Event Notification Report for April 30, 2017
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/29/2017 - 04/30/2017
EVENT NUMBERS
52727
Power Reactor
Event Number: 52727
Facility: PERRY
Region: 3 State: OH
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: DAVE DUESING
HQ OPS Officer: STEVEN VITTO
Region: 3 State: OH
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: DAVE DUESING
HQ OPS Officer: STEVEN VITTO
Notification Date: 05/03/2017
Notification Time: 12:59 [ET]
Event Date: 04/30/2017
Event Time: 18:18 [EDT]
Last Update Date: 05/03/2017
Notification Time: 12:59 [ET]
Event Date: 04/30/2017
Event Time: 18:18 [EDT]
Last Update Date: 05/03/2017
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
ROBERT ORLIKOWSKI (R3DO)
ROBERT ORLIKOWSKI (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 74 | Power Operation |
OPEN BYPASS VALVE CAUSES LOSS OF SAFETY FUNCTION
"On April 30, 2017, at 1818 [EDT], the main turbine steam bypass valve #1 partially opened. Power was incrementally lowered. While lowering power the bypass valve would shut and then reopen and power would again be lowered. When power was lowered to approximately 74 percent the bypass valve remained closed. During the transient the reactor protection system (RPS) Turbine Stop Valve Closure and Control Valve Fast Closure trip functions were declared inoperable due to the opening of the bypass valve which affects the bypass setpoint for those RPS trip functions. With the loss of these RPS trip functions a loss of safety function existed intermittently for approximately 37 minutes. The manual reactor trip function and other RPS functions remained operable.
"Both channels of the rod withdrawal limiter (RWL) and the end of cycle reactor recirculation pump trip (EOC-RPT) function were also declared inoperable. These functions are credited in accident analysis, this also resulted in a loss of safety function.
"Currently the bypass valve is closed and the RWL, EOC-RPT and RPS function are operable. Troubleshooting continues to determine the issue with the main turbine that caused the bypass valve to open."
NRC Resident Inspector has been notified.
"On April 30, 2017, at 1818 [EDT], the main turbine steam bypass valve #1 partially opened. Power was incrementally lowered. While lowering power the bypass valve would shut and then reopen and power would again be lowered. When power was lowered to approximately 74 percent the bypass valve remained closed. During the transient the reactor protection system (RPS) Turbine Stop Valve Closure and Control Valve Fast Closure trip functions were declared inoperable due to the opening of the bypass valve which affects the bypass setpoint for those RPS trip functions. With the loss of these RPS trip functions a loss of safety function existed intermittently for approximately 37 minutes. The manual reactor trip function and other RPS functions remained operable.
"Both channels of the rod withdrawal limiter (RWL) and the end of cycle reactor recirculation pump trip (EOC-RPT) function were also declared inoperable. These functions are credited in accident analysis, this also resulted in a loss of safety function.
"Currently the bypass valve is closed and the RWL, EOC-RPT and RPS function are operable. Troubleshooting continues to determine the issue with the main turbine that caused the bypass valve to open."
NRC Resident Inspector has been notified.