In order to determine whether the EVOLVE fusion blanket design is viable, thermal-hydraulic analyses were performed on the outboard liquid lithium blanket trays. Various methodologies were employed to determine the vapor fraction distribution within these liquid metal trays. Detailed analysis of the vapor fraction is required for understanding of neutron streaming and for heat removal issues involving the liquid lithium trays. The effect of the magnetic field on the liquid lithium pool is still not fully understood and can strongly influence the potential mode of heat removal. Vapor fractions may be greater than 50% for negligible magnetic coupling between the system and the liquid lithium pool. If the magnetic field is coupled to the liquid lithium pool smaller vapor fractions are predicted, ranging up to 12%. Experiments are proposed to determine the magnitude of this coupling and ultimately the vapor fraction distribution of the liquid lithium pool.