Semi-automated uranium analysis by a modified Davies--Gray procedure
To rapidly and reliably determine uranium in fuel materials a semi-automated implementation of the Davies-Gray uranium titration was developed. The Davies-Gray method is essentially a three step procedure. First uranium is reduced quantitatively from +6 valence to +4 valence by excess of iron (II) in strong phosphoric acid in the absence of nitrite. Prior to the uranium reduction nitrite is destroyed by addition of sulfamic acid. In the second step iron (II) is selectively oxidized to iron (III) by nitric acid in the presence of Mo (VI) catalyst. Finally after dilution to reduce phosphate concentration, the uranium is titrated to U (VI) by standard dichromate. The original sluggish colorimetric endpoint determination used by Davies and Gray is seldom used since New Brunswick Laboratory discovered that addition of vanadium (IV) just prior to titration sufficiently improves reaction rate to allow a potentiometric endpoint determination. One of the advantages of the Davies-Gray uranium titration is that it is quite specific for uranium, most common impurity elements do not interfere with the analysis, and specifically high levels of Pu, Th, and Fe are tolerated.
- Research Organization:
- Hanford Engineering Development Lab., Richland, Wash. (USA)
- DOE Contract Number:
- EY-76-C-14-2170
- OSTI ID:
- 5266415
- Report Number(s):
- HEDL-SA-1221; CONF-7706109-1
- Country of Publication:
- United States
- Language:
- English
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Determination of uranium in uranium metal, uranium oxides, and uranyl nitrate solutions by potentiometric titration
INSTRUMENTAL METHODS OF URANIUM ANALYSIS
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ACTINIDES
AUTOMATION
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
ELEMENTS
EPITHERMAL REACTORS
FAST REACTORS
FFTF REACTOR
FUEL PELLETS
LIQUID METAL COOLED REACTORS
METALS
OXIDATION
PELLETS
REACTORS
REDUCTION
RESEARCH AND TEST REACTORS
RESEARCH REACTORS
SODIUM COOLED REACTORS
TEST REACTORS
TITRATION
URANIUM