Semantic search
| Start date | Report date | Site | Reporting criterion | System | Event description | |
|---|---|---|---|---|---|---|
| ENS 57036 | 19 March 2024 15:30:00 | Browns Ferry | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection | The following information was provided by the licensee via fax or email: While performing a planned high pressure coolant injection (HPCI) system surveillance, an isolation signal was received based upon an exhaust rupture disc high pressure signal. This resulted in an unplanned inoperability of the HPCI system. All systems responded as expected, and the event is under investigation. No other systems were affected by this condition. This event is reportable as an 8-hour non-emergency notification under 10CFR50.72(b)(3)(v) as HPCI is a single train safety system. There was no impact to plant personnel or the public as a result of this condition. The NRC resident has been notified of this condition. | |
| ENS 57041 | 13 March 2024 10:48:00 | Cooper | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection | The following information was provided by the licensee via email and phone: At 0548 CDT on March 13, 2024, during a planned (high pressure coolant injection) HPCI maintenance window, a condition was identified not associated with the planned maintenance which caused HPCI to be inoperable. Specifically, the HPCI auxiliary oil pump start stop pressure switch could not be adjusted into calibration. Further investigation found that the pressure switch was not mounted as designed. Since HPCI is a single train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The condition was corrected prior to HPCI being declared operable on March 15, 2024. The reason for the delay in the event notification beyond 8 hours from the event time was due to not recognizing the need to report the condition while in a planned HPCI maintenance window. The NRC Senior Resident Inspector has been notified. | |
| ENS 57019 | 10 March 2024 08:53:00 | South Texas | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | HVAC Control Room Envelope Containment Spray | The following information was provided by the licensee via email: On 3/9/2024 at 2126 CST, train C essential cooling water was declared inoperable due to a through-wall leak on the discharge vent line. This would also cascade and cause train C essential chilled water to be inoperable. On 3/10/2024 at 0353 CDT, train B essential chilled water was declared inoperable due to chilled water outlet temperature greater than 52 degrees F following startup of essential chiller 12B. Chilled water outlet temperature was adjusted to less than 52 degrees F at 0440 CDT, and train B essential chilled water was declared operable. This condition resulted in the inoperability of two of the three safety trains required for the accident mitigating functions including: high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chilled water. This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident. The licensee notified the NRC Resident Inspector. | |
| ENS 57010 | 5 March 2024 13:20:00 | Comanche Peak | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Service water HVAC | The following information was provided by the licensee via email:
On March 5, 2024, at 0720 CST, the X-02 118V uninterruptible power supply air conditioning (UPS A/C) unit tripped with the associated emergency fan coil units (EFCUs) shut down for planned maintenance in the area. The X-01 UPS A/C unit was declared inoperable upon discovery due to a scheduled outage of support systems (Unit 1 station service water) via the safety function determination process. This placed the site in technical specification 3.7.20 condition A, B, and C to restore the UPS A/C system within one hour. The EFCUs were restarted at 0729 which satisfied condition B and C, and X-01 UPS A/C unit was aligned to Unit 2 cooling water at 0801, exiting condition A. The condition that could have prevented the fulfillment of the safety function lasted for approximately nine minutes. Area temperatures had no notable change based on field observations during the condition. The UPS HVAC system provides temperature control for the safety related UPS and distribution rooms during all normal and accident conditions. The UPS HVAC system consists of (a) a dedicated UPS room EFCU in each safety-related UPS and distribution room, and (b) two electrically independent and redundant A/C trains either of which can support all four safety related UPS and distribution rooms; each train consists of an air conditioning unit, ductwork, dampers, and instrumentation. The NRC Resident Inspector has been notified. | |
| ENS 56989 | 22 February 2024 17:03:00 | Cooper | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling Emergency Core Cooling System | The following information was provided by the licensee via email: At 1103 CST on February 22, 2024, a potential through-wall steam leak was identified on the high pressure coolant injection (HPCI) steam supply 1-inch drain line. As a result, HPCI was declared inoperable. Since HPCI is a single-train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) remain operable. Additional investigation is in progress. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56938 | 29 January 2024 16:05:00 | Grand Gulf | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Core Spray | The following information was provided by the licensee via email: At 1005 CST on January 29, 2024, Grand Gulf Nuclear Station was conducting surveillance testing on the high pressure core spray system. During testing, the 1E22F012 minimum flow valve failed to return to the full closed position. The valve went from full open indication to dual indication. The event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition which could have prevented the fulfillment of a safety function. Troubleshooting is in progress. The NRC Senior Resident has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: All off-site power is available. No other systems are out of service and there are no compensatory measures taken. There is no increase to plant risk. | |
| ENS 56944 | 24 January 2024 01:02:00 | South Texas | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Steam Generator | The following information was provided by the licensee via email: At 1640 CST on February 1, 2024, it was determined that a condition occurred that could have prevented the fulfillment of a safety function due to two of the four steam generator (SG) power-operated relief valves (PORVs) being simultaneously inoperable. In certain accident scenarios, more than two PORVs are needed to mitigate the consequences of an accident; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The first PORV was declared inoperable at 1025 on January 22, 2024, and the safety function is considered to have been lost when the second PORV was declared inoperable at 1902 on January 23, 2024. The safety function was restored at 2234 on January 23, 2024, when the first SG PORV was declared operable. There was no impact to unit 2. 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 plant remained in mode 3 for the duration of the condition. The causes for the two PORVs being inoperable were neither related nor systemic in nature. All SG PORVs have been restored to operation. | |
| ENS 56915 | 5 January 2024 15:40:00 | Davis Besse | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Shield Building | The following information was provided by the licensee via phone and email: At approximately 1111 EST on 01/05/2024, a mechanical penetration room door was discovered unlatched. Based on security badge history, the door was last opened at 1040 EST. The unlatched door resulted in both trains of the station emergency ventilation system being inoperable due to being unable to maintain the shield building negative pressure area. With both trains simultaneously inoperable, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The door was closed and verified latched upon discovery to restore the systems to an operable status. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
The station emergency ventilation system (EVS) was tested with the mechanical penetration room door unlatched. The test results showed that the station EVS attained the required negative pressure in the shield building within the time required by the Technical Specifications. Therefore, the station EVS remained operable with the door unlatched, and this issue did not prevent the system from fulfilling its safety function to control the release of radioactive material and mitigate the consequences of an accident. The NRC Resident Inspector has been notified. Notified R3DO (Orlikowski) | |
| ENS 56912 | 3 January 2024 17:57:00 | Saint Lucie | 10 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.
