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 Start dateReport dateSiteReporting criterionSystemEvent description
ENS 5697417 February 2024 13:37:00Brunswick10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Core Isolation Cooling
Primary containment
The following information was provided by the licensee via email and phone call: At 0837 EST, on 02/17/2024, during a refueling outage at 0 percent power while performing local leak rate testing (LLRT) on the reactor core isolation cooling (RCIC) isolation valves, which is part of the containment boundary, it was determined that the Unit 1 primary containment leakage rate did not meet 10 CFR 50 Appendix J requirements specified in Technical Specification 5.5.12. 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 5695911 February 2024 15:11:00Hatch10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedFeedwater
Primary containment
The following information was provided by the licensee via email: At 1011 EST on 02/11/2024, during a refueling outage at 0 percent power, while performing local leakage rate testing (LLRT) of the feedwater check valves (part of the containment boundary), it was determined that the Unit 1 primary containment leakage rate did not meet 10 CFR 50 Appendix J requirements specified in Technical Specification 5.5.12. 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 569579 February 2024 18:22:00Peach Bottom10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionService water
Reactor Protection System

The following information was provided by the licensee via email: On 2/9/24 at 1322 EST, it was determined that the unit was in an unanalyzed condition. A review of DC feeder circuit protection schemes identified a circuit for the fuel pool cooling system is uncoordinated due to inadequate fuse sizing. This results in a concern that postulated fire damage in one area could cause a short circuit without adequate protection, leading to the unavailability of equipment credited for in 10 CFR 50 Appendix R, Fire Safe Shutdown. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). The postulated event affects the following fire zones: fire areas 6S and 6N (within the Unit 2 reactor building). Compensatory actions for affected fire areas have been implemented. An extent of condition review is being performed. The NRC Senior Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Fire watches have been established in the affected areas. These will be maintained until the protection scheme is revised.

  • * * UPDATE ON 03/08/24 FROM PAUL BOKUS TO TOM HERRITY * * *

The following updated information was provided by the licensee via email and phone call: On 03/08/24 at 1418, extent of condition reviews identified circuit(s) in the Units 2 and 3 Reactor Protection Systems (RPS) which are also uncoordinated due to improper fuse sizing. These circuits are not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects the following fire areas: 32, 33, 38 and 39 (Units 2 and 3 Switchgear Rooms). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Arner)

  • * * UPDATE ON 3/13/2024 AT 1538 FROM TROY RALSTON TO SAM COLVARD * * *

On March 13, 2024, at 1350 EDT, extent of condition reviews identified a circuit in the Unit 2 reactor protection system (RPS) which is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50, Appendix R, Fire Safe Shutdown, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 57 (Switchgear Corridor, common to Units 2 and 3). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. Additionally, it was previously reported that fire area 6N contained a circuit which was not bounded by the Fire Safe Shutdown analysis; however, after further review it has been determined that compliance is maintained in this fire area and is therefore retracted from the scope of this report. The NRC Senior Resident Inspector has been notified. Notified R1DO (Jackson)

  • * * UPDATE ON 3/21/2024 AT 1525 FROM PAUL BOKUS TO IAN HOWARD * * *

The following information was provided by the licensee via email: On 03/21/24 at 1211, extent of condition reviews identified an annunciator circuit for the Unit 3 emergency service water (ESW) and high pressure service water (HPSW) pump structure heating and ventilation panel that is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 47 (Unit 3 pump structure for `B' ESW and `3A'-`3D' HPSW pumps) and the yard fire area (Manhole 026D). In order to restore immediate compliance, the cable has been de-energized to eliminate the possibility of the event of concern. This circuit will remain de-energized or other measures will be implemented until the condition is permanently resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Ford)

ENS 5692818 January 2024 20:04:00Columbia10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Service water
Residual Heat Removal
Spray Pond

The following information was provided by the licensee via email: On January 18, 2024, at 0030 PST, diesel generator 2 (DG2) was shut down following a monthly surveillance run. Subsequently, a leak was discovered in the DG2 building. Service water pump '1B' was secured at 0117, effectively stopping the leak. The leak was determined to be service water coming from a diesel generator mixed air cooling coil. Service water system 'B' and DG2 were subsequently declared inoperable at 0135. After discussion with engineering, it was identified that the amount of service water leakage from the cooling coil was assumed to be greater than the leakage allowed by the calculation to assure adequate water in the ultimate heat sink to meet the required mission time of 30 days. At 1204, it was determined that entry into Technical Specification 3.7.1 condition D was warranted since the assumed leakage from the cooling coil could exceed the calculated allowed value. At 1238, the control power fuses for service water pump '1B' were removed. DG2 and service water system 'B' were declared unavailable, and the technical specification condition for the inoperable ultimate heat sink was exited. With the control power fuses removed, the pump is kept from auto starting, effectively preventing the leak and ensuring the safety function of the ultimate heat sink is maintained while the cooling coil is repaired or replaced. Due to the leakage assumed greater than the calculated allowable value this condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition and per 10 CFR 50.72(b)(3)(v)(B) as an event or condition that could have prevented fulfillment of the safety function of structures or systems that are needed to remove residual heat. There was no impact to the health and safety of the public. The NRC Resident has been notified.

