Open AccessCorrosion of Uranium in Desert Soil, with Application to GCD Source Term M
Author(s) -
Herbert Anderson,
Julianne Baca,
J. A. Krumhansl,
Harlan W. Stockman,
Mollie E. Thompson
Publication year - 1999
Language(s) - English
Resource type - Reports
DOI - 10.2172/13957
Subject(s) - uranium , dissolution , depleted uranium , leaching (pedology) , corrosion , uranium oxide , electron microprobe , actinide , weathering , radioactive waste , soil water , gypsum , carbonate , uranium ore , mineralogy , chemistry , geology , metallurgy , materials science , geochemistry , nuclear chemistry , soil science
Uranium fragments from the Sandia Sled Track were studied as analogues for weapons components and depleted uranium buried at the Greater Confinement Disposal (GCD) site in Nevada. The Sled Track uranium fragments originated as weapons mockups and counterweights impacted on concrete and soil barriers, and experienced heating and fragmentation similar to processes thought to affect the Nuclear Weapons Accident Residues (NWAR) at GCD. Furthermore, the Sandia uranium was buried in unsaturated desert soils for 10 to 40 years, and has undergone weathering processes expected to affect the GCD wastes. Scanning electron microscopy, X-ray diffraction and microprobe analyses of the fragments show rapid alteration from metals to dominantly VI-valent oxy-hydroxides. Leaching studies of the samples give results consistent with published U-oxide dissolution rates, and suggest longer experimental periods (ca. 1 year) would be required to reach equilibrium solution concentrations. Thermochemical modeling with the EQ3/6 code indicates that the uranium concentrations in solutions saturated with becquerelite could increase as the pore waters evaporate, due to changes in carbonate equilibria and increased ionic strength