A test for several collimator materials is planned to be performed in the HiRadMat facility of CERN/SPS. Before these samples can be brought to a surface laboratory for analysis after the irradiation, a certain cool-down period has to be respected in order to avoid unjustified exposure of personnel to residual radiation. In the present document, the results of Monte Carlo simulations performed for the radiological assessment of this experiment, are being presented.