Assessment of granite-kaolin composite bricks as storage barrier facility for liquid radioactive waste

Gamma radiation shielding of baked and unbaked granite bricks produced with 0%, 10%, 20%, 30%, 40%, and 50% of kaolin powder were experimentally and theoretically assessed for possible deployment in liquid radioactive waste storage. A 3 × 3 inches NaI(Ti) detector and WinXCOM program were used to measure the linear attenuation coefficients at different energies. Elements composition of samples were analyzed using particle induced X-ray emission (PIXE) spectroscopy. Results show that adding kaolin to granite positively reduced the liquid permeability coefficients of the bricks but negatively reduced the shielding properties of the bricks. Optimum results were obtained from unbaked sample of granite brick produced with 50% of micro scale kaolin powder (GK50) with mass attenuation coefficient of 0.0663, 0.0572 and 0.0552 cm2.g−1, radiation protection efficiency (RPE) of 38.36%, 34.11% and 33.13% for radiation energies levels of 661.6, 1173.2, and 1332.5 keV respectively and liquid permeability coefficient of 6.53 × 10−11 m.s−1. The study concludes that all brick samples were thermally stable, good in gamma radiation shielding and efficient in liquid radioactive waste immobilization.