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 56896 | 18 December 2023 07:23:00 | Hatch | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling Emergency Core Cooling System | The following information was provided by the licensee email: At 0223 EST, on 12/18/2023, while Unit 2 was at 100 percent power in mode 1, the high pressure coolant injection (HPCI) outboard steam isolation valve closed resulting in the HPCI system being declared inoperable. The cause of the outboard steam isolation valve closing is under investigation. HPCI does not have a redundant system, therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The safety function was restored at 0512, on 12/18/23, and HPCI has been declared operable. Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) were operable during this time. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56893 | 16 December 2023 01:45:00 | Saint Lucie | 10 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.
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 56866 | 20 November 2023 15:56:00 | Dresden | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Emergency Core Cooling System | The following information was provided by the licensee via email: At 0956 (CST) on November 20, 2023, accumulated gas was identified in the Dresden Unit 2 high pressure coolant injection (HPCI) system discharge header. As a result, the HPCI system was declared inoperable. Since HPCI is a single-train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The HPCI system was subsequently vented, and the accumulated gas has been removed, restoring the Dresden Unit 2 HPCI system to an operable status. All other emergency core cooling systems remained operable during this time period. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee administratively verified the isolation condenser was operable after declaring HPCI inoperable as required by technical specifications. The licensee stated there was no increase in plant risk. The cause of gas accumulating in the Dresden Unit 2 HPCI discharge header is under investigation, and this issue has been entered into the licensee's corrective action program. | |
| ENS 56861 | 16 November 2023 21:41:00 | South Texas | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Emergency Diesel Generator HVAC Control Room Envelope Containment Spray | The following information was provided by the licensee via phone and email: 11/05/23, 2200 CST: Essential Chiller 'B' train and associated cascading equipment were declared INOPERABLE for planned maintenance. Unit 2 entered the Configuration Risk Management Program as required by Technical Specifications on 11/12/23 at 2200. 11/16/23, 1541: Essential Chiller 'C' train and associated cascading equipment were declared INOPERABLE due to an unexpected material condition causing the Essential Chiller to trip. The most limiting (Limiting Condition of Operability) LCO is 3.7.7, Action c. This condition resulted in the INOPERABILITY of two of the three safety trains required for the accident mitigating function including: High Head Safety Injection, Low Head Safety Injection, Containment Spray, Electrical Auxiliary Building HVAC, Control Room Envelope HVAC, Essential Chilled Water. This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident. A risk analysis was performed for the equipment INOPERABILITY and mitigating actions have been taken per site procedures. All 'A' train equipment remains operable. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The 'B' train Emergency Diesel Generator was also inoperable due to planned maintenance and continues to be inoperable. It was considered in the Configuration Risk Management Program and it was determined this condition could be maintained. LCO 3.7.7, Action c requires reactor shutdown within 72 hours. | |
| ENS 56848 | 10 November 2023 20:13:00 | South Texas | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | HVAC Control Room Envelope Containment Spray | The following information was provided by the licensee via email: On 11/10/23 at 0642 CST, essential chiller 'B' train and cascading equipment was declared inoperable due to chill water temperature exceeding limits. At 1413 CST, essential chiller 'C' train and cascading equipment was declared inoperable due to discharge pressure exceeding limits. This condition resulted in an inoperable condition on two out of the three safety trains for the accident mitigating function including the 'B' and 'C' train high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chill water. All 'A' train equipment remained operable. This was determined to be reportable within 8 hours as required by 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: Plant is in a 72 hour limiting condition for operation per technical specification 3.7.7. Restoration of 'B' train anticipated on 11/11/23 mid day. | |
| ENS 56811 | 22 October 2023 16:49:00 | Cooper | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary containment Reactor Building Ventilation | The following information was provided by the licensee via fax and phone: On October 22, 2023, at 1149 CDT, with the reactor at 100 percent core thermal power and steady state conditions, the Cooper Nuclear Station secondary containment differential pressure exceeded the Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.1.1 limit of -0.25 inches water gauge. The condition existed for approximately 80 seconds until the reactor building ventilation system responded to restore differential pressure to normal. Investigations identified a hinged duct access hatch found open. The hatch was closed and latched, and ventilation system parameters were returned to normal. There were no radiological releases associated with this event. Declaring secondary containment inoperable as a result of not meeting TS SR 3.6.4.1.1 is reportable under 10 CFR 50.72(b)(3)(v)(C) and (D) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material and mitigate the consequences of an accident. The NRC Senior Resident Inspector has been informed. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At the time the licensee notified the NRC Headquarters Operations Officer, the cause of the hinged access duct being open had not been determined. This event has been added to the licensee's corrective action program. | |
| ENS 56644 | 30 July 2023 16:19:00 | Waterford | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: On July 30, 2023 at 1119 CDT, Waterford Steam Electric Station Unit 3 declared the control room envelope inoperable in accordance with technical specification (TS) 3.7.6.1 due to the control room envelope doors failing a door seal smoke test creating a breach in the control room envelope. Operations entered TS 3.7.6.1 Action b. Mitigating actions were implemented and tested satisfactorily by 1215 CDT. There was no impact on the health and safety of the public or plant personnel. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to mitigate the consequences of an accident, due to the control room envelope being inoperable. The NRC Resident Inspector has been notified.
