The effect of Copper utilization on MSFR's safety plug performance simulation by using MPS

Abstract

Generation IV reactors are developed and expected to have a higher safety level than the previous reactors. One of the generation IV reactors is Molten Salt Fast Reactor (MSFR) with the freeze plug and drainage pipe as the integrated safety system. When an accident occurs, the fuel flows down, directly interacts and melts the freeze plug. Moreover, the fuel will be cooled at the safety tank. This research aims to simulate the freeze plug melting process by using Moving Particle Semi Implicit (MPS) method. MPS is a particle method based on Lagrangian mechanism developed by Koshizuka and Oka in 1996. Mainly, the freeze plug consisted of frozen salt and Hastelloy N. There were two kinds of freeze plug geometry used in the simulation, which were without and with copper. The copper thickness was varied between 1.5 - 3.0 mm with 0.5 mm intervals. The additional copper thickness was performed toward the inside of the freeze plug. The height and the radius of freeze plug were 30 mm. The thickness of Hastelloy N and the copper were 8.5 mm and 2.5 mm, respectively. S-curve temperature distribution was initially applied due to the heat transfer between molten salt and the freeze plug material. The results show the melting time of with and without copper cases were 125 s and 250 s, respectively. Moreover, the thicker copper led to the faster freeze plug melting process.