Semantic search
| Entered date | Site | Region | Reactor type | Event description | |
|---|---|---|---|---|---|
| ENS 57026 | 13 March 2024 02:29:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via phone and email: On March 12, 2024, at 2111 EDT, a valid containment ventilation isolation train 'A' and 'B' signal was received due to a spurious loss of power to 1EMF-38 (containment particulate radiation monitor) and 1EMF-39 (containment gas radiation monitor). The power to 1EMF-38 and 1EMF-39 was restored. 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: There were no plant evolutions ongoing at the time of the event and the cause of the loss of power is under investigation. There was no impact to Unit 2.
After further review of the event, it was determined the actuation of the associated containment ventilation isolation train 'A' and 'B' was not valid. This is due to the loss of power being associated with the control room modules for 1EMF-38 and 1EMF-39, and not a result of an actual sensed parameter or plant condition. Therefore, this event notification is being retracted. The NRC Resident Inspector has been notified. Notified R2DO (Miller) |
| ENS 56988 | 22 February 2024 08:55:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via phone and email: This 60-day optional telephone notification is being made in lieu of a Licensee Event Report (LER) 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 0815 EST on December 28, 2023, an invalid actuation of the four emergency diesel generators (EDGs) occurred. It was determined that this condition was likely caused by spurious operation of the undervoltage relay for the startup auxiliary transformer feeder breaker to the `1D' balance of plant bus which was being fed by the unit auxiliary transformer at the time, per the normal lineup. This non-safety related EDG actuation logic was disabled, and additional investigation is planned during the upcoming refueling outage. 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 system. Therefore, this event has been determined to be an invalid actuation. During this event, the four EDGs functioned successfully, and the actuations were complete. All emergency buses remained energized from offsite power and, therefore, the EDGs did not tie to their respective buses. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector had been notified. |
| ENS 56987 | 22 February 2024 08:55:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via phone and email: This 60-day optional telephone notification is being made in lieu of a Licensee Event Report (LER) 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 2333 EST on January 1, 2024, an invalid actuation of group 6 primary containment isolation valves (PCIVs) (i.e., containment atmospheric control/monitoring (CAC/CAM) and post-accident sampling system (PASS) isolation valves) occurred. Reactor building ventilation isolated and standby gas treatment started per design. No manipulations associated with the isolation or reset logic were ongoing at the time. Troubleshooting determined that the group 6 isolation signal resulted from spurious relay contact actuation in the main stack radiation high-high isolation logic due to relay contact oxidation. The main stack radiation monitor is a shared component that sends isolation signals to Unit 1 and Unit 2. There were no Unit 1 actuations. Only the relay contacts associated with Unit 2 actuated. The relay has been replaced. 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 system. Therefore, this event has been determined to be an invalid actuation. During this event the PCIVs functioned successfully, and the actuations were complete. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector had been notified. |
| ENS 56977 | 19 February 2024 03:34:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via phone and email: At approximately 2325 EST on February 18, 2024, with Unit 1 in Mode 5 at 0 percent power and Unit 2 in Mode 1 at 100 percent power, emergency diesel generator 2 automatically started due to the unexpected loss of AC power to emergency bus E2 during a planned transfer of E2 DC control power from normal to alternate for the 1B-1 battery. In addition, the unexpected loss of AC power to E2 resulted in Unit 1 primary containment isolation system (PCIS) partial Group 2 (i.e., drywell equipment and floor drain, residual heat removal (RHR), discharge to radioactive waste, and RHR process sample), Group 6 (i.e., containment atmosphere control/dilution, containment atmosphere monitoring, and post accident sampling systems), and partial Group 10 (i.e., air isolation to the drywell) isolations. Emergency diesel generator 2 automatically started and re-energized the E2 bus as designed when the loss of E2 signal was received. The PCIS actuations were as expected for the outage plant line up on Unit 1 at the time. The cause of the loss of electrical power to emergency bus E2 is under investigation at this time. 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 diesel generator 2 and PCIS. 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: This event will be entered into the plant's corrective action program. |
| ENS 56974 | 17 February 2024 14:07:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via email and phone call: At 0837 EST, on 02/17/2024, during a refueling outage at 0 percent power while performing local leak rate testing (LLRT) on the reactor core isolation cooling (RCIC) isolation valves, which is part of the containment boundary, it was determined that the Unit 1 primary containment leakage rate did not meet 10 CFR 50 Appendix J requirements specified in Technical Specification 5.5.12. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56864 | 19 November 2023 00:53:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via phone and email: At 2138 EST on November 18, 2023, Harris Nuclear Plant notified the National Response Center of a biodegradable oil leak that entered the Harris Lake. The North Carolina Department of Environmental Quality will also be notified of this condition on November 19, 2023. The oil leak was less than one gallon and came from a temporary pump. The leak has stopped, and spill cleanup is underway. This condition did not violate any NRC regulations or reporting criteria. This notification is being made solely as a four-hour, non-emergency notification for a notification to another 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 56858 | 16 November 2023 12:12:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via phone and email: At 0906 Eastern Standard Time (EST) on November 16, 2023, it was determined that a non-licensed employee supervisor failed a test specified by the Fitness for Duty (FFD) testing program. The individual's authorization for site access has been removed. The NRC Resident Inspector has been notified. |
