Th
Thorium
Z = 90 · Actinide · 232.0 u
Nuclear Engineering Significance
Fertile material in the thorium fuel cycle. Th-232 captures neutrons to produce Pa-233, which decays to fissile U-233. Thermal absorption (σ_a = 7.4 b) is higher than U-238 (σ_a = 2.7 b), giving thorium better conversion characteristics in thermal spectra. ThO₂ has a higher melting point than UO₂, offering safety advantages.
Basic properties
- Atomic number (Z)
- 90
- Standard atomic mass
- 232.0 u
- Category
- Actinide
Isotopes & cross-section data
View in ALLEN →| Isotope | Mass (A) | Half-life | ZAID | Libraries | σ(E) |
|---|---|---|---|---|---|
| Th-229 | 229 | 7920 y | .80c.71c | View → | |
| Th-230 | 230 | 7.538e4 y | .80c.71c.70c | View → | |
| Th-232 | 232 | 1.405e10 y | .80c.71c.70c | View → |