14:10 Dec 5, 2019
Fire Door Discovered Unlatched
The following was received via email from Cooper Nuclear Station:
At 0810 [CST], on 12/5/19, Operations personnel discovered BLDG-DOOR-R209, FIRE DOOR BETWEEN CRITICAL SWITCHGEAR ROOMS F & G, was unlatched. The door was immediately latched upon discovery. Based on door logs, the door separating the two critical switchgear rooms was inadvertently left unlatched for approximately 5 minutes. This door is a Steam Exclusion Boundary (SEB) door. It is required to be closed and latched when the Auxiliary Steam Boiler is in service due to Auxiliary Steam piping passing through Critical Switchgear Room 'G'. If a steam line break was to occur with the door unlatched, steam could render both Critical Switchgear busses inoperable.
This is being reported under 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, and 10 CFR 50.72(b)(3)(v), Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (B) remove residual heat and to (D) mitigate consequences of an accident.
There was no impact on the health and safety of the public or plant personnel.
The door closes automatically and appeared to have been left unlatched by the last person passing through. The door was tested and latches as required.The licensee notified the NRC Resident Inspector.
Nebraska (NRC Region 4)
|10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition|
10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat
10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
|Time - Person (Reporting Time:+1.88 h0.0783 days <br />0.0112 weeks <br />0.00258 months <br />)|
16:03 Dec 5, 2019
|NRC Officer:||Kerby Scales|
|Last Updated:||Dec 5, 2019|
|54425 - NRC Website|