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 Entered dateSiteRegionReactor typeEvent description
ENS 5622114 November 2022 13:05:00OconeeNRC Region 2B&W-L-LPThe following information was provided by the licensee via email: During a scheduled refueling outage, a walkdown inside containment discovered a small amount of boron on the 1B2 Reactor Coolant Pump (RCP) lower bearing temperature instrument. At 0730 EST on November 14, 2022, with Unit 1 in Mode 6, disassembly of the instrument indicated the source of the boron was from a leak in the thermowell. The thermowell is considered part of the reactor coolant system pressure boundary and as such the condition is reportable. Repairs for the condition are in progress. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 561971 November 2022 16:56:00OconeeNRC Region 2B&W-L-LPThe following information was provided by the licensee via email: At 1433 EDT on November 1, 2022, it was determined that a single relevant indication in the RCS pressure boundary did not meet the acceptance criteria under ASME, Section XI IWB-3514-2. 'Allowable Planar Flaws.' The condition will be resolved prior to plant startup. This event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 561404 October 2022 15:54:00Arkansas NuclearNRC Region 4CE
B&W-L-LP
A non-licensed supervisor had a confirmed positive during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified.
ENS 561361 October 2022 00:08:00Arkansas NuclearNRC Region 4CE
B&W-L-LP
A supplemental supervisor violated the station's FFD policy. The individuals access to the plant has been terminated. The licensee notified the NRC Senior Resident Inspector.
ENS 558887 May 2022 04:37:00OconeeNRC Region 2B&W-L-LPThe following information was provided by the licensee via fax: At 2310 EDT on May 6, 2022, with Unit 3 in Mode 3, an actuation of the Emergency Feedwater (EFW) System occurred while entering a planned refueling outage. The reason for the EFW auto-start was a loss of all Main Feedwater (MFDW) Pumps which occurred when the 3A MFDW Pump tripped on steam generator (SG) overfill protection due to high level in the 3B SG. The high level in the 3B SG occurred when a Startup Feedwater Control Valve (3FDW-44) malfunctioned, resulting in excessive feedwater flow to the 3B SG. Investigation and repairs are in progress. Units 1 and 2 were not affected. This event is being reported as an 8-hr non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as a valid actuation of the EFW system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5580023 March 2022 16:43:00OconeeNRC Region 2B&W-L-LPThe following information was provided by the licensee via email and phone: At 1625 (EST) on 2/13/2022, with Unit 2 in Mode 3 at 0 percent power and plant heat up to normal operating temperature in progress, an actuation of the Emergency Feedwater System (EFW) occurred. The reason for the EFW auto-start was lowering water level in the 2A and 2B Steam Generators due to failure of the 2A Main Feedwater Pump to respond as required to maintain Steam Generator water level as Steam Generator pressure increased during plant heat up. The 2A and 2B Motor Driven Emergency Feedwater (MDEFW) pumps automatically started as designed when the 'low steam generator level' signal was received for the 2A and 2B Steam Generators. Following further evaluation, it was determined that a valid EFW actuation occurred, therefore this event is being reported as a late 8-hour non-emergency notification of a valid actuation of the EFW system in accordance with 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5575022 February 2022 01:44:00OconeeNRC Region 2B&W-L-LP

The following information was provided by the licensee via fax or email: At 2207 (EST) on 2/21/2022 with Unit 2 in Mode 1 at 68 percent power, the reactor was manually tripped due to lowering water level in the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were not affected. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non- emergency notification per 10 CFR 50.72(b)(2)(iv)(B). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."

  • * * UPDATE ON 3/23/22 AT 1643 EDT FROM CHRIS MCDUFFIE TO TOM KENDZIA * * *

The following information was provided by the licensee via phone and email: On 2/21/2022, Unit 2 was in Mode 1 increasing reactor power following startup from a forced outage. At 2205 (EST) with Unit 2 at 68 percent power, a feedwater control valve failed to properly control feedwater flow to the 2A Steam Generator and the Integrated Control System initiated an automatic runback. At 2207 (EST), the reactor was manually tripped from 39 percent power due to lowering water level in the 2A Steam Generator. Immediately following the manual reactor trip, an actuation of the Emergency Feedwater System (EFW) occurred. The 2A and 2B Motor Driven Emergency Feedwater (MDEFW) pumps automatically started as designed when the 'low steam generator level' signal was received for the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat was removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were not affected. Unit 2 was restarted on 2/27/2022 following repairs. Due to the Reactor Protection System actuation while critical, this event was reported on 2/22/2022 as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Following further evaluation, it was determined that a valid EFW actuation occurred, therefore this event is now also being reported as a late 8-hour non-emergency notification of a valid actuation of the EFW system in accordance with 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Notified the R2DO (Miller).

