A heat transfer system includes a heat exchanger located at least partially within a coolant flowpath. The heat exchanger defines at least in part a first flowpath and a second flowpath, the first flowpath configured to be in fluid communication with the coolant flowpath, and the second flowpath configured to receive a flow of a motive fluid. The heat transfer system further includes a throttling device that is in fluid communication with the second flowpath of the heat exchanger. The heat exchanger receives at least a portion of the flow of the motive fluid from the heat exchanger. The throttling device is also in fluid communication with the coolant flowpath at a location upstream of the heat exchanger for providing the flow of motive fluid to the coolant flowpath at the location upstream of the heat exchanger.