Event Notification Report for July 21, 2019
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/20/2019 - 07/21/2019
EVENT NUMBERS
54176
54176
Power Reactor
Event Number: 54176
Facility: COOK
Region: 3 State: MI
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: PERRY GRAHAM
HQ OPS Officer: RICHARD SMITH
Region: 3 State: MI
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: PERRY GRAHAM
HQ OPS Officer: RICHARD SMITH
Notification Date: 07/21/2019
Notification Time: 12:08 [ET]
Event Date: 07/21/2019
Event Time: 08:26 [EDT]
Last Update Date: 07/21/2019
Notification Time: 12:08 [ET]
Event Date: 07/21/2019
Event Time: 08:26 [EDT]
Last Update Date: 07/21/2019
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
RHEX EDWARDS (R3DO)
RHEX EDWARDS (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | M/R | Y | 17 | Power Operation | 0 | Hot Standby |
MANUAL REACTOR TRIP DUE NON-ESSENTIAL SERVICE WATER SYSTEM DEGRADED CONDITION
"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.
"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.