ENS Event | |
|---|---|
02:42 Sep 5, 2020 | |
| Title | Manual Reactor Trip and Automatic Safety Injection |
| Event Description | 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 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 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. |
| Where | |
|---|---|
Cook  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-0.25 h-0.0104 days <br />-0.00149 weeks <br />-3.4245e-4 months <br />) | |
| Opened: | Perry Graham 02:27 Sep 5, 2020 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | Sep 5, 2020 |
| 54885 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (92 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 548852020-09-05T02:42:0005 September 2020 02:42:00
[Table view]10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Manual Reactor Trip and Automatic Safety Injection 2020-09-05T02:42:00 | |