Thorium vs Uranium
Thorium and Uranium are genuine alternatives to one another — a choice somebody actually makes — and differ on 3 measured properties, mohs hardness most clearly.
Thorium vs Uranium
Thorium
Th
A potential nuclear fuel that is several times more abundant than uranium and has never been commercialised.
Uranium
U
An element used as a yellow glass colourant for a century before anyone knew it was radioactive.
| Property | Thorium | Uranium |
|---|---|---|
| Atomic number | 90 | 92 higher |
| Density Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 19.05 g/cm³ |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 1132 °C |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | about 3 | about 6 higher |
| Molar mass | 232.0377 g/mol | 238.02891 g/mol higher |
Choosing between them
Thorium is recorded as a substitute for Uranium — less supply-constrained, lower environmental impact.
What it gives up: Not fissile. It has to be bred into uranium-233 first, which is why every thorium programme is a proposal.
Partial substitute, on the evidence cited above.