Appropriate concrete for nuclear reactor shielding

A survey for the neutron activation significant trace-minerals in limestones from different sites in Syria has been carried out. The specific saturation activation radioactivity was calculated and compared to the clearance levels. The results show that the limestone composition varies significantly from one site to another. For example Al-Tamoura site has Sigma(C-i/CLi) <= 1 at thermal neutron flux less than 10(7) (n cm(-2) s(-1)), while the limestone from other the three sites has Sigma(C-i/CLi) <= 1 at a flux less than 3 x 10(6) (n cm(-2) s(-1)). (C) 2015 Elsevier Ltd. All rights reserved.