For tritium removal from a self-cooled Pb-17Li blanket of a fusion reactor, permeation into an intermediate NaK loop and precipitation of the tritide in a cold trap are foreseen. First experiments on the kinetics of hydride precipitation showed that i) low supersaturation concentrations are obtained at low concentration ranges, ii) these values are obtained after a very short cold trap loading period. Both results meet essential requirements for fusion blanket cold traps. Theoretical work has shown that two-dimensional calculations (including buoyancy effects) of the temperature, velocity and concentration distributions result in precipitation distributions which differ significantly from those obtained with 1d-models currently used to develop mass transfer relationships.