METHOD FOR TREATING METALLIC WASTE CONTAMINATED BY RADIONUCLIDES

摘要

The present invention relates to methods for treating metallic waste contaminated by radionuclides, wherein one of said methods comprises deactivating the metallic waste in a liquid medium using an etching solution, a cleaning solution and water. The metallic waste is then melted in an induction furnace while adding refining fluxing agents thereto. The ingots are further submitted to a dosimetric control before solidifying the etching solution. The deactivation of the metallic waste in a liquid medium is first carried out using the etching solution that contains from 5 to 200 g/l of a strong acid and from 0.1 to 15 g/l of a sulphur-containing activator or corrosion inhibitor at a temperature of between 10 and 100 DEG C. The method further comprises applying the cleaning solution that contains from 2 to 100 g/l of a strong acid and from 1 to 20 g/l of an oxidant at a temperature of between 10 and 90 DEG C before carrying out the treatment using water. The metal ion concentration in the etching solution is monitored so that in case said concentration exceeds a predetermined value, a portion of said solution is removed for solidification while the corresponding portion of the remaining solution is strengthened using a strong acid. During the melting process, the content of refining fluxing agents relative to the metal is kept in a range of between 0.9 to 4 wt.%.