Neutron physical feasibility of small modular design of dual fluid reactor

The Dual Fluid Reactor (DFR) is a fast reactor concept proposed by the Institute of Solid-state- and Nuclear physics (IFK) in Berlin. The design of DFR aims to combine the Gen-IV Molten Salt Reactor (MSR) and the Liquid-Metal Cooled Reactor (SFR, LFR), which means that the molten-salt fuel is no more used as coolant while the heat is removed in a separate loop by liquid lead, to improve these two concepts. Without control rods, DFR is given hope to react and take steps to the change of operation conditions automatically by its inertial negative temperature feedback. Since fuel and coolant are both liquid, the circulation speed of each liquid is considered capable to adjust operational parameters for DFR. The original design of a 3000MWth (Wang, 2017) and a downscaled version of 500MWth (He, 2016) were analyzed in the aspects of reactor physics and thermal-hydraulics. For the practical purpose, this paper has proposed a small modular version of the DFR, which has power output of 2MWth. The reactor with such power level is expected in various applications. Therefore, it is necessary to perform the more explicit analysis on the design than the previous ones. The analysis focuses on the neutronic calculations with the default fuel salt of U-Pu mixture under steady state conditions.