The original operability determination of inoperable was made based on a conservative evaluation that with presence of smoke in-leakage through Door 261 and 262, the CRE boundary could not perform its safety function. A more detailed engineering evaluation was subsequently performed. No maintenance or intrusive testing was performed on the doors after initial test failure. As documented in version 2 operability determination for condition report WF3-2023-14604, the CRE boundary remained intact for the condition identified and was able to fulfill its safety function. The licensee has notified the NRC Resident Inspector. Notified R4DO (Warnick). | ||
| ENS 56637 | 25 July 2023 13:24:00 | Millstone | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Control Room Emergency Ventilation Control Room Envelope | The following information was provided by the licensee via email: At 0924 (EDT) on July 25, 2023, it was discovered that both trains of control room air conditioning system were simultaneously inoperable due to an inoperable control room envelope boundary. The boundary was restored at 0925 (EDT) on July 25, 2023. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. There has been no impact to Unit 3 which remains at 100% power.
The licensee determined in a subsequent engineering evaluation of the conditions that existed at the time, that the access hatch being open did not have an adverse impact upon the control room emergency ventilation system and the control room envelopes boundary's ability to perform their safety function including: Radiation dose to the occupants did not exceed the licensing basis, design basis accident calculated value. Protection of control room occupants from hazardous chemicals and smoke. Therefore, this condition is not reportable and NRC Event EN56637 is being retracted. The basis for this conclusion has been provided to the NRC Resident Inspector. Notified R1DO (Lally) | |
| ENS 56570 | 13 June 2023 03:33:00 | Fermi | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Emergency Diesel Generator Emergency Equipment Cooling Water | The following information was provided by the licensee via email: At 2333 EDT on June 12, 2023, the division 2 Mechanical Draft Cooling Tower (MDCT) Fan `D' was declared inoperable due to a trip of the fan while running in high speed. 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. The cause of MDCT Fan `D' trip is currently unknown with trouble shooting being developed for remediation of the condition. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) based on an unplanned HPCI inoperability. The NRC Senior Resident Inspector has been notified.
The purpose of this notification is to retract a previous event notification (EN) 56570 reported on June 13, 2023, at 0602 EDT. The cause of the fan trip was a failed vibration switch. At 0429 EDT on June 14, 2023, the vibration switch was replaced, the MDCT fan "D" was tested satisfactory for operability, and the UHS, emergency diesel generator 13/14, and MDCT were declared operable. Following the initial EN, further analysis of the condition was performed utilizing a previously performed gothic analysis model (to perform HPCI room heat-up calculations) which bounded this condition. Based on the initial conditions at the time of the indication loss, specifically HPCI room and suppression pool temperature, it was determined that the resulting worst case post-accident room temperature was sufficiently low enough to provide margin to HPCI operability without the room cooler in service for the required mission time. No other concerns were noted during the event. HPCI remained operable and there was no loss of safety function. The fan trip did not involve a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident under 10 CFR 50.72(b)(3)(v)(D). Therefore, the NRC non-emergency 10CFR50.72(b)(3)(v)(D) report was not required and the NRC report 56570 can be retracted, and no licensee event report under 10 CFR 50.73(a)(2)(v)(D) is required to be submitted. The licensee notified the NRC Resident Inspector. Notified R3DO (Nguyen) | |
| ENS 56520 | 16 May 2023 16:27:00 | Wolf Creek | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | The following information was provided by the licensee via phone and email: At 1127 CDT on 5/16/2023, during the reperformance of test procedure 'STS PE-006, Charcoal Adsorber In-Place Leak Test' due to a failure from the previous day, both trains of emergency exhaust were rendered inoperable due to incorrect performance of the procedure. Performers incorrectly de-energized the humidity control heating coil for the unit not under test, rendering it inoperable. This issue was identified and rectified at 1138 CDT on 5/16/2023, exiting the LCO (limiting condition of operation) for both trains inoperable at that time. There was no impact to the health and safety of the public.
The initial failure of the STS PE-006 test was caused by a malfunction of the test equipment which initially injected excessive amounts of tracer gas and caused saturation of the charcoal. Using test equipment sourced from Callaway, and following guidance from the vendor, STS PE-006 test was successfully passed on 5/17/2023. No maintenance or intrusive testing was performed on the unit between initial test failure and satisfactory completion of the test. Because this train of emergency exhaust was not actually inoperable at the time the second train was rendered inoperable due to incorrect procedure performance, there was no loss of safety function. Therefore, this event notification is being retracted. The licensee has notified the NRC Resident Inspector. Notified R4DO (Gepford). | ||
| ENS 56509 | 8 May 2023 07:07:00 | Cooper | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Core Spray | The following information was provided by the licensee via fax: At time 0207 CDT, Cooper Nuclear Station (CNS) entered Technical Specification (Limiting Condition for Operation) LCO 3.0.3 due to declaring core spray subsystems A and B inoperable. This declaration was based on an issue with relays installed from the same manufacturing batch. The ability of the relays to function correctly to annunciate loss of logic power was called into question and they were declared inoperable. The plant has initiated actions to repair/replace affected relays. This event is reportable under 10 CFR 50.72(b)(2)(i) as an initiation of any nuclear plant shutdown required by Technical Specifications. In addition, this event Is reportable under 10 CFR 50.72(b)(3)(v) as a condition that could have prevented the fulfillment of a safety function for the core spray systems. NRC Resident Inspector was notified.
The following information was provided by the licensee via email: Technical Specification LCO 3.0.3 was exited at 0805 CDT on May 8, 2023. A reasonable expectation of operability was developed for the core spray subsystems A and B. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Shutdown was initiated and power was reduced approximately 45 percent. Reactor power is currently at 55 percent at the time of notification. Notified R4DO (Werner) via email.
