Development and Performance Assessment of a Soil Washing Equipment for Soil Contaminated With Radionuclide

The purpose of this study is to develop a soil washing system and to define the most suitable experimental conditions for the individual elemental equipment in a soil washing system for decontaminating the radioactive soil from around a TRIGA (Training, Research, Isotope, General Atomic) reactor in Korea. Analysis results have shown that the main radionuclides were Cs¹³⁷ and Co⁶⁰, the soil particle size ranges from 0.063 mm to 1.0 mm and the radioactive concentration was the strongest in a soil particle smaller than 0.063 mm as predicted. Meanwhile, an oxalic acid was found to be the most efficient chemical agent for washing, especially of cobalt. The scrubbing time of four hours was an optimum time to obtain a removal efficiency of more than 75% for ¹³⁷Cs and ⁶⁰Co. A mixing ratio of the soil weight to the volume of the oxalic acid solution, 1:10, was observed to be the best for a washing and it was estimated to be reasonable for 2 cycles of a scrubbing with 1.0M of oxalic acid to avoid a generation of an excessive waste-solution.