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 Entered dateSiteRegionReactor typeSystemScramEvent description
ENS 5357531 August 2018 16:04:00Palo VerdeNRC Region 4Steam GeneratorThe following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) as a Loss of Emergency Preparedness Capabilities at Palo Verde Nuclear Generating Station (PVNGS) Unit 2. On August 31, 2018, at approximately 0544 Mountain Standard Time (MST), the Unit 2 control room experienced an unplanned loss of Steam Generator #1 steam line monitor (RU-139), Channels A and B. This main steam line monitor is used in the PVNGS Emergency Plan to perform dose assessment in the event of a steam generator tube rupture. The NRC Resident Inspectors have been notified."
ENS 5356627 August 2018 13:15:00Grand GulfNRC Region 4On 27 August 2018 at 0918 CDT Grand Gulf Control Room was informed that the onsite credit union silent alarm was actuated. The credit union is located outside of the Secure Owner Controlled Area (SOCA), but is located within the Owner Controlled Area. GGNS (Grand Gulf Nuclear Station) Security entered an elevated security position at 0920 (CDT) and requested assistance from local law enforcement. Claiborne County Sheriff's Department responded to the site. Investigation of the area conducted with the assistance of GGNS Security personnel determined that the cause of the notification was not valid. GGNS Security stood down from the elevated security positon at 0945 (CDT). Pursuant to 10 CFR 50.72(b)(2)(xi), this issue is being reported as any event or situation, related to the health and safety of the public or on-site personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made."
ENS 5356527 August 2018 03:12:00Nine Mile PointNRC Region 1FeedwaterAutomatic Scram

EN Revision Text: AUTOMATIC SCRAM DUE TO A GENERATOR TRIP At 0033 EDT Nine Mile Point Unit 2 experienced an automatic scram on high reactor pressure due to a turbine trip. The cause of the turbine trip was due to a generator trip. All control rods inserted. There were no safety system actuations. The cause of the generator trip is being investigated. This is a 4-Hour report for 10CFR50.72(b)(2)(iv)(B) RPS Actuation. The NRC Resident Inspector has been notified. Decay heat is being removed via the main condenser. Reactor vessel water level is being maintained by the condensate and feedwater systems. The licensee will be notifying the state of New York.

  • * * UPDATE FROM DANIEL CIFONELLI TO HOWIE CROUCH AT 1653 EDT ON 8/28/18 * * *

After further review, the licensee has determined that the cause of automatic scram was due to turbine control valve fast closure as a result of the turbine trip, not high reactor pressure, as originally reported. The licensee has notified the NRC Resident Inspector. Notified R1DO (Lilliendahl).

ENS 5356324 August 2018 15:14:00VogtleNRC Region 2At 1034 (EDT) on August 24, 2018, a contractor supervisor violated the licensee's Fitness-for-Duty (FFD) program by subverting a follow-up Fitness for Duty Test. The contractor's site access has been terminated. The NRC Resident Inspector was notified."
ENS 5356224 August 2018 15:01:00FermiNRC Region 3

At 0745 EDT on August 24, 2018, the Active Seismic Monitoring System failed a planned surveillance test and was declared inoperable. Compensatory measures to provide alternative methods for event classification of a seismic event have been implemented in accordance with the Fermi 2 Emergency Plan procedures. The compensatory measures include the use of information provided by the United States Geological Survey (USGS) to confirm if an earthquake has occurred within a 100 mile radius. The loss of the Active Seismic Monitoring System is reportable to the NRC within 8 hours of discovery in accordance with 10CFR50.72(b)(3)(xiii). No seismic activity has been felt onsite and the USGS recorded no seismic activity in the area. The NRC Resident Inspector bas been notified.

  • * * RETRACTION FROM JEFF GROFF TO VINCE KLCO ON SEPTEMBER 13, 2018 AT 1524 EDT * * *

After further review the Active Seismic Monitoring system was removed from service for planned maintenance for a duration less than 72 hours with appropriate compensatory measures established. Therefore, no major loss of emergency assessment capability occurred. In addition, the surveillance tests were re-performed and the Active Seismic Monitoring System was declared Operable. Therefore, no reportable condition existed and EN 53562 reported on August 24, 20I8 is being retracted. The NRC Resident Inspector has been notified. Notified the R3DO (Hanna).

