Fate of Radionuclides at the GTS
The radionuclides we add can have several fates and the waste treatment we use depends on the physical and chemical properties of the radionuclides used.
Much of the work at the Grimsel Test Site (GTS) has involved short half-life tracers, which decay very quickly to non-radioactive forms. Radioactive tracers with longer half lives are taken to the Paul Scherrer Institute (PSI) for treatment and final disposal.
Removal of cores from the Excavation Project
In specific cases (e.g. Excavation Project), where the radionuclides are held very tightly by the rock, the whole rock mass can be immobilised via injection of an epoxy resin. The area of rock containing the radionuclides is then physically removed by taking large (30 cm diameter) cores of rock (which also contains the radionuclides) from the GTS.
Overview of the overcoring procedure
The extracted cores can then be analysed by very precise radiochemical techniques, which allow the sites of radionuclide retardation to be observed.