Granular solid targets made of fluidised tungsten powder have been long proposed and are being studied as an alternative configuration towards high-power (>1MW beam power) target systems, suitable for a future Super Beam facility or Neutrino Factory. A feasibility experiment to evaluate this kind of target is being prepared to be performed at HiRadMat facility of CERN/SPS. Activation studies in order to assess the radiological risk from this experiment have been carried out, in order to estimate the necessary cooling time to access and handle the experimental equipment, and for defining the specialized laboratory class for the post-mortem examination of the sample.