| ENS 56830 | 3 November 2023 15:27:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via email: A press conference is being held by the Oconee County Sheriff's office today at 1530 EDT in which Duke Energy will be present and may participate regarding the facts pertaining to an event that occurred outside the Oconee Nuclear Power Plant. The NRC Resident Inspector was notified. This is a four-hour report per 10 CFR 50.72(b)(2)(xi) for any event or situation for which a news release is planned or notification to other government agencies has been or will be made which is related to heightened public or government concern. The event is not significant with respect to the health and safety of the public. |
| ENS 56802 | 18 October 2023 15:18:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On October 18, 2023, at 1116 (EDT), with Unit 1 in Mode 5, an automatic actuation of the 1A auxiliary feedwater motor driven pump occurred when an incorrect action resulted in an automatic start 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 auxiliary feedwater system. Feedwater is not needed for plant conditions, and the 1A auxiliary feedwater pump did not feed the steam generators. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56797 | 15 October 2023 23:30:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee: At 2256 EDT on October 15, 2023, Brunswick declared a Notification of Unusual Event due to a fire not extinguished within 15 minutes. The licensee received fire alarms and indication of a halon discharge in the basement of the emergency diesel generator building. Due to the delay in the entry into the area, the licensee was not able to verify that the fire was out within 15 minutes. Upon entry into the room, the licensee noted an acrid odor near a transformer, but there was not a fire in the room. The fire was declared out at 2310 EDT. The licensee notified the NRC 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).
The following information was provided by the licensee via email: Termination of Unusual Event due to verification of no fire in the basement of the emergency diesel generator building." The licensee terminated the Unusual Event at 0045 on 10/16/23. The licensee notified the NRC Resident Inspector. Notified R2DO (Miller), IR-MOC (Grant), NRR-EO (Felts), DHS-SWO, FEMA Ops Center, CISA Central, FEMA NWC (email), CWMD Watch Desk (email), DHS NRCC THD Desk (email), and DHS Nuclear SSA (email). |
| ENS 56714 | 5 September 2023 17:05:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: A non-licensed contract supervisor had a confirmed positive for illegal drugs during a random fitness-for-duty test. The contract supervisor's access to the plant has been terminated. |
| ENS 56585 | 22 June 2023 13:50:00 | Robinson | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: At 1035, on June 22, 2023, with Unit 2 in Mode 1 at 100% power, the reactor automatically tripped due to `A' train reactor trip breaker and `B' train reactor trip bypass breaker opening during testing. The trip was not complex, with all systems responding normally post-trip. MST-021 (Reactor Protection Logic Train `B' At Power) testing was in progress at the time of trip. Operations responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. 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). As a result of the reactor trip, emergency feedwater actuated; therefore, this event is being reported as an eight-hour, non-emergency notification per 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. |
| ENS 56478 | 20 April 2023 05:24:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via phone and email: At 0148 Eastern Daylight Time (EDT) on April 20, 2023, with Unit 1 in Mode 1 at 100% power, the reactor automatically tripped due to a turbine trip. Turbine Bypass valves did not open on the trip due to Turbine Protection system power supply failure; the Safety Relief Valves (SRVs) opened automatically to control reactor pressure. Reactor Pressure reached approximately 1095 psig on the trip; exceeding the 1060 psig RPS trip setpoint. Operations responded and stabilized the plant. Operations was able to transition from SRVs to main steam line drains to the condenser. Reactor water level is being maintained via the Condensate / Feedwater system. Decay heat is being removed by discharging steam to the main condenser using the main steam line drains. 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). Reactor water level reached low level 1 (LL1) following the reactor trip. The LL1 signal causes Group 2 (i.e., floor and equipment drain isolation valves), Group 6 (i.e., monitoring and sampling isolation valves), and Group 8 (i.e., shutdown cooling isolation valves) isolations. The LL1 isolations occurred as designed; the Group 8 valves were closed at the time of the event. Due to the valid Primary Containment Isolation System (PCIS) actuation and RPS actuation from the reactor pressure signal, this event is also being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A). Unit 2 is not affected by this event. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56451 | 2 April 2023 11:29:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On April 2, 2023, at 0341 EDT, with Unit 2 in Mode 3 and the 2B main feedwater pump feeding the steam generators, the 2A main feedwater pump recirculation valve, 2CF-76, failed. Further, observation of the operating 2B main feedwater pump recirculation valve, 2CF-81, called into question its functionality. At 0352 EDT, operations manually started the auxiliary feedwater motor driven pumps to feed the stream generators to allow maintenance on the main feedwater system. The auxiliary feedwater motor driven pumps started as designed. Flow to the steam generator was not adversely impacted during this sequence. 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 auxiliary feedwater system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56366 | 16 February 2023 11:33:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On February 16, 2023 at 0859 EST, a contract worker at McGuire was transported off-site for treatment at an off-site medical facility. Upon arrival at the off-site medical facility, medical personnel declared the individual deceased at 0915 EST. The fatality was not work-related and the individual was inside the Radiologically Controlled Area. An on-site survey confirmed that neither the individual nor the individual's clothing were contaminated. A notification will be made to the Occupational Safety and Health Administration. This is a four-hour notification, non-emergency for an on-site fatality and notification of other government agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). The NRC Resident Inspector has been notified. |
