Verification of a fluid-structure-interaction model for seismic analysis of Gen IV nuclear power plants

Generation IV liquid-metal nuclear reactors utilize sodium or lead-bismuth as the coolant, which enables thermal efficiencies not possible with the traditional pressurized water and boiling water reactors that make up the commercial nuclear fleet in the United States at this time. Thermal efficiency is achieved by minimizing the thicknesses of materials used in the construction of the reactor vessel and its internals, which may compromise seismic robustness. Design and seismic qualification of liquid metal reactor vessels and their internals will rely heavily on fluid-structure-interaction analysis, for which verified and validated computer models will be needed. This paper presents preliminary results of a numerical study that has multiple goals, including: 1) verification of a numerical model for the seismic analysis of a ground-supported cylindrical tank using the Arbitrary-Lagrangian-Eulerian (ALE) formulation in LS-DYNA, and 2) analysis of an ALE numerical model of a generic liquid-metal reactor vessel to guide the design of a test article to be tested in late 2018 on an earthquake simulator at the University at Buffalo. ALE models were used to enable calculations for a wide range of seismic inputs for which nonlinear fluid response is possible. Results of analysis of the ground-supported tank for low amplitude earthquake shaking, for which analytical models exist, verified in part the ALE model. Analysis of an ALE model of the reactor vessel has guided the design of the test article planned for earthquake simulator testing, including maximum intensity of shaking, vessel wall thickness, and instrumentation.