| | Site | Start date | Title | Description |
|---|
| ENS 57187 | Vogtle | 22 June 2024 11:28:00 | Manual Actuation of Reactor Protection System (Rps) | The following information was provided by the licensee via email:
At 0728 EDT on 06/22/2024, with Unit 2 in Mode 3 at zero percent power and the reactor trip breakers closed, a manual actuation of the RPS was initiated during the withdrawal of the shutdown rods in preparation for Mode 2. This was procedurally directed due to a shutdown rod being misaligned from the other rods in the bank due to a malfunction.
Units 1, 3 and 4 were not affected.
Due to the manual actuation of the RPS, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A).
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | | ENS 57175 | Waterford | 16 June 2024 17:33:00 | Automatic Reactor Trip | The following information was provided by the licensee via email:
On June 16, 2024, at 1233 CDT, Waterford Steam Electric Station Unit 3 was operating at 93 percent power when an automatic reactor trip occurred. Immediately following the reactor trip, emergency feedwater (EFW) actuated automatically. The unit is currently in Mode 3. All control rods fully inserted. Decay heat removal is via the main condenser. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip, except steam generator (SG) feedwater pump 'A' tripped and SG '1' main feed regulatory controller went to manual. Steam generator water levels are being controlled with the SG feedwater pump 'B'. The cause of the trip is currently being investigated.
This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system when the reactor is critical and as an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as a valid actuation of the EFW system.
The NRC Resident Inspector has been notified. | | ENS 57164 | Vogtle | 5 June 2024 20:48:00 | Manual Reactor Trip | The following information was provided by the licensee via email:
At 1648 EDT on 06/05/2024, with Unit 4 in Mode 1 at approximately 35 percent power, the reactor was manually tripped due to unexpected response of the turbine run back circuitry following a trip of main feedwater pump `C. The trip was not complex, with all safety systems responding normally post-trip.
Operations responded and stabilized the plant. Decay heat is being removed by discharging steam through the steam dumps to the main condenser and main feedwater is supplying the steam generators. Units 1, 2 and 3 are not affected.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | | ENS 57163 | Columbia | 5 June 2024 04:41:00 | Primary Containment Isolation Due to Loss of Rps Power Supply | The following information was provided by the licensee via fax or email:
On June 4, 2024, at 2141 PDT, with the unit in Mode 1 at 100 percent power, the reactor protection system (RPS) B power supply unexpectedly de-energized which caused containment isolations to occur in reactor water clean up, equipment drains radioactive, floor drains radioactive, reactor recirculation, and traversing in-core probe systems. All actuations occurred as designed upon the partial loss of RPS power.
This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) as a major loss of emergency assessment capability due to the inability to assess primary containment identified and unidentified leakage rates. Emergency assessment capability was restored at 2204.
The NRC Senior Resident has been notified. | | ENS 57158 | Surry | 2 June 2024 21:08:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
Surry Unit 1 reactor automatically tripped at 1708 EDT on 6/2/24 due to a turbine trip (with the reactor operating at greater than 10 percent reactor power).
The turbine control system is currently under investigation. Reactor coolant temperature is being maintained via main steam dumps with main feedwater supplying the steam generators.
All systems operated as required. The trip was uncomplicated and all control rods fully inserted into the core. There was no emergency core cooling system (ECCS) or auxiliary feedwater system actuation. Offsite power remains available. There is no impact to Surry Unit 2.
This notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) for 4-hour notification of reactor protection system activation. The NRC Resident Inspector has been notified.
There were no radiation releases, personnel injuries, or contamination events due to this event. | | ENS 57155 | Harris | 30 May 2024 23:49:00 | Automatic Reactor Trip | The following information was provided by the licensee via email and phone:
On May 30, 2024, at 1949 EDT, Unit 1 automatically tripped from 100 percent power due to an electrical fault on the B unit auxiliary transformer. The unit has been stabilized in mode 3 at normal operating temperature and pressure. The reactor trip was uncomplicated and all control rods fully inserted into the core. This reactor protection system actuation is reportable per 10 CFR 50.72(b)(2)(iv)(B). Decay heat is being removed by the condenser steam dump system and Unit 1 is in a normal shutdown electrical lineup. There was no impact on the health and safety of the public or personnel.
The NRC Resident Inspector has been notified. | | ENS 57148 | North Anna | 29 May 2024 10:24:00 | Automatic Reactor Trip | The following information was provided by the licensee via email and phone:
On May 29, 2024, at 0624 EDT, Unit 1 automatically tripped from 100 percent power due to a negative rate trip. The unit has been stabilized in mode 3 at normal operating temperature and pressure. The reactor trip was uncomplicated and all control rods fully inserted into the core. This reactor protection system actuation is reportable per 10 CFR 50.72(b)(2)(iv)(B). The auxiliary feedwater pumps actuated as designed because of the reactor trip and is reportable per 10 CFR 50.72(b)(3)(iv)(A) for a valid engineered safety feature (ESF) actuation. Decay heat is being removed by the condenser steam dump system and Unit 1 is in a normal shutdown electrical lineup. Unit 2 was not affected by this event.
The NRC Resident has been notified. | | ENS 57141 | Quad Cities | 23 May 2024 16:46:00 | Automatic Scram Due to Turbine Trip Signal | The following information was provided by the licensee via email:
At 2223 CDT on May 23, 2024, with Quad Cities Unit 2 at 38 percent power, the reactor automatically tripped due to a turbine trip signal resulting in main stop valve closure, creating a valid reactor protection system signal. Reactor vessel level reached the low-level set-point following the scram, resulting in valid Group II and Group III containment actuation signals. The trip was not complex with all systems responding as expected post-trip. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group II and Group III isolation.
Operations responded using their emergency operating procedures and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves.
Unit 1 remains at 100 percent power.
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:
Unit 2 was at a reduced power for maintenance. | | ENS 57132 | Beaver Valley | 19 May 2024 04:30:00 | Manual Reactor Trip | The following information was provided by the licensee via email:
At 0030 (EDT) on 5/19/24, with Beaver Valley Unit 1 in mode 1 at 14 percent power, the reactor was manually tripped due to inability to control the A steam generator water level. The trip was not complex, with all systems responding normally post-trip. The turbine driven auxiliary feedwater pump automatically started on a valid actuation signal. All control rods inserted into the core. Operations responded and stabilized the plant. Decay heat is being removed by the feedwater system and the main condenser. Beaver Valley Unit 2 is unaffected.
Due to the reactor protection system system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Due to the emergency safety feature system actuation (automatic start of the turbine driven auxiliary feedwater pump) while critical, this event is being reported as an eight-hour, non-emergency notification per 10CFR 50.72(b)(3)(iv)(A).
There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector has been verbally notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Unit 1 is stable on off-site power, normal configuration. All emergency systems are available. | | ENS 57128 | Cook | 15 May 2024 08:27:00 | Unit 2 Manual Reactor Trip | The following information was provided by the licensee via email:
On May 15, 2024 at 0427 EDT, DC Cooks Unit 2 reactor was manually tripped due to difficulty maintaining steam generator water levels.
DC Cook Unit 2 had removed the main turbine from service at approximately 0354 EDT during a planned down-power to repair a steam leak on the high pressure turbine right outer steam/stop control valve upstream drip pot. Stable steam generator water levels were unable to be maintained. As a result, DC Cook Unit 2 was manually tripped with reactor power stabilizing at approximately 20 percent.
This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System actuation as a four hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight hour report.
The reactor trip was not complicated and all plant systems functioned normally. The DC Cook NRC Resident Inspector was notified. |
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