An analytical model for a thermal contact conductance at the nuclear fuel-clad interface was developed by considering the effect of single heat channel boundary shapes on the conductance and the mechanistic determination of the size of the contact point. The parameters included in this model are the contact size, wavelength, the Meyer hardness of clad, the thermal conductivities and surface roughnesses of fuel and clad, apparent contact pressure and interfacial temperature.
Here, among the linear, sinusoidal and parabolic boundary shapes of the heat channel, the sinusoidal shape was found to give best agreement with the experimental data of the thermal contact conductance. In the determination of the contact size, a relationship of force equilibrium at the interface was established by the assumption of the plastic deformation mode at the contact point. The assumption of the plastic deformation mode was well agreed with experimental data, comparing with that of the elastic deformation mode.
Results predicted by the present model showed the non-linear trend of the contact conductance vs.the relative pressure as Garnier-Begej experimental data did. Also, the predicted results were in good agreement with Rapier-Jones-McIntosh and Bain's experimental data.