Modelling the behaviour of host rock for nuclear waste
Nuclear energy is nowadays a crucial issue and the storage of radioactive waste raises many questions. Over the past few decades, many countries have subsequently built underground laboratories allowing them to test hypotheses on a large scale. In Belgium, a decision was taken in 1974 to create the HADES laboratory in the layer of clay situated under the Nuclear Energy Study Centre in Mol, with the first excavation works taking place in the 1980s. The various studies carried out over the past three decades have led to the development of various concepts. This is especially the case regarding the behaviour of the rock that will host the waste. This is due in particular to the development of calculation tools which currently allow the user to model these behaviours fairly accurately, by taking into account the most complex situations, especially in the long term over several tens of thousands of years.
In the first recently-defended thesis(1), Benoît Pardoen focuses on the argillaceous rock that hosts the underground ANDRA laboratory at the site in Bure. He particularly studied the phenomena that occur when this clay is excavated, and during exploitation and maintenance phases. These galleries have to be ventilated, which dries out the rock and thus alters its state; as for the waste, it releases heat, another element to be taken into account during long-term simulation.
(1) Hydro-mechanical analysis of the fracturing induced by the excavation of nuclear waste repository galleries using shear banding, Pardoen Benoît, University of Liège, 2015, doctoral thesis.