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| Entered date | Site | Region | Reactor type | Event description | |
|---|---|---|---|---|---|
| ENS 57141 | 24 May 2024 02:08:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via email: At 2223 CDT on May 23, 2024, with Quad Cities Unit 2 at 38 percent power, the reactor automatically tripped due to a turbine trip signal resulting in main stop valve closure, creating a valid reactor protection system signal. Reactor vessel level reached the low-level set-point following the scram, resulting in valid Group II and Group III containment actuation signals. The trip was not complex with all systems responding as expected 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 the Group II and Group III isolation. Operations responded using their emergency operating procedures and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 remains at 100 percent power. 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: Unit 2 was at a reduced power for maintenance. |
| ENS 57120 | 9 May 2024 21:10:00 | FitzPatrick | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: At 1629 EDT on 05/09/2024, the high pressure coolant injection (HPCI) system was declared inoperable due to a pinhole through-wall leak identified on the seal drain line for 23HOV-1 (HPCI trip throttle valve) downstream of the restricting orifice 23RO-137A. The location of the defect is in the class 2 safety related piping. HPCI is a single train safety system and this notification is being made in accordance with 10 CFR 50.72(b)(3)(v)(D). 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: This pinhole leak was discovered during normal operator rounds. Although HPCI is inoperable and in a 14 day limited condition of operation, the system function remains available. In addition, all other ECCS systems are currently operable. Compensatory measures (walkdowns) have been implemented to ensure the leak rate does not significantly increase. |
| ENS 57117 | 9 May 2024 14:42:00 | FitzPatrick | NRC Region 1 | The following is a synopsis of information provided by Engine Systems, Inc. (ESI) via fax and email: On February 22, 2024, an EMD brand cylinder liner developed a jacket water leak following installation on an emergency diesel generator set. 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 or airbox and potentially contaminated the engines lubricating oil. Jacket water intrusion into any of these areas is undesirable and could lead to failure of the diesel engine and therefore failure of the emergency diesel generator set. The extent of condition is a single cylinder liner, P/N 9318833, S/N 20D6294 used in the power assembly shown below. Customer: Constellation - Fitzpatrick Customer PO: 703, release 13498 ESI Sales Order: 3021545 Part Number Ordered: 40124898 (Blade Power Pack) Serial Number: 20L0603 ESI C-of-C Date: April 1, 2021 The corrective action: For Fitzpatrick: No action required; the power assembly has been returned to ESI for replacement. For ESI: ESI will revise the dedication package to include additional verifications to prevent reoccurrence. The revision will be implemented within 30 days. Name and contact information: Dan Roberts, Quality Manager Engine Systems Inc. 175 Freight Rd. Rocky Mount, NC 27804 John Kriesel, Engineering Manager Engine Systems Inc. 175 Freight Rd. Rocky Mount, NC 27804 | |
| ENS 57107 | 5 May 2024 08:11:00 | Braidwood | NRC Region 3 | Westinghouse PWR 4-Loop | 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. |
| ENS 57083 | 20 April 2024 13:51:00 | LaSalle | NRC Region 3 | GE-5 | 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 57072 | 12 April 2024 11:49:00 | FitzPatrick | NRC Region 1 | 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 | |
| ENS 57058 | 28 March 2024 01:52:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via email: At 2046 (CDT) on 3/27/24 with the unit 2 in Mode 5 at 0% power, an actuation of the Reactor Protection System occurred during testing of the scram discharge volume. The cause of the Reactor Protection System actuation was leakage of water into the scram discharge volume causing a high level condition while drains were isolated for testing. The Reactor Protection System automatically actuated as designed when the high scram discharge volume signal was received. All rods were previously fully inserted and the Control Rod Drive system was shutdown. No rod movement occurred due to the actuation. 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 Reactor Protection System. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 57050 | 25 March 2024 17:38:00 | Clinton | NRC Region 3 | GE-6 | The following information was provided by the licensee via email and phone call: At 1027 CDT on 3/25/24, it was determined that a contract supervisor tested positive in accordance with the fitness for duty testing program. The individuals authorization for site access has been terminated. The NRC Resident Inspector has been notified. |
