Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 54885 | 5 September 2020 02:27:00 | On September 4, 2020, DC Cook Unit 2 experienced a lowering Reactor Coolant System (RCS) pressure caused by a failed open Reactor Coolant Pressurizer Spray valve. At approximately 2242 (EDT), a manual Reactor Trip was performed due to the lowering RCS pressure. Following the manual reactor trip, an automatic Safety Injection was actuated due to the lowering RCS pressure. RCS pressure has recovered to normal and is stable. This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation, and 10 CFR 50.72(b)(2)(iv)(A), ECCS Discharge to RCS, as a four (4) hour report. Notification is also being made as an 8 hour report under 10 CFR 50.72(b)(3)(iv)(A), Reactor Protection System (RPS), Containment Isolation, Emergency Core Cooling (ECCS), Auxiliary Feedwater System (AFW), and Emergency AC Electrical Power actuations. The DC Cook Resident NRC Inspector has been notified. Unit 2 is being supplied by offsite power. All control rods fully inserted. Aux Feedwater Pumps started as required and are operating properly. All ECCS components operated as required including Containment Isolation. Decay heat is being removed via the Condenser Steam Dumps and ECCS has been secured. Three of four Reactor Coolant Pumps were secured and RCS pressure has recovered to normal pressure and is stable. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip and Safety Injection. DC Cook Unit 2 remains stable in Mode 3. No radioactive release is in progress as a result of this event. Unit 1 was not affected and remains in Mode 1, 100 % power. |
| ENS 54176 | 21 July 2019 12:08:00 | On July 19, 2019, DC Cook Unit 2 started experiencing degraded performance on the Unit 2 Non-Essential Service Water System (NESW) which affected one (1) NESW pump. On July 21, 2019, a second NESW pump on Unit 2 experienced degradation. On July 21, 2019, DC Cook Unit 2 elected to do a rapid downpower over approximately 40 minutes and perform a Manual Reactor Trip from 17 percent (rated thermal power) to repair the condition before any threshold was exceeded. The manual reactor trip was completed at 0826 EDT on July 21, 2019. This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), Reactor Protection System (RPS), as an eight (8) hour report. The DC Cook NRC Resident Inspector has been notified. Unit 2 is being supplied by offsite power. All control rods fully inserted. Aux Feedwater pumps were started as required and are operating properly. Decay heat is being removed via the Steam Generator Power Operated Relief Valves following breaking Main Condenser Vacuum for expedited cooldown of the Main Turbine. Preliminary evaluation indicates all plant systems functioned normally following the reactor trip. DC Cook Unit 2 remains stable in Mode 3. No radioactive release is in progress as a result of this event. Unit 1 was not affected. |
| ENS 53230 | 27 February 2018 01:15:00 | At 2247 Eastern (Standard) Time the Unit 1 Control Room was notified of a personnel injury in the Unit 1 lower containment. Unit 1 is currently in Mode 1 at 100 (percent) (Reactor) Power and the individual was working in lower containment. The individual's injury appears to be Heat Exhaustion. Site emergency medical technicians responded to the scene and the individual was transported to a local medical facility via ambulance. At the time of transport, the individual was considered to be potentially contaminated because complete surveys could not be performed while the individual was immobilized for transfer. The individual and clothing were surveyed at the hospital by a resident Radiation Protection Technician and no contamination was found. This report is being made pursuant to 10 CFR 50.72(b)(3)(xii), 'Any event requiring the transport of a radioactively contaminated person to an offsite medical facility for treatment.' The NRC Resident Inspector has been notified. |
| ENS 50587 | 1 November 2014 05:03:00 | On November 1, 2014, at 0249 (EDT), DC Cook Unit 1 reactor was manually tripped and at 0248 (EDT) DC Cook Unit 2 was manually tripped due lowering condenser vacuum caused by degraded forebay conditions (observed thick grass and sand). U-1 and U-2 entered Abnormal Operating Procedure for Degraded Forebay on November 1, 2014 at 0153 (EDT). Conditions degraded in U-1 and U-2 until all but 2 screens in each unit were tripped on overload and main condenser vacuum was lowering. U-1 and U-2 met criteria in the Degraded Forebay procedure to remove the units from service and remove all circulating water pumps from service. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation, as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight (8) hour report. The electrical grid is stable. Unit 1 and Unit 2 are being supplied by offsite power. All control rods fully inserted in both units. Decay heat is being removed by steam generator PORVs. Preliminary evaluation indicates all plant systems functioned normally following the reactor trip with the exception of U-1 turbine driven auxiliary feed pump. DC Cook Unit 1 and Unit 2 remain stable in Mode 3 while conducting the post trip review. No radioactive release is in progress as a result of this event. Additional information received determined the Unit 1 turbine driven auxiliary feedwater pump tripped for unknown reasons. Feedwater flow to all steam generators was maintained by the U-1 east and west motor driven auxiliary feedwater pumps. U-2 reactor power was lowered from 100 percent to 50 percent over the hour prior to the trip in accordance with the Degraded Forebay Procedure. The DC Cook NRC Resident Inspector has been notified.
At 0921 EDT, DC Cook issued a press release regarding the event described earlier. The licensee notified the NRC Resident Inspector. Notified R3DO (Lipa) |