MODELING SOIL/RADIONUCLIDE REMOVAL FOR YUCCA MOUNTAIN BIOSPHERE DOSE ASSESSMENTS

摘要

Estimates of annual rates of soil loss from land resources in Amargosa Valley, NV were calculated for use in assessing potential radionuclide build up in soils resulting from irrigation with contaminated groundwater. The estimates were based upon soil properties obtained from existing surveys and tolerable annual soil loss rates for these soils based upon their resiliency to surface soil removal by erosion and other processes. The annual soil loss estimates were then coupled with estimates of potential contaminant build up in the surface 15-cm soil due to continuous irrigation with contaminated groundwater. The analysis showed that there is no need to consider soil removal in subsequent dose calculations for those radionuclides predicted to yield low degrees of net build up (less than approximately 20%) over the time required for the establishment of new equilibrium soil contaminant levels. However, the cumulative effects of annual surface soil removal can have a significant effect on dose assessment for those radionuclides predicted to have contaminant build up times that are long in comparison to the time required for complete removal of the surface soil layer.