Evaluation of the radiological risk resulting from road transportation of tritiated water

A probability model for the evaluation of the individual radiological risk resulting from road transportation of tritiated water in 200-liter drums is presented. In order to evaluate such risk, an evaluation must be made of the probability for an individual to be involved in the consequences of a radiological transport accident, to incur a given dose and to suffer deleterious effects resulting from the dose incurred. With the purpose of quantifying the importance of accidents, a severity level classification was adopted as a function of the fraction of liquid volume spilled as a result of the accident. Considering the above-mentioned severity classification and the transported volume, the volume and the spill area are implied, while the soil characteristics are taken into account. By evaluating the spill characteristics, the average meteorological conditions in the area under analysis and the activity concentration of the transported liquid, the activity concentration values for tritium in air may be estimated, thus allowing calculation of the effective dose equivalent to be incurred by the individual who is most exposed to the consequences of an associated event. As a result of the summarized analysis above, a value of the individual risk per unit of activity concentration is obtained for tritium and for a given volume of transported liquid. 8 references