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| Entered date | Site | Region | Reactor type | Event description | |
|---|---|---|---|---|---|
| ENS 56727 | 7 September 2023 23:35:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | The following information was provided by the licensee via email: On September 7 at 1230 CDT, Arkansas Nuclear One personnel identified 5 bottles of vanilla extract in kitchen areas located inside the Protected Area. A total of 5 bottles were identified. The bottles ranged in sizes of 1 to 4 ounces. Ingredients were listed as vanilla extracts in water and alcohol. The percentage by volume of alcohol varied from 13 - 41 percent. This report satisfied the reporting criteria of 10 CFR 26.719. The NRC Resident Inspector has been notified. |
| ENS 56351 | 14 February 2023 14:40:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | The following information was provided by the licensee via email: On February 14, 2023 at 1103 CST, Arkansas Nuclear One, Unit 1, (ANO-1) automatically tripped on reactor protection system actuation due to two reactor coolant pumps tripping. ANO-1 is currently stable in MODE 3 (Hot Standby) maintaining reactor coolant system pressure and temperature with main feedwater and steaming to the condenser. No additional safety system actuations occurred. All immediate actions were completed satisfactorily. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) for the reactor protection system actuation. The NRC Senior Resident Inspector has been notified. Unit 2 was not affected. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee is investigating the cause of the two reactor coolant pump trips. |
| ENS 56140 | 4 October 2022 15:54:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | A non-licensed supervisor had a confirmed positive during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. |
| ENS 56136 | 1 October 2022 00:08:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | A supplemental supervisor violated the station's FFD policy. The individuals access to the plant has been terminated. The licensee notified the NRC Senior Resident Inspector. |
| ENS 55614 | 29 November 2021 18:47:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | On November 29, 2021 at 1458 CST, Arkansas Nuclear One, Unit 1, (ANO-1) automatically tripped due to high Reactor Coolant System pressure after the 'A' Main Feedwater Pump was manually tripped due to lowering speed. ANO-1 is currently stable in MODE 3 (Hot Standby) maintaining pressure and temperature with the P-75 Auxiliary Feedwater pump and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) for the Reactor Protection System actuation. The NRC Senior Resident Inspector has been notified. Unit 2 was not affected. |
| ENS 55506 | 4 October 2021 19:59:00 | Arkansas Nuclear | NRC Region 4 | CE | At 1433 CDT, on October 4, 2021, Arkansas Nuclear One, Unit 2 (ANO-2) completed the analysis related to an indication revealed on head penetration 46 during Reactor Vessel Closure Head inspections. It was determined the indication is not acceptable under ASME code requirements. The indication displays characteristics consistent with primary water stress corrosion cracking. No leak path signal was identified during ultrasonic testing. The plant was in cold shutdown at 0 percent power and in Mode 6 for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. This is the only indication that is currently present, however, if additional indications are found, they will also be repaired prior to the plant startup. The NRC Senior Resident Inspector has been notified. |
| ENS 55285 | 31 May 2021 10:50:00 | Arkansas Nuclear | NRC Region 4 | CE | A licensed operator had a confirmed positive during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. |
| ENS 55138 | 14 March 2021 18:05:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | On March 14, 2021, at 1315 CDT, Arkansas Nuclear One, Unit 1(ANO-1) was manually tripped due to degraded voltage and momentary loss of the A-2, non-vital 4160 V Bus in accordance with Abnormal Operating Procedure. All control rods fully inserted. Degraded voltage of the A-2 non-vital 4160 V Bus resulted in de-energizing the A-4 vital 4160 V Bus. Emergency Diesel Generator No. 2, K-4B, started automatically and is currently powering the A-4 vital 4160 V Bus. All other Vital and Non-Vital Buses transferred power automatically to the Startup Transformer No. 1. Offsite power remains energized and available for ANO-1. All other systems responded as designed. The loss of the A-2 Non-Vital Bus is still under investigation. ANO-1 is currently stable in MODE 3 (Hot Standby), maintaining pressure and temperature with Main Feedwater pumps and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of both 10 CFR 50.72(b)(2)(iv)(B) for the Reactor Protection System actuation and 10 CFR 50.72(b)(3)(iv)(A) for the actuation of the Emergency Diesel Generator. The Licensee has notified the NRC Senior Resident Inspector. |
| ENS 55028 | 10 December 2020 20:43:00 | Arkansas Nuclear | NRC Region 4 | CE | On December 10, 2020 at 1608 CST, Arkansas Nuclear One, Unit 2 (ANO-2) experienced an automatic reactor scram from 100 percent power due to Low Steam Generator Water Level in 2E-24A Steam Generator. Emergency Feedwater actuated automatically due to low water level in the A Steam Generator. Due to inadequate control of the B Main Feedwater Control System, water level in the B Steam generator rose to a level requiring manual trip of the B Main Feedwater pump. Emergency Feedwater responded as designed to feed both steam generators automatically. All other systems responded as designed. All electrical power is being supplied from offsite power and maintaining unit electrical loads as designed. Unit 2 is currently stable in Mode 3 (Hot Standby) maintaining pressure and temperature via Emergency Feedwater and secondary system steaming. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of both 10 CFR 50.72(b)(2)(iv)(6) for the Reactor Protection System actuation and 10 CFR 50.72(b)(3)(iv)(A) for the actuation of the Emergency Feedwater System. The Arkansas Nuclear One NRC Senior Resident Inspector has been notified.
The purpose of this (report) is to provide an update to NRC Event Number 55028. The cause of the inadequate control of the B Main Feedwater Control System to control B Steam Generator Level was verified to be associated with the failure that led to the A Steam Generator low level condition. After taking action to trip the B Main Feedwater Pump, Emergency Feedwater was manually actuated for the B Steam Generator and the Emergency Feedwater System was verified to maintain proper automatic control of both Steam Generator levels. At the time of the initial event notification, plant temperature and pressure control had been transferred from Emergency Feedwater to Auxiliary Feedwater along with secondary system steaming. The licensee notified the NRC Resident Inspector. Notified R4DO (Kellar). |
| ENS 54954 | 19 October 2020 07:20:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | On October 18, 2020 at 2313 CDT, Arkansas Nuclear One (ANO) discovered that 2VRA-1B (2VSF-9 outside air damper reserve bottle) was below 600 psig. This condition caused the control room envelope to be inoperable in accordance with OP-2104.007 Attachment L. ANO Unit 1 entered TS 3.7.9 Condition B for inoperable control room boundary. ANO Unit 2 entered TS 3.7.6.1 Action D for inoperable control room boundary. A procedurally controlled temporary modification was implemented to install a blank flange on the 2VSF-9 outside air damper. Both Units declared the control room boundary operable at 2358 CDT. The associated control room emergency recirculation fan remains inoperable with the blank flange installed. This is a 7-day shutdown-LCO for both units. The licensee informed the NRC Resident Inspector.
Previously, Entergy notified the NRC that ANO control room envelope was inoperable due to 2VRA-1B (2VSF-9 outside air damper reserve bottle) was below required pressure of 600 psig. After additional engineering evaluation, it was determined the control room boundary remained intact for this condition. As documented in version 2 operability determination for condition report ANO-C-2020-2818, the control room ventilation boundary remained intact for the condition identified and was able to fulfill its function for the required 30-day mission time. In accordance with NUREG-1022, 'Event Report Guidelines 10 CFR 50.72 and 50.73,' a report may be retracted based on a revised operability determination. The CRE remained operable; therefore, this report may be retracted. The NRC Resident Inspector has been informed. Notified R4DO (Pick). |
| ENS 54339 | 20 October 2019 19:21:00 | Arkansas Nuclear | NRC Region 4 | At 1030 CDT, it was discovered that the loop seal on the condensate drain was empty for VUC-9 Control Room AC Unit. This creates a breach in the Control Room envelope. Unit 2 entered (Technical Specification) T.S. 3.7.6.1 Action D. Unit 1 is in Mode 6; therefore, not in a mode of applicability. Compensatory action were being performed and the licensee was in the process of sealing the loop. The licensee will notify the NRC Resident Inspector.
This report is being retracted. The Control Room Envelope (CRE) provides a safety function which limits radiological dose to occupants to no more than 5 rem for 30 days post-accident. The dose limitation assumes the occupants are stationed within the CRE 24 hours a day for the entire 30-day period. The CRE also functions to protect occupants from potential hazards such as smoke or toxic chemicals. The CRE is declared inoperable when a potential breach is identified, regardless of the ability to seal the breach. With respect to the event of October 20, 2019, the water level in a loop seal could not be maintained at the desired level. Subsequent evaluation determined that sufficient water was maintained in the loop seal to prevent a breach of the CRE. The subject reporting criterion is based on the assumption that safety-related systems, structures, and components (SSCs) may no longer be capable of mitigating the consequences of an accident. In accordance with NUREG 1022, 'Event Report Guidelines 10 CFR 50.72 and 50.73,' a report may be retracted based on a revised operability determination. The CRE remained operable; therefore, this report may be retracted. The licensee notified the NRC Resident Inspector. Notified R4DO (Young). | |
| ENS 54312 | 5 October 2019 16:29:00 | Arkansas Nuclear | NRC Region 4 | At 0850 CDT, on 10/5/2019, the control room was notified of a personnel injury in the Unit 1 containment building. The individual was considered potentially contaminated since a complete frisk could not be performed prior to transport to a local hospital. At 1234 CDT, a radiological survey determined that the individual and their clothing had trace amounts of activity that was easily removed. The employee did not sustain any life threatening injuries. This is reportable under 10 CFR 50.72(b)(3)(xii). Additionally, at 1135 CDT contact was made with the Arkansas Department of Health about transport of the potentially contaminated individual. This is reportable under 10 CFR 50.72(b)(2)(xi) due to notification of an offsite agency. The NRC Resident Inspector has been notified. | |
| ENS 54152 | 8 July 2019 18:40:00 | Arkansas Nuclear | NRC Region 4 | A non-licensed contract supervisor had a confirmed positive for a controlled substance 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 54147 | 3 July 2019 18:32:00 | Arkansas Nuclear | NRC Region 4 | This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Engineered Safety Feature actuation signal. On May 9, 2019, at Arkansas Nuclear One (ANO) Unit 1, while performing an Emergency Feedwater Initiation and Control (EFIC) Channel B monthly test, a test pushbutton was mispositioned, resulting in an inadvertent initiation of the Emergency Feedwater (EFW) System. In accordance with the Engineered Safeguards Actuation System (ESAS) Trip Test portion of the surveillance, the first technician placed EFIC Train B in the tripped condition. The second technician then went to the front of the control room to verify Remote Switch Matrix (RSM) indications. The first technician recalls thinking he was given the order to reset Train B EFW Bus 1 Trip. Therefore, the first technician performed the step using three-part communication, but there is uncertainty about what was said. Due to the amount of time the second technician spent in front of the control room, the first technician assumed Operations reset the RSM to complete the Train B reset. The second technician returned to the ESAS cabinet and directed the first technician to perform the reset of Train B EFW Bus 1 Trip. The first technician, expecting his next action to be the trip of Train B EFW Bus 2, placed Bus 2 in the tripped condition. This put both buses of Train B EFW in trip and caused the actuation of P-7A EFW Pump. This inadvertent actuation was caused by human error and was not a valid signal resulting from parameter inputs. The 1992 Statements of Consideration define an invalid signal to include human error. Therefore, this actuation is considered invalid. This event was entered into ANO's corrective action program for resolution. This event did not result in any adverse impact to the health and safety of the public. The plant responded as expected. In accordance with 10 CFR 50.73(a)(i) a telephone notification is being made in lieu of submitting a written Licensee Event Report. The licensee has notified the NRC Resident Inspector. | |
| ENS 54108 | 11 June 2019 16:57:00 | Arkansas Nuclear | NRC Region 4 | A non-licensed contract employee supervisor had a confirmed positive for a controlled substance during a pre-access fitness for duty test. The individual's unescorted access to the plant has been terminated and the badge removed. | |
| ENS 54091 | 26 May 2019 09:25:00 | Arkansas Nuclear | NRC Region 4 | This is a 4-hour Non-Emergency 10 CFR 50.72(b)(2)(iv)(B) notification due to a Plant Protection System (PPS) actuation. Arkansas Nuclear One, Unit 2, automatically tripped from 100 percent power at 0512 CDT. The reactor automatically tripped due to 2P-32B Reactor Coolant Pump tripping as a result of grounding. No additional equipment issues were noted. All control rods fully inserted. Emergency Feedwater (EFW) actuated and was utilized to maintain Steam Generator (SG) levels. The EFW actuation meets the 8-hour Non-Emergency Immediate Notification Criteria of 10 CFR 50.72(b)(3)(iv)(A). No Primary safety valves lifted. Main Steam Safety Valves (MSSVs) did lift initially after the trip. The NRC Resident Inspector has been notified. Decay heat is being removed via the steam dump valves to the main condenser. Unit 2 is in a normal shutdown electrical lineup. Unit 1 was not affected by the transient on Unit 2. The licensee notified the State of Arkansas. | |
| ENS 54073 | 20 May 2019 00:02:00 | Arkansas Nuclear | NRC Region 4 | On May 19, 2019, at 1809 CDT, the Safety Parameter Display System (SPDS) was lost to both Arkansas Nuclear One Units 1 and 2 due to the SPDS Inverter (2Y-26) failure. The SPDS Inverter is the power supply to both units' SPDS. The Unit 2 Control Room dispatched operators in response to a smoke alarm received from the 2Y-26 Inverter room. Upon arrival, smoke was reported emanating from 2Y-26. There was no report of fire at any time. Field operators de-energized 2Y-26 and the smoke ceased. The loss of SPDS also caused the Power Operating Limits (POL) function of the Unit 2 Core Operating Limits Supervisory System (COLSS) to be lost, so Unit 2 reduced power to 91 (percent) in accordance with Technical Specifications. Both units are at power and stable. The NRC Resident has been notified. This is reportable per 10 CFR 50.72(b)(3)(xiii). | |
| ENS 53793 | 18 December 2018 15:40:00 | Arkansas Nuclear | NRC Region 4 | On December 18, 2018 at 1126 CST, Arkansas Nuclear One, Unit 1 (ANO-1) reactor automatically tripped due to a loss of the A-1, non-vital 4160V bus. All control rods fully inserted. Loss of the A-1 bus resulted in de-energizing A-3 vital 4160V bus. Emergency Diesel Generator #1, K-4A, started automatically and is currently powering A-3 vital bus. Non-vital buses A-2, H-1, and H-2 and vital bus A-4 transferred power automatically to the Startup Transformer #1. Off-site power remains energized and available for ANO-1. The reason for loss of A-1 bus is unknown at this time. Currently, ANO-1 has stabilized in Mode 3, Hot Standby. Decay heat is being removed by the main condenser using the turbine bypass valves. The loss of the A-1, non-vital bus, is under investigation. The licensee has notified the NRC Resident Inspector and the state. | |