ENS 557335 February 2022 04:32:00OconeeNRC Region 2B&W-L-LP

The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At 0357 EST on 2/5/22, Oconee Unit 2 declared an Unusual Event due to a multiple fire alarms and visual observance of a smoke filled room in the West Penetration Room (EAL HU 4.1). Unit 2 automatically tripped and entered Mode 3. There was an indication that a release to the environment potentially occurred. Units 1 and 3 remained at 100% power. The Licensee notified the NRC Resident Inspector, the State, and local authorities. Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), and DHS Nuclear SSA (email).

  • * * UPDATE ON 2/5/22 AT 0748 EST FROM CHUCK CLEMONS TO LLOYD DESOTELL * * *

The following information was provided by the licensee via email: At 0343 EST on February 5th, 2022, with Unit 2 in Mode 1 at 100% power, the reactor automatically tripped due to Reactor Coolant Pump (RCP) Flux/Flow Imbalance caused by the simultaneous trip of all 4 RCPs. The cause of the loss of all RCPs is under investigation. The trip was not complex. There was no inoperable equipment prior to the event that contributed to it. Operations responded and stabilized the plant. Decay heat is being removed by the Reactor Coolant System (RCS) in natural circulation with normal feedwater flow. Due to the Reactor Protection System (RPS) actuation while critical, this event is being reported as a four hour, nonemergency notification per 10 CFR 50.72(b)(2)(iv)(B). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The Licensee notified the State and local authorities. Notified R2DO (Miller)

  • * * UPDATE ON 2/5/22 AT 0815 EST FROM CHUCK CLEMONS TO LLOYD DESOTELL * * *

The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At 0811 EST on 2/5/22, Oconee Unit 2 terminated the notification of unusual event because EAL HU 4.1 criteria were no longer met. Unit 2 remains shutdown in Mode 3. The licensee has notified the State and local authorities and will notify the NRC Resident Inspector. Notified R2DO (Miller), IRD MOC (Gott), NRR EO (Regan), DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).

  • * * UPDATE ON 2/7/22 AT 2342 EST FROM PATRICK GADSBY TO OSSY FONT * * *

The following information was provided by the licensee via email: The follow-up investigation determine that the cause of the trip was determined to be a failed fuse in an undervoltage monitoring circuit for the electrical bus powering the reactor coolant pumps. The trip of the reactor coolant pumps resulted in an automatic reactor trip as designed. The plant responded as expected. There was no fire. The response of the main feedwater system caused an expected increase in temperature in a standby portion of the system which caused the breakdown of the pipe coating producing smoke. There was no release to the environment. The reading of a single instrument was determined to be invalid and other indications supported the conclusion that no release occurred. The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The Licensee notified the NRC Resident Inspector, State and local authorities. A media release was issued on 2/5/22. Notified R2DO (Miller), IRD MOC (Gott), NRR EO (Regan).

ENS 5571326 January 2022 18:49:00OconeeNRC Region 2B&W-L-LP

Licensee provided the following information via email: At 1050 EST on January 26, 2022, it was discovered that the required offsite and the overhead and underground paths of onsite emergency AC power were simultaneously inoperable; therefore this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(A). The overhead path and both required offsite paths were inoperable due to a lockout of the Unit 3 Startup Transformer CT-3. The underground path was made momentarily inoperable as part of aligning an additional offsite power source to Unit 3 to provide defense in depth to a loss of power. The safety function was restored at 1051 EST when the underground path was declared OPERABLE. The offsite power source was restored at 1651 EST. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.

  • * * UPDATE ON 1/26/22 AT 2237 EST FROM GABE SLAUGHTER TO KAREN COTTON * * *

The Licensee updated the 3rd paragraph above as follows via email: The safety function was restored at 1051 EST when the underground path was declared OPERABLE. An offsite power source was restored through Transformer CT-5 within 15 minutes. Startup transformer CT-3 was restored and all offsite and the onsite overhead power source were returned to service by 1651 EST. Investigation of the cause of the CT-3 lockout is in progress. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified of this update.

ENS 5563810 December 2021 03:54:00OconeeNRC Region 2B&W-L-LPAt 0049 EST, on December 10, 2021, with Unit 2 in Mode 1 at 73 percent power, the reactor automatically tripped due to an unknown condition. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being maintained by discharge steam to the main condenser using the turbine bypass valves. Units 1 and 3 are not affected. The cause of the trip is under investigation. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)iv)(B). There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. All rods inserted into the core during the trip. The plant is in its normal shutdown electrical lineup maintaining normal operating pressure and temperature.
ENS 5561429 November 2021 18:47:00Arkansas NuclearNRC Region 4B&W-L-LPOn November 29, 2021 at 1458 CST, Arkansas Nuclear One, Unit 1, (ANO-1) automatically tripped due to high Reactor Coolant System pressure after the 'A' Main Feedwater Pump was manually tripped due to lowering speed. ANO-1 is currently stable in MODE 3 (Hot Standby) maintaining pressure and temperature with the P-75 Auxiliary Feedwater pump and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) for the Reactor Protection System actuation. The NRC Senior Resident Inspector has been notified. Unit 2 was not affected.
ENS 5561227 November 2021 13:16:00OconeeNRC Region 2B&W-L-LPAt 0519 EST on November 27, 2021, with Unit 2 in Mode 5 at zero percent power, an actuation of the Emergency AC Electrical Power System occurred. The reason for the Emergency AC Electrical Power System auto-start was a lockout of the CT-2 transformer; causing a temporary loss of AC power to the main feeder bus. The Keowee Hydroelectric Units 1 and 2 automatically started as designed when a main feeder bus undervoltage signal was received. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the Emergency AC Electrical Power System. Additionally, the temporary loss of AC power resulted in a loss of Decay Heat Removal (DHR) that was restored upon power restoration to the main feeder bus. Therefore, this condition is also being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v) for an event or condition that could have prevented fulfillment of a safety function. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The loss of the CT-2 transformer is under investigation. Main feeder bus power was restored within a minute so no plant heat up occurred as a result of the loss of the decay heat removal system.
ENS 5552315 October 2021 08:52:00OconeeNRC Region 2B&W-L-LPAt 1727 (EDT) on October 14, 2021, it was determined that a licensed operator failed a test specified by the Fitness-For-Duty (FFD) testing program. The individual's authorization for site access has been terminated. The NRC Resident Inspector has been notified.
ENS 5545510 September 2021 14:45:00Three Mile IslandNRC Region 1B&W-L-LPThis is a four-hour notification, non-emergency for a notification of another government agency. This event is being reported under 10 CFR 50.72(b)(2)(xi) and 10 CFR 72.75(b)(2). At 1055 EDT on 9/10/21, an employee of a site contractor that was performing work under a contract and in possession of the immediate area where the work was being performed, was involved in a material handling accident in the owner controlled area at Three Mile Island. Londonderry Township EMS and Fire responded to render assistance to the individual. Upon arrival to the site, medical personnel declared the individual deceased. The fatality was work related and the individual was outside of the Radiological Controlled Area.
ENS 5513814 March 2021 18:05:00Arkansas NuclearNRC Region 4B&W-L-LPOn March 14, 2021, at 1315 CDT, Arkansas Nuclear One, Unit 1(ANO-1) was manually tripped due to degraded voltage and momentary loss of the A-2, non-vital 4160 V Bus in accordance with Abnormal Operating Procedure. All control rods fully inserted. Degraded voltage of the A-2 non-vital 4160 V Bus resulted in de-energizing the A-4 vital 4160 V Bus. Emergency Diesel Generator No. 2, K-4B, started automatically and is currently powering the A-4 vital 4160 V Bus. All other Vital and Non-Vital Buses transferred power automatically to the Startup Transformer No. 1. Offsite power remains energized and available for ANO-1. All other systems responded as designed. The loss of the A-2 Non-Vital Bus is still under investigation. ANO-1 is currently stable in MODE 3 (Hot Standby), maintaining pressure and temperature with Main Feedwater pumps and steaming to the Condenser. There are no indications of a radiological release on either unit as a result of this event. This report satisfies the reporting criteria of both 10 CFR 50.72(b)(2)(iv)(B) for the Reactor Protection System actuation and 10 CFR 50.72(b)(3)(iv)(A) for the actuation of the Emergency Diesel Generator. The Licensee has notified the NRC Senior Resident Inspector.
ENS 5495419 October 2020 07:20:00Arkansas NuclearNRC Region 4CE
B&W-L-LP

