Colloids from the aqueous corrosion of uranium nuclear fuel

Kaminski, Michael; Dimitrijević, Nada M.; Mertz, Carol J.; Goldberg, Margaret M.

doi:10.1016/j.jnucmat.2005.07.009

Cited by 31 publications

(30 citation statements)

References 12 publications

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“…Similar sub-micron particles, found to be UO 2.08±0.03 , were generated during 90°C reaction of irradiated N Reactor fuel in water (Kaminski et al 2005). The agglomerates of fine particles in Figure 3.3 thus may be the black UO 2.x product solids from uranium metal fuel corrosion.…”

Section: Sem/eds Examination Of the Kc-2/3 M250 Sludge And Test 1 Andmentioning

confidence: 66%

“…Uranium metal fuel corrosion under anoxic and starved oxygen conditions has been studied in the laboratory , Kaminski et al 2005, and others) and shown to produce UO 2.x . Aside from the conversion of uranium metal to UO 2.x , uranium compound alterations similar to those shown in Figure 3.10 also have been observed in the laboratory from the interaction of non-irradiated UO 2 and irradiated UO 2 with Yucca Mountain groundwaters (Wronkiewicz et al 1992, in natural uranium mineral deposits (e.g., Leslie et al 1993), and in related studies.…”

Section: Uranium Phase Observations In the Present Testingmentioning

confidence: 99%

“…The corrosion of both non-irradiated and irradiated cladding-free N Reactor fuel pieces was studied under immersed 90°C hydrothermal conditions in both deionized water and J-13 (Yucca Mountain) well water (Kaminski et al 2005). The corrosion test products were examined by XRD to show that the only direct reaction product from uranium corrosion had the uraninite structure with formula UO 2.08±0.03 .…”

Section: Uranium Metal Corrosionmentioning

confidence: 99%

“…The corrosion products, when viewed under transmission electron microscopy (TEM), were small spheres primarily <10 nm (i.e., <0.01 μm) in diameter with some 100-150 nm UO 2 particles, i.e., in the colloidal particle size range (Kaminski et al 2005). Most of these individual particles were agglomerated to sizes ranging from ~0.25 to 1.0 μm.…”

Section: Uranium Metal Corrosionmentioning

confidence: 99%

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Hydrothermal Testing of K Basin Sludge and N Reactor Fuel at Sludge Treatment Project Operating Conditions

Delegard¹,

Schmidt²,

Thornton³

2007

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Executive SummaryFive bench-scale tests (~50 ml each) were conducted in sealed, un-agitated reaction vessels using sludge samples collected from the K East Basin and particles/coupons of irradiated N Reactor fuel (also from the K Basins). These tests were designed to evaluate and understand the chemical changes that may be occurring under the hydrothermal conditions (e.g., 7 to 72 h at 185°C) of the Sludge Treatment Project (STP) corrosion process and the effects that any changes would have on sludge rheological properties. The two sludge formulations used in these tests were selected to represent nominal (vs. bounding) compositions of the two major sludge feed streams to the STP process. The scoping tests were not designed to evaluate engineering aspects of the process.The hydrothermal treatment affected the chemical and physical properties of the sludge. In each test, significant uranium compound phase changes were identified, resulting from dehydration and chemical oxidation and reduction reactions. Physical properties of the sludge were significantly altered from their initial, as-settled, sludge values including, shear strength, settled density, weight percent water, and gas retention.The high uranium content sludge (~70 wt% uranium) set up to form a very stiff solid that exhibited very high shear strength (120,000 to 170,000 Pa) after hydrothermal treatment at 185°C for 7 to 10 hours under static (unstirred) conditions. Shear strengths of untreated sludge range from about 270 to 8100 Pa. Also, the hydrothermal treatment reduced the water content in the settled sludge by about 20 wt%. The treated sludge was difficult to remove from the Teflon test vessels, with sludge firmly adhering to the Teflon vessel surfaces. The strength of the treated sludge was further evaluated by agitation in water. In a 600-ml beaker, with 400 ml water at ~30°C, the diameters of agglomerates were reduced by about 40 to 50% after 1 hour of agitation with a 5.08-cm (2-in.) diameter impeller rotated at a tip speed of 80 cm/s.Further static tests with lower uranium-content sludges (~16 wt% uranium) run 72 h at 185°C produced softer solids with 9,000 to 16,000 Pa shear strengths. While some sludge adhered to the Teflon liner, it was not tenaciously bound. The agglomerates from these tests were relatively weak and, in some cases, were disintegrated with a gentle stream of water. The water content in the settled sludge was not significantly affected by the hydrothermal treatment.Chemical phase alteration, observed by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry, gave evidence that solids dissolution followed by precipitation was responsible for the increased strengths of the sludge products. The presence of organic ion exchange resin (OIER) and polymer flocculent (constituents known to be in K Basin sludge) in the lower uranium-content sludge did not appear to have a significant impact on the physical behavior of the post-treated sludge.Four irradiated uranium metal fuel coupons were included in on...

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Section: Sem/eds Examination Of the Kc-2/3 M250 Sludge And Test 1 Andmentioning

confidence: 66%

Section: Uranium Phase Observations In the Present Testingmentioning

confidence: 99%

Section: Uranium Metal Corrosionmentioning

confidence: 99%

Section: Uranium Metal Corrosionmentioning

confidence: 99%

See 2 more Smart Citations

Hydrothermal Testing of K Basin Sludge and N Reactor Fuel at Sludge Treatment Project Operating Conditions

Delegard¹,

Schmidt²,

Thornton³

2007

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“…According to transmission electron microscopy, the reaction product particle size was <10 nm within ~150-nm agglomerates (Kaminski et al 2005). …”

Section: Reaction Mechanism Thermodynamics Stoichiometry and Produmentioning

confidence: 99%

Uranium Metal Reaction Behavior in Water, Sludge, and Grout Matrices

Delegard

Schmidt²

2008

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This report was originally published in September 2008. In May 2009, it was discovered that, in the introductory paragraphs of Section 2.1, the units for the reaction enthalpy of uranium metal with water to form uranium dioxide and hydrogen and the reaction enthalpy of hydrogen with oxygen to form water were incorrectly given as kcal/mole rather than kJ/mole. This version of the report, Revision 1, corrects the units for both enthalpies to kJ/mole. Other small editorial changes also were made.iii SummaryThis report summarizes information and data on the reaction behavior of uranium metal in water, in water-saturated simulated and genuine K Basin sludge, and in grout matrices. This information and data are used to establish the technical basis for metallic uranium reaction behavior for the K Basin Sludge Treatment Project (STP). The specific objective of this report is to consolidate the various sources of information into a concise document to serve as a high-level reference and road map for customers, regulators, and interested parties outside the STP (e.g., external reviewers, other DOE sites) to clearly understand the current basis for the corrosion of uranium metal in water, sludge, and grout.The generation of hydrogen gas through oxidation/corrosion of uranium metal by its reaction with water can potentially create a flammable atmosphere during sludge handling, grouting, or subsequent transport and storage operations. Consequently, a thorough understanding of the uranium metal content and its reaction behavior, both in sludge and in grouted sludge matrices, is essential to the process designs and for management of sludge. Results of studies of this reaction and its characteristics have been reported in the technical literature for over 60 years. More focused studies of the reaction in simulated and genuine K Basin sludge and in grout matrices have been conducted in the past 10 years. The outcomes of these studies, provided in the present review, show that: The reaction of uranium metal with anoxic liquid water is highly exothermic and produces stoichiometric uranium dioxide (UO 2 ) and hydrogen. The reaction apparently proceeds through a uranium hydride intermediate that can sequester part of the hydrogen during the initial reaction. The corrosion reaction occurs isotropically such that the uranium particle size decreases at a constant rate at a given temperature. Based on a survey of 32 studies giving 128 data points, the corrosion rate follows an Arrhenius dependence on temperature (i.e., the logarithm of the rate is proportional to the inverse absolute temperature) from at least 24°C to 350°C. The rate law was adopted for the STP. A 95% confidence level on the predicted rate is plus/minus about a factor of three. The STP rate law is essentially the same as used in the application to license the Yucca Mountain repository. Dissolved oxygen inhibits the reaction of uranium metal with liquid water, but the more rapid anoxic reaction can follow the lower oxic rates at times that are difficult to predict...

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