Model of the Deposition of Colloidal Crud Particles on the Fuel Elements of Nuclear Power Plants

Experimental data on the adhesion of α-Fe₂O₃ on large ZrO₂ pellets are presented and discussed in terms of the colloidal interactions of the two double layers. The pH dependence of adhesion is thus explained. The relevance of colloidal interactions of this type in reactor conditions is then discussed, through the evaluation of the impact of the existence of a potential barrier to deposition. This is discussed in terms of Beal's model, and the changes in the stopping distance for colloidal particles due to this barrier are evaluated. The influence of pH and particle size on deposition phenomena is also discussed. Predicted values for the deposition coefficient are compared with operational values from the Atucha Nuclear Power Plant.