Abstract: Technetium-contaminated nickel is decontaminated by electrolytically dissolving nickel having a gross beta activity of at least about 74 Bq in a sulfuric acid solution having a pH between about 0.5 and 2.0. The applied voltage is from 2.0 v/cell to 5.0 v/cell for dissolving the nickel and contaminants while cathodically producing hydrogen gas. Technetium (+4) species in the acid solution is oxidized to the technetium (+7) species. The pH of the technetium-containing acid solution is adjusted to between 2.5 to 4.5. Particulates in the acid solution are filtered from the solution for reducing the gross beta activity of the acid solution to less than about 50 Bq/gm. Radioactive ions (including technetium complexes) are sorbed in an anionic exchanger and a cationic exchanger for reducing the gross beta activity of the acid solution to less than about 20 Bq/gm. After verifying the gross beta activity of the acid solution, the acid solution is either recycled or charged to a electrowinning step.

Abstract: As shown in FIGS. 8 and 9, the instant invention provides a concave filter 530 which comprises two oppositely disposed geotextile fabric sheets 560A and 560B. Fabric sheets 560A and 560B are porous for filtering the liquid from the slurry solids and may be fabricated from a geotextile material such as the material composing filter sheets 330a and 330b (see FIG. 4). Disposed between fabric sheets 560A and 560B is at least one drainage grid 350 such as the drainage grid 350 illustrated in FIGS. 4 and 4A.

Abstract: Nickel (or other transition metal) contaminated with about 5 ppm technetium is decontaminated by dissolving the nickel and the technetium into an aqueous acid solution while introducing a graphite or activated carbon powder into the acid to immediately adsorb the dissolving technetium. The technetium-contaminated powder is separated from the aqueous acid solution and the nickel is then electrowon from the solution. The depleted acid solution is then recycled back to the dissolution step.

Abstract: Technetium is separated from nickel by electro-refining contaminated nickel. Electrorefining controls the electrolyte solution oxidation potential to selectively reduce the technetium from the metallic feedstock solution from Tc(VII) to Tc(IV) forcing it to report to the anodic slimes and thereby preventing it from reporting to the cathodic metal product. This method eliminates the need for peripheral decontamination processes such as solvent extraction to remove the technetium prior to nickel electrorefining. These methods are particularly useful for remediating nickel contaminated by radio-contaminants such as technetium and actinides.

Abstract: Apparatus and method for dewatering radioactive waste slurry solids. The apparatus includes a vacuum pump for applying a vacuum to a suitable flexible filter and collapsible membrane combination in which the slurry solids are contained so that the slurry solids are compressively dewatered when the vacuum is applied. The apparatus further includes a container for suitably storing the resulting dewatered slurry solids.

Abstract: Apparatus and method for dewatering radioactive waste slurry solids. The apparatus includes a vacuum pump for applying a vacuum to a suitable flexible filter and collapsible membrane combination in which the slurry solids are contained so that the slurry solids are compressively dewatered when the vacuum is applied. The apparatus further includes a container for suitably storing the resulting dewatered slurry solids.

Abstract: Apparatus for dewatering radioactive waste slurry solids. The apparatus includes a vacuum pump for applying a vacuum to a suitable flexible filter and collapsible membrane combination in which the slurry solids are contained so that the slurry solids are compressively dewatered when the vacuum is applied. The apparatus further includes a container for suitably storing the resulting dewatered slurry solids.