It is necessary to accurately determine the critical heat flux (CHF) of cooling systems used infusion reactors. Currently, sufficiently accurate CHF correlations for one-sided heating have not been established. A design method for subcooled boiling cooling systems using swirl tubes is described. From a review of existing work under uniform heating conditions, the correlations of Gunther and Nariai-Inasaka are recommended for smooth and swirl flow, respectively. The effects of thermal conductivity and geometry of the cooling sections on both the nonuniformity factor and the peaking factor were investigated by solving a heat conduction equation. For swirl flow under one-sided heating, the CHF multiplier increases with the increasing nonuniformity factor. Design criteria for subcooled boiling swirl-tube cooling systems are presented.