| ENS 57004 | 3 March 2024 22:15:00 | Nine Mile Point | NRC Region 1 | GE-5 | The following information was provided by the licensee via email: On 3/3/24 at 1942 EST, while performing a plant shutdown in preparation for a refuel outage, Nine Mile Point Unit 2 experienced a reactor scram due to a main turbine trip on low condenser vacuum. The plant was at approximately 55 percent power at the time of the reactor scram. Additionally, following the scram a low RPV (reactor pressure vessel) level scram and containment isolation signal on level 3 was received, as expected. The containment isolation signal impacted RHR (residual heat removal) shutdown cooling, RHR letdown to radwaste, and RHR sampling. All impacted valves were closed at the time the isolation occurred. All control rods were fully inserted. Plant response was as expected. Post scram, the main turbine bypass valves are being used to control decay heat, and normal post scram level control is via the feed / condensate system. This is being report under 10 CFR 50.72(b)(2)(iv)(B), 'RPS Actuation', and 10 CFR 50.72(b)(3)(iv)(A), 'Specified System Actuation'. Unit 1 is not affected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The cause of the low condenser vacuum was a momentary loss of sealing steam. The condenser remained viable for decay heat removal. All safety equipment is available. The grid is stable with the plant in its normal shutdown electrical configuration. |
| ENS 56997 | 28 February 2024 17:46:00 | Calvert Cliffs | NRC Region 1 | CE | 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 56991 | 24 February 2024 18:08:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via email: At 1546 EST, with unit 2 at 100 percent power, the reactor was manually tripped due to the '22' steam generator feed pump tripping. 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). Operations responded using emergency operation procedure EOP-0, Post Trip Immediate Actions and EOP-1, Uncomplicated Reactor Trip and stabilized the plant in mode 3. Decay heat is removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected. ESFAS (engineered safety features actuation systems) actuation (auxiliary feedwater manual actuation) is reportable under 10 CFR 50.72(b)(3)(iv)(A) 8-hour report. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56980 | 19 February 2024 18:44:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: At 1045 EST, on 2/19/2024, during a maintenance activity, a loss of all reactor building ventilation occurred on Unit 2. With no flow past the ventilation radiation monitors, the radiation monitors were inoperable to support their ability to perform primary and secondary containment isolation functions or start the standby gas treatment system. Reactor building ventilation was restored within 15 minutes. Due to this inoperability, the radiation monitor system was in a condition that could have prevented fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector will be notified.
Upon further investigation, it was verified that the reactor building and the refueling floor radiation monitors are not needed to control the release of radiation for events described in chapter 14 of the updated Final Safety Analysis Report. For the analyzed loss of coolant accident (LOCA), the primary and secondary signals for this purpose were available and unaffected by this event. The radiation monitors provide a tertiary redundant method that is not credited within the station analysis. For all other analyzed accidents, the signal provided by the radiation monitors is not needed, as the secondary containment isolation function and start of the standby gas treatment system are not credited. Additionally, the fuel handling accident was not credible during the time of the event because no activities were in progress on the refueling floor. Therefore, the threshold for reporting the issue as an event or condition that could have prevented the fulfillment of a safety function was not met. The NRC Resident Inspector has been notified. Notified R1DO (Jackson) |
| ENS 56957 | 9 February 2024 15:07:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: On 2/9/24 at 1322 EST, it was determined that the unit was in an unanalyzed condition. A review of DC feeder circuit protection schemes identified a circuit for the fuel pool cooling system is uncoordinated due to inadequate fuse sizing. This results in a concern that postulated fire damage in one area could cause a short circuit without adequate protection, leading to the unavailability of equipment credited for in 10 CFR 50 Appendix R, Fire Safe Shutdown. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). The postulated event affects the following fire zones: fire areas 6S and 6N (within the Unit 2 reactor building). Compensatory actions for affected fire areas have been implemented. An extent of condition review is being performed. 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: Fire watches have been established in the affected areas. These will be maintained until the protection scheme is revised.
