TY - GEN
T1 - Deep disposal of eurobitum bituminised waste
T2 - 2005 - MRS
AU - Weetjens, Eef
AU - Sillen, Xavier
AU - Valcke, Elie
N1 - Score = 1
PY - 2006
Y1 - 2006
N2 - The Eurobitum bituminised waste produced by the former EUROCHEMIC reprocessing plant in Mol-Dessel (Belgium) contains a lot of salts, mainly NaNO3. This NaNO3 may possibly affect significantly the evolution of a radwaste repository through redox and ion exchange reactions with Boom Clay, which in Belgium is studied as a reference host formation. Yet, the leaching behaviour of NaNO3 from the Eurobiturn and its migration in the Boom Clay is rather unclear. Therefore, some scoping numerical calculations have been performed. In a first phase, we calculated the water flux towards the disposal gallery to assess the timescale of the saturation process of the disposal galleries. In a second phase, the leaching rate of NaNO3 out of the drums is compared with its diffusive removal through the Boom Clay. The water flux to the gallery was calculated at approximately 100 ml/day per metre gallery, based on the natural pressure gradient observed around the HADES Underground Research Laboratory. Different approaches were elaborated to find a NaNO3 source term for the diffusion calculations. For various ways of characterising the nitrate release, the numerical calculations generally show that the NaNO3 concentrations in the first decimetres of Boom Clay will not be much higher than 1 M. Moreover, a sensitivity analysis showed that if the nitrate is released from the bituminised waste product within 10 000 years, the Boom Clay controls the concentration profiles; if the release is slower, the source term has a more pronounced effect on the near field concentrations.
AB - The Eurobitum bituminised waste produced by the former EUROCHEMIC reprocessing plant in Mol-Dessel (Belgium) contains a lot of salts, mainly NaNO3. This NaNO3 may possibly affect significantly the evolution of a radwaste repository through redox and ion exchange reactions with Boom Clay, which in Belgium is studied as a reference host formation. Yet, the leaching behaviour of NaNO3 from the Eurobiturn and its migration in the Boom Clay is rather unclear. Therefore, some scoping numerical calculations have been performed. In a first phase, we calculated the water flux towards the disposal gallery to assess the timescale of the saturation process of the disposal galleries. In a second phase, the leaching rate of NaNO3 out of the drums is compared with its diffusive removal through the Boom Clay. The water flux to the gallery was calculated at approximately 100 ml/day per metre gallery, based on the natural pressure gradient observed around the HADES Underground Research Laboratory. Different approaches were elaborated to find a NaNO3 source term for the diffusion calculations. For various ways of characterising the nitrate release, the numerical calculations generally show that the NaNO3 concentrations in the first decimetres of Boom Clay will not be much higher than 1 M. Moreover, a sensitivity analysis showed that if the nitrate is released from the bituminised waste product within 10 000 years, the Boom Clay controls the concentration profiles; if the release is slower, the source term has a more pronounced effect on the near field concentrations.
KW - Bitumens
KW - Nitrate
KW - Simulation
KW - Flow models
KW - Radioactive waste disposal
KW - Boom Clay
KW - Leaching
KW - Diffusion
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_31294
U2 - 10.1557/proc-932-41.1
DO - 10.1557/proc-932-41.1
M3 - In-proceedings paper
SN - 1558998896
SN - 9781558998896
T3 - Materials Research Society Symposium Proceedings
SP - 735
EP - 742
BT - 29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX
PB - MRS - Materials Research Society
CY - Warrendale, United States
Y2 - 12 September 2005 through 16 September 2005
ER -