18:00 Feb 12, 2018
En Revision Imported Date 10/14/2019
EN Revision Text: UNANALYZED CONDITION FOR TORNADO GENERATED MISSILES
On February 12, 2018, during evaluation of protection for Technical Specifications (TS) equipment from the damaging effects of tornado generated missiles, Dresden Station identified a non-conforming condition in the plant design such that specific TS equipment is considered to not be adequately protected from tornado generated missiles. Tornado generated missiles could strike the Unit 2, Unit 2/3, and Unit 3 Emergency Diesel Generator main fuel oil tank vents. This could result in crimping of the vents, which would affect the ability of the main fuel oil tanks to perform their function if a tornado would occur.
This condition is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(B) as a condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety and 10 CFR 50.72(b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
This condition is being addressed in accordance with NRC enforcement guidance provided in Enforcement Guidance Memorandum (EGM) 15-002, 'Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' and DSS-ISG-2016-01, 'Clarification of Licensee Actions in Receipt of Enforcement Discretion' per Enforcement Guidance Memorandum EGM 15-002, 'Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' Revision 1. Compensatory measures have been implemented in accordance with these documents.
The NRC Resident Inspector has been informed of this notification.
The purpose of this notification is to retract event notification 53204 made on February 12, 2018, for Dresden Station. Additional review determined that the current design of all three Emergency Diesel Generators and associated Main Fuel Oil Storage Tanks Vents is consistent with the licensing basis for Dresden Station. There was no non-conformance of Dresden's tornado missile protection design, and the EDGs were operable at the time the event notification was made.
The NRC Resident Inspector has been informed of this notification."Notified R3DO (Hills).
Illinois (NRC Region 3)
|10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition|
10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
|Time - Person (Reporting Time:+-4.22 h-0.176 days <br />-0.0251 weeks <br />-0.00578 months <br />)|
13:47 Feb 12, 2018
|NRC Officer:||Mark Abramovitz|
|Last Updated:||Oct 11, 2019|
|53204 - NRC Website|