NAGRA Opalinus Clay (…002 - Version 1
FEP 13.4.3 Intrusion of saline groundwater

An increase of salinity in the groundwater may decrease the sorption constant of some radioelements on the clay, in particular of those sorbing via the cation exchange mechanism (e.g. Cs). A very high salinity may also adversely affect the swelling property of bentonite seals and backfill. An intrusion of saline water from imperfectly sealed aquifers cannot be ruled out completely. However, the salinity of these groundwaters is similar to or lower than the salinity of the host rock pore water. Therefore no detrimental effects are expected.