Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56186 | 28 October 2022 00:50:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Auxiliary Feedwater System Inoperable | 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. | Steam Generator Auxiliary Feedwater | |
| ENS 55040 | 17 December 2020 20:39:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Accumulator Discharge Valves Isolated with Plant Greater than 1000 Psig | On December 17, 2020 at 1539 EST, with Harris Nuclear Plant Unit 1 preparing for entry into Mode 4, the Reactor Coolant System was pressurized greater than 1000 psig for approximately 15 minutes with all three Cold Leg Injection Accumulator Discharge Valves closed. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Both Low Head and High Head Safety Injection Systems were operable at this time. This condition does not affect the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | Reactor Coolant System | |
| ENS 54008 | 17 April 2019 12:12:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Turbine Trip Solenoids Failure to Actuate | At 0812 EDT on 4/17/2019, it was discovered that both sets of turbine trip solenoids were previously unable to actuate within the allowable time frames; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). At the time of discovery, one set of turbine trip solenoids had been restored. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | ||
| ENS 53486 | 3 July 2018 04:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Turbine Trip Solenoid Failed to Actuate During Testing | At 1753 on 7/3/2018 it was discovered that both sets of turbine trip solenoids were previously unable to actuate within allowable time frames; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). At the time of discovery, one set of turbine trip solenoids had been restored. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | ||
| ENS 52291 | 8 October 2016 17:28:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unusual Event Declared Due to Loss of Offsite Power | Loss of all offsite power capability, Table S-5, to 6.9kV emergency buses 1A-SA and 1B-SB for greater than or equal to 15 minutes. At 1328 EDT, while shutdown in Mode 4 (Hot Shutdown), Harris declared an Unusual Event due to a loss of offsite power. Following the loss of offsite power (LOOP), the Emergency Diesel Generators started and loaded onto their respective emergency buses. The reactor remains stable and shutdown in Mode 4. The licensee is currently investigating the cause of the LOOP and the emergency buses will continue to be powered by the EDGs until the licensee has determined the cause for the LOOP. Offsite power is currently available into the switchyard. The licensee notified the state government, the local government, and the NRC Resident Inspector. Notified DHS SWO, FEMA OPS Center, FEMA National Watch (email only), DHS NICC, Nuclear SSA (email only).
The cause (of the LOOP) is not known. Duke Energy Control Center has evaluated the grid and is comfortable with Harris connecting emergency buses back to the grid. Harris Plant is evaluating restoration. Faults were validated on the 115kV Cape Fear North and South supply lines into the Harris switchyard. This notification also addresses various valid actuations of safety systems, including the Emergency Diesel Generators, as well as, potential loss of Emergency Assessment Capabilities due to the LOOP impacting Emergency Planning equipment. The licensee notified the NRC Resident Inspector. Notified R2DO (Bonser), IRD (Grant), and NRR EO (King).
The cause of the LOOP has been determined to be a momentary electricity loss on the 115kV Cape Fear North and South supply lines into the Harris switchyard. This event notification also addresses the loss of safety function of the offsite power system which occurred as a result of grid perturbations. The licensee notified the NRC Resident Inspector. Notified R2DO (Bonser), IRD (Grant), and NRR EO (King).
Based on the grid being stable and the 115kV Cape Fear North and South lines being available, the licensee terminated the Unusual Event at 2049 EDT on 10/8/16. The licensee notified the NRC Resident Inspector. Notified R2DO (Bonser), IRD (Grant), and NRR EO (King). Notified DHS SWO, FEMA OPS Center, FEMA National Watch (email only), DHS NICC, Nuclear SSA (email only).
10 CFR 50.72(b)(2)(XI) - OFFSITE NOTIFICATION At approximately 1305 EDT on October 9, 2016, Duke Energy personnel notified the North Carolina Department of Environment and Natural Resources of a spill of untreated sanitary wastewater. During a significant rainfall event associated with Hurricane Matthew, wastewater was released from the overflow of a lift station that did not function as a result of a power outage. The untreated sanitary wastewater entered the plant's storm drain system. The release has been stopped and the lift station power is restored. An investigation is in progress to further determine the cause and additional corrective actions. There is no impact to public health and safety or the environment due to this incident. This event is reportable per 10 CFR 50.72(b)(2)(xi), an event related to protection of the environment for which a notification to other government agencies has been made. The NRC Resident Inspector has been notified. Notified R2DO (Bonser). | Emergency Diesel Generator | |
| ENS 52192 | 22 August 2016 02:51:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Loss of Control Room Hvac | At 2251 EDT on 8/21/2016, the 'A' Train of Control Room ventilation was inoperable for scheduled testing and the 'B' Train of Control Room ventilation was declared inoperable due to a thermal overload of a cooling fan. This resulted in not meeting the limiting condition for operation in accordance with Technical Specification 3.7.6. No action statement exists for having two trains of Control Room Ventilation inoperable and Technical Specification 3.0.3 was applied. At 2255 on 8/21/2016 the 'A' Train of Control Room Ventilation was declared operable and Technical Specification 3.0.3 was exited. The licensee notified the NRC Resident Inspector.
