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| Start date | Site | Title | Description | System | |
|---|---|---|---|---|---|
| ENS 57181 | 18 June 2024 20:40:00 | Perry | Inoperability of Division 3 Diesel Generator Supporting High Pressure Core Spray | The following information was provided by the licensee via phone and email: At 1640 EDT on 06/18/2024, the division 3 diesel generator was declared inoperable. This condition could prevent 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). All other emergency core cooling systems 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. The division 3 diesel generator was declared inoperable due to potential water intrusion into the electrical generator. Inspection of the generator is in progress. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: This event resulted in Perry Unit 1 entering a 72 hour limiting condition for operation (LCO) in accordance with Technical Specification 3.8.1. condition 'B'. | High Pressure Core Spray Emergency Core Cooling System |
| ENS 57139 | 23 May 2024 12:51:00 | River Bend | Fitness for Duty Programmatic Failure | The following information was provided by the licensee via email: During a security inspection, it was determined that some past events at Entergy sites that were not reported may have met the reporting criterion of 10 CFR 26.719(b)(4). As a result, the following events at River Bend Station, Unit 1 are now being conservatively reported: On March 21, 2023, a condition report was written to document that an individual who should have been placed in a follow-up fitness for duty (FFD) program was not tested according to this program. On May 11, 2023, a subsequent condition report was written to document that a different individual who should have been placed in a follow-up FFD program was not tested according to this program. The resident inspector has been notified. | |
| ENS 57138 | 23 May 2024 12:51:00 | Grand Gulf | Fitness for Duty Programmatic Failure | The following information was provided by the licensee via email: During a security inspection, it was determined that some past events at Entergy sites that were not reported may have met the reporting criterion of 10 CFR 26.719(b)(4). As a result, the following event at Grand Gulf, Unit 1 is now being conservatively reported: On May 11, 2023, a condition report was written to document that an individual who should have been placed in a follow-up fitness for duty program was not tested according to this program. The resident inspector has been notified. | |
| ENS 57136 | 23 May 2024 08:00:00 | Perry | Technical Specification Required Shutdown | The following information was provided by the licensee via email: At 0400 EDT on May 23, 2024, a technical specification required shutdown was initiated at Perry. Technical specification action 3.4.5 condition B (unidentified reactor coolant system leakage exceeds 5 gallons per minute) was entered on May 23, 2024 at 0000 with a required action to reduce leakage to within limits within 4 hours, due by 0400 on May 23, 2024. This required action was not completed within the completion time, therefore, a technical specification required shutdown was initiated, and this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(i). 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 reactor coolant leakage was stable at approximately 6 gallons per minute. | Reactor Coolant System |
| ENS 57130 | 16 May 2024 12:40:00 | Perry | Reactor Water Cleanup System Isolation Channel Inoperable | The following information was provided by the licensee via email: On May 16, 2024 at 0840 EDT, operations declared the reactor water cleanup (RWCU) leak detection instruments related to the high differential flow signal inoperable. Technical specification (TS) 3.3.6.1, primary containment and drywell isolation instrumentation, conditions `A and `B were entered as one required channel of instrumentation was inoperable, and an automatic function with isolation capability was not maintained. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). All other RWCU primary containment isolation instrumentation functions remained operable. At 1210 EDT, the affected leak detection instruments were declared operable, and the TS limiting condition for operation 3.3.6.1 was declared met. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Primary containment Reactor Water Cleanup |
