Rocky Flats closure: The role of models in facilitating scientific communication with stakeholder groups

Clark, David L.; Choppin, Gregory R.; Dayton, Christine S.; Janecky, David R.; Lane, L. J.; Paton, Ian

doi:10.1016/j.jallcom.2007.02.121

Cited by 10 publications

(11 citation statements)

References 9 publications

(10 reference statements)

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“… 31 A “soil action level” of 1850 Bq/kg plutonium was established in 2002 at Rocky Flats (site 7), located near the city of Denver, USA. 8 Similar to the LFBG, this site has been subjected to encroachment by residential suburbs. Prior to cleanup, extensive sampling of Rocky Flats soils, which involved compositing 25 evenly spaced samples, yielded a mean 239+240 Pu value of 1924 Bq/kg.…”

Section: Resultsmentioning

confidence: 99%

“… 6 At some legacy sites, particularly in North America, remediation has been undertaken, 7 often with extensive public involvement and consultation. 8 While the most contaminated sites (such as Hanford) have received the most attention, there are examples of USA sites where contamination involving relatively small quantities of Pu (such as an estimated 86 g of Pu at the Rocky Flats ‘903 Pad’) have nevertheless received costly remediation. 8 As well as remediation of former waste sites, disposal practices at operational sites have been modified with a greater emphasis on engineered containment, such as at Drigg in the United Kingdom.…”

Section: Introductionmentioning

confidence: 99%

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Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Payne

Harrison

Hughes

et al. 2013

Environ. Sci. Technol.

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Radioactive waste containing a few grams of plutonium (Pu) was disposed between 1960 and 1968 in trenches at the Little Forest Burial Ground (LFBG), near Sydney, Australia. A water sampling point installed in a former trench has enabled the radionuclide content of trench water and the response of the water level to rainfall to be studied. The trench water contains readily measurable Pu activity (∼12 Bq/L of 239+240Pu in 0.45 μm-filtered water), and there is an associated contamination of Pu in surface soils. The highest 239+240Pu soil activity was 829 Bq/kg in a shallow sample (0–1 cm depth) near the trench sampling point. Away from the trenches, the elevated concentrations of Pu in surface soils extend for tens of meters down-slope. The broader contamination may be partly attributable to dispersion events in the first decade after disposal, after which a layer of soil was added above the trenched area. Since this time, further Pu contamination has occurred near the trench-sampler within this added layer. The water level in the trench-sampler responds quickly to rainfall and intermittently reaches the surface, hence the Pu dispersion is attributed to saturation and overflow of the trenches during extreme rainfall events, referred to as the ‘bathtub’ effect.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Payne

Harrison

Hughes

et al. 2013

Environ. Sci. Technol.

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“…296 This work substantiated earlier assessments that solute transport models were not applicable to plutonium migration in Rocky Flats soils. 297,298 Rather, particulate transport was suggested to be the dominant transport mechanism for plutonium migration at the site, although more recent studies suggest that transport of plutonium colloids facilitated by NOM 299 or by complexation to biologically produced, cutin-like ligands 300 may be more important than transport by purely inorganic colloids. These findings of colloid transport in surface waters translated directly into substantial cost savings because they allowed the remediation contractors to focus efforts on erosion modeling and the construction of dams and barriers to control particulate transport rather than removing huge quantities of soil from the site or implementing very costly soil-washing procedures, which would likely be ineffective because of the insoluble nature of PuO 2 (s).…”

Section: Groundwater At Fry Canyon Utmentioning

confidence: 99%

Environmental Speciation of Actinides

Bargar²,

2012

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Although minor in abundance in Earth's crust (U, 2-4 ppm; Th, 10-15 ppm) and in seawater (U, 0.003 ppm; Th, 0.0007 ppm), light actinides (Th, Pa, U, Np, Pu, Am, and Cm) are important environmental contaminants associated with anthropogenic activities such as the mining and milling of uranium ores, generation of nuclear energy, and storage of legacy waste resulting from the manufacturing and testing of nuclear weapons. In this review, we discuss the abundance, production, and environmental sources of naturally occurring and some man-made light actinides. As is the case with other environmental contaminants, the solubility, transport properties, bioavailability, and toxicity of actinides are dependent on their speciation (composition, oxidation state, molecular-level structure, and nature of the phase in which the contaminant element or molecule occurs). We review the aqueous speciation of U, Np, and Pu as a function of pH and Eh, their interaction with common inorganic and organic ligands in natural waters, and some of the common U-containing minerals. We also discuss the interaction of U, Np, Pu, and Am solution complexes with common Earth materials, including minerals, colloids, gels, natural organic matter (NOM), and microbial organisms, based on simplified model system studies. These surface interactions can inhibit (e.g., sorption to mineral surfaces, formation of insoluble biominerals) or enhance (e.g., colloid-facilitated transport) the dispersal of light actinides in the biosphere and in some cases (e.g., interaction with dissimilatory metal-reducing bacteria, NOM, or Mn- and Fe-containing minerals) can modify the oxidation states and, consequently, the behavior of redox-sensitive light actinides (U, Np, and Pu). Finally, we review the speciation of U and Pu, their chemical transformations, and cleanup histories at several U.S. Department of Energy field sites that have been used to mill U ores, produce fissile materials for reactors and weapons, and store high-level nuclear waste from both civilian and defense operations, including Hanford, WA; Rifle, CO; Oak Ridge, TN; Fernald, OH; Fry Canyon, UT; and Rocky Flats, CO.

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“…[1][2][3] For example, self-heating of nuclear fuel 4 following loss of coolant may be lessened by employing advanced reactor fuels with characteristics similar to the UO 2 high burn-up structure (HBS), in which UO 2 fuel evolves into a hierarchical, mesoporous material with 1 mm pores distributed throughout a nanocrystalline UO 2 solid. 1,5,6 Actinide nanoparticles are also known to play a major role in the migration of radionuclides through environmental systems, [7][8][9][10][11] and have been proposed as agents for targeted alpha-therapy, [12][13][14][15][16][17] and for applications in thermopower 18 and heterogeneous catalysis. [19][20][21][22][23][24] Further innovation in these areas will require methods to synthesize and characterize actinides at the nanoscale, an area that is relatively unexplored and beyond current predictive capabilities.…”

Section: Introductionmentioning

confidence: 99%

Structural properties of ultra-small thorium and uranium dioxide nanoparticles embedded in a covalent organic framework

et al. 2020

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Rocky Flats closure: The role of models in facilitating scientific communication with stakeholder groups

Cited by 10 publications

References 9 publications

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Environmental Speciation of Actinides

Structural properties of ultra-small thorium and uranium dioxide nanoparticles embedded in a covalent organic framework

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