Event notification 52192 is being retracted. Upon further evaluation, Harris determined that the 'A' train of Control Room Emergency Filtration was Operable at the time 'B' train became Inoperable. Therefore, there was no loss of safety function. The NRC Resident Inspector has been informed of this retraction. Notified R2DO (Rose). | ||
| ENS 52072 | 7 July 2016 16:10:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Accident Mitigation - Main Steam Safety Valves Not Adequately Protected from Tornado Missiles | During an evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornados, Harris Nuclear Plant personnel identified conditions in the plant design such that specific TS equipment is considered not adequately protected from tornado missiles. A tornado could generate multiple missiles capable of striking exhaust piping on multiple main steam safety valves (MSSVs), resulting in crimping of the piping that could impact flow capacity and render the MSSVs inoperable. If the tornado caused a loss of offsite power, the MSSVs are credited to remove decay heat to achieve cold shutdown. Compensatory measures have been implemented to ensure safety in the event of a tornado. Enforcement discretion per Enforcement Guidance Memorandum EGM 15-002 and Interim Staff Guidance DSS-ISG-2016-01 has been implemented and required actions taken. Corrective actions will be documented in a follow-on licensee event report. The licensee has notified the NRC Resident Inspector. | Main Steam Safety Valve | |
| ENS 51601 | 13 December 2015 08:07:00 | 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 | Essential Services Chilled Water System Inoperable | This is a non-emergency eight hour notification for a condition that could have prevented fulfillment of a safety function in a system needed to remove decay heat and to mitigate the consequences of an accident. At approximately 0307 EST on December 13, 2015, the 'A' and 'B' trains of the essential services chilled water (ESCW) system were inoperable for a time period of 23 minutes. The 'B' train of the ESCW system was being tested at the time that the 'A' train of the ESCW system became inoperable. The 'B' train of the ESCW system was returned to operable status at approximately 0330 EST and remains operable. The ESCW system provides cooling support functions to remove decay heat and mitigate the consequences of an accident. There were no safety system actuations during this time period and the plant is stable. This condition does not affect the health and safety of the public or station employees. The NRC Resident Inspector has been notified. The 'A' ESCW pump tripped on low lube oil pressure.
Upon further review of the condition, it was determined that the 'A' train of the ESCW system was capable of performing its safety function throughout the time period previously reported, and the 'A' train of the ESCW system was operable. Therefore, there was no loss of safety function. Event notification 51601 is retracted. The NRC Resident Inspector has been informed of this notification retraction. Notified the R2DO (Guthrie). | ||
| ENS 51178 | 16 June 2015 15:45:00 | 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 | Unanalyzed Condition Due to Open High Energy Line Break Doors | On June 16, 2015 at 1145 EDT while in Mode 1 at 100% power steady-state conditions, two fire doors between the Reactor Auxiliary building (RAB) and steam tunnel were opened under administrative controls to support maintenance. These doors are credited in high energy line break equipment qualification and internal flooding analyses and opening of the doors is not addressed in the analyses. A high energy line break in the steam tunnel with the doors open could result in equipment in the RAB experiencing high temperature, pressure, or humidity beyond conditions analyzed for equipment qualification which has the potential to render redundant safety-related equipment inoperable. The event was determined to be reportable on June 24, 2015 at approximately 1550 (EDT). During that reportability evaluation, it was determined that the doors may have been in a similar condition multiple times in the May-June time frame. This condition is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition and in accordance with 10 CFR 50.72(b)(3)(v)(D) as a condition that could have prevented the fulfillment of the safety function of structures or system that are needed to mitigate the consequences of an accident. There was no adverse impact to public health and safety or to plant employees. The NRC Resident Inspector has been notified. | ||
| ENS 51011 | 4 April 2015 15:20:00 | 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 | Power Lost to Control Room Normal Outside Air Intake Dampers During Testing | On April 4, 2015, during testing of the Control Room ventilation system while in Mode 5 at 0% power during shutdown for a refueling outage, the 1CZ-1 and 1CZ-2 Control Room Normal Outside Air Intake dampers lost power due to circuit breaker trips, preventing closure. Harris personnel immediately closed the dampers as required by Harris Nuclear Plant Technical Specifications. During subsequent evaluation, this event was determined to be reportable on April 24, 2015, at approximately 1200 EDT. This event is being reported under the non-emergency notification requirement of 10 CFR 50.72 (b)(3)(v)(A), 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to shut down the reactor and maintain it in a safe shutdown condition,' and 50.72(b)(3)(v)(D), 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' There was no adverse impact to public health and safety or to plant employees. The NRC Resident Inspector has been notified. | ||
| ENS 47857 | 21 April 2012 09:15:00 | 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 | Main Steam Isolation Valves Fail to Shut | At approximately 0515 EDT on April 21, 2012, the Harris Nuclear Plant (HNP) was in the process of a normal plant shutdown for a refueling outage. HNP was at 0% power in Mode 4. During OST-1046, MSIV Operability Test, 'B' and 'C' Main Steam Isolation Valves (MSIV), failed to close from the main control board. At 0648 EDT an April 21, 2012 'B' MSIV shut immediately after the instrument air supply was isolated. At 0938 EDT an April 21, 2012 'C' MSIV shut after the instrument air supply was isolated. The cause of the equipment failure is not yet known but is currently being investigated. This report is being made in accordance with 10 CFR 50.72 (b)(3)(v)(C), inability to isolate and mitigate a radioactive release, and 10 CFR 50.72 (b)(3)(v)(D), a condition which could have prevented the fulfillment of a safety function to mitigate the consequences of an accident. The plant continues to remain shutdown at 0% power. Other equipment functioned as expected including the turbine isolation valves. The licensee notified the NRC Resident Inspector.
Investigation into the condition revealed the instrument air supply to the MSIVs was isolated at 0530 EDT and 'B' MSIV indicated (drifted) shut at 0607 EDT. The plant is currently in Mode 6, Refueling, and the investigation is ongoing. The licensee notified the NRC Resident Inspector. Notified R2DO (Musser). | Main Steam Isolation Valve |