The following information was provided by the licensee via email: CNS is retracting the 8-hour 10 CFR 50.72(b)(3)(v) non-emergency notification, for a condition that could have prevented the fulfillment of a safety function, made on May 8, 2023, at 0207 CDT (EN# 56509). Subsequent evaluation concluded that the core spray subsystems remained operable in accordance with the Technical Specifications Requirements 3.5.1, ECCS - Operating. As a result of the core spray system remaining operable, no loss of safety function occurred. The NRC Senior Resident Inspector has been notified. Notified R4DO (Werner). | |
| ENS 56494 | 30 April 2023 05:00:00 | Hope Creek | 10 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 containment | The 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 56480 | 18 April 2023 21:30:00 | Comanche Peak | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Emergency Core Cooling System Containment Spray | The following information was provided by the licensee via email: Notification per 10 CFR 50.72 (b)(3)(v)(A) and (v)(D) At time 1630 CDT on 4/18/23, Comanche Peak Unit 1 entered TS (Technical Specification) 3.0.3 for 11 minutes due to declaring Train A component cooling water (CCW) inoperable in conjunction with a Train B centrifugal charging pump (CCP) inoperable for scheduled maintenance. This resulted in an event or condition that could have prevented fulfillment of a safety function, high head injection of the emergency core cooling system. CCP 1-02 and fan cooler were tagged out of service at 0400 CDT on 4/18/23 due to scheduled maintenance activities. Containment spray (CT) pump 1-03 seal oil cooler CCW leak was found by a watchstander at 0930 CDT on 4/18/23. Engineering determined that leakage was CCW from a pipe flange weld after insulation removal and could not (determine) operability and notified control room at 1630 CDT on 4/18/23. This placed unit 1 in a TS 3.0.3 condition from 1630 to 1641 CDT for approximately 11 minutes until CCP 1-02 was restored back to operable status. CCW was declared operable at 1912 after CT pump 1-03 seal oil cooler was isolated. CT pump 1-03 remained inoperable until weld repair completed. Train A CT pump 1-03 declared operable at 1211 CDT 4/19/23. ENS notification should have been made by 0030 CDT on 4/19/23. This report restores compliance. The NRC Resident Inspector has been notified.
The following information was provided by the licensee via phone and email: Although Comanche Peak Unit 1 conservatively entered a limiting condition for operation action statement and performed repairs immediately, further engineering inspection and evaluation concluded that the CCW system was fully able to provide the needed flow to the 1-03 CT pump seal coolers from the time of discovery (0930 CDT) until which time the piping was isolated for repairs. During this period, structural integrity of the joint was maintained, CCW inventory loss remained within acceptable limits, and CCW could perform its intended design and safety functions. Based on this revised operability determination, train A CCW was always operable, and TS 3.0.3 did not apply. Therefore, reportability requirements per 10 CFR 50.72 (b)(3)(v)(A) and (v)(D) did not apply, and a 60 day LER will not be submitted. The licensee notified the NRC Resident Inspector. Notified R4DO (Young) | |
| ENS 56471 | 17 April 2023 07:46:00 | LaSalle | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Core Spray Emergency Core Cooling System | The following information was provided by the licensee via email: At 0246 CDT on April 17, 2023, it was discovered that the single train low pressure core spray system was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). All other emergency core cooling systems remained operable during this time period. 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: LaSalle Unit 1 is in a 7 day limiting condition for operation. | |
| ENS 56458 | 8 April 2023 00:52:00 | Susquehanna | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 2052 EDT on April 7, 2023, during routine system preventative maintenance functional testing, the Unit 1 HPCI turbine stop valve, FV-15612, remained in the intermediate position. This failure resulted in the Unit 1 HPCI system being inoperable. This is being reported as a loss of an entire safety function condition in accordance with 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The Unit 1 HPCI inoperability places Unit 1 in a 14-day Technical Specification (TS) Limiting Condition for Operation (LCO). | ||
| ENS 56429 | 23 March 2023 15:45:00 | Fermi | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via fax: While in Mode 1 at 100 percent power at 1145 EDT on March 23, 2023, it was determined that all mechanical draft cooling Tower (MDCT) fan brakes would not perform their design function during a tornado due to a design flaw with the control system. The MDCT fan brakes are required to prevent fan overspeed from a design basis tornado. The MDCT fans are required to support the operability of the ultimate heat sink (UHS). At the time of discovery, the provisions of LCO 3.0.9 were being utilized for loss of the 'D' MDCT fan brake (barrier loss). When it was identified the condition was a design flaw common to all MDCT fan brakes, the 24-hour allowance for restoration was entered. A design change is currently being implemented to restore MDCT fan brake operability. This condition is reportable per 10 CFR 50.72(b)(3)(v)(A), (B), & (D). The NRC Resident Inspector has been notified. | ||
| ENS 56409 | 14 March 2023 14:00:00 | Susquehanna | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 1000 EDT on March 14, 2023, during valve diagnostic testing, the high pressure core injection (HPCI) lube oil cooling water supply isolation valve did not stroke open. This failure resulted in the Unit 2 HPCI system being inoperable. This is being reported as a loss of an entire safety function condition in accordance with 10CFR50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.
