Fluid/Structure Interaction and TUF Code Modelling

Abstract

In the course of analysis of Steam Generator (SG) divider plate integrity under Loss-Of-Coolant-Accident (LOCA) conditions, it became clear that the pressure differential across the divider plate is strongly affected by the ensuing movement of the divider plate. The effect of the divider plate movement on the thermalhydraulics has been studied in detail at Ontario Hydro. In this paper, emphasis is placed on the fundamental physics involved in the phenomena. Two physical problems, which can be solved analytically, are presented in this paper, which may be used for code validation: 1) The first one relates to the fundamental physics of pressure wave propagation generated by the motion of a piston in a pipe, 2) The second one deals with a lumped volume (or node in simulation codes) with inlet and outlet pipes, which is representative of the bowl of a SG with the tubes and the nozzle as inlet and outlet. Fluid/structure interaction modeling for SG divider plate integrity study has been implemented in the TUF code at Ontario Hydro. The structure-to-fluid part of the coding is tested against these two physical problems. The results have demonstrated the code capability for simulations of fluid/structure interaction problems.