Uptake of trivalent actinides (curium(III)) by hardened cement paste: a time-resolved laser fluorescence spectroscopy study.

The curium(III) interaction with cement was investigated using time-resolved laser fluorescence spectroscopy at trace concentrations. Four different Cm(III) species were identified: a nonfluorescing species which corresponds to curium hydroxide real colloids, which were characterized in detail by laser-induced breakdown detection (LIBD), a fluorescing Cm(III)/portlandite sorption species, and two fluorescing Cm(III)/calcium silicate hydrate (CSH) species. From the fluorescence emission lifetimes it is predicted that the two fluorescing Cm(III)/CSH species have one to two and no water molecules, respectively, left in their first coordination sphere, suggesting that these species are incorporated into the CSH structure.