title: An analytically based model for the simultaneous leaching-chain decay of radionuclides from contaminated ground surface soil layers.
abstract: This paper describes an analytically based method for modeling the time-dependent radionuclide areal densities of contaminated soil surface layers when the soil experiences simultaneous leaching, surface erosion and chain radioactive decay. The model is used to predict time-dependent radionuclide areal densities in a volcanic ash blanket contaminated with spent nuclear fuel particles for the purpose of assessing the risks of radiation exposure from an extrusive volcanic event near a proposed high-level waste repository at Yucca Mountain. The method uses general analytical solutions (an expansion of the Bateman equations) for calculating serial decay, including non-radioactive decay loss terms, in order to calculate time-dependent radionuclide areal densities in the ash blanket. In the presented example, 43 "key" radionuclides are tracked and their concentrations in the blanket are displayed for a 10,000-y time period following the volcanic event. Although the analysis presented herein is for modeling contaminated volcanic ash blankets, the model would work equally well for modeling time-dependent radionuclide contamination of land surfaces in, for example, site decommissioning. It is suggested that the general solutions for serial decay (with non-radioactive decay loss terms) can also be used to model the release of radionuclides from the waste packages under anticipated repository conditions.
authors.affiliation: Southwest Research Institute-Center for Nuclear Waste Regulatory Analyses, San Antonio, TX 78238-5166, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Jarzemba
authors.forename: R D
authors.initials: RD
authors.lastname: Manteufel
mesh_terms: D008962:Models, Theoretical; D011829:Radiation Dosage; D011850:Radioactive Waste; D011851:Radioactivity; D011868:Radioisotopes / Q000032:analysis / Q000737:chemistry*; D018570:Risk Assessment; D012990:Soil Pollutants, Radioactive; D012995:Solubility; D013781:Texas; D013997:Time Factors; D018707:Volcanic Eruptions
chemical_list: D011850:Radioactive Waste; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive