TABLE 3.
Atomic % of Th and O, ratio [O]/[Th] and speciation of oxygen (as atomic percent of oxide, hydroxide and water) as calculated from the Th 4f and O 1s lines in the XPS measurements. Relative error of atomic concentrations is within ± (10–20) %.
| Solid phase | Atom % Th | Atom % O | Ratio [O]/[Th] | O2- (%) | OH− (%) | H2O (%) |
|---|---|---|---|---|---|---|
| ThO2(s, hyd, fresh, T = 22°C) | 27.6 | 72.4 | 2.6 | 43.3 | 47.9 | 8.8 |
| ThO2(s, hyd, aged, t = 1 m, pHm = 3, T = 80°C) | 30.4 | 69.6 | 2.3 | 56.1 | 30.5 | 13.4 |
| ThO2(s, hyd, aged, t = 1 m, pHm = 12.8, T = 80°C) | 28.7 | 71.3 | 2.5 | 63.5 | 29.8 | 6.7 |
| ThO2(s, hyd, aged, t = 2 m, pHm = 3, T = 80°C) | 29.7 | 70.3 | 2.4 | 59.3 | 31.6 | 9.1 |
| ThO2(s, hyd, aged, t = 2 m, pHm = 12.8, T = 80°C) | 26.1 | 73.9 | 2.8 | 57.0 | 33.8 | 9.2 |
| ThO2(s, hyd, aged, t = 4.5 m, pHm = 3, T = 80°C) | 28.0 | 72.0 | 2.6 | 55.6 | 30.8 | 13.6 |
| ThO2(s, hyd, aged, t = 4.5 m, pHm = 12.8, T = 80°C) | 29.3 | 70.7 | 2.4 | 55.6 | 26.9 | 17.5 |
| ThO2(s, hyd, aged, t = 5.5 m, pHm = 3, T = 80°C) | 29.0 | 71.0 | 2.5 | 64.0 | 28.9 | 7.1 |
| ThO2(s, hyd, aged, t = 5.5 m, pHm = 12.8, T = 80°C) | 28.6 | 71.4 | 2.5 | 58.4 | 31.6 | 10.0 |