METHOD FOR DECONTAMINATING RADIOACTIVE MATERIAL CONTAMINATED OBJECT

PROBLEM TO BE SOLVED: To provide a method for decontaminating a radioactive material contaminated object, which is based on a decontamination technique such as a high pressure washing using water appropriate for usage in a living area, has a good removal effect on radioactive cesium, is capable of being performed with a practical cost, and do not adversely affect the environment after the performance.SOLUTION: Nano-bubble water is used which includes fine air bubbles with a modal particle size of 500 nm or less and total particle number concentration of 10particles per milliliter or more are dispersed in water. Radioactive material is washed out by immersing, in the nano-bubble water, a radioactive material contaminated object to which radioactive material was attached to be contaminated, so as to elute the radioactive material or by causing the nano-bubble water to flow on a surface of the radioactive material contaminated object. Preferably, the nano-bubble water includes the fine air bubbles with a modal particle size of 70-200 nm and total particle number concentration of 1.0×10particles per milliliter or more and 1.5×10particles per milliliter or less.