Development of three-dimensional thermal-hydraulics analysis code TSG for straight tube steam generators; Validation with the test data and applicability confirmation at heat transfer tube plugging conditions

Yoshikawa, Ryuji ; Imai, Yasutomo*; Tanaka, Masaaki 

TSG (Three-dimensional Thermal-hydraulics Analysis Code for Steam Generators) has been developed for the numerical simulation of thermal hydraulics in double wall straight tube steam generator (SG) of Sodium-cooled Fast Reactor (SFR) by the Japan Atomic Energy Agency (JAEA). TSG is a thermal hydraulics simulation system for double wall straight tube SG which couples the sodium side three-dimensional simulation with water side multi-channel simulation. The three-dimensional flow field in sodium side is simulated by the CFD code FLUENT with porous media model. The multi-channel two-phase flow in water side is simulated by in-house code with drift-flux model. The sodium side simulation is coupled with water side simulation by the transmission of heat transfer rate through the heat transfer tube, therefore the overall thermal hydraulics in SG can be evaluated transiently. This report presents the sodium-water coupled simulation models of TSG, and the simulation results of fundamental validation of TSG with the steady state results of 1MWt SG tests. Next, the evaluation results of temperature deviation at the heat transfer tube plugging conditions in a straight tube SG of a commercial reactor, and the evaluation results of three-dimensional temperature distribution and structural integrity at the heat transfer tube plugging condition for the large-sized SG including the inlet and outlet plenums are described. In addition, the applicability of TSG to the flow stability analyses for 1MWt SG instability tests is presented in the appendix.