Comparison of Boron Carbide, Gadolinium Oxide, and Hafnium as Qualified Molten Salt Reactor’s Control Rods Material

Abstract

Abstract The development and research of the Molten Salt Reactor (MSR) has recently seize the attention. Lots of MSR designs have been modeled based on its materials, neutronic behaviour, thermal-hydraulic behaviour, and particularly its safety systems. A reactor’s core has been modeled based on the design of ThorCon Reactor using Monte Carlo N-Particle 6 computational code with BeF2-NaF-UF4-ThF4 mixture as the fuelsalt. The core contains 84 hexagonal fuel logs and a hexagonal control rod log. This research compared three different materials of control rods, i.e. B4C, Gd2O3 and Hf. The comparison between those materials are seen according to reactor’s criticality. The keff at fully withdrawn position is 1.01887 that indicates a critical condition. When the control rods are fully entered the keff are (0.98293 ± 0.00012); (0.97386 ± 0.00011); (0.99203 ± 0.00012) for control rods’ materials in sequence B4C, Gd2O3 and Hf. The decretion of the criticality shows the materials’ ability to absorb the neutron. The lower the criticality, the better material’s absorption ability.