Design of a He-Xe Gas-Cooled Nuclear Microreactor System Based on Detailed Models of the Cycle Components

Abstract Nuclear microreactor has disruptive potential as an alternative to carbon-intensive energy technologies based on its mobility, resilience, independence from the grid, long refueling intervals, and low-carbon emissions. A He-Xe gas-cooled nuclear microreactor with the dry-cooled Closed Brayton cycle is designed in this study based on detailed models of the cycle components. Design methods of different components are included. A one-dimensional single-channel model is developed for the reactor core. A one-dimensional discretization is also used for the recuperator, while the two-dimensional temperature field is adopted for the design of the precooler. The turbomachinery uses the mean-line design method. Three He-Xe mixtures are investigated, namely 4 g/mol (pure helium), 15 g/mol, and 40 g/mol. It is found that the system volume is mainly occupied by the reactor core and precooler, and the volume of the turbo-machines is rather small. The 40 g/mol He-Xe achieves the highest thermal efficiency of 42.09% due to the efficiency improvement of the turbo-machines, and the turbomachinery reduces from 5 stages of pure helium to a single-stage of 40 g/mol He-Xe.