Abstract
In order to predict the water-vapor two-phase flow behavior in a fuel bundle of an advanced light-water reactor, large-scale numerical simulations were carried out using a newly developed two-phase flow analysis method. Conventional analysis methods such as subchannel codes need composition equations based on many experimental data. Therefore, it is difficult to obtain highly prediction accuracy on the thermal design of the advanced light-water reactor core if the experimental data are insufficient. Then, a new two-phase flow analysis method using a modified interface tracking method was proposed. The coalescence and fragmentation of small bubbles were analyzed numerically and the bubbly flow dynamics in narrow fuel channels were clarified. Moreover, the liquid film flow in a tight-lattice fuel bundle which is used to the advanced light-water reactor core was analyzed and the three-dimensional water and vapor distributions around fuel rods with spacers were estimated quantitatively.
