Behaviour of Composites Used in the Confinement of Nuclear Wastes 1 ‐ Water Absorption of Polymer Matrices

The diffusion of water into typical epoxide and polyester materials has been studied as a function of temperature, temperature cycles and polymer structure. A reversible uptake characterised by a diffusion coefficient and an equilibrium absorption was accompanied by an irreversible water uptake due to hydrolysis. Polyesters showed a pronounced tendency to degradation, particularly above room temperature. This preliminary investigation was conducted within the broader scope of a study dealing with the feasibility of embedding nuclear wastes in polymer matrices. The results obtained thus far are encouraging, notably with epoxide networks.