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

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

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

ENS 5339610 May 2018 17:03:00OconeeNRC Region 2B&W-L-LP

Unit 3 experienced a loss of AC power while in Mode 6. Power was regained automatically from Keowee via the underground path. Decay heat removal has been restored. Spent fuel cooling has been restored. Emergency procedures (are) in progress. The Licensee notified the senior NRC resident inspector, State of South Carolina and local authorities. The total loss of 4160 volt AC power was for approximately 30 seconds. The unit is refueled and reactor reassembly complete up to bolting on the reactor head. There was no effect on Units 1 and 2. Notified DHS SWO, FEMA Ops Center, FEMA NWC, DHS NICC, and NuclearSSA

  • * * UPDATE FROM SCOTT HAWKESWORTH TO HOWIE CROUCH AT 0554 EDT ON 5/11/18 * * *

At 0530 EDT, Oconee terminated the notification of unusual event on Unit 3. The basis for termination was that offsite power was restored and the plant is now in its normal shutdown electrical lineup. The licensee has notified Oconee and Pickens counties and will be notifying the NRC Resident Inspector. Notified R2DO (Ehrhardt), NRR EO (Miller), IRD MOC (Gott), DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email) and NuclearSSA (email).

ENS 5332913 April 2018 06:07:00OconeeNRC Region 2B&W-L-LPOn 4/13/2018 at 0227 (EDT), the Oconee Unit 1 Reactor was manually tripped from 24 percent power due to the inability to control main feedwater flow through the Main Feedwater Control Valves using the Integrated Control System. Due to the RPS actuation while critical, this event is being reported as a 4-hour Non-Emergency per 10 CFR 50.72(b)(2)(iv)(B). Following the reactor trip, multiple Main Steam Relief Valves failed to reseat at the expected pressure. Using procedure guidance, Main Steam Pressure was lowered by 115 psig, resulting in the closing of all Main Steam Relief Valves. All other post-trip conditions are normal and all other systems performed as expected. Unit 1 is currently in Mode 3 and stable. Decay heat is being removed by the steam generators discharging steam to the main condenser using the turbine bypass valves. Units 2 and 3 are not affected by the Unit 1 reactor trip. The licensee notified the NRC Resident Inspector.
ENS 5332311 April 2018 09:09:00Three Mile IslandNRC Region 1B&W-L-LPOn April 11, 2018, a hydrazine spill resulted in measurable hydrazine levels released at the station outfall to the Susquehanna River over an approximately 16 minute time period. The hydrazine levels exceeded the station NPDES (National Pollutant Discharge Elimination System) permit effluent limitations. The Industrial Waste Treatment system release to the river was secured and no further hydrazine was released to the river. The concentrations released did not threaten the downstream users or the environment. Pennsylvania Department of Environmental Protection was notified of the NPDES non-compliance on April 11, 2018 at 0542 EDT. Pursuant to 10 CFR 50.72(b)(2)(xi), this notification satisfies the requirement to notify the NRC of the occurrence of any event or situation related to the health and safety of the public or onsite personnel, or protection of the environment, for which notification to other government agencies has been made. The NRC Resident Inspector has been notified.
ENS 531066 December 2017 12:42:00Three Mile IslandNRC Region 1B&W-L-LPOn December 6, 2017, during evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornado generated missiles, Three Mile Island Nuclear Station identified a non-conforming condition in the plant design such that specific TS equipment is considered to not be adequately protected from tornado generated missiles. A tornado could generate a missile that could strike the emergency diesel generator (EDG) fuel oil supply tank (DFT) vent stack. This could result in crimping of the stack, which could affect the ability of the DFT to perform its design function if such a tornado would occur. 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)(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 mitigate the consequences of an accident. This condition is being addressed in accordance with NRC enforcement guidance provided in EGM 15-002 and DSS-ISG-2016-01. Compensatory measures have been implemented in accordance with these documents. The NRC Resident Inspector has been informed of this notification.
ENS 529579 September 2017 11:50:00Crystal RiverNRC Region 1B&W-L-LPCrystal River Unit 3 is currently undergoing decommissioning and is permanently shut down. The licensee entered their adverse weather procedure EM-220D based on a Hurricane Warning affecting the site within 36 hours. All applicable sections of EM-220D are complete or in progress. No fuel movement activities are in progress. All equipment including Emergency Diesel Generators (EDGS) is available to perform required spent fuel cooling. The licensee will inform the NRC Region I Office.
ENS 529475 September 2017 17:16:00Three Mile IslandNRC Region 1B&W-L-LPOn September 5, 2017 at 1111 EDT, with the reactor at 100 percent core thermal power and steady state conditions, plant personnel identified that both doors of the emergency personnel airlock of the equipment hatch were open simultaneously due to failure of the interlock. Personnel were at both the outside and inside doors, personnel heard air movement through the air lock. Immediate action was taken to close the inner containment personnel airlock door and it was verified closed. Both doors of the emergency personnel airlock of the equipment hatch were open for less than one minute. There was no radioactive release as a result of the event. The cause of the interlock failure is under investigation. This condition requires an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(ii)(A), the condition of the nuclear power plant, including its principal safety barriers (primary containment), being seriously degraded. This condition is also reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material. The NRC Resident Inspector has been notified.
