Event Notification Report for April 19, 2015
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/18/2015 - 04/19/2015
EVENT NUMBERS
50994
Power Reactor
Event Number: 50994
Facility: PRAIRIE ISLAND
Region: 3 State: MN
Unit: [1] [2] []
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: TOM HOLD
HQ OPS Officer: MARK ABRAMOVITZ
Region: 3 State: MN
Unit: [1] [2] []
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: TOM HOLD
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 04/19/2015
Notification Time: 23:04 [ET]
Event Date: 04/19/2015
Event Time: 17:45 [CDT]
Last Update Date: 04/19/2015
Notification Time: 23:04 [ET]
Event Date: 04/19/2015
Event Time: 17:45 [CDT]
Last Update Date: 04/19/2015
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Person (Organization):
AARON MCCRAW (R3DO)
AARON MCCRAW (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Cold Shutdown | 0 | Cold Shutdown |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
UNANALYZED CONDITION DUE TO NON COMPLIANCE WITH 10 CFR 50 APP R
"On April 19, 2015, it was determined that in the event of an Appendix-R fire in the Control Room/Relay Room, fire induced circuit damage can potentially result in Reactor Coolant Pump's (RCP) restarting. Procedure F5 APP B does not take actions to open RCP DC knife switches as required per Appendix R calculation GEN-PI-026, GEN-PI-054, and GEN-PI-055. Neither unit is currently susceptible to this condition due to the installation of improved RCP seals which allow adequate time to restore seal cooling prior to seal failure. However, the condition has occurred within three years of the time of discovery and is reportable under 10 CFR 50.72(b)(3)(ii)(B).
"The Appendix R analysis requires that manual actions are taken to ensure that the RCPs are tripped and actions are taken to prevent restarting of the RCPs. The RCPs breaker must be verified open at the associated bus and DC knife switches located in the breaker cubicles are to be opened. These actions are required due to fire induced, loss of remote trip (spurious breaker closure) and loss of RCP seal cooling water and loss of Component Cooling (CC) water to the thermal barrier heat exchanger. These actions are required to achieve and maintain Mode 3, Hot Standby in the event of a catastrophic fire that results in the functional loss and/or evacuation of the Control Room/Relay Room.
"Current procedures verify the RCP breakers are open; however, they do not open the DC knife switch and therefore a hot short could result in a RCP restarting. This procedure omission meets the reporting criteria for 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety.
"The protection of the health and safety of the public was not affected by this issue. The licensee has notified the NRC Senior Resident Inspector."
"On April 19, 2015, it was determined that in the event of an Appendix-R fire in the Control Room/Relay Room, fire induced circuit damage can potentially result in Reactor Coolant Pump's (RCP) restarting. Procedure F5 APP B does not take actions to open RCP DC knife switches as required per Appendix R calculation GEN-PI-026, GEN-PI-054, and GEN-PI-055. Neither unit is currently susceptible to this condition due to the installation of improved RCP seals which allow adequate time to restore seal cooling prior to seal failure. However, the condition has occurred within three years of the time of discovery and is reportable under 10 CFR 50.72(b)(3)(ii)(B).
"The Appendix R analysis requires that manual actions are taken to ensure that the RCPs are tripped and actions are taken to prevent restarting of the RCPs. The RCPs breaker must be verified open at the associated bus and DC knife switches located in the breaker cubicles are to be opened. These actions are required due to fire induced, loss of remote trip (spurious breaker closure) and loss of RCP seal cooling water and loss of Component Cooling (CC) water to the thermal barrier heat exchanger. These actions are required to achieve and maintain Mode 3, Hot Standby in the event of a catastrophic fire that results in the functional loss and/or evacuation of the Control Room/Relay Room.
"Current procedures verify the RCP breakers are open; however, they do not open the DC knife switch and therefore a hot short could result in a RCP restarting. This procedure omission meets the reporting criteria for 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety.
"The protection of the health and safety of the public was not affected by this issue. The licensee has notified the NRC Senior Resident Inspector."