The following updated information was provided by the licensee via email and phone call: On 03/08/24 at 1418, extent of condition reviews identified circuit(s) in the Units 2 and 3 Reactor Protection Systems (RPS) which are also uncoordinated due to improper fuse sizing. These circuits are not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects the following fire areas: 32, 33, 38 and 39 (Units 2 and 3 Switchgear Rooms). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Arner)
On March 13, 2024, at 1350 EDT, extent of condition reviews identified a circuit in the Unit 2 reactor protection system (RPS) which is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50, Appendix R, Fire Safe Shutdown, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 57 (Switchgear Corridor, common to Units 2 and 3). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. Additionally, it was previously reported that fire area 6N contained a circuit which was not bounded by the Fire Safe Shutdown analysis; however, after further review it has been determined that compliance is maintained in this fire area and is therefore retracted from the scope of this report. The NRC Senior Resident Inspector has been notified. Notified R1DO (Jackson)
The following information was provided by the licensee via email: On 03/21/24 at 1211, extent of condition reviews identified an annunciator circuit for the Unit 3 emergency service water (ESW) and high pressure service water (HPSW) pump structure heating and ventilation panel that is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 47 (Unit 3 pump structure for `B' ESW and `3A'-`3D' HPSW pumps) and the yard fire area (Manhole 026D). In order to restore immediate compliance, the cable has been de-energized to eliminate the possibility of the event of concern. This circuit will remain de-energized or other measures will be implemented until the condition is permanently resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Ford) |
| ENS 56954 | 8 February 2024 17:59:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via email: A supervisor had a confirmed positive for alcohol during a random fitness for duty test. The supervisor's access to the plant has been terminated. |
| ENS 56939 | 30 January 2024 18:56:00 | Limerick | NRC Region 1 | GE-4 | The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: On January 30, 2024, a non-licensed employee supervisor, after investigation, was determined to be in involved with a controlled substance. The employee's access to the site has been placed on administrative hold, pending further investigation. The NRC Resident Inspector has been notified. |
| ENS 56936 | 29 January 2024 13:32:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: At approximately 1202 EST on 01/29/24, unit 2 experienced a reactor scram caused by a main turbine trip. Investigation is still ongoing. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: All control rods were fully inserted. The licensee indicated that the turbine trip may have been caused by a power load imbalance, however the cause of the incident is under investigation. The scram was not complex. Decay heat is currently being removed thru bypass valves dumping to the main condenser. Initially unit 2 lost the use of the bypass valves due to lack of condenser vacuum. Unit 2 used the high pressure coolant injection (HPCI) system in the condenser storage tank (CST) to CST mode to remove decay heat. Residual heat removal was used to keep the torus cool. Condenser vacuum was regained and unit 2 is back to removing decay heat with the turbine bypass valves. There was no impact to unit 3. The licensee confirmed there was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
The following information was provided by the licensee via email: Licensee adds 8-hour non-emergency 10 CFR 50.72(b)(3)(iv)(A) specified system actuation report to original 4-hour non-emergency 10 CFR 50.72(b)(2)(iv)(B) RPS Actuation report. At approximately 1202 EST on 01/29/24, unit 2 experienced a reactor scram by a main turbine trip. All control rods inserted. Reactor core isolation cooling system (RCIC) was manually initiated for level control. HPCI was manually initiated for pressure control. Primary containment isolation system (PCIS) Group II and III isolations occurred (specified system actuation). Investigation is ongoing. The NRC Resident Inspector has been notified. |
| ENS 56866 | 20 November 2023 17:53:00 | Dresden | NRC Region 3 | GE-3 | The following information was provided by the licensee via email: At 0956 (CST) on November 20, 2023, accumulated gas was identified in the Dresden Unit 2 high pressure coolant injection (HPCI) system discharge header. As a result, the HPCI system was declared inoperable. Since HPCI is a single-train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The HPCI system was subsequently vented, and the accumulated gas has been removed, restoring the Dresden Unit 2 HPCI system to an operable status. All other emergency core cooling systems remained operable during this time period. 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 licensee administratively verified the isolation condenser was operable after declaring HPCI inoperable as required by technical specifications. The licensee stated there was no increase in plant risk. The cause of gas accumulating in the Dresden Unit 2 HPCI discharge header is under investigation, and this issue has been entered into the licensees corrective action program.