ENS 5292725 August 2017 14:42:00Three Mile IslandNRC Region 1B&W-L-LPOn August 24, 2017 a malfunction internal to the River Water Chemistry Control System resulted in measurable free available chlorine levels over a one-hour period at the station outfall to the Susquehanna River. The chlorine levels exceeded the station NPDES (National Pollutant Discharge Elimination System) permit effluent limitations. The River Water Chemistry Control System was shutdown until the condition is corrected. The concentrations released did not threaten the downstream users or the environment. Pennsylvania Department of Environmental Protection was notified of the NPDES non-compliance on August 25, 2017 at 1115 (EDT). Pursuant to 10 CFR 50.72(b)(2)(xi), this notification satisfies the requirement to notify the NRC of the occurrence of any event or situation related to the health and safety of the public or onsite personnel, or protection of the environment, for which notification to the other government agencies has been made. The NRC Resident Inspector has been notified. Notified DOE, EPA, USDA, HHS, and FEMA.
ENS 5287024 July 2017 19:25:00OconeeNRC Region 2B&W-L-LPAt 1638 (EDT) on 7/24/2017, Oconee Unit 3 experienced an automatic reactor trip due to a load rejection when the generator output breakers both tripped open unexpectedly while 525kV switchyard maintenance was being performed. The trip was uncomplicated with all systems responding normally post-trip. Due to the RPS (Reactor Protection System) actuation while critical, this event is being reported as a 4-hour non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). The plant responded normally to the reactor trip, and there was no impact on the health and safety of the public or plant personnel. Operations responded using the Emergency Operating Procedure and stabilized Unit 3 in MODE 3. The NRC Senior Resident Inspector has been notified. Decay heat is removed by discharging steam to the main condenser using the turbine bypass valves. Unit 1 and 2 are not affected.
ENS 5281217 June 2017 00:32:00OconeeNRC Region 2B&W-L-LPKeowee Hydro Units (KHU) 1 and 2 were both declared inoperable at 1635 (EDT) on 6-16-17 due to discovery of breaker 1GSC-1 (KHU-1) in the intermediate position, and breaker 2GSC-1 (KHU-2) in the open position. Keowee Hydro Units are required to be operable per TS (Technical Specification) 3.8.1 (AC Sources - Operating), TS 3.8.2 (AC Sources - Shutdown), and TS 3.7.10 (Protected Service Water, applies only to KHU aligned to the Overhead Power Path). All Tech Spec required conditions were entered, and all required actions completed. Both Standby Buses were energized from a Lee Combustion Turbine via an isolated power path at 1715 (EDT) on 6-16-17 in accordance with TS 3.8.1 Condition (I), Required Action (I.1). It has been determined by station personnel that a loss of safety function did occur between 1635 (EDT) (when the Keowee Hydro Units were declared inoperable) and 1715 (EDT) (when the Standby Buses were energized from a Lee Combustion Turbine via an isolated power path). Investigation has determined the cause of breakers 1GSC-1 and 2GSC-1 being out of their required closed position to be inadvertent bumping while performing station work activities. Breakers 1GSC-1 and 2GSC-1 have been reclosed, and both Keowee Hydro Units have been declared operable as of 2351 (EDT) on 6-16-17. The licensee notified the NRC Resident Inspector.
ENS 5276723 May 2017 11:34:00Three Mile IslandNRC Region 1B&W-L-LPOn March 24, 2017, at 1425 EDT, while performing Engineered Safeguards Actuation System (ESAS) quarterly High Pressure Injection/Low Pressure Injection Logic and Component testing, an unintended test signal was generated when a test switch was moved to the OFF position but went slightly past this position and engaged contacts for the Test no. 1 position. When examined, the test switch was found to be degraded which allowed the switch to move past the center position and engage the test no. 1 contacts. This resulted In a partial actuation of 'B'- train ESAS components. It also resulted in an injection to the reactor coolant system (RCS). The test signal was immediately removed by operators and the inadvertently started equipment secured. The plant was operating at 100% power when the event occurred. There were no valid signals or plant conditions present to warrant the safety system actuation. The 'B' Emergency Diesel Generator rolled on air start but did not get up to full speed. Decay Heat Removal Pump 'B' started and the Decay Heat Removal Injection valve 4B opened, Make-Up Pump 'C' started, Make-Up Pump suction valve 14B opened, Make-Up pump discharge valves 16C and 16D opened, Spent Fuel Pump 1B tripped off, Air Handling Fan 18 tripped off and Air Handling Fan 1C trip tripped off. These components properly functioned from the inadvertent test signal and were secured prior to any adverse impact to plant operation. There was a small injection of borated water into the RCS. The plant remained stable at 100% power operation. Pursuant to 10 CFR 50.73(a)(1) the following information is provided as a sixty (60) day telephone notification to the NRC. This notification, reported under 50.73(a)(2)(iv)(A), is being provided in lieu of the submittal of a written LER to report a condition that resulted in an invalid partial actuation of the 'B' train of the Engineered Safeguards Actuation System (ESAS) as it was not part of a pre-planned sequence. The Licensee notified the NRC Resident Inspector.
ENS 5271026 April 2017 14:49:00Arkansas NuclearNRC Region 4CE
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 5248612 January 2017 18:25:00OconeeNRC Region 2B&W-L-LPA non-licensed supervisor has been found in violation of the Duke Energy Fitness for Duty Policy during a random fitness for duty test. The individual's access to the plant has been suspended. The licensee has notified the NRC Senior Resident Inspector.
ENS 5244117 December 2016 05:43:00Arkansas NuclearNRC Region 4B&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.

  • * * UPDATE ON 2/7/17 AT 1528 EST FROM BUCHANON DICKSON TO DONG PARK * * *

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 524157 December 2016 23:39:00Three Mile IslandNRC Region 1B&W-L-LPWhile TMI (Three Mile Island) Unit 1 was in a hot shutdown condition, leakage was identified coming from an RCS (reactor coolant system) pressure boundary on a welded connection on the 'A' Reactor Coolant Pump. The leakage is unisolable from the RCS and is less than 0.5 gpm. Planned actions are to cooldown Unit 1 to cold shutdown conditions in order to repair the leakage. The licensee will be notifying the Pennsylvania Emergency Management Agency and has notified the NRC Resident Inspector.
ENS 5227130 September 2016 04:01:00Arkansas NuclearNRC Region 4B&W-L-LPAt 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 5224215 September 2016 11:18:00Arkansas NuclearNRC Region 4B&W-L-LPDuring 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 5223411 September 2016 17:44:00Arkansas NuclearNRC Region 4B&W-L-LPDuring 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 5219524 August 2016 12:15:00Arkansas NuclearNRC Region 4B&W-L-LPDuring 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 5209718 July 2016 21:41:00Three Mile IslandNRC Region 1B&W-L-LPAt 1600 EDT, testing of the Everbridge ERO (Emergency Response Organization) notification system identified the system was not able to notify all ERO individuals. This constitutes a loss of offsite communications capability. The issue was reported resolved by the vendor and site testing has verified resolution as of 2130. This event is reportable under 10 CFR 50.72(b)(3)(xiii) as a loss of communications capability. The NRC Resident Inspector has been notified. Some of the ERO personnel did not receive a test page. The requirement is to have all ERO personnel receive the page within ten minutes. Compensatory measures were instituted while the system was not functional.
ENS 5204928 June 2016 17:50:00Three Mile IslandNRC Region 1B&W-L-LP

At 1055 (EDT) on 06/28/16 a gas void was found during the monthly surveillance inspection located in the common suction line to the High Pressure Injection / Makeup (HPI / MU) pumps. At 1150 on 06/28/16 the HPI suction line cross-connect valves were closed to isolate and separate the 'A' & 'B' Trains of HPI. The 'A' train of HPI was declared degraded and initiated a 72 hour LCO (Limiting Condition of Operation) under TS (Technical Specification) 3.3.2. Investigation and analysis by Engineering determined that the size of the void did not meet the acceptance criteria for system operability. Due to the size of the void and location at time of discovery, both trains of HPI were determined to be inoperable until the suction cross connect valves were closed. This condition is reportable under 10 CFR 50.72(b)(3)(v)(D) as a Condition That Could Have Prevented Fulfillment of a Safety Function to mitigate the consequences of an accident. The void is being vented to restore a water-solid condition. The last successful surveillance was conducted on 05/31/16. The cause of the void is being investigated. The NRC Resident Inspector has been informed.

  • * * RETRACTION FROM CRAIG SMITH TO DANIEL MILLS AT 1056 EDT ON 08/22/16 * * *

Following the 8-hour 10 CFR 50.72 notification made on 06/28/16 (EN 52049), further engineering analysis determined that the as-found void size was insufficient to cause the high pressure injection pumps to become inoperable or unable to fulfill their safety function. The cause for the void continues to be under investigation including the development of actions to prevent recurrence. Void checks are being performed at an increased frequency until cause is determined, and actions to prevent recurrence are in place. As determined through analysis, both trains of HPl were operable and available such that the safety function was never lost. Therefore, this event notification is being retracted as it is not reportable pursuant to 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector. Notified R1DO (Dimitriadis).

ENS 5194923 May 2016 15:36:00Arkansas NuclearNRC Region 4CE
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 5189129 April 2016 10:48:00Arkansas NuclearNRC Region 4CE
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 5180819 March 2016 22:51:00Arkansas NuclearNRC Region 4CE
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.

  • * * UPDATE AT 0044 EDT ON 3/22/2016 FROM KEITH LEDBETTER TO MARK ABRAMOVITZ * * *

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 5178510 March 2016 09:44:00Arkansas NuclearNRC Region 4CE
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 517706 March 2016 16:09:00OconeeNRC Region 2B&W-L-LP

At 1512 EST, a fire/explosion occurred in the Unit 1 Main Transformer which resulted in a reactor trip. At 1520 EST, the licensee declared a Notification of Unusual Event. Offsite assistance was requested. At 1633 EST, smoke and flame were no longer visible. Fire brigade personnel were applying additional foam to prevent a re-flash. No personnel injuries occurred. Offsite assistance was requested with three local fire departments responding. All rods inserted on the trip. Steam generator feed is by the normal path. The plant is in its normal shutdown electrical lineup. The licensee has notified state and local authorities and the NRC Resident Inspector. Notified DHS SWO, FEMA, and DHS NICC. Notified FEMA NWS and Nuclear SSA via email.

  • * * UPDATE FROM DAVID HALE TO HOWIE CROUCH AT 1711 EST ON 03/06/16 * * *

At 1658 EST, the licensee declared an Alert based on EAL Alert A.1. The cause of entry was that the fire damaged an overhead power line that supplies emergency power to all three units at Oconee. Offsite power is still available to all units. At 1708 EST, the fire is declared out. The licensee has notified the NRC Resident Inspector. Notified DHS SWO, FEMA, DHS NICC, USDA, HHS, DOE, and EPA. Notified FEMA NWS, FDA and Nuclear SSA via email.

  • * * UPDATE FROM DAVID HALE TO HOWIE CROUCH AT 1805 EST ON 03/06/16 * * *

The licensee made notification of the RPS actuation as a result of the transformer fault. The licensee has notified the NRC Resident Inspector. Notified R2DO (Sykes).

  • * * UPDATE FROM DAVID HALE TO HOWIE CROUCH AT 2026 EST ON 03/06/16 * * *

At 2016 EST, the licensee terminated all emergency declarations. The licensee has notified the NRC Resident Inspector. Notified R2DO (Sykes), IRD (Gott), NRR EO (Morris), DHS SWO, FEMA, DHS NICC, USDA, HHS, DOE, and EPA. Notified FEMA NWS, FDA and Nuclear SSA via email.

ENS 517114 February 2016 18:50:00Arkansas NuclearNRC Region 4CE
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 5169529 January 2016 15:06:00Three Mile IslandNRC Region 1B&W-L-LPOn December 1, 2015, at 2119 EST, with Unit 1 in power operation mode, during a planned maintenance activity, an invalid Heat Sink Protection System (HSPS) actuation occurred. At the time of the event, electrical maintenance technicians were verifying a HSPS relay contact state using an electrical test meter. The contact was being verified open by recording both voltage and resistance readings across the contact. The technicians first measured voltage. No voltage was found, indicating the relay contact was open, as expected. The technicians then measured for resistance across the open contact. Test meters have lower circuit impedance when measuring resistance as opposed to voltage, which can result in electrically bridging across open contacts. When the meter was installed across the open contact to obtain the resistance reading, the HSPS actuation circuit logic was completed and the inadvertent HSPS actuation occurred. The HSPS actuation resulted in the steam driven Emergency Feedwater (EFW) pump automatically starting and control valves receiving actuation set point signals. There was no emergency feed water injection into the steam generators. At the time of the inadvertent HSPS actuation, steam generator operating levels were above the HSPS actuation setpoint. The specific train and system that actuated was the Heat Sink Protection System, Emergency Feedwater System Actuation on Loss of All Reactor Coolant Pumps (RCP) Train A. The HSPS Loss of all RCP Train A actuation was complete. The EFW valves and EFW steam driven pump started and functioned successfully. This is reported under 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of HSPS Loss of all RCP Train A and in accordance with 10 CFR 50.73(a)(1), this notification of the invalid actuation is provided in lieu of a written LER. The Licensee notified the NRC Resident Inspector.
ENS 5160715 December 2015 10:24:00Arkansas NuclearNRC Region 4B&W-L-LPThis 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 5154317 November 2015 12:11:00Arkansas NuclearNRC Region 4CE
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.

  • * * UPDATE FROM STEVE KIRSCHBERGER TO VINCE KLCO ON 11/18/15 AT 1940 EST * * *

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 514555 October 2015 21:47:00Three Mile IslandNRC Region 1B&W-L-LP

At 2115 (EDT) on 10/05/15, an Alert was declared due to a fire in the Auxiliary building affecting DC-P-1A (Decay closed cooling pump 1A) and A-Train safety equipment. The fire is out. The licensee reported the fire was extinguished at approximately 2201 EDT. The fire did not hamper operations personnel responding to the fire. Offsite fire assistance was requested. The NRC Resident Inspector will be notified. The licensee notified the York Haven Power Station, PEMA (Pennsylvania Emergency Management Agency), and the counties of Cumberland, Lebanon, Lancaster, York, and Dauphin. Notified DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email).

  • * * UPDATE AT 0015 EDT ON 10/06/15 FROM JAMES CREIGHTON TO S. SANDIN * * *

The licensee is terminating the Alert at 0009 EDT on 10/06/15 based on the following: At 2115 (EDT) on 10/05/15, an Alert (HA3) was declared due to a fire in the Decay Closed Cooling Water Pump '1A' motor and breaker. The fire was extinguished at 2201 (EDT). Following inspection by electrical maintenance the 'P' 480V bus was re-energized at 2305 (EDT) and restoration of previously running loads is in progress. Station (TMI) is in a 72-hour LCO for repairs to the Decay Closed Cooling Water Pump '1A' (DC-P-1A). TMI (Three Mile Island) is terminating the event based upon the above information. The licensee notified the York Haven Power Station, PEMA (Pennsylvania Emergency Management Agency), and the counties of Cumberland, Lebanon, Lancaster, York, and Dauphin. The licensee will issue a press release. The licensee informed the NRC Resident Inspector. Notified R1DO (Bickett), NRR (Howe) and IRD (Gott). Notified DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email).

ENS 5134024 August 2015 11:36:00Arkansas NuclearNRC Region 4CE
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 5126827 July 2015 16:31:00OconeeNRC Region 2B&W-L-LPAt approximately 0956 EDT on July 27, 2015, Oconee Nuclear Station Unit 2 experienced a valid actuation of the Emergency Feedwater System (EFW). At the time of the event, Unit 2 was in Mode 1 at approximately 17% power and increasing with preparations in progress for placing the main turbine on line during a unit startup. The (EFW) actuation was due to a low level on the 2B steam generator, which resulted from failure of 2B Main Feedwater Block Valve 2FDW-40 to automatically open upon demand. All systems operated as expected with no problems observed. Unit 2 is currently stable at approximately 16% power while troubleshooting valve 2FDW-40 (and the 2B Steam Generator level stable at the normal operating level). Units 1 and 3 were unaffected and remain on line and stable at 100% power. Public health and safety were not impacted by this event. This event is being reported as an 8 hour non-emergency in accordance with 10 CPR 50.72(b)(3)(iv) for a valid actuation of the Emergency Feedwater System. The NRC Resident Inspector has been notified. Corrective Action: Troubleshooting of valve 2FDW-40 is on-going.
ENS 5118427 June 2015 06:40:00Arkansas NuclearNRC Region 4CE
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.

  • * * UPDATE ON 6/28/15 AT 1552 EDT FROM KENYON MCNEAILL TO DONG PARK * * *

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 510291 May 2015 16:14:00Arkansas NuclearNRC Region 4CE
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.