Systems and methods for directing cooling flow into the surge plenum of an exhaust eductor cooling system

An eductor assembly comprises a primary nozzle configured to discharge turbine exhaust gas therefrom. The eductor assembly further comprises a cooler plenum having an inlet and an outlet and a surge plenum at least partially surrounding the cooler plenum and the nozzle, the surge plenum for conducting a surge flow. Cooling air flows through a vent between the cooler plenum and the surge plenum when there is no surge flow.