  • * * RETRACTION ON 3/18/24 AT 1923 FROM VALERIE LAGEN TO KAREN COTTON * * *

The following information was provided by the licensee via email: On January 18, 2024 at 2138 EST, Columbia Generating Station notified the NRC under 10 CFR 50.72(b)(3)(ii)(B) of an unanalyzed condition on the available capacity of the ultimate heat sink (UHS) and under 10 CFR 50.72(b)(3)(v)(B) of an event or condition that could have prevented fulfillment of the safety function of structures or systems needed to remove residual heat. On January 18, 2024, following monthly surveillance of the diesel generator DG2, a DG2 room cooler flow alarm was received at 0115. A leak was discovered in the diesel mixed air (DMA) air handler unit. Service Water Pump '1B' was secured and the leakage was stopped at 0117. The service water system 'B' and diesel generator system 'B' were declared inoperable at 0135. The leak was assumed to be greater than that allowed to ensure adequate water in the UHS required to meet the 30-day mission time, and the UHS was declared inoperable at 1204. Control power fuses for the service water pump '1B' were removed to fully eliminate the leakage path from the cooler, and the UHS was declared operable at 1238. Following the event, engineering performed an analysis based on the size and location of the leak, and concluded it would have taken 1.4 days to deplete the available excess water in the UHS to below the minimum technical specification required water level of the spray pond. Operations were able to secure the service water subsystem of the UHS prior to exceeding the volumetric margins in the spray ponds to ensure the 30-day mission time was met. The condition did not represent a safety significant unanalyzed condition nor a loss of safety function. The NRC Resident Inspector has been notified. Notified R4DO (Gepford).

ENS 569123 January 2024 17:57:00Saint Lucie10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded
Reactor Coolant System

At 1257 EST on January 3, 2024, it was determined that a class 1 system barrier had a through wall flaw with leakage. The leakage renders both trains of high pressure safety injection inoperable. The unit is being cooled down to cold shutdown to comply with technical specifications. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officer Report Guidance: At the time of the discovery, the unit was shutdown in mode 3. The unit was experiencing signs of reactor coolant system leakage and a shutdown was initiated in order to search for possible sources. The unit is currently cooling down and proceeding to mode 5, where the safety function is not required.

  • * *UPDATE AT 1257 EST ON 02/12/24 FROM B. MURRELL TO T. HERRITY***

The purpose of this notification update is to retract a portion of a previous report, made on 1/03/2024 at 1257 EST (EN 56912). Notification of the event to the NRC was initially made as a result of declaring both trains of unit 2 high pressure safety injection system inoperable due to reactor coolant barrier through wall leak on the vent line for the 2A2 safety injection tank. Subsequent to the initial report, Florida Power and Light has concluded that the through wall leak rate was insignificant, and therefore the safety injection system's safety-related function was maintained. Therefore, this portion of the event is not considered a safety system functional failure and is not reportable to the NRC pursuant 10 CFR 50.72(3)(v)(D). This update does not affect the original 10 CFR 50.72(b)(3)(ii)(A) report for the degraded condition related to the reactor coolant barrier through wall leak. The NRC Resident Inspector has been notified. Notified R2DO (Miller).

ENS 5691028 December 2023 16:29:00Watts Bar10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionThe following information was provided by the licensee via email: Plant alignment caused an unanalyzed condition regarding unit 1 and unit 2 Appendix R procedures. (Watts Bar Nuclear) (WBN) unit 1 and unit 2 Appendix R procedures require manual operator action times including (volume control tank) (VCT) isolation. They are calculated with an assumed hydrogen cover gas constant at 20 psig. This is to preclude hydrogen ingestion into the charging pumps with an operator action time of 70 minutes. Due to recent lower hydrogen concentration in the (reactor coolant system) (RCS), (unit 2) VCT hydrogen regulator set point was increased to 28 psig. This increased pressure set point invalidated the initial assumptions made in the Appendix R calculations for manual operator action times. WBN unit 1 VCT hydrogen regulator was also verified high out of band at 22 psig. WBN has restored unit 1 and unit 2 VCT hydrogen regulators to the required specification. The NRC Resident Inspector has been notified of this condition.
ENS 5689316 December 2023 01:45:00Saint Lucie10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded
Reactor Coolant System

At 2045 EST on December 15, 2023, it was determined that the reactor coolant system barrier had a through wall flaw with leakage. The leakage is minor in nature and unquantifiable. The leakage is coming from the welded connection of a vent valve for safety injection tank 2A2 outlet valve rendering both trains of high-pressure safety injection inoperable. The unit is being cooled down to cold shutdown to comply with technical specifications. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A) and 10 CFR 50.72(b)(3)(v)(D). 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 unit was heating up after a maintenance outage. The leak was discovered during mode 3 walkdown.

  • * *UPDATE AT 1254 EST ON 02/12/24 FROM B. MURRELL TO T. HERRITY***

The purpose of this notification update is to retract a portion of a previous report, made on 12/16/2023 at 0404 EST (EN 56893). Notification of the event to the NRC was initially made as a result of declaring both trains of unit 2 high pressure safety injection system inoperable due to reactor coolant barrier through wall leak on the vent line for the 2A2 safety injection tank. Subsequent to the initial report, Florida Power and Light has concluded that the through wall leak rate was insignificant, and therefore the safety injection system's safety-related function was maintained. Therefore, this portion of the event is not considered a safety system functional failure and is not reportable to the NRC pursuant 10 CFR 50.72(3)(v)(D). This update does not affect the original 10 CFR 50.72(b)(3)(ii)(A) report for the degraded condition related to the reactor coolant barrier through wall leak. The NRC Resident Inspector has been notified. Notified R2DO (Miller).

ENS 5684910 November 2023 21:45:00Waterford10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition

The following information was provided by the licensee via email: At 1545 CST on November 10, 2023, personnel at Waterford Steam Electric Station Unit 3 determined that 19 conduits in the engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition meets the criteria involving an unanalyzed condition that significantly affects plant safety. The plant is currently defueled. Decay heat is being removed by normal spent fuel cooling system operations. ESFAS is not required to be operable in the current plant mode. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. There was no impact to the health and safety of the public or plant personnel. The NRC Region 4 Branch Chief (Dixon) has been notified.

