One-dimensional transient analysis of the dual-fluid reactor system

The dual-fluid reactor (DFR) has been introduced into the nuclear community as a completely new concept for molten salt fast reactors (MSFRs). It has provided possibilities of having a reactor with inherent safety features, high fuel utility, fuel breeding, high efficiency, compact structures, online refueling, actinides burning, and minimum waste. DFR uses molten uranium–plutonium trichloride (UCl₃ + PuCl₃ [UPu]) as the default fuel salt and transuranium (TRU) fuel salt as the optional fuel salt. These reactors adopt liquid lead as the coolant in the reactor core. The fuel salt goes into a pyro-processing unit (PPU) for fuel re-freshening, and the liquid lead goes into a heat exchanger where it is cooled by a secondary gas coolant, which could be helium or super-critical carbon dioxide (sCO₂). In this study, the system dynamics and transients of a DFR with 3000 MW (DFR3G) and 250 MW (DFR250M) are investigated. For this purpose, a model with three one-dimensional nodalized loops coupled with point-kinetic neutron dynamics is constructed based on the heat balance equations to investigate the system responses to the changes of various boundary conditions. The calculation provides a preview of the transient behavior of the DFR system, and the analysis is provided from a reactor safety point of view. The conclusion discusses the research and development status of the DFR for future improvements.