Estimation method of Cs capturing ratio during plasma-melting treatment of low-level radioactive miscellaneous solid wastes

To establish a method for estimating the capturing ratio of Cs to the solidified products in a plasma melting process for the treatment of low-level radioactive miscellaneous solid wastes, the migration behavior of Cs during melting have been investigated by conducting the melting tests of simulated waste materials with cold tracers. The temporal change of concentration of Cs in the molten slag was expressed by a first-order type reaction rate formula when the samples were melted completely. And also, using the apparent rate constant and the temporal change of the molten bath form estimated the temporal change of concentration of Cs in the molten slag before the waste materials were melted completely. From these results, we proposed the method for estimating the capturing ratio of Cs from only three parameters: the malting rate of the waste materials, the apparent vaporization rate constant of Cs and the surface area of the molten bath. The apparent vaporization rate constant depends strongly on the slag basicity and can be estimated from the waste composition, therefore, the Cs capturing ratio can be estimated simply by the treatment conditions in a plasma melting process before melting. (author)