Ni-ferrite Surface Property Measurements at Elevated Temperature Conditions

In nuclear plants with Ni alloy components, reactor coolant contains circulating nano- to micrometer-sized particles of Ni-Fe oxide (Ni-ferrite).  Deposition of these particles on wetted surfaces reduces heat transfer, degrades performance of plant components, and may cause elevated radiation levels in reactor coolant piping.  The transport and deposition of particles are controlled by particle-particle and particle-surface interactions which depend on coolant chemistry, thermal hydraulic conditions, and the surface properties of the materials.  There are few direct measurements of surface properties or of particle-particle or particle-surface interactions at elevated temperatures (150-350 °C), and in some cases, for incompletely characterized particulate material.  The Naval Nuclear Laboratory (NNL) is seeking accurate, high temperature surface property and interaction measurements of well-characterized particles and surfaces under reactor plant conditions to predict the transport and deposition of these materials.