Abstract: An illustrative embodiment of the invention eliminates the circumferential thermal stresses found in a feedwater inlet nozzle of a once-through-vapor generator that are caused by the presence of steam in the nozzle during a low flow load condition. Specifically, The cold inlet feedwater is directed upwardly to fill and overflow the nozzle conduit and prevent steam entrance and collection in the nozzle, and then, impinges on a shroud which re-directs the flow downward into fluid flow contact with the nozzle conduit and through the vapor generator.