This publication documents the results of experimental investigations and computational fluid dynamics studies on thermohydraulics, specifically models and correlations on pressure drop and heat transfer involving to liquid metal and molten salt coolants under different operating conditions, including the feedback on neutronics effects. It presents new data, or verifies existing data on, thermo-physical properties of liquid metal and molten salt coolants, and describes tools for on-line monitoring and control of coolant chemistry. Methods to improve the corrosion resistance between heavy liquid metal coolant and components, structure material and instrumentation are also examined.