[en] A simple Gaussian plume model was used to predict the concentration distribution of releases of elemental tritium into surrounding environment from two different sources. The Monte Carlo simulation approach was used to capture the effect of uncertainties caused by the input parameters. The simulation results indicated that the releases in general caused very low doses. However the ambiguity regarding the chemical form of tritium entails the greatest uncertainties in the calculations in comparison to estimated uncertainties in the input parameters. The dose conversion coefficient for tritiated water is four orders of magnitude greater than for elemental tritium, which makes the assumption of the amount of uptake of tritiated water in the lung critical for the calculations. Consequently the maximum doses may range from nSv to μSv per year. Therefore further studies are needed to achieve more realistic assumptions and to validate the model to be able to reduce the predicted uncertainties