The hydro-mechanical behavior of Eurobitum bituminized radioactive waste is affected by the continuous evolution of the rheological properties of bitumen due to radio-oxidation (i.e. ageing). The effect of the bitumen ageing degree on the kinetics of the water uptake, swelling and NaNO3 leaching is investigated in water uptake tests with ~30 years old radioactive samples and inactive samples that were artificially aged. The first results of swelling and NaNO3 leaching of (i) radioactive samples that have been hydrated for more than 2 years at a constant total stress of 2.2 MPa, and (ii) a thermally aged sample that has been hydrated for ~1.5 years under nearly zero effective stress conditions, revealed lower swelling and higher leach rates for these samples compared to non-aged samples. The effect of ageing on the osmotic efficiency of bitumen as a semi-permeable membrane is less pronounced when swelling of the samples is limited, and changes in time, probably because of the formation of low porosity layers, which seems to mask the difference in bitumen membrane efficiency of aged and non-aged bituminized waste.
|Title of host publication||Scientific Basis for Nuclear Waste Management XXXV. Symposium Proceedings. Volume 1475|
|Place of Publication||Warrendale, PA, United States|
|State||Published - Jan 2012|
|Event||XXXV International Symposium "Scientific Basis for Nuclear Waste Management”, MRS 2011 - Materials Research Society, Buenos Aires|
Duration: 2 Oct 2011 → 7 Oct 2011
|Conference||XXXV International Symposium "Scientific Basis for Nuclear Waste Management”, MRS 2011|
|Period||2011-10-02 → 2011-10-07|