| ENS 57206 | 14 May 2024 00:28:00 | River Bend | Invalid Partial Containment Isolation | The following information was provided by the licensee via phone and email: At 1928 CDT on May 13, 2024, River Bend Station (RBS) was operating in Mode 1 at 100 percent power when an invalid isolation signal actuated multiple containment isolation valves in more than one system. The invalid isolation signal was caused by voltage perturbations on the offsite power distribution system due to multiple lightning strikes in the vicinity of RBS. The event caused one containment isolation valve to isolate in the floor and equipment drains system, and two containment isolation dampers to isolate in the auxiliary building ventilation system. This event was a partial system isolation for the affected systems and did not result in a full train actuation. This event meets the reportable criteria for 10 CFR 50.73(a)(2)(iv)(A) and is being reported as any event or condition that resulted in manual or automatic actuation of any systems listed in paragraph (a)(2)(iv)(B). This notification is being provided in lieu of a Licensee Event Report as indicated in 10 CFR 50.73(a)(1). The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The valve and dampers were immediately re-opened. The standby gas treatment system automatically initiated due to the closure of the containment isolation dampers in the auxiliary building ventilation system. | Standby Gas Treatment System |
| ENS 57092 | 25 April 2024 21:55:00 | Perry | Configuration of B and C Residual Heat Removal Loops in an Unanalyzed Condition | The following information was provided by the licensee via phone and email: On April 25, 2024, it was determined that between March 25, 2024, 2015 (EDT) and March 30, 2024, 2024 (EDT), the condensate transfer and storage system was employed as a method of alternate keepfill in place of the installed residual heat removal (RHR) systems waterleg pump for RHR system loops `B and `C. This condition is not bounded by existing design and licensing documents. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Residual Heat Removal |
| ENS 57053 | 26 March 2024 16:15:00 | Grand Gulf | Actuation of Reactor Protection System | The following information was provided by the licensee via phone and email: On March 26, 2024 at 1115 CDT, Grand Gulf Nuclear Station experienced an actuation of the reactor protection system (RPS) due to high reactor coolant system pressure. The plant was in Mode 4 at zero percent power and performing scram time testing. All rods were fully inserted at the time of the RPS actuation, and all required equipment responded as designed. This actuation is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A). The cause of the event is under investigation. The NRC resident inspector has been notified. | Reactor Coolant System Reactor Protection System |
| ENS 57050 | 25 March 2024 15:27:00 | Clinton | Fitness for Duty | The following information was provided by the licensee via email and phone call: At 1027 CDT on 3/25/24, it was determined that a contract supervisor tested positive in accordance with the fitness for duty testing program. The individuals authorization for site access has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 56938 | 29 January 2024 16:05:00 | Grand Gulf | High Pressure Core Spray Failure | 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. | High Pressure Core Spray |
| ENS 56914 | 5 January 2024 20:52:00 | Perry | Offsite Notification | 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 56894 | 16 December 2023 09:50:00 | Grand Gulf | Automatic Scram Due to Turbine Trip | 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. | Feedwater Reactor Protection System Control Rod |
| ENS 56887 | 13 December 2023 07:02:00 | River Bend | Automatic Reactor 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. | Feedwater Reactor Protection System Reactor Core Isolation Cooling |
| ENS 56863 | 18 November 2023 05:55:00 | River Bend | Manual Reactor 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. | Feedwater Reactor Protection System Emergency Diesel Generator Control Rod |
| ENS 56825 | 31 October 2023 13:00:00 | River Bend | False Negative on Blind Performance Sample | 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 56745 | 19 September 2023 01:07:00 | Clinton | Offsite Notification | The following information was provided by the licensee via email: On 9/18/2023 at 2007 CDT, Clinton reported to the Illinois Emergency Management Agency, National Response Center and DeWitt County a hazardous substance release of 1300 gallons of Sodium Bisulphite. The release was at the site's flume discharge building due to a crack on a fitting inside the building. This release did not exceed any NRC regulations or reporting criteria. This notification is being made solely as a four-hour, non-emergency notification for a Notification of Other Government Agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56724 | 6 September 2023 20:00:00 | Grand Gulf | Controlled Substance Found in Protected Area | The following information was provided by the licensee via email: On September 6 at 15:00 CDT, Grand Gulf Nuclear Station personnel identified a bottle of vanilla extract in a kitchen area located within the Protected Area. Ingredients were listed as 'pure vanilla extract in water and alcohol. The percentage by volume of alcohol was not specified. It was subsequently determined that the alcohol by volume was likely 35 percent. The NRC Resident Inspector has been notified. | |