  • * * RETRACTION ON 1/8/2024 AT 1222 EST FROM PETER RAMON TO ERNEST WEST * * *

On November 10, 2023, Waterford Steam Electric Station Unit 3 reported in EN 56849 that 19 conduits in engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition met the criteria involving an unanalyzed condition that significantly affects plant safety. Waterford 3 has determined that the ESFAS auxiliary relay cabinets A and B jumper conduits do not require fire seals based on review of an engineering specification that specifies the size and length of conduits which require fire seals to be installed. None of the nineteen affected conduits meet the size and length criteria that would necessitate installation of a fire seal. Based on this, the condition described in EN 56849 is not considered to be an unanalyzed condition that significantly affects plant safety as described in 10 CFR 50.72(b)(3)(ii)(B) and therefore is not reportable. The licensee notified the NRC Resident Inspector. Notified R4DO (Gaddy)

ENS 568345 November 2023 16:33:00Waterford10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedSteam GeneratorThe following information was provided by the licensee via email: At 1033 CST on November 5, 2023, while in a refueling outage, it was determined that Waterford Steam Electric Station, Unit 3, did not meet the performance criteria for steam generator structural integrity in accordance with Technical Specification 6.5.9.b.1, Steam Generator Program, due to two tube failures in the number 1 steam generator. The condition was identified during performance of in-situ pressure testing. The affected tubes will be plugged. The plant is currently stable with all fuel in the spent fuel pool. Decay heat is being removed by normal spent fuel cooling system operation. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A) as a degraded condition. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 567859 October 2023 22:07:00Palo Verde10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe following information was provided by the licensee via email: On October 9, 2023, during the Palo Verde Nuclear Generating Station Unit 1 refueling outage, while performing a small nozzle inspection in support of boric acid walkdowns, boric acid leakage was found on the area of the weld of a pressurizer thermowell. At 1507 MST, non-destructive examination of the weld indicated leakage through the reactor coolant pressure boundary. The exam result constitutes welding or material defects in the primary coolant system that are unacceptable under ASME Section XI. 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 567743 October 2023 15:54:00North Anna10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe following information was provided by the licensee via email: At 1154 EDT on 10/03/23, investigation into a boric acid indication was determined to be through a leak on a weld-o-let upstream of a pressurizer level transmitter isolation valve. Unit 2 is currently in MODE 6 with reactor coolant system (RCS) operational leakage limits not applicable. The leak is not quantifiable as it only consists of a small amount of dry boric acid at the location. The failure constitutes welding or material defects in the primary coolant system that are unacceptable under ASME Section XI. Therefore, this is a degraded condition reportable under 10 CFR 50.72(b)(3)(ii)(A). This condition does not affect the health and safety of the public or station employees. The Resident Inspector was notified.
ENS 5668520 August 2023 20:00:00Fermi10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown
10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded
Reactor Coolant SystemThe following information was provided by the licensee via email: On 8/20/2023 at 1600 EDT, during plant walkdowns in the drywell while in mode 3 to identify a cause of increasing unidentified leakage rate, reactor coolant system pressure boundary leakage (approximately 2 gpm) was identified on the reactor recirculation sample line between the reactor recirculation sample line inboard isolation valve (B3100F019) and where the sample line taps off the B reactor recirculation jet pump riser. This requires entry into technical specification 3.4.4 condition C, identification of pressure boundary leakage with a required action to be in mode 3 in 12 hours and mode 4 in 36 hours. At 1630 EDT, a technical specification required shutdown to mode 4, cold shutdown, was initiated. A press release by DTE is anticipated. This event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(i), a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(xi), and an eight-hour, non-emergency notification 10 CFR 50.72(b)(3)(ii)(A) for the degraded condition of the pressure boundary. Investigation into the cause of the reactor coolant system pressure boundary leakage is still ongoing. There was no impact on the health and safety of the public or plant personnel. The NRC resident inspector has been notified.
ENS 5345615 July 2023 10:39:00Arkansas Nuclear10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor
10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded
Reactor 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 566106 July 2023 16:32:00Millstone10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionSteam Generator
Main Steam Isolation Valve
Auxiliary Feedwater
Main Steam Line
The following information was provided by the licensee via email: On July 6, 2023, at 1232 EDT, while operating in Mode 1 at 100 percent power, the supply check valve from the number 2 steam generator to the turbine driven auxiliary feedwater pump was determined during troubleshooting that it is not able to perform its isolation function. This failure would have resulted in the blowdown of both steam generators during a main steam line break in the number 2 steam generator main steam line upstream of the main steam isolation valves until the operators could isolate the faulted steam generator. Previous evaluation has determined that this condition constituted an unanalyzed condition that could impact containment pressure. There was no radioactive release to the environment. The steam line from the steam generator to the turbine driven auxiliary feedwater pump was isolated by use of a motor operated valve in the discharge line of the number 2 steam generator. There was no impact to Unit 3 which remains at 100 percent power. The NRC Senior Resident Inspector was notified. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B) as a condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety.
ENS 5656911 June 2023 05:30:00Beaver Valley10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
The following information was provided by the licensee via email: At 0130 EDT on June 11, 2023, it was discovered that the Beaver Valley Power Station, Unit No. 2 auxiliary building door A-35-5A, credited for tornado missile protection of the primary component cooling water system, was open and unlatched. Upon discovery, the door was shut and latched. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(B). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5654125 May 2023 17:45:00Watts Bar10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionEmergency Diesel GeneratorThe following information was provided by the licensee via phone and email: At 1345 EDT on May 25, 2023, it was determined that a fire barrier for area 737-A1B was not installed, and would render the 2A Emergency Diesel Generator (EDG) not operable in the event of a fire on the Unit 2 side of elevation 737 in the Auxiliary Building. The 2A EDG is the credited power source for fire safe shutdown for a fire located in this area. Without the credited source of power, this places WBN U2 (Watts Bar Nuclear Unit 2) in an unanalyzed condition. A fire watch has been established in the area until the issue is resolved. Therefore, this event is being reported as an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified.
ENS 5649430 April 2023 05:00:00Hope Creek10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded
Primary containmentThe following information was provided by the licensee via email: At 0100 EDT on 04/30/23, it was determined that the primary containment integrity did not meet (Technical Specification) TS 4.6.1.1.d requirement, suppression chamber in compliance with TS 3.6.2.1 due to the inability to establish test conditions for the bypass leakage test in accordance with TS 4.6.2.1.f. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D) & 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 5648522 April 2023 23:42:00Beaver Valley10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe following information was provided by the licensee via email: At 1942 EDT on April 22, 2023, during the Beaver Valley Power Station, Unit No. 2 refueling outage, while performing examinations of the 66 reactor vessel head penetrations, it was determined that one penetration could not be dispositioned as acceptable per ASME Code Section XI. The reactor vessel vent line penetration will require repair prior to returning the vessel head to service. The indication was not through-wall as there was no evidence of leakage based on inspections performed on the top of the reactor vessel head. 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 5647415 April 2023 15:12:00Turkey Point10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedThe following information was provided by the licensee via email: At 1112 EDT on 4/15/23, it was determined that the (reactor coolant system) RCS pressure boundary does not meet ASME Section XI, Table IWB-341 0-1, `Acceptable Standards,' due to through wall leak of the flux mapper seal table guide tube H-6. Corrective actions have been scheduled. `This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A). A follow-up review of the condition revealed that 10 CFR 50.72 notification was applicable within 8 hours of the time of discovery on 04/15/23. The NRC Resident Inspector has been notified.
ENS 564556 April 2023 20:46:00Perry10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionMain Steam Isolation Valve
Main Steam Line
The following information was provided by the licensee via phone and email: On March 4, 2023, it was determined that the main steam line (MSL) local leak rate test results for MSL 'B' were in exceedance of technical specification (TS) surveillance requirement (SR) 3.6.1.3.10 limits. Additionally, the leakage at the outboard main steam isolation valve (MSIV) 'B', was indeterminate due to a gross packing gland leak. An engineering calculation dated April 6, 2023, showed that this leakage, in conjunction with a design basis loss of coolant accident, would result in the radiological dose exceeding Updated Safety Analysis Report limits to the exclusion area boundary, the low population zone, and the control room. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) as a condition that results in the power plant being in an unanalyzed condition that degrades plant safety. Both inboard and outboard 'B' MSIVs have been reworked and are within the TS SR limits. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5643426 March 2023 20:03:00Susquehanna10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedSecondary containmentThe following information was provided by the licensee via email: On 03/26/2023 at 1603 EDT, while performing Appendix J local leak rate testing, it was determined that the Secondary Containment Bypass Leakage (SCBL) limit had been exceeded for Unit 2. During performance of the leak rate test, SE-259-027 for X-9B penetration, it was determined that the combined SCBL limit of 15 standard cubic feet per hour for the as-found minimum pathway was exceeded, as specified in Technical Specification, Surveillance Requirement 3.6.1.3.11. This event is being reported pursuant to 10CFR50.72(b)(3)(ii). The Resident Inspector has been notified.
ENS 5642118 March 2023 18:10:00Nine Mile Point10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedThe following information was provided by the licensee via email: On 3/18/2023 at 1410 EDT, with Nine Mile Point Nuclear Station Unit 1 in a planned refueling outage, the main control room was notified of the results of an automated examination of a dissimilar metal weld on reactor penetration N2E. The results indicate a defect present which cannot be found acceptable under ASME Section XI, IWB-3600. This 8-hour non-emergency report is being made based upon requirements of 10CFR50.72(b)(3)(ii)(A) which states, `The licensee shall notify the NRC ... of the occurrence of ... any event or condition that results in: (A) The condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.' The NRC Senior Resident was informed. A repair plan is being developed.
ENS 5641115 March 2023 03:57:00Browns Ferry10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant System
Main Steam

