One aspect of nuclear reactor safety assessment is a prediction of fuel behavior associated with postulated overheating events, which includes an assessment of the role of fission product inventory, contained within irradiated fuel elements, on fuel relocation potential. In general, the gaseous fission products, such as xenon and krypton, have been considered the most likely candidates for fuel relocation. However, the fissioning of UO2 fuel in both a fast and slow neutron spectrum also results in the generation of a significant quantity of such metallic fission products as barium, palladium, molybdenum, and other metal species. Metallurgical analysis of irradiated fuel indicates that such metals aggregate into inclusions found throughout the fuel matrix. During normal reactor operation, such metallic inclusions are in a solid state, but at the elevated temperatures expected for overheating accident transients, such inclusions may tend to volatilize, contributing to fuel motion. This paper involves an assessment of effect of such metallic fission product inclusions on fuel motion potential for accident analysis and is the first known attempt at such an assessment. To assess this potential, two limiting calculational assessments were made. Results indicate that if the inclusion constituents are assumed to be segregated elementally, then the presence of the highly volatile species such as antimony, palladium, and iron can result in an estimated 30% expansion just prior to fuel vaporization. However, under the more probable assumption of complete miscibility of constituents, the effect of metallic inclusion vaporization would be of little consequence to fuel motion.