Modelling the SEALEX experiments at Tournemire URL

The SEALEX experiments investigate the performance of sealing systems for radioactive waste disposal facilities. Quintessa has recently published two papers which use numerical modelling to analyse data from the experiments and contribute to understanding the processes observed.

Quintessa has recently published two papers in Environmental Earth Sciences reporting modelling of the SEALEX experiments, run by IRSN (Institut de Radioprotection et de Sûreté Nucléaire), at the Tournemire Underground Research Laboratory (URL). This work was carried out by Quintessa on behalf of RWM through the DECOVALEX-2015 international research and model comparison collaboration. The SEALEX experiments are designed to improve understanding of the controls on the long-term performance of bentonite-based seals.

The first paper, 'Engineered damage zone sealing during a water injection test at the Tournemire URL', analyses data from a water injection test designed to measure permeability of the Toarcian argillite in which the SEALEX experiments are conducted. The analysis combined with numerical modelling of the test show that the damage zone around the test borehole seals over the first year of the experiment. This gives an insight into the permeability enhancement in the damage zone and the timescales over which it may persist.

The second paper, 'A new hydro-mechanical model for bentonite resaturation applied to the SEALEX experiments', uses data from a range of laboratory and in-situ experiments to improve understanding of bentonite resaturation. The experiments involved bentonite seals first swelling into void space around the seals and then swelling pressures building up once the voids were closed. Quintessa developed a novel approach to representing the hydro-mechanical behaviour of the bentonite which worked well for the experiments in the SEALEX programme.

Image courtesy of IRSN.