Novel Shielding Mortars for Radiation Source Transportation and Storage

Abstract

New types of mortar, M1 (60% sand, 25% cement, 10% ball clay, and 15% WO3), M2 (50% sand, 25% cement, 10% ball clay, and 25% WO3), M3 (60% sand, 25% cement, 10% Barite, and 15% WO3), and M4 (50% sand, 25% cement, 10% Barite, and 25% WO3), were prepared and the impact of WO3 and barite on their radiation shielding performance and mechanical properties was evaluated. The radiation attenuation factors were evaluated using five radioactive point sources, and a sodium iodide (NaI) scintillation detector (3″ × 3″) was used to detect the attenuation of gamma ray photons emitted from radioactive sources. The density values of the mortar samples lie within the range of 2.358 and 2.602 g/cm3. The compressive strength and the tensile strength of the prepared mortars increased with the increasing percentage of WO3. The M4 mortar had the highest linear attenuation coefficient (LAC) value. The LAC results demonstrated that adding barite and a high percentage of WO3 into the mortars notably enhanced the radiation shielding performance of the prepared mortar. The relationship between the half value layer (HVL) and the energy is direct, and so was used to calculate the thickness of mortar needed to absorb or scatter half the number of low-energy photons falling on the samples. At 0.06 MeV, the HVL values of the samples were 0.412, 0.280, 0.242, and 0.184 cm for samples M1–M4, respectively. The highest HVL values, obtained at 1.408 MeV, were 5.516, 5.202, 5.358, and 5.041 cm. Thus, a thinner layer of the M4 sample provided comparable attenuation of photons and radiation protection to the thicker M1–M3 samples. The new material is promising as an effective shield of radiation-emitting sources during transportation and long-term storage.