Abstract: A valve for controlling the flow of solids comprises a vessel having an overflow point, an inlet line for discharging solids into the vessel positioned within the vessel such that the inlet line's discharge point is lower than the vessel's overflow point, and apparatus for introducing a fluidizing fluid into the vessel. The fluidizing fluid fluidizes the solids within the vessel so that they overflow at the vessel's overflow point. For the removal of nuclear waste product the vessel may be placed within a sealed container having a bottom connected transport line for transporting the solids to storage or other sites. The rate of solids flow is controlled by the flow rate of the fluidizing fluid and by V-notch weirs of different sizes spaced about the top of the vessel.