Large-Scale Simulations of Two-Phase Flow Dynamics in Fuel Channels of Nuclear Reactor Cores

摘要

Development of an advanced water reactor has been performed by Japan Atomic Energy Research Institute. In this reactor a tight-lattice core is applied and the gap spacing between each fuel rod is designed to be around 1 mm. Coolant flows upward into narrow fuel channels inside the reactor core. Here, it is disturbed by spacers that are set to arbitrary axial positions. As a result, a complicated two-phase flow is formed around each fuel rod. By present large-scale numerical simulations, the three-dimensional water-vapor two-phase flow distribution in the narrow fuel channels was first clarified quantitatively