A Pelletizing Model and Its Application to Radioactive Waste Treatment

Abstract

A pelletizing mechanism was studied theoretically and experimentally to transform radioactive waste powders into dense and hard pellets in conjunction with the development of a new volume reduction system, a drying and pelletizing system. A pelletizing model was proposed based on plastic deformation of powder particles. Its validity was confirmed by fundamental experiments. From the model, such pellet properties as density and strength can be predicted over a wide compacting pressure range of a pelletizer using one material constant, the shear modulus of the powder, and one experimental value. This led to the proposal of a method to control the pelletizer and to estimate pellet properties. Usefulness of the method was confirmed experimentally from pilot plant tests.