Event Notification Report for March 04, 2016
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/03/2016 - 03/04/2016
EVENT NUMBERS
51769
Power Reactor
Event Number: 51769
Facility: BRUNSWICK
Region: 2 State: NC
Unit: [1] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: KEN KALEY
HQ OPS Officer: DONALD NORWOOD
Region: 2 State: NC
Unit: [1] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: KEN KALEY
HQ OPS Officer: DONALD NORWOOD
Notification Date: 03/04/2016
Notification Time: 20:02 [ET]
Event Date: 03/04/2016
Event Time: 12:35 [EST]
Last Update Date: 03/04/2016
Notification Time: 20:02 [ET]
Event Date: 03/04/2016
Event Time: 12:35 [EST]
Last Update Date: 03/04/2016
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
MARVIN SYKES (R2DO)
MARVIN SYKES (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Refueling | 0 | Refueling |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
EMERGENCY DIESEL GENERATOR DECLARED INOPERABLE
"On March 3, 2016, during restoration of power to a Unit 1 electrical bus following planned work, an error in the restoration sequence resulted in an invalid auto-start signal to Emergency Diesel Generators (EDGs) 1, 2, 3 and 4. EDG 1 was out-of-service under clearance to support Unit 1 refueling outage modifications and maintenance and, as such, did not start. EDGs 2 and 4 auto-started as designed. However, EDG 3 failed to auto-start. At 1235 EST on March 4, 2016, EDG 3 was declared inoperable when troubleshooting identified a broken fuse block connection in the EDG 3 auto-start circuitry, which would have prevented a Technical Specification (TS) required auto-start of EDG 3. This condition concurrent with EDG 1 out-of-service would have precluded emergency power supply to emergency busses needed to mitigate the consequences of an accident.
"Technical Specification 3.8.1, Required Action D.3, requires declaring the required features supported by the inoperable EDG 3 inoperable when the redundant required features are inoperable. As a result, both required Conventional Service Water (CSW) pumps were declared inoperable at 1635 EST on March 4, 2016. This also required declaring both Control Building Instrument Air Compressors inoperable. As a result, both Control Room Emergency Ventilation (CREV) subsystems and all three Control Building Air Conditioners were declared inoperable at 1635 EST on March 4, 2016.
"The above conditions are reportable under 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident.
"This event did not result in any adverse impact to the health and safety of the public.
"The risk significance of this event is considered to be low. Both EDG 2 and EDG 4 were available and protected, along with the supplemental diesel generator and offsite electrical sources. Except for the periods of time for repair activities and post-repair testing, EDG 3 remained available via manual start. Actions were taken to protect other redundant safety systems and additional defense-in-depth was provided.
"EDG 3 was restored to Operable status March 4, 2016 at 1834 EST and this has restored the safety functions of the above mentioned systems."
The licensee notified the NRC Resident Inspector.
"On March 3, 2016, during restoration of power to a Unit 1 electrical bus following planned work, an error in the restoration sequence resulted in an invalid auto-start signal to Emergency Diesel Generators (EDGs) 1, 2, 3 and 4. EDG 1 was out-of-service under clearance to support Unit 1 refueling outage modifications and maintenance and, as such, did not start. EDGs 2 and 4 auto-started as designed. However, EDG 3 failed to auto-start. At 1235 EST on March 4, 2016, EDG 3 was declared inoperable when troubleshooting identified a broken fuse block connection in the EDG 3 auto-start circuitry, which would have prevented a Technical Specification (TS) required auto-start of EDG 3. This condition concurrent with EDG 1 out-of-service would have precluded emergency power supply to emergency busses needed to mitigate the consequences of an accident.
"Technical Specification 3.8.1, Required Action D.3, requires declaring the required features supported by the inoperable EDG 3 inoperable when the redundant required features are inoperable. As a result, both required Conventional Service Water (CSW) pumps were declared inoperable at 1635 EST on March 4, 2016. This also required declaring both Control Building Instrument Air Compressors inoperable. As a result, both Control Room Emergency Ventilation (CREV) subsystems and all three Control Building Air Conditioners were declared inoperable at 1635 EST on March 4, 2016.
"The above conditions are reportable under 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident.
"This event did not result in any adverse impact to the health and safety of the public.
"The risk significance of this event is considered to be low. Both EDG 2 and EDG 4 were available and protected, along with the supplemental diesel generator and offsite electrical sources. Except for the periods of time for repair activities and post-repair testing, EDG 3 remained available via manual start. Actions were taken to protect other redundant safety systems and additional defense-in-depth was provided.
"EDG 3 was restored to Operable status March 4, 2016 at 1834 EST and this has restored the safety functions of the above mentioned systems."
The licensee notified the NRC Resident Inspector.