Abstract <p>Morphology and thermophysiscal properties of deposits of construction material corrosion products (CMCPs) in steam-generating systems at nuclear power plants (NPPs) and thermal power plants (TPPs) are analyzed. Modern power units utilize high-quality water, and construction materials are essentially steels. Therefore, the main impurities in water are various iron compounds. The deposits of corrosion products usually consist of iron oxides (mainly magnetite). These deposits have a specific capillary-porous structure and considerably affect heat-and-mass transfer during phase transformations. Capillary hydrodynamics also has a pronounced effect on transfer processes. In recent decades, many publications have appeared about the effect of deposit morphology on the concentration of impurities and reagents that control the water chemistry in reactors and steam generators of nuclear power plants. Growing attention has also focused on the temperature conditions of steam-generating surfaces with deposits during heat transfer. The governing effect is produced by the structural features of the deposit layer, such as the diameters of steam and liquid microchannels, density of their distribution over the layer surface, internal characteristics of the boiling process, thermophysical properties of the deposits, thermodynamic and transport properties of water and steam. An analysis of the published data yielded approximating correlations for the diameter of steam microchannels, their distribution density, effective thermal conductivity of the deposit layer, and the maximum water superheating temperature in the deposit layer. Predictions by these correlations satisfactory agree with experimental data. A classification of deposits by their thickness based on the maximum temperature during steam generation at nuclear and thermal power plants is recommended.</p>