A system includes a radiation detector array configured to direct a field of view toward multiple conduits within a fluid flow path from a turbine into a heat exchanger. The radiation detector array is configured to output a signal indicative of a multi-dimensional temperature profile of the fluid flow path based on thermal radiation emitted by the conduits. The system also includes a controller communicatively coupled to the radiation detector array. The controller is configured to determine a temperature variation across the fluid flow path based on the signal, and to compare the temperature variation to a threshold value.