Analysis of Freeze Plug Melting and Fuel Salt Relocation in Molten Salt Fast Reactor using the Semi-Implicit Moving Particle (MPS) Method: A Validated Approach for Passive Safety Mechanism Study
Yulia Mifftah Huljanah (a), Asril Pramutadi Andi Mustari (b*), Abdul Waris (b), Anni Nuril Hidayati (a)

a) Physics Department, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, 40132, Indonesia
*pramutadi[at]fi.itb.ac.id
b) Nuclear Physics and Biophysics Research Division, Physics Department, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, 40132, Indonesia

Abstract

The Molten Salt Fast Reactor (MSFR), a prominent Generation IV reactor design, offers improved safety by eliminating graphite as a moderator and incorporating a passive safety system. This system employs a draining mechanism to transfer fuel salt to a safety tank via gravity during reactor accidents when the core temperature rises, causing the freeze plug to melt and enabling fuel salt relocation through the drainage pipe. Understanding the fuel salt relocation mechanism is crucial in ensuring the reactor^s safety and performance. In this study, we present a particle-based approach using the Semi-Implicit Moving Particle (MPS) method, which accurately represents fluid as particles carrying essential physical properties. We validate the MPS method as an alternative tool for investigating fuel salt relocation in the MSFR, comparing its results with the well-established Delta-SPH method for verification. The simulations encompass scenarios with and without obstacles, involving water-PEO fluids known for their distinct densities and propensity to induce splashing phenomena. The excellent alignment of MPS method results with Delta-SPH method outcomes confirms its effectiveness in predicting freeze plug melting and fuel salt relocation in the MSFR, providing valuable insights into the passive safety mechanisms. This research contributes to enhancing the safety and efficiency of advanced molten salt reactor designs.

Keywords: Molten Salt Fast Reactor (MSFR), freeze plug melting, fuel salt relocation, passive safety, Semi-Implicit Moving Particle (MPS) method, Delta-SPH method, particle-based simulation.

Topic: Nuclear Science and Engineering