Event Notification Report for January 30, 2018
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
01/29/2018 - 01/30/2018
EVENT NUMBERS
53188
Power Reactor
Event Number: 53188
Facility: GRAND GULF
Region: 4 State: MS
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: RALPH FLICKINGER
HQ OPS Officer: DONG HWA PARK
Region: 4 State: MS
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: RALPH FLICKINGER
HQ OPS Officer: DONG HWA PARK
Notification Date: 01/30/2018
Notification Time: 21:56 [ET]
Event Date: 01/30/2018
Event Time: 18:22 [CST]
Last Update Date: 01/30/2018
Notification Time: 21:56 [ET]
Event Date: 01/30/2018
Event Time: 18:22 [CST]
Last Update Date: 01/30/2018
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):
RICK DEESE (R4DO)
RICK DEESE (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 91 | Power Operation | 0 | Hot Shutdown |
MANUAL REACTOR SCRAM DUE TO MAIN TURBINE LOAD OSCILLATIONS
"On 1/30/2018 at 1750 [CST], the Reactor Pressure Control Malfunctions ONEP [Off Normal Event Procedure] was entered due to main turbine load oscillations of approximately 30 MWe peak to peak. At 1822 [CST], a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown due to continued main turbine load oscillations.
"Reactor SCRAM ONEP, Turbine Trip ONEP, and EP-2 were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 933 psig using main turbine bypass valves.
"Reactor Water Level 3 (11.4 inches) was reached which is the setpoint for Group 2 (RHR to Radwaste Isolation) and Group 3 (Shutdown Cooling Isolation). No valve isolated in these systems due to all isolation valves in these groups being in their normally closed position. The lowest Reactor Water level reached was -36 inches wide range.
"No other safety system actuations occurred and all systems performed as designed.
"That event is being reported under 10CFR 50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the Reactor Protection System (RPS), when the reactor is critical and also reported under 10CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS."
The MSIVs are open with decay heat being removed via steam to the main condenser using the bypass valves. Off site power is stable, and the plant is in a normal shutdown electrical lineup. RCIC (Reactor Core Isolation Cooling) was out of service for maintenance, and the reactor water level did not reach the system activation level. The cause of the main turbine load oscillations being investigated.
The licensee notified the NRC Resident Inspector.
"On 1/30/2018 at 1750 [CST], the Reactor Pressure Control Malfunctions ONEP [Off Normal Event Procedure] was entered due to main turbine load oscillations of approximately 30 MWe peak to peak. At 1822 [CST], a manual reactor scram was inserted by placing the Reactor Mode Switch in Shutdown due to continued main turbine load oscillations.
"Reactor SCRAM ONEP, Turbine Trip ONEP, and EP-2 were entered. Reactor water level was stabilized at 36 inches narrow range on startup level and reactor pressure stabilized at 933 psig using main turbine bypass valves.
"Reactor Water Level 3 (11.4 inches) was reached which is the setpoint for Group 2 (RHR to Radwaste Isolation) and Group 3 (Shutdown Cooling Isolation). No valve isolated in these systems due to all isolation valves in these groups being in their normally closed position. The lowest Reactor Water level reached was -36 inches wide range.
"No other safety system actuations occurred and all systems performed as designed.
"That event is being reported under 10CFR 50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the Reactor Protection System (RPS), when the reactor is critical and also reported under 10CFR 50.72(b)(3)(iv)(A), as any event or condition that results in actuation of RPS."
The MSIVs are open with decay heat being removed via steam to the main condenser using the bypass valves. Off site power is stable, and the plant is in a normal shutdown electrical lineup. RCIC (Reactor Core Isolation Cooling) was out of service for maintenance, and the reactor water level did not reach the system activation level. The cause of the main turbine load oscillations being investigated.
The licensee notified the NRC Resident Inspector.