Further analysis demonstrated that the Unit 2 high pressure coolant injection (HPCI) system remained operable with the level of voiding found in the HPCI discharge line. This analysis also found that the additional loads that would be present if the HPCI system were actuated with this level of voiding are within design limits of the HPCI system piping and supports. Based on these results, this event is not reportable under 10 CFR 50.72(b)(3)(v)(D), `Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Therefore, EN 56866 submitted on November 20, 2023, is being retracted. The NRC Resident Inspector has been notified. Notified R3DO (Havertape) |
| ENS 56865 | 19 November 2023 14:44:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via phone and fax: On November 18, 2023, the presence of alcohol was discovered inside the protected area. In accordance with the Constellation Fitness For Duty (FFD) Program, the individual has been escorted offsite and access to the plant denied pending the results of an investigation. This event is being reported under 10 CFR 26.719(b)(1) as it represents a significant FFD violation. The NRC Resident Inspector has been notified. |
| ENS 56856 | 16 November 2023 05:15:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via email: At 0227 EST on 11/16/23, Calvert Cliffs Unit 2 experienced an automatic trip from the reactor protection system (RPS) based on reactor trip bus undervoltage (UV). At that time, a loss of U-4000-22 (13 kV to 4 kV transformer) caused a loss of 22, 23, and 24 4 kV busses. This resulted in a loss of both motor generator (MG) sets causing the reactor trip bus UV. The loss of 22 and 23 4 kV non-safety related busses resulted in a loss of main feedwater. Auxiliary feedwater (AFW) was manually initiated and is feeding both steam generators. The 2B diesel generator (DG) started and restored the 24 4 kV safety related bus. Heat removal is via the normal turbine bypass valves to the main condenser. RPS actuation is reportable under 10 CFR 50.72(b)(2)(iv)(B) - 4 hour report ESFAS (engineering safety features actuation system) actuation (2B DG start on UV) is reportable under 10 CFR 50.72(b)(3)(iv)(A) - 8 hour report AFW operation is reportable under 10 CFR 50.73(a)(2)(iv)(A) - 60 day report 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: All rods fully inserted. There was no impact on Unit 1 operations. Unit 2 is stable in mode 3.
ESFAS actuation (AFW manual initiation) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8 hour report Notified R1DO (Defrancisco). |
| ENS 56841 | 8 November 2023 13:27:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via phone and email: At 0645 EST, on November 8, 2023, with Unit 2 in Mode 3 at zero percent power, a manual actuation of the auxiliary feedwater system (AFW) occurred during a planned plant cooldown. The reason for the AFW manual-start was a trip of the 22 steam generator feed pump due to a high casing level. The 23 AFW motor driven pump was manually started in accordance with implementation of AOP-3G, Malfunction of Main Feedwater System to restore steam generator levels. There was no impact to Unit 1. 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 AFW 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: No other systems were affected. No other compensatory or mitigation strategies implemented. Plant cooldown was the only significant evolution in progress. No impact to other technical specifications or limiting conditions for operation. All systems functioned as required. The electric plant is being supplied by offsite power with all diesel generators available. No significant increase in plant risk. There was nothing unusual or not understood. |
| ENS 56839 | 7 November 2023 18:42:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via email: At 1617 on 11/7/2023, Calvert Cliffs Unit 2 experienced an automatic trip from a Reactor Protection System (RPS) based on reactor trip bus under voltage (UV). At that time a loss of U-4000-22 caused a loss of 22, 23, and 24 4kV busses. This resulted in a loss of both motor generator (MG) sets causing the reactor trip bus UV condition. The loss of 22 and 23 4kV non-safety related busses resulted in a loss of main feedwater. Auxiliary feedwater (AFW) was manually initiated and is feeding both steam generators. The 2B diesel generator (DG) started and restored the 24 4kV safety related bus. Heat removal is via the normal turbine bypass valves to the main condenser. RPS actuation is reportable under 10 CFR 50.72(b)(2)(iv)(B) - 4-hour report. ESFAS actuation (2B DG start on UV) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. ESFAS actuation (AFW manual initiation) is reportable under 10CFR50.72(b)(3)(iv)(A) - 8-hour report. Site Senior NRC resident inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Unit 1 was unaffected. Estimation of duration of shutdown is 24 hours. |
| ENS 56822 | 30 October 2023 17:06:00 | FitzPatrick | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone call and email: A non-licensed supervisory employee had a confirmed positive test during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. |
