Event Notification Report for February 10, 2021
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
02/09/2021 - 02/10/2021
Power Reactor
Event Number: 55098
Facility: Cooper
Region: 4 State: NE
Unit: [1] [] []
RX Type: [1] GE-4
NRC Notified By: Aric Harris
HQ OPS Officer: Joanna Bridge
Notification Date: 02/09/2021
Notification Time: 10:35 [ET]
Event Date: 02/09/2021
Event Time: 01:53 [CST]
Last Update Date: 02/09/2021
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(v)(C) - Pot Uncntrl Rad Rel
50.72(b)(3)(v)(D) - Accident Mitigation
Person (Organization):
DIXON, JOHN (R4)
Power Reactor Unit Info
| Unit |
SCRAM Code |
RX Crit |
Initial PWR |
Initial RX Mode |
Current PWR |
Current RX Mode |
| 1 |
N |
Y |
100 |
Power Operation |
100 |
Power Operation |
Event Text
CONTROL RELEASE OF RADIOACTIVE MATERIAL AND ACCIDENT MITIGATION
"On February 9, 2021, at 0153 CST, Cooper Nuclear Station experienced a spike in Secondary Containment differential pressure which exceeded the Technical Specifications Surveillance Requirements 3.6.4.1.1 limit of -0.25 inches of water gauge. Secondary Containment differential pressure oscillated coincident with barometric pressure oscillations. Three additional spikes occurred which exceed the Technical Specification limit. The duration of each spike was less than one minute. The last spike occurred at 0232 CST. Secondary Containment differential pressure has restored to Technical Specification limits and further investigation is ongoing.
"This unplanned Secondary Containment inoperability constitutes a condition reportable under 10CFR50.72(b)(3)(v)(C) and (D), "An event or condition that at the time of discovery could have prevented the fulfillment of the safety function of [Structures, Systems, and Components] SSCs that are needed to control the release of radioactive material and mitigate the consequences of an accident.
"The NRC Senior Resident Inspector has been informed."
Power Reactor
Event Number: 55099
Facility: Robinson
Region: 2 State: SC
Unit: [2] [] []
RX Type: [2] W-3-LP
NRC Notified By: Michael Smith
HQ OPS Officer: Joanna Bridge
Notification Date: 02/09/2021
Notification Time: 11:00 [ET]
Event Date: 02/09/2021
Event Time: 08:00 [EST]
Last Update Date: 02/09/2021
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(2)(xi) - Offsite Notification
Person (Organization):
MILLER, MARK (R2)
Power Reactor Unit Info
| Unit |
SCRAM Code |
RX Crit |
Initial PWR |
Initial RX Mode |
Current PWR |
Current RX Mode |
| 2 |
N |
Y |
100 |
Power Operation |
100 |
Power Operation |
Event Text
OFFSITE NOTIFICATION DUE TO AN INADVERTENT ACTUATION OF EMERGENCY SIRENS
"At approximately 0800 on February 9, 2021, thirty-one (31) H.B. Robinson Nuclear Plant Offsite Emergency Notification sirens in Darlington County, SC were inadvertently actuated. The Darlington County Emergency Services and South Carolina Emergency Management Division were promptly notified. The actuation lasted for three (3) minutes at full volume. The cause of the actuation is under investigation at this time.
"Capability to notify the public was never degraded during the inadvertent actuation. All Emergency Notification sirens remain in service.
"This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report.
"The NRC Resident Inspector has been notified."
A local news agency did report about the alarms sounding and reported that there was no concern at the site.