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 Entered dateSiteRegionReactor typeEvent description
ENS 5406212 May 2019 15:28:00Grand GulfNRC Region 4

At 1039 CDT the reactor was manually (scrammed) due to a partial loss of plant service water. The loss of plant service water was caused by a loss of (balance of plant) BOP transformer 23. Reactor power was reduced in an attempt to restore pressure to plant service water. Reactor level is being maintained with condensate and feedwater. Reactor pressure is being maintained with bypass control valves. Standby Service Water A and B were manually initiated to supply cooling to Control Room A/C and (Engineered Safety Feature) ESF switchgear room coolers. The cause is under investigation. The NRC Resident Inspector has been notified. 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 also reported under 10 CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS and Standby Service Water. The plant is currently in a normal electrical lineup.

  • * * UPDATE ON 5/12/19 AT 1846 EDT FROM GERRY ELLIS TO JEFFREY WHITED * * *

This is an update to the original notification. The Drywell and Containment exceeded the technical specification (TS) temperature limits of 135 degrees F (TS Limiting Condition of Operation (LCO) 3.6.5.5) and 95 degrees F (TS LCO 3.6.1.5), respectively. An 8-hour notification is being added 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 control the release of radioactive material per 10 CFR 50.72(b)(3)(v)(C). Notified R4DO (Alexander).

ENS 5389423 February 2019 19:05:00Grand GulfNRC Region 4Actuation of RPS (Reactor Protection System) with the reactor critical. Reactor scram occurred at 1458 (CST) on 2/23/2019 from 100% power. The cause of the scram was due to Turbine Control Valve Fast Closure. All control rods are fully inserted. Currently reactor water level is being maintained by the Condensate Feedwater System in normal band and reactor pressure is being controlled via Main Turbine Bypass valves to the main condenser. No ECCS (Emergency Core Cooling System) initiation signals were reached and no ECCS or Diesel Generator initiation occurred. The Low-Low Set function of the Safety Relief Valves actuated upon turbine trip. This was reset when pressure was established on main turbine bypass valves. The cause of the turbine trip is still under investigation. There were no complications with scram response. The licensee notified the NRC Resident Inspector. There was no maintenance occurring on the main turbine at the time of the scram.
ENS 5387013 February 2019 09:42:00Grand GulfNRC Region 4On 1/17/2019 at 0619 CST, a non-licensed employee supervisor failed to report to perform a fitness for duty test. The individual's access to the site was terminated. The NRC Resident Inspector will be notified.
ENS 5378812 December 2018 17:29:00Grand GulfNRC Region 4

EN Revision Text: MANUAL REACTOR SCRAM DUE TO FAILED OPEN TURBINE BYPASS VALVE At 1351 CST, the reactor was manually shutdown due to 'A' Turbine Bypass Valve opening. The Main Steam Line Isolation Valves were manually closed to facilitate reactor pressure control. Reactor level is being maintained through the use of Reactor Core Isolation Cooling System, Control Rod Drive System, and High Pressure Core Spray System. High Pressure Core Spray System was manually started to initially support reactor water level control. Reactor Pressure is being controlled through the use of the Safety Relief Valves and the Reactor Core Isolation Cooling System. The plant is stable in MODE 3. The cause of the 'A' Turbine Bypass Valve opening is under investigation at this time. The NRC Resident Inspector has been notified.

  • * * UPDATE ON 12/14/18 AT 1140 EST FROM GERRY ELLIS TO TOM KENDZIA * * *

This is an update to EN # 53788 to correct an error on the event classification block of the form. The original notification did not have the block for 8 hour notification for Specified System Actuation checked. The actuation of Reactor Core Isolation Cooling System was discussed in original notification. The licensee notified the NRC Resident Inspector. Notified R4DO (Taylor).

ENS 5360814 September 2018 21:09:00Grand GulfNRC Region 4At 1644 (CDT) a manual reactor scram was inserted by placing the Reactor Mode Switch to Shutdown. At 1643 (CDT) the Condensate Booster Pump A tripped on low suction pressure. At 1644 (CDT) the Reactor Feed Pump A tripped on low suction pressure. A Recirculation Flow Control Valve runback occurred as designed. Reactor Water level was approaching the Automatic Low Water Level 3 (11.4 inches) scram set point and manual actions were taken by placing the Mode Switch to Shutdown before the low level set point was reached. All systems responded as expected following the manual scram. The plant is stable in mode 3. This 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. The NRC Senior Resident Inspector has been notified. All control rods fully inserted, and decay heat is being removed through the turbine bypass valves to the main condenser. The licensee is investigating the cause of the event.
ENS 5356627 August 2018 13:15:00Grand GulfNRC Region 4On 27 August 2018 at 0918 CDT Grand Gulf Control Room was informed that the onsite credit union silent alarm was actuated. The credit union is located outside of the Secure Owner Controlled Area (SOCA), but is located within the Owner Controlled Area. GGNS (Grand Gulf Nuclear Station) Security entered an elevated security position at 0920 (CDT) and requested assistance from local law enforcement. Claiborne County Sheriff's Department responded to the site. Investigation of the area conducted with the assistance of GGNS Security personnel determined that the cause of the notification was not valid. GGNS Security stood down from the elevated security positon at 0945 (CDT). Pursuant to 10 CFR 50.72(b)(2)(xi), this issue is being reported as any event or situation, related to the health and safety of the public or on-site personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made."
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 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 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 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 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 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 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 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 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 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 5284310 July 2017 05:42:00Grand GulfNRC Region 4GE-6At 2158 (CDT) a door to the Control Room Envelope was left unsecure. GGNS (Grand Gulf Nuclear Station) identified that a loss of Safety Function occurred due to a breach in the Control Room Envelope resulting in inoperability of both divisions of Standby Fresh Air and therefore could have prevented fulfillment of its safety function. The Control Room Envelope was inoperable for one minute. This event is being reported under 10CFR 50.72(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. The licensee notified the NRC Resident Inspector.
ENS 526634 April 2017 06:57:00Grand GulfNRC Region 4GE-6At 0010 (CDT), 04/04/2017, the reactor was manually scrammed from approximately 75 (percent) core thermal power due Condensate Storage tank level lowering to 24 feet. All control rods fully inserted and all systems actuated and operated as designed. No safety relief valves actuated. Reactor level and pressure are currently being controlled within normal bands. RCIC (reactor core isolation cooling) was manually initiated for level control. This event is reportable under 10CFR50.72(b)(2)(iv)(B) for the reactor trip and 50.72(b)(3)(iv)(A) for the manual start of the reactor core isolation cooling system. The cause of lowering level was a condensate pipe leak. Decay heat is being removed via steam dumps to the condenser. The electrical grid is stable and supplying plant loads. The licensee has notified the NRC Resident Inspector.
ENS 5251627 January 2017 23:05:00Grand GulfNRC Region 4GE-6This notification is to report a loss of safety function in accordance with 10 CFR 50.72(b)(3)(v)(D). At approximately 1808 CST hours on Friday, January 27, 2017, the Grand Gulf Nuclear Station Unit 1 High Pressure Core Spray (HPCS) system was declared inoperable due to the trip of the HPCS Jockey Pump. At the time of discovery, Unit 1 was in Mode 2 and raising power in the source range to return to power operations. No other safety systems were inoperable at the time of this event. Investigation into the cause of the event is ongoing and the system will be returned to operational status prior to proceeding to Mode 1. The licensee has notified the NRC Resident Inspector.