The following information was provided by the licensee via email: The purpose of this notification is to retract event notification (EN) 56409 reported on 03/14/2023. On March 09, 2023, Susquehanna Unit 2 entered a routine high pressure core injection (HPCI) maintenance outage. In support of this system outage, Technical Specification (TS) 3.5.1, Condition D was entered for an inoperable HPCI system. On March 14 as reported in EN 56409, the HPCI lube oil cooling water supply isolation valve did not electrically stroke open following engagement of manual clutch lever. Specifically, to support the maintenance evolution, electricians declutched the valve actuator to move it from the motor/electric operational mode to the manual operational mode as part of planned valve diagnostic data collection. In this testing configuration (i.e., manual operational mode), an attempt to electrically stroke the valve was made, resulting in the valve failure to stroke. Prior to this maintenance evolution, the HPCI lube oil cooling water supply isolation valve was found in the expected full-closed position with the motor/electric operational mode enabled, meaning prior to the HPCI maintenance outage, the affected valve was operating as designed and capable of performing all design functions. The described condition was therefore determined to be the result of the maintenance activity. NUREG-1022, Section 3.2.7, states: 'reports are not required when systems are declared inoperable as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that would have resulted in the system being declared inoperable).' Following completion of investigation and repair, Susquehanna determined that, per NUREG-1022, Section 3.2.7, the event was not reportable. HPCI was declared inoperable as part of a maintenance evolution which was done in accordance with an approved procedure and the TS. The described condition was not a pre-existing condition that would have resulted in the system being declared inoperable prior to the planned maintenance activity. Notified R1DO (Schroeder) | ||
| ENS 56350 | 12 February 2023 13:00:00 | Beaver Valley | 10 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 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 56321 | 24 January 2023 07:21:00 | Browns Ferry | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling | The following information was provided by the licensee via email: At 0121 CST on 01/24/2023, it was discovered that the Unit 1 High Pressure Coolant Injection System (HPCI) was inoperable; therefore, the condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v), as 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. 1-FCV-073-0006B, HPCI Steam Line Condensate Outboard Drain Valve, failed closed during normal plant configuration. This valve is normally open. The HPCI steam line is not being drained with the valve in the current position. The Unit 1 Nuclear Unit Senior Operator entered Unit 1 Technical Specifications LCO 3.5.1 Condition C with required actions C.1 to immediately verify by administrative means that the Reactor Core Isolation Cooling (RCIC) system is operable and C.2 to restore HPCI to operable status in 14 days. RCIC has been verified operable by administrative means. There was no impact to the safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56295 | 4 January 2023 06:48:00 | Fermi | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Emergency Equipment Cooling Water | The following information was provided by the licensee via email: At 0148 EST on January 4, 2023 it was identified that P4400F603B, Division 2 Emergency Equipment Cooling Water (EECW) Supply Isolation Valve, lost position indication. Division 2 EECW System was declared inoperable due to the potential that this valve may not be capable of performing its safety function to automatically isolate the safety related Division 2 EECW system from the non-safety related Reactor Building Closed Cooling Water (RBCCW) system. Because the Division 2 EECW system provides cooling to the High Pressure Coolant Injection (HPCI) room cooler, HPCI was also declared inoperable; therefore, this condition is being reported as an eight-hour, non--emergency notification per 10 CFR 50.72(b)(3)(v)(D). At 0240 EST, position indication was restored and Division 2 EECW and HPCI was returned to operable following inspection of the associated motor control center (MCC) and testing of the associated fuses. The cause of the loss of indication is under investigation. The Senior NRC resident inspector has been notified.
The following retraction was received from the licensee via email: The purpose of this notification is to retract a previous Event Notification, EN 56295, reported on 1/4/2023. Following the initial EN, further analysis of the condition was performed utilizing a gothic analysis model to perform HPCI room heat-up calculations. Based on the initial conditions at the time of the indication loss, specifically HPCI room and Suppression Pool temperature, it was determined that the resulting worst case post-accident room temperature was sufficiently low enough to provide margin to HPCI operability without the room cooler in service for the required mission time. No other concerns were noted during the event. Therefore, HPCI remained operable and there was no loss of safety function. The event did not involve a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident under 10 CFR 50.72(b)(3)(v)(D). Therefore, the NRC non-emergency 10 CFR 50.72(b)(3)(v)(D) report was not required and the NRC report 56295 can be retracted and no Licensee Event Report under 10 CFR 50.73(a)(2)(v)(D) is required to be submitted. The NRC Senior Resident Inspector has been notified. Notified R3DO (Ruiz). | |
| ENS 56241 | 28 November 2022 09:00:00 | Fermi | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Service water High Pressure Coolant Injection Residual Heat Removal Emergency Equipment Cooling Water | The following information was provided by the licensee via email: At 0400 EST on November 28, 2022, during the performance of Division 2 Residual Heat Removal (RHR) cooling tower fan operability and RHR Service Water valve lineup verification, it was reported that the Mechanical Draft Cooling Tower (MDCT) Fan 'B' was making a loud metallic noise. The cause of the metallic noise is unknown at this time. 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 inoperable cooling water to the HPCI room cooler, per LCO 3.0.6. Investigation into the Division 2 MDCT Fan 'B' abnormal noise is in progress. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) based on an unplanned HPCI inoperability. The NRC Resident Inspector has been notified.
