This study focused on designing a cost-effective heat exchanger for a 20-MW FLiNaK-SCO2 Secondary Heat Exchanger in Fluoride salt-cooled High-temperature Reactors. Specific Printed Circuit Heat Exchanger geometries were investigated for those cases where Fanning factor and Nusselt number correlations were available. Straight, S-shape, Offset Strip Fin, and zigzag 52 channels were considered for the SCO2 side while straight, zigzag 15, rectangle OSF 7.565 mm, and rectangle OSF 2.40 mm channels were considered for the FLiNaK side. Thermal-hydraulics, mechanical aspects, and corrosion rate were taken into account. A cost analysis was performed to combine the effects of heat transfer performance and pressure drop in heat exchangers. Single banking and double banking were also considered. Finally, the best PCHE channel configurations on SCO2 and FLiNaK sides were proposed. (C) 2016 Elsevier Ltd. All rights reserved.