| ENS 56696 | 24 August 2023 02:00:00 | Grand Gulf | Fitness for Duty (FFD) Report - NON-LICENSED Supervisor Violated FFD Policy | The following information was provided by the licensee via email: On August 23, 2023 at 2100 CDT, Grand Gulf Nuclear Station was notified that a non-licensed supervisor violated the station's Fitness for Duty policy. The employee's unescorted access at Grand Gulf Nuclear Station has been terminated. This event was determined to be reportable under 10 CFR 26.719(b)(2)(ii). The NRC Resident Inspector has been notified. | |
| ENS 56673 | 10 August 2023 04:39:00 | Perry | Automatic Reactor Trip | The following information was provided by the licensee via email: At 0039 (EDT) on 8/10/23, with Unit 1 in Mode 1 at 100 percent power, the reactor automatically tripped during a reactor protection system (RPS) bus shift. All systems responding normally post-trip. There was no equipment inoperable at the time of the trip. Operations responded and stabilized the plant. Reactor water level being maintained via feedwater. Decay heat is being removed by cycling safety relief valves. An actuation of high-pressure core spray, division 3 diesel generator, and reactor core isolation cooling occurred during the scram and main steam line isolation closure. The reason for the auto-start was reaching Level 2 (130 inches in the reactor pressure vessel) during the transient. The systems automatically started as designed and injected to the reactor vessel when the Level 2 signal was received. The RPS actuation is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). The emergency core cooling system (ECCS) injection is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). The ECCS actuation is being reported as a eight-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Feedwater Reactor Protection System Reactor Core Isolation Cooling Reactor Pressure Vessel Core Spray Emergency Core Cooling System Main Steam Line Safety Relief Valve |
| ENS 56641 | 18 July 2023 20:14:00 | River Bend | Part 21 Report - Motor Driven Relay Failed Testing | The following information is a synopsis provided by the licensee via email: River Bend Station completed an internal Part 21 evaluation concerning a motor driven relay that failed pre-installation testing due to a buildup of corrosion between the rotor and relay core. The relay was planned for use in the Remote Shutdown System. The NRC Resident has been notified. A written notification will be provided within 30 days. Affected known plants include only River Bend at the time of the notification. | Remote shutdown |
| ENS 56598 | 29 June 2023 13:07:00 | Grand Gulf | FITNESS-FOR-DUTY Report | The following information was provided by the licensee via email: A non-licensed supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 56588 | 23 June 2023 19:21:00 | Perry | Offsite Notification - Environmental | The following information was provided by the licensee via email: At 1521 EDT on 6/23/2023, 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 did not exceed any NRC regulations or reporting criteria. Tritium has not been detected in any other locations and is not expected to impact groundwater or exceed any limits in the Off Site Dose Calculation Manual (ODCM). 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. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The following agencies were notified by licensee: Lake County Emergency Management Agency (EMA) Ashtabula County EMA Geauga County Department of Emergency Services Ohio EMA Radiological Branch | |
| ENS 56491 | 26 April 2023 15:48:00 | River Bend | Fitness for Duty Report | A non-licensed supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 56455 | 6 April 2023 20:46:00 | Perry | Main Steam Line 'B' Leakage in Excess of Tech Spec Limits | The following information was provided by the licensee via phone and email: On March 4, 2023, it was determined that the main steam line (MSL) local leak rate test results for MSL 'B' were in exceedance of technical specification (TS) surveillance requirement (SR) 3.6.1.3.10 limits. Additionally, the leakage at the outboard main steam isolation valve (MSIV) 'B', was indeterminate due to a gross packing gland leak. An engineering calculation dated April 6, 2023, showed that this leakage, in conjunction with a design basis loss of coolant accident, would result in the radiological dose exceeding Updated Safety Analysis Report limits to the exclusion area boundary, the low population zone, and the control room. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) as a condition that results in the power plant being in an unanalyzed condition that degrades plant safety. Both inboard and outboard 'B' MSIVs have been reworked and are within the TS SR limits. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Main Steam Isolation Valve Main Steam Line |
