Semantic search

Jump to navigation Jump to search
 Entered dateSiteRegionReactor typeEvent description
ENS 5622013 November 2022 04:01:00CooperNRC Region 4GE-4The following information was provided by the licensee email: On November 12, 2022, at 2319 CST, an actuation of the reactor protection system (RPS) initiated a full scram. The plant was in Mode 2, reactor pressure was 149 pounds. The high pressure coolant injection (HPCI) injection valve, HPCI-MOV-MO19, opened and injected cold water into the reactor vessel while HPCI system testing was in progress. The cause is still under investigation. All control rods inserted. Plant is currently in Mode 3 and stable. All systems operated as designed with no Primary Containment Isolation System group isolations. This event is being reported under two event classifications: 50. 72(b)(2)(iv)(B) -- "Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. 50. 72(b)(3)(iv)(A) -- "Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. The NRC Resident has been informed.
ENS 562149 November 2022 15:37:00WaterfordNRC Region 4CEA non-licensed supervisor had a confirmed positive 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 562023 November 2022 14:05:00WaterfordNRC Region 4CEThe following information was provided by the licensee via email: This 60-day telephonic notification is being made in lieu of a licensee event report submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid engineered safety feature actuation signal. On September 6, 2022, at Waterford 3, while performing a plant protection system (PPS) power supply check, technicians observed an abnormally high voltage output. When the technicians opened the PPS bay cabinet door to adjust the voltage, they then observed low voltage indications. The direct cause of this issue is believed to be vibration induced relay chattering or an intermittent connection issue when opening the rear doors of PPS cabinets. This resulted in half the logic being met for the Engineered Safety Feature Actuation Signal (ESFAS) signals to fully actuate. The ESFAS signal opened the following valves: EFW-228A (EFW to SG 1 Primary Isolation), EFW-229A (EFW to SG 1 Backup Isolation), EFW-228B (EFW to SG 2 Primary Isolation) and EFW-229B (EFW to SG 2 Backup Isolation). This was a partial actuation of ESFAS. Affected plant systems functioned successfully. The inadvertent actuation was caused by a spurious signal and was not a valid signal resulting from actual parameter inputs. The 1992 Statements of Consideration define an invalid signal to include spurious signals including jarring of a cabinet door. In accordance with 10 CFR 50.73(a)(1) a telephone notification is being made in lieu of submitting a written licensee event report. The NRC Senior Resident Inspector has been notified. These events did not result in any adverse impact to the health and safety of the public.
ENS 5619231 October 2022 15:29:00Grand GulfNRC Region 4The 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 5618527 October 2022 19:49:00Grand GulfNRC Region 4GE-6The 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.
ENS 5617422 October 2022 17:36:00CooperNRC Region 4GE-4The following information was provided by the licensee via fax: During Mode 5 Refueling operations, while attempting to establish flow through the Fuel Pool Cooling system filter demineralizers, an air operated valve to a radioactive waste tank failed to close automatically. This caused the Fuel Pool Cooling system to pump water from the Skimmer Surge Tanks (SST) to the radioactive liquid waste system. In response to the loss of inventory from the SSTs, the Control Room operating crew started Core Spray Pump A to restore normal operating level In the SST. This prevented the loss of the Fuel Pool Cooling/Alternate Decay Heat Removal system which was the only in service system meeting the safety function of decay heat removal. Core Spray Pump A was used for Injection for less than 3 minutes. This is reportable as a discharge of ECCS into the RCS in response to an event, but not part of a pre-planned sequence under 10 CFR 50.72(b)(2)(iv)(A) and actuation of a specified system under 10 CFR 50.72(b)(3)(Iv)(A). The resident inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Licensee reported approximately 6000-7000 gallons of water was injected into the RCS. The stuck open air operated valve was closed. Proceeding with refueling outage operations.
ENS 5617120 October 2022 11:31:00Grand GulfNRC Region 4GE-6The 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.
ENS 561527 October 2022 05:41:00CooperNRC Region 4GE-4The following information was provided by the licensee via fax: On 10/7/2022 at 0050 CDT, a potentially contaminated individual was transported off-site via ambulance to a local hospital. Due to the nature of the medical condition, an initial on-site survey for radioactive contamination was not performed prior to transport. Prior to arrival at the hospital, it was confirmed the individual and (the individual's) clothing were not radiologically contaminated. Follow-up surveys performed by radiation technicians identified no radiological contamination of the ambulance and response personnel. This event is being reported per 50.72(b)(3)(xii) - 'Any event requiring the transport of a radioactively contaminated person to an offsite medical facility for treatment.' The NRC Resident Inspector has been notified.
ENS 561404 October 2022 15:54:00Arkansas NuclearNRC Region 4CE
B&W-L-LP
A non-licensed supervisor had a confirmed positive 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 561361 October 2022 00:08:00Arkansas NuclearNRC Region 4CE
B&W-L-LP
A supplemental supervisor violated the station's FFD policy. The individuals access to the plant has been terminated. The licensee notified the NRC Senior Resident Inspector.
ENS 5611819 September 2022 19:29:00Grand GulfNRC Region 4GE-6The 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 5611619 September 2022 08:37:00River BendNRC Region 4GE-6The 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".
ENS 5605920 August 2022 02:11:00Grand GulfNRC Region 4GE-6

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.

  • * * RETRACTION ON 10/14/2022 AT 1311 FROM JEFF HARDY TO LAUREN BRYSON * * *

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.

ENS 5605819 August 2022 20:46:00Grand GulfNRC Region 4GE-6

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).

  • * * RETRACTION ON 10/14/22 AT 1311 EDT FROM JEFF HARDY TO KAREN COTTON * * *

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.

ENS 559817 July 2022 22:49:00CooperNRC Region 4GE-4The following information was provided by the licensee via phone and fax: On 7/7/2022, at 0740 CDT, the National Weather Service reported to Cooper Nuclear Station that the NAWAS ((National Warning System)) radio tower near Shubert, Nebraska would neither transmit nor receive. The Shubert Tower transmitter activates the EAS ((Emergency Alert System))/Tone Alert Radios used for public notification. Additional information from the National Weather Service received 7/7/2022 at 1601 (CDT) determined that the Shubert Tower transmitter is non-functional and would not likely be repaired within 24 hours. The backup notification system has been verified to be available throughout this period. This is considered to be a major loss of the Public Prompt Notification System capability. The primary notification system is not expected to be restored to service within 24 hours, and therefore this condition is reportable under 10 CFR 50.72(b)(3)(xiii), since the backup alerting methods do not meet the primary system design objective. The backup notification system is available to use for notifications if needed. The NRC Senior Resident has been informed. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The backup notification system has to be manually activated.
ENS 5597330 June 2022 18:07:00Grand GulfNRC Region 4GE-6The 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.
ENS 5596325 June 2022 00:44:00WaterfordNRC Region 4CEThe following information was provided by the licensee via email: At 2012 CDT, Waterford 3 Steam Electric Station, Unit 3 was operating at 100 percent power when an automatic reactor trip occurred due to Main Steam Isolation Valve MS-124B going closed unexpectedly. Subsequently, both main feedwater isolation valves shut. Emergency Feedwater (EFW) was automatically actuated. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip. The unit is currently stable in Mode 3. All control rods fully inserted as expected and all other plant equipment functioned as expected. This was an uncomplicated scram. This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system (RPS) when the reactor is critical and as an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as valid actuation of the EFW system. The NRC Resident Inspector has been notified.
ENS 5591526 May 2022 10:34:00Grand GulfNRC Region 4GE-6The 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 5590723 May 2022 11:23:00CooperNRC Region 4GE-4The following information was provided by the licensee via email: On May 23, 2022, at 0455 CST, Cooper Nuclear Station experienced a spike in Secondary Containment differential pressure which exceeded the Technical Specifications Surveillance Requirements 3.6.4.1.1 limit of -0.25 inches of water gauge. Secondary Containment differential pressure restored to Technical Specification limits within two minutes and further investigation is ongoing. This unplanned Secondary Containment inoperability constitutes a condition reportable under 10CFR50.72(b)(3)(v)(C) and (D). The NRC Senior Resident Inspector has been informed.
ENS 5571527 January 2022 15:07:00CooperNRC Region 4GE-4

The Licensee provided the following information via email: On January 27, 2022 at 1038 CST, with Cooper Nuclear Station in Mode 1, 100 percent power, the meteorological tower primary and backup data acquisition system failed, which resulted in a loss of meteorological data to the plant. Information technology personnel investigated and restored the primary system to service. Meteorological data to the plant was restored at 1105 CST on January 27, 2022. This notification Is being made due to a loss of emergency assessment capability In accordance with 10 CFR 50.72(b)(3)(xiii). The NRC Resident Inspector has been Informed.

  • * * RETRACTION ON FEBRUARY 23, 2022 AT 1658 EST FROM LINDA DEWHIRST TO LLOYD DESOTELL * * *

The following information was provided by the licensee via fax: This notification is being made to retract event EN 55715 that was reported on January 27, 2022. Based on further investigation, the Emergency Plan and Emergency Plan Implementing Procedures provide acceptable alternative methods for performing emergency assessments that are in addition to the data obtained from the primary and backup meteorological tower information. It was determined that no actual or potential major loss of emergency assessment capability existed per 10 CFR 50.72(b)(3)(xiii). This is consistent with NUREG 1022, Revision 3, Supplement 1 and NEI 13-01, Revision 0. The NRC Resident Inspector has been notified of the retraction. Notified R4DO (O'Keefe)

ENS 5570313 January 2022 12:03:00CooperNRC Region 4GE-4The following information was provided by the licensee via fax: On 1/13/2022 at 0806 CST, Nebraska Public Power District was notified by Atchison County Missouri of a spurious actuation of (Cooper Nuclear Station) (CNS) Emergency Siren 2113 near Rockport, Missouri from approximately 0800 to 0805 CST. Nebraska Public Power District will issue a press release for this event. The CNS Emergency Alert System (EAS) was not activated. This condition is reportable under 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 NRC Senior Resident Inspector has been informed.
ENS 5561429 November 2021 18:47:00Arkansas NuclearNRC Region 4B&W-L-LPOn November 29, 2021 at 1458 CST, Arkansas Nuclear One, Unit 1, (ANO-1) automatically tripped due to high Reactor Coolant System pressure after the 'A' Main Feedwater Pump was manually tripped due to lowering speed. ANO-1 is currently stable in MODE 3 (Hot Standby) maintaining pressure and temperature with the P-75 Auxiliary Feedwater pump and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) for the Reactor Protection System actuation. The NRC Senior Resident Inspector has been notified. Unit 2 was not affected.
ENS 555614 November 2021 09:12:00Grand GulfNRC Region 4GE-6A 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 555064 October 2021 19:59:00Arkansas NuclearNRC Region 4CEAt 1433 CDT, on October 4, 2021, Arkansas Nuclear One, Unit 2 (ANO-2) completed the analysis related to an indication revealed on head penetration 46 during Reactor Vessel Closure Head inspections. It was determined the indication is not acceptable under ASME code requirements. The indication displays characteristics consistent with primary water stress corrosion cracking. No leak path signal was identified during ultrasonic testing. The plant was in cold shutdown at 0 percent power and in Mode 6 for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. This is the only indication that is currently present, however, if additional indications are found, they will also be repaired prior to the plant startup. The NRC Senior Resident Inspector has been notified.
ENS 554519 September 2021 04:19:00Grand GulfNRC Region 4GE-6At 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.
ENS 5544331 August 2021 20:52:00WaterfordNRC Region 4CEAt 1340 CDT on August 31, 2021, Waterford 3 Nuclear Generating Station discovered a condition impacting functionality of the ENS and commercial telephone lines. This issue was evaluated and determined to be a major loss of communications capability because the condition affected the ability to directly communicate between the NRC and the Control Room. Satellite phone capability was established at 1410 CDT. Additional communication capability was restored at 1609 CDT. Communication capability via the Emergency Notification System (ENS) was reestablished at 1923 CDT. This condition does not affect the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5543630 August 2021 01:50:00WaterfordNRC Region 4CE

At 1804 CDT on 8/29/2021, Waterford 3 Steam Electric Station (WF3) experienced a Loss of Off Site Power event due to Hurricane Ida (See EN #55435). This event caused an automatic actuation of Emergency Diesel Generators Trains A and B. Both Emergency Diesel Generators started as designed and both are currently operating normally supplying power to their respective Class 1E Safety Busses. This automatic actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). Prior to the loss of offsite power, WF3 was in progress of performing a plant cooldown in accordance with procedural guidance. As part of this cooldown and after entering Mode 4, all Safety Injection Tanks were isolated. As a result of losing offsite power, Reactor Coolant System Temperature increased above 350F which is above the temperature requirements for Mode 4. Safety Injection Tanks are required to be unisolated and OPERABLE in Mode 3. Therefore, with no Safety Injection Tanks OPERABLE, this constituted an event or condition that could have prevented the fulfillment of a safety function and the unit entered Technical Specification 3.0.3. The unit was in Technical Specification 3.0.3 for approximately 43 minutes from 1805 CDT until 1848 CDT when Mode 4 conditions were re-established. This event or condition that could have prevented the fulfillment of a Safety Function is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D). While continuing to perform the Reactor Coolant System Cooldown and prior to placing Shutdown Cooling Train in service, it became necessary to start one train of Emergency Feedwater. Emergency Feedwater Train A was manually started at 1847 CDT to feed the Steam Generators and was secured at 1947 CDT. Emergency Feedwater Train A started and operated normally during this period. This manual actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector.

  • * * UPDATE AT 1549 EDT ON OCTOBER 25, 2021 FROM CHANTEL HATTAWAY TO BRIAN P. SMITH * * *

The purpose of this notification is to revise Event Notification Report (EN) 55436 to include a partial retraction. On August 29, 2021, Waterford Steam Electric Station, Unit 3 (WF3) experienced a loss of offsite power (LOOP) event due to Hurricane Ida. Prior to the LOOP, WF3 had shutdown to Mode 3 (Hot Standby) in anticipation of the LOOP and was performing a plant cooldown in accordance with procedural guidance. When Mode 4 (Hot Shutdown) was achieved, all Safety Injection Tanks (SITs) were isolated as part of the plant cooldown. After the LOOP, Reactor Coolant System (RCS) temperature increased and the Core Exit Thermocouples (CETs) indicated that RCS temperature had exceeded 350 degrees F. Based on the CETs, this was above the temperature requirements for Mode 4 and, as such, WF3 declared entry into Mode 3. The SITs are required to be unisolated and Operable in Mode 3. Since no SITs were Operable at that time, it was determined that this constituted an event or condition that could have prevented the fulfillment of a safety function and included this as part of the EN 55436 report in accordance with 10 CFR 50.72(b)(3)(v)(D). An engineering evaluation has subsequently been performed to validate whether the RCS temperature excursion following the LOOP actually reached 350 degrees F. As defined in WF3 Technical Specification (TS) Table 1.2, Operational Mode temperatures are a function of RCS average temperature (Tavg), not just the indicated temperature of the CETs. Based on the calculated Tavg using validated temperatures, it was concluded that 350 degrees F was not reached. Thus, WF3 remained in Mode 4 following the LOOP and there was no event or condition that could have prevented the fulfillment of a safety function that was reportable pursuant to 10 CFR 50.72(b)(3)(v)(D). The remainder of EN 55436 remains correct and unchanged. The licensee notified the NRC Resident Inspector. Notified R4DO (Pick)

ENS 5543529 August 2021 19:49:00WaterfordNRC Region 4CE

Waterford 3 shut down the reactor in preparation for Hurricane Ida landfall prior to this event. At 1812 CDT, Waterford 3 declared a notification of unusual event under EAL S.U. 1.1 due to a loss of offsite power as a result of hurricane Ida. Plant power is being provided via emergency diesel generators. The NRC Activated at 2016 EDT with Region IV in the lead. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, CISA Central, USDA Ops Center, EPA Emergency Ops Center, DHS Nuclear SSA (email), FEMA NWC (email), and FEMA NRCC SASC (email).

  • * * UPDATE ON 9/1/21 AT 0132 EDT FROM ALEX SANDOVAL TO BRIAN P. SMITH * * *

At 2345 CDT on 8/31/21, Waterford 3 terminated their notification of unusual event under EAL S.U. 1.1. Offsite power has been restored to both safety-related electrical buses. The NRC remains Activated with Region IV in the lead while reviewing additional criteria to exit Activation. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, CISA Central, USDA Ops Center, EPA Emergency Ops Center, DHS Nuclear SSA (email), FEMA NWC (email), and FEMA NRCC SASC (email), R4DO (Josey), IR MOC (Kennedy), NRR EO (Miller), R4 (Lantz).

ENS 5531116 June 2021 23:41:00PalisadesNRC Region 3CEOn June 16, 2021, at 1550 EDT, Palisades Nuclear Plant was operating in Mode 1 at 100% power. At that time, operations identified an acrid odor in the control room. Investigation revealed that the steam dump control relay had failed, rendering all four atmospheric steam dump valves inoperable. The loss of function of all four atmospheric steam dump valves is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D) as an 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 mitigate the consequences of an accident. Troubleshooting and replacement of the relay are in progress. The plant remains stable in Mode 1 at 100% power. The NRC Resident Inspector has been notified. Unit 1 is in a 24 hour LCO for Tech Spec 3.7.4.b, atmospheric steam dump valve inoperability. The Unit is in a normal offsite power line-up.
ENS 5528531 May 2021 10:50:00Arkansas NuclearNRC Region 4CEA licensed operator had a confirmed positive 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 5528128 May 2021 09:04:00WaterfordNRC Region 4CEThis 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Engineered Safety Feature actuation signal. On April 1, 2021, at Waterford 3, while performing a replacement of power supplies on the Plant Protection System, a spurious signal caused a partial actuation of the Emergency Feedwater Actuation Signal. A partial Emergency Feedwater (EFW) logic trip path was met causing the opening of valves EFW-228A (EFW to SG 1 Primary Isolation), EFW-229A (EFW to SG 1 backup isolation), EFW-228B (EFW to SG 2 Primary Isolation), and EFW-229B (EFW to SG2 Backup Isolation). This inadvertent actuation was spurious and was not a valid signal resulting from parameter inputs. The 1992 Statements of Consideration (57 FR 41378) define an invalid signal to include spurious signals. Therefore, this actuation is considered invalid. This event was entered into the Waterford 3 corrective action program for resolution. This event did not result in any adverse impact to the health and safety of the public. The plant responded as expected. In accordance with 10 CFR 50.73(a)(1) a telephone notification is being made in lieu of submitting a written Licensee Event Report. The NRC Senior Resident Inspector has been notified.
ENS 551692 April 2021 14:29:00River BendNRC Region 4GE-6At 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.
ENS 5515425 March 2021 13:37:00River BendNRC Region 4GE-6On 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.
ENS 5513814 March 2021 18:05:00Arkansas NuclearNRC Region 4B&W-L-LPOn March 14, 2021, at 1315 CDT, Arkansas Nuclear One, Unit 1(ANO-1) was manually tripped due to degraded voltage and momentary loss of the A-2, non-vital 4160 V Bus in accordance with Abnormal Operating Procedure. All control rods fully inserted. Degraded voltage of the A-2 non-vital 4160 V Bus resulted in de-energizing the A-4 vital 4160 V Bus. Emergency Diesel Generator No. 2, K-4B, started automatically and is currently powering the A-4 vital 4160 V Bus. All other Vital and Non-Vital Buses transferred power automatically to the Startup Transformer No. 1. Offsite power remains energized and available for ANO-1. All other systems responded as designed. The loss of the A-2 Non-Vital Bus is still under investigation. ANO-1 is currently stable in MODE 3 (Hot Standby), maintaining pressure and temperature with Main Feedwater pumps and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of both 10 CFR 50.72(b)(2)(iv)(B) for the Reactor Protection System actuation and 10 CFR 50.72(b)(3)(iv)(A) for the actuation of the Emergency Diesel Generator. The Licensee has notified the NRC Senior Resident Inspector.
ENS 550989 February 2021 10:35:00CooperNRC Region 4GE-4On February 9, 2021, at 0153 CST, Cooper Nuclear Station experienced a spike in Secondary Containment differential pressure which exceeded the Technical Specifications Surveillance Requirements 3.6.4.1.1 limit of -0.25 inches of water gauge. Secondary Containment differential pressure oscillated coincident with barometric pressure oscillations. Three additional spikes occurred which exceed the Technical Specification limit. The duration of each spike was less than one minute. The last spike occurred at 0232 CST. Secondary Containment differential pressure has restored to Technical Specification limits and further investigation is ongoing. This unplanned Secondary Containment inoperability constitutes a condition reportable under 10CFR50.72(b)(3)(v)(C) and (D), "An event or condition that at the time of discovery could have prevented the fulfillment of the safety function of (Structures, Systems, and Components) SSCs that are needed to control the release of radioactive material and mitigate the consequences of an accident. The NRC Senior Resident Inspector has been informed.
ENS 550567 January 2021 03:18:00Grand GulfNRC Region 4GE-6

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).

  • * * UPDATE ON 01/07/21 AT 0619 EST FROM LEROY PURDY TO BRIAN LIN * * *

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).

ENS 5503011 December 2020 15:15:00Grand GulfNRC Region 4GE-6On 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.
ENS 5502810 December 2020 20:43:00Arkansas NuclearNRC Region 4CE

On December 10, 2020 at 1608 CST, Arkansas Nuclear One, Unit 2 (ANO-2) experienced an automatic reactor scram from 100 percent power due to Low Steam Generator Water Level in 2E-24A Steam Generator. Emergency Feedwater actuated automatically due to low water level in the A Steam Generator. Due to inadequate control of the B Main Feedwater Control System, water level in the B Steam generator rose to a level requiring manual trip of the B Main Feedwater pump. Emergency Feedwater responded as designed to feed both steam generators automatically. All other systems responded as designed. All electrical power is being supplied from offsite power and maintaining unit electrical loads as designed. Unit 2 is currently stable in Mode 3 (Hot Standby) maintaining pressure and temperature via Emergency Feedwater and secondary system steaming. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of both 10 CFR 50.72(b)(2)(iv)(6) for the Reactor Protection System actuation and 10 CFR 50.72(b)(3)(iv)(A) for the actuation of the Emergency Feedwater System. The Arkansas Nuclear One NRC Senior Resident Inspector has been notified.

  • * * UPDATE FROM JOHN LINDSEY TO DONALD NORWOOD AT 1605 EST ON 12/11/2020 * * *

The purpose of this (report) is to provide an update to NRC Event Number 55028. The cause of the inadequate control of the B Main Feedwater Control System to control B Steam Generator Level was verified to be associated with the failure that led to the A Steam Generator low level condition. After taking action to trip the B Main Feedwater Pump, Emergency Feedwater was manually actuated for the B Steam Generator and the Emergency Feedwater System was verified to maintain proper automatic control of both Steam Generator levels. At the time of the initial event notification, plant temperature and pressure control had been transferred from Emergency Feedwater to Auxiliary Feedwater along with secondary system steaming. The licensee notified the NRC Resident Inspector. Notified R4DO (Kellar).

ENS 5501230 November 2020 14:16:00River BendNRC Region 4GE-6A 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.
ENS 5499110 November 2020 22:06:00River BendNRC Region 4GE-6On November 10, 2020, at 1827 CST, River Bend Station (RBS) received a report of a single inadvertent and malfunctioning siren which is part of the Emergency Notification System. The siren was heard by residences in the area and they contacted local agencies, who in turn contacted RBS. This siren activation was not related to any condition or event and no emergency has occurred at RBS. RBS has notified the appropriate authorities and the Governor's Office of Homeland Security and Emergency Preparedness of the inadvertent siren activation. RBS has sent a team to locally disable the siren to prevent any further inadvertent sounding and it is now disabled. A press release from Entergy is not planned at this time. The NRC resident has been notified of the event. The licensee also notified the East and West Feliciana Parish Authorities. If an emergency notification were required, there is overlap of working sirens to cover the area of the siren that is out of service.
ENS 549866 November 2020 05:00:00Grand GulfNRC Region 4GE-6On November 6, 2020, at 0239 CST, Grand Gulf Nuclear Station (GGNS) experienced an Automatic Reactor Scram from 84 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 Resident has been notified.
ENS 549782 November 2020 08:10:00WaterfordNRC Region 4CEOn November 2, 2020, at 0419 CST, Waterford 3 experienced an automatic reactor trip due to a Control Element Drive Mechanism Control System timer failure while attempting to synchronize a second motor generator set. All control rods fully inserted. The plant is currently in Mode 3 and stable with normal feedwater feeding and maintaining both Steam Generators. The NRC Senior Resident Inspector has been notified. The cause of the failure is still under investigation.
ENS 549761 November 2020 09:34:00CooperNRC Region 4GE-4On November 1, 2020, at 0534 CST the reactor was manually scrammed due to an un-isolable leak on the Turbine High Pressure Fluid System. Initial power level when the leak was identified was 100 percent. Power was lowered commencing at 0525 in accordance with shutdown procedures. The Reactor Operator scrammed the reactor at 0534 from approximately 75 percent power. Following the scram, Reactor vessel water level lowered to approximately -20 inches on the Wide Range Instruments, and was subsequently recovered to normal post scram range (approximately 36 inches) using the Reactor Feedwater system. Group 2 Isolation occurred due to Reactor vessel level reaching the isolation setpoint (3 inches). The plant is stable in MODE 3 and proceeding to cold shutdown. The Main Condenser remained available throughout the evolution and condenser vacuum is currently being maintained by the Mechanical Vacuum Pumps. Pressure is being controlled using the steam line drains to the main condenser. All control rods fully inserted and there were no complications. All systems responded as designed. The Turbine High Pressure Fluid System has been secured. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B) due to RPS Actuation-Critical and 50.72(b)(3)(iv)(A) Valid Specified System Actuation. The licensee has notified the NRC Resident Inspector.
ENS 5495419 October 2020 07:20:00Arkansas NuclearNRC Region 4CE
B&W-L-LP

On October 18, 2020 at 2313 CDT, Arkansas Nuclear One (ANO) discovered that 2VRA-1B (2VSF-9 outside air damper reserve bottle) was below 600 psig. This condition caused the control room envelope to be inoperable in accordance with OP-2104.007 Attachment L. ANO Unit 1 entered TS 3.7.9 Condition B for inoperable control room boundary. ANO Unit 2 entered TS 3.7.6.1 Action D for inoperable control room boundary. A procedurally controlled temporary modification was implemented to install a blank flange on the 2VSF-9 outside air damper. Both Units declared the control room boundary operable at 2358 CDT. The associated control room emergency recirculation fan remains inoperable with the blank flange installed. This is a 7-day shutdown-LCO for both units. The licensee informed the NRC Resident Inspector.

  • * * RETRACTION FROM AARON TOSCH TO HOWIE CROUCH ON 10/24/2020 AT 1657 EDT * * *..

Previously, Entergy notified the NRC that ANO control room envelope was inoperable due to 2VRA-1B (2VSF-9 outside air damper reserve bottle) was below required pressure of 600 psig. After additional engineering evaluation, it was determined the control room boundary remained intact for this condition. As documented in version 2 operability determination for condition report ANO-C-2020-2818, the control room ventilation boundary remained intact for the condition identified and was able to fulfill its function for the required 30-day mission time. In accordance with NUREG-1022, 'Event Report Guidelines 10 CFR 50.72 and 50.73,' a report may be retracted based on a revised operability determination. The CRE remained operable; therefore, this report may be retracted. The NRC Resident Inspector has been informed. Notified R4DO (Pick).

ENS 549357 October 2020 10:25:00Grand GulfNRC Region 4A non-licensed employee 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 licensee informed the NRC Resident Inspector.
ENS 5490824 September 2020 06:31:00Grand GulfNRC Region 4On September 24, 2020, at 0258 CDT, Grand Gulf Nuclear Station (GGNS) was notified that one Emergency Notification Siren located on US Hwy 61 had actuated. Claiborne County was informed that no emergency exists at GGNS. The alarming siren has since been secured. Notification is being provided to the NRC in regards to the potential for media inquiry. The licensee informed the NRC Resident Inspector.
ENS 5489711 September 2020 22:54:00PalisadesNRC Region 3At 1930 EDT, on September 11, 2020, Palisades Nuclear Plant was conducting ultrasonic data analysis from reactor vessel closure head in-service inspections. During this analysis, signals that display characteristics consistent with primary water stress corrosion cracking were identified in head penetration 34. No leak path signal was identified during ultrasonic testing. The plant was in cold shutdown at 0% power and in Mode 6 for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. This is the only indication that is currently present, however, if additional indications are found, they will also be repaired prior to the plant startup. The licensee notified the NRC Senior Resident Inspector.
ENS 548804 September 2020 01:40:00River BendNRC Region 4River Bend Station experienced an inadvertent initiation and injection of High Pressure Core Spray (HPCS) at 2048 (CDT) on 9/3/2020 while operating at 92% power. Initial investigation indicates a power supply failure in the Division III trip units which feeds HPCS and Division III Diesel Initiation signals. The Control Room Operator responded to the event by taking manual control of Feedwater Level Control to maintain Reactor Water Level nominal values. The HPCS injection valve was open for approximately 25 seconds before operators manually closed the valve. The manual closure of the injection isolation valve caused the system to be incapable of responding to an automatic actuation signal. The manual override of the injection isolation valve was reset approximately 52 minutes after the event. The HPCS system has remained inoperable. The event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as a condition that caused loss of function of the HPCS System. No radiological releases have occurred due to this event. The Senior NRC Resident Inspector has been notified. These conditions put the unit in a 14-day LCO (3.5.1) for HPCS Inoperability and a 30-day LCO (3.7.1) for one Standby Service Water Pump Inoperable (2C).
ENS 5486731 August 2020 08:28:00PalisadesNRC Region 3A contract employee supervisor had a confirmed positive for alcohol during a fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector.
ENS 5485525 August 2020 02:26:00Grand GulfNRC Region 4On August 24, 2020 at 2305 CT at Grand Gulf Nuclear Station (GGNS) an Automatic Reactor Scram occurred after a trip of the Reactor Feed Pump B and subsequent lowering of reactor water level to 11.4 inches Narrow Range. The scram occurred with Reactor Power at 14% and the main generator offline. All control rods fully inserted and there were no complications. All systems responded as designed. Main Steam Isolation Valves were manually closed to control reactor cooldown, Currently GGNS reactor pressure is being maintained at 450-600psig. Reactor water level is being maintained with condensate through startup level control. No radiological releases have occurred due to this event from the unit. The NRC Resident has been notified. Decay heat is being removed via the main condenser. Notified R4DO.