| ENS 56810 | 22 October 2023 01:43:00 | Nine Mile Point | NRC Region 1 | GE-2 | The following information was provided by the licensee via phone and email: On October 21, 2023, at 2048 EDT, reactor recirculation pump (RRP) 12 tripped. The cause for the trip is under investigation. Following the RRP trip, the average power range monitors (APRMs) flow bias trips were inoperable due to reverse flow through RRP 12. The APRMs were restored to operable on October 21, 2023, at 2058 EDT, when the RRP 12 discharge blocking valve was closed. This 8-hour non-emergency report is being made based upon requirements of 10CFR50.72(b)(3)(v)(A) which states: "Licensee shall notify the NRC of any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: (A) Shut down the reactor and maintain it in a safe shutdown condition." The NRC Resident Inspector has been notified. |
| ENS 56790 | 12 October 2023 23:31:00 | Ginna | NRC Region 1 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On 10/12/23 at 2127 EDT, with the Unit 1 in Mode 1 at 100% Power, operators identified degrading condenser vacuum and manually tripped the reactor. All control rods inserted as expected. The trip was not complex, and all systems responded normally post-trip. The cause of the degraded condenser vacuum was an unexpected closure of the condenser air ejector regulator. The cause of the air ejector regulator going closed is not fully understood and is being investigated. Following the SCRAM, Operators responded and stabilized the plant. Decay heat is being removed by the Main Steam System through the Atmospheric Relief Valves (ARVs) and Auxiliary Feed Water (AFW) systems. Due to the Reactor Protection System (RPS) 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 a valid specified system actuation. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56753 | 21 September 2023 10:31:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: A licensed operator had a confirmed positive test for alcohol during another entity's pre-access fitness-for-duty screening for unescorted access authorization. The individual's unescorted access at Peach Bottom Atomic Power Station has been denied. The NRC Resident Inspector has been notified. |
| ENS 56745 | 18 September 2023 23:26:00 | Clinton | NRC Region 3 | GE-6 | The following information was provided by the licensee via email: On 9/18/2023 at 2007 CDT, Clinton reported to the Illinois Emergency Management Agency, National Response Center and DeWitt County a hazardous substance release of 1300 gallons of Sodium Bisulphite. The release was at the site's flume discharge building due to a crack on a fitting inside the building. This release did not exceed any NRC regulations or reporting criteria. This notification is being made solely as a four-hour, non-emergency notification for a Notification of Other Government Agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56731 | 9 September 2023 15:35:00 | Ginna | NRC Region 1 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On 9/9/23 at 1143 EDT, with the Unit 1 in Mode 1 at 100 percent power, all 4 turbine control valves closed resulting in a reactor protection system (RPS) automatic reactor trip on over temperature differential temperature. All control rods inserted as expected. The trip was not complex and all systems responded normally post-trip. The cause of the control valve closure has not been determined. Following the SCRAM, operators responded and stabilized the plant. Decay heat is being removed by the main steam system through the atmospheric relief valves and auxiliary feed water systems. Due to the RPS 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 a valid specified system actuation. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56710 | 2 September 2023 09:46:00 | Nine Mile Point | NRC Region 1 | GE-5 | The following information was provided by the licensee via email: On 9/2/2023 at 0632 EDT, a feedwater transient occurred resulting in an reactor protection system (RPS) automatic reactor scram on low level (Level 3, 159.3 inches). Following the scram, reactor water level dropped below Level 2 (108.8 inches) resulting in a Group 2 recirculation sample system isolation, Group 3 traveling in-core probe (TIP) isolation valve isolation, Group 6 and 7 reactor water cleanup isolation, and Group 9 containment purge isolations. All control rods inserted as expected. High pressure core spray and reactor core isolation cooling initiated and injected as expected. ECCS systems have been secured and normal reactor pressure and level control has been established for hot shutdown. Nine Mile Point Unit 2 is stable and in Mode 3. These 4 hour and 8 hour non-emergency reports are being made in accordance with 10 CFR 50.72(b)(2) (iv)(A), 10 CFR 50.72(b)(2)(iv)(B), and 10 CFR 50.72(b)(3)(iv)(A). The NRC Resident was informed. There was no impact on Unit 1. |
| ENS 56698 | 25 August 2023 23:39:00 | Byron | NRC Region 3 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: At approximately 1600 CDT on 8/25/2023, a partial loss of the commercial phone communications system occurred that affects the emergency notification system (ENS) and the functionality of an emergency response facility. This is an eight-hour, non-emergency notification of a loss of emergency assessment capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii). Communications via alternate methods were subsequently established. The telecommunications provider has not provided an estimated repair time. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56676 | 11 August 2023 08:03:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via phone and email: At 0329 (CDT) on August 11, 2023, with Unit 2 in Mode 1 at 90 percent power, the reactor automatically tripped due to a turbine trip. The trip was uncomplicated with all systems responding normally post-trip. The cause and details of the event are under investigation. Containment isolation valves actuated closed in multiple systems on a valid Group II signal. 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 the Group II isolation. Operations responded using the emergency operating procedure and stabilized the plant in Mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 is not affected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56667 | 8 August 2023 17:03:00 | FitzPatrick | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: A licensed (non-active) individual failed to comply with fitness for duty testing policies. The individual's unescorted access was terminated. |