| ENS 56345 | 9 February 2023 14:53:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: This 60-day optional telephone notification is being made in lieu of a Licensee Event Report as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to 10 CFR 50.73(a)(2)(iv)(A) for an invalid system actuation. On January 1, 2023, at approximately 0604 EST, static inverter KXA failed causing a loss of power to shared 120-VAC auxiliary control panel board KXA. Operations entered the appropriate procedures to assist in diagnosing and responding to the event. As expected, the solenoid valves in the instrument lines to steam supply valves 1SA-48ABC and 1SA-49AB deenergized, causing 1SA-48ABC and 1SA-49AB to open and admit steam to the unit 1 turbine driven auxiliary feedwater pump (TDAFWP). Operations reduced turbine load to maintain reactor power less than 100 percent. At approximately 0641 EST, power was restored to the KXA panelboard and the TDAFWP was secured. All systems functioned as required. Actuation of the TDAFWP was not initiated in response to actual plant conditions or parameters satisfying the requirements for initiation of the system nor was the actuation due to an intentional manual initiation. Therefore, this actuation is considered an invalid actuation. The NRC Resident Inspector has been notified. |
| ENS 56316 | 19 January 2023 13:20:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On 01/19/23 at approximately 1000 EST, the emergency sirens in Catawba County, Gaston County, Iredell County, Lincoln County, and Mecklenburg County were inadvertently activated by an offsite agency during a planned silent test. The sirens are in the McGuire Emergency Planning Zone (EPZ). Duke Energy notified the state and all counties within the EPZ. Mecklenburg County has issued a press release. This is a four-hour notification, non-emergency for a notification of other government agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). The NRC Resident Inspector has been notified. |
| ENS 56287 | 28 December 2022 09:18:00 | Brunswick | NRC Region 2 | GE-4 | 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 0906 Eastern Time (EST) on November 9, 2022, an invalid actuation of Group 6 Primary Containment Isolation Valves (PCIVs) (i.e., Containment Atmospheric Control/Monitoring and Post Accident Sampling isolation valves) occurred. In addition, per design, Reactor Building Ventilation isolated and Standby Gas Treatment started. It was determined that this condition was caused by faulty test equipment that was being used during preparation for the Main Stack Radiation Monitor High Radiation Response Time test. This test requires connecting a recording device to monitor for the test start signal on a Unit 2 relay associated with the Main Stack High Radiation signal. The recorder faulted which caused the associated fuse to blow and resulted in Unit 2 receiving a Main Stack High Radiation signal and Group 6 PCIV actuation. It was verified that the radiation monitor was not in trip electrically (i.e., there was no high radiation condition). 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 system. Therefore, this event has been determined to be an invalid actuation. During this event the PCIVs functioned successfully, and the actuations were complete. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector was notified. |
| ENS 56281 | 19 December 2022 13:12:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via email: At 0735 EST on December 19, 2022, it was determined that a non-licensed employee supervisor failed a test specified by the Fitness-for-Duty (FFD) testing program. The individual's authorization for site access has been terminated. The NRC Resident Inspector has been notified. |
| ENS 56221 | 14 November 2022 13:05:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via email: During a scheduled refueling outage, a walkdown inside containment discovered a small amount of boron on the 1B2 Reactor Coolant Pump (RCP) lower bearing temperature instrument. At 0730 EST on November 14, 2022, with Unit 1 in Mode 6, disassembly of the instrument indicated the source of the boron was from a leak in the thermowell. The thermowell is considered part of the reactor coolant system pressure boundary and as such the condition is reportable. Repairs for the condition are in progress. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56197 | 1 November 2022 16:56:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via email: At 1433 EDT on November 1, 2022, it was determined that a single relevant indication in the RCS pressure boundary did not meet the acceptance criteria under ASME, Section XI IWB-3514-2. 'Allowable Planar Flaws.' The condition will be resolved prior to plant startup. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56190 | 31 October 2022 00:40:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: At 2057 Eastern Daylight Time (EDT), with Unit 1 in Mode 3 at 0 percent power, an actuation of the Auxiliary Feedwater (AFW) System occurred during an attempt to start the 'B' Main Feed Pump. The reason for the AFW system auto-start was due to the 'A' electrical bus being under clearance and the 'B' Main Feed Pump not starting, resulting in a valid actuation signal for loss of both Main Feedwater pumps. The 'A' and 'B' motor-driven AFW (MDAFW) pumps were running prior to the attempted start of the B Main Feedwater pump and continued to run. The MDAFW Flow Control Valves (FCVs) went full open automatically as designed when the MDAFW 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 AFW System. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56189 | 30 October 2022 09:43:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: At 0653 Eastern Daylight Time (EDT), with Unit 1 in Mode 1, at 16 percent power, an automatic reactor trip occurred due to an under-voltage condition on the 'A' reactor coolant pump (RCP) and the 'C' RCP. Power was lost from the 'A' auxiliary bus while performing an operating procedure to transfer power from the 'A' start-up transformer to the 'A' unit auxiliary transformer. Operations responded and stabilized the plant. Decay heat is being removed by the main steam system to the atmosphere using the steam generator power-operated relief valves. 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). 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 auxiliary feedwater system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56186 | 28 October 2022 02:24:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: At 2050 EDT (on October 27, 2022), with Unit 1 in Mode 3, it was discovered that all auxiliary feedwater pumps were simultaneously inoperable and the capability to supply the 'B' steam generator was not maintained; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The function of the auxiliary feedwater pumps to supply the 'A' steam generator and 'C' steam generator was maintained. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56177 | 24 October 2022 11:40:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On 10/24/2022 at 0857 EDT, with Unit 2 in Mode 1 at 7 percent power, the reactor was manually tripped due to a 2B train main feedwater pump trip. The trip was not complex, with all systems responding normally post-trip. The auxiliary feedwater (AFW) system started automatically as expected. Operations responded and stabilized the plant. Decay heat is being removed by the steam generators and discharging to the condenser. Unit 1 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 automatic start of the auxiliary feedwater system is being reported as an eight-hour, non-emergency notification per 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. |
