Abstract: An easily-movable plug seal that is susceptible to quick and ready longitudinal adjustment in the central, lengthwise bore of an internally differentially heated (or cooled) extruder screw for sequentially diverse and distinct heat controlled zones within the extruder barrel is comprised of at least a single, cup-like member that is adequately flexible and supple to be flared laterally outwardly and urged into tight wall contact to make a sealing engagement against the internal screw bore wall upon pressurization of the interior of the plug seal member by the heat transfer fluid being passed into and applied within the screw.

Abstract: In a process for the admixture of radio-active waste with an encapsulating resin in a container which will accompany the waste to a disposal site, the improvement which comprises providing a generally annular deflectable foil at an upper open end of the container to minimize contamination by splashing.