| ENS 56417 | 17 March 2023 02:26:00 | Perry | Failed FITNESS-FOR-DUTY Test | The following information was provided by the licensee via email: On March 16, 2023, at 2226 EDT, a site supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's authorization for access to the plant has been terminated. The Resident Inspector has been notified. | |
| ENS 56428 | 14 March 2023 14:26:00 | River Bend | FITNESS-FOR-DUTY Report - Subversion of the FFD Process | A non-licensed contract supervisor was confirmed to have violated the FFD policy by attempting to subvert the testing process. The individual's authorization for site access was immediately terminated. The licensee notified the R4 Branch Chief (Josey)
The following information was provided by the licensee via email: The Medical Review Officer (MRO) was provided with additional information on the collection process in question. Based on this additional information, the MRO was unable to conclude with a high degree of certainty that an attempt to subvert the FFD collection process had occurred." Notified R4DO (Gaddy) and via email the FFD Group. | |
| ENS 56390 | 5 March 2023 05:00:00 | River Bend | Transport of a Potentially Contaminated Person Offsite | The following information was provided by the licensee via email: At 2300 CST on March 4, 2023, River Bend Station (RBS) was shut down in Mode 5 when 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 56356 | 6 February 2023 11:30:00 | Clinton | Loss of Communications and Assessment Capabilities | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. | |
| ENS 56328 | 1 February 2023 05:43:00 | Clinton | Automatic Scram Due to Turbine Trip | The following information was provided by the licensee via fax and telephone: Generator trip due to power load unbalance which caused a turbine trip and subsequent reactor scram. Experienced a trip on circulating water pump A. NRC Resident Inspector notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Off-site power available and unaffected. Decay heat removal via main steam line and drains to condenser. Plant is stable in mode 3. | Decay Heat Removal Main Steam Line |
| ENS 56298 | 5 January 2023 17:42:00 | Perry | Automatic Reactor Scram | The following information was provided by the licensee via phone and email: At 1242 (EST) on 05 January 2023, with the Unit in Mode 1 at 99 percent power, the reactor automatically tripped on low Reactor Pressure Vessel level while restoring power to Digital Feedwater Control Stations when there was a perturbation to the level controls. The reason for perturbation is unknown at this time. The trip was not complex, with all systems responding normally post trip. Operations responded and stabilized the plant. High pressure core spray was manually initiated in accordance with site procedures. Reactor water level is being maintained via the Feedwater System. Decay heat is being removed by the Main Condenser. 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)(A) and 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. | Feedwater Reactor Protection System Reactor Pressure Vessel High Pressure Core Spray Main Condenser |
| ENS 56282 | 20 December 2022 03:01:00 | Grand Gulf | Manual Scram Due to Loss of Feedwater Pump | The following information was provided by the licensee via email: At 2101 (CST) on December 19, 2022, a manual reactor scram was initiated at Grand Gulf Nuclear Station (GGNS). Following the reactor scram, the high pressure core spray (HPCS) system was used to maintain reactor water level. The manual (reactor protection system) RPS actuation is being reported in accordance with 10 CFR 50.72(b)(2) and the HPCS actuation is being reported in accordance with 10 CFR 50.72(b)(3). At 2058, GGNS experienced a loss of a condensate booster pump. At 2101, the `A' reactor feedwater pump tripped and the reactor was manually scrammed. All control rods were fully inserted into the core. At 2104, the `B' reactor feedwater pump tripped and HPCS was manually started. HPCS was manually injected to maintain reactor water level at 2121. The `A' reactor feedwater pump was successfully restarted at 2126. GGNS is currently in Mode 3. Reactor level is being maintained with the `A' reactor feedwater pump and pressure is being maintained with the turbine bypass valves. The NRC Resident Inspector was notified. | Feedwater High Pressure Core Spray Control Rod |