ENS 5355923 August 2018 12:11:00WaterfordNRC Region 4This is a non-emergency notification from Waterford 3. 10 CFR Part 21 Notification - Defect of Westinghouse 7300 Process Analog Control System circuit cards On August 14, 2018, Entergy Operations, Inc. (Entergy) completed an evaluation of a deviation at Waterford Steam Electric Station, Unit 3 (Waterford 3) which concluded the condition constitutes a defect pursuant to 10 CFR Part 21. The Waterford 3 Site Vice President was notified of the result of this evaluation on August 21, 2018. An interim report stating that an evaluation of this deviation was in progress was submitted to the NRC on July 5, 2018 (Entergy letter W3F1-2018-0040, ADAMS Accession Number ML18186A694). Three Westinghouse 7300 Process Analog Control System (PAC) circuit cards were identified to be failed due to failed hex inverter chips. Some of these cards were installed in applications which support the Ultimate Heat Sink (UHS) at Waterford 3. These PAC cards use Texas Instruments Part Number SN74LS04N, W113 hex inverter chips. The circuit card types of concern are Analog Comparator model number 2838A32G01, Control Board model number 2838A30G011, and Prom Logic model number 2838A33G01. Entergy concluded that this condition could have prevented the UHS from performing its safety function and thus could have created a substantial safety hazard. The NRC Resident Inspector has been notified."
ENS 5355822 August 2018 19:35:00Browns FerryNRC Region 2On 08/22/2018 at 1803 hours CDT, Browns Ferry Nuclear Plant declared an Unusual Event per EAL HU4, a fire potentially degrading the level of safety of the plant. At 1748 CDT Unit 1 received a call reporting smoke coming from the 480V Condensate Demineralizer Panel 3 in the Unit 3 turbine building elevation 557'. At approximately 1803 (CDT), the incident commander on the scene confirmed a fire inside the panel and all three units entered 0-AOI-26-1, Fire Response. The board was subsequently de-energized by operations personnel and the fire was extinguished at 1806 CDT. SM (Shift Manager) exited EAL HU4 and all three units exited 0-AOI-26-1 at 1840 CDT. Fire operations remain on scene to monitor. A team is being assembled for damage assessment and recovery. The fire did not affect any safety systems, no plant transients resulted, and no injuries were reported. This event is reportable within 1 hour IAW 10 CFR 50.72(a)(1)(i). The NRC Resident inspector has been notified. Notified DHS SWO, FEMA Ops, DHS NICC, FEMA NWC (email) and NuclearSSA (email).
ENS 5355722 August 2018 11:23:00Watts BarNRC Region 2Reactor Protection System
Auxiliary Feedwater
Automatic ScramAt 0943 EDT on August 22, 2018, the Watts Bar Unit 2 reactor automatically tripped while operating at 100 percent power. All control and shutdown bank rods inserted properly in response to the automatic reactor trip. All safety systems including Auxiliary Feedwater actuated as designed. The plant is stable with decay heat removal through Auxiliary Feedwater and Steam Dump Systems. The reactor automatically tripped due to a main turbine trip signal. An investigation is in progress. The automatic actuation of the Reactor Protection System (RPS) is being reported as a four-hour report under 10 CFR 50.72 (b)(2)(iv)(B). The expected actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight-hour report under 10 CFR 50.72 (b)(3)(iv)(A). The NRC Senior Resident Inspector has been notified for this event."
ENS 5355622 August 2018 02:00:00LimerickNRC Region 1At 2322 EDT, Limerick Generating Station notified the Pennsylvania DEP (Department of Environmental Protection) that our plant waste water pond (holding pond) overflowed due to heavy rainfall in the area. Plant alignment changes were made and the holding pond stopped overflowing at 0017 EDT. Limerick Generating Station has not determined this release to contain oil, grease, or pollutants hazardous to the public. The licensee notified the NRC Resident Inspector.
ENS 5355421 August 2018 12:25:00FermiNRC Region 3At 08/20/2018 at 1856 (EDT), it was determined that a contract supervisor failed a test specified by the FFD (fitness for duty) testing program. The individual's authorization for site access has been terminated. The NRC Resident Inspector has been notified."
ENS 5355217 August 2018 08:17:00Three Mile IslandNRC Region 1

EN Revision Text: FITNESS-FOR-DUTY TEST POSITIVE FOR NON-LICENSED EMPLOYEE At 1519 EDT on August 16, 2018, Exelon determined a non-licensed employee had a confirmed positive for a controlled substance during a random Fitness-for-Duty test. The employee's unescorted access to the plant has been terminated. The NRC Resident Inspector has been notified.

  • * * UPDATE FROM MICHAEL FITZWATER TO DONALD NORWOOD AT 1310 EST ON 1/8/2019 * * *

The following is a correction to the reason for the Fitness-for-Duty test: At 1519 EDT on August 16, 2018, Exelon determined a non-licensed employee had a confirmed positive for a controlled substance during a follow-up Fitness-for-Duty test. The employee's unescorted access to the plant has been terminated. The NRC Resident Inspector has been notified of this correction. Notified R1DO (Bower) and FFD E-mail group.

ENS 5355116 August 2018 12:08:00ByronNRC Region 3In accordance with 10 CFR 26.719(b)(2)(ii), this notification reports a licensed Operations employee had a confirmed positive for alcohol during a random fitness for duty test. The individual was not in the protected area and not performing licensed duties at the time of discovery. The employee's access to the plant has been suspended. The NRC Resident Inspector has been notified."
ENS 5355014 August 2018 02:18:00Comanche PeakNRC Region 4Steam Generator
Auxiliary Feedwater
Automatic ScramAt 23:58 (Central Daylight Time) Unit 2 Reactor Tripped (automatic reactor trip) due to a Turbine Trip/ Generator Lock Out. All Auxiliary Feedwater Pumps started due to steam generator Lo Lo levels. Unit 2 is being maintained in Hot Standby (Mode 3) in accordance with Integrated Plant Operating Procedure IP0-007B. The Emergency Response Guideline Procedure Network has been exited. Decay heat is being rejected to the Main Condenser via Steam Dump Valves. The cause of the Generator Lockout is currently under investigation. All control rods fully inserted in response to the automatic reactor trip. The licensee notified the NRC resident.
ENS 5354812 August 2018 02:58:00Beaver ValleyNRC Region 1Emergency Diesel Generator

EN Revision Text: TECHNICAL SPECIFICATION REQUIRED SHUTDOWN - LOSS OF 480 VOLTAGE EMERGENCY BUS On 8-12-18 at 0158 EDT, Beaver Valley Unit 2 experienced a loss of 480 Volt 2P Emergency Bus. This resulted in a Loss of Safety Function due to the 2-2 Emergency Diesel Generator (EDG) being Inoperable coincident with the Residual Heat Release Valve (2SVS-HCV104). A Technical Specification shutdown is required per LCO 3.0.3. The Licensee also stated they were in an unanalyzed condition due to the EDG and Residual Heat Release Valve being inoperable at the same time. The Licensee is shutting down to Mode 5 (Cold Shutdown). The Licensee is notifying the Resident Inspector. The Licensee will be making a Press Release about the unplanned shutdown.

