THE IMPACT OF SILICON CARBIDE COATING ON THE REACTOR PHYSICS OF SINGLE FLUID DOUBLE ZONE-THORIUM MOLTEN SALT REACTOR

Abstract

Graphite-moderated molten salt reactor (MSR) is subject to a highly corrosive nature of molten salt coolant. Apart from that, molten salt can intrude the pores in the graphite moderator, creating hotspot and complicating post-irradiation waste management. A thin layer of sacrificial coating can be applied in the inner side of MSR fuel channel to reduce salt intrusion into the graphite and prevent corrosion on the graphite surface. One of the potential coating materials is Silicon Carbide (SiC). The impact of SiC coating on the graphite surface to reactor physics parameter of an MSR, however, has not been analyzed. This study attempts to analyse this issue, using Single Fluid Double Zone-Thorium Molten Salt Reactor (SD-TMSR) as the MSR model. Reactor physics parameters of SD-TMSR using various SiC coating thicknesses, ranging from 0.2-1 mm, were calculated using MCNP6.2 radiation transport code and ENDF/B-VII.0 cross-section library. From the calculations, SiC does not severely impact the temperature coefficient of reactivity (TCR) and kinetic parameters, although no apparent pattern was shown in TCR value against SiC coating thickness. The breeding ratio (BR) was slightly reduced, and doubling time (DT) was lengthened with the increase of SiC coating, with the DT was compromized the most. From these findings, a SiC coating of 0.2 mm can be applied without notably reducing the reactor physics performance of SD-TMSR.