| ENS 56185 | 27 October 2022 17:28:00 | Grand Gulf | Secondary Containment Inoperable During Surveillance | The following information was provided by the licensee via email: At 1228 CDT on October 27, 2022, Grand Gulf Nuclear Station (GGNS) was in Mode 1 at 88 percent power when a failure of a draw down surveillance resulted in the loss of secondary containment. During the performance of the surveillance GGNS was unable to maintain secondary containment pressure, as required by Technical Specification Surveillance Requirement 3.6.4.1.4, greater than or equal to 0.266 inches of water vacuum for 1 hour at a flow rate of less than or equal to 4000 cfm. The test was secured. Secondary containment was declared inoperable and Technical Specification 3.6.4.1 A.1 was entered at 1228 CDT. Secondary containment was restored to operable status at 1240 CDT by restoring the configuration to a previously known operable condition. This event is being reported as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector was notified. | Secondary containment |
| ENS 56171 | 20 October 2022 09:27:00 | Grand Gulf | Secondary Containment Inoperable During Surveillance | The following information was provided by the licensee via email: At 0427 CDT on October 20, 2022, Grand Gulf Nuclear Station (GGNS) was in Mode 1 at 100 percent power when a failure of a draw down surveillance resulted in the loss of secondary containment. During the performance of the surveillance GGNS was unable to maintain secondary containment pressure, as required by Technical Specification Surveillance Requirement 3.6.4.1.4, greater than or equal to 0.266 inches of water vacuum for 1 hour at a flow rate of less than or equal to 4000cfm. The test was secured. Secondary containment was declared inoperable and Technical Specification 3.6.4.1 A.1 was entered at 0427 CDT. Secondary containment was restored to operable status at 0520 CDT by restoring the configuration to a previously known operable condition. This event is being reported as an event or condition that could have prevented the fulfillment of a safety function. The NRC Resident Inspector was notified. | Secondary containment |
| ENS 56118 | 19 September 2022 21:30:00 | Grand Gulf | Offsite Notification Due to Fatality | The following information was provided by the licensee via email: At approximately 1520 CDT on September 19, 2022, Grand Gulf Nuclear Station (GGNS) requested transport for treatment of a non-responsive individual, a contract employee, to an offsite medical facility. The offsite medical facility notified GGNS at approximately 1630 CDT that the individual had been declared deceased. The fatality was not work-related, and the individual was outside of the Radiological Control Area. This is a four-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(xi) related to the notification of a government agency. The contractor's employee will be notifying the Occupational Safety and Health Administration. The NRC Senior Resident Inspector has been notified. | |
| ENS 56116 | 19 September 2022 06:32:00 | River Bend | Safety System Inoperability | The following information was provided by the licensee via email: At 0132 CDT on September 19, 2022, River Bend Station (RBS) was operating at 100% power when the high pressure core spray (HPCS) system was declared inoperable in accordance with technical specification 3.8.9, condition E (declare HPCS and standby service water system pump 2C inoperable immediately) due to a E22-S003, HPCS transformer feeder malfunction. The HPCS is a single train system at RBS, therefore this event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfilment of a safety function. The reactor core isolation cooling system has been verified to be operable. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: RBS has entered a 14-day limiting condition for operation due to the loss of HPCS and they have upgraded their on-line plant risk model to "yellow". | Service water Reactor Core Isolation Cooling High Pressure Core Spray |
| ENS 56059 | 20 August 2022 04:42:00 | Grand Gulf | Technical Specification Required Shutdown | The following information was provided by the licensee via fax or email: At 2342 CDT on August 19, 2022, with Grand Gulf Nuclear Station in Mode 1 and at 40 percent power, the station initiated a normal shutdown to comply with its Technical Specifications (TS). The station entered Mode 3 at 0000 CDT August 20, 2022 to comply with (LCO) 3.5.1 Condition G Action G.1 due to the condition reported to NRC previously (EN 56058). This event is being reported under 10 CFR 50.72(b)(2)(i) as a shutdown required by the plant's technical specifications. The NRC Senior Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The plant is now in a 36-hour LCO to be in Mode 4 due to Low Low Set Valves inoperability per TS 3.6.1.6.
