Open AccessEvaluation of the area factor used in the RESRAD code for the estimation of airborne contaminant concentrations of finite area sources
Author(s) -
Yi-Jia Chang,
Chunna Yu,
S. K. Wang
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.2172/676907
Subject(s) - environmental science , radionuclide , scale factor (cosmology) , precipitation , shape factor , hydrology (agriculture) , mixing (physics) , deposition (geology) , meteorology , atmospheric instability , wind speed , soil science , atmospheric sciences , geology , mathematics , geotechnical engineering , geography , geometry , physics , sediment , paleontology , cosmology , quantum mechanics , metric expansion of space , dark energy
The area factor is used in the RESRAD code to estimate the airborne contaminant concentrations for a finite area of contaminated soils. The area factor model used in RESRAD version 5.70 and earlier (referred to as the old area factor) was a simple, but conservative, mixing model that tended to overestimate the airborne concentrations of radionuclide contaminants. An improved and more realistic model for the area factor (referred to here as the new area factor) is described in this report. The new area factor model is designed to reflect site-specific soil characteristics and meteorological conditions. The site-specific parameters considered include the size of the source area, average particle diameter, and average wind speed. Other site-specific parameters (particle density, atmospheric stability, raindrop diameter, and annual precipitation rate) were assumed to be constant. The model uses the Gaussian plume model combined with contaminant removal processes, such as dry and wet deposition of particulates. Area factors estimated with the new model are compared with old area factors that were based on the simple mixing model. In addition, sensitivity analyses are conducted for parameters assumed to be constant. The new area factor model has been incorporated into RESRAD version 5.75 and later