OXYGEN POTENTIAL MODEL FOR STOICHIOMETRIC AND NON-STOICHIOMETRIC URANIUM DIOXIDE
The principal results of this investigation are: The establishment of a model from which can be calculated the oxygen partial pressure over stoichiometric and nearly stoichiometric urania, given the values of the relevant equilibrium constants at the temperatures of interest; a semi-empirical deduction of oxygen potential values over stoichiometric UO-2, ("TRIANGLE"G-O2 (x = O,T)), in which, for the first time, the existence of a systematic uncertainty, x-O in the experimentally determined degree of non-stoichiometry, x-m, is taken into account; the deduced values of "TRIANGLE"G-O2 (x = O,T) are thus claimed to be the most reliable currently available, certainly up to 2500 K and probably up to the melting point; and: a rationalization, in terms of the model and x-O, of all existing "TRIANGLE"G-O2 (x-m = O,T) data + the highly non- systematic T dependence exhibited by diverse data being shown to be a consequence of the variation of x-O from experiment to experiment, according to the varying degree to which the adopted stoichiometric reference approximates to the true stoichiometric state; in the case of data confined to one side of x-m = O, it is found that x-O is positive in the case of hyperstoichiometric material, and negative for hypo.
Bibliographic Reference: EUR 9410 EN (1984) MF, 60 P., BFR 120, BLOW-UP COPY BFR 300, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124029800 / Last updated on: 1987-01-01
Available languages: en