How mobile is tritiated water through unsaturated cement-based materials? New insights from two complementary approaches

S. Savoye (1, 2) , A. Rajyaguru (1, 2) , N. Mace (1, 2) , S. Lefevre (1, 2) , G. Spir (1, 2) , J.C. Robinet (3)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 SECR - Service d'Etudes du Comportement des Radionucléides
3 ANDRA

This work presents two complementary approaches (for low and high desaturation) to study tritiated water (HTO) diffusion through unsaturated cement-based materials. The first approach was based on through-diffusion experiments where suction was controlled by osmosis. In the second approach, diffusion experiments were performed in humidity chambers controlled by under-saturated saline solutions. Results revealed a decrease of effective diffusion coefficient by a factor of 10 from 100% to 23% of saturation degree. Comparison with gaseous H$_2$ suggests that HTO diffuses through unsaturated cement-based materials at rates 4 orders of magnitude lower.

Keywords: Tritiated water (HTO); Diffusion; Cement; Desaturation; Osmosis; Saline solution

Domains: Nuclear Experiment [nucl-ex]; Nuclear Theory [nucl-th]

S. Savoye, A. Rajyaguru, N. Mace, S. Lefevre, G. Spir, et al.. How mobile is tritiated water through unsaturated cement-based materials? New insights from two complementary approaches. Applied Radiation and Isotopes, 2017, 139, pp.98-106. ⟨10.1016/j.apradiso.2018.04.019⟩. ⟨cea-02421724⟩