Appropriate concrete for nuclear reactor shielding

• Construction materials constitute a large portion of radioactive wastes.
• The trace elements with large neutron activation cross-sections were defined in limestone.
• Limestone is favorable to be used in shielding concretes in NPPs.
• 152Eu is the main source for a long term activity in limestone concrete.
• Locally, Al-Tamoura site for limestone quarries is the most suitable for low-activation concrete.

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 ∑(Ci/CLi)≤1 at thermal neutron flux less than 107 (n cm−2 s−1), while the limestone from other the three sites has ∑(Ci/CLi)≤1 at a flux less than 3×106 (n cm−2 s−1).