  • * * UPDATE ON 08/16/2018 AT 1424 EDT FROM BLASE BARTKO TO KEN MOTT * * *

On 8-12-18 at 0158 (EDT) Beaver Valley Unit 2 experienced a loss of 480 Volt 2P Emergency Bus. Per operational guidance, this was determined to be a Loss of Safety Function due to the Unit 2 Emergency Diesel Generator (EDG) being INOPERABLE coincident with the Residual Heat Release Valve (2SVS-HCV104) 10 CFR 50.72(b)(3)(v)(B) and (D). This was also reported as an Unanalyzed Condition 10 CFR 50.72(b)(3)(ii)(b). No Press Release was performed for this event. The NRC Resident Inspector was notified. At 0410 (EDT) a Technical Specification Shutdown was commenced 10 CFR 50.72(b)(2)(i). At 2011 (EDT) the 480 Volt 2P Emergency Bus was restored and energized. Further evaluation of the event has determined that this event was not an Unanalyzed Condition and did not result in a Loss of Safety Function. The classifications of Unanalyzed Condition and Loss of Safety Function are being retracted. The accuracy of the existing guidance relative to Safety Function has been entered in the Corrective Action Program and interim actions have been taken to provide accurate guidance. Notified R1DO (Young) via email.

ENS 5354610 August 2018 23:13:00Prairie IslandNRC Region 3Emergency Diesel Generator

On 8/10/2018 at 1445 (CDT) both trains of Cooling Water (Cooling Water Pumps for Emergency Diesel Generators) were declared INOPERABLE and both units entered (Technical Specification) (TS) 3.0.3 due to corroded jacket cooling water plugs for (the) 12 and 22 cooling water pump motors; therefore this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). At 1543 (CDT), 08/10/2018 the 121 Cooling Water pump was aligned to the "A" Cooling Water train and the TS 3.0.3 condition was exited for both units. (After restoring train A cooling water the site entered a seven day limiting condition for operations, TS 3.7.8 for one inoperable cooling water pump.) There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.

  • * * RETRACTION ON 09/29/2018 AT 2128 EDT FROM BRIAN JOHNSON TO OSSY FONT * * *

Testing and forensic analysis performed subsequent to the notification has determined the as-found condition would not have impacted either diesel-driven pumps' ability to start, run, and meet flow/pressure requirements to perform their required safety function. Therefore, EN# 53546 is being retracted. The NRC Resident Inspector has been notified of the Event Notification retraction. Notified R3DO (Kozak).

