Event Notification Report for October 08, 2013
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
10/07/2013 - 10/08/2013
Power Reactor
Event Number: 49419
Facility: COMANCHE PEAK
Region: 4 State: TX
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JOHN RASMUSSEN
HQ OPS Officer: BILL HUFFMAN
Region: 4 State: TX
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JOHN RASMUSSEN
HQ OPS Officer: BILL HUFFMAN
Notification Date: 10/08/2013
Notification Time: 15:42 [ET]
Event Date: 10/08/2013
Event Time: 12:40 [CDT]
Last Update Date: 10/08/2013
Notification Time: 15:42 [ET]
Event Date: 10/08/2013
Event Time: 12:40 [CDT]
Last Update Date: 10/08/2013
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):
MARK HAIRE (R4DO)
MARK HAIRE (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
POSTULATED HOT SHORT FIRE EVENT THAT COULD ADVERSELY IMPACT SAFE SHUTDOWN EQUIPMENT
"A review of industry operating experience regarding the impact of unfused Direct Current (DC) ammeter circuits in the control room has determined the described condition to be applicable to Comanche Peak Nuclear Power Plant resulting in a potentially unanalyzed condition with respect to 10CFR50 Appendix R analysis requirements. The original plant wiring design and associated analysis for the Class 1 E batteries control room ampere indications do not include overcurrent protection features to limit the fault current.
"In the postulated event, a fire in the control room could cause one of the ammeter wires to hot short to the ground plane. Simultaneously, the fire causes another DC wire from the opposite polarity on the same battery to also hot short to the ground plane. This could cause a ground loop through the unprotected ammeter wiring. This event could result in excessive current flow (heating) in the ammeter wiring to the point of causing a secondary fire in the raceway system. The secondary fire could adversely affect safe shutdown equipment and potentially cause the loss of the ability to conduct a safe shutdown as required by 10CFR50 Appendix R.
"This condition is reportable in accordance with 10CFR50.72(b)(3)(ii)(B) as an unanalyzed condition. Compensatory measures (fire watches) have been implemented for affected areas of the plant."
The licensee has notified the NRC Resident Inspector.
See related Event #49411.
"A review of industry operating experience regarding the impact of unfused Direct Current (DC) ammeter circuits in the control room has determined the described condition to be applicable to Comanche Peak Nuclear Power Plant resulting in a potentially unanalyzed condition with respect to 10CFR50 Appendix R analysis requirements. The original plant wiring design and associated analysis for the Class 1 E batteries control room ampere indications do not include overcurrent protection features to limit the fault current.
"In the postulated event, a fire in the control room could cause one of the ammeter wires to hot short to the ground plane. Simultaneously, the fire causes another DC wire from the opposite polarity on the same battery to also hot short to the ground plane. This could cause a ground loop through the unprotected ammeter wiring. This event could result in excessive current flow (heating) in the ammeter wiring to the point of causing a secondary fire in the raceway system. The secondary fire could adversely affect safe shutdown equipment and potentially cause the loss of the ability to conduct a safe shutdown as required by 10CFR50 Appendix R.
"This condition is reportable in accordance with 10CFR50.72(b)(3)(ii)(B) as an unanalyzed condition. Compensatory measures (fire watches) have been implemented for affected areas of the plant."
The licensee has notified the NRC Resident Inspector.
See related Event #49411.
Power Reactor
Event Number: 49420
Facility: MILLSTONE
Region: 1 State: CT
Unit: [] [2] []
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: ANGELO LEONE
HQ OPS Officer: DONG HWA PARK
Region: 1 State: CT
Unit: [] [2] []
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: ANGELO LEONE
HQ OPS Officer: DONG HWA PARK
Notification Date: 10/08/2013
Notification Time: 16:31 [ET]
Event Date: 10/08/2013
Event Time: 14:26 [EDT]
Last Update Date: 10/08/2013
Notification Time: 16:31 [ET]
Event Date: 10/08/2013
Event Time: 14:26 [EDT]
Last Update Date: 10/08/2013
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
JAMES NOGGLE (R1DO)
JAMES NOGGLE (R1DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
STACK RADIATION MONITOR REMOVED FROM SERVICE FOR PLANNED MAINTENANCE
The Millstone Power Station Unit 2 Stack Radiation Monitor, RM-8169 is being removed from service for preplanned maintenance. The radiation monitor is estimated to be out of service for approximately 6 hours. This action is reportable as a loss of assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii).
The NRC Resident Inspector has been notified. State and local authorities were notified by the licensee.
The Millstone Power Station Unit 2 Stack Radiation Monitor, RM-8169 is being removed from service for preplanned maintenance. The radiation monitor is estimated to be out of service for approximately 6 hours. This action is reportable as a loss of assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii).
The NRC Resident Inspector has been notified. State and local authorities were notified by the licensee.