| ENS 56172 | 20 October 2022 20:24:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: At 1446 EDT on October 20, 2022, an individual was transported offsite for treatment at an offsite medical facility. Due to the nature of the medical condition, the individual was not thoroughly surveyed prior to being transported offsite. Follow-up surveys performed by radiation protection technicians identified no contamination of the worker or of the ambulance and response personnel. This is an eight-hour notification, non-emergency for the transportation of a contaminated person offsite. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xii). The NRC Resident Inspector has been notified. |
| ENS 56165 | 15 October 2022 15:46:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On 10/15/2022 at 1159 (EDT), during the Catawba Nuclear Station Unit 2 refueling outage, it was determined that the results of a planned surface examination Liquid Penetrant test (PT) performed on a previous overlay repair on nozzle number 74 of the reactor vessel closure head (RVCH) did not meet applicable acceptance standards. The examination was being performed to meet the requirements of Relief Request RA-21-0144, 'Proposed Alternative to Use Reactor Vessel Head Penetration Embedded Flaw Repair for Life of Plant'. The penetration required repairs for the discovered indications. The repairs have been completed in accordance with the ASME Code of Record prior to returning the vessel head to service. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The original indication that led to the overlay repair was discovered in April 2021, during ultrasonic testing and reported to the NRC and assigned EN55201. |
| ENS 56138 | 4 October 2022 10:27:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via email: This 60-day optional telephone notification is being made in lieu of an LER 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 invalid actuations of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 0628 Eastern Daylight Time (EDT) on August 6, 2022, an invalid actuation of group 6 Primary Containment Isolation Valves (PCIVs) (i.e., containment atmospheric control/monitoring and post accident sampling isolation valves) occurred. The group 6 isolation signal resulted from the reactor building ventilation radiation monitor `A' channel exceeding the setpoint value. This condition recurred at approximately 1305 EDT on August 12, 2022. In both instances, the `B' channel, located in the same plenum, remained steady and below the setpoint value through the entire event. This, along with readings made by radiation protection technicians, confirmed that there were no actual high radiation conditions in the reactor building exhaust in either instance. Following each invalid actuation, upon returning unit 2 reactor building ventilation to service, the `A' channel readings returned to be consistent with the `B' channel. It was determined that these invalid actuations likely resulted from degradation of circuit components associated with the radiation monitor. The `A' channel radiation monitor was replaced on September 22, 2022. During these two events, the PCIVs functioned successfully and the actuations were complete. The actuations were not initiated in response to actual plant conditions, they were not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the system. Therefore, these events have been determined to be invalid actuations. These events did not result in any adverse impact to the health and safety of the public. |
| ENS 56075 | 28 August 2022 07:08:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: (On 8/28/2022) at 0329 Eastern Daylight Time (EDT), with Unit 1 in Mode 1 at 100% power, the reactor was manually tripped due to a 'B' train main feedwater pump trip. The trip was not complex with all systems responding normally post-trip. The auxiliary feedwater (AFW) system started automatically as expected. Operations responded and stabilized the plant. Steam generator levels are being maintained by AFW through the AFW flow control valves. Decay heat is being removed by using the steam generator power-operated relief valves. The reason for the 'B' train main feedwater pump trip is under investigation. 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). 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 auxiliary feedwater 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: The cause of the 'B' train main feedwater pump trip is suspected to be the result of an electrical transient due to the alarms that the operators received. In addition, the 'A' train main feedwater pump also tripped subsequent to the reactor trip and that cause is still under investigation. |
| ENS 56016 | 25 July 2022 13:30:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via email: At 1058 Eastern Daylight Time (EDT) on July 25, 2022, it was determined that a non-licensed supervisor failed a test specified by the FFD testing program for the substance alcohol. The individual's authorization for site access has been terminated. The NRC Resident Inspector has been notified. |
| ENS 55997 | 15 July 2022 23:41:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via email: At 2020 Eastern Daylight Time (EDT) on July 15, 2022, the HPCI System was declared inoperable. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The Reactor Core Isolation Cooling (RCIC) System and Automatic Depressurization System (ADS) were operable during this time. HPCI availability was restored at 2023. Additional investigation is in-progress. There was no impact on the health and safety of the public or plant personnel. Unit 2 is not affected by this event. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: HPCI is considered inoperable but available at this time, resulting in a 14-day Shutdown LCO (Limiting Condition for Operation), due to the HPCI inoperability. |
| ENS 55955 | 22 June 2022 02:26:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: At 2240 on 06/21/2022, it was discovered that both required trains of Control Room Ventilation and Control Area Chilled Water System were simultaneously inoperable; therefore, this condition is being reported as an eight-hour, nonemergency notification per 10 CFR 50.72(b)(3)(v)(d). 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 'B' train was restored at 2315. |
