MIGRATION OF TECHNETIUM UNDER DEEP GEOLOGICAL CONDITIONS

Migration behavior of technetium under deep geological conditions was studied experimentally in columns with groundwater and altered graniti c rock sampled from a fracture zone in a granitic pluton at a depth of about 250 m. The experiment was performed in a glove box with a contr olled atmosphere at the 240-m level of the Underground Research Labora tory (URL) near Pinawa, Manitoba, Canada. Technetium was strongly sorb ed on the dark mafic minerals in the column. With the exception of a v ery small unretarded fraction that was eluted with the tritiated water , no further breakthrough of technetium was observed. This strong sorp tion of technetium on the mineral surface was caused by reduction of T c(VII), probably to Tc(IV).