Vaporization Behavior of Cs in Plasma Melting of Simulated Low Level Miscellaneous Solid Wastes

Abstract

A DC transfer type plasma with a maximum output of 60 kW was used to melt 10 kg of carbon steel and 3 kg of granular oxide mixtures ( Fe2O3, Al2O3, SiO2 and CaO) containing non-radioactive cesium nitrate, for measuring Cs vaporization. These materials are the main components of low level miscellaneous solid wastes. The vaporization rate constant values obtained by approximating Cs vaporization by a first order reaction rate formula were in the range of (4.01–7.1)×10-6 (m/s). The vaporization rate constant of Cs did not depend on the initial Cs content, and increased with the increase of slag basicity ( %CaO/%SiO2). Since the vaporization rate constant was unaffected by the viscosity of the slag on which the Cs transfer rate in the slag depends, the Cs vaporization phenomenon from the slag can be estimated to be controlled by the vaporization step from the slag surface.