| ENS 55888 | 7 May 2022 04:37:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via fax: At 2310 EDT on May 6, 2022, with Unit 3 in Mode 3, an actuation of the Emergency Feedwater (EFW) System occurred while entering a planned refueling outage. The reason for the EFW auto-start was a loss of all Main Feedwater (MFDW) Pumps which occurred when the 3A MFDW Pump tripped on steam generator (SG) overfill protection due to high level in the 3B SG. The high level in the 3B SG occurred when a Startup Feedwater Control Valve (3FDW-44) malfunctioned, resulting in excessive feedwater flow to the 3B SG. Investigation and repairs are in progress. Units 1 and 2 were not affected. This event is being reported as an 8-hr non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as a valid actuation of the EFW system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 55868 | 29 April 2022 07:49:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: At 0405 Eastern Daylight Time (EDT), with Unit 1 in Mode 1 at 100 percent power, the reactor was manually tripped due to degrading condenser vacuum. The trip was not complex, with all systems responding normally post-trip. The Auxiliary Feedwater System started automatically as expected. Operations responded and stabilized the plant. Decay heat is being removed by the Main Steam System to the main condenser using the turbine bypass valves. 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). 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 Auxiliary Feedwater 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 Tech Spec limits were exceeded. Offsite power is available. The suspected cause for the loss of condenser vacuum is when performing the scheduled monthly swap of condenser vacuum pumps, a suction valve failed to shut. |
| ENS 55859 | 26 April 2022 13:13:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee via fax or email: This 60-day telephone notification is being made in lieu of an LER submittal per 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 invalid actuations of systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 0040 Eastern Standard Time (EST) on March 7, 2022, Unit 1 received inadvertent High-Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) initiation signals. Subsequently, at approximately 0148 EST on March 7, 2022, Unit 1 received inadvertent Low-Pressure Coolant Injection (LPCI) and Core Spray initiation signals. In addition, all four Emergency Diesel Generators auto started, Group 10 (Instrument Air) Primary Containment Isolation System actuations occurred, and the Residual Heat Removal (RHR) Service Water Booster pumps tripped resulting in a brief interruption (approximately 9 minutes) to the Shutdown Cooling (SDC) heatsink. Jumpers, installed per planned refueling outage activities, prevented discharge of Emergency Core Cooling Systems into the reactor. HPCI, RCIC, and RHR Loop `A' were removed from service and under clearance. RHR SDC remained operable via RHR Loop `B' and forced circulation was maintained in the reactor. At the time of these events, Unit 1 was shutdown for refueling and the `A' and `C' reactor water level transmitters had been isolated in preparation for planned replacement. Leak-by of the instrument isolation valves occurred on both transmitters. Leak-by on the `C' instrument occurred at a faster rate with the `A' instrument providing the confirmatory signals resulting in Low Level 2 (LL2) and Low Level 3 (LL3) indication at approximately 0040 EST and 0148 EST, respectively. All actuations occurred as designed for LL2 and LL3 signals. During these events, reactor water level remained stable at the Reactor Vessel Head Flange and the `B' and `D' reactor water level transmitters remained off-scale-high, as expected under these conditions. Therefore, the actuations were 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 system (i.e., there was no low reactor water level condition). Considering the above, these actuations were invalid. There was no impact on the health and safety of the public or plant personnel. |
| ENS 55856 | 23 April 2022 06:04:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via fax or email: On April 23, 2022, at 0224 (EDT) hours, with Unit 2 in Mode 1 at 100 percent power, two control rods dropped during control rod testing resulting in misalignment, which required a manual reactor trip in accordance with plant procedure. All safety systems functioned as expected. The Auxiliary Feedwater system actuated as designed to provide makeup flow to the steam generators. Operations responded and stabilized the plant. Decay heat is being removed by the steam generator power operated relief valves. 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 automatic start of the Auxiliary Feedwater system is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). The cause of the dropped rods is being investigated. 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: Electrical power is in normal off-site arrangement. All emergency electrical supplies are available. |
| ENS 55800 | 23 March 2022 16:43:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via email and phone: At 1625 (EST) on 2/13/2022, with Unit 2 in Mode 3 at 0 percent power and plant heat up to normal operating temperature in progress, an actuation of the Emergency Feedwater System (EFW) occurred. The reason for the EFW auto-start was lowering water level in the 2A and 2B Steam Generators due to failure of the 2A Main Feedwater Pump to respond as required to maintain Steam Generator water level as Steam Generator pressure increased during plant heat up. The 2A and 2B Motor Driven Emergency Feedwater (MDEFW) pumps automatically started as designed when the 'low steam generator level' signal was received for the 2A and 2B Steam Generators. Following further evaluation, it was determined that a valid EFW actuation occurred, therefore this event is being reported as a late 8-hour non-emergency notification of a valid actuation of the EFW system in accordance with 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. |
| ENS 55780 | 9 March 2022 23:20:00 | Brunswick | NRC Region 2 | GE-4 | The following information was provided by the licensee: At 2013 EST on March 9, 2022, the HPCI System was declared inoperable following evaluation of routine HPCI surveillance testing data indicating that the required response time for reaching rated conditions was not met. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The Reactor Core Isolation Cooling (RCIC) System and Automatic Depressurization System (ADS) are operable. There was no impact on the health and safety of the public or plant personnel. Investigation is in-progress to determine the cause. Unit 1 is not affected by this event. Unit 1 is in a refueling outage. The NRC Resident Inspector has been notified.
