A treatment method that includes soil containing clay and silt and reduces the radioactive substance of the object to be treated incorporating the radioactive substance to a safe level in the living environment

摘要

PROBLEM TO BE SOLVED: To reduce a radioactive substance of a processed object including a soil including clay or silt and taking in the radioactive substance down to a safety level in a living environment.SOLUTION: The process method is configured to: sort a processed object including soil including clay or silt and taking in a radioactive substance into a coarse particle processed object from which the radioactive substance can be eliminated only by a cleaning, or the processed object from which the radioactive substance can be eliminated only by the cleaning or a part serving as most of the coarse particle processed object and the processed object (thereafter referred to as "a first processed object") and a fine processed object from which the radioactive substance cannot be eliminated only by the cleaning, or the processed object from which the radioactive substance cannot be eliminated only by the cleaning or a part serving as most of the coarse particle processed object and the processed object (thereafter referred to as "a second processed object"); clean the first processed object with cleaning liquid; perform a heating treatment to the second processed object at a critical temperature or lower of water, water soluble liquid or a compound of the water and the water soluble liquid (thereafter "the water, the water soluble liquid or the compound of the water and the water soluble liquid" is referred to as "an aqueous liquid") in a pressure state at a saturation vapor pressure or higher and, rapidly release the pressure after the heating treatment; and separate a compound of the second processed object and the water soluble liquid to a liquid content and a solid content.