The following information was provided by the licensee via email: The purpose of this notification is to retract a previous Event Notification 56241 reported on 11/28/2022. On 11/28/22, an event notification to the NRC was made when mechanical draft cooling tower (MDCT) Fan B was declared inoperable and issued Limited Condition of Operation (LCO) 2022-0428 for Division 2 MDCT Fan B abnormal noise. The MDCT fans are required to support operability of the Ultimate Heat Sink (UHS) (Technical Specification (TS) 3.7.2). The UHS is required to support operability of the Division 2 Emergency Equipment Cooling Water (EECW) system (TS 3.7.2), which cools various safety related components, including the High-Pressure Coolant Injection (HPCI) system room cooler (TS LCO 3.0.6). Subsequent inspection and evaluation determined that the brake noise is expected while fans are running at low speeds. This is supported by plant technical procedure, 24.205.10 `Div. 2 RHR Cooling Tower Fan Operability and RHRSW Valve Line-up Verification' (line item 2.2 in Precautions and Limitations) which states `Chatter from the brakes of the MDCT Fans is expected and no cause for discontinuing the test.' The equipment vendor stated that brake chatter is possible and common given that the internal components are free to move along the splined connections. Internal Operating Experience from experienced station operators and maintenance technicians confirmed that the condition is normal and expected. Both Division 2 MDCTs exhibited the same behavior at low speed and passed surveillance testing satisfactorily. No other concerns were noted during fan operation. Therefore, HPCI remained operable and there was no loss of safety function. The event did not involve a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident under 10 CFR 50.72(b)(3)(v)(D). EN 56241 is retracted and no Licensee Event Report under 10 CFR 50.73(a)(2)(v)(D) is required to be submitted. The NRC Resident Inspector has been notified. Notified R3DO (Stoedter). | |
| ENS 56203 | 4 November 2022 05:06:00 | LaSalle | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 0006 CDT on 11/04/2022, it was discovered that both trains of control room area ventilation air conditioning systems were simultaneously inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). 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: With both trains of control room area ventilation air conditioning systems inoperable, the plant entered a 72 hour limiting condition for operation (LCO). One train had been restored at the time of report which extends the LCO to 30 days. | ||
| ENS 56186 | 28 October 2022 00:50:00 | Harris | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Steam Generator Auxiliary Feedwater | The following information was provided by the licensee via email: At 2050 EDT (on October 27, 2022), with Unit 1 in Mode 3, it was discovered that all auxiliary feedwater pumps were simultaneously inoperable and the capability to supply the 'B' steam generator was not maintained; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The function of the auxiliary feedwater pumps to supply the 'A' steam generator and 'C' steam generator was maintained. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56175 | 23 October 2022 08:05:00 | Vogtle | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Automatic Depressurization System | The following information was provided by the licensee via email: At 0405 EDT on 10/23/2022, with (Vogtle) Unit 3 in Mode 6 and the reactor subcritical for greater than 28 hours, it was discovered that all three required flow paths for the stage four ADS were simultaneously inoperable; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The diverse actuation system was operable for manual stage four ADS during this time period. At 0432 EDT on 10/23/2022, two of the three required flow paths were restored to operable status, which exited the reportable condition. All required flow paths were operable at 0447 EDT. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 56168 | 18 October 2022 19:40:00 | Browns Ferry | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Standby Liquid Control | The following information was provided by the licensee via email: On 10/18/2022 at 1440 CDT, Browns Ferry Unit 3 declared both trains of standby liquid control (SLC) inoperable due to acceptance criteria failure of 3-SI-3.1.7.6, 'Standby Liquid Control System ATWS Equivalency Calculation for Newly Established Pump Flow Rate.' The purpose of this surveillance is to ensure the anticipated transient without scram (ATWS) calculation criteria is met after each pump flow test. Chemistry performed the surveillance following pump flow testing and the requirement for equivalency calculation failed low with a result of less than 1.0. CR 1810303 documents this condition in the corrective action program. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(A), 10 CFR 50.72(b)(3)(v)(C), and 10 CFR 50.72(b)(3)(v)(D). This condition is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(v)(A),10 CFR 50.73(a)(2)(v)(C), and 10 CFR 50.73(a)(2)(v)(D). The NRC Resident Inspector has been notified of this event. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officer's report guidance: The plant entered an 8 hour limiting condition for operation based on the above. The condition was resolved at 2053 CDT when the system was restored to normal operation. | |
| ENS 56163 | 14 October 2022 14:07:00 | Limerick | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection | The following information was provided by the licensee via email: Unit 1 High Pressure Coolant Injection (HPCI) was declared inoperable due to an inadvertent division 2 isolation signal and subsequent valve closure. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of the safety function of a system that is needed to mitigate the consequences of an accident. The NRC Resident will be notified. | |
| ENS 56135 | 30 September 2022 20:08:00 | Saint Lucie | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 1608 (EDT) on September 30, 2022, it was discovered that both trains of the chemical volume and control system were simultaneously inoperable due to an unisolable piping flaw inside containment detected during plant pressurization in preparation for startup following a refueling outage. St. Lucie Unit 2 was not affected and remains at 100 percent power. This event is being reported pursuant to 10CFR50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified.
The following information was provided by the licensee via email: The purpose of this notification is to retract a previous report made on 09/30/2022 at 1713 EDT (EN 56135). Notification of the event to the NRC was initially made as a result of declaring both trains of U1 Chemical and Volume Control System inoperable due to a piping flaw detected during plant pressurization in preparation for startup following a refueling outage. Subsequent to the initial report, FPL (Florida Power and Light) has concluded that the flaw identified in line 2"-CH-109 did not exceed (with sufficient margin) the allowable axial flaw size utilizing the ASME Code Case N-869 methodology, and the Chemical and Volume Control System was operable but degraded for the period of concern. Therefore, this event is not considered a Safety System Functional Failure and is not reportable to the NRC as a Licensee Event Report (LER) per 10 CFR 50.73. The NRC Senior Resident Inspector has been notified. Notified R2DO (Miller). | ||
| ENS 56128 | 26 September 2022 21:41:00 | Saint Lucie | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 1741 EDT on September 26, 2022, it was discovered that both trains of the chemical volume and control system were simultaneously inoperable due to an unisolable piping flaw detected during plant pressurization in preparation for startup following refueling outage. St. Lucie Unit 2 was not affected and remains at 100 percent power. This event is being reported pursuant to 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified.
