Shame I am work at the moment.
When I studied RE we looked at all firms of electricity production. Nuclear, when generating is very low CO2 generation. The long term storage is a problem, mainly political, latest idea is to bury it in the Irish Sea mudstone. It may happen.
There is a question mark over the security of uranium supplies, processing, transport and storage.
Regarding the excess thermal energy heating the atmosphere, not really. But local heating is a problem, as is excess air temperature. A French reactor was on reduced power because it could not get enough cooling. All large thermal plants cab suffer from that.
The main thing is to reduce the CO2e gasses and particulates. These are the main problems.
CO2e gasses do not act like a blanket, depending on which model used to calculate, it really just allows more energy to be stored kinetically (temperature is the mean free path speed of molecules after all).