ENS 535387 August 2018 14:45:00VogtleNRC Region 2At 0909 (EDT) on August 7, 2018, Southern Nuclear Operating Company (SNC) determined a contractor supervisor confirmed positive for alcohol during a random Fitness-for-Duty (FFD) test. The employee's unescorted access to the plant has been suspended. The NRC Resident Inspector has been notified."
ENS 535373 August 2018 14:10:00FermiNRC Region 3High Pressure Coolant Injection
Emergency Equipment Cooling Water
At 0940 EDT on August 3, 2018, the Division 2 Mechanical Draft Cooling Tower (MDCT) fans were declared inoperable due to failure of the over speed fan brake inverter. The brakes prevent fan over speed from a design basis tornado. The MDCT fans are required to support operability of the Ultimate Heat Sink (UHS). The UHS is required to support operability of the Division 2 Emergency Equipment Cooling Water (EECW) system. The EECW system cools various safety related components, including the High Pressure Coolant Injection (HPCI) system room cooler. An unplanned HPCI inoperability occurred based on a loss of the HPCI Room Cooler. Investigation into why the Division 2 MDCT fan over speed brake inverter failed is in progress. This report is being made pursuant to 10CFR50.72(b)(3)(v)(D) based on an unplanned HPCI inoperability. The NRC Resident Inspector has been notified."
ENS 535332 August 2018 13:09:00MillstoneNRC Region 1The following was received via telephone and email notification from Millstone Power Station: Millstone Power Station Unit 3, identified that the underground pipe to the Condensate Surge Tank had leaked greater than 100 gallons of water that included trace amounts of tritium to the ground. The effected piping is inside the protected area and has been isolated and drained. No tritium has been detected in any monitoring wells outside of the Protected Area. There is no threat to employees or the public or impact to drinking water. The Connecticut Department of Energy and Environmental Protection, and the towns of Waterford and East Lyme were notified at approximately 1300 (EDT) on August 2, 2018. The licensee notified the NRC Resident Inspector.
ENS 5352827 July 2018 13:41:00VogtleNRC Region 2A non-licensed contractor supervisor had a confirmed positive for alcohol during a random fitness-for-duty (FFD) test. The employee's unescorted access to the plant has been suspended. The licensee notified the NRC Resident Inspector.
ENS 5352224 July 2018 00:57:00Palo VerdeNRC Region 4Steam GeneratorThe following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS (Emergency Notification System) or under the reporting requirements of 10CFR50.73. This event is being reported pursuant to 10CFR50.72(b)(3)(xiii) as a Loss of Emergency Preparedness Capabilities at Palo Verde Nuclear Generating Station (PVNGS) Unit 2. On July 23, 2018, at approximately 1631 Mountain Standard Time (MST), the Unit 2 control room experienced an unplanned loss of Steam Generator #1 steam line monitor (RU-139), channels A and B. This monitor is used to assess dose projections for Main Steam line exhaust while in Modes 1-4 and is used in the PVNGS Emergency Plan to perform classification of Initiating Conditions 'RS1' and' RG1' and Emergency Action Levels (EALs) 'RS1.2' and 'RG1.2'. The PVNGS Emergency Plan does have two additional EALs that can be assessed for each Initiating Condition. The loss of this monitor constitutes a reportable loss of emergency assessment capability. The NRC Resident Inspector has been informed of this condition."
ENS 5351719 July 2018 12:36:00VogtleNRC Region 2At 1300 (EDT) on July 18, 2018, a contractor supervisor violated the licensee's Fitness-for-Duty (FFD) program by subverting the Fitness for Duty process. The contractor's site access has been terminated. The NRC Resident Inspector was notified."
ENS 5351518 July 2018 19:27:00VogtleNRC Region 2A contractor supervisor tested positive for alcohol during an access upgrade fitness-for-duty test. The employee's access to the facility has been suspended. The licensee has notified the NRC Resident Inspector.
ENS 5351117 July 2018 17:01:00VogtleNRC Region 2At 1338 (EDT) on July 17, 2018, Southern Nuclear Operating Company (SNC) determined a contractor supervisor confirmed positive for a controlled substance during a random Fitness-for-Duty (FFD) test. The employee's unescorted access to the plant has been suspended. The Resident Inspector has been notified."
ENS 5350011 July 2018 03:58:00Duane ArnoldNRC Region 3On July 11, 2018, as part of pre-planned maintenance, the site meteorological tower will be removed from service. The tower will be out of service for approximately 11 days. As a result, this is reportable under 10CFR 50.72 (b)(3)(xiii). During the time the data is not available from the meteorological tower; compensatory measures will be in place to obtain the data from the National Weather Service if necessary. The (NRC) Resident Inspector has been notified."
ENS 534999 July 2018 20:05:00VogtleNRC Region 2At 1515 (EDT) on July 9, 2018, Southern Nuclear Operating Company (SNC) determined a contractor supervisor confirmed positive for a controlled substance during a for cause Fitness-for-Duty (FFD) test. The employee's unescorted access to the plant has been suspended. The NRC Resident Inspector has been notified."
ENS 534989 July 2018 18:23:00McGuireNRC Region 2On July 9, 2018, at 1155 hours (EDT), while testing the TSC Ventilation System, an equipment malfunction occurred that resulted in an unplanned loss of TSC ventilation functionality/habitability for greater than seventy-five minutes. If an emergency had been declared requiring TSC activation during this period, the TSC would have been staffed and activated using existing emergency planning procedures. If relocation of the TSC had been necessary, the Emergency Coordinator would have relocated the TSC staff to an alternate location in accordance with applicable site procedures. The TSC ventilation system has been placed in an interim configuration that restored functionality and habitability. Additional maintenance is planned to promptly resolve the malfunctioning equipment. This is an eight-hour, non-emergency notification for a loss of Emergency Assessment Capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the equipment malfunction affected the functionality of an emergency response facility. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The equipment malfunction (a failed solenoid valve) resulted in the loss of the ability to pressurize and filter the air in the TSC.
ENS 534979 July 2018 17:01:00Browns FerryNRC Region 2High Pressure Coolant Injection
Primary Containment Isolation System
On 07/09/2018 at 1111 CDT, Browns Ferry Unit 1 Operators identified U1 High Pressure Cooling Injection system steam supply valves were isolated. After reviewing ICS (Integrated Computer System), Operations determined isolation occurred at 0958 CDT during performance of surveillance testing. The Browns Ferry Nuclear Plant Unit 1 High Pressure Coolant Injection (HPCI) system was declared inoperable at 0958 CDT due to an inadvertent isolation that occurred during testing. During performance of surveillance procedure 1-SR-3.3.6.1.2(3B) HPCI System Steam Supply Low Pressure Functional test, an erroneous signal was induced causing actuation of primary containment isolation system group IV (i.e., HPCI Isolation). Technical Specification 3.5.1, ECCS-Operating, Condition C was entered as a result of the inoperable HPCI system. This constitutes an unplanned HPCI system inoperability and requires an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(v)(D). The erroneous signal was cleared and the HPCI isolation was reset. Upon reset of the isolation signal, the HPCI system was returned to available status. The HPCI system was unavailable for 2 hours and 55 minutes, however the HPCI system remains inoperable. There was no impact to the health and safety of the public or plant personnel as a result of this condition. The NRC Resident Inspector has been notified. A condition report has been entered into the Licensee's Corrective Action Program to capture this event."
ENS 534969 July 2018 16:25:00Duane ArnoldNRC Region 3Secondary containmentAt approximately 1334 CDT on 7/9/18, both doors of a Secondary Containment Airlock were reported to be open simultaneously for a period of less than 3 seconds. The brief time that the doors were simultaneously open constituted an inoperable condition of Secondary Containment. Secondary Containment was immediately restored to operable by closing the airlock doors. Subsequently, the airlock interlock was verified to operate correctly. This event is being reported pursuant of 10 CFR 50.72(b)(3)(v)(C). The Senior NRC Resident Inspector has been notified."
ENS 534937 July 2018 08:29:00Calvert CliffsNRC Region 1At 0242 EDT, the CCNPP (dual unit, single control room) control room supply damper failed shut. This rendered the Unit 1 and Unit 2 control room ventilation inoperable and the appropriate LCOs were entered. At 0249, control room ventilation was restored to service and the appropriate LCOs were exited. This is being reported under 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.
ENS 534916 July 2018 15:36:00ByronNRC Region 3Emergency Diesel Generator
Auxiliary Feedwater
At 1201 (CDT), Station Auxiliary Transformer 242-2 experienced a bushing failure, resulting in a loss of offsite power to Unit 2. The 2A and 2B Diesel Generators started and sequenced loads onto the Unit 2 ESF buses appropriately. All other buses normally powered from the Station Auxiliary Transformers automatically transferred to the Unit Auxiliary Transformers. ESF Bus 241 and 242 Undervoltage Relays actuated to start the Diesel Generators and the 2A Auxiliary Feedwater Pump started on the 2A Diesel Generator sequencer. ESF Battery Charger 212 tripped at the same time, which was an unexpected condition. DC Bus 212 was cross-tied with DC Bus 112. This notification is being made under 10 CFR 50.72(b)3(iv)(A) due to the actuation of both Unit 2 Diesel Generators and the 2A Auxiliary Feedwater Pump. The NRC Senior Resident Inspector has been notified. Currently, offsite power was restored via the Unit 1 Unit Auxiliary Transformer. Both Unit 2 Emergency Diesel Generators have been secured. DC Busses are still cross-tied. The licensee is currently in a 72-hour shutdown action statement for the loss of offsite power and a 7-day action statement for having the Unit 2 DC Bus cross-tied to Unit 1.
ENS 534863 July 2018 23:27:00HarrisNRC Region 2At 1753 on 7/3/2018 it was discovered that both sets of turbine trip solenoids were previously unable to actuate within allowable time frames; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). At the time of discovery, one set of turbine trip solenoids had been restored. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
ENS 534853 July 2018 19:07:00CallawayNRC Region 4Service water
Auxiliary Feedwater

EN Revision Text: DISCOVERY OF AN UNANALYZED CONDITION THAT SIGNIFICANTLY DEGRADES PLANT SAFETY On July 3, 2018, while performing a review of Emergency Operating Procedures, a concern was identified regarding the potential for excessive loss of ultimate heat sink inventory (UHS) through the auxiliary feedwater (AFW) system mini-flow recirculation pathway. This condition would have the potential to prevent the ultimate heat sink from providing an adequate inventory of water for a 30-day mission time.

The normal water supply for the Callaway AFW system is the condensate storage tank (CST). The CST is a non-safety grade component. The safety-grade supply for AFW is the essential service water (ESW) system. The ESW system is supplied by the UHS. The UHS thermal performance analysis accounts for a loss of UHS inventory to the AFW system up until the point of the accident sequence that the AFW pumps would be secured. The analysis did not include an allowance for loss of UHS inventory through the AFW mini-flow recirculation pathway following the AFW pumps being secured. The EOP guidance that secures the AFW pumps does not isolate the mini-flow recirculation pathway.

Initial estimates indicate that loss of UHS inventory through the mini-flow recirculation pathway, if not isolated, would preclude the UHS from completing its 30-day mission time. This potential for depletion of the UHS placed the plant in an unanalyzed condition that significantly degraded safety.

Callaway has issued interim guidance to the on-shift personnel regarding this concern to ensure that the ultimate heat sink water level is maintained at a level that will be adequate to mitigate the potential loss of inventory.

This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for an unanalyzed condition that significantly degrades safety. The NRC Resident Inspectors have been notified of this condition.

  • * * RETRACTION ON 07/31/2018 AT 1430 EDT FROM LEE YOUNG TO ANDREW WAUGH * * *

Event Notification (EN) 53485, made on July 3, 2018, is being retracted because re-evaluation performed subsequent to the notification has demonstrated, based on actual plant equipment and environmental conditions, that the unanalyzed inventory losses previously reported by EN 53485 would not have depleted the UHS inventory to an unacceptable level during its 30-day mission time. The re-evaluation has led to the conclusion that the previously unanalyzed losses of UHS inventory would not have prevented the UHS from performing its specified safety functions and meeting its 30-day mission time requirements. With the UHS capable of performing its specified safety functions and meeting its 30-day mission time requirements, the systems supported by the UHS would have remained capable of performing their specified safety functions. Based on these considerations, it has been determined that the condition reported in EN 53485 did not result in the plant being in an unanalyzed condition that significantly degraded safety. Consequently, the condition did not meet the criteria for an 8-hour notification per 10 CFR 50.72(b)(3)(ii)(B) for an unanalyzed condition that significantly degrades safety. The NRC Resident Inspector has been notified of the Event Notification retraction. Notified R4DO (Gaddy).

ENS 534843 July 2018 12:00:00VogtleNRC Region 2Steam Generator
Auxiliary Feedwater
Manual ScramAt 0954 (EDT) on July 3, 2018, with Unit 1 in Mode 1 at 100 percent power, the reactor was manually tripped due to high steam generator water level. The trip was not complex, with all systems responding normally. Operations stabilized the plant in Mode 3. Decay heat is being removed through the main steam lines through the steam dumps and into the condenser. The expected actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight hour report under 10 CFR 50.72 (b)(3)(iv)(A). Unit 2 was not affected. There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspectors have been notified. All control rods inserted and Unit 1 is in an electrical shutdown lineup. The cause of the high steam generator water level transient is being investigated.
ENS 534811 July 2018 08:24:00PerryNRC Region 3Core SprayOn July 1st, 2018 at 0100 (EDT), a portion of the Division 1 Emergency Core Cooling System (ECCS) Loss Of Coolant Accident (LOCA) initiation logic was declared inoperable due to the discovery of a blown fuse. The fuse was replaced at 0215 on July 1st, 2018 and the Division 1 ECCS LOCA initiation logic was declared operable at 0230 on July 1st, 2018. The blown fuse caused the loss of a portion of the Division 1 ECCS LOCA initiation logic which would have prevented the initiation of the Emergency Closed Cooling (ECC) A system. ECC A and supported systems were declared inoperable. Low Pressure Core Spray (LPCS) was one of the supported systems that were declared inoperable. LPCS is considered a single train safety system. Inoperability of LPCS is considered an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. The blown fuse also caused the loss of a portion of the Division 1 ECCS LOCA initiation logic which would have prevented the automatic isolation of Nuclear Closed Cooling and Instrument Air to the Containment. The loss of Containment isolation capability is considered an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) The NRC Senior Resident Inspector has been notified."
ENS 5347928 June 2018 13:05:00VogtleNRC Region 2At 0902 EDT on June 28, 2018, 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 NRC Resident Inspector has been notified.
ENS 5347728 June 2018 05:37:00Palo VerdeNRC Region 4Steam GeneratorAutomatic ScramThe following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS (Emergency Notification System) or under the reporting requirements of 10 CFR 50.73. On June 27th, 2018 at approximately 2310 Mountain Standard Time (MST), in Palo Verde Unit 3, the #1 Steam Generator Economizer valve started closing. This caused Steam Generator #1 water level to decrease. Both Feed water pumps speed increased to raise Steam Generator level. At approximately 2311 (MST), the B Main Feed water pump tripped resulting in a Reactor Power Cutback. Steam Generator #1 level continued to decrease resulting in an Automatic Reactor Trip on Low Steam Generator #1 water level. All control rods inserted to shut down the Reactor to Mode 3 using Main Feed water and Steam Bypass. Post trip Steam Generator #1 level then increased and at approximately 2316 (MST) a Main Steam Isolation Signal (MSIS) was received on high Steam Generator level. The 'B' Auxiliary Feed water pump was manually started to maintain Steam Generator water levels and Steam Generator pressure was controlled using the Atmospheric Dump Valves (ADVs). Following the reactor trip, all CEAs (Control Element Assemblies) inserted fully into the core. All systems operated as expected. No emergency plan classification was required per the Emergency Plan. Safety related busses remained powered during the event from offsite power and the offsite power grid is stable. No major equipment was inoperable prior to the event that contributed to the event or complicated operator response. Unit 3 is stable and in Mode 3 feeding Steam Generators with Auxiliary Feed water Pump 'B'. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The event did not adversely affect the safe operation of the plant or the health and safety of the public. The NRC Resident Inspector was informed of the Unit 3 reactor trip. Unit 1and Unit 2 were unaffected by the Unit 3 trip.
ENS 5347626 June 2018 23:29:00CooperNRC Region 4Control Room Emergency Filtration System

EN Revision Text: CONTROL ROOM EMERGENCY FILTRATION SYSTEM DECLARED INOPERABLE On June 26, 2018, at 1630 CDT, the Control Room Emergency Filtration System (CREFS) was declared inoperable when Main Control Room Supply Fan SF-C-1B was discovered to have elevated vibrations that brought into question the ability to meet its mission time. CREFS is a single train safety system. Per 10 CFR 50.72(b)(3)(v)(D), an 8 hour report is required due to the fact that at the time of discovery this condition could have prevented the fulfillment of a safety function of an SSC (System Structure or Component) that is required to mitigate the consequences of an accident. The licensee has notified the NRC Senior Resident Inspector.

  • * * RETRACTION FROM THOMAS FORLAND TO VINCE KLCO ON 8/13/18 AT 1024 EDT * * *

The following retraction was received from Cooper Nuclear Station (CNS) via facsimile and phone call: CNS is retracting the 8-hour non-emergency notification made on June 26, 2018 at 1630 CDT (EN# 53476). Subsequent evaluation concluded that overall vibration levels were not at a level that would impact the ability of the Main Control Room Supply Fan SF-C-18 to perform its safety function for its required mission time and the CREFS therefore, was operable. The NRC Senior Resident Inspector has been notified. Notified the R4DO (Deese).

ENS 5347226 June 2018 04:26:00Comanche PeakNRC Region 4Steam GeneratorAt time 0003 (CDT), Main Steamline Radiation Monitor 2-RE-2326 (Main Steam line 2-02) reading spiked and (was) declared non-functional. With this radiation monitor non-functional, all of the emergency action levels for a steam generator tube rupture in steam generator 2-02 could neither be evaluated nor monitored. This unplanned condition is reportable as a loss of assessment capability per 10CFR50.72(b)(3)(xiii). Comanche Peak Nuclear Power Plant (CPNPP) has assurance of steam generator integrity and fuel cladding integrity and there is negligible safety significance to the current condition (with respect to the) public health and safety perspective. Additionally, compensatory measures are in place to assure adequate monitoring capability is available to implement the CPNPP emergency plan in the unlikely event of challenges to the steam generator or fuel cladding. The N16 radiation monitor serves as a backup with alarm function and Radiation Protection technicians have been briefed on taking local readings with a Geiger-Mueller tube on MSL 2-02. Corrective actions are being pursued to restore 2-RE-2326 to functional status. The NRC Resident Inspector has been notified."
ENS 5347125 June 2018 17:58:00Diablo CanyonNRC Region 4At 1029 PDT on June 25, 2018, Pacific Gas and Electric determined 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 NRC Resident Inspector has been notified
ENS 5346922 June 2018 15:12:00VogtleNRC Region 2At 0900 (EDT) on June 22, 2018, a non-licensed supervisory contractor subverted a random Fitness for Duty test. The contractor's site access has been terminated. The NRC Resident Inspector was notified. "
ENS 5346722 June 2018 12:14:00Watts BarNRC Region 2Reactor Protection System
Auxiliary Feedwater
Automatic ScramAt 0841 EDT on June 22, 2018, the Watts Bar Unit 2 reactor automatically tripped while operating at 95% power. All control and shutdown bank rods inserted properly in response to the automatic reactor trip. All safety systems including Auxiliary Feedwater actuated as designed. The plant is stable with decay heat removal through Auxiliary Feedwater and Steam Dump Systems. The reactor automatically tripped due to a main turbine trip. The turbine trip was caused by main generator electrical trip. An investigation is in progress. The automatic actuation of the Reactor Protection System (RPS) is being reported as a four hour report under 10 CFR 50.72 (b)(2)(iv)(B). The expected actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight hour report under 10 CFR 50.72 (b)(3)(iv)(A). The NRC Senior Resident Inspector has been notified for this event. The plant is currently stable at normal operating temperature and pressure. The grid is stable and the plant is in its normal shutdown electrical lineup. Unit 1 was unaffected by the Unit 2 trip.
ENS 5346320 June 2018 17:51:00ClintonNRC Region 3Feedwater
Primary containment
Core Spray
Automatic Depressurization System
On June 20, 2018, at 1145 hours (CDT), during panel walkdown, it was identified that High-Pressure Core Spray (HPCS) injection valve 1E22F004 was in the open position. Valve 1E22F004 is normally closed for containment integrity purposes. Operations personnel verified that the valve was open locally and that the plant computer indicated the valve is in the 'not closed' position. No alarms or status lamps indicated why the valve would be open and there was no valid demand signal. Reactor power, pressure, level, and feedwater parameters remain steady and unchanged, with no indication of HPCS injection having occurred or in progress. A low-water level signal, or a high drywell pressure signal, or manual operation initiates HPCS. When a high-water level in the reactor vessel is detected, HPCS injection is automatically stopped by a signal to close injection valve 1E22F004. With valve 1E22F004 in the open position without a demand signal, closure on a high reactor water level condition was not assured. Therefore, HPCS was declared inoperable. The following Technical Specifications were entered: 3.5.1, Emergency Core Cooling Systems (ECCS) - Operating and 3.6.1.3, Primary Containment Isolation Valves (PCIVs). Subsequently, HPCS injection valve 1E22F004 was observed to be cycling without operator action. The valve was deactivated in the closed position to assure the containment isolation function. The cause of valve 1E22F004 cycling without operator action is under investigation. HPCS is a single train safety system that consists of a single motor-driven pump, a spray sparger in the reactor vessel, and associated piping, valves, controls and instrumentation. HPCS is part of the ECCS network, which also includes Low-Pressure Core Spray, Low-Pressure Coolant Injection, and the Automatic Depressurization system. This event is being reported as an 8-hour non-emergency notification per 10 CFR 50.72(b)(3)(v) as, 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: (A) Shut down the reactor and maintain it in a safe shutdown condition; (B) Remove residual heat; (C) Control the release of radioactive material; or (D) Mitigate the consequences of an accident.' The licensee notified the NRC Resident Inspector.
ENS 5346220 June 2018 11:39:00Browns FerryNRC Region 2On June 20, 2018 at 1003 CDT, the licensee declared a Notification of Unusual Event based on Emergency Action Level (EAL) 6.5.U, toxic gas release on site. The Notification of Unusual Event was terminated at 1025 CDT. The toxic gas release occurred when site personnel were filling a fire suppression carbon dioxide (CO2) tank outside the diesel generator building. The relief valve in the common diesel generator room for Unit 1 and 2 diesel generators inadvertently lifted causing a toxic gas environment by releasing CO2 into the room. The licensee terminated the tank fill stopping the release of CO2, and with the door to the room being opened, the gas cleared in about 20 minutes. The licensee has notified the NRC Resident Inspector. Notified DHS SWO, FEMA Ops, DHS NICC, FEMA NWC (email) and NuclearSSA (email).
ENS 5345916 June 2018 15:56:00Arkansas NuclearNRC Region 4Steam Generator
Feedwater
Reactor Protection System
Main Steam Isolation Valve
Main Turbine
Manual ScramAt 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 5345612 June 2018 22:11:00Arkansas NuclearNRC Region 4Reactor Coolant SystemOn 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 534434 June 2018 14:00:00BraidwoodNRC Region 3Steam Generator
Feedwater
Auxiliary Feedwater
Manual ScramAt 0920 CDT, Braidwood Unit 1 reactor was manually tripped due to lowering steam generator water levels following a trip of the 1C main feedwater pump. The cause of the 1C main feedwater pump trip is unknown at this time and is under investigation. Both trains of Braidwood Unit 1 auxiliary feedwater started automatically following the reactor trip to maintain steam generator water levels. All systems responded as expected. Steam generator power operated relief valves lifted momentarily and reseated as designed in response to the secondary transient due to the reactor trip. The main steam dump valves are in service to the main condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. AC power is being provided by offsite power with the diesel generators in standby and all safety systems available. There is no impact to Unit 2. This report is being made per 10CFR50.72(b)(2)(iv)(B) for a RPS actuation, 4-hr. notification, and per 10CFR50.72(b)(3)(iv)(A) for an automatic actuation of the auxiliary feedwater system, 8-hr. notification. All rods inserted into the core during the trip. Concerning the relief valves momentarily lifting and reseating, there is no known primary-to-secondary leakage. The licensee has notified the NRC Resident Inspector.
ENS 534381 June 2018 14:42:00SalemNRC Region 1Service water
Auxiliary Feedwater