The following information was provided by the licensee via email: At 2257 (CDT) on 3/14/2023 during the 2R22 refueling outage on Browns Ferry Nuclear Plant Unit 2, it was determined there was RCS boundary leakage from five of eight sensing lines that pass through containment penetrations X-30 and X-34 that did not meet the requirements of Section XI, of the ASME Boiler and Pressure Vessel Code. 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.

  • * * RETRACTION ON 03/28/2023 AT 1059 EST FROM CASEY CARTWRIGHT TO THOMAS HERRITY * * *

The following information was provided by the licensee via email: The purpose of this notification is to retract a previous Event Notification, EN 56411 reported on 3/14/23. Following the initial notification, further analysis of the condition was performed. It was determined that the leaking pipe weld was ASME Section XI Code Class 2 piping which falls under the requirements of ASME Section XI Subsection IWC and not Subsection IWB. Therefore, this condition does not represent a serious degradation of the nuclear power plant, including its principle safety barriers. Based upon the above, the leaks identified on the ASME Section XI Code Class 2 equivalent Main Steam sense lines are not reportable under 10 CFR 50.72(b)(3)(ii). Therefore, the NRC non-emergency 10 CFR 50.72(b)(3)(ii) report was not required and the NRC report 56411 can be retracted and no Licensee Event Report under 10 CFR 50.73(a)(2)(ii) is required to be submitted. Notified R2DO (Miller)