The following information was provided by the licensee via email: The purpose of this notification is to retract a previous report made on 09/26/2022 at 2239 EDT (EN 56128). Notification of the event to the NRC was initially made as a result of declaring both trains of U1 Chemical and Volume Control System inoperable due to a piping flaw detected during plant pressurization in preparation for startup following a refueling outage. Subsequent to the initial report, FPL (Florida Power and Light) has concluded that the flaw identified in line 2"-CH(1)104 did not exceed (with sufficient margin) the allowable axial flaw size utilizing the ASME Code Case N-869 methodology, and the Chemical and Volume Control System was Operable but degraded for the period of concern. Therefore, this event is not considered a Safety System Functional Failure and is not reportable to the NRC as a Licensee Event Report (LER) per 10 CFR 50.73. The NRC Senior Resident Inspector has been notified. Notified R2DO (Miller). | ||
| ENS 56116 | 19 September 2022 06:32:00 | River Bend | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Service water Reactor Core Isolation Cooling High Pressure Core Spray | The following information was provided by the licensee via email: At 0132 CDT on September 19, 2022, River Bend Station (RBS) was operating at 100% power when the high pressure core spray (HPCS) system was declared inoperable in accordance with technical specification 3.8.9, condition E (declare HPCS and standby service water system pump 2C inoperable immediately) due to a E22-S003, HPCS transformer feeder malfunction. The HPCS is a single train system at RBS, therefore this event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfilment of a safety function. The reactor core isolation cooling system has been verified to be operable. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: RBS has entered a 14-day limiting condition for operation due to the loss of HPCS and they have upgraded their on-line plant risk model to "yellow". | |
| ENS 56058 | 19 August 2022 17:15:00 | Grand Gulf | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Automatic Depressurization System | The following information was provided by the licensee via email: At 1215 CDT on 8/19/2022, with Grand Gulf Nuclear Station in Mode 1 and at 100 percent power, four Automatic Depressurization System (ADS) valves were rendered inoperable due to a loss of system pressure. The station entered Technical Specification 3.5.1 Condition G. This event is being reported under 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. There were no other systems affected as a result of this condition. The NRC Senior Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Plans are to remain in Mode 1 until corrected or until driven by the Technical Specifications to shut down (12-hour LCO from 1215 CDT on 8/19/2022).
Grand Gulf Nuclear Station (GGNS) is performing this notification to retract event EN 56058 that was reported on August 19, 2022. Previously, GGNS notified the NRC that four Automatic Depressurization System (ADS) valves were inoperable due to a loss of system pressure. Based upon further investigation, the condition reported in EN 56058 was found to affect only a single ADS valve. As a result, it was determined that an event or condition that could have prevented the fulfillment of a safety function did not exist at GGNS. Sufficient redundancy existed to perform the safety function. The NRC Resident Inspector has been notified of the retraction. R4DO (Kellar) was notified. | |
| ENS 56054 | 18 August 2022 01:08:00 | Fermi | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling HVAC Automatic Depressurization System Emergency Equipment Cooling Water | The following information was provided by the licensee via email: At 2108 EDT on August 17, 2022 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 Division 2 EECW system cools various safety related components, including the High Pressure Coolant Injection (HPCI) room cooler and Division 2 Control Center HVAC (CCHVAC) chiller. An unplanned HPCI inoperability occurred based on a loss of the HPCI Room Cooler. At the time of the event, Division I CCHVAC was inoperable for maintenance (but was running for a maintenance run) and the event caused an inoperability of Division 2 CCHVAC. This resulted in an inoperability of both divisions of CCHVAC. Failure of the Division 2 MDCT Fan brake inverter occurred due to a trip of the DC input breaker. The breaker was reset at 2128 EDT restoring Division 2 UHS Operability. This report is being made pursuant to 10CFR50.72(b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfilment of the safety function of structures or systems that are needed to mitigate the consequences of an accident based on a loss of a single train safety system and loss of both divisions of a safety system. The Senior NRC Resident Inspector has been notified
The following information was provided by the licensee via email: On 8/17/22 at 2108 EDT the Division 2 (Div. 2) mechanical draft cooling tower (MDCT) brake inverter input breaker tripped for an unknown cause. The result of the loss of power was the inoperability of the MDCT fan brakes which impacts the ultimate heat sink (UHS) (TS 3.7.2). The UHS cascades to the EECW (emergency equipment cooling water) (TS 3.7.2) which is a support system for Div. 2 CCHVAC (Control Cell) Chiller A/C system (TS 3.7.4). This resulted in the inoperability of the Div. 2 CCHVAC Chiller. The cause for the breaker to trip is an intermittent electrical transient. Immediate corrective action was to reset the breaker, and the long-term action is to implement a modification to mitigate susceptibility to voltage variations. Div. 1 has implemented this long-term mod and no unexpected trips have occurred to date. Div. 1 CCHVAC Chiller was previously inoperable from equipment issues which was repaired, and the unit was in service for a 24-hour confidence run. Although licensed personnel had not completed the administrative actions for documenting operability during the 24-hour confidence run to monitor parameters, the (post maintenance test) PMT related to the maintenance was already completed, which included a 4-hour run in accordance with surveillance 24.413.01, Div. 1 and Div. 2 Chilled Water Pump and Valve, to verify normal operation and motor current. These PMT's were completed prior to the identified inoperability of the Div. 2 UHS due to the tripped breaker on the brake power supply. At the time of the MDCT brake inverter trip, the Operations' Senior License and the Night Shift Manager were aligned that, although still operating as part of the 24-hour confidence run, the unit was in service and capable of performing its safety function, but the administrative tasks were not completed, the Limited Condition of Operation (LCO) sheet had not been cleared, and no log entries were made. Since the Div. 1 Chiller was, in fact, operable at the time of the trip of the breaker on the inverter, this would allow the use of Technical Specification (TS) 3.0.9 'Barriers'. Per Operations Department Expectation (ODE)-12 `LCOs' (standard guidance and expectations for preparing and implementing an LCO), Operations determined that the MDCT brakes are barriers to a tornado event and TS 3.0.9 could be utilized. By invoking TS 3.0.9, as long as all other supported systems in the other division are operable, Div. 2 supported systems relying upon the UHS can remain operable and the Automatic Depressurization System (ADS) and Reactor Core Isolation Cooling (RCIC) system can be used as backup to the High Pressure Coolant Injection (HPCI) system. Based on this information, there was no loss of safety function with CCHVAC A/C system or HPCI. Therefore, the NRC non-emergency 10CFR50.72(b)(3)(v)(D) report was not required and the NRC report 56054 can be retracted. The NRC Resident Inspector has been notified. Notified R3DO (Orlikowski) | |