| ENS 53777 | 5 December 2018 14:54:00 | Arkansas Nuclear | NRC Region 4 | This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Engineered Safety Feature actuation signal. On October 9, 2018, Arkansas Nuclear One, Unit 2 was in refueling Mode 6, when a vital inverter failed while aligned from its alternate power source causing a loss of one of four vital instrument buses. The loss of the instrument bus resulted in one of the four engineered safety feature protection channels to enter a tripped state. Because one of the other four channels was already in a tripped state in support of a channel power supply replacement activity, two out of four protection channels were now in the tripped state resulting in a Safety Injection Actuation Signal, Containment Spray Actuation Signal, Containment Cooling Actuation Signal, Recirculation Actuation Signal, Emergency Feed Actuation Signal, and Containment Isolation Actuation Signal. In general, only one train of equipment is protected and assumed to be available during Mode 6 operations. Due to the defense-in-depth plant configuration in Mode 6, which is intended to avoid inadvertent start of emergency systems, the resulting actuations caused no adverse impact to Shutdown Cooling or Spent Fuel Pool cooling operations. At least one train of the following systems was aligned for automatic actuation: Service Water Emergency Diesel Generator Containment Penetration Room Exhaust Fan Other non-essential components which are shed or realigned upon safeguards actuation The few systems and components that were aligned for automatic operation responded as designed, including containment isolation valves and valves associated with the above systems (if aligned for automatic operation). The Service Water system was already in operation and, therefore, no Service Water pumps actuated. All systems and components which were capable of automatic operation performed as designed. The Emergency Diesel Generator started but did not synchronize to the bus. No safety injection occurred to the core. This actuation was caused by equipment failure and was not an actual signal resulting from parameter inputs. The affected actuation signals do not perform a safety function in Mode 6 and are not required to be available or operable. Therefore, this actuation is considered invalid. This event was entered into ANO's corrective action program for resolution. This event did not result in any adverse impact to the health and safety of the public. In accordance with 10 CFR 50.73(a)(i) a telephone notification is being made in lieu of submitting a written Licensee Event Report. The licensee has notified the NRC Resident Inspector. | |
| ENS 53459 | 16 June 2018 15:56:00 | Arkansas Nuclear | NRC Region 4 | At 1121 CDT on June 16, 2018, Arkansas Nuclear One, Unit 1 (ANO-1) performed a manual reactor trip due to a Turbine Bypass valve failing open on reactor startup. At the time, ANO-1 was in Mode 2 at approximately 2 percent power. The failed Turbine Bypass valve resulted in an overcooling event and the Overcooling Emergency Operating Procedure (EOP) was entered. Main Steam Line Isolation (MSLI) automatic actuation occurred on 2 of the 4 channels of Emergency Feedwater Initiation and Control during the overcooling event in the 'B' Steam Generator. The remaining channels of MSLI were manually actuated by the control room staff from the control room. Overcooling was terminated after the closure of the Main Steam Isolation Valve (MSIV) and reactor coolant parameters were stabilized as directed by the Overcooling EOP. Additionally, Gland Sealing Steam was lost to the main turbine due to the closure of the 'B' Steam Generator MSIV and Loss of Condenser Vacuum Abnormal Operating Procedure was entered. This is a 4-hour non-emergency 10 CFR 50.72 (b)(2)(iv)(B) notification due to a Reactor Protection System actuation (scram) and an 8-hour non-emergency 10 CFR 50.72 (b)(3)(iv)(A) notification for safety system actuation." All control rods fully inserted into the core during the trip. Heat removal is via the Atmospheric Dump Control valves to atmosphere. The NRC Resident Inspector has been notified. The licensee also notified the State of Arkansas. | |
| ENS 53456 | 12 June 2018 22:11:00 | Arkansas Nuclear | NRC Region 4 | On June 12, 2018, at 1500 CDT, a Reactor Coolant System (RCS) Pressure Boundary leak was identified during a Mode 3, hot shutdown walkdown on a High Pressure Injection Line (HPI) to Reactor Coolant Pump (P32C) drain line weld near MU-1066A HPI Line Drain Valve and MU-1066B HPI Line Drain Valve. The 3/4 inch drain line containing drain valves MU-1066A and MU-1066B on the 'C' HPI header (CCA-5 pipe class) has a through-wall defect on the pipe stub or welds between the sockolet and valve MU-1066A. The leak location is in the ASME Class I RCS Pressure Boundary. The hot shutdown walkdown was being performed as part of a planned outage to investigate excessive Reactor Building Sump inleakage. Total unidentified RCS leakage prior to the investigation was determined to be at 0.165 gpm. After the initial investigation of the leakage, the following Tech Specs (TS) were determined be applicable: TS 3.4.5 - RCS Loops Mode 3, TS 3.4.13 - RCS Leakage, TS 3.5.2 - ECCS. Unit 1 is currently in Mode 3 and in progress of an RCS cooldown to comply with Tech Spec requirements. The licensee notified the NRC Resident Inspector. | |
| ENS 53404 | 16 May 2018 22:19:00 | Arkansas Nuclear | NRC Region 4 | At 1750 CDT, the Arkansas Nuclear One, Unit 1 (ANO-1) reactor tripped due to the trip of the 'B' Main Feedwater Pump. Unit 1 was at 10 percent power with escalation of power in progress with one Main Feedwater Pump in service. Investigation is in progress as to the cause of the Main Feedwater Pump trip. The Main Feedwater Pump trip resulted in RPS (reactor protection system) actuation on loss of both Main Feedwater Pumps and resulted in Emergency Feedwater (EFW) actuation. All Control Rods inserted into the core properly and the reactor was verified shutdown. EFW experienced a half-trip on the 'A' train of Emergency Feedwater Initiation and Control (EFIC) at time of system actuation, but was successfully actuated manually immediately upon discovery. Train 'B' EFIC actuated in Automatic as designed. The half-trip of the 'A' train of EFIC is currently believed to be associated with EFIC Channel 'C'; however, investigation is underway to verify this. Currently, ANO-1 has been stabilized and is being maintained in Mode 3 with Auxiliary Feedwater in service. Heat removal is via Turbine Bypass valves to the Condenser. No radiological releases have occurred due to this event. There was no effect on Arkansas Nuclear One, Unit 2. The licensee notified the NRC Resident Inspector and the State of Arkansas. | |
| ENS 52710 | 26 April 2017 14:49:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | At 1004 CDT, Arkansas Nuclear One, Unit 1 (ANO-1) reactor automatically tripped due to the partial loss of offsite power. At the time of the trip, the site was in a Tornado Warning and a Severe Thunderstorm Warning. The Emergency Feedwater (EFW) system auto-actuated due to the loss of main feedwater pumps and the loss of the Reactor Coolant pumps. Both Emergency Diesel Generators started as expected with only one loading as expected. All control rods fully inserted. Currently, ANO-1 has stabilized in Hot Standby via natural circulation. ANO-1 also lost Spent Fuel Pool cooling for approximately 69 minutes. The temperature of the spent fuel pool at the beginning of the event was approximately 102 (degrees) F. The spent fuel pool saw a heatup of 1 (degree) F during the loss of spent fuel pool cooling. The Spent Fuel Pool cooling has been restored. ANO-2 is currently in a refueling outage with all fuel in the spent fuel pool. ANO-2 completed a full core off load to the spent fuel pool and this was completed on April 12, 2017. Spent Fuel Pool cooling was lost for approximately 10 minutes. The Spent Fuel Pool temperature was 91 (degrees) F prior to the event. No heat up of the pool was identified during the event. Cooling has subsequently been restored. The #1 Emergency Diesel Generator auto-started as designed but did not supply the safety bus due to availability of offsite power. No radiological releases have occurred from either unit due to this event. The licensee has notified the NRC Resident Inspector. |