Grand Gulf Nuclear Station (GGNS) is performing this notification to retract event EN 56059 that was reported on August 20, 2022. Previously, GGNS notified the NRC that it had initiated a shutdown required by Technical Specifications to comply with Limiting Condition of Operation (LCO) 3.5.1 Condition G.1 due to the inoperability of four Automatic Depressurization System (ADS) valves. Following the shutdown, GGNS completed walkdowns and determined that the condition affected only one ADS valve. As a result, the shutdown to satisfy the required actions of TS LCO 3.5.1 Condition G.1 was not required. The NRC Resident Inspector has been notified of the retraction. R4DO (Kellar) was notified. | Automatic Depressurization System |
| ENS 56058 | 19 August 2022 17:15:00 | Grand Gulf | Four Automatic Depressurization System Valves Inoperable | The following information was provided by the licensee via email: At 1215 CDT on 8/19/2022, with Grand Gulf Nuclear Station in Mode 1 and at 100 percent power, four Automatic Depressurization System (ADS) valves were rendered inoperable due to a loss of system pressure. The station entered Technical Specification 3.5.1 Condition G. This event is being reported under 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. There were no other systems affected as a result of this condition. The NRC Senior Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Plans are to remain in Mode 1 until corrected or until driven by the Technical Specifications to shut down (12-hour LCO from 1215 CDT on 8/19/2022).
Grand Gulf Nuclear Station (GGNS) is performing this notification to retract event EN 56058 that was reported on August 19, 2022. Previously, GGNS notified the NRC that four Automatic Depressurization System (ADS) valves were inoperable due to a loss of system pressure. Based upon further investigation, the condition reported in EN 56058 was found to affect only a single ADS valve. As a result, it was determined that an event or condition that could have prevented the fulfillment of a safety function did not exist at GGNS. Sufficient redundancy existed to perform the safety function. The NRC Resident Inspector has been notified of the retraction. R4DO (Kellar) was notified. | Automatic Depressurization System |
| ENS 55973 | 30 June 2022 19:45:00 | Grand Gulf | Manual Scram Due to Loss of Transformer | The following information was provided by the licensee via phone and email: At 1445 (CDT) on June 30, 2022, with Grand Gulf Nuclear Station in Mode 1 and at 100 percent power, the reactor was manually scrammed due to the loss of balance of plant (BOP) transformer 23. All control rods fully inserted into the core and all systems responded appropriately. Reactor level is being maintained with condensate and feedwater. Reactor pressure is being maintained with turbine bypass valves. The cause of the loss of BOP transformer 23 is under investigation at this time. Standby Service Water 'A' and 'B' were manually initiated to supply cooling to Control Room A/C, ESF switchgear room coolers, and plant auxiliary loads. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B) as an event or condition that resulted in actuation of the Reactor Protection System and 10 CFR 50.72(b)(3)(iv)(A) due to the actuation of Standby Service Water. The NRC Senior Resident Inspector was notified. | Feedwater Service water Reactor Protection System Control Rod |
| ENS 55962 | 24 June 2022 16:57:00 | Perry | LOW Pressure Core Spray Inoperable | The following information was provided by the licensee via telephone: At 1257 EDT on June 24, 2022, it was discovered the Low Pressure Core Spray System (LPCS) was INOPERABLE. At Perry, the Low Pressure Core Spray System is considered a single train system in Modes 1, 2, and 3; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Inoperability of the Low Pressure Core Spray system was caused by a loss of power to the LPCS Minimum Flow Valve during surveillance activities. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Core Spray |
| ENS 55915 | 26 May 2022 11:30:00 | Grand Gulf | Spurious Siren Actuation | The following information was provided by the licensee via phone and email: On May 26, 2022, at 0753 CDT, the Grand Gulf Nuclear Station was notified of a spurious actuation of a single Alert Notification System siren in Tensas Parish, Louisiana. The actuation occurred during siren testing conducted at approximately 0630 CDT - no emergency conditions are present at Grand Gulf Nuclear Station. A press release from Entergy is not planned at this time. This condition is reportable under 10 CFR 50.72(b)(2)(xi) as a notification of an offsite government agency. The NRC Senior Resident Inspector has been notified. | |
| ENS 55561 | 3 November 2021 17:08:00 | Grand Gulf | FITNESS-FOR-DUTY Report | A non-licensed employee had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 55451 | 9 September 2021 05:33:00 | Grand Gulf | High Pressure Core Spray Inoperable | At 0033 CDT on September 9, 2021, Grand Gulf Nuclear Station (GGNS) was operating at 70 percent power when the High Pressure Core Spray (HPCS) was declared inoperable. The inoperability determination was made due to control room annunciations. In accordance with GGNS Technical Specification 3.5.1.B.1, the Reactor Core Isolation Cooling system was verified to be operable. Troubleshooting is in progress. This 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. The NRC Resident Inspector has been notified. | Reactor Core Isolation Cooling High Pressure Core Spray |
| ENS 55172 | 6 April 2021 01:49:00 | Perry | Manual Reactor Protection System (RPS) Actuation at Zero Percent Power | At 2149 EDT on April 5, 2021, with the power plant in Mode 2 at zero percent power, an actuation of the RPS system occurred following the decision to abort plant start-up. The reason for the RPS actuation was to align the plant to Mode 3, from Mode 2, following manually inserting all control rods using the Rod Control System. The RPS system initiated as designed when the mode switch was taken from 'Start-up' to 'Shutdown' to align the plant to Mode 3 from Mode 2. 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 RPS system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
This is a retraction of an event notification made on 4/6/2021 at 0432 EST (EN#55172). This event was initially reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the RPS System. This event was later determined to be pre-planned, in accordance with Technical Specifications, and not the result of a significant event, therefore not meeting the reporting criteria of 10 CFR 50.72(b)(3)(iv)(A). On the evening of April 4, 2021, while commencing reactor start up, it was determined that control rod withdrawal to add positive reactivity for the start-up would not overcome the negative reactivity of plant heat up. The control room team determined that the proper course of action would be to insert all control rods . The control room briefed and notified the Outage Control Center about its decision, then proceeded to insert all control rods. The control room manually inserted all control rods using the control rod hydraulic system. Following insertion of all control rods, the mode switch was taken to the shutdown position to meet the prerequisites of the procedure for maintaining hot shutdown. This action establishes Mode 3 in accordance with Technical Specifications and aligns the plant to perform the necessary work prior to a plant restart. By placing the mode switch in the shutdown position, a scram signal is generated for 10 seconds. NUREG-1022 offers guidance that states 'Actuations that need not be reported are those initiated for reasons other than to mitigate the consequences of an event.' The actions the operating crew took that night are accurately described by this statement in NUREG-1022 'shifting alignment of makeup pumps or closing a containment isolation valve for normal operational purposes would not be reportable.' In this situation, the Mode switch was taken to shutdown to align the plant to mode 3 for normal operational purposes, and not to mitigate a significant event. When the mode switch was taken to shut-down, RPS initiated as designed, there was no mis-operation or unnecessary actuation. This actuation was determined to be pre-planned, in accordance with Tech Specs, and not the result of a significant event, therefore not meeting the reporting criteria of 10 CFR 50.72(b)(3)(iv)(A). The NRC Resident has been notified. Notified R3DO (McGraw). | Reactor Protection System Control Rod |
| ENS 55169 | 2 April 2021 15:17:00 | River Bend | Automatic Reactor Scram Due to Turbine Trip | At 1017 CDT on April 2, 2021, while operating at 85 percent 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. 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 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 level 3 isolations. No radiological releases have occurred due to this event from the unit. The NRC Resident Inspector has been notified of this event. | Feedwater Reactor Protection System |
| ENS 55154 | 25 March 2021 14:18:00 | River Bend | Manual Reactor Trip Due to Lowering Condenser Vacuum | On March 25, 2021 at 0901 CDT, River Bend Station Unit 1 (RBS) was operating at 93 (percent) reactor power (limited by 100 (percent) recirculation flow) when condenser vacuum began to lower due to ARC-AOV1A, Steam Jet Air Ejector Suction Valve, going closed. At 0918 CDT, a manual reactor SCRAM was inserted at approximately 80 (percent) reactor power due to condenser vacuum continuing to lower. After the SCRAM, all systems responded as designed and condenser vacuum was restored by starting a mechanical vacuum pump. The cause of the Steam Jet Air Ejector Suction Valve closure is unknown at this time and being investigated. Currently RBS is stable, and pressure is being maintained using Turbine Bypass Valves. The Main Steam Isolation Valves remained opened throughout the event. 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 level 3 isolations. No radiological releases have occurred due to this event from the unit. NRC Resident Inspector has been notified of this event. | Reactor Protection System Main Steam Isolation Valve Steam Jet Air Ejector |
