During the evaluation of
tornado missile vulnerabilities and the potential impacts to Technical Specification (TS) plant equipment, it was concluded that the following
SSCs [Structures, Systems, and Components] were vulnerable to
tornado generated missiles:
The Turbine Driving Auxiliary Feedwater (TDAFW) pump exhaust vent is not adequately protected from tornado generated missiles. A tornado could generate missiles capable of striking the exhaust piping on the Turbine Driven Auxiliary Feedwater Pump, crimping the piping resulting in reduced flow capacity and rendering the TDAFW pump inoperable.
The Condensate Storage Tank (CST) vents are not adequately protected from tornado generated missiles. A tornado generated missile could strike the vent piping rendering it unable to relieve vacuum on the top of the CST and allow adequate water flow to the Auxiliary Feedwater Pumps and rendering the CST inoperable.
These conditions are reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v)(D) for 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 mitigate the consequences of an accident.
This condition is being addressed in accordance with
EGM-15-002 and
DSS-ISG-2016-01 (
enforcement discretion and interim guidance documents). The NRC Resident lnspector has been notified.
