Author(s)

M. W. Evans

Abstract

As part of its mandated public health mission, ATSDR must determine whether historic air emissions from the Oak Ridge Gaseous Diffusion Plant represented a public health hazard to adjacent communities. ORGDP produced enriched uranium via gaseous or thermal diffusion of uranium hexafluoride (UF6; which undergoes rapid atmospheric transformation into hydrogen fluoride and uranium oxides). The dose reconstruction was accomplished using established air dispersion models and site-specific meteorological and historic air monitoring data to verify the use of both the modelling tools and the emission estimates. Air concentrations and doses to radionuclides were estimated using the standard air dispersion models. Meteorological data are from multiple weather years for two on-site stations. The Department of Energy has been collecting environmental measurements in soil, air, and water since at least 1953. Two stations adjacent to ORGDP were sampled for airborne gross alpha particulates since at least the mid-1960s. With some simplifying assumptions, there is good agreement between the historic gross alpha concentrations and those predicted from dispersion modelling. When combined with health-protective exposure assumptions, the estimated emission data and dispersed air concentrations provide a reliable basis for the public health determinations at this site. Keywords: uranium hexafluoride, historic monitoring, dispersion modelling, dose reconstruction, air emissions.

Keywords

uranium hexafluoride, historic monitoring, dispersion modelling, dose reconstruction, air emissions.