| ENS 52441 | 17 December 2016 05:43:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | At approximately 1400 CST on 12/16/16, during the performance of VEF-38A Lead Penetration Room Ventilation System (PRVS) Exhaust Fan Monthly Test, flow was found to be at 2000 SCFM with an operability limit of 1620 to 1980 SCFM. VEF-38A was declared inoperable. Unit 1 entered Technical Specification Limiting Condition for Operation (LCO) 3.7.11 Condition C for both trains of PRVS inoperable. With VEF-38A aligned as the lead fan and capable of auto-start, the operable standby fan (VEF-38B) would not have started. During the time that VEF-38A was inoperable and capable of auto-starting, the Unit 1 PRVS was in a condition that could have prevented the control of the release of radioactive material. At 1546 CST on 12/16/16, Unit 1 rendered VEF-38A incapable of auto starting by placing its hand switch in PULL-TO-LOCK. Unit 1 Entered LCO 3.7.11 condition A for one PRVS train inoperable and Exited LCO 3.7.11 Condition C. This is a notification per 10 CFR 50.72(b)(3)(v) for a condition that could have prevented the control of the release of radioactive material. The licensee has notified the NRC Resident Inspector.
EN 52441 was initiated on December 16, 2016, when the VEF-38A fan flow was found to be in excess of the procedurally defined operability limit during the monthly lead penetration room ventilation system test. The revision of the procedure in use at the time had inadvertently included acceptance criterion for fan air flow in the monthly supplements. The monthly tests demonstrate the flow paths for the two trains are functional and open, but they are not performed in the designed Engineered Safeguards (ES) configuration. The monthly tests do not secure the normal supply and exhaust ventilation within the penetration room boundaries; therefore, flow may be outside limits required during the ES configuration. The 18 month surveillance, which measures the flowrate of the system while in the ES configuration, was completed in April 2016. The surveillance verified the system's operability. The systems have not been modified or altered since this surveillance; therefore the measured flowrate remains the same. The procedure has been revised subsequent to this event to remove the flowrate as an 'acceptance criterion' for the monthly test. Because the VEF-38A flow did not result in fan inoperability, both fan trains remained operable; therefore, ANO-1 did not lose a safety function to control a radioactive release. Based on that, conclusion EN 52441 is being retracted. The licensee will notify the NRC Resident Inspector. Notified R4DO (Warnick). |
| ENS 52271 | 30 September 2016 04:01:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | At 2100 CDT on 09/29/16, while in Mode 6, both trains of Decay Heat (Residual Heat Removal) were declared inoperable due to a cracked weld on a 1" common pipe. The leak developed in a USAS B31.7, Class1 pipe at a weld upstream of pressure indication isolation valve DH-1037. The leak is not isolable from the common 8-inch Decay Heat piping and encompasses approximately 1/3 (one third) of the pipe circumference. At the time of discovery, the unit was in Lowered Inventory with both Loops of Decay Heat in service. Subsequently, one train of Decay Heat has been secured to reduce the likelihood of crack propagation. One Train of Decay Heat remains in service providing the function of removing Decay Heat and the other train is readily available. The leakage impacts redundant equipment required to fulfill a safety function. In the current condition, both trains are required to be operable to meet Technical Specification LCO 3.9.5, Decay Heat Removal (DHR) and Coolant Circulation-Low water Level. This condition is reportable per 10 CFR 50.72(b)(3)(v)(B) for any event or condition that results in a loss of Safety Function associated with the Decay Heat System (Residual Heat Removal System). The licensee has notified the NRC Resident Inspector. The leak is approximately 0.25 gallons per minute and pipe pressure is 140 psi. Compensatory measures are in place and include an individual posted to watch the pipe in case plugging is necessary. Repairs to the pipe will be completed once pipe is able to be drained. |
| ENS 52267 | 28 September 2016 09:46:00 | Arkansas Nuclear | NRC Region 4 | CE | On September 16, 2016, at 0036 (CDT), during a 24-hour Technical Specification (TS) endurance run, the Arkansas Nuclear One, Unit 2 (ANO-2) red train Emergency Diesel Generator (EDG) became inoperable when its inboard generator bearing failed. ANO-2 TS 3.8.1.1, 'AC Sources', requires an inoperable EDG to be restored to service within 14 days or actions to place the unit in a shutdown condition initiated. It has been determined that repair options cannot be completed within the Allowed Outage Time (AOT) due to unforeseen circumstances which evolved during recovery efforts. At 0745 (CDT), ANO-2 initiated plant shutdown due to the inability to restore the red train EDG. ANO-2 will be shutdown and cooled down to Mode 5. The licensee informed the NRC Resident Inspectors. |
| ENS 52242 | 15 September 2016 11:18:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornadoes, Arkansas Nuclear One, Unit 1, identified non-conforming conditions in the plant design such that specific TS equipment on Unit 1 is considered not (to) be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering vital switchgear rooms 99 and 100 and striking vital switchgears in the rooms. A tornado could generate multiple missiles capable of striking the Unit 1 vital switchgear and rendering both safety related AC electrical trains 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) safe shutdown capability, (B) residual heat removal capability, or (D) accident mitigation. This condition was identified as part of an on-going extent of condition review of potential tornado missile related site impacts. Licensee Event Report (LER) 50-313/2016-002-00 was recently submitted addressing previously identified tornado missile vulnerabilities at the Unit 1 plant. 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 52234 | 11 September 2016 17:44:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornados, Arkansas Nuclear One, Unit 1, identified non-conforming conditions in the plant design such that specific TS equipment on Unit 1 is considered not be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering the Unit 1 Controlled Access area, elevation 386', Upper North Electrical Penetration Room (UNEPR) through penetrating a hollow metal door and then striking safety related cables. A tornado could generate multiple missiles capable of striking the Unit 1 UNEPR and rendering both safety related emergency feedwater trains 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)(B) and (D) 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 (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. Licensee Event Report (LER) 50-313/2016-002-00 was recently submitted addressing previously identified tornado missile vulnerabilities at the Unit 1 plant. 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. A similar evaluation is on going for Unit 2. |
| ENS 52195 | 24 August 2016 12:15:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornados, Arkansas Nuclear One, Unit 1, identified non-conforming conditions in the plant design such that specific TS equipment on Unit 1 is considered to not be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering the Unit 1 Cable Spreading Room through penetrating the hollow metal door or potentially from spalling of the block wall separating Room 96 and 97. A tornado could generate multiple missiles capable of striking the Unit 1 Cable Spreading Room and rendering both safety related electrical trains 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. Licensee Event Report (LER) 50-313/2016-002-00 was recently submitted addressing previously identified tornado missile vulnerabilities at the Unit 1 plant. 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 51949 | 23 May 2016 15:36:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | A non-licensed employee supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector. |