| ENS 55997 | 16 July 2022 00:20:00 | Brunswick | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling Automatic Depressurization System | The following information was provided by the licensee via email: At 2020 Eastern Daylight Time (EDT) on July 15, 2022, the HPCI System was declared inoperable. Therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The Reactor Core Isolation Cooling (RCIC) System and Automatic Depressurization System (ADS) were operable during this time. HPCI availability was restored at 2023. Additional investigation is in-progress. There was no impact on the health and safety of the public or plant personnel. Unit 2 is not affected by this event. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: HPCI is considered inoperable but available at this time, resulting in a 14-day Shutdown LCO (Limiting Condition for Operation), due to the HPCI inoperability. | |
| ENS 55992 | 12 July 2022 14:17:00 | Browns Ferry | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Reactor Core Isolation Cooling Automatic Depressurization System | The following information was provided by the licensee via fax or email: At 0917 CDT on 7/12/2022, during the performance of U1 (Unit 1) High Pressure Coolant Injection (HPCI) rated flow test, the 1-FCV-73-19 (HPCI governor valve) failed to operate as expected. This condition results in U1 HPCI being inoperable; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The Automatic Depressurization System (ADS) and Reactor Core Isolation Cooling (RCIC) system remain operable. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. U1 entered TS LCO 3.5.1 Condition C, 14-day Shutdown LCO (Limiting Condition for Operation), due to the HPCI inoperability. | |
| ENS 55976 | 4 July 2022 06:30:00 | Quad Cities | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary containment Standby Gas Treatment System | The following information was received from the licensee via email: At 0130 CDT on July 4 2022, it was discovered both trains of Standby Gas Treatment System were simultaneously inoperable due to failure to reach required flow rates. Both trains were capable of starting but failed to reach the required flow of 4000 SCFM. Secondary Containment differential pressure was not able to be maintained at greater than or equal to 0.25 inches of vacuum water gauge, causing Secondary Containment to also be inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 55962 | 24 June 2022 16:57:00 | Perry | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Core Spray | The following information was provided by the licensee via telephone: At 1257 EDT on June 24, 2022, it was discovered the Low Pressure Core Spray System (LPCS) was INOPERABLE. At Perry, the Low Pressure Core Spray System is considered a single train system in Modes 1, 2, and 3; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Inoperability of the Low Pressure Core Spray system was caused by a loss of power to the LPCS Minimum Flow Valve during surveillance activities. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 55955 | 22 June 2022 02:40:00 | McGuire | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 2240 on 06/21/2022, it was discovered that both required trains of Control Room Ventilation and Control Area Chilled Water System were simultaneously inoperable; therefore, this condition is being reported as an eight-hour, nonemergency notification per 10 CFR 50.72(b)(3)(v)(d). 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 'B' train was restored at 2315. | ||
| ENS 55908 | 23 May 2022 17:56:00 | LaSalle | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via fax: At 1256 CST on 05/23/2022, it was discovered both trains of Control Room Area Ventilation Air Conditioning Systems were simultaneously INOPERABLE. Due to this INOPERABILITY, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | ||
| ENS 55907 | 23 May 2022 09:55:00 | Cooper | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary containment | The following information was provided by the licensee via email: On May 23, 2022, at 0455 CST, Cooper Nuclear Station experienced a spike in Secondary Containment differential pressure which exceeded the Technical Specifications Surveillance Requirements 3.6.4.1.1 limit of -0.25 inches of water gauge. Secondary Containment differential pressure restored to Technical Specification limits within two minutes and further investigation is ongoing. This unplanned Secondary Containment inoperability constitutes a condition reportable under 10CFR50.72(b)(3)(v)(C) and (D). The NRC Senior Resident Inspector has been informed. | |
| ENS 55905 | 20 May 2022 14:05:00 | LaSalle | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | The following information was provided by the licensee via email: At 0905 CST on 05/20/2022, it was discovered both trains of Control Room Area Filtration and Area Ventilation Air Conditioning Systems were simultaneously INOPERABLE. Due to this INOPERABILITY, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | ||
| ENS 55896 | 13 May 2022 16:11:00 | Monticello | 10 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 55894 | 11 May 2022 22:14:00 | Fermi | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection | The following information was provided by the licensee via email: During performance of High Pressure Coolant Injection (HPCI) Pump and Valve Operability surveillance in accordance with procedure 24.202.01, the turbine tripped without operator action. The plant was operating in Mode 1 at 10 percent power with the HPCI turbine running in a test mode at 5100 gpm with all surveillance criteria met. The surveillance was near completion at the point where the HPCI turbine is manually tripped. Before the manual trip was performed, the HPCI turbine tripped without operator action. Prior to performance of the surveillance, HPCI was provisionally operable with only satisfactory completion of Post Maintenance Testing (PMT) surveillance remaining to declare HPCI operable. HPCI surveillance testing was performed at low reactor pressure (165 psig) in Mode 2 satisfactorily. Investigation into the cause of this trip is in progress. HPCI has been declared inoperable from the time of release of the surveillance. Reactor Coolant Isolation Cooling (RCIC) was verified to be operable prior to and after the surveillance in accordance with Technical Specifications 3.5.1 condition E.1. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) based on an unplanned HPCI inoperability. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |