The choice of molten lead as a chemically inert and low-pressure coolant for a nuclear reactor can provide enhanced safety features. However, research is still needed in areas such as materials performance and corrosion control. In this paper, we investigate the erosion/corrosion of aluminized and non-aluminized Type 316H stainless steel (316H) and non-aluminized 316L stainless steel (316L) under high-velocity lead flow using the newly commissioned BULLET (Bangor University Lead Loop Erosion/corrosion Test) facility. In this loop, lead flow at a rate of 3.3 m/s was applied across the sample surface for a period of 500 h at 420°C and an oxygen content of 10−8 wt%. Posttest materials characterization of the samples using scanning electron microscopy–energy dispersive X-ray spectroscopy and stylus profilometry is presented. A reduction in surface roughness was observed in 316L, as well as pitting corrosion. With the same exposure conditions, 316H was found to differ in erosion/corrosion behavior from 316L.