Investigation of Soil Corrosivity Effect on Low Radioactive Wastes Burial Casks

In this study, corrosion of AISI st37 steel waste casks was investigated by analyzing the physico-chemical characteristics of the soil medium. The chemical composition of soil has important effects on steel casks. Moisture, soil electrical resistivity, soluble salts, chlorides, pH, redox potential and anions and cations content, as the major parameters, influence the exterior corrosion of waste casks. To carry out this research, the corrosivity of the soil in the central desert regions of Iran has been studied using the AWWA C105 standard. In these regions, 4 samples have been collected at varied points located in the vicinity of the site, named CR1, CR2, CR3 and CR4. At first, for a better assessment of the soils corrosivity, the physical and chemical analyses were conducted on the soil and in the solutions prepared from the soil samples. Then, the rate of corrosion was measured by the weight loss and potentiodynamic polarization methods. The obtained results showed that the CR4 soil sample with the lowest electrical conductivity, compared with the other samples, has the lower corrosion rate in the whole method. Corrosion rates of the samples in this region in the 180-day weight loss method, and in the electrochemical method are equal to 0.0625 and 0.029 mm/y, respectively.