PROCESS DEVELOPMENT QUARTERLY REPORT. PART I. LABORATORY WORK
The fraction of uranium in Vitro, Climax, Uravan, and Uranium Reduction concentrates insoluble in nitric acid was not decreased by digestion pressures of 70 to 100 psig and digestion temperatures up to approximately 170 deg C. The rate of solution of the soluble uranium was, however, improved by these more severe digestion conditions. Evaluation of samples of plant streams indicate that the decontamination efficiency of the Weldon Spring refinery is principally limited by entrainment of aqueous phase during the extraction operations rather than by any chemical effects. The measurement of x-ray-diffraction line profiles of UO/ sub 2/ provides a technique for measuring the relative importance of crystallite size and lattice strain in determining the reactivity of UO/sub 3/. The specific conductance of hydrofluoric acid solutions ranging in concentrations from 10 to 40% was measured over the temperature range 30 to 90 deg C. These data were needed to provide a control mechanism for the low excess acid flow sheet. The hydrogen contamination in metal from laboratory scale bombs is increased by increasing the hydrogen pressure in the bomb prior to firing. The decrease in pressure observed during firing correlates well with the quantity of hydrogen in the metal produced. Metal yields fall off with increased prefiring pressure. Correlation of metal hydrogen with bomb center temperature at firing was good, and showed a correspondence between plant and laboratory bombs. The addition of UF/sub 3/ to bomb or liner drastically shortened the pre-heat time before firing. Diffusion coefficients for hydrogen in uranium were measured in the alpha, beta, and gamma phases. Values for dingot metal range from 6.4 x 10/sup -5/ sq cm/sec at 800 deg C to 1.5 x 10/sup -4/ sq cm/sec at 970 deg C. Hydrogen was found to be soluble in molten magnesium fluoride to the extent of 32 ppm at a pressure of 760 mm of Hg at a temperature of 1265 deg C. This solubility is a linear function of the hydrogen partial pressure. Combination of these results with those for hydrogen solubility in molten uranium indicates that the hydrogen distribution in the dingot is not an equilibria. Formation of magnesium hydride was found to occur by reaction of hydrogen with finely divided magnesium obtained by thermal decomposition of magnesium hydride. With magnesium of normal surface area, the hydridirg reaction occurs at too slow a rate to be significant. The evaluation of x-ray methods for predicting the dimensional stability of uranium fuel elements under irradiation was begun. Instrumental conditions and the choice of calculation strategy greatly alter the values obtained for the Texture Coefficient, and hence the evaluation of the growth potential of a particular structure. The rate of dissolution of uranium metal in nitric acid is catalyzed by moderate pressures of NO/sub 2/. The use of dibenzoylmethane to determine uranium in the range of 0.03 to 0.3 mg is being investigated. The precision at the 95% confidence level is plus or minus 0.01 mg of uranium. Only vanadium(V), antimony(V), mercury (II), cerium(IV), and thorium(IV) cause serious intenference problems.
- Research Organization:
- Mallinckrodt Chemical Works, St. Louis
- DOE Contract Number:
- W-14-108-ENG-8
- NSA Number:
- NSA-14-021547
- OSTI ID:
- 4165172
- Report Number(s):
- MCW-1425
- Resource Relation:
- Other Information: Decl. May 12, 1960. Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANTIMONY
ARYL RADICALS
BENZOYL RADICALS
CERIUM
CONTAMINATION
DECOMPOSITION
DECONTAMINATION
DIFFRACTION
DIFFUSION
FUEL ELEMENTS
HEATING
HYDROFLUORIC ACID
HYDROGEN
MAGNESIUM FLUORIDES
MAGNESIUM HYDRIDES
MEASURED VALUES
MERCURY
METALS
METHANE
NITRIC ACID
NITROGEN OXIDES
ORE PROCESSING
PRESSURE
QUALITATIVE ANALYSIS
SENSITIVITY
SOLUBILITY
SOLUTIONS
SOLVENT EXTRACTION
STABILITY
THORIUM
URANIUM DIOXIDE
URANIUM FLUORIDES
URANIUM ORES
URANIUM TRIOXIDE
VANADIUM
X RADIATION