| ENS 56652 | 3 August 2023 16:58:00 | Nine Mile Point | NRC Region 1 | GE-2 | The following information was provided by the licensee via email: A licensed employee had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Senior Resident Inspector was notified. |
| ENS 56606 | 3 July 2023 17:03:00 | Quad Cities | NRC Region 3 | GE-3 | The following information was provided by the licensee via phone and email: At 1530 (EDT) on July 3, 2023, Constellation Generation Company, LLC reported to the Illinois Environmental Protection Agency and the Illinois Emergency Management Agency and Office of Homeland Security (IEMA-OHS) that tritium concentrations in existing monitoring wells in a known (10 CFR) 50.75(g) recovery area were found higher than normal (at Quad Cities Nuclear Generating Station). This higher than normal tritium concentration did not exceed any NRC regulations or reporting criteria and there is no indication of a liquid release beyond the site boundary. This notification is being made solely as a four-hour, non-emergency notification for a notification of other government agency in accordance with 10 CFR 50.72(b)(2)(xi). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56576 | 15 June 2023 09:35:00 | Byron | NRC Region 3 | Westinghouse PWR 4-Loop | The following is a summary of information provided by the licensee via email: A non-licensed, non-supervisory employee was identified bringing a prohibited item into the protected area. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. |
| ENS 56560 | 6 June 2023 13:19:00 | Three Mile Island | NRC Region 1 | B&W-L-LP | The following information was provided by the licensee via email: At 0937 EDT on June 6, 2023, it was discovered that a site employee suffered a non-work-related fatality. The individual was found non-responsive outside the Radiological Controlled Area. This is a four-hour, non-emergency notification for which a notification to other government agencies has been made. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). The NRC Region I inspector has been notified. |
| ENS 56559 | 5 June 2023 21:58:00 | Ginna | NRC Region 1 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: At 1823 EDT, the shift manager was notified that one siren, part of the public notification system (siren number 10), spuriously activated for approximately one minute. Monroe County agencies were notified regarding the actuation. The cause of the actuation is being investigated and the ability for the siren to actuate has been removed until the cause is determined. There is no impact to the emergency planning zone. This event is a four-hour, non-emergency report for notification to other government agencies in accordance with 10 CFR 50.72(b)(2)(xi). |
| ENS 56513 | 9 May 2023 17:41:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: At 1455 (EST) on Tuesday May 9, 2023, Peach Bottom Atomic Power Station (PBAPS) technical support center (TSC) ventilation system lost power. Power loss was caused by a tree down on the 361 transmission line. Power was not able to be restored within an hour. At 1639 (EST), power was restored to TSC ventilation, and capability was restored. This report is being submitted pursuant to 10 CFR 50.72(b)(3)(xiii) as a major loss of emergency preparedness capabilities due to a reduction in the effectiveness of the onsite TSC. NRC Resident has been notified. |
| ENS 56502 | 4 May 2023 10:27:00 | Limerick | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: A non-licensed, non-supervisor contractor was found to be in possession of alcohol in the protected area. The individual's site access has been terminated. The NRC Senior Resident Inspector has been notified. |
| ENS 56471 | 17 April 2023 09:37:00 | LaSalle | NRC Region 3 | GE-5 | The following information was provided by the licensee via email: At 0246 CDT on April 17, 2023, it was discovered that the single train low pressure core spray system was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). All other emergency core cooling systems remained operable during this time period. 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: LaSalle Unit 1 is in a 7 day limiting condition for operation. |
