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 Entered dateSiteRegionReactor typeEvent description
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 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 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 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 5596224 June 2022 16:28:00PerryNRC Region 3GE-6The 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.
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 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 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 5526318 May 2021 09:04:00PerryNRC Region 3GE-6This 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.
ENS 551726 April 2021 04:32:00PerryNRC Region 3GE-6

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.

  • * * RETRACTION ON 5/12/21 AT 1345 EDT FROM JOHN NAKEL TO KERBY SCALES * * *

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).

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 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 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 5500217 November 2020 03:40:00ClintonNRC Region 3GE-6At 1918 CST on 11/16/2020, it was discovered both required trains of the Main Control Room Ventilation and Air Conditioning systems were simultaneously inoperable. Due to these inoperabilities, the systems were in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). Subsequent post-maintenance testing demonstrated that the Division 1 Main Control Room Ventilation system was available at the time of the event and was restored to operable status at 2036 CST on 11/16/2020. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
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 5339912 May 2018 06:58:00Grand GulfNRC Region 4GE-6On 5/11/2018, at 2327 hours CDT, with the plant in Mode 5, Grand Gulf Nuclear Station was making preparations for surveillance test 06-OP-1P75-R-0003, Standby Diesel Generator 1 Functional Test. The Grand Gulf Nuclear Station experienced an auto-start of the Division 1 (Emergency) Diesel Generator (EDG) when the 15AA Bus Potential Transformer (PT) fuse drawer was racked out instead of the line PT fuse drawer for Bus 15AA feeder breaker 152-1514. This resulted in the 15AA Incoming Feeder Breaker 152-1511 from Engineered Safety Features Transformer 12 opening, de-energizing the 15AA Bus. The Division 1 EDG started and energized Bus 15AA. The Division 1 LSS SYSTEM FAIL annunciator was received and Standby Service Water A failed to start due to the 15AA Bus PT fuse drawer being racked out. Standby Gas Treatment Train B was manually initiated per the Loss Of AC Power Off Normal Emergency Procedure. Station equipment operated as expected based on the PT fuse drawer that was racked out. The Division 1 EDG was manually tripped from the Control Room because cooling from the Standby Service Water A was not available. RHR (residual heat removal) B was in Shutdown Cooling (mode) and was verified not affected The licensee has notified the NRC Resident Inspector.
ENS 533824 May 2018 13:50:00River BendNRC Region 4GE-6During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornados, River Bend Station identified non-conforming conditions in the plant design such that specific TS equipment is considered to not be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering the Diesel Generator Building through conduit and pipe penetrations. A tornado could generate multiple missiles capable of striking Division 1, Division 2, and Division 3 Diesel Generator support equipment rendering all Safety Related Diesel Generators inoperable. This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v) for any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (A) Shut down the reactor and maintain it in a safe shutdown condition, (B) Remove residual heat, or (D) Mitigate the consequences of an accident. This condition was identified as part of an on-going extent of condition review of potential tornado missile related site impacts. Enforcement discretion per Enforcement Guidance Memorandum EGM 15-002 has been implemented and required actions taken. Corrective actions will be documented in a follow-on licensee event report. The licensee has notified the NRC Resident Inspector.
ENS 533741 May 2018 20:42:00Grand GulfNRC Region 4GE-6At 1551 hrs (CDT) on 5/1/2018, with the plant in Mode 5, a division one Reactor Pressure Vessel (RPV) Level 1 signal was received; however there was no actual change in RPV level. RPV Level remained at High Water Level supporting refuel operations. This caused an actuation of division one Load Shed and Sequencing system that shed and then re-energized the 15 bus. Division one diesel generator started from standby. Residual Heat Removal pump 'A', which was in shutdown cooling mode, was lost during the bus shed, and was re-sequenced upon re-energization of the 15 bus. Upon restoration of shutdown cooling, the RHR pump discharged into the RPV. RCS temperature increased approximately 5 degrees Fahrenheit as a result of the loss of shutdown cooling. The cause of the actuation signal is under investigation. In accordance with NUREG 1022, Event Reporting Guidelines, this event is conservatively reported under 10 CFR 50.72(b)(2)(iv)(A) as an event that results in emergency core cooling system discharge into the RCS as a result of a valid signal, under 10 CFR 50.72(b)(3)(iv)(B)(8) as an event that results in the actuation of emergency ac electrical power systems, and under 10 CFR 50.72(b)(3)(v)(B) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function (remove residual heat). The licensee notified the NRC Resident Inspector.
ENS 5336526 April 2018 18:50:00River BendNRC Region 4GE-6River Bend Station experienced an inadvertent initiation and injection of High Pressure Core Spray (HPCS) at 1531 (CDT) on 4/26/2018 while operating at 100 percent power. During replacement of Level Transmitter B21-LTN081C 'Reactor Vessel Low Water Level 1', Main Control Room received an inadvertent initiation and injection of High Pressure Core Spray. The HPCS injection valve was open for approximately 40 seconds before the operators manually closed the valve. Feedwater Level Control responded per design and maintained Reactor Water Level nominal values. The Division 3 Diesel Generator (DG) also automatically started in response to the actuation signal. The DG did not automatically connect to the Division 3 switchgear since there was not a low voltage condition on the bus. 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 16 minutes after the event, restoring the system to its standby condition. This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(A) as a condition that caused ECCS (Emergency Core Cooling System) discharge to RCS (Reactor Coolant System) and 10 CFR 50.72(b)(3)(v)(D) as a condition that caused the loss of function of the HPCS System. The Senior NRC Resident inspector has been notified.
ENS 5333513 April 2018 21:04:00Grand GulfNRC Region 4GE-6