| ENS 51891 | 29 April 2016 10:48:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | The licensee notified the Arkansas Department of Emergency Management, National Response Center, and Local Emergency Planning Committee regarding an onsite spill of 12 (percent) Sodium Hypochlorite (bleach solution). Approximately 2000 gallons of Sodium Hypochlorite solution leaked from a bulk tank within the protected area, outside the tank containment berm. Approximately 100 gallons were estimated to have entered the nearby storm drain. The estimate was based on preliminary chemistry samples. The quantity released exceeded the Reportable Quantity (RQ) for Sodium Hypochlorite (RQ of 100 pounds) and was therefore reported. There is no impact to the operation of the ANO units or personnel onsite or offsite. No harm to the environment is expected. No offsite emergency response is required. This event is reportable under 10 CFR 50.72(b)(2)(xi) as an event or situation related to the protection of the environment for which a notification to other government agencies have been made. The NRC Resident Inspector has been notified. |
| ENS 51808 | 19 March 2016 22:51:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | Two (2) potentially degraded flood barriers at penetrations 0073-01-0034 and 0073-01-0063 were identified in the area between the Unit 1 Turbine Building and Auxiliary Building. The deficient barriers are a 'blockout section' of the floor designed to house multiple penetrations that transition from the Turbine Building to the Auxiliary Building. Attempts have been made to investigate the status of the flood barrier with no definitive results. Investigations and additional evaluations are continuing, however, it is currently unknown if the aggregate of these two flood barriers could potentially overwhelm and flood the Auxiliary Building which would challenge equipment necessary to remove residual heat and constitute an unanalyzed condition. Based on current conditions (i.e., no forecast flooding conditions), this condition does not present an immediate safety concern. This condition has been determined to be reportable per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(B). This condition is a non-emergency condition. This condition has been entered into the Corrective Action Program. Compensatory measures have been prepared to allow placement of a seal over the identified deficient barriers. If required these seals can be installed well in advance of forecast flood conditions. Permanent repairs are currently being designed for installation. The NRC Resident Inspector has been notified.
This is an 8 hour non-emergency supplemental notification to previously issued Event Notification number 51808. In EN 51808, two non-functional barriers were identified and reported, and during an extent of condition review, a third barrier has been identified that does not conform to expected flood barrier standards A potentially degraded flood barrier at 'blockout' penetration 0073-01-9018 was identified in the area between the Unit 1 Turbine Building and Auxiliary Building. The deficient barrier is a 'blockout section' of the floor designed to house multiple penetrations that transition from the Turbine Building to the Auxiliary Building. Attempts have been made to investigate the status of the flood barrier with no definitive results. Investigations and additional evaluations are continuing; however, it is currently unknown if this flood barrier could potentially be overwhelmed and flood the Auxiliary Building which would challenge equipment necessary to remove residual heat and constitute an unanalyzed condition. Based on current conditions (i.e., no forecast flooding conditions), this condition does not present an immediate safety concern. This condition has been determined to be reportable per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(B). This condition is a non-emergency condition. This condition has been entered into the Corrective Action Program. Compensatory measures have been prepared to allow placement of a seal over the identified deficient barrier. If required this seal can be installed well in advance of forecast flood conditions. Permanent repairs are currently being designed for installation. The NRC Resident Inspector was notified earlier in the evening that this event would be updated. Notified the R4DO (Haire). |
| ENS 51785 | 10 March 2016 09:44:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | This notification is being made due to planned maintenance during the Semi-Annual Seismic System Functional Test. This test will result in a major loss of emergency assessment capability for emergency action levels (EAL) HA6 (Natural or destructive phenomena affecting VITAL AREAS), while the control room 0.1g acceleration alarm is non-functional. The emergency preparedness plan requires the 0.1g acceleration alarm indication to declare EAL HA6 during a seismic event > Operating Basis Earthquake (OBE). This condition requires an 8 hour nonemergency immediate reportability to the NRC in accordance with 10 CFR 50.72(b)(3)(xiii), Major Loss of Assessment, Response, or Communication Capability. At approximately 0840 CST on March 10, 2016 the Semi-Annual Seismic System Functional Test commenced. While this test is in progress, seismic alarm capability is not available for EAL declaration purposes. ANO procedures provide compensatory measures of using offsite sources to obtain seismic data. It should be noted that seismic data will still remain capable of being recorded and only alarm capability is lost. The Semi-Annual Seismic System Functional Test is scheduled to be completed in less than 24 hours. The licensee will inform the NRC Resident Inspector. |
| ENS 51711 | 4 February 2016 18:50:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | A non-licensed supervisor tested positive for a drugs during a random Fitness for Duty test. The individual's access to the plant has been suspended. The NRC Resident Inspector has been informed. |
| ENS 51607 | 15 December 2015 10:24:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | This is a 4-hour Non-Emergency 10 CFR 50.72(b)(2)(iv)(B) notification due to a Reactor Protection System (RPS) actuation. Arkansas Nuclear One, Unit 1, was manually tripped from 43 percent power at 0544 CST. The reactor was manually tripped due to operator judgement during control issues with the Integrated Control System (ICS) during a planned downpower for Electro-Hydraulic Control (EHC) system maintenance. CV-2672 B, low load control valve, failed to close. Subsequently, CV-2674 B, low load block valve, began to close and caused a loss of feed to E-24B Steam Generator. No additional equipment issues were noted. All control rods fully inserted. Emergency Feedwater (EFW) actuated and was utilized to maintain Steam Generator (SG) levels. This (EFW actuation) meets the 8 hour Non-Emergency Immediate Notification Criteria ((10CFR50.72(b)(3)(iv)(A)). No Primary safety valves lifted. Main Steam Safety Valves (MSSVs) did lift initially after the trip. The NRC Resident (Inspector) has been notified. Decay heat is being removed via the steam dump valves to the main condenser. Unit 1 is in a normal shutdown electrical lineup. Unit 2 was not affected by the transient on Unit 1. The licensee notified the State of Arkansas. |
| ENS 51543 | 17 November 2015 12:11:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | This notification is being made due to planned maintenance during the Semi-Annual Seismic System Functional Test. This test will result in a major loss of emergency assessment capability for emergency action level (EAL) HA6 (natural or destructive phenomena affecting VITAL AREAS), while the control room 0.1g acceleration alarm is non-functional. The emergency preparedness plan requires the 0.1g acceleration alarm indication to declare EAL HA6 during a seismic event greater than the Operating Basis Earthquake (OBE). This condition requires an 8 hour non-emergency immediate reportability to the NRC in accordance with 10 CFR 50.72(b)(3)(xiii), Major Loss of Assessment, Response, or Communication Capability. At approximately 1200 CST on November 17, 2015, the Semi-Annual Seismic System Functional Test will commence. While this test is in progress, seismic alarm capability is not available for EAL declaration purposes. ANO procedures provide compensatory measures of using offsite sources to obtain seismic data. It should be noted that seismic data will still remain capable of being recorded and only alarm capability is lost. The Semi-Annual Seismic System Functional Test will occur intermittently over the next four days. The licensee has notified the NRC Resident Inspector.
The licensee returned the Seismic System to service at 1347 CST on 11/18/15. The licensee notified NRC Resident Inspector. Notified the R4DO (Warnick). |
| ENS 51340 | 24 August 2015 11:36:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | This notification is being made in accordance with 10 CFR 50 72(b)(3)(xiii) as an event that will result in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g. a significant portion of control room indication, Emergency Notification System or offsite notification system.) The emergency preparedness plan requires seismic monitoring instruments to diagnose an earthquake for emergency actions levels (EAL) HU6 (Natural or destructive phenomena affecting protected area) and HA6 (Natural or destructive phenomena affecting vital areas). At 1020 CDT on August 24, 2015 the Semi-Annual Seismic System Functional Test commenced. While this test is in progress, seismic alarm capability is not available for EAL declaration purposes. ANO procedures provide compensatory measures of using offsite sources to obtain seismic data. It should be noted that seismic data will still remain capable of being recorded, only alarm capability is lost. The licensee notified the NRC Resident Inspector. |
| ENS 51184 | 27 June 2015 06:40:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) as an event that will result in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g. significant portion of control room indication, Emergency Notification System or offsite notification system.) The emergency preparedness plan requires seismic monitoring instruments to diagnose an earthquake for emergency action levels (EAL) HU6 (Natural or destructive phenomena affecting Protected Area) and HA6 (Natural and destructive phenomena affecting Vital Areas). At 2149 CST on June 26, 2015, (the) ACS-8003 seismic monitor was declared non-functional due to having a fault light indicated on the C529 seismic cabinet. (The) ACS-8001 seismic monitor had previously been declared non-functional due to the same condition. With these 2 monitors out of service the seismic alarm capability is not available. ANO procedures provide compensatory measures of using offsite sources to obtain seismic data. The NRC Resident Inspector has been notified.
On 6/28/15 at 1232 CDT, batteries have been replaced in ACS-8001 and ACS-8003 seismic monitors. Both monitors have been restored to a fully functional status. Seismic alarm capability is restored and Emergency Assessment Capability has been restored. The licensee will notify the NRC Resident Inspector. Notified R4DO (Campbell). |
| ENS 51029 | 1 May 2015 16:14:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | This notification is conservatively being made in accordance with 10 CFR 50.72(b)(3)(xiii) as an event that will result in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g. significant portion of control room indication, Emergency Notification System or offsite notification system.) The emergency preparedness plan requires seismic monitoring instruments to diagnose an earthquake for emergency action levels (EAL) HU6 (Natural or destructive phenomena affecting PROTECTED AREA) and HA6 (Natural and destructive phenomena affecting VITAL AREAS). At approximately 1600 (CDT) on May 1, 2015, ANO plans to remove Motor Control Center B33 from service for maintenance. This will render the alarm functions for the seismic monitors nonfunctional. It is expected that this maintenance will take approximately 72 hours to complete. ANO procedures provide compensatory measures of using offsite sources to obtain seismic data. The NRC Resident Inspector has been notified. |
| ENS 50739 | 15 January 2015 17:29:00 | Arkansas Nuclear | NRC Region 4 | CE | This notification is being made in accordance with NUREG-1022, Event Report Guidelines 10 CFR 50.72 and 50.73 Section 3.2.12, News Release or Notification of Other Government Agency. On January 15, 2015 at 0720 CST, with Arkansas Nuclear One, Unit 2 (ANO-2) at 100% power, an on-site injury occurred on ANO-2. An individual fell while descending stairs and was injured. Pope County EMS transported the individual to a local medical facility. No contaminated individuals were transported off-site. No individuals were contaminated during the event. The individual was admitted to the local hospital. 29 CFR 1904.39(a) requires a report to the Occupational Safety and Health Administration (OSHA), US Department of Labor with twenty-four (24) hours after the in-patient hospitalization of one or more employees as a result of a work-related incident. At 1545 CST, ANO determined that this is a 24-hour OSHA reportable occurrence. The licensee notified the NRC Resident Inspector. |
| ENS 50641 | 25 November 2014 17:07:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | On Tuesday November 25, 2014, at 1211 CST, Arkansas Nuclear One, Unit 1 (ANO-1) reviewed AREVA 10 CFR 50.46 Notification Letter FAB14-00632. This letter indicates that a deficiency was discovered in the uranium thermal conductivity models used in the ANO-1 Loss of Coolant Accident (LOCA) analysis of record. When the deficiency is corrected, the LOCA Peak Cladding Temperature (PCT) limits may be in excess of 2200 degrees Fahrenheit (F). 10 CFR 50.46 paragraph (b) defines the acceptance criteria for the LOCA analysis process. The ANO-1 licensing basis PCT is evaluated for compliance with the criterion 10 CFR 50.46(b)(1) and must not exceed a PCT of 2200 degrees F. During AREVA's review of the issue, AREVA had provided compensatory measures in the form of reductions in LOCA linear heat rates as a contingency in case the errors were found to be substantiated, which were then translated into reduced axial imbalance limits so that ANO-1 would operate within 10 CFR 50.46 limits. As a precautionary measure pending the completed analysis, ANO-1 implemented the compensatory measures on October 20, 2014, and as a result, the errors reported have no impact on current plant operation or public health and safety. This event is being conservatively reported in accordance with 10 CFR 50.72(b)(3)(ii)(B). Based on 50.46(a)(3)(ii) criteria, ANO-1 will submit a written report within 30 days. ANO-1 has notified the NRC Senior Resident Inspector. |
| ENS 50519 | 8 October 2014 15:39:00 | Arkansas Nuclear | NRC Region 4 | CE | INPO-IER-L4-14-33 (Direct Current Circuits Challenge Appendix R Fire Analysis) was reviewed to determine applicability to ANO Unit 1 & 2. It was determined that 2P-21, Turbine Generator Emergency Seal Oil Pump, control cables are not fused and are routed through multiple fire zones containing safe shutdown equipment. A potential fire induced cable failure in any of these fire zones could result in a secondary fire or damage adjacent cables along the path of the unprotected cable. The concern is that under fire safe shutdown conditions, it is postulated that a fire in one zone can cause short circuits potentially resulting in secondary fires or cable failures in other fire zones where the cables are routed. The secondary fires or cable failures are outside the assumptions of the 10 CFR 50 Appendix R Safe Shutdown Analysis. This condition is reportable as an 8-hour ENS report in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition. Compensatory measures (fire watches) have been implemented for affected zones of the plant. The NRC Resident Inspector has been notified. |
| ENS 50454 | 12 September 2014 20:42:00 | Arkansas Nuclear | NRC Region 4 | B&W-L-LP | Arkansas Nuclear One (ANO) identified the potential for stored fuel that does not meet the fuel specifications or loading conditions of the Certificate of Compliance (CoC) for the HI-STORM 100 Cask System. Investigation into the cause of a Control Room Emergency Ventilation System (CREVS) actuation on the morning of 9/12/2014 led to sampling of helium circulating through the Multi-Purpose Canister (MPC-24-060) as part of the Forced Helium Dehydration process in the final stages of cask loading. Sample results indicated the presence of Kr-85. Kr-85 is a fission product that indicates the potential for the fuel that does meet the selection criteria for the HI-STORM 100 Cask System. All fuel assemblies loaded into MPC-24-060 were checked to confirm their intact status (a cask Certificate of Conformance requirement) as part of the selection process. Each assembly's status as intact is based on in-mast sipping and/or ultrasonic testing performed subsequent to their final operating cycle. Results of these sipping and ultrasonic test campaigns are maintained in a comprehensive engineering report used to verify assembly status during cask fuel selection. Per the CoC for the Hi-STORM 100 Cask System, Appendix B, Section 1.0, the definition of 'INTACT FUEL ASSEMBLY' is a fuel assembly without known or suspected cladding defects greater than pinhole leaks or hairline cracks, and which can be handled by normal means. Given the presence of Kr-85 along with the fuels history, it cannot be confirmed that all fuel assemblies meet the definition of 'Intact' and would not meet the CoC Requirements for Fuel to be stored in the HI-STORM 100 SFSC System (Section 2.1.1). The NRC Resident Inspector has been notified. |
| ENS 50138 | 24 May 2014 13:51:00 | Arkansas Nuclear | NRC Region 4 | CE | Offsite notification has been made to the Arkansas Department of Health due to Pope county EMS rescue personnel entering a radiological / contaminated area. An individual was working in a radiological / contaminated area only accessible by ladder. The individual was unable to use a ladder to egress the area and requested assistance in exiting. Pope county EMS rescue with the on-site rescue team provided the necessary assistance which required the team to enter a radiological / contaminated area. The team, including the individual in question, has exited the radiological / contaminated area. They were evaluated by Radiation Protection and were not contaminated. The individual was transported to a local medical facility for further evaluation. The individual was assisted in exiting the 'A' steam generator cavity. The licensee has notified the NRC Resident Inspector. |
| ENS 50063 | 27 April 2014 23:57:00 | Arkansas Nuclear | NRC Region 4 | CE | At approximately 1932 (CDT) on 4/27/2014, the System Operations Center (SOC - Dispatcher) informed Unit 2 of a system wide grid emergency and ordered both Unit 1 and Unit 2 to come off line as soon as possible. At approximately 2012 (CDT), Unit 2 automatically tripped from 51% power due to an Auxiliary Trip on CPCs (Core Protection Calculator) due to Axial Shape Index (ASI) trip. All Control Element Assemblies inserted into the core. Both vital and non-vital 4160V and 6900V buses remain powered from Startup #3 Transformer. All Systems responded as designed. At 1932 (CDT), Unit 1 commenced a Rapid Plant Shutdown at a rate 5-7% per min with the intention to take the turbine offline and leave the reactor critical at 10-12% power on the Turbine Bypass Valves. When the Unit 2 reactor tripped, Unit 1 stopped the power reduction and stabilized the plant at approximately 19% Reactor Power and 125 Generated Megawatts. With SOC concurrence, Unit 1 stabilized power and was told to limit site output to <200 MWe. At 1932 CDT, Unit 1 began a down power from 100% power and Unit 2 began a down power from 95% power. On Unit 2, decay heat is being removed by the main condenser using the turbine bypass valves. Unit 2 is stable in Mode 3 with stable offsite power. The system wide grid emergency is believed to be caused by tornados in the region. The licensee has notified the NRC Resident Inspector and the State. |
| ENS 49995 | 3 April 2014 17:08:00 | Arkansas Nuclear | NRC Region 4 | CE | At approximately 1301 (CDT) on 4/3/2014, Unit 2 tripped from 100% power for unknown reason(s). All Control Element Assemblies (CEA) inserted into the core. (Note that CEA 03 Plant Monitoring System indication still indicates fully withdrawn. However, CEA 03 in-limit light and control panel indication validate that CEA 03 is fully inserted.) 4160v bus 2A1 and 6900v bus 2H1 transferred to Startup Transformer #2. 4160v bus 2A2 appeared to de-energize and re-energize on Startup Transformer #3. 6900v bus 2H2 is de-energized. 2K4B emergency diesel generator started but did not tie onto the 2A4 4160v bus. Emergency Feedwater actuated on low steam generator level. Offsite power remains available and decay heat is being removed to the main condensers using the turbine bypass valves. Unit 1 was not affected. The licensee has notified the NRC Resident Inspector and will notify the State. |
| ENS 49873 | 5 March 2014 11:20:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | During walk downs to ensure the availability of flood protection barriers, a condition was identified which had the potential to adversely impact the ability to address external flooding conditions. Several individual pathways between both unit's Turbine Building and Auxiliary Building were identified that could bypass flood barriers. In the aggregate however, the current equipment could become overwhelmed and the flooding in the Auxiliary Building could then potentially challenge equipment necessary to remove residual heat. The identified pathways were for the most part unscheduled partially filled conduits. There were no isolation features on these pathways and no barriers to flooding were in place between the Turbine Building and Auxiliary Building thus the potential existed to bypass the existing flood barriers. Flooding of the Turbine Building conceivably could have resulted in the accumulation of water in sufficient quantities to fill the Turbine Building to the height of the external floodwaters which could enter the Auxiliary Building via one or more deficient flood barrier. These floodwaters would then potentially challenge equipment, located within the Auxiliary Building, which is required to remove residual heat. This condition has been determined to be reportable per 10CFR50.72(b)(3)(v)(B) and 10CFR50.72(b)(3)(ii)(B). This condition is a non-emergency condition. This condition has been entered into the Corrective Action Program. Barriers are being installed in these pathways as they are identified or compensatory measures implemented. The walk downs were performed in response to Fukishima lessons learned. The licensee notified the NRC Resident Inspector. |
| ENS 49618 | 9 December 2013 09:20:00 | Arkansas Nuclear | NRC Region 4 | CE | At approximately 0748 (CST) on 12/9/2013, an electrical fault occurred resulting in a fire and explosion on the ANO (Arkansas Nuclear One) Unit 2 Unit Auxiliary Transformer. This caused a unit trip and a loss of power to Startup 3 Transformer, which is one of the two offsite power feeds to ANO Unit 2. ANO Unit 2 is currently in a stable shutdown condition. With Startup 3 and Unit Aux Transformer unavailable, power was lost to the Reactor Coolant Pumps and Circulating Water Pumps. RCS (Reactor Coolant System) natural circulation is in progress removing core decay heat. Emergency Feedwater actuated due to low steam generator levels and is supplying both steam generators. The unit is steaming to the atmosphere. 2A-1 and 2A-3 are powered from SU (Startup) 2 Transformer. 2A-4 is powered from 2K-4B Emergency Diesel Generator. ANO Unit 1 is currently operating at 98% power. The auto transformer tripped off line with the fault in ANO Unit 2 Unit Auxiliary Transformer. This has caused Startup Transformer 1 to be inoperable. This places ANO Unit 1 in a 72 hour Technical Specification action statement (T.S 3.6.1 for Loss of the SU-1 Transformer). No significant injuries were reported as a result of this condition and offsite agencies have been notified. At 0800 on 12/9/2013 Unit 2 declared a Notification of Unusual Event based on EAL HU4 Fire or Explosion inside Protected Area not extinguished in 15 minutes. At 0917 on 12/9/2013, the fire on Unit 2 Unit Auxiliary Transformer is OUT. The Licensee notified the NRC Resident Inspector. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA Ops Center, EPA EOC, and Nuclear SSA vial email.