| ENS 56464 | 11 April 2023 11:05:00 | Limerick | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid specific system actuation of the Emergency Service Water (ESW) System. On 2/16/2023, while performing a calibration planned maintenance (PM) for a jacket water pressure indicator during a D13 diesel generator system outage window, the 'C' ESW pump unexpectedly auto-started. Subsequent investigation identified that the affected jacket water pressure indicator shares a common sensing line with a jacket water pressure switch that provides a back-up to the engine speed switch for the engine running signal. At the time the jacket water pressure indicator calibration PM was being performed, the power circuits for D13 diesel generator instrumentation were energized. Pressurization of the energized jacket water pressure switch during the pressure indicator calibration activity resulted in initiation of a false engine running signal to the `C' ESW pump start logic. This event is considered an invalid system actuation because the 'C' ESW pump started in response to a false signal that the D13 EDG was running when the D13 EDG did not start. The actuation was not initiated in response to actual plant conditions or parameters and was not a manual initiation. The ESW system functioned as expected in response to the actuation. The affected ESW pump was shut down in accordance with plant procedures. There was no impact on the health and safety of the public or plant personnel. The licensee notified the NRC Resident Inspector. |
| ENS 56421 | 18 March 2023 19:07:00 | Nine Mile Point | NRC Region 1 | GE-2 | The following information was provided by the licensee via email: On 3/18/2023 at 1410 EDT, with Nine Mile Point Nuclear Station Unit 1 in a planned refueling outage, the main control room was notified of the results of an automated examination of a dissimilar metal weld on reactor penetration N2E. The results indicate a defect present which cannot be found acceptable under ASME Section XI, IWB-3600. This 8-hour non-emergency report is being made based upon requirements of 10CFR50.72(b)(3)(ii)(A) which states, `The licensee shall notify the NRC ... of the occurrence of ... any event or condition that results in: (A) The condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.' The NRC Senior Resident was informed. A repair plan is being developed. |
| ENS 56389 | 4 March 2023 16:42:00 | LaSalle | NRC Region 3 | GE-5 | The following information was provided by the licensee via email: At 0910 (CST), with Unit 2 in Mode 4 at 0 percent power, an actuation of a reactor scram on low charging water header pressure occurred during restoration from hydrostatic test conditions. All control rods were already fully inserted prior to the receipt of the scram signal. 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 Unit 2 RPS system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56386 | 3 March 2023 09:48:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via phone and email: A non-licensed supervisor tested positive in accordance with the FFD (fitness-for-duty) testing program. The individual's authorization for site access has been terminated. The NRC Senior Resident Inspector has been notified. |
| ENS 56373 | 19 February 2023 08:56:00 | FitzPatrick | NRC Region 1 | GE-4 | The following information was provided by the licensee via fax or email: At 0105 EST on February 19, 2023, with the James A. FitzPatrick Nuclear Power Plant (JAF) at 100 percent power, a valid high main steam line radiation signal was received. An actuation of a fire protection foam system caused migration of high conductivity water into a low conductivity sump. Organic compounds were introduced into the primary coolant and resulted in a temporary increase in nitrogen-16 which was detected by main steam line radiation monitors and actuated primary containment isolation signals in more than one system. The reactor water recirculation sample system isolated. The signal also went to the normally isolated main steam line drain system and condenser air removal system. The event is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). The elevated radiation condition no longer exists. Health and safety of the public was not impacted by this event. The NRC Resident Inspector was notified. |
| ENS 56352 | 16 February 2023 13:26:00 | Braidwood | NRC Region 3 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |
| ENS 56347 | 9 February 2023 15:40:00 | Calvert Cliffs | NRC Region 1 | CE | The following information was provided by the licensee via email: This 60-day optional telephone notification is being made in lieu of an LER (Licensee Event Report) submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 0637 EST on December 25, 2022, the 2B EDG inadvertently started and ran unloaded without a valid undervoltage or safety injection actuation signal. It was determined that this condition was caused by the failure of the emergency start button due to age-related degradation. The button is normally held depressed (closed) by the glass enclosure in standby. To start the EDG using the Emergency Start Button, the button is released (open) when the glass enclosure is broken, which sends a start signal to the EDG. During troubleshooting, the resistance across the button contacts was measured at zero volts DC, indicating the button had failed to an open state causing the EDG to start. The button fell apart when the glass enclosure was removed. The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the emergency diesel generator. The NRC Resident Inspector has been notified. |
| ENS 56356 | 6 February 2023 13:26:00 | Clinton | NRC Region 3 | GE-6 | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |
| ENS 56359 | 6 February 2023 13:26:00 | Nine Mile Point | NRC Region 1 | GE-5 GE-2 | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |
| ENS 56363 | 6 February 2023 13:26:00 | Ginna | NRC Region 1 | Westinghouse PWR 2-Loop | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |
| ENS 56358 | 6 February 2023 13:26:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |