Numerical Analysis of Nonstationary Thermal Response Characteristics for a Fluid-Structure Interaction System

Abstract

Nonstationary thermal response analysis for a fundamental sodium experiment simulating thermal striping phenomena was carried out using a quasi-direct numerical thermohydraulics simulation code with a third-order upwind scheme for convection terms and a boundary element method code for thermal response evaluation of structures due to random sodium temperature fluctuations developed at Power Reactor and Nuclear Fuel Development Corporation (PNC). Discussions centered on an applicability of the numerical method for the damping effects of the temperature fluctuations in the course of heat transfer to the inside of structures from the fully turbulent region of sodium flows through the comparisons with the experiment. From these comparisons, it was confirmed that the numerical method has a sufficiently high potential in accuracy to predict the damping effects of the temperature fluctuations related to the thermal striping phenomena. Consequently, it is concluded that the numerical prediction by the method developed in this study can replace conventional experimental approaches using 1:1 or other scale model aiming at the simulation of the thermal striping phenomena in actual liquid metal fast breeder reactor (LMFBR) plants. Furthermore, economical improvements in the FBR plants can be carried out based on the discussions of optimization and rationalization of the structural design using the numerical methods.