High density concrete incorporating grit scale aggregates for 4th generation nuclear power plants

•Grit scale concrete for 4th generation nuclear power plant is developed.•Mechanical and gamma-ray shielding characteristics at high temperatures.•SEM, XRD, and X-ray on pre-and post-heated concrete.•Improvement in shielding and compressive strength with grit scale aggregates. This study covers development methods and a complete spectrum of physical qualities for 4th generation Nuclear Power Plant (NPP) as potential radiation shielding material at higher temperatures between 200 °C and 1200 °C. The samples were prepared using 25%, 50%, 75%, and 100% heavy density Grit Scale Aggregate (GSA) and three normal-weight concrete mixes. Mass and density loss, compressive strength, X-ray radiography, scanning electron microscopy, attenuation coefficient, half-value layer, and tenth-value layer tests were performed on pre-and post-heated concrete. Significant improvement in shielding characteristics and compressive strength has been achieved for mixes having 50% heavy density grit scale aggregate for pre-and post-heated concrete.