Particle Size (Sieving) and Enthalpy (Acid Calorimetry) Analysis of Single-Pull K East Basin Floor and Pit Sludges

Bredt, Paul R.; Delegard, Calvin H.; Schmidt, Andrew J.; Silvers, K.L.; Thornton, Brenda M.; Gano, Sue

doi:10.2172/15003687

Cited by 1 publication

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Initial estimates of the concentrations of uranium metal in K Basin sludge were attempted through reaction calorimetry Bredt et al 2000; Appendix B of Plys and Schmidt 2006). In this technique, samples of sludge were reacted with concentrated nitric acid (HNO 3 ) and the elevation in temperature measured.…”

Section: Uranium Metal Concentration By Reaction Calorimetrymentioning

confidence: 99%

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

Delegard

Schmidt²

2008

Self Cite

View full text Add to dashboard Cite

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...

show abstract

Section: Uranium Metal Concentration By Reaction Calorimetrymentioning

confidence: 99%