The low figure of CO2 usage often cited is based on an estimation you can read at https://onlinelibrary.wiley.com/doi/full/10.1111/j.1530-9290.... I don't remember it giving a clear estimate on how much it rises, but that is understandable, as already the current estimate is not a reliable figure.

But it's the wrong comparison. Nuclear energy is not to be replaced with fossil energy, but with renewables. So that "advantage" is completely irrelevant.