Potential importance of resuspension during chronic releases to the atmosphere

During chronic releases of radionuclides to the atmosphere, airborne concentrations and resulting radiation exposures are often calculated by assuming that the contributions from resuspended activity are negligible compared with the contributions from direct atmospheric transport. In this paper, models which have been proposed to describe resuspension are used to estimate air concentrations and radiation exposures from resuspension for a chronic release time corresponding to an operating lifetime of a nuclear facility. The potential importance of resuspension is assessed by comparing the results with the same quantities from direct atmospheric transport. Application of available resuspension models to long-term chronic releases to the atmosphere results in resuspension concentrations which cannot be neglected compared with concentrations from direct atmospheric transport. If the resuspension factor is to be used in radiological assessments, further investigation into the proper values of the deposition velocity, initial resuspension factor, and resuspension decay constant for use in the models is needed. In the absence of a verified resuspension model, Horst has shown that resuspension can be conservatively accounted for by calculating air concentrations from direct transport without depletion due to deposition