Spent nuclear fuels and fuel debris stored underwater must eventually be prepared for dry storage (e.g., repository disposition). This preparation involves some degree of fuel drying. Primary considerations for a fuel drying process are the containment configuration of the spent fuel material and the type of fuel material (e.g., oxide, metal, hydride, alloy, carbide, epoxied, debris). The Idaho National Engineering and Environmental Laboratory has built and operated three heated vacuum drying systems and placed into interim dry storage all of these fuel types. The drying systems and process have been tested and modeled so that the extent of dryness can be predicted and used to plan and perform drying operations. This paper presents this drying method.