ABSTRACT

The investigation of gamma radiation shielding and liquid permeability properties of kaolin, granite and their composites for radioactive waste management is an environmental engineering strategy for radioactive risk management. In this research, gamma radiation shielding properties and liquid permeability coefficients of compacted baked and unbaked granite powder treated with 0%, 10%, 20%, 30%, 40%, 50% 60%, 70%, 80%, 90%, 100%, of kaolin powder were investigated for possible deployment in radioactive waste management. A 3 x 3 inches Thallium Activated Sodium Iodide NaI(Ti) detector was used to measure the linear attenuation coefficients of all samples at commonly used gamma radiation energies of 661.6 keV, 1173.2 keV and 1332.5 keV. The elemental compositions of all samples were analyzed using Particle Induced X-ray Emission Spectroscopy (PIXE). The experimentally measured values for radiation attenuation coefficients were in good agreement with the theoretical results base on relative deviation values less than 6%. The study concludes that, unbaked samples were more efficient than baked samples in gamma radiation shielding and that all unbaked samples were good for radioactive waste management with optimum result obtained from compacted granite treated with 50% of micro scale kaolin powder with  linear attenuation coefficient (LAC) 0.1700cm-1, 0.1469 cm-1, 0.1416 cm-1 and radiation protection efficiency (RPE) of 38.88%, 34.59% and 33.64% for gamma radiation energies levels of 661.6 keV, 1173.2 keV, and 1332.5 keV respectively and liquid permeability coefficient of 6.53 x 10-11 m/s. Comparing results obtained in this study with other results from available literature, granite and kaolin composites performed better than most materials and therefore should be deployed as a valid alternative to other radiation shielding materials used in liquid radioactive waste management.