Event Notification Report for June 05, 2016
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
06/04/2016 - 06/05/2016
EVENT NUMBERS
51982
Power Reactor
Event Number: 51982
Facility: WATTS BAR
Region: 2 State: TN
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: MICHAEL BOTTORFF
HQ OPS Officer: DONG HWA PARK
Region: 2 State: TN
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: MICHAEL BOTTORFF
HQ OPS Officer: DONG HWA PARK
Notification Date: 06/05/2016
Notification Time: 16:22 [ET]
Event Date: 06/05/2016
Event Time: 12:27 [EDT]
Last Update Date: 06/05/2016
Notification Time: 16:22 [ET]
Event Date: 06/05/2016
Event Time: 12:27 [EDT]
Last Update Date: 06/05/2016
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(A) - ECCS INJECTION 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)(A) - ECCS INJECTION 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
OMAR LOPEZ (R2DO)
OMAR LOPEZ (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 13 | Power Operation | 0 | Hot Standby |
REACTOR TRIP AND ECCS ACTUATION CAUSED BY TURBINE GOVERNOR VALVE FAILURE
"On June 5, 2016 at 1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant (WBN) Unit 2 was in MODE 1 at approximately 12.5% power when a safety injection actuation occurred, followed by an automatic reactor protection system (RPS) trip. Preliminary data suggests that the #1 high pressure turbine governor valve failed open causing a steam header pressure rate of decrease safety injection [SI] actuation signal. As designed, the safety injection actuation caused both trains of the shared Emergency Gas Treatment System (EGTS) to align to Unit 2, requiring WBN Unit 1 to enter Technical Specification (TS) LCO 3.0.3 at 1227 [EDT]. Also as designed, Unit 1 annulus pressure momentarily increased, causing operation personnel to enter LCO 3.6.15 Condition B at 1240 [EDT]. At 1242 [EDT], after annulus pressure normalized, operations personnel exited LCO 3.6.15. At 1245 [EDT], Operations personnel secured safety injection and Unit 2 was stabilized in MODE 3 at normal operating pressure and temperature. By 1349 [EDT], Unit 1 Operations personnel had restored both trains of EGTS to standby readiness, and exited TS 3.0.3. No primary safety barriers (RCS, containment and fuel clad) were challenged and no primary or secondary safety or relief valves actuated during the event. The Unit 2 plant trip was uncomplicated and safety equipment operated as expected.
"Unit 2 is stable in Mode 3 at normal operating temperature and pressure, in normal shutdown power alignment. Unit 1 is stable in Mode 1 at 100% power.
"The Senior Resident Inspector has been notified of this event."
The MSIVs are shut with the steam generators (SG) discharging steam using the atmospheric dump valves. There is no primary to secondary leakage. Motor driven AFW pumps are running to maintain SG levels. RCS pressure remained above ECCS (Emergency Core Cooling System) discharge pressure.
"On June 5, 2016 at 1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant (WBN) Unit 2 was in MODE 1 at approximately 12.5% power when a safety injection actuation occurred, followed by an automatic reactor protection system (RPS) trip. Preliminary data suggests that the #1 high pressure turbine governor valve failed open causing a steam header pressure rate of decrease safety injection [SI] actuation signal. As designed, the safety injection actuation caused both trains of the shared Emergency Gas Treatment System (EGTS) to align to Unit 2, requiring WBN Unit 1 to enter Technical Specification (TS) LCO 3.0.3 at 1227 [EDT]. Also as designed, Unit 1 annulus pressure momentarily increased, causing operation personnel to enter LCO 3.6.15 Condition B at 1240 [EDT]. At 1242 [EDT], after annulus pressure normalized, operations personnel exited LCO 3.6.15. At 1245 [EDT], Operations personnel secured safety injection and Unit 2 was stabilized in MODE 3 at normal operating pressure and temperature. By 1349 [EDT], Unit 1 Operations personnel had restored both trains of EGTS to standby readiness, and exited TS 3.0.3. No primary safety barriers (RCS, containment and fuel clad) were challenged and no primary or secondary safety or relief valves actuated during the event. The Unit 2 plant trip was uncomplicated and safety equipment operated as expected.
"Unit 2 is stable in Mode 3 at normal operating temperature and pressure, in normal shutdown power alignment. Unit 1 is stable in Mode 1 at 100% power.
"The Senior Resident Inspector has been notified of this event."
The MSIVs are shut with the steam generators (SG) discharging steam using the atmospheric dump valves. There is no primary to secondary leakage. Motor driven AFW pumps are running to maintain SG levels. RCS pressure remained above ECCS (Emergency Core Cooling System) discharge pressure.