Long Term Diffusion (LTD) Phase I Update

Circulation of a cocktail of sorbing, weakly sorbing and non-sorbing radionuclides (³H, ²²Na, ¹³¹I, ¹³⁴Cs) in the monopole of work-package 1 was started on 7th June, 2007 and will continue until June 2008.

Water samples retrieved twice a month and more frequently in the first two months are currently being analysed at the Paul Scherrer Institute (PSI) to ascertain the amount of sorption and diffusion.

Field activities in other work packages are now complete.

Laboratory analyses of C-14 and NHC-9 resin impregnated overcores and other rock samples are being carried out in order to improve knowledge of matrix porosity and to refine predictive diffusion models carried out before the start of each in situ experiment.

Start of radionuclide injection on 7th June, 2007

In order to examine the effect of flow wetted surfaces (FWS) on the extent of diffusion, dipole experiments are planned for Phase II (from 2009) where sorbing and safety relevant radionuclides will be circulated in a shear zone.