Decontamination method of radioactively contaminated materials

Metal ions leached from plant constituent materials to reactor primary coolants are gradually deposited in primary circuits in a state that metal ions are mixed with iron oxides, to form obstinate oxidized coating layers. In order to remove radioactive materials intruded into such oxide coating layers, the radiation-contaminated materials are brought into contact with electrostatically charged water to make the radioactive materials free and remove them from the surface of the contaminants. That is, if metal oxides such as Fe2O3 are brought into contact with electrostatically charged water, e- is applied to the oxide, and water molecules return to a stable state, as well as Fe2O3 is reduced from Fe+3 to Fe+2, to cause structural change in the tissues of the oxide coating layers. This can change the property of the oxide coating layers and easily remove them by washing, and radioactive materials intruded between oxide particles are removed simultaneously. (T.M.)