ENS 5637118 February 2023 10:39:00Browns Ferry10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedThe following information was provided by the licensee via email: On February 17, 2023 during the planned U2R22 outage on Browns Ferry Nuclear Plant Unit 2, personnel entered the Unit 2 drywell for leak identification. Personnel discovered a cracked weld on the 2A recirculation pump discharge isolation valve drain line. At 0439 CST on February 18, 2023, following engineering evaluation, this drain line was determined to be ASME Code Class 1 piping. This constitutes an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(ii)(A) - Any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded. The NRC Resident Inspector has been notified.
ENS 5635012 February 2023 13:00:00Beaver Valley10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Control Room Emergency Ventilation

The following information was provided by the licensee via phone call and email: At 0800 on February 12, 2023, it was discovered that both trains of control room emergency ventilation system were simultaneously inoperable due to a safety injection relief valve discharging to a Unit 1 sump. This leakage in conjunction with design basis loss of coolant accident may result in radiological dose exceeding limits to the exclusion area boundary and to the control room, which is common to both Unit 1 and Unit 2. Therefore, this condition is being reported as an eight-hour, nonemergency notification per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(D) as an 'Unanalyzed Condition and a 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.

  • * * RETRACTION FROM ROBERT TAYLOR TO DONALD NORWOOD AT 0530 EDT ON 3/17/2023 * * *

Retraction of EN56350, Control Room Emergency Ventilation System Inoperable: Based on subsequent evaluation, it was determined that the control room emergency ventilation system remained operable due to the maximum measured leak rate being within the bounds of the analysis. The maximum measured leak rate of 32,594 cc/hr from the safety injection system did not challenge the calculated maximum engineered safety features leak rate of 45,600 cc/hr and remained within the current dose analysis limits. As such, this was not an unanalyzed condition and did not prevent the fulfillment of a safety function to mitigate the consequences of an accident. The NRC Resident Inspector has been notified. Notified R1DO (Bickett).

ENS 563427 February 2023 22:38:00Hatch10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedPrimary containmentThe following information was provided by the licensee via email: At 1738 EST on 02/07/2023, while in mode 5 at 0 percent power, it was determined during local leak rate testing (LLRT) that the primary containment leakage rate exceeded the allowable limit defined in 10 CFR 50, Appendix J, 'Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors.' Both primary containment isolation valves in a penetration failed LLRT requirements which represents a failure to maintain primary containment integrity. 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 562573 December 2022 16:00:00Browns Ferry10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedShutdown Cooling
Residual Heat Removal
The following information was provided by the licensee via email: On 12/2/2022 at 2330 (CST) during the planned F311 outage on Browns Ferry Nuclear Plant Unit 3, personnel entered the Unit 3 drywell for leak identification. Personnel discovered a through-wall piping leak on a 0.75 inch test line between the two test line isolation valves. This 0.75 inch test line is located on the residual heat removal (RHR) loop 1 shutdown cooling and RHR return line to the reactor vessel. On 12/3/2022 at 1000 CST, Engineering determined this location is classified as ASME Code Class 1 piping. This constitutes an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(ii)(A) - Any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded. The NRC Resident Inspector has been notified.
ENS 5622114 November 2022 11:30:00Oconee10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe 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 18:33:00Oconee10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe 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 5617623 October 2022 15:30:00Diablo Canyon10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemThe following information was provided by the licensee via email: At 0830 PDT on 10/23/2022, during routine outage inspections on Unit 2, it was determined that the RCS Pressure Boundary did not meet ASME Section XI acceptance criteria on a 2-inch vacuum refill connection line. This event is being reported pursuant to 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 5616515 October 2022 15:59:00Catawba10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedThe following information was provided by the licensee via email: On 10/15/2022 at 1159 (EDT), during the Catawba Nuclear Station Unit 2 refueling outage, it was determined that the results of a planned surface examination Liquid Penetrant test (PT) performed on a previous overlay repair on nozzle number 74 of the reactor vessel closure head (RVCH) did not meet applicable acceptance standards. The examination was being performed to meet the requirements of Relief Request RA-21-0144, 'Proposed Alternative to Use Reactor Vessel Head Penetration Embedded Flaw Repair for Life of Plant'. The penetration required repairs for the discovered indications. The repairs have been completed in accordance with the ASME Code of Record prior to returning the vessel head to service. 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. The original indication that led to the overlay repair was discovered in April 2021, during ultrasonic testing and reported to the NRC and assigned EN55201.
ENS 561537 October 2022 06:19:00Braidwood10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedControl Rod

The following information was provided by the licensee via fax: Control Rod Drive Mechanism (CRDM) penetration 69 degraded. At 0119 (CDT) on October 7, 2022, it was determined that the CRDM penetration 69 was degraded because examination identified unacceptable indications in accordance with ASME Code Case N-729-6. Therefore, 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.

  • * * UPDATE ON 12/13/22 AT 1825 EST FROM KRYSTIAN JARONCZYK TO ADAM KOZIOL * * *

The notification is being corrected to state: At 0119 (CDT) on October 7, 2022, it was determined that the Control Rod Drive Mechanism (CRDM) penetration 69 was degraded because liquid penetrant testing, performed on the seal weld, identified unacceptable indications in accordance with ASME Section III and NRC approved licensee relief request for a previously performed embedded flaw repair. Therefore, 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. Notified R3DO (Ruiz).

