Development of a New Thermal HF Plasma Reactor for the Destruction of Radioactive Organic Halogen Liquid Wastes

A newly patented process employing thermal plasma for destruction of radioactive organic halogen liquid wastes is proposed. This studied safe system can destroy a great variety of wastes, even mixed together, using plasma torch as high temperature source. At the exit of the process, only non-toxic products are formed as atmospheric gases, liquid water and halogen sodium salt. The process has been built with the help of thermodynamic and kinetic simulations. A good atomic stoichiometry is necessary for avoiding the formation of solid carbon (soot) or toxic COCl{sub 2}. That why liquid water is added to the waste in the plasma flow. Then, an introduction of air cools and dilutes the formed gases and adds oxidant agent achieving oxidation of explosive H{sub 2} and toxic CO. Due to the high concentration of hydrochloric acid, an efficient wet treatment using soda traps it. Subsequently, the exhaust gases are only composed of Ar, O{sub 2}, N{sub 2}, CO{sub 2} and H{sub 2}O. In the first experimental step, pure organic molecules, mixed or not, without halogen have been destroyed. The experimental results show that all the compounds have been completely destroyed and only CO{sub 2} and H{sub 2}O have been formed without formationmore » of any toxic compound or soot. After these encouraging results, chlorinated compounds as dichloromethane or chloroform have been destroyed by the process. In this case, the results are close to the previous one with an important formation of hydrochloric acid, as expected, which was well trapped by the soda to respect the French norm of rejection. A specific parameter study has been done with dichloromethane for optimising the operating condition to experimentally observe the influence of different parameters of the process as the stoichiometry ratio between waste and water, the air addition flow, the waste flow. The final aim of this study is to develop a clean process for treatment of radioactive organic halogen compounds. A small scale reactor is being studied to prove the capability of the process for radioactive organic halogen liquid waste. (authors)« less