Energy Density of Uranium
various contrasting sources
There is no doubt that fissioning 1kg of uranium in a nuclear power station produces more energy than burning 1kg of coal - but how much more?
The links below discuss three very different figures – 60× 16,000× and 2-3 million × more.
Note: it really depends on exactly what you mean by '1kg of uranium' - the refined metal, the fissionable isotopes that make up a small fraction of that… or the unrefined ore dug out of the ground (considering that coal pretty much burns straight out of the ground).