Application of Electrical Fields in the Study of Concretes with respect to theTransport of Several Ionic Species Present in Radioactive Wastes: Characterisationand Decontamination

摘要

Cement based matrices are being increasingly used to confine toxic and radioactive wastes; therefore, determination of therndiffusion coefficients of ionic contaminants becomes of strategic importance in order to characterise the system in relation tornthe release of ionic components of wastes. In this paper, a summary of the determination of steady-state diffusion coefficientsrnof Cs~+, Sr~(++), Co~(++) and Fe~(+++) through concrete, as well as the extraction of these ions from cementitious matrixes, by anrnaccelerated procedure based in the application of electrical fields (migration experiments), is presented. As a result, thernapplication of electrical fields to contaminated structures arises as a new technique to extract radioactive ionic species fromrnconcrete, which allows the management of initially radioactive wastes as conventional ones, after declassification. This method ofrndecontamination has been patented by ENRESA (Spanish Company for the Management of Radioactive Wastes) in associationrnwith the IETcc.