Cleaning Decontamination Of Radioactive Contamination Of Soil

During the decommissioning of nuclear facilities, it is an important step to decontaminate the soil contaminated by radioactive nuclides. Decontaminating the contaminated soil can eliminate the further pollution of surroundings, and ensure the safety of the decommissioning operators and the people around.In China Institute of Atomic Energy, there are about 1000m~3 excavated soil contaminated by radioactive nuclides, because of different unexpected accidents. If the soil is stored for a long time, not only it would take up much land, but also be a potential threat to surroundings. Presently, such kind of research in China has being made only for treatment of industrial waste contaminated by heavy metal ions. However the studies on decontamination of radioactive contaminated soil has not been reported. So this research is meaningful and necessary to meet the requirements of soil decontamination in China.There are many kinds of technologies for decontaminating contaminated soil, such as chemical decontamination, physical decontamination and other kinds of decontamination technologies. In this research, some contaminated soil in CIAE, which was contaminated mainly with ~137Cs, was decontaminated by soil washing .By screening the contaminated soil, it is separated to different granular size group, and decontaminated by washing with water and chemical regents separately. The experimental results are shown as following:The activity distribution of radioactive nuclides in soil is inverse ration with granular size of soil;The efficiency of physical decontamination is in ration with granular size of soil, but the decontamination efficiency is limited;The decontamination efficiency of the chemical reagents to soil contaminated ~137Cs can reach to 99%;The decontamination efficiency of the chemical reagents is related to reagents concentration, decontamination time and temperature, and the flow rate of decontamination solution.