| | Site | Start date | Title | Description |
|---|
| ENS 57418 | Grand Gulf | 10 November 2024 09:37:00 | Manual Reactor Scram | The following information was provided by the licensee via phone and email:
On November 10, 2024, at 0337 CST, Grand Gulf Nuclear Station (GGNS) was operating in mode 1 at 100 percent power when a manual scram was initiated due to degrading main condenser vacuum. The cause of the degrading main condenser vacuum is not known at this time and is being investigated. All control rods fully inserted and there were no complications. Reactor pressure was initially maintained with main turbine bypass valves. Reactor water level was initially maintained with main feedwater and condensate.
At 0457, operators transitioned pressure control to safety relief valves and began using reactor core isolation cooling (RCIC) to maintain reactor water level. This was performed using plant procedures due to degrading vacuum. GGNS is currently in mode 3. Reactor level is being maintained with RCIC and pressure is being maintained using the safety relief valves.
The manual reactor protection system (RPS) actuation is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) and the RCIC actuation is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A).
The NRC Senior Resident Inspector was notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
At the time of the notification, main steam isolation valves had shut on low vacuum.
- * * UPDATE ON 11/10/24 AT 1236 CST FROM MELISSA LIMBECK TO KERBY SCALES * * *
The following update was provided by the licensee via phone and email:
This update is being made to report the following occurrences which took place after the scram reported in event number 57418.
On November 10, 2024, at 0545 CST, a group 1 containment isolation signal resulted in the closure of all MSIVs. The signal was due to continued degradation of condenser vacuum post-trip. At 0620, an automatic RPS actuation occurred when reactor water level lowered to level 3. This RPS actuation occurred with all control rods fully inserted. Reactor water level lowered following closure of an open safety relief valve and was recovered to within the established band.
The events are being reported as specified system actuations in accordance with 10 CFR 50.72(b)(3)(iv)(A).
The NRC Senior Resident Inspector has been informed of the update.
Notified R4DO (Dixon) |
| IR 05000259/2024003 | Browns Ferry | 4 November 2024 | Integrated Inspection Report 05000259/2024003 and 05000260/2024003 and 05000296/2024003 | |
| IR 05000277/2024003 | Peach Bottom | 4 November 2024 | Integrated Inspection Report 05000277/2024003 and 05000278/2024003 | |
| IR 05000321/2024003 | Hatch | 30 October 2024 | Edwin I Hatch, Units 1 and 2 - Integrated Inspection Report 05000321/2024003 and 05000366/2024003 | |
| ML24283A166 | Clinton | 23 October 2024 | Enclosure 2 Clinton Audit Summary RCI and RAIs | |
| ENS 57372 | Calvert Cliffs | 10 October 2024 09:57:00 | Automatic Reactor Trip Due to Turbine Generator Loss of Field | The following information was provided by the licensee via phone and email:
At 0557 EDT on 10/10/2024, with Unit 2 in mode 1 at 100 percent power, the reactor automatically tripped due to turbine generator loss of field. The trip was not complex with all systems responding normally 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).
Operations responded using EOP-0, post trip immediate actions, and stabilized the plant in mode 3. Decay heat is removed by discharging steam to the main condenser using the turbine bypass valves.
Unit 1 is not affected.
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 exciter is suspected to being the cause and is under investigation. All control rods fully inserted. |
| ML24207A019 | FitzPatrick | 9 October 2024 | SE Addendum Related to the License Amendment No. 338 for Implementation of the Alternative Source Term (DPO-2021-001) | |
| ML24270A004 | FitzPatrick | 2 October 2024 | Fitpatrick Pre-submittal Meeting Slides, October 2, 2024 | |
| ENS 57343 | Hatch | 27 September 2024 07:46:00 | Manual Reactor Trip on Lowering Condenser Vacuum | The following information was provided by the licensee via phone:
At 0346 EDT on 9/27/24, with Unit 1 in mode 1 at 54 percent power, the reactor was manually tripped due to degrading condenser vacuum secondary to environmental conditions. The trip was not complex with all systems responding normally post trip. Closure of containment isolation valves (CIVs) in multiple systems occurred. Operations responded and stabilized the plant.
The reactor protection system actuation while critical event is being reported as a 4-hour non-emergency notification per 10 CFR 52.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 52.72(b)(3)(iv)(a) as an event that results in a valid actuation of the CIVs.
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:
Decay heat removal is via steam bypass to the main condenser. Unit 2 was not affected. |
| BW240053, Revised 2022 Annual Radioactive Effluent Release Report | Braidwood | 6 September 2024 | Revised 2022 Annual Radioactive Effluent Release Report | |