PLASMA SURFACE DECONTAMINATION: METHOD AND APPARATUS FOR REDUCING RADIOACTIVE NUCLEAR WASTE AND TOXIC WASTE VOLUME

摘要

Plasma reactors and methods are provided for reducing the volume of radioactive nuclear wastes or toxic wastes where the surface contamination is the main source of radioactivity or toxicity. The radioactive or toxic wastes are prepared in the form of small particles and fed into a pulsed plasma reactor operating in fluidized bed configuration. The repetitively pulsed radio-frequency (rf) powered plasma reactor generates high power plasma for pulse duration between 10 μ-10 ms. During the pulse, the plasma deliver a short burst of intense heat flux to the surface of waste feed particles. Due to the short pulse duration, the heat flux is concentrated on the surface without propagating much to the core of the particles. The localized heat flux preferentially removes the surface contaminants via vaporization. The removed waste in the vapor phase will be transferred out of the reactor where it may undergo additional treatments or disposed accordingly in a reduced volume. The residual particles which are free from surface contaminants can then be recycled or disposed as non-toxic or non-radioactive waste. By controlling the treatment time inside the plasma reactor along with the pulse power, duration and repetition rate, and the plasma chemical composition, the thickness of removed surface layers can be controlled to provide the efficient surface decontamination.