Nuclear energy may not even be carbon neutral

Greenhouse gases are emitted in all stages of the lifecycle of a nuclear reactor: construction, operation, fuel production, dismantling and waste disposal. Leaving out any of these five stages will bias estimates towards lower values.
The last two contributions, dismantling and waste disposal are particularly difficult to estimate. Not many commercial reactors have been fully decommissioned. Also there is still no scientific or political consensus on the approach to be used for the long-term storage of waste.
The fuel preparation contribution is also problematic. Considerable amounts of carbon are released in the mining, milling and separation of the uranium from the ore. Also the carbon emitted is very dependent on the concentration of uranium in the ore.
It's important to appreciate that these three problematic contributions, fuel production, dismantling and waste disposal are either non-existent or small contributions in the case of electricity generation by renewable technologies. Estimates of the carbon footprint of renewably generated electricity therefore should be much more reliable than those for nuclear.

https://theecologist.org/2015/feb/05/false-solution-nuclear-power-not-low-carbon