Abstract
Most corrosion products carried by the feedwater ultimately set down on the steam generator tubes to form fouling deposits. These deposits impact the thermal efficiency of the heat exchanger. They usually hamper the heat transfer from the reactor coolant (primary circuit) to the feedwater (secondary circuit). But under certain circumstances, they may even promote it. The main objective of this study is to develop a comprehensive steam generator heat transfer model which takes into account the phenomena and processes that characterize the fouling deposits. The model is made up of two parts: a fractal model which estimates the micro-characteristics of the deposits and a heat transfer model which simulates the thermal conduction and boiling phenomena. A sensitivity analysis is performed to determine the most influential parameters, i.e., the deposit thickness or the deposit porosity. It is found that thin and porous deposit layers promote heat transfer whereas dense and thick deposit layers deteriorate it. The limits of the model are discussed and future work for its improvement is suggested.