| ENS 55263 | 23 March 2021 04:37:00 | Perry | 60-Day Optional Telephonic Notification for an Invalid Diesel Generator Initiation | This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid specific system actuation. On March 23, 2021, during the performance of the Division 1 ECCS ((Emergency Core Cooling System)) Integrated Test, the Division 1 Diesel Generator (DG) unexpectedly started. While performing the local lockout testing, per the procedure, a step was performed that initiated the unexpected DG start. The following step was to verify the diesel did NOT start. It was later determined that this was a procedural deficiency. The DG started and ran as designed. The DG did not tie to the safety bus as no undervoltage condition was detected. This event is considered an invalid system actuation reportable under 10 CFR 50.73(a)(2)(iv)(A). The actuation was not initiated in response to actual plant conditions or parameters and was not a manual initiation. Therefore, this notification is provided via a 60-day optional phone call in accordance with 10 CFR 50.73(a)(1) instead of submitting a written Licensee Event Report. All affected systems functioned as expected in response to the actuation. The DG was shut down in accordance with plant procedures and the testing procedure corrected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Emergency Core Cooling System |
| ENS 56192 | 22 February 2021 05:00:00 | Grand Gulf | Part 21 - Outer Containment Personnel Airlock Leakage | The following information was provided by the licensee via email: On February 22, 2021 while in Mode 1 and at 100 percent power, Grand Gulf Nuclear Station (GGNS) identified through surveillance testing that the 208 foot elevation outer containment personnel airlock door failed its technical specification leakage test. Analysis indicated that the airlock equalizing valves were leaking due to lack of lubrication during installation. Subsequent analysis determined that the lubrication was to have been performed during a vendor's qualification / dedication process. GGNS completed a substantial safety hazard Evaluation and determined that the failure to lubricate the valve components constituted a substantial safety hazard. The NRC Resident (Inspector) has been notified. This is a non-emergency notification required by 10 CFR 21.21(d)(3)(i). A written notification will be provided within 30 days. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: This condition has been corrected. This report is submitted to meet 10 CFR Part 21 reporting requirements. | |
| ENS 55056 | 7 January 2021 07:24:00 | Grand Gulf | Unusual Event Declared Due to Rise in Drywell Unidentified Reactor Coolant System Leakage | An Unusual Event was declared at Grand Gulf Nuclear Station at 0124 (CST) on 01/07/2021 due to Unidentified Drywell Leakage exceeding 10 GPM for 15 minutes. Unidentified leakage has reduced to less than 0.44 GPM as of 0213 CST on 01/07/2021. The cause of the increase leakage rate is under investigation. The licensee notified the NRC Resident Inspector. Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).
At 0356 CST, Grand Gulf Nuclear Station terminated the Unusual Event following plant parameters returning to normal. The current leakage rate is 0.3 gallons per minute and stable. The NRC Resident Inspector has been notified. Notified R4DO (Kozal), IRD MOC (Gott), NRR EO (Felts), DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email). | Reactor Coolant System |
| ENS 55030 | 11 December 2020 18:04:00 | Grand Gulf | Automatic Reactor Scram Due to Main Turbine / Generator Trip | On December 11, 2020 at 1204 CST, Grand Gulf Nuclear Station (GGNS) experienced an Automatic Reactor Scram from 100 percent Reactor Power after a Main Turbine and Generator Trip. All Control Rods fully inserted and there were no complications. All systems responded as designed. Reactor pressure is being maintained with Main Turbine Bypass Valves. Reactor water level is being maintained in normal band with the condensate system. No radiological releases have occurred due to this event from the unit. The NRC Branch Chief has been notified. | Main Turbine Control Rod |
| ENS 55012 | 30 November 2020 13:00:00 | River Bend | Fitness for Duty Report | A non-licensed employee supervisor had a confirmed positive for a controlled substance. The employee's access to the plant has been terminated. The licensee informed the NRC Resident Inspector. |