ENS 522258 September 2016 04:27:00Grand GulfNRC Region 4GE-6On September 4, 2016 at 0258 (CDT), Grand Gulf Nuclear Station entered three (Technical Specification) Limiting Conditions for Operations (LCOs) due to residual heat removal pump 'A' (RHR 'A') being declared inoperable. LCOs entered: 1) 3.5.1 for one low pressure ECCS 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. Station management has made the decision to shutdown the plant to repair the RHR 'A' pump prior to the end of the 7 day LCO completion time based on troubleshooting and testing performed on the RHR 'A' pump. Grand Gulf Nuclear Station initiated plant shutdown required by Tech Spec Actions 3.5.1, 3.6.1.7, and 3.6.2.3, at 0300 CDT on 09/08/2016 due to expected inability to restore RHR 'A' to operable status prior to exceeding the LCO time of 7 days. The unit is currently at 82 percent power. There are no other systems out of service that would complicate the orderly shutdown to Mode 4. The licensee will notify the NRC Resident Inspector.
ENS 5205730 June 2016 22:54:00Grand GulfNRC Region 4GE-6On June 30, 2016 at 1715 CDT, Grand Gulf Nuclear Station (GGNS) experienced an electrical power supply loss from Service Transformer 21 which resulted in power supply being lost to Division 2 (16AB Bus) and Division 3 (17AC Bus) ESF buses. This resulted in a valid actuation of Division 2 and Division 3 Diesel Generators on bus under voltage. They both automatically started and energized their respective ESF buses as designed. During this event, the loss of power to the Division 2 (16AB Bus) resulted in a Division 2 RPS bus power loss, which actuated a Div 2 RPS half SCRAM signal. The power loss also resulted in a loss of the Instrument Air pressure resulting in some Control Rod Scram Valves to drift open. This in turn caused the Scram Discharge Volume to fill to the point where a Div 1 RPS half SCRAM signal was initiated from Scram Discharge Volume level high on Channel 'A'. This resulted in a valid full RPS Reactor SCRAM while not critical. Instrument Air pressure was restored and the SCRAM signal was reset at 1733 CDT. Appropriate off normal event procedures were entered to mitigate the transient. No ECCS initiation signals were reached. All safety systems performed as expected. GGNS was in Mode 4, Cold Shutdown, with MSIVs closed at the time of the event. Reactor water level was maintained in the normal water level band by Control Rod Drive system throughout this event. RHR 'A' was maintained in Shutdown Cooling operation and it was not affected by this event. The licensee notified the NRC Resident Inspector.
ENS 5204425 June 2016 18:30:00Grand GulfNRC Region 4GE-6At 1407 (CDT), during power ascension to 100 percent, turbine control valves closed unexpectedly causing reactor protection trip signals that in turn caused a reactor scram. Reactor scram, turbine trip ONEPs (Off Normal Event Procedure), and EP2 (Emergency Procedure for Level Control) were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 935 psig using bypass valves. No other safety system actuations occurred and all systems performed as designed. All control rods inserted. Reactor level is maintained by feedwater. Normal electrical shutdown configuration is through offsite electrical power sources. The Safety Relief Valves lifted, then closed. The plant is stable at normal level and pressure and remains in Mode 3. The event is under licensee investigation. The licensee notified the NRC Resident Inspector.
ENS 5201217 June 2016 06:21:00Grand GulfNRC Region 4GE-6During planned stop and control valve testing, two main turbine high pressure stop valves closed instead of the expected one (stop valve 'B'). This caused the main turbine control valves, power, reactor pressure to swing and a division 2 half SCRAM. Control rods were inserted to reduce power and the power swings. At 0257 (CDT) the reactor automatically SCRAMMED. Reactor SCRAM, Turbine Trip (procedures) ONEPs and EP-2 were entered. Reactor water level was stabilized at 34 inches narrow range on startup level control and reactor pressure stabilized at 884 psig using main turbine bypass valves. No other safety related systems actuated and all systems performed as expected. The plant is in its normal shutdown electrical lineup using normal feedwater and turbine bypass valves for decay heat removal. Reactor pressure is slowly trending down. The licensee is investigating the cause of the second stop valve shutting. The licensee notified the NRC Resident Inspector.
ENS 5182729 March 2016 14:06:00Grand GulfNRC Region 4GE-6A Reactor Scram occurred at 1123 CDT on 03/29/2016 from 35% CTP (core thermal power). The cause of the Scram appears to be a Turbine Generator trip. The station's procedures, '05-S-01-EP-2 RPV (Reactor Pressure Vessel) Control, 05-1-02-I-1 Reactor Scram ONEP (Off Normal Event Procedure) and 05-1-02-l-2 Turbine Generator Trip ONEP,' were entered to mitigate the transient with all systems responding as designed. No loss of offsite or ESF (engineered safety feature) power occurred. No ECCS (emergency core cooling systems) initiation signals were reached and no ESF or Diesel Generator initiations occurred. All control rods fully inserted. MSIVs (main steam isolation valves) remained open, no SRVs (safety relief valves) lifted, and no containment isolation signals were generated. Currently, reactor water level is being maintained by the Condensate and Feedwater System in normal band and reactor pressure and temperature are being maintained by the Reactor Water Cleanup System. The main condenser is available. There are no challenges to Primary or Secondary Containment at this time. The licensee has notified the NRC Resident Inspector.
ENS 5180017 March 2016 23:15:00Grand GulfNRC Region 4GE-6At 1515 (CDT) on March 17th 2016, Grand Gulf Nuclear Station received a valid actuation signal of the Division 2 Engineered Safety Feature (ESF) Load Shedding and Sequencing system. The actuation signal was most likely caused by a lightning strike to the offsite power source supplying this ESF bus. This caused a loss of the in service shutdown cooling system and associated system actuations. Grand Gulf Nuclear Station (GGNS) was in Mode 5 at 85 (degrees) F coolant temperature. Reactor Cavity was flooded to High Water Level with a time to reach 200 (degrees) F of 7.5hrs. GGNS is conducting a planned refuel outage with core alterations in progress. Systems were aligned as follows: Division 2 Diesel Generator was OPERABLE and the associated ESF bus aligned to transformer ESF12 (115KV Port Gibson offsite feeder). Residual Heat Removal (RHR) system 'B' was in service in shutdown cooling being supplied from this ESF bus (16AB) with Alternate Decay Heat Removal available as a backup. Division 3 Diesel Generator was unavailable due to planned maintenance on support systems. The associated ESF bus was also aligned to transformer ESF12 (115KV Port Gibson offsite feeder). Division 1 Diesel Generator was available and the associated ESF bus aligned to the transformer ESF 11 (Switchyard offsite power feeders Baxter-Wilson and Franklin). Power was never lost to this bus. RHR 'A' and Low Pressure Core Spray (LPCS) were not available due to planned maintenance (tagged out of service). ESF 21 Transformer was out of service for planned maintenance. A suspected lightning strike caused a momentary perturbation in power in the 115KV Port Gibson line causing the Division 2 Load Shedding and Sequencing (LSS) system to actuate. This actuation caused a loss of Residual Heat Removal system 'B' due to being shed (expected). The Division 2 Diesel Generator started and tied onto the bus as expected, restoring power in 7 seconds. Shutdown cooling was restored at 1518 (CDT) and was out of service for 3 mins 13 sec. Reactor coolant and spent fuel pool temperatures remained at 85 (degrees) F throughout this scenario. Core Alterations were suspended and fuel placed in its designated location per the approved movement plan. Division 3 systems; High Pressure Core Spray, Standby Service Water System 'C', and Division 3 Diesel Generator were tagged out of service for planned maintenance. Division 3 Diesel Generator received a valid actuation signal but did not start due to being out of service. The Division 3 bus was restored manually to ESF 11. All safety systems operated as expected for the loss of power to ESF 12 and Division 2 LSS actuation. This is being reported under: 1. 10CFR50.72(b)(3)(iv)(A)-Specified system actuation; Division 2 LSS and Division 3 Diesel Generator start logic. 2. 10CFR50.72(b)(3)(v)(B)-RHR Capability; Loss of shutdown cooling. The NRC Resident Inspector has been notified.
ENS 5176027 February 2016 09:20:00Grand GulfNRC Region 4GE-6A contract employee supervisor had a confirmed positive for alcohol during follow up FFD testing. The employee's access to all Entergy plants has been terminated. The licensee has notified the NRC Resident Inspector.
ENS 5154918 November 2015 18:30:00Grand GulfNRC Region 4GE-6An 8 oz. can of alcohol 'Mike's Harder Lemonade' (8% by volume) was discovered inside the protected area. The can was unopened. Site security took possession of the can and removed it from the protected area. This report is being made under 10CFR26.719(b)(1) as a 24 hour telephone notification. The licensee notified the NRC Resident Inspector.
ENS 5147315 October 2015 22:02:00Grand GulfNRC Region 4GE-6At 1220 CDT on October 14, 2015, GGNS identified that in June 2013, testing of two containment isolation valves in a penetration were not tested in accordance with Technical Specification Surveillance Requirement 3.6.1.3.9. Specifically, the pressure used to demonstrate operability of the penetration did not meet the post-Extended Power Uprate expected highest Containment pressure during an accident. The valves were declared inoperable and isolated in accordance with Technical Specification 3.6.1.3, Primary Containment Isolation Valves (PCIVs) . Even though a reasonable assurance that the safety function could be met existed based on previous analysis and testing, the containment penetration was declared inoperable until appropriate testing could be completed to demonstrate operability. Testing of the penetration was completed at 1101 CDT on October 15, 2015 and demonstrated that both penetration valves were operable at the higher test pressure for the entire time period between June 2013 and October 15, 2015. In accordance with NUREG-1022, Event Reporting Guidelines 10 CFR 50.72 and 50.73, Section 3.2.7, Event or Condition that Could Have Prevented Fulfillment of a Safety Function, requires that when a signal train system is declared inoperable the condition must be reported under 10CFR 50.72(b)(3)(v)(C). The licensee notified the NRC Resident Inspector.
ENS 514597 October 2015 22:47:00Grand GulfNRC Region 4GE-6

At 1930 (CDT) on 10-7-2015, GGNS (Grand Gulf Nuclear Station) identified that on October 1, 2015, Secondary Containment was inoperable between 0324 and 0440 and therefore could have prevented fulfillment of its safety function. That event is being reported under 10 CFR 50.72(b)(3)(v)(c), 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 control the release of radioactive material. During the Standby Gas Treatment drawdown surveillance performed October 1, 2015, Secondary Containment failed technical specification required average enclosure building pressure of less than or equal to -0.311 water gauge at 0324 (CDT) (LCO-1-TS-15-0360 entered). Secondary Containment has two boundaries that can be separately credited for meeting the Tech Spec requirements of TS 3.6.4.1. Two inner doors are required to be open during the surveillance in order to test the outer door. While open, those inner doors were attended by Security personnel provided with communications capability.

Following completion of the surveillance, Secondary Containment was returned to operable status at 0440 on 10/1/15 by closing the inner doors and maintaining them closed. A subsequent Standby Gas Treatment drawdown surveillance test on October 6, 2015, was performed satisfactorily. The NRC Resident Inspector was notified.

ENS 514576 October 2015 17:56:00Grand GulfNRC Region 4GE-6At 1333 (CDT) on 10-6-2015, GGNS (Grand Gulf Nuclear Station) was notified by Claiborne County Civil Defense that the Public Notification System (ANS) Sirens in Claiborne County had been inadvertently initiated by Claiborne County at 1330 today. In response, GGNS informed Claiborne County, MS, State of Mississippi, Tensas Parish, LA, the State of Louisiana and other government agencies of a spurious actuation of the emergency response sirens in Claiborne County. The duration of the siren actuation was approximately 2 minutes. Upon cancellation of the siren activation command at 1332, the Claiborne County Emergency Director issued a 'NO EMERGENCY' message via CODE RED and Tone Alert Radio. At approximately 1342, Claiborne County Emergency Management Agency also faxed a 'NO EMERGENCY' Emergency Alert System message transmission request to the following television stations: WJMI, WLBT, and WJTV. The licensee stated Claiborne County technicians believed this was caused by human error. The Licensee notified the NRC Resident Inspector.
ENS 5132114 August 2015 18:09:00Grand GulfNRC Region 4GE-6

On August 14, 2015, the Grand Gulf Nuclear Station (GGNS) determined that less than 75% of the population in the ten mile EPZ could have been notified using the alert notification system (sirens). This condition existed between the time period starting sometime after 1800 (CDT) on Friday, July 31, 2015 until 1630 (CDT) on Monday August 3, 2015. The completion of this notification was delayed because at the time of discovery the available information and built in system redundancy supported a conclusion that greater than 75% of the population could have been notified using the siren system. The diversity of the systems required repairs and testing to be coordinated with local officials in both Mississippi and Louisiana. At 1000 CDT hours on August 3, 2015, GGNS was informed that the Claiborne County Emergency Operations Center (EOC) siren activation equipment had lost power over the weekend. Investigations and repairs were initiated by Claiborne County Emergency management upon discovery. The system was repaired and functional at 1630 hours on August 3, 2015. The licensee reported that 30 of 42 sirens lost power. The NRC Resident Inspector has been notified.

  • * * UPDATE FROM DAVID BURRUS TO JOHN SHOEMAKER AT 1243 EDT ON 9/23/15 * * *

Based on a detailed investigation (an apparent cause evaluation performed by the Grand Gulf Nuclear Station) into the events surrounding the power interruption at the Claiborne County EOC, Entergy has determined that the emergency power source for the Claiborne County EOC was available and would have been manually established by the Claiborne County EOC Emergency Director if the facility was activated. Upon discovery of the problem, maintenance was immediately performed on the system to reestablish the normal source of power to the Claiborne County EOC. This maintenance required approximately 8 hours to complete. This maintenance activity required the lock-out tag-out of all power (normal and back-up) to the facility. During the time period that all power was removed from the facility, the pre-established and pre-approved back-up notification system was available and would have been utilized to complete the required public notifications. Supplement 1 to Revision 3 of NUREG-1022, Event Reporting Guidelines, 10CFR50.72(b)(3)(xiii), states in part the following: NEI 13-01 proposes that for extended unplanned losses of the primary public alerting system, a report would not be required if the FEMA approved backup alerting method was available and the primary public alerting system was returned to service within 24 hours This 24-hour cap is put into place to limit reliance on a less capable backup alerting method. However, because some backup capability exists, NRC action or awareness is not likely warranted in such scenarios for which the loss of the primary capability is limited in duration. As a result, a report would not be required Therefore, Entergy is updating the above notification based on the developed information that the Claiborne County EOC Emergency Director understood how and would have manually established electrical power to the alert notification system if required and because the maintenance period was less than the 24 hour allowable period established in Supplement 1 to Revision 3 of NUREG-1022. The licensee has notified the NRC Resident Inspector. Notified R4DO (Pick).

ENS 511378 June 2015 00:45:00Grand GulfNRC Region 4GE-6

At 2359 EDT on June 7, 2015, the Grand Gulf Nuclear Station declared a Notice of Unusual Event in accordance with Emergency Action Level HU4 for a fire in the protected area lasting greater than 15 minutes. The fire started in the wiring of a terminal box for Electro Hydraulic Pump C, the running pump located in the turbine building. The running pump was then deenergized by operators and the standby pump started. The site fire brigade responded and extinguished the fire. The emergency was terminated at 0030 on June 8, 2015. The licensee notified state and local agencies and will inform the NRC Resident Inspector. Notified DHS SWO, FEMA Ops Center, NICC Watch Officer, and FEMA NWC and Nuclear SSA via email.

  • * * RETRACTION AT 1645 ON 7/9/2015 FROM KEITH HUFF TO MARK ABRAMOVITZ * * *

The notification of an Unusual Event is being retracted because the event did not meet the definition of 'fire' in NEI 99-01 Revision 5, 'Methodology of the Development of Emergency Action Levels'. The document was endorsed by the NRC on February 22, 2008 (see ADAMS ascension # ML080450149) and is part of the Grand Gulf Nuclear Station's current licensing basis. Per the guidance, a 'fire' is defined as: 'Combustion characterized by heat and light. Sources of smoke such as slipping drive belts or overheated electrical equipment do not constitute as 'fires'. Observation of flame is preferred but is NOT required if large quantities of smoke and heat are observed.' According to eyewitness reports from personnel, flames were not observed at any time and evidence of large quantities of heat and smoke were not observed. Additionally, the definition of 'fire' specifically excludes overheated electrical equipment. This information leads to the conclusion that the event did not meet the definition of a 'fire' per NEI 99-01 Revision 5. Therefore, the event is not an immediately reportable Unusual Event under 10 CFR 50.72(a)(1)(i). The licensee notified the NRC Resident Inspector and will notify the state and local governments. Notified the R4DO (Haire) and NRR EO (Morris via e-mail).

ENS 507957 February 2015 21:47:00Grand GulfNRC Region 4GE-6A reactor SCRAM occurred at 1856 CST on 2/7/15 from 100 percent core thermal power. The cause of the SCRAM appears to be a Generator/Turbine trip, but it is still under investigation. Appropriate off-normal event procedures were entered to mitigate the transient with all systems responding as designed. No loss of offsite or ESF power occurred. No ECCS initiation signals were reached, and no ECCS or Emergency Diesel Generator initiations occurred. Main Steam Isolation Valves remained open and Safety Relief Valves lifted and reseated as designed. Currently, reactor water level is being maintained by the Condensate and Feedwater system in normal band, and reactor pressure is being controlled via turbine bypass valves to the main condenser. Following the reactor SCRAM, all rods fully inserted and all systems functioned as expected. The plant is in a normal electrical lineup. The licensee has notified the NRC Resident Inspector.
ENS 507864 February 2015 17:57:00Grand GulfNRC Region 4GE-6

At 0934 CST hours on Wednesday, February 4, 2015 during a housekeeping inspection, an inspection port (18x18 inch opening) on the Control Room Fresh Air (CRFA) System was discovered open. The opening of the inspection port resulted in the loss of safety function for both trains of CRFA as a loss of control room envelope boundary. The cause of the inspection port being open is currently unknown and is under investigation. The Control Room was notified and an operator immediately secured the inspection port returning both trains of CRFA to operable status. The reactor was at approximately 100 percent power at the time of the discovery of the event. The Limiting Condition for Operation (LCO) Technical Specification 3.7.3, Control Room Fresh Air (CRFA) System, is two CRFA subsystems shall be OPERABLE. This Technical Specification is applicable in MODES 1, 2, and 3, and during operations with a potential for draining the reactor vessel. This condition is reportable as an 8 hour call in accordance with 10 CFR 50.72(b)(3)(v). The licensee has notified the NRC Resident Inspector.

  • * * RETRACTION AT 1520 EST ON 02/13/15 FROM PAUL SALGADO TO S. SANDIN * * *

Grand Gulf Nuclear Station is retracting this event notification based on the following: Regulatory Guidance in NUREG-1022, Revision 3, Event Reporting Guidelines 10 CFR 50.72 and 50.73, Sections 2.8 Retraction and Cancellation of Event Reporting and 4.2.3 ENS Notification Retraction. Once the inspection port was discovered open, the control room was notified and an operator immediately secured the inspection port. After the port was secured, detailed engineering calculations were initiated to analyze the situation. Due to the time needed to perform the detailed calculations versus the time required for notification (8 hours) a conservative decision was made to report the event based on knowledge at the time of the event and rough calculations. Subsequently detailed calculations were performed to evaluate and support system operability evaluation. The calculations evaluated dose sensitivity analysis for the increased Control Room in-leakage due to the open inspection port. A test determined the control building in-leakage to be 585 cfm, the in-leakage from other sources to be 15 cfm, and the calculation determined the flow rate through the opening to be 1245 cfm. This total in-leakage rate of 1845 cfm is below the maximum allowable control building in-leakage of 2000 cfm. The calculation performed a sensitivity analysis with recent ILRT results applied and concluded that 4200 cfm in-leakage is permissible to maintain within the limits of 10CFR50.67. By subtracting the measured in-leakage assuming all ports closed ( 585+15= 600 cfm) from the in-leakage permissible to maintain within the limits of 10CFR50.67 (4200 cfm), there Is a resulting margin of 3600 cfm. Technical Specification 3.7.3, Control Room Fresh Air (CRFA) System, requires TWO CRFA subsystems shall be OPERABLE, and the calculations show that the CFRA was OPERABLE. The calculations lead to the conclusion that the system would have fulfilled its safety function needed to mitigate the consequences of an accident. Therefore, this event is not an 8-hour notification under 50.72(b)(3)(v). The licensee informed the NRC Resident Inspector. Notified R4DO (Allen).

ENS 5056123 October 2014 16:11:00Grand GulfNRC Region 4GE-6A non-licensed employee supervisor had a confirmed positive result for alcohol during a for cause fitness-for-duty test. The employee's access to the plant has been suspended. The licensee has informed the NRC Resident Inspector.
ENS 4997229 March 2014 14:09:00Grand GulfNRC Region 4GE-6Actuation of RPS with reactor critical. Reactor Scram occurred at 1008 (CDT) on 03/29/2014 from 87% CTP (core thermal power). The cause of the Scram appears to be a Turbine Generator Trip. 05-S-01-EP-2 RPV Control, 05-1-02-I-1 Reactor Scram ONEP and 05-1-02-l-2 Turbine Generator Trip ONEP were entered to mitigate the transient with all systems responding as designed. No loss of offsite or ESF (engineered safety feature) power occurred. No ECCS (emergency core cooling systems) initiation signals were reached and no ESF or Diesel Generator initiations occurred. All control rods are fully inserted. MSIVs (main steam isolation valve) remained open and no SRVs (safety relief valves) lifted. Currently, reactor water level is being maintained by the Condensate and Feedwater system in normal band and reactor pressure is being controlled via Main Turbine Bypass Valves to the main condenser. There are no challenges to Primary or Secondary Containment at this time. The licensee has notified the NRC Resident Inspector.
ENS 4992017 March 2014 09:25:00Grand GulfNRC Region 4GE-6On 3/17/2014 at 0514 (CDT) the reactor was manually scrammed from approximately 41% core thermal power due to a steam leak in the turbine building. All control rods fully inserted and all systems actuated and operated as designed. All Main Steam Isolation Valves were manually shut. The Reactor Core Isolation Cooling System was manually initiated to assist in level control and pressure control. No safety relief valves actuated automatically. Manual cycling of safety relief valves and Reactor Core Isolation Cooling are being used to maintain reactor water level and pressure within normal bands. Group 2 and 3 RHR isolation signals were received; however no valve movement occurred since the affected valves are normally closed. This event is reportable under 10CFR50.72(b)(2)(iv)(B) for the reactor trip and 50.72(b)(3)(iv)(A) for the manual start of the reactor core isolation cooling system. The licensee informed the NRC Resident Inspector.
ENS 4989411 March 2014 11:57:00Grand GulfNRC Region 4GE-6This is a 4-hour notification to report a Notification to the State of Mississippi is being made in accordance with the Response to Contaminated Spills/Leaks procedure. A surface contamination event has occurred at the Grand Gulf Nuclear Station that meets the State reporting criteria of 'An unmonitored and inadvertent contaminated leak or spill greater than 15 cubic feet-solid to the environment occurs.' The source of the contamination is not known at this time, investigation to determine the source and extent of the event is in progress. The known contamination has been contained. Actions include sampling of storm drains to verify no unmonitored release outside the protected area, additional radiation protection monitoring of the area, removal of the contaminated liquid and soil, and covering of the affected ground. Installation of tenting over the area is in progress. There was no effect on plant operation. No one was injured during the event. The licensee has notified the NRC Resident Inspector, State, and local governments.
ENS 4964717 December 2013 22:13:00Grand GulfNRC Region 4GE-6During performance of 06-IC-1E31-Q-1016-02 RCIC Steam Supply Pressure Low, the RCIC Containment Isolation Valve 1E51F063, RCIC STM SPLY DRWL INBD ISOL, closed. The procedure for this surveillance (which had recently been revised) should have directed the opening of the breakers for isolation valves 1E51F063 and 1E51F076, RCIC STM LINE WARMUP VLV, which are the division two inboard containment isolation valves for the RCIC system. The procedure incorrectly directed the breakers to be opened for the 1E51F064, RCIC STM SPLY DRWL OTBD ISOL, and 1E51F076. The 1E51F076 is a division two valve and the 1E51F064 is a division one valve. Both the 1E51F076 and 1E51F064 were open at the time their breakers were opened, which resulted in the loss of isolation capability for this containment penetration. The NRC Resident Inspector has been notified.
ENS 4962511 December 2013 15:56:00Grand GulfNRC Region 4GE-6A licensed employee had a confirmed positive test for illegal drugs during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector.
ENS 4922530 July 2013 17:32:00Grand GulfNRC Region 4GE-6

Actuation of Reactor Protection System with reactor critical. Reactor Scram occurred at 1432 CDT on 7/30/2013 from 100% Power. The cause of the scram appears to be a Turbine Generator trip. 05-S-01-EP-2, 'Reactor Pressure Vessel Control,' 05-1-02-I-1, 'Reactor Scram Off Normal Event Procedure,' and 05-1-02-I-2, 'Turbine and Generator Trip Off Normal Event Procedure,' were entered to mitigate the transient. No Loss of Off-site Power occurred. No Emergency Core Cooling System or Diesel Generator initiation occurred. Reactor Core Isolation Cooling initiated and injected. The lowest reactor water level reached was -36 inches wide range (RCIC initiation set point is -41.6 inches wide range). Main Steam Isolation Valves remained open and no Safety Relief Valves actuated. Currently, Main Turbine Bypass valves are controlling reactor pressure to the Main Condenser and Condensate and Feedwater is controlling reactor water level in the normal band and removing decay heat. There are no challenges to Primary or Secondary Containment. The NRC Senior Resident Inspector was notified.

* * * UPDATE FROM CHRIS ROBINSON TO PETE SNYDER AT 1841 EDT ON 7/30/13 * * * 

The first out recorder indicated that RPS actuation signal was due to high reactor pressure as a result of the turbine control valves going shut. Notified R4DO (Farnholtz).

ENS 4921022 July 2013 23:14:00Grand GulfNRC Region 4GE-6A licensed employee had a confirmed positive test for illegal drugs during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector.
ENS 4913619 June 2013 15:30:00Grand GulfNRC Region 4GE-6

At 1410 CDT, Grand Gulf declared an Unusual Event for EAL H.U.5, release of toxic and flammable gases adverse to normal operation of the plant. CO2 was discharged in the electrical switchgear room in the auxiliary building. No injuries or fatalities were found after an initial search of the area. The cause of the CO2 discharge is under investigation. The NRC Resident Inspector was notified. Notified DHS SWO, FEMA, DHS NICC, and Nuclear SSA via email.

  • * * UPDATE ON 1748 EDT AT 6/19/2013 FROM RUSSELL BURDITT TO DONG PARK * * *

All areas of the auxiliary building have been verified to have no oxygen deficiency." The Unusual Event was terminated at 1628 CDT. The NRC Resident Inspector was notified. Notified R4DO (Walker), NRR EO (Giitter), and IRD (Marshall). Notified DHS SWO, FEMA, DHS NICC, and Nuclear SSA via email.

ENS 4903014 May 2013 18:22:00Grand GulfNRC Region 4GE-6A licensed operator had a confirmed positive for alcohol during a for cause fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector.
ENS 4902512 May 2013 19:15:00Grand GulfNRC Region 4GE-6

At 1743 CDT on 05/12/13, Grand Gulf Nuclear Station declared an Unusual Event due to a fire lasting greater than 15 minutes in an auxiliary transformer inside the Protected Area (PA). The transformer was isolated. The plant continues to operate at 100% power. The license remains in a Unusual Event pending further investigation. The licensee notified the NRC Resident Inspector and State and Local Authorities. Notified DHS SWO, FEMA, and DHS NICC.

  • * * UPDATE FROM ROBERT BRINKMAN TO JOHN SHOEMAKER AT 2112 EDT ON 5/12/13 * * *

The Licensee terminated the Unusual Event at 1921 CDT on 5/12/13 based on electrically isolating the auxiliary transformer and termination of smoke coming from the transformer. At no time were flames seen during this event. The transformer is located outside of the turbine building and is used to supply various loads and office space during outages. There was no other impact on the plant. The licensee notified the NRC Resident Inspector and State and Local Authorities. Notified R4DO (Drake), NRR EO (Bahadur), IRD (Marshall), DHS SWO, FEMA, and DHS NICC.

  • * * RETRACTION FROM CHRISTOPHER ROBINSON TO JOHN SHOEMAKER AT 1057 EDT ON 5/29/13 * * *

EN #49025 documents an emergency declaration of Notification of Unusual Event due to a fire lasting greater than 15 minutes within the protected area. The basis for retraction is that this event did not meet the definition of FIRE in NEI 99-01 Rev 5, 'Methodology for the Development of Emergency Action Levels'. This document was endorsed by the NRC on February 22, 2008 (see ADAMS ascension # ML080450149) and is part of the Grand Gulf Nuclear Station's current licensing basis. Per the guidance, a FIRE is defined as: Combustion characterized by heat and light. Sources of smoke such as slipping drive belts or overheated electrical equipment do not constitute FIRES. Observation of flame is preferred but is NOT required if large quantities of smoke and heat are observed. Grand Gulf performed interviews of operators and personnel responding to the event and subsequently examined photos of the affected auxiliary transformer. According to eyewitness reports from personnel, flames were not observed at any time nor was there any light emanating from the source of smoke. Personnel also reported that at the immediate vicinity of the smoke source, heat was not at a level which would be indicative of a fire. Photos of the affected transformer did not show signs of charring, burns, warping, or deformation as would be expected during a FIRE. Additionally, the definition of a FIRE specifically excludes overheated electrical equipment. Notified R4DO (Azua), NRR EO (Chernoff), and IRD (Morris).

ENS 4897326 April 2013 12:25:00Grand GulfNRC Region 4GE-6A licensed operator had a confirmed positive test for illegal drugs during a random fitness-for-duty test. The licensed operator's plant access has been terminated. The licensee notified the NRC Resident Inspector