The following information was provided by the licensee via email: At 20:13 EST on March 9, 2022, the HPCI System was declared inoperable following evaluation of routine HPCI surveillance testing data indicating that the required response time for reaching rated flow and pressure was not met. Subsequent to this, it was determined that the required response time was overly conservative for assuring the safety function of the system could be fulfilled. The required response time was revised. The operability determination for this event has been updated indicating that system operability was never lost for this event. There was not a condition that could have prevented the system from fulfilling the safety function. The NRC Resident Inspector has been notified. Notified R2DO (Miller). |
| ENS 55758 | 25 February 2022 16:10:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee: On 2/25/22, at 1133 EDT, the Technical Support Center (TSC) high temperature alarm annunciated in the Control Room due to an equipment malfunction that resulted in an unplanned loss of the TSC for greater than seventy-five minutes. If an emergency had been declared requiring TSC activation during this period, the TSC would have been staffed and activated using existing emergency planning procedures. If relocation of the TSC had been necessary, the Emergency Coordinator would have relocated the TSC staff to an alternate location in accordance with applicable site procedures. This is an eight-hour, non-emergency notification for a loss of Emergency Assessment Capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the equipment malfunction affected the functionality of an emergency response facility. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 55756 | 24 February 2022 14:35:00 | Brunswick | NRC Region 2 | GE-4 | 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 1316 Eastern Standard Time (EST) on January 4, 2022, during performance of isolation logic periodic testing associated with Primary Containment Isolation System Groups 2 and 6, an invalid actuation of Group 6 Primary Containment Isolation Valves (PCIVs) (i.e., Containment Atmospheric Control/Monitoring (CAC/CAM) and Post Accident Sampling (PASS) isolation valves) occurred. This resulted in a Division I CAC isolation signal, a full CAM isolation, and a full PASS isolation. Reactor Building Ventilation isolated and Standby Gas Treatment started per design. No manipulations associated with the isolation or reset logic were ongoing at the time. Troubleshooting determined that the Group 6 isolation signal resulted from a high resistance contact on a relay associated with the main stack radiation high-high isolation logic. This condition interrupted electrical continuity and prevented the Group 6 logic from resetting. Following cleaning of the relay contacts, the isolation logic remained in the reset state. The main stack radiation monitor is a shared component that sends isolation signals to Unit 1 and Unit 2. It was verified that the radiation monitor was not in trip electrically and there were no Unit 2 actuations. Therefore, 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 system. As a result, this event has been determined to be an invalid actuation. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector was notified. |
| ENS 55750 | 22 February 2022 01:44:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was provided by the licensee via fax or email: At 2207 (EST) on 2/21/2022 with Unit 2 in Mode 1 at 68 percent power, the reactor was manually tripped due to lowering water level in the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were 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). 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 phone and email: On 2/21/2022, Unit 2 was in Mode 1 increasing reactor power following startup from a forced outage. At 2205 (EST) with Unit 2 at 68 percent power, a feedwater control valve failed to properly control feedwater flow to the 2A Steam Generator and the Integrated Control System initiated an automatic runback. At 2207 (EST), the reactor was manually tripped from 39 percent power due to lowering water level in the 2A Steam Generator. Immediately following the manual reactor trip, an actuation of the Emergency Feedwater System (EFW) occurred. The 2A and 2B Motor Driven Emergency Feedwater (MDEFW) pumps automatically started as designed when the 'low steam generator level' signal was received for the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat was removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were not affected. Unit 2 was restarted on 2/27/2022 following repairs. Due to the Reactor Protection System actuation while critical, this event was reported on 2/22/2022 as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Following further evaluation, it was determined that a valid EFW actuation occurred, therefore this event is now also being reported as a late 8-hour non-emergency notification of a valid actuation of the EFW system in accordance with 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. Notified the R2DO (Miller). |
| ENS 55748 | 18 February 2022 08:35:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via telephone and email: On 2/18/2022, McGuire Nuclear Station Unit 2 experienced a turbine runback to 55 percent power. Based on concerns with unit stability, the reactor was manually tripped at 0459 (EST). All Auxiliary Feedwater pumps started on low steam generator level as required. The reactor trip was uncomplicated with all systems responding normally post trip. A feedwater isolation occurred as designed. Unit 1 was not affected. Due to the Reactor Protection System actuation while critical, actuation of the Turbine Driven Auxiliary Feedwater Pump and Motor Driven Auxiliary Feedwater pumps along with the Feedwater Isolation, this event is being reported as a four hour, nonemergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour nonemergency notification per 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: All control rods fully inserted. Decay heat is being removed via the condenser and normal feedwater. Unit 2 is in a normal shutdown electrical lineup. |
| ENS 55733 | 5 February 2022 04:32:00 | Oconee | NRC Region 2 | B&W-L-LP | The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At 0357 EST on 2/5/22, Oconee Unit 2 declared an Unusual Event due to a multiple fire alarms and visual observance of a smoke filled room in the West Penetration Room (EAL HU 4.1). Unit 2 automatically tripped and entered Mode 3. There was an indication that a release to the environment potentially occurred. Units 1 and 3 remained at 100% power. The Licensee notified the NRC Resident Inspector, the State, and local authorities. Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), and DHS Nuclear SSA (email).
The following information was provided by the licensee via email: At 0343 EST on February 5th, 2022, with Unit 2 in Mode 1 at 100% power, the reactor automatically tripped due to Reactor Coolant Pump (RCP) Flux/Flow Imbalance caused by the simultaneous trip of all 4 RCPs. The cause of the loss of all RCPs is under investigation. The trip was not complex. There was no inoperable equipment prior to the event that contributed to it. Operations responded and stabilized the plant. Decay heat is being removed by the Reactor Coolant System (RCS) in natural circulation with normal feedwater flow. Due to the Reactor Protection System (RPS) actuation while critical, this event is being reported as a four hour, nonemergency 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. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The Licensee notified the State and local authorities. Notified R2DO (Miller)
The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At 0811 EST on 2/5/22, Oconee Unit 2 terminated the notification of unusual event because EAL HU 4.1 criteria were no longer met. Unit 2 remains shutdown in Mode 3. The licensee has notified the State and local authorities and will notify the NRC Resident Inspector. Notified R2DO (Miller), IRD MOC (Gott), NRR EO (Regan), DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).
The following information was provided by the licensee via email: The follow-up investigation determine that the cause of the trip was determined to be a failed fuse in an undervoltage monitoring circuit for the electrical bus powering the reactor coolant pumps. The trip of the reactor coolant pumps resulted in an automatic reactor trip as designed. The plant responded as expected. There was no fire. The response of the main feedwater system caused an expected increase in temperature in a standby portion of the system which caused the breakdown of the pipe coating producing smoke. There was no release to the environment. The reading of a single instrument was determined to be invalid and other indications supported the conclusion that no release occurred. The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The Licensee notified the NRC Resident Inspector, State and local authorities. A media release was issued on 2/5/22. Notified R2DO (Miller), IRD MOC (Gott), NRR EO (Regan). |
| ENS 55713 | 26 January 2022 18:49:00 | Oconee | NRC Region 2 | B&W-L-LP | Licensee provided the following information via email: At 1050 EST on January 26, 2022, it was discovered that the required offsite and the overhead and underground paths of onsite emergency AC power were simultaneously inoperable; therefore this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(A). The overhead path and both required offsite paths were inoperable due to a lockout of the Unit 3 Startup Transformer CT-3. The underground path was made momentarily inoperable as part of aligning an additional offsite power source to Unit 3 to provide defense in depth to a loss of power. The safety function was restored at 1051 EST when the underground path was declared OPERABLE. The offsite power source was restored at 1651 EST. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
The Licensee updated the 3rd paragraph above as follows via email: The safety function was restored at 1051 EST when the underground path was declared OPERABLE. An offsite power source was restored through Transformer CT-5 within 15 minutes. Startup transformer CT-3 was restored and all offsite and the onsite overhead power source were returned to service by 1651 EST. Investigation of the cause of the CT-3 lockout is in progress. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified of this update. |
| ENS 55674 | 27 December 2021 16:49:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via email: On December 27, 2021, at 1014 EST, a system error in the site's Alert and Notification Siren System was identified, indicating a loss of the siren system affecting a greater than 25% of the emergency planning zone population. Review of the system's data logger indicates the system error has been present within the system since December 22, 2021, at 1245 EST. The fleet's telecommunications department has been contacted and is aware of the issue. In the event that a radiological emergency should occur at the Shearon Harris Nuclear Power Plant, Primary Route Alerting procedures will be put in use by the local jurisdictions. This condition is reportable as a Loss of Emergency Preparedness Capabilities per 10 CFR 50.72(b)(3)(xiii). The NRC Resident, state and local agencies have been notified.
