NAGRA Opalinus Clay (…002 - Version 1
FEP 12.4.4 Chemical plume from ILW​

Geochemical reactions due to a high-pH plume from cement dissolution can lead to changes in porewater composition and in mineral composition (dissolution, secondary minerals) and can therefore change sorption and solubility properties for radioelements. Usually the porosity is also affected. The organic content of the ILW waste is too small to lead to an organic plume. The nitrate content of some waste types may be high enough to lead to a temporary plume, potentially leading to oxidising conditions (catalysed by microbes).