Abstract: A vertical helical conveyor for conveying radioactive materials submerged in water to a discharge point above the surface of the water. The conveyor is partially immersed in the water and consists of a helical fin fixed between an inner vertical shaft and an outer vertical tube. Helical vibratory motion is applied to the inner shaft to convey the waste material upwardly through the water to a discharge port above the surface of the water. A ferrule extends the lower end of the tube beyond the lower end of the shaft to define a space below the lower end of the helical fin. A compressed air pipe is located inside the shaft and extends from a point above the surface of the water to a point just below the closed end of the shaft into the space defined by the ferrule. Supplied to the upper end of the air pipe is compressed air of just sufficient pressure to form and maintain in the space an air cushion in the form of a bubble.