Screw compactor/dry active waste volume reduction and solidification technology

Because of the large amounts of dry active waste (DAW) generated, treatment requires many man-hours and expensive equipment, resulting in the economical burden of waste management at nuclear power plants. To solve this problem, a new technology, called the screw compactor, has been developed. DAW generated at nuclear power plants contains such thermoplastics as polyethylene, which is utilized as a binder. The polyethylene is melted by compression and friction heat, mixed with other materials, and then extruded from the screw compactor. The screw compactor consists of one axial screw housed in a shell structure that incorporates a DAW shredder, hopper, and cutter. Shredded DAW is received in the hopper, then fed into the compactor. Wastes containing polyethylene are melted, mixed with other materials, and pressed by compression and friction heat. The screw compactor then extrudes these wastes from the nozzle. The cutter shears the extrusion into pellets, which are poured into drums. The screw compactor's design also permits higher packaging efficiency by the easy attachment of a piston-type machine that forms the pellets into pillar-shaped products. Most DAW, compactible as well as non-compactible wastes, can be volume reduced and compacted.