Abstract: Currently, specific activity model is used to assess the dose due to atmospheric tritium release, and the uncertainty of the selected model parameters will cause variability of the dose assessment results. Considering the differences in environmental parameters of different sites, the key parameters in the atmospheric tritium dose assessment model that are affected by the site were analyzed for sensitivity and uncertainty of the dose assessment results. The results show that the humidity of the ambient air at the site has the greatest influence on the dose evaluation results of atmospheric tritium. As the humidity of the site rises, the ingestion internal dose due to atmospheric tritium discharge decreases, and the uncertainty of the dose calculation results also decreases. It was also shown that at low humidity site, the focus should be on the measurement and selection of empirical constants for the proportion of HTO retained in the soil. At high humidity plant site, the focus should be on the measurement and selection of the crop water equivalent factor and the concentration ratios for HTO intake. Thus, the uncertainty of the dose assessment results should be minimized.

Key words: tritium, evaluation, parameter sensitivity analysis