Abstract: A method of effectively decontaminating a substance contaminated with radioactivity, in particular, shot blasting grit contaminated with radioactivity, and a decontaminating apparatus which makes it possible for a single apparatus to perform all of the decontamination processes without moving the contaminated substance from one apparatus to another for each process, thereby realizing reduction in the installation space and achieving an improvement in operational efficiency. The method comprises: decontaminating a contaminated substance by washing it with achelate liquid; draining the chelate liquid; raising the temperature of the substance to a level not lower than the boiling point of a solvent by means of hot air; supplying the solvent to the substance to result in rapid vaporization thereof; removing the remaining chelate fluid liquid by the force of this vaporization and draining the same;and drying the substance.

Abstract: The present invention is directed to an apparatus for decontaminating radioactive items such as parts and machinery including means for shotblasting or sandblasting to remove the radioactivity, means for cleaning the substance with a cleaning solution, means for washing the grit used to shotblast or sandblast with a washing solution, means for filtering the washing solution, and means for decontaminating the filtered washing solution by purifying it. The apparatus includes means for decontaminating washing solution to allow reuse thereof.

Abstract: Applying shotblast or sandblast to a substance contaminated with radioactivity, cleaning the substance with a liquid, washing the grit of shotblast or sandblast with an organic solvent, filtering the resulting organic solvent, decontaminating the organic solvent itself by distilling the organic solvent filtered, and using this decontaminated solvent for washing said grit.

Abstract: A radioactive decontamination method for decontaminating a radioactive-contaminated object by using methylene chloride in place of conventionally used hydrocarbon fluoride or perchloroethylene. The radioactive-contaminated object is impacted by methylene chloride solution. Before the impacting, a preparatory step is executed as required in which radioactive contaminant, which is usually radioactive-contaminated epoxy-resin paint layer on a part used in a nuclear facility, is impregnated with methylene chloride solution so as to swell, thus facilitating exfoliation of the contaminant from the object. The methylene chloride solution is filtered and distilled so as to be decontaminated and subjected to a repeated use for impacting the radioactive-contaminated object.