Determine uranium-mononitride surface diffusivity

Determine the surface diffusivity of uranium mononitride through direct measurements or atomistic calculations so that the pore mobility and pore-drag contribution to uranium-mononitride grain-boundary mobility can be quantified without relying on uranium-dioxide estimates.

Background

The pore-drag model requires the pore mobility, which depends on the surface diffusivity of uranium mononitride. Because the study does not have material-specific data, it adopts an Arrhenius estimate derived from uranium-dioxide measurements. The resulting uncertainty propagates into the inferred intrinsic grain-boundary mobility and limits the precision of the reported parameters.

Resolving the surface diffusivity of uranium mononitride would allow the pore-mobility model to be evaluated using material-specific input and would improve the determination of whether pore drag is negligible under the experimental conditions considered.