Investigation of penetration mechanisms of radionuclides in concrete and their leaching behaviour

Penetration profiles for Cs and Sr in concrete of the strength class B 35 have been determined. Capillary suction experiments with both radionuclides 137Cs/85Sr and natural Cs/Sr have been performed in parallel. Fully characterized cylindrical concrete specimens were in contact with solutions containing the species of interest under well-defined conditions. Different processing techniques have been applied for active and non-active samples followed by gamma spectrometry and atom absorption spectroscopy respectively. Both routes provided satisfactory results, being in good agreement and demonstrating the distinct behaviour of the two elements. Similar work with Co, I and U will be reviewed in near future. (orig.)