You haven't understood his post, he is correct under worst-case scenario for nuclear -> once through fuel cycle achieves 5% burnup, that's 4 million MJ/KG, or

You haven't understood his post, he is correct under worst-case scenario for nuclear -> once through fuel cycle achieves 5% burnup, that's 4 million MJ/KG, or roughly 60MWd/kg Enrichment requires that we throw away most of uranium as depleted uranium, that's what he means by "7.4:1 tails/fuel ratio" That's gives us ~20 years of power at 1KW, but we have are converting to electricity, so it really only gives us 6 years or so. The main flaw with his argument is, in my understanding, he assumes a once-through fuel cycle, whereas France and others reprocess nuclear fuel. It also discards reactors that work on un-encirched uranium like CANDU. I am not sure about the ores, but I am greatfull for the detailed writeup https://en.wikipedia.org/wiki/CANDU_reactor https://en.wikipedia.org/wiki/CANDU_reactor