TY - JOUR T1 - Docking Sr-90 radionuclide in cement: An atomistic modeling study JF - Physics and Chemistry of the Earth Y1 - 2014 A1 - Youssef, Mostafa A1 - Roland Jean-Marc Pellenq A1 - Bilge Yildiz KW - Cement KW - mechanical properties KW - Molecular simulation KW - Nuclear waste storage AB -

Cementitious materials are considered to be a waste form for the ultimate disposal of radioactive materials in geological repositories. We investigated by means of atomistic simulations the encapsulation of strontium-90, an important radionuclide, in calcium silicate hydrate (C-S-H) and its crystalline analog, the 9 angstrom-tobermorite. C-S-H is the major binding phase of cement. Strontium was shown to energetically favor substituting calcium in the interlayer sites in C-S-H and 9 angstrom-tobermorite with the trend more pronounced in the latter. The integrity of the silicate chains in both cementitious waste forms were not affected by strontium substitution within the time span of molecular dynamics simulation. Finally, we observed a limited degradation of the mechanical properties in the strontium-containing cementitious waste form with the increasing strontium concentration. These results suggest the cement hydrate as a good candidate for immobilizing radioactive strontium. (C) 2013 Elsevier Ltd. All rights reserved.

VL - 70-71 ER -