[en] A description is given of parameters and results from technical scale experiments (1 kg Na, 531 cm² pool surface area, 481-632⁰C pool temperature, UO₂-, NaI-, SrO-admixtures from 0.2 up to 20 g, 2.2 m³ vessel to be heated up to 130⁰C) and from laboratory scale experiments in a glove box (100 g Na, 38.5 cm² pool surface area, 550⁰C pool temperature, UO₂ and SrO admixtures from 0.2 up to 5 g, with the released quantities being sucked into cold traps and filters). The main objective of the tests was to determine the retention factors RF for U, I and Sr including their time behaviour as well as differences in local deposition. Liquid sodium has a very high retention capability for U and Sr; in the early phase (about 10% of the pool vaporized), RF (U) is of the order of 10³ to 10⁴, and RF (Sr) of the order of 500, with increasing tendencies with time. RF (I), however, was found to be between 1 and 10. The iodine release may be explained by evaporation, whereas strong evidence exists for mechanical release processes (small particle release) in case of UO₂ and SrO. A best-fit formula is given for the specific evaporation rate of sodium, based on its proportionality to the vapor pressure. The sodium aerosol system was investigated with respect to mass concentration, particle size spectrum and deposition behaviour. Model calculations were performed using the PARDISEKO computer code. Agreement with the experiment was achieved after introducing a turbulent deposition module into the code. (orig./HP)