| dc.description.abstract | Molten Salt Reactors (MSR) are emerging as one of the fastest developing advanced reactor designs in United States. Flexibility in MSR fuels offers unique opportunities in both performance and applications, as well as unique challenges. This thesis offers an evaluation of fuel salt mixtures in a range of MSR configurations. To make these studies possible, modeling approaches were developed to synthesize fuel salt compositions and integrate them into reactor physics models.
A group of molten salt fuel candidates were identified, cataloged, tested, and evaluated. This work is in response to the growing interest in molten salt reactor technology. The process of selecting molten salt fuel candidates begins with a review of the existing thermophysical properties of known molten salts. This review revealed the unavailability of data for many molten salts and the necessity of a centralized database of the properties available for molten salts. Next, the identified molten salts are screened to determine which molten salts satisfy the objective functions necessary for viable MSRs. Some desirable characteristics of molten salt fuels include low melting point, high boiling point, low vapor pressure, low viscosity, good thermal conductivity, high heat capacity, chemical inertness, good optical transparency, high radiation stability, and high solubility of fuel elements (uranium and plutonium) and fission products in the salt. The salts that were chosen as a potential MSR fuel were put into a python script that created Serpent models based on reference reactors created for both the thermal and fast neutron spectrum. The script creates a critical system based on an inputted molten salt system and runs a depletion calculation. After which, the performance of each molten salt was evaluated. This analysis confirmed that the best MSR fuels for the thermal spectrum are fluoride salts, whereas the best MSR fuels for the fast spectrum are chloride salts. In terms of lifetime, the best performing molten salts were LiF-BeF₂-UF₄ in the thermal reactor and MgCl₂-UCl₄ in the fast reactor. This work shows that MSRs have the capacity to be a source of excellent resource sustainability and desirable safety characteristics. However, the MSR is an undeveloped reactor with few component technologies developed for commercial operations -especially in the fast neutron region. | |
