TY - GEN
T1 - The osmosis-induced swelling and NaNO3 leaching of radioactive and artificially aged Eurobitum bituminized waste
AU - Mariën, An
AU - Valcke, Elie
AU - Bleyen, Nele
AU - Smets, Steven
N1 - Funding Information:
This work is undertaken in close co-operation with, and with the financial support of ONDRAF/NIRAS, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials, as part of its programme on geological disposal of medium-level long-lived waste. The discussions on the results and experimental set-up with Sebastià Olivella and Nadia Mokni (UPC), and with Xiangling Li (EURIDICE EIG, SCK•CEN) are greatly appreciated.
PY - 2012
Y1 - 2012
N2 - The behavior of Eurobitum bituminized radioactive waste under geological disposal conditions is studied in water uptake tests at the Belgian Nuclear Research Centre SCK•CEN to assess the feasibility of geological disposal for the long-term management of this waste. The hydro-mechanical behavior of this 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.
AB - The behavior of Eurobitum bituminized radioactive waste under geological disposal conditions is studied in water uptake tests at the Belgian Nuclear Research Centre SCK•CEN to assess the feasibility of geological disposal for the long-term management of this waste. The hydro-mechanical behavior of this 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.
KW - Bituminous materials
KW - Radioactive Waste
KW - Waste Disposal
UR - http://www.scopus.com/inward/record.url?scp=84868568760&partnerID=8YFLogxK
U2 - 10.1557/opl.2012.563
DO - 10.1557/opl.2012.563
M3 - In-proceedings paper
AN - SCOPUS:84868568760
SN - 9781605114521
VL - 1475
T3 - Materials Research Society Symposium Proceedings
SP - 113
EP - 118
BT - Scientific Basis for Nuclear Waste Management XXXV
PB - MRS - Materials Research Society
T2 - 2012 MRS Spring Meeting
Y2 - 9 April 2012 through 13 April 2012
ER -