or lubricating oil which could have eventually led to failure of the emergency diesel generator set.
ESI was the supplier of the EMD cylinder liner (part number: 9318833, serial number: 20D6294). The EMD cylinder was a component of a Blade Power Pack Assembly, part number: 40124898, serial number: 20L0603
Corrective Actions:
ESI will revise the dedication package to include additional verifications to prevent reoccurrence. The revision will be implemented within 30 days. Fitzpatrick returned the power assembly to ESI for replacement and no further action is required from Fitzpatrick.
Affected Plants:
Fitzpatrick. No other sites known to be affected.
The name and address of the individuals reporting this information is:
John Kriesel
Engineering Manager
Engine Systems, Inc.;
175 Freight Rd.
Rocky Mount, NC 27804
Dan Roberts
Quality Manager
Engine Systems, Inc.;
175 Freight Rd.
Rocky Mount, NC 27804 |
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