Event Notification Report for December 16, 2019
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
12/15/2019 - 12/16/2019
EVENT NUMBERS
54446
Power Reactor
Event Number: 54446
Facility: SEQUOYAH
Region: 2 State: TN
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: STEPHEN FRIESE
HQ OPS Officer: JEFF HERRERA
Region: 2 State: TN
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: STEPHEN FRIESE
HQ OPS Officer: JEFF HERRERA
Notification Date: 12/16/2019
Notification Time: 09:12 [ET]
Event Date: 12/16/2019
Event Time: 03:58 [EST]
Last Update Date: 12/16/2019
Notification Time: 09:12 [ET]
Event Date: 12/16/2019
Event Time: 03:58 [EST]
Last Update Date: 12/16/2019
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
BRIAN BONSER (R2DO)
BRIAN BONSER (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 2 | N | Y | 47 | Power Operation | 47 | Power Operation |
EMERGENCY DIESEL GENERATOR AUTOSTART DUE TO LOSS OF POWER TO 1B SHUTDOWN BOARD
"At 0358 EST, on 12/16/2019, with Unit 1 in Mode 1 at 100 [percent] power and Unit 2 in Mode 1 at 47 [percent] power, a valid actuation of the Emergency Diesel Generators (EDG) occurred. The reason for the emergency diesel generator auto start was that the normal feeder breaker from the 1C 6.9KV Unit Board to the 1B-B 6.9KV Shutdown Board (SDBD) tripped due to the breaker's 51G relay actuating causing an under-voltage signal on the 1B-B 6.9KV Shutdown Board. All 4 Emergency Diesel Generators automatically started as designed when the 6.9KV Shutdown Board under-voltage signal was received.
"The 1B-B 6.9KV Shutdown Board was automatically energized from the 1B-B 6.9KV Diesel Generator. All required 6.9KV loads were sequenced back on to the 1B-B 6.9KV Shutdown Board as designed after the board was energized from its emergency diesel generator. The remainder of the electrical system is in normal alignment.
"This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of the Emergency Diesel Generators.
"There was no impact to the health and safety of the public or plant personnel.
"The NRC Senior Resident has been notified."
"At 0358 EST, on 12/16/2019, with Unit 1 in Mode 1 at 100 [percent] power and Unit 2 in Mode 1 at 47 [percent] power, a valid actuation of the Emergency Diesel Generators (EDG) occurred. The reason for the emergency diesel generator auto start was that the normal feeder breaker from the 1C 6.9KV Unit Board to the 1B-B 6.9KV Shutdown Board (SDBD) tripped due to the breaker's 51G relay actuating causing an under-voltage signal on the 1B-B 6.9KV Shutdown Board. All 4 Emergency Diesel Generators automatically started as designed when the 6.9KV Shutdown Board under-voltage signal was received.
"The 1B-B 6.9KV Shutdown Board was automatically energized from the 1B-B 6.9KV Diesel Generator. All required 6.9KV loads were sequenced back on to the 1B-B 6.9KV Shutdown Board as designed after the board was energized from its emergency diesel generator. The remainder of the electrical system is in normal alignment.
"This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of the Emergency Diesel Generators.
"There was no impact to the health and safety of the public or plant personnel.
"The NRC Senior Resident has been notified."