ENS 5589613 May 2022 16:11:00Monticello10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Steam Jet Air Ejector
Control Room Envelope
The following information was provided by the licensee via email: On 5/13/22 at 1111 CDT the station entered LCO 3.7.4 Condition B for Control Room Envelope being inoperable. This was due to results from an inspection in the Steam Jet Air Ejector room that identified steam leakage exceeding the leakage rate assumptions made in the Alternate Source Term (AST) dose analysis calculation. Therefore, this is being reported in accordance with 10CFR50.72(b)(3)(ii)(B) for an unanalyzed condition that significantly degrades plant safety and 10CFR50.72(b)(3)(v)(D) for any event or condition that at the time of discovery could have prevented fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. There is no impact to the health and safety of the public. NRC Resident has been notified.
ENS 5585723 April 2022 13:54:00Byron10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded

The following information was provided by the licensee via email: At 0854 (CDT) on April 23, 2022, while performing volumetric inspections required by ASME Code Case N-729-6, a rejectable indication on Reactor Vessel Head Penetration 75 Core Exit Thermocouple (CETC) was identified. The indication is located inboard of the J-groove weld and is OD-initiated (outer diameter - initiated). 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. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The repair is scheduled during the refueling outage.

  • * * UPDATE ON 04/29/22 AT 1112 EDT FROM BRYAN LYKKEBAK TO OSSY FONT * * *

The following information was provided by the licensee via telephone and email: The rejectable indication on Reactor Vessel Head Penetration 75 Core Exit Thermocouple (CETC) initiated on the outside diameter (OD) of the nozzle in an area that was not surface stress mitigated (peened). The indication was found to be acceptable for continued operation under CFR and ASME requirements and will not be repaired during this outage. The licensee notified the NRC Resident Inspector. Notified R3DO (Ziolkowski).

ENS 5570616 January 2022 05:20:00Browns Ferry10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedShutdown CoolingThe following information was provided by the licensee via email: On 1/15/2022 at 2320 (EST) during the planned F108 outage on Browns Ferry Nuclear Plant Unit 1, personnel entered the Unit 1 Drywell for leak identification. Personnel discovered a through-wall piping leak on a 3/4 inch test line upstream of the test valve. This 3/4 inch test line is located on the RHR Shutdown Cooling & RHR Return Line to the reactor vessel and is classified as ASME Code Class 1 Piping. This constitutes an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(ii)(A) - Any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded. The NRC resident has been notified.
ENS 5557614 November 2021 16:50:00Millstone10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionSteam Generator
Main Steam Isolation Valve
Auxiliary Feedwater
Main Steam Line
On November 14, 2021, at 1150 EST, while operating in Mode 1 at 100 percent power, the supply check valve from the Number 2 steam generator to the turbine driven auxiliary feedwater pump was determined during troubleshooting that it is not able to perform its isolation function. This failure would have resulted in the blowdown of both steam generators during a main steam line break in the Number 2 steam generator main steam line upstream of the main steam isolation valves until the operators could isolate the faulted steam generator. Previous evaluation has determined that this condition constituted an unanalyzed condition that could impact containment pressure. There has been no radioactive release to the environment. The steam lines from the steam generators to the turbine driven auxiliary feedwater pump have been isolated by use of a motor operated valve in the discharge line of the Number 2 steam generator. There has been no impact to Unit 3 which remains at 100 percent power. The NRC Senior Resident has been notified. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B) as a condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety.
ENS 5557412 November 2021 21:05:00Turkey Point10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant System

At 1605 EST on 11/12/21, it was determined that the RCS Pressure Boundary does not meet ASME Section XI, Table IWB-341 0-1, 'Acceptable Standards' due to a through wall leak of the Core Exit Thermocouple Nozzle Assembly. Measures have been taken to establish Mode 5 for corrective actions. This event is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(A). The NRC Resident Inspector has been notified.

  • * * RETRACTION ON 3/28/2022 AT 0849 EDT FROM DAVID STOIA TO MIKE STAFFORD * * *

The following information was provided by the licensee via email: On 11/12/2021 EN 55574 reported possible evidence of pressure boundary through-wall leakage observed on a Core Exit Thermocouple (CET) tube. On 3/10/2022, based on laboratory analysis of the affected CET tube section, FPL Engineering determined that there was no pressure boundary through-wall leakage associated with this event. Analysis identified that the leakage likely originated from an adjacent threaded compression fitting on a tubing joint. This condition complies with ASME Section XI requirements and is therefore not reportable. This follow-up NRCOC notification is a retraction of EN 55574. The NRC Resident Inspector has been notified. Notified R2DO (Miller).

