For 2,300 hours, the molten salt pump Shaft Seal Test Facility (SSTF) operated at the University of Michigan’s Thermal Hydraulics Laboratory, according to an article from UM. The large-scale experiment was designed to evaluate shaft seal performance in high-temperature pump systems. Fewer than 10 facilities worldwide have successfully operated fluoride or chloride salts for more than 100 hours using over 10 kilograms of material.