Event Notification Report for February 09, 2007
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
02/08/2007 - 02/09/2007
EVENT NUMBERS
43159
Power Reactor
Event Number: 43159
Facility: BROWNS FERRY
Region: 2 State: AL
Unit: [] [] [3]
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: MATTHEW RASMUSSEN
HQ OPS Officer: JOE O'HARA
Region: 2 State: AL
Unit: [] [] [3]
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: MATTHEW RASMUSSEN
HQ OPS Officer: JOE O'HARA
Notification Date: 02/09/2007
Notification Time: 16:32 [ET]
Event Date: 02/09/2007
Event Time: 12:08 [CST]
Last Update Date: 02/09/2007
Notification Time: 16:32 [ET]
Event Date: 02/09/2007
Event Time: 12:08 [CST]
Last Update Date: 02/09/2007
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(A) - ECCS INJECTION 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
10 CFR Section:
50.72(b)(2)(iv)(A) - ECCS INJECTION 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
CAROLYN EVANS (R2)
TIM McGINTY (NRR)
JEFFREY CRUZ (IRD)
CAROLYN EVANS (R2)
TIM McGINTY (NRR)
JEFFREY CRUZ (IRD)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | A/R | Y | 100 | Power Operation | 0 | Hot Shutdown |
REACTOR SCRAM DUE TO LOW REACTOR WATER LEVEL
"At 1208[CST] on 02/09/2007 with Unit 3 at 100% power, an automatic reactor scram (RPS) was received due to lowering water level. Loss of water level was due to lowering condensate flow which in turn caused a reduction in feedwater flow. Reactor water level lowered to -45 Inches. High Pressure Coolant Injection and Reactor Core Isolation Cooling systems initiated as expected. Additionally, the Recirculation Pump breakers tripped as expected. All expected Primary Containment Isolations, Group 2 (RHR Shutdown Cooling), Group 3 (RWCU), Group 6 (Ventilation), and Group 8 (TIP) were received along with the auto start of Control Room Emergency Ventilation (CREV) and 3 Standby Gas Treatment (SBGT) trains. Unit 2 was at 80% power and was unaffected by the event. Investigation has been initiated as to the cause of the lowering condensate flow.
"This event is reportable as a 4-hour and 8-hour non-emergency notification in accordance with 10 CFR50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical, 10 CFR 5172(b)(3)(Iv)(A) as any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(Iv)(b), and 10 CFR 50.72(b)(2)(Iv)(A) as any event or condition that results or should have resulted In ECCS discharging to the reactor coolant system.
"All control rods fully inserted, the electrical grid is stable. Decay heat is being removed via the turbine bypass valves to the main condenser. The licensee has notified the NRC Senior Resident Inspector."
There was no excessive cooldown rate during the injection phase as cooldown rate did not exceed 100 degrees Fahrenheit. Total injection time for both HPCI and RCIC systems was approximately 2 minutes which resulted in approximately 13,000 gallons of coolant from the condensate storage tank (CST) entering the reactor vessel. Primary plant temperature and pressure are 531 degrees Fahrenheit and 928 psig, respectively.
"At 1208[CST] on 02/09/2007 with Unit 3 at 100% power, an automatic reactor scram (RPS) was received due to lowering water level. Loss of water level was due to lowering condensate flow which in turn caused a reduction in feedwater flow. Reactor water level lowered to -45 Inches. High Pressure Coolant Injection and Reactor Core Isolation Cooling systems initiated as expected. Additionally, the Recirculation Pump breakers tripped as expected. All expected Primary Containment Isolations, Group 2 (RHR Shutdown Cooling), Group 3 (RWCU), Group 6 (Ventilation), and Group 8 (TIP) were received along with the auto start of Control Room Emergency Ventilation (CREV) and 3 Standby Gas Treatment (SBGT) trains. Unit 2 was at 80% power and was unaffected by the event. Investigation has been initiated as to the cause of the lowering condensate flow.
"This event is reportable as a 4-hour and 8-hour non-emergency notification in accordance with 10 CFR50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical, 10 CFR 5172(b)(3)(Iv)(A) as any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(Iv)(b), and 10 CFR 50.72(b)(2)(Iv)(A) as any event or condition that results or should have resulted In ECCS discharging to the reactor coolant system.
"All control rods fully inserted, the electrical grid is stable. Decay heat is being removed via the turbine bypass valves to the main condenser. The licensee has notified the NRC Senior Resident Inspector."
There was no excessive cooldown rate during the injection phase as cooldown rate did not exceed 100 degrees Fahrenheit. Total injection time for both HPCI and RCIC systems was approximately 2 minutes which resulted in approximately 13,000 gallons of coolant from the condensate storage tank (CST) entering the reactor vessel. Primary plant temperature and pressure are 531 degrees Fahrenheit and 928 psig, respectively.