The following information was provided by the Licensee via email: Further troubleshooting efforts identified that the Chatham County EOC Siren Activation Point remained capable of sending an alert signal to the sirens for the duration of the event described above. This ensures siren activation would be performed in a timely manner in the event of a radiological emergency. This Event Notification is therefore retracted, as no loss of emergency preparedness capabilities has occurred. The NRC Resident and local agencies have been notified. Notified R2DO (Miller) |
| ENS 55649 | 15 December 2021 16:45:00 | Harris | NRC Region 2 | Westinghouse PWR 3-Loop |
At 0927 EST on December 15, 2021, it was determined that a non-licensed employee supervisor failed a test specified by the fitness for duty (FFD) testing program. The individual's authorization for site access has been terminated. The NRC Resident Inspector has been notified. |
| ENS 55638 | 10 December 2021 03:54:00 | Oconee | NRC Region 2 | B&W-L-LP | At 0049 EST, on December 10, 2021, with Unit 2 in Mode 1 at 73 percent power, the reactor automatically tripped due to an unknown condition. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being maintained by discharge steam to the main condenser using the turbine bypass valves. Units 1 and 3 are not affected. The cause of the trip is under investigation. 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 to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. All rods inserted into the core during the trip. The plant is in its normal shutdown electrical lineup maintaining normal operating pressure and temperature. |
| ENS 55627 | 6 December 2021 18:14:00 | Brunswick | NRC Region 2 | GE-4 | On December 6, 2021, at 1125 hours Eastern Standard Time (EST), during planned maintenance activities, electrical power was lost to the 4160V emergency bus E-3. The power loss to emergency bus E-3 affected both Unit 1 and 2. Emergency Diesel Generator #3 received an automatic start signal but was under clearance for planned maintenance. Emergency bus E-3 was re-energized at 1315 EST hours via offsite power. The loss of power to E3 resulted in Unit 2 Primary Containment Isolation System (PCIS) Group 2 (i.e., Drywell Equipment and Floor Drain, Residual Heat Removal (RHR) Discharge to Radwaste, and RHR Process Sample), Group 3 (i.e., Reactor Water Cleanup), Group 6 (i.e., Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling Systems), and Group 10 (i.e., air isolation to the drywell) isolations. The actuations of PCIVs were completed and the affected equipment responded as designed. Per design, no Unit 1 safety system group isolations or actuations occurred. Other Unit 2 actuations included the Reactor Building Ventilation System isolation (i.e., Secondary Containment isolation), and the automatic start signal to the Standby Gas Treatment (SGT) System trains A and B and the Control Room Emergency Ventilation System (CREV). Systems functioned as designed. Safety systems functioned as designed following the de-energization of bus E-3. 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 PCIS on Unit 2 and an automatic start signal to Emergency Diesel Generator #3. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Except for the Emergency Diesel Generator, which is out of service for planned maintenance, all equipment has been returned to its normal alignment.
The loss of power to E3 resulted in Unit 1 Primary Containment Isolation System (PCIS) Group 6 (i.e., Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling Systems). Other Unit 1 actuations included the Reactor Building Ventilation System isolation (i.e., Secondary Containment isolation), and the automatic start signal to the Standby Gas Treatment (SGT) System trains A and B and the Control Room Emergency Ventilation System (CREV). Systems functioned as designed. Safety systems functioned as designed following the de-energization of bus E-3. 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 PCIS on Unit 1. All Unit 1 equipment was returned to its normal alignment. The NRC Resident will be notified. Notified R2DO (Miller). |
| ENS 55612 | 27 November 2021 13:16:00 | Oconee | NRC Region 2 | B&W-L-LP | At 0519 EST on November 27, 2021, with Unit 2 in Mode 5 at zero percent power, an actuation of the Emergency AC Electrical Power System occurred. The reason for the Emergency AC Electrical Power System auto-start was a lockout of the CT-2 transformer; causing a temporary loss of AC power to the main feeder bus. The Keowee Hydroelectric Units 1 and 2 automatically started as designed when a main feeder bus undervoltage 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 Electrical Power System. Additionally, the temporary loss of AC power resulted in a loss of Decay Heat Removal (DHR) that was restored upon power restoration to the main feeder bus. Therefore, this condition is also being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v) for an event or condition that could have prevented fulfillment of a safety function. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The loss of the CT-2 transformer is under investigation. Main feeder bus power was restored within a minute so no plant heat up occurred as a result of the loss of the decay heat removal system. |
| ENS 55549 | 27 October 2021 20:39:00 | Catawba | NRC Region 2 | Westinghouse PWR 4-Loop | At 1429 EDT on October 27, 2021 with Unit 1 in Mode 6 at 0 percent power, the 1B Emergency Diesel Generator (EDG) Load Sequencer was actuated by a valid undervoltage condition on the 1B 4160V Essential Bus that occurred during 1B Sequencer calibration activities. Valid signals were sent to both the 1B EDG and Unit 1 Auxiliary Feedwater (CA) systems. Neither system automatically started as they were both removed from service for maintenance activities at the time. 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 1B EDG and Unit 1 CA systems. There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |