Semantic search
| Entered date | Site | Region | Reactor type | System | Scram | Event description | |
|---|---|---|---|---|---|---|---|
| ENS 56938 | 29 January 2024 16:56:00 | Grand Gulf | NRC Region 4 | GE-6 | High Pressure Core Spray | The following information was provided by the licensee via email: At 1005 CST on January 29, 2024, Grand Gulf Nuclear Station was conducting surveillance testing on the high pressure core spray system. During testing, the 1E22F012 minimum flow valve failed to return to the full closed position. The valve went from full open indication to dual indication. The event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition which could have prevented the fulfillment of a safety function. Troubleshooting is in progress. The NRC Senior Resident has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: All off-site power is available. No other systems are out of service and there are no compensatory measures taken. There is no increase to plant risk. | |
| ENS 56936 | 29 January 2024 13:32:00 | Peach Bottom | NRC Region 1 | GE-4 | High Pressure Coolant Injection Primary Containment Isolation System Reactor Core Isolation Cooling Residual Heat Removal Main Condenser Control Rod | 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 56935 | 27 January 2024 23:39:00 | Watts Bar | NRC Region 2 | Westinghouse PWR 4-Loop | Reactor Protection System Auxiliary Feedwater Control Rod | The following information was provided by the licensee via email: At 2141 EDT, with Unit 2 in Mode 1 at 100 percent power, the reactor automatically tripped due to a main turbine trip. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being removed using the auxiliary feedwater and steam dump systems. 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 expected actuation of the auxiliary feedwater system (an engineered safety feature) is being reported as an eight hour report under 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. All control rods are fully inserted. The cause of the turbine trip is being investigated. The licensee notified the NRC Resident Inspector. | |
| ENS 56928 | 18 January 2024 21:38:00 | Columbia | NRC Region 4 | GE-5 | Service water Residual Heat Removal Spray Pond | The following information was provided by the licensee via email: On January 18, 2024, at 0030 PST, diesel generator 2 (DG2) was shut down following a monthly surveillance run. Subsequently, a leak was discovered in the DG2 building. Service water pump '1B' was secured at 0117, effectively stopping the leak. The leak was determined to be service water coming from a diesel generator mixed air cooling coil. Service water system 'B' and DG2 were subsequently declared inoperable at 0135. After discussion with engineering, it was identified that the amount of service water leakage from the cooling coil was assumed to be greater than the leakage allowed by the calculation to assure adequate water in the ultimate heat sink to meet the required mission time of 30 days. At 1204, it was determined that entry into Technical Specification 3.7.1 condition D was warranted since the assumed leakage from the cooling coil could exceed the calculated allowed value. At 1238, the control power fuses for service water pump '1B' were removed. DG2 and service water system 'B' were declared unavailable, and the technical specification condition for the inoperable ultimate heat sink was exited. With the control power fuses removed, the pump is kept from auto starting, effectively preventing the leak and ensuring the safety function of the ultimate heat sink is maintained while the cooling coil is repaired or replaced. Due to the leakage assumed greater than the calculated allowable value this condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition and per 10 CFR 50.72(b)(3)(v)(B) as an event or condition that could have prevented fulfillment of the safety function of structures or systems that are needed to remove residual heat. There was no impact to the health and safety of the public. The NRC Resident has been notified.
The following information was provided by the licensee via email: On January 18, 2024 at 2138 EST, Columbia Generating Station notified the NRC under 10 CFR 50.72(b)(3)(ii)(B) of an unanalyzed condition on the available capacity of the ultimate heat sink (UHS) and under 10 CFR 50.72(b)(3)(v)(B) of an event or condition that could have prevented fulfillment of the safety function of structures or systems needed to remove residual heat. On January 18, 2024, following monthly surveillance of the diesel generator DG2, a DG2 room cooler flow alarm was received at 0115. A leak was discovered in the diesel mixed air (DMA) air handler unit. Service Water Pump '1B' was secured and the leakage was stopped at 0117. The service water system 'B' and diesel generator system 'B' were declared inoperable at 0135. The leak was assumed to be greater than that allowed to ensure adequate water in the UHS required to meet the 30-day mission time, and the UHS was declared inoperable at 1204. Control power fuses for the service water pump '1B' were removed to fully eliminate the leakage path from the cooler, and the UHS was declared operable at 1238. Following the event, engineering performed an analysis based on the size and location of the leak, and concluded it would have taken 1.4 days to deplete the available excess water in the UHS to below the minimum technical specification required water level of the spray pond. Operations were able to secure the service water subsystem of the UHS prior to exceeding the volumetric margins in the spray ponds to ensure the 30-day mission time was met. The condition did not represent a safety significant unanalyzed condition nor a loss of safety function. The NRC Resident Inspector has been notified. Notified R4DO (Gepford). | |
| ENS 56915 | 5 January 2024 18:18:00 | Davis Besse | NRC Region 3 | B&W-R-LP | Shield Building | The following information was provided by the licensee via phone and email: At approximately 1111 EST on 01/05/2024, a mechanical penetration room door was discovered unlatched. Based on security badge history, the door was last opened at 1040 EST. The unlatched door resulted in both trains of the station emergency ventilation system being inoperable due to being unable to maintain the shield building negative pressure area. With both trains simultaneously inoperable, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The door was closed and verified latched upon discovery to restore the systems to an operable status. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
The station emergency ventilation system (EVS) was tested with the mechanical penetration room door unlatched. The test results showed that the station EVS attained the required negative pressure in the shield building within the time required by the Technical Specifications. Therefore, the station EVS remained operable with the door unlatched, and this issue did not prevent the system from fulfilling its safety function to control the release of radioactive material and mitigate the consequences of an accident. The NRC Resident Inspector has been notified. Notified R3DO (Orlikowski) | |
| ENS 56914 | 5 January 2024 15:56:00 | Perry | NRC Region 3 | GE-6 | The following information was provided by the licensee via phone and email: At 1552 (EST) on 01/05/2024, Perry Nuclear Power Plant reported elevated levels of tritium in the underdrain system to the state of Ohio as a non-voluntary reporting of tritium. An investigation is currently ongoing to identify the cause of the elevated tritium levels. The tritium levels in this location do 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 56912 | 3 January 2024 15:38:00 | Saint Lucie | NRC Region 2 | CE | Reactor Coolant System | At 1257 EST on January 3, 2024, it was determined that a class 1 system barrier had a through wall flaw with leakage. The leakage renders both trains of high pressure safety injection inoperable. The unit is being cooled down to cold shutdown to comply with technical specifications. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officer Report Guidance: At the time of the discovery, the unit was shutdown in mode 3. The unit was experiencing signs of reactor coolant system leakage and a shutdown was initiated in order to search for possible sources. The unit is currently cooling down and proceeding to mode 5, where the safety function is not required.
The purpose of this notification update is to retract a portion of a previous report, made on 1/03/2024 at 1257 EST (EN 56912). Notification of the event to the NRC was initially made as a result of declaring both trains of unit 2 high pressure safety injection system inoperable due to reactor coolant barrier through wall leak on the vent line for the 2A2 safety injection tank. Subsequent to the initial report, Florida Power and Light has concluded that the through wall leak rate was insignificant, and therefore the safety injection system's safety-related function was maintained. Therefore, this portion of the event is not considered a safety system functional failure and is not reportable to the NRC pursuant 10 CFR 50.72(3)(v)(D). This update does not affect the original 10 CFR 50.72(b)(3)(ii)(A) report for the degraded condition related to the reactor coolant barrier through wall leak. The NRC Resident Inspector has been notified. Notified R2DO (Miller). | |
| ENS 56910 | 28 December 2023 18:55:00 | Watts Bar | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: Plant alignment caused an unanalyzed condition regarding unit 1 and unit 2 Appendix R procedures. (Watts Bar Nuclear) (WBN) unit 1 and unit 2 Appendix R procedures require manual operator action times including (volume control tank) (VCT) isolation. They are calculated with an assumed hydrogen cover gas constant at 20 psig. This is to preclude hydrogen ingestion into the charging pumps with an operator action time of 70 minutes. Due to recent lower hydrogen concentration in the (reactor coolant system) (RCS), (unit 2) VCT hydrogen regulator set point was increased to 28 psig. This increased pressure set point invalidated the initial assumptions made in the Appendix R calculations for manual operator action times. WBN unit 1 VCT hydrogen regulator was also verified high out of band at 22 psig. WBN has restored unit 1 and unit 2 VCT hydrogen regulators to the required specification. The NRC Resident Inspector has been notified of this condition. | ||
| ENS 56897 | 18 December 2023 13:34:00 | Hatch | NRC Region 2 | GE-4 | Secondary containment Main Steam Isolation Valve Reactor Core Isolation Cooling Primary containment Reactor Water Cleanup | The following information was provided by the licensee via email and phone: At 2011 EDT on 11/01/23, with Unit 2 in Mode 3 at 0 percent power, Unit 2 received multiple spurious actuations. These actuations consisted of a partial group 1 and a partial group 5 primary containment isolation and a partial secondary containment isolation. The partial Group 1 isolation resulted in the closure of two main steam isolation valves (MSIVs); all other MSIVs were already closed. The partial group 5 isolation auto closed one of the reactor water cleanup (RWCU) isolation valves. The partial secondary containment isolation resulted in the closure of the inboard refueling floor and reactor building secondary containment isolation valves (SCIVs). Additionally, at 2238 EDT, Unit 2 again received multiple spurious actuations. These actuations consisted of a partial group 5 primary containment isolation and a partial secondary containment isolation. The partial group 5 isolation auto closed one of the RWCU isolation valves The partial secondary containment isolation resulted in the closure of the inboard refueling floor and reactor building SCIVs. And again, at 2354 EDT, Unit 2 received spurious actuations which consisted of a partial secondary containment isolation which resulted in the closure of the inboard refueling floor and reactor building SCIVs. The spurious actuations seen on 11/1/23 are triggered at -35 inches reactor water level (RWL) for group 5 and secondary containment isolations and at -101 inches RWL for group 1 isolations. It was determined that a combination of the RWL fluctuating above and below the wide range instrument reference leg tap, the reactor vessel pressure being lowered, and reactor core isolation cooling introducing colder water conditions near the reference leg tap of the wide range instrument caused the spurious actuations. Using multiple RWL indications for each of the instances mentioned above, the actuations were confirmed to be spurious as RWL was being controlled in a band of +55 inches to +85 inches at the time of the actuations. This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in an invalid actuation of a partial group 1, a partial group 5, and partial secondary containment logic. The NRC Resident has been notified. | |
| ENS 56896 | 18 December 2023 07:40:00 | Hatch | NRC Region 2 | GE-4 | High Pressure Coolant Injection Reactor Core Isolation Cooling Emergency Core Cooling System | The following information was provided by the licensee email: At 0223 EST, on 12/18/2023, while Unit 2 was at 100 percent power in mode 1, the high pressure coolant injection (HPCI) outboard steam isolation valve closed resulting in the HPCI system being declared inoperable. The cause of the outboard steam isolation valve closing is under investigation. HPCI does not have a redundant system, therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The safety function was restored at 0512, on 12/18/23, and HPCI has been declared operable. Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) were operable during this time. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56894 | 16 December 2023 08:22:00 | Grand Gulf | NRC Region 4 | GE-6 | Feedwater Reactor Protection System Control Rod | Automatic Scram | The following information was provided by the licensee via email: On December 16, 2023, at 0350 CST, Grand Gulf Nuclear Station was operating in mode 1 at 81 percent power when an automatic scram occurred due to a turbine trip signal. Before the scram the unit was performing a rod sequence exchange, and no critical work was underway. The cause of the turbine trip signal is not known at this time and is being investigated. All control rods fully inserted, there were no complications, and all plant systems responded as designed. Reactor water level is being maintained by main feedwater and condensate. Reactor pressure is being maintained with main turbine bypass valves. No radiological releases have occurred due to this event. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of the reactor protection system when the reactor is critical and specified system actuation due to expected reactor water level 3 isolation signals on a reactor scram. The NRC Senior Resident Inspector has been notified of this event. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Group 2 and Group 3 isolations occurred on the Level 3 isolation signal. |
| ENS 56893 | 16 December 2023 04:04:00 | Saint Lucie | NRC Region 2 | CE | Reactor Coolant System | At 2045 EST on December 15, 2023, it was determined that the reactor coolant system barrier had a through wall flaw with leakage. The leakage is minor in nature and unquantifiable. The leakage is coming from the welded connection of a vent valve for safety injection tank 2A2 outlet valve rendering both trains of high-pressure safety injection inoperable. The unit is being cooled down to cold shutdown to comply with technical specifications. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A) and 10 CFR 50.72(b)(3)(v)(D). 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 unit was heating up after a maintenance outage. The leak was discovered during mode 3 walkdown.
The purpose of this notification update is to retract a portion of a previous report, made on 12/16/2023 at 0404 EST (EN 56893). Notification of the event to the NRC was initially made as a result of declaring both trains of unit 2 high pressure safety injection system inoperable due to reactor coolant barrier through wall leak on the vent line for the 2A2 safety injection tank. Subsequent to the initial report, Florida Power and Light has concluded that the through wall leak rate was insignificant, and therefore the safety injection system's safety-related function was maintained. Therefore, this portion of the event is not considered a safety system functional failure and is not reportable to the NRC pursuant 10 CFR 50.72(3)(v)(D). This update does not affect the original 10 CFR 50.72(b)(3)(ii)(A) report for the degraded condition related to the reactor coolant barrier through wall leak. The NRC Resident Inspector has been notified. Notified R2DO (Miller). | |
| ENS 56889 | 14 December 2023 21:05:00 | Hope Creek | NRC Region 1 | GE-4 | Feedwater Main Condenser Control Rod | The following information was provided by the licensee via phone call and email: On December 14, 2023, at 1939 EST, Hope Creek reactor scrammed following closure of turbine control valve number 4. All control rods fully inserted into the core. All safety systems responded as designed and expected. There was no radiological release. The unit is stable in mode 3 with decay heat being removed via the turbine bypass valves rejecting steam to the main condenser. Normal feedwater level control is providing makeup to the reactor vessel. No personnel injuries resulted from the event. The outage control center has been staffed to determine the cause of the reactor scram. The Hope Creek NRC Resident Inspector has been notified. | |
| ENS 56887 | 13 December 2023 05:50:00 | River Bend | NRC Region 4 | GE-6 | Feedwater Reactor Protection System Reactor Core Isolation Cooling | Automatic Scram | The following information was provided by the licensee via phone and email: At 0102 CST, while operating at 100 percent (reactor) power, River Bend Station experienced an automatic reactor scram caused by a turbine trip signal. The cause of the turbine trip signal is not known at this time and is being investigated. At 0108, reactor core isolation cooling (RCIC) was initiated due to a loss of reactor feed pumps following feedwater heater string isolation. At 0114, reactor water level control was transferred back to feedwater and RCIC was secured. Reactor water level is being maintained by feedwater pumps and reactor pressure is being maintained by turbine bypass valves. The scram was uncomplicated and all other plant systems responded as designed. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical and 10 CFR 50.72(b)(3)(iv)(A) specified system actuation as result of expected post scram (reactor water) level 3 isolations and manual initiation of RCIC. No radiological releases have occurred due to this event from the unit. The NRC Senior Resident Inspector has been notified of this event. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The cause of the turbine trip, while still under investigation, was likely due to an electrical transient involving the main generator. Walkdowns in the switchyard post-scram identified damage to one of the output breaker disconnects. |
| ENS 56877 | 2 December 2023 12:47:00 | South Texas | NRC Region 4 | Westinghouse PWR 4-Loop | Emergency Diesel Generator | The following information was provided by the licensee via email: At 0610 CST on 12/2/2023, with Unit 2 in Mode 1 at 100 percent power, the South Texas Project switchyard south electrical bus was de-energized. Emergency diesel generator (EDG) '22' automatically started in response to the loss of offsite power on the train 'B' engineered safety feature (ESF) electrical bus. This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in the valid actuation of an emergency AC electrical power system (50.72(b)(3)(iv)(B)(8)). All required loads were successfully started. 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 initial loss of the south electrical bus, partial loss of off-site power, put the plant in a 24 hour limiting condition for operation (LCO) in accordance with (IAW) technical specification (TS) 3.8.1.1.E. Power was restored to the train 'B' ESF bus via an alternate offsite power source and the EDG was returned to its automatic standby condition. Currently, the plant is in a 72 hour LCO IAW TS 3.8.1.1.A. | |
| ENS 56875 | 29 November 2023 17:02:00 | Indian Point | NRC Region 1 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: This notification is being made per 10 CFR 50.72(b)(2)(xi), as a result of notifications made to State and local government agencies for the discovery of an oil sheen in the discharge canal outside Unit 3. The New York State Department of Environmental Conservation and Westchester County Department of Health were notified. No sheen was observed in the river or at the southern end of the discharge canal near the outfall gates. Clean up efforts are underway. The licensee will notify the NRC Project Manager. | ||
| ENS 56866 | 20 November 2023 17:53:00 | Dresden | NRC Region 3 | GE-3 | High Pressure Coolant Injection Emergency Core Cooling System | 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 licensee's corrective action program. | |
| 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 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 56863 | 18 November 2023 02:51:00 | River Bend | NRC Region 4 | GE-6 | Feedwater Reactor Protection System Emergency Diesel Generator Control Rod | Manual Scram | The following information was provided by the licensee via phone and email: On November 17, 2023, at 2215 CST, River Bend Station (RBS) was operating at 30 percent reactor power performing plant startup activities when an isolation of low-pressure feedwater string `A' occurred. The team entered applicable alternate operating procedures and inserted control rods to exit the restricted region of the power to flow map. Feedwater temperature continued to lower until it challenged the prohibited region of the AOP-0007 graph requiring a reactor scram. The team inserted a manual reactor scram at 2355 from 24 percent reactor power. All control rods fully inserted and there were no complications. All systems responded as designed. Currently RBS Unit 1 is stable with reactor level being maintained 10 to 51 inches with feed and condensate, and pressure being maintained 500 to 1090 psig using steam drains. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical and 10 CFR 50.72(b)(3)(iv)(A) Specified System Actuation as result of Group 3 isolations. The NRC Senior Resident inspector has been notified. No radiological releases have occurred due to this event from the unit. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The electric plant is in a normal lineup for current plant conditions with all emergency diesel generators available. The cause of the initial isolation of low-pressure feedwater string "A" is still under investigation. |
| ENS 56861 | 16 November 2023 21:30:00 | South Texas | NRC Region 4 | Westinghouse PWR 4-Loop | Emergency Diesel Generator HVAC Control Room Envelope Containment Spray | The following information was provided by the licensee via phone and email: 11/05/23, 2200 CST: Essential Chiller 'B' train and associated cascading equipment were declared INOPERABLE for planned maintenance. Unit 2 entered the Configuration Risk Management Program as required by Technical Specifications on 11/12/23 at 2200. 11/16/23, 1541: Essential Chiller 'C' train and associated cascading equipment were declared INOPERABLE due to an unexpected material condition causing the Essential Chiller to trip. The most limiting (Limiting Condition of Operability) LCO is 3.7.7, Action c. This condition resulted in the INOPERABILITY of two of the three safety trains required for the accident mitigating function including: High Head Safety Injection, Low Head Safety Injection, Containment Spray, Electrical Auxiliary Building HVAC, Control Room Envelope HVAC, Essential Chilled Water. This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident. A risk analysis was performed for the equipment INOPERABILITY and mitigating actions have been taken per site procedures. All 'A' train equipment remains operable. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The 'B' train Emergency Diesel Generator was also inoperable due to planned maintenance and continues to be inoperable. It was considered in the Configuration Risk Management Program and it was determined this condition could be maintained. LCO 3.7.7, Action c requires reactor shutdown within 72 hours. | |
| 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 56856 | 16 November 2023 05:15:00 | Calvert Cliffs | NRC Region 1 | CE | Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater Main Condenser | Automatic Scram | 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 56852 | 14 November 2023 14:36:00 | Farley | NRC Region 2 | Westinghouse PWR 3-Loop | Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater | Manual Scram | The following information was provided by the licensee via phone and email: At 1041 CST on 11/14/23 with Farley Unit 2 in Mode 1 at 10 percent power, the reactor was manually tripped due to rising steam generator levels. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Auxiliary feedwater (AFW) was manually initiated in accordance with plant procedures and is feeding the steam generators. Heat removal is being provided via the atmospheric relief valves. 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). This event is also being reported as an eight-hour, non-emergency notification per 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. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: All rods fully inserted. The licensee attempted to take manual control of the feedwater control valves to lower steam generator level but, due to reaching a steam generator level that requires a manual trip, the licensee manually tripped the reactor. |
| ENS 56850 | 12 November 2023 22:02:00 | Watts Bar | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On November 12, 2023, at 0300 EST, a Watts Bar contractor was transported offsite for medical treatment due to a work-related injury. Upon arrival at an offsite medical facility, medical personnel determined the injury required the individual to be admitted into the hospital and will be kept overnight. The individual was inside of the Radiological Controlled Area, however was free released with no contamination. The injury and hospitalization were reported to the Occupational Safety and Health Administration (OSHA) under 29 CFR 1904.39(a)(2). The contracting agency informed OSHA at 1319 EST. Watt Bar Operations personnel were officially notified by the contracting agency of the report made to OSHA at 1945 EST. 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 56849 | 11 November 2023 00:23:00 | Waterford | NRC Region 4 | CE | The following information was provided by the licensee via email: At 1545 CST on November 10, 2023, personnel at Waterford Steam Electric Station Unit 3 determined that 19 conduits in the engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition meets the criteria involving an unanalyzed condition that significantly affects plant safety. The plant is currently defueled. Decay heat is being removed by normal spent fuel cooling system operations. ESFAS is not required to be operable in the current plant mode. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. There was no impact to the health and safety of the public or plant personnel. The NRC Region 4 Branch Chief (Dixon) has been notified.
On November 10, 2023, Waterford Steam Electric Station Unit 3 reported in EN 56849 that 19 conduits in engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition met the criteria involving an unanalyzed condition that significantly affects plant safety. Waterford 3 has determined that the ESFAS auxiliary relay cabinets A and B jumper conduits do not require fire seals based on review of an engineering specification that specifies the size and length of conduits which require fire seals to be installed. None of the nineteen affected conduits meet the size and length criteria that would necessitate installation of a fire seal. Based on this, the condition described in EN 56849 is not considered to be an unanalyzed condition that significantly affects plant safety as described in 10 CFR 50.72(b)(3)(ii)(B) and therefore is not reportable. The licensee notified the NRC Resident Inspector. Notified R4DO (Gaddy) | ||
| ENS 56848 | 10 November 2023 22:52:00 | South Texas | NRC Region 4 | Westinghouse PWR 4-Loop | HVAC Control Room Envelope Containment Spray | The following information was provided by the licensee via email: On 11/10/23 at 0642 CST, essential chiller 'B' train and cascading equipment was declared inoperable due to chill water temperature exceeding limits. At 1413 CST, essential chiller 'C' train and cascading equipment was declared inoperable due to discharge pressure exceeding limits. This condition resulted in an inoperable condition on two out of the three safety trains for the accident mitigating function including the 'B' and 'C' train high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chill water. All 'A' train equipment remained operable. This was determined to be reportable within 8 hours as required by 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Plant is in a 72 hour limiting condition for operation per technical specification 3.7.7. Restoration of 'B' train anticipated on 11/11/23 mid day. | |
| ENS 56846 | 10 November 2023 03:14:00 | Susquehanna | NRC Region 1 | GE-4 | Feedwater Reactor Protection System Main Condenser | Manual Scram | The following information was provided by the licensee via email: At 0118 EST, with Unit 1 in Mode 1 at 100 percent power, the reactor was manually scrammed due to degrading main condenser vacuum. The scram was not complex, with all systems responding normally post-scram. The main turbine bypass valves opened automatically to maintain reactor pressure. Operations responded and stabilized the plant. Reactor water level is being maintained via feedwater pumps. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 2 is not impacted. Due to Reactor Protection System actuation while critical, this event is being reported as a four-hour and eight-hour non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). Unit 1 reactor is currently stable in mode 3. An investigation is in progress into the cause of the degrading condenser vacuum. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56845 | 9 November 2023 15:55:00 | Sequoyah | NRC Region 2 | Westinghouse PWR 4-Loop | The following is a summary of information provided by the licensee via email: A controlled substance was found in the protected area. The NRC Resident Inspector has been notified. | ||
| ENS 56841 | 8 November 2023 13:27:00 | Calvert Cliffs | NRC Region 1 | CE | Steam Generator Feedwater Auxiliary Feedwater | 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 | Steam Generator Feedwater Reactor Protection System Auxiliary Feedwater Main Condenser | Automatic Scram | 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 56838 | 7 November 2023 18:18:00 | Seabrook | NRC Region 1 | Westinghouse PWR 4-Loop | Steam Generator Feedwater Auxiliary Feedwater | The following information was provided by the licensee via email: On November 07, 2023 at 1200 EST, it was discovered that all pumps in the Auxiliary Feedwater system were inoperable due to the loss of control power to the 'B' train Emergency Feedwater (EFW) flow control valve which supplies the 'D' steam generator. The redundant 'A' train EFW control valve for the 'D' steam generator remains functional, as well as the capability of the Auxiliary Feedwater system to supply all steam generators. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(B). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The 'A' and 'B' EFW Flow Control Valves are arranged in a series configuration for each Steam Generator. Failure of any of the 8 EFW Flow Control Valves to meet its Surveillance Requirements will render all EFW Pumps inoperable per tech specs. | |
| ENS 56834 | 5 November 2023 17:52:00 | Waterford | NRC Region 4 | CE | Steam Generator | The following information was provided by the licensee via email: At 1033 CST on November 5, 2023, while in a refueling outage, it was determined that Waterford Steam Electric Station, Unit 3, did not meet the performance criteria for steam generator structural integrity in accordance with Technical Specification 6.5.9.b.1, Steam Generator Program, due to two tube failures in the number 1 steam generator. The condition was identified during performance of in-situ pressure testing. The affected tubes will be plugged. The plant is currently stable with all fuel in the spent fuel pool. Decay heat is being removed by normal spent fuel cooling system operation. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A) as a degraded condition. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56832 | 4 November 2023 01:11:00 | Comanche Peak | NRC Region 4 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via email: On 11/03/2023 at 2231 CDT, a security officer found 2 bottles of vanilla extract in the protected area. One bottle was a 1.5 ounce size with a trace amount of vanilla in the bottle, the other bottle was a 4.5 ounce size with approximately 1 ounce of vanilla. Alcohol was identified as an ingredient on the label. It was determined the vanilla extract is 35 percent alcohol by volume (ABV), above the 0.5 percent ABV considered low alcohol content. Security personnel took custody of the bottles of vanilla extract. 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 56829 | 2 November 2023 16:41:00 | Point Beach | NRC Region 3 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On November 2, 2023, at 0715 CDT, it was discovered that the results of a blind performance specimen provided to a Health & Human Services (HHS)-certified testing facility were not as expected. The blind specimen results indicated a false negative for MDA/MDMA and a false positive for amphetamines. Investigation is ongoing to determine if the results are accurate. This report is being made in accordance with 10 CFR 26.719(c)(2) and 10 CFR 26.719(c)(3). The NRC Resident Inspector has been notified by the licensee."
Follow-up investigation by an independent Health and Human Services laboratory confirmed that the blind specimen in question was analyzed correctly. The error is thought to have occurred during the preparation of the blind specimen, prior to delivery to the site. The NRC Resident Inspector has been notified by the licensee. Notified R3DO (Orlikowski) and FFD Group (email). | ||
| ENS 56827 | 1 November 2023 16:52:00 | Prairie Island | NRC Region 3 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On October 31 at 1856 CDT, Prairie Island Nuclear Generating Plant personnel identified a prohibited item (alcohol) in a kitchen area located within the protected area. An 'Extent of Condition' search was performed of all other protected area kitchen areas, no additional prohibited items were found. The NRC Resident has been notified. | ||
| ENS 56826 | 1 November 2023 09:38:00 | Hatch | NRC Region 2 | GE-4 | High Pressure Coolant Injection Reactor Protection System Reactor Core Isolation Cooling Emergency Core Cooling System Main Condenser | Manual Scram | The following information was provided by the licensee via email: At 0648 EDT on 11/1/23, with Unit 2 in MODE 1 at 56 percent power, the reactor was manually tripped due to a trip of the 'B' reactor feed pump (RFP). The 'A' RFP had been previously isolated due to a leak. Closure of containment isolation valves (CIVs) in multiple systems and the actuation of high pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) occurred as a result of reaching the actuation setpoint on reactor water level as designed. The trip was not complex, with all safety systems responding normally post-trip. Operations responded and stabilized the plant. Reactor water level is being maintained with RCIC. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 was not affected. Due to the emergency core cooling system (ECCS) discharging into the reactor this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A). Also, the reactor protection system actuation while critical is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of CIVs, RCIC and HPCI. There was no impact on the health and safety of the public or plant personnel. The Resident Inspector was notified. |
| ENS 56825 | 31 October 2023 14:20:00 | River Bend | NRC Region 4 | GE-6 | The following information was provided by the licensee via phone call and email: On October 31, 2023, at 0800 CDT, River Bend Station discovered that the results of a blind performance sample provided to an Health and Human Services (HHS)-certified testing facility were inaccurate (false negative). This report is being made in accordance with 10 CFR 26.719(c)(3). The HHS-certified testing facility has been informed of the error. The licensee notified the NRC resident inspector.
On November 1, 2023, River Bend Station personnel were informed by the HHS-certified testing facility that the cut-off levels used for analysis of the performance testing sample in question were the correct (higher) cut-off levels currently being used by the licensee. This resulted in a correct negative test. The performance testing sample sent to the HHS-certified testing facility was purchased for use based on the new lower cut-off levels in accordance with the new fit for duty (FFD) rule being implemented by the licensee on November 6, 2023. Because the higher confirmatory cut-off levels were used at the HHS-certified testing facility, the results provided were correct. The NRC Resident Inspector has been notified." Notified R1DO (Eve) and FFD Group (email) | ||
| 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 56815 | 25 October 2023 15:09:00 | Pilgrim | NRC Region 1 | GE-3 | The following information was provided by the licensee via phone and email: This is a non-emergency 30-day notification for missing licensed material. This event is reportable in accordance with 10 CFR 20.2201(a)(1)(ii). On September 25, 2023, while performing the required semi-annual source leak check and inventory, radiation protection personnel could not locate seven sealed radioactive sources. Five of the sources exceed the reporting threshold of ten times the activity listed in 10 CFR 20 Appendix C. Of the five sources, four were Ni-63 sources previously utilized in security bomb detection equipment with a current source radioactivity of between 7.1 and 8.7 mCi. The fifth sealed source exceeding the reporting threshold is an Am-241 former lab calibration standard with a source radioactivity of 0.97 microcuries. These sources were last accounted for on July 6, 2022. Pilgrim's accountability process does not require leak checks or physical inventory of sources that are out of service. A search was conducted for the missing sources; however, they could not be located. These sealed sources are classified as Category 5 radioactive sources in accordance with the International Atomic Energy Agency (IAEA) Safety Guide No. RS-G-1.9. Sources that are less than Category 3 (Cat 4 and 5 sources) are very unlikely to cause permanent injury to individuals. Based on the activity of Ni-63 and Am-241 present in the sources, this 30-day phone notification to NRC is provided pursuant to 10CFR20.2201(a)(1)(ii). The required written report pursuant to 10CFR20.2201(b)(1) will be provided to NRC within 30 days. The Resident Inspector has been notified. The licensee will notify State and local authorities. THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf | ||
| ENS 56813 | 25 October 2023 01:12:00 | Turkey Point | NRC Region 2 | Westinghouse PWR 3-Loop | Reactor Protection System Auxiliary Feed Water | Automatic Scram | The following information was provided by the licensee via email: At 2159 on 10/24/2023, with Unit 3 in Mode 1 at 100 percent power, the reactor was automatically tripped due to an actuation signal into the Unit 3 reactor protection system protection rack during maintenance. The trip was uncomplicated with all systems responding normally post trip. Decay heat is being removed via auxiliary feed water system and the steam dump system. Unit 4 is not affected. This event is being reported pursuant to 10CFR50.72(b)(2)(iv)(B) and 10CFR50.72(b)(3)(iv)(A). The NRC Resident Inspector has been notified. The cause of the automatic reactor trip will be investigated by the licensee. |
| ENS 56811 | 22 October 2023 16:40:00 | Cooper | NRC Region 4 | GE-4 | Secondary containment Reactor Building Ventilation | The following information was provided by the licensee via fax and phone: On October 22, 2023, at 1149 CDT, with the reactor at 100 percent core thermal power and steady state conditions, the Cooper Nuclear Station secondary containment differential pressure exceeded the Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.1.1 limit of -0.25 inches water gauge. The condition existed for approximately 80 seconds until the reactor building ventilation system responded to restore differential pressure to normal. Investigations identified a hinged duct access hatch found open. The hatch was closed and latched, and ventilation system parameters were returned to normal. There were no radiological releases associated with this event. Declaring secondary containment inoperable as a result of not meeting TS SR 3.6.4.1.1 is reportable under 10 CFR 50.72(b)(3)(v)(C) and (D) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material and mitigate the consequences of an accident. The NRC Senior Resident Inspector has been informed. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At the time the licensee notified the NRC Headquarters Operations Officer, the cause of the hinged access duct being open had not been determined. This event has been added to the licensee's corrective action program. | |
| ENS 56810 | 22 October 2023 01:43:00 | Nine Mile Point | NRC Region 1 | GE-2 | Reactor Recirculation Pump | 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 56809 | 21 October 2023 09:25:00 | Watts Bar | NRC Region 2 | Westinghouse PWR 4-Loop | The following information was provided by the licensee via fax and email: Fire potentially degrading the level of safety of the plant. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At 0907 EST, the licensee declared a notification of unusual event, under emergency action level HU.4, due to multiple fire alarms and CO2 discharge in the emergency diesel building. When the plant fire brigade entered the building, there was no indication of fire or damage to any plant equipment. The cause of the multiple alarms is under investigation. State and local authorities were notified and no offsite assistance was requested. Both units remain at 100 percent power. The NRC Resident Inspector has been notified. 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).
At 1007 EDT, Watts Bar terminated the notification of unusual event. The basis for termination was that no fire or damaged plant equipment was found. The NRC Resident Inspector has been notified. Notified R2DO (Miller), IR-MOC (Crouch), 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).
Watts Bar Nuclear Plant (WBN) is retracting Event Notice 56809, Notice of Unusual Event, based on the following additional information, not available at the time of the initial notification. Specifically, in accordance with the emergency preparedness implementing procedures, WBN reported a condition that was determined to meet emergency action level (EAL) HU4, Initiating criteria number 1, receipt of multiple (more than 1) fire alarms or indicators and the fire was within any Table H2 plant area, which includes the diesel generator building. It was further determined that multiple fire detection zones actuated (spurious and invalid) enabling the discharge of installed fire suppression (CO2) into the space. Upon entry by the site fire brigade, it was determined that no smoke or fire existed and reported to the Shift Manager at 0930 EDT. All fire alarms were reset. Troubleshooting activities are in progress to determine the cause. A fire watch has been established and CO2 has been isolated. The required compensatory measures for the affected areas will remain in place until completion of the investigation, and CO2 suppression is restored to functional. Notified R2DO (Miller), IR-MOC (Crouch), NRR-EO (Felts), DHS-SWO (email), FEMA Ops Center (email), CISA Central (email), FEMA NWC (email), CWMD Watch Desk (email), DHS NRCC THD Desk (email), and DHS Nuclear SSA (email). | ||
| ENS 56804 | 19 October 2023 19:58:00 | Prairie Island | NRC Region 3 | Westinghouse PWR 2-Loop | The following information was provided by the licensee via phone and email: Reporting due to loss of emergency preparedness capabilities. Seismic monitoring capability is non-functional due to loss of power. These monitors do not have a credited compensatory measure. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The NRC Resident Inspector has been notified. The licensee intends to notify state and local officials. | ||
| ENS 56803 | 19 October 2023 15:15:00 | Prairie Island | NRC Region 3 | Westinghouse PWR 2-Loop | Steam Generator Reactor Protection System Auxiliary Feedwater Control Rod | The following information was provided by the licensee via email: On 10/19/2023, at approximately 1110 (CST), with Unit 1 in mode 1 at 100 percent power, the reactor automatically tripped. All control rods fully inserted into the core following the trip. All safety functions operated as designed. The cause of the trip is being investigated. Operations responded and stabilized the plant. Auxiliary feedwater actuated as expected. Decay heat is being removed by the steam generator through the steam generator power operated relief valve. The trip was complex as non-safety related power was lost to both Unit 1 and Unit 2. Unit 1 is currently in mode 3 and on natural recirculation as both reactor coolant pumps are without power. Unit 2 is currently in a refueling outage with all fuel in the spent fuel pool (SFP). SFP cooling was lost for approximately 70 minutes. No impacts to the SFP temperature were observed. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Due to the actuation of the auxiliary feedwater system following the reactor trip, this event is being reported as a specified system actuation in accordance with the reporting criteria of 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 second paragraph of the original report is amended as follows to correct information regarding the spent fuel pool for Unit 2: Unit 2 is currently in a refueling outage with all fuel in the spent fuel pool (SFP). SFP cooling was maintained at all times with one train of SFP cooling. The second train lost power and was restarted approximately 70 minutes (after power was lost). No impacts to the SFP temperature were observed. Notified R3DO (Orth) and IR MOC (Crouch) and NRR EO (Felts) via email | |
| ENS 56802 | 18 October 2023 15:18:00 | McGuire | NRC Region 2 | Westinghouse PWR 4-Loop | Steam Generator Feedwater Auxiliary Feedwater | 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 | Emergency Diesel Generator | 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 56790 | 12 October 2023 23:31:00 | Ginna | NRC Region 1 | Westinghouse PWR 2-Loop | Reactor Protection System Control Rod Auxiliary Feed Water Main Steam | Manual Scram | 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. |