Ingestion pathway factor in dose assessment for annual airborne releases of radioactivity

An analytic model is derived for use in a simplified assessment of the committed effective dose equivalent to the public due to routine airborne releases of radioactive materials. The model uses the dosimetry in ICRP Publication 30 and determines the ratio of the committed effective dose equivalent (CEDE) via a specified ingestion pathway relative to that CEDE by inhalation per annual airborne release of a radionuclide. This ratio is defined as the ingestion pathway factor (IPF) and is shown to depend upon the radionuclide annual limits of intake, the atmospheric deposition velocity, and an ingestion parameter, the effective contamination intake area. The IPF values are tabulated for several radionuclides. These resultant IPF values often exceed unity, suggesting that the ingestion path is often the critical or limiting pathway for off-site CEDE to an individual. An application of this assessment is demonstrated in a review of a hypothetical nuclear facility to determine the appropriate extent of radiologic effluent and environmental monitoring at the facility.