Event Notification Report for July 28, 2013
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/27/2013 - 07/28/2013
EVENT NUMBERS
49220
Power Reactor
Event Number: 49220
Facility: COOK
Region: 3 State: MI
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DEAN BRUCK
HQ OPS Officer: PETE SNYDER
Region: 3 State: MI
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DEAN BRUCK
HQ OPS Officer: PETE SNYDER
Notification Date: 07/28/2013
Notification Time: 13:43 [ET]
Event Date: 07/28/2013
Event Time: 10:18 [EDT]
Last Update Date: 07/29/2013
Notification Time: 13:43 [ET]
Event Date: 07/28/2013
Event Time: 10:18 [EDT]
Last Update Date: 07/29/2013
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):
PATTY PELKE (R3DO)
PATTY PELKE (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | M/R | Y | 100 | Power Operation | 0 | Hot Standby |
MANUAL REACTOR TRIP FOLLOWING SECONDARY PLANT TRANSIENT
"On July 28, 2013, at 1018 EDT, DC Cook Unit 2 Reactor was manually tripped due to lowering steam generator level caused by an automatic trip of the west main feed pump. The west main feed pump tripped on low suction pressure resulting from a secondary plant transient. The cause of the secondary transient is still under investigation.
"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 (8) hour report.
"The DC Cook Sr. Resident NRC Inspector has been notified.
"The electrical grid is stable and Unit 2 is being supplied by offsite power. All control rods fully inserted. Decay heat is being removed via steam dumps to the main condenser. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the post trip review. No radioactive release is in progress as a result of this event."
There was no affect on Unit 1.
* * * UPDATE FROM DEAN BRUCK TO DONALD NORWOOD AT 1753 EDT ON 7/29/13 * * *
"Additional information received determined the Turbine Driven Auxiliary Feedwater Pump discharge valve to Steam Generator #2 did not position, as required, following the reactor trip. The affected discharge valve opened as expected during pump start. The valve closed instead of throttling to the intermediate position upon subsequent high flow demand. Feedwater flow to Steam Generator #2 was maintained by the East Motor Driven Auxiliary Feedwater Pump.
"The NRC Resident Inspector has been notified of this update."
Notified R3DO (Orth).
"On July 28, 2013, at 1018 EDT, DC Cook Unit 2 Reactor was manually tripped due to lowering steam generator level caused by an automatic trip of the west main feed pump. The west main feed pump tripped on low suction pressure resulting from a secondary plant transient. The cause of the secondary transient is still under investigation.
"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 (8) hour report.
"The DC Cook Sr. Resident NRC Inspector has been notified.
"The electrical grid is stable and Unit 2 is being supplied by offsite power. All control rods fully inserted. Decay heat is being removed via steam dumps to the main condenser. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the post trip review. No radioactive release is in progress as a result of this event."
There was no affect on Unit 1.
* * * UPDATE FROM DEAN BRUCK TO DONALD NORWOOD AT 1753 EDT ON 7/29/13 * * *
"Additional information received determined the Turbine Driven Auxiliary Feedwater Pump discharge valve to Steam Generator #2 did not position, as required, following the reactor trip. The affected discharge valve opened as expected during pump start. The valve closed instead of throttling to the intermediate position upon subsequent high flow demand. Feedwater flow to Steam Generator #2 was maintained by the East Motor Driven Auxiliary Feedwater Pump.
"The NRC Resident Inspector has been notified of this update."
Notified R3DO (Orth).