At 1215 CST, ANO terminated from the Unusual Event as per HU4 stable plant conditions. ANO Unit 2 is stable and will be cooled down to Mode 5 via natural circulation and decay heat is being removed via emergency feedwater and downstream dump valves to atmosphere. There is no radiological release and no personnel injuries. The licensee has notified the NRC Resident Inspector, Arkansas Department of Emergency Management, Arkansas Department of Health, and other local authorities. Notified R4DO (Vasquez), NRR EO (King) and IRC MOC (Morris). Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, NICC Watch Officer, USDA Ops Center, EPA EOC, and Nuclear SSA vial email.
Outside agencies (National Response Center, Arkansas Department of Emergency Management, Corps of Engineers, and U.S. Coast Guard) were contacted due to a minor unknown amount of oil that entered the plant discharge to Lake Dardanelle. The oil was from the faulted Unit 2 Unit Auxiliary Transformer. The majority of oil was contained within the containment around the transformer or the oily water separator it drains to. Local inspection revealed only a small amount of what was released actually passed the containment booms that are continuously in place on the discharge canal. The oil boom was verified to be in good condition. The oil was verified to be mineral oil. The release was verified to be terminated. An additional oil boom was deployed. Reference (ANO) Condition Report CR-ANO-C-2013-03071. The licensee notified the NRC Resident Inspector. Notified the R4DO (Werner) |
| ENS 48955 | 22 April 2013 23:23:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | On 4-22-13, at 1623 (CDT), the ANO Unit 2 control room was notified of a loss of ventilation capability to the Emergency Operations Facility (EOF). The main control boards associated with the variable speed drives on both air handling units at the EOF have failed. Therefore, there are no means to filter air for the EOF. If the EOF is staffed, the EOF will be required to relocate to the Alternate EOF in the event of a release that causes the EOF evacuation criteria to be exceeded, as directed by approved emergency response procedures. The on-site Operations Support Center, on-site Technical Support Center and off-site Alternate EOF remain fully functional to perform emergency assessment activities. Efforts are underway to expedite repairs. This notification is required by 10CFR50.72(b)(3)(xiii). The licensee has notified the NRC Resident Inspector.
At 1637 EDT on 4/23/13, the EOF ventilation has been restored and the EOF has full functionality. The licensee has notified the NRC Resident Inspector. Notified R4DO (Whitten). |
| ENS 48869 | 31 March 2013 11:57:00 | Arkansas Nuclear | NRC Region 4 | CE B&W-L-LP | At 0750 (CDT) on 3/31/2013, during movement of the Unit 1 Main Turbine Generator Stator (~500 tons), the Unit 1 turbine temporary lift device failed. This caused a loss of all off-site power on Unit 1. The ANO Unit 1 #1 and #2 EDG (Emergency Diesel Generator) have started and are supplying A-3 4160V switchgear and A-4 4160V switchgear. P-4A Service Water pump and P-4C Service Water pump has been verified running. Unit 1 has entered (procedures) 1202.007 - Degraded Power, 1203.028 - Loss of Decay Heat, and 1203.050 - Spent Fuel Emergencies. Unit 1 is in MODE 6. ANO-1 entered TS 3.8.2 A, 'One Required Offsite Circuit Inoperable'. All required actions are complete. The event caused a loss of decay heat removal on ANO Unit 1 which was restored in 3 minutes and 50 seconds. Unit 2 tripped and is in MODE 3. Emergency Feed Water was initiated on Unit 2 and Unit 2 was in (Technical Specification) 3.0.3 from 0817 (CDT) to 0848 (CDT) due to Emergency Feedwater. Unit 2 is being powered by off-site. Unit 2 Startup 3 (transformer) lock out at 0921 (CDT). (Bus) 2A1 is on Start up 2 (transformer) and (bus) 2A3 is on #2 EDG. 10CFR50.72 (b)(3)(iv)(A) - 4-hr. notification due to the ES (Engineered Safeguard Feature) actuation on both Unit 1 and Unit 2. 10CFR50 72 (b)(2)(iv)(B) - 4-hr. notification due to RPS (Reactor Protection System) actuation on Unit 2. 10CFR50.72 (b)(2)(xi) - 4-hr. notification due to Government Notification. 29CFR1904.39a - (OSHA) 8-hr. notification due to death on site. At 1033 (CDT) on 3/31/2013, Unit 2 entered a Notification of Unusual Event based on EAL HU4 due to damage in 2A1 switchgear. Notification of the NUE will be made lAW Emergency Plan requirements. Follow-up notifications will be made as appropriate. At this time, the full extent of structural damage on Unit 1 is not known. There was one known fatality and 4 known serious injuries to workers. The local coroner is on site for the fatality and the injured personnel have been transported offsite to local hospitals. Investigation into the cause of the failure and extent of damage is ongoing. On Unit 2, all rods inserted during the trip. The core is being cooled via natural circulation. Decay heat is being removed via steam dumps to atmosphere. There is no known primary to secondary leakage. The licensee has notified the State of Arkansas, local authorities, OSHA and the NRC Resident Inspector. Notified DHS SWO, DHS NICC, FEMA and Nuclear NSSA (via email).
The licensee terminated the NOUE at 1821 CDT. The basis for termination was that the affected bus (2A2) is de-energized and no other equipment on Unit 2 was damaged. The licensee has notified the state and local authorities and will be notifying the NRC Resident Inspector. Notified R4DO (Pick), NRR EO (Howe), IRD (Gott), DHS SWO, DHS NICC, FEMA and Nuclear SSA (via email).
The licensee made the following edits to the third paragraph of their original report (edits in quotes): Unit 2 tripped and is in MODE 3. Emergency Feed Water initiated on Unit 2. Unit 2 was in (Technical Specification) 3.0.3 from 0817 (CDT) to 0848 (CDT) due to Emergency Feedwater "being procedurally overridden." Unit 2 "was initially" being powered by off-site. Unit 2 Startup 3 Lock out occurred at 0921. 2A1 is now on Startup 2, and "2A4" is on #2 EDG. Notified R4DO (Kellar) via email. |