Identification of key parameters of magnetite deposition on steam generator surfaces – modeling and preliminary experiments

The present paper describes a sensitivity study of the fundamental parameters of a deposition model for magnetite on secondary circuit surfaces in terms of their relative influence on the individual steps of the overall process. First, a description of the processes of particle deposition and detachment is presented, emphasizing the role of Van der Waals and electrostatic forces, as well as the roughness of both particle and substrate. Particular attention is paid to the influence of water chemistry on these interaction forces. Further, the paper attempts to propose a mechanism for deposit consolidation modelled as a crystallization reaction and discusses the sensitivity of parameters of a Johnson-Mehl-Kolmogorov-Avrami approach to such a reaction. In the experimental part of the paper, preliminary results on the influence of temperature and water chemistry on the one of the key parameters – the zeta-potential of magnetite – are described and discussed. The results are successfully reproduced using a recent model from the literature on compatible media.