During the period of evaluation of tornado missile vulnerabilities and the potential impacts to technical specification (TS) plant equipment, it was determined that the power cables to a safety related motor control center (MCC) in the service water (SW) intake structure are not adequately protected from tornado generated missiles. During walk downs, it was identified that the installed SW pipe tunnel barrier is not adequate. A tornado could generate missiles capable of striking the power cables and rendering a SW MCC inoperable. These conditions are reportable per 10 CFR 50.72(b)(3)(ii)(B) and per 10 CFR 50.72(b)(3)(v)(D). This condition is being addressed in accordance with NRC enforcement guidance provided in Enforcement Guidance Memorandum (EGM) 15-002, 'Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' Revision 1, and DSS-ISG-2016-01, 'Clarification of Licensee Actions in Receipt of Enforcement Discretion per Enforcement Guidance Memorandum EGM 15-002, Enforcement Discretion for Tornado- Generated Missile Protection Noncompliance,' Revision 1. Compensatory measures have been implemented in accordance with these documents. The NRC Resident Inspector has been notified. The licensee will be notifying the Lower Alloways Creek Township.

  • * * UPDATE ON 6/18/2018 AT 1604 EDT FROM JUSTIN HARGRAVE TO RICHARD SMITH * * *

During subsequent walk downs, PSEG (Public Service Enterprise Group) identified that both the Unit 1 and Unit 2 turbine driven auxiliary feedwater pumps are also not adequately protected from tornado generated missiles. The steam exhaust pipe could be potentially impacted and cause crimping that could reduce steam exhaust flow and pump capacity. EN 53438 is updated to include both Salem units and these additional components. This condition is being addressed in accordance with NRC enforcement guidance provided in enforcement Guidance Memorandum (EGM) 15-002, 'Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' Revision 1, and DSS-ISG-2016-01, 'Clarification of Licensee Actions in Receipt of Enforcement Discretion per Enforcement Guidance Memorandum EGM 15-002, Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' Revision 1. Compensatory measures have been implemented in accordance with these documents." The NRC Resident Inspector has been notified. The licensee will be notifying the Lower Alloways Creek Township. Notified R1DO (Burritt).

ENS 5342927 May 2018 12:42:00FermiNRC Region 3GE-4Primary containment
Reactor Water Cleanup
On May 27, 2018 at 0630 EDT, the Reactor Water Cleanup (RWCU) System Isolation Differential Flow - High function was declared inoperable as a result of indicating downscale. This condition would have prevented the primary containment isolation valves for the RWCU system from automatically isolating on a high differential flow instrumentation signal. At 0753, RWCU was shutdown and the affected penetration flow paths were isolated in accordance with station procedures per Fermi Technical Specifications. The cause of the event is under investigation. There was no radiological release associated with this event. All other RWCU primary containment isolation instrumentation functions remained operable and the associated RWCU system primary containment isolation valves were capable of being remotely closed by the control room operators throughout the event. However, the condition is reportable pursuant to 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified.
ENS 5342827 May 2018 00:40:00MillstoneNRC Region 1CE
Westinghouse PWR 4-Loop
County and state governments were notified due to the spurious actuation of a single emergency notification siren located in New London County in the Town of Lyme. The siren was silenced. If required, alternate notification of the public in the area will be through local Emergency Operations Center route alerting. The NRC Resident Inspector has been notified.
ENS 5342623 May 2018 18:32:00CallawayNRC Region 4Westinghouse PWR 4-LoopOn May 23, 2018 Callaway determined that a violation of one provision of the site's Fitness for Duty (FFD) policy occurred. FFD pre-access testing confirmed a test failure for alcohol. The violation was committed by a non-licensed supervisory employee. The individual did not hold unescorted access to the plant but did perform behavioral observation program (BOP) duties. The BOP qualification has been removed. The NRC Resident Inspector has been notified by the licensee.