Mass spectrometric study of the oxygen potential at the UO2−x–U(l) phase limit

Thermodynamics of the O–U system. IV – Critical assessment of chemical potentials in the U–UO2.01 composition range

“…This uncertainty is at least 10 times lower than the usual ones given for gas phase determinations. Baïchi et al [64] completely confirmed the earlier measurements by Pattoret and Coworkers [59][60][61][62] and had to reject the data of Ackermann et al [58,81].…”

“…In conclusion, we retain the Pattoret, Drowart and Smoes [59][60][61][62] data with their proposed uncertainties and the Baïchi et al [64] values as mentioned in their Table 2. We have to state that these values are pertinent only in the 2000 < T < 2300 K range, since for lower temperatures the UO 2 activity is equal to one.…”

“…Accurate measurements of ionic intensity ratios of UO 2 (g) lead to a small uncertainty, %2800-3000 J mol À1 , as explained by Baïchi et al [64]. This uncertainty is at least 10 times lower than the usual ones given for gas phase determinations.…”

“…Combination of Knudsen cell and mass spectrometric methods, either run in two independent and complementary experiments [58] or coupled in the same apparatus [59][60][61][62][63][64] have been used with the main advantage of being able to analyse the gas phase composition. This gas phase consists of the following species, U(g), UO(g), UO 2 (g) and UO 3 (g).…”

“…It is this solution that has been used recently by Baïchi et al [64] for the study of UO 2 activity in the U-UO 2Àx diphasic domain.…”