NAGRA Opalinus Clay (…002 - Version 1
FEP 8.2.3 Mineralogical alteration - short term​​

Alteration of bentonite minerals could potentially lead to a reduction of bentonite swelling properties and/or plasticity. Short-term processes that must be considered include thermally induced shrinkage cracking, alteration and reduction in swelling capacity during the unsaturated phase and illitisation during the high temperature period (the first few hundred years). However, these processes have no effect on long-term safety.