ENS 555656 November 2021 15:00:00Millstone10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionSteam Generator
Feedwater
Main Steam Isolation Valve
Auxiliary Feedwater
Main Steam Line
During a Unit 2 refueling outage valve overhaul activity on the steam supply check valve from the number 2 steam generator to the turbine driven auxiliary feedwater pump, 2-MS-4B, the check valve was found with its disc separated from the disc arm. This failure would have resulted in the blowdown of both steam generators during a main steam line break in the steam generator number 2 main steam line upstream of the main steam isolation valves until the operators could isolate the faulted steam generator. On November 6, at approximately 1100 EDT evaluation determined that this condition constituted an unanalyzed condition that could impact containment pressure. There has been no radioactive release to the environment. The valve has been repaired. The check valve in the steam supply from the number 1 steam generator to the turbine driven auxiliary feedwater pump was inspected and found to be satisfactory. There has been no impact to Unit 3 which remains at 100% power. The Senior Resident has been notified. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B) as a condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety.
ENS 555603 November 2021 19:31:00Columbia10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedPrimary containment
Residual Heat Removal
On 11/03/2021 Columbia Generating Station concluded the results for refueling outage 24 (R24) and 25 (R25) Local Leak Rate Testing as-found data was incorrect. At 1231 PDT on November 3rd, 2021 Columbia Generating Station determined the local leak rate tests (LLRT) for the X- 25B containment penetration did not meet Technical Specification requirements for LLRT acceptance criteria. The incorrect LLRT data identified for residual heat removal (RHR) B Suppression Pool Spray containment isolation valve (RHR-V-27B) was from the previous two refueling outages (R24 on 5/22/2019 & R25 on 6/512021) at which time primary containment was not required to be operable. The corrected leakage assigned to the X-25 penetration also resulted in total Type B and C leakage summation exceeding the maximum allowable leakage rate for the primary containment (1.0 La) for R24 and exceeding 0.6La in R25. The valve was flushed and retested satisfactory prior to entering the mode of applicability. 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 5554022 October 2021 05:04:00Beaver Valley10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemAt 0104 EDT on October 22, 2021, during the Beaver Valley Power Station, Unit 2 refueling outage, while performing examinations of the 66 reactor vessel head penetrations, it was determined that two penetrations could not be dispositioned as acceptable per ASME Code Section XI. Penetrations 28 and 40 will require repair prior to returning the vessel head to service. The indications were not through wall and there was no evidence of leakage based on inspections performed on the top of the reactor vessel head. The examinations were being performed to meet the requirements of 10 CFR 50.55a(g)(6)(ii)(D) and ASME Code Case N-729-6 to find potential flaws/indications before they grow to a size that could potentially jeopardize the structural integrity of the reactor vessel head pressure boundary. 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 555064 October 2021 19:33:00Arkansas Nuclear10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedAt 1433 CDT, on October 4, 2021, Arkansas Nuclear One, Unit 2 (ANO-2) completed the analysis related to an indication revealed on head penetration 46 during Reactor Vessel Closure Head inspections. It was determined the indication is not acceptable under ASME code requirements. The indication displays characteristics consistent with primary water stress corrosion cracking. No leak path signal was identified during ultrasonic testing. The plant was in cold shutdown at 0 percent power and in Mode 6 for a refueling outage at the time of discovery. Repair actions will be completed prior to plant startup from the outage. This condition has no impact to the health and safety of the public. This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A) for degradation of a principal safety barrier. This is the only indication that is currently present, however, if additional indications are found, they will also be repaired prior to the plant startup. The NRC Senior Resident Inspector has been notified.
ENS 5545913 September 2021 22:22:00Surry10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionEmergency Diesel GeneratorOn September 13, 2021, at 1822 EDT, an apparent non-compliance with 10 CFR 50, Appendix R, section III.G.2 (separation of redundant fire safe shutdown equipment) was identified. Specifically, it was determined that some Emergency Diesel Generator (EDG) cables may be susceptible to a hot short/spurious operation to the close circuit. A spurious closure of the emergency bus normal supply breakers after the EDG is powering the bus could result in non-synchronous paralleling, EDG overloading, or EDG output breaker tripping due to faulted power cable from normal supply breaker. The spurious closure of the normal supply breakers is not currently addressed in the Appendix R Report or previous Multiple Spurious Operations (MSO) analysis. This condition is associated with the Appendix R safe-shutdown function of the Emergency Power System. The Emergency Power System is considered operable but not fully qualified for its safety-related design function. The following fire areas are impacted: 1) Fire Area 13, Unit 1 Normal Switchgear Room 2) Fire Area 46, Unit 1 Cable Tray Room 3) Fire Area 3, Unit 1 Emergency Switchgear and Relay Room 4) Fire Area 2, Unit 2 Cable Vault and Tunnel Until this condition is analyzed, Surry has implemented mitigating actions in the above fire areas. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B). This is also reportable as a 60-day written report pursuant to 10 CFR 50.73(a)(2)(ii)(B). This event was entered into the licensee's Corrective Action Program as CR (condition report) 1180502. The NRC Resident Inspector has been notified of this event. Mitigating actions include posting fire watches in the affected areas.
ENS 5545712 September 2021 21:28:00North Anna10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant System

On September 12, 2021, at 1728 EDT, with Unit 1 in Mode 5 (Cold Shutdown) while performing inspections of the North Anna Power Station Unit 1 reactor vessel head flange area, a weld leak was identified on the reactor vessel flange leak-off line that connects to the flange between the inner and outer head o-rings. Entered TRM 3.4.6 Condition B for ASME Code Class 1,2, and 3 components. With known leakage past the inner head o-ring, this condition is reported since the fault in the tubing is considered pressure boundary (Reactor Coolant System) leakage. This event is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(A) for any event or condition that results in the condition of the nuclear power plant, including its principle safety barriers, being seriously degraded. The NRC Resident has been notified.

  • * * RETRACTION ON 10/21/21 AT 1153 EDT FROM DENNIS BRIED TO BRIAN P. SMITH * * *

The condition identified in EN 55457, pursuant to 10 CFR 50.72 (b)(3)(ii)(A) has been evaluated, and has been determined not to be Reactor Coolant System (RCS) pressure boundary leakage. As such, the 8-hour report is being retracted, as it is not an event or condition that results in, 'the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.' The leakage was subsequently determined to be in a tubing connection downstream of the reactor vessel inner O-ring. Leakage past a seal or gasket is not considered to be pressure boundary leakage, as defined by Technical Specifications. The NRC Resident Inspector has been notified. Notified R2DO (Miller)