At 1208 CDT on April 13, 2018, GGNS (Grand Gulf Nuclear Station) identified cracks in the primary containment concrete penetration (outer wall) around feed water line 'B'. There are no available dimensions for crack width or depth until further inspections are performed. In accordance with NUREG 1022, Event Reporting Guidelines 10 CFR 50.72 and 10 CFR 50.73, Section 3.2.4, any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers being seriously degraded, requires that when a principal safety barrier is declared inoperable the condition must be reported under 10 CFR 50.72 (b)(3)(ii). The licensee has notified the NRC Resident Inspector.

  • * * RETRACTION FROM GERRY ELLIS TO HOWIE CROUCH AT 2012 EDT ON 4/15/18 * * *

Grand Gulf Nuclear Station (GGNS) personnel performed an inspection of the wall around feed water line 'B'. This inspection included the protective coating in the identified area and a partial inspection of the underlying concrete. The inspection of the protective coating found a collection of non-linear anomalies, chipping, and flaking. The inspection found non-significant linear indications in the concrete. Grand Gulf Nuclear Station determined that the collection of non-significant coating imperfections and non-significant indications in the concrete do not constitute serious degradation of primary containment. The indications do not adversely impact the operability, mission time, or safety-function (as described per Technical Specification 3.6.1.1, Primary Containment) of the containment structure. The as-found conditions have been entered into the GGNS corrective action program for final disposition. The containment structure is operable, therefore, GGNS is retracting this event notification. The licensee has notified the NRC Resident Inspector. Notified R4DO (Kellar).

ENS 5332411 April 2018 10:14:00River BendNRC Region 4GE-6At time 0150 CDT on April 11, 2018, a condition was identified that could impair the ability of the Control Building Air Conditioning System to perform its design function. Engineering determined that the time delay relays HVKA11-80YB or HVKA11-80YD (Division II chilled water LOW FLOW relays) could fail in a manner that challenges the design safety function of the Control Building Chilled Water System during a Loss of Offsite Power (LOP) Event. A failure of the time delay relay HVKA11-80YB or HVKA11-80YD (Division II chilled water LOW FLOW relays) to provide the time delay function would cause both the Division I and Division II HVK chilled water pumps to start after a LOP, which in turn could hinder the auto start of either Division I or Division II chillers. Currently the Chilled Water System is otherwise operating as designed. All operator actions are in place to ensure the plant meets all required designed safety system functions. Work is currently underway to correct this design vulnerability. The NRC Resident Inspector has been notified of this condition.
ENS 533175 April 2018 18:23:00Grand GulfNRC Region 4GE-6On Thursday, April 5, 2018, at approximately 1117 hours Central Daylight Time, Entergy contract personnel opened the personnel hatch allowing access to the roof of the Secondary Containment Building for the purposes of performing an inspection of various items located on the roof. During the time period the individuals were on the roof, the hatch was left open. An individual was adjacent to the door with a radio and had constant communication link with the control room operator. Pursuant 10 CFR 50.72(b)(3)(v)(C), and 10 CFR 50.72(b)(3)(v)(D) this event is being reported as an event or condition that could have prevented the fulfillment of a safety function. Because the site had an individual briefed and at the door in constant communications with the control room to close the hatch if condition required such an action, this event is not viewed as an actual loss of safety function. The NRC Resident Inspector was notified.
ENS 5330431 March 2018 10:00:00Grand GulfNRC Region 4GE-6At 0206 (CDT) on March 31, 2018, with the plant in Mode 1 at 100% rated core thermal power, Grand Gulf Nuclear Station experienced a loss of Secondary Containment. During the performance of a Standby Gas Treatment System (SGTS) drawn down test with Auxiliary Building train bay door (1A319A) as the secondary containment boundary, Grand Gulf was unable to maintain secondary containment pressure, as required by SR (surveillance requirement) 3.6.4.1.4, greater than or equal to 0.266 inches of water vacuum for 1 hour. Following initial vacuum draw down, secondary containment pressure degraded to 0.225 inches of water vacuum with operators in the field reporting air leakage from door 1A319A. The test was secured and Secondary Containment was declared inoperable and Technical Specification 3.6.1.4 A.1 was entered. Following completion of the failed surveillance test, Secondary Containment was returned to an operable status at 0315 hours on March 31, 2018, by returning the system to a previously known operable configuration by closing doors 1A310, 1A312 and 1A319. This is being report under 10 CFR 50.72(b)(3)(v)(C). The licensee has notified the NRC Resident Inspector.
ENS 5330330 March 2018 20:47:00ClintonNRC Region 3GE-6On March 30, 2018 at 1305 CDT, with the reactor at 98 percent core thermal power and steady state conditions, plant personnel identified that both doors of the containment personnel airlock were open simultaneously due to failure of the interlock. Personnel were at both the outside and inside doors. Immediate action was taken to close the inner containment personnel airlock door and it was verified closed. Both doors of the containment personnel airlock were open for less than one minute. There was no radioactive release as a result of the event. The cause of the interlock failure is under investigation. This condition requires an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(ii)(A), the condition of the nuclear power plant, including its principal safety barriers (primary containment), being seriously degraded. This condition is also reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material. The NRC Resident Inspector was notified.
ENS 5322723 February 2018 18:04:00Grand GulfNRC Region 4GE-6On February 18, 2018, Grand Gulf Nuclear Station experienced the concurrent inoperability of two Emergency Diesel Generators (DG). This event is being reported as a late 8-hour non-emergency notification per 10 CFR 50.72(b)(3)(v)(D) as an 'Event or Condition that Could Have Prevented Fulfillment of a Safety Function (Accident Mitigation).' On February 14, 2018 at 0100 (CST), the Division 2 Diesel Generator was declared inoperable, and subsequently removed from service for maintenance. On February 18, 2018 at 0006 (CST), the Division 3 Diesel Generator Jacket Water temperature exceeded the trip setpoint and Division 3 Diesel Generator was declared inoperable. The Division 2 Diesel Generator was restored and declared operable on February 18, 2018 at 0355 (CST), and the Division 3 Diesel Generator was restored and declared operable on February 18, 2018 at 1240 (CST). As a result, Technical Specification Condition 3.8.1.E was entered at 0006 (CST) on February 18, 2018 and exited at 0355 (CST) on February 18, 2018. Technical Specification Bases 3.8.1.E.1 states 'With two DGs inoperable, there is one remaining standby AC source. Thus, with an assumed loss of offsite electrical power, insufficient standby AC sources are available to power the minimum required ESF functions.' Offsite power was available throughout this event and there was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5320110 February 2018 22:37:00Grand GulfNRC Region 4GE-6On 2/10/18 at 1835 CST at Grand Gulf Nuclear Station, while the 208 ft. Containment Airlock Outer Door was tagged-out for planned maintenance, the 208 ft. Containment Inner Door was determined to be inoperable. Grand Gulf had performed 06-ME-1M23-R-0001, Personnel Airlock Door Seal Air System Leak Test, on the 208 ft. Containment Airlock Inner Door which had been deemed satisfactory. While performing planned maintenance on the outer door an additional review of the paperwork determined that the test was actually unsatisfactory on the inner door. TS 3.6.1.2 Condition C was entered at 1835 CST on 2/10/18 for both 208 ft. Containment Airlock Doors being inoperable. Maintenance of the Outer Door is expected to be completed, and the airlock returned to operable status, prior to TS required action completion time. The licensee notified the NRC Resident Inspector.
ENS 531921 February 2018 14:23:00River BendNRC Region 4GE-6

At 1057 CST on February 1, 2018 with the unit in Mode 1 at approximately 27% power, a manual actuation of the Reactor Protection System (RPS) was initiated due to an unexpected trip of the B Recirc Pump with A Recirc Pump in fast speed. B Recirc Pump tripped during transfer from slow to fast speed resulting in single loop operation. Operators were unable to reconcile differing indications of core flow. This resulted in a conservative decision to initiate a manual scram. The cause of the B Recirc Pump trip and the apparent issues with core flow indication are under investigation. The plant is currently stable in Mode 3. The plant response to the scram was as expected. All control rods (fully) inserted as expected; the feedwater system is maintaining reactor vessel water level in the normal control band and reactor pressure is being maintained with steam line drains and main turbine bypass valves. The NRC Senior Resident (Inspector) has been notified.

  • * * RETRACTION AT 1015 EDT ON 03/22/2018 FROM DAVID DABADIE TO OSSY FONT * * *

This event was initially reported under 10 CFR 72(b)(2)(iv)(B) as a manual actuation of the RPS due to an unexpected trip of the B Reactor Recirculation Pump with the A Reactor Recirculation Pump running in fast speed (Single Loop Operations). Operations was unable to reconcile differing indications of core flow and made the conservative decision to perform a planned shutdown in accordance with normal operating procedures. Therefore, this event 'resulted from and was part of a pre-planned sequence during testing or reactor operation' as specified in 10 CFR 50.72(b)(2)(iv)(B), 10 CFR 50.73(a)(2)(iv)(A) and NUREG-1022 Section 3.2.6. Consequently, this event is not reportable as an actuation of RPS. The NRC Resident Inspector has been notified. R4DO (Groom) has been notified.

ENS 5318830 January 2018 21:56:00Grand GulfNRC Region 4GE-6On 1/30/2018 at 1750 (CST), the Reactor Pressure Control Malfunctions ONEP (Off Normal Event Procedure) was entered due to main turbine load oscillations of approximately 30 MWe peak to peak. At 1822 (CST), a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown due to continued main turbine load oscillations. Reactor SCRAM ONEP, Turbine Trip ONEP, and EP-2 were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 933 psig using main turbine bypass valves. Reactor Water Level 3 (11.4 inches) was reached which is the setpoint for Group 2 (RHR to Radwaste Isolation) and Group 3 (Shutdown Cooling Isolation). No valve isolated in these systems due to all isolation valves in these groups being in their normally closed position. The lowest Reactor Water level reached was -36 inches wide range. No other safety system actuations occurred and all systems performed as designed. That event is being reported under 10CFR 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 also reported under 10CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS. The MSIVs are open with decay heat being removed via steam to the main condenser using the bypass valves. Off site power is stable, and the plant is in a normal shutdown electrical lineup. RCIC (Reactor Core Isolation Cooling) was out of service for maintenance, and the reactor water level did not reach the system activation level. The cause of the main turbine load oscillations being investigated. The licensee notified the NRC Resident Inspector.
ENS 5313723 December 2017 05:00:00PerryNRC Region 3GE-6High Pressure Core Spray System was declared inoperable due to the discovery of a through-wall leak on the Minimum Flow line. Leak rate is 60 drops per minute from ASME Class 2 Piping. The leak has been isolated and the High Pressure (Core Spray) System has been placed in Secured Status. High Pressure Core Spray is considered a single train safety system. Inoperability of (the) High Pressure Core Spray System is considered 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. This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D). The NRC Senior Resident Inspector was notified. Technical Specifications Limiting Condition for Operation 3.5.1 Condition B was entered, requiring restoration of the High Pressure Core Spray System in 14 days. The licensee plans to notify State and Local Governments (Lake, Geauga, and Ashtabula Counties).
ENS 5311712 December 2017 20:34:00Grand GulfNRC Region 4GE-6At approximately 1330 CST on Tuesday, December 12, 2017, Grand Gulf Nuclear Station declared Division 3 'C' Battery inoperable due to questions concerning battery terminal connection continuity. Technical Specification 3.8.4, DC Sources - Operating, Condition E, Required Action E.1, requires the station to declare the High Pressure Core Spray System inoperable immediately. The Division 3 'C' Battery and High Pressure Core Spray System was declared operable and the LCOs (Limiting condition of operation) were declared met at 1731CST on Tuesday, December 12, 2017. Based on field measurements of terminal torque and resistance, the as-found and as-left terminal resistance micro-ohm readings indicated satisfactorily all times. Formal evaluation of the as-found condition of the battery is in progress. This report is to notify the NRC of a loss of safety function on the High Pressure Core Spray System. The NRC Resident Inspector was notified.
ENS 5311512 December 2017 17:40:00Grand GulfNRC Region 4GE-6At approximately 0918 CST on Tuesday, December 12, 2017, the Grand Gulf Nuclear Station experienced a loss of the Engineered Safety Features (ESF) Transformer 11 which was powering the Division 1 ESF bus. Subsequently, the station experienced an automatic start of the Division 1 Emergency Diesel Generator (EDG), partial isolation of the primary and secondary containment buildings and the isolation of the Reactor Core Isolation Cooling System (RCIC). It is not currently understood why the RCIC system isolated during this event. A team is investigating this issue separately from the loss of the ESF 11 transformer. The cause of the event is under investigation at this time. No other issues or unexpected events occurred. The NRC Resident Inspector has been notified of the event.
ENS 531109 December 2017 18:42:00ClintonNRC Region 3GE-6

At approximately 1347 (CST) on 12/09/17, the Main Control Room received annunciators that indicated a trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1 breaker. Numerous Division 1 components lost power (powered from unit subs 1A and A1). The Division 1 containment Instrument Air isolation valves had failed closed by design due to the loss of power. Due to the loss of containment instrument air, several control rods began to drift into the core as expected and, by procedure, the reactor mode switch was placed in the shutdown position at 1353 (CST). All control rods fully inserted. Also due to the loss of power, the Fuel Building ventilation dampers failed closed by design. With the normal ventilation system secured, secondary containment differential pressure rose to slightly greater than 0 inches water gauge which exceeded the Technical Specification requirement of greater than 0.25 inches vacuum water gauge at 1348 (CST). The Control Room entered EOP-8, Secondary Containment Control. Secondary Containment differential pressure was restored within Technical Specification requirements at 1351 (CST) by starting the Division 2 Standby Gas Treatment system. This event is being reported as a manual actuation of the Reactor Protection System (RPS) and as a Condition that Could Have Prevented Fulfillment of a Safety Function.

The cause is currently under investigation. The NRC Resident has been notified. The licensee informed the NRC Resident Inspector.

  • * * UPDATE FROM DALE SHELTON TO VINCE KLCO AT 1658 EST ON 12/10/2017 * * *

During a review of plant logs it was identified that the primary to secondary containment differential pressure was identified to be outside of Technical Specification 3.6.1.4 limits of 0 plus or minus 0.25 psid at 2009 on 12/9/17 due to the primary containment ventilation system dampers closing as a result of the loss of power. This parameter is an initial safety analysis assumption to ensure that primary containment pressures remain within the design values during a Loss of Coolant Accident (LOCA). As a result, this condition is reportable as an unanalyzed condition that significantly degrades plant safety. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone).

  • * * UPDATE FROM MICHAEL ANTONELLI TO VINCE KLCO ON 12/11/17 AT 1805 EST * * *

During the post transient review of the trip of the 4160 V 1A1 breaker 1AP07EJ, 480V XFMR 1A and A1, it was identified that the unplanned INOPERABILITY of the Low Pressure Core Spray (LPCS) system due to the loss of power to the injection valve constitutes an event or condition that could have prevented fulfillment of a safety function and is reportable under 10CFR50.72(b)(3)(v)(D) for Accident Mitigation. The High Pressure Core Spray (HPCS) remained available to perform the core spray function, if necessary, during a design basis Loss of Coolant Accident (LOCA), however HPCS and LPCS are each considered single train safety systems. The NRC Senior Resident Inspector has been notified. Notified the R3DO (Stone).

ENS 5309025 November 2017 06:02:00Grand GulfNRC Region 4GE-6

At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 (CST), with reactor power just above the point of adding heat, IRM (Intermediate Range Monitor) channels A, C, and D received a spurious upscale trip signal which immediately cleared. Upon investigation, operability of RPS (Reactor Protection System) scram function for Intermediate Range Detectors was placed in question. 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. The licensee notified the NRC Resident Inspector.

  • * * UPDATE ON NOVEMBER 26, 2017, AT 1850 FROM GRAND GULF TO MICHAEL BLOODGOOD * * *

At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. At 0149 (CST), with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event is being reported under 10CFR 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. This Revised Statement to Event Notification # 53090 is being made to make it clear that only four IRM channels (A, C, D, G) were Inoperable and that the IRM RPS SCRAM function was still available from the four remaining Operable IRM channels (B, E, F, and H). The licensee notified the NRC Resident Inspector. Notified R4DO (O'Keefe)

  • * * RETRACTION ON 01/16/2018 AT 1629 EST FROM JASON COMFORT TO DAVID AIRD * * *

On 11/25/17, at 0149 (CST), with reactor power just above the point of adding heat, Intermediate Range Monitor neutron flux detector (IRM) channels A, C, and D received a spurious Upscale Trip signal which immediately cleared. Upon investigation, IRM channels A, C, and D were declared Inoperable. IRM G was already Inoperable for another reason. At 0238 (CST) a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown. RPS scram function from IRM channels B, E, F, and H was always Operable and available. That event was initially 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. After the trip alarms were received, the Operators spent approximately twenty minutes investigating possible causes and implications, and consulted with Reactor Engineering and the Shift Technical Advisor. The investigation showed that the plant was stable and the upscale IRM alarms were spurious. A review of plant technical specifications by the operators determined that a plant shutdown was not required. After further discussions, Operations concluded that a shutdown to allow further investigation of the issue was the prudent course of action. Prior to shutting down, Operations spent approximately twenty minutes reviewing procedures, notifying personnel to exit containment, and conducting a brief. The shutdown was then conducted by inserting a manual reactor scram by placing the reactor mode switch in SHUTDOWN. This was initially reported under 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the RPS. Based on the sequence of events, and Operator actions in conducting the shutdown, the event is considered 'part of a pre-planned sequence during testing or reactor operation' as specified in 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.73(a)(2)(iv)(A). In accordance with NUREG-1022, Section 3.2.6, the event is not reportable as an actuation of RPS. The licensee notified the NRC Resident Inspector. Notified R4DO (Taylor).

ENS 530545 November 2017 17:11:00ClintonNRC Region 3GE-6At approximately 1240 CST on 11/05/17, the Main Control Room received numerous annunciators that indicated a trip of the Emergency Reserve Auxiliary Transformer (ERAT) Static VAR (volt-ampere reactive) Compensator (SVC) caused by a voltage transient on the 138 kV feed due to thunderstorms in the area. As a result of the voltage transient, the Division 1 Fuel Building ventilation (VF) system isolation dampers closed causing a trip of VF supply and exhaust fans. With no running VF fans, secondary containment differential pressure rose to slightly greater than 0 inches water gauge which exceeded the Technical Specification requirement of greater than 0.25 inches vacuum water gauge at 1241. The Control Room entered EOP-8, Secondary Containment Control. This event is being reported as a Condition that Could Have Prevented Fulfillment of a Safety Function under 10CFR50.72(b)(3)(v)(C). Secondary Containment differential pressure was restored within Technical Specification requirements at 1242 by starting the Standby Gas Treatment HVAC (VG) system. The NRC Resident Inspector has been notified.
ENS 5303826 October 2017 18:18:00Grand GulfNRC Region 4GE-6

At 1055 (CDT), drywell purge supply/initial vacuum relief 1E61F003B was declared INOPERABLE for Drywell Vacuum Relief System while performing a monthly surveillance. 1E61F003B is a Division II powered valve. Division 1 Emergency Diesel Generator is INOPERABLE due to a tagout. At 1455, under LCO 3.8.1.B.2 the station declared both divisions of Drywell Vacuum Relief INOPERABLE. GGNS (Grand Gulf Nuclear Station) identified that a loss of Safety Function occurred due to a loss of two 10-inch vacuum relief lines from the Drywell required by Technical Specification 3.6.5.6 and therefore could have prevented fulfillment of its safety function. That event is being reported under 10CFR50.72(b)(3)(v)(D), as any event or condition that, at the time of discovery, could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Both divisions inoperable has placed the plant in a 72-hr. LCO shutdown action statement. The licensee has notified the NRC Resident Inspector.

  • * * RETRACTION FROM RALPH FLICKINGER TO HOWIE CROUCH AT 1643 EST ON 12/15/17 * * *

At 1055 (CDT on 10/26/17), Drywell purge supply/initial vacuum relief 1E61F003B was declared INOPERABLE for Drywell Vacuum Relief System while performing a monthly surveillance. 1E61F003B is a Division II powered valve. Division 1 Emergency Diesel Generator was INOPERABLE due to a tagout. At 1455 (CDT on 12/26/17), under LCO 3.8.1.B.2, the station declared both divisions of Drywell Vacuum Relief INOPERABLE. GGNS identified that a loss of Safety Function occurred due to a loss of two 10-inch vacuum relief lines from the Drywell required by Technical Specification 3.6.5.6 and therefore could have prevented fulfillment of its safety function. This was initially reported under 10 CFR 50.72(b)(2)(v)(D). Div. 1 EDG was initially taken out of service at 1455 on 10/26 for preplanned maintenance (OP-EVAL). It was subsequently declared INOPERABLE-INOP due to a visible flaw indication in the exhaust manifold (1117 on 10/27). A subsequent Maintenance Functional Failure Evaluation and Past Operability Determination concluded the diesel was capable of performing its intended function for the required mission time, and therefore met the definition of OPERABLE. NUREG-1022 provides clarification for 10 CFR 50.72(b)(2)(v). NUREG Section 3.2.7, paragraph 4, states '...unless a condition is discovered that would have resulted in the system (otherwise) being declared inoperable, reports are not required when systems are declared inoperable solely as a result of Required Actions for which the bases is the assumption of an additional random single failure (i.e., . ..LCO 3.8.1, 'AC Sources Operating,' Required Actions .., B.2, or C.1). Per ACTION 3.8.1 .B.2, both trains of Drywell vacuum and Drywell Purge were inoperable for the purposes of Tech Specs. However, the normal power supply was available to Division 1 and there were no conditions which would have rendered the Division 1 diesel inoperable. Therefore, per Section 3.2.7 of NUREG-1022, this was not a Loss of Safety Function and was not reportable under 50.72(b)(2)(v)(D). The licensee has notified the NRC Resident Inspector. Notified R4DO (Deese).

ENS 530004 October 2017 05:53:00PerryNRC Region 3GE-6

On October 4, 2017, at 0250 hours (EDT), the Perry Nuclear Power Plant commenced a Technical Specification (TS) shutdown by lowering reactor power from 100 percent rated thermal power to 98 percent to comply with TS LCO 3.0.3. Reactor power was further reduced to 82 percent rated thermal power at 0430 hours (EDT). The plant had entered TS 3.0.3 at 0155 hours (EDT) upon loss of MCC (Motor Control Center), Switchgear, and Miscellaneous Electrical Equipment Areas HVAC System train A while train B was removed from service for maintenance. MCC switchgear ventilation train A was declared inoperable based on excessive belt noise and a dropped belt on MCC switchgear supply fan A. This also constitutes a loss of safety function. This event is being reported in accordance with 10 CFR 50.72(b)(2)(i) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified.

  • * * UPDATE ON 10/04/17 AT 0926 EDT FROM DAN HARTIGAN TO STEVEN VITTO * * *

Due to the loss of both trains of MCC, Switchgear, and Miscellaneous Electrical Equipment Areas HVAC, actions were taken in LCO 3.8.7 for AC and DC Distribution Systems, LCO 3.8.4 for DC Sources, LCO 3.8.1 for AC Sources, and the associated support systems, the High Pressure Core Spray system was also declared inoperable, which is a single train safety system and therefore, an additional loss of safety function. This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(B), 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72 (b)(3)(v)(D). At 0620 hours (EDT) the A train of MCC, Switchgear, and Miscellaneous Electrical Equipment Areas HVAC and High Pressure Core Spray was declared operable and LCO 3.0.3 was exited. The plant was restored to 100% (percent) power at 0804 (EDT). The NRC Resident Inspector was notified. Notified R3DO(Hills).

ENS 5299527 September 2017 14:26:00River BendNRC Region 4GE-6Security personnel reported to the Main Control Room that at time 1000 CDT (on 9/27/2017), an alarm indicated that a secondary containment door was open beyond the normal delay time allowed for entry and exit. Security personnel responded and found the door open and unattended with the dogs extended meaning that the door was unable to be closed. Security personnel secured the door at time 1004 CDT. No deficiencies were found with the door. The fact the door was open and unattended beyond the time allowed for normal entry and exit results in Technical Specification 3.6.4.1 'Secondary Containment-Operating,' not being met because surveillance requirement SR 3.6.4.1.3 is not met. This surveillance requires that doors be closed except during normal entry and exit. By definition in NUREG-1022, when Secondary Containment is inoperable, it is not capable of performing its specified safety function which in turn makes this condition reportable in accordance with 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified.
ENS 5293629 August 2017 14:42:00Grand GulfNRC Region 4GE-6

On August 22, 2017 at 2321 hours, Grand Gulf Nuclear Station entered Technical Specification conditions for three Limiting Condition for Operations (LCOs) not met due to Residual Heat Removal 'A' (RHR 'A') being declared inoperable. LCOs not met:

  1) 3.5.1 for one low pressure ECCS (Emergency Core Cooling System) injection/spray subsystem.
  2) 3.6.1.7 for one RHR containment spray subsystem, and
  3) 3.6.2.3 for one RHR suppression pool cooling subsystem.

The station has made the decision to shutdown the plant based on the results of troubleshooting performed on the RHR 'A' pump. The restoration of RHR 'A' pump will not be completed prior to the end of the 7 day LCO completion time. Grand Gulf Nuclear Station initiated plant shutdown required by Technical Specifications 3.5.1, 3.6.1.7, and 3.6.2.3 at 1200 hours CDT on 08/29/2017 due to expected restoration of RHR 'A' exceeding the completion time of 7 days prior to restoring operability. The licensee notified the NRC Resident Inspector.

ENS 5292123 August 2017 10:51:00Grand GulfNRC Region 4GE-6

At approximately 0340 CDT on Wednesday, August 23, 2017, Grand Gulf Nuclear Station was notified by the Entergy System Dispatcher that the NRC had called them and told them that the NRC could not contact Grand Gulf on the Emergency Notification System (ENS) line nor commercial telephone. Control Room personnel immediately tested several offsite lines including the NRC ENS line and found the lines were non-functional. Offsite prompt Public Warning Sirens were available at all times. State and Local notification capability was available via UHF radio communication. GGN Emergency Response Organization notification capability was available at all times via satellite phone activation of group paging. GGN site Emergency Response Facility intercommunications were available at all times via site internal telephones. In-plant and offsite team communications were available at all times via UHF radio. This event is being reported (8-hour notification) as an event or condition that adversely impacted offsite communications in accordance with 10 CFR 50.72(b)(3)(xiii), specifically the loss of the NRC Emergency Notification System (ENS). The phone company has been contacted and actions are being taken to restore normal communications capability at this time. The NRC Resident Inspector has been notified.

  • * * UPDATE AT 1701 EDT ON 08/23/17 FROM LEROY PURDY TO JEFF HERRERA * * *

At 1701 EDT on 8/23/17 the phone systems at Grand Gulf have been restored. The licensee will be notifying the NRC Resident Inspector. Notified the R4DO (Farnholtz)

ENS 5291518 August 2017 23:41:00River BendNRC Region 4GE-6At 2055 CDT on August 18, 2017, an automatic actuation of the reactor protection system occurred while the plant was operating at 100 percent power. No plant parameters requiring the actuation of the emergency diesel generators or the emergency core cooling system were exceeded. The main feedwater system remained in service following the scram to maintain reactor water level, and the main condenser remained available as the normal heat sink. The scram occurred after a planned swap of the main feedwater master controller channels in preparation for scheduled surveillance testing. When the channel swap was actuated, the feedwater regulating valves moved to the fully open position. The scram signal originated in the high-flux detection function of the average power range monitors, apparently from the rapid increase in feedwater flow. The cause of the apparent feedwater controller malfunction is under investigation. The NRC Resident Inspector has been notified. No safety relief valves opened. Decay heat is being removed via steam to the main condenser using the bypass valves and steam drains. The licensee intends to go to Cold Shutdown to investigate the malfunction.
ENS 5290815 August 2017 20:21:00River BendNRC Region 4GE-6A blind sample provided from an independent laboratory to fleet testing facility was returned with inaccurate results. This is in violation of 10 CFR 26.719(c)(3) and requires a 24-hour report. The licensee has notified the NRC Resident Inspector.
ENS 5290315 August 2017 04:58:00PerryNRC Region 3GE-6On August 14th, 2017 at 2257 (EDT), while shutting down the Annulus Exhaust Gas Treatment System (AEGTS) Train B, secondary containment pressure momentarily lowered. This resulted in the Technical Specification (TS) for Secondary Containment to not be met for 15 seconds. The minimum Secondary Containment vacuum observed during that time was 0.52 inch of vacuum water gauge. Secondary Containment pressure was returned to within the TS operability limit of 0.66 inch of vacuum water gauge (TS SR 3.6.4.1.1) by the AEGTS Train A that remained in operation. There were no radiological releases associated with this event. Declaring Secondary Containment inoperable is reportable under (10 CFR) 50.72(b)(3)(v)(C) & (D) for an event or condition that could have prevented the fulfillment of a safety function of a system that is needed to:(C) Control the release of radioactive material; or (D) Mitigate the consequences of an accident. The licensee has notified the NRC Resident Inspector.
ENS 5289710 August 2017 17:14:00River BendNRC Region 4GE-6A non licensed supervisor confirmed positive for alcohol during a fitness for duty test. The employee's access has been terminated. The NRC Resident Inspector has been notified.
ENS 528918 August 2017 20:22:00PerryNRC Region 3GE-6On August 8, 2017, at 1554 hours (EDT), during restoration from testing of the High Pressure Core Spray (HPCS) Suppression Pool Level High Instrumentation, unexpected as-left indications were found that impacted both of the required channels of instrumentation. Subsequent venting of the instrumentation lines was completed and both channels of instrumentation are reading consistent with previously taken as-found data. The instrumentation was declared OPERABLE at 1635. The initial cause of the unexpected as-left indications appears to be the introduction of air into the instrumentation lines during the calibration activities. This is considered a loss of safety function based on both of the HPCS Suppression Pool Level High Instrumentation channels being declared INOPERABLE and the loss of the automatic HPCS suction swap to the Suppression Pool on a high level. This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D). The (NRC Resident Inspector) has been notified.