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 ۰%‎, ‎۱۰%‎, ‎۲۰%‎, ‎۳۰%‎, ‎۴۰%‎, ‎and ۵۰% of kaolin powder were experimentally and theoretically assessed for possible deployment in liquid radioactive waste storage‎. ‎A ۳×۳ 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 ۵۰% of micro scale kaolin powder (GK۵۰) with mass attenuation coefficient of ۰.۰۶۶۳‎, ‎۰.۰۵۷۲ and ۰.۰۵۵۲ cm۲.g-۱‎, ‎radiation protection efficiency (RPE) of ۳۸.۳۶%‎, ‎۳۴.۱۱% and ۳۳.۱۳% for radiation energies levels of ۶۶۱.۶‎, ‎۱۱۷۳.۲‎, ‎and ۱۳۳۲.۵ keV respectively and liquid permeability coefficient of ۶.۵۳×۱۰-۱۱ m.s-۱‎. The study concludes that all brick samples were thermally stable‎, ‎good in gamma radiation shielding and efficient in liquid radioactive waste immobilization‎.

Keywords:

Granite , Kaolin , Gamma shielding , Radioactive waste management , Liquid Permeability