SIMULATION OF MODIFIED FREEZE VALVE MELTING AND FUEL EVACUATION IN MOLTEN SALT FAST REACTOR USING MOVING PARTICLE SEMI-IMPLICIT (MPS) METHOD

• Main Author: Fatiya Nabiilah, Banafsaj
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67994
• Institution: Institut Teknologi Bandung

The Molten Salt Fast Reactor (MSFR) is one of six types of reactor designs selected as generation IV reactors. One of the important aspects in the selection of generation IV reactor design candidates is the high safety system. MSFR has a unique passive safety system, which is a drainage system that functions to evacuate fuel salt into the safety tank by utilizing fuel salt heat and gravitational force. The drainage system consists of a freeze valve, drainage pipes, and a safety tank. When an accident occurs, the core temperature will increase and melt the freeze plug, then the fuel salt will move towards the safety tank through the drainage pipe. Evacuation time is very important for the MSFR safety system to ensure the subcritical condition of the reactor before it gets to the safety tank. In this study, the Moving Particle semi-implicit (MPS) method was used to simulate the melting of a freeze valve and the evacuation of fuel salt to safety tanks. This method can be used to examine how particles move within an uncompressed medium. The idea behind this approach is to eliminate the grid by converting the differential operators in the governing equation into equivalent particle interactions. Simulation of freeze valve melting is carried out using 2 types of freeze valve, i.e multiple plugs and modified multiple plugs. Variations of alloys were carried out in each type of freeze valve using Hastelloy-N, Heynes-242, and ODS Alloy (MA754). The three alloys have different thermal conductivity values. The alloy with the maximum thermal conductivity used in the freeze valve result requires less time to reach the melting point. In the second simulation, which simulated the transfer of fuel salt to the safety tank, various liquids with various physical characteristics were used. These fluids were chosen to show descending mechanism of different parametric fluids. Based on the simulation results, it can be concluded that the fluid's physical characteristics, such as density and viscosity, would influence the flow rate, pressure, and splash pattern when it collides with a plane.