Samples of simulated vitrified radioactive waste have been prepared containing, separately, neptunium, plutonium and technetium. These glasses have been leached in static granite groundwater for 150 days. The resulting solutions have been characterised with respect to both the ionic and colloidal species: these solutions have then been contacted with concrete and granite to produce initial measurements of the source term from a typical repository. The results show that (a) the colloidal species arise from detached particles of the so-called gel layer on the surface of the glass, (b) e solution activities were 590 Bq.ml-1 in the case of 99Tc and 20 Bq.ml-1 for 237Np, and (c) the sorption coefficients wIre 1.4 and > 300 ml.g for concrete and 0.4 and 8.3 ml.g-1 for granite respectively. The technetium was only weakly sorbed and the neptunium strongly sorbed in each case.