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Event Notification Report for August 31, 2019

U.S. Nuclear Regulatory Commission
Operations Center

EVENT REPORTS FOR
08/30/2019 - 08/31/2019

EVENT NUMBERS
54252
Power Reactor
Event Number: 54252
Facility: WATTS BAR
Region: 2     State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DAVID ALLEN
HQ OPS Officer: OSSY FONT
Notification Date: 09/01/2019
Notification Time: 00:09 [ET]
Event Date: 08/31/2019
Event Time: 20:55 [EDT]
Last Update Date: 09/01/2019
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
Person (Organization):
STEVE ROSE (R2DO)
Power Reactor Unit Info
Unit SCRAM Code RX Crit Initial PWR Initial RX Mode Current PWR Current RX Mode
1 M/R Y 100 Power Operation 0 Hot Standby
Event Text
MANUAL TRIP DUE TO LOSS OF STEAM GENERATOR LEVEL CONTROL

"While operating at 100 percent power, the Watts Bar Unit 1 reactor was manually tripped at 2055 EDT on August 31, 2019 due to loss of steam generator #2 level control. The trip was not complex. All control and shutdown bank rods inserted properly in response to the manual reactor trip. All safety systems, including Auxiliary Feedwater, actuated as designed. Operations responded and stabilized the plant. Decay heat is being removed by the Auxiliary Feedwater and the Steam Dump System.

"Unit 2 is not affected.

"The cause of the loss of steam generator water level control is being investigated.

"The manual actuation of the Reactor Protection System (RPS) is being reported as a four hour report under 10 CFR 50.72 (b)(2)(iv)(B). The automatic actuation of the Auxiliary Feedwater System (an engineered safety feature) is being reported as an eight hour report under 10 CFR 50.72 (b)(3)(iv)(A).

"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector was notified."