Chemical and radiation shielding effectiveness of some heavy metal oxide glasses for immobilizing radioactive wastes

Abstract

AbstractCe/Sb/Mn different borate glass systems based PbO in concentrations of 50, 35, and 15 mol%, respectively, were prepared by the melting–annealing method. Wide chemical, structural, and radiation shielding characterizations were studied before and after 120 kGy of gamma radiation to test the possible use of glasses for immobilizing radioactive wastes. The results showed suitable density values ranging from 3.34 to 5.30 g/cm3 increased by irradiation. FTIR spectra revealed high structural stability against irradiation correlated to the trigonal BO3, tetrahedral BO4 groups, high polarizable Pb2+ ions, and the doped metal ions. Unexpectedly, the chemical durability after in situ leaching process in H2O, 0.1 N HCl, and 0.1 N NaOH for ~ 3 months revealed clear improving after irradiation e.g., enhanced by ~ 25% for Ce-lead borate glass. Scanning electron microscope (SEM) images of the glass surfaces revealed more smooth and homogenous surfaces after irradiation. Shielding parameters by Monte Carlo code (MCNP5) and Phy-X/PSD software were studied, e.g., mass and linear attenuation coefficients (MAC and LAC), effective atomic number (Zeff), radiation protection efficiency (RPE%), half and tenth value layers (HVL and TVL), and heaviness%. Comparing the shielding behavior of the three glasses revealed that Ce-lead borate glass has the highest values of LAC, MAC, Zeff, heaviness%, and RPE% and the lowest values of HVL, TVL, and MFP, referring to the best shielding efficiency. The whole study indicates the desired properties of glasses as immobilizers or containers for radioactive wastes, e.g., nuclear medicine units in hospitals, especially lead borate glass doped Ce ions. Graphical Abstract