Physical and Chemical Characterization of Actinides in Soil from Johnston Atoll

Abstract

Characterization of the actinide content of a sample of contaminated coral soil from Johnston Atoll, the site of three non-nuclear destructs of nuclear warhead-carrying THOR missiles in 1962, revealed that >99% of the total actinide content is associated with discrete bomb fragments. After removal of these fragments, there was an inverse correlation between actinide content and soil particle size in particles from 43 to 0.4 µm diameter. Detailed analyses of this remaining soil revealed no discrete actinide phase in these soil particles, despite measurable actinide content. Observations indicate that exposure to the environment has caused the conversion of relatively insoluble actinide oxides to the more soluble actinyl oxides and actinyl carbonate coordinated complexes. This process has led to dissolution of actinides from discrete particles and migration to the surrounding soil surfaces, resulting in a dispersion greater than would be expected by physical transport of discrete particles alone.

Solid state speciation and potential bioavailability of depleted uranium particles from Kosovo and Kuwait

“…reversibly sorbed and pH-sensitive) more readily available for extraction than the original particulate material. Carbonates of actinides, such as observed by Wolf et al (1997) for instance, are dissolved in the 0.16 M HCl solvent. Furthermore, the size distribution of the DU particles in the investigated samples, which is known to be a key property with respect to solubility, is not fully characterised.…”

Nature of nano-sized plutonium particles in soils at the Hanford Site

“…Plutonium has complex chemical and physical properties and there is great interest in its long-term safe handling. Microanalysis studies at the Nevada Test Site [1,2], Johnston Atoll [3] and at the Mayak production facility [4] have provided unique insight into the nature of plutonium in the environment and its ability to be transported as colloids. Within the 200 area at the Hanford site in eastern Washington State, the 216 Z-Plant area, also termed the Plutonium Finishing Plant, conducted plutonium recovery operations that resulted in organic and aqueous wastes being disposed at several "cribs" or ground trenches.…”

“…With the aid of high angle annular dark-field scanning-TEM (HAADF-STEM) for location of the heavy elements [2,3,9] and electron energy-loss spectroscopy (EELS) to determine oxidation states elements [10,11], additional data on the nature of contaminants may be obtained. With environmental specimens containing a variety of different amorphous or partially crystalline contaminant particles, this method can be used to investigate phases that may not be readily discernible with X-ray diffraction or XAS.…”

Prediction of Binding Stability of Pu(IV) and PuO2(VI) by Nitrogen Tridentate Ligands in Aqueous Solution

“…The nuclear power industry faces challenges related to the irradiation of nuclear fuels by used fuel recycled by a pyroprocessing system or PUREX (Pu and U Extraction) system. Liquid waste from these systems contains highly toxic actinides, including Pu, which must be effectively extracted for reuse via a closed-loop recycling program, such that it does not contaminate the environment [5][6][7][8][9]. The efficiency of such programs depends on effective recycling of the spent nuclear fuel by separating the fissile Pu, which is formed by neutron capture reactions and is intended for subsequent use in a fast neutron reactor.…”