Effect of using heavy aggregates on the high performance concrete used in nuclear facilities

Abstract

For nuclear power plants construction, each country has to make use of its own available raw materials. Therefore, through the current research we had to search for the relevant local materials suitable for usage as concrete components and satisfy the needed requirements. The target of this research is to investigate the effect of some type’s heavy aggregates on the physico-mechanical properties and attenuation coefficient of the high performance heavy concrete used as radiation shielding of nuclear facilities. For this purpose radiation shielding properties of high performance heavy concrete mixture prepared using different types of heavy aggregates such as magnetite in addition to industrial waste of lead slag as a coarse aggregate and fine aggregate of local sand or replacing sand by fine magnetite or lead slag, were investigated comparatively with hardened dolomite concrete. The physico-mechanical properties of type aggregates and hardened concretes were examined. Gamma transmission parameters for the studied concrete for Cs137 and Co60 as gamma source were measured, also the effective removal cross-section (ΣR) of fast neutrons spectra for a wide range of neutron energies of [2–12 MeV] with thicknesses 4, 6, 8, 10 and 12 cm of heavy concrete mixes for Plutonium-Beryllium as neutrons source. While the thermal neutrons tests were performed using californium radioisotope. An innovative material that the current research has introduced to be used as a heavy coarse aggregate in HPC is “lead slag”, lead slag has been converted from a subsidiary industrial and environment polluting waste to a very valuable material as one of the ingredients of heavy concrete. It was found that, the magnetite and lead slag aggregates improved the physico-mechanical properties of heavy concrete compared to dolomite concrete. Replacing fine sand by the fine aggregates of magnetite or lead slag enhances the efficiency of attenuation by the concrete mixes against these radiations and the compressive strength values increase by 12 and 27% respectively, of heavy concrete after 28 days. The concrete mix containing lead slag aggregate has higher mechanical properties and enhances the attenuation properties for fast neutrons, gamma rays and thermal neutrons than the other concrete mixes.