The filling dynamics and phase change performances of molten salt in cold receiver pipe during initial pumping process are numerically analyzed with variable inlet velocity due to pump characteristic curve. In general, cold receiver pipe during initial pumping process will be frozen for molten salt solidification as the inlet temperature is lower than critical temperature, or else it will be unobstructed with melting process at higher inlet temperature. During pumping process with melting, the flow velocity will first decrease by solidification and then increase by melting effect, and the melting time decreases with inlet temperature. As the freezing phenomena appears during pumping process, the flow velocity will decrease to zero, while the pressure loss reaches the maximum pressure head, and the freezing time increases with inlet temperature. Since a solid layer exists adjacent to the pipe wall in phase change region, the flow velocity and pressure loss remarkably increases along flow direction, and the phase change region will dominate the pressure loss. As the inlet temperature decreases, the phase change region remarkably enlarges, and the filling time rises. (C) 2013 Elsevier Ltd. All rights reserved.