ENS 5542724 August 2021 18:06:00FitzPatrick10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionDuring an extent of condition review of DC control circuits, it was identified there are additional unprotected DC control circuits which are routed between separate Appendix R fire areas. A postulated fire in one area can cause a short circuit and potentially result in secondary fires or cable fires in other fire areas where the cables are routed. The secondary fires or cable failures degrade the degree of separation for redundant safe shutdown trains and are outside the assumptions of the 10 CFR 50 Appendix R Safe Shutdown Analysis. This condition is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(B). Compensatory actions for affected fire areas have been implemented. Design modifications in the affected control circuits are being developed and will be scheduled to correct this condition.
ENS 5537522 July 2021 21:51:00North Anna10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionEmergency Diesel GeneratorOn July 20, 2021, at 1707 EDT, an apparent non-compliance with 10 CFR 50, Appendix R, section III.G.2 (separation of redundant fire safe shutdown equipment) was identified. This issue was initially categorized as not affecting train separation or the ability of the equipment to perform their Design Basis functions. The original concern was entered into the licensee's Corrective Action Program as CR1177199. Subsequently, on July 22, 2021, at 1751 EDT, a further review of the affected control circuits for the Unit 1 and Unit 2 Emergency Diesel Generator (EDG) output breakers and emergency bus feeder breakers identified a concern that breaker position interlocks routed to or through non-safety related components or spaces may affect the ability to provide emergency power on the affected unit due to impacts on the control power circuits during an Appendix R fire associated with a loss of offsite power. The following are the affected fire areas: - Unit 1 and Unit 2 Turbine Buildings - Unit 1 and Unit 2 Cable Spreading Rooms - Unit 1 and Unit 2 Normal (307) Switchgear Rooms This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B). This is also reportable as a 60-day written report pursuant to 10 CFR 50.73(a)(2)(ii)(B). This event was entered into the licensee's Corrective Action Program as CR 1177399. The NRC Resident Inspector has been notified of this event.
ENS 5532122 June 2021 16:08:00Davis Besse10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionAuxiliary FeedwaterAt 1208 (EDT) on 6/22/2021, the high-energy line break door separating Auxiliary Feedwater Train Rooms 1 and 2 was not able to be latched following normal usage. The door was able to be closed, protecting Train 1 equipment from a break in Room 2. However, it is assumed a break in Room 1 would push the unlatched door open and allow high-energy fluids to enter Room 2. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. The door was able to be latched at 1215 (EDT) on 6/22/2021 following repairs to the door latch interlocking mechanism. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). No other equipment was inoperable during this event. The NRC Resident Inspector has been notified.
ENS 5527525 May 2021 21:51:00Catawba10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedPrimary containmentAt 1751 EDT on May 25, 2021, it was determined the local leak rate test (LLRT) for the 2EMF-IN containment penetration did not meet 10 CFR 50 Appendix J requirements for both the inboard and outboard containment isolation valves (2MISV5230 and 2MISV5231). The LLRT was performed during the previous refueling outage at which time primary containment was not required to be operable. The leakage assigned to the penetration also resulted in total leakage exceeding the allowed overall leakage. The valves were repaired and retested satisfactory prior to entering the mode of applicability, 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 552313 May 2021 13:30:00Fermi10 CFR 50.72(b)(3)(ii)(B), Unanalyzed ConditionAt 0930 EDT on 5/3/2021, it was determined that during entries into the Fermi 2 Reactor Building Steam Tunnel (RBST) on 4/17/2021, 4/18/2021, and 4/21/2021 that the door was not controlled according to site procedures. The RBST door is credited as a hazard barrier for various high-energy line break (HELB) scenarios. On the identified dates, the RBST door was left open for brief periods during maintenance related activities in the RBST. This condition is not bounded by existing analyses as the door is assumed to be closed throughout a HELB event. The time period that the door was open was less than one hour in each case, as stay times in the room are inherently limited by industrial and radiological conditions. Individuals remained in the area to close the door if needed, but existing analyses do not address the ability to perform those actions under all HELB scenarios. There is no impact to the health and safety of the public or plant personnel as the door is currently closed and latched and access into the area has been restricted to normal ingress and egress per site procedures, which ensures consistency with existing analyses. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). Investigation into the cause is ongoing. Preliminary review of the extent of this condition identified entries into the RBST on other occasions during the past three years where the conditions may also have not been bounded by existing analyses. The additional occasions where the door may have been held open were on 9/22/2018 (MODE 3), 10/26/2018 (MODE 1 ), 11/2/2018 (MODE 1), and 3/21/2020 (MODE 3). Each of these instances was also less than one hour with the exception of the occurrence beginning on 10/26/2018 which lasted approximately 10 hours to support packing leak repairs on a HPCI (High Pressure Coolant Injection) Outboard Isolation Valve. The licensee notified the NRC Resident Inspector.
ENS 5520121 April 2021 02:30:00Catawba10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemDuring the performance of reactor vessel closure head (RVCH) examinations, at 2230 EDT on April 20, 2021, it was determined that the Unit 2 RVCH penetration nozzle number 74 did not meet the requirements of 10CFR50.55a(g)(6)(ii)(D) and ASME code case N-729-6 . All other RVCH penetration examinations have been completed per 10CFR50.55a(g)(6)(ii)(D) and ASME code case N-729-6 with no other relevant indications identified. The condition of the Unit 2 reactor vessel head penetration nozzle number 74 will be resolved prior to re-installation of the Unit 2 RVCH. This event is being reported as an eight-hour, non-emergency notification per 10CFR50.72(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 551224 March 2021 08:23:00Calvert Cliffs10 CFR 50.72(b)(3)(ii)(A), Seriously DegradedReactor Coolant SystemAt time 0323 (EST) on March 04, 2021, it was determined that the Reactor Coolant System (RCS) pressure boundary did not meet the acceptance criteria under ASME, Section XI IWB-3600, "Analytical Evaluation of Flaws." This condition will be resolved prior to plant start up. 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 has been notified.