International Comparison of Computer Codes for Modelling the Dispersion and Transfer of Tritium Released to the Atmosphere

Abstract

Computer codes for modelling the dispersion and transfer of tritium released to the atmosphere were compared. The codes^a originated from Canada, the United States, Sweden and Japan. The comparisons include acute and chronic emissions of tritiated water vapour or elemental tritium from a hypothetical nuclear facility. Individual and collective doses to the population within 100 km of the site were calculated. The discrepancies among the code predictions were about one order of magnitude for the HTO emissions but were significantly more varied for the HT emissions. Codes that did not account for HT to HTO conversion and cycling of tritium in the environment predicted doses that were several orders of magnitude less than codes that incorporate this feature into the model.