A detailed model of the transport processes that produce concentrated solutions locally in pressurized water reactor steam generators has been developed. The model describes the heat, mass, and momentum transfer processes that occur in porous deposits such as those found in tube support and tubesheet crevices and in the sludge pile on top of the tubesheet. The model is used to predict the concentration of a species in the pore solution as a function of time and at steady state, and the model predictions are compared to